These are all the cases where a variable is set, but not
read which are really bugs.
- Couple of incorrect error handling fixed.
- One incorrect use of a allocation policy
- Some other things
Still needs more review.
Found by gcc 4.6's new warnings.
[akpm@linux-foundation.org: fix build. Might have been bitrot]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This is a simple bit, just dump the free space cache out to our preallocated
inode when we're writing out dirty block groups. There are a bunch of changes
in inode.c in order to account for special cases. Mostly when we're doing the
writeout we're holding trans_mutex, so we need to use the nolock transacation
functions. Also we can't do asynchronous completions since the async thread
could be blocked on already completed IO waiting for the transaction lock. This
has been tested with xfstests and btrfs filesystem balance, as well as my ENOSPC
tests. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
In order to save free space cache, we need an inode to hold the data, and we
need a special item to point at the right inode for the right block group. So
first, create a special item that will point to the right inode, and the number
of extent entries we will have and the number of bitmaps we will have. We
truncate and pre-allocate space everytime to make sure it's uptodate.
This feature will be turned on as soon as you mount with -o space_cache, however
it is safe to boot into old kernels, they will just generate the cache the old
fashion way. When you boot back into a newer kernel we will notice that we
modified and not the cache and automatically discard the cache.
Signed-off-by: Josef Bacik <josef@redhat.com>
Currently we try and flush delalloc, but we only do that in a sort of weak way,
which works fine in most cases but if we're under heavy pressure we need to be
able to wait for flushing to happen. Also instead of checking the bytes
reserved in the block_rsv, check the space info since it is more accurate. The
sync option will be used in a future patch.
Signed-off-by: Josef Bacik <josef@redhat.com>
* 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block: (149 commits)
block: make sure that REQ_* types are seen even with CONFIG_BLOCK=n
xen-blkfront: fix missing out label
blkdev: fix blkdev_issue_zeroout return value
block: update request stacking methods to support discards
block: fix missing export of blk_types.h
writeback: fix bad _bh spinlock nesting
drbd: revert "delay probes", feature is being re-implemented differently
drbd: Initialize all members of sync_conf to their defaults [Bugz 315]
drbd: Disable delay probes for the upcomming release
writeback: cleanup bdi_register
writeback: add new tracepoints
writeback: remove unnecessary init_timer call
writeback: optimize periodic bdi thread wakeups
writeback: prevent unnecessary bdi threads wakeups
writeback: move bdi threads exiting logic to the forker thread
writeback: restructure bdi forker loop a little
writeback: move last_active to bdi
writeback: do not remove bdi from bdi_list
writeback: simplify bdi code a little
writeback: do not lose wake-ups in bdi threads
...
Fixed up pretty trivial conflicts in drivers/block/virtio_blk.c and
drivers/scsi/scsi_error.c as per Jens.
BTRFS does not define a '->write_super()' method, so it should
not mark its superblock as dirty. This looks like some left-over.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
NB: do we want btrfs_wait_ordered_range() on eviction of
inodes with positive i_nlink on subvolume with zero root_refs?
If not, btrfs_evict_inode() can be simplified by unconditionally
bailing out in case of i_nlink > 0 in the very beginning...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
add I_CLEAR instead of replacing I_FREEING with it. I_CLEAR is
equivalent to I_FREEING for almost all code looking at either;
it's there to keep track of having called clear_inode() exactly
once per inode lifetime, at some point after having set I_FREEING.
I_CLEAR and I_FREEING never get set at the same time with the
current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR
instead of I_CLEAR without loss of information. As the result of
such change, checks become simpler and the amount of code that needs
to know about I_CLEAR shrinks a lot.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Replace inode_setattr with opencoded variants of it in all callers. This
moves the remaining call to vmtruncate into the filesystem methods where it
can be replaced with the proper truncate sequence.
In a few cases it was obvious that we would never end up calling vmtruncate
so it was left out in the opencoded variant:
spufs: explicitly checks for ATTR_SIZE earlier
btrfs,hugetlbfs,logfs,dlmfs: explicitly clears ATTR_SIZE earlier
ufs: contains an opencoded simple_seattr + truncate that sets the filesize just above
In addition to that ncpfs called inode_setattr with handcrafted iattrs,
which allowed to trim down the opencoded variant.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver. There were two flags in the bio that were
missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've
renamed two request flags that had a superflous RW in them.
Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: The file argument for fsync() is never null
Btrfs: handle ERR_PTR from posix_acl_from_xattr()
Btrfs: avoid BUG when dropping root and reference in same transaction
Btrfs: prohibit a operation of changing acl's mask when noacl mount option used
Btrfs: should add a permission check for setfacl
Btrfs: btrfs_lookup_dir_item() can return ERR_PTR
Btrfs: btrfs_read_fs_root_no_name() returns ERR_PTRs
Btrfs: unwind after btrfs_start_transaction() errors
Btrfs: btrfs_iget() returns ERR_PTR
Btrfs: handle kzalloc() failure in open_ctree()
Btrfs: handle error returns from btrfs_lookup_dir_item()
Btrfs: Fix BUG_ON for fs converted from extN
Btrfs: Fix null dereference in relocation.c
Btrfs: fix remap_file_pages error
Btrfs: uninitialized data is check_path_shared()
Btrfs: fix fallocate regression
Btrfs: fix loop device on top of btrfs
refs can be used with uninitialized data if btrfs_lookup_extent_info()
fails on the first pass through the loop. In the original code if that
happens then check_path_shared() probably returns 1, this patch
changes it to return 1 for safety.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Seems that when btrfs_fallocate was converted to use the new ENOSPC stuff we
dropped passing the mode to the function that actually does the preallocation.
This breaks anybody who wants to use FALLOC_FL_KEEP_SIZE. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (27 commits)
Btrfs: add more error checking to btrfs_dirty_inode
Btrfs: allow unaligned DIO
Btrfs: drop verbose enospc printk
Btrfs: Fix block generation verification race
Btrfs: fix preallocation and nodatacow checks in O_DIRECT
Btrfs: avoid ENOSPC errors in btrfs_dirty_inode
Btrfs: move O_DIRECT space reservation to btrfs_direct_IO
Btrfs: rework O_DIRECT enospc handling
Btrfs: use async helpers for DIO write checksumming
Btrfs: don't walk around with task->state != TASK_RUNNING
Btrfs: do aio_write instead of write
Btrfs: add basic DIO read/write support
direct-io: do not merge logically non-contiguous requests
direct-io: add a hook for the fs to provide its own submit_bio function
fs: allow short direct-io reads to be completed via buffered IO
Btrfs: Metadata ENOSPC handling for balance
Btrfs: Pre-allocate space for data relocation
Btrfs: Metadata ENOSPC handling for tree log
Btrfs: Metadata reservation for orphan inodes
Btrfs: Introduce global metadata reservation
...
