commit 13fc1d271a upstream.
There is a race between setting up a qgroup rescan worker and completing
a qgroup rescan worker that can lead to callers of the qgroup rescan wait
ioctl to either not wait for the rescan worker to complete or to hang
forever due to missing wake ups. The following diagram shows a sequence
of steps that illustrates the race.
CPU 1 CPU 2 CPU 3
btrfs_ioctl_quota_rescan()
btrfs_qgroup_rescan()
qgroup_rescan_init()
mutex_lock(&fs_info->qgroup_rescan_lock)
spin_lock(&fs_info->qgroup_lock)
fs_info->qgroup_flags |=
BTRFS_QGROUP_STATUS_FLAG_RESCAN
init_completion(
&fs_info->qgroup_rescan_completion)
fs_info->qgroup_rescan_running = true
mutex_unlock(&fs_info->qgroup_rescan_lock)
spin_unlock(&fs_info->qgroup_lock)
btrfs_init_work()
--> starts the worker
btrfs_qgroup_rescan_worker()
mutex_lock(&fs_info->qgroup_rescan_lock)
fs_info->qgroup_flags &=
~BTRFS_QGROUP_STATUS_FLAG_RESCAN
mutex_unlock(&fs_info->qgroup_rescan_lock)
starts transaction, updates qgroup status
item, etc
btrfs_ioctl_quota_rescan()
btrfs_qgroup_rescan()
qgroup_rescan_init()
mutex_lock(&fs_info->qgroup_rescan_lock)
spin_lock(&fs_info->qgroup_lock)
fs_info->qgroup_flags |=
BTRFS_QGROUP_STATUS_FLAG_RESCAN
init_completion(
&fs_info->qgroup_rescan_completion)
fs_info->qgroup_rescan_running = true
mutex_unlock(&fs_info->qgroup_rescan_lock)
spin_unlock(&fs_info->qgroup_lock)
btrfs_init_work()
--> starts another worker
mutex_lock(&fs_info->qgroup_rescan_lock)
fs_info->qgroup_rescan_running = false
mutex_unlock(&fs_info->qgroup_rescan_lock)
complete_all(&fs_info->qgroup_rescan_completion)
Before the rescan worker started by the task at CPU 3 completes, if
another task calls btrfs_ioctl_quota_rescan(), it will get -EINPROGRESS
because the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN is set at
fs_info->qgroup_flags, which is expected and correct behaviour.
However if other task calls btrfs_ioctl_quota_rescan_wait() before the
rescan worker started by the task at CPU 3 completes, it will return
immediately without waiting for the new rescan worker to complete,
because fs_info->qgroup_rescan_running is set to false by CPU 2.
This race is making test case btrfs/171 (from fstests) to fail often:
btrfs/171 9s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad)
# --- tests/btrfs/171.out 2018-09-16 21:30:48.505104287 +0100
# +++ /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad 2019-09-19 02:01:36.938486039 +0100
# @@ -1,2 +1,3 @@
# QA output created by 171
# +ERROR: quota rescan failed: Operation now in progress
# Silence is golden
# ...
# (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/171.out /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad' to see the entire diff)
That is because the test calls the btrfs-progs commands "qgroup quota
rescan -w", "qgroup assign" and "qgroup remove" in a sequence that makes
calls to the rescan start ioctl fail with -EINPROGRESS (note the "btrfs"
commands 'qgroup assign' and 'qgroup remove' often call the rescan start
ioctl after calling the qgroup assign ioctl,
btrfs_ioctl_qgroup_assign()), since previous waits didn't actually wait
for a rescan worker to complete.
Another problem the race can cause is missing wake ups for waiters,
since the call to complete_all() happens outside a critical section and
after clearing the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN. In the sequence
diagram above, if we have a waiter for the first rescan task (executed
by CPU 2), then fs_info->qgroup_rescan_completion.wait is not empty, and
if after the rescan worker clears BTRFS_QGROUP_STATUS_FLAG_RESCAN and
before it calls complete_all() against
fs_info->qgroup_rescan_completion, the task at CPU 3 calls
init_completion() against fs_info->qgroup_rescan_completion which
re-initilizes its wait queue to an empty queue, therefore causing the
rescan worker at CPU 2 to call complete_all() against an empty queue,
never waking up the task waiting for that rescan worker.
Fix this by clearing BTRFS_QGROUP_STATUS_FLAG_RESCAN and setting
fs_info->qgroup_rescan_running to false in the same critical section,
delimited by the mutex fs_info->qgroup_rescan_lock, as well as doing the
call to complete_all() in that same critical section. This gives the
protection needed to avoid rescan wait ioctl callers not waiting for a
running rescan worker and the lost wake ups problem, since setting that
rescan flag and boolean as well as initializing the wait queue is done
already in a critical section delimited by that mutex (at
qgroup_rescan_init()).
Fixes: 57254b6ebc ("Btrfs: add ioctl to wait for qgroup rescan completion")
Fixes: d2c609b834 ("btrfs: properly track when rescan worker is running")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d4e204948f upstream.
[BUG]
The following script can cause btrfs qgroup data space leak:
mkfs.btrfs -f $dev
mount $dev -o nospace_cache $mnt
btrfs subv create $mnt/subv
btrfs quota en $mnt
btrfs quota rescan -w $mnt
btrfs qgroup limit 128m $mnt/subv
for (( i = 0; i < 3; i++)); do
# Create 3 64M holes for latter fallocate to fail
truncate -s 192m $mnt/subv/file
xfs_io -c "pwrite 64m 4k" $mnt/subv/file > /dev/null
xfs_io -c "pwrite 128m 4k" $mnt/subv/file > /dev/null
sync
# it's supposed to fail, and each failure will leak at least 64M
# data space
xfs_io -f -c "falloc 0 192m" $mnt/subv/file &> /dev/null
rm $mnt/subv/file
sync
done
# Shouldn't fail after we removed the file
xfs_io -f -c "falloc 0 64m" $mnt/subv/file
[CAUSE]
Btrfs qgroup data reserve code allow multiple reservations to happen on
a single extent_changeset:
E.g:
btrfs_qgroup_reserve_data(inode, &data_reserved, 0, SZ_1M);
btrfs_qgroup_reserve_data(inode, &data_reserved, SZ_1M, SZ_2M);
btrfs_qgroup_reserve_data(inode, &data_reserved, 0, SZ_4M);
Btrfs qgroup code has its internal tracking to make sure we don't
double-reserve in above example.
The only pattern utilizing this feature is in the main while loop of
btrfs_fallocate() function.
However btrfs_qgroup_reserve_data()'s error handling has a bug in that
on error it clears all ranges in the io_tree with EXTENT_QGROUP_RESERVED
flag but doesn't free previously reserved bytes.
This bug has a two fold effect:
- Clearing EXTENT_QGROUP_RESERVED ranges
This is the correct behavior, but it prevents
btrfs_qgroup_check_reserved_leak() to catch the leakage as the
detector is purely EXTENT_QGROUP_RESERVED flag based.
- Leak the previously reserved data bytes.
The bug manifests when N calls to btrfs_qgroup_reserve_data are made and
the last one fails, leaking space reserved in the previous ones.
[FIX]
Also free previously reserved data bytes when btrfs_qgroup_reserve_data
fails.
Fixes: 5247255370 ("btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bab32fc069 upstream.
[BUG]
Under the following case with qgroup enabled, if some error happened
after we have reserved delalloc space, then in error handling path, we
could cause qgroup data space leakage:
From btrfs_truncate_block() in inode.c:
ret = btrfs_delalloc_reserve_space(inode, &data_reserved,
block_start, blocksize);
if (ret)
goto out;
again:
page = find_or_create_page(mapping, index, mask);
if (!page) {
btrfs_delalloc_release_space(inode, data_reserved,
block_start, blocksize, true);
btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true);
ret = -ENOMEM;
goto out;
}
[CAUSE]
In the above case, btrfs_delalloc_reserve_space() will call
btrfs_qgroup_reserve_data() and mark the io_tree range with
EXTENT_QGROUP_RESERVED flag.
In the error handling path, we have the following call stack:
btrfs_delalloc_release_space()
|- btrfs_free_reserved_data_space()
|- btrsf_qgroup_free_data()
|- __btrfs_qgroup_release_data(reserved=@reserved, free=1)
|- qgroup_free_reserved_data(reserved=@reserved)
|- clear_record_extent_bits();
|- freed += changeset.bytes_changed;
However due to a completion bug, qgroup_free_reserved_data() will clear
EXTENT_QGROUP_RESERVED flag in BTRFS_I(inode)->io_failure_tree, other
than the correct BTRFS_I(inode)->io_tree.
Since io_failure_tree is never marked with that flag,
btrfs_qgroup_free_data() will not free any data reserved space at all,
causing a leakage.
This type of error handling can only be triggered by errors outside of
qgroup code. So EDQUOT error from qgroup can't trigger it.
[FIX]
Fix the wrong target io_tree.
Reported-by: Josef Bacik <josef@toxicpanda.com>
Fixes: bc42bda223 ("btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6af112b11a upstream.
When doing any form of incremental send the parent and the child trees
need to be compared via btrfs_compare_trees. This can result in long
loop chains without ever relinquishing the CPU. This causes softlockup
detector to trigger when comparing trees with a lot of items. Example
report:
watchdog: BUG: soft lockup - CPU#0 stuck for 24s! [snapperd:16153]
CPU: 0 PID: 16153 Comm: snapperd Not tainted 5.2.9-1-default #1 openSUSE Tumbleweed (unreleased)
Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
pstate: 40000005 (nZcv daif -PAN -UAO)
pc : __ll_sc_arch_atomic_sub_return+0x14/0x20
lr : btrfs_release_extent_buffer_pages+0xe0/0x1e8 [btrfs]
sp : ffff00001273b7e0
Call trace:
__ll_sc_arch_atomic_sub_return+0x14/0x20
release_extent_buffer+0xdc/0x120 [btrfs]
free_extent_buffer.part.0+0xb0/0x118 [btrfs]
free_extent_buffer+0x24/0x30 [btrfs]
btrfs_release_path+0x4c/0xa0 [btrfs]
btrfs_free_path.part.0+0x20/0x40 [btrfs]
btrfs_free_path+0x24/0x30 [btrfs]
get_inode_info+0xa8/0xf8 [btrfs]
finish_inode_if_needed+0xe0/0x6d8 [btrfs]
changed_cb+0x9c/0x410 [btrfs]
btrfs_compare_trees+0x284/0x648 [btrfs]
send_subvol+0x33c/0x520 [btrfs]
btrfs_ioctl_send+0x8a0/0xaf0 [btrfs]
btrfs_ioctl+0x199c/0x2288 [btrfs]
do_vfs_ioctl+0x4b0/0x820
ksys_ioctl+0x84/0xb8
__arm64_sys_ioctl+0x28/0x38
el0_svc_common.constprop.0+0x7c/0x188
el0_svc_handler+0x34/0x90
el0_svc+0x8/0xc
Fix this by adding a call to cond_resched at the beginning of the main
loop in btrfs_compare_trees.
Fixes: 7069830a9e ("Btrfs: add btrfs_compare_trees function")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3acd48507d upstream.
Various notifications of type "BUG kmalloc-4096 () : Redzone
overwritten" have been observed recently in various parts of the kernel.
After some time, it has been made a relation with the use of BTRFS
filesystem and with SLUB_DEBUG turned on.
[ 22.809700] BUG kmalloc-4096 (Tainted: G W ): Redzone overwritten
[ 22.810286] INFO: 0xbe1a5921-0xfbfc06cd. First byte 0x0 instead of 0xcc
[ 22.810866] INFO: Allocated in __load_free_space_cache+0x588/0x780 [btrfs] age=22 cpu=0 pid=224
[ 22.811193] __slab_alloc.constprop.26+0x44/0x70
[ 22.811345] kmem_cache_alloc_trace+0xf0/0x2ec
[ 22.811588] __load_free_space_cache+0x588/0x780 [btrfs]
[ 22.811848] load_free_space_cache+0xf4/0x1b0 [btrfs]
[ 22.812090] cache_block_group+0x1d0/0x3d0 [btrfs]
[ 22.812321] find_free_extent+0x680/0x12a4 [btrfs]
[ 22.812549] btrfs_reserve_extent+0xec/0x220 [btrfs]
[ 22.812785] btrfs_alloc_tree_block+0x178/0x5f4 [btrfs]
[ 22.813032] __btrfs_cow_block+0x150/0x5d4 [btrfs]
[ 22.813262] btrfs_cow_block+0x194/0x298 [btrfs]
[ 22.813484] commit_cowonly_roots+0x44/0x294 [btrfs]
[ 22.813718] btrfs_commit_transaction+0x63c/0xc0c [btrfs]
[ 22.813973] close_ctree+0xf8/0x2a4 [btrfs]
[ 22.814107] generic_shutdown_super+0x80/0x110
[ 22.814250] kill_anon_super+0x18/0x30
[ 22.814437] btrfs_kill_super+0x18/0x90 [btrfs]
[ 22.814590] INFO: Freed in proc_cgroup_show+0xc0/0x248 age=41 cpu=0 pid=83
[ 22.814841] proc_cgroup_show+0xc0/0x248
[ 22.814967] proc_single_show+0x54/0x98
[ 22.815086] seq_read+0x278/0x45c
[ 22.815190] __vfs_read+0x28/0x17c
[ 22.815289] vfs_read+0xa8/0x14c
[ 22.815381] ksys_read+0x50/0x94
[ 22.815475] ret_from_syscall+0x0/0x38
Commit 69d2480456 ("btrfs: use copy_page for copying pages instead of
memcpy") changed the way bitmap blocks are copied. But allthough bitmaps
have the size of a page, they were allocated with kzalloc().
Most of the time, kzalloc() allocates aligned blocks of memory, so
copy_page() can be used. But when some debug options like SLAB_DEBUG are
activated, kzalloc() may return unaligned pointer.
