2007-06-12 13:07:21 +00:00
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public
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* License v2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public
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* License along with this program; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 021110-1307, USA.
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*/
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2008-01-08 20:46:30 +00:00
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#ifndef __BTRFS_CTREE__
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#define __BTRFS_CTREE__
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2007-02-02 14:18:22 +00:00
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2007-12-18 21:15:09 +00:00
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#include <linux/version.h>
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2007-10-15 20:18:55 +00:00
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#include <linux/mm.h>
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#include <linux/highmem.h>
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2007-03-22 16:13:20 +00:00
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#include <linux/fs.h>
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2007-08-29 19:47:34 +00:00
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#include <linux/completion.h>
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2008-03-26 14:28:07 +00:00
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#include <linux/backing-dev.h>
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2008-07-17 16:53:50 +00:00
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#include <linux/wait.h>
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2007-10-15 20:14:27 +00:00
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#include <asm/kmap_types.h>
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2008-01-24 21:13:08 +00:00
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#include "extent_io.h"
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2007-10-15 20:14:19 +00:00
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#include "extent_map.h"
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2008-06-11 20:50:36 +00:00
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#include "async-thread.h"
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2007-03-22 16:13:20 +00:00
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2007-03-16 20:20:31 +00:00
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struct btrfs_trans_handle;
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2007-03-22 19:59:16 +00:00
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struct btrfs_transaction;
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2007-05-02 19:53:43 +00:00
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extern struct kmem_cache *btrfs_trans_handle_cachep;
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extern struct kmem_cache *btrfs_transaction_cachep;
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extern struct kmem_cache *btrfs_bit_radix_cachep;
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2007-04-02 14:50:19 +00:00
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extern struct kmem_cache *btrfs_path_cachep;
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2008-07-17 16:53:50 +00:00
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struct btrfs_ordered_sum;
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2007-03-16 20:20:31 +00:00
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2008-12-02 14:58:02 +00:00
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#define BTRFS_MAGIC "_BHRfS_M"
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2007-02-02 14:18:22 +00:00
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2009-02-12 19:09:45 +00:00
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#define BTRFS_MAX_LEVEL 8
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2008-03-24 19:01:56 +00:00
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Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
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#define BTRFS_COMPAT_EXTENT_TREE_V0
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2009-03-31 17:27:11 +00:00
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/*
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* files bigger than this get some pre-flushing when they are added
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* to the ordered operations list. That way we limit the total
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* work done by the commit
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*/
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#define BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT (8 * 1024 * 1024)
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2008-03-24 19:01:56 +00:00
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/* holds pointers to all of the tree roots */
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2007-03-27 10:33:00 +00:00
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#define BTRFS_ROOT_TREE_OBJECTID 1ULL
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2008-03-24 19:01:56 +00:00
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/* stores information about which extents are in use, and reference counts */
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2007-06-09 13:22:25 +00:00
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#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
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2008-03-24 19:01:56 +00:00
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/*
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* chunk tree stores translations from logical -> physical block numbering
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* the super block points to the chunk tree
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*/
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2008-03-24 19:02:07 +00:00
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#define BTRFS_CHUNK_TREE_OBJECTID 3ULL
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2008-03-24 19:01:56 +00:00
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/*
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* stores information about which areas of a given device are in use.
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* one per device. The tree of tree roots points to the device tree
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*/
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2008-03-24 19:02:07 +00:00
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#define BTRFS_DEV_TREE_OBJECTID 4ULL
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/* one per subvolume, storing files and directories */
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#define BTRFS_FS_TREE_OBJECTID 5ULL
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/* directory objectid inside the root tree */
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#define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL
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2008-03-24 19:01:56 +00:00
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Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
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/* holds checksums of all the data extents */
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#define BTRFS_CSUM_TREE_OBJECTID 7ULL
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2008-07-24 16:17:14 +00:00
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/* orhpan objectid for tracking unlinked/truncated files */
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#define BTRFS_ORPHAN_OBJECTID -5ULL
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2008-09-05 20:13:11 +00:00
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/* does write ahead logging to speed up fsyncs */
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#define BTRFS_TREE_LOG_OBJECTID -6ULL
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#define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL
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2008-09-26 14:04:53 +00:00
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/* for space balancing */
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#define BTRFS_TREE_RELOC_OBJECTID -8ULL
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#define BTRFS_DATA_RELOC_TREE_OBJECTID -9ULL
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Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
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/*
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* extent checksums all have this objectid
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* this allows them to share the logging tree
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* for fsyncs
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*/
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#define BTRFS_EXTENT_CSUM_OBJECTID -10ULL
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2008-09-23 17:14:14 +00:00
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/* dummy objectid represents multiple objectids */
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#define BTRFS_MULTIPLE_OBJECTIDS -255ULL
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2008-03-24 19:01:56 +00:00
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/*
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2008-09-05 20:43:53 +00:00
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* All files have objectids in this range.
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2008-03-24 19:01:56 +00:00
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*/
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2007-12-13 16:13:32 +00:00
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#define BTRFS_FIRST_FREE_OBJECTID 256ULL
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2008-09-05 20:43:53 +00:00
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#define BTRFS_LAST_FREE_OBJECTID -256ULL
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2008-04-15 19:41:47 +00:00
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#define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL
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2007-03-13 20:47:54 +00:00
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2008-03-24 19:01:56 +00:00
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/*
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* the device items go into the chunk tree. The key is in the form
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* [ 1 BTRFS_DEV_ITEM_KEY device_id ]
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*/
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#define BTRFS_DEV_ITEMS_OBJECTID 1ULL
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2009-09-21 19:56:00 +00:00
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#define BTRFS_BTREE_INODE_OBJECTID 1
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#define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2
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2007-03-22 16:13:20 +00:00
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/*
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* we can actually store much bigger names, but lets not confuse the rest
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* of linux
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*/
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#define BTRFS_NAME_LEN 255
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2007-03-29 19:15:27 +00:00
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/* 32 bytes in various csum fields */
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#define BTRFS_CSUM_SIZE 32
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2008-12-02 12:17:45 +00:00
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/* csum types */
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#define BTRFS_CSUM_TYPE_CRC32 0
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static int btrfs_csum_sizes[] = { 4, 0 };
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2007-05-10 16:36:17 +00:00
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/* four bytes for CRC32 */
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2007-12-12 19:38:19 +00:00
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#define BTRFS_EMPTY_DIR_SIZE 0
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2007-03-29 19:15:27 +00:00
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2007-06-08 02:13:21 +00:00
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#define BTRFS_FT_UNKNOWN 0
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#define BTRFS_FT_REG_FILE 1
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#define BTRFS_FT_DIR 2
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#define BTRFS_FT_CHRDEV 3
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#define BTRFS_FT_BLKDEV 4
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#define BTRFS_FT_FIFO 5
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#define BTRFS_FT_SOCK 6
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#define BTRFS_FT_SYMLINK 7
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2007-11-16 16:45:54 +00:00
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#define BTRFS_FT_XATTR 8
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#define BTRFS_FT_MAX 9
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2007-06-08 02:13:21 +00:00
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2007-02-26 15:40:21 +00:00
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/*
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2009-04-02 20:46:06 +00:00
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* The key defines the order in the tree, and so it also defines (optimal)
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* block layout.
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*
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* objectid corresponds to the inode number.
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*
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* type tells us things about the object, and is a kind of stream selector.
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* so for a given inode, keys with type of 1 might refer to the inode data,
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* type of 2 may point to file data in the btree and type == 3 may point to
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* extents.
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2007-02-26 15:40:21 +00:00
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*
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* offset is the starting byte offset for this key in the stream.
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2007-03-12 20:22:34 +00:00
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*
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* btrfs_disk_key is in disk byte order. struct btrfs_key is always
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* in cpu native order. Otherwise they are identical and their sizes
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* should be the same (ie both packed)
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2007-02-26 15:40:21 +00:00
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*/
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2007-03-12 20:22:34 +00:00
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struct btrfs_disk_key {
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__le64 objectid;
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2007-10-15 20:14:19 +00:00
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u8 type;
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2007-04-17 19:39:32 +00:00
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__le64 offset;
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2007-03-12 20:22:34 +00:00
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} __attribute__ ((__packed__));
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struct btrfs_key {
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2007-02-02 14:18:22 +00:00
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u64 objectid;
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2007-10-15 20:14:19 +00:00
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u8 type;
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2007-04-17 19:39:32 +00:00
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u64 offset;
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2007-02-02 14:18:22 +00:00
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} __attribute__ ((__packed__));
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2008-03-24 19:01:56 +00:00
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struct btrfs_mapping_tree {
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struct extent_map_tree map_tree;
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};
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2008-04-15 19:41:47 +00:00
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#define BTRFS_UUID_SIZE 16
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2008-03-24 19:01:56 +00:00
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struct btrfs_dev_item {
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/* the internal btrfs device id */
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__le64 devid;
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/* size of the device */
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__le64 total_bytes;
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/* bytes used */
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__le64 bytes_used;
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/* optimal io alignment for this device */
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__le32 io_align;
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/* optimal io width for this device */
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__le32 io_width;
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/* minimal io size for this device */
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__le32 sector_size;
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/* type and info about this device */
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__le64 type;
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2008-11-18 02:11:30 +00:00
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/* expected generation for this device */
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__le64 generation;
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2008-12-08 21:40:21 +00:00
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/*
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* starting byte of this partition on the device,
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2009-04-02 20:46:06 +00:00
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* to allow for stripe alignment in the future
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2008-12-08 21:40:21 +00:00
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*/
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__le64 start_offset;
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2008-04-15 19:41:47 +00:00
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/* grouping information for allocation decisions */
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__le32 dev_group;
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/* seek speed 0-100 where 100 is fastest */
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u8 seek_speed;
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/* bandwidth 0-100 where 100 is fastest */
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u8 bandwidth;
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2008-03-24 19:02:07 +00:00
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/* btrfs generated uuid for this device */
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2008-04-15 19:41:47 +00:00
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u8 uuid[BTRFS_UUID_SIZE];
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2008-11-18 02:11:30 +00:00
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/* uuid of FS who owns this device */
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u8 fsid[BTRFS_UUID_SIZE];
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2008-03-24 19:01:56 +00:00
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} __attribute__ ((__packed__));
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struct btrfs_stripe {
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__le64 devid;
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__le64 offset;
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2008-04-15 19:41:47 +00:00
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u8 dev_uuid[BTRFS_UUID_SIZE];
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2008-03-24 19:01:56 +00:00
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} __attribute__ ((__packed__));
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struct btrfs_chunk {
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2008-04-15 19:41:47 +00:00
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|
|
/* size of this chunk in bytes */
|
|
|
|
__le64 length;
|
|
|
|
|
|
|
|
/* objectid of the root referencing this chunk */
|
2008-03-24 19:01:56 +00:00
|
|
|
__le64 owner;
|
2008-04-15 19:41:47 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
__le64 stripe_len;
|
|
|
|
__le64 type;
|
|
|
|
|
|
|
|
/* optimal io alignment for this chunk */
|
|
|
|
__le32 io_align;
|
|
|
|
|
|
|
|
/* optimal io width for this chunk */
|
|
|
|
__le32 io_width;
|
|
|
|
|
|
|
|
/* minimal io size for this chunk */
|
|
|
|
__le32 sector_size;
|
|
|
|
|
|
|
|
/* 2^16 stripes is quite a lot, a second limit is the size of a single
|
|
|
|
* item in the btree
|
|
|
|
*/
|
|
|
|
__le16 num_stripes;
|
2008-04-16 14:49:51 +00:00
|
|
|
|
|
|
|
/* sub stripes only matter for raid10 */
|
|
|
|
__le16 sub_stripes;
|
2008-03-24 19:01:56 +00:00
|
|
|
struct btrfs_stripe stripe;
|
|
|
|
/* additional stripes go here */
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
|
|
|
static inline unsigned long btrfs_chunk_item_size(int num_stripes)
|
|
|
|
{
|
|
|
|
BUG_ON(num_stripes == 0);
|
|
|
|
return sizeof(struct btrfs_chunk) +
|
|
|
|
sizeof(struct btrfs_stripe) * (num_stripes - 1);
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
#define BTRFS_FSID_SIZE 16
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#define BTRFS_HEADER_FLAG_WRITTEN (1ULL << 0)
|
|
|
|
#define BTRFS_HEADER_FLAG_RELOC (1ULL << 1)
|
|
|
|
#define BTRFS_SUPER_FLAG_SEEDING (1ULL << 32)
|
|
|
|
#define BTRFS_SUPER_FLAG_METADUMP (1ULL << 33)
|
|
|
|
|
|
|
|
#define BTRFS_BACKREF_REV_MAX 256
|
|
|
|
#define BTRFS_BACKREF_REV_SHIFT 56
|
|
|
|
#define BTRFS_BACKREF_REV_MASK (((u64)BTRFS_BACKREF_REV_MAX - 1) << \
|
|
|
|
BTRFS_BACKREF_REV_SHIFT)
|
|
|
|
|
|
|
|
#define BTRFS_OLD_BACKREF_REV 0
|
|
|
|
#define BTRFS_MIXED_BACKREF_REV 1
|
2008-04-01 15:21:32 +00:00
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
|
|
|
* every tree block (leaf or node) starts with this header.
|
|
|
|
*/
|
2007-03-12 16:29:44 +00:00
|
|
|
struct btrfs_header {
|
2008-04-15 19:41:47 +00:00
|
|
|
/* these first four must match the super block */
|
2007-03-29 19:15:27 +00:00
|
|
|
u8 csum[BTRFS_CSUM_SIZE];
|
2007-10-15 20:14:19 +00:00
|
|
|
u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
|
2007-10-15 20:15:53 +00:00
|
|
|
__le64 bytenr; /* which block this node is supposed to live in */
|
2008-04-01 15:21:32 +00:00
|
|
|
__le64 flags;
|
2008-04-15 19:41:47 +00:00
|
|
|
|
|
|
|
/* allowed to be different from the super from here on down */
|
|
|
|
u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
|
2007-03-23 19:56:19 +00:00
|
|
|
__le64 generation;
|
2007-04-21 00:23:12 +00:00
|
|
|
__le64 owner;
|
2007-10-15 20:14:19 +00:00
|
|
|
__le32 nritems;
|
2007-03-27 13:06:38 +00:00
|
|
|
u8 level;
|
2007-02-02 14:18:22 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
#define BTRFS_NODEPTRS_PER_BLOCK(r) (((r)->nodesize - \
|
2009-01-06 02:25:51 +00:00
|
|
|
sizeof(struct btrfs_header)) / \
|
|
|
|
sizeof(struct btrfs_key_ptr))
|
2007-03-14 18:14:43 +00:00
|
|
|
#define __BTRFS_LEAF_DATA_SIZE(bs) ((bs) - sizeof(struct btrfs_header))
|
2007-10-15 20:14:19 +00:00
|
|
|
#define BTRFS_LEAF_DATA_SIZE(r) (__BTRFS_LEAF_DATA_SIZE(r->leafsize))
|
2007-04-19 17:37:44 +00:00
|
|
|
#define BTRFS_MAX_INLINE_DATA_SIZE(r) (BTRFS_LEAF_DATA_SIZE(r) - \
|
|
|
|
sizeof(struct btrfs_item) - \
|
|
|
|
sizeof(struct btrfs_file_extent_item))
|
2007-02-02 14:18:22 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* this is a very generous portion of the super block, giving us
|
|
|
|
* room to translate 14 chunks with 3 stripes each.
|
|
|
|
*/
|
|
|
|
#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
|
2008-04-18 14:29:49 +00:00
|
|
|
#define BTRFS_LABEL_SIZE 256
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
|
|
|
* the super block basically lists the main trees of the FS
|
|
|
|
* it currently lacks any block count etc etc
|
|
|
|
*/
|
2007-03-13 14:46:10 +00:00
|
|
|
struct btrfs_super_block {
|
2007-03-29 19:15:27 +00:00
|
|
|
u8 csum[BTRFS_CSUM_SIZE];
|
2008-04-01 15:21:32 +00:00
|
|
|
/* the first 4 fields must match struct btrfs_header */
|
2008-11-18 02:11:30 +00:00
|
|
|
u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
|
2007-10-15 20:15:53 +00:00
|
|
|
__le64 bytenr; /* this block number */
|
2008-04-01 15:21:32 +00:00
|
|
|
__le64 flags;
|
2008-04-15 19:41:47 +00:00
|
|
|
|
|
|
|
/* allowed to be different from the btrfs_header from here own down */
|
2007-03-13 20:47:54 +00:00
|
|
|
__le64 magic;
|
|
|
|
__le64 generation;
|
|
|
|
__le64 root;
|
2008-03-24 19:01:56 +00:00
|
|
|
__le64 chunk_root;
|
2008-09-05 20:13:11 +00:00
|
|
|
__le64 log_root;
|
2008-12-08 21:40:21 +00:00
|
|
|
|
|
|
|
/* this will help find the new super based on the log root */
|
|
|
|
__le64 log_root_transid;
|
2007-10-15 20:15:53 +00:00
|
|
|
__le64 total_bytes;
|
|
|
|
__le64 bytes_used;
|
2007-03-21 15:12:56 +00:00
|
|
|
__le64 root_dir_objectid;
|
2008-03-24 19:02:07 +00:00
|
|
|
__le64 num_devices;
|
2007-10-15 20:14:19 +00:00
|
|
|
__le32 sectorsize;
|
|
|
|
__le32 nodesize;
|
|
|
|
__le32 leafsize;
|
2007-11-30 16:30:34 +00:00
|
|
|
__le32 stripesize;
|
2008-03-24 19:01:56 +00:00
|
|
|
__le32 sys_chunk_array_size;
|
2008-10-29 18:49:05 +00:00
|
|
|
__le64 chunk_root_generation;
|
2008-12-02 11:36:08 +00:00
|
|
|
__le64 compat_flags;
|
|
|
|
__le64 compat_ro_flags;
|
|
|
|
__le64 incompat_flags;
|
2008-12-02 12:17:45 +00:00
|
|
|
__le16 csum_type;
|
2007-10-15 20:15:53 +00:00
|
|
|
u8 root_level;
|
2008-03-24 19:01:56 +00:00
|
|
|
u8 chunk_root_level;
|
2008-09-05 20:13:11 +00:00
|
|
|
u8 log_root_level;
|
2008-03-24 19:02:07 +00:00
|
|
|
struct btrfs_dev_item dev_item;
|
2008-12-08 21:40:21 +00:00
|
|
|
|
2008-04-18 14:29:49 +00:00
|
|
|
char label[BTRFS_LABEL_SIZE];
|
2008-12-08 21:40:21 +00:00
|
|
|
|
|
|
|
/* future expansion */
|
|
|
|
__le64 reserved[32];
|
2008-03-24 19:01:56 +00:00
|
|
|
u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
|
2007-02-21 22:04:57 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2008-12-02 11:36:08 +00:00
|
|
|
/*
|
|
|
|
* Compat flags that we support. If any incompat flags are set other than the
|
|
|
|
* ones specified below then we will fail to mount
|
|
|
|
*/
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#define BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF (1ULL << 0)
|
|
|
|
|
|
|
|
#define BTRFS_FEATURE_COMPAT_SUPP 0ULL
|
|
|
|
#define BTRFS_FEATURE_COMPAT_RO_SUPP 0ULL
|
|
|
|
#define BTRFS_FEATURE_INCOMPAT_SUPP \
|
|
|
|
BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF
|
2008-12-02 11:36:08 +00:00
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
2007-03-15 16:56:47 +00:00
|
|
|
* A leaf is full of items. offset and size tell us where to find
|
2007-02-26 15:40:21 +00:00
|
|
|
* the item in the leaf (relative to the start of the data area)
|
|
|
|
*/
|
2007-03-13 00:12:07 +00:00
|
|
|
struct btrfs_item {
|
2007-03-12 20:22:34 +00:00
|
|
|
struct btrfs_disk_key key;
|
2007-03-14 18:14:43 +00:00
|
|
|
__le32 offset;
|
2007-10-15 20:14:19 +00:00
|
|
|
__le32 size;
|
2007-02-02 14:18:22 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
|
|
|
* leaves have an item area and a data area:
|
|
|
|
* [item0, item1....itemN] [free space] [dataN...data1, data0]
|
|
|
|
*
|
|
|
|
* The data is separate from the items to get the keys closer together
|
|
|
|
* during searches.
