Reflinking (clone/dedupe) and rename are operations that operate on two
inodes and therefore need to lock them in the same order to avoid ABBA
deadlocks. It happens that Btrfs' reflink implementation always locked
them in a different order from VFS's lock_two_nondirectories() helper,
which is used by the rename code in VFS, resulting in ABBA type deadlocks.
Btrfs' locking order:
static void btrfs_double_inode_lock(struct inode *inode1, struct inode *inode2)
{
if (inode1 < inode2)
swap(inode1, inode2);
inode_lock_nested(inode1, I_MUTEX_PARENT);
inode_lock_nested(inode2, I_MUTEX_CHILD);
}
VFS's locking order:
void lock_two_nondirectories(struct inode *inode1, struct inode *inode2)
{
if (inode1 > inode2)
swap(inode1, inode2);
if (inode1 && !S_ISDIR(inode1->i_mode))
inode_lock(inode1);
if (inode2 && !S_ISDIR(inode2->i_mode) && inode2 != inode1)
inode_lock_nested(inode2, I_MUTEX_NONDIR2);
}
Fix this by killing the btrfs helper function that does the double inode
locking and replace it with VFS's helper lock_two_nondirectories().
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Fixes: 416161db9b ("btrfs: offline dedupe")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Comparing the content of the pages in the range to deduplicate is now
done in generic_remap_checks called by the generic helper
generic_remap_file_range_prep(), which takes care of ensuring we do not
compare/deduplicate undefined data beyond a file's EOF (range from EOF
to the next block boundary). So remove these checks which are now
redundant.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Both btrfs_find_device() and find_device() does the same thing except
that the latter does not take the seed device onto account in the device
scanning context. We can merge them.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_find_device() accepts fs_info as an argument and retrieves
fs_devices from fs_info.
Instead use fs_devices, so that this function can be used in non-mount
(during device scanning) context as well.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Move the check that verifies if both inodes have checksums disabled or
both have them enabled, from the clone and deduplication functions into
the new common helper btrfs_remap_file_range_prep().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If the call to btrfs_balance() failed we would overwrite the error
returned to user space with -EFAULT if the call to copy_to_user() failed
as well. Fix that by calling copy_to_user() only if btrfs_balance()
returned success or was canceled.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If the call to btrfs_dev_replace_by_ioctl() failed we would overwrite the
error returned to user space with -EFAULT if the call to copy_to_user()
failed as well. Fix that by calling copy_to_user() only if no error
happened before or a device replace operation was canceled.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Checking if either of the inodes corresponds to a swapfile is already
performed by generic_remap_file_range_prep(), so we do not need to do
it in the btrfs clone and deduplication functions.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fixes gcc '-Wunused-but-set-variable' warning:
fs/btrfs/ioctl.c: In function 'btrfs_extent_same':
fs/btrfs/ioctl.c:3260:6: warning:
variable 'num_pages' set but not used [-Wunused-but-set-variable]
It not used any more since commit 9ee8234e6220 ("Btrfs: use
generic_remap_file_range_prep() for cloning and deduplication")
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If the call to btrfs_get_dev_stats() failed we would overwrite the error
returned to user space with -EFAULT if the call to copy_to_user() failed
as well. Fix that by calling copy_to_user() only if btrfs_get_dev_stats()
returned success.
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If the call to btrfs_scrub_progress() failed we would overwrite the error
returned to user space with -EFAULT if the call to copy_to_user() failed
as well. Fix that by calling copy_to_user() only if btrfs_scrub_progress()
returned success.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If scrub returned an error and then the copy_to_user() call did not
succeed, we would overwrite the error returned by scrub with -EFAULT.
Fix that by calling copy_to_user() only if btrfs_scrub_dev() returned
success.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The recent rework that makes btrfs' remap_file_range operation use the
generic helper generic_remap_file_range_prep() introduced a race between
relocation and reflinking (for both cloning and deduplication) the file
extents between the source and destination inodes.
This happens because we no longer lock the source range anymore, and we do
not lock it anymore because we wait for direct IO writes and writeback to
complete early on the code path right after locking the inodes, which
guarantees no other file operations interfere with the reflinking. However
there is one exception which is relocation, since it replaces the byte
number of file extents items in the fs tree after locking the range the
file extent items represent. This is a problem because after finding each
file extent to clone in the fs tree, the reflink process copies the file
extent item into a local buffer, releases the search path, inserts new
file extent items in the destination range and then increments the
reference count for the extent mentioned in the file extent item that it
previously copied to the buffer. If right after copying the file extent
item into the buffer and releasing the path the relocation process
updates the file extent item to point to the new extent, the reflink
process ends up creating a delayed reference to increment the reference
count of the old extent, for which the relocation process already created
a delayed reference to drop it. This results in failure to run delayed
references because we will attempt to increment the count of a reference
that was already dropped. This is illustrated by the following diagram:
CPU 1 CPU 2
relocation is running
btrfs_clone_files()
btrfs_clone()
--> finds extent item
in source range
point to extent
at bytenr X
--> copies it into a
local buffer
--> releases path
replace_file_extents()
--> successfully locks the
range represented by
the file extent item
--> replaces disk_bytenr
field in the file
extent item with some
other value Y
--> creates delayed reference
to increment reference
count for extent at
bytenr Y
--> creates delayed reference
to drop the extent at
bytenr X
--> starts transaction
--> creates delayed
reference to
increment extent
at bytenr X
<delayed references are run, due to a transaction
commit for example, and the transaction is aborted
with -EIO because we attempt to increment reference
count for the extent at bytenr X after we freed it>
When this race is hit the running transaction ends up getting aborted with
an -EIO error and a trace like the following is produced:
[ 4382.553858] WARNING: CPU: 2 PID: 3648 at fs/btrfs/extent-tree.c:1552 lookup_inline_extent_backref+0x4f4/0x650 [btrfs]
(...)