The ENOSPC code will now return ENOSPC to btrfs_start_transaction.
btrfs_dirty_inode needs to check for this and error out appropriately.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
In order to support DIO that isn't aligned to the filesystem blocksize,
we fall back to buffered for any unaligned DIOs.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The O_DIRECT code wasn't checking for multiple references
on preallocated or nodatacow extents. This means it
wasn't honoring snapshots properly.
The fix here is to add an explicit check for multiple references
This also fixes the math for selecting the correct disk block,
making sure not to go past the end of the extent.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs_dirty_inode tries to sneak in without much waiting or
space reservation, mostly for performance reasons. This
usually works well but can cause problems when there are
many many writers.
When btrfs_update_inode fails with ENOSPC, we fallback
to a slower btrfs_start_transaction call that will reserve
some space.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This moves the delalloc space reservation done for O_DIRECT
into btrfs_direct_IO. This way we don't leak reserved space
if the generic O_DIRECT write code errors out before it
calls into btrfs_direct_IO.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This changes O_DIRECT write code to mark extents as delalloc
while it is processing them. Yan Zheng has reworked the
enospc accounting based on tracking delalloc extents and
this makes it much easier to track enospc in the O_DIRECT code.
There are a few space cases with the O_DIRECT code though,
it only sets the EXTENT_DELALLOC bits, instead of doing
EXTENT_DELALLOC | EXTENT_DIRTY | EXTENT_UPTODATE, because
we don't want to mess with clearing the dirty and uptodate
bits when things go wrong. This is important because there
are no pages in the page cache, so any extent state structs
that we put in the tree won't get freed by releasepage. We have
to clear them ourselves as the DIO ends.
With this commit, we reserve space at in btrfs_file_aio_write,
and then as each btrfs_direct_IO call progresses it sets
EXTENT_DELALLOC on the range.
btrfs_get_blocks_direct is responsible for clearing the delalloc
at the same time it drops the extent lock.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The async helper threads offload crc work onto all the
CPUs, and make streaming writes much faster. This
changes the O_DIRECT write code to use them. The only
small complication was that we need to pass in the
logical offset in the file for each bio, because we can't
find it in the bio's pages.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This provides basic DIO support for reading and writing. It does not do the
work to recover from mismatching checksums, that will come later. A few design
changes have been made from Jim's code (sorry Jim!)
1) Use the generic direct-io code. Jim originally re-wrote all the generic DIO
code in order to account for all of BTRFS's oddities, but thanks to that work it
seems like the best bet is to just ignore compression and such and just opt to
fallback on buffered IO.
2) Fallback on buffered IO for compressed or inline extents. Jim's code did
it's own buffering to make dio with compressed extents work. Now we just
fallback onto normal buffered IO.
3) Use ordered extents for the writes so that all of the
lock_extent()
lookup_ordered()
type checks continue to work.
4) Do the lock_extent() lookup_ordered() loop in readpage so we don't race with
DIO writes.
I've tested this with fsx and everything works great. This patch depends on my
dio and filemap.c patches to work. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Pre-allocate space for data relocation. This can detect ENOPSC
condition caused by fragmentation of free space.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Reserve metadata space for extent tree, checksum tree and root tree
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Introduce metadata reservation context for delayed allocation
and update various related functions.
This patch also introduces EXTENT_FIRST_DELALLOC control bit for
set/clear_extent_bit. It tells set/clear_bit_hook whether they
are processing the first extent_state with EXTENT_DELALLOC bit
set. This change is important if set/clear_extent_bit involves
multiple extent_state.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Besides simplify the code, this change makes sure all metadata
reservation for normal metadata operations are released after
committing transaction.
Changes since V1:
Add code that check if unlink and rmdir will free space.
Add ENOSPC handling for clone ioctl.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
All code in init_btrfs_i can be moved into btrfs_alloc_inode()
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Shrink delayed allocation space in a synchronized manner is more
controllable than flushing all delay allocated space in an async
thread.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: add check for changed leaves in setup_leaf_for_split
Btrfs: create snapshot references in same commit as snapshot
Btrfs: fix small race with delalloc flushing waitqueue's
Btrfs: use add_to_page_cache_lru, use __page_cache_alloc
Btrfs: fix chunk allocate size calculation
Btrfs: kill max_extent mount option
Btrfs: fail to mount if we have problems reading the block groups
Btrfs: check btrfs_get_extent return for IS_ERR()
Btrfs: handle kmalloc() failure in inode lookup ioctl
Btrfs: dereferencing freed memory
Btrfs: Simplify num_stripes's calculation logical for __btrfs_alloc_chunk()
Btrfs: Add error handle for btrfs_search_slot() in btrfs_read_chunk_tree()
Btrfs: Remove unnecessary finish_wait() in wait_current_trans()
Btrfs: add NULL check for do_walk_down()
Btrfs: remove duplicate include in ioctl.c
Fix trivial conflict in fs/btrfs/compression.c due to slab.h include
cleanups.
As Yan pointed out, theres not much reason for all this complicated math to
account for file extents being split up into max_extent chunks, since they are
likely to all end up in the same leaf anyway. Since there isn't much reason to
use max_extent, just remove the option altogether so we have one less thing we
need to test.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (30 commits)
Btrfs: fix the inode ref searches done by btrfs_search_path_in_tree
Btrfs: allow treeid==0 in the inode lookup ioctl
Btrfs: return keys for large items to the search ioctl
Btrfs: fix key checks and advance in the search ioctl
Btrfs: buffer results in the space_info ioctl
Btrfs: use __u64 types in ioctl.h
Btrfs: fix search_ioctl key advance
Btrfs: fix gfp flags masking in the compression code
Btrfs: don't look at bio flags after submit_bio
btrfs: using btrfs_stack_device_id() get devid
btrfs: use memparse
Btrfs: add a "df" ioctl for btrfs
Btrfs: cache the extent state everywhere we possibly can V2
Btrfs: cache ordered extent when completing io
Btrfs: cache extent state in find_delalloc_range
Btrfs: change the ordered tree to use a spinlock instead of a mutex
Btrfs: finish read pages in the order they are submitted
btrfs: fix btrfs_mkdir goto for no free objectids
Btrfs: flush data on snapshot creation
Btrfs: make df be a little bit more understandable
...
