Commit Graph

11585 Commits

Author SHA1 Message Date
Qu Wenruo
0391c9085a btrfs: do not wait for short bulk allocation
commit 1db7959aac upstream.

[BUG]
There is a recent report that when memory pressure is high (including
cached pages), btrfs can spend most of its time on memory allocation in
btrfs_alloc_page_array() for compressed read/write.

[CAUSE]
For btrfs_alloc_page_array() we always go alloc_pages_bulk_array(), and
even if the bulk allocation failed (fell back to single page
allocation) we still retry but with extra memalloc_retry_wait().

If the bulk alloc only returned one page a time, we would spend a lot of
time on the retry wait.

The behavior was introduced in commit 395cb57e85 ("btrfs: wait between
incomplete batch memory allocations").

[FIX]
Although the commit mentioned that other filesystems do the wait, it's
not the case at least nowadays.

All the mainlined filesystems only call memalloc_retry_wait() if they
failed to allocate any page (not only for bulk allocation).
If there is any progress, they won't call memalloc_retry_wait() at all.

For example, xfs_buf_alloc_pages() would only call memalloc_retry_wait()
if there is no allocation progress at all, and the call is not for
metadata readahead.

So I don't believe we should call memalloc_retry_wait() unconditionally
for short allocation.

Call memalloc_retry_wait() if it fails to allocate any page for tree
block allocation (which goes with __GFP_NOFAIL and may not need the
special handling anyway), and reduce the latency for
btrfs_alloc_page_array().

Reported-by: Julian Taylor <julian.taylor@1und1.de>
Tested-by: Julian Taylor <julian.taylor@1und1.de>
Link: https://lore.kernel.org/all/8966c095-cbe7-4d22-9784-a647d1bf27c3@1und1.de/
Fixes: 395cb57e85 ("btrfs: wait between incomplete batch memory allocations")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
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>
2024-05-17 11:56:23 +02:00
Dominique Martinet
25090e9bb0 btrfs: add missing mutex_unlock in btrfs_relocate_sys_chunks()
commit 9af503d912 upstream.

The previous patch that replaced BUG_ON by error handling forgot to
unlock the mutex in the error path.

Link: https://lore.kernel.org/all/Zh%2fHpAGFqa7YAFuM@duo.ucw.cz
Reported-by: Pavel Machek <pavel@denx.de>
Fixes: 7411055db5 ("btrfs: handle chunk tree lookup error in btrfs_relocate_sys_chunks()")
CC: stable@vger.kernel.org
Reviewed-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.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>
2024-05-17 11:56:19 +02:00
Dmitry Antipov
53f2bfce46 btrfs: fix kvcalloc() arguments order in btrfs_ioctl_send()
commit 6ff09b6b8c upstream.

When compiling with gcc version 14.0.0 20231220 (experimental)
and W=1, I've noticed the following warning:

fs/btrfs/send.c: In function 'btrfs_ioctl_send':
fs/btrfs/send.c:8208:44: warning: 'kvcalloc' sizes specified with 'sizeof'
in the earlier argument and not in the later argument [-Wcalloc-transposed-args]
 8208 |         sctx->clone_roots = kvcalloc(sizeof(*sctx->clone_roots),
      |                                            ^

Since 'n' and 'size' arguments of 'kvcalloc()' are multiplied to
calculate the final size, their actual order doesn't affect the result
and so this is not a bug. But it's still worth to fix it.

Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-05-17 11:56:16 +02:00
Boris Burkov
e04539f513 btrfs: always clear PERTRANS metadata during commit
[ Upstream commit 6e68de0bb0 ]

It is possible to clear a root's IN_TRANS tag from the radix tree, but
not clear its PERTRANS, if there is some error in between. Eliminate
that possibility by moving the free up to where we clear the tag.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 11:56:06 +02:00
Boris Burkov
66619d8ad3 btrfs: make btrfs_clear_delalloc_extent() free delalloc reserve
[ Upstream commit 3c6f0c5ecc ]

Currently, this call site in btrfs_clear_delalloc_extent() only converts
the reservation. We are marking it not delalloc, so I don't think it
makes sense to keep the rsv around.  This is a path where we are not
sure to join a transaction, so it leads to incorrect free-ing during
umount.

Helps with the pass rate of generic/269 and generic/475.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 11:56:06 +02:00
Anand Jain
681fb3c25d btrfs: return accurate error code on open failure in open_fs_devices()
[ Upstream commit 2f1aeab9fc ]

When attempting to exclusive open a device which has no exclusive open
permission, such as a physical device associated with the flakey dm
device, the open operation will fail, resulting in a mount failure.

In this particular scenario, we erroneously return -EINVAL instead of the
correct error code provided by the bdev_open_by_path() function, which is
-EBUSY.

Fix this, by returning error code from the bdev_open_by_path() function.
With this correction, the mount error message will align with that of
ext4 and xfs.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-05-17 11:56:04 +02:00
Johannes Thumshirn
8bdbcfaf3e btrfs: fix information leak in btrfs_ioctl_logical_to_ino()
commit 2f7ef5bb4a upstream.

Syzbot reported the following information leak for in
btrfs_ioctl_logical_to_ino():

  BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline]
  BUG: KMSAN: kernel-infoleak in _copy_to_user+0xbc/0x110 lib/usercopy.c:40
   instrument_copy_to_user include/linux/instrumented.h:114 [inline]
   _copy_to_user+0xbc/0x110 lib/usercopy.c:40
   copy_to_user include/linux/uaccess.h:191 [inline]
   btrfs_ioctl_logical_to_ino+0x440/0x750 fs/btrfs/ioctl.c:3499
   btrfs_ioctl+0x714/0x1260
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:904 [inline]
   __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
   __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
   x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
   do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

  Uninit was created at:
   __kmalloc_large_node+0x231/0x370 mm/slub.c:3921
   __do_kmalloc_node mm/slub.c:3954 [inline]
   __kmalloc_node+0xb07/0x1060 mm/slub.c:3973
   kmalloc_node include/linux/slab.h:648 [inline]
   kvmalloc_node+0xc0/0x2d0 mm/util.c:634
   kvmalloc include/linux/slab.h:766 [inline]
   init_data_container+0x49/0x1e0 fs/btrfs/backref.c:2779
   btrfs_ioctl_logical_to_ino+0x17c/0x750 fs/btrfs/ioctl.c:3480
   btrfs_ioctl+0x714/0x1260
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:904 [inline]
   __se_sys_ioctl+0x261/0x450 fs/ioctl.c:890
   __x64_sys_ioctl+0x96/0xe0 fs/ioctl.c:890
   x64_sys_call+0x1883/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:17
   do_syscall_x64 arch/x86/entry/common.c:52 [inline]
   do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

  Bytes 40-65535 of 65536 are uninitialized
  Memory access of size 65536 starts at ffff888045a40000

This happens, because we're copying a 'struct btrfs_data_container' back
to user-space. This btrfs_data_container is allocated in
'init_data_container()' via kvmalloc(), which does not zero-fill the
memory.

Fix this by using kvzalloc() which zeroes out the memory on allocation.

CC: stable@vger.kernel.org # 4.14+
Reported-by:  <syzbot+510a1abbb8116eeb341d@syzkaller.appspotmail.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <Johannes.thumshirn@wdc.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>
2024-05-02 16:29:28 +02:00
Boris Burkov
c00146b399 btrfs: qgroup: convert PREALLOC to PERTRANS after record_root_in_trans
commit 211de93367 upstream.

The transaction is only able to free PERTRANS reservations for a root
once that root has been recorded with the TRANS tag on the roots radix
tree. Therefore, until we are sure that this root will get tagged, it
isn't safe to convert. Generally, this is not an issue as *some*
transaction will likely tag the root before long and this reservation
will get freed in that transaction, but technically it could stick
around until unmount and result in a warning about leaked metadata
reservation space.

This path is most exercised by running the generic/269 fstest with
CONFIG_BTRFS_DEBUG.

Fixes: a649684967 ("btrfs: fix start transaction qgroup rsv double free")
CC: stable@vger.kernel.org # 6.6+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-17 11:18:26 +02:00
Boris Burkov
06fe999854 btrfs: record delayed inode root in transaction
commit 71537e35c3 upstream.

When running delayed inode updates, we do not record the inode's root in
the transaction, but we do allocate PREALLOC and thus converted PERTRANS
space for it. To be sure we free that PERTRANS meta rsv, we must ensure
that we record the root in the transaction.

Fixes: 4f5427ccce ("btrfs: delayed-inode: Use new qgroup meta rsv for delayed inode and item")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-17 11:18:26 +02:00
Boris Burkov
cb3131b5a2 btrfs: qgroup: correctly model root qgroup rsv in convert
commit 141fb8cd20 upstream.