[ 4382.556293] CPU: 2 PID: 3648 Comm: btrfs Tainted: G W 4.20.0-rc6-btrfs-next-41 #1
[ 4382.556294] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[ 4382.556308] RIP: 0010:lookup_inline_extent_backref+0x4f4/0x650 [btrfs]
(...)
[ 4382.556310] RSP: 0018:ffffac784408f738 EFLAGS: 00010202
[ 4382.556311] RAX: 0000000000000001 RBX: ffff8980673c3a48 RCX: 0000000000000001
[ 4382.556312] RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000000
[ 4382.556312] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
[ 4382.556313] R10: 0000000000000001 R11: ffff897f40000000 R12: 0000000000001000
[ 4382.556313] R13: 00000000c224f000 R14: ffff89805de9bd40 R15: ffff8980453f4548
[ 4382.556315] FS: 00007f5e759178c0(0000) GS:ffff89807b300000(0000) knlGS:0000000000000000
[ 4382.563130] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4382.563562] CR2: 00007f2e9789fcbc CR3: 0000000120512001 CR4: 00000000003606e0
[ 4382.564005] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4382.564451] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 4382.564887] Call Trace:
[ 4382.565343] insert_inline_extent_backref+0x55/0xe0 [btrfs]
[ 4382.565796] __btrfs_inc_extent_ref.isra.60+0x88/0x260 [btrfs]
[ 4382.566249] ? __btrfs_run_delayed_refs+0x93/0x1650 [btrfs]
[ 4382.566702] __btrfs_run_delayed_refs+0xa22/0x1650 [btrfs]
[ 4382.567162] btrfs_run_delayed_refs+0x7e/0x1d0 [btrfs]
[ 4382.567623] btrfs_commit_transaction+0x50/0x9c0 [btrfs]
[ 4382.568112] ? _raw_spin_unlock+0x24/0x30
[ 4382.568557] ? block_rsv_release_bytes+0x14e/0x410 [btrfs]
[ 4382.569006] create_subvol+0x3c8/0x830 [btrfs]
[ 4382.569461] ? btrfs_mksubvol+0x317/0x600 [btrfs]
[ 4382.569906] btrfs_mksubvol+0x317/0x600 [btrfs]
[ 4382.570383] ? rcu_sync_lockdep_assert+0xe/0x60
[ 4382.570822] ? __sb_start_write+0xd4/0x1c0
[ 4382.571262] ? mnt_want_write_file+0x24/0x50
[ 4382.571712] btrfs_ioctl_snap_create_transid+0x117/0x1a0 [btrfs]
[ 4382.572155] ? _copy_from_user+0x66/0x90
[ 4382.572602] btrfs_ioctl_snap_create+0x66/0x80 [btrfs]
[ 4382.573052] btrfs_ioctl+0x7c1/0x30e0 [btrfs]
[ 4382.573502] ? mem_cgroup_commit_charge+0x8b/0x570
[ 4382.573946] ? do_raw_spin_unlock+0x49/0xc0
[ 4382.574379] ? _raw_spin_unlock+0x24/0x30
[ 4382.574803] ? __handle_mm_fault+0xf29/0x12d0
[ 4382.575215] ? do_vfs_ioctl+0xa2/0x6f0
[ 4382.575622] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[ 4382.576020] do_vfs_ioctl+0xa2/0x6f0
[ 4382.576405] ksys_ioctl+0x70/0x80
[ 4382.576776] __x64_sys_ioctl+0x16/0x20
[ 4382.577137] do_syscall_64+0x60/0x1b0
[ 4382.577488] entry_SYSCALL_64_after_hwframe+0x49/0xbe
(...)
[ 4382.578837] RSP: 002b:00007ffe04bf64c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[ 4382.579174] RAX: ffffffffffffffda RBX: 00005564136f3050 RCX: 00007f5e74724dd7
[ 4382.579505] RDX: 00007ffe04bf64d0 RSI: 000000005000940e RDI: 0000000000000003
[ 4382.579848] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000044
[ 4382.580164] R10: 0000000000000541 R11: 0000000000000202 R12: 00005564136f3010
[ 4382.580477] R13: 0000000000000003 R14: 00005564136f3035 R15: 00005564136f3050
[ 4382.580792] irq event stamp: 0
[ 4382.581106] hardirqs last enabled at (0): [<0000000000000000>] (null)
[ 4382.581441] hardirqs last disabled at (0): [<ffffffff8d085842>] copy_process.part.32+0x6e2/0x2320
[ 4382.581772] softirqs last enabled at (0): [<ffffffff8d085842>] copy_process.part.32+0x6e2/0x2320
[ 4382.582095] softirqs last disabled at (0): [<0000000000000000>] (null)
[ 4382.582413] ---[ end trace d3c188e3e9367382 ]---
[ 4382.623855] BTRFS: error (device sdc) in btrfs_run_delayed_refs:2981: errno=-5 IO failure
[ 4382.624295] BTRFS info (device sdc): forced readonly
Fix this by locking the source range before searching for the file extent
items in the fs tree, since the relocation process will try to lock the
range a file extent item represents before updating it with the new extent
location.
Fixes: 34a28e3d77 ("Btrfs: use generic_remap_file_range_prep() for cloning and deduplication")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The recent rework that makes btrfs' remap_file_range operation use the
generic helper generic_remap_file_range_prep() introduced a race between
writeback and cloning a range that covers the eof extent of the source
file into a destination offset that is greater then the same file's size.