This patch just goes through and fixes everybody that does
lock_extent()
blah
unlock_extent()
to use
lock_extent_bits()
blah
unlock_extent_cached()
and pass around a extent_state so we only have to do the searches once per
function. This gives me about a 3 mb/s boots on my random write test. I have
not converted some things, like the relocation and ioctl's, since they aren't
heavily used and the relocation stuff is in the middle of being re-written. I
also changed the clear_extent_bit() to only unset the cached state if we are
clearing EXTENT_LOCKED and related stuff, so we can do things like this
lock_extent_bits()
clear delalloc bits
unlock_extent_cached()
without losing our cached state. I tested this thoroughly and turned on
LEAK_DEBUG to make sure we weren't leaking extent states, everything worked out
fine.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When finishing io we run btrfs_dec_test_ordered_pending, and then immediately
run btrfs_lookup_ordered_extent, but btrfs_dec_test_ordered_pending does that
already, so we're searching twice when we don't have to. This patch lets us
pass a btrfs_ordered_extent in to btrfs_dec_test_ordered_pending so if we do
complete io on that ordered extent we can just use the one we found then instead
of having to do another btrfs_lookup_ordered_extent. This made my fio job with
the other patch go from 24 mb/s to 29 mb/s.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs_mkdir() must jump to the place of ending transaction after
btrfs_find_free_objectid() failed. Or this transaction can't end.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The btrfs defrag ioctl was limited to doing the entire file. This
commit adds a new interface that can defrag a specific range inside
the file.
It can also force compression on the file, allowing you to selectively
compress individual files after they were created, even when mount -o
compress isn't turned on.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This work is in preperation for being able to set a different root as the
default mounting root.
There is currently a problem with how we mount subvolumes. We cannot currently
mount a subvolume of a subvolume, you can only mount subvolumes/snapshots of the
default subvolume. So say you take a snapshot of the default subvolume and call
it snap1, and then take a snapshot of snap1 and call it snap2, so now you have
/
/snap1
/snap1/snap2
as your available volumes. Currently you can only mount / and /snap1,
you cannot mount /snap1/snap2. To fix this problem instead of passing
subvolid=<name> you must pass in subvolid=<treeid>, where <treeid> is
the tree id that gets spit out via the subvolume listing you get from
the subvolume listing patches (btrfs filesystem list). This allows us
to mount /, /snap1 and /snap1/snap2 as the root volume.
In addition to the above, we also now read the default dir item in the
tree root to get the root key that it points to. For now this just
points at what has always been the default subvolme, but later on I plan
to change it to point at whatever root you want to be the new default
root, so you can just set the default mount and not have to mount with
-o subvolid=<treeid>. I tested this out with the above scenario and it
worked perfectly. Thanks,
mount -o subvol operates inside the selected subvolid. For example:
mount -o subvol=snap1,subvolid=256 /dev/xxx /mnt
/mnt will have the snap1 directory for the subvolume with id
256.
mount -o subvol=snap /dev/xxx /mnt
/mnt will be the snap directory of whatever the default subvolume
is.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This gives the filesystem more information about the writeback that
is happening. Trond requested this for the NFS unstable write handling,
and other filesystems might benefit from this too by beeing able to
distinguish between the different callers in more detail.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This version of the i_size fix for fallocate makes sure we only update
the i_size when the current fallocate is really operating outside of
i_size.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When running the following fio job
[torrent]
filename=torrent-test
rw=randwrite
size=4g
filesize=4g
bs=4k
ioengine=sync
you would see long stalls where no work was being done. That is because we were
doing all this extra work to read in the file extent outside of the transaction,
however in the random io case this ends up hurting us because the file extents
are not there to begin with. So axe this logic, since we end up reading in the
file extent when we go to update it anyway. This took the fio job from 11 mb/s
with several ~10 second stalls to 24 mb/s to a couple of 1-2 second stalls.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This patch revert's commit
6c090a11e1
Since it introduces this problem where we can run orphan cleanup on a
volume that can have orphan entries re-added. Instead of my original
fix, Yan Zheng pointed out that we can just revert my original fix and
then run the orphan cleanup in open_ctree after we look up the fs_root.
I have tested this with all the tests that gave me problems and this
patch fixes both problems. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
commit f2bc9dd07e3424c4ec5f3949961fe053d47bc825
Author: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Wed Jan 20 12:57:53 2010 +0530
Btrfs: Use correct values when updating inode i_size on fallocate
Even though we allocate more, we should be updating inode i_size
as per the arguments passed
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The default btrfs mount -o compress mode will quickly back off
compressing a file if it notices that compression does not reduce the
size of the data being written. This can save considerable CPU because
all future writes to the file go through uncompressed.
But some files are both very large and have mixed data stored in
them. In that case, we want to add the ability to always try
compressing data before writing it.
This commit adds mount -o compress-force. A later commit will add
a new inode flag that does the same thing.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Currently orphan cleanup only ever gets triggered if we cross subvolumes during
a lookup, which means that if we just mount a plain jane fs that has orphans in
it, they will never get cleaned up. This results in panic's like these
http://www.kerneloops.org/oops.php?number=1109085
where adding an orphan entry results in -EEXIST being returned and we panic. In
order to fix this, we check to see on lookup if our root has had the orphan
cleanup done, and if not go ahead and do it. This is easily reproduceable by
running this testcase
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
int main(int argc, char **argv)
{
char data[4096];
char newdata[4096];
int fd1, fd2;
memset(data, 'a', 4096);
memset(newdata, 'b', 4096);
while (1) {
int i;
fd1 = creat("file1", 0666);
if (fd1 < 0)
break;
for (i = 0; i < 512; i++)
write(fd1, data, 4096);
fsync(fd1);
close(fd1);
fd2 = creat("file2", 0666);
if (fd2 < 0)
break;
ftruncate(fd2, 4096 * 512);
for (i = 0; i < 512; i++)
write(fd2, newdata, 4096);
close(fd2);
i = rename("file2", "file1");
unlink("file1");
}
return 0;
}
and then pulling the power on the box, and then trying to run that test again
when the box comes back up. I've tested this locally and it fixes the problem.
Thanks to Tomas Carnecky for helping me track this down initially.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
parent 49313cdac7b34c9f7ecbb1780cfc648b1c082cd7 (v2.6.32-1-g49313cd)
commit ff48c08e1c05c67e8348ab6f8a24de8034e0e34d
Author: Jan Engelhardt <jengelh@medozas.de>
Date: Wed Dec 9 22:57:36 2009 +0100
Btrfs: fix missing last-entry in readdir(3)
When one does a 32-bit readdir(3), the last entry of a directory is
missing. This is however not due to passing a large value to filldir,
but it seems to have to do with glibc doing telldir or something
quirky. In any case, this patch fixes it in practice.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The recent patch to make fallocate enospc friendly would send
down a NULL trans handle to the allocator. This moves the
transaction start to properly fix things.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
I rebased Christian Parpart's patch to deny hard link across
subvolumes. Original patch modifies also btrfs_rename, but
I excluded it because we can move across subvolumes now and
it make no problem.
