Btrfs doesn't track superblocks with extent records so there is nothing
persistent on-disk to indicate that those blocks are in use. We track
the superblocks in memory to ensure they don't get used by removing them
from the free space cache when we load a block group from disk. Prior
to 47ab2a6c6a (Btrfs: remove empty block groups automatically), that
was fine since the block group would never be reclaimed so the superblock
was always safe. Once we started removing the empty block groups, we
were protected by the fact that discards weren't being properly issued
for unused space either via FITRIM or -odiscard. The block groups were
still being released, but the blocks remained on disk.
In order to properly discard unused block groups, we need to filter out
the superblocks from the discard range. Superblocks are located at fixed
locations on each device, so it makes sense to filter them out in
btrfs_issue_discard, which is used by both -odiscard and FITRIM.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
It's possible, though unexpected, to pass unaligned offsets and lengths
to btrfs_issue_discard. We then shift the offset/length values to sector
units. If an unaligned offset has been passed, it will result in the
entire sector being discarded, possibly losing data. An unaligned
length is safe but we'll end up returning an inaccurate number of
discarded bytes.
This patch aligns the offset to the 512B boundary, adjusts the length,
and warns, since we shouldn't be discarding on an offset that isn't
aligned with our sector size.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Initially this will just be the length argument passed to it,
but the following patches will adjust that to reflect re-alignment
and skipped blocks.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Omar reported that after commit 4fbcdf6694 ("Btrfs: fix -ENOSPC when
finishing block group creation"), introduced in 4.2-rc1, the following
test was failing due to exhaustion of the system array in the superblock:
#!/bin/bash
truncate -s 100T big.img
mkfs.btrfs big.img
mount -o loop big.img /mnt/loop
num=5
sz=10T
for ((i = 0; i < $num; i++)); do
echo fallocate $i $sz
fallocate -l $sz /mnt/loop/testfile$i
done
btrfs filesystem sync /mnt/loop
for ((i = 0; i < $num; i++)); do
echo rm $i
rm /mnt/loop/testfile$i
btrfs filesystem sync /mnt/loop
done
umount /mnt/loop
This made btrfs_add_system_chunk() fail with -EFBIG due to excessive
allocation of system block groups. This happened because the test creates
a large number of data block groups per transaction and when committing
the transaction we start the writeout of the block group caches for all
the new new (dirty) block groups, which results in pre-allocating space
for each block group's free space cache using the same transaction handle.
That in turn often leads to creation of more block groups, and all get
attached to the new_bgs list of the same transaction handle to the point
of getting a list with over 1500 elements, and creation of new block groups
leads to the need of reserving space in the chunk block reserve and often
creating a new system block group too.
So that made us quickly exhaust the chunk block reserve/system space info,
because as of the commit mentioned before, we do reserve space for each
new block group in the chunk block reserve, unlike before where we would
not and would at most allocate one new system block group and therefore
would only ensure that there was enough space in the system space info to
allocate 1 new block group even if we ended up allocating thousands of
new block groups using the same transaction handle. That worked most of
the time because the computed required space at check_system_chunk() is
very pessimistic (assumes a chunk tree height of BTRFS_MAX_LEVEL/8 and
that all nodes/leafs in a path will be COWed and split) and since the
updates to the chunk tree all happen at btrfs_create_pending_block_groups
it is unlikely that a path needs to be COWed more than once (unless
writepages() for the btree inode is called by mm in between) and that
compensated for the need of creating any new nodes/leads in the chunk
tree.
So fix this by ensuring we don't accumulate a too large list of new block
groups in a transaction's handles new_bgs list, inserting/updating the
chunk tree for all accumulated new block groups and releasing the unused
space from the chunk block reserve whenever the list becomes sufficiently
large. This is a generic solution even though the problem currently can
only happen when starting the writeout of the free space caches for all
dirty block groups (btrfs_start_dirty_block_groups()).
Reported-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
sorry I indented to use btrfs_err() and I have no idea
how btrfs_error() got there.
infact I was thinking about these kind of oversights
since these two func are too closely named.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Liu Bo <bo.li.liu@oracle.com> reported a lockdep warning of
delayed_iput_sem in xfstests generic/241:
[ 2061.345955] =============================================
[ 2061.346027] [ INFO: possible recursive locking detected ]
[ 2061.346027] 4.1.0+ #268 Tainted: G W
[ 2061.346027] ---------------------------------------------
[ 2061.346027] btrfs-cleaner/3045 is trying to acquire lock:
[ 2061.346027] (&fs_info->delayed_iput_sem){++++..}, at:
[<ffffffff814063ab>] btrfs_run_delayed_iputs+0x6b/0x100
[ 2061.346027] but task is already holding lock:
[ 2061.346027] (&fs_info->delayed_iput_sem){++++..}, at: [<ffffffff814063ab>] btrfs_run_delayed_iputs+0x6b/0x100
[ 2061.346027] other info that might help us debug this:
[ 2061.346027] Possible unsafe locking scenario:
[ 2061.346027] CPU0
[ 2061.346027] ----
[ 2061.346027] lock(&fs_info->delayed_iput_sem);
[ 2061.346027] lock(&fs_info->delayed_iput_sem);
[ 2061.346027]
*** DEADLOCK ***
It is rarely happened, about 1/400 in my test env.
The reason is recursion of btrfs_run_delayed_iputs():
cleaner_kthread
-> btrfs_run_delayed_iputs() *1
-> get delayed_iput_sem lock *2
-> iput()
-> ...
-> btrfs_commit_transaction()
-> btrfs_run_delayed_iputs() *1
-> get delayed_iput_sem lock (dead lock) *2
*1: recursion of btrfs_run_delayed_iputs()
*2: warning of lockdep about delayed_iput_sem
When fs is in high stress, new iputs may added into fs_info->delayed_iputs
list when btrfs_run_delayed_iputs() is running, which cause
second btrfs_run_delayed_iputs() run into down_read(&fs_info->delayed_iput_sem)
again, and cause above lockdep warning.
Actually, it will not cause real problem because both locks are read lock,
but to avoid lockdep warning, we can do a fix.
Fix:
Don't do btrfs_run_delayed_iputs() in btrfs_commit_transaction() for
cleaner_kthread thread to break above recursion path.
cleaner_kthread is calling btrfs_run_delayed_iputs() explicitly in code,
and don't need to call btrfs_run_delayed_iputs() again in
btrfs_commit_transaction(), it also give us a bonus to avoid stack overflow.
Test:
No above lockdep warning after patch in 1200 generic/241 tests.
Reported-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
Using the clone ioctl (or extent_same ioctl, which calls the same extent
cloning function as well) we end up allowing copy an inline extent from
the source file into a non-zero offset of the destination file. This is
something not expected and that the btrfs code is not prepared to deal
with - all inline extents must be at a file offset equals to 0.