This happens because we now wait for writeback to complete before doing
the truncation of the eof block, while previously we did the truncation
and then waited for writeback to complete. This leads to a race between
writeback of the truncated block and cloning the file extents in the
source range, because we copy each file extent item we find in the fs
root into a buffer, then release the path and then increment the reference
count for the extent referred in that file extent item we copied, which
can no longer exist if writeback of the truncated eof block completes
after we copied the file extent item into the buffer and before we
incremented the reference count. This is illustrated by the following
diagram:
CPU 1 CPU 2
btrfs_clone_files()
btrfs_cont_expand()
btrfs_truncate_block()
--> zeroes part of the
page containg eof,
marking it for
delalloc
btrfs_clone()
--> finds extent item
covering eof,
points to extent
at bytenr X
--> copies it into a
local buffer
--> releases path
writeback starts
btrfs_finish_ordered_io()
insert_reserved_file_extent()
__btrfs_drop_extents()
--> creates delayed
reference to drop
the extent at
bytenr X
--> starts transaction
--> creates delayed
reference to
increment extent
at bytenr X
<delayed references are run, due to a transaction
commit for example, and the transaction is aborted
with -EIO because we attempt to increment reference
count for the extent at bytenr X after we freed it>
When this race is hit the running transaction ends up getting aborted with
an -EIO error and a trace like the following is produced:
[ 4382.553858] WARNING: CPU: 2 PID: 3648 at fs/btrfs/extent-tree.c:1552 lookup_inline_extent_backref+0x4f4/0x650 [btrfs]
(...)
[ 4382.556293] CPU: 2 PID: 3648 Comm: btrfs Tainted: G W 4.20.0-rc6-btrfs-next-41 #1
[ 4382.556294] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[ 4382.556308] RIP: 0010:lookup_inline_extent_backref+0x4f4/0x650 [btrfs]
(...)
[ 4382.556310] RSP: 0018:ffffac784408f738 EFLAGS: 00010202
[ 4382.556311] RAX: 0000000000000001 RBX: ffff8980673c3a48 RCX: 0000000000000001
[ 4382.556312] RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000000
[ 4382.556312] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
[ 4382.556313] R10: 0000000000000001 R11: ffff897f40000000 R12: 0000000000001000
[ 4382.556313] R13: 00000000c224f000 R14: ffff89805de9bd40 R15: ffff8980453f4548
[ 4382.556315] FS: 00007f5e759178c0(0000) GS:ffff89807b300000(0000) knlGS:0000000000000000
[ 4382.563130] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 4382.563562] CR2: 00007f2e9789fcbc CR3: 0000000120512001 CR4: 00000000003606e0
[ 4382.564005] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 4382.564451] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 4382.564887] Call Trace:
[ 4382.565343] insert_inline_extent_backref+0x55/0xe0 [btrfs]
[ 4382.565796] __btrfs_inc_extent_ref.isra.60+0x88/0x260 [btrfs]
[ 4382.566249] ? __btrfs_run_delayed_refs+0x93/0x1650 [btrfs]
[ 4382.566702] __btrfs_run_delayed_refs+0xa22/0x1650 [btrfs]
[ 4382.567162] btrfs_run_delayed_refs+0x7e/0x1d0 [btrfs]
[ 4382.567623] btrfs_commit_transaction+0x50/0x9c0 [btrfs]
[ 4382.568112] ? _raw_spin_unlock+0x24/0x30
[ 4382.568557] ? block_rsv_release_bytes+0x14e/0x410 [btrfs]
[ 4382.569006] create_subvol+0x3c8/0x830 [btrfs]
[ 4382.569461] ? btrfs_mksubvol+0x317/0x600 [btrfs]
[ 4382.569906] btrfs_mksubvol+0x317/0x600 [btrfs]
[ 4382.570383] ? rcu_sync_lockdep_assert+0xe/0x60
[ 4382.570822] ? __sb_start_write+0xd4/0x1c0
[ 4382.571262] ? mnt_want_write_file+0x24/0x50
[ 4382.571712] btrfs_ioctl_snap_create_transid+0x117/0x1a0 [btrfs]
[ 4382.572155] ? _copy_from_user+0x66/0x90
[ 4382.572602] btrfs_ioctl_snap_create+0x66/0x80 [btrfs]
[ 4382.573052] btrfs_ioctl+0x7c1/0x30e0 [btrfs]
[ 4382.573502] ? mem_cgroup_commit_charge+0x8b/0x570
[ 4382.573946] ? do_raw_spin_unlock+0x49/0xc0
[ 4382.574379] ? _raw_spin_unlock+0x24/0x30
[ 4382.574803] ? __handle_mm_fault+0xf29/0x12d0
[ 4382.575215] ? do_vfs_ioctl+0xa2/0x6f0
[ 4382.575622] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[ 4382.576020] do_vfs_ioctl+0xa2/0x6f0
[ 4382.576405] ksys_ioctl+0x70/0x80
[ 4382.576776] __x64_sys_ioctl+0x16/0x20
[ 4382.577137] do_syscall_64+0x60/0x1b0
[ 4382.577488] entry_SYSCALL_64_after_hwframe+0x49/0xbe
(...)