|
|
|
|
*/
|
2007-03-13 14:46:10 +00:00
|
|
|
struct btrfs_leaf {
|
2007-03-12 16:29:44 +00:00
|
|
|
struct btrfs_header header;
|
2007-03-14 18:14:43 +00:00
|
|
|
struct btrfs_item items[];
|
2007-02-02 14:18:22 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
|
|
|
* all non-leaf blocks are nodes, they hold only keys and pointers to
|
|
|
|
* other blocks
|
|
|
|
*/
|
2007-03-14 18:14:43 +00:00
|
|
|
struct btrfs_key_ptr {
|
|
|
|
struct btrfs_disk_key key;
|
|
|
|
__le64 blockptr;
|
2007-12-11 14:25:06 +00:00
|
|
|
__le64 generation;
|
2007-03-14 18:14:43 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-03-13 14:46:10 +00:00
|
|
|
struct btrfs_node {
|
2007-03-12 16:29:44 +00:00
|
|
|
struct btrfs_header header;
|
2007-03-14 18:14:43 +00:00
|
|
|
struct btrfs_key_ptr ptrs[];
|
2007-02-02 14:18:22 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-02-26 15:40:21 +00:00
|
|
|
/*
|
2007-03-13 14:46:10 +00:00
|
|
|
* btrfs_paths remember the path taken from the root down to the leaf.
|
|
|
|
* level 0 is always the leaf, and nodes[1...BTRFS_MAX_LEVEL] will point
|
2007-02-26 15:40:21 +00:00
|
|
|
* to any other levels that are present.
|
|
|
|
*
|
|
|
|
* The slots array records the index of the item or block pointer
|
|
|
|
* used while walking the tree.
|
|
|
|
*/
|
2007-03-13 14:46:10 +00:00
|
|
|
struct btrfs_path {
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *nodes[BTRFS_MAX_LEVEL];
|
2007-03-13 14:46:10 +00:00
|
|
|
int slots[BTRFS_MAX_LEVEL];
|
2008-06-25 20:01:30 +00:00
|
|
|
/* if there is real range locking, this locks field will change */
|
|
|
|
int locks[BTRFS_MAX_LEVEL];
|
2007-08-07 19:52:22 +00:00
|
|
|
int reada;
|
2008-06-25 20:01:30 +00:00
|
|
|
/* keep some upper locks as we walk down */
|
2007-08-07 20:15:09 +00:00
|
|
|
int lowest_level;
|
2008-12-10 14:10:46 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* set by btrfs_split_item, tells search_slot to keep all locks
|
|
|
|
* and to force calls to keep space in the nodes
|
|
|
|
*/
|
2009-03-13 15:00:37 +00:00
|
|
|
unsigned int search_for_split:1;
|
|
|
|
unsigned int keep_locks:1;
|
|
|
|
unsigned int skip_locking:1;
|
|
|
|
unsigned int leave_spinning:1;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
unsigned int search_commit_root:1;
|
2007-02-02 14:18:22 +00:00
|
|
|
};
|
2007-02-24 11:24:44 +00:00
|
|
|
|
2007-03-15 16:56:47 +00:00
|
|
|
/*
|
|
|
|
* items in the extent btree are used to record the objectid of the
|
|
|
|
* owner of the block and the number of references
|
|
|
|
*/
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2007-03-15 16:56:47 +00:00
|
|
|
struct btrfs_extent_item {
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
__le64 refs;
|
|
|
|
__le64 generation;
|
|
|
|
__le64 flags;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
|
|
|
struct btrfs_extent_item_v0 {
|
2007-03-15 16:56:47 +00:00
|
|
|
__le32 refs;
|
2007-12-11 14:25:06 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
#define BTRFS_MAX_EXTENT_ITEM_SIZE(r) ((BTRFS_LEAF_DATA_SIZE(r) >> 4) - \
|
|
|
|
sizeof(struct btrfs_item))
|
|
|
|
|
|
|
|
#define BTRFS_EXTENT_FLAG_DATA (1ULL << 0)
|
|
|
|
#define BTRFS_EXTENT_FLAG_TREE_BLOCK (1ULL << 1)
|
|
|
|
|
|
|
|
/* following flags only apply to tree blocks */
|
|
|
|
|
|
|
|
/* use full backrefs for extent pointers in the block */
|
|
|
|
#define BTRFS_BLOCK_FLAG_FULL_BACKREF (1ULL << 8)
|
|
|
|
|
|
|
|
struct btrfs_tree_block_info {
|
|
|
|
struct btrfs_disk_key key;
|
|
|
|
u8 level;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
|
|
|
struct btrfs_extent_data_ref {
|
|
|
|
__le64 root;
|
|
|
|
__le64 objectid;
|
|
|
|
__le64 offset;
|
|
|
|
__le32 count;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
|
|
|
struct btrfs_shared_data_ref {
|
|
|
|
__le32 count;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
|
|
|
struct btrfs_extent_inline_ref {
|
|
|
|
u8 type;
|
2009-07-22 13:59:00 +00:00
|
|
|
__le64 offset;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
|
|
|
/* old style backrefs item */
|
|
|
|
struct btrfs_extent_ref_v0 {
|
2007-12-11 14:25:06 +00:00
|
|
|
__le64 root;
|
|
|
|
__le64 generation;
|
|
|
|
__le64 objectid;
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
__le32 count;
|
2007-03-15 16:56:47 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
/* dev extents record free space on individual devices. The owner
|
|
|
|
* field points back to the chunk allocation mapping tree that allocated
|
2008-04-15 19:41:47 +00:00
|
|
|
* the extent. The chunk tree uuid field is a way to double check the owner
|
2008-03-24 19:01:56 +00:00
|
|
|
*/
|
|
|
|
struct btrfs_dev_extent {
|
2008-04-15 19:41:47 +00:00
|
|
|
__le64 chunk_tree;
|
|
|
|
__le64 chunk_objectid;
|
|
|
|
__le64 chunk_offset;
|
2008-03-24 19:01:56 +00:00
|
|
|
__le64 length;
|
2008-04-15 19:41:47 +00:00
|
|
|
u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
|
2008-03-24 19:01:56 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-12-12 19:38:19 +00:00
|
|
|
struct btrfs_inode_ref {
|
2008-07-24 16:12:38 +00:00
|
|
|
__le64 index;
|
2007-12-12 19:38:19 +00:00
|
|
|
__le16 name_len;
|
|
|
|
/* name goes here */
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
struct btrfs_timespec {
|
2007-03-29 19:15:27 +00:00
|
|
|
__le64 sec;
|
2007-03-15 23:03:33 +00:00
|
|
|
__le32 nsec;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2009-01-21 15:49:16 +00:00
|
|
|
enum btrfs_compression_type {
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
BTRFS_COMPRESS_NONE = 0,
|
|
|
|
BTRFS_COMPRESS_ZLIB = 1,
|
|
|
|
BTRFS_COMPRESS_LAST = 2,
|
2009-01-21 15:49:16 +00:00
|
|
|
};
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
|
2007-03-15 23:03:33 +00:00
|
|
|
struct btrfs_inode_item {
|
2008-09-05 20:13:11 +00:00
|
|
|
/* nfs style generation number */
|
2007-03-15 23:03:33 +00:00
|
|
|
__le64 generation;
|
2008-09-05 20:13:11 +00:00
|
|
|
/* transid that last touched this inode */
|
|
|
|
__le64 transid;
|
2007-03-15 23:03:33 +00:00
|
|
|
__le64 size;
|
2008-10-09 15:46:29 +00:00
|
|
|
__le64 nbytes;
|
2007-04-30 19:25:45 +00:00
|
|
|
__le64 block_group;
|
2007-03-15 23:03:33 +00:00
|
|
|
__le32 nlink;
|
|
|
|
__le32 uid;
|
|
|
|
__le32 gid;
|
|
|
|
__le32 mode;
|
2008-03-24 19:01:56 +00:00
|
|
|
__le64 rdev;
|
2008-12-02 11:36:08 +00:00
|
|
|
__le64 flags;
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
|
2008-12-08 21:40:21 +00:00
|
|
|
/* modification sequence number for NFS */
|
|
|
|
__le64 sequence;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* a little future expansion, for more than this we can
|
|
|
|
* just grow the inode item and version it
|
|
|
|
*/
|
|
|
|
__le64 reserved[4];
|
2008-03-24 19:01:56 +00:00
|
|
|
struct btrfs_timespec atime;
|
|
|
|
struct btrfs_timespec ctime;
|
|
|
|
struct btrfs_timespec mtime;
|
|
|
|
struct btrfs_timespec otime;
|
2007-03-15 23:03:33 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2008-09-05 20:13:11 +00:00
|
|
|
struct btrfs_dir_log_item {
|
|
|
|
__le64 end;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-03-15 16:56:47 +00:00
|
|
|
struct btrfs_dir_item {
|
2007-04-06 19:37:36 +00:00
|
|
|
struct btrfs_disk_key location;
|
2008-09-05 20:13:11 +00:00
|
|
|
__le64 transid;
|
2007-11-16 16:45:54 +00:00
|
|
|
__le16 data_len;
|
2007-03-16 12:46:49 +00:00
|
|
|
__le16 name_len;
|
2007-03-15 16:56:47 +00:00
|
|
|
u8 type;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
|
|
|
struct btrfs_root_item {
|
2007-04-06 19:37:36 +00:00
|
|
|
struct btrfs_inode_item inode;
|
2008-10-29 18:49:05 +00:00
|
|
|
__le64 generation;
|
2007-04-06 19:37:36 +00:00
|
|
|
__le64 root_dirid;
|
2007-10-15 20:15:53 +00:00
|
|
|
__le64 bytenr;
|
|
|
|
__le64 byte_limit;
|
|
|
|
__le64 bytes_used;
|
2008-10-30 18:20:02 +00:00
|
|
|
__le64 last_snapshot;
|
2008-12-02 11:36:08 +00:00
|
|
|
__le64 flags;
|
2007-03-15 16:56:47 +00:00
|
|
|
__le32 refs;
|
2007-06-22 18:16:25 +00:00
|
|
|
struct btrfs_disk_key drop_progress;
|
|
|
|
u8 drop_level;
|
2007-10-15 20:15:53 +00:00
|
|
|
u8 level;
|
2007-03-20 18:38:32 +00:00
|
|
|
} __attribute__ ((__packed__));
|
2007-03-15 16:56:47 +00:00
|
|
|
|
2008-11-18 01:37:39 +00:00
|
|
|
/*
|
|
|
|
* this is used for both forward and backward root refs
|
|
|
|
*/
|
|
|
|
struct btrfs_root_ref {
|
|
|
|
__le64 dirid;
|
|
|
|
__le64 sequence;
|
|
|
|
__le16 name_len;
|
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2008-10-30 18:25:28 +00:00
|
|
|
#define BTRFS_FILE_EXTENT_INLINE 0
|
|
|
|
#define BTRFS_FILE_EXTENT_REG 1
|
|
|
|
#define BTRFS_FILE_EXTENT_PREALLOC 2
|
2007-04-19 17:37:44 +00:00
|
|
|
|
2007-03-20 18:38:32 +00:00
|
|
|
struct btrfs_file_extent_item {
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
/*
|
|
|
|
* transaction id that created this extent
|
|
|
|
*/
|
2007-03-27 13:16:29 +00:00
|
|
|
__le64 generation;
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
/*
|
|
|
|
* max number of bytes to hold this extent in ram
|
|
|
|
* when we split a compressed extent we can't know how big
|
|
|
|
* each of the resulting pieces will be. So, this is
|
|
|
|
* an upper limit on the size of the extent in ram instead of
|
|
|
|
* an exact limit.
|
|
|
|
*/
|
|
|
|
__le64 ram_bytes;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 32 bits for the various ways we might encode the data,
|
|
|
|
* including compression and encryption. If any of these
|
|
|
|
* are set to something a given disk format doesn't understand
|
|
|
|
* it is treated like an incompat flag for reading and writing,
|
|
|
|
* but not for stat.
|
|
|
|
*/
|
|
|
|
u8 compression;
|
|
|
|
u8 encryption;
|
|
|
|
__le16 other_encoding; /* spare for later use */
|
|
|
|
|
|
|
|
/* are we inline data or a real extent? */
|
2007-04-19 17:37:44 +00:00
|
|
|
u8 type;
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
|
2007-03-20 18:38:32 +00:00
|
|
|
/*
|
|
|
|
* disk space consumed by the extent, checksum blocks are included
|
|
|
|
* in these numbers
|
|
|
|
*/
|
2007-10-15 20:15:53 +00:00
|
|
|
__le64 disk_bytenr;
|
|
|
|
__le64 disk_num_bytes;
|
2007-03-20 18:38:32 +00:00
|
|
|
/*
|
2007-03-26 20:00:06 +00:00
|
|
|
* the logical offset in file blocks (no csums)
|
2007-03-20 18:38:32 +00:00
|
|
|
* this extent record is for. This allows a file extent to point
|
|
|
|
* into the middle of an existing extent on disk, sharing it
|
|
|
|
* between two snapshots (useful if some bytes in the middle of the
|
|
|
|
* extent have changed
|
|
|
|
*/
|
|
|
|
__le64 offset;
|
|
|
|
/*
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
* the logical number of file blocks (no csums included). This
|
|
|
|
* always reflects the size uncompressed and without encoding.
|
2007-03-20 18:38:32 +00:00
|
|
|
*/
|
2007-10-15 20:15:53 +00:00
|
|
|
__le64 num_bytes;
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
|
2007-03-20 18:38:32 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2007-03-29 19:15:27 +00:00
|
|
|
struct btrfs_csum_item {
|
2007-05-10 16:36:17 +00:00
|
|
|
u8 csum;
|
2007-03-29 19:15:27 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
/* different types of block groups (and chunks) */
|
|
|
|
#define BTRFS_BLOCK_GROUP_DATA (1 << 0)
|
|
|
|
#define BTRFS_BLOCK_GROUP_SYSTEM (1 << 1)
|
|
|
|
#define BTRFS_BLOCK_GROUP_METADATA (1 << 2)
|
2008-03-25 20:50:33 +00:00
|
|
|
#define BTRFS_BLOCK_GROUP_RAID0 (1 << 3)
|
2008-04-03 20:29:03 +00:00
|
|
|
#define BTRFS_BLOCK_GROUP_RAID1 (1 << 4)
|
2008-04-03 20:29:03 +00:00
|
|
|
#define BTRFS_BLOCK_GROUP_DUP (1 << 5)
|
2008-04-16 14:49:51 +00:00
|
|
|
#define BTRFS_BLOCK_GROUP_RAID10 (1 << 6)
|
2007-05-29 20:52:18 +00:00
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
struct btrfs_block_group_item {
|
|
|
|
__le64 used;
|
2008-03-24 19:01:56 +00:00
|
|
|
__le64 chunk_objectid;
|
|
|
|
__le64 flags;
|
2007-04-26 20:46:15 +00:00
|
|
|
} __attribute__ ((__packed__));
|
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
struct btrfs_space_info {
|
|
|
|
u64 flags;
|
2009-02-20 16:00:09 +00:00
|
|
|
|
|
|
|
u64 total_bytes; /* total bytes in the space */
|
|
|
|
u64 bytes_used; /* total bytes used on disk */
|
|
|
|
u64 bytes_pinned; /* total bytes pinned, will be freed when the
|
|
|
|
transaction finishes */
|
|
|
|
u64 bytes_reserved; /* total bytes the allocator has reserved for
|
|
|
|
current allocations */
|
|
|
|
u64 bytes_readonly; /* total bytes that are read only */
|
2009-09-11 20:11:20 +00:00
|
|
|
u64 bytes_super; /* total bytes reserved for the super blocks */
|
2009-09-11 20:12:44 +00:00
|
|
|
u64 bytes_root; /* the number of bytes needed to commit a
|
|
|
|
transaction */
|
2009-02-20 16:00:09 +00:00
|
|
|
u64 bytes_may_use; /* number of bytes that may be used for
|
2009-09-11 20:12:44 +00:00
|
|
|
delalloc/allocations */
|
|
|
|
u64 bytes_delalloc; /* number of bytes currently reserved for
|
|
|
|
delayed allocation */
|
2009-02-20 16:00:09 +00:00
|
|
|
|
|
|
|
int full; /* indicates that we cannot allocate any more
|
|
|
|
chunks for this space */
|
|
|
|
int force_alloc; /* set if we need to force a chunk alloc for
|
|
|
|
this space */
|
2009-09-11 20:12:44 +00:00
|
|
|
int force_delalloc; /* make people start doing filemap_flush until
|
|
|
|
we're under a threshold */
|
2009-02-20 16:00:09 +00:00
|
|
|
|
2008-03-24 19:01:59 +00:00
|
|
|
struct list_head list;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
2009-10-08 00:44:34 +00:00
|
|
|
/* for controlling how we free up space for allocations */
|
|
|
|
wait_queue_head_t allocate_wait;
|
|
|
|
wait_queue_head_t flush_wait;
|
|
|
|
int allocating_chunk;
|
|
|
|
int flushing;
|
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
/* for block groups in our same type */
|
|
|
|
struct list_head block_groups;
|
|
|
|
spinlock_t lock;
|
Btrfs: fix enospc when there is plenty of space
So there is an odd case where we can possibly return -ENOSPC when there is in
fact space to be had. It only happens with Metadata writes, and happens _very_
infrequently. What has to happen is we have to allocate have allocated out of
the first logical byte on the disk, which would set last_alloc to
first_logical_byte(root, 0), so search_start == orig_search_start. We then
need to allocate for normal metadata, so BTRFS_BLOCK_GROUP_METADATA |
BTRFS_BLOCK_GROUP_DUP. We will do a block lookup for the given search_start,
block_group_bits() won't match and we'll go to choose another block group.
However because search_start matches orig_search_start we go to see if we can
allocate a chunk.
If we are in the situation that we cannot allocate a chunk, we fail and ENOSPC.
This is kind of a big flaw of the way find_free_extent works, as it along with
find_free_space loop through _all_ of the block groups, not just the ones that
we want to allocate out of. This patch completely kills find_free_space and
rolls it into find_free_extent. I've introduced a sort of state machine into
this, which will make it easier to get cache miss information out of the
allocator, and will work well with my locking changes.