For example, the following excerpt of a test case for fstests triggers
a crash/BUG_ON() on a write operation after an inline extent is cloned
into a non-zero offset:
_scratch_mkfs >>$seqres.full 2>&1
_scratch_mount
# Create our test files. File foo has the same 2K of data at offset 4K
# as file bar has at its offset 0.
$XFS_IO_PROG -f -s -c "pwrite -S 0xaa 0 4K" \
-c "pwrite -S 0xbb 4k 2K" \
-c "pwrite -S 0xcc 8K 4K" \
$SCRATCH_MNT/foo | _filter_xfs_io
# File bar consists of a single inline extent (2K size).
$XFS_IO_PROG -f -s -c "pwrite -S 0xbb 0 2K" \
$SCRATCH_MNT/bar | _filter_xfs_io
# Now call the clone ioctl to clone the extent of file bar into file
# foo at its offset 4K. This made file foo have an inline extent at
# offset 4K, something which the btrfs code can not deal with in future
# IO operations because all inline extents are supposed to start at an
# offset of 0, resulting in all sorts of chaos.
# So here we validate that clone ioctl returns an EOPNOTSUPP, which is
# what it returns for other cases dealing with inlined extents.
$CLONER_PROG -s 0 -d $((4 * 1024)) -l $((2 * 1024)) \
$SCRATCH_MNT/bar $SCRATCH_MNT/foo
# Because of the inline extent at offset 4K, the following write made
# the kernel crash with a BUG_ON().
$XFS_IO_PROG -c "pwrite -S 0xdd 6K 2K" $SCRATCH_MNT/foo | _filter_xfs_io
status=0
exit
The stack trace of the BUG_ON() triggered by the last write is:
[152154.035903] ------------[ cut here ]------------
[152154.036424] kernel BUG at mm/page-writeback.c:2286!
[152154.036424] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[152154.036424] Modules linked in: btrfs dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse parport_pc acpi_cpu$
[152154.036424] CPU: 2 PID: 17873 Comm: xfs_io Tainted: G W 4.1.0-rc6-btrfs-next-11+ #2
[152154.036424] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[152154.036424] task: ffff880429f70990 ti: ffff880429efc000 task.ti: ffff880429efc000
[152154.036424] RIP: 0010:[<ffffffff8111a9d5>] [<ffffffff8111a9d5>] clear_page_dirty_for_io+0x1e/0x90
[152154.036424] RSP: 0018:ffff880429effc68 EFLAGS: 00010246
[152154.036424] RAX: 0200000000000806 RBX: ffffea0006a6d8f0 RCX: 0000000000000001
[152154.036424] RDX: 0000000000000000 RSI: ffffffff81155d1b RDI: ffffea0006a6d8f0
[152154.036424] RBP: ffff880429effc78 R08: ffff8801ce389fe0 R09: 0000000000000001
[152154.036424] R10: 0000000000002000 R11: ffffffffffffffff R12: ffff8800200dce68
[152154.036424] R13: 0000000000000000 R14: ffff8800200dcc88 R15: ffff8803d5736d80
[152154.036424] FS: 00007fbf119f6700(0000) GS:ffff88043d280000(0000) knlGS:0000000000000000
[152154.036424] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[152154.036424] CR2: 0000000001bdc000 CR3: 00000003aa555000 CR4: 00000000000006e0
[152154.036424] Stack:
[152154.036424] ffff8803d5736d80 0000000000000001 ffff880429effcd8 ffffffffa04e97c1
[152154.036424] ffff880429effd68 ffff880429effd60 0000000000000001 ffff8800200dc9c8
[152154.036424] 0000000000000001 ffff8800200dcc88 0000000000000000 0000000000001000
[152154.036424] Call Trace:
[152154.036424] [<ffffffffa04e97c1>] lock_and_cleanup_extent_if_need+0x147/0x18d [btrfs]
[152154.036424] [<ffffffffa04ea82c>] __btrfs_buffered_write+0x245/0x4c8 [btrfs]
[152154.036424] [<ffffffffa04ed14b>] ? btrfs_file_write_iter+0x150/0x3e0 [btrfs]
[152154.036424] [<ffffffffa04ed15a>] ? btrfs_file_write_iter+0x15f/0x3e0 [btrfs]
[152154.036424] [<ffffffffa04ed2c7>] btrfs_file_write_iter+0x2cc/0x3e0 [btrfs]
[152154.036424] [<ffffffff81165a4a>] __vfs_write+0x7c/0xa5
[152154.036424] [<ffffffff81165f89>] vfs_write+0xa0/0xe4
[152154.036424] [<ffffffff81166855>] SyS_pwrite64+0x64/0x82
[152154.036424] [<ffffffff81465197>] system_call_fastpath+0x12/0x6f
[152154.036424] Code: 48 89 c7 e8 0f ff ff ff 5b 41 5c 5d c3 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 89 fb e8 ae ef 00 00 49 89 c4 48 8b 03 a8 01 75 02 <0f> 0b 4d 85 e4 74 59 49 8b 3c 2$
[152154.036424] RIP [<ffffffff8111a9d5>] clear_page_dirty_for_io+0x1e/0x90
[152154.036424] RSP <ffff880429effc68>
[152154.242621] ---[ end trace e3d3376b23a57041 ]---
Fix this by returning the error EOPNOTSUPP if an attempt to copy an
inline extent into a non-zero offset happens, just like what is done for
other scenarios that would require copying/splitting inline extents,
which were introduced by the following commits:
00fdf13a2e ("Btrfs: fix a crash of clone with inline extents's split")
3f9e3df8da ("btrfs: replace error code from btrfs_drop_extents")
Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
When we have an extent that got N references removed and N new references
added in the same transaction, we must run the insertion of the references
first because otherwise the last removed reference will remove the extent
item from the extent tree, resulting in a failure for the insertions.
This is a regression introduced in the 4.2-rc1 release and this fix just
brings back the behaviour of selecting reference additions before any
reference removals.
