Commit Graph
1248727 Commits
Author SHA1 Message Date
Chengming Zhou a78e41a67b udf: remove SLAB_MEM_SPREAD flag usage
The SLAB_MEM_SPREAD flag is already a no-op after removal of SLAB
allocator and in [1] it was fully deprecated. Remove its usage so we can
delete it from slab. No functional change.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/
Message-Id: <20240224135229.830356-1-chengming.zhou@linux.dev>
2024-03-05 15:16:15 +01:00
Chengming Zhou e29dd522c1 quota: remove SLAB_MEM_SPREAD flag usage
The SLAB_MEM_SPREAD flag is already a no-op after removal of SLAB
allocator and in [1] it was fully deprecated. Remove its usage so we can
delete it from slab. No functional change.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/
Message-Id: <20240224135118.830073-1-chengming.zhou@linux.dev>
2024-03-05 15:15:50 +01:00
Chengming Zhou bbff9dc7d8 isofs: remove SLAB_MEM_SPREAD flag usage
The SLAB_MEM_SPREAD flag is already a no-op after removal of SLAB
allocator and in [1] it was fully deprecated. Remove its usage so we can
delete it from slab. No functional change.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/
Message-Id: <20240224134901.829591-1-chengming.zhou@linux.dev>
2024-03-05 15:15:43 +01:00
Chengming Zhou 0d5fb7720b ext2: remove SLAB_MEM_SPREAD flag usage
The SLAB_MEM_SPREAD flag is already a no-op after removal of SLAB
allocator and in [1] it was fully deprecated. Remove its usage so we can
delete it from slab. No functional change.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/all/20240223-slab-cleanup-flags-v2-1-02f1753e8303@suse.cz/
Message-Id: <20240224134816.829424-1-chengming.zhou@linux.dev>
2024-03-05 15:09:41 +01:00
Michael Opdenacker b960e8093e ext2: mark as deprecated
Add a DEPRECATED keyword to the kernel parameter description,
to warn users that this filesystem doesn't support dates beyond 2038.

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240222095001.137660-1-michael.opdenacker@bootlin.com>
2024-02-22 11:14:42 +01:00
Eric Sandeen c4e89cc674 udf: convert to new mount API
Convert the UDF filesystem to the new mount API.

UDF is slightly unique in that it always preserves prior mount
options across a remount, so that's handled by udf_init_options().

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <fcb3faf3-e2df-450c-b37a-11000c274585@redhat.com>
2024-02-21 13:55:30 +01:00
Eric Sandeen 7a8e72c16e udf: convert novrs to an option flag
There's no reason to treat novers specially, convert it
to a flag in uopt->flags like other flag options.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <b5d53492-b99a-4b3c-82c0-581df9a9e384@redhat.com>
2024-02-21 13:55:30 +01:00
Chao Yu d27f41eed5 MAINTAINERS: add missing git address for ext2 entry
ext2 git address is missing, add it.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240219063718.3682824-1-chao@kernel.org>
2024-02-19 12:57:12 +01:00
Jan Kara a898cb621a quota: Detect loops in quota tree
Syzbot has found that when it creates corrupted quota files where the
quota tree contains a loop, we will deadlock when tryling to insert a
dquot. Add loop detection into functions traversing the quota tree.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-02-12 14:14:49 +01:00
Jan Kara ccb49011bb quota: Properly annotate i_dquot arrays with __rcu
Dquots pointed to from i_dquot arrays in inodes are protected by
dquot_srcu. Annotate them as such and change .get_dquots callback to
return properly annotated pointer to make sparse happy.

Fixes: b9ba6f94b2 ("quota: remove dqptr_sem")
Signed-off-by: Jan Kara <jack@suse.cz>
2024-02-08 12:04:59 +01:00
Jan Kara 179b8c97eb quota: Fix rcu annotations of inode dquot pointers
Dquot pointers in i_dquot array in the inode are protected by
dquot_srcu. Annotate the array pointers with __rcu, perform the locked
dereferences with srcu_dereference_check() instead of plain reads, and
set the array elements with rcu_assign_pointer().