The basic flow is this: We have the variable loop which is 0, meaning we are
in the hint phase. We lookup the block group for the hint, and lookup the
space_info for what we want to allocate out of. If the block group we were
pointed at by the hint either isn't of the correct type, or just doesn't have
the space we need, we set head to space_info->block_groups, so we start at the
beginning of the block groups for this particular space info, and loop through.
This is also where we add the empty_cluster to total_needed. At this point
loop is set to 1 and we just loop through all of the block groups for this
particular space_info looking for the space we need, just as find_free_space
would have done, except we only hit the block groups we want and not _all_ of
the block groups. If we come full circle we see if we can allocate a chunk.
If we cannot of course we exit with -ENOSPC and we are good. If not we start
over at space_info->block_groups and loop through again, with loop == 2. If we
come full circle and haven't found what we need then we exit with -ENOSPC.
I've been running this for a couple of days now and it seems stable, and I
haven't yet hit a -ENOSPC when there was plenty of space left.
Also I've made a groups_sem to handle the group list for the space_info. This
is part of my locking changes, but is relatively safe and seems better than
holding the space_info spinlock over that entire search time. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
2008-10-29 18:49:05 +00:00
|
|
|
struct rw_semaphore groups_sem;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
atomic_t caching_threads;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
};
|
|
|
|
|
2009-04-03 13:47:43 +00:00
|
|
|
/*
|
|
|
|
* free clusters are used to claim free space in relatively large chunks,
|
|
|
|
* allowing us to do less seeky writes. They are used for all metadata
|
|
|
|
* allocations and data allocations in ssd mode.
|
|
|
|
*/
|
|
|
|
struct btrfs_free_cluster {
|
|
|
|
spinlock_t lock;
|
|
|
|
spinlock_t refill_lock;
|
|
|
|
struct rb_root root;
|
|
|
|
|
|
|
|
/* largest extent in this cluster */
|
|
|
|
u64 max_size;
|
|
|
|
|
|
|
|
/* first extent starting offset */
|
|
|
|
u64 window_start;
|
|
|
|
|
Btrfs: use hybrid extents+bitmap rb tree for free space
Currently btrfs has a problem where it can use a ridiculous amount of RAM simply
tracking free space. As free space gets fragmented, we end up with thousands of
entries on an rb-tree per block group, which usually spans 1 gig of area. Since
we currently don't ever flush free space cache back to disk this gets to be a
bit unweildly on large fs's with lots of fragmentation.
This patch solves this problem by using PAGE_SIZE bitmaps for parts of the free
space cache. Initially we calculate a threshold of extent entries we can
handle, which is however many extent entries we can cram into 16k of ram. The
maximum amount of RAM that should ever be used to track 1 gigabyte of diskspace
will be 32k of RAM, which scales much better than we did before.
Once we pass the extent threshold, we start adding bitmaps and using those
instead for tracking the free space. This patch also makes it so that any free
space thats less than 4 * sectorsize we go ahead and put into a bitmap. This is
nice since we try and allocate out of the front of a block group, so if the
front of a block group is heavily fragmented and then has a huge chunk of free
space at the end, we go ahead and add the fragmented areas to bitmaps and use a
normal extent entry to track the big chunk at the back of the block group.
I've also taken the opportunity to revamp how we search for free space.
Previously we indexed free space via an offset indexed rb tree and a bytes
indexed rb tree. I've dropped the bytes indexed rb tree and use only the offset
indexed rb tree. This cuts the number of tree operations we were doing
previously down by half, and gives us a little bit of a better allocation
pattern since we will always start from a specific offset and search forward
from there, instead of searching for the size we need and try and get it as
close as possible to the offset we want.
I've given this a healthy amount of testing pre-new format stuff, as well as
post-new format stuff. I've booted up my fedora box which is installed on btrfs
with this patch and ran with it for a few days without issues. I've not seen
any performance regressions in any of my tests.
Since the last patch Yan Zheng fixed a problem where we could have overlapping
entries, so updating their offset inline would cause problems. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
/* if this cluster simply points at a bitmap in the block group */
|
|
|
|
bool points_to_bitmap;
|
|
|
|
|
2009-04-03 13:47:43 +00:00
|
|
|
struct btrfs_block_group_cache *block_group;
|
|
|
|
/*
|
|
|
|
* when a cluster is allocated from a block group, we put the
|
|
|
|
* cluster onto a list in the block group so that it can
|
|
|
|
* be freed before the block group is freed.
|
|
|
|
*/
|
|
|
|
struct list_head block_group_list;
|
2008-03-24 19:01:59 +00:00
|
|
|
};
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
enum btrfs_caching_type {
|
|
|
|
BTRFS_CACHE_NO = 0,
|
|
|
|
BTRFS_CACHE_STARTED = 1,
|
|
|
|
BTRFS_CACHE_FINISHED = 2,
|
|
|
|
};
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_caching_control {
|
|
|
|
struct list_head list;
|
|
|
|
struct mutex mutex;
|
|
|
|
wait_queue_head_t wait;
|
|
|
|
struct btrfs_block_group_cache *block_group;
|
|
|
|
u64 progress;
|
|
|
|
atomic_t count;
|
|
|
|
};
|
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
struct btrfs_block_group_cache {
|
|
|
|
struct btrfs_key key;
|
|
|
|
struct btrfs_block_group_item item;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
struct btrfs_fs_info *fs_info;
|
2008-07-23 03:06:41 +00:00
|
|
|
spinlock_t lock;
|
2007-11-16 19:57:08 +00:00
|
|
|
u64 pinned;
|
2008-09-26 14:05:48 +00:00
|
|
|
u64 reserved;
|
2009-09-11 20:11:20 +00:00
|
|
|
u64 bytes_super;
|
2008-03-24 19:01:56 +00:00
|
|
|
u64 flags;
|
Btrfs: use hybrid extents+bitmap rb tree for free space
Currently btrfs has a problem where it can use a ridiculous amount of RAM simply
tracking free space. As free space gets fragmented, we end up with thousands of
entries on an rb-tree per block group, which usually spans 1 gig of area. Since
we currently don't ever flush free space cache back to disk this gets to be a
bit unweildly on large fs's with lots of fragmentation.
This patch solves this problem by using PAGE_SIZE bitmaps for parts of the free
space cache. Initially we calculate a threshold of extent entries we can
handle, which is however many extent entries we can cram into 16k of ram. The
maximum amount of RAM that should ever be used to track 1 gigabyte of diskspace
will be 32k of RAM, which scales much better than we did before.
Once we pass the extent threshold, we start adding bitmaps and using those
instead for tracking the free space. This patch also makes it so that any free
space thats less than 4 * sectorsize we go ahead and put into a bitmap. This is
nice since we try and allocate out of the front of a block group, so if the
front of a block group is heavily fragmented and then has a huge chunk of free
space at the end, we go ahead and add the fragmented areas to bitmaps and use a
normal extent entry to track the big chunk at the back of the block group.
I've also taken the opportunity to revamp how we search for free space.
Previously we indexed free space via an offset indexed rb tree and a bytes
indexed rb tree. I've dropped the bytes indexed rb tree and use only the offset
indexed rb tree. This cuts the number of tree operations we were doing
previously down by half, and gives us a little bit of a better allocation
pattern since we will always start from a specific offset and search forward
from there, instead of searching for the size we need and try and get it as
close as possible to the offset we want.
I've given this a healthy amount of testing pre-new format stuff, as well as
post-new format stuff. I've booted up my fedora box which is installed on btrfs
with this patch and ran with it for a few days without issues. I've not seen
any performance regressions in any of my tests.
Since the last patch Yan Zheng fixed a problem where we could have overlapping
entries, so updating their offset inline would cause problems. Thanks,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
u64 sectorsize;
|
|
|
|
int extents_thresh;
|
|
|
|
int free_extents;
|
|
|
|
int total_bitmaps;
|
2008-04-25 20:53:30 +00:00
|
|
|
int ro;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
int dirty;
|
|
|
|
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
/* cache tracking stuff */
|
|
|
|
int cached;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_caching_control *caching_ctl;
|
|
|
|
u64 last_byte_to_unpin;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct btrfs_space_info *space_info;
|
|
|
|
|
|
|
|
/* free space cache stuff */
|
2009-04-03 14:14:18 +00:00
|
|
|
spinlock_t tree_lock;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
struct rb_root free_space_offset;
|
Btrfs: async block group caching
This patch moves the caching of the block group off to a kthread in order to
allow people to allocate sooner. Instead of blocking up behind the caching
mutex, we instead kick of the caching kthread, and then attempt to make an
allocation. If we cannot, we wait on the block groups caching waitqueue, which
the caching kthread will wake the waiting threads up everytime it finds 2 meg
worth of space, and then again when its finished caching. This is how I tested
the speedup from this
mkfs the disk
mount the disk
fill the disk up with fs_mark
unmount the disk
mount the disk
time touch /mnt/foo
Without my changes this took 11 seconds on my box, with these changes it now
takes 1 second.
Another change thats been put in place is we lock the super mirror's in the
pinned extent map in order to keep us from adding that stuff as free space when
caching the block group. This doesn't really change anything else as far as the
pinned extent map is concerned, since for actual pinned extents we use
EXTENT_DIRTY, but it does mean that when we unmount we have to go in and unlock
those extents to keep from leaking memory.
I've also added a check where when we are reading block groups from disk, if the
amount of space used == the size of the block group, we go ahead and mark the
block group as cached. This drastically reduces the amount of time it takes to
cache the block groups. Using the same test as above, except doing a dd to a
file and then unmounting, it used to take 33 seconds to umount, now it takes 3
seconds.
This version uses the commit_root in the caching kthread, and then keeps track
of how many async caching threads are running at any given time so if one of the
async threads is still running as we cross transactions we can wait until its
finished before handling the pinned extents. Thank you,
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-14 01:29:25 +00:00
|
|
|
u64 free_space;
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
|
|
|
/* block group cache stuff */
|
|
|
|
struct rb_node cache_node;
|
|
|
|
|
|
|
|
/* for block groups in the same raid type */
|
|
|
|
struct list_head list;
|
2008-12-11 21:30:39 +00:00
|
|
|
|
|
|
|
/* usage count */
|
|
|
|
atomic_t count;
|
2009-04-03 13:47:43 +00:00
|
|
|
|
|
|
|
/* List of struct btrfs_free_clusters for this block group.
|
|
|
|
* Today it will only have one thing on it, but that may change
|
|
|
|
*/
|
|
|
|
struct list_head cluster_list;
|
2007-04-26 20:46:15 +00:00
|
|
|
};
|
2008-03-24 19:01:56 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct reloc_control;
|
2008-03-24 19:01:56 +00:00
|
|
|
struct btrfs_device;
|
2008-03-24 19:02:07 +00:00
|
|
|
struct btrfs_fs_devices;
|
2007-03-20 18:38:32 +00:00
|
|
|
struct btrfs_fs_info {
|
2007-10-15 20:14:19 +00:00
|
|
|
u8 fsid[BTRFS_FSID_SIZE];
|
2008-04-15 19:41:47 +00:00
|
|
|
u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
|
2007-03-15 16:56:47 +00:00
|
|
|
struct btrfs_root *extent_root;
|
|
|
|
struct btrfs_root *tree_root;
|
2008-03-24 19:01:56 +00:00
|
|
|
struct btrfs_root *chunk_root;
|
|
|
|
struct btrfs_root *dev_root;
|
2008-11-18 02:02:50 +00:00
|
|
|
struct btrfs_root *fs_root;
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
struct btrfs_root *csum_root;
|
2008-09-05 20:13:11 +00:00
|
|
|
|
|
|
|
/* the log root tree is a directory of all the other log roots */
|
|
|
|
struct btrfs_root *log_root_tree;
|
2009-09-21 19:56:00 +00:00
|
|
|
|
|
|
|
spinlock_t fs_roots_radix_lock;
|
2007-04-09 14:42:37 +00:00
|
|
|
struct radix_tree_root fs_roots_radix;
|
2007-10-15 20:15:26 +00:00
|
|
|
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
/* block group cache stuff */
|
|
|
|
spinlock_t block_group_cache_lock;
|
|
|
|
struct rb_root block_group_cache_tree;
|
|
|
|
|
2009-09-11 20:11:19 +00:00
|
|
|
struct extent_io_tree freed_extents[2];
|
|
|
|
struct extent_io_tree *pinned_extents;
|
2007-10-15 20:15:26 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
/* logical->physical extent mapping */
|
|
|
|
struct btrfs_mapping_tree mapping_tree;
|
|
|
|
|
2007-03-20 19:57:25 +00:00
|
|
|
u64 generation;
|
2007-08-10 20:22:09 +00:00
|
|
|
u64 last_trans_committed;
|
2009-03-24 14:24:20 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* this is updated to the current trans every time a full commit
|
|
|
|
* is required instead of the faster short fsync log commits
|
|
|
|
*/
|
|
|
|
u64 last_trans_log_full_commit;
|
2008-08-04 14:41:27 +00:00
|
|
|
u64 open_ioctl_trans;
|
2007-12-14 20:30:32 +00:00
|
|
|
unsigned long mount_opt;
|
2007-12-18 01:14:04 +00:00
|
|
|
u64 max_extent;
|
2008-01-29 21:03:38 +00:00
|
|
|
u64 max_inline;
|
2008-01-02 15:01:11 +00:00
|
|
|
u64 alloc_start;
|
2007-03-22 19:59:16 +00:00
|
|
|
struct btrfs_transaction *running_transaction;
|
2008-07-17 16:53:50 +00:00
|
|
|
wait_queue_head_t transaction_throttle;
|
2008-07-17 16:54:14 +00:00
|
|
|
wait_queue_head_t transaction_wait;
|
2008-11-07 03:02:51 +00:00
|
|
|
wait_queue_head_t async_submit_wait;
|
2008-09-05 20:13:11 +00:00
|
|
|
|
2007-06-26 14:06:50 +00:00
|
|
|
struct btrfs_super_block super_copy;
|
2008-05-07 15:43:44 +00:00
|
|
|
struct btrfs_super_block super_for_commit;
|
2008-03-24 19:01:56 +00:00
|
|
|
struct block_device *__bdev;
|
2007-03-22 16:13:20 +00:00
|
|
|
struct super_block *sb;
|
2007-03-28 17:57:48 +00:00
|
|
|
struct inode *btree_inode;
|
2008-03-26 14:28:07 +00:00
|
|
|
struct backing_dev_info bdi;
|
2007-03-22 19:59:16 +00:00
|
|
|
struct mutex trans_mutex;
|
2008-09-05 20:13:11 +00:00
|
|
|
struct mutex tree_log_mutex;
|
2008-06-25 20:01:31 +00:00
|
|
|
struct mutex transaction_kthread_mutex;
|
|
|
|
struct mutex cleaner_mutex;
|
2008-06-25 20:01:30 +00:00
|
|
|
struct mutex chunk_mutex;
|
2008-07-08 18:19:17 +00:00
|
|
|
struct mutex volume_mutex;
|
2009-03-31 17:27:11 +00:00
|
|
|
/*
|
|
|
|
* this protects the ordered operations list only while we are
|
|
|
|
* processing all of the entries on it. This way we make
|
|
|
|
* sure the commit code doesn't find the list temporarily empty
|
|
|
|
* because another function happens to be doing non-waiting preflush
|
|
|
|
* before jumping into the main commit.
|
|
|
|
*/
|
|
|
|
struct mutex ordered_operations_mutex;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct rw_semaphore extent_commit_sem;
|
2009-03-31 17:27:11 +00:00
|
|
|
|
2009-09-21 20:00:26 +00:00
|
|
|
struct rw_semaphore subvol_sem;
|
|
|
|
|
|
|
|
struct srcu_struct subvol_srcu;
|
|
|
|
|
2007-04-20 01:01:03 +00:00
|
|
|
struct list_head trans_list;
|
2007-10-15 20:19:22 +00:00
|
|
|
struct list_head hashers;
|
2007-06-08 22:11:48 +00:00
|
|
|
struct list_head dead_roots;
|
2009-09-11 20:11:19 +00:00
|
|
|
struct list_head caching_block_groups;
|
2008-09-05 20:13:11 +00:00
|
|
|
|
2008-05-15 20:15:45 +00:00
|
|
|
atomic_t nr_async_submits;
|
2008-09-29 15:19:10 +00:00
|
|
|
atomic_t async_submit_draining;
|
2008-08-15 19:34:15 +00:00
|
|
|
atomic_t nr_async_bios;
|
2008-11-07 03:02:51 +00:00
|
|
|
atomic_t async_delalloc_pages;
|
2008-04-09 20:28:12 +00:00
|
|
|
|
2008-07-24 15:57:52 +00:00
|
|
|
/*
|
|
|
|
* this is used by the balancing code to wait for all the pending
|
|
|
|
* ordered extents
|
|
|
|
*/
|
|
|
|
spinlock_t ordered_extent_lock;
|
2009-03-31 17:27:11 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* all of the data=ordered extents pending writeback
|
|
|
|
* these can span multiple transactions and basically include
|
|
|
|
* every dirty data page that isn't from nodatacow
|
|
|
|
*/
|
2008-07-24 15:57:52 +00:00
|
|
|
struct list_head ordered_extents;
|
2009-03-31 17:27:11 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* all of the inodes that have delalloc bytes. It is possible for
|
|
|
|
* this list to be empty even when there is still dirty data=ordered
|
|
|
|
* extents waiting to finish IO.
|
|
|
|
*/
|
2008-08-05 03:17:27 +00:00
|
|
|
struct list_head delalloc_inodes;
|
2008-07-24 15:57:52 +00:00
|
|
|
|
2009-03-31 17:27:11 +00:00
|
|
|
/*
|
|
|
|
* special rename and truncate targets that must be on disk before
|
|
|
|
* we're allowed to commit. This is basically the ext3 style
|
|
|
|
* data=ordered list.
|
|
|
|
*/
|
|
|
|
struct list_head ordered_operations;
|
|
|
|
|
2008-06-11 20:50:36 +00:00
|
|
|
/*
|
|
|
|
* there is a pool of worker threads for checksumming during writes
|
|
|
|
* and a pool for checksumming after reads. This is because readers
|
|
|
|
* can run with FS locks held, and the writers may be waiting for
|
|
|
|
* those locks. We don't want ordering in the pending list to cause
|
|
|
|
* deadlocks, and so the two are serviced separately.