We use add_root_meta_rsv and sub_root_meta_rsv to track prealloc and
pertrans reservations for subvolumes when quotas are enabled. The
convert function does not properly increment pertrans after decrementing
prealloc, so the count is not accurate.

Note: we check that the fs is not read-only to mirror the logic in
qgroup_convert_meta, which checks that before adding to the pertrans rsv.

Fixes: 8287475a20 ("btrfs: qgroup: Use root::qgroup_meta_rsv_* to record qgroup meta reserved space")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-04-17 11:18:26 +02:00
David Sterba
9ae356c627 btrfs: send: handle path ref underflow in header iterate_inode_ref()
[ Upstream commit 3c6ee34c6f ]

Change BUG_ON to proper error handling if building the path buffer
fails. The pointers are not printed so we don't accidentally leak kernel
addresses.

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-13 13:05:01 +02:00
David Sterba
0f30f95b91 btrfs: export: handle invalid inode or root reference in btrfs_get_parent()
[ Upstream commit 26b66d1d36 ]

The get_parent handler looks up a parent of a given dentry, this can be
either a subvolume or a directory. The search is set up with offset -1
but it's never expected to find such item, as it would break allowed
range of inode number or a root id. This means it's a corruption (ext4
also returns this error code).

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-13 13:05:01 +02:00
David Sterba
36c2a2863b btrfs: handle chunk tree lookup error in btrfs_relocate_sys_chunks()
[ Upstream commit 7411055db5 ]

The unhandled case in btrfs_relocate_sys_chunks() loop is a corruption,
as it could be caused only by two impossible conditions:

- at first the search key is set up to look for a chunk tree item, with
  offset -1, this is an inexact search and the key->offset will contain
  the correct offset upon a successful search, a valid chunk tree item
  cannot have an offset -1

- after first successful search, the found_key corresponds to a chunk
  item, the offset is decremented by 1 before the next loop, it's
  impossible to find a chunk item there due to alignment and size
  constraints

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-04-13 13:05:00 +02:00
Johannes Thumshirn
d7387bcb77 btrfs: zoned: use zone aware sb location for scrub
commit 74098a989b upstream.

At the moment scrub_supers() doesn't grab the super block's location via
the zoned device aware btrfs_sb_log_location() but via btrfs_sb_offset().

This leads to checksum errors on 'scrub' as we're not accessing the
correct location of the super block.

So use btrfs_sb_log_location() for getting the super blocks location on
scrub.

Reported-by: WA AM <waautomata@gmail.com>
Link: http://lore.kernel.org/linux-btrfs/CANU2Z0EvUzfYxczLgGUiREoMndE9WdQnbaawV5Fv5gNXptPUKw@mail.gmail.com
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
2024-04-03 15:19:48 +02:00
Johannes Thumshirn
a321a9907c btrfs: zoned: don't skip block groups with 100% zone unusable
commit a8b70c7f86 upstream.

Commit f4a9f21941 ("btrfs: do not delete unused block group if it may be
used soon") changed the behaviour of deleting unused block-groups on zoned
filesystems. Starting with this commit, we're using
btrfs_space_info_used() to calculate the number of used bytes in a
space_info. But btrfs_space_info_used() also accounts
btrfs_space_info::bytes_zone_unusable as used bytes.

So if a block group is 100% zone_unusable it is skipped from the deletion
step.

In order not to skip fully zone_unusable block-groups, also check if the
block-group has bytes left that can be used on a zoned filesystem.

Fixes: f4a9f21941 ("btrfs: do not delete unused block group if it may be used soon")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
2024-04-03 15:19:48 +02:00
Filipe Manana
50361c2af7 btrfs: fix off-by-one chunk length calculation at contains_pending_extent()
[ Upstream commit ae6bd7f9b4 ]

At contains_pending_extent() the value of the end offset of a chunk we
found in the device's allocation state io tree is inclusive, so when
we calculate the length we pass to the in_range() macro, we must sum
1 to the expression "physical_end - physical_offset".

In practice the wrong calculation should be harmless as chunks sizes
are never 1 byte and we should never have 1 byte ranges of unallocated
space. Nevertheless fix the wrong calculation.

Reported-by: Alex Lyakas <alex.lyakas@zadara.com>
Link: https://lore.kernel.org/linux-btrfs/CAOcd+r30e-f4R-5x-S7sV22RJPe7+pgwherA6xqN2_qe7o4XTg@mail.gmail.com/
Fixes: 1c11b63eff ("btrfs: replace pending/pinned chunks lists with io tree")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
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: Sasha Levin <sashal@kernel.org>
2024-04-03 15:19:31 +02:00
Qu Wenruo
c13e725657 btrfs: qgroup: always free reserved space for extent records
[ Upstream commit d139ded8b9 ]

[BUG]
If qgroup is marked inconsistent (e.g. caused by operations needing full
subtree rescan, like creating a snapshot and assign to a higher level
qgroup), btrfs would immediately start leaking its data reserved space.

The following script can easily reproduce it:

  mkfs.btrfs -O quota -f $dev
  mount $dev $mnt
  btrfs subvolume create $mnt/subv1
  btrfs qgroup create 1/0 $mnt

  # This snapshot creation would mark qgroup inconsistent,
  # as the ownership involves different higher level qgroup, thus
  # we have to rescan both source and snapshot, which can be very
  # time consuming, thus here btrfs just choose to mark qgroup
  # inconsistent, and let users to determine when to do the rescan.
  btrfs subv snapshot -i 1/0 $mnt/subv1 $mnt/snap1

  # Now this write would lead to qgroup rsv leak.
  xfs_io -f -c "pwrite 0 64k" $mnt/file1

  # And at unmount time, btrfs would report 64K DATA rsv space leaked.
  umount $mnt

And we would have the following dmesg output for the unmount:

  BTRFS info (device dm-1): last unmount of filesystem 14a3d84e-f47b-4f72-b053-a8a36eef74d3
  BTRFS warning (device dm-1): qgroup 0/5 has unreleased space, type 0 rsv 65536

[CAUSE]
Since commit e15e9f43c7 ("btrfs: introduce
BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting"),
we introduce a mode for btrfs qgroup to skip the timing consuming
backref walk, if the qgroup is already inconsistent.

But this skip also covered the data reserved freeing, thus the qgroup
reserved space for each newly created data extent would not be freed,
thus cause the leakage.

[FIX]
Make the data extent reserved space freeing mandatory.

The qgroup reserved space handling is way cheaper compared to the
backref walking part, and we always have the super sensitive leak
detector, thus it's definitely worth to always free the qgroup
reserved data space.

Reported-by: Fabian Vogt <fvogt@suse.com>
Fixes: e15e9f43c7 ("btrfs: introduce BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING to skip qgroup accounting")
CC: stable@vger.kernel.org # 6.1+
Link: https://bugzilla.suse.com/show_bug.cgi?id=1216196
Reviewed-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>
2024-04-03 15:19:31 +02:00
Filipe Manana
ab1be3f1aa btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve
[ Upstream commit c7bb26b847 ]

At btrfs_use_block_rsv() we read the size of a block reserve without
locking its spinlock, which makes KCSAN complain because the size of a
block reserve is always updated while holding its spinlock. The report
from KCSAN is the following:

  [653.313148] BUG: KCSAN: data-race in btrfs_update_delayed_refs_rsv [btrfs] / btrfs_use_block_rsv [btrfs]

  [653.314755] read to 0x000000017f5871b8 of 8 bytes by task 7519 on cpu 0:
  [653.314779]  btrfs_use_block_rsv+0xe4/0x2f8 [btrfs]
  [653.315606]  btrfs_alloc_tree_block+0xdc/0x998 [btrfs]
  [653.316421]  btrfs_force_cow_block+0x220/0xe38 [btrfs]
  [653.317242]  btrfs_cow_block+0x1ac/0x568 [btrfs]
  [653.318060]  btrfs_search_slot+0xda2/0x19b8 [btrfs]
  [653.318879]  btrfs_del_csums+0x1dc/0x798 [btrfs]
  [653.319702]  __btrfs_free_extent.isra.0+0xc24/0x2028 [btrfs]
  [653.320538]  __btrfs_run_delayed_refs+0xd3c/0x2390 [btrfs]
  [653.321340]  btrfs_run_delayed_refs+0xae/0x290 [btrfs]
  [653.322140]  flush_space+0x5e4/0x718 [btrfs]
  [653.322958]  btrfs_preempt_reclaim_metadata_space+0x102/0x2f8 [btrfs]
  [653.323781]  process_one_work+0x3b6/0x838
  [653.323800]  worker_thread+0x75e/0xb10
  [653.323817]  kthread+0x21a/0x230
  [653.323836]  __ret_from_fork+0x6c/0xb8
  [653.323855]  ret_from_fork+0xa/0x30