-----------------
Hard link across subvolumes should not allowed in Btrfs.
btrfs_link checks root of 'to' directory is same as root
of 'from' file. If not same, btrfs_link returns -EPERM.
Signed-off-by: TARUISI Hiroaki <taruishi.hiroak@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
iput() can trigger new transactions if we are dropping the
final reference, so calling it in btrfs_commit_transaction
may end up deadlock. This patch adds delayed iput to avoid
the issue.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Pass transaction handle down to security and ACL initialization
functions, so we can avoid starting nested transactions
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
truncating and deleting regular files are unbound operations,
so it's not good to do them in a single transaction. This
patch makes btrfs_truncate and btrfs_delete_inode start a
new transaction after all items in a tree leaf are deleted.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
fallocate(2) may allocate large number of file extents, so it's not
good to do it in a single transaction. This patch make fallocate(2)
start a new transaction for each file extents it allocates.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We do log replay in a single transaction, so it's not good to do unbound
operations. This patch cleans up orphan inodes cleanup after replaying
the log. It also avoids doing other unbound operations such as truncating
a file during replaying log. These unbound operations are postponed to
the orphan inode cleanup stage.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
There are some cases file extents are inserted without involving
ordered struct. In these cases, we update disk_i_size directly,
without checking pending ordered extent and DELALLOC bit. This
patch extends btrfs_ordered_update_i_size() to handle these cases.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Rewrite btrfs_drop_extents by using btrfs_duplicate_item, so we can
avoid calling lock_extent within transaction.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: fix panic when trying to destroy a newly allocated
Btrfs: allow more metadata chunk preallocation
Btrfs: fallback on uncompressed io if compressed io fails
Btrfs: find ideal block group for caching
Btrfs: avoid null deref in unpin_extent_cache()
Btrfs: skip btrfs_release_path in btrfs_update_root and btrfs_del_root
Btrfs: fix some metadata enospc issues
Btrfs: fix how we set max_size for free space clusters
Btrfs: cleanup transaction starting and fix journal_info usage
Btrfs: fix data allocation hint start
There is a problem where iget5_locked will look for an inode, not find it, and
then subsequently try to allocate it. Another CPU will have raced in and
allocated the inode instead, so when iget5_locked gets the inode spin lock again
and does a search, it finds the new inode. So it goes ahead and calls
destroy_inode on the inode it just allocated. The problem is we don't set
BTRFS_I(inode)->root until the new inode is completely initialized. This patch
makes us set root to NULL when alloc'ing a new inode, so when we get to
btrfs_destroy_inode and we see that root is NULL we can just free up the memory
and continue on. This fixes the panic
http://www.kerneloops.org/submitresult.php?number=812690
Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Currently compressed IO does not deal with not having its entire extent able to
be allocated. So if we have enough free space to allocate for the extent, but
its not contiguous, it will fail spectacularly. This patch fixes this by
falling back on uncompressed IO which lets us spread the delalloc extent across
multiple extents. I tested this by making us randomly think the reservation had
failed to make it fallback on the uncompressed io way and it seemed to work
fine. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We weren't reserving metadata space for rename, rmdir and unlink, which could
cause problems.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Sometimes our start allocation hint when we cow a file can be either
EXTENT_HOLE or some other such place holder, which is not optimal. So if we
find that our em->block_start is one of these special values, check to see
where the first block of the inode is stored, and use that as a hint. If that
block is also a special value, just fallback on a hint of 0 and let the
allocator figure out a good place to put the data.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: always pin metadata in discard mode
Btrfs: enable discard support
Btrfs: add -o discard option
Btrfs: properly wait log writers during log sync
Btrfs: fix possible ENOSPC problems with truncate
Btrfs: fix btrfs acl #ifdef checks
Btrfs: streamline tree-log btree block writeout
Btrfs: avoid tree log commit when there are no changes
Btrfs: only write one super copy during fsync
There's a problem where we don't do any space reservation for truncates, which
can cause you to OOPs because you will be allowed to go off in the weeds a bit
since we don't account for the delalloc bytes that are created as a result of
the truncate.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
rpm has a habit of running fdatasync when the file hasn't
changed. We already detect if a file hasn't been changed
in the current transaction but it might have been sent to
the tree-log in this transaction and not changed since
the last call to fsync.
In this case, we want to avoid a tree log sync, which includes
a number of synchronous writes and barriers. This commit
extends the existing tracking of the last transaction to change
a file to also track the last sub-transaction.
The end result is that rpm -ivh and -Uvh are roughly twice as fast,
and on par with ext3.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: fix file clone ioctl for bookend extents
Btrfs: fix uninit compiler warning in cow_file_range_nocow
Btrfs: constify dentry_operations
Btrfs: optimize back reference update during btrfs_drop_snapshot
Btrfs: remove negative dentry when deleting subvolumne
Btrfs: optimize fsync for the single writer case
Btrfs: async delalloc flushing under space pressure
Btrfs: release delalloc reservations on extent item insertion
Btrfs: delay clearing EXTENT_DELALLOC for compressed extents
Btrfs: cleanup extent_clear_unlock_delalloc flags
Btrfs: fix possible softlockup in the allocator
Btrfs: fix deadlock on async thread startup
The extent_type variable was exposed uninit via a goto. It should be
impossible to trigger because it is protected by a check on another
variable, but this makes sure.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The use of btrfs_dentry_delete is removing dentries from the
dcache when deleting subvolumne. btrfs_dentry_delete ignores
negative dentries. This is incorrect since if we don't remove
the negative dentry, its parent dentry can't be removed.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This patch fixes an issue with the delalloc metadata space reservation
code. The problem is we used to free the reservation as soon as we
allocated the delalloc region. The problem with this is if we are not
inserting an inline extent, we don't actually insert the extent item until
after the ordered extent is written out. This patch does 3 things,
1) It moves the reservation clearing stuff into the ordered code, so when
we remove the ordered extent we remove the reservation.
2) It adds a EXTENT_DO_ACCOUNTING flag that gets passed when we clear
delalloc bits in the cases where we want to clear the metadata reservation
when we clear the delalloc extent, in the case that we do an inline extent
or we invalidate the page.
3) It adds another waitqueue to the space info so that when we start a fs
wide delalloc flush, anybody else who also hits that area will simply wait
for the flush to finish and then try to make their allocation.
This has been tested thoroughly to make sure we did not regress on
performance.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When compression is on, the cow_file_range code is farmed off to
worker threads. This allows us to do significant CPU work in parallel
on SMP machines.
But it is a delicate balance around when we clear flags and how. In
the past we cleared the delalloc flag immediately, which was safe
because the pages stayed locked.