|
2008-06-12 18:46:17 +00:00
|
|
|
*
|
|
|
|
* A third pool does submit_bio to avoid deadlocking with the other
|
|
|
|
* two
|
2008-06-11 20:50:36 +00:00
|
|
|
*/
|
2009-10-02 23:11:56 +00:00
|
|
|
struct btrfs_workers generic_worker;
|
2008-06-11 20:50:36 +00:00
|
|
|
struct btrfs_workers workers;
|
2008-11-07 03:02:51 +00:00
|
|
|
struct btrfs_workers delalloc_workers;
|
2008-06-11 20:50:36 +00:00
|
|
|
struct btrfs_workers endio_workers;
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
struct btrfs_workers endio_meta_workers;
|
2008-12-17 19:51:42 +00:00
|
|
|
struct btrfs_workers endio_meta_write_workers;
|
2008-07-17 16:53:50 +00:00
|
|
|
struct btrfs_workers endio_write_workers;
|
2008-06-12 18:46:17 +00:00
|
|
|
struct btrfs_workers submit_workers;
|
2009-10-08 00:44:34 +00:00
|
|
|
struct btrfs_workers enospc_workers;
|
2008-07-17 16:53:51 +00:00
|
|
|
/*
|
|
|
|
* fixup workers take dirty pages that didn't properly go through
|
|
|
|
* the cow mechanism and make them safe to write. It happens
|
|
|
|
* for the sys_munmap function call path
|
|
|
|
*/
|
|
|
|
struct btrfs_workers fixup_workers;
|
2008-06-25 20:01:31 +00:00
|
|
|
struct task_struct *transaction_kthread;
|
|
|
|
struct task_struct *cleaner_kthread;
|
2008-06-12 01:47:56 +00:00
|
|
|
int thread_pool_size;
|
2008-06-11 20:50:36 +00:00
|
|
|
|
2007-08-29 19:47:34 +00:00
|
|
|
struct kobject super_kobj;
|
|
|
|
struct completion kobj_unregister;
|
2007-04-20 17:16:02 +00:00
|
|
|
int do_barriers;
|
2007-06-08 22:11:48 +00:00
|
|
|
int closing;
|
2008-09-05 20:13:11 +00:00
|
|
|
int log_root_recovering;
|
2007-03-20 18:38:32 +00:00
|
|
|
|
2007-11-16 19:57:08 +00:00
|
|
|
u64 total_pinned;
|
2009-03-13 15:00:37 +00:00
|
|
|
|
|
|
|
/* protected by the delalloc lock, used to keep from writing
|
|
|
|
* metadata until there is a nice batch
|
|
|
|
*/
|
|
|
|
u64 dirty_metadata_bytes;
|
2008-03-24 19:01:56 +00:00
|
|
|
struct list_head dirty_cowonly_roots;
|
|
|
|
|
2008-03-24 19:02:07 +00:00
|
|
|
struct btrfs_fs_devices *fs_devices;
|
2009-03-10 16:39:20 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* the space_info list is almost entirely read only. It only changes
|
|
|
|
* when we add a new raid type to the FS, and that happens
|
|
|
|
* very rarely. RCU is used to protect it.
|
|
|
|
*/
|
2008-03-24 19:01:59 +00:00
|
|
|
struct list_head space_info;
|
2009-03-10 16:39:20 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct reloc_control *reloc_ctl;
|
|
|
|
|
2007-12-21 21:27:21 +00:00
|
|
|
spinlock_t delalloc_lock;
|
2008-01-15 13:40:48 +00:00
|
|
|
spinlock_t new_trans_lock;
|
2007-12-21 21:27:21 +00:00
|
|
|
u64 delalloc_bytes;
|
2009-04-03 13:47:43 +00:00
|
|
|
|
|
|
|
/* data_alloc_cluster is only used in ssd mode */
|
|
|
|
struct btrfs_free_cluster data_alloc_cluster;
|
|
|
|
|
|
|
|
/* all metadata allocations go through this cluster */
|
|
|
|
struct btrfs_free_cluster meta_alloc_cluster;
|
2008-04-04 19:40:00 +00:00
|
|
|
|
2008-07-28 19:32:19 +00:00
|
|
|
spinlock_t ref_cache_lock;
|
|
|
|
u64 total_ref_cache_size;
|
|
|
|
|
2008-04-04 19:40:00 +00:00
|
|
|
u64 avail_data_alloc_bits;
|
|
|
|
u64 avail_metadata_alloc_bits;
|
|
|
|
u64 avail_system_alloc_bits;
|
|
|
|
u64 data_alloc_profile;
|
|
|
|
u64 metadata_alloc_profile;
|
|
|
|
u64 system_alloc_profile;
|
2008-04-28 19:29:42 +00:00
|
|
|
|
2009-04-21 21:40:57 +00:00
|
|
|
unsigned data_chunk_allocations;
|
|
|
|
unsigned metadata_ratio;
|
|
|
|
|
2008-04-28 19:29:42 +00:00
|
|
|
void *bdev_holder;
|
2007-11-16 19:57:08 +00:00
|
|
|
};
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2007-03-20 18:38:32 +00:00
|
|
|
/*
|
|
|
|
* in ram representation of the tree. extent_root is used for all allocations
|
2007-04-25 19:52:25 +00:00
|
|
|
* and for the extent tree extent_root root.
|
2007-03-20 18:38:32 +00:00
|
|
|
*/
|
|
|
|
struct btrfs_root {
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *node;
|
2008-06-25 20:01:30 +00:00
|
|
|
|
|
|
|
/* the node lock is held while changing the node pointer */
|
|
|
|
spinlock_t node_lock;
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *commit_root;
|
2008-09-05 20:13:11 +00:00
|
|
|
struct btrfs_root *log_root;
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
struct btrfs_root *reloc_root;
|
2008-07-28 19:32:19 +00:00
|
|
|
|
2007-03-15 16:56:47 +00:00
|
|
|
struct btrfs_root_item root_item;
|
|
|
|
struct btrfs_key root_key;
|
2007-03-20 18:38:32 +00:00
|
|
|
struct btrfs_fs_info *fs_info;
|
2008-09-11 20:17:57 +00:00
|
|
|
struct extent_io_tree dirty_log_pages;
|
|
|
|
|
2007-08-29 19:47:34 +00:00
|
|
|
struct kobject root_kobj;
|
|
|
|
struct completion kobj_unregister;
|
2008-06-25 20:01:30 +00:00
|
|
|
struct mutex objectid_mutex;
|
2009-01-21 17:54:03 +00:00
|
|
|
|
2008-09-05 20:13:11 +00:00
|
|
|
struct mutex log_mutex;
|
2009-01-21 17:54:03 +00:00
|
|
|
wait_queue_head_t log_writer_wait;
|
|
|
|
wait_queue_head_t log_commit_wait[2];
|
|
|
|
atomic_t log_writers;
|
|
|
|
atomic_t log_commit[2];
|
|
|
|
unsigned long log_transid;
|
2009-10-13 17:21:08 +00:00
|
|
|
unsigned long last_log_commit;
|
2009-01-21 17:54:03 +00:00
|
|
|
unsigned long log_batch;
|
2009-10-08 19:30:04 +00:00
|
|
|
pid_t log_start_pid;
|
|
|
|
bool log_multiple_pids;
|
2008-08-05 03:17:27 +00:00
|
|
|
|
2007-04-09 14:42:37 +00:00
|
|
|
u64 objectid;
|
|
|
|
u64 last_trans;
|
2007-10-15 20:14:19 +00:00
|
|
|
|
|
|
|
/* data allocations are done in sectorsize units */
|
|
|
|
u32 sectorsize;
|
|
|
|
|
|
|
|
/* node allocations are done in nodesize units */
|
|
|
|
u32 nodesize;
|
|
|
|
|
|
|
|
/* leaf allocations are done in leafsize units */
|
|
|
|
u32 leafsize;
|
|
|
|
|
2007-11-30 16:30:34 +00:00
|
|
|
u32 stripesize;
|
|
|
|
|
2007-03-20 18:38:32 +00:00
|
|
|
u32 type;
|
2009-09-21 19:56:00 +00:00
|
|
|
|
|
|
|
u64 highest_objectid;
|
2007-08-07 19:52:19 +00:00
|
|
|
int ref_cows;
|
2008-03-24 19:01:56 +00:00
|
|
|
int track_dirty;
|
2009-09-21 19:56:00 +00:00
|
|
|
int in_radix;
|
|
|
|
|
2008-06-25 20:01:31 +00:00
|
|
|
u64 defrag_trans_start;
|
2007-08-07 20:15:09 +00:00
|
|
|
struct btrfs_key defrag_progress;
|
2008-05-24 18:04:53 +00:00
|
|
|
struct btrfs_key defrag_max;
|
2007-08-07 20:15:09 +00:00
|
|
|
int defrag_running;
|
|
|
|
int defrag_level;
|
2007-08-29 19:47:34 +00:00
|
|
|
char *name;
|
2008-01-03 14:08:48 +00:00
|
|
|
int in_sysfs;
|
2008-03-24 19:01:56 +00:00
|
|
|
|
|
|
|
/* the dirty list is only used by non-reference counted roots */
|
|
|
|
struct list_head dirty_list;
|
2008-07-24 16:17:14 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct list_head root_list;
|
|
|
|
|
2008-07-30 20:29:20 +00:00
|
|
|
spinlock_t list_lock;
|
2008-07-24 16:17:14 +00:00
|
|
|
struct list_head orphan_list;
|
2008-11-18 01:42:26 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
spinlock_t inode_lock;
|
|
|
|
/* red-black tree that keeps track of in-memory inodes */
|
|
|
|
struct rb_root inode_tree;
|
|
|
|
|
2008-11-18 01:42:26 +00:00
|
|
|
/*
|
|
|
|
* right now this just gets used so that a root has its own devid
|
|
|
|
* for stat. It may be used for more later
|
|
|
|
*/
|
|
|
|
struct super_block anon_super;
|
2007-03-15 16:56:47 +00:00
|
|
|
};
|
|
|
|
|
2007-03-15 23:03:33 +00:00
|
|
|
/*
|
|
|
|
* inode items have the data typically returned from stat and store other
|
|
|
|
* info about object characteristics. There is one for every file and dir in
|
|
|
|
* the FS
|
|
|
|
*/
|
2007-04-26 20:46:15 +00:00
|
|
|
#define BTRFS_INODE_ITEM_KEY 1
|
2008-11-18 01:37:39 +00:00
|
|
|
#define BTRFS_INODE_REF_KEY 12
|
|
|
|
#define BTRFS_XATTR_ITEM_KEY 24
|
|
|
|
#define BTRFS_ORPHAN_ITEM_KEY 48
|
2007-04-26 20:46:15 +00:00
|
|
|
/* reserve 2-15 close to the inode for later flexibility */
|
2007-03-15 23:03:33 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* dir items are the name -> inode pointers in a directory. There is one
|
|
|
|
* for every name in a directory.
|
|
|
|
*/
|
2008-11-18 01:37:39 +00:00
|
|
|
#define BTRFS_DIR_LOG_ITEM_KEY 60
|
|
|
|
#define BTRFS_DIR_LOG_INDEX_KEY 72
|
|
|
|
#define BTRFS_DIR_ITEM_KEY 84
|
|
|
|
#define BTRFS_DIR_INDEX_KEY 96
|
2007-03-15 23:03:33 +00:00
|
|
|
/*
|
2007-04-26 20:46:15 +00:00
|
|
|
* extent data is for file data
|
2007-03-15 23:03:33 +00:00
|
|
|
*/
|
2008-11-18 01:37:39 +00:00
|
|
|
#define BTRFS_EXTENT_DATA_KEY 108
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
|
2007-03-29 19:15:27 +00:00
|
|
|
/*
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
* extent csums are stored in a separate tree and hold csums for
|
|
|
|
* an entire extent on disk.
|
2007-03-29 19:15:27 +00:00
|
|
|
*/
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
#define BTRFS_EXTENT_CSUM_KEY 128
|
2007-03-29 19:15:27 +00:00
|
|
|
|
2007-03-15 23:03:33 +00:00
|
|
|
/*
|
2009-04-02 20:46:06 +00:00
|
|
|
* root items point to tree roots. They are typically in the root
|
2007-03-15 23:03:33 +00:00
|
|
|
* tree used by the super block to find all the other trees
|
|
|
|
*/
|
2008-11-18 01:37:39 +00:00
|
|
|
#define BTRFS_ROOT_ITEM_KEY 132
|
|
|
|
|
|
|
|
/*
|
|
|
|
* root backrefs tie subvols and snapshots to the directory entries that
|
|
|
|
* reference them
|
|
|
|
*/
|
|
|
|
#define BTRFS_ROOT_BACKREF_KEY 144
|
|
|
|
|
|
|
|
/*
|
|
|
|
* root refs make a fast index for listing all of the snapshots and
|
|
|
|
* subvolumes referenced by a given root. They point directly to the
|
|
|
|
* directory item in the root that references the subvol
|
|
|
|
*/
|
|
|
|
#define BTRFS_ROOT_REF_KEY 156
|
|
|
|
|
2007-03-15 23:03:33 +00:00
|
|
|
/*
|
|
|
|
* extent items are in the extent map tree. These record which blocks
|
|
|
|
* are used, and how many references there are to each block
|
|
|
|
*/
|
2008-11-18 01:37:39 +00:00
|
|
|
#define BTRFS_EXTENT_ITEM_KEY 168
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
|
|
|
|
#define BTRFS_TREE_BLOCK_REF_KEY 176
|
|
|
|
|
|
|
|
#define BTRFS_EXTENT_DATA_REF_KEY 178
|
|
|
|
|
|
|
|
#define BTRFS_EXTENT_REF_V0_KEY 180
|
|
|
|
|
|
|
|
#define BTRFS_SHARED_BLOCK_REF_KEY 182
|
|
|
|
|
|
|
|
#define BTRFS_SHARED_DATA_REF_KEY 184
|
2007-04-26 20:46:15 +00:00
|
|
|
|
|
|
|
/*
|
|
|
|
* block groups give us hints into the extent allocation trees. Which
|
|
|
|
* blocks are free etc etc
|
|
|
|
*/
|
2008-11-18 01:37:39 +00:00
|
|
|
#define BTRFS_BLOCK_GROUP_ITEM_KEY 192
|
2007-03-20 18:38:32 +00:00
|
|
|
|
2008-11-18 01:37:39 +00:00
|
|
|
#define BTRFS_DEV_EXTENT_KEY 204
|
|
|
|
#define BTRFS_DEV_ITEM_KEY 216
|
|
|
|
#define BTRFS_CHUNK_ITEM_KEY 228
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2007-03-15 23:03:33 +00:00
|
|
|
/*
|
|
|
|
* string items are for debugging. They just store a short string of
|
|
|
|
* data in the FS
|
|
|
|
*/
|
2007-04-26 20:46:15 +00:00
|
|
|
#define BTRFS_STRING_ITEM_KEY 253
|
|
|
|
|
2008-01-09 14:23:21 +00:00
|
|
|
#define BTRFS_MOUNT_NODATASUM (1 << 0)
|
|
|
|
#define BTRFS_MOUNT_NODATACOW (1 << 1)
|
|
|
|
#define BTRFS_MOUNT_NOBARRIER (1 << 2)
|
2008-01-18 15:54:22 +00:00
|
|
|
#define BTRFS_MOUNT_SSD (1 << 3)
|
2008-05-13 17:46:40 +00:00
|
|
|
#define BTRFS_MOUNT_DEGRADED (1 << 4)
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
#define BTRFS_MOUNT_COMPRESS (1 << 5)
|
2009-04-02 20:49:40 +00:00
|
|
|
#define BTRFS_MOUNT_NOTREELOG (1 << 6)
|
2009-04-02 20:59:01 +00:00
|
|
|
#define BTRFS_MOUNT_FLUSHONCOMMIT (1 << 7)
|
2009-06-10 00:28:34 +00:00
|
|
|
#define BTRFS_MOUNT_SSD_SPREAD (1 << 8)
|
2009-06-10 13:51:32 +00:00
|
|
|
#define BTRFS_MOUNT_NOSSD (1 << 9)
|
2009-10-14 13:24:59 +00:00
|
|
|
#define BTRFS_MOUNT_DISCARD (1 << 10)
|
2007-12-14 20:30:32 +00:00
|
|
|
|
|
|
|
#define btrfs_clear_opt(o, opt) ((o) &= ~BTRFS_MOUNT_##opt)
|
|
|
|
#define btrfs_set_opt(o, opt) ((o) |= BTRFS_MOUNT_##opt)
|
|
|
|
#define btrfs_test_opt(root, opt) ((root)->fs_info->mount_opt & \
|
|
|
|
BTRFS_MOUNT_##opt)
|
2008-01-08 20:54:37 +00:00
|
|
|
/*
|
|
|
|
* Inode flags
|
|
|
|
*/
|
2008-01-14 18:26:08 +00:00
|
|
|
#define BTRFS_INODE_NODATASUM (1 << 0)
|
|
|
|
#define BTRFS_INODE_NODATACOW (1 << 1)
|
|
|
|
#define BTRFS_INODE_READONLY (1 << 2)
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
#define BTRFS_INODE_NOCOMPRESS (1 << 3)
|
2008-10-30 18:25:28 +00:00
|
|
|
#define BTRFS_INODE_PREALLOC (1 << 4)
|
2009-04-17 08:37:41 +00:00
|
|
|
#define BTRFS_INODE_SYNC (1 << 5)
|
|
|
|
#define BTRFS_INODE_IMMUTABLE (1 << 6)
|
|
|
|
#define BTRFS_INODE_APPEND (1 << 7)
|
|
|
|
#define BTRFS_INODE_NODUMP (1 << 8)
|
|
|
|
#define BTRFS_INODE_NOATIME (1 << 9)
|
|
|
|
#define BTRFS_INODE_DIRSYNC (1 << 10)
|
|
|
|
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* some macros to generate set/get funcs for the struct fields. This
|
|
|
|
* assumes there is a lefoo_to_cpu for every type, so lets make a simple
|
|
|
|
* one for u8:
|
|
|
|
*/
|
|
|
|
#define le8_to_cpu(v) (v)
|
|
|
|
#define cpu_to_le8(v) (v)
|
|
|
|
#define __le8 u8
|
|
|
|
|
|
|
|
#define read_eb_member(eb, ptr, type, member, result) ( \
|
|
|
|
read_extent_buffer(eb, (char *)(result), \
|
|
|
|
((unsigned long)(ptr)) + \
|
|
|
|
offsetof(type, member), \
|
|
|
|
sizeof(((type *)0)->member)))
|
|
|
|
|
|
|
|
#define write_eb_member(eb, ptr, type, member, result) ( \
|
|
|
|
write_extent_buffer(eb, (char *)(result), \
|
|
|
|
((unsigned long)(ptr)) + \
|
|
|
|
offsetof(type, member), \
|
|
|
|
sizeof(((type *)0)->member)))
|
|
|
|
|
2007-10-15 20:18:56 +00:00
|
|
|
#ifndef BTRFS_SETGET_FUNCS
|
2007-10-15 20:14:19 +00:00
|
|
|
#define BTRFS_SETGET_FUNCS(name, type, member, bits) \
|
2007-10-15 20:18:56 +00:00
|
|
|
u##bits btrfs_##name(struct extent_buffer *eb, type *s); \
|
|
|
|
void btrfs_set_##name(struct extent_buffer *eb, type *s, u##bits val);
|
|
|
|
#endif
|
2007-10-15 20:14:19 +00:00
|
|
|
|
|
|
|
#define BTRFS_SETGET_HEADER_FUNCS(name, type, member, bits) \
|
|
|
|
static inline u##bits btrfs_##name(struct extent_buffer *eb) \
|
|
|
|
{ \
|
2008-02-15 15:40:52 +00:00
|
|
|
type *p = kmap_atomic(eb->first_page, KM_USER0); \
|
|
|
|
u##bits res = le##bits##_to_cpu(p->member); \
|
|
|
|
kunmap_atomic(p, KM_USER0); \
|
2007-10-15 20:18:55 +00:00
|
|
|
return res; \
|
2007-10-15 20:14:19 +00:00
|
|
|
} \
|
|
|
|
static inline void btrfs_set_##name(struct extent_buffer *eb, \
|
|
|
|
u##bits val) \
|
|
|
|
{ \
|
2008-02-15 15:40:52 +00:00
|
|
|
type *p = kmap_atomic(eb->first_page, KM_USER0); \
|
|
|
|
p->member = cpu_to_le##bits(val); \
|
|
|
|
kunmap_atomic(p, KM_USER0); \
|
2007-10-15 20:14:19 +00:00
|
|
|
}
|
2007-04-26 20:46:15 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
#define BTRFS_SETGET_STACK_FUNCS(name, type, member, bits) \
|
|
|
|
static inline u##bits btrfs_##name(type *s) \
|
|
|
|
{ \
|
|
|
|
return le##bits##_to_cpu(s->member); \
|
|
|
|
} \
|
|
|
|
static inline void btrfs_set_##name(type *s, u##bits val) \
|
|
|
|
{ \
|
|
|
|
s->member = cpu_to_le##bits(val); \
|
2007-03-15 23:03:33 +00:00
|
|
|
}
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_FUNCS(device_type, struct btrfs_dev_item, type, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(device_total_bytes, struct btrfs_dev_item, total_bytes, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(device_bytes_used, struct btrfs_dev_item, bytes_used, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(device_io_align, struct btrfs_dev_item, io_align, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(device_io_width, struct btrfs_dev_item, io_width, 32);
|
2008-12-08 21:40:21 +00:00
|
|
|
BTRFS_SETGET_FUNCS(device_start_offset, struct btrfs_dev_item,
|
|
|
|
start_offset, 64);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_FUNCS(device_sector_size, struct btrfs_dev_item, sector_size, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(device_id, struct btrfs_dev_item, devid, 64);
|
2008-04-15 19:41:47 +00:00
|
|
|
BTRFS_SETGET_FUNCS(device_group, struct btrfs_dev_item, dev_group, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(device_seek_speed, struct btrfs_dev_item, seek_speed, 8);
|
|
|
|
BTRFS_SETGET_FUNCS(device_bandwidth, struct btrfs_dev_item, bandwidth, 8);
|
2008-11-18 02:11:30 +00:00
|
|
|
BTRFS_SETGET_FUNCS(device_generation, struct btrfs_dev_item, generation, 64);
|
2008-03-24 19:01:56 +00:00
|
|
|
|
2008-03-24 19:02:07 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_type, struct btrfs_dev_item, type, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_total_bytes, struct btrfs_dev_item,
|
|
|
|
total_bytes, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_bytes_used, struct btrfs_dev_item,
|
|
|
|
bytes_used, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_io_align, struct btrfs_dev_item,
|
|
|
|
io_align, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_io_width, struct btrfs_dev_item,
|
|
|
|
io_width, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_sector_size, struct btrfs_dev_item,