  [653.323887] write to 0x000000017f5871b8 of 8 bytes by task 576 on cpu 3:
  [653.323906]  btrfs_update_delayed_refs_rsv+0x1a4/0x250 [btrfs]
  [653.324699]  btrfs_add_delayed_data_ref+0x468/0x6d8 [btrfs]
  [653.325494]  btrfs_free_extent+0x76/0x120 [btrfs]
  [653.326280]  __btrfs_mod_ref+0x6a8/0x6b8 [btrfs]
  [653.327064]  btrfs_dec_ref+0x50/0x70 [btrfs]
  [653.327849]  walk_up_proc+0x236/0xa50 [btrfs]
  [653.328633]  walk_up_tree+0x21c/0x448 [btrfs]
  [653.329418]  btrfs_drop_snapshot+0x802/0x1328 [btrfs]
  [653.330205]  btrfs_clean_one_deleted_snapshot+0x184/0x238 [btrfs]
  [653.330995]  cleaner_kthread+0x2b0/0x2f0 [btrfs]
  [653.331781]  kthread+0x21a/0x230
  [653.331800]  __ret_from_fork+0x6c/0xb8
  [653.331818]  ret_from_fork+0xa/0x30

So add a helper to get the size of a block reserve while holding the lock.
Reading the field while holding the lock instead of using the data_race()
annotation is used in order to prevent load tearing.

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>
2024-03-26 18:20:26 -04:00
Filipe Manana
995e91c955 btrfs: fix data races when accessing the reserved amount of block reserves
[ Upstream commit e06cc89475 ]

At space_info.c we have several places where we access the ->reserved
field of a block reserve without taking the block reserve's spinlock
first, which makes KCSAN warn about a data race since that field is
always updated while holding the spinlock.

The reports from KCSAN are like the following:

  [117.193526] BUG: KCSAN: data-race in btrfs_block_rsv_release [btrfs] / need_preemptive_reclaim [btrfs]

  [117.195148] read to 0x000000017f587190 of 8 bytes by task 6303 on cpu 3:
  [117.195172]  need_preemptive_reclaim+0x222/0x2f0 [btrfs]
  [117.195992]  __reserve_bytes+0xbb0/0xdc8 [btrfs]
  [117.196807]  btrfs_reserve_metadata_bytes+0x4c/0x120 [btrfs]
  [117.197620]  btrfs_block_rsv_add+0x78/0xa8 [btrfs]
  [117.198434]  btrfs_delayed_update_inode+0x154/0x368 [btrfs]
  [117.199300]  btrfs_update_inode+0x108/0x1c8 [btrfs]
  [117.200122]  btrfs_dirty_inode+0xb4/0x140 [btrfs]
  [117.200937]  btrfs_update_time+0x8c/0xb0 [btrfs]
  [117.201754]  touch_atime+0x16c/0x1e0
  [117.201789]  filemap_read+0x674/0x728
  [117.201823]  btrfs_file_read_iter+0xf8/0x410 [btrfs]
  [117.202653]  vfs_read+0x2b6/0x498
  [117.203454]  ksys_read+0xa2/0x150
  [117.203473]  __s390x_sys_read+0x68/0x88
  [117.203495]  do_syscall+0x1c6/0x210
  [117.203517]  __do_syscall+0xc8/0xf0
  [117.203539]  system_call+0x70/0x98

  [117.203579] write to 0x000000017f587190 of 8 bytes by task 11 on cpu 0:
  [117.203604]  btrfs_block_rsv_release+0x2e8/0x578 [btrfs]
  [117.204432]  btrfs_delayed_inode_release_metadata+0x7c/0x1d0 [btrfs]
  [117.205259]  __btrfs_update_delayed_inode+0x37c/0x5e0 [btrfs]
  [117.206093]  btrfs_async_run_delayed_root+0x356/0x498 [btrfs]
  [117.206917]  btrfs_work_helper+0x160/0x7a0 [btrfs]
  [117.207738]  process_one_work+0x3b6/0x838
  [117.207768]  worker_thread+0x75e/0xb10
  [117.207797]  kthread+0x21a/0x230
  [117.207830]  __ret_from_fork+0x6c/0xb8
  [117.207861]  ret_from_fork+0xa/0x30

So add a helper to get the reserved amount of a block reserve while
holding the lock. The value may be not be up to date anymore when used by
need_preemptive_reclaim() and btrfs_preempt_reclaim_metadata_space(), but
that's ok since the worst it can do is cause more reclaim work do be done
sooner rather than later. Reading the field while holding the lock instead
of using the data_race() annotation is used in order to prevent load
tearing.

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>
2024-03-26 18:20:26 -04:00
Filipe Manana
444d70889d btrfs: send: don't issue unnecessary zero writes for trailing hole
commit 5897710b28 upstream.

If we have a sparse file with a trailing hole (from the last extent's end
to i_size) and then create an extent in the file that ends before the
file's i_size, then when doing an incremental send we will issue a write
full of zeroes for the range that starts immediately after the new extent
ends up to i_size. While this isn't incorrect because the file ends up
with exactly the same data, it unnecessarily results in using extra space
at the destination with one or more extents full of zeroes instead of
having a hole. In same cases this results in using megabytes or even
gigabytes of unnecessary space.

Example, reproducer:

   $ cat test.sh
   #!/bin/bash

   DEV=/dev/sdh
   MNT=/mnt/sdh

   mkfs.btrfs -f $DEV
   mount $DEV $MNT

   # Create 1G sparse file.
   xfs_io -f -c "truncate 1G" $MNT/foobar

   # Create base snapshot.
   btrfs subvolume snapshot -r $MNT $MNT/mysnap1

   # Create send stream (full send) for the base snapshot.
   btrfs send -f /tmp/1.snap $MNT/mysnap1

   # Now write one extent at the beginning of the file and one somewhere
   # in the middle, leaving a gap between the end of this second extent
   # and the file's size.
   xfs_io -c "pwrite -S 0xab 0 128K" \
          -c "pwrite -S 0xcd 512M 128K" \
          $MNT/foobar

   # Now create a second snapshot which is going to be used for an
   # incremental send operation.
   btrfs subvolume snapshot -r $MNT $MNT/mysnap2

   # Create send stream (incremental send) for the second snapshot.
   btrfs send -p $MNT/mysnap1 -f /tmp/2.snap $MNT/mysnap2

   # Now recreate the filesystem by receiving both send streams and
   # verify we get the same content that the original filesystem had
   # and file foobar has only two extents with a size of 128K each.
   umount $MNT
   mkfs.btrfs -f $DEV
   mount $DEV $MNT

   btrfs receive -f /tmp/1.snap $MNT
   btrfs receive -f /tmp/2.snap $MNT

   echo -e "\nFile fiemap in the second snapshot:"
   # Should have:
   #
   # 128K extent at file range [0, 128K[
   # hole at file range [128K, 512M[
   # 128K extent file range [512M, 512M + 128K[
   # hole at file range [512M + 128K, 1G[
   xfs_io -r -c "fiemap -v" $MNT/mysnap2/foobar

   # File should be using 256K of data (two 128K extents).
   echo -e "\nSpace used by the file: $(du -h $MNT/mysnap2/foobar | cut -f 1)"

   umount $MNT

Running the test, we can see with fiemap that we get an extent for the
range [512M, 1G[, while in the source filesystem we have an extent for
the range [512M, 512M + 128K[ and a hole for the rest of the file (the
range [512M + 128K, 1G[):

   $ ./test.sh
   (...)
   File fiemap in the second snapshot:
   /mnt/sdh/mysnap2/foobar:
    EXT: FILE-OFFSET        BLOCK-RANGE        TOTAL FLAGS
      0: [0..255]:          26624..26879         256   0x0
      1: [256..1048575]:    hole             1048320
      2: [1048576..2097151]: 2156544..3205119 1048576   0x1

   Space used by the file: 513M

This happens because once we finish processing an inode, at
finish_inode_if_needed(), we always issue a hole (write operations full
of zeros) if there's a gap between the end of the last processed extent
and the file's size, even if that range is already a hole in the parent
snapshot. Fix this by issuing the hole only if the range is not already
a hole.