The following test case for fstests reproduces the issue:
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
tmp=/tmp/$$
status=1 # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15
_cleanup()
{
_cleanup_flakey
rm -f $tmp.*
}
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
. ./common/dmflakey
# real QA test starts here
_need_to_be_root
_supported_fs btrfs
_supported_os Linux
_require_scratch
_require_dm_flakey
_require_cloner
_require_metadata_journaling $SCRATCH_DEV
rm -f $seqres.full
_scratch_mkfs >>$seqres.full 2>&1
_init_flakey
_mount_flakey
# Create prealloc extent covering range [160K, 620K[
$XFS_IO_PROG -f -c "falloc 160K 460K" $SCRATCH_MNT/foo
# Now write to the last 80K of the prealloc extent plus 40K to the unallocated
# space that immediately follows it. This creates a new extent of 40K that spans
# the range [620K, 660K[.
$XFS_IO_PROG -c "pwrite -S 0xaa 540K 120K" $SCRATCH_MNT/foo | _filter_xfs_io
# At this point, there are now 2 back references to the prealloc extent in our
# extent tree. Both are for our file offset 160K and one relates to a file
# extent item with a data offset of 0 and a length of 380K, while the other
# relates to a file extent item with a data offset of 380K and a length of 80K.
# Make sure everything done so far is durably persisted (all back references are
# in the extent tree, etc).
sync
# Now clone all extents of our file that cover the offset 160K up to its eof
# (660K at this point) into itself at offset 2M. This leaves a hole in the file
# covering the range [660K, 2M[. The prealloc extent will now be referenced by
# the file twice, once for offset 160K and once for offset 2M. The 40K extent
# that follows the prealloc extent will also be referenced twice by our file,
# once for offset 620K and once for offset 2M + 460K.
$CLONER_PROG -s $((160 * 1024)) -d $((2 * 1024 * 1024)) -l 0 $SCRATCH_MNT/foo \
$SCRATCH_MNT/foo
# Now create one new extent in our file with a size of 100Kb. It will span the
# range [3M, 3M + 100K[. It also will cause creation of a hole spanning the
# range [2M + 460K, 3M[. Our new file size is 3M + 100K.
$XFS_IO_PROG -c "pwrite -S 0xbb 3M 100K" $SCRATCH_MNT/foo | _filter_xfs_io
# At this point, there are now (in memory) 4 back references to the prealloc
# extent.
#
# Two of them are for file offset 160K, related to file extent items
# matching the file offsets 160K and 540K respectively, with data offsets of
# 0 and 380K respectively, and with lengths of 380K and 80K respectively.
#
# The other two references are for file offset 2M, related to file extent items
# matching the file offsets 2M and 2M + 380K respectively, with data offsets of
# 0 and 380K respectively, and with lengths of 389K and 80K respectively.
#
# The 40K extent has 2 back references, one for file offset 620K and the other
# for file offset 2M + 460K.
#
# The 100K extent has a single back reference and it relates to file offset 3M.
# Now clone our 100K extent into offset 600K. That offset covers the last 20K
# of the prealloc extent, the whole 40K extent and 40K of the hole starting at
# offset 660K.
$CLONER_PROG -s $((3 * 1024 * 1024)) -d $((600 * 1024)) -l $((100 * 1024)) \
$SCRATCH_MNT/foo $SCRATCH_MNT/foo
# At this point there's only one reference to the 40K extent, at file offset
# 2M + 460K, we have 4 references for the prealloc extent (2 for file offset
# 160K and 2 for file offset 2M) and 2 references for the 100K extent (1 for
# file offset 3M and a new one for file offset 600K).
# Now fsync our file to make all its new data and metadata updates are durably
# persisted and present if a power failure/crash happens after a successful
# fsync and before the next transaction commit.
$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo
echo "File digest before power failure:"
md5sum $SCRATCH_MNT/foo | _filter_scratch
# Silently drop all writes and ummount to simulate a crash/power failure.
_load_flakey_table $FLAKEY_DROP_WRITES
_unmount_flakey
# Allow writes again, mount to trigger log replay and validate file contents.
# During log replay, the btrfs delayed references implementation used to run the
# deletion of back references before the addition of new back references, which
# made the addition fail as it didn't find the key in the extent tree that it
# was looking for. The failure triggered by this test was related to the 40K
# extent, which got 1 reference dropped and 1 reference added during the fsync
# log replay - when running the delayed references at transaction commit time,
# btrfs was applying the deletion before the insertion, resulting in a failure
# of the insertion that ended up turning the fs into read-only mode.
_load_flakey_table $FLAKEY_ALLOW_WRITES
_mount_flakey
echo "File digest after log replay:"
md5sum $SCRATCH_MNT/foo | _filter_scratch
_unmount_flakey
status=0
exit
This issue turned the filesystem into read-only mode (current transaction
aborted) and produced the following traces:
[ 8247.578385] ------------[ cut here ]------------
[ 8247.579947] WARNING: CPU: 0 PID: 11341 at fs/btrfs/extent-tree.c:1547 lookup_inline_extent_backref+0x17d/0x45d [btrfs]()
(...)
[ 8247.601697] Call Trace:
[ 8247.602222] [<ffffffff8145f077>] dump_stack+0x4f/0x7b
[ 8247.604320] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb
[ 8247.605488] [<ffffffffa0506c8d>] ? lookup_inline_extent_backref+0x17d/0x45d [btrfs]
[ 8247.608226] [<ffffffffa0506c8d>] lookup_inline_extent_backref+0x17d/0x45d [btrfs]
[ 8247.617061] [<ffffffffa0507957>] insert_inline_extent_backref+0x41/0xb2 [btrfs]
[ 8247.621856] [<ffffffffa0507c4f>] __btrfs_inc_extent_ref+0x8c/0x20a [btrfs]
[ 8247.624366] [<ffffffffa050ee60>] __btrfs_run_delayed_refs+0xb0c/0xd49 [btrfs]
[ 8247.626176] [<ffffffffa0510dcd>] btrfs_run_delayed_refs+0x6d/0x1d4 [btrfs]
[ 8247.627435] [<ffffffff81155c9b>] ? __cache_free+0x4a7/0x4b6
[ 8247.628531] [<ffffffffa0520482>] btrfs_commit_transaction+0x4c/0xa20 [btrfs]
(...)
[ 8247.648430] ---[ end trace 2461e55f92c2ac2d ]---
[ 8247.727263] WARNING: CPU: 3 PID: 11341 at fs/btrfs/extent-tree.c:2771 btrfs_run_delayed_refs+0xa4/0x1d4 [btrfs]()
[ 8247.728954] BTRFS: Transaction aborted (error -5)
(...)
[ 8247.760866] Call Trace:
[ 8247.761534] [<ffffffff8145f077>] dump_stack+0x4f/0x7b
[ 8247.764271] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb
[ 8247.767582] [<ffffffffa0510e04>] ? btrfs_run_delayed_refs+0xa4/0x1d4 [btrfs]
[ 8247.769373] [<ffffffff8104b410>] warn_slowpath_fmt+0x46/0x48
[ 8247.770836] [<ffffffffa0510e04>] btrfs_run_delayed_refs+0xa4/0x1d4 [btrfs]
[ 8247.772532] [<ffffffff81155c9b>] ? __cache_free+0x4a7/0x4b6
[ 8247.773664] [<ffffffffa0520482>] btrfs_commit_transaction+0x4c/0xa20 [btrfs]
[ 8247.775047] [<ffffffff81087310>] ? trace_hardirqs_on+0xd/0xf
[ 8247.776176] [<ffffffff81155dd5>] ? kmem_cache_free+0x12b/0x189
[ 8247.777427] [<ffffffffa055a920>] btrfs_recover_log_trees+0x2da/0x33d [btrfs]
[ 8247.778575] [<ffffffffa055898e>] ? replay_one_extent+0x4fc/0x4fc [btrfs]
[ 8247.779838] [<ffffffffa051e265>] open_ctree+0x1cc0/0x201a [btrfs]
[ 8247.781020] [<ffffffff81120f48>] ? register_shrinker+0x56/0x81
[ 8247.782285] [<ffffffffa04fb12c>] btrfs_mount+0x5f0/0x734 [btrfs]
(...)