[ 4382.578837] RSP: 002b:00007ffe04bf64c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[ 4382.579174] RAX: ffffffffffffffda RBX: 00005564136f3050 RCX: 00007f5e74724dd7
[ 4382.579505] RDX: 00007ffe04bf64d0 RSI: 000000005000940e RDI: 0000000000000003
[ 4382.579848] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000044
[ 4382.580164] R10: 0000000000000541 R11: 0000000000000202 R12: 00005564136f3010
[ 4382.580477] R13: 0000000000000003 R14: 00005564136f3035 R15: 00005564136f3050
[ 4382.580792] irq event stamp: 0
[ 4382.581106] hardirqs last enabled at (0): [<0000000000000000>] (null)
[ 4382.581441] hardirqs last disabled at (0): [<ffffffff8d085842>] copy_process.part.32+0x6e2/0x2320
[ 4382.581772] softirqs last enabled at (0): [<ffffffff8d085842>] copy_process.part.32+0x6e2/0x2320
[ 4382.582095] softirqs last disabled at (0): [<0000000000000000>] (null)
[ 4382.582413] ---[ end trace d3c188e3e9367382 ]---
[ 4382.623855] BTRFS: error (device sdc) in btrfs_run_delayed_refs:2981: errno=-5 IO failure
[ 4382.624295] BTRFS info (device sdc): forced readonly
Fix this by waiting for writeback to complete after truncating the eof
block.
Fixes: 34a28e3d77 ("Btrfs: use generic_remap_file_range_prep() for cloning and deduplication")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since cloning and deduplication are no longer Btrfs specific operations, we
now have generic code to handle parameter validation, compare file ranges
used for deduplication, clear capabilities when cloning, etc. This change
makes Btrfs use it, eliminating a lot of code in Btrfs and also fixing a
few bugs, such as:
1) When cloning, the destination file's capabilities were not dropped
(the fstest generic/513 tests this);
2) We were not checking if the destination file is immutable;
3) Not checking if either the source or destination files are swap
files (swap file support is coming soon for Btrfs);
4) System limits were not checked (resource limits and O_LARGEFILE).
Note that the generic helper generic_remap_file_range_prep() does start
and waits for writeback by calling filemap_write_and_wait_range(), however
that is not enough for Btrfs for two reasons:
1) With compression, we need to start writeback twice in order to get the
pages marked for writeback and ordered extents created;
2) filemap_write_and_wait_range() (and all its other variants) only waits
for the IO to complete, but we need to wait for the ordered extents to
finish, so that when we do the actual reflinking operations the file
extent items are in the fs tree. This is also important due to the fact
that the generic helper, for the deduplication case, compares the
contents of the pages in the requested range, which might require
reading extents from disk in the very unlikely case that pages get
invalidated after writeback finishes (so the file extent items must be
up to date in the fs tree).
Since these reasons are specific to Btrfs we have to do it in the Btrfs
code before calling generic_remap_file_range_prep(). This also results
in a simpler way of dealing with existing delalloc in the source/target
ranges, specially for the deduplication case where we used to lock all
the pages first and then if we found any dealloc for the range, or
ordered extent, we would unlock the pages trigger writeback and wait for
ordered extents to complete, then lock all the pages again and check if
deduplication can be done. So now we get a simpler approach: lock the
inodes, then trigger writeback and then wait for ordered extents to
complete.
So make btrfs use generic_remap_file_range_prep() (XFS and OCFS2 use it)
to eliminate duplicated code, fix a few bugs and benefit from future bug
fixes done there - for example the recent clone and dedupe bugs involving
reflinking a partial EOF block got a counterpart fix in the generic
helper, since it affected all filesystems supporting these operations,
so we no longer need special checks in Btrfs for them.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_fs_info structure contains a copy of the
fsid/metadata_uuid fields. Same values are also contained in the
btrfs_fs_devices structure which fs_info has a reference to. Let's
reduce duplication by removing the fields from fs_info and always refer
to the ones in fs_devices. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Snapshot is expected to be fast. But if there are writers steadily
creating dirty pages in our subvolume, the snapshot may take a very long
time to complete. To fix the problem, we use tagged writepage for
snapshot flusher as we do in the generic write_cache_pages(), so we can
omit pages dirtied after the snapshot command.
This does not change the semantics regarding which data get to the
snapshot, if there are pages being dirtied during the snapshotting
operation. There's a sync called before snapshot is taken in old/new
case, any IO in flight just after that may be in the snapshot but this
depends on other system effects that might still sync the IO.
We do a simple snapshot speed test on a Intel D-1531 box:
fio --ioengine=libaio --iodepth=32 --bs=4k --rw=write --size=64G
--direct=0 --thread=1 --numjobs=1 --time_based --runtime=120
--filename=/mnt/sub/testfile --name=job1 --group_reporting & sleep 5;
time btrfs sub snap -r /mnt/sub /mnt/snap; killall fio
original: 1m58sec
patched: 6.54sec
This is the best case for this patch since for a sequential write case,
we omit nearly all pages dirtied after the snapshot command.
For a multi writers, random write test:
fio --ioengine=libaio --iodepth=32 --bs=4k --rw=randwrite --size=64G
--direct=0 --thread=1 --numjobs=4 --time_based --runtime=120
--filename=/mnt/sub/testfile --name=job1 --group_reporting & sleep 5;
time btrfs sub snap -r /mnt/sub /mnt/snap; killall fio
original: 15.83sec
patched: 10.35sec
The improvement is smaller compared to the sequential write case,
since we omit only half of the pages dirtied after snapshot command.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Ethan Lien <ethanlien@synology.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A later patch will implement swap file support for Btrfs, but before we
do that, we need to make sure that the various Btrfs ioctls cannot
change a swap file.
When a swap file is active, we must make sure that the extents of the
file are not moved and that they don't become shared. That means that
the following are not safe:
- chattr +c (enable compression)
- reflink
- dedupe
- snapshot
- defrag
Don't allow those to happen on an active swap file.
