linux/fs/btrfs/file.c

1336 lines
36 KiB
C
Raw Normal View History

/*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License v2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 021110-1307, USA.
*/
#include <linux/fs.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/backing-dev.h>
#include <linux/mpage.h>
#include <linux/swap.h>
#include <linux/writeback.h>
#include <linux/statfs.h>
#include <linux/compat.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#include "btrfs_inode.h"
#include "ioctl.h"
#include "print-tree.h"
#include "tree-log.h"
#include "locking.h"
Btrfs: Add workaround for AppArmor changing remove_suid() In openSUSE 10.3, AppArmor modifies remove_suid to take a struct path rather than just a dentry. This patch tests that the kernel is openSUSE 10.3 or newer and adjusts the call accordingly. Debian/Ubuntu with AppArmor applied will also need a similar patch. Maintainers of btrfs under those distributions should build on this patch or, alternatively, alter their package descriptions to add -DREMOVE_SUID_PATH to the compiler command line. Signed-off-by: Jeff Mahoney <jeffm@suse.com> - --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ b/compat.h 2008-02-06 16:46:13.000000000 -0500 @@ -0,0 +1,15 @@ +#ifndef _COMPAT_H_ +#define _COMPAT_H_ + + +/* + * Even if AppArmor isn't enabled, it still has different prototypes. + * Add more distro/version pairs here to declare which has AppArmor applied. + */ +#if defined(CONFIG_SUSE_KERNEL) +# if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,22) +# define REMOVE_SUID_PATH 1 +# endif +#endif + +#endif /* _COMPAT_H_ */ - --- a/file.c 2008-02-06 11:37:39.000000000 -0500 +++ b/file.c 2008-02-06 16:46:23.000000000 -0500 @@ -37,6 +37,7 @@ #include "ordered-data.h" #include "ioctl.h" #include "print-tree.h" +#include "compat.h" static int btrfs_copy_from_user(loff_t pos, int num_pages, int write_bytes, @@ -790,7 +791,11 @@ static ssize_t btrfs_file_write(struct f goto out_nolock; if (count == 0) goto out_nolock; +#ifdef REMOVE_SUID_PATH + err = remove_suid(&file->f_path); +#else err = remove_suid(fdentry(file)); +#endif if (err) goto out_nolock; file_update_time(file); Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-05-02 19:03:58 +00:00
#include "compat.h"
/* simple helper to fault in pages and copy. This should go away
* and be replaced with calls into generic code.
*/
static noinline int btrfs_copy_from_user(loff_t pos, int num_pages,
int write_bytes,
struct page **prepared_pages,
const char __user *buf)
{
long page_fault = 0;
int i;
int offset = pos & (PAGE_CACHE_SIZE - 1);
for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
size_t count = min_t(size_t,
PAGE_CACHE_SIZE - offset, write_bytes);
struct page *page = prepared_pages[i];
fault_in_pages_readable(buf, count);
/* Copy data from userspace to the current page */
kmap(page);
page_fault = __copy_from_user(page_address(page) + offset,
buf, count);
/* Flush processor's dcache for this page */
flush_dcache_page(page);
kunmap(page);
buf += count;
write_bytes -= count;
if (page_fault)
break;
}
return page_fault ? -EFAULT : 0;
}
/*
* unlocks pages after btrfs_file_write is done with them
*/
static noinline void btrfs_drop_pages(struct page **pages, size_t num_pages)
{
size_t i;
for (i = 0; i < num_pages; i++) {
if (!pages[i])
break;
/* page checked is some magic around finding pages that
* have been modified without going through btrfs_set_page_dirty
* clear it here
*/
ClearPageChecked(pages[i]);
unlock_page(pages[i]);
mark_page_accessed(pages[i]);
page_cache_release(pages[i]);
}
}
/*
* after copy_from_user, pages need to be dirtied and we need to make
* sure holes are created between the current EOF and the start of
* any next extents (if required).
*
* this also makes the decision about creating an inline extent vs
* doing real data extents, marking pages dirty and delalloc as required.
*/
static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct file *file,
struct page **pages,
size_t num_pages,
loff_t pos,
size_t write_bytes)
{
int err = 0;
int i;
struct inode *inode = fdentry(file)->d_inode;
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
u64 hint_byte;
u64 num_bytes;
u64 start_pos;
u64 end_of_last_block;
u64 end_pos = pos + write_bytes;
loff_t isize = i_size_read(inode);
start_pos = pos & ~((u64)root->sectorsize - 1);
num_bytes = (write_bytes + pos - start_pos +
root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
end_of_last_block = start_pos + num_bytes - 1;
lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
trans = btrfs_join_transaction(root, 1);
if (!trans) {
err = -ENOMEM;
goto out_unlock;
}
btrfs_set_trans_block_group(trans, inode);
hint_byte = 0;
set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
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
/* check for reserved extents on each page, we don't want
* to reset the delalloc bit on things that already have
* extents reserved.
*/
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_set_extent_delalloc(inode, start_pos, end_of_last_block);
for (i = 0; i < num_pages; i++) {
struct page *p = pages[i];
SetPageUptodate(p);
ClearPageChecked(p);
set_page_dirty(p);
}
if (end_pos > isize) {
i_size_write(inode, end_pos);
btrfs_update_inode(trans, root, inode);
}
err = btrfs_end_transaction(trans, root);
out_unlock:
unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
return err;
}
/*
* this drops all the extents in the cache that intersect the range
* [start, end]. Existing extents are split as required.
