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Message-ID: <20260206-vfs-misc-v70-be6f713f9fa9@brauner>
Date: Fri, 6 Feb 2026 17:50:08 +0100
From: Christian Brauner <brauner@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Christian Brauner <brauner@...nel.org>,
linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [GIT PULL 12/12 for v7.0] vfs misc
Hey Linus,
/* Summary */
This contains a mix of VFS cleanups, performance improvements, API fixes,
documentation, and a deprecation notice.
Scalability and performance:
- Rework pid allocation to only take pidmap_lock once instead of twice
during alloc_pid(), improving thread creation/teardown throughput by
10-16% depending on false-sharing luck. Pad the namespace refcount to
reduce false-sharing.
- Track file lock presence via a flag in ->i_opflags instead of reading
->i_flctx, avoiding false-sharing with ->i_readcount on open/close
hot paths. Measured 4-16% improvement on 24-core open-in-a-loop
benchmarks.
- Use a consume fence in locks_inode_context() to match the
store-release/load-consume idiom, eliminating a hardware fence on
some architectures.
- Annotate cdev_lock with __cacheline_aligned_in_smp to prevent
false-sharing.
- Remove a redundant DCACHE_MANAGED_DENTRY check in
__follow_mount_rcu() that never fires since the caller already
verifies it, eliminating a 100% mispredicted branch.
- Fix a 100% mispredicted likely() hint in devcgroup_inode_permission()
that became wrong after a prior code reorder.
Bug fixes and correctness:
- Make insert_inode_locked() wait for inode destruction instead of
skipping, fixing a corner case where two matching inodes could exist
in the hash.
- Move f_mode initialization before file_ref_init() in alloc_file() to
respect the SLAB_TYPESAFE_BY_RCU ordering contract.
- Add a WARN_ON_ONCE guard in try_to_free_buffers() for folios with no
buffers attached, preventing a null pointer dereference when
AS_RELEASE_ALWAYS is set but no release_folio op exists.
- Fix select restart_block to store end_time as timespec64, avoiding
truncation of tv_sec on 32-bit architectures.
- Make dump_inode() use get_kernel_nofault() to safely access inode and
superblock fields, matching the dump_mapping() pattern.
API modernization:
- Make posix_acl_to_xattr() allocate the buffer internally since every
single caller was doing it anyway. Reduces boilerplate and
unnecessary error checking across ~15 filesystems.
- Replace deprecated simple_strtoul() with kstrtoul() for the
ihash_entries, dhash_entries, mhash_entries, and mphash_entries boot
parameters, adding proper error handling.
- Convert chardev code to use guard(mutex) and __free(kfree) cleanup
patterns.
- Replace min_t() with min() or umin() in VFS code to avoid silently
truncating unsigned long to unsigned int.
- Gate LOOKUP_RCU assertions behind CONFIG_DEBUG_VFS since callers
already check the flag.
Deprecation:
- Begin deprecating legacy BSD process accounting (acct(2)). The
interface has numerous footguns and better alternatives exist (eBPF).
Documentation:
- Fix and complete kernel-doc for struct export_operations, removing
duplicated documentation between ReST and source.
- Fix kernel-doc warnings for __start_dirop() and ilookup5_nowait().
Testing:
- Add a kunit test for initramfs cpio handling of entries with
filesize > PATH_MAX.
Misc:
- Add missing <linux/init_task.h> include in fs_struct.c.
/* Testing */
gcc (Debian 14.2.0-19) 14.2.0
Debian clang version 19.1.7 (3+b1)
No build failures or warnings were observed.
/* Conflicts */
Merge conflicts with mainline
=============================
No known conflicts.
Merge conflicts with other trees
================================
The following changes since commit 8f0b4cce4481fb22653697cced8d0d04027cb1e8:
Linux 6.19-rc1 (2025-12-14 16:05:07 +1200)
are available in the Git repository at:
git@...olite.kernel.org:pub/scm/linux/kernel/git/vfs/vfs tags/vfs-7.0-rc1.misc
for you to fetch changes up to 6cbfdf89470ef3c2110f376a507d135e7a7a7378:
posix_acl: make posix_acl_to_xattr() alloc the buffer (2026-01-16 10:51:12 +0100)
----------------------------------------------------------------
vfs-7.0-rc1.misc
Please consider pulling these changes from the signed vfs-7.0-rc1.misc tag.