After this change, running the test above, we get the expected layout:

   $ ./test.sh
   (...)
   File fiemap in the second snapshot:
   /mnt/sdh/mysnap2/foobar:
    EXT: FILE-OFFSET        BLOCK-RANGE      TOTAL FLAGS
      0: [0..255]:          26624..26879       256   0x0
      1: [256..1048575]:    hole             1048320
      2: [1048576..1048831]: 26880..27135       256   0x1
      3: [1048832..2097151]: hole             1048320

   Space used by the file: 256K

A test case for fstests will follow soon.

CC: stable@vger.kernel.org # 6.1+
Reported-by: Dorai Ashok S A <dash.btrfs@inix.me>
Link: https://lore.kernel.org/linux-btrfs/c0bf7818-9c45-46a8-b3d3-513230d0c86e@inix.me/
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
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>
2024-03-06 14:45:10 +00:00
David Sterba
f590040ce2 btrfs: dev-replace: properly validate device names
commit 9845664b9e upstream.

There's a syzbot report that device name buffers passed to device
replace are not properly checked for string termination which could lead
to a read out of bounds in getname_kernel().

Add a helper that validates both source and target device name buffers.
For devid as the source initialize the buffer to empty string in case
something tries to read it later.

This was originally analyzed and fixed in a different way by Edward Adam
Davis (see links).

Link: https://lore.kernel.org/linux-btrfs/000000000000d1a1d1060cc9c5e7@google.com/
Link: https://lore.kernel.org/linux-btrfs/tencent_44CA0665C9836EF9EEC80CB9E7E206DF5206@qq.com/
CC: stable@vger.kernel.org # 4.19+
CC: Edward Adam Davis <eadavis@qq.com>
Reported-and-tested-by: syzbot+33f23b49ac24f986c9e8@syzkaller.appspotmail.com
Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-03-06 14:45:10 +00:00
Filipe Manana
c34adc20b9 btrfs: fix double free of anonymous device after snapshot creation failure
commit e2b54eaf28 upstream.

When creating a snapshot we may do a double free of an anonymous device
in case there's an error committing the transaction. The second free may
result in freeing an anonymous device number that was allocated by some
other subsystem in the kernel or another btrfs filesystem.

The steps that lead to this:

1) At ioctl.c:create_snapshot() we allocate an anonymous device number
   and assign it to pending_snapshot->anon_dev;

2) Then we call btrfs_commit_transaction() and end up at
   transaction.c:create_pending_snapshot();

3) There we call btrfs_get_new_fs_root() and pass it the anonymous device
   number stored in pending_snapshot->anon_dev;

4) btrfs_get_new_fs_root() frees that anonymous device number because
   btrfs_lookup_fs_root() returned a root - someone else did a lookup
   of the new root already, which could some task doing backref walking;

5) After that some error happens in the transaction commit path, and at
   ioctl.c:create_snapshot() we jump to the 'fail' label, and after
   that we free again the same anonymous device number, which in the
   meanwhile may have been reallocated somewhere else, because
   pending_snapshot->anon_dev still has the same value as in step 1.

Recently syzbot ran into this and reported the following trace:

  ------------[ cut here ]------------
  ida_free called for id=51 which is not allocated.
  WARNING: CPU: 1 PID: 31038 at lib/idr.c:525 ida_free+0x370/0x420 lib/idr.c:525
  Modules linked in:
  CPU: 1 PID: 31038 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-00410-gc02197fc9076 #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
  RIP: 0010:ida_free+0x370/0x420 lib/idr.c:525
  Code: 10 42 80 3c 28 (...)
  RSP: 0018:ffffc90015a67300 EFLAGS: 00010246
  RAX: be5130472f5dd000 RBX: 0000000000000033 RCX: 0000000000040000
  RDX: ffffc90009a7a000 RSI: 000000000003ffff RDI: 0000000000040000
  RBP: ffffc90015a673f0 R08: ffffffff81577992 R09: 1ffff92002b4cdb4
  R10: dffffc0000000000 R11: fffff52002b4cdb5 R12: 0000000000000246
  R13: dffffc0000000000 R14: ffffffff8e256b80 R15: 0000000000000246
  FS:  00007fca3f4b46c0(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f167a17b978 CR3: 000000001ed26000 CR4: 0000000000350ef0
  Call Trace:
   <TASK>
   btrfs_get_root_ref+0xa48/0xaf0 fs/btrfs/disk-io.c:1346
   create_pending_snapshot+0xff2/0x2bc0 fs/btrfs/transaction.c:1837
   create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1931
   btrfs_commit_transaction+0xf1c/0x3740 fs/btrfs/transaction.c:2404
   create_snapshot+0x507/0x880 fs/btrfs/ioctl.c:848
   btrfs_mksubvol+0x5d0/0x750 fs/btrfs/ioctl.c:998
   btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1044
   __btrfs_ioctl_snap_create+0x387/0x4b0 fs/btrfs/ioctl.c:1306
   btrfs_ioctl_snap_create_v2+0x1ca/0x400 fs/btrfs/ioctl.c:1393
   btrfs_ioctl+0xa74/0xd40
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:871 [inline]
   __se_sys_ioctl+0xfe/0x170 fs/ioctl.c:857
   do_syscall_64+0xfb/0x240
   entry_SYSCALL_64_after_hwframe+0x6f/0x77
  RIP: 0033:0x7fca3e67dda9
  Code: 28 00 00 00 (...)
  RSP: 002b:00007fca3f4b40c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 00007fca3e7abf80 RCX: 00007fca3e67dda9
  RDX: 00000000200005c0 RSI: 0000000050009417 RDI: 0000000000000003
  RBP: 00007fca3e6ca47a R08: 0000000000000000 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
  R13: 000000000000000b R14: 00007fca3e7abf80 R15: 00007fff6bf95658
   </TASK>

Where we get an explicit message where we attempt to free an anonymous
device number that is not currently allocated. It happens in a different
code path from the example below, at btrfs_get_root_ref(), so this change
may not fix the case triggered by syzbot.

To fix at least the code path from the example above, change
btrfs_get_root_ref() and its callers to receive a dev_t pointer argument
for the anonymous device number, so that in case it frees the number, it
also resets it to 0, so that up in the call chain we don't attempt to do
the double free.

CC: stable@vger.kernel.org # 5.10+
Link: https://lore.kernel.org/linux-btrfs/000000000000f673a1061202f630@google.com/
Fixes: e03ee2fe87 ("btrfs: do not ASSERT() if the newly created subvolume already got read")
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>
2024-03-06 14:45:10 +00:00
Josef Bacik
02f2b95b00 btrfs: don't drop extent_map for free space inode on write error
commit 5571e41ec6 upstream.

While running the CI for an unrelated change I hit the following panic
with generic/648 on btrfs_holes_spacecache.

assertion failed: block_start != EXTENT_MAP_HOLE, in fs/btrfs/extent_io.c:1385
------------[ cut here ]------------
kernel BUG at fs/btrfs/extent_io.c:1385!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 1 PID: 2695096 Comm: fsstress Kdump: loaded Tainted: G        W          6.8.0-rc2+ #1
RIP: 0010:__extent_writepage_io.constprop.0+0x4c1/0x5c0
Call Trace:
 <TASK>
 extent_write_cache_pages+0x2ac/0x8f0
 extent_writepages+0x87/0x110
 do_writepages+0xd5/0x1f0
 filemap_fdatawrite_wbc+0x63/0x90
 __filemap_fdatawrite_range+0x5c/0x80
 btrfs_fdatawrite_range+0x1f/0x50
 btrfs_write_out_cache+0x507/0x560
 btrfs_write_dirty_block_groups+0x32a/0x420
 commit_cowonly_roots+0x21b/0x290
 btrfs_commit_transaction+0x813/0x1360
 btrfs_sync_file+0x51a/0x640
 __x64_sys_fdatasync+0x52/0x90
 do_syscall_64+0x9c/0x190
 entry_SYSCALL_64_after_hwframe+0x6e/0x76

This happens because we fail to write out the free space cache in one
instance, come back around and attempt to write it again.  However on
the second pass through we go to call btrfs_get_extent() on the inode to
get the extent mapping.  Because this is a new block group, and with the
free space inode we always search the commit root to avoid deadlocking
with the tree, we find nothing and return a EXTENT_MAP_HOLE for the
requested range.

This happens because the first time we try to write the space cache out
we hit an error, and on an error we drop the extent mapping.  This is
normal for normal files, but the free space cache inode is special.  We
always expect the extent map to be correct.  Thus the second time
through we end up with a bogus extent map.

Since we're deprecating this feature, the most straightforward way to
fix this is to simply skip dropping the extent map range for this failed
range.

I shortened the test by using error injection to stress the area to make
it easier to reproduce.  With this patch in place we no longer panic
with my error injection test.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:29 +01:00
Filipe Manana
7ba7f9ed88 btrfs: reject encoded write if inode has nodatasum flag set
commit 1bd96c92c6 upstream.