On powerpc, memcpy(), copy_page() and other copying functions use
'dcbz' instruction which provides an entire zeroed cacheline to avoid
memory read when the intention is to overwrite a full line. Functions
like memcpy() are writen to care about partial cachelines at the start
and end of the destination, but copy_page() assumes it gets pages. As
pages are naturally cache aligned, copy_page() doesn't care about
partial lines. This means that when copy_page() is called with a
misaligned pointer, a few leading bytes are zeroed.
To fix it, allocate bitmaps through kmem_cache instead of using kzalloc()
The cache pool is created with PAGE_SIZE alignment constraint.
Reported-by: Erhard F. <erhard_f@mailbox.org>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204371
Fixes: 69d2480456 ("btrfs: use copy_page for copying pages instead of memcpy")
Cc: stable@vger.kernel.org # 4.19+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: David Sterba <dsterba@suse.com>
[ rename to btrfs_free_space_bitmap ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 2a28468e52 ]
[BUG]
With fuzzed image and MIXED_GROUPS super flag, we can hit the following
BUG_ON():
kernel BUG at fs/btrfs/delayed-ref.c:491!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 1849 Comm: sync Tainted: G O 5.2.0-custom #27
RIP: 0010:update_existing_head_ref.cold+0x44/0x46 [btrfs]
Call Trace:
add_delayed_ref_head+0x20c/0x2d0 [btrfs]
btrfs_add_delayed_tree_ref+0x1fc/0x490 [btrfs]
btrfs_free_tree_block+0x123/0x380 [btrfs]
__btrfs_cow_block+0x435/0x500 [btrfs]
btrfs_cow_block+0x110/0x240 [btrfs]
btrfs_search_slot+0x230/0xa00 [btrfs]
? __lock_acquire+0x105e/0x1e20
btrfs_insert_empty_items+0x67/0xc0 [btrfs]
alloc_reserved_file_extent+0x9e/0x340 [btrfs]
__btrfs_run_delayed_refs+0x78e/0x1240 [btrfs]
? kvm_clock_read+0x18/0x30
? __sched_clock_gtod_offset+0x21/0x50
btrfs_run_delayed_refs.part.0+0x4e/0x180 [btrfs]
btrfs_run_delayed_refs+0x23/0x30 [btrfs]
btrfs_commit_transaction+0x53/0x9f0 [btrfs]
btrfs_sync_fs+0x7c/0x1c0 [btrfs]
? __ia32_sys_fdatasync+0x20/0x20
sync_fs_one_sb+0x23/0x30
iterate_supers+0x95/0x100
ksys_sync+0x62/0xb0
__ia32_sys_sync+0xe/0x20
do_syscall_64+0x65/0x240
entry_SYSCALL_64_after_hwframe+0x49/0xbe
[CAUSE]
This situation is caused by several factors:
- Fuzzed image
The extent tree of this fs missed one backref for extent tree root.
So we can allocated space from that slot.
- MIXED_BG feature
Super block has MIXED_BG flag.
- No mixed block groups exists
All block groups are just regular ones.
This makes data space_info->block_groups[] contains metadata block
groups. And when we reserve space for data, we can use space in
metadata block group.
Then we hit the following file operations:
- fallocate
We need to allocate data extents.
find_free_extent() choose to use the metadata block to allocate space
from, and choose the space of extent tree root, since its backref is
missing.
This generate one delayed ref head with is_data = 1.
- extent tree update
We need to update extent tree at run_delayed_ref time.
This generate one delayed ref head with is_data = 0, for the same
bytenr of old extent tree root.
Then we trigger the BUG_ON().
[FIX]
The quick fix here is to check block_group->flags before using it.
The problem can only happen for MIXED_GROUPS fs. Regular filesystems
won't have space_info with DATA|METADATA flag, and no way to hit the
bug.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203255
Reported-by: Jungyeon Yoon <jungyeon.yoon@gmail.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 410f954cb1 upstream.
Sometimes when fsync'ing a file we need to log that other inodes exist and
when we need to do that we acquire a reference on the inodes and then drop
that reference using iput() after logging them.
That generally is not a problem except if we end up doing the final iput()
(dropping the last reference) on the inode and that inode has a link count
of 0, which can happen in a very short time window if the logging path
gets a reference on the inode while it's being unlinked.
In that case we end up getting the eviction callback, btrfs_evict_inode(),
invoked through the iput() call chain which needs to drop all of the
inode's items from its subvolume btree, and in order to do that, it needs
to join a transaction at the helper function evict_refill_and_join().
However because the task previously started a transaction at the fsync
handler, btrfs_sync_file(), it has current->journal_info already pointing
to a transaction handle and therefore evict_refill_and_join() will get
that transaction handle from btrfs_join_transaction(). From this point on,
two different problems can happen:
1) evict_refill_and_join() will often change the transaction handle's
block reserve (->block_rsv) and set its ->bytes_reserved field to a
value greater than 0. If evict_refill_and_join() never commits the
transaction, the eviction handler ends up decreasing the reference
count (->use_count) of the transaction handle through the call to
btrfs_end_transaction(), and after that point we have a transaction
handle with a NULL ->block_rsv (which is the value prior to the
transaction join from evict_refill_and_join()) and a ->bytes_reserved
value greater than 0. If after the eviction/iput completes the inode
logging path hits an error or it decides that it must fallback to a
transaction commit, the btrfs fsync handle, btrfs_sync_file(), gets a
non-zero value from btrfs_log_dentry_safe(), and because of that
non-zero value it tries to commit the transaction using a handle with
a NULL ->block_rsv and a non-zero ->bytes_reserved value. This makes
the transaction commit hit an assertion failure at
btrfs_trans_release_metadata() because ->bytes_reserved is not zero but
the ->block_rsv is NULL. The produced stack trace for that is like the
following:
[192922.917158] assertion failed: !trans->bytes_reserved, file: fs/btrfs/transaction.c, line: 816
[192922.917553] ------------[ cut here ]------------
[192922.917922] kernel BUG at fs/btrfs/ctree.h:3532!
[192922.918310] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
[192922.918666] CPU: 2 PID: 883 Comm: fsstress Tainted: G W 5.1.4-btrfs-next-47 #1
[192922.919035] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[192922.919801] RIP: 0010:assfail.constprop.25+0x18/0x1a [btrfs]
(...)
[192922.920925] RSP: 0018:ffffaebdc8a27da8 EFLAGS: 00010286
[192922.921315] RAX: 0000000000000051 RBX: ffff95c9c16a41c0 RCX: 0000000000000000
[192922.921692] RDX: 0000000000000000 RSI: ffff95cab6b16838 RDI: ffff95cab6b16838
[192922.922066] RBP: ffff95c9c16a41c0 R08: 0000000000000000 R09: 0000000000000000
[192922.922442] R10: ffffaebdc8a27e70 R11: 0000000000000000 R12: ffff95ca731a0980
[192922.922820] R13: 0000000000000000 R14: ffff95ca84c73338 R15: ffff95ca731a0ea8
[192922.923200] FS: 00007f337eda4e80(0000) GS:ffff95cab6b00000(0000) knlGS:0000000000000000
[192922.923579] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[192922.923948] CR2: 00007f337edad000 CR3: 00000001e00f6002 CR4: 00000000003606e0
[192922.924329] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[192922.924711] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[192922.925105] Call Trace:
[192922.925505] btrfs_trans_release_metadata+0x10c/0x170 [btrfs]
[192922.925911] btrfs_commit_transaction+0x3e/0xaf0 [btrfs]
[192922.926324] btrfs_sync_file+0x44c/0x490 [btrfs]
[192922.926731] do_fsync+0x38/0x60
[192922.927138] __x64_sys_fdatasync+0x13/0x20
[192922.927543] do_syscall_64+0x60/0x1c0
[192922.927939] entry_SYSCALL_64_after_hwframe+0x49/0xbe
(...)
[192922.934077] ---[ end trace f00808b12068168f ]---
2) If evict_refill_and_join() decides to commit the transaction, it will
be able to do it, since the nested transaction join only increments the
transaction handle's ->use_count reference counter and it does not
prevent the transaction from getting committed. This means that after
eviction completes, the fsync logging path will be using a transaction
handle that refers to an already committed transaction. What happens
when using such a stale transaction can be unpredictable, we are at
least having a use-after-free on the transaction handle itself, since
the transaction commit will call kmem_cache_free() against the handle
regardless of its ->use_count value, or we can end up silently losing
all the updates to the log tree after that iput() in the logging path,
or using a transaction handle that in the meanwhile was allocated to
another task for a new transaction, etc, pretty much unpredictable
what can happen.
In order to fix both of them, instead of using iput() during logging, use
btrfs_add_delayed_iput(), so that the logging path of fsync never drops
the last reference on an inode, that step is offloaded to a safe context
(usually the cleaner kthread).
The assertion failure issue was sporadically triggered by the test case
generic/475 from fstests, which loads the dm error target while fsstress
is running, which lead to fsync failing while logging inodes with -EIO
errors and then trying later to commit the transaction, triggering the
assertion failure.
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit aa53e3bfac ]
Nikolay reported the following KASAN splat when running btrfs/048:
[ 1843.470920] ==================================================================
[ 1843.471971] BUG: KASAN: slab-out-of-bounds in strncmp+0x66/0xb0
[ 1843.472775] Read of size 1 at addr ffff888111e369e2 by task btrfs/3979
[ 1843.473904] CPU: 3 PID: 3979 Comm: btrfs Not tainted 5.2.0-rc3-default #536
[ 1843.475009] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[ 1843.476322] Call Trace:
[ 1843.476674] dump_stack+0x7c/0xbb
[ 1843.477132] ? strncmp+0x66/0xb0
[ 1843.477587] print_address_description+0x114/0x320
[ 1843.478256] ? strncmp+0x66/0xb0
[ 1843.478740] ? strncmp+0x66/0xb0
[ 1843.479185] __kasan_report+0x14e/0x192
[ 1843.479759] ? strncmp+0x66/0xb0
[ 1843.480209] kasan_report+0xe/0x20
[ 1843.480679] strncmp+0x66/0xb0
[ 1843.481105] prop_compression_validate+0x24/0x70
[ 1843.481798] btrfs_xattr_handler_set_prop+0x65/0x160
[ 1843.482509] __vfs_setxattr+0x71/0x90
[ 1843.483012] __vfs_setxattr_noperm+0x84/0x130
[ 1843.483606] vfs_setxattr+0xac/0xb0
[ 1843.484085] setxattr+0x18c/0x230
[ 1843.484546] ? vfs_setxattr+0xb0/0xb0
[ 1843.485048] ? __mod_node_page_state+0x1f/0xa0
[ 1843.485672] ? _raw_spin_unlock+0x24/0x40
[ 1843.486233] ? __handle_mm_fault+0x988/0x1290
[ 1843.486823] ? lock_acquire+0xb4/0x1e0
[ 1843.487330] ? lock_acquire+0xb4/0x1e0
[ 1843.487842] ? mnt_want_write_file+0x3c/0x80
[ 1843.488442] ? debug_lockdep_rcu_enabled+0x22/0x40
[ 1843.489089] ? rcu_sync_lockdep_assert+0xe/0x70
[ 1843.489707] ? __sb_start_write+0x158/0x200
[ 1843.490278] ? mnt_want_write_file+0x3c/0x80
[ 1843.490855] ? __mnt_want_write+0x98/0xe0
[ 1843.491397] __x64_sys_fsetxattr+0xba/0xe0
[ 1843.492201] ? trace_hardirqs_off_thunk+0x1a/0x1c
[ 1843.493201] do_syscall_64+0x6c/0x230
[ 1843.493988] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1843.495041] RIP: 0033:0x7fa7a8a7707a
[ 1843.495819] Code: 48 8b 0d 21 de 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 be 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ee dd 2b 00 f7 d8 64 89 01 48
[ 1843.499203] RSP: 002b:00007ffcb73bca38 EFLAGS: 00000202 ORIG_RAX: 00000000000000be
[ 1843.500210] RAX: ffffffffffffffda RBX: 00007ffcb73bda9d RCX: 00007fa7a8a7707a
[ 1843.501170] RDX: 00007ffcb73bda9d RSI: 00000000006dc050 RDI: 0000000000000003
[ 1843.502152] RBP: 00000000006dc050 R08: 0000000000000000 R09: 0000000000000000
[ 1843.503109] R10: 0000000000000002 R11: 0000000000000202 R12: 00007ffcb73bda91
[ 1843.504055] R13: 0000000000000003 R14: 00007ffcb73bda82 R15: ffffffffffffffff
[ 1843.505268] Allocated by task 3979:
[ 1843.505771] save_stack+0x19/0x80
[ 1843.506211] __kasan_kmalloc.constprop.5+0xa0/0xd0
[ 1843.506836] setxattr+0xeb/0x230
[ 1843.507264] __x64_sys_fsetxattr+0xba/0xe0
[ 1843.507886] do_syscall_64+0x6c/0x230
[ 1843.508429] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 1843.509558] Freed by task 0:
[ 1843.510188] (stack is not available)
[ 1843.511309] The buggy address belongs to the object at ffff888111e369e0
which belongs to the cache kmalloc-8 of size 8
[ 1843.514095] The buggy address is located 2 bytes inside of
8-byte region [ffff888111e369e0, ffff888111e369e8)
[ 1843.516524] The buggy address belongs to the page:
[ 1843.517561] page:ffff88813f478d80 refcount:1 mapcount:0 mapping:ffff88811940c300 index:0xffff888111e373b8 compound_mapcount: 0
[ 1843.519993] flags: 0x4404000010200(slab|head)
[ 1843.520951] raw: 0004404000010200 ffff88813f48b008 ffff888119403d50 ffff88811940c300
[ 1843.522616] raw: ffff888111e373b8 000000000016000f 00000001ffffffff 0000000000000000
[ 1843.524281] page dumped because: kasan: bad access detected
[ 1843.525936] Memory state around the buggy address:
[ 1843.526975] ffff888111e36880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1843.528479] ffff888111e36900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1843.530138] >ffff888111e36980: fc fc fc fc fc fc fc fc fc fc fc fc 02 fc fc fc
[ 1843.531877] ^
[ 1843.533287] ffff888111e36a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1843.534874] ffff888111e36a80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[ 1843.536468] ==================================================================
This is caused by supplying a too short compression value ('lz') in the
test-case and comparing it to 'lzo' with strncmp() and a length of 3.
strncmp() read past the 'lz' when looking for the 'o' and thus caused an
out-of-bounds read.