*/
int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
int skip_pinned)
{
struct extent_map *em;
struct extent_map *split = NULL;
struct extent_map *split2 = NULL;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
u64 len = end - start + 1;
int ret;
int testend = 1;
unsigned long 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
int compressed = 0;
WARN_ON(end < start);
if (end == (u64)-1) {
len = (u64)-1;
testend = 0;
}
while (1) {
if (!split)
split = alloc_extent_map(GFP_NOFS);
if (!split2)
split2 = alloc_extent_map(GFP_NOFS);
spin_lock(&em_tree->lock);
em = lookup_extent_mapping(em_tree, start, len);
if (!em) {
spin_unlock(&em_tree->lock);
break;
}
flags = em->flags;
if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
spin_unlock(&em_tree->lock);
if (em->start <= start &&
(!testend || em->start + em->len >= start + len)) {
free_extent_map(em);
break;
}
if (start < em->start) {
len = em->start - start;
} else {
len = start + len - (em->start + em->len);
start = em->start + em->len;
}
free_extent_map(em);
continue;
}
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
compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
clear_bit(EXTENT_FLAG_PINNED, &em->flags);
remove_extent_mapping(em_tree, em);
if (em->block_start < EXTENT_MAP_LAST_BYTE &&
em->start < start) {
split->start = em->start;
split->len = start - em->start;
split->orig_start = em->orig_start;
split->block_start = em->block_start;
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
if (compressed)
split->block_len = em->block_len;
else
split->block_len = split->len;
split->bdev = em->bdev;
split->flags = flags;
ret = add_extent_mapping(em_tree, split);
BUG_ON(ret);
free_extent_map(split);
split = split2;
split2 = NULL;
}
if (em->block_start < EXTENT_MAP_LAST_BYTE &&
testend && em->start + em->len > start + len) {
u64 diff = start + len - em->start;
split->start = start + len;
split->len = em->start + em->len - (start + len);
split->bdev = em->bdev;
split->flags = 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
if (compressed) {
split->block_len = em->block_len;
split->block_start = em->block_start;
split->orig_start = em->orig_start;
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
} else {
split->block_len = split->len;
split->block_start = em->block_start + diff;
split->orig_start = split->start;
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
}
ret = add_extent_mapping(em_tree, split);
BUG_ON(ret);
free_extent_map(split);
split = NULL;
}
spin_unlock(&em_tree->lock);
/* once for us */
free_extent_map(em);
/* once for the tree*/
free_extent_map(em);
}
if (split)
free_extent_map(split);
if (split2)
free_extent_map(split2);
return 0;
}
int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
{
return 0;
#if 0
struct btrfs_path *path;
struct btrfs_key found_key;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *extent;
u64 last_offset = 0;
int nritems;
int slot;
int found_type;
int ret;
int err = 0;
u64 extent_end = 0;
path = btrfs_alloc_path();
ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
last_offset, 0);
while (1) {
nritems = btrfs_header_nritems(path->nodes[0]);
if (path->slots[0] >= nritems) {
ret = btrfs_next_leaf(root, path);
if (ret)
goto out;
nritems = btrfs_header_nritems(path->nodes[0]);
}
slot = path->slots[0];
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &found_key, slot);
if (found_key.objectid != inode->i_ino)
break;
if (found_key.type != BTRFS_EXTENT_DATA_KEY)
goto out;
if (found_key.offset < last_offset) {
WARN_ON(1);
btrfs_print_leaf(root, leaf);
printk(KERN_ERR "inode %lu found offset %llu "
"expected %llu\n", inode->i_ino,
(unsigned long long)found_key.offset,
(unsigned long long)last_offset);
err = 1;
goto out;
}
extent = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(leaf, extent);
if (found_type == BTRFS_FILE_EXTENT_REG) {
extent_end = found_key.offset +
btrfs_file_extent_num_bytes(leaf, extent);
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
struct btrfs_item *item;
item = btrfs_item_nr(leaf, slot);
extent_end = found_key.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
btrfs_file_extent_inline_len(leaf, extent);
extent_end = (extent_end + root->sectorsize - 1) &
~((u64)root->sectorsize - 1);
}
last_offset = extent_end;
path->slots[0]++;
}
if (0 && last_offset < inode->i_size) {
WARN_ON(1);
btrfs_print_leaf(root, leaf);
printk(KERN_ERR "inode %lu found offset %llu size %llu\n",
inode->i_ino, (unsigned long long)last_offset,
(unsigned long long)inode->i_size);
err = 1;
}
out:
btrfs_free_path(path);
return err;
#endif
}
/*
* this is very complex, but the basic idea is to drop all extents
* in the range start - end. hint_block is filled in with a block number
* that would be a good hint to the block allocator for this file.
*
* If an extent intersects the range but is not entirely inside the range
* it is either truncated or split. Anything entirely inside the range
* is deleted from the tree.
*
* inline_limit is used to tell this code which offsets in the file to keep
* if they contain inline extents.
