[GIT PULL 03/12 for v7.0] vfs nonblocking_timestamps

[Christian Brauner]

Hey Linus,

/* Summary */

This contains the changes to support non-blocking timestamp updates.

Since 66fa3cedf16a ("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 series 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.

/* 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@xxxxxxxxxxxxxxxxxxx:pub/scm/linux/kernel/git/vfs/vfs tags/vfs-7.0-rc1.nonblocking_timestamps

for you to fetch changes up to 77ef2c3ff5916d358c436911ca6a961060709f04:

  Merge patch series "re-enable IOCB_NOWAIT writes to files v6" (2026-01-12 14:01:42 +0100)

----------------------------------------------------------------
vfs-7.0-rc1.nonblocking_timestamps

Please consider pulling these changes from the signed vfs-7.0-rc1.nonblocking_timestamps tag.

Thanks!
Christian

----------------------------------------------------------------
Christian Brauner (1):
      Merge patch series "re-enable IOCB_NOWAIT writes to files v6"

Christoph Hellwig (11):
      fs: remove inode_update_time
      fs: allow error returns from generic_update_time
      nfs: split nfs_update_timestamps
      fat: cleanup the flags for fat_truncate_time
      fs: refactor ->update_time handling
      fs: factor out a sync_lazytime helper
      fs: add a ->sync_lazytime method
      fs: add support for non-blocking timestamp updates
      fs: refactor file_update_time_flags
      xfs: implement ->sync_lazytime
      xfs: enable non-blocking timestamp updates

 Documentation/filesystems/locking.rst |   5 +-
 Documentation/filesystems/vfs.rst     |   9 +-
 fs/bad_inode.c                        |   3 +-
 fs/btrfs/inode.c                      |  13 ++-
 fs/fat/dir.c                          |   2 +-
 fs/fat/fat.h                          |  11 +-
 fs/fat/file.c                         |  14 +--
 fs/fat/inode.c                        |   2 +-
 fs/fat/misc.c                         |  59 ++++------
 fs/fat/namei_msdos.c                  |  13 +--
 fs/fat/namei_vfat.c                   |   9 +-
 fs/fs-writeback.c                     |  33 ++++--
 fs/gfs2/inode.c                       |   9 +-
 fs/inode.c                            | 202 ++++++++++++++++++----------------
 fs/internal.h                         |   3 +-
 fs/nfs/inode.c                        |  37 +++----
 fs/orangefs/inode.c                   |  29 +++--
 fs/orangefs/orangefs-kernel.h         |   3 +-
 fs/overlayfs/inode.c                  |   7 +-
 fs/overlayfs/overlayfs.h              |   3 +-
 fs/sync.c                             |   4 +-
 fs/ubifs/file.c                       |  28 ++---
 fs/ubifs/ubifs.h                      |   3 +-
 fs/xfs/xfs_iops.c                     |  49 ++++++---
 fs/xfs/xfs_super.c                    |  29 -----
 include/linux/fs.h                    |  30 +++--
 include/trace/events/writeback.h      |   6 -
 27 files changed, 325 insertions(+), 290 deletions(-)