[ 8247.793394] ---[ end trace 2461e55f92c2ac2e ]---
[ 8247.794276] BTRFS: error (device dm-0) in btrfs_run_delayed_refs:2771: errno=-5 IO failure
[ 8247.797335] BTRFS: error (device dm-0) in btrfs_replay_log:2375: errno=-5 IO failure (Failed to recover log tree)
Fixes: c6fc245499 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Acked-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
When we call btrfs_commit_transaction(), we splice the list "ordered"
of our transaction handle into the transaction's "pending_ordered"
list, but we don't re-initialize the "ordered" list of our transaction
handle, this means it still points to the same elements it used to
before the splice. Then we check if the current transaction's state is
>= TRANS_STATE_COMMIT_START and if it is we end up calling
btrfs_end_transaction() which simply splices again the "ordered" list
of our handle into the transaction's "pending_ordered" list, leaving
multiple pointers to the same ordered extents which results in list
corruption when we are iterating, removing and freeing ordered extents
at btrfs_wait_pending_ordered(), resulting in access to dangling
pointers / use-after-free issues.
Similarly, btrfs_end_transaction() can end up in some cases calling
btrfs_commit_transaction(), and both did a list splice of the transaction
handle's "ordered" list into the transaction's "pending_ordered" without
re-initializing the handle's "ordered" list, resulting in exactly the
same problem.
This produces the following warning on a kernel with linked list
debugging enabled:
[109749.265416] ------------[ cut here ]------------
[109749.266410] WARNING: CPU: 7 PID: 324 at lib/list_debug.c:59 __list_del_entry+0x5a/0x98()
[109749.267969] list_del corruption. prev->next should be ffff8800ba087e20, but was fffffff8c1f7c35d
(...)
[109749.287505] Call Trace:
[109749.288135] [<ffffffff8145f077>] dump_stack+0x4f/0x7b
[109749.298080] [<ffffffff81095de5>] ? console_unlock+0x356/0x3a2
[109749.331605] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb
[109749.334849] [<ffffffff81260642>] ? __list_del_entry+0x5a/0x98
[109749.337093] [<ffffffff8104b410>] warn_slowpath_fmt+0x46/0x48
[109749.337847] [<ffffffff81260642>] __list_del_entry+0x5a/0x98
[109749.338678] [<ffffffffa053e8bf>] btrfs_wait_pending_ordered+0x46/0xdb [btrfs]
[109749.340145] [<ffffffffa058a65f>] ? __btrfs_run_delayed_items+0x149/0x163 [btrfs]
[109749.348313] [<ffffffffa054077d>] btrfs_commit_transaction+0x36b/0xa10 [btrfs]
[109749.349745] [<ffffffff81087310>] ? trace_hardirqs_on+0xd/0xf
[109749.350819] [<ffffffffa055370d>] btrfs_sync_file+0x36f/0x3fc [btrfs]
[109749.351976] [<ffffffff8118ec98>] vfs_fsync_range+0x8f/0x9e
[109749.360341] [<ffffffff8118ecc3>] vfs_fsync+0x1c/0x1e
[109749.368828] [<ffffffff8118ee1d>] do_fsync+0x34/0x4e
[109749.369790] [<ffffffff8118f045>] SyS_fsync+0x10/0x14
[109749.370925] [<ffffffff81465197>] system_call_fastpath+0x12/0x6f
[109749.382274] ---[ end trace 48e0d07f7c03d95a ]---
On a non-debug kernel this leads to invalid memory accesses, causing a
crash. Fix this by using list_splice_init() instead of list_splice() in
btrfs_commit_transaction() and btrfs_end_transaction().
Cc: stable@vger.kernel.org
Fixes: 50d9aa99bd ("Btrfs: make sure logged extents complete in the current transaction V3"
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
We were allocating memory with memdup_user() but we were never releasing
that memory. This affected pretty much every call to the ioctl, whether
it deduplicated extents or not.
This issue was reported on IRC by Julian Taylor and on the mailing list
by Marcel Ritter, credit goes to them for finding the issue.
Reported-by: Julian Taylor <jtaylor.debian@googlemail.com>
Reported-by: Marcel Ritter <ritter.marcel@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Mark Fasheh <mfasheh@suse.de>
If the no_holes feature is enabled, we attempt to shrink a file to a size
that ends up in the middle of a hole and we don't have any file extent
items in the fs/subvol tree that go beyond the new file size (or any
ordered extents that will insert such file extent items), we end up not
updating the inode's disk_i_size, we only update the inode's i_size.
This means that after unmounting and mounting the filesystem, or after
the inode is evicted and reloaded, its i_size ends up being incorrect
(an inode's i_size is set to the disk_i_size field when an inode is
loaded). This happens when btrfs_truncate_inode_items() doesn't find
any file extent items to drop - in this case it never makes a call to
btrfs_ordered_update_i_size() in order to update the inode's disk_i_size.
Example reproducer:
$ mkfs.btrfs -O no-holes -f /dev/sdd
$ mount /dev/sdd /mnt
# Create our test file with some data and durably persist it.
$ xfs_io -f -c "pwrite -S 0xaa 0 128K" /mnt/foo
$ sync
# Append some data to the file, increasing its size, and leave a hole
# between the old size and the start offset if the following write. So
# our file gets a hole in the range [128Kb, 256Kb[.
$ xfs_io -c "truncate 160K" /mnt/foo
# We expect to see our file with a size of 160Kb, with the first 128Kb
# of data all having the value 0xaa and the remaining 32Kb of data all
# having the value 0x00.
$ od -t x1 /mnt/foo
0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
*
0400000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0500000
# Now cleanly unmount and mount again the filesystem.
$ umount /mnt
$ mount /dev/sdd /mnt
# We expect to get the same result as before, a file with a size of
# 160Kb, with the first 128Kb of data all having the value 0xaa and the
# remaining 32Kb of data all having the value 0x00.
$ od -t x1 /mnt/foo
0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
*
0400000
In the example above the file size/data do not match what they were before
the remount.
Fix this by always calling btrfs_ordered_update_i_size() with a size
matching the size the file was truncated to if btrfs_truncate_inode_items()
is not called for a log tree and no file extent items were dropped. This
ensures the same behaviour as when the no_holes feature is not enabled.
A test case for fstests follows soon.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
btrfs_force_chunk_alloc() return 1 for allocation chunk successfully.
This problem exists since commit c87f08ca4.
With this patch, we might fix some enospc problems for balances.