But this is causing problems with the newest ENOSPC code, and with the
recent extent state cleanups we can now clear the delalloc bit at the
same time the uncompressed code does.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
extent_clear_unlock_delalloc has a growing set of ugly parameters
that is very difficult to read and maintain.
This switches to a flag field and well named flag defines.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: fix data space leak fix
Btrfs: remove duplicates of filemap_ helpers
Btrfs: take i_mutex before generic_write_checks
Btrfs: fix arguments to btrfs_wait_on_page_writeback_range
Btrfs: fix deadlock with free space handling and user transactions
Btrfs: fix error cases for ioctl transactions
Btrfs: Use CONFIG_BTRFS_POSIX_ACL to enable ACL code
Btrfs: introduce missing kfree
Btrfs: Fix setting umask when POSIX ACLs are not enabled
Btrfs: proper -ENOSPC handling
There is a problem where page_mkwrite can be called on a dirtied page that
already has a delalloc range associated with it. The fix is to clear any
delalloc bits for the range we are dirtying so the space accounting gets
handled properly. This is the same thing we do in the normal write case, so we
are consistent across the board. With this patch we no longer leak reserved
space.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
At the start of a transaction we do a btrfs_reserve_metadata_space() and
specify how many items we plan on modifying. Then once we've done our
modifications and such, just call btrfs_unreserve_metadata_space() for
the same number of items we reserved.
For keeping track of metadata needed for data I've had to add an extent_io op
for when we merge extents. This lets us track space properly when we are doing
sequential writes, so we don't end up reserving way more metadata space than
what we need.
The only place where the metadata space accounting is not done is in the
relocation code. This is because Yan is going to be reworking that code in the
near future, so running btrfs-vol -b could still possibly result in a ENOSPC
related panic. This patch also turns off the metadata_ratio stuff in order to
allow users to more efficiently use their disk space.
This patch makes it so we track how much metadata we need for an inode's
delayed allocation extents by tracking how many extents are currently
waiting for allocation. It introduces two new callbacks for the
extent_io tree's, merge_extent_hook and split_extent_hook. These help
us keep track of when we merge delalloc extents together and split them
up. Reservations are handled prior to any actually dirty'ing occurs,
and then we unreserve after we dirty.
btrfs_unreserve_metadata_for_delalloc() will make the appropriate
unreservations as needed based on the number of reservations we
currently have and the number of extents we currently have. Doing the
reservation outside of doing any of the actual dirty'ing lets us do
things like filemap_flush() the inode to try and force delalloc to
happen, or as a last resort actually start allocation on all delalloc
inodes in the fs. This has survived dbench, fs_mark and an fsx torture
test.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (42 commits)
Btrfs: hash the btree inode during fill_super
Btrfs: relocate file extents in clusters
Btrfs: don't rename file into dummy directory
Btrfs: check size of inode backref before adding hardlink
Btrfs: fix releasepage to avoid unlocking extents we haven't locked
Btrfs: Fix test_range_bit for whole file extents
Btrfs: fix errors handling cached state in set/clear_extent_bit
Btrfs: fix early enospc during balancing
Btrfs: deal with NULL space info
Btrfs: account for space used by the super mirrors
Btrfs: fix extent entry threshold calculation
Btrfs: remove dead code
Btrfs: fix bitmap size tracking
Btrfs: don't keep retrying a block group if we fail to allocate a cluster
Btrfs: make balance code choose more wisely when relocating
Btrfs: fix arithmetic error in clone ioctl
Btrfs: add snapshot/subvolume destroy ioctl
Btrfs: change how subvolumes are organized
Btrfs: do not reuse objectid of deleted snapshot/subvol
Btrfs: speed up snapshot dropping
...
* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
HWPOISON: Enable error_remove_page on btrfs
HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
HWPOISON: Add madvise() based injector for hardware poisoned pages v4
HWPOISON: Enable error_remove_page for NFS
HWPOISON: Enable .remove_error_page for migration aware file systems
HWPOISON: The high level memory error handler in the VM v7
HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
HWPOISON: shmem: call set_page_dirty() with locked page
HWPOISON: Define a new error_remove_page address space op for async truncation
HWPOISON: Add invalidate_inode_page
HWPOISON: Refactor truncate to allow direct truncating of page v2
HWPOISON: check and isolate corrupted free pages v2
HWPOISON: Handle hardware poisoned pages in try_to_unmap
HWPOISON: Use bitmask/action code for try_to_unmap behaviour
HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
HWPOISON: Add poison check to page fault handling
HWPOISON: Add basic support for poisoned pages in fault handler v3
HWPOISON: Add new SIGBUS error codes for hardware poison signals
HWPOISON: Add support for poison swap entries v2
HWPOISON: Export some rmap vma locking to outside world
...
A recent change enforces only one access point to each subvolume. The first
directory entry (the one added when the subvolume/snapshot was created) is
treated as valid access point, all other subvolume links are linked to dummy
empty directories. The dummy directories are temporary inodes that only in
memory, so we can not rename file into them.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
For every hardlink in btrfs, there is a corresponding inode back
reference. All inode back references for hardlinks in a given
directory are stored in single b-tree item. The size of b-tree item
is limited by the size of b-tree leaf, so we can only create limited
number of hardlinks to a given file in a directory.
The original code lacks of the check, it oops if the number of
hardlinks goes over the limit. This patch fixes the issue by adding
check to btrfs_link and btrfs_rename.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This patch adds snapshot/subvolume destroy ioctl. A subvolume that isn't being
used and doesn't contains links to other subvolumes can be destroyed.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs allows subvolumes and snapshots anywhere in the directory tree.
If we snapshot a subvolume that contains a link to other subvolume
called subvolA, subvolA can be accessed through both the original
subvolume and the snapshot. This is similar to creating hard link to
directory, and has the very similar problems.
The aim of this patch is enforcing there is only one access point to
each subvolume. Only the first directory entry (the one added when
the subvolume/snapshot was created) is treated as valid access point.
The first directory entry is distinguished by checking root forward
reference. If the corresponding root forward reference is missing,
we know the entry is not the first one.
This patch also adds snapshot/subvolume rename support, the code
allows rename subvolume link across subvolumes.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The new back reference format does not allow reusing objectid of
deleted snapshot/subvol. So we use ++highest_objectid to allocate
objectid for new snapshot/subvol.
Now we use ++highest_objectid to allocate objectid for both new inode
and new snapshot/subvolume, so this patch removes 'find hole' code in
btrfs_find_free_objectid.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The allocator has some nice knobs for sending hints about where
to try and allocate new blocks, but when we're doing file allocations
we're not sending any hint at all.