Additionally, balance, resize, device remove, and device replace are
also unsafe if they affect an active swapfile. Add a red-black tree of
block groups and devices which contain an active swapfile. Relocation
checks each block group against this tree and skips it or errors out for
balance or resize, respectively. Device remove and device replace check
the tree for the device they will operate on.
Note that we don't have to worry about chattr -C (disable nocow), which
we ignore for non-empty files, because an active swapfile must be
non-empty and can't be truncated. We also don't have to worry about
autodefrag because it's only done on COW files. Truncate and fallocate
are already taken care of by the generic code. Device add doesn't do
relocation so it's not an issue, either.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-----BEGIN PGP SIGNATURE-----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=K14u
-----END PGP SIGNATURE-----
Merge tag 'for-4.20-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"Several fixes to recent release (4.19, fixes tagged for stable) and
other fixes"
* tag 'for-4.20-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
Btrfs: fix missing delayed iputs on unmount
Btrfs: fix data corruption due to cloning of eof block
Btrfs: fix infinite loop on inode eviction after deduplication of eof block
Btrfs: fix deadlock on tree root leaf when finding free extent
btrfs: avoid link error with CONFIG_NO_AUTO_INLINE
btrfs: tree-checker: Fix misleading group system information
Btrfs: fix missing data checksums after a ranged fsync (msync)
btrfs: fix pinned underflow after transaction aborted
Btrfs: fix cur_offset in the error case for nocow
We currently allow cloning a range from a file which includes the last
block of the file even if the file's size is not aligned to the block
size. This is fine and useful when the destination file has the same size,
but when it does not and the range ends somewhere in the middle of the
destination file, it leads to corruption because the bytes between the EOF
and the end of the block have undefined data (when there is support for
discard/trimming they have a value of 0x00).
Example:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ export foo_size=$((256 * 1024 + 100))
$ xfs_io -f -c "pwrite -S 0x3c 0 $foo_size" /mnt/foo
$ xfs_io -f -c "pwrite -S 0xb5 0 1M" /mnt/bar
$ xfs_io -c "reflink /mnt/foo 0 512K $foo_size" /mnt/bar
$ od -A d -t x1 /mnt/bar
0000000 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5
*
0524288 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c 3c
*
0786528 3c 3c 3c 3c 00 00 00 00 00 00 00 00 00 00 00 00
0786544 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
0790528 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5 b5
*
1048576
The bytes in the range from 786532 (512Kb + 256Kb + 100 bytes) to 790527
(512Kb + 256Kb + 4Kb - 1) got corrupted, having now a value of 0x00 instead
of 0xb5.
This is similar to the problem we had for deduplication that got recently
fixed by commit de02b9f6bb ("Btrfs: fix data corruption when
deduplicating between different files").
Fix this by not allowing such operations to be performed and return the
errno -EINVAL to user space. This is what XFS is doing as well at the VFS
level. This change however now makes us return -EINVAL instead of
-EOPNOTSUPP for cases where the source range maps to an inline extent and
the destination range's end is smaller then the destination file's size,
since the detection of inline extents is done during the actual process of
dropping file extent items (at __btrfs_drop_extents()). Returning the
-EINVAL error is done early on and solely based on the input parameters
(offsets and length) and destination file's size. This makes us consistent
with XFS and anyone else supporting cloning since this case is now checked
at a higher level in the VFS and is where the -EINVAL will be returned
from starting with kernel 4.20 (the VFS changed was introduced in 4.20-rc1
by commit 07d19dc9fb ("vfs: avoid problematic remapping requests into
partial EOF block"). So this change is more geared towards stable kernels,
as it's unlikely the new VFS checks get removed intentionally.
A test case for fstests follows soon, as well as an update to filter
existing tests that expect -EOPNOTSUPP to accept -EINVAL as well.
CC: <stable@vger.kernel.org> # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Rework the vfs_clone_file_range and vfs_dedupe_file_range infrastructure to use
a common .remap_file_range method and supply generic bounds and sanity checking
functions that are shared with the data write path. The current VFS
infrastructure has problems with rlimit, LFS file sizes, file time stamps,
maximum filesystem file sizes, stripping setuid bits, etc and so they are
addressed in these commits.
We also introduce the ability for the ->remap_file_range methods to return short
clones so that clones for vfs_copy_file_range() don't get rejected if the entire
range can't be cloned. It also allows filesystems to sliently skip deduplication
of partial EOF blocks if they are not capable of doing so without requiring
errors to be thrown to userspace.
All existing filesystems are converted to user the new .remap_file_range method,
and both XFS and ocfs2 are modified to make use of the new generic checking
infrastructure.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1
iQIcBAABAgAGBQJb29gEAAoJEK3oKUf0dfodpOAQAL2VbHjvKXEwNMDTKscSRMmZ
Z0xXo3gamFKQ+VGOqy2g2lmAYQs9SAnTuCGTJ7zIAp7u+q8gzUy5FzKAwLS4Id6L
8siaY6nzlicfO04d0MdXnWz0f3xykChgzfdQfVUlUi7WrDioBUECLPmx4a+USsp1
DQGjLOZfoOAmn2rijdnH9RTEaHqg+8mcTaLN9TRav4gGqrWxldFKXw2y6ouFC7uo
/hxTRNXR9VI+EdbDelwBNXl9nU9gQA0WLOvRKwgUrtv6bSJohTPsmXt7EbBtNcVR
cl3zDNc1sLD1bLaRLEUAszI/33wXaaQgom1iB51obIcHHef+JxRNG/j6rUMfzxZI
VaauGv5EIvtaKN0LTAqVVLQ8t2MQFYfOr8TykmO+1UFog204aKRANdVMHDSjxD/0
dTGKJGcq+HnKQ+JHDbTdvuXEL8sUUl1FiLjOQbZPw63XmuddLKFUA2TOjXn6htbU
1h1MG5d9KjGLpabp2BQheczD08NuSmcrOBNt7IoeI3+nxr3HpMwprfB9TyaERy9X
iEgyVXmjjc9bLLRW7A2wm77aW64NvPs51wKMnvuNgNwnCewrGS6cB8WVj2zbQjH1
h3f3nku44s9ctNPSBzb/sJLnpqmZQ5t0oSmrMSN+5+En6rNTacoJCzxHRJBA7z/h
Z+C6y1GTZw0euY6Zjiwu
=CE/A
-----END PGP SIGNATURE-----
Merge tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull vfs dedup fixes from Dave Chinner:
"This reworks the vfs data cloning infrastructure.