Fixes: b9ba6f94b2 ("quota: remove dqptr_sem")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402061900.rTuYDlo6-lkp@intel.com/
Signed-off-by: Jan Kara <jack@suse.cz>
2024-02-08 12:04:59 +01:00
Alex Henrie 4243bf80c7 isofs: handle CDs with bad root inode but good Joliet root directory
I have a CD copy of the original Tom Clancy's Ghost Recon game from
2001. The disc mounts without error on Windows, but on Linux mounting
fails with the message "isofs_fill_super: get root inode failed". The
error originates in isofs_read_inode, which returns -EIO because de_len
is 0. The superblock on this disc appears to be intentionally corrupt as
a form of copy protection.

When the root inode is unusable, instead of giving up immediately, try
to continue with the Joliet file table. This fixes the Ghost Recon CD
and probably other copy-protected CDs too.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240208022134.451490-1-alexhenrie24@gmail.com>
2024-02-08 11:59:37 +01:00
Jan Kara c8f1140cb8 udf: Avoid invalid LVID used on mount
udf_load_logicalvolint() loads logical volume integrity descriptors.
Since there can be multiple blocks with LVIDs, we verify the contents of
only the last (prevailing) LVID found. However if we fail to load the
last LVID (either due to IO error or because it's checksum fails to
match), we never perform the verification of validity of the LVID we are
going to use. If such LVID contains invalid data, we can hit
out-of-bounds access or similar issues. Fix the problem by verifying
each LVID we are potentially going to accept.

Reported-by: Robert Morris <rtm@csail.mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
2024-02-05 16:51:59 +01:00
Wang Jianjian d0aa72604f quota: Fix potential NULL pointer dereference
Below race may cause NULL pointer dereference

P1					P2
dquot_free_inode			quota_off
					  drop_dquot_ref
					   remove_dquot_ref
					   dquots = i_dquot(inode)
  dquots = i_dquot(inode)
  srcu_read_lock
  dquots[cnt]) != NULL (1)
					     dquots[type] = NULL (2)
  spin_lock(&dquots[cnt]->dq_dqb_lock) (3)
   ....

If dquot_free_inode(or other routines) checks inode's quota pointers (1)
before quota_off sets it to NULL(2) and use it (3) after that, NULL pointer
dereference will be triggered.

So let's fix it by using a temporary pointer to avoid this issue.

Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Message-Id: <20240202081852.2514092-1-wangjianjian3@huawei.com>
2024-02-05 15:57:34 +01:00
Jan Kara a1e1b2beca quota: Drop GFP_NOFS instances under dquot->dq_lock and dqio_sem
Quota code acquires dquot->dq_lock whenever reading / writing dquot.
When reading / writing quota info we hold dqio_sem.  Since these locks
can be acquired during inode reclaim (through dquot_drop() -> dqput() ->
dquot_release()) we are setting nofs allocation context whenever
acquiring these locks. Hence there's no need to use GFP_NOFS allocations
in quota code doing IO. Just switch it to GFP_KERNEL.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:11 +01:00
Jan Kara 6c5026c1ef quota: Set nofs allocation context when acquiring dqio_sem
dqio_sem can be acquired during inode reclaim through dquot_drop() ->
dqput() -> dquot_release() -> write_file_info() context. In some cases
(most notably through dquot_get_next_id()) it can be acquired without
holding dquot->dq_lock (which already sets nofs allocation context). So
we need to set nofs allocation context when acquiring it as well.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:11 +01:00
Jan Kara c3e637c7f0 ext2: Remove GFP_NOFS use in ext2_xattr_cache_insert()
ext2_xattr_cache_insert() calls mb_cache_entry_create() with GFP_NOFS
because it is called under EXT2_I(inode)->xattr_sem. However xattr_sem
or any higher ranking lock is not acquired on fs reclaim path for ext2
at least since we don't do page writeback from direct reclaim.  Thus
GFP_NOFS is not needed.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:11 +01:00
Jan Kara 36975616ea ext2: Drop GFP_NOFS use in ext2_get_blocks()
ext2_get_blocks() calls sb_issue_zeroout() with GFP_NOFS flag. However
the call is performed under inode->i_rwsem and
EXT2_I(inode)->i_truncate_mutex neither of which is acquired during
direct fs reclaim. So it is safe to change the gfp mask to GFP_KERNEL.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:10 +01:00
Jan Kara dbc056f83b ext2: Drop GFP_NOFS allocation from ext2_init_block_alloc_info()
The allocation happens under inode->i_rwsem and
EXT2_I(inode)->i_truncate_mutex. Neither of them is acquired during
direct fs reclaim so the allocation can be changed to GFP_KERNEL.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:10 +01:00
Jan Kara 38f8af2a71 udf: Remove GFP_NOFS allocation in udf_expand_file_adinicb()
udf_expand_file_adinicb() is called under inode->i_rwsem and
mapping->invalidate_lock. i_rwsem is safe wrt fs reclaim,
invalidate_lock on this inode is safe as well (we hold inode reference
so reclaim will not touch it, furthermore even lockdep should not
complain as invalidate_lock is acquired from udf_evict_inode() only when
truncating inode which should not happen from fs reclaim).