Signed-off-by: Wang Shilong <wangshilong1991@gmail.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
While running generic/019, dmesg got several warnings from
btrfs_free_reserved_data_space().
Test generic/019 produces some disk failures so sumbit dio will get errors,
in which case, btrfs_direct_IO() goes to the error handling and free
bytes_may_use, but the problem is that bytes_may_use has been free'd
during get_block().
This adds a runtime flag to show if we've gone through get_block(), if so,
don't do the cleanup work.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
The hang is uncoverd by generic/019.
btrfs_endio_direct_write() skips the "finish_ordered_fn" part when it hits
an error, thus those added ordered extents will never get processed, which
block processes that waiting for them via btrfs_start_ordered_extent().
This fixes the above, and meanwhile finish_ordered_fn will do the space
accounting work.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
The comment was not correct about the part where it says the endio
callback of the bio might have not yet been called - update it
to mention that by that time the endio callback execution might
still be in progress only.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
If we fail to submit a bio for a direct IO request, we were grabbing the
corresponding ordered extent and decrementing its reference count twice,
once for our lookup reference and once for the ordered tree reference.
This was a problem because it caused the ordered extent to be freed
without removing it from the ordered tree and any lists it might be
attached to, leaving dangling pointers to the ordered extent around.
Example trace with CONFIG_DEBUG_PAGEALLOC=y:
[161779.858707] BUG: unable to handle kernel paging request at 0000000087654330
[161779.859983] IP: [<ffffffff8124ca68>] rb_prev+0x22/0x3b
[161779.860636] PGD 34d818067 PUD 0
[161779.860636] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
(...)
[161779.860636] Call Trace:
[161779.860636] [<ffffffffa06b36a6>] __tree_search+0xd9/0xf9 [btrfs]
[161779.860636] [<ffffffffa06b3708>] tree_search+0x42/0x63 [btrfs]
[161779.860636] [<ffffffffa06b4868>] ? btrfs_lookup_ordered_range+0x2d/0xa5 [btrfs]
[161779.860636] [<ffffffffa06b4873>] btrfs_lookup_ordered_range+0x38/0xa5 [btrfs]
[161779.860636] [<ffffffffa06aab8e>] btrfs_get_blocks_direct+0x11b/0x615 [btrfs]
[161779.860636] [<ffffffff8119727f>] do_blockdev_direct_IO+0x5ff/0xb43
[161779.860636] [<ffffffffa06aaa73>] ? btrfs_page_exists_in_range+0x1ad/0x1ad [btrfs]
[161779.860636] [<ffffffffa06a2c9a>] ? btrfs_get_extent_fiemap+0x1bc/0x1bc [btrfs]
[161779.860636] [<ffffffff811977f5>] __blockdev_direct_IO+0x32/0x34
[161779.860636] [<ffffffffa06a2c9a>] ? btrfs_get_extent_fiemap+0x1bc/0x1bc [btrfs]
[161779.860636] [<ffffffffa06a10ae>] btrfs_direct_IO+0x198/0x21f [btrfs]
[161779.860636] [<ffffffffa06a2c9a>] ? btrfs_get_extent_fiemap+0x1bc/0x1bc [btrfs]
[161779.860636] [<ffffffff81112ca1>] generic_file_direct_write+0xb3/0x128
[161779.860636] [<ffffffffa06affaa>] ? btrfs_file_write_iter+0x15f/0x3e0 [btrfs]
[161779.860636] [<ffffffffa06b004c>] btrfs_file_write_iter+0x201/0x3e0 [btrfs]
(...)
We were also not freeing the btrfs_dio_private we allocated previously,
which kmemleak reported with the following trace in its sysfs file:
unreferenced object 0xffff8803f553bf80 (size 96):
comm "xfs_io", pid 4501, jiffies 4295039588 (age 173.936s)
hex dump (first 32 bytes):
88 6c 9b f5 02 88 ff ff 00 00 00 00 00 00 00 00 .l..............
00 00 00 00 00 00 00 00 00 00 c4 00 00 00 00 00 ................
backtrace:
[<ffffffff81161ffe>] create_object+0x172/0x29a
[<ffffffff8145870f>] kmemleak_alloc+0x25/0x41
[<ffffffff81154e64>] kmemleak_alloc_recursive.constprop.40+0x16/0x18
[<ffffffff811579ed>] kmem_cache_alloc_trace+0xfb/0x148
[<ffffffffa03d8cff>] btrfs_submit_direct+0x65/0x16a [btrfs]
[<ffffffff811968dc>] dio_bio_submit+0x62/0x8f
[<ffffffff811975fe>] do_blockdev_direct_IO+0x97e/0xb43
[<ffffffff811977f5>] __blockdev_direct_IO+0x32/0x34
[<ffffffffa03d70ae>] btrfs_direct_IO+0x198/0x21f [btrfs]
[<ffffffff81112ca1>] generic_file_direct_write+0xb3/0x128
[<ffffffffa03e604d>] btrfs_file_write_iter+0x201/0x3e0 [btrfs]
[<ffffffff8116586a>] __vfs_write+0x7c/0xa5
[<ffffffff81165da9>] vfs_write+0xa0/0xe4
[<ffffffff81166675>] SyS_pwrite64+0x64/0x82
[<ffffffff81464fd7>] system_call_fastpath+0x12/0x6f
[<ffffffffffffffff>] 0xffffffffffffffff
For read requests we weren't doing any cleanup either (none of the work
done by btrfs_endio_direct_read()), so a failure submitting a bio for a
read request would leave a range in the inode's io_tree locked forever,
blocking any future operations (both reads and writes) against that range.
So fix this by making sure we do the same cleanup that we do for the case
where the bio submission succeeds.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
One issue users have reported is that dedupe changes mtime on files,
resulting in tools like rsync thinking that their contents have changed when
in fact the data is exactly the same. We also skip the ctime update as no
user-visible metadata changes here and we want dedupe to be transparent to
the user.
Clone still wants time changes, so we special case this in the code.
This was tested with the btrfs-extent-same tool.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
clone() supports cloning within an inode so extent-same can do
the same now. This patch fixes up the locking in extent-same to
know about the single-inode case. In addition to that, we add a
check for overlapping ranges, which clone does not allow.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
->readpage() does page_lock() before extent_lock(), we do the opposite in
extent-same. We want to reverse the order in btrfs_extent_same() but it's
not quite straightforward since the page locks are taken inside btrfs_cmp_data().
So I split btrfs_cmp_data() into 3 parts with a small context structure that
is passed between them. The first, btrfs_cmp_data_prepare() gathers up the
pages needed (taking page lock as required) and puts them on our context
structure. At this point, we are safe to lock the extent range. Afterwards,
we use btrfs_cmp_data() to do the data compare as usual and btrfs_cmp_data_free()
to clean up our context.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
In the case that we dedupe the tail of a file, we might expand the dedupe
len out to the end of our last block. We don't want to compare data past
i_size however, so pass the original length to btrfs_cmp_data().