*/
noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
struct btrfs_root *root, struct inode *inode,
u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
{
u64 extent_end = 0;
u64 locked_end = end;
u64 search_start = start;
u64 leaf_start;
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
u64 ram_bytes = 0;
u64 orig_parent = 0;
u64 disk_bytenr = 0;
u8 compression;
u8 encryption;
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
u16 other_encoding = 0;
u64 root_gen;
u64 root_owner;
struct extent_buffer *leaf;
struct btrfs_file_extent_item *extent;
struct btrfs_path *path;
struct btrfs_key key;
struct btrfs_file_extent_item old;
int keep;
int slot;
int bookend;
int found_type = 0;
int found_extent;
int found_inline;
int recow;
int ret;
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
inline_limit = 0;
btrfs_drop_extent_cache(inode, start, end - 1, 0);
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
while (1) {
recow = 0;
btrfs_release_path(root, path);
ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
search_start, -1);
if (ret < 0)
goto out;
if (ret > 0) {
if (path->slots[0] == 0) {
ret = 0;
goto out;
}
path->slots[0]--;
}
next_slot:
keep = 0;
bookend = 0;
found_extent = 0;
found_inline = 0;
leaf_start = 0;
root_gen = 0;
root_owner = 0;
compression = 0;
encryption = 0;
extent = NULL;
leaf = path->nodes[0];
slot = path->slots[0];
ret = 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
key.offset >= end) {
goto out;
}
if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
key.objectid != inode->i_ino) {
goto out;
}
if (recow) {
search_start = max(key.offset, start);
continue;
}
if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
extent = btrfs_item_ptr(leaf, slot,
struct btrfs_file_extent_item);
found_type = btrfs_file_extent_type(leaf, extent);
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
compression = btrfs_file_extent_compression(leaf,
extent);
encryption = btrfs_file_extent_encryption(leaf,
extent);
other_encoding = btrfs_file_extent_other_encoding(leaf,
extent);
if (found_type == BTRFS_FILE_EXTENT_REG ||
found_type == BTRFS_FILE_EXTENT_PREALLOC) {
extent_end =
btrfs_file_extent_disk_bytenr(leaf,
extent);
if (extent_end)
*hint_byte = extent_end;
extent_end = key.offset +
btrfs_file_extent_num_bytes(leaf, extent);
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
ram_bytes = btrfs_file_extent_ram_bytes(leaf,
extent);
found_extent = 1;
} else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
found_inline = 1;
extent_end = key.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
btrfs_file_extent_inline_len(leaf, extent);
}
} else {
extent_end = search_start;
}
/* we found nothing we can drop */
if ((!found_extent && !found_inline) ||
search_start >= extent_end) {
int nextret;
u32 nritems;
nritems = btrfs_header_nritems(leaf);
if (slot >= nritems - 1) {
nextret = btrfs_next_leaf(root, path);
if (nextret)
goto out;
recow = 1;
} else {
path->slots[0]++;
}
goto next_slot;
}
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
if (end <= extent_end && start >= key.offset && found_inline)
*hint_byte = EXTENT_MAP_INLINE;
if (found_extent) {
read_extent_buffer(leaf, &old, (unsigned long)extent,
sizeof(old));
root_gen = btrfs_header_generation(leaf);
root_owner = btrfs_header_owner(leaf);
leaf_start = leaf->start;
}
if (end < extent_end && end >= key.offset) {
bookend = 1;
if (found_inline && start <= key.offset)
keep = 1;
}
if (bookend && found_extent) {
if (locked_end < extent_end) {
ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
locked_end, extent_end - 1,
GFP_NOFS);
if (!ret) {
btrfs_release_path(root, path);
lock_extent(&BTRFS_I(inode)->io_tree,
locked_end, extent_end - 1,
GFP_NOFS);
locked_end = extent_end;
continue;
}
locked_end = extent_end;
}
orig_parent = path->nodes[0]->start;
disk_bytenr = le64_to_cpu(old.disk_bytenr);
if (disk_bytenr != 0) {
ret = btrfs_inc_extent_ref(trans, root,
disk_bytenr,
le64_to_cpu(old.disk_num_bytes),
orig_parent, root->root_key.objectid,
trans->transid, inode->i_ino);
BUG_ON(ret);
}
}
if (found_inline) {
u64 mask = root->sectorsize - 1;
search_start = (extent_end + mask) & ~mask;
} else
search_start = extent_end;
/* truncate existing extent */
if (start > key.offset) {
u64 new_num;
u64 old_num;
keep = 1;
WARN_ON(start & (root->sectorsize - 1));
if (found_extent) {
new_num = start - key.offset;
old_num = btrfs_file_extent_num_bytes(leaf,
extent);
*hint_byte =
btrfs_file_extent_disk_bytenr(leaf,
extent);
if (btrfs_file_extent_disk_bytenr(leaf,
extent)) {
inode_sub_bytes(inode, old_num -
new_num);
}
btrfs_set_file_extent_num_bytes(leaf,
extent, new_num);
btrfs_mark_buffer_dirty(leaf);
} else if (key.offset < inline_limit &&
(end > extent_end) &&
(inline_limit < extent_end)) {
u32 new_size;
new_size = btrfs_file_extent_calc_inline_size(
inline_limit - key.offset);
inode_sub_bytes(inode, extent_end -
inline_limit);
btrfs_set_file_extent_ram_bytes(leaf, extent,
new_size);
if (!compression && !encryption) {
btrfs_truncate_item(trans, root, path,
new_size, 1);
}
}
}
/* delete the entire extent */
if (!keep) {
if (found_inline)
inode_sub_bytes(inode, extent_end -
key.offset);
ret = btrfs_del_item(trans, root, path);
/* TODO update progress marker and return */
BUG_ON(ret);
extent = NULL;
btrfs_release_path(root, path);
/* the extent will be freed later */
}
if (bookend && found_inline && start <= key.offset) {
u32 new_size;
new_size = btrfs_file_extent_calc_inline_size(