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:10 +01:00
Jan Kara b27ffdc17c udf: Avoid GFP_NOFS allocation in udf_load_pvoldesc()
udf_load_pvoldesc() is called only during mount when it is safe to
enter fs reclaim (we hold only s_umount semaphore). Change GFP_NOFS to
GFP_KERNEL allocation.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:10 +01:00
Jan Kara 2ed0d3d4fe udf: Avoid GFP_NOFS allocation in udf_symlink()
The GFP_NOFS allocation in udf_symlink() is called only under
inode->i_rwsem and UDF_I(inode)->i_data_sem. The first is safe wrt
reclaim, the second should be as well but allocating unde this lock is
actually unnecessary. Move the allocation from under i_data_sem and
change it to GFP_KERNEL.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:10 +01:00
Jan Kara f6766303c0 udf: Remove GFP_NOFS from dir iteration code
Directory iteration code was using GFP_NOFS allocations in two places.
However the code is called only under inode->i_rwsem which is generally
safe wrt reclaim. So we can do the allocations with GFP_KERNEL instead.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-23 19:21:10 +01:00
Jan Kara 249f374eb9 quota: Remove BUG_ON from dqget()
dqget() checks whether dquot->dq_sb is set when returning it using
BUG_ON. Firstly this doesn't work as an invalidation check for quite
some time (we release dquot with dq_sb set these days), secondly using
BUG_ON is quite harsh. Use WARN_ON_ONCE and check whether dquot is still
hashed instead.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-22 12:56:20 +01:00
Jan Kara d44c576637 quota: Remove BUG_ON in dquot_load_quota_sb()
The case when someone passes DQUOT_SUSPENDED flag to
dquot_load_quota_sb() is easy to handle. So just WARN_ON_ONCE and bail
with error if that happens instead of calling BUG_ON which is likely to
lockup the machine.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-22 12:56:20 +01:00
Jan Kara c8238508c8 quota: Replace BUG_ON in dqput()
The BUG_ON in dqput() will likely take the whole machine down when it
hits. Replace it with WARN_ON_ONCE() instead and stop hiding that behind
CONFIG_QUOTA_DEBUG.

Signed-off-by: Jan Kara <jack@suse.cz>
2024-01-22 12:56:20 +01:00
Linus Torvalds 6613476e22 Linux 6.8-rc1 v6.8-rc1 2024-01-21 14:11:32 -08:00
Linus Torvalds 35a4474b5c Merge tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs
Pull more bcachefs updates from Kent Overstreet:
 "Some fixes, Some refactoring, some minor features:

   - Assorted prep work for disk space accounting rewrite

   - BTREE_TRIGGER_ATOMIC: after combining our trigger callbacks, this
     makes our trigger context more explicit

   - A few fixes to avoid excessive transaction restarts on
     multithreaded workloads: fstests (in addition to ktest tests) are
     now checking slowpath counters, and that's shaking out a few bugs

   - Assorted tracepoint improvements

   - Starting to break up bcachefs_format.h and move on disk types so
     they're with the code they belong to; this will make room to start
     documenting the on disk format better.

