Commit Graph
486 Commits
Author SHA1 Message Date
Linus Torvalds 323bbfcf1e Convert 'alloc_flex' family to use the new default GFP_KERNEL argument
This is the exact same thing as the 'alloc_obj()' version, only much
smaller because there are a lot fewer users of the *alloc_flex()
interface.

As with alloc_obj() version, this was done entirely with mindless brute
force, using the same script, except using 'flex' in the pattern rather
than 'objs*'.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-02-21 17:09:51 -08:00
Kees Cook 69050f8d6d treewide: Replace kmalloc with kmalloc_obj for non-scalar types
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:

Single allocations:	kmalloc(sizeof(TYPE), ...)
are replaced with:	kmalloc_obj(TYPE, ...)

Array allocations:	kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with:	kmalloc_objs(TYPE, COUNT, ...)

Flex array allocations:	kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with:	kmalloc_flex(*PTR, FAM, COUNT, ...)

(where TYPE may also be *VAR)

The resulting allocations no longer return "void *", instead returning
"TYPE *".

Signed-off-by: Kees Cook <kees@kernel.org>
2026-02-21 01:02:28 -08:00
Linus Torvalds ff661eeee2 Merge tag 'cgroup-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:

 - cpuset changes:

    - Continue separating v1 and v2 implementations by moving more
      v1-specific logic into cpuset-v1.c

    - Improve partition handling. Sibling partitions are no longer
      invalidated on cpuset.cpus conflict, cpuset.cpus changes no longer
      fail in v2, and effective_xcpus computation is made consistent

    - Fix partition effective CPUs overlap that caused a warning on
      cpuset removal when sibling partitions shared CPUs

 - Increase the maximum cgroup subsystem count from 16 to 32 to
   accommodate future subsystem additions

 - Misc cleanups and selftest improvements including switching to
   css_is_online() helper, removing dead code and stale documentation
   references, using lockdep_assert_cpuset_lock_held() consistently, and
   adding polling helpers for asynchronously updated cgroup statistics

* tag 'cgroup-for-6.20' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
  cpuset: fix overlap of partition effective CPUs
  cgroup: increase maximum subsystem count from 16 to 32
  cgroup: Remove stale cpu.rt.max reference from documentation
  cpuset: replace direct lockdep_assert_held() with lockdep_assert_cpuset_lock_held()
  cgroup/cpuset: Move the v1 empty cpus/mems check to cpuset1_validate_change()
  cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict
  cgroup/cpuset: Don't fail cpuset.cpus change in v2
  cgroup/cpuset: Consistently compute effective_xcpus in update_cpumasks_hier()
  cgroup/cpuset: Streamline rm_siblings_excl_cpus()
  cpuset: remove dead code in cpuset-v1.c
  cpuset: remove v1-specific code from generate_sched_domains
  cpuset: separate generate_sched_domains for v1 and v2
  cpuset: move update_domain_attr_tree to cpuset_v1.c
  cpuset: add cpuset1_init helper for v1 initialization
  cpuset: add cpuset1_online_css helper for v1-specific operations
  cpuset: add lockdep_assert_cpuset_lock_held helper
  cpuset: Remove unnecessary checks in rebuild_sched_domains_locked
  cgroup: switch to css_is_online() helper
  selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants
  selftests: cgroup: make test_memcg_sock robust against delayed sock stats
  ...
2026-02-11 13:20:50 -08:00
Linus Torvalds 74554251df Merge tag 'vfs-7.0-rc1.nonblocking_timestamps' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs timestamp updates from Christian Brauner:
 "This contains the changes to support non-blocking timestamp updates.

  Since commit 66fa3cedf1 ("fs: Add async write file modification
  handling") file_update_time_flags() unconditionally returns -EAGAIN
  when any timestamp needs updating and IOCB_NOWAIT is set. This makes
  non-blocking direct writes impossible on file systems with granular
  enough timestamps, which in practice means all of them.

  This reworks the timestamp update path to propagate IOCB_NOWAIT
  through ->update_time so that file systems which can update timestamps
  without blocking are no longer penalized.

  With that groundwork in place, the core change passes IOCB_NOWAIT into
  ->update_time and returns -EAGAIN only when the file system indicates
  it would block.