This commit adds a simple extent map search to see if we can
quickly and easily find a hint for the allocator.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When btrfs_get_extent is reading inline file items for readpage,
it needs to copy the inline extent into the page. If the
inline extent doesn't cover all of the page, that means there
is a hole in the file, or that our file is smaller than one
page.
readpage does zeroing for the case where the file is smaller than one
page, but nobody is currently zeroing for the case where there is
a hole after the inline item.
This commit changes btrfs_get_extent to zero fill the page past
the end of the inline item.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This closes a whole where the page may be written before
the page_mkwrite caller has a chance to dirty it
(thanks to Nick Piggin)
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Data COW means that whenever we write to a file, we replace any old
extent pointers with new ones. There was a window where a readpage
might find the old extent pointers on disk and cache them in the
extent_map tree in ram in the middle of a given write replacing them.
Even though both the readpage and the write had their respective bytes
in the file locked, the extent readpage inserts may cover more bytes than
it had locked down.
This commit closes the race by keeping the new extent pinned in the extent
map tree until after the on-disk btree is properly setup with the new
extent pointers.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Btrfs writes go through delalloc to the data=ordered code. This
makes sure that all of the data is on disk before the metadata
that references it. The tracking means that we have to make sure
each page in an extent is fully written before we add that extent into
the on-disk btree.
This was done in the past by setting the EXTENT_ORDERED bit for the
range of an extent when it was added to the data=ordered code, and then
clearing the EXTENT_ORDERED bit in the extent state tree as each page
finished IO.
One of the reasons we had to do this was because sometimes pages are
magically dirtied without page_mkwrite being called. The EXTENT_ORDERED
bit is checked at writepage time, and if it isn't there, our page become
dirty without going through the proper path.
These bit operations make for a number of rbtree searches for each page,
and can cause considerable lock contention.
This commit switches from the EXTENT_ORDERED bit to use PagePrivate2.
As pages go into the ordered code, PagePrivate2 is set on each one.
This is a cheap operation because we already have all the pages locked
and ready to go.
As IO finishes, the PagePrivate2 bit is cleared and the ordered
accoutning is updated for each page.
At writepage time, if the PagePrivate2 bit is missing, we go into the
writepage fixup code to handle improperly dirtied pages.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This changes the btrfs code to find delalloc ranges in the extent state
tree to use the new state caching code from set/test bit. It reduces
one of the biggest causes of rbtree searches in the writeback path.
test_range_bit is also modified to take the cached state as a starting
point while searching.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Many of the btrfs extent state tree users follow the same pattern.
They lock an extent range in the tree, do some operation and then
unlock.
This translates to at least 2 rbtree searches, and maybe more if they
are doing operations on the extent state tree. A locked extent
in the tree isn't going to be merged or changed, and so we can
safely return the extent state structure as a cached handle.
This changes set_extent_bit to give back a cached handle, and also
changes both set_extent_bit and clear_extent_bit to use the cached
handle if it is available.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
There are two main users of the extent_map tree. The
first is regular file inodes, where it is evenly spread
between readers and writers.
The second is the chunk allocation tree, which maps blocks from
logical addresses to phyiscal ones, and it is 99.99% reads.
The mapping tree is a point of lock contention during heavy IO
workloads, so this commit switches things to a rw lock.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Node may not be inserted over existing node. This causes inode tree
corruption and I was seeing crashes in inode_tree_del which I can not
reproduce after this patch.
The other way to fix this would be to tie inode lifetime in the rbtree
with inode while not in freeing state. I had a look at this but it is
not so trivial at this point. At least this patch gets things working again.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Acked-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This takes care of the following entry from Dan's list:
fs/btrfs/inode.c +4788 btrfs_rename(36) warning: variable derefenced before check 'old_inode'
Reported-by: Dan Carpenter <error27@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Eugene Teo <eteo@redhat.com>
Cc: Julia Lawall <julia@diku.dk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (22 commits)
Btrfs: Fix async caching interaction with unmount
Btrfs: change how we unpin extents
Btrfs: Correct redundant test in add_inode_ref
Btrfs: find smallest available device extent during chunk allocation
Btrfs: clear all space_info->full after removing a block group
Btrfs: make flushoncommit mount option correctly wait on ordered_extents
Btrfs: Avoid delayed reference update looping
Btrfs: Fix ordering of key field checks in btrfs_previous_item
Btrfs: find_free_dev_extent doesn't handle holes at the start of the device
Btrfs: Remove code duplication in comp_keys
Btrfs: async block group caching
Btrfs: use hybrid extents+bitmap rb tree for free space
Btrfs: Fix crash on read failures at mount
Btrfs: remove of redundant btrfs_header_level
Btrfs: adjust NULL test
Btrfs: Remove broken sanity check from btrfs_rmap_block()
Btrfs: convert nested spin_lock_irqsave to spin_lock
Btrfs: make sure all dirty blocks are written at commit time
Btrfs: fix locking issue in btrfs_find_next_key
Btrfs: fix double increment of path->slots[0] in btrfs_next_leaf
...
Move the call to BUG_ON to before the dereference of the tested value.
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT
This will make hardirq.h inclusion cheaper for every PREEMPT=n config
(which includes allmodconfig/allyesconfig, BTW)
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: fix error message formatting
Btrfs: fix use after free in btrfs_start_workers fail path
Btrfs: honor nodatacow/sum mount options for new files
Btrfs: update backrefs while dropping snapshot
Btrfs: account for space we may use in fallocate
Btrfs: fix the file clone ioctl for preallocated extents
Btrfs: don't log the inode in file_write while growing the file
The btrfs attr patches unconditionally inherited the inode flags field
without honoring nodatacow and nodatasum. This fix makes sure
we properly record the nodatacow/sum mount options in new inodes.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Using Eric Sandeen's xfstest for fallocate, you can easily trigger a ENOSPC
panic on btrfs. This is because we do not account for data we may use when
doing the fallocate. This patch fixes the problem by properly reserving space,
and then just freeing it when we are done. The reservation stuff was made with
delalloc in mind, so its a little crude for this case, but it keeps the box
from panicing.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Add support for the standard attributes set via chattr and read via
lsattr. Currently we store the attributes in the flags value in
the btrfs inode, but I wonder whether we should split it into two so
that we don't have to keep converting between the two formats.
Remove the btrfs_clear_flag/btrfs_set_flag/btrfs_test_flag macros
as they were confusing the existing code and got in the way of the
new additions.
Also add the FS_IOC_GETVERSION ioctl for getting i_generation as it's
trivial.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.
When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one. At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.
The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root. This commit reduces the
transaction overhead by avoiding the need for dead root records.
When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.
This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.
We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.
This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.
This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.
This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.
The improved balancing code scales significantly better with a large
number of snapshots.