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
When we have the no_holes feature enabled, if a we truncate a file to a
smaller size, truncate it again but to a size greater than or equals to
its original size and fsync it, the log tree will not have any information
about the hole covering the range [truncate_1_offset, new_file_size[.
Which means if the fsync log is replayed, the file will remain with the
state it had before both truncate operations.
Without the no_holes feature this does not happen, since when the inode
is logged (full sync flag is set) it will find in the fs/subvol tree a
leaf with a generation matching the current transaction id that has an
explicit extent item representing the hole.
Fix this by adding an explicit extent item representing a hole between
the last extent and the inode's i_size if we are doing a full sync.
The issue is easy to reproduce with the following test case for fstests:
. ./common/rc
. ./common/filter
. ./common/dmflakey
_need_to_be_root
_supported_fs generic
_supported_os Linux
_require_scratch
_require_dm_flakey
# This test was motivated by an issue found in btrfs when the btrfs
# no-holes feature is enabled (introduced in kernel 3.14). So enable
# the feature if the fs being tested is btrfs.
if [ $FSTYP == "btrfs" ]; then
_require_btrfs_fs_feature "no_holes"
_require_btrfs_mkfs_feature "no-holes"
MKFS_OPTIONS="$MKFS_OPTIONS -O no-holes"
fi
rm -f $seqres.full
_scratch_mkfs >>$seqres.full 2>&1
_init_flakey
_mount_flakey
# Create our test files and make sure everything is durably persisted.
$XFS_IO_PROG -f -c "pwrite -S 0xaa 0 64K" \
-c "pwrite -S 0xbb 64K 61K" \
$SCRATCH_MNT/foo | _filter_xfs_io
$XFS_IO_PROG -f -c "pwrite -S 0xee 0 64K" \
-c "pwrite -S 0xff 64K 61K" \
$SCRATCH_MNT/bar | _filter_xfs_io
sync
# Now truncate our file foo to a smaller size (64Kb) and then truncate
# it to the size it had before the shrinking truncate (125Kb). Then
# fsync our file. If a power failure happens after the fsync, we expect
# our file to have a size of 125Kb, with the first 64Kb of data having
# the value 0xaa and the second 61Kb of data having the value 0x00.
$XFS_IO_PROG -c "truncate 64K" \
-c "truncate 125K" \
-c "fsync" \
$SCRATCH_MNT/foo
# Do something similar to our file bar, but the first truncation sets
# the file size to 0 and the second truncation expands the size to the
# double of what it was initially.
$XFS_IO_PROG -c "truncate 0" \
-c "truncate 253K" \
-c "fsync" \
$SCRATCH_MNT/bar
_load_flakey_table $FLAKEY_DROP_WRITES
_unmount_flakey
# Allow writes again, mount to trigger log replay and validate file
# contents.
_load_flakey_table $FLAKEY_ALLOW_WRITES
_mount_flakey
# We expect foo to have a size of 125Kb, the first 64Kb of data all
# having the value 0xaa and the remaining 61Kb to be a hole (all bytes
# with value 0x00).
echo "File foo content after log replay:"
od -t x1 $SCRATCH_MNT/foo
# We expect bar to have a size of 253Kb and no extents (any byte read
# from bar has the value 0x00).
echo "File bar content after log replay:"
od -t x1 $SCRATCH_MNT/bar
status=0
exit
The expected file contents in the golden output are:
File foo content after log replay:
0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
*
0200000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0372000
File bar content after log replay:
0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0772000
Without this fix, their contents are:
File foo content after log replay:
0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
*
0200000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
*
0372000
File bar content after log replay:
0000000 ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee
*
0200000 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
*
0372000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0772000
A test case submission for fstests follows soon.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
After commit 4f764e5153 ("Btrfs: remove deleted xattrs on fsync log
replay"), we can end up in a situation where during log replay we end up
deleting xattrs that were never deleted when their file was last fsynced.
This happens in the fast fsync path (flag BTRFS_INODE_NEEDS_FULL_SYNC is
not set in the inode) if the inode has the flag BTRFS_INODE_COPY_EVERYTHING
set, the xattr was added in a past transaction and the leaf where the
xattr is located was not updated (COWed or created) in the current
transaction. In this scenario the xattr item never ends up in the log
tree and therefore at log replay time, which makes the replay code delete
the xattr from the fs/subvol tree as it thinks that xattr was deleted
prior to the last fsync.
Fix this by always logging all xattrs, which is the simplest and most
reliable way to detect deleted xattrs and replay the deletes at log replay
time.
This issue is reproducible with the following test case for fstests:
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
here=`pwd`
tmp=/tmp/$$
status=1 # failure is the default!
_cleanup()
{
_cleanup_flakey
rm -f $tmp.*
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
. ./common/dmflakey
. ./common/attr
# real QA test starts here
# We create a lot of xattrs for a single file. Only btrfs and xfs are currently
# able to store such a large mount of xattrs per file, other filesystems such
# as ext3/4 and f2fs for example, fail with ENOSPC even if we attempt to add
# less than 1000 xattrs with very small values.
_supported_fs btrfs xfs
_supported_os Linux
_need_to_be_root
_require_scratch
_require_dm_flakey
_require_attrs
_require_metadata_journaling $SCRATCH_DEV
rm -f $seqres.full
_scratch_mkfs >> $seqres.full 2>&1
_init_flakey
_mount_flakey
# Create the test file with some initial data and make sure everything is
# durably persisted.
$XFS_IO_PROG -f -c "pwrite -S 0xaa 0 32k" $SCRATCH_MNT/foo | _filter_xfs_io
sync
# Add many small xattrs to our file.
# We create such a large amount because it's needed to trigger the issue found
# in btrfs - we need to have an amount that causes the fs to have at least 3
# btree leafs with xattrs stored in them, and it must work on any leaf size
# (maximum leaf/node size is 64Kb).
num_xattrs=2000
for ((i = 1; i <= $num_xattrs; i++)); do
name="user.attr_$(printf "%04d" $i)"