  XFS implements non-blocking timestamp updates by using the new
  ->sync_lazytime and open-coding generic_update_time without the
  S_NOWAIT check, since the lazytime path through the generic helpers
  can never block in XFS"

* tag 'vfs-7.0-rc1.nonblocking_timestamps' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  xfs: enable non-blocking timestamp updates
  xfs: implement ->sync_lazytime
  fs: refactor file_update_time_flags
  fs: add support for non-blocking timestamp updates
  fs: add a ->sync_lazytime method
  fs: factor out a sync_lazytime helper
  fs: refactor ->update_time handling
  fat: cleanup the flags for fat_truncate_time
  nfs: split nfs_update_timestamps
  fs: allow error returns from generic_update_time
  fs: remove inode_update_time
2026-02-09 11:25:01 -08:00
Linus Torvalds fcb70a56f4 Merge tag 'vfs-6.19-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:

 - Fix the the buggy conversion of fuse_reverse_inval_entry() introduced
   during the creation rework

 - Disallow nfs delegation requests for directories by setting
   simple_nosetlease()

 - Require an opt-in for getting readdir flag bits outside of S_DT_MASK
   set in d_type

 - Fix scheduling delayed writeback work by only scheduling when the
   dirty time expiry interval is non-zero and cancel the delayed work if
   the interval is set to zero

 - Use rounded_jiffies_interval for dirty time work

 - Check the return value of sb_set_blocksize() for romfs

 - Wait for batched folios to be stable in __iomap_get_folio()

 - Use private naming for fuse hash size

 - Fix the stale dentry cleanup to prevent a race that causes a UAF

* tag 'vfs-6.19-rc8.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  vfs: document d_dispose_if_unused()
  fuse: shrink once after all buckets have been scanned
  fuse: clean up fuse_dentry_tree_work()
  fuse: add need_resched() before unlocking bucket
  fuse: make sure dentry is evicted if stale
  fuse: fix race when disposing stale dentries
  fuse: use private naming for fuse hash size
  writeback: use round_jiffies_relative for dirtytime_work
  iomap: wait for batched folios to be stable in __iomap_get_folio
  romfs: check sb_set_blocksize() return value
  docs: clarify that dirtytime_expire_seconds=0 disables writeback
  writeback: fix 100% CPU usage when dirtytime_expire_interval is 0
  readdir: require opt-in for d_type flags
  vboxsf: don't allow delegations to be set on directories
  ceph: don't allow delegations to be set on directories
  gfs2: don't allow delegations to be set on directories
  9p: don't allow delegations to be set on directories
  smb/client: properly disallow delegations on directories
  nfs: properly disallow delegation requests on directories
  fuse: fix conversion of fuse_reverse_inval_entry() to start_removing()
2026-01-26 09:30:48 -08:00
Joanne Koong f9a49aa302 fs/writeback: skip AS_NO_DATA_INTEGRITY mappings in wait_sb_inodes()
Above the while() loop in wait_sb_inodes(), we document that we must wait
for all pages under writeback for data integrity.  Consequently, if a
mapping, like fuse, traditionally does not have data integrity semantics,
there is no need to wait at all; we can simply skip these inodes.

This restores fuse back to prior behavior where syncs are no-ops.  This
fixes a user regression where if a system is running a faulty fuse server
that does not reply to issued write requests, this causes wait_sb_inodes()
to wait forever.

Link: https://lkml.kernel.org/r/20260105211737.4105620-2-joannelkoong@gmail.com
Fixes: 0c58a97f91 ("fuse: remove tmp folio for writebacks and internal rb tree")
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reported-by: Athul Krishna <athul.krishna.kr@protonmail.com>
Reported-by: J. Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Bernd Schubert <bschubert@ddn.com>
Tested-by: J. Neuschäfer <j.neuschaefer@gmx.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Bernd Schubert <bschubert@ddn.com>
Cc: Bonaccorso Salvatore <carnil@debian.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-19 12:30:01 -08:00
Zhao Mengmeng e93b31d081 writeback: use round_jiffies_relative for dirtytime_work
The dirtytime_work is a background housekeeping task that flushes dirty
inodes, using round_jiffies_relative() will allow kernel to batch this
work with other aligned system tasks, reducing power consumption.

Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn>
Link: https://patch.msgid.link/20260113082614.231580-1-zhaomzhao@126.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-01-14 17:11:43 +01:00
Christoph Hellwig 5cf06ea56e fs: add a ->sync_lazytime method
Allow the file system to explicitly implement lazytime syncing instead
of pigging back on generic inode dirtying.  This allows to simplify
the XFS implementation and prepares for non-blocking lazytime timestamp
updates.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260108141934.2052404-8-hch@lst.de
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-01-12 14:01:33 +01:00
Christoph Hellwig 188344c8ac fs: factor out a sync_lazytime helper
Centralize how we synchronize a lazytime update into the actual on-disk
timestamp into a single helper.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260108141934.2052404-7-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-01-12 14:01:33 +01:00
Laveesh Bansal 543467d6fe writeback: fix 100% CPU usage when dirtytime_expire_interval is 0
When vm.dirtytime_expire_seconds is set to 0, wakeup_dirtytime_writeback()
schedules delayed work with a delay of 0, causing immediate execution.
The function then reschedules itself with 0 delay again, creating an
infinite busy loop that causes 100% kworker CPU usage.

Fix by:
- Only scheduling delayed work in wakeup_dirtytime_writeback() when
  dirtytime_expire_interval is non-zero
- Cancelling the delayed work in dirtytime_interval_handler() when
  the interval is set to 0
- Adding a guard in start_dirtytime_writeback() for defensive coding

Tested by booting kernel in QEMU with virtme-ng:
- Before fix: kworker CPU spikes to ~73%
- After fix: CPU remains at normal levels
- Setting interval back to non-zero correctly resumes writeback

Fixes: a2f4870697 ("fs: make sure the timestamps for lazytime inodes eventually get written")
Cc: stable@vger.kernel.org
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220227
Signed-off-by: Laveesh Bansal <laveeshb@laveeshbansal.com>
Link: https://patch.msgid.link/20260106145059.543282-2-laveeshb@laveeshbansal.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-01-12 11:07:25 +01:00
Chen Ridong 82d7e59ea7 cgroup: switch to css_is_online() helper
Use the new css_is_online() helper that has been introduced to check css
online state, instead of testing the CSS_ONLINE flag directly. This
improves readability and centralizes the state check logic.

No functional changes intended.

Signed-off-by: Chen Ridong <chenridong@huawei.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-12-08 09:02:38 -10:00
Linus Torvalds ebaeabfa5a Merge tag 'vfs-6.19-rc1.writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull writeback updates from Christian Brauner:
 "Features:

   - Allow file systems to increase the minimum writeback chunk size.

     The relatively low minimal writeback size of 4MiB means that
     written back inodes on rotational media are switched a lot. Besides
     introducing additional seeks, this also can lead to extreme file
     fragmentation on zoned devices when a lot of files are cached
     relative to the available writeback bandwidth.

     This adds a superblock field that allows the file system to
     override the default size, and sets it to the zone size for zoned
     XFS.

   - Add logging for slow writeback when it exceeds
     sysctl_hung_task_timeout_secs. This helps identify tasks waiting
     for a long time and pinpoint potential issues. Recording the
     starting jiffies is also useful when debugging a crashed vmcore.

   - Wake up waiting tasks when finishing the writeback of a chunk

  Cleanups:

   - filemap_* writeback interface cleanups.

     Adding filemap_fdatawrite_wbc ended up being a mistake, as all but
     the original btrfs caller should be using better high level
     interfaces instead.

     This series removes all these low-level interfaces, switches btrfs
     to a more specific interface, and cleans up other too low-level
     interfaces. With this the writeback_control that is passed to the
     writeback code is only initialized in three places.

   - Remove __filemap_fdatawrite, __filemap_fdatawrite_range, and
     filemap_fdatawrite_wbc

   - Add filemap_flush_nr helper for btrfs

   - Push struct writeback_control into start_delalloc_inodes in btrfs

   - Rename filemap_fdatawrite_range_kick to filemap_flush_range

   - Stop opencoding filemap_fdatawrite_range in 9p, ocfs2, and mm

   - Make wbc_to_tag() inline and use it in fs"