|
|
|
|
sector_size, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_id, struct btrfs_dev_item, devid, 64);
|
2008-04-15 19:41:47 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_group, struct btrfs_dev_item,
|
|
|
|
dev_group, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_seek_speed, struct btrfs_dev_item,
|
|
|
|
seek_speed, 8);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_bandwidth, struct btrfs_dev_item,
|
|
|
|
bandwidth, 8);
|
2008-11-18 02:11:30 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_device_generation, struct btrfs_dev_item,
|
|
|
|
generation, 64);
|
2008-03-24 19:02:07 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
static inline char *btrfs_device_uuid(struct btrfs_dev_item *d)
|
|
|
|
{
|
|
|
|
return (char *)d + offsetof(struct btrfs_dev_item, uuid);
|
|
|
|
}
|
|
|
|
|
2008-11-18 02:11:30 +00:00
|
|
|
static inline char *btrfs_device_fsid(struct btrfs_dev_item *d)
|
|
|
|
{
|
|
|
|
return (char *)d + offsetof(struct btrfs_dev_item, fsid);
|
|
|
|
}
|
|
|
|
|
2008-04-15 19:41:47 +00:00
|
|
|
BTRFS_SETGET_FUNCS(chunk_length, struct btrfs_chunk, length, 64);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_FUNCS(chunk_owner, struct btrfs_chunk, owner, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(chunk_stripe_len, struct btrfs_chunk, stripe_len, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(chunk_io_align, struct btrfs_chunk, io_align, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(chunk_io_width, struct btrfs_chunk, io_width, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(chunk_sector_size, struct btrfs_chunk, sector_size, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(chunk_type, struct btrfs_chunk, type, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(chunk_num_stripes, struct btrfs_chunk, num_stripes, 16);
|
2008-04-16 14:49:51 +00:00
|
|
|
BTRFS_SETGET_FUNCS(chunk_sub_stripes, struct btrfs_chunk, sub_stripes, 16);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_FUNCS(stripe_devid, struct btrfs_stripe, devid, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(stripe_offset, struct btrfs_stripe, offset, 64);
|
|
|
|
|
2008-04-15 19:41:47 +00:00
|
|
|
static inline char *btrfs_stripe_dev_uuid(struct btrfs_stripe *s)
|
|
|
|
{
|
|
|
|
return (char *)s + offsetof(struct btrfs_stripe, dev_uuid);
|
|
|
|
}
|
|
|
|
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_length, struct btrfs_chunk, length, 64);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_owner, struct btrfs_chunk, owner, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_stripe_len, struct btrfs_chunk,
|
|
|
|
stripe_len, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_io_align, struct btrfs_chunk,
|
|
|
|
io_align, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_io_width, struct btrfs_chunk,
|
|
|
|
io_width, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_sector_size, struct btrfs_chunk,
|
|
|
|
sector_size, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_type, struct btrfs_chunk, type, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_num_stripes, struct btrfs_chunk,
|
|
|
|
num_stripes, 16);
|
2008-04-16 14:49:51 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_chunk_sub_stripes, struct btrfs_chunk,
|
|
|
|
sub_stripes, 16);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_stripe_devid, struct btrfs_stripe, devid, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(stack_stripe_offset, struct btrfs_stripe, offset, 64);
|
|
|
|
|
|
|
|
static inline struct btrfs_stripe *btrfs_stripe_nr(struct btrfs_chunk *c,
|
|
|
|
int nr)
|
|
|
|
{
|
|
|
|
unsigned long offset = (unsigned long)c;
|
|
|
|
offset += offsetof(struct btrfs_chunk, stripe);
|
|
|
|
offset += nr * sizeof(struct btrfs_stripe);
|
|
|
|
return (struct btrfs_stripe *)offset;
|
|
|
|
}
|
|
|
|
|
2008-04-18 14:29:38 +00:00
|
|
|
static inline char *btrfs_stripe_dev_uuid_nr(struct btrfs_chunk *c, int nr)
|
|
|
|
{
|
|
|
|
return btrfs_stripe_dev_uuid(btrfs_stripe_nr(c, nr));
|
|
|
|
}
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
static inline u64 btrfs_stripe_offset_nr(struct extent_buffer *eb,
|
|
|
|
struct btrfs_chunk *c, int nr)
|
|
|
|
{
|
|
|
|
return btrfs_stripe_offset(eb, btrfs_stripe_nr(c, nr));
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_set_stripe_offset_nr(struct extent_buffer *eb,
|
|
|
|
struct btrfs_chunk *c, int nr,
|
|
|
|
u64 val)
|
|
|
|
{
|
|
|
|
btrfs_set_stripe_offset(eb, btrfs_stripe_nr(c, nr), val);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline u64 btrfs_stripe_devid_nr(struct extent_buffer *eb,
|
|
|
|
struct btrfs_chunk *c, int nr)
|
|
|
|
{
|
|
|
|
return btrfs_stripe_devid(eb, btrfs_stripe_nr(c, nr));
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_set_stripe_devid_nr(struct extent_buffer *eb,
|
|
|
|
struct btrfs_chunk *c, int nr,
|
|
|
|
u64 val)
|
|
|
|
{
|
|
|
|
btrfs_set_stripe_devid(eb, btrfs_stripe_nr(c, nr), val);
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_block_group_item */
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(block_group_used, struct btrfs_block_group_item,
|
|
|
|
used, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(disk_block_group_used, struct btrfs_block_group_item,
|
|
|
|
used, 64);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(block_group_chunk_objectid,
|
|
|
|
struct btrfs_block_group_item, chunk_objectid, 64);
|
2008-04-15 19:41:47 +00:00
|
|
|
|
|
|
|
BTRFS_SETGET_FUNCS(disk_block_group_chunk_objectid,
|
2008-03-24 19:01:56 +00:00
|
|
|
struct btrfs_block_group_item, chunk_objectid, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(disk_block_group_flags,
|
|
|
|
struct btrfs_block_group_item, flags, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(block_group_flags,
|
|
|
|
struct btrfs_block_group_item, flags, 64);
|
2007-03-15 23:03:33 +00:00
|
|
|
|
2007-12-12 19:38:19 +00:00
|
|
|
/* struct btrfs_inode_ref */
|
|
|
|
BTRFS_SETGET_FUNCS(inode_ref_name_len, struct btrfs_inode_ref, name_len, 16);
|
2008-07-24 16:12:38 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_ref_index, struct btrfs_inode_ref, index, 64);
|
2007-12-12 19:38:19 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_inode_item */
|
|
|
|
BTRFS_SETGET_FUNCS(inode_generation, struct btrfs_inode_item, generation, 64);
|
2008-12-08 21:40:21 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_sequence, struct btrfs_inode_item, sequence, 64);
|
2008-09-05 20:13:11 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_transid, struct btrfs_inode_item, transid, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_size, struct btrfs_inode_item, size, 64);
|
2008-10-09 15:46:29 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_nbytes, struct btrfs_inode_item, nbytes, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_block_group, struct btrfs_inode_item, block_group, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(inode_nlink, struct btrfs_inode_item, nlink, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(inode_uid, struct btrfs_inode_item, uid, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(inode_gid, struct btrfs_inode_item, gid, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(inode_mode, struct btrfs_inode_item, mode, 32);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_rdev, struct btrfs_inode_item, rdev, 64);
|
2008-12-02 11:36:08 +00:00
|
|
|
BTRFS_SETGET_FUNCS(inode_flags, struct btrfs_inode_item, flags, 64);
|
2007-03-15 23:03:33 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
static inline struct btrfs_timespec *
|
2007-10-15 20:14:19 +00:00
|
|
|
btrfs_inode_atime(struct btrfs_inode_item *inode_item)
|
2007-03-15 23:03:33 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr = (unsigned long)inode_item;
|
|
|
|
ptr += offsetof(struct btrfs_inode_item, atime);
|
2008-03-24 19:01:56 +00:00
|
|
|
return (struct btrfs_timespec *)ptr;
|
2007-03-15 23:03:33 +00:00
|
|
|
}
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
static inline struct btrfs_timespec *
|
2007-10-15 20:14:19 +00:00
|
|
|
btrfs_inode_mtime(struct btrfs_inode_item *inode_item)
|
2007-03-15 23:03:33 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr = (unsigned long)inode_item;
|
|
|
|
ptr += offsetof(struct btrfs_inode_item, mtime);
|
2008-03-24 19:01:56 +00:00
|
|
|
return (struct btrfs_timespec *)ptr;
|
2007-03-15 23:03:33 +00:00
|
|
|
}
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
static inline struct btrfs_timespec *
|
2007-10-15 20:14:19 +00:00
|
|
|
btrfs_inode_ctime(struct btrfs_inode_item *inode_item)
|
2007-03-15 23:03:33 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr = (unsigned long)inode_item;
|
|
|
|
ptr += offsetof(struct btrfs_inode_item, ctime);
|
2008-03-24 19:01:56 +00:00
|
|
|
return (struct btrfs_timespec *)ptr;
|
2007-03-15 23:03:33 +00:00
|
|
|
}
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
static inline struct btrfs_timespec *
|
2007-10-15 20:14:19 +00:00
|
|
|
btrfs_inode_otime(struct btrfs_inode_item *inode_item)
|
2007-03-15 23:03:33 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr = (unsigned long)inode_item;
|
|
|
|
ptr += offsetof(struct btrfs_inode_item, otime);
|
2008-03-24 19:01:56 +00:00
|
|
|
return (struct btrfs_timespec *)ptr;
|
2007-03-15 23:03:33 +00:00
|
|
|
}
|
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_FUNCS(timespec_sec, struct btrfs_timespec, sec, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
|
2007-03-22 16:13:20 +00:00
|
|
|
|
2008-03-24 19:01:56 +00:00
|
|
|
/* struct btrfs_dev_extent */
|
2008-04-15 19:41:47 +00:00
|
|
|
BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent,
|
|
|
|
chunk_tree, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(dev_extent_chunk_objectid, struct btrfs_dev_extent,
|
|
|
|
chunk_objectid, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(dev_extent_chunk_offset, struct btrfs_dev_extent,
|
|
|
|
chunk_offset, 64);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_FUNCS(dev_extent_length, struct btrfs_dev_extent, length, 64);
|
|
|
|
|
2008-04-15 19:41:47 +00:00
|
|
|
static inline u8 *btrfs_dev_extent_chunk_tree_uuid(struct btrfs_dev_extent *dev)
|
|
|
|
{
|
|
|
|
unsigned long ptr = offsetof(struct btrfs_dev_extent, chunk_tree_uuid);
|
|
|
|
return (u8 *)((unsigned long)dev + ptr);
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BTRFS_SETGET_FUNCS(extent_refs, struct btrfs_extent_item, refs, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(extent_generation, struct btrfs_extent_item,
|
|
|
|
generation, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(extent_flags, struct btrfs_extent_item, flags, 64);
|
2007-12-11 14:25:06 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BTRFS_SETGET_FUNCS(extent_refs_v0, struct btrfs_extent_item_v0, refs, 32);
|
|
|
|
|
|
|
|
|
|
|
|
BTRFS_SETGET_FUNCS(tree_block_level, struct btrfs_tree_block_info, level, 8);
|
|
|
|
|
|
|
|
static inline void btrfs_tree_block_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_tree_block_info *item,
|
|
|
|
struct btrfs_disk_key *key)
|
|
|
|
{
|
|
|
|
read_eb_member(eb, item, struct btrfs_tree_block_info, key, key);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_set_tree_block_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_tree_block_info *item,
|
|
|
|
struct btrfs_disk_key *key)
|
|
|
|
{
|
|
|
|
write_eb_member(eb, item, struct btrfs_tree_block_info, key, key);
|
|
|
|
}
|
2007-03-22 16:13:20 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
BTRFS_SETGET_FUNCS(extent_data_ref_root, struct btrfs_extent_data_ref,
|
|
|
|
root, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(extent_data_ref_objectid, struct btrfs_extent_data_ref,
|
|
|
|
objectid, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(extent_data_ref_offset, struct btrfs_extent_data_ref,
|
|
|
|
offset, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(extent_data_ref_count, struct btrfs_extent_data_ref,
|
|
|
|
count, 32);
|
|
|
|
|
|
|
|
BTRFS_SETGET_FUNCS(shared_data_ref_count, struct btrfs_shared_data_ref,
|
|
|
|
count, 32);
|
|
|
|
|
|
|
|
BTRFS_SETGET_FUNCS(extent_inline_ref_type, struct btrfs_extent_inline_ref,
|
|
|
|
type, 8);
|
|
|
|
BTRFS_SETGET_FUNCS(extent_inline_ref_offset, struct btrfs_extent_inline_ref,
|
|
|
|
offset, 64);
|
|
|
|
|
|
|
|
static inline u32 btrfs_extent_inline_ref_size(int type)
|
|
|
|
{
|
|
|
|
if (type == BTRFS_TREE_BLOCK_REF_KEY ||
|
|
|
|
type == BTRFS_SHARED_BLOCK_REF_KEY)
|
|
|
|
return sizeof(struct btrfs_extent_inline_ref);
|
|
|
|
if (type == BTRFS_SHARED_DATA_REF_KEY)
|
|
|
|
return sizeof(struct btrfs_shared_data_ref) +
|
|
|
|
sizeof(struct btrfs_extent_inline_ref);
|
|
|
|
if (type == BTRFS_EXTENT_DATA_REF_KEY)
|
|
|
|
return sizeof(struct btrfs_extent_data_ref) +
|
|
|
|
offsetof(struct btrfs_extent_inline_ref, offset);
|
|
|
|
BUG();
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
BTRFS_SETGET_FUNCS(ref_root_v0, struct btrfs_extent_ref_v0, root, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(ref_generation_v0, struct btrfs_extent_ref_v0,
|
|
|
|
generation, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(ref_objectid_v0, struct btrfs_extent_ref_v0, objectid, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(ref_count_v0, struct btrfs_extent_ref_v0, count, 32);
|
2007-03-22 16:13:20 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_node */
|
|
|
|
BTRFS_SETGET_FUNCS(key_blockptr, struct btrfs_key_ptr, blockptr, 64);
|
2007-12-11 14:25:06 +00:00
|
|
|
BTRFS_SETGET_FUNCS(key_generation, struct btrfs_key_ptr, generation, 64);
|
2007-03-22 16:13:20 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u64 btrfs_node_blockptr(struct extent_buffer *eb, int nr)
|
2007-03-13 13:49:06 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr;
|
|
|
|
ptr = offsetof(struct btrfs_node, ptrs) +
|
|
|
|
sizeof(struct btrfs_key_ptr) * nr;
|
|
|
|
return btrfs_key_blockptr(eb, (struct btrfs_key_ptr *)ptr);
|
2007-03-13 13:49:06 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_set_node_blockptr(struct extent_buffer *eb,
|
|
|
|
int nr, u64 val)
|
2007-03-13 13:49:06 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr;
|
|
|
|
ptr = offsetof(struct btrfs_node, ptrs) +
|
|
|
|
sizeof(struct btrfs_key_ptr) * nr;
|
|
|
|
btrfs_set_key_blockptr(eb, (struct btrfs_key_ptr *)ptr, val);
|
2007-03-13 13:49:06 +00:00
|
|
|
}
|
|
|
|
|
2007-12-11 14:25:06 +00:00
|
|
|
static inline u64 btrfs_node_ptr_generation(struct extent_buffer *eb, int nr)
|
|
|
|
{
|
|
|
|
unsigned long ptr;
|
|
|
|
ptr = offsetof(struct btrfs_node, ptrs) +
|
|
|
|
sizeof(struct btrfs_key_ptr) * nr;
|
|
|
|
return btrfs_key_generation(eb, (struct btrfs_key_ptr *)ptr);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_set_node_ptr_generation(struct extent_buffer *eb,
|
|
|
|
int nr, u64 val)
|
|
|
|
{
|
|
|
|
unsigned long ptr;
|
|
|
|
ptr = offsetof(struct btrfs_node, ptrs) +
|
|
|
|
sizeof(struct btrfs_key_ptr) * nr;
|
|
|
|
btrfs_set_key_generation(eb, (struct btrfs_key_ptr *)ptr, val);
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:18:55 +00:00
|
|
|
static inline unsigned long btrfs_node_key_ptr_offset(int nr)
|
2007-04-21 00:23:12 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return offsetof(struct btrfs_node, ptrs) +
|
|
|
|
sizeof(struct btrfs_key_ptr) * nr;
|
2007-04-21 00:23:12 +00:00
|
|
|
}
|
|
|
|
|
2007-11-06 20:09:29 +00:00
|
|
|
void btrfs_node_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_disk_key *disk_key, int nr);
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_set_node_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_disk_key *disk_key, int nr)
|
2007-03-13 13:28:32 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr;
|
|
|
|
ptr = btrfs_node_key_ptr_offset(nr);
|
|
|
|
write_eb_member(eb, (struct btrfs_key_ptr *)ptr,
|
|
|
|
struct btrfs_key_ptr, key, disk_key);
|
2007-03-13 13:28:32 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_item */
|
|
|
|
BTRFS_SETGET_FUNCS(item_offset, struct btrfs_item, offset, 32);
|
|
|
|
BTRFS_SETGET_FUNCS(item_size, struct btrfs_item, size, 32);
|
2007-04-21 00:23:12 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline unsigned long btrfs_item_nr_offset(int nr)
|
2007-03-13 13:28:32 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return offsetof(struct btrfs_leaf, items) +
|
|
|
|
sizeof(struct btrfs_item) * nr;
|
2007-03-13 13:28:32 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline struct btrfs_item *btrfs_item_nr(struct extent_buffer *eb,
|
|
|
|
int nr)
|
2007-03-13 00:12:07 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return (struct btrfs_item *)btrfs_item_nr_offset(nr);
|
2007-03-13 00:12:07 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u32 btrfs_item_end(struct extent_buffer *eb,
|
|
|
|
struct btrfs_item *item)
|