Introduce a new check 'btrfs_compress_is_valid_type()' which not only
checks the user-supplied value against known compression types, but also
employs checks for too short values.
Reported-by: Nikolay Borisov <nborisov@suse.com>
Fixes: 272e5326c7 ("btrfs: prop: fix vanished compression property after failed set")
CC: stable@vger.kernel.org # 5.1+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 8eaf40c0e2 ]
If a task is removing the block group that currently has the highest start
offset amongst all existing block groups, there is a short time window
where it races with a concurrent block group allocation, resulting in a
transaction abort with an error code of EEXIST.
The following diagram explains the race in detail:
Task A Task B
btrfs_remove_block_group(bg offset X)
remove_extent_mapping(em offset X)
-> removes extent map X from the
tree of extent maps
(fs_info->mapping_tree), so the
next call to find_next_chunk()
will return offset X
btrfs_alloc_chunk()
find_next_chunk()
--> returns offset X
__btrfs_alloc_chunk(offset X)
btrfs_make_block_group()
btrfs_create_block_group_cache()
--> creates btrfs_block_group_cache
object with a key corresponding
to the block group item in the
extent, the key is:
(offset X, BTRFS_BLOCK_GROUP_ITEM_KEY, 1G)
--> adds the btrfs_block_group_cache object
to the list new_bgs of the transaction
handle
btrfs_end_transaction(trans handle)
__btrfs_end_transaction()
btrfs_create_pending_block_groups()
--> sees the new btrfs_block_group_cache
in the new_bgs list of the transaction
handle
--> its call to btrfs_insert_item() fails
with -EEXIST when attempting to insert
the block group item key
(offset X, BTRFS_BLOCK_GROUP_ITEM_KEY, 1G)
because task A has not removed that key yet
--> aborts the running transaction with
error -EEXIST
btrfs_del_item()
-> removes the block group's key from
the extent tree, key is
(offset X, BTRFS_BLOCK_GROUP_ITEM_KEY, 1G)
A sample transaction abort trace:
[78912.403537] ------------[ cut here ]------------
[78912.403811] BTRFS: Transaction aborted (error -17)
[78912.404082] WARNING: CPU: 2 PID: 20465 at fs/btrfs/extent-tree.c:10551 btrfs_create_pending_block_groups+0x196/0x250 [btrfs]
(...)
[78912.405642] CPU: 2 PID: 20465 Comm: btrfs Tainted: G W 5.0.0-btrfs-next-46 #1
[78912.405941] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014
[78912.406586] RIP: 0010:btrfs_create_pending_block_groups+0x196/0x250 [btrfs]
(...)
[78912.407636] RSP: 0018:ffff9d3d4b7e3b08 EFLAGS: 00010282
[78912.407997] RAX: 0000000000000000 RBX: ffff90959a3796f0 RCX: 0000000000000006
[78912.408369] RDX: 0000000000000007 RSI: 0000000000000001 RDI: ffff909636b16860
[78912.408746] RBP: ffff909626758a58 R08: 0000000000000000 R09: 0000000000000000
[78912.409144] R10: ffff9095ff462400 R11: 0000000000000000 R12: ffff90959a379588
[78912.409521] R13: ffff909626758ab0 R14: ffff9095036c0000 R15: ffff9095299e1158
[78912.409899] FS: 00007f387f16f700(0000) GS:ffff909636b00000(0000) knlGS:0000000000000000
[78912.410285] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[78912.410673] CR2: 00007f429fc87cbc CR3: 000000014440a004 CR4: 00000000003606e0
[78912.411095] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[78912.411496] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[78912.411898] Call Trace:
[78912.412318] __btrfs_end_transaction+0x5b/0x1c0 [btrfs]
[78912.412746] btrfs_inc_block_group_ro+0xcf/0x160 [btrfs]
[78912.413179] scrub_enumerate_chunks+0x188/0x5b0 [btrfs]
[78912.413622] ? __mutex_unlock_slowpath+0x100/0x2a0
[78912.414078] btrfs_scrub_dev+0x2ef/0x720 [btrfs]
[78912.414535] ? __sb_start_write+0xd4/0x1c0
[78912.414963] ? mnt_want_write_file+0x24/0x50
[78912.415403] btrfs_ioctl+0x17fb/0x3120 [btrfs]
[78912.415832] ? lock_acquire+0xa6/0x190
[78912.416256] ? do_vfs_ioctl+0xa2/0x6f0
[78912.416685] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[78912.417116] do_vfs_ioctl+0xa2/0x6f0
[78912.417534] ? __fget+0x113/0x200
[78912.417954] ksys_ioctl+0x70/0x80
[78912.418369] __x64_sys_ioctl+0x16/0x20
[78912.418812] do_syscall_64+0x60/0x1b0
[78912.419231] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[78912.419644] RIP: 0033:0x7f3880252dd7
(...)
[78912.420957] RSP: 002b:00007f387f16ed68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[78912.421426] RAX: ffffffffffffffda RBX: 000055f5becc1df0 RCX: 00007f3880252dd7
[78912.421889] RDX: 000055f5becc1df0 RSI: 00000000c400941b RDI: 0000000000000003
[78912.422354] RBP: 0000000000000000 R08: 00007f387f16f700 R09: 0000000000000000
[78912.422790] R10: 00007f387f16f700 R11: 0000000000000246 R12: 0000000000000000
[78912.423202] R13: 00007ffda49c266f R14: 0000000000000000 R15: 00007f388145e040
[78912.425505] ---[ end trace eb9bfe7c426fc4d3 ]---
Fix this by calling remove_extent_mapping(), at btrfs_remove_block_group(),
only at the very end, after removing the block group item key from the
extent tree (and removing the free space tree entry if we are using the
free space tree feature).
Fixes: 04216820fe ("Btrfs: fix race between fs trimming and block group remove/allocation")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit e49be14b8d ]
The scrub_ctx csum_list member must be initialized before scrub_free_ctx
is called. If the csum_list is not initialized beforehand, the
list_empty call in scrub_free_csums will result in a null deref if the
allocation fails in the for loop.
Fixes: a2de733c78 ("btrfs: scrub")
CC: stable@vger.kernel.org # 3.0+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Dan Robertson <dan@dlrobertson.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 0e94c4f45d ]
The scrub context is allocated with GFP_KERNEL and called from
btrfs_scrub_dev under the fs_info::device_list_mutex. This is not safe
regarding reclaim that could try to flush filesystem data in order to
get the memory. And the device_list_mutex is held during superblock
commit, so this would cause a lockup.
Move the alocation and initialization before any changes that require
the mutex.
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 92f7ba434f ]
We can pass fs_info directly as this is the only member of btrfs_device
that's bing used inside scrub_setup_ctx.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1b3922a8bc ]
[BUG]
Linux v5.0-rc1 will fail fstests/btrfs/163 with the following kernel
message:
BTRFS error (device dm-6): dev extent devid 1 physical offset 13631488 len 8388608 is beyond device boundary 0
BTRFS error (device dm-6): failed to verify dev extents against chunks: -117
BTRFS error (device dm-6): open_ctree failed
[CAUSE]
Commit cf90d884b3 ("btrfs: Introduce mount time chunk <-> dev extent
mapping check") introduced strict check on dev extents.
We use btrfs_find_device() with dev uuid and fs uuid set to NULL, and
only dependent on @devid to find the real device.
For seed devices, we call clone_fs_devices() in open_seed_devices() to
allow us search seed devices directly.
However clone_fs_devices() just populates devices with devid and dev
uuid, without populating other essential members, like disk_total_bytes.
This makes any device returned by btrfs_find_device(fs_info, devid,
NULL, NULL) is just a dummy, with 0 disk_total_bytes, and any dev
extents on the seed device will not pass the device boundary check.
[FIX]
This patch will try to verify the device returned by btrfs_find_device()
and if it's a dummy then re-search in seed devices.
Fixes: cf90d884b3 ("btrfs: Introduce mount time chunk <-> dev extent mapping check")
CC: stable@vger.kernel.org # 4.19+
Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 05a37c4860 ]
Add extra dev extent end check against device boundary.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit d1051d6ebf ]
Running btrfs/124 in a loop hung up on me sporadically with the
following call trace:
btrfs D 0 5760 5324 0x00000000
Call Trace:
? __schedule+0x243/0x800
schedule+0x33/0x90
btrfs_start_ordered_extent+0x10c/0x1b0 [btrfs]
? wait_woken+0xa0/0xa0
btrfs_wait_ordered_range+0xbb/0x100 [btrfs]
btrfs_relocate_block_group+0x1ff/0x230 [btrfs]
btrfs_relocate_chunk+0x49/0x100 [btrfs]
btrfs_balance+0xbeb/0x1740 [btrfs]
btrfs_ioctl_balance+0x2ee/0x380 [btrfs]
btrfs_ioctl+0x1691/0x3110 [btrfs]
? lockdep_hardirqs_on+0xed/0x180
? __handle_mm_fault+0x8e7/0xfb0
? _raw_spin_unlock+0x24/0x30
? __handle_mm_fault+0x8e7/0xfb0
? do_vfs_ioctl+0xa5/0x6e0
? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
do_vfs_ioctl+0xa5/0x6e0
? entry_SYSCALL_64_after_hwframe+0x3e/0xbe
ksys_ioctl+0x3a/0x70
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x60/0x1b0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
This happens because during page writeback it's valid for
writepage_delalloc to instantiate a delalloc range which doesn't belong
to the page currently being written back.
The reason this case is valid is due to find_lock_delalloc_range
returning any available range after the passed delalloc_start and
ignoring whether the page under writeback is within that range.
In turn ordered extents (OE) are always created for the returned range
from find_lock_delalloc_range. If, however, a failure occurs while OE
are being created then the clean up code in btrfs_cleanup_ordered_extents
will be called.
Unfortunately the code in btrfs_cleanup_ordered_extents doesn't consider
the case of such 'foreign' range being processed and instead it always
assumes that the range OE are created for belongs to the page. This
leads to the first page of such foregin range to not be cleaned up since
it's deliberately missed and skipped by the current cleaning up code.
Fix this by correctly checking whether the current page belongs to the
range being instantiated and if so adjsut the range parameters passed
for cleaning up. If it doesn't, then just clean the whole OE range
directly.
Fixes: 524272607e ("btrfs: Handle delalloc error correctly to avoid ordered extent hang")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 5eaad97af8 ]
This callback is called only from writepage_delalloc which in turn is
guaranteed to be called from the data page writeout path. In the end
there is no reason to have the call to this function to be indrected via
the extent_io_ops structure. This patch removes the callback definition,
exports the function and calls it directly. No functional changes.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ rename to btrfs_run_delalloc_range ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a5fb114291 ]
When a transaction commit starts, it attempts to pause scrub and it blocks
until the scrub is paused. So while the transaction is blocked waiting for
scrub to pause, we can not do memory allocation with GFP_KERNEL from scrub,
otherwise we risk getting into a deadlock with reclaim.
Checking for scrub pause requests is done early at the beginning of the
while loop of scrub_stripe() and later in the loop, scrub_extent() and
scrub_raid56_parity() are called, which in turn call scrub_pages() and
scrub_pages_for_parity() respectively. These last two functions do memory
allocations using GFP_KERNEL. Same problem could happen while scrubbing
the super blocks, since it calls scrub_pages().
We also can not have any of the worker tasks, created by the scrub task,
doing GFP_KERNEL allocations, because before pausing, the scrub task waits
for all the worker tasks to complete (also done at scrub_stripe()).
So make sure GFP_NOFS is used for the memory allocations because at any
time a scrub pause request can happen from another task that started to
commit a transaction.
Fixes: 58c4e17384 ("btrfs: scrub: use GFP_KERNEL on the submission path")
CC: stable@vger.kernel.org # 4.6+
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3293428096 ]
struct scrub_ctx has an ->is_dev_replace member, so there's no point in
passing around is_dev_replace where sctx is available.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a6d155d2e3 ]
The fiemap handler locks a file range that can have unflushed delalloc,
and after locking the range, it tries to attach to a running transaction.
If the running transaction started its commit, that is, it is in state
TRANS_STATE_COMMIT_START, and either the filesystem was mounted with the
flushoncommit option or the transaction is creating a snapshot for the
subvolume that contains the file that fiemap is operating on, we end up
deadlocking. This happens because fiemap is blocked on the transaction,
waiting for it to complete, and the transaction is waiting for the flushed
dealloc to complete, which requires locking the file range that the fiemap
task already locked. The following stack traces serve as an example of
when this deadlock happens:
(...)
[404571.515510] Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs]
[404571.515956] Call Trace:
[404571.516360] ? __schedule+0x3ae/0x7b0
[404571.516730] schedule+0x3a/0xb0
[404571.517104] lock_extent_bits+0x1ec/0x2a0 [btrfs]
[404571.517465] ? remove_wait_queue+0x60/0x60
[404571.517832] btrfs_finish_ordered_io+0x292/0x800 [btrfs]
[404571.518202] normal_work_helper+0xea/0x530 [btrfs]
[404571.518566] process_one_work+0x21e/0x5c0
[404571.518990] worker_thread+0x4f/0x3b0
[404571.519413] ? process_one_work+0x5c0/0x5c0
[404571.519829] kthread+0x103/0x140
[404571.520191] ? kthread_create_worker_on_cpu+0x70/0x70
[404571.520565] ret_from_fork+0x3a/0x50
[404571.520915] kworker/u8:6 D 0 31651 2 0x80004000
[404571.521290] Workqueue: btrfs-flush_delalloc btrfs_flush_delalloc_helper [btrfs]
(...)