Currently we allow an encoded write against inodes that have the NODATASUM
flag set, either because they are NOCOW files or they were created while
the filesystem was mounted with "-o nodatasum". This results in having
compressed extents without corresponding checksums, which is a filesystem
inconsistency reported by 'btrfs check'.

For example, running btrfs/281 with MOUNT_OPTIONS="-o nodatacow" triggers
this and 'btrfs check' errors out with:

   [1/7] checking root items
   [2/7] checking extents
   [3/7] checking free space tree
   [4/7] checking fs roots
   root 256 inode 257 errors 1040, bad file extent, some csum missing
   root 256 inode 258 errors 1040, bad file extent, some csum missing
   ERROR: errors found in fs roots
   (...)

So reject encoded writes if the target inode has NODATASUM set.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
2024-02-23 09:12:29 +01:00
Filipe Manana
4d6b2e17b5 btrfs: don't reserve space for checksums when writing to nocow files
commit feefe1f49d upstream.

Currently when doing a write to a file we always reserve metadata space
for inserting data checksums. However we don't need to do it if we have
a nodatacow file (-o nodatacow mount option or chattr +C) or if checksums
are disabled (-o nodatasum mount option), as in that case we are only
adding unnecessary pressure to metadata reservations.

For example on x86_64, with the default node size of 16K, a 4K buffered
write into a nodatacow file is reserving 655360 bytes of metadata space,
as it's accounting for checksums. After this change, which stops reserving
space for checksums if we have a nodatacow file or checksums are disabled,
we only need to reserve 393216 bytes of metadata.

CC: stable@vger.kernel.org # 6.1+
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>
2024-02-23 09:12:29 +01:00
David Sterba
dfd1f44e49 btrfs: send: return EOPNOTSUPP on unknown flags
commit f884a9f9e5 upstream.

When some ioctl flags are checked we return EOPNOTSUPP, like for
BTRFS_SCRUB_SUPPORTED_FLAGS, BTRFS_SUBVOL_CREATE_ARGS_MASK or fallocate
modes. The EINVAL is supposed to be for a supported but invalid
values or combination of options. Fix that when checking send flags so
it's consistent with the rest.

CC: stable@vger.kernel.org # 4.14+
Link: https://lore.kernel.org/linux-btrfs/CAL3q7H5rryOLzp3EKq8RTbjMHMHeaJubfpsVLF6H4qJnKCUR1w@mail.gmail.com/
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:29 +01:00
Boris Burkov
f98913c07c btrfs: forbid deleting live subvol qgroup
commit a8df356199 upstream.

If a subvolume still exists, forbid deleting its qgroup 0/subvolid.
This behavior generally leads to incorrect behavior in squotas and
doesn't have a legitimate purpose.

Fixes: cecbb533b5 ("btrfs: record simple quota deltas in delayed refs")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:29 +01:00
Qu Wenruo
66b317a2fc btrfs: do not ASSERT() if the newly created subvolume already got read
commit e03ee2fe87 upstream.

[BUG]
There is a syzbot crash, triggered by the ASSERT() during subvolume
creation:

 assertion failed: !anon_dev, in fs/btrfs/disk-io.c:1319
 ------------[ cut here ]------------
 kernel BUG at fs/btrfs/disk-io.c:1319!
 invalid opcode: 0000 [#1] PREEMPT SMP KASAN
 RIP: 0010:btrfs_get_root_ref.part.0+0x9aa/0xa60
  <TASK>
  btrfs_get_new_fs_root+0xd3/0xf0
  create_subvol+0xd02/0x1650
  btrfs_mksubvol+0xe95/0x12b0
  __btrfs_ioctl_snap_create+0x2f9/0x4f0
  btrfs_ioctl_snap_create+0x16b/0x200
  btrfs_ioctl+0x35f0/0x5cf0
  __x64_sys_ioctl+0x19d/0x210
  do_syscall_64+0x3f/0xe0
  entry_SYSCALL_64_after_hwframe+0x63/0x6b
 ---[ end trace 0000000000000000 ]---

[CAUSE]
During create_subvol(), after inserting root item for the newly created
subvolume, we would trigger btrfs_get_new_fs_root() to get the
btrfs_root of that subvolume.

The idea here is, we have preallocated an anonymous device number for
the subvolume, thus we can assign it to the new subvolume.

But there is really nothing preventing things like backref walk to read
the new subvolume.
If that happens before we call btrfs_get_new_fs_root(), the subvolume
would be read out, with a new anonymous device number assigned already.

In that case, we would trigger ASSERT(), as we really expect no one to
read out that subvolume (which is not yet accessible from the fs).
But things like backref walk is still possible to trigger the read on
the subvolume.

Thus our assumption on the ASSERT() is not correct in the first place.

[FIX]
Fix it by removing the ASSERT(), and just free the @anon_dev, reset it
to 0, and continue.

If the subvolume tree is read out by something else, it should have
already get a new anon_dev assigned thus we only need to free the
preallocated one.

Reported-by: Chenyuan Yang <chenyuan0y@gmail.com>
Fixes: 2dfb1e43f5 ("btrfs: preallocate anon block device at first phase of snapshot creation")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
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>
2024-02-23 09:12:29 +01:00
Boris Burkov
a1a7b95895 btrfs: forbid creating subvol qgroups
commit 0c309d66da upstream.

Creating a qgroup 0/subvolid leads to various races and it isn't
helpful, because you can't specify a subvol id when creating a subvol,
so you can't be sure it will be the right one. Any requirements on the
automatic subvol can be gratified by using a higher level qgroup and the
inheritance parameters of subvol creation.

Fixes: cecbb533b5 ("btrfs: record simple quota deltas in delayed refs")
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-02-23 09:12:28 +01:00
Filipe Manana
e717aecd2a btrfs: do not delete unused block group if it may be used soon
commit f4a9f21941 upstream.

Before deleting a block group that is in the list of unused block groups
(fs_info->unused_bgs), we check if the block group became used before
deleting it, as extents from it may have been allocated after it was added
to the list.

However even if the block group was not yet used, there may be tasks that
have only reserved space and have not yet allocated extents, and they
might be relying on the availability of the unused block group in order
to allocate extents. The reservation works first by increasing the
"bytes_may_use" field of the corresponding space_info object (which may
first require flushing delayed items, allocating a new block group, etc),
and only later a task does the actual allocation of extents.

For metadata we usually don't end up using all reserved space, as we are
pessimistic and typically account for the worst cases (need to COW every
single node in a path of a tree at maximum possible height, etc). For
data we usually reserve the exact amount of space we're going to allocate
later, except when using compression where we always reserve space based
on the uncompressed size, as compression is only triggered when writeback
starts so we don't know in advance how much space we'll actually need, or
if the data is compressible.

So don't delete an unused block group if the total size of its space_info
object minus the block group's size is less then the sum of used space and
space that may be used (space_info->bytes_may_use), as that means we have
tasks that reserved space and may need to allocate extents from the block
group. In this case, besides skipping the deletion, re-add the block group
to the list of unused block groups so that it may be reconsidered later,
in case the tasks that reserved space end up not needing to allocate
extents from it.

Allowing the deletion of the block group while we have reserved space, can
result in tasks failing to allocate metadata extents (-ENOSPC) while under
a transaction handle, resulting in a transaction abort, or failure during
writeback for the case of data extents.

CC: stable@vger.kernel.org # 6.0+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Boris Burkov <boris@bur.io>
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>
2024-02-23 09:12:28 +01:00
Filipe Manana
84b576ad44 btrfs: add and use helper to check if block group is used
commit 1693d5442c upstream.

Add a helper function to determine if a block group is being used and make
use of it at btrfs_delete_unused_bgs(). This helper will also be used in
future code changes.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Boris Burkov <boris@bur.io>
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>
2024-02-23 09:12:28 +01:00
Naohiro Aota
f91c77d2c3 btrfs: zoned: optimize hint byte for zoned allocator
[ Upstream commit 02444f2ac2 ]

Writing sequentially to a huge file on btrfs on a SMR HDD revealed a
decline of the performance (220 MiB/s to 30 MiB/s after 500 minutes).

The performance goes down because of increased latency of the extent
allocation, which is induced by a traversing of a lot of full block groups.

So, this patch optimizes the ffe_ctl->hint_byte by choosing a block group
with sufficient size from the active block group list, which does not
contain full block groups.

After applying the patch, the performance is maintained well.