extent_end - end);
inode_sub_bytes(inode, end - key.offset);
btrfs_set_file_extent_ram_bytes(leaf, extent,
new_size);
if (!compression && !encryption)
ret = btrfs_truncate_item(trans, root, path,
new_size, 0);
BUG_ON(ret);
}
/* create bookend, splitting the extent in two */
if (bookend && found_extent) {
struct btrfs_key ins;
ins.objectid = inode->i_ino;
ins.offset = end;
btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
btrfs_release_path(root, path);
path->leave_spinning = 1;
ret = btrfs_insert_empty_item(trans, root, path, &ins,
sizeof(*extent));
BUG_ON(ret);
leaf = path->nodes[0];
extent = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
write_extent_buffer(leaf, &old,
(unsigned long)extent, sizeof(old));
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_set_file_extent_compression(leaf, extent,
compression);
btrfs_set_file_extent_encryption(leaf, extent,
encryption);
btrfs_set_file_extent_other_encoding(leaf, extent,
other_encoding);
btrfs_set_file_extent_offset(leaf, extent,
le64_to_cpu(old.offset) + end - key.offset);
WARN_ON(le64_to_cpu(old.num_bytes) <
(extent_end - end));
btrfs_set_file_extent_num_bytes(leaf, extent,
extent_end - end);
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
/*
* set the ram bytes to the size of the full extent
* before splitting. This is a worst case flag,
* but its the best we can do because we don't know
* how splitting affects compression
*/
btrfs_set_file_extent_ram_bytes(leaf, extent,
ram_bytes);
btrfs_set_file_extent_type(leaf, extent, found_type);
btrfs_unlock_up_safe(path, 1);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_set_lock_blocking(path->nodes[0]);
if (disk_bytenr != 0) {
ret = btrfs_update_extent_ref(trans, root,
Btrfs: do extent allocation and reference count updates in the background The extent allocation tree maintains a reference count and full back reference information for every extent allocated in the filesystem. For subvolume and snapshot trees, every time a block goes through COW, the new copy of the block adds a reference on every block it points to. If a btree node points to 150 leaves, then the COW code needs to go and add backrefs on 150 different extents, which might be spread all over the extent allocation tree. These updates currently happen during btrfs_cow_block, and most COWs happen during btrfs_search_slot. btrfs_search_slot has locks held on both the parent and the node we are COWing, and so we really want to avoid IO during the COW if we can. This commit adds an rbtree of pending reference count updates and extent allocations. The tree is ordered by byte number of the extent and byte number of the parent for the back reference. The tree allows us to: 1) Modify back references in something close to disk order, reducing seeks 2) Significantly reduce the number of modifications made as block pointers are balanced around 3) Do all of the extent insertion and back reference modifications outside of the performance critical btrfs_search_slot code. #3 has the added benefit of greatly reducing the btrfs stack footprint. The extent allocation tree modifications are done without the deep (and somewhat recursive) call chains used in the past. These delayed back reference updates must be done before the transaction commits, and so the rbtree is tied to the transaction. Throttling is implemented to help keep the queue of backrefs at a reasonable size. Since there was a similar mechanism in place for the extent tree extents, that is removed and replaced by the delayed reference tree. Yan Zheng <yan.zheng@oracle.com> helped review and fixup this code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-13 14:10:06 +00:00
disk_bytenr,
le64_to_cpu(old.disk_num_bytes),
orig_parent,
leaf->start,
root->root_key.objectid,
trans->transid, ins.objectid);
BUG_ON(ret);
}
path->leave_spinning = 0;
btrfs_release_path(root, path);
if (disk_bytenr != 0)
inode_add_bytes(inode, extent_end - end);
}
if (found_extent && !keep) {
u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
if (old_disk_bytenr != 0) {
inode_sub_bytes(inode,
le64_to_cpu(old.num_bytes));
ret = btrfs_free_extent(trans, root,
old_disk_bytenr,
le64_to_cpu(old.disk_num_bytes),
leaf_start, root_owner,
root_gen, key.objectid, 0);
BUG_ON(ret);
*hint_byte = old_disk_bytenr;
}
}
if (search_start >= end) {
ret = 0;
goto out;
}
}
out:
btrfs_free_path(path);
if (locked_end > end) {
unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
GFP_NOFS);
}
btrfs_check_file(root, inode);
return ret;
}
static int extent_mergeable(struct extent_buffer *leaf, int slot,
u64 objectid, u64 bytenr, u64 *start, u64 *end)
{
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
u64 extent_end;
if (slot < 0 || slot >= btrfs_header_nritems(leaf))
return 0;
btrfs_item_key_to_cpu(leaf, &key, slot);
if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
return 0;
fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
btrfs_file_extent_compression(leaf, fi) ||
btrfs_file_extent_encryption(leaf, fi) ||
btrfs_file_extent_other_encoding(leaf, fi))
return 0;
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
if ((*start && *start != key.offset) || (*end && *end != extent_end))
return 0;
*start = key.offset;
*end = extent_end;
return 1;
}
/*
* Mark extent in the range start - end as written.
*
* This changes extent type from 'pre-allocated' to 'regular'. If only
* part of extent is marked as written, the extent will be split into
* two or three.