Thanks!
Christian
----------------------------------------------------------------
Amir Goldstein (1):
fs: move initializing f_mode before file_ref_init()
André Almeida (4):
exportfs: Fix kernel-doc output for get_name()
exportfs: Mark struct export_operations functions at kernel-doc
exportfs: Complete kernel-doc for struct export_operations
docs: exportfs: Use source code struct documentation
Bagas Sanjaya (2):
fs: Describe @isnew parameter in ilookup5_nowait()
VFS: fix __start_dirop() kernel-doc warnings
Ben Dooks (1):
fs: add <linux/init_task.h> for 'init_fs'
Breno Leitao (2):
fs/namei: Remove redundant DCACHE_MANAGED_DENTRY check in __follow_mount_rcu
device_cgroup: remove branch hint after code refactor
Christian Brauner (3):
Merge patch series "further damage-control lack of clone scalability"
Merge patch series "vfs kernel-doc fixes for 6.19"
Merge patch series "exportfs: Some kernel-doc fixes"
David Disseldorp (1):
initramfs_test: kunit test for cpio.filesize > PATH_MAX
David Laight (1):
fs: use min() or umin() instead of min_t()
Deepakkumar Karn (1):
fs/buffer: add alert in try_to_free_buffers() for folios without buffers
Jeff Layton (1):
acct(2): begin the deprecation of legacy BSD process accounting
Mateusz Guzik (7):
fs: annotate cdev_lock with __cacheline_aligned_in_smp
ns: pad refcount
filelock: use a consume fence in locks_inode_context()
pid: only take pidmap_lock once on alloc
fs: track the inode having file locks with a flag in ->i_opflags
fs: only assert on LOOKUP_RCU when built with CONFIG_DEBUG_VFS
fs: make insert_inode_locked() wait for inode destruction
Miklos Szeredi (1):
posix_acl: make posix_acl_to_xattr() alloc the buffer
Thomas Weißschuh (1):
select: store end_time as timespec64 in restart block
Thorsten Blum (3):
fs: Replace simple_strtoul with kstrtoul in set_ihash_entries
dcache: Replace simple_strtoul with kstrtoul in set_dhash_entries
namespace: Replace simple_strtoul with kstrtoul to parse boot params
Yuto Ohnuki (1):
fs: improve dump_inode() to safely access inode fields
chen zhang (1):
chardev: Switch to guard(mutex) and __free(kfree)
Documentation/filesystems/nfs/exporting.rst | 42 ++-------
fs/9p/acl.c | 16 +---
fs/btrfs/acl.c | 10 +--
fs/buffer.c | 6 +-
fs/ceph/acl.c | 50 +++++------
fs/char_dev.c | 19 ++--
fs/dcache.c | 5 +-
fs/exec.c | 2 +-
fs/ext4/mballoc.c | 3 +-
fs/ext4/resize.c | 2 +-
fs/ext4/super.c | 2 +-
fs/fat/dir.c | 4 +-
fs/fat/file.c | 3 +-
fs/file_table.c | 10 +--
fs/fs_struct.c | 1 +
fs/fuse/acl.c | 12 +--
fs/fuse/dev.c | 2 +-
fs/fuse/file.c | 8 +-
fs/gfs2/acl.c | 13 +--
fs/inode.c | 96 ++++++++++++--------
fs/jfs/acl.c | 9 +-
fs/locks.c | 14 ++-
fs/namei.c | 11 ++-
fs/namespace.c | 10 +--
fs/ntfs3/xattr.c | 6 +-
fs/orangefs/acl.c | 8 +-
fs/posix_acl.c | 21 ++---
fs/select.c | 12 +--
fs/splice.c | 2 +-
include/linux/device_cgroup.h | 2 +-
include/linux/exportfs.h | 33 ++++---
include/linux/filelock.h | 18 +++-
include/linux/fs.h | 1 +
include/linux/ns/ns_common_types.h | 4 +-
include/linux/posix_acl_xattr.h | 5 +-
include/linux/restart_block.h | 4 +-
init/Kconfig | 7 +-
init/initramfs_test.c | 48 ++++++++++
kernel/pid.c | 131 ++++++++++++++++++----------
39 files changed, 357 insertions(+), 295 deletions(-)
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