2007-03-13 00:12:07 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return btrfs_item_offset(eb, item) + btrfs_item_size(eb, item);
|
2007-03-13 00:12:07 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u32 btrfs_item_end_nr(struct extent_buffer *eb, int nr)
|
2007-03-13 00:12:07 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return btrfs_item_end(eb, btrfs_item_nr(eb, nr));
|
2007-03-13 00:12:07 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u32 btrfs_item_offset_nr(struct extent_buffer *eb, int nr)
|
2007-03-13 00:12:07 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return btrfs_item_offset(eb, btrfs_item_nr(eb, nr));
|
2007-03-13 00:12:07 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u32 btrfs_item_size_nr(struct extent_buffer *eb, int nr)
|
2007-03-13 00:12:07 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return btrfs_item_size(eb, btrfs_item_nr(eb, nr));
|
2007-03-13 00:12:07 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_item_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_disk_key *disk_key, int nr)
|
2007-03-15 19:18:43 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_item *item = btrfs_item_nr(eb, nr);
|
|
|
|
read_eb_member(eb, item, struct btrfs_item, key, disk_key);
|
2007-03-15 19:18:43 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_set_item_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_disk_key *disk_key, int nr)
|
2007-03-15 19:18:43 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_item *item = btrfs_item_nr(eb, nr);
|
|
|
|
write_eb_member(eb, item, struct btrfs_item, key, disk_key);
|
2007-03-15 19:18:43 +00:00
|
|
|
}
|
|
|
|
|
2008-09-05 20:13:11 +00:00
|
|
|
BTRFS_SETGET_FUNCS(dir_log_end, struct btrfs_dir_log_item, end, 64);
|
|
|
|
|
2008-11-18 01:37:39 +00:00
|
|
|
/*
|
|
|
|
* struct btrfs_root_ref
|
|
|
|
*/
|
|
|
|
BTRFS_SETGET_FUNCS(root_ref_dirid, struct btrfs_root_ref, dirid, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(root_ref_sequence, struct btrfs_root_ref, sequence, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(root_ref_name_len, struct btrfs_root_ref, name_len, 16);
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_dir_item */
|
2007-11-16 16:45:54 +00:00
|
|
|
BTRFS_SETGET_FUNCS(dir_data_len, struct btrfs_dir_item, data_len, 16);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_FUNCS(dir_type, struct btrfs_dir_item, type, 8);
|
|
|
|
BTRFS_SETGET_FUNCS(dir_name_len, struct btrfs_dir_item, name_len, 16);
|
2008-09-05 20:13:11 +00:00
|
|
|
BTRFS_SETGET_FUNCS(dir_transid, struct btrfs_dir_item, transid, 64);
|
2007-03-15 19:18:43 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_dir_item_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_dir_item *item,
|
|
|
|
struct btrfs_disk_key *key)
|
2007-03-15 19:18:43 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
read_eb_member(eb, item, struct btrfs_dir_item, location, key);
|
2007-03-15 19:18:43 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_set_dir_item_key(struct extent_buffer *eb,
|
|
|
|
struct btrfs_dir_item *item,
|
|
|
|
struct btrfs_disk_key *key)
|
2007-03-16 12:46:49 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
write_eb_member(eb, item, struct btrfs_dir_item, location, key);
|
2007-03-16 12:46:49 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_disk_key */
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(disk_key_objectid, struct btrfs_disk_key,
|
|
|
|
objectid, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(disk_key_offset, struct btrfs_disk_key, offset, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(disk_key_type, struct btrfs_disk_key, type, 8);
|
2007-03-15 19:18:43 +00:00
|
|
|
|
2007-03-12 20:22:34 +00:00
|
|
|
static inline void btrfs_disk_key_to_cpu(struct btrfs_key *cpu,
|
|
|
|
struct btrfs_disk_key *disk)
|
|
|
|
{
|
|
|
|
cpu->offset = le64_to_cpu(disk->offset);
|
2007-10-15 20:14:19 +00:00
|
|
|
cpu->type = disk->type;
|
2007-03-12 20:22:34 +00:00
|
|
|
cpu->objectid = le64_to_cpu(disk->objectid);
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_cpu_key_to_disk(struct btrfs_disk_key *disk,
|
|
|
|
struct btrfs_key *cpu)
|
|
|
|
{
|
|
|
|
disk->offset = cpu_to_le64(cpu->offset);
|
2007-10-15 20:14:19 +00:00
|
|
|
disk->type = cpu->type;
|
2007-03-12 20:22:34 +00:00
|
|
|
disk->objectid = cpu_to_le64(cpu->objectid);
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_node_key_to_cpu(struct extent_buffer *eb,
|
|
|
|
struct btrfs_key *key, int nr)
|
2007-03-23 19:56:19 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_node_key(eb, &disk_key, nr);
|
|
|
|
btrfs_disk_key_to_cpu(key, &disk_key);
|
2007-03-23 19:56:19 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_item_key_to_cpu(struct extent_buffer *eb,
|
|
|
|
struct btrfs_key *key, int nr)
|
2007-03-23 19:56:19 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_item_key(eb, &disk_key, nr);
|
|
|
|
btrfs_disk_key_to_cpu(key, &disk_key);
|
2007-03-23 19:56:19 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_dir_item_key_to_cpu(struct extent_buffer *eb,
|
|
|
|
struct btrfs_dir_item *item,
|
|
|
|
struct btrfs_key *key)
|
2007-04-21 00:23:12 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_disk_key disk_key;
|
|
|
|
btrfs_dir_item_key(eb, item, &disk_key);
|
|
|
|
btrfs_disk_key_to_cpu(key, &disk_key);
|
2007-04-21 00:23:12 +00:00
|
|
|
}
|
|
|
|
|
2007-08-29 19:47:34 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u8 btrfs_key_type(struct btrfs_key *key)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return key->type;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline void btrfs_set_key_type(struct btrfs_key *key, u8 val)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
key->type = val;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_header */
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_HEADER_FUNCS(header_bytenr, struct btrfs_header, bytenr, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_HEADER_FUNCS(header_generation, struct btrfs_header,
|
|
|
|
generation, 64);
|
|
|
|
BTRFS_SETGET_HEADER_FUNCS(header_owner, struct btrfs_header, owner, 64);
|
|
|
|
BTRFS_SETGET_HEADER_FUNCS(header_nritems, struct btrfs_header, nritems, 32);
|
2008-04-01 15:21:32 +00:00
|
|
|
BTRFS_SETGET_HEADER_FUNCS(header_flags, struct btrfs_header, flags, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_HEADER_FUNCS(header_level, struct btrfs_header, level, 8);
|
2007-04-09 14:42:37 +00:00
|
|
|
|
2008-04-01 15:21:32 +00:00
|
|
|
static inline int btrfs_header_flag(struct extent_buffer *eb, u64 flag)
|
|
|
|
{
|
|
|
|
return (btrfs_header_flags(eb) & flag) == flag;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int btrfs_set_header_flag(struct extent_buffer *eb, u64 flag)
|
|
|
|
{
|
|
|
|
u64 flags = btrfs_header_flags(eb);
|
|
|
|
btrfs_set_header_flags(eb, flags | flag);
|
|
|
|
return (flags & flag) == flag;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline int btrfs_clear_header_flag(struct extent_buffer *eb, u64 flag)
|
|
|
|
{
|
|
|
|
u64 flags = btrfs_header_flags(eb);
|
|
|
|
btrfs_set_header_flags(eb, flags & ~flag);
|
|
|
|
return (flags & flag) == flag;
|
|
|
|
}
|
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
static inline int btrfs_header_backref_rev(struct extent_buffer *eb)
|
|
|
|
{
|
|
|
|
u64 flags = btrfs_header_flags(eb);
|
|
|
|
return flags >> BTRFS_BACKREF_REV_SHIFT;
|
|
|
|
}
|
|
|
|
|
|
|
|
static inline void btrfs_set_header_backref_rev(struct extent_buffer *eb,
|
|
|
|
int rev)
|
|
|
|
{
|
|
|
|
u64 flags = btrfs_header_flags(eb);
|
|
|
|
flags &= ~BTRFS_BACKREF_REV_MASK;
|
|
|
|
flags |= (u64)rev << BTRFS_BACKREF_REV_SHIFT;
|
|
|
|
btrfs_set_header_flags(eb, flags);
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u8 *btrfs_header_fsid(struct extent_buffer *eb)
|
2007-04-09 14:42:37 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr = offsetof(struct btrfs_header, fsid);
|
|
|
|
return (u8 *)ptr;
|
2007-04-09 14:42:37 +00:00
|
|
|
}
|
|
|
|
|
2008-04-15 19:41:47 +00:00
|
|
|
static inline u8 *btrfs_header_chunk_tree_uuid(struct extent_buffer *eb)
|
|
|
|
{
|
|
|
|
unsigned long ptr = offsetof(struct btrfs_header, chunk_tree_uuid);
|
|
|
|
return (u8 *)ptr;
|
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u8 *btrfs_super_fsid(struct extent_buffer *eb)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr = offsetof(struct btrfs_super_block, fsid);
|
|
|
|
return (u8 *)ptr;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline u8 *btrfs_header_csum(struct extent_buffer *eb)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long ptr = offsetof(struct btrfs_header, csum);
|
|
|
|
return (u8 *)ptr;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline struct btrfs_node *btrfs_buffer_node(struct extent_buffer *eb)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return NULL;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline struct btrfs_leaf *btrfs_buffer_leaf(struct extent_buffer *eb)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return NULL;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline struct btrfs_header *btrfs_buffer_header(struct extent_buffer *eb)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return NULL;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline int btrfs_is_leaf(struct extent_buffer *eb)
|
2007-03-13 20:47:54 +00:00
|
|
|
{
|
2009-01-06 02:25:51 +00:00
|
|
|
return btrfs_header_level(eb) == 0;
|
2007-03-13 20:47:54 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_root_item */
|
2008-10-29 18:49:05 +00:00
|
|
|
BTRFS_SETGET_FUNCS(disk_root_generation, struct btrfs_root_item,
|
|
|
|
generation, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_FUNCS(disk_root_refs, struct btrfs_root_item, refs, 32);
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_FUNCS(disk_root_bytenr, struct btrfs_root_item, bytenr, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(disk_root_level, struct btrfs_root_item, level, 8);
|
2007-03-13 20:47:54 +00:00
|
|
|
|
2008-10-29 18:49:05 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_generation, struct btrfs_root_item,
|
|
|
|
generation, 64);
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_bytenr, struct btrfs_root_item, bytenr, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_level, struct btrfs_root_item, level, 8);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_dirid, struct btrfs_root_item, root_dirid, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_refs, struct btrfs_root_item, refs, 32);
|
2008-12-02 11:36:08 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_flags, struct btrfs_root_item, flags, 64);
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_used, struct btrfs_root_item, bytes_used, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_limit, struct btrfs_root_item, byte_limit, 64);
|
2008-10-30 18:20:02 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(root_last_snapshot, struct btrfs_root_item,
|
|
|
|
last_snapshot, 64);
|
2007-03-14 18:14:43 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_super_block */
|
2008-12-02 12:17:45 +00:00
|
|
|
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_bytenr, struct btrfs_super_block, bytenr, 64);
|
2008-05-07 15:43:44 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_flags, struct btrfs_super_block, flags, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_generation, struct btrfs_super_block,
|
|
|
|
generation, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_root, struct btrfs_super_block, root, 64);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_sys_array_size,
|
|
|
|
struct btrfs_super_block, sys_chunk_array_size, 32);
|
2008-10-29 18:49:05 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_chunk_root_generation,
|
|
|
|
struct btrfs_super_block, chunk_root_generation, 64);
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_root_level, struct btrfs_super_block,
|
|
|
|
root_level, 8);
|
2008-03-24 19:01:56 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_chunk_root, struct btrfs_super_block,
|
|
|
|
chunk_root, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_chunk_root_level, struct btrfs_super_block,
|
2008-09-05 20:13:11 +00:00
|
|
|
chunk_root_level, 8);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_log_root, struct btrfs_super_block,
|
|
|
|
log_root, 64);
|
2008-12-08 21:40:21 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_log_root_transid, struct btrfs_super_block,
|
|
|
|
log_root_transid, 64);
|
2008-09-05 20:13:11 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_log_root_level, struct btrfs_super_block,
|
|
|
|
log_root_level, 8);
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_total_bytes, struct btrfs_super_block,
|
|
|
|
total_bytes, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_bytes_used, struct btrfs_super_block,
|
|
|
|
bytes_used, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_sectorsize, struct btrfs_super_block,
|
|
|
|
sectorsize, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_nodesize, struct btrfs_super_block,
|
|
|
|
nodesize, 32);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_leafsize, struct btrfs_super_block,
|
|
|
|
leafsize, 32);
|
2007-11-30 16:30:34 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_stripesize, struct btrfs_super_block,
|
|
|
|
stripesize, 32);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_root_dir, struct btrfs_super_block,
|
|
|
|
root_dir_objectid, 64);
|
2008-03-24 19:02:07 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_num_devices, struct btrfs_super_block,
|
|
|
|
num_devices, 64);
|
2008-12-02 11:36:08 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_compat_flags, struct btrfs_super_block,
|
|
|
|
compat_flags, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_compat_ro_flags, struct btrfs_super_block,
|
|
|
|
compat_flags, 64);
|
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_incompat_flags, struct btrfs_super_block,
|
|
|
|
incompat_flags, 64);
|
2008-12-02 12:17:45 +00:00
|
|
|
BTRFS_SETGET_STACK_FUNCS(super_csum_type, struct btrfs_super_block,
|
|
|
|
csum_type, 16);
|
|
|
|
|
|
|
|
static inline int btrfs_super_csum_size(struct btrfs_super_block *s)
|
|
|
|
{
|
|
|
|
int t = btrfs_super_csum_type(s);
|
|
|
|
BUG_ON(t >= ARRAY_SIZE(btrfs_csum_sizes));
|
|
|
|
return btrfs_csum_sizes[t];
|
|
|
|
}
|
2007-03-21 15:12:56 +00:00
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
static inline unsigned long btrfs_leaf_data(struct extent_buffer *l)
|
2007-03-21 15:12:56 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
return offsetof(struct btrfs_leaf, items);
|
2007-03-21 15:12:56 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:14:19 +00:00
|
|
|
/* struct btrfs_file_extent_item */
|
|
|
|
BTRFS_SETGET_FUNCS(file_extent_type, struct btrfs_file_extent_item, type, 8);
|
2007-03-20 18:38:32 +00:00
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static inline unsigned long
|
|
|
|
btrfs_file_extent_inline_start(struct btrfs_file_extent_item *e)
|
2007-04-19 17:37:44 +00:00
|
|
|
{
|
2007-10-15 20:14:19 +00:00
|
|
|
unsigned long offset = (unsigned long)e;
|
2007-10-15 20:15:53 +00:00
|
|
|
offset += offsetof(struct btrfs_file_extent_item, disk_bytenr);
|
2007-10-15 20:14:19 +00:00
|
|
|
return offset;
|
2007-04-19 17:37:44 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
static inline u32 btrfs_file_extent_calc_inline_size(u32 datasize)
|
|
|
|
{
|
2007-10-15 20:15:53 +00:00
|
|
|
return offsetof(struct btrfs_file_extent_item, disk_bytenr) + datasize;
|
2007-03-20 18:38:32 +00:00
|
|
|
}
|
|
|
|
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_FUNCS(file_extent_disk_bytenr, struct btrfs_file_extent_item,
|
|
|
|
disk_bytenr, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_FUNCS(file_extent_generation, struct btrfs_file_extent_item,
|
|
|
|
generation, 64);
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_FUNCS(file_extent_disk_num_bytes, struct btrfs_file_extent_item,
|
|
|
|
disk_num_bytes, 64);
|
2007-10-15 20:14:19 +00:00
|
|
|
BTRFS_SETGET_FUNCS(file_extent_offset, struct btrfs_file_extent_item,
|
|
|
|
offset, 64);
|
2007-10-15 20:15:53 +00:00
|
|
|
BTRFS_SETGET_FUNCS(file_extent_num_bytes, struct btrfs_file_extent_item,
|
|
|
|
num_bytes, 64);
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
BTRFS_SETGET_FUNCS(file_extent_ram_bytes, struct btrfs_file_extent_item,
|
|
|
|
ram_bytes, 64);
|
|
|
|
BTRFS_SETGET_FUNCS(file_extent_compression, struct btrfs_file_extent_item,
|
|
|
|
compression, 8);
|
|
|
|
BTRFS_SETGET_FUNCS(file_extent_encryption, struct btrfs_file_extent_item,
|
|
|
|
encryption, 8);
|
|
|
|
BTRFS_SETGET_FUNCS(file_extent_other_encoding, struct btrfs_file_extent_item,
|
|
|
|
other_encoding, 16);
|
|
|
|
|
|
|
|
/* this returns the number of file bytes represented by the inline item.
