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Author SHA1 Message Date
Jeff Layton
b6aaba5b76 filelock: convert fl_blocker to file_lock_core 
Both locks and leases deal with fl_blocker. Switch the fl_blocker
pointer in struct file_lock_core to point to the file_lock_core of the
blocker instead of a file_lock structure.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-26-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:40 +01:00
Jeff Layton
b6be371400 filelock: convert __locks_insert_block, conflict and deadlock checks to use file_lock_core 
Have both __locks_insert_block and the deadlock and conflict checking
functions take a struct file_lock_core pointer instead of a struct
file_lock one. Also, change posix_locks_deadlock to return bool.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-25-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:39 +01:00
Jeff Layton
1a62c22a15 filelock: make __locks_delete_block and __locks_wake_up_blocks take file_lock_core 
Convert __locks_delete_block and __locks_wake_up_blocks to take a struct
file_lock_core pointer.

While we could do this in another way, we're going to need to add a
file_lock() helper function later anyway, so introduce and use it now.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-24-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:39 +01:00
Jeff Layton
1a6c75d4bb filelock: convert locks_{insert,delete}_global_blocked 
Have locks_insert_global_blocked and locks_delete_global_blocked take a
struct file_lock_core pointer.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-23-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:39 +01:00
Jeff Layton
4629172fd7 filelock: make locks_{insert,delete}_global_locks take file_lock_core arg 
Convert these functions to take a file_lock_core instead of a file_lock.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-22-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:39 +01:00
Jeff Layton
ad399740bd filelock: convert posix_owner_key to take file_lock_core arg 
Convert posix_owner_key to take struct file_lock_core pointer, and fix
up the callers to pass one in.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-21-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:39 +01:00
Jeff Layton
9bb430a89d filelock: make posix_same_owner take file_lock_core pointers 
Change posix_same_owner to take struct file_lock_core pointers, and
convert the callers to pass those in.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-20-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:38 +01:00
Jeff Layton
fde4951834 filelock: convert more internal functions to use file_lock_core 
Convert more internal fs/locks.c functions to take and deal with struct
file_lock_core instead of struct file_lock:

- locks_dump_ctx_list
- locks_check_ctx_file_list
- locks_release_private
- locks_owner_has_blockers

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-19-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:38 +01:00
Jeff Layton
4ca52f5398 filelock: have fs/locks.c deal with file_lock_core directly 
Convert fs/locks.c to access fl_core fields direcly rather than using
the backward-compatibility macros. Most of this was done with
coccinelle, with a few by-hand fixups.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-18-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:38 +01:00
Jeff Layton
a69ce85ec9 filelock: split common fields into struct file_lock_core 
In a future patch, we're going to split file leases into their own
structure. Since a lot of the underlying machinery uses the same fields
move those into a new file_lock_core, and embed that inside struct
file_lock.

For now, add some macros to ensure that we can continue to build while
the conversion is in progress.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-17-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:38 +01:00
Jeff Layton
3d40f78169 filelock: drop the IS_* macros 
These don't add a lot of value over just open-coding the flag check.

Suggested-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-16-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:37 +01:00
Jeff Layton
6a277077ac smb/server: convert to using new filelock helpers 
Convert to using the new file locking helper functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-15-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:37 +01:00
Jeff Layton
2cd114294d smb/client: convert to using new filelock helpers 
Convert to using the new file locking helper functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-14-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:37 +01:00
Jeff Layton
64f92a554f ocfs2: convert to using new filelock helpers 
Convert to using the new file locking helper functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-13-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:37 +01:00
Jeff Layton
60f3154d19 nfsd: convert to using new filelock helpers 
Convert to using the new file locking helper functions. Also, in later
patches we're going to introduce some macros with names that clash with
the variable names in nfsd4_lock. Rename them.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-12-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:36 +01:00
Jeff Layton
d7c9616be0 nfs: convert to using new filelock helpers 
Convert to using the new file locking helper functions. Also, in later
patches we're going to introduce some temporary macros with names that
clash with the variable name in nfs4_proc_unlck. Rename it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-11-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:36 +01:00
Jeff Layton
872584f1bb lockd: convert to using new filelock helpers 
Convert to using the new file locking helper functions. Also in later
patches we're going to introduce some macros with names that clash with
the variable names in nlmclnt_lock. Rename them.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-10-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:36 +01:00
Jeff Layton
b4c6d52d8a gfs2: convert to using new filelock helpers 
Convert to using the new file locking helper functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-9-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:36 +01:00
Jeff Layton
11ff73082f dlm: convert to using new filelock helpers 
Convert to using the new file locking helper functions. Also, in later
patches we're going to introduce some temporary macros with names that
clash with the variable name in dlm_posix_unlock. Rename it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-8-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:36 +01:00
Jeff Layton
75e9570c93 ceph: convert to using new filelock helpers 
Convert to using the new file locking helper functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-7-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:35 +01:00
Jeff Layton
76698510f5 afs: convert to using new filelock helpers 
Convert to using the new file locking helper functions. Also, in later
patches we're going to introduce macros that conflict with the variable
name in afs_next_locker. Rename it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-6-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:35 +01:00
Jeff Layton
75a1bbe60a 9p: rename fl_type variable in v9fs_file_do_lock 
In later patches, we're going to introduce some macros that conflict
with the variable name here. Rename it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-5-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:35 +01:00
Jeff Layton
75cabec011 filelock: add some new helper functions 
In later patches we're going to embed some common fields into a new
structure inside struct file_lock. Smooth the transition by adding some
new helper functions, and converting the core file locking code to use
them.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-4-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-05 13:11:35 +01:00
Jeff Layton
6021d62c67 filelock: rename fl_pid variable in lock_get_status 
In later patches we're going to introduce some macros that will clash
with the variable name here. Rename it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-3-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-02 12:09:05 +01:00
Jeff Layton
587a67b683 filelock: rename some fields in tracepoints 
In later patches we're going to introduce some macros with names that
clash with fields here. To prevent problems building, just rename the
fields in the trace entry structures.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-2-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-02 12:09:04 +01:00
Jeff Layton
0e9876d8e8 filelock: fl_pid field should be signed int 
This field has been unsigned for a very long time, but most users of the
struct file_lock and the file locking internals themselves treat it as a
signed value. Change it to be pid_t (which is a signed int).

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-1-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2024-02-02 12:09:04 +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