| From: |
| Christoph Hellwig <hch-AT-lst.de> |
| To: |
| Christian Brauner <brauner-AT-kernel.org> |
| Subject: |
| re-enable IOCB_NOWAIT writes to files v6 |
| Date: |
| Thu, 08 Jan 2026 15:19:00 +0100 |
| Message-ID: |
| <20260108141934.2052404-1-hch@lst.de> |
| Cc: |
| Al Viro <viro-AT-zeniv.linux.org.uk>, David Sterba <dsterba-AT-suse.com>, Jan Kara <jack-AT-suse.cz>, Mike Marshall <hubcap-AT-omnibond.com>, Martin Brandenburg <martin-AT-omnibond.com>, Carlos Maiolino <cem-AT-kernel.org>, Stefan Roesch <shr-AT-fb.com>, Jeff Layton <jlayton-AT-kernel.org>, OGAWA Hirofumi <hirofumi-AT-mail.parknet.co.jp>, Trond Myklebust <trondmy-AT-kernel.org>, Anna Schumaker <anna-AT-kernel.org>, linux-kernel-AT-vger.kernel.org, linux-btrfs