|
|
|
|
* If an item is compressed, this is the uncompressed size
|
|
|
|
*/
|
|
|
|
static inline u32 btrfs_file_extent_inline_len(struct extent_buffer *eb,
|
|
|
|
struct btrfs_file_extent_item *e)
|
|
|
|
{
|
|
|
|
return btrfs_file_extent_ram_bytes(eb, e);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* this returns the number of bytes used by the item on disk, minus the
|
|
|
|
* size of any extent headers. If a file is compressed on disk, this is
|
|
|
|
* the compressed size
|
|
|
|
*/
|
|
|
|
static inline u32 btrfs_file_extent_inline_item_len(struct extent_buffer *eb,
|
|
|
|
struct btrfs_item *e)
|
|
|
|
{
|
|
|
|
unsigned long offset;
|
|
|
|
offset = offsetof(struct btrfs_file_extent_item, disk_bytenr);
|
|
|
|
return btrfs_item_size(eb, e) - offset;
|
|
|
|
}
|
2007-03-20 18:38:32 +00:00
|
|
|
|
2007-03-22 16:13:20 +00:00
|
|
|
static inline struct btrfs_root *btrfs_sb(struct super_block *sb)
|
|
|
|
{
|
|
|
|
return sb->s_fs_info;
|
|
|
|
}
|
|
|
|
|
2007-08-29 19:47:34 +00:00
|
|
|
static inline int btrfs_set_root_name(struct btrfs_root *root,
|
|
|
|
const char *name, int len)
|
|
|
|
{
|
|
|
|
/* if we already have a name just free it */
|
2009-01-06 02:25:51 +00:00
|
|
|
kfree(root->name);
|
2007-08-29 19:47:34 +00:00
|
|
|
|
|
|
|
root->name = kmalloc(len+1, GFP_KERNEL);
|
|
|
|
if (!root->name)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
memcpy(root->name, name, len);
|
2009-01-06 02:25:51 +00:00
|
|
|
root->name[len] = '\0';
|
2007-08-29 19:47:34 +00:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2009-01-06 02:25:51 +00:00
|
|
|
static inline u32 btrfs_level_size(struct btrfs_root *root, int level)
|
|
|
|
{
|
2007-10-15 20:15:53 +00:00
|
|
|
if (level == 0)
|
|
|
|
return root->leafsize;
|
|
|
|
return root->nodesize;
|
|
|
|
}
|
|
|
|
|
2007-03-14 14:31:29 +00:00
|
|
|
/* helper function to cast into the data area of the leaf. */
|
|
|
|
#define btrfs_item_ptr(leaf, slot, type) \
|
2007-03-14 18:14:43 +00:00
|
|
|
((type *)(btrfs_leaf_data(leaf) + \
|
2007-10-15 20:14:19 +00:00
|
|
|
btrfs_item_offset_nr(leaf, slot)))
|
|
|
|
|
|
|
|
#define btrfs_item_ptr_offset(leaf, slot) \
|
|
|
|
((unsigned long)(btrfs_leaf_data(leaf) + \
|
|
|
|
btrfs_item_offset_nr(leaf, slot)))
|
2007-03-14 14:31:29 +00:00
|
|
|
|
2008-09-24 15:48:04 +00:00
|
|
|
static inline struct dentry *fdentry(struct file *file)
|
|
|
|
{
|
2007-12-18 21:15:09 +00:00
|
|
|
return file->f_path.dentry;
|
|
|
|
}
|
|
|
|
|
2007-04-17 17:26:50 +00:00
|
|
|
/* extent-tree.c */
|
2009-04-03 13:47:43 +00:00
|
|
|
void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
|
2009-03-13 14:10:06 +00:00
|
|
|
int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, unsigned long count);
|
2008-09-23 17:14:14 +00:00
|
|
|
int btrfs_lookup_extent(struct btrfs_root *root, u64 start, u64 len);
|
2009-09-11 20:11:19 +00:00
|
|
|
int btrfs_pin_extent(struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num, int reserved);
|
2008-09-05 20:13:11 +00:00
|
|
|
int btrfs_drop_leaf_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, struct extent_buffer *leaf);
|
2008-10-30 18:20:02 +00:00
|
|
|
int btrfs_cross_ref_exist(struct btrfs_trans_handle *trans,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 objectid, u64 offset, u64 bytenr);
|
2008-01-24 21:13:08 +00:00
|
|
|
int btrfs_copy_pinned(struct btrfs_root *root, struct extent_io_tree *copy);
|
2009-01-06 02:25:51 +00:00
|
|
|
struct btrfs_block_group_cache *btrfs_lookup_block_group(
|
|
|
|
struct btrfs_fs_info *info,
|
|
|
|
u64 bytenr);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
void btrfs_put_block_group(struct btrfs_block_group_cache *cache);
|
2008-12-11 21:30:39 +00:00
|
|
|
u64 btrfs_find_block_group(struct btrfs_root *root,
|
|
|
|
u64 search_start, u64 search_hint, int owner);
|
2007-10-15 20:14:19 +00:00
|
|
|
struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct btrfs_root *root, u32 blocksize,
|
|
|
|
u64 parent, u64 root_objectid,
|
|
|
|
struct btrfs_disk_key *key, int level,
|
|
|
|
u64 hint, u64 empty_size);
|
2008-08-01 19:11:20 +00:00
|
|
|
struct extent_buffer *btrfs_init_new_buffer(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
2009-02-12 19:09:45 +00:00
|
|
|
u64 bytenr, u32 blocksize,
|
|
|
|
int level);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 root_objectid, u64 owner,
|
|
|
|
u64 offset, struct btrfs_key *ins);
|
|
|
|
int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 root_objectid, u64 owner, u64 offset,
|
|
|
|
struct btrfs_key *ins);
|
2008-07-17 16:53:50 +00:00
|
|
|
int btrfs_reserve_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 num_bytes, u64 min_alloc_size,
|
|
|
|
u64 empty_size, u64 hint_byte,
|
|
|
|
u64 search_end, struct btrfs_key *ins,
|
|
|
|
u64 data);
|
2007-03-16 20:20:31 +00:00
|
|
|
int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
struct extent_buffer *buf, int full_backref);
|
|
|
|
int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf, int full_backref);
|
|
|
|
int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 flags,
|
|
|
|
int is_data);
|
2008-09-23 17:14:14 +00:00
|
|
|
int btrfs_free_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 parent,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u64 root_objectid, u64 owner, u64 offset);
|
|
|
|
|
2008-08-01 19:11:20 +00:00
|
|
|
int btrfs_free_reserved_extent(struct btrfs_root *root, u64 start, u64 len);
|
2009-09-11 20:11:19 +00:00
|
|
|
int btrfs_prepare_extent_commit(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root);
|
2007-06-28 19:57:36 +00:00
|
|
|
int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
|
2009-09-11 20:11:19 +00:00
|
|
|
struct btrfs_root *root);
|
2007-04-17 17:26:50 +00:00
|
|
|
int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
|
2008-09-23 17:14:14 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 bytenr, u64 num_bytes, u64 parent,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
u64 root_objectid, u64 owner, u64 offset);
|
|
|
|
|
2007-04-26 20:46:15 +00:00
|
|
|
int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root);
|
2008-12-11 21:30:39 +00:00
|
|
|
int btrfs_extent_readonly(struct btrfs_root *root, u64 bytenr);
|
2007-04-26 20:46:15 +00:00
|
|
|
int btrfs_free_block_groups(struct btrfs_fs_info *info);
|
|
|
|
int btrfs_read_block_groups(struct btrfs_root *root);
|
Btrfs: make balance code choose more wisely when relocating
Currently, we can panic the box if the first block group we go to move is of a
type where there is no space left to move those extents. For example, if we
fill the disk up with data, and then we try to balance and we have no room to
move the data nor room to allocate new chunks, we will panic. Change this by
checking to see if we have room to move this chunk around, and if not, return
-ENOSPC and move on to the next chunk. This will make sure we remove block
groups that are moveable, like if we have alot of empty metadata block groups,
and then that way we make room to be able to balance our data chunks as well.
Tested this with an fs that would panic on btrfs-vol -b normally, but no longer
panics with this patch.
V1->V2:
-actually search for a free extent on the device to make sure we can allocate a
chunk if need be.
-fix btrfs_shrink_device to make sure we actually try to relocate all the
chunks, and then if we can't return -ENOSPC so if we are doing a btrfs-vol -r
we don't remove the device with data still on it.
-check to make sure the block group we are going to relocate isn't the last one
in that particular space
-fix a bug in btrfs_shrink_device where we would change the device's size and
not fix it if we fail to do our relocate
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-09-11 20:11:19 +00:00
|
|
|
int btrfs_can_relocate(struct btrfs_root *root, u64 bytenr);
|
2008-03-24 19:01:56 +00:00
|
|
|
int btrfs_make_block_group(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 bytes_used,
|
2008-04-15 19:41:47 +00:00
|
|
|
u64 type, u64 chunk_objectid, u64 chunk_offset,
|
2008-03-24 19:01:56 +00:00
|
|
|
u64 size);
|
Btrfs: update space balancing code
This patch updates the space balancing code to utilize the new
backref format. Before, btrfs-vol -b would break any COW links
on data blocks or metadata. This was slow and caused the amount
of space used to explode if a large number of snapshots were present.
The new code can keeps the sharing of all data extents and
most of the tree blocks.
To maintain the sharing of data extents, the space balance code uses
a seperate inode hold data extent pointers, then updates the references
to point to the new location.
To maintain the sharing of tree blocks, the space balance code uses
reloc trees to relocate tree blocks in reference counted roots.
There is one reloc tree for each subvol, and all reloc trees share
same root key objectid. Reloc trees are snapshots of the latest
committed roots of subvols (root->commit_root).
To relocate a tree block referenced by a subvol, there are two steps.
COW the block through subvol's reloc tree, then update block pointer in
the subvol to point to the new block. Since all reloc trees share
same root key objectid, doing special handing for tree blocks
owned by them is easy. Once a tree block has been COWed in one
reloc tree, we can use the resulting new block directly when the
same block is required to COW again through other reloc trees.
In this way, relocated tree blocks are shared between reloc trees,
so they are also shared between subvols.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-26 14:09:34 +00:00
|
|
|
int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 group_start);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_prepare_block_group_relocation(struct btrfs_root *root,
|
|
|
|
struct btrfs_block_group_cache *group);
|
|
|
|
|
2008-11-18 02:11:30 +00:00
|
|
|
u64 btrfs_reduce_alloc_profile(struct btrfs_root *root, u64 flags);
|
2009-02-20 16:00:09 +00:00
|
|
|
void btrfs_set_inode_space_info(struct btrfs_root *root, struct inode *ionde);
|
2009-03-10 16:39:20 +00:00
|
|
|
void btrfs_clear_space_info_full(struct btrfs_fs_info *info);
|
|
|
|
|
2009-09-11 20:12:44 +00:00
|
|
|
int btrfs_reserve_metadata_space(struct btrfs_root *root, int num_items);
|
|
|
|
int btrfs_unreserve_metadata_space(struct btrfs_root *root, int num_items);
|
|
|
|
int btrfs_unreserve_metadata_for_delalloc(struct btrfs_root *root,
|
|
|
|
struct inode *inode, int num_items);
|
|
|
|
int btrfs_reserve_metadata_for_delalloc(struct btrfs_root *root,
|
|
|
|
struct inode *inode, int num_items);
|
2009-02-20 16:00:09 +00:00
|
|
|
int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode,
|
|
|
|
u64 bytes);
|
|
|
|
void btrfs_free_reserved_data_space(struct btrfs_root *root,
|
|
|
|
struct inode *inode, u64 bytes);
|
|
|
|
void btrfs_delalloc_reserve_space(struct btrfs_root *root, struct inode *inode,
|
|
|
|
u64 bytes);
|
|
|
|
void btrfs_delalloc_free_space(struct btrfs_root *root, struct inode *inode,
|
|
|
|
u64 bytes);
|
2007-03-26 20:00:06 +00:00
|
|
|
/* ctree.c */
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_bin_search(struct extent_buffer *eb, struct btrfs_key *key,
|
|
|
|
int level, int *slot);
|
|
|
|
int btrfs_comp_cpu_keys(struct btrfs_key *k1, struct btrfs_key *k2);
|
2008-03-24 19:01:56 +00:00
|
|
|
int btrfs_previous_item(struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 min_objectid,
|
|
|
|
int type);
|
2008-09-23 17:14:14 +00:00
|
|
|
int btrfs_set_item_key_safe(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, struct btrfs_path *path,
|
|
|
|
struct btrfs_key *new_key);
|
2008-06-25 20:01:30 +00:00
|
|
|
struct extent_buffer *btrfs_root_node(struct btrfs_root *root);
|
|
|
|
struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root);
|
2008-06-25 20:01:31 +00:00
|
|
|
int btrfs_find_next_key(struct btrfs_root *root, struct btrfs_path *path,
|
2008-06-25 20:01:31 +00:00
|
|
|
struct btrfs_key *key, int lowest_level,
|
|
|
|
int cache_only, u64 min_trans);
|
|
|
|
int btrfs_search_forward(struct btrfs_root *root, struct btrfs_key *min_key,
|
2008-09-05 20:13:11 +00:00
|
|
|
struct btrfs_key *max_key,
|
2008-06-25 20:01:31 +00:00
|
|
|
struct btrfs_path *path, int cache_only,
|
|
|
|
u64 min_trans);
|
2007-10-15 20:14:19 +00:00
|
|
|
int btrfs_cow_block(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, struct extent_buffer *buf,
|
|
|
|
struct extent_buffer *parent, int parent_slot,
|
2009-03-13 14:24:59 +00:00
|
|
|
struct extent_buffer **cow_ret);
|
2007-12-18 01:14:01 +00:00
|
|
|
int btrfs_copy_root(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf,
|
|
|
|
struct extent_buffer **cow_ret, u64 new_root_objectid);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_block_can_be_shared(struct btrfs_root *root,
|
|
|
|
struct extent_buffer *buf);
|
2007-04-16 13:22:45 +00:00
|
|
|
int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
|
|
*root, struct btrfs_path *path, u32 data_size);
|
2007-04-17 17:26:50 +00:00
|
|
|
int btrfs_truncate_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
2007-11-01 15:28:41 +00:00
|
|
|
u32 new_size, int from_end);
|
2008-12-10 14:10:46 +00:00
|
|
|
int btrfs_split_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *new_key,
|
|
|
|
unsigned long split_offset);
|
2009-11-12 09:33:58 +00:00
|
|
|
int btrfs_duplicate_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *new_key);
|
2007-03-16 20:20:31 +00:00
|
|
|
int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
|
|
*root, struct btrfs_key *key, struct btrfs_path *p, int
|
|
|
|
ins_len, int cow);
|
2007-08-07 20:15:09 +00:00
|
|
|
int btrfs_realloc_node(struct btrfs_trans_handle *trans,
|
2007-10-15 20:14:19 +00:00
|
|
|
struct btrfs_root *root, struct extent_buffer *parent,
|
2007-10-15 20:22:39 +00:00
|
|
|
int start_slot, int cache_only, u64 *last_ret,
|
|
|
|
struct btrfs_key *progress);
|
2007-03-13 14:46:10 +00:00
|
|
|
void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);
|
2007-04-02 14:50:19 +00:00
|
|
|
struct btrfs_path *btrfs_alloc_path(void);
|
|
|
|
void btrfs_free_path(struct btrfs_path *p);
|
Btrfs: Change btree locking to use explicit blocking points
Most of the btrfs metadata operations can be protected by a spinlock,
but some operations still need to schedule.
So far, btrfs has been using a mutex along with a trylock loop,
most of the time it is able to avoid going for the full mutex, so
the trylock loop is a big performance gain.
This commit is step one for getting rid of the blocking locks entirely.
btrfs_tree_lock takes a spinlock, and the code explicitly switches
to a blocking lock when it starts an operation that can schedule.
We'll be able get rid of the blocking locks in smaller pieces over time.
Tracing allows us to find the most common cause of blocking, so we
can start with the hot spots first.
The basic idea is:
btrfs_tree_lock() returns with the spin lock held
btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in
the extent buffer flags, and then drops the spin lock. The buffer is
still considered locked by all of the btrfs code.
If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops
the spin lock and waits on a wait queue for the blocking bit to go away.
Much of the code that needs to set the blocking bit finishes without actually
blocking a good percentage of the time. So, an adaptive spin is still
used against the blocking bit to avoid very high context switch rates.
btrfs_clear_lock_blocking() clears the blocking bit and returns
with the spinlock held again.
btrfs_tree_unlock() can be called on either blocking or spinning locks,
it does the right thing based on the blocking bit.