Fixes: 2eda57089e ("btrfs: zoned: implement sequential extent allocation")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-31 16:17:10 -08:00
Naohiro Aota
4c45143447 btrfs: zoned: factor out prepare_allocation_zoned()
[ Upstream commit b271fee9a4 ]

Factor out prepare_allocation_zoned() for further extension. While at
it, optimize the if-branch a bit.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 02444f2ac2 ("btrfs: zoned: optimize hint byte for zoned allocator")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-31 16:17:10 -08:00
Omar Sandoval
6e6bca99e8 btrfs: don't abort filesystem when attempting to snapshot deleted subvolume
commit 7081929ab2 upstream.

If the source file descriptor to the snapshot ioctl refers to a deleted
subvolume, we get the following abort:

  BTRFS: Transaction aborted (error -2)
  WARNING: CPU: 0 PID: 833 at fs/btrfs/transaction.c:1875 create_pending_snapshot+0x1040/0x1190 [btrfs]
  Modules linked in: pata_acpi btrfs ata_piix libata scsi_mod virtio_net blake2b_generic xor net_failover virtio_rng failover scsi_common rng_core raid6_pq libcrc32c
  CPU: 0 PID: 833 Comm: t_snapshot_dele Not tainted 6.7.0-rc6 #2
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-1.fc39 04/01/2014
  RIP: 0010:create_pending_snapshot+0x1040/0x1190 [btrfs]
  RSP: 0018:ffffa09c01337af8 EFLAGS: 00010282
  RAX: 0000000000000000 RBX: ffff9982053e7c78 RCX: 0000000000000027
  RDX: ffff99827dc20848 RSI: 0000000000000001 RDI: ffff99827dc20840
  RBP: ffffa09c01337c00 R08: 0000000000000000 R09: ffffa09c01337998
  R10: 0000000000000003 R11: ffffffffb96da248 R12: fffffffffffffffe
  R13: ffff99820535bb28 R14: ffff99820b7bd000 R15: ffff99820381ea80
  FS:  00007fe20aadabc0(0000) GS:ffff99827dc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000559a120b502f CR3: 00000000055b6000 CR4: 00000000000006f0
  Call Trace:
   <TASK>
   ? create_pending_snapshot+0x1040/0x1190 [btrfs]
   ? __warn+0x81/0x130
   ? create_pending_snapshot+0x1040/0x1190 [btrfs]
   ? report_bug+0x171/0x1a0
   ? handle_bug+0x3a/0x70
   ? exc_invalid_op+0x17/0x70
   ? asm_exc_invalid_op+0x1a/0x20
   ? create_pending_snapshot+0x1040/0x1190 [btrfs]
   ? create_pending_snapshot+0x1040/0x1190 [btrfs]
   create_pending_snapshots+0x92/0xc0 [btrfs]
   btrfs_commit_transaction+0x66b/0xf40 [btrfs]
   btrfs_mksubvol+0x301/0x4d0 [btrfs]
   btrfs_mksnapshot+0x80/0xb0 [btrfs]
   __btrfs_ioctl_snap_create+0x1c2/0x1d0 [btrfs]
   btrfs_ioctl_snap_create_v2+0xc4/0x150 [btrfs]
   btrfs_ioctl+0x8a6/0x2650 [btrfs]
   ? kmem_cache_free+0x22/0x340
   ? do_sys_openat2+0x97/0xe0
   __x64_sys_ioctl+0x97/0xd0
   do_syscall_64+0x46/0xf0
   entry_SYSCALL_64_after_hwframe+0x6e/0x76
  RIP: 0033:0x7fe20abe83af
  RSP: 002b:00007ffe6eff1360 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
  RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fe20abe83af
  RDX: 00007ffe6eff23c0 RSI: 0000000050009417 RDI: 0000000000000003
  RBP: 0000000000000003 R08: 0000000000000000 R09: 00007fe20ad16cd0
  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
  R13: 00007ffe6eff13c0 R14: 00007fe20ad45000 R15: 0000559a120b6d58
   </TASK>
  ---[ end trace 0000000000000000 ]---
  BTRFS: error (device vdc: state A) in create_pending_snapshot:1875: errno=-2 No such entry
  BTRFS info (device vdc: state EA): forced readonly
  BTRFS warning (device vdc: state EA): Skipping commit of aborted transaction.
  BTRFS: error (device vdc: state EA) in cleanup_transaction:2055: errno=-2 No such entry

This happens because create_pending_snapshot() initializes the new root
item as a copy of the source root item. This includes the refs field,
which is 0 for a deleted subvolume. The call to btrfs_insert_root()
therefore inserts a root with refs == 0. btrfs_get_new_fs_root() then
finds the root and returns -ENOENT if refs == 0, which causes
create_pending_snapshot() to abort.

Fix it by checking the source root's refs before attempting the
snapshot, but after locking subvol_sem to avoid racing with deletion.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Omar Sandoval <osandov@fb.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>
2024-01-31 16:17:07 -08:00
Qu Wenruo
52e02f26d0 btrfs: defrag: reject unknown flags of btrfs_ioctl_defrag_range_args
commit 173431b274 upstream.

Add extra sanity check for btrfs_ioctl_defrag_range_args::flags.

This is not really to enhance fuzzing tests, but as a preparation for
future expansion on btrfs_ioctl_defrag_range_args.

In the future we're going to add new members, allowing more fine tuning
for btrfs defrag.  Without the -ENONOTSUPP error, there would be no way
to detect if the kernel supports those new defrag features.

CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
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>
2024-01-31 16:17:07 -08:00
David Sterba
86aff7c5f7 btrfs: don't warn if discard range is not aligned to sector
commit a208b3f132 upstream.

There's a warning in btrfs_issue_discard() when the range is not aligned
to 512 bytes, originally added in 4d89d377bb ("btrfs:
btrfs_issue_discard ensure offset/length are aligned to sector
boundaries"). We can't do sub-sector writes anyway so the adjustment is
the only thing that we can do and the warning is unnecessary.

CC: stable@vger.kernel.org # 4.19+
Reported-by: syzbot+4a4f1eba14eb5c3417d1@syzkaller.appspotmail.com
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
2024-01-31 16:17:07 -08:00
Chung-Chiang Cheng
b60f748a2f btrfs: tree-checker: fix inline ref size in error messages
commit f398e70dd6 upstream.

The error message should accurately reflect the size rather than the
type.

Fixes: f82d1c7ca8 ("btrfs: tree-checker: Add EXTENT_ITEM and METADATA_ITEM check")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.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>
2024-01-31 16:17:07 -08:00
Fedor Pchelkin
c91c247be4 btrfs: ref-verify: free ref cache before clearing mount opt
commit f03e274a8b upstream.

As clearing REF_VERIFY mount option indicates there were some errors in a
ref-verify process, a ref cache is not relevant anymore and should be
freed.

btrfs_free_ref_cache() requires REF_VERIFY option being set so call
it just before clearing the mount option.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Reported-by: syzbot+be14ed7728594dc8bd42@syzkaller.appspotmail.com
Fixes: fd708b81d9 ("Btrfs: add a extent ref verify tool")
CC: stable@vger.kernel.org # 5.4+
Closes: https://lore.kernel.org/lkml/000000000000e5a65c05ee832054@google.com/
Reported-by: syzbot+c563a3c79927971f950f@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/0000000000007fe09705fdc6086c@google.com/
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-31 16:17:07 -08:00
Omar Sandoval
9ebd514fbd btrfs: avoid copying BTRFS_ROOT_SUBVOL_DEAD flag to snapshot of subvolume being deleted
commit 3324d05478 upstream.

Sweet Tea spotted a race between subvolume deletion and snapshotting
that can result in the root item for the snapshot having the
BTRFS_ROOT_SUBVOL_DEAD flag set. The race is:

Thread 1                                      | Thread 2
----------------------------------------------|----------
btrfs_delete_subvolume                        |
  btrfs_set_root_flags(BTRFS_ROOT_SUBVOL_DEAD)|
                                              |btrfs_mksubvol
                                              |  down_read(subvol_sem)
                                              |  create_snapshot
                                              |    ...
                                              |    create_pending_snapshot
                                              |      copy root item from source
  down_write(subvol_sem)                      |

This flag is only checked in send and swap activate, which this would
cause to fail mysteriously.

create_snapshot() now checks the root refs to reject a deleted
subvolume, so we can fix this by locking subvol_sem earlier so that the
BTRFS_ROOT_SUBVOL_DEAD flag and the root refs are updated atomically.

CC: stable@vger.kernel.org # 4.14+
Reported-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Omar Sandoval <osandov@fb.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>
2024-01-31 16:17:06 -08:00
Filipe Manana
c25d7922ef btrfs: fix race between reading a directory and adding entries to it
commit 8e7f82deb0 upstream.