* tag 'vfs-6.19-rc1.writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: Make wbc_to_tag() inline and use it in fs.
  xfs: set s_min_writeback_pages for zoned file systems
  writeback: allow the file system to override MIN_WRITEBACK_PAGES
  writeback: cleanup writeback_chunk_size
  mm: rename filemap_fdatawrite_range_kick to filemap_flush_range
  mm: remove __filemap_fdatawrite_range
  mm: remove filemap_fdatawrite_wbc
  mm: remove __filemap_fdatawrite
  mm,btrfs: add a filemap_flush_nr helper
  btrfs: push struct writeback_control into start_delalloc_inodes
  btrfs: use the local tmp_inode variable in start_delalloc_inodes
  ocfs2: don't opencode filemap_fdatawrite_range in ocfs2_journal_submit_inode_data_buffers
  9p: don't opencode filemap_fdatawrite_range in v9fs_mmap_vm_close
  mm: don't opencode filemap_fdatawrite_range in filemap_invalidate_inode
  writeback: Add logging for slow writeback (exceeds sysctl_hung_task_timeout_secs)
  writeback: Wake up waiting tasks when finishing the writeback of a chunk.
2025-12-01 09:20:51 -08:00
Mateusz Guzik 003a660730 fs: push list presence check into inode_io_list_del()
For consistency with sb routines.

ext4 is the only consumer outside of evict(). Damage-controlling it is
outside of the scope of this cleanup.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20251103230911.516866-1-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-25 10:34:49 +01:00
Mateusz Guzik 4c6b40877b fs: cosmetic fixes to lru handling
1. inode_bit_waitqueue() was somehow placed between __inode_add_lru() and
   inode_add_lru(). move it up
2. assert ->i_lock is held in __inode_add_lru instead of just claiming it is
   needed
3. s/__inode_add_lru/__inode_lru_list_add/ for consistency with itself
   (inode_lru_list_del()) and similar routines for sb and io list
   management
4. push list presence check into inode_lru_list_del(), just like sb and
   io list

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Link: https://patch.msgid.link/20251029131428.654761-2-mjguzik@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-11-25 10:34:49 +01:00
Christoph Hellwig 90db4d4441 writeback: allow the file system to override MIN_WRITEBACK_PAGES
The relatively low minimal writeback size of 4MiB means that written back
inodes on rotational media are switched a lot.  Besides introducing
additional seeks, this also can lead to extreme file fragmentation on
zoned devices when a lot of files are cached relative to the available
writeback bandwidth.

Add a superblock field that allows the file system to override the
default size.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20251017034611.651385-3-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-29 15:54:31 +01:00
Christoph Hellwig 151d0922bf writeback: cleanup writeback_chunk_size
Return the pages directly when calculated instead of first assigning
them back to a variable, and directly return for the data integrity /
tagged case instead of going through an else clause.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20251017034611.651385-2-hch@lst.de
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-29 15:54:31 +01:00
Christoph Hellwig 1bcb413d0c mm: remove filemap_fdatawrite_wbc
Replace filemap_fdatawrite_wbc, which exposes a writeback_control to the
callers with a filemap_writeback helper that takes all the possible
arguments and declares the writeback_control itself.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20251024080431.324236-9-hch@lst.de
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-29 15:50:41 +01:00
Julian Sun d6e6215907 writeback: Add logging for slow writeback (exceeds sysctl_hung_task_timeout_secs)
When a writeback work lasts for sysctl_hung_task_timeout_secs, we want
to identify that there are tasks waiting for a long time-this helps us
pinpoint potential issues.

Additionally, recording the starting jiffies is useful when debugging a
crashed vmcore.

Signed-off-by: Julian Sun <sunjunchao@bytedance.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-20 20:22:39 +02:00
Julian Sun 1888635532 writeback: Wake up waiting tasks when finishing the writeback of a chunk.
Writing back a large number of pages can take a lots of time.
This issue is exacerbated when the underlying device is slow or
subject to block layer rate limiting, which in turn triggers
unexpected hung task warnings.

We can trigger a wake-up once a chunk has been written back and the
waiting time for writeback exceeds half of
sysctl_hung_task_timeout_secs.
This action allows the hung task detector to be aware of the writeback
progress, thereby eliminating these unexpected hung task warnings.

This patch has passed the xfstests 'check -g quick' test based on ext4,
with no additional failures introduced.

Signed-off-by: Julian Sun <sunjunchao@bytedance.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-20 20:22:39 +02:00
Mateusz Guzik b4dbfd8653 Coccinelle-based conversion to use ->i_state accessors
All places were patched by coccinelle with the default expecting that
->i_lock is held, afterwards entries got fixed up by hand to use
unlocked variants as needed.