   - A few minor fixes"

* tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs: (46 commits)
  bcachefs: Improve inode_to_text()
  bcachefs: logged_ops_format.h
  bcachefs: reflink_format.h
  bcachefs; extents_format.h
  bcachefs: ec_format.h
  bcachefs: subvolume_format.h
  bcachefs: snapshot_format.h
  bcachefs: alloc_background_format.h
  bcachefs: xattr_format.h
  bcachefs: dirent_format.h
  bcachefs: inode_format.h
  bcachefs; quota_format.h
  bcachefs: sb-counters_format.h
  bcachefs: counters.c -> sb-counters.c
  bcachefs: comment bch_subvolume
  bcachefs: bch_snapshot::btime
  bcachefs: add missing __GFP_NOWARN
  bcachefs: opts->compression can now also be applied in the background
  bcachefs: Prep work for variable size btree node buffers
  bcachefs: grab s_umount only if snapshotting
  ...
2024-01-21 14:01:12 -08:00
Linus Torvalds 4fbbed7872 Merge tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
 "Updates for time and clocksources:

   - A fix for the idle and iowait time accounting vs CPU hotplug.

     The time is reset on CPU hotplug which makes the accumulated
     systemwide time jump backwards.

   - Assorted fixes and improvements for clocksource/event drivers"

* tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick-sched: Fix idle and iowait sleeptime accounting vs CPU hotplug
  clocksource/drivers/ep93xx: Fix error handling during probe
  clocksource/drivers/cadence-ttc: Fix some kernel-doc warnings
  clocksource/drivers/timer-ti-dm: Fix make W=n kerneldoc warnings
  clocksource/timer-riscv: Add riscv_clock_shutdown callback
  dt-bindings: timer: Add StarFive JH8100 clint
  dt-bindings: timer: thead,c900-aclint-mtimer: separate mtime and mtimecmp regs
2024-01-21 11:14:40 -08:00
Linus Torvalds 7b297a5cc9 Merge tag 'powerpc-6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc fixes from Aneesh Kumar:

 - Increase default stack size to 32KB for Book3S

Thanks to Michael Ellerman.

* tag 'powerpc-6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s: Increase default stack size to 32KB
2024-01-21 11:04:29 -08:00
Kent Overstreet 249f441f83 bcachefs: Improve inode_to_text()
Add line breaks - inode_to_text() is now much easier to read.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:11 -05:00
Kent Overstreet d826cc57c5 bcachefs: logged_ops_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:11 -05:00
Kent Overstreet 8d52ba60c4 bcachefs: reflink_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:11 -05:00
Kent Overstreet b2fa1b633b bcachefs; extents_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:11 -05:00
Kent Overstreet 0560eb9abf bcachefs: ec_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:11 -05:00
Kent Overstreet c6c4ff6507 bcachefs: subvolume_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:11 -05:00
Kent Overstreet 8fed323b14 bcachefs: snapshot_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet d455179fce bcachefs: alloc_background_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet 72e0801049 bcachefs: xattr_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet 7ffc4daa5f bcachefs: dirent_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet b36425da71 bcachefs: inode_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet 82de6207fb bcachefs; quota_format.h
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet 43314801a4 bcachefs: sb-counters_format.h
bcachefs_format.h has gotten too big; let's do some organizing.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet 3a58dfbc46 bcachefs: counters.c -> sb-counters.c
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet 12207f49ef bcachefs: comment bch_subvolume
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet d32088f2f2 bcachefs: bch_snapshot::btime
Add a field to bch_snapshot for creation time; this will be important
when we start exposing the snapshot tree to userspace.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet 7be0208fc9 bcachefs: add missing __GFP_NOWARN
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet d7e77f53e9 bcachefs: opts->compression can now also be applied in the background
The "apply this compression method in the background" paths now use the
compression option if background_compression is not set; this means that
setting or changing the compression option will cause existing data to
be compressed accordingly in the background.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Kent Overstreet ec4edd7b9d bcachefs: Prep work for variable size btree node buffers
bcachefs btree nodes are big - typically 256k - and btree roots are
pinned in memory. As we're now up to 18 btrees, we now have significant
memory overhead in mostly empty btree roots.