*/
int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct inode *inode, u64 start, u64 end)
{
struct extent_buffer *leaf;
struct btrfs_path *path;
struct btrfs_file_extent_item *fi;
struct btrfs_key key;
u64 bytenr;
u64 num_bytes;
u64 extent_end;
u64 extent_offset;
u64 other_start;
u64 other_end;
u64 split = start;
u64 locked_end = end;
u64 orig_parent;
int extent_type;
int split_end = 1;
int ret;
btrfs_drop_extent_cache(inode, start, end - 1, 0);
path = btrfs_alloc_path();
BUG_ON(!path);
again:
key.objectid = inode->i_ino;
key.type = BTRFS_EXTENT_DATA_KEY;
if (split == start)
key.offset = split;
else
key.offset = split - 1;
ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
if (ret > 0 && path->slots[0] > 0)
path->slots[0]--;
leaf = path->nodes[0];
btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
BUG_ON(key.objectid != inode->i_ino ||
key.type != BTRFS_EXTENT_DATA_KEY);
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
extent_type = btrfs_file_extent_type(leaf, fi);
BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
BUG_ON(key.offset > start || extent_end < end);
bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
extent_offset = btrfs_file_extent_offset(leaf, fi);
if (key.offset == start)
split = end;
if (key.offset == start && extent_end == end) {
int del_nr = 0;
int del_slot = 0;
u64 leaf_owner = btrfs_header_owner(leaf);
u64 leaf_gen = btrfs_header_generation(leaf);
other_start = end;
other_end = 0;
if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
bytenr, &other_start, &other_end)) {
extent_end = other_end;
del_slot = path->slots[0] + 1;
del_nr++;
ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
leaf->start, leaf_owner,
leaf_gen, inode->i_ino, 0);
BUG_ON(ret);
}
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
bytenr, &other_start, &other_end)) {
key.offset = other_start;
del_slot = path->slots[0];
del_nr++;
ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
leaf->start, leaf_owner,
leaf_gen, inode->i_ino, 0);
BUG_ON(ret);
}
split_end = 0;
if (del_nr == 0) {
btrfs_set_file_extent_type(leaf, fi,
BTRFS_FILE_EXTENT_REG);
goto done;
}
fi = btrfs_item_ptr(leaf, del_slot - 1,
struct btrfs_file_extent_item);
btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
btrfs_set_file_extent_num_bytes(leaf, fi,
extent_end - key.offset);
btrfs_mark_buffer_dirty(leaf);
ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
BUG_ON(ret);
goto done;
} else if (split == start) {
if (locked_end < extent_end) {
ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
locked_end, extent_end - 1, GFP_NOFS);
if (!ret) {
btrfs_release_path(root, path);
lock_extent(&BTRFS_I(inode)->io_tree,
locked_end, extent_end - 1, GFP_NOFS);
locked_end = extent_end;
goto again;
}
locked_end = extent_end;
}
btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
extent_offset += split - key.offset;
} else {
BUG_ON(key.offset != start);
btrfs_set_file_extent_offset(leaf, fi, extent_offset +
split - key.offset);
btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
key.offset = split;
btrfs_set_item_key_safe(trans, root, path, &key);
extent_end = split;
}
if (extent_end == end) {
split_end = 0;
extent_type = BTRFS_FILE_EXTENT_REG;
}
if (extent_end == end && split == start) {
other_start = end;
other_end = 0;
if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
bytenr, &other_start, &other_end)) {
path->slots[0]++;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
key.offset = split;
btrfs_set_item_key_safe(trans, root, path, &key);
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi,
other_end - split);
goto done;
}
}
if (extent_end == end && split == end) {
other_start = 0;
other_end = start;
if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
bytenr, &other_start, &other_end)) {
path->slots[0]--;
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
other_start);
goto done;
}
}
btrfs_mark_buffer_dirty(leaf);
orig_parent = leaf->start;
ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
orig_parent, root->root_key.objectid,
trans->transid, inode->i_ino);
BUG_ON(ret);
btrfs_release_path(root, path);
key.offset = start;
ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
BUG_ON(ret);
leaf = path->nodes[0];
fi = btrfs_item_ptr(leaf, path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_generation(leaf, fi, trans->transid);
btrfs_set_file_extent_type(leaf, fi, extent_type);
btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_offset(leaf, fi, extent_offset);
btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
btrfs_set_file_extent_compression(leaf, fi, 0);
btrfs_set_file_extent_encryption(leaf, fi, 0);
btrfs_set_file_extent_other_encoding(leaf, fi, 0);
if (orig_parent != leaf->start) {
Btrfs: do extent allocation and reference count updates in the background The extent allocation tree maintains a reference count and full back reference information for every extent allocated in the filesystem. For subvolume and snapshot trees, every time a block goes through COW, the new copy of the block adds a reference on every block it points to. If a btree node points to 150 leaves, then the COW code needs to go and add backrefs on 150 different extents, which might be spread all over the extent allocation tree. These updates currently happen during btrfs_cow_block, and most COWs happen during btrfs_search_slot. btrfs_search_slot has locks held on both the parent and the node we are COWing, and so we really want to avoid IO during the COW if we can. This commit adds an rbtree of pending reference count updates and extent allocations. The tree is ordered by byte number of the extent and byte number of the parent for the back reference. The tree allows us to: 1) Modify back references in something close to disk order, reducing seeks 2) Significantly reduce the number of modifications made as block pointers are balanced around 3) Do all of the extent insertion and back reference modifications outside of the performance critical btrfs_search_slot code. #3 has the added benefit of greatly reducing the btrfs stack footprint. The extent allocation tree modifications are done without the deep (and somewhat recursive) call chains used in the past. These delayed back reference updates must be done before the transaction commits, and so the rbtree is tied to the transaction. Throttling is implemented to help keep the queue of backrefs at a reasonable size. Since there was a similar mechanism in place for the extent tree extents, that is removed and replaced by the delayed reference tree. Yan Zheng <yan.zheng@oracle.com> helped review and fixup this code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-13 14:10:06 +00:00
ret = btrfs_update_extent_ref(trans, root, bytenr, num_bytes,
orig_parent, leaf->start,
root->root_key.objectid,
trans->transid, inode->i_ino);
BUG_ON(ret);
}
done:
btrfs_mark_buffer_dirty(leaf);
btrfs_release_path(root, path);
if (split_end && split == start) {
split = end;
goto again;
}
if (locked_end > end) {
unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
GFP_NOFS);
}
btrfs_free_path(path);
return 0;
}
/*
* this gets pages into the page cache and locks them down, it also properly
* waits for data=ordered extents to finish before allowing the pages to be
* modified.