[404571.537000] fsstress D 0 13117 13115 0x00004000
[404571.537263] Call Trace:
[404571.537524] ? __schedule+0x3ae/0x7b0
[404571.537788] schedule+0x3a/0xb0
[404571.538066] wait_current_trans+0xc8/0x100 [btrfs]
[404571.538349] ? remove_wait_queue+0x60/0x60
[404571.538680] start_transaction+0x33c/0x500 [btrfs]
[404571.539076] btrfs_check_shared+0xa3/0x1f0 [btrfs]
[404571.539513] ? extent_fiemap+0x2ce/0x650 [btrfs]
[404571.539866] extent_fiemap+0x2ce/0x650 [btrfs]
[404571.540170] do_vfs_ioctl+0x526/0x6f0
[404571.540436] ksys_ioctl+0x70/0x80
[404571.540734] __x64_sys_ioctl+0x16/0x20
[404571.540997] do_syscall_64+0x60/0x1d0
[404571.541279] entry_SYSCALL_64_after_hwframe+0x49/0xbe
(...)
[404571.543729] btrfs D 0 14210 14208 0x00004000
[404571.544023] Call Trace:
[404571.544275] ? __schedule+0x3ae/0x7b0
[404571.544526] ? wait_for_completion+0x112/0x1a0
[404571.544795] schedule+0x3a/0xb0
[404571.545064] schedule_timeout+0x1ff/0x390
[404571.545351] ? lock_acquire+0xa6/0x190
[404571.545638] ? wait_for_completion+0x49/0x1a0
[404571.545890] ? wait_for_completion+0x112/0x1a0
[404571.546228] wait_for_completion+0x131/0x1a0
[404571.546503] ? wake_up_q+0x70/0x70
[404571.546775] btrfs_wait_ordered_extents+0x27c/0x400 [btrfs]
[404571.547159] btrfs_commit_transaction+0x3b0/0xae0 [btrfs]
[404571.547449] ? btrfs_mksubvol+0x4a4/0x640 [btrfs]
[404571.547703] ? remove_wait_queue+0x60/0x60
[404571.547969] btrfs_mksubvol+0x605/0x640 [btrfs]
[404571.548226] ? __sb_start_write+0xd4/0x1c0
[404571.548512] ? mnt_want_write_file+0x24/0x50
[404571.548789] btrfs_ioctl_snap_create_transid+0x169/0x1a0 [btrfs]
[404571.549048] btrfs_ioctl_snap_create_v2+0x11d/0x170 [btrfs]
[404571.549307] btrfs_ioctl+0x133f/0x3150 [btrfs]
[404571.549549] ? mem_cgroup_charge_statistics+0x4c/0xd0
[404571.549792] ? mem_cgroup_commit_charge+0x84/0x4b0
[404571.550064] ? __handle_mm_fault+0xe3e/0x11f0
[404571.550306] ? do_raw_spin_unlock+0x49/0xc0
[404571.550608] ? _raw_spin_unlock+0x24/0x30
[404571.550976] ? __handle_mm_fault+0xedf/0x11f0
[404571.551319] ? do_vfs_ioctl+0xa2/0x6f0
[404571.551659] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs]
[404571.552087] do_vfs_ioctl+0xa2/0x6f0
[404571.552355] ksys_ioctl+0x70/0x80
[404571.552621] __x64_sys_ioctl+0x16/0x20
[404571.552864] do_syscall_64+0x60/0x1d0
[404571.553104] entry_SYSCALL_64_after_hwframe+0x49/0xbe
(...)
If we were joining the transaction instead of attaching to it, we would
not risk a deadlock because a join only blocks if the transaction is in a
state greater then or equals to TRANS_STATE_COMMIT_DOING, and the delalloc
flush performed by a transaction is done before it reaches that state,
when it is in the state TRANS_STATE_COMMIT_START. However a transaction
join is intended for use cases where we do modify the filesystem, and
fiemap only needs to peek at delayed references from the current
transaction in order to determine if extents are shared, and, besides
that, when there is no current transaction or when it blocks to wait for
a current committing transaction to complete, it creates a new transaction
without reserving any space. Such unnecessary transactions, besides doing
unnecessary IO, can cause transaction aborts (-ENOSPC) and unnecessary
rotation of the precious backup roots.
So fix this by adding a new transaction join variant, named join_nostart,
which behaves like the regular join, but it does not create a transaction
when none currently exists or after waiting for a committing transaction
to complete.
Fixes: 03628cdbc6 ("Btrfs: do not start a transaction during fiemap")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit cb2d3daddb upstream.
When one transaction is finishing its commit, it is possible for another
transaction to start and enter its initial commit phase as well. If the
first ends up getting aborted, we have a small time window where the second
transaction commit does not notice that the previous transaction aborted
and ends up committing, writing a superblock that points to btrees that
reference extent buffers (nodes and leafs) that were not persisted to disk.
The consequence is that after mounting the filesystem again, we will be
unable to load some btree nodes/leafs, either because the content on disk
is either garbage (or just zeroes) or corresponds to the old content of a
previouly COWed or deleted node/leaf, resulting in the well known error
messages "parent transid verify failed on ...".
The following sequence diagram illustrates how this can happen.
CPU 1 CPU 2
<at transaction N>
btrfs_commit_transaction()
(...)
--> sets transaction state to
TRANS_STATE_UNBLOCKED
--> sets fs_info->running_transaction
to NULL
(...)
btrfs_start_transaction()
start_transaction()
wait_current_trans()
--> returns immediately
because
fs_info->running_transaction
is NULL
join_transaction()
--> creates transaction N + 1
--> sets
fs_info->running_transaction
to transaction N + 1
--> adds transaction N + 1 to
the fs_info->trans_list list
--> returns transaction handle
pointing to the new
transaction N + 1
(...)
btrfs_sync_file()
btrfs_start_transaction()
--> returns handle to
transaction N + 1
(...)
btrfs_write_and_wait_transaction()
--> writeback of some extent
buffer fails, returns an
error
btrfs_handle_fs_error()
--> sets BTRFS_FS_STATE_ERROR in
fs_info->fs_state
--> jumps to label "scrub_continue"
cleanup_transaction()
btrfs_abort_transaction(N)
--> sets BTRFS_FS_STATE_TRANS_ABORTED
flag in fs_info->fs_state
--> sets aborted field in the
transaction and transaction
handle structures, for
transaction N only
--> removes transaction from the
list fs_info->trans_list
btrfs_commit_transaction(N + 1)
--> transaction N + 1 was not
aborted, so it proceeds
(...)
--> sets the transaction's state
to TRANS_STATE_COMMIT_START
--> does not find the previous
transaction (N) in the
fs_info->trans_list, so it
doesn't know that transaction
was aborted, and the commit
of transaction N + 1 proceeds
(...)
--> sets transaction N + 1 state
to TRANS_STATE_UNBLOCKED
btrfs_write_and_wait_transaction()
--> succeeds writing all extent
buffers created in the
transaction N + 1
write_all_supers()
--> succeeds
--> we now have a superblock on
disk that points to trees
that refer to at least one
extent buffer that was
never persisted
So fix this by updating the transaction commit path to check if the flag
BTRFS_FS_STATE_TRANS_ABORTED is set on fs_info->fs_state if after setting
the transaction to the TRANS_STATE_COMMIT_START we do not find any previous
transaction in the fs_info->trans_list. If the flag is set, just fail the
transaction commit with -EROFS, as we do in other places. The exact error
code for the previous transaction abort was already logged and reported.
Fixes: 49b25e0540 ("btrfs: enhance transaction abort infrastructure")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b4f9a1a87a upstream.
When doing an incremental send operation we can fail if we previously did
deduplication operations against a file that exists in both snapshots. In
that case we will fail the send operation with -EIO and print a message
to dmesg/syslog like the following:
BTRFS error (device sdc): Send: inconsistent snapshot, found updated \
extent for inode 257 without updated inode item, send root is 258, \
parent root is 257
This requires that we deduplicate to the same file in both snapshots for
the same amount of times on each snapshot. The issue happens because a
deduplication only updates the iversion of an inode and does not update
any other field of the inode, therefore if we deduplicate the file on
each snapshot for the same amount of time, the inode will have the same
iversion value (stored as the "sequence" field on the inode item) on both
snapshots, therefore it will be seen as unchanged between in the send
snapshot while there are new/updated/deleted extent items when comparing
to the parent snapshot. This makes the send operation return -EIO and
print an error message.
Example reproducer:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
# Create our first file. The first half of the file has several 64Kb
# extents while the second half as a single 512Kb extent.
$ xfs_io -f -s -c "pwrite -S 0xb8 -b 64K 0 512K" /mnt/foo
$ xfs_io -c "pwrite -S 0xb8 512K 512K" /mnt/foo
# Create the base snapshot and the parent send stream from it.
$ btrfs subvolume snapshot -r /mnt /mnt/mysnap1
$ btrfs send -f /tmp/1.snap /mnt/mysnap1
# Create our second file, that has exactly the same data as the first
# file.
$ xfs_io -f -c "pwrite -S 0xb8 0 1M" /mnt/bar
# Create the second snapshot, used for the incremental send, before
# doing the file deduplication.
$ btrfs subvolume snapshot -r /mnt /mnt/mysnap2
# Now before creating the incremental send stream:
#
# 1) Deduplicate into a subrange of file foo in snapshot mysnap1. This
# will drop several extent items and add a new one, also updating
# the inode's iversion (sequence field in inode item) by 1, but not
# any other field of the inode;
#
# 2) Deduplicate into a different subrange of file foo in snapshot
# mysnap2. This will replace an extent item with a new one, also
# updating the inode's iversion by 1 but not any other field of the
# inode.
#
# After these two deduplication operations, the inode items, for file
# foo, are identical in both snapshots, but we have different extent
# items for this inode in both snapshots. We want to check this doesn't
# cause send to fail with an error or produce an incorrect stream.
$ xfs_io -r -c "dedupe /mnt/bar 0 0 512K" /mnt/mysnap1/foo
$ xfs_io -r -c "dedupe /mnt/bar 512K 512K 512K" /mnt/mysnap2/foo
# Create the incremental send stream.
$ btrfs send -p /mnt/mysnap1 -f /tmp/2.snap /mnt/mysnap2
ERROR: send ioctl failed with -5: Input/output error
This issue started happening back in 2015 when deduplication was updated
to not update the inode's ctime and mtime and update only the iversion.
Back then we would hit a BUG_ON() in send, but later in 2016 send was
updated to return -EIO and print the error message instead of doing the
BUG_ON().
A test case for fstests follows soon.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203933
Fixes: 1c919a5e13 ("btrfs: don't update mtime/ctime on deduped inodes")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit e88439debd ]
[BUG]
Lockdep will report the following circular locking dependency:
WARNING: possible circular locking dependency detected
5.2.0-rc2-custom #24 Tainted: G O
------------------------------------------------------
btrfs/8631 is trying to acquire lock:
000000002536438c (&fs_info->qgroup_ioctl_lock#2){+.+.}, at: btrfs_qgroup_inherit+0x40/0x620 [btrfs]
but task is already holding lock:
000000003d52cc23 (&fs_info->tree_log_mutex){+.+.}, at: create_pending_snapshot+0x8b6/0xe60 [btrfs]
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&fs_info->tree_log_mutex){+.+.}:
__mutex_lock+0x76/0x940
mutex_lock_nested+0x1b/0x20
btrfs_commit_transaction+0x475/0xa00 [btrfs]
btrfs_commit_super+0x71/0x80 [btrfs]
close_ctree+0x2bd/0x320 [btrfs]
btrfs_put_super+0x15/0x20 [btrfs]
generic_shutdown_super+0x72/0x110
kill_anon_super+0x18/0x30
btrfs_kill_super+0x16/0xa0 [btrfs]
deactivate_locked_super+0x3a/0x80
deactivate_super+0x51/0x60
cleanup_mnt+0x3f/0x80
__cleanup_mnt+0x12/0x20
task_work_run+0x94/0xb0
exit_to_usermode_loop+0xd8/0xe0
do_syscall_64+0x210/0x240
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #1 (&fs_info->reloc_mutex){+.+.}:
__mutex_lock+0x76/0x940
mutex_lock_nested+0x1b/0x20
btrfs_commit_transaction+0x40d/0xa00 [btrfs]
btrfs_quota_enable+0x2da/0x730 [btrfs]
btrfs_ioctl+0x2691/0x2b40 [btrfs]
do_vfs_ioctl+0xa9/0x6d0
ksys_ioctl+0x67/0x90
__x64_sys_ioctl+0x1a/0x20
do_syscall_64+0x65/0x240
entry_SYSCALL_64_after_hwframe+0x49/0xbe
-> #0 (&fs_info->qgroup_ioctl_lock#2){+.+.}:
lock_acquire+0xa7/0x190
__mutex_lock+0x76/0x940
mutex_lock_nested+0x1b/0x20
btrfs_qgroup_inherit+0x40/0x620 [btrfs]
create_pending_snapshot+0x9d7/0xe60 [btrfs]
create_pending_snapshots+0x94/0xb0 [btrfs]
btrfs_commit_transaction+0x415/0xa00 [btrfs]
btrfs_mksubvol+0x496/0x4e0 [btrfs]
btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs]
btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs]
btrfs_ioctl+0xa90/0x2b40 [btrfs]
do_vfs_ioctl+0xa9/0x6d0
ksys_ioctl+0x67/0x90
__x64_sys_ioctl+0x1a/0x20
do_syscall_64+0x65/0x240
entry_SYSCALL_64_after_hwframe+0x49/0xbe
other info that might help us debug this:
Chain exists of:
&fs_info->qgroup_ioctl_lock#2 --> &fs_info->reloc_mutex --> &fs_info->tree_log_mutex
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&fs_info->tree_log_mutex);
lock(&fs_info->reloc_mutex);
lock(&fs_info->tree_log_mutex);
lock(&fs_info->qgroup_ioctl_lock#2);
*** DEADLOCK ***
6 locks held by btrfs/8631:
#0: 00000000ed8f23f6 (sb_writers#12){.+.+}, at: mnt_want_write_file+0x28/0x60
#1: 000000009fb1597a (&type->i_mutex_dir_key#10/1){+.+.}, at: btrfs_mksubvol+0x70/0x4e0 [btrfs]
#2: 0000000088c5ad88 (&fs_info->subvol_sem){++++}, at: btrfs_mksubvol+0x128/0x4e0 [btrfs]
#3: 000000009606fc3e (sb_internal#2){.+.+}, at: start_transaction+0x37a/0x520 [btrfs]
#4: 00000000f82bbdf5 (&fs_info->reloc_mutex){+.+.}, at: btrfs_commit_transaction+0x40d/0xa00 [btrfs]
#5: 000000003d52cc23 (&fs_info->tree_log_mutex){+.+.}, at: create_pending_snapshot+0x8b6/0xe60 [btrfs]
[CAUSE]
Due to the delayed subvolume creation, we need to call
btrfs_qgroup_inherit() inside commit transaction code, with a lot of
other mutex hold.