The script:
@@
expression inode, flags;
@@

- inode->i_state & flags
+ inode_state_read(inode) & flags

@@
expression inode, flags;
@@

- inode->i_state &= ~flags
+ inode_state_clear(inode, flags)

@@
expression inode, flag1, flag2;
@@

- inode->i_state &= ~flag1 & ~flag2
+ inode_state_clear(inode, flag1 | flag2)

@@
expression inode, flags;
@@

- inode->i_state |= flags
+ inode_state_set(inode, flags)

@@
expression inode, flags;
@@

- inode->i_state = flags
+ inode_state_assign(inode, flags)

@@
expression inode, flags;
@@

- flags = inode->i_state
+ flags = inode_state_read(inode)

@@
expression inode, flags;
@@

- READ_ONCE(inode->i_state) & flags
+ inode_state_read(inode) & flags

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-20 20:22:26 +02:00
Mateusz Guzik cb5db358ab fs: spell out fenced ->i_state accesses with explicit smp_wmb/smp_rmb
The incomming helpers don't ship with _release/_acquire variants, for
the time being anyway.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-10-20 20:22:26 +02:00
Linus Torvalds 263e777ee3 Merge tag 'vfs-6.18-rc1.writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs writeback updates from Christian Brauner:
 "This contains work adressing lockups reported by users when a systemd
  unit reading lots of files from a filesystem mounted with the lazytime
  mount option exits.

  With the lazytime mount option enabled we can be switching many dirty
  inodes on cgroup exit to the parent cgroup. The numbers observed in
  practice when systemd slice of a large cron job exits can easily reach
  hundreds of thousands or millions.

  The logic in inode_do_switch_wbs() which sorts the inode into
  appropriate place in b_dirty list of the target wb however has linear
  complexity in the number of dirty inodes thus overall time complexity
  of switching all the inodes is quadratic leading to workers being
  pegged for hours consuming 100% of the CPU and switching inodes to the
  parent wb.

  Simple reproducer of the issue:

      FILES=10000
      # Filesystem mounted with lazytime mount option
      MNT=/mnt/
      echo "Creating files and switching timestamps"
      for (( j = 0; j < 50; j ++ )); do
          mkdir $MNT/dir$j
          for (( i = 0; i < $FILES; i++ )); do
              echo "foo" >$MNT/dir$j/file$i
          done
          touch -a -t 202501010000 $MNT/dir$j/file*
      done
      wait
      echo "Syncing and flushing"
      sync
      echo 3 >/proc/sys/vm/drop_caches

      echo "Reading all files from a cgroup"
      mkdir /sys/fs/cgroup/unified/mycg1 || exit
      echo $$ >/sys/fs/cgroup/unified/mycg1/cgroup.procs || exit
      for (( j = 0; j < 50; j ++ )); do
          cat /mnt/dir$j/file* >/dev/null &
      done
      wait
      echo "Switching wbs"
      # Now rmdir the cgroup after the script exits

  This can be solved by:

   - Avoiding contention on the wb->list_lock when switching inodes by
     running a single work item per wb and managing a queue of items
     switching to the wb

   - Allowing rescheduling when switching inodes over to a different
     cgroup to avoid softlockups

   - Maintaining the b_dirty list ordering instead of sorting it"

* tag 'vfs-6.18-rc1.writeback' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  writeback: Add tracepoint to track pending inode switches
  writeback: Avoid excessively long inode switching times
  writeback: Avoid softlockup when switching many inodes
  writeback: Avoid contention on wb->list_lock when switching inodes
2025-09-29 11:34:40 -07:00
Linus Torvalds b786405685 Merge tag 'vfs-6.18-rc1.workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs workqueue updates from Christian Brauner:
 "This contains various workqueue changes affecting the filesystem
  layer.

  Currently if a user enqueue a work item using schedule_delayed_work()
  the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
  WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies
  to schedule_work() that is using system_wq and queue_work(), that
  makes use again of WORK_CPU_UNBOUND.

  This replaces the use of system_wq and system_unbound_wq. system_wq is
  a per-CPU workqueue which isn't very obvious from the name and
  system_unbound_wq is to be used when locality is not required.

  So this renames system_wq to system_percpu_wq, and system_unbound_wq
  to system_dfl_wq.