We discovered many issues with these interfaces late in the 4.19 cycle
- the worst of them (data corruption, setuid stripping) were fixed for
XFS in 4.19-rc8, but a larger rework of the infrastructure fixing all
the problems was needed. That rework is the contents of this pull
request.
Rework the vfs_clone_file_range and vfs_dedupe_file_range
infrastructure to use a common .remap_file_range method and supply
generic bounds and sanity checking functions that are shared with the
data write path. The current VFS infrastructure has problems with
rlimit, LFS file sizes, file time stamps, maximum filesystem file
sizes, stripping setuid bits, etc and so they are addressed in these
commits.
We also introduce the ability for the ->remap_file_range methods to
return short clones so that clones for vfs_copy_file_range() don't get
rejected if the entire range can't be cloned. It also allows
filesystems to sliently skip deduplication of partial EOF blocks if
they are not capable of doing so without requiring errors to be thrown
to userspace.
Existing filesystems are converted to user the new remap_file_range
method, and both XFS and ocfs2 are modified to make use of the new
generic checking infrastructure"
* tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (28 commits)
xfs: remove [cm]time update from reflink calls
xfs: remove xfs_reflink_remap_range
xfs: remove redundant remap partial EOF block checks
xfs: support returning partial reflink results
xfs: clean up xfs_reflink_remap_blocks call site
xfs: fix pagecache truncation prior to reflink
ocfs2: remove ocfs2_reflink_remap_range
ocfs2: support partial clone range and dedupe range
ocfs2: fix pagecache truncation prior to reflink
ocfs2: truncate page cache for clone destination file before remapping
vfs: clean up generic_remap_file_range_prep return value
vfs: hide file range comparison function
vfs: enable remap callers that can handle short operations
vfs: plumb remap flags through the vfs dedupe functions
vfs: plumb remap flags through the vfs clone functions
vfs: make remap_file_range functions take and return bytes completed
vfs: remap helper should update destination inode metadata
vfs: pass remap flags to generic_remap_checks
vfs: pass remap flags to generic_remap_file_range_prep
vfs: combine the clone and dedupe into a single remap_file_range
...
Change the remap_file_range functions to take a number of bytes to
operate upon and return the number of bytes they operated on. This is a
requirement for allowing fs implementations to return short clone/dedupe
results to the user, which will enable us to obey resource limits in a
graceful manner.
A subsequent patch will enable copy_file_range to signal to the
->clone_file_range implementation that it can handle a short length,
which will be returned in the function's return value. For now the
short return is not implemented anywhere so the behavior won't change --
either copy_file_range manages to clone the entire range or it tries an
alternative.
Neither clone ioctl can take advantage of this, alas.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Combine the clone_file_range and dedupe_file_range operations into a
single remap_file_range file operation dispatch since they're
fundamentally the same operation. The differences between the two can
be made in the prep functions.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
[BUG]
fstrim on some btrfs only trims the unallocated space, not trimming any
space in existing block groups.
[CAUSE]
Before fstrim_range passed to btrfs_trim_fs(), it gets truncated to
range [0, super->total_bytes). So later btrfs_trim_fs() will only be
able to trim block groups in range [0, super->total_bytes).
While for btrfs, any bytenr aligned to sectorsize is valid, since btrfs
uses its logical address space, there is nothing limiting the location
where we put block groups.
For filesystem with frequent balance, it's quite easy to relocate all
block groups and bytenr of block groups will start beyond
super->total_bytes.
In that case, btrfs will not trim existing block groups.
[FIX]
Just remove the truncation in btrfs_ioctl_fitrim(), so btrfs_trim_fs()
can get the unmodified range, which is normally set to [0, U64_MAX].
Reported-by: Chris Murphy <lists@colorremedies.com>
Fixes: f4c697e640 ("btrfs: return EINVAL if start > total_bytes in fitrim ioctl")
CC: <stable@vger.kernel.org> # v4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Since commit 8b62f87bad ("Btrfs: rework outstanding_extents"),
manual operations of outstanding_extent in btrfs_inode are replaced by
btrfs_mod_outstanding_extents().
The one in cluster_pages_for_defrag seems to be lost, so replace it
of btrfs_mod_outstanding_extents().
Fixes: 8b62f87bad ("Btrfs: rework outstanding_extents")
Signed-off-by: Su Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are two members in struct btrfs_root which indicate root's
objectid: objectid and root_key.objectid.
They are both set to the same value in __setup_root():
static void __setup_root(struct btrfs_root *root,
struct btrfs_fs_info *fs_info,
u64 objectid)
{
...
root->objectid = objectid;
...
root->root_key.objectid = objecitd;
...