And in the future we're going to start enforcing that certain btree node
boundaries exist, to solve lock contention issues - analagous to XFS's
AGIs.

Thus, we need to start allocating smaller btree node buffers when we
can. This patch changes code that refers to the filesystem constant
c->opts.btree_node_size to refer to the btree node buffer size -
btree_buf_bytes() - where appropriate.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00
Su Yue 2acc59dd88 bcachefs: grab s_umount only if snapshotting
When I was testing mongodb over bcachefs with compression,
there is a lockdep warning when snapshotting mongodb data volume.

$ cat test.sh
prog=bcachefs

$prog subvolume create /mnt/data
$prog subvolume create /mnt/data/snapshots

while true;do
    $prog subvolume snapshot /mnt/data /mnt/data/snapshots/$(date +%s)
    sleep 1s
done

$ cat /etc/mongodb.conf
systemLog:
  destination: file
  logAppend: true
  path: /mnt/data/mongod.log

storage:
  dbPath: /mnt/data/

lockdep reports:
[ 3437.452330] ======================================================
[ 3437.452750] WARNING: possible circular locking dependency detected
[ 3437.453168] 6.7.0-rc7-custom+ #85 Tainted: G            E
[ 3437.453562] ------------------------------------------------------
[ 3437.453981] bcachefs/35533 is trying to acquire lock:
[ 3437.454325] ffffa0a02b2b1418 (sb_writers#10){.+.+}-{0:0}, at: filename_create+0x62/0x190
[ 3437.454875]
               but task is already holding lock:
[ 3437.455268] ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.456009]
               which lock already depends on the new lock.

[ 3437.456553]
               the existing dependency chain (in reverse order) is:
[ 3437.457054]
               -> #3 (&type->s_umount_key#48){.+.+}-{3:3}:
[ 3437.457507]        down_read+0x3e/0x170
[ 3437.457772]        bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.458206]        __x64_sys_ioctl+0x93/0xd0
[ 3437.458498]        do_syscall_64+0x42/0xf0
[ 3437.458779]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.459155]
               -> #2 (&c->snapshot_create_lock){++++}-{3:3}:
[ 3437.459615]        down_read+0x3e/0x170
[ 3437.459878]        bch2_truncate+0x82/0x110 [bcachefs]
[ 3437.460276]        bchfs_truncate+0x254/0x3c0 [bcachefs]
[ 3437.460686]        notify_change+0x1f1/0x4a0
[ 3437.461283]        do_truncate+0x7f/0xd0
[ 3437.461555]        path_openat+0xa57/0xce0
[ 3437.461836]        do_filp_open+0xb4/0x160
[ 3437.462116]        do_sys_openat2+0x91/0xc0
[ 3437.462402]        __x64_sys_openat+0x53/0xa0
[ 3437.462701]        do_syscall_64+0x42/0xf0
[ 3437.462982]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.463359]
               -> #1 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}:
[ 3437.463843]        down_write+0x3b/0xc0
[ 3437.464223]        bch2_write_iter+0x5b/0xcc0 [bcachefs]
[ 3437.464493]        vfs_write+0x21b/0x4c0
[ 3437.464653]        ksys_write+0x69/0xf0
[ 3437.464839]        do_syscall_64+0x42/0xf0
[ 3437.465009]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.465231]
               -> #0 (sb_writers#10){.+.+}-{0:0}:
[ 3437.465471]        __lock_acquire+0x1455/0x21b0
[ 3437.465656]        lock_acquire+0xc6/0x2b0
[ 3437.465822]        mnt_want_write+0x46/0x1a0
[ 3437.465996]        filename_create+0x62/0x190
[ 3437.466175]        user_path_create+0x2d/0x50
[ 3437.466352]        bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs]
[ 3437.466617]        __x64_sys_ioctl+0x93/0xd0
[ 3437.466791]        do_syscall_64+0x42/0xf0
[ 3437.466957]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.467180]
               other info that might help us debug this:

[ 3437.469670] 2 locks held by bcachefs/35533:
               other info that might help us debug this:

[ 3437.467507] Chain exists of:
                 sb_writers#10 --> &c->snapshot_create_lock --> &type->s_umount_key#48

[ 3437.467979]  Possible unsafe locking scenario:

[ 3437.468223]        CPU0                    CPU1
[ 3437.468405]        ----                    ----
[ 3437.468585]   rlock(&type->s_umount_key#48);
[ 3437.468758]                                lock(&c->snapshot_create_lock);
[ 3437.469030]                                lock(&type->s_umount_key#48);
[ 3437.469291]   rlock(sb_writers#10);
[ 3437.469434]
                *** DEADLOCK ***

[ 3437.469670] 2 locks held by bcachefs/35533:
[ 3437.469838]  #0: ffffa0a02ce00a88 (&c->snapshot_create_lock){++++}-{3:3}, at: bch2_fs_file_ioctl+0x1e3/0xc90 [bcachefs]
[ 3437.470294]  #1: ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.470744]
               stack backtrace:
[ 3437.470922] CPU: 7 PID: 35533 Comm: bcachefs Kdump: loaded Tainted: G            E      6.7.0-rc7-custom+ #85
[ 3437.471313] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 3437.471694] Call Trace:
[ 3437.471795]  <TASK>
[ 3437.471884]  dump_stack_lvl+0x57/0x90
[ 3437.472035]  check_noncircular+0x132/0x150
[ 3437.472202]  __lock_acquire+0x1455/0x21b0
[ 3437.472369]  lock_acquire+0xc6/0x2b0
[ 3437.472518]  ? filename_create+0x62/0x190
[ 3437.472683]  ? lock_is_held_type+0x97/0x110
[ 3437.472856]  mnt_want_write+0x46/0x1a0
[ 3437.473025]  ? filename_create+0x62/0x190
[ 3437.473204]  filename_create+0x62/0x190
[ 3437.473380]  user_path_create+0x2d/0x50
[ 3437.473555]  bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs]
[ 3437.473819]  ? lock_acquire+0xc6/0x2b0
[ 3437.474002]  ? __fget_files+0x2a/0x190
[ 3437.474195]  ? __fget_files+0xbc/0x190
[ 3437.474380]  ? lock_release+0xc5/0x270
[ 3437.474567]  ? __x64_sys_ioctl+0x93/0xd0
[ 3437.474764]  ? __pfx_bch2_fs_file_ioctl+0x10/0x10 [bcachefs]
[ 3437.475090]  __x64_sys_ioctl+0x93/0xd0
[ 3437.475277]  do_syscall_64+0x42/0xf0
[ 3437.475454]  entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.475691] RIP: 0033:0x7f2743c313af
======================================================

In __bch2_ioctl_subvolume_create(), we grab s_umount unconditionally
and unlock it at the end of the function. There is a comment
"why do we need this lock?" about the lock coming from
commit 42d237320e ("bcachefs: Snapshot creation, deletion")
The reason is that __bch2_ioctl_subvolume_create() calls
sync_inodes_sb() which enforce locked s_umount to writeback all dirty
nodes before doing snapshot works.

Fix it by read locking s_umount for snapshotting only and unlocking
s_umount after sync_inodes_sb().

Signed-off-by: Su Yue <glass.su@suse.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
2024-01-21 13:27:10 -05:00