This hell of lock chain can lead to above problem.
[FIX]
On the other hand, we don't really need to hold qgroup_ioctl_lock if
we're in the context of create_pending_snapshot().
As in that context, we're the only one being able to modify qgroup.
All other qgroup functions which needs qgroup_ioctl_lock are either
holding a transaction handle, or will start a new transaction:
Functions will start a new transaction():
* btrfs_quota_enable()
* btrfs_quota_disable()
Functions hold a transaction handler:
* btrfs_add_qgroup_relation()
* btrfs_del_qgroup_relation()
* btrfs_create_qgroup()
* btrfs_remove_qgroup()
* btrfs_limit_qgroup()
* btrfs_qgroup_inherit() call inside create_subvol()
So we have a higher level protection provided by transaction, thus we
don't need to always hold qgroup_ioctl_lock in btrfs_qgroup_inherit().
Only the btrfs_qgroup_inherit() call in create_subvol() needs to hold
qgroup_ioctl_lock, while the btrfs_qgroup_inherit() call in
create_pending_snapshot() is already protected by transaction.
So the fix is to detect the context by checking
trans->transaction->state.
If we're at TRANS_STATE_COMMIT_DOING, then we're in commit transaction
context and no need to get the mutex.
Reported-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 0ee5f8ae08 ]
The list of profiles in btrfs_chunk_max_errors lists DUP as a profile
DUP able to tolerate 1 device missing. Though this profile is special
with 2 copies, it still needs the device, unlike the others.
Looking at the history of changes, thre's no clear reason why DUP is
there, functions were refactored and blocks of code merged to one
helper.
d20983b40e Btrfs: fix writing data into the seed filesystem
- factor code to a helper
de11cc12df Btrfs: don't pre-allocate btrfs bio
- unrelated change, DUP still in the list with max errors 1
a236aed14c Btrfs: Deal with failed writes in mirrored configurations
- introduced the max errors, leaves DUP and RAID1 in the same group
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 42c16da6d6 upstream.
As btrfs(5) specified:
Note
If nodatacow or nodatasum are enabled, compression is disabled.
If NODATASUM or NODATACOW set, we should not compress the extent.
Normally NODATACOW is detected properly in run_delalloc_range() so
compression won't happen for NODATACOW.
However for NODATASUM we don't have any check, and it can cause
compressed extent without csum pretty easily, just by:
mkfs.btrfs -f $dev
mount $dev $mnt -o nodatasum
touch $mnt/foobar
mount -o remount,datasum,compress $mnt
xfs_io -f -c "pwrite 0 128K" $mnt/foobar
And in fact, we have a bug report about corrupted compressed extent
without proper data checksum so even RAID1 can't recover the corruption.
(https://bugzilla.kernel.org/show_bug.cgi?id=199707)
Running compression without proper checksum could cause more damage when
corruption happens, as compressed data could make the whole extent
unreadable, so there is no need to allow compression for
NODATACSUM.
The fix will refactor the inode compression check into two parts:
- inode_can_compress()
As the hard requirement, checked at btrfs_run_delalloc_range(), so no
compression will happen for NODATASUM inode at all.
- inode_need_compress()
As the soft requirement, checked at btrfs_run_delalloc_range() and
compress_file_range().
Reported-by: James Harvey <jamespharvey20@gmail.com>
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 179006688a upstream.
If the range for which we are punching a hole covers only part of a page,
we end up updating the inode item but we skip the update of the inode's
iversion, mtime and ctime. Fix that by ensuring we update those properties
of the inode.
A patch for fstests test case generic/059 that tests this as been sent
along with this fix.
Fixes: 2aaa665581 ("Btrfs: add hole punching")
Fixes: e8c1c76e80 ("Btrfs: add missing inode update when punching hole")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 803f0f64d1 upstream.
In order to avoid searches on a log tree when unlinking an inode, we check
if the inode being unlinked was logged in the current transaction, as well
as the inode of its parent directory. When any of the inodes are logged,
we proceed to delete directory items and inode reference items from the
log, to ensure that if a subsequent fsync of only the inode being unlinked
or only of the parent directory when the other is not fsync'ed as well,
does not result in the entry still existing after a power failure.
That check however is not reliable when one of the inodes involved (the
one being unlinked or its parent directory's inode) is evicted, since the
logged_trans field is transient, that is, it is not stored on disk, so it
is lost when the inode is evicted and loaded into memory again (which is
set to zero on load). As a consequence the checks currently being done by
btrfs_del_dir_entries_in_log() and btrfs_del_inode_ref_in_log() always
return true if the inode was evicted before, regardless of the inode
having been logged or not before (and in the current transaction), this
results in the dentry being unlinked still existing after a log replay
if after the unlink operation only one of the inodes involved is fsync'ed.
Example:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ mkdir /mnt/dir
$ touch /mnt/dir/foo
$ xfs_io -c fsync /mnt/dir/foo
# Keep an open file descriptor on our directory while we evict inodes.
# We just want to evict the file's inode, the directory's inode must not
# be evicted.
$ ( cd /mnt/dir; while true; do :; done ) &
$ pid=$!
# Wait a bit to give time to background process to chdir to our test
# directory.
$ sleep 0.5
# Trigger eviction of the file's inode.
$ echo 2 > /proc/sys/vm/drop_caches
# Unlink our file and fsync the parent directory. After a power failure
# we don't expect to see the file anymore, since we fsync'ed the parent
# directory.
$ rm -f $SCRATCH_MNT/dir/foo
$ xfs_io -c fsync /mnt/dir
<power failure>
$ mount /dev/sdb /mnt
$ ls /mnt/dir
foo
$
--> file still there, unlink not persisted despite explicit fsync on dir
Fix this by checking if the inode has the full_sync bit set in its runtime
flags as well, since that bit is set everytime an inode is loaded from
disk, or for other less common cases such as after a shrinking truncate
or failure to allocate extent maps for holes, and gets cleared after the
first fsync. Also consider the inode as possibly logged only if it was
last modified in the current transaction (besides having the full_fsync
flag set).
Fixes: 3a5f1d458a ("Btrfs: Optimize btree walking while logging inodes")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit d1d832a0b5 upstream.
When we log an inode, regardless of logging it completely or only that it
exists, we always update it as logged (logged_trans and last_log_commit
fields of the inode are updated). This is generally fine and avoids future
attempts to log it from having to do repeated work that brings no value.
However, if we write data to a file, then evict its inode after all the
dealloc was flushed (and ordered extents completed), rename the file and
fsync it, we end up not logging the new extents, since the rename may
result in logging that the inode exists in case the parent directory was
logged before. The following reproducer shows and explains how this can
happen:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ mkdir /mnt/dir
$ touch /mnt/dir/foo
$ touch /mnt/dir/bar
# Do a direct IO write instead of a buffered write because with a
# buffered write we would need to make sure dealloc gets flushed and
# complete before we do the inode eviction later, and we can not do that
# from user space with call to things such as sync(2) since that results
# in a transaction commit as well.
$ xfs_io -d -c "pwrite -S 0xd3 0 4K" /mnt/dir/bar
# Keep the directory dir in use while we evict inodes. We want our file
# bar's inode to be evicted but we don't want our directory's inode to
# be evicted (if it were evicted too, we would not be able to reproduce
# the issue since the first fsync below, of file foo, would result in a
# transaction commit.
$ ( cd /mnt/dir; while true; do :; done ) &
$ pid=$!
# Wait a bit to give time for the background process to chdir.
$ sleep 0.1
# Evict all inodes, except the inode for the directory dir because it is
# currently in use by our background process.
$ echo 2 > /proc/sys/vm/drop_caches
# fsync file foo, which ends up persisting information about the parent
# directory because it is a new inode.
$ xfs_io -c fsync /mnt/dir/foo
# Rename bar, this results in logging that this inode exists (inode item,
# names, xattrs) because the parent directory is in the log.
$ mv /mnt/dir/bar /mnt/dir/baz
# Now fsync baz, which ends up doing absolutely nothing because of the
# rename operation which logged that the inode exists only.
$ xfs_io -c fsync /mnt/dir/baz
<power failure>
$ mount /dev/sdb /mnt
$ od -t x1 -A d /mnt/dir/baz
0000000
--> Empty file, data we wrote is missing.
Fix this by not updating last_sub_trans of an inode when we are logging
only that it exists and the inode was not yet logged since it was loaded
from disk (full_sync bit set), this is enough to make btrfs_inode_in_log()
return false for this scenario and make us log the inode. The logged_trans
of the inode is still always setsince that alone is used to track if names
need to be deleted as part of unlink operations.
Fixes: 257c62e1bc ("Btrfs: avoid tree log commit when there are no changes")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit debd1c065d upstream.
Recent FITRIM work, namely bbbf7243d6 ("btrfs: combine device update
operations during transaction commit") combined the way certain
operations are recoded in a transaction. As a result an ASSERT was added
in dev_replace_finish to ensure the new code works correctly.
Unfortunately I got reports that it's possible to trigger the assert,
meaning that during a device replace it's possible to have an unfinished
chunk allocation on the source device.
This is supposed to be prevented by the fact that a transaction is
committed before finishing the replace oepration and alter acquiring the
chunk mutex. This is not sufficient since by the time the transaction is
committed and the chunk mutex acquired it's possible to allocate a chunk
depending on the workload being executed on the replaced device. This
bug has been present ever since device replace was introduced but there
was never code which checks for it.
The correct way to fix is to ensure that there is no pending device
modification operation when the chunk mutex is acquire and if there is
repeat transaction commit. Unfortunately it's not possible to just
exclude the source device from btrfs_fs_devices::dev_alloc_list since
this causes ENOSPC to be hit in transaction commit.
Fixing that in another way would need to add special cases to handle the
last writes and forbid new ones. The looped transaction fix is more
obvious, and can be easily backported. The runtime of dev-replace is
long so there's no noticeable delay caused by that.
Reported-by: David Sterba <dsterba@suse.com>
Fixes: 391cd9df81 ("Btrfs: fix unprotected alloc list insertion during the finishing procedure of replace")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c4e0540d0a upstream.
Currently, btrfs does not consult seed devices to start readahead. As a
result, if readahead zone is added to the seed devices, btrfs_reada_wait()
indefinitely wait for the reada_ctl to finish.
You can reproduce the hung by modifying btrfs/163 to have larger initial
file size (e.g. xfs_io pwrite 4M instead of current 256K).
Fixes: 7414a03fbf ("btrfs: initial readahead code and prototypes")
Cc: stable@vger.kernel.org # 3.2+: ce7791ffee: Btrfs: fix race between readahead and device replace/removal
Cc: stable@vger.kernel.org # 3.2+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6b1f72e5b8 upstream.
When using the no-holes feature, if we have a file with prealloc extents
with a start offset beyond the file's eof, doing an incremental send can
cause corruption of the file due to incorrect hole detection. Such case
requires that the prealloc extent(s) exist in both the parent and send
snapshots, and that a hole is punched into the file that covers all its
extents that do not cross the eof boundary.
Example reproducer:
$ mkfs.btrfs -f -O no-holes /dev/sdb
$ mount /dev/sdb /mnt/sdb
$ xfs_io -f -c "pwrite -S 0xab 0 500K" /mnt/sdb/foobar
$ xfs_io -c "falloc -k 1200K 800K" /mnt/sdb/foobar
$ btrfs subvolume snapshot -r /mnt/sdb /mnt/sdb/base
$ btrfs send -f /tmp/base.snap /mnt/sdb/base
$ xfs_io -c "fpunch 0 500K" /mnt/sdb/foobar
$ btrfs subvolume snapshot -r /mnt/sdb /mnt/sdb/incr
$ btrfs send -p /mnt/sdb/base -f /tmp/incr.snap /mnt/sdb/incr
$ md5sum /mnt/sdb/incr/foobar
816df6f64deba63b029ca19d880ee10a /mnt/sdb/incr/foobar
$ mkfs.btrfs -f /dev/sdc
$ mount /dev/sdc /mnt/sdc
$ btrfs receive -f /tmp/base.snap /mnt/sdc
$ btrfs receive -f /tmp/incr.snap /mnt/sdc
$ md5sum /mnt/sdc/incr/foobar
cf2ef71f4a9e90c2f6013ba3b2257ed2 /mnt/sdc/incr/foobar
--> Different checksum, because the prealloc extent beyond the
file's eof confused the hole detection code and it assumed
a hole starting at offset 0 and ending at the offset of the
prealloc extent (1200Kb) instead of ending at the offset
500Kb (the file's size).
Fix this by ensuring we never cross the file's size when issuing the
write operations for a hole.
Fixes: 16e7549f04 ("Btrfs: incompatible format change to remove hole extents")
CC: stable@vger.kernel.org # 3.14+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 60d9f50308 upstream.