  This also adds a new WQ_PERCPU flag to allow the fs subsystem users to
  explicitly request the use of per-CPU behavior. Both WQ_UNBOUND and
  WQ_PERCPU flags coexist for one release cycle to allow callers to
  transition their calls. WQ_UNBOUND will be removed in a next release
  cycle"

* tag 'vfs-6.18-rc1.workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: WQ_PERCPU added to alloc_workqueue users
  fs: replace use of system_wq with system_percpu_wq
  fs: replace use of system_unbound_wq with system_dfl_wq
2025-09-29 10:27:17 -07:00
Linus Torvalds 56e7b31071 Merge tag 'vfs-6.18-rc1.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs inode updates from Christian Brauner:
 "This contains a series I originally wrote and that Eric brought over
  the finish line. It moves out the i_crypt_info and i_verity_info
  pointers out of 'struct inode' and into the fs-specific part of the
  inode.

  So now the few filesytems that actually make use of this pay the price
  in their own private inode storage instead of forcing it upon every
  user of struct inode.

  The pointer for the crypt and verity info is simply found by storing
  an offset to its address in struct fsverity_operations and struct
  fscrypt_operations. This shrinks struct inode by 16 bytes.

  I hope to move a lot more out of it in the future so that struct inode
  becomes really just about very core stuff that we need, much like
  struct dentry and struct file, instead of the dumping ground it has
  become over the years.

  On top of this are a various changes associated with the ongoing inode
  lifetime handling rework that multiple people are pushing forward:

   - Stop accessing inode->i_count directly in f2fs and gfs2. They
     simply should use the __iget() and iput() helpers

   - Make the i_state flags an enum

   - Rework the iput() logic

     Currently, if we are the last iput, and we have the I_DIRTY_TIME
     bit set, we will grab a reference on the inode again and then mark
     it dirty and then redo the put. This is to make sure we delay the
     time update for as long as possible

     We can rework this logic to simply dec i_count if it is not 1, and
     if it is do the time update while still holding the i_count
     reference

     Then we can replace the atomic_dec_and_lock with locking the
     ->i_lock and doing atomic_dec_and_test, since we did the
     atomic_add_unless above

   - Add an icount_read() helper and convert everyone that accesses
     inode->i_count directly for this purpose to use the helper

   - Expand dump_inode() to dump more information about an inode helping
     in debugging

   - Add some might_sleep() annotations to iput() and associated
     helpers"

* tag 'vfs-6.18-rc1.inode' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  fs: add might_sleep() annotation to iput() and more
  fs: expand dump_inode()
  inode: fix whitespace issues
  fs: add an icount_read helper
  fs: rework iput logic
  fs: make the i_state flags an enum
  fs: stop accessing ->i_count directly in f2fs and gfs2
  fsverity: check IS_VERITY() in fsverity_cleanup_inode()
  fs: remove inode::i_verity_info
  btrfs: move verity info pointer to fs-specific part of inode
  f2fs: move verity info pointer to fs-specific part of inode
  ext4: move verity info pointer to fs-specific part of inode
  fsverity: add support for info in fs-specific part of inode
  fs: remove inode::i_crypt_info
  ceph: move crypt info pointer to fs-specific part of inode
  ubifs: move crypt info pointer to fs-specific part of inode
  f2fs: move crypt info pointer to fs-specific part of inode
  ext4: move crypt info pointer to fs-specific part of inode
  fscrypt: add support for info in fs-specific part of inode
  fscrypt: replace raw loads of info pointer with helper function
2025-09-29 09:42:30 -07:00
Linus Torvalds b7ce6fa90f Merge tag 'vfs-6.18-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
 "This contains the usual selections of misc updates for this cycle.

  Features:

   - Add "initramfs_options" parameter to set initramfs mount options.
     This allows to add specific mount options to the rootfs to e.g.,
     limit the memory size

   - Add RWF_NOSIGNAL flag for pwritev2()

     Add RWF_NOSIGNAL flag for pwritev2. This flag prevents the SIGPIPE
     signal from being raised when writing on disconnected pipes or
     sockets. The flag is handled directly by the pipe filesystem and
     converted to the existing MSG_NOSIGNAL flag for sockets

   - Allow to pass pid namespace as procfs mount option

     Ever since the introduction of pid namespaces, procfs has had very
     implicit behaviour surrounding them (the pidns used by a procfs
     mount is auto-selected based on the mounting process's active
     pidns, and the pidns itself is basically hidden once the mount has
     been constructed)

     This implicit behaviour has historically meant that userspace was
     required to do some special dances in order to configure the pidns
     of a procfs mount as desired. Examples include:

     * In order to bypass the mnt_too_revealing() check, Kubernetes
       creates a procfs mount from an empty pidns so that user
       namespaced containers can be nested (without this, the nested
       containers would fail to mount procfs)