This is a very large commit and was written in a number of
pieces. But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
These debugging WARN_ONs make too much console noise during regular
IO failures. An IO failure will still generate a number of messages
as we verify checksums etc, but these two are not needed.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This flag is used to decide when we need to send a given file through
the ordered code to make sure it is fully written before a transaction
commits. It was not being properly set to zero when the inode was
being setup.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This changes btrfs_read_locked_inode() to peek ahead in the btree for acl items.
If it is certain a given inode has no acls, it will set the in memory acl
fields to null to avoid acl lookups completely.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Linus noticed the btrfs code to cache acls wasn't properly caching
a NULL acl when the inode didn't have any acls. This meant the common
case of no acls resulted in expensive btree searches every time the
kernel checked permissions (which is quite often).
This is a modified version of Linus' original patch:
Properly set initial acl fields to BTRFS_ACL_NOT_CACHED in the inode.
This forces an acl lookup when permission checks are done.
Fix btrfs_get_acl to avoid lookups and locking when the inode acls fields
are set to null.
Fix btrfs_get_acl to use the right return value from __btrfs_getxattr
when deciding to cache a NULL acl. It was storing a NULL acl when
__btrfs_getxattr return -ENOENT, but __btrfs_getxattr was actually returning
-ENODATA for this case.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Btrfs has printks for various IO errors, including bad checksums and
mismatches between what we expect the block headers to contain and what
we actually find on the disk.
Longer term we need a real reporting mechanism for this, but for now
printk is going to have to do.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The btrfs fallocate call takes an extent lock on the entire range
being fallocated, and then runs through insert_reserved_extent on each
extent as they are allocated.
The problem with this is that btrfs_drop_extents may decide to try
and take the same extent lock fallocate was already holding. The solution
used here is to push down knowledge of the range that is already locked
going into btrfs_drop_extents.
It turns out that at least one other caller had the same bug.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Btrfs fallocate was incorrectly starting a transaction with a lock held
on the extent_io tree for the file, which could deadlock. Strictly
speaking it was using join_transaction which would be safe, but it is better
to move the transaction outside of the lock.
When preallocated extents are overwritten, btrfs_mark_buffer_dirty was
being called on an unlocked buffer. This was triggering an assertion and
oops because the lock is supposed to be held.
The bug was calling btrfs_mark_buffer_dirty on a leaf after btrfs_del_item had
been run. btrfs_del_item takes care of dirtying things, so the solution is a
to skip the btrfs_mark_buffer_dirty call in this case.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: BUG to BUG_ON changes
Btrfs: remove dead code
Btrfs: remove dead code
Btrfs: fix typos in comments
Btrfs: remove unused ftrace include
Btrfs: fix __ucmpdi2 compile bug on 32 bit builds
Btrfs: free inode struct when btrfs_new_inode fails
Btrfs: fix race in worker_loop
Btrfs: add flushoncommit mount option
Btrfs: notreelog mount option
Btrfs: introduce btrfs_show_options
Btrfs: rework allocation clustering
Btrfs: Optimize locking in btrfs_next_leaf()
Btrfs: break up btrfs_search_slot into smaller pieces
Btrfs: kill the pinned_mutex
Btrfs: kill the block group alloc mutex
Btrfs: clean up find_free_extent
Btrfs: free space cache cleanups
Btrfs: unplug in the async bio submission threads
Btrfs: keep processing bios for a given bdev if our proc is batching
btrfs_new_inode doesn't call iput to free the inode
when it fails.
Signed-off-by: Shen Feng <shen@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: try to free metadata pages when we free btree blocks
Btrfs: add extra flushing for renames and truncates
Btrfs: make sure btrfs_update_delayed_ref doesn't increase ref_mod
Btrfs: optimize fsyncs on old files
Btrfs: tree logging unlink/rename fixes
Btrfs: Make sure i_nlink doesn't hit zero too soon during log replay
Btrfs: limit balancing work while flushing delayed refs
Btrfs: readahead checksums during btrfs_finish_ordered_io
Btrfs: leave btree locks spinning more often
Btrfs: Only let very young transactions grow during commit
Btrfs: Check for a blocking lock before taking the spin
Btrfs: reduce stack in cow_file_range
Btrfs: reduce stalls during transaction commit
Btrfs: process the delayed reference queue in clusters
Btrfs: try to cleanup delayed refs while freeing extents
Btrfs: reduce stack usage in some crucial tree balancing functions
Btrfs: do extent allocation and reference count updates in the background
Btrfs: don't preallocate metadata blocks during btrfs_search_slot
page_mkwrite is called with neither the page lock nor the ptl held. This
means a page can be concurrently truncated or invalidated out from
underneath it. Callers are supposed to prevent truncate races themselves,
however previously the only thing they can do in case they hit one is to
raise a SIGBUS. A sigbus is wrong for the case that the page has been
invalidated or truncated within i_size (eg. hole punched). Callers may
also have to perform memory allocations in this path, where again, SIGBUS
would be wrong.
The previous patch ("mm: page_mkwrite change prototype to match fault")
made it possible to properly specify errors. Convert the generic buffer.c
code and btrfs to return sane error values (in the case of page removed
from pagecache, VM_FAULT_NOPAGE will cause the fault handler to exit
without doing anything, and the fault will be retried properly).
This fixes core code, and converts btrfs as a template/example. All other
filesystems defining their own page_mkwrite should be fixed in a similar
manner.
Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change the page_mkwrite prototype to take a struct vm_fault, and return
VM_FAULT_xxx flags. There should be no functional change.
This makes it possible to return much more detailed error information to
the VM (and also can provide more information eg. virtual_address to the
driver, which might be important in some special cases).
This is required for a subsequent fix. And will also make it easier to
merge page_mkwrite() with fault() in future.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
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>
This reads in blocks in the checksum btree before starting the
transaction in btrfs_finish_ordered_io. It makes it much more likely
we'll be able to do operations inside the transaction without
needing any btree reads, which limits transaction latencies overall.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs_mark_buffer dirty would set dirty bits in the extent_io tree
for the buffers it was dirtying. This may require a kmalloc and it
was not atomic. So, anyone who called btrfs_mark_buffer_dirty had to
set any btree locks they were holding to blocking first.
This commit changes dirty tracking for extent buffers to just use a flag
in the extent buffer. Now that we have one and only one extent buffer
per page, this can be safely done without losing dirty bits along the way.
This also introduces a path->leave_spinning flag that callers of
btrfs_search_slot can use to indicate they will properly deal with a
path returned where all the locks are spinning instead of blocking.