*/
static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
struct page **pages, size_t num_pages,
loff_t pos, unsigned long first_index,
unsigned long last_index, size_t write_bytes)
{
int i;
unsigned long index = pos >> PAGE_CACHE_SHIFT;
struct inode *inode = fdentry(file)->d_inode;
int err = 0;
u64 start_pos;
u64 last_pos;
start_pos = pos & ~((u64)root->sectorsize - 1);
last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
if (start_pos > inode->i_size) {
err = btrfs_cont_expand(inode, start_pos);
if (err)
return err;
}
memset(pages, 0, num_pages * sizeof(struct page *));
again:
for (i = 0; i < num_pages; i++) {
pages[i] = grab_cache_page(inode->i_mapping, index + i);
if (!pages[i]) {
err = -ENOMEM;
BUG_ON(1);
}
wait_on_page_writeback(pages[i]);
}
if (start_pos < inode->i_size) {
struct btrfs_ordered_extent *ordered;
lock_extent(&BTRFS_I(inode)->io_tree,
start_pos, last_pos - 1, GFP_NOFS);
ordered = btrfs_lookup_first_ordered_extent(inode,
last_pos - 1);
if (ordered &&
ordered->file_offset + ordered->len > start_pos &&
ordered->file_offset < last_pos) {
btrfs_put_ordered_extent(ordered);
unlock_extent(&BTRFS_I(inode)->io_tree,
start_pos, last_pos - 1, GFP_NOFS);
for (i = 0; i < num_pages; i++) {
unlock_page(pages[i]);
page_cache_release(pages[i]);
}
btrfs_wait_ordered_range(inode, start_pos,
last_pos - start_pos);
goto again;
}
if (ordered)
btrfs_put_ordered_extent(ordered);
clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
GFP_NOFS);
unlock_extent(&BTRFS_I(inode)->io_tree,
start_pos, last_pos - 1, GFP_NOFS);
}
for (i = 0; i < num_pages; i++) {
clear_page_dirty_for_io(pages[i]);
set_page_extent_mapped(pages[i]);
WARN_ON(!PageLocked(pages[i]));
}
return 0;
}
static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
loff_t pos;
loff_t start_pos;
ssize_t num_written = 0;
ssize_t err = 0;
int ret = 0;
struct inode *inode = fdentry(file)->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
struct page **pages = NULL;
int nrptrs;
struct page *pinned[2];
unsigned long first_index;
unsigned long last_index;
int will_write;
will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
(file->f_flags & O_DIRECT));
nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
PAGE_CACHE_SIZE / (sizeof(struct page *)));
pinned[0] = NULL;
pinned[1] = NULL;
pos = *ppos;
start_pos = pos;
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
current->backing_dev_info = inode->i_mapping->backing_dev_info;
err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
if (err)
goto out_nolock;
if (count == 0)
goto out_nolock;
err = file_remove_suid(file);
if (err)
goto out_nolock;
file_update_time(file);
pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
mutex_lock(&inode->i_mutex);
BTRFS_I(inode)->sequence++;
first_index = pos >> PAGE_CACHE_SHIFT;
last_index = (pos + count) >> PAGE_CACHE_SHIFT;
/*
* there are lots of better ways to do this, but this code
* makes sure the first and last page in the file range are
* up to date and ready for cow
*/
if ((pos & (PAGE_CACHE_SIZE - 1))) {
pinned[0] = grab_cache_page(inode->i_mapping, first_index);
if (!PageUptodate(pinned[0])) {
ret = btrfs_readpage(NULL, pinned[0]);
BUG_ON(ret);
wait_on_page_locked(pinned[0]);
} else {
unlock_page(pinned[0]);
}
}
if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
pinned[1] = grab_cache_page(inode->i_mapping, last_index);
if (!PageUptodate(pinned[1])) {
ret = btrfs_readpage(NULL, pinned[1]);
BUG_ON(ret);
wait_on_page_locked(pinned[1]);
} else {
unlock_page(pinned[1]);
}
}
while (count > 0) {
size_t offset = pos & (PAGE_CACHE_SIZE - 1);
size_t write_bytes = min(count, nrptrs *
(size_t)PAGE_CACHE_SIZE -
offset);
size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT;
WARN_ON(num_pages > nrptrs);
memset(pages, 0, sizeof(struct page *) * nrptrs);
ret = btrfs_check_data_free_space(root, inode, write_bytes);
if (ret)
goto out;
ret = prepare_pages(root, file, pages, num_pages,
pos, first_index, last_index,
write_bytes);
if (ret) {
btrfs_free_reserved_data_space(root, inode,
write_bytes);
goto out;
}
ret = btrfs_copy_from_user(pos, num_pages,
write_bytes, pages, buf);
if (ret) {
btrfs_free_reserved_data_space(root, inode,
write_bytes);
btrfs_drop_pages(pages, num_pages);
goto out;
}
ret = dirty_and_release_pages(NULL, root, file, pages,
num_pages, pos, write_bytes);
btrfs_drop_pages(pages, num_pages);
if (ret) {
btrfs_free_reserved_data_space(root, inode,
write_bytes);
goto out;
}
if (will_write) {
btrfs_fdatawrite_range(inode->i_mapping, pos,
pos + write_bytes - 1,
WB_SYNC_NONE);
} else {
balance_dirty_pages_ratelimited_nr(inode->i_mapping,
num_pages);
if (num_pages <
(root->leafsize >> PAGE_CACHE_SHIFT) + 1)
btrfs_btree_balance_dirty(root, 1);
btrfs_throttle(root);
}
buf += write_bytes;
count -= write_bytes;
pos += write_bytes;
num_written += write_bytes;
cond_resched();
}
out:
mutex_unlock(&inode->i_mutex);
if (ret)
err = ret;
out_nolock:
kfree(pages);
if (pinned[0])
page_cache_release(pinned[0]);
if (pinned[1])
page_cache_release(pinned[1]);
*ppos = pos;
Btrfs: add extra flushing for renames and truncates Renames and truncates are both common ways to replace old data with new data. The filesystem can make an effort to make sure the new data is on disk before actually replacing the old data. This is especially important for rename, which many application use as though it were atomic for both the data and the metadata involved. The current btrfs code will happily replace a file that is fully on disk with one that was just created and still has pending IO. If we crash after transaction commit but before the IO is done, we'll end up replacing a good file with a zero length file. The solution used here is to create a list of inodes that need special ordering and force them to disk before the commit is done. This is similar to the ext3 style data=ordering, except it is only done on selected files. Btrfs is able to get away with this because it does not wait on commits very often, even for fsync (which use a sub-commit). For renames, we order the file when it wasn't already on disk and when it is replacing an existing file. Larger files are sent to filemap_flush right away (before the transaction handle is opened). For truncates, we order if the file goes from non-zero size down to zero size. This is a little different, because at the time of the truncate the file has no dirty bytes to order. But, we flag the inode so that it is added to the ordered list on close (via release method). We also immediately add it to the ordered list of the current transaction so that we can try to flush down any writes the application sneaks in before commit. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-31 17:27:11 +00:00