}
and not changed to other value after initialization.
grep in btrfs directory shows both are used in many places:
$ grep -rI "root->root_key.objectid" | wc -l
133
$ grep -rI "root->objectid" | wc -l
55
(4.17, inc. some noise)
It is confusing to have two similar variable names and it seems
that there is no rule about which should be used in a certain case.
Since ->root_key itself is needed for tree reloc tree, let's remove
'objecitd' member and unify code to use ->root_key.objectid in all places.
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All callers pass the root tree of dir, we can push that down to the
function itself.
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-----BEGIN PGP SIGNATURE-----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=fu93
-----END PGP SIGNATURE-----
Merge tag 'for-4.19-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix for improper fsync after hardlink
- fix for a corruption during file deduplication
- use after free fixes
- RCU warning fix
- fix for buffered write to nodatacow file
* tag 'for-4.19-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: Fix suspicious RCU usage warning in btrfs_debug_in_rcu
btrfs: use after free in btrfs_quota_enable
btrfs: btrfs_shrink_device should call commit transaction at the end
btrfs: fix qgroup_free wrong num_bytes in btrfs_subvolume_reserve_metadata
Btrfs: fix data corruption when deduplicating between different files
Btrfs: sync log after logging new name
Btrfs: fix unexpected failure of nocow buffered writes after snapshotting when low on space
If we deduplicate extents between two different files we can end up
corrupting data if the source range ends at the size of the source file,
the source file's size is not aligned to the filesystem's block size
and the destination range does not go past the size of the destination
file size.
Example:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ xfs_io -f -c "pwrite -S 0x6b 0 2518890" /mnt/foo
# The first byte with a value of 0xae starts at an offset (2518890)
# which is not a multiple of the sector size.
$ xfs_io -c "pwrite -S 0xae 2518890 102398" /mnt/foo
# Confirm the file content is full of bytes with values 0x6b and 0xae.
$ od -t x1 /mnt/foo
0000000 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
*
11467540 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b ae ae ae ae ae ae
11467560 ae ae ae ae ae ae ae ae ae ae ae ae ae ae ae ae
*
11777540 ae ae ae ae ae ae ae ae
11777550
# Create a second file with a length not aligned to the sector size,
# whose bytes all have the value 0x6b, so that its extent(s) can be
# deduplicated with the first file.
$ xfs_io -f -c "pwrite -S 0x6b 0 557771" /mnt/bar
# Now deduplicate the entire second file into a range of the first file
# that also has all bytes with the value 0x6b. The destination range's
# end offset must not be aligned to the sector size and must be less
# then the offset of the first byte with the value 0xae (byte at offset
# 2518890).
$ xfs_io -c "dedupe /mnt/bar 0 1957888 557771" /mnt/foo
# The bytes in the range starting at offset 2515659 (end of the
# deduplication range) and ending at offset 2519040 (start offset
# rounded up to the block size) must all have the value 0xae (and not
# replaced with 0x00 values). In other words, we should have exactly
# the same data we had before we asked for deduplication.
$ od -t x1 /mnt/foo
0000000 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
*
11467540 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b ae ae ae ae ae ae
11467560 ae ae ae ae ae ae ae ae ae ae ae ae ae ae ae ae
*
11777540 ae ae ae ae ae ae ae ae
11777550
# Unmount the filesystem and mount it again. This guarantees any file
# data in the page cache is dropped.
$ umount /dev/sdb
$ mount /dev/sdb /mnt
$ od -t x1 /mnt/foo
0000000 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b
*
11461300 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 00 00 00 00 00
11461320 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
*
11470000 ae ae ae ae ae ae ae ae ae ae ae ae ae ae ae ae
*
11777540 ae ae ae ae ae ae ae ae
11777550
# The bytes in range 2515659 to 2519040 have a value of 0x00 and not a
# value of 0xae, data corruption happened due to the deduplication
# operation.
So fix this by rounding down, to the sector size, the length used for the
deduplication when the following conditions are met:
1) Source file's range ends at its i_size;
2) Source file's i_size is not aligned to the sector size;
3) Destination range does not cross the i_size of the destination file.
Fixes: e1d227a42e ("btrfs: Handle unaligned length in extent_same")
CC: stable@vger.kernel.org # 4.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This contains two new features:
1) Stack file operations: this allows removal of several hacks from the
VFS, proper interaction of read-only open files with copy-up,
possibility to implement fs modifying ioctls properly, and others.
2) Metadata only copy-up: when file is on lower layer and only metadata is
modified (except size) then only copy up the metadata and continue to
use the data from the lower file.
-----BEGIN PGP SIGNATURE-----
iHUEABYIAB0WIQSQHSd0lITzzeNWNm3h3BK/laaZPAUCW3srhAAKCRDh3BK/laaZ
PC6tAQCP+KklcN+TvNp502f+O/kATahSpgnun4NY1/p4I8JV+AEAzdlkTN3+MiAO
fn9brN6mBK7h59DO3hqedPLJy2vrgwg=
=QDXH
-----END PGP SIGNATURE-----
Merge tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
"This contains two new features:
- Stack file operations: this allows removal of several hacks from
the VFS, proper interaction of read-only open files with copy-up,
possibility to implement fs modifying ioctls properly, and others.