$SETFATTR_PROG -n $name -v "val_$(printf "%04d" $i)" $SCRATCH_MNT/foo
done
# Sync the filesystem to force a commit of the current btrfs transaction, this
# is a necessary condition to trigger the bug on btrfs.
sync
# Now update our file's data and fsync the file.
# After a successful fsync, if the fsync log/journal is replayed we expect to
# see all the xattrs we added before with the same values (and the updated file
# data of course). Btrfs used to delete some of these xattrs when it replayed
# its fsync log/journal.
$XFS_IO_PROG -c "pwrite -S 0xbb 8K 16K" \
-c "fsync" \
$SCRATCH_MNT/foo | _filter_xfs_io
# Simulate a crash/power loss.
_load_flakey_table $FLAKEY_DROP_WRITES
_unmount_flakey
# Allow writes again and mount. This makes the fs replay its fsync log.
_load_flakey_table $FLAKEY_ALLOW_WRITES
_mount_flakey
echo "File content after crash and log replay:"
od -t x1 $SCRATCH_MNT/foo
echo "File xattrs after crash and log replay:"
for ((i = 1; i <= $num_xattrs; i++)); do
name="user.attr_$(printf "%04d" $i)"
echo -n "$name="
$GETFATTR_PROG --absolute-names -n $name --only-values $SCRATCH_MNT/foo
echo
done
status=0
exit
The golden output expects all xattrs to be available, and with the correct
values, after the fsync log is replayed.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
If we do an append write to a file (which increases its inode's i_size)
that does not have the flag BTRFS_INODE_NEEDS_FULL_SYNC set in its inode,
and the previous transaction added a new hard link to the file, which sets
the flag BTRFS_INODE_COPY_EVERYTHING in the file's inode, and then fsync
the file, the inode's new i_size isn't logged. This has the consequence
that after the fsync log is replayed, the file size remains what it was
before the append write operation, which means users/applications will
not be able to read the data that was successsfully fsync'ed before.
This happens because neither the inode item nor the delayed inode get
their i_size updated when the append write is made - doing so would
require starting a transaction in the buffered write path, something that
we do not do intentionally for performance reasons.
Fix this by making sure that when the flag BTRFS_INODE_COPY_EVERYTHING is
set the inode is logged with its current i_size (log the in-memory inode
into the log tree).
This issue is not a recent regression and is easy to reproduce with the
following test case for fstests:
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
here=`pwd`
tmp=/tmp/$$
status=1 # failure is the default!
_cleanup()
{
_cleanup_flakey
rm -f $tmp.*
}
trap "_cleanup; exit \$status" 0 1 2 3 15
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
. ./common/dmflakey
# real QA test starts here
_supported_fs generic
_supported_os Linux
_need_to_be_root
_require_scratch
_require_dm_flakey
_require_metadata_journaling $SCRATCH_DEV
_crash_and_mount()
{
# Simulate a crash/power loss.
_load_flakey_table $FLAKEY_DROP_WRITES
_unmount_flakey
# Allow writes again and mount. This makes the fs replay its fsync log.
_load_flakey_table $FLAKEY_ALLOW_WRITES
_mount_flakey
}
rm -f $seqres.full
_scratch_mkfs >> $seqres.full 2>&1
_init_flakey
_mount_flakey
# Create the test file with some initial data and then fsync it.
# The fsync here is only needed to trigger the issue in btrfs, as it causes the
# the flag BTRFS_INODE_NEEDS_FULL_SYNC to be removed from the btrfs inode.
$XFS_IO_PROG -f -c "pwrite -S 0xaa 0 32k" \
-c "fsync" \
$SCRATCH_MNT/foo | _filter_xfs_io
sync
# Add a hard link to our file.
# On btrfs this sets the flag BTRFS_INODE_COPY_EVERYTHING on the btrfs inode,
# which is a necessary condition to trigger the issue.
ln $SCRATCH_MNT/foo $SCRATCH_MNT/bar
# Sync the filesystem to force a commit of the current btrfs transaction, this
# is a necessary condition to trigger the bug on btrfs.
sync
# Now append more data to our file, increasing its size, and fsync the file.
# In btrfs because the inode flag BTRFS_INODE_COPY_EVERYTHING was set and the
# write path did not update the inode item in the btree nor the delayed inode
# item (in memory struture) in the current transaction (created by the fsync
# handler), the fsync did not record the inode's new i_size in the fsync
# log/journal. This made the data unavailable after the fsync log/journal is
# replayed.
$XFS_IO_PROG -c "pwrite -S 0xbb 32K 32K" \
-c "fsync" \
$SCRATCH_MNT/foo | _filter_xfs_io
echo "File content after fsync and before crash:"
od -t x1 $SCRATCH_MNT/foo
_crash_and_mount
echo "File content after crash and log replay:"
od -t x1 $SCRATCH_MNT/foo
status=0
exit
The expected file output before and after the crash/power failure expects the
appended data to be available, which is:
0000000 aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa aa
*
0100000 bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
*
0200000
Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
While the inode cache caching kthread is calling btrfs_unpin_free_ino(),
we could have a concurrent call to btrfs_return_ino() that adds a new
entry to the root's free space cache of pinned inodes. This concurrent
call does not acquire the fs_info->commit_root_sem before adding a new
entry if the caching state is BTRFS_CACHE_FINISHED, which is a problem
because the caching kthread calls btrfs_unpin_free_ino() after setting
the caching state to BTRFS_CACHE_FINISHED and therefore races with
the task calling btrfs_return_ino(), which is adding a new entry, while
the former (caching kthread) is navigating the cache's rbtree, removing
and freeing nodes from the cache's rbtree without acquiring the spinlock
that protects the rbtree.
This race resulted in memory corruption due to double free of struct
btrfs_free_space objects because both tasks can end up doing freeing the
same objects. Note that adding a new entry can result in merging it with
other entries in the cache, in which case those entries are freed.
This is particularly important as btrfs_free_space structures are also
used for the block group free space caches.
This memory corruption can be detected by a debugging kernel, which
reports it with the following trace:
[132408.501148] slab error in verify_redzone_free(): cache `btrfs_free_space': double free detected
[132408.505075] CPU: 15 PID: 12248 Comm: btrfs-ino-cache Tainted: G W 4.1.0-rc5-btrfs-next-10+ #1
[132408.505075] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[132408.505075] ffff880023e7d320 ffff880163d73cd8 ffffffff8145eec7 ffffffff81095dce
[132408.505075] ffff880009735d40 ffff880163d73ce8 ffffffff81154e1e ffff880163d73d68
[132408.505075] ffffffff81155733 ffffffffa054a95a ffff8801b6099f00 ffffffffa0505b5f
[132408.505075] Call Trace:
[132408.505075] [<ffffffff8145eec7>] dump_stack+0x4f/0x7b
[132408.505075] [<ffffffff81095dce>] ? console_unlock+0x356/0x3a2
[132408.505075] [<ffffffff81154e1e>] __slab_error.isra.28+0x25/0x36
[132408.505075] [<ffffffff81155733>] __cache_free+0xe2/0x4b6
[132408.505075] [<ffffffffa054a95a>] ? __btrfs_add_free_space+0x2f0/0x343 [btrfs]
[132408.505075] [<ffffffffa0505b5f>] ? btrfs_unpin_free_ino+0x8e/0x99 [btrfs]
[132408.505075] [<ffffffff810f3b30>] ? time_hardirqs_off+0x15/0x28
[132408.505075] [<ffffffff81084d42>] ? trace_hardirqs_off+0xd/0xf
[132408.505075] [<ffffffff811563a1>] ? kfree+0xb6/0x14e
[132408.505075] [<ffffffff811563d0>] kfree+0xe5/0x14e
[132408.505075] [<ffffffffa0505b5f>] btrfs_unpin_free_ino+0x8e/0x99 [btrfs]
[132408.505075] [<ffffffffa0505e08>] caching_kthread+0x29e/0x2d9 [btrfs]
[132408.505075] [<ffffffffa0505b6a>] ? btrfs_unpin_free_ino+0x99/0x99 [btrfs]
[132408.505075] [<ffffffff8106698f>] kthread+0xef/0xf7
[132408.505075] [<ffffffff810f3b08>] ? time_hardirqs_on+0x15/0x28
[132408.505075] [<ffffffff810668a0>] ? __kthread_parkme+0xad/0xad
[132408.505075] [<ffffffff814653d2>] ret_from_fork+0x42/0x70
[132408.505075] [<ffffffff810668a0>] ? __kthread_parkme+0xad/0xad
[132408.505075] ffff880023e7d320: redzone 1:0x9f911029d74e35b, redzone 2:0x9f911029d74e35b.