/*
* we want to make sure fsync finds this change
* but we haven't joined a transaction running right now.
*
* Later on, someone is sure to update the inode and get the
* real transid recorded.
*
* We set last_trans now to the fs_info generation + 1,
* this will either be one more than the running transaction
* or the generation used for the next transaction if there isn't
* one running right now.
*/
BTRFS_I(inode)->last_trans = root->fs_info->generation + 1;
if (num_written > 0 && will_write) {
struct btrfs_trans_handle *trans;
err = btrfs_wait_ordered_range(inode, start_pos, num_written);
if (err)
num_written = err;
if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
trans = btrfs_start_transaction(root, 1);
ret = btrfs_log_dentry_safe(trans, root,
file->f_dentry);
if (ret == 0) {
Btrfs: tree logging unlink/rename fixes The tree logging code allows individual files or directories to be logged without including operations on other files and directories in the FS. It tries to commit the minimal set of changes to disk in order to fsync the single file or directory that was sent to fsync or O_SYNC. The tree logging code was allowing files and directories to be unlinked if they were part of a rename operation where only one directory in the rename was in the fsync log. This patch adds a few new rules to the tree logging. 1) on rename or unlink, if the inode being unlinked isn't in the fsync log, we must force a full commit before doing an fsync of the directory where the unlink was done. The commit isn't done during the unlink, but it is forced the next time we try to log the parent directory. Solution: record transid of last unlink/rename per directory when the directory wasn't already logged. For renames this is only done when renaming to a different directory. mkdir foo/some_dir normal commit rename foo/some_dir foo2/some_dir mkdir foo/some_dir fsync foo/some_dir/some_file The fsync above will unlink the original some_dir without recording it in its new location (foo2). After a crash, some_dir will be gone unless the fsync of some_file forces a full commit 2) we must log any new names for any file or dir that is in the fsync log. This way we make sure not to lose files that are unlinked during the same transaction. 2a) we must log any new names for any file or dir during rename when the directory they are being removed from was logged. 2a is actually the more important variant. Without the extra logging a crash might unlink the old name without recreating the new one 3) after a crash, we must go through any directories with a link count of zero and redo the rm -rf mkdir f1/foo normal commit rm -rf f1/foo fsync(f1) The directory f1 was fully removed from the FS, but fsync was never called on f1, only its parent dir. After a crash the rm -rf must be replayed. This must be able to recurse down the entire directory tree. The inode link count fixup code takes care of the ugly details. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 14:24:20 +00:00
ret = btrfs_sync_log(trans, root);
if (ret == 0)
btrfs_end_transaction(trans, root);
else
btrfs_commit_transaction(trans, root);
} else {
btrfs_commit_transaction(trans, root);
}
}
if (file->f_flags & O_DIRECT) {
invalidate_mapping_pages(inode->i_mapping,
start_pos >> PAGE_CACHE_SHIFT,
(start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
}
}
current->backing_dev_info = NULL;
return num_written ? num_written : err;
}
int btrfs_release_file(struct inode *inode, struct file *filp)
{
Btrfs: add extra flushing for renames and truncates Renames and truncates are both common ways to replace old data with new data. The filesystem can make an effort to make sure the new data is on disk before actually replacing the old data. This is especially important for rename, which many application use as though it were atomic for both the data and the metadata involved. The current btrfs code will happily replace a file that is fully on disk with one that was just created and still has pending IO. If we crash after transaction commit but before the IO is done, we'll end up replacing a good file with a zero length file. The solution used here is to create a list of inodes that need special ordering and force them to disk before the commit is done. This is similar to the ext3 style data=ordering, except it is only done on selected files. Btrfs is able to get away with this because it does not wait on commits very often, even for fsync (which use a sub-commit). For renames, we order the file when it wasn't already on disk and when it is replacing an existing file. Larger files are sent to filemap_flush right away (before the transaction handle is opened). For truncates, we order if the file goes from non-zero size down to zero size. This is a little different, because at the time of the truncate the file has no dirty bytes to order. But, we flag the inode so that it is added to the ordered list on close (via release method). We also immediately add it to the ordered list of the current transaction so that we can try to flush down any writes the application sneaks in before commit. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-31 17:27:11 +00:00
/*
* ordered_data_close is set by settattr when we are about to truncate
* a file from a non-zero size to a zero size. This tries to
* flush down new bytes that may have been written if the
* application were using truncate to replace a file in place.