- Metadata only copy-up: when file is on lower layer and only
metadata is modified (except size) then only copy up the metadata
and continue to use the data from the lower file"
* tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (66 commits)
ovl: Enable metadata only feature
ovl: Do not do metacopy only for ioctl modifying file attr
ovl: Do not do metadata only copy-up for truncate operation
ovl: add helper to force data copy-up
ovl: Check redirect on index as well
ovl: Set redirect on upper inode when it is linked
ovl: Set redirect on metacopy files upon rename
ovl: Do not set dentry type ORIGIN for broken hardlinks
ovl: Add an inode flag OVL_CONST_INO
ovl: Treat metacopy dentries as type OVL_PATH_MERGE
ovl: Check redirects for metacopy files
ovl: Move some dir related ovl_lookup_single() code in else block
ovl: Do not expose metacopy only dentry from d_real()
ovl: Open file with data except for the case of fsync
ovl: Add helper ovl_inode_realdata()
ovl: Store lower data inode in ovl_inode
ovl: Fix ovl_getattr() to get number of blocks from lower
ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry
ovl: Copy up meta inode data from lowest data inode
ovl: Modify ovl_lookup() and friends to lookup metacopy dentry
...
Commit e9894fd3e3 ("Btrfs: fix snapshot vs nocow writting") forced
nocow writes to fallback to COW, during writeback, when a snapshot is
created. This resulted in writes made before creating the snapshot to
unexpectedly fail with ENOSPC during writeback when success (0) was
returned to user space through the write system call.
The steps leading to this problem are:
1. When it's not possible to allocate data space for a write, the
buffered write path checks if a NOCOW write is possible. If it is,
it will not reserve space and success (0) is returned to user space.
2. Then when a snapshot is created, the root's will_be_snapshotted
atomic is incremented and writeback is triggered for all inode's that
belong to the root being snapshotted. Incrementing that atomic forces
all previous writes to fallback to COW during writeback (running
delalloc).
3. This results in the writeback for the inodes to fail and therefore
setting the ENOSPC error in their mappings, so that a subsequent
fsync on them will report the error to user space. So it's not a
completely silent data loss (since fsync will report ENOSPC) but it's
a very unexpected and undesirable behaviour, because if a clean
shutdown/unmount of the filesystem happens without previous calls to
fsync, it is expected to have the data present in the files after
mounting the filesystem again.
So fix this by adding a new atomic named snapshot_force_cow to the
root structure which prevents this behaviour and works the following way:
1. It is incremented when we start to create a snapshot after triggering
writeback and before waiting for writeback to finish.
2. This new atomic is now what is used by writeback (running delalloc)
to decide whether we need to fallback to COW or not. Because we
incremented this new atomic after triggering writeback in the
snapshot creation ioctl, we ensure that all buffered writes that
happened before snapshot creation will succeed and not fallback to
COW (which would make them fail with ENOSPC).
3. The existing atomic, will_be_snapshotted, is kept because it is used
to force new buffered writes, that start after we started
snapshotting, to reserve data space even when NOCOW is possible.
This makes these writes fail early with ENOSPC when there's no
available space to allocate, preventing the unexpected behaviour of
writeback later failing with ENOSPC due to a fallback to COW mode.
Fixes: e9894fd3e3 ("Btrfs: fix snapshot vs nocow writting")
Signed-off-by: Robbie Ko <robbieko@synology.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It can be referenced from the passed transaction handle.
Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Requiring a read-write descriptor conflicts both ways with exec,
returning ETXTBSY whenever you try to defrag a program that's currently
being run, or causing intermittent exec failures on a live system being
defragged.
As defrag doesn't change the file's contents in any way, there's no
reason to consider it a rw operation. Thus, let's check only whether
the file could have been opened rw. Such access control is still needed
as currently defrag can use extra disk space, and might trigger bugs.
We return EINVAL when the request is invalid; here it's ok but merely
the user has insufficient privileges. Thus, the EPERM return value
reflects the error better -- as discussed in the identical case for
dedupe.
According to codesearch.debian.net, no userspace program distinguishes
these values beyond strerror().
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: David Sterba <dsterba@suse.com>
[ fold the EPERM patch from Adam ]
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 5d23515be6 ("btrfs: Move qgroup rescan on quota enable to
btrfs_quota_enable") not only resulted in an easier to follow code but
it also introduced a subtle bug. It changed the timing when the initial
transaction rescan was happening:
- before the commit: it would happen after transaction commit had occured
- after the commit: it might happen before the transaction was committed
This results in failure to correctly rescan the quota since there could
be data which is still not committed on disk.
This patch aims to fix this by moving the transaction creation/commit
inside btrfs_quota_enable, which allows to schedule the quota commit
after the transaction has been committed.
Fixes: 5d23515be6 ("btrfs: Move qgroup rescan on quota enable to btrfs_quota_enable")
Reported-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Link: https://marc.info/?l=linux-btrfs&m=152999289017582
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When a new extent buffer is allocated there are a few mandatory fields
which need to be set in order for the buffer to be sane: level,
generation, bytenr, backref_rev, owner and FSID/UUID. Currently this
is open coded in the callers of btrfs_alloc_tree_block, meaning it's
fairly high in the abstraction hierarchy of operations. This patch
solves this by simply moving this init code in btrfs_init_new_buffer,
since this is the function which initializes a newly allocated
extent buffer. No functional changes.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch avoids that building the BTRFS source code with smatch
triggers complaints about inconsistent indenting.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_cmp_data_free() puts cmp's src_pages and dst_pages, but leaves
their page address intact. Now, if you hit "goto again" in
btrfs_extent_same_range() and hit some error in
btrfs_cmp_data_prepare(), you'll try to unlock/put already put pages.
This is simple fix to reset the address to avoid use-after-free.
Fixes: 67b07bd4be ("Btrfs: reuse cmp workspace in EXTENT_SAME ioctl")
Signed-off-by: Naohiro Aota <naota@elisp.net>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Clean up f_op->dedupe_file_range() interface.
1) Use loff_t for offsets and length instead of u64
2) Order the arguments the same way as {copy|clone}_file_range().
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Filipe Manana