When opening a directory (opendir(3)) or rewinding it (rewinddir(3)), we
are not holding the directory's inode locked, and this can result in later
attempting to add two entries to the directory with the same index number,
resulting in a transaction abort, with -EEXIST (-17), when inserting the
second delayed dir index. This results in a trace like the following:

  Sep 11 22:34:59 myhostname kernel: BTRFS error (device dm-3): err add delayed dir index item(name: cockroach-stderr.log) into the insertion tree of the delayed node(root id: 5, inode id: 4539217, errno: -17)
  Sep 11 22:34:59 myhostname kernel: ------------[ cut here ]------------
  Sep 11 22:34:59 myhostname kernel: kernel BUG at fs/btrfs/delayed-inode.c:1504!
  Sep 11 22:34:59 myhostname kernel: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
  Sep 11 22:34:59 myhostname kernel: CPU: 0 PID: 7159 Comm: cockroach Not tainted 6.4.15-200.fc38.x86_64 #1
  Sep 11 22:34:59 myhostname kernel: Hardware name: ASUS ESC500 G3/P9D WS, BIOS 2402 06/27/2018
  Sep 11 22:34:59 myhostname kernel: RIP: 0010:btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel: Code: eb dd 48 (...)
  Sep 11 22:34:59 myhostname kernel: RSP: 0000:ffffa9980e0fbb28 EFLAGS: 00010282
  Sep 11 22:34:59 myhostname kernel: RAX: 0000000000000000 RBX: ffff8b10b8f4a3c0 RCX: 0000000000000000
  Sep 11 22:34:59 myhostname kernel: RDX: 0000000000000000 RSI: ffff8b177ec21540 RDI: ffff8b177ec21540
  Sep 11 22:34:59 myhostname kernel: RBP: ffff8b110cf80888 R08: 0000000000000000 R09: ffffa9980e0fb938
  Sep 11 22:34:59 myhostname kernel: R10: 0000000000000003 R11: ffffffff86146508 R12: 0000000000000014
  Sep 11 22:34:59 myhostname kernel: R13: ffff8b1131ae5b40 R14: ffff8b10b8f4a418 R15: 00000000ffffffef
  Sep 11 22:34:59 myhostname kernel: FS:  00007fb14a7fe6c0(0000) GS:ffff8b177ec00000(0000) knlGS:0000000000000000
  Sep 11 22:34:59 myhostname kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  Sep 11 22:34:59 myhostname kernel: CR2: 000000c00143d000 CR3: 00000001b3b4e002 CR4: 00000000001706f0
  Sep 11 22:34:59 myhostname kernel: Call Trace:
  Sep 11 22:34:59 myhostname kernel:  <TASK>
  Sep 11 22:34:59 myhostname kernel:  ? die+0x36/0x90
  Sep 11 22:34:59 myhostname kernel:  ? do_trap+0xda/0x100
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? do_error_trap+0x6a/0x90
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? exc_invalid_op+0x50/0x70
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? asm_exc_invalid_op+0x1a/0x20
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  ? btrfs_insert_delayed_dir_index+0x1da/0x260
  Sep 11 22:34:59 myhostname kernel:  btrfs_insert_dir_item+0x200/0x280
  Sep 11 22:34:59 myhostname kernel:  btrfs_add_link+0xab/0x4f0
  Sep 11 22:34:59 myhostname kernel:  ? ktime_get_real_ts64+0x47/0xe0
  Sep 11 22:34:59 myhostname kernel:  btrfs_create_new_inode+0x7cd/0xa80
  Sep 11 22:34:59 myhostname kernel:  btrfs_symlink+0x190/0x4d0
  Sep 11 22:34:59 myhostname kernel:  ? schedule+0x5e/0xd0
  Sep 11 22:34:59 myhostname kernel:  ? __d_lookup+0x7e/0xc0
  Sep 11 22:34:59 myhostname kernel:  vfs_symlink+0x148/0x1e0
  Sep 11 22:34:59 myhostname kernel:  do_symlinkat+0x130/0x140
  Sep 11 22:34:59 myhostname kernel:  __x64_sys_symlinkat+0x3d/0x50
  Sep 11 22:34:59 myhostname kernel:  do_syscall_64+0x5d/0x90
  Sep 11 22:34:59 myhostname kernel:  ? syscall_exit_to_user_mode+0x2b/0x40
  Sep 11 22:34:59 myhostname kernel:  ? do_syscall_64+0x6c/0x90
  Sep 11 22:34:59 myhostname kernel:  entry_SYSCALL_64_after_hwframe+0x72/0xdc

The race leading to the problem happens like this:

1) Directory inode X is loaded into memory, its ->index_cnt field is
   initialized to (u64)-1 (at btrfs_alloc_inode());

2) Task A is adding a new file to directory X, holding its vfs inode lock,
   and calls btrfs_set_inode_index() to get an index number for the entry.

   Because the inode's index_cnt field is set to (u64)-1 it calls
   btrfs_inode_delayed_dir_index_count() which fails because no dir index
   entries were added yet to the delayed inode and then it calls
   btrfs_set_inode_index_count(). This functions finds the last dir index
   key and then sets index_cnt to that index value + 1. It found that the
   last index key has an offset of 100. However before it assigns a value
   of 101 to index_cnt...

3) Task B calls opendir(3), ending up at btrfs_opendir(), where the VFS
   lock for inode X is not taken, so it calls btrfs_get_dir_last_index()
   and sees index_cnt still with a value of (u64)-1. Because of that it
   calls btrfs_inode_delayed_dir_index_count() which fails since no dir
   index entries were added to the delayed inode yet, and then it also
   calls btrfs_set_inode_index_count(). This also finds that the last
   index key has an offset of 100, and before it assigns the value 101
   to the index_cnt field of inode X...

4) Task A assigns a value of 101 to index_cnt. And then the code flow
   goes to btrfs_set_inode_index() where it increments index_cnt from
   101 to 102. Task A then creates a delayed dir index entry with a
   sequence number of 101 and adds it to the delayed inode;

5) Task B assigns 101 to the index_cnt field of inode X;

6) At some later point when someone tries to add a new entry to the
   directory, btrfs_set_inode_index() will return 101 again and shortly
   after an attempt to add another delayed dir index key with index
   number 101 will fail with -EEXIST resulting in a transaction abort.

Fix this by locking the inode at btrfs_get_dir_last_index(), which is only
only used when opening a directory or attempting to lseek on it.

Reported-by: ken <ken@bllue.org>
Link: https://lore.kernel.org/linux-btrfs/CAE6xmH+Lp=Q=E61bU+v9eWX8gYfLvu6jLYxjxjFpo3zHVPR0EQ@mail.gmail.com/
Reported-by: syzbot+d13490c82ad5353c779d@syzkaller.appspotmail.com
Link: https://lore.kernel.org/linux-btrfs/00000000000036e1290603e097e0@google.com/
Fixes: 9b378f6ad4 ("btrfs: fix infinite directory reads")
CC: stable@vger.kernel.org # 6.5+
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>
2024-01-31 16:17:06 -08:00
Filipe Manana
fd968e683b btrfs: refresh dir last index during a rewinddir(3) call
commit e60aa5da14 upstream.

When opening a directory we find what's the index of its last entry and
then store it in the directory's file handle private data (struct
btrfs_file_private::last_index), so that in the case new directory entries
are added to a directory after an opendir(3) call we don't end up in an
infinite loop (see commit 9b378f6ad4 ("btrfs: fix infinite directory
reads")) when calling readdir(3).

However once rewinddir(3) is called, POSIX states [1] that any new
directory entries added after the previous opendir(3) call, must be
returned by subsequent calls to readdir(3):

  "The rewinddir() function shall reset the position of the directory
   stream to which dirp refers to the beginning of the directory.
   It shall also cause the directory stream to refer to the current
   state of the corresponding directory, as a call to opendir() would
   have done."

We currently don't refresh the last_index field of the struct
btrfs_file_private associated to the directory, so after a rewinddir(3)
we are not returning any new entries added after the opendir(3) call.

Fix this by finding the current last index of the directory when llseek
is called against the directory.

This can be reproduced by the following C program provided by Ian Johnson:

   #include <dirent.h>
   #include <stdio.h>

   int main(void) {
     DIR *dir = opendir("test");

     FILE *file;
     file = fopen("test/1", "w");
     fwrite("1", 1, 1, file);
     fclose(file);

     file = fopen("test/2", "w");
     fwrite("2", 1, 1, file);
     fclose(file);

     rewinddir(dir);

     struct dirent *entry;
     while ((entry = readdir(dir))) {
        printf("%s\n", entry->d_name);
     }
     closedir(dir);
     return 0;
   }

Reported-by: Ian Johnson <ian@ianjohnson.dev>
Link: https://lore.kernel.org/linux-btrfs/YR1P0S.NGASEG570GJ8@ianjohnson.dev/
Fixes: 9b378f6ad4 ("btrfs: fix infinite directory reads")
CC: stable@vger.kernel.org # 6.5+
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>
2024-01-31 16:17:06 -08:00
Filipe Manana
a045b6b197 btrfs: set last dir index to the current last index when opening dir
commit 357950361c upstream.