*/
if (BTRFS_I(inode)->ordered_data_close) {
BTRFS_I(inode)->ordered_data_close = 0;
btrfs_add_ordered_operation(NULL, BTRFS_I(inode)->root, inode);
if (inode->i_size > BTRFS_ORDERED_OPERATIONS_FLUSH_LIMIT)
filemap_flush(inode->i_mapping);
}
if (filp->private_data)
btrfs_ioctl_trans_end(filp);
return 0;
}
/*
* fsync call for both files and directories. This logs the inode into
* the tree log instead of forcing full commits whenever possible.
*
* It needs to call filemap_fdatawait so that all ordered extent updates are
* in the metadata btree are up to date for copying to the log.
*
* It drops the inode mutex before doing the tree log commit. This is an
* important optimization for directories because holding the mutex prevents
* new operations on the dir while we write to disk.
*/
int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
{
struct inode *inode = dentry->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
int ret = 0;
struct btrfs_trans_handle *trans;
/*
* check the transaction that last modified this inode
* and see if its already been committed
*/
if (!BTRFS_I(inode)->last_trans)
goto out;
mutex_lock(&root->fs_info->trans_mutex);
if (BTRFS_I(inode)->last_trans <=
root->fs_info->last_trans_committed) {
BTRFS_I(inode)->last_trans = 0;
mutex_unlock(&root->fs_info->trans_mutex);
goto out;
}
mutex_unlock(&root->fs_info->trans_mutex);
root->log_batch++;
filemap_fdatawrite(inode->i_mapping);
btrfs_wait_ordered_range(inode, 0, (u64)-1);
root->log_batch++;
/*
* ok we haven't committed the transaction yet, lets do a commit
*/
if (file && file->private_data)
btrfs_ioctl_trans_end(file);
trans = btrfs_start_transaction(root, 1);
if (!trans) {
ret = -ENOMEM;
goto out;
}
ret = btrfs_log_dentry_safe(trans, root, dentry);
if (ret < 0)
goto out;
/* we've logged all the items and now have a consistent
* version of the file in the log. It is possible that
* someone will come in and modify the file, but that's
* fine because the log is consistent on disk, and we
* have references to all of the file's extents
*
* It is possible that someone will come in and log the
* file again, but that will end up using the synchronization
* inside btrfs_sync_log to keep things safe.
*/
mutex_unlock(&dentry->d_inode->i_mutex);
if (ret > 0) {
ret = btrfs_commit_transaction(trans, root);
} else {
Btrfs: tree logging unlink/rename fixes The tree logging code allows individual files or directories to be logged without including operations on other files and directories in the FS. It tries to commit the minimal set of changes to disk in order to fsync the single file or directory that was sent to fsync or O_SYNC. The tree logging code was allowing files and directories to be unlinked if they were part of a rename operation where only one directory in the rename was in the fsync log. This patch adds a few new rules to the tree logging. 1) on rename or unlink, if the inode being unlinked isn't in the fsync log, we must force a full commit before doing an fsync of the directory where the unlink was done. The commit isn't done during the unlink, but it is forced the next time we try to log the parent directory. Solution: record transid of last unlink/rename per directory when the directory wasn't already logged. For renames this is only done when renaming to a different directory. mkdir foo/some_dir normal commit rename foo/some_dir foo2/some_dir mkdir foo/some_dir fsync foo/some_dir/some_file The fsync above will unlink the original some_dir without recording it in its new location (foo2). After a crash, some_dir will be gone unless the fsync of some_file forces a full commit 2) we must log any new names for any file or dir that is in the fsync log. This way we make sure not to lose files that are unlinked during the same transaction. 2a) we must log any new names for any file or dir during rename when the directory they are being removed from was logged. 2a is actually the more important variant. Without the extra logging a crash might unlink the old name without recreating the new one 3) after a crash, we must go through any directories with a link count of zero and redo the rm -rf mkdir f1/foo normal commit rm -rf f1/foo fsync(f1) The directory f1 was fully removed from the FS, but fsync was never called on f1, only its parent dir. After a crash the rm -rf must be replayed. This must be able to recurse down the entire directory tree. The inode link count fixup code takes care of the ugly details. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 14:24:20 +00:00
ret = btrfs_sync_log(trans, root);
if (ret == 0)
ret = btrfs_end_transaction(trans, root);
else
ret = btrfs_commit_transaction(trans, root);
}
mutex_lock(&dentry->d_inode->i_mutex);
out:
return ret > 0 ? EIO : ret;
}
static struct vm_operations_struct btrfs_file_vm_ops = {
.fault = filemap_fault,
.page_mkwrite = btrfs_page_mkwrite,
};
static int btrfs_file_mmap(struct file *filp, struct vm_area_struct *vma)
{
vma->vm_ops = &btrfs_file_vm_ops;
file_accessed(filp);
return 0;
}
struct file_operations btrfs_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.aio_read = generic_file_aio_read,
.splice_read = generic_file_splice_read,
.write = btrfs_file_write,
.mmap = btrfs_file_mmap,
.open = generic_file_open,
.release = btrfs_release_file,
.fsync = btrfs_sync_file,
.unlocked_ioctl = btrfs_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = btrfs_ioctl,
#endif
};