[132409.501654] slab: double free detected in cache 'btrfs_free_space', objp ffff880023e7d320
[132409.503355] ------------[ cut here ]------------
[132409.504241] kernel BUG at mm/slab.c:2571!
Therefore fix this by having btrfs_unpin_free_ino() acquire the lock
that protects the rbtree while doing the searches and removing entries.
Fixes: 1c70d8fb4d ("Btrfs: fix inode caching vs tree log")
Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
The free space entries are allocated using kmem_cache_zalloc(),
through __btrfs_add_free_space(), therefore we should use
kmem_cache_free() and not kfree() to avoid any confusion and
any potential problem. Looking at the kfree() definition at
mm/slab.c it has the following comment:
/*
* (...)
*
* Don't free memory not originally allocated by kmalloc()
* or you will run into trouble.
*/
So better be safe and use kmem_cache_free().
Cc: stable@vger.kernel.org
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
Although it is a rare case, we'd better free previous allocated
memory on error.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
It is introduced by:
c404e0dc2c
Btrfs: fix use-after-free in the finishing procedure of the device replace
But seems no relationship with that bug, this patch revirt these
code block for cleanup.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently, we can only set a limitation on a qgroup, but we
can not clear it.
This patch provide a choice to user to clear a limitation on
qgroup by passing a value of CLEAR_VALUE(-1) to kernel.
Reported-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com>
Tested-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
There is a cut and paste error so instead of freeing "head_ref", we free
"ref" twice.
Fixes: 3368d001ba ('btrfs: qgroup: Record possible quota-related extent for qgroup.')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
This patch will add support to show the replacing target in sysfs
during the process of replacement.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.cz>
When btrfs on a device is overwritten with a new btrfs (mkfs),
the old btrfs instance in the kernel becomes stale. So with this
patch, if kernel finds device is overwritten then delete the stale
fsid/uuid.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Neil Horman pointed out a problem where if he did something like this
receive A
snap A B
change B
send -p A B
and then on another box do
recieve A
receive B
the receive B would fail because we use the UUID of A for the clone sources for
B. This makes sense most of the time because normally you are sending from the
original sources, not a received source. However when you use a recieved subvol
its UUID is going to be something completely different, so if you then try to
receive the diff on a different volume it won't find the UUID because the new A
will be something else. The only constant is the received uuid. So instead
check to see if we have received_uuid set on the root, and if so use that as the
clone source, as btrfs receive looks for matches either in received_uuid or
uuid. Thanks,
Reported-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Hugo Mills <hugo@carfax.org.uk>
Signed-off-by: Chris Mason <clm@fb.com>
@log_root_tree should not be referenced after kfree.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs will report no_space when we run following write and delete
file loop:
# FILE_SIZE_M=[ 75% of fs space ]
# DEV=[ some dev ]
# MNT=[ some dir ]
#
# mkfs.btrfs -f "$DEV"
# mount -o nodatacow "$DEV" "$MNT"
# for ((i = 0; i < 100; i++)); do dd if=/dev/zero of="$MNT"/file0 bs=1M count="$FILE_SIZE_M"; rm -f "$MNT"/file0; done
#
Reason:
iput() and evict() is run after write pages to block device, if
write pages work is not finished before next write, the "rm"ed space
is not freed, and caused above bug.
Fix:
We can add "-o flushoncommit" mount option to avoid above bug, but
it have performance problem. Actually, we can to wait for on-the-fly
writes only when no-space happened, it is which this patch do.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
qgroup.
Make snapshot accounting work with new extent-oriented mechanism by
skipping given root in new/old_roots in create_pending_snapshot().
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This is used by later qgroup fix patches for snapshot.
As current snapshot accounting is done by btrfs_qgroup_inherit(), but
new extent oriented quota mechanism will account extent from
btrfs_copy_root() and other snapshot things, causing wrong result.
So add this ability to handle snapshot accounting.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This function will delete unode with given (val,aux) pair.
And with this patch, seqnum for debug usage doesn't have any meaning
now, so remove them.
This is used by later patches to skip snapshot root.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Since the self test transaction don't have delayed_ref_roots, so use
find_all_roots() and export btrfs_qgroup_account_extent() to simulate it
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Switch from old ref_node based qgroup to extent based qgroup mechanism
for normal operations.
The new mechanism should hugely reduce the overhead of btrfs quota
system, and further more, the codes and logic should be more clean and
easier to maintain.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Switch rescan to use the new new extent oriented mechanism.
As rescan is also based on extent, new mechanism is just a perfect match
for rescan.
With re-designed internal functions, rescan is quite easy, just call
btrfs_find_all_roots() and then btrfs_qgroup_account_one_extent().
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs_qgroup_account_extents().
The new btrfs_qgroup_account_extents() function should be called in
btrfs_commit_transaction() and it will update all the qgroup according
to delayed_ref_root->dirty_extent_root.
The new function can handle both normal operation during
commit_transaction() or in rescan in a unified method with clearer
logic.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs_find_all_roots().
Allow btrfs_find_all_roots() to skip all delayed_ref_head lock and tree
lock to do tree search.
This is important for later qgroup implement which will call
find_all_roots() after fs trees are committed.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add function btrfs_qgroup_prepare_account_extents() to get old_roots
which are needed for qgroup.
We do it in commit_transaction() and before switch_roots(), and only
search commit_root, so it gives a quite accurate view for previous
transaction.
With old_roots from previous transaction, we can use it to do accurate
account with current transaction.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add hook in add_delayed_ref_head() to record quota-related extent record
into delayed_ref_root->dirty_extent_record rb-tree for later qgroup
accounting.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Jeff Mahoney
Filipe Manana
Anand Jain
Zhao Lei
Shilong Wang
Liu Bo
Mark Fasheh
Yang Dongsheng
Dan Carpenter
Chris Mason
Josef Bacik
Qu Wenruo