       But this requires forking off a helper process because you cannot
       just one-shot this using mount(2)

     * Container runtimes in general need to fork into a container
       before configuring its mounts, which can lead to security issues
       in the case of shared-pidns containers (a privileged process in
       the pidns can interact with your container runtime process)

       While SUID_DUMP_DISABLE and user namespaces make this less of an
       issue, the strict need for this due to a minor uAPI wart is kind
       of unfortunate

       Things would be much easier if there was a way for userspace to
       just specify the pidns they want. So this pull request contains
       changes to implement a new "pidns" argument which can be set
       using fsconfig(2):

           fsconfig(procfd, FSCONFIG_SET_FD, "pidns", NULL, nsfd);
           fsconfig(procfd, FSCONFIG_SET_STRING, "pidns", "/proc/self/ns/pid", 0);

       or classic mount(2) / mount(8):

           // mount -t proc -o pidns=/proc/self/ns/pid proc /tmp/proc
           mount("proc", "/tmp/proc", "proc", MS_..., "pidns=/proc/self/ns/pid");

  Cleanups:

   - Remove the last references to EXPORT_OP_ASYNC_LOCK

   - Make file_remove_privs_flags() static

   - Remove redundant __GFP_NOWARN when GFP_NOWAIT is used

   - Use try_cmpxchg() in start_dir_add()

   - Use try_cmpxchg() in sb_init_done_wq()

   - Replace offsetof() with struct_size() in ioctl_file_dedupe_range()

   - Remove vfs_ioctl() export

   - Replace rwlock() with spinlock in epoll code as rwlock causes
     priority inversion on preempt rt kernels

   - Make ns_entries in fs/proc/namespaces const

   - Use a switch() statement() in init_special_inode() just like we do
     in may_open()

   - Use struct_size() in dir_add() in the initramfs code

   - Use str_plural() in rd_load_image()

   - Replace strcpy() with strscpy() in find_link()

   - Rename generic_delete_inode() to inode_just_drop() and
     generic_drop_inode() to inode_generic_drop()

   - Remove unused arguments from fcntl_{g,s}et_rw_hint()

  Fixes:

   - Document @name parameter for name_contains_dotdot() helper

   - Fix spelling mistake

   - Always return zero from replace_fd() instead of the file descriptor
     number

   - Limit the size for copy_file_range() in compat mode to prevent a
     signed overflow

   - Fix debugfs mount options not being applied

   - Verify the inode mode when loading it from disk in minixfs

   - Verify the inode mode when loading it from disk in cramfs

   - Don't trigger automounts with RESOLVE_NO_XDEV

     If openat2() was called with RESOLVE_NO_XDEV it didn't traverse
     through automounts, but could still trigger them

   - Add FL_RECLAIM flag to show_fl_flags() macro so it appears in
     tracepoints

   - Fix unused variable warning in rd_load_image() on s390

   - Make INITRAMFS_PRESERVE_MTIME depend on BLK_DEV_INITRD

   - Use ns_capable_noaudit() when determining net sysctl permissions

   - Don't call path_put() under namespace semaphore in listmount() and
     statmount()"

* tag 'vfs-6.18-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (38 commits)
  fcntl: trim arguments
  listmount: don't call path_put() under namespace semaphore
  statmount: don't call path_put() under namespace semaphore
  pid: use ns_capable_noaudit() when determining net sysctl permissions
  fs: rename generic_delete_inode() and generic_drop_inode()
  init: INITRAMFS_PRESERVE_MTIME should depend on BLK_DEV_INITRD
  initramfs: Replace strcpy() with strscpy() in find_link()
  initrd: Use str_plural() in rd_load_image()
  initramfs: Use struct_size() helper to improve dir_add()
  initrd: Fix unused variable warning in rd_load_image() on s390
  fs: use the switch statement in init_special_inode()
  fs/proc/namespaces: make ns_entries const
  filelock: add FL_RECLAIM to show_fl_flags() macro
  eventpoll: Replace rwlock with spinlock
  selftests/proc: add tests for new pidns APIs
  procfs: add "pidns" mount option
  pidns: move is-ancestor logic to helper
  openat2: don't trigger automounts with RESOLVE_NO_XDEV
  namei: move cross-device check to __traverse_mounts
  namei: remove LOOKUP_NO_XDEV check from handle_mounts
  ...
2025-09-29 09:03:07 -07:00