While logging an inode we follow its ancestors and for each one we mark
it as logged in the current transaction, even if we have not logged it.
As a consequence if we change an attribute of an ancestor, such as the
UID or GID for example, and then explicitly fsync it, we end up not
logging the inode at all despite returning success to user space, which
results in the attribute being lost if a power failure happens after
the fsync.
Sample reproducer:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ mkdir /mnt/dir
$ chown 6007:6007 /mnt/dir
$ sync
$ chown 9003:9003 /mnt/dir
$ touch /mnt/dir/file
$ xfs_io -c fsync /mnt/dir/file
# fsync our directory after fsync'ing the new file, should persist the
# new values for the uid and gid.
$ xfs_io -c fsync /mnt/dir
<power failure>
$ mount /dev/sdb /mnt
$ stat -c %u:%g /mnt/dir
6007:6007
--> should be 9003:9003, the uid and gid were not persisted, despite
the explicit fsync on the directory prior to the power failure
Fix this by not updating the logged_trans field of ancestor inodes when
logging an inode, since we have not logged them. Let only future calls to
btrfs_log_inode() to mark inodes as logged.
This could be triggered by my recent fsync fuzz tester for fstests, for
which an fstests patch exists titled "fstests: generic, fsync fuzz tester
with fsstress".
Fixes: 12fcfd22fe ("Btrfs: tree logging unlink/rename fixes")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 06989c799f upstream.
When syncing the log, the final phase of a fsync operation, we need to
either create a log root's item or update the existing item in the log
tree of log roots, and that depends on the current value of the log
root's log_transid - if it's 1 we need to create the log root item,
otherwise it must exist already and we update it. Since there is no
synchronization between updating the log_transid and checking it for
deciding whether the log root's item needs to be created or updated, we
end up with a tiny race window that results in attempts to update the
item to fail because the item was not yet created:
CPU 1 CPU 2
btrfs_sync_log()
lock root->log_mutex
set log root's log_transid to 1
unlock root->log_mutex
btrfs_sync_log()
lock root->log_mutex
sets log root's
log_transid to 2
unlock root->log_mutex
update_log_root()
sees log root's log_transid
with a value of 2
calls btrfs_update_root(),
which fails with -EUCLEAN
and causes transaction abort
Until recently the race lead to a BUG_ON at btrfs_update_root(), but after
the recent commit 7ac1e464c4 ("btrfs: Don't panic when we can't find a
root key") we just abort the current transaction.
A sample trace of the BUG_ON() on a SLE12 kernel:
------------[ cut here ]------------
kernel BUG at ../fs/btrfs/root-tree.c:157!
Oops: Exception in kernel mode, sig: 5 [#1]
SMP NR_CPUS=2048 NUMA pSeries
(...)
Supported: Yes, External
CPU: 78 PID: 76303 Comm: rtas_errd Tainted: G X 4.4.156-94.57-default #1
task: c00000ffa906d010 ti: c00000ff42b08000 task.ti: c00000ff42b08000
NIP: d000000036ae5cdc LR: d000000036ae5cd8 CTR: 0000000000000000
REGS: c00000ff42b0b860 TRAP: 0700 Tainted: G X (4.4.156-94.57-default)
MSR: 8000000002029033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR: 22444484 XER: 20000000
CFAR: d000000036aba66c SOFTE: 1
GPR00: d000000036ae5cd8 c00000ff42b0bae0 d000000036bda220 0000000000000054
GPR04: 0000000000000001 0000000000000000 c00007ffff8d37c8 0000000000000000
GPR08: c000000000e19c00 0000000000000000 0000000000000000 3736343438312079
GPR12: 3930373337303434 c000000007a3a800 00000000007fffff 0000000000000023
GPR16: c00000ffa9d26028 c00000ffa9d261f8 0000000000000010 c00000ffa9d2ab28
GPR20: c00000ff42b0bc48 0000000000000001 c00000ff9f0d9888 0000000000000001
GPR24: c00000ffa9d26000 c00000ffa9d261e8 c00000ffa9d2a800 c00000ff9f0d9888
GPR28: c00000ffa9d26028 c00000ffa9d2aa98 0000000000000001 c00000ffa98f5b20
NIP [d000000036ae5cdc] btrfs_update_root+0x25c/0x4e0 [btrfs]
LR [d000000036ae5cd8] btrfs_update_root+0x258/0x4e0 [btrfs]
Call Trace:
[c00000ff42b0bae0] [d000000036ae5cd8] btrfs_update_root+0x258/0x4e0 [btrfs] (unreliable)
[c00000ff42b0bba0] [d000000036b53610] btrfs_sync_log+0x2d0/0xc60 [btrfs]
[c00000ff42b0bce0] [d000000036b1785c] btrfs_sync_file+0x44c/0x4e0 [btrfs]
[c00000ff42b0bd80] [c00000000032e300] vfs_fsync_range+0x70/0x120
[c00000ff42b0bdd0] [c00000000032e44c] do_fsync+0x5c/0xb0
[c00000ff42b0be10] [c00000000032e8dc] SyS_fdatasync+0x2c/0x40
[c00000ff42b0be30] [c000000000009488] system_call+0x3c/0x100
Instruction dump:
7f43d378 4bffebb9 60000000 88d90008 3d220000 e8b90000 3b390009 e87a01f0
e8898e08 e8f90000 4bfd48e5 60000000 <0fe00000> e95b0060 39200004 394a0ea0
---[ end trace 8f2dc8f919cabab8 ]---
So fix this by doing the check of log_transid and updating or creating the
log root's item while holding the root's log_mutex.
Fixes: 7237f18336 ("Btrfs: fix tree logs parallel sync")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 5338e43abb upstream.
When replaying a log that contains a new file or directory name that needs
to be added to its parent directory, we end up updating the mtime and the
ctime of the parent directory to the current time after we have set their
values to the correct ones (set at fsync time), efectivelly losing them.
Sample reproducer:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ mkdir /mnt/dir
$ touch /mnt/dir/file
# fsync of the directory is optional, not needed
$ xfs_io -c fsync /mnt/dir
$ xfs_io -c fsync /mnt/dir/file
$ stat -c %Y /mnt/dir
1557856079
<power failure>
$ sleep 3
$ mount /dev/sdb /mnt
$ stat -c %Y /mnt/dir
1557856082
--> should have been 1557856079, the mtime is updated to the current
time when replaying the log
Fix this by not updating the mtime and ctime to the current time at
btrfs_add_link() when we are replaying a log tree.
This could be triggered by my recent fsync fuzz tester for fstests, for
which an fstests patch exists titled "fstests: generic, fsync fuzz tester
with fsstress".
Fixes: e02119d5a7 ("Btrfs: Add a write ahead tree log to optimize synchronous operations")
CC: stable@vger.kernel.org # 4.4+
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 7ac1e464c4 ]
When we failed to find a root key in btrfs_update_root(), we just panic.
That's definitely not cool, fix it by outputting an unique error
message, aborting current transaction and return -EUCLEAN. This should
not normally happen as the root has been used by the callers in some
way.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ff612ba784 ]
We've been seeing the following sporadically throughout our fleet
panic: kernel BUG at fs/btrfs/relocation.c:4584!
netversion: 5.0-0
Backtrace:
#0 [ffffc90003adb880] machine_kexec at ffffffff81041da8
#1 [ffffc90003adb8c8] __crash_kexec at ffffffff8110396c
#2 [ffffc90003adb988] crash_kexec at ffffffff811048ad
#3 [ffffc90003adb9a0] oops_end at ffffffff8101c19a
#4 [ffffc90003adb9c0] do_trap at ffffffff81019114
#5 [ffffc90003adba00] do_error_trap at ffffffff810195d0
#6 [ffffc90003adbab0] invalid_op at ffffffff81a00a9b
[exception RIP: btrfs_reloc_cow_block+692]
RIP: ffffffff8143b614 RSP: ffffc90003adbb68 RFLAGS: 00010246
RAX: fffffffffffffff7 RBX: ffff8806b9c32000 RCX: ffff8806aad00690
RDX: ffff880850b295e0 RSI: ffff8806b9c32000 RDI: ffff88084f205bd0
RBP: ffff880849415000 R8: ffffc90003adbbe0 R9: ffff88085ac90000
R10: ffff8805f7369140 R11: 0000000000000000 R12: ffff880850b295e0
R13: ffff88084f205bd0 R14: 0000000000000000 R15: 0000000000000000
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#7 [ffffc90003adbbb0] __btrfs_cow_block at ffffffff813bf1cd
#8 [ffffc90003adbc28] btrfs_cow_block at ffffffff813bf4b3
#9 [ffffc90003adbc78] btrfs_search_slot at ffffffff813c2e6c
The way relocation moves data extents is by creating a reloc inode and
preallocating extents in this inode and then copying the data into these
preallocated extents. Once we've done this for all of our extents,
we'll write out these dirty pages, which marks the extent written, and
goes into btrfs_reloc_cow_block(). From here we get our current
reloc_control, which _should_ match the reloc_control for the current
block group we're relocating.
However if we get an ENOSPC in this path at some point we'll bail out,
never initiating writeback on this inode. Not a huge deal, unless we
happen to be doing relocation on a different block group, and this block
group is now rc->stage == UPDATE_DATA_PTRS. This trips the BUG_ON() in
btrfs_reloc_cow_block(), because we expect to be done modifying the data
inode. We are in fact done modifying the metadata for the data inode
we're currently using, but not the one from the failed block group, and
thus we BUG_ON().
(This happens when writeback finishes for extents from the previous
group, when we are at btrfs_finish_ordered_io() which updates the data
reloc tree (inode item, drops/adds extent items, etc).)
Fix this by writing out the reloc data inode always, and then breaking
out of the loop after that point to keep from tripping this BUG_ON()
later.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
[ add note from Filipe ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 39ad317315 ]
When doing fallocate, we first add the range to the reserve_list and
then reserve the quota. If quota reservation fails, we'll release all
reserved parts of reserve_list.
However, cur_offset is not updated to indicate that this range is
already been inserted into the list. Therefore, the same range is freed
twice. Once at list_for_each_entry loop, and once at the end of the
function. This will result in WARN_ON on bytes_may_use when we free the
remaining space.
At the end, under the 'out' label we have a call to:
btrfs_free_reserved_data_space(inode, data_reserved, alloc_start, alloc_end - cur_offset);
The start offset, third argument, should be cur_offset.
Everything from alloc_start to cur_offset was freed by the
list_for_each_entry_safe_loop.
Fixes: 18513091af ("btrfs: update btrfs_space_info's bytes_may_use timely")
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Robbie Ko <robbieko@synology.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This reverts commit 8b13bb911f.
There is currently no corresponding patch in master due to additional
changes that would be significantly different from plain revert in the
respective stable branch.
The range argument was not handled correctly and could cause trim to
overlap allocated areas or reach beyond the end of the device. The
address space that fitrim normally operates on is in logical
coordinates, while the discards are done on the physical device extents.
This distinction cannot be made with the current ioctl interface and
caused the confusion.
The bug depends on the layout of block groups and does not always
happen. The whole-fs trim (run by default by the fstrim tool) is not
affected.
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 38e3eebff6 upstream.
Qgroups will do the old roots lookup at delayed ref time, which could be
while walking down the extent root while running a delayed ref. This
should be fine, except we specifically lock eb's in the backref walking
code irrespective of path->skip_locking, which deadlocks the system.
Fix up the backref code to honor path->skip_locking, nobody will be
modifying the commit_root when we're searching so it's completely safe
to do.
This happens since fb235dc06f ("btrfs: qgroup: Move half of the qgroup
accounting time out of commit trans"), kernel may lockup with quota
enabled.
There is one backref trace triggered by snapshot dropping along with
write operation in the source subvolume. The example can be reliably
reproduced:
btrfs-cleaner D 0 4062 2 0x80000000
Call Trace:
schedule+0x32/0x90
btrfs_tree_read_lock+0x93/0x130 [btrfs]
find_parent_nodes+0x29b/0x1170 [btrfs]
btrfs_find_all_roots_safe+0xa8/0x120 [btrfs]
btrfs_find_all_roots+0x57/0x70 [btrfs]
btrfs_qgroup_trace_extent_post+0x37/0x70 [btrfs]
btrfs_qgroup_trace_leaf_items+0x10b/0x140 [btrfs]
btrfs_qgroup_trace_subtree+0xc8/0xe0 [btrfs]
do_walk_down+0x541/0x5e3 [btrfs]
walk_down_tree+0xab/0xe7 [btrfs]
btrfs_drop_snapshot+0x356/0x71a [btrfs]
btrfs_clean_one_deleted_snapshot+0xb8/0xf0 [btrfs]
cleaner_kthread+0x12b/0x160 [btrfs]
kthread+0x112/0x130
ret_from_fork+0x27/0x50
When dropping snapshots with qgroup enabled, we will trigger backref
walk.
However such backref walk at that timing is pretty dangerous, as if one
of the parent nodes get WRITE locked by other thread, we could cause a
dead lock.
For example:
FS 260 FS 261 (Dropped)
node A node B
/ \ / \
node C node D node E
/ \ / \ / \
leaf F|leaf G|leaf H|leaf I|leaf J|leaf K
The lock sequence would be:
Thread A (cleaner) | Thread B (other writer)
-----------------------------------------------------------------------
write_lock(B) |
write_lock(D) |
^^^ called by walk_down_tree() |
| write_lock(A)
| write_lock(D) << Stall
read_lock(H) << for backref walk |
read_lock(D) << lock owner is |
the same thread A |
so read lock is OK |
read_lock(A) << Stall |
So thread A hold write lock D, and needs read lock A to unlock.
While thread B holds write lock A, while needs lock D to unlock.
This will cause a deadlock.
This is not only limited to snapshot dropping case. As the backref
walk, even only happens on commit trees, is breaking the normal top-down
locking order, makes it deadlock prone.
Fixes: fb235dc06f ("btrfs: qgroup: Move half of the qgroup accounting time out of commit trans")
CC: stable@vger.kernel.org # 4.14+
Reported-and-tested-by: David Sterba <dsterba@suse.com>
Reported-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
[ rebase to latest branch and fix lock assert bug in btrfs/007 ]
[ backport to linux-4.19.y branch, solve minor conflicts ]
Signed-off-by: Qu Wenruo <wqu@suse.com>
[ copy logs and deadlock analysis from Qu's patch ]
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e32773357d upstream.
A failed call to kobject_init_and_add() must be followed by a call to
kobject_put(). Currently in the error path when adding fs_devices we
are missing this call. This could be fixed by calling
btrfs_sysfs_remove_fsid() if btrfs_sysfs_add_fsid() returns an error or
by adding a call to kobject_put() directly in btrfs_sysfs_add_fsid().
Here we choose the second option because it prevents the slightly
unusual error path handling requirements of kobject from leaking out
into btrfs functions.
Add a call to kobject_put() in the error path of kobject_add_and_init().
This causes the release method to be called if kobject_init_and_add()
fails. open_tree() is the function that calls btrfs_sysfs_add_fsid()
and the error code in this function is already written with the
assumption that the release method is called during the error path of
open_tree() (as seen by the call to btrfs_sysfs_remove_fsid() under the
fail_fsdev_sysfs label).
Cc: stable@vger.kernel.org # v4.4+
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tobin C. Harding <tobin@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 450ff83488 upstream.
If a call to kobject_init_and_add() fails we must call kobject_put()
otherwise we leak memory.
Calling kobject_put() when kobject_init_and_add() fails drops the
refcount back to 0 and calls the ktype release method (which in turn
calls the percpu destroy and kfree).
Add call to kobject_put() in the error path of call to
kobject_init_and_add().
Cc: stable@vger.kernel.org # v4.4+
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tobin C. Harding <tobin@kernel.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 0c713cbab6 upstream.
When we do a full fsync (the bit BTRFS_INODE_NEEDS_FULL_SYNC is set in the
inode) that happens to be ranged, which happens during a msync() or writes
for files opened with O_SYNC for example, we can end up with a corrupt log,
due to different file extent items representing ranges that overlap with
each other, or hit some assertion failures.
When doing a ranged fsync we only flush delalloc and wait for ordered
exents within that range. If while we are logging items from our inode
ordered extents for adjacent ranges complete, we end up in a race that can
make us insert the file extent items that overlap with others we logged
previously and the assertion failures.
For example, if tree-log.c:copy_items() receives a leaf that has the
following file extents items, all with a length of 4K and therefore there
is an implicit hole in the range 68K to 72K - 1:
(257 EXTENT_ITEM 64K), (257 EXTENT_ITEM 72K), (257 EXTENT_ITEM 76K), ...
It copies them to the log tree. However due to the need to detect implicit
holes, it may release the path, in order to look at the previous leaf to
detect an implicit hole, and then later it will search again in the tree
for the first file extent item key, with the goal of locking again the
leaf (which might have changed due to concurrent changes to other inodes).
However when it locks again the leaf containing the first key, the key
corresponding to the extent at offset 72K may not be there anymore since
there is an ordered extent for that range that is finishing (that is,
somewhere in the middle of btrfs_finish_ordered_io()), and it just
removed the file extent item but has not yet replaced it with a new file
extent item, so the part of copy_items() that does hole detection will
decide that there is a hole in the range starting from 68K to 76K - 1,
and therefore insert a file extent item to represent that hole, having
a key offset of 68K. After that we now have a log tree with 2 different
extent items that have overlapping ranges:
1) The file extent item copied before copy_items() released the path,
which has a key offset of 72K and a length of 4K, representing the
file range 72K to 76K - 1.
2) And a file extent item representing a hole that has a key offset of
68K and a length of 8K, representing the range 68K to 76K - 1. This
item was inserted after releasing the path, and overlaps with the
extent item inserted before.
The overlapping extent items can cause all sorts of unpredictable and
incorrect behaviour, either when replayed or if a fast (non full) fsync
happens later, which can trigger a BUG_ON() when calling
btrfs_set_item_key_safe() through __btrfs_drop_extents(), producing a
trace like the following:
[61666.783269] ------------[ cut here ]------------
[61666.783943] kernel BUG at fs/btrfs/ctree.c:3182!
[61666.784644] invalid opcode: 0000 [#1] PREEMPT SMP
(...)
[61666.786253] task: ffff880117b88c40 task.stack: ffffc90008168000
[61666.786253] RIP: 0010:btrfs_set_item_key_safe+0x7c/0xd2 [btrfs]
[61666.786253] RSP: 0018:ffffc9000816b958 EFLAGS: 00010246
[61666.786253] RAX: 0000000000000000 RBX: 000000000000000f RCX: 0000000000030000
[61666.786253] RDX: 0000000000000000 RSI: ffffc9000816ba4f RDI: ffffc9000816b937
[61666.786253] RBP: ffffc9000816b998 R08: ffff88011dae2428 R09: 0000000000001000
[61666.786253] R10: 0000160000000000 R11: 6db6db6db6db6db7 R12: ffff88011dae2418
[61666.786253] R13: ffffc9000816ba4f R14: ffff8801e10c4118 R15: ffff8801e715c000
[61666.786253] FS: 00007f6060a18700(0000) GS:ffff88023f5c0000(0000) knlGS:0000000000000000
[61666.786253] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[61666.786253] CR2: 00007f6060a28000 CR3: 0000000213e69000 CR4: 00000000000006e0
[61666.786253] Call Trace:
[61666.786253] __btrfs_drop_extents+0x5e3/0xaad [btrfs]
[61666.786253] ? time_hardirqs_on+0x9/0x14
[61666.786253] btrfs_log_changed_extents+0x294/0x4e0 [btrfs]
[61666.786253] ? release_extent_buffer+0x38/0xb4 [btrfs]
[61666.786253] btrfs_log_inode+0xb6e/0xcdc [btrfs]
[61666.786253] ? lock_acquire+0x131/0x1c5
[61666.786253] ? btrfs_log_inode_parent+0xee/0x659 [btrfs]
[61666.786253] ? arch_local_irq_save+0x9/0xc
[61666.786253] ? btrfs_log_inode_parent+0x1f5/0x659 [btrfs]
[61666.786253] btrfs_log_inode_parent+0x223/0x659 [btrfs]
[61666.786253] ? arch_local_irq_save+0x9/0xc
[61666.786253] ? lockref_get_not_zero+0x2c/0x34
[61666.786253] ? rcu_read_unlock+0x3e/0x5d
[61666.786253] btrfs_log_dentry_safe+0x60/0x7b [btrfs]
[61666.786253] btrfs_sync_file+0x317/0x42c [btrfs]
[61666.786253] vfs_fsync_range+0x8c/0x9e
[61666.786253] SyS_msync+0x13c/0x1c9
[61666.786253] entry_SYSCALL_64_fastpath+0x18/0xad
A sample of a corrupt log tree leaf with overlapping extents I got from
running btrfs/072:
item 14 key (295 108 200704) itemoff 2599 itemsize 53
extent data disk bytenr 0 nr 0
extent data offset 0 nr 458752 ram 458752
item 15 key (295 108 659456) itemoff 2546 itemsize 53
extent data disk bytenr 4343541760 nr 770048
extent data offset 606208 nr 163840 ram 770048
item 16 key (295 108 663552) itemoff 2493 itemsize 53
extent data disk bytenr 4343541760 nr 770048
extent data offset 610304 nr 155648 ram 770048
item 17 key (295 108 819200) itemoff 2440 itemsize 53
extent data disk bytenr 4334788608 nr 4096
extent data offset 0 nr 4096 ram 4096
The file extent item at offset 659456 (item 15) ends at offset 823296
(659456 + 163840) while the next file extent item (item 16) starts at
offset 663552.
Another different problem that the race can trigger is a failure in the
assertions at tree-log.c:copy_items(), which expect that the first file
extent item key we found before releasing the path exists after we have
released path and that the last key we found before releasing the path
also exists after releasing the path:
$ cat -n fs/btrfs/tree-log.c
4080 if (need_find_last_extent) {
4081 /* btrfs_prev_leaf could return 1 without releasing the path */
4082 btrfs_release_path(src_path);
4083 ret = btrfs_search_slot(NULL, inode->root, &first_key,
4084 src_path, 0, 0);
4085 if (ret < 0)
4086 return ret;
4087 ASSERT(ret == 0);
(...)
4103 if (i >= btrfs_header_nritems(src_path->nodes[0])) {
4104 ret = btrfs_next_leaf(inode->root, src_path);
4105 if (ret < 0)
4106 return ret;
4107 ASSERT(ret == 0);
4108 src = src_path->nodes[0];
4109 i = 0;
4110 need_find_last_extent = true;
4111 }
(...)
The second assertion implicitly expects that the last key before the path
release still exists, because the surrounding while loop only stops after
we have found that key. When this assertion fails it produces a stack like
this:
[139590.037075] assertion failed: ret == 0, file: fs/btrfs/tree-log.c, line: 4107
[139590.037406] ------------[ cut here ]------------
[139590.037707] kernel BUG at fs/btrfs/ctree.h:3546!
[139590.038034] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI
[139590.038340] CPU: 1 PID: 31841 Comm: fsstress Tainted: G W 5.0.0-btrfs-next-46 #1
(...)
[139590.039354] RIP: 0010:assfail.constprop.24+0x18/0x1a [btrfs]
(...)
[139590.040397] RSP: 0018:ffffa27f48f2b9b0 EFLAGS: 00010282
[139590.040730] RAX: 0000000000000041 RBX: ffff897c635d92c8 RCX: 0000000000000000
[139590.041105] RDX: 0000000000000000 RSI: ffff897d36a96868 RDI: ffff897d36a96868
[139590.041470] RBP: ffff897d1b9a0708 R08: 0000000000000000 R09: 0000000000000000
[139590.041815] R10: 0000000000000008 R11: 0000000000000000 R12: 0000000000000013
[139590.042159] R13: 0000000000000227 R14: ffff897cffcbba88 R15: 0000000000000001
[139590.042501] FS: 00007f2efc8dee80(0000) GS:ffff897d36a80000(0000) knlGS:0000000000000000
[139590.042847] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[139590.043199] CR2: 00007f8c064935e0 CR3: 0000000232252002 CR4: 00000000003606e0
[139590.043547] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[139590.043899] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[139590.044250] Call Trace:
[139590.044631] copy_items+0xa3f/0x1000 [btrfs]
[139590.045009] ? generic_bin_search.constprop.32+0x61/0x200 [btrfs]
[139590.045396] btrfs_log_inode+0x7b3/0xd70 [btrfs]
[139590.045773] btrfs_log_inode_parent+0x2b3/0xce0 [btrfs]
[139590.046143] ? do_raw_spin_unlock+0x49/0xc0
[139590.046510] btrfs_log_dentry_safe+0x4a/0x70 [btrfs]
[139590.046872] btrfs_sync_file+0x3b6/0x440 [btrfs]
[139590.047243] btrfs_file_write_iter+0x45b/0x5c0 [btrfs]
[139590.047592] __vfs_write+0x129/0x1c0
[139590.047932] vfs_write+0xc2/0x1b0
[139590.048270] ksys_write+0x55/0xc0
[139590.048608] do_syscall_64+0x60/0x1b0
[139590.048946] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[139590.049287] RIP: 0033:0x7f2efc4be190
(...)
[139590.050342] RSP: 002b:00007ffe743243a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[139590.050701] RAX: ffffffffffffffda RBX: 0000000000008d58 RCX: 00007f2efc4be190
[139590.051067] RDX: 0000000000008d58 RSI: 00005567eca0f370 RDI: 0000000000000003
[139590.051459] RBP: 0000000000000024 R08: 0000000000000003 R09: 0000000000008d60
[139590.051863] R10: 0000000000000078 R11: 0000000000000246 R12: 0000000000000003
[139590.052252] R13: 00000000003d3507 R14: 00005567eca0f370 R15: 0000000000000000
(...)
[139590.055128] ---[ end trace 193f35d0215cdeeb ]---
So fix this race between a full ranged fsync and writeback of adjacent
ranges by flushing all delalloc and waiting for all ordered extents to
complete before logging the inode. This is the simplest way to solve the
problem because currently the full fsync path does not deal with ranges
at all (it assumes a full range from 0 to LLONG_MAX) and it always needs
to look at adjacent ranges for hole detection. For use cases of ranged
fsyncs this can make a few fsyncs slower but on the other hand it can
make some following fsyncs to other ranges do less work or no need to do
anything at all. A full fsync is rare anyway and happens only once after
loading/creating an inode and once after less common operations such as a
shrinking truncate.
This is an issue that exists for a long time, and was often triggered by
generic/127, because it does mmap'ed writes and msync (which triggers a
ranged fsync). Adding support for the tree checker to detect overlapping
extents (next patch in the series) and trigger a WARN() when such cases
are found, and then calling btrfs_check_leaf_full() at the end of
btrfs_insert_file_extent() made the issue much easier to detect. Running
btrfs/072 with that change to the tree checker and making fsstress open
files always with O_SYNC made it much easier to trigger the issue (as
triggering it with generic/127 is very rare).
CC: stable@vger.kernel.org # 3.16+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ebb929060a upstream.
When we are doing a full fsync (bit BTRFS_INODE_NEEDS_FULL_SYNC set) of a
file that has holes and has file extent items spanning two or more leafs,
we can end up falling to back to a full transaction commit due to a logic
bug that leads to failure to insert a duplicate file extent item that is
meant to represent a hole between the last file extent item of a leaf and
the first file extent item in the next leaf. The failure (EEXIST error)
leads to a transaction commit (as most errors when logging an inode do).
For example, we have the two following leafs:
Leaf N:
-----------------------------------------------
| ..., ..., ..., (257, FILE_EXTENT_ITEM, 64K) |
-----------------------------------------------
The file extent item at the end of leaf N has a length of 4Kb,
representing the file range from 64K to 68K - 1.
Leaf N + 1:
-----------------------------------------------
| (257, FILE_EXTENT_ITEM, 72K), ..., ..., ... |
-----------------------------------------------
The file extent item at the first slot of leaf N + 1 has a length of
4Kb too, representing the file range from 72K to 76K - 1.
During the full fsync path, when we are at tree-log.c:copy_items() with
leaf N as a parameter, after processing the last file extent item, that
represents the extent at offset 64K, we take a look at the first file
extent item at the next leaf (leaf N + 1), and notice there's a 4K hole
between the two extents, and therefore we insert a file extent item
representing that hole, starting at file offset 68K and ending at offset
72K - 1. However we don't update the value of *last_extent, which is used
to represent the end offset (plus 1, non-inclusive end) of the last file
extent item inserted in the log, so it stays with a value of 68K and not
with a value of 72K.
Then, when copy_items() is called for leaf N + 1, because the value of
*last_extent is smaller then the offset of the first extent item in the
leaf (68K < 72K), we look at the last file extent item in the previous
leaf (leaf N) and see it there's a 4K gap between it and our first file
extent item (again, 68K < 72K), so we decide to insert a file extent item
representing the hole, starting at file offset 68K and ending at offset
72K - 1, this insertion will fail with -EEXIST being returned from
btrfs_insert_file_extent() because we already inserted a file extent item
representing a hole for this offset (68K) in the previous call to
copy_items(), when processing leaf N.
The -EEXIST error gets propagated to the fsync callback, btrfs_sync_file(),
which falls back to a full transaction commit.
Fix this by adjusting *last_extent after inserting a hole when we had to
look at the next leaf.
Fixes: 4ee3fad34a ("Btrfs: fix fsync after hole punching when using no-holes feature")
Cc: stable@vger.kernel.org # 4.14+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 72bd2323ec upstream.
Currently when we fail to COW a path at btrfs_update_root() we end up
always aborting the transaction. However all the current callers of
btrfs_update_root() are able to deal with errors returned from it, many do
end up aborting the transaction themselves (directly or not, such as the
transaction commit path), other BUG_ON() or just gracefully cancel whatever
they were doing.
When syncing the fsync log, we call btrfs_update_root() through
tree-log.c:update_log_root(), and if it returns an -ENOSPC error, the log
sync code does not abort the transaction, instead it gracefully handles
the error and returns -EAGAIN to the fsync handler, so that it falls back
to a transaction commit. Any other error different from -ENOSPC, makes the
log sync code abort the transaction.
So remove the transaction abort from btrfs_update_log() when we fail to
COW a path to update the root item, so that if an -ENOSPC failure happens
we avoid aborting the current transaction and have a chance of the fsync
succeeding after falling back to a transaction commit.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203413
Fixes: 79787eaab4 ("btrfs: replace many BUG_ONs with proper error handling")
Cc: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 8fca955057 upstream.
If we have an error writing out a delalloc range in
btrfs_punch_hole_lock_range we'll unlock the inode and then goto
out_only_mutex, where we will again unlock the inode. This is bad,
don't do this.
Fixes: f27451f229 ("Btrfs: add support for fallocate's zero range operation")
CC: stable@vger.kernel.org # 4.19+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit bfc61c3626 upstream.
When finding out which inodes have references on a particular extent, done
by backref.c:iterate_extent_inodes(), from the BTRFS_IOC_LOGICAL_INO (both
v1 and v2) ioctl and from scrub we use the transaction join API to grab a
reference on the currently running transaction, since in order to give
accurate results we need to inspect the delayed references of the currently
running transaction.
However, if there is currently no running transaction, the join operation
will create a new transaction. This is inefficient as the transaction will
eventually be committed, doing unnecessary IO and introducing a potential
point of failure that will lead to a transaction abort due to -ENOSPC, as
recently reported [1].
That's because the join, creates the transaction but does not reserve any
space, so when attempting to update the root item of the root passed to
btrfs_join_transaction(), during the transaction commit, we can end up
failling with -ENOSPC. Users of a join operation are supposed to actually
do some filesystem changes and reserve space by some means, which is not
the case of iterate_extent_inodes(), it is a read-only operation for all
contextes from which it is called.
The reported [1] -ENOSPC failure stack trace is the following:
heisenberg kernel: ------------[ cut here ]------------
heisenberg kernel: BTRFS: Transaction aborted (error -28)
heisenberg kernel: WARNING: CPU: 0 PID: 7137 at fs/btrfs/root-tree.c:136 btrfs_update_root+0x22b/0x320 [btrfs]
(...)
heisenberg kernel: CPU: 0 PID: 7137 Comm: btrfs-transacti Not tainted 4.19.0-4-amd64 #1 Debian 4.19.28-2
heisenberg kernel: Hardware name: FUJITSU LIFEBOOK U757/FJNB2A5, BIOS Version 1.21 03/19/2018
heisenberg kernel: RIP: 0010:btrfs_update_root+0x22b/0x320 [btrfs]
(...)
heisenberg kernel: RSP: 0018:ffffb5448828bd40 EFLAGS: 00010286
heisenberg kernel: RAX: 0000000000000000 RBX: ffff8ed56bccef50 RCX: 0000000000000006
heisenberg kernel: RDX: 0000000000000007 RSI: 0000000000000092 RDI: ffff8ed6bda166a0
heisenberg kernel: RBP: 00000000ffffffe4 R08: 00000000000003df R09: 0000000000000007
heisenberg kernel: R10: 0000000000000000 R11: 0000000000000001 R12: ffff8ed63396a078
heisenberg kernel: R13: ffff8ed092d7c800 R14: ffff8ed64f5db028 R15: ffff8ed6bd03d068
heisenberg kernel: FS: 0000000000000000(0000) GS:ffff8ed6bda00000(0000) knlGS:0000000000000000
heisenberg kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
heisenberg kernel: CR2: 00007f46f75f8000 CR3: 0000000310a0a002 CR4: 00000000003606f0
heisenberg kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
heisenberg kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
heisenberg kernel: Call Trace:
heisenberg kernel: commit_fs_roots+0x166/0x1d0 [btrfs]
heisenberg kernel: ? _cond_resched+0x15/0x30
heisenberg kernel: ? btrfs_run_delayed_refs+0xac/0x180 [btrfs]
heisenberg kernel: btrfs_commit_transaction+0x2bd/0x870 [btrfs]
heisenberg kernel: ? start_transaction+0x9d/0x3f0 [btrfs]
heisenberg kernel: transaction_kthread+0x147/0x180 [btrfs]
heisenberg kernel: ? btrfs_cleanup_transaction+0x530/0x530 [btrfs]
heisenberg kernel: kthread+0x112/0x130
heisenberg kernel: ? kthread_bind+0x30/0x30
heisenberg kernel: ret_from_fork+0x35/0x40
heisenberg kernel: ---[ end trace 05de912e30e012d9 ]---
So fix that by using the attach API, which does not create a transaction
when there is currently no running transaction.
[1] https://lore.kernel.org/linux-btrfs/b2a668d7124f1d3e410367f587926f622b3f03a4.camel@scientia.net/
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 03628cdbc6 upstream.
During fiemap, for regular extents (non inline) we need to check if they
are shared and if they are, set the shared bit. Checking if an extent is
shared requires checking the delayed references of the currently running
transaction, since some reference might have not yet hit the extent tree
and be only in the in-memory delayed references.
However we were using a transaction join for this, which creates a new
transaction when there is no transaction currently running. That means
that two more potential failures can happen: creating the transaction and
committing it. Further, if no write activity is currently happening in the
system, and fiemap calls keep being done, we end up creating and
committing transactions that do nothing.
In some extreme cases this can result in the commit of the transaction
created by fiemap to fail with ENOSPC when updating the root item of a
subvolume tree because a join does not reserve any space, leading to a
trace like the following:
heisenberg kernel: ------------[ cut here ]------------
heisenberg kernel: BTRFS: Transaction aborted (error -28)
heisenberg kernel: WARNING: CPU: 0 PID: 7137 at fs/btrfs/root-tree.c:136 btrfs_update_root+0x22b/0x320 [btrfs]
(...)
heisenberg kernel: CPU: 0 PID: 7137 Comm: btrfs-transacti Not tainted 4.19.0-4-amd64 #1 Debian 4.19.28-2
heisenberg kernel: Hardware name: FUJITSU LIFEBOOK U757/FJNB2A5, BIOS Version 1.21 03/19/2018
heisenberg kernel: RIP: 0010:btrfs_update_root+0x22b/0x320 [btrfs]
(...)
heisenberg kernel: RSP: 0018:ffffb5448828bd40 EFLAGS: 00010286
heisenberg kernel: RAX: 0000000000000000 RBX: ffff8ed56bccef50 RCX: 0000000000000006
heisenberg kernel: RDX: 0000000000000007 RSI: 0000000000000092 RDI: ffff8ed6bda166a0
heisenberg kernel: RBP: 00000000ffffffe4 R08: 00000000000003df R09: 0000000000000007
heisenberg kernel: R10: 0000000000000000 R11: 0000000000000001 R12: ffff8ed63396a078
heisenberg kernel: R13: ffff8ed092d7c800 R14: ffff8ed64f5db028 R15: ffff8ed6bd03d068
heisenberg kernel: FS: 0000000000000000(0000) GS:ffff8ed6bda00000(0000) knlGS:0000000000000000
heisenberg kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
heisenberg kernel: CR2: 00007f46f75f8000 CR3: 0000000310a0a002 CR4: 00000000003606f0
heisenberg kernel: DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
heisenberg kernel: DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
heisenberg kernel: Call Trace:
heisenberg kernel: commit_fs_roots+0x166/0x1d0 [btrfs]
heisenberg kernel: ? _cond_resched+0x15/0x30
heisenberg kernel: ? btrfs_run_delayed_refs+0xac/0x180 [btrfs]
heisenberg kernel: btrfs_commit_transaction+0x2bd/0x870 [btrfs]
heisenberg kernel: ? start_transaction+0x9d/0x3f0 [btrfs]
heisenberg kernel: transaction_kthread+0x147/0x180 [btrfs]
heisenberg kernel: ? btrfs_cleanup_transaction+0x530/0x530 [btrfs]
heisenberg kernel: kthread+0x112/0x130
heisenberg kernel: ? kthread_bind+0x30/0x30
heisenberg kernel: ret_from_fork+0x35/0x40
heisenberg kernel: ---[ end trace 05de912e30e012d9 ]---
Since fiemap (and btrfs_check_shared()) is a read-only operation, do not do
a transaction join to avoid the overhead of creating a new transaction (if
there is currently no running transaction) and introducing a potential
point of failure when the new transaction gets committed, instead use a
transaction attach to grab a handle for the currently running transaction
if any.
Reported-by: Christoph Anton Mitterer <calestyo@scientia.net>
Link: https://lore.kernel.org/linux-btrfs/b2a668d7124f1d3e410367f587926f622b3f03a4.camel@scientia.net/
Fixes: afce772e87 ("btrfs: fix check_shared for fiemap ioctl")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9f89d5de86 upstream.
When we set a subvolume to read-only mode we do not flush dellaloc for any
of its inodes (except if the filesystem is mounted with -o flushoncommit),
since it does not affect correctness for any subsequent operations - except
for a future send operation. The send operation will not be able to see the
delalloc data since the respective file extent items, inode item updates,
backreferences, etc, have not hit yet the subvolume and extent trees.
Effectively this means data loss, since the send stream will not contain
any data from existing delalloc. Another problem from this is that if the
writeback starts and finishes while the send operation is in progress, we
have the subvolume tree being being modified concurrently which can result
in send failing unexpectedly with EIO or hitting runtime errors, assertion
failures or hitting BUG_ONs, etc.
Simple reproducer:
$ mkfs.btrfs -f /dev/sdb
$ mount /dev/sdb /mnt
$ btrfs subvolume create /mnt/sv
$ xfs_io -f -c "pwrite -S 0xea 0 108K" /mnt/sv/foo
$ btrfs property set /mnt/sv ro true
$ btrfs send -f /tmp/send.stream /mnt/sv
$ od -t x1 -A d /mnt/sv/foo
0000000 ea ea ea ea ea ea ea ea ea ea ea ea ea ea ea ea
*
0110592
$ umount /mnt
$ mkfs.btrfs -f /dev/sdc
$ mount /dev/sdc /mnt
$ btrfs receive -f /tmp/send.stream /mnt
$ echo $?
0
$ od -t x1 -A d /mnt/sv/foo
0000000
# ---> empty file
Since this a problem that affects send only, fix it in send by flushing
dellaloc for all the roots used by the send operation before send starts
to process the commit roots.
This is a problem that affects send since it was introduced (commit
31db9f7c23 ("Btrfs: introduce BTRFS_IOC_SEND for btrfs send/receive"))
but backporting it to older kernels has some dependencies:
- For kernels between 3.19 and 4.20, it depends on commit 3cd24c6980
("btrfs: use tagged writepage to mitigate livelock of snapshot") because
the function btrfs_start_delalloc_snapshot() does not exist before that
commit. So one has to either pick that commit or replace the calls to
btrfs_start_delalloc_snapshot() in this patch with calls to
btrfs_start_delalloc_inodes().
- For kernels older than 3.19 it also requires commit e5fa8f865b
("Btrfs: ensure send always works on roots without orphans") because
it depends on the function ensure_commit_roots_uptodate() which that
commits introduced.
- No dependencies for 5.0+ kernels.
A test case for fstests follows soon.
CC: stable@vger.kernel.org # 3.19+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit c2d1b3aae3 upstream.
Up until now trimming the freespace was done irrespective of what the
arguments of the FITRIM ioctl were. For example fstrim's -o/-l arguments
will be entirely ignored. Fix it by correctly handling those paramter.
This requires breaking if the found freespace extent is after the end of
the passed range as well as completing trim after trimming
fstrim_range::len bytes.
Fixes: 499f377f49 ("btrfs: iterate over unused chunk space in FITRIM")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Filipe Manana