ctree.c has a helper function to set/clear all the locked buffers in a
path as blocking.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 14:25:08 +00:00
|
|
|
void btrfs_set_path_blocking(struct btrfs_path *p);
|
|
|
|
void btrfs_unlock_up_safe(struct btrfs_path *p, int level);
|
|
|
|
|
2008-01-29 20:11:36 +00:00
|
|
|
int btrfs_del_items(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, int slot, int nr);
|
|
|
|
static inline int btrfs_del_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path)
|
|
|
|
{
|
|
|
|
return btrfs_del_items(trans, root, path, path->slots[0], 1);
|
|
|
|
}
|
|
|
|
|
2007-03-16 20:20:31 +00:00
|
|
|
int btrfs_insert_item(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
|
|
*root, struct btrfs_key *key, void *data, u32 data_size);
|
2008-11-12 19:19:50 +00:00
|
|
|
int btrfs_insert_some_items(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *cpu_key, u32 *data_size,
|
|
|
|
int nr);
|
2008-01-29 20:15:18 +00:00
|
|
|
int btrfs_insert_empty_items(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *cpu_key, u32 *data_size, int nr);
|
|
|
|
|
|
|
|
static inline int btrfs_insert_empty_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_key *key,
|
|
|
|
u32 data_size)
|
|
|
|
{
|
|
|
|
return btrfs_insert_empty_items(trans, root, path, key, &data_size, 1);
|
|
|
|
}
|
|
|
|
|
2007-03-13 14:46:10 +00:00
|
|
|
int btrfs_next_leaf(struct btrfs_root *root, struct btrfs_path *path);
|
2007-12-11 14:25:06 +00:00
|
|
|
int btrfs_prev_leaf(struct btrfs_root *root, struct btrfs_path *path);
|
2007-10-15 20:14:19 +00:00
|
|
|
int btrfs_leaf_free_space(struct btrfs_root *root, struct extent_buffer *leaf);
|
2009-06-28 01:07:35 +00:00
|
|
|
int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref);
|
2008-10-29 18:49:05 +00:00
|
|
|
int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct extent_buffer *node,
|
|
|
|
struct extent_buffer *parent);
|
2007-03-26 20:00:06 +00:00
|
|
|
/* root-item.c */
|
2008-11-18 02:14:24 +00:00
|
|
|
int btrfs_find_root_ref(struct btrfs_root *tree_root,
|
2009-09-21 19:56:00 +00:00
|
|
|
struct btrfs_path *path,
|
|
|
|
u64 root_id, u64 ref_id);
|
2008-11-18 01:37:39 +00:00
|
|
|
int btrfs_add_root_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *tree_root,
|
2009-09-21 19:56:00 +00:00
|
|
|
u64 root_id, u64 ref_id, u64 dirid, u64 sequence,
|
|
|
|
const char *name, int name_len);
|
|
|
|
int btrfs_del_root_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *tree_root,
|
|
|
|
u64 root_id, u64 ref_id, u64 dirid, u64 *sequence,
|
2008-11-18 01:37:39 +00:00
|
|
|
const char *name, int name_len);
|
2007-03-16 20:20:31 +00:00
|
|
|
int btrfs_del_root(struct btrfs_trans_handle *trans, struct btrfs_root *root,
|
|
|
|
struct btrfs_key *key);
|
|
|
|
int btrfs_insert_root(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
|
|
*root, struct btrfs_key *key, struct btrfs_root_item
|
|
|
|
*item);
|
|
|
|
int btrfs_update_root(struct btrfs_trans_handle *trans, struct btrfs_root
|
|
|
|
*root, struct btrfs_key *key, struct btrfs_root_item
|
|
|
|
*item);
|
|
|
|
int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, struct
|
|
|
|
btrfs_root_item *item, struct btrfs_key *key);
|
2008-05-08 17:26:18 +00:00
|
|
|
int btrfs_search_root(struct btrfs_root *root, u64 search_start,
|
|
|
|
u64 *found_objectid);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_find_dead_roots(struct btrfs_root *root, u64 objectid);
|
2009-09-21 20:00:26 +00:00
|
|
|
int btrfs_find_orphan_roots(struct btrfs_root *tree_root);
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
int btrfs_set_root_node(struct btrfs_root_item *item,
|
|
|
|
struct extent_buffer *node);
|
2007-03-26 20:00:06 +00:00
|
|
|
/* dir-item.c */
|
2009-01-06 02:25:51 +00:00
|
|
|
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, const char *name,
|
|
|
|
int name_len, u64 dir,
|
2008-07-24 16:12:38 +00:00
|
|
|
struct btrfs_key *location, u8 type, u64 index);
|
2007-04-19 19:36:27 +00:00
|
|
|
struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 dir,
|
|
|
|
const char *name, int name_len,
|
|
|
|
int mod);
|
|
|
|
struct btrfs_dir_item *
|
|
|
|
btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 dir,
|
|
|
|
u64 objectid, const char *name, int name_len,
|
|
|
|
int mod);
|
2009-09-21 19:56:00 +00:00
|
|
|
struct btrfs_dir_item *
|
|
|
|
btrfs_search_dir_index_item(struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 dirid,
|
|
|
|
const char *name, int name_len);
|
2007-04-19 19:36:27 +00:00
|
|
|
struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
2007-03-23 19:56:19 +00:00
|
|
|
const char *name, int name_len);
|
2007-04-19 19:36:27 +00:00
|
|
|
int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
|
|
|
struct btrfs_dir_item *di);
|
2007-11-16 16:45:54 +00:00
|
|
|
int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, const char *name,
|
|
|
|
u16 name_len, const void *data, u16 data_len,
|
|
|
|
u64 dir);
|
|
|
|
struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 dir,
|
|
|
|
const char *name, u16 name_len,
|
|
|
|
int mod);
|
2008-07-24 16:17:14 +00:00
|
|
|
|
|
|
|
/* orphan.c */
|
|
|
|
int btrfs_insert_orphan_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 offset);
|
|
|
|
int btrfs_del_orphan_item(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 offset);
|
2009-09-21 19:56:00 +00:00
|
|
|
int btrfs_find_orphan_item(struct btrfs_root *root, u64 offset);
|
2008-07-24 16:17:14 +00:00
|
|
|
|
2007-03-26 20:00:06 +00:00
|
|
|
/* inode-map.c */
|
2007-03-20 18:38:32 +00:00
|
|
|
int btrfs_find_free_objectid(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *fs_root,
|
|
|
|
u64 dirid, u64 *objectid);
|
2007-04-05 17:35:25 +00:00
|
|
|
int btrfs_find_highest_inode(struct btrfs_root *fs_root, u64 *objectid);
|
|
|
|
|
2007-03-26 20:00:06 +00:00
|
|
|
/* inode-item.c */
|
2007-12-12 19:38:19 +00:00
|
|
|
int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
const char *name, int name_len,
|
2008-07-24 16:12:38 +00:00
|
|
|
u64 inode_objectid, u64 ref_objectid, u64 index);
|
2007-12-12 19:38:19 +00:00
|
|
|
int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
const char *name, int name_len,
|
2008-07-24 16:12:38 +00:00
|
|
|
u64 inode_objectid, u64 ref_objectid, u64 *index);
|
2007-10-15 20:14:19 +00:00
|
|
|
int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 objectid);
|
2007-03-20 19:57:25 +00:00
|
|
|
int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
|
2007-04-06 19:37:36 +00:00
|
|
|
*root, struct btrfs_path *path,
|
|
|
|
struct btrfs_key *location, int mod);
|
2007-03-26 20:00:06 +00:00
|
|
|
|
|
|
|
/* file-item.c */
|
2008-12-10 14:10:46 +00:00
|
|
|
int btrfs_del_csums(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, u64 bytenr, u64 len);
|
2008-07-31 19:42:53 +00:00
|
|
|
int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode,
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
struct bio *bio, u32 *dst);
|
2007-04-17 17:26:50 +00:00
|
|
|
int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
struct btrfs_root *root,
|
|
|
|
u64 objectid, u64 pos,
|
|
|
|
u64 disk_offset, u64 disk_num_bytes,
|
|
|
|
u64 num_bytes, u64 offset, u64 ram_bytes,
|
|
|
|
u8 compression, u8 encryption, u16 other_encoding);
|
2007-03-26 20:00:06 +00:00
|
|
|
int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path, u64 objectid,
|
2007-10-15 20:15:53 +00:00
|
|
|
u64 bytenr, int mod);
|
2008-02-20 17:07:25 +00:00
|
|
|
int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans,
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
struct btrfs_root *root,
|
2008-07-17 16:53:50 +00:00
|
|
|
struct btrfs_ordered_sum *sums);
|
2008-07-18 10:17:13 +00:00
|
|
|
int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode,
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
struct bio *bio, u64 file_start, int contig);
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
int btrfs_csum_file_bytes(struct btrfs_root *root, struct inode *inode,
|
|
|
|
u64 start, unsigned long len);
|
2007-04-17 17:26:50 +00:00
|
|
|
struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct btrfs_path *path,
|
Btrfs: move data checksumming into a dedicated tree
Btrfs stores checksums for each data block. Until now, they have
been stored in the subvolume trees, indexed by the inode that is
referencing the data block. This means that when we read the inode,
we've probably read in at least some checksums as well.
But, this has a few problems:
* The checksums are indexed by logical offset in the file. When
compression is on, this means we have to do the expensive checksumming
on the uncompressed data. It would be faster if we could checksum
the compressed data instead.
* If we implement encryption, we'll be checksumming the plain text and
storing that on disk. This is significantly less secure.
* For either compression or encryption, we have to get the plain text
back before we can verify the checksum as correct. This makes the raid
layer balancing and extent moving much more expensive.
* It makes the front end caching code more complex, as we have touch
the subvolume and inodes as we cache extents.
* There is potentitally one copy of the checksum in each subvolume
referencing an extent.
The solution used here is to store the extent checksums in a dedicated
tree. This allows us to index the checksums by phyiscal extent
start and length. It means:
* The checksum is against the data stored on disk, after any compression
or encryption is done.
* The checksum is stored in a central location, and can be verified without
following back references, or reading inodes.
This makes compression significantly faster by reducing the amount of
data that needs to be checksummed. It will also allow much faster
raid management code in general.
The checksums are indexed by a key with a fixed objectid (a magic value
in ctree.h) and offset set to the starting byte of the extent. This
allows us to copy the checksum items into the fsync log tree directly (or
any other tree), without having to invent a second format for them.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-08 21:58:54 +00:00
|
|
|
u64 bytenr, int cow);
|
2007-05-29 19:17:08 +00:00
|
|
|
int btrfs_csum_truncate(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root, struct btrfs_path *path,
|
|
|
|
u64 isize);
|
2008-12-12 15:03:38 +00:00
|
|
|
int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start,
|
|
|
|
u64 end, struct list_head *list);
|
2007-06-12 10:35:45 +00:00
|
|
|
/* inode.c */
|
2008-07-24 13:51:08 +00:00
|
|
|
|
|
|
|
/* RHEL and EL kernels have a patch that renames PG_checked to FsMisc */
|
2008-08-07 15:19:42 +00:00
|
|
|
#if defined(ClearPageFsMisc) && !defined(ClearPageChecked)
|
2008-07-24 13:51:08 +00:00
|
|
|
#define ClearPageChecked ClearPageFsMisc
|
|
|
|
#define SetPageChecked SetPageFsMisc
|
|
|
|
#define PageChecked PageFsMisc
|
|
|
|
#endif
|
|
|
|
|
2008-11-18 02:02:50 +00:00
|
|
|
struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry);
|
|
|
|
int btrfs_set_inode_index(struct inode *dir, u64 *index);
|
2008-09-05 20:13:11 +00:00
|
|
|
int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct inode *dir, struct inode *inode,
|
|
|
|
const char *name, int name_len);
|
|
|
|
int btrfs_add_link(struct btrfs_trans_handle *trans,
|
|
|
|
struct inode *parent_inode, struct inode *inode,
|
|
|
|
const char *name, int name_len, int add_backref, u64 index);
|
2009-09-21 19:56:00 +00:00
|
|
|
int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct inode *dir, u64 objectid,
|
|
|
|
const char *name, int name_len);
|
2008-09-05 20:13:11 +00:00
|
|
|
int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root,
|
|
|
|
struct inode *inode, u64 new_size,
|
|
|
|
u32 min_type);
|
|
|
|
|
2008-08-05 03:17:27 +00:00
|
|
|
int btrfs_start_delalloc_inodes(struct btrfs_root *root);
|
|
|
|
int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end);
|
2008-07-22 15:18:09 +00:00
|
|
|
int btrfs_writepages(struct address_space *mapping,
|
|
|
|
struct writeback_control *wbc);
|
2008-12-11 21:30:39 +00:00
|
|
|
int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
|
2009-09-21 20:00:26 +00:00
|
|
|
struct btrfs_root *new_root,
|
2008-12-11 21:30:39 +00:00
|
|
|
u64 new_dirid, u64 alloc_hint);
|
2008-03-24 19:02:07 +00:00
|
|
|
int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
|
Btrfs: Add zlib compression support
This is a large change for adding compression on reading and writing,
both for inline and regular extents. It does some fairly large
surgery to the writeback paths.
Compression is off by default and enabled by mount -o compress. Even
when the -o compress mount option is not used, it is possible to read
compressed extents off the disk.
If compression for a given set of pages fails to make them smaller, the
file is flagged to avoid future compression attempts later.
* While finding delalloc extents, the pages are locked before being sent down
to the delalloc handler. This allows the delalloc handler to do complex things
such as cleaning the pages, marking them writeback and starting IO on their
behalf.
* Inline extents are inserted at delalloc time now. This allows us to compress
the data before inserting the inline extent, and it allows us to insert
an inline extent that spans multiple pages.
* All of the in-memory extent representations (extent_map.c, ordered-data.c etc)
are changed to record both an in-memory size and an on disk size, as well
as a flag for compression.
From a disk format point of view, the extent pointers in the file are changed
to record the on disk size of a given extent and some encoding flags.
Space in the disk format is allocated for compression encoding, as well
as encryption and a generic 'other' field. Neither the encryption or the
'other' field are currently used.
In order to limit the amount of data read for a single random read in the
file, the size of a compressed extent is limited to 128k. This is a
software only limit, the disk format supports u64 sized compressed extents.
In order to limit the ram consumed while processing extents, the uncompressed
size of a compressed extent is limited to 256k. This is a software only limit
and will be subject to tuning later.
Checksumming is still done on compressed extents, and it is done on the
uncompressed version of the data. This way additional encodings can be
layered on without having to figure out which encoding to checksum.
Compression happens at delalloc time, which is basically singled threaded because
it is usually done by a single pdflush thread. This makes it tricky to
spread the compression load across all the cpus on the box. We'll have to
look at parallel pdflush walks of dirty inodes at a later time.
Decompression is hooked into readpages and it does spread across CPUs nicely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-10-29 18:49:59 +00:00
|
|
|
size_t size, struct bio *bio, unsigned long bio_flags);
|
2008-03-24 19:02:07 +00:00
|
|
|
|
2007-12-21 21:27:24 +00:00
|
|
|
unsigned long btrfs_force_ra(struct address_space *mapping,
|
|
|
|
struct file_ra_state *ra, struct file *file,
|
|
|
|
pgoff_t offset, pgoff_t last_index);
|
2009-03-31 22:23:21 +00:00
|
|
|
int btrfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
|
2007-06-15 17:50:00 +00:00
|
|
|
int btrfs_readpage(struct file *file, struct page *page);
|
2007-06-12 10:35:45 +00:00
|
|
|
void btrfs_delete_inode(struct inode *inode);
|
2008-01-16 16:44:43 +00:00
|
|
|
void btrfs_put_inode(struct inode *inode);
|
2007-06-12 10:35:45 +00:00
|
|
|
int btrfs_write_inode(struct inode *inode, int wait);
|
|
|
|
void btrfs_dirty_inode(struct inode *inode);
|
|
|
|
struct inode *btrfs_alloc_inode(struct super_block *sb);
|
|
|
|
void btrfs_destroy_inode(struct inode *inode);
|
2009-09-21 20:00:26 +00:00
|
|
|
void btrfs_drop_inode(struct inode *inode);
|
2007-06-12 10:35:45 +00:00
|
|
|
int btrfs_init_cachep(void);
|
|
|
|
void btrfs_destroy_cachep(void);
|
2008-06-10 14:07:39 +00:00
|
|
|
long btrfs_ioctl_trans_end(struct file *file);
|
2008-07-20 20:31:04 +00:00
|
|
|
struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
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|
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struct btrfs_root *root);
|
2007-06-12 10:35:45 +00:00
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|
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int btrfs_commit_write(struct file *file, struct page *page,
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|
|
|
unsigned from, unsigned to);
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2007-08-27 20:49:44 +00:00
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struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
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size_t page_offset, u64 start, u64 end,
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|
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int create);
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|
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int btrfs_update_inode(struct btrfs_trans_handle *trans,
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struct btrfs_root *root,
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|
|
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struct inode *inode);
|
2008-09-26 14:05:38 +00:00
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int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode);
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int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode);
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void btrfs_orphan_cleanup(struct btrfs_root *root);
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2008-10-30 18:19:41 +00:00
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int btrfs_cont_expand(struct inode *inode, loff_t size);
|
2009-09-21 20:00:26 +00:00
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int btrfs_invalidate_inodes(struct btrfs_root *root);
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2009-10-09 13:54:36 +00:00
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|
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extern const struct dentry_operations btrfs_dentry_operations;
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2008-06-12 01:53:53 +00:00
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|
|
|
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/* ioctl.c */
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long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
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2009-04-17 08:37:41 +00:00
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|
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void btrfs_update_iflags(struct inode *inode);
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void btrfs_inherit_iflags(struct inode *inode, struct inode *dir);
|
2008-06-12 01:53:53 +00:00
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|
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2007-06-12 10:35:45 +00:00
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|
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/* file.c */
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2008-09-05 20:13:11 +00:00
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int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync);
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2008-09-26 14:05:38 +00:00
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|
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int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
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|
|
|
int skip_pinned);
|
2008-01-22 21:47:59 +00:00
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|
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int btrfs_check_file(struct btrfs_root *root, struct inode *inode);
|
2009-10-01 22:43:56 +00:00
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|
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extern const struct file_operations btrfs_file_operations;
|
2007-06-12 10:35:45 +00:00
|
|
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int btrfs_drop_extents(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct inode *inode,
|
2009-04-24 18:39:24 +00:00
|
|
|
u64 start, u64 end, u64 locked_end,
|
2009-09-11 16:27:37 +00:00
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|
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u64 inline_limit, u64 *hint_block, int drop_cache);
|
2008-10-30 18:25:28 +00:00
|
|
|
int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
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|
|
struct btrfs_root *root,
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|
|
|
struct inode *inode, u64 start, u64 end);
|
2008-06-10 14:07:39 +00:00
|
|
|
int btrfs_release_file(struct inode *inode, struct file *file);
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|
|
2007-08-07 20:15:09 +00:00
|
|
|
/* tree-defrag.c */
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|
|
|
int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
|
|
|
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struct btrfs_root *root, int cache_only);
|
2007-08-29 19:47:34 +00:00
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|
|
|
|
|
/* sysfs.c */
|
|
|
|
int btrfs_init_sysfs(void);
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void btrfs_exit_sysfs(void);
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|
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int btrfs_sysfs_add_super(struct btrfs_fs_info *fs);
|
|
|
|
int btrfs_sysfs_add_root(struct btrfs_root *root);
|
|
|
|
void btrfs_sysfs_del_root(struct btrfs_root *root);
|
|
|
|
void btrfs_sysfs_del_super(struct btrfs_fs_info *root);
|
|
|
|
|
2007-11-16 16:45:54 +00:00
|
|
|
/* xattr.c */
|
|
|
|
ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size);
|
2008-07-24 16:16:03 +00:00
|
|
|
|
2007-12-21 21:27:24 +00:00
|
|
|
/* super.c */
|
|
|
|
u64 btrfs_parse_size(char *str);
|
2008-06-10 14:40:29 +00:00
|
|
|
int btrfs_parse_options(struct btrfs_root *root, char *options);
|
2008-06-10 14:07:39 +00:00
|
|
|
int btrfs_sync_fs(struct super_block *sb, int wait);
|
2008-07-24 16:16:36 +00:00
|
|
|
|
|
|
|
/* acl.c */
|
2009-10-13 17:50:18 +00:00
|
|
|
#ifdef CONFIG_BTRFS_FS_POSIX_ACL
|
2008-07-24 16:16:36 +00:00
|
|
|
int btrfs_check_acl(struct inode *inode, int mask);
|
2009-06-10 15:36:43 +00:00
|
|
|
#else
|
|
|
|
#define btrfs_check_acl NULL
|
|
|
|
#endif
|
2008-07-24 16:16:36 +00:00
|
|
|
int btrfs_init_acl(struct inode *inode, struct inode *dir);
|
|
|
|
int btrfs_acl_chmod(struct inode *inode);
|
Btrfs: free space accounting redo
1) replace the per fs_info extent_io_tree that tracked free space with two
rb-trees per block group to track free space areas via offset and size. The
reason to do this is because most allocations come with a hint byte where to
start, so we can usually find a chunk of free space at that hint byte to satisfy
the allocation and get good space packing. If we cannot find free space at or
after the given offset we fall back on looking for a chunk of the given size as
close to that given offset as possible. When we fall back on the size search we
also try to find a slot as close to the size we want as possible, to avoid
breaking small chunks off of huge areas if possible.
2) remove the extent_io_tree that tracked the block group cache from fs_info and
replaced it with an rb-tree thats tracks block group cache via offset. also
added a per space_info list that tracks the block group cache for the particular
space so we can lookup related block groups easily.
3) cleaned up the allocation code to make it a little easier to read and a
little less complicated. Basically there are 3 steps, first look from our
provided hint. If we couldn't find from that given hint, start back at our
original search start and look for space from there. If that fails try to
allocate space if we can and start looking again. If not we're screwed and need
to start over again.
4) small fixes. there were some issues in volumes.c where we wouldn't allocate
the rest of the disk. fixed cow_file_range to actually pass the alloc_hint,
which has helped a good bit in making the fs_mark test I run have semi-normal
results as we run out of space. Generally with data allocations we don't track
where we last allocated from, so everytime we did a data allocation we'd search
through every block group that we have looking for free space. Now searching a
block group with no free space isn't terribly time consuming, it was causing a
slight degradation as we got more data block groups. The alloc_hint has fixed
this slight degredation and made things semi-normal.
There is still one nagging problem I'm working on where we will get ENOSPC when
there is definitely plenty of space. This only happens with metadata
allocations, and only when we are almost full. So you generally hit the 85%
mark first, but sometimes you'll hit the BUG before you hit the 85% wall. I'm
still tracking it down, but until then this seems to be pretty stable and make a
significant performance gain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-09-23 17:14:11 +00:00
|
|
|
|
Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 14:45:14 +00:00
|
|
|
/* relocation.c */
|
|
|
|
int btrfs_relocate_block_group(struct btrfs_root *root, u64 group_start);
|
|
|
|
int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root);
|
|
|
|
int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
|
|
|
|
struct btrfs_root *root);
|
|
|
|
int btrfs_recover_relocation(struct btrfs_root *root);
|
|
|
|
int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len);
|
2007-02-02 14:18:22 +00:00
|
|
|
#endif
|