Many of the btree search callers now expect spinning paths,
resulting in better btree concurrency overall.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The fs/btrfs/inode.c code to run delayed allocation during writout
needed some stack usage optimization. This is the first pass, it does
the check for compression earlier on, which allows us to do the common
(no compression) case higher up in the call chain.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
To avoid deadlocks and reduce latencies during some critical operations, some
transaction writers are allowed to jump into the running transaction and make
it run a little longer, while others sit around and wait for the commit to
finish.
This is a bit unfair, especially when the callers that jump in do a bunch
of IO that makes all the others procs on the box wait. This commit
reduces the stalls this produces by pre-reading file extent pointers
during btrfs_finish_ordered_io before the transaction is joined.
It also tunes the drop_snapshot code to politely wait for transactions
that have started writing out their delayed refs to finish. This avoids
new delayed refs being flooded into the queue while we're trying to
close off the transaction.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This is a step in the direction of better -ENOSPC handling. Instead of
checking the global bytes counter we check the space_info bytes counters to
make sure we have enough space.
If we don't we go ahead and try to allocate a new chunk, and then if that fails
we return -ENOSPC. This patch adds two counters to btrfs_space_info,
bytes_delalloc and bytes_may_use.
bytes_delalloc account for extents we've actually setup for delalloc and will
be allocated at some point down the line.
bytes_may_use is to keep track of how many bytes we may use for delalloc at
some point. When we actually set the extent_bit for the delalloc bytes we
subtract the reserved bytes from the bytes_may_use counter. This keeps us from
not actually being able to allocate space for any delalloc bytes.
Signed-off-by: Josef Bacik <jbacik@redhat.com>
btrfs_init_path was initially used when the path objects were on the
stack. Now all the work is done by btrfs_alloc_path and btrfs_init_path
isn't required.
This patch removes it, and just uses kmem_cache_zalloc to zero out the object.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs_releasepage may call kmem_cache_alloc indirectly,
and provide same GFP flags it gets to kmem_cache_alloc.
So it's possible to use __GFP_HIGHMEM with the slab
allocator.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
The S_ISGID check in btrfs_new_inode caused an oops during subvol creation
because sometimes the dir is null.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs_truncate_inode_items is setup to stop doing btree searches when
it has finished removing the items for the inode. It used to detect the
end of the inode by looking for an objectid that didn't match the
one we were searching for.
But, this would result in an extra search through the btree, which
adds extra balancing and cow costs to the operation.
This commit adds a check to see if we found the inode item, which means
we can stop searching early.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The compression code had some checks to make sure we were only
compressing bytes inside of i_size, but it wasn't catching every
case. To make things worse, some incorrect math about the number
of bytes remaining would make it try to compress more pages than the
file really had.
The fix used here is to fall back to the non-compression code in this
case, which does all the proper cleanup of delalloc and other accounting.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Before this patch, new files/dirs would ignore the SGID bit on their
parent directory and always be owned by the creating user's uid/gid.
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Every transaction in btrfs creates a new snapshot, and then schedules the
snapshot from the last transaction for deletion. Snapshot deletion
works by walking down the btree and dropping the reference counts
on each btree block during the walk.
If if a given leaf or node has a reference count greater than one,
the reference count is decremented and the subtree pointed to by that
node is ignored.
If the reference count is one, walking continues down into that node
or leaf, and the references of everything it points to are decremented.
The old code would try to work in small pieces, walking down the tree
until it found the lowest leaf or node to free and then returning. This
was very friendly to the rest of the FS because it didn't have a huge
impact on other operations.
But it wouldn't always keep up with the rate that new commits added new
snapshots for deletion, and it wasn't very optimal for the extent
allocation tree because it wasn't finding leaves that were close together
on disk and processing them at the same time.
This changes things to walk down to a level 1 node and then process it
in bulk. All the leaf pointers are sorted and the leaves are dropped
in order based on their extent number.
The extent allocation tree and commit code are now fast enough for
this kind of bulk processing to work without slowing the rest of the FS
down. Overall it does less IO and is better able to keep up with
snapshot deletions under high load.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Most of the btrfs metadata operations can be protected by a spinlock,
but some operations still need to schedule.
So far, btrfs has been using a mutex along with a trylock loop,
most of the time it is able to avoid going for the full mutex, so
the trylock loop is a big performance gain.
This commit is step one for getting rid of the blocking locks entirely.
btrfs_tree_lock takes a spinlock, and the code explicitly switches
to a blocking lock when it starts an operation that can schedule.
We'll be able get rid of the blocking locks in smaller pieces over time.
Tracing allows us to find the most common cause of blocking, so we
can start with the hot spots first.
The basic idea is:
btrfs_tree_lock() returns with the spin lock held
btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in
the extent buffer flags, and then drops the spin lock. The buffer is
still considered locked by all of the btrfs code.
If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops
the spin lock and waits on a wait queue for the blocking bit to go away.
Much of the code that needs to set the blocking bit finishes without actually
blocking a good percentage of the time. So, an adaptive spin is still
used against the blocking bit to avoid very high context switch rates.
btrfs_clear_lock_blocking() clears the blocking bit and returns
with the spinlock held again.
btrfs_tree_unlock() can be called on either blocking or spinning locks,
it does the right thing based on the blocking bit.
ctree.c has a helper function to set/clear all the locked buffers in a
path as blocking.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Add call to LSM security initialization and save
resulting security xattr for new inodes.
Add xattr support to symlink inode ops.
Set inode->i_op for existing special files.
Signed-off-by: jim owens <jowens@hp.com>
After btrfs_readdir has gone through all the directory items, it
sets the directory f_pos to the largest possible int. This way
applications that mix readdir with creating new files don't
end up in an endless loop finding the new directory items as they go.
It was a workaround for a bug in git, but the assumption was that if git
could make this looping mistake than it would be a common problem.
The largest possible int chosen was INT_LIMIT(typeof(file->f_pos),
and it is possible for that to be a larger number than 32 bit glibc
expects to come out of readdir.
This patches switches that to INT_LIMIT(off_t), which should keep
applications happy on 32 and 64 bit machines.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Now that bmap support is gone, this is the only way to get extent
mappings for userland. These are still not valid for IO, but they
can tell us if a file has holes or how much fragmentation there is.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Swapfiles use bmap to build a list of extents belonging to the file,
and they assume these extents won't change over the life of the file.
They also use resulting list to do IO directly to the block device.
This causes problems for btrfs in a few ways:
btrfs returns logical block numbers through bmap, and these are not suitable
for IO. They might translate to different devices, raid etc.
COW means that file block mappings are going to change frequently.
Using swapfiles on btrfs will lead to corruption, so we're avoiding the
problem for now by dropping bmap support entirely. A later commit
will add fiemap support for people that really want to know how
a file is laid out.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Merge list_for_each* and list_entry to list_for_each_entry*
Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Andi Kleen