When opening a directory for reading it, we set the last index where we
stop iteration to the value in struct btrfs_inode::index_cnt. That value
does not match the index of the most recently added directory entry but
it's instead the index number that will be assigned the next directory
entry.

This means that if after the call to opendir(3) new directory entries are
added, a readdir(3) call will return the first new directory entry. This
is fine because POSIX says the following [1]:

  "If a file is removed from or added to the directory after the most
   recent call to opendir() or rewinddir(), whether a subsequent call to
   readdir() returns an entry for that file is unspecified."

For example for the test script from commit 9b378f6ad4 ("btrfs: fix
infinite directory reads"), where we have 2000 files in a directory, ext4
doesn't return any new directory entry after opendir(3), while xfs returns
the first 13 new directory entries added after the opendir(3) call.

If we move to a shorter example with an empty directory when opendir(3) is
called, and 2 files added to the directory after the opendir(3) call, then
readdir(3) on btrfs will return the first file, ext4 and xfs return the 2
files (but in a different order). A test program for this, reported by
Ian Johnson, is the following:

   #include <dirent.h>
   #include <stdio.h>

   int main(void) {
     DIR *dir = opendir("test");

     FILE *file;
     file = fopen("test/1", "w");
     fwrite("1", 1, 1, file);
     fclose(file);

     file = fopen("test/2", "w");
     fwrite("2", 1, 1, file);
     fclose(file);

     struct dirent *entry;
     while ((entry = readdir(dir))) {
        printf("%s\n", entry->d_name);
     }
     closedir(dir);
     return 0;
   }

To make this less odd, change the behaviour to never return new entries
that were added after the opendir(3) call. This is done by setting the
last_index field of the struct btrfs_file_private attached to the
directory's file handle with a value matching btrfs_inode::index_cnt
minus 1, since that value always matches the index of the next new
directory entry and not the index of the most recently added entry.

[1] https://pubs.opengroup.org/onlinepubs/007904875/functions/readdir_r.html

Link: https://lore.kernel.org/linux-btrfs/YR1P0S.NGASEG570GJ8@ianjohnson.dev/
CC: stable@vger.kernel.org # 6.5+
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>
2024-01-31 16:17:06 -08:00
Filipe Manana
2aa515b5b5 btrfs: fix infinite directory reads
commit 9b378f6ad4 upstream.

The readdir implementation currently processes always up to the last index
it finds. This however can result in an infinite loop if the directory has
a large number of entries such that they won't all fit in the given buffer
passed to the readdir callback, that is, dir_emit() returns a non-zero
value. Because in that case readdir() will be called again and if in the
meanwhile new directory entries were added and we still can't put all the
remaining entries in the buffer, we keep repeating this over and over.

The following C program and test script reproduce the problem:

  $ cat /mnt/readdir_prog.c
  #include <sys/types.h>
  #include <dirent.h>
  #include <stdio.h>

  int main(int argc, char *argv[])
  {
    DIR *dir = opendir(".");
    struct dirent *dd;

    while ((dd = readdir(dir))) {
      printf("%s\n", dd->d_name);
      rename(dd->d_name, "TEMPFILE");
      rename("TEMPFILE", dd->d_name);
    }
    closedir(dir);
  }

  $ gcc -o /mnt/readdir_prog /mnt/readdir_prog.c

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/sdi
  MNT=/mnt/sdi

  mkfs.btrfs -f $DEV &> /dev/null
  #mkfs.xfs -f $DEV &> /dev/null
  #mkfs.ext4 -F $DEV &> /dev/null

  mount $DEV $MNT

  mkdir $MNT/testdir
  for ((i = 1; i <= 2000; i++)); do
      echo -n > $MNT/testdir/file_$i
  done

  cd $MNT/testdir
  /mnt/readdir_prog

  cd /mnt

  umount $MNT

This behaviour is surprising to applications and it's unlike ext4, xfs,
tmpfs, vfat and other filesystems, which always finish. In this case where
new entries were added due to renames, some file names may be reported
more than once, but this varies according to each filesystem - for example
ext4 never reported the same file more than once while xfs reports the
first 13 file names twice.

So change our readdir implementation to track the last index number when
opendir() is called and then make readdir() never process beyond that
index number. This gives the same behaviour as ext4.

Reported-by: Rob Landley <rob@landley.net>
Link: https://lore.kernel.org/linux-btrfs/2c8c55ec-04c6-e0dc-9c5c-8c7924778c35@landley.net/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217681
CC: stable@vger.kernel.org # 5.15
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>
2024-01-31 16:17:05 -08:00
David Disseldorp
562850a008 btrfs: sysfs: validate scrub_speed_max value
commit 2b0122aaa8 upstream.

The value set as scrub_speed_max accepts size with suffixes
(k/m/g/t/p/e) but we should still validate it for trailing characters,
similar to what we do with chunk_size_store.

CC: stable@vger.kernel.org # 5.15+
Signed-off-by: David Disseldorp <ddiss@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-01-31 16:16:58 -08:00
Christoph Hellwig
820a7802f2 btrfs: mark the len field in struct btrfs_ordered_sum as unsigned
[ Upstream commit 6e4b2479ab ]

len can't ever be negative, so mark it as an u32 instead of int.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Stable-dep-of: 9e65bfca24 ("btrfs: fix qgroup_free_reserved_data int overflow")
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-10 17:10:35 +01:00
Boris Burkov
ab220f4f5c btrfs: fix qgroup_free_reserved_data int overflow
[ Upstream commit 9e65bfca24 ]

The reserved data counter and input parameter is a u64, but we
inadvertently accumulate it in an int. Overflowing that int results in
freeing the wrong amount of data and breaking reserve accounting.

Unfortunately, this overflow rot spreads from there, as the qgroup
release/free functions rely on returning an int to take advantage of
negative values for error codes.

Therefore, the full fix is to return the "released" or "freed" amount by
a u64 argument and to return 0 or negative error code via the return
value.

Most of the call sites simply ignore the return value, though some
of them handle the error and count the returned bytes. Change all of
them accordingly.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-10 17:10:35 +01:00
Naohiro Aota
3c42cc437d btrfs: zoned: no longer count fresh BG region as zone unusable
[ Upstream commit 6a8ebc773e ]

Now that we switched to write time activation, we no longer need to (and
must not) count the fresh region as zone unusable. This commit is similar
to revert of commit fa2068d7e9 ("btrfs: zoned: count fresh BG
region as zone unusable").

Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-01 12:39:06 +00:00
Boris Burkov
730b3322b8 btrfs: don't clear qgroup reserved bit in release_folio
commit a86805504b upstream.

The EXTENT_QGROUP_RESERVED bit is used to "lock" regions of the file for
duplicate reservations. That is two writes to that range in one
transaction shouldn't create two reservations, as the reservation will
only be freed once when the write finally goes down. Therefore, it is
never OK to clear that bit without freeing the associated qgroup
reserve. At this point, we don't want to be freeing the reserve, so mask
off the bit.

CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-20 17:00:26 +01:00
Boris Burkov
9b670e1b64 btrfs: free qgroup reserve when ORDERED_IOERR is set
commit f63e1164b9 upstream.

An ordered extent completing is a critical moment in qgroup reserve
handling, as the ownership of the reservation is handed off from the
ordered extent to the delayed ref. In the happy path we release (unlock)
but do not free (decrement counter) the reservation, and the delayed ref
drives the free. However, on an error, we don't create a delayed ref,
since there is no ref to add. Therefore, free on the error path.

CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-12-20 17:00:26 +01:00
Josef Bacik
56f762659a btrfs: do not allow non subvolume root targets for snapshot
commit a8892fd719 upstream.

Our btrfs subvolume snapshot <source> <destination> utility enforces
that <source> is the root of the subvolume, however this isn't enforced
in the kernel.  Update the kernel to also enforce this limitation to
avoid problems with other users of this ioctl that don't have the
appropriate checks in place.

Reported-by: Martin Michaelis <code@mgjm.de>
CC: stable@vger.kernel.org # 4.14+
Reviewed-by: Neal Gompa <neal@gompa.dev>
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>
2023-12-20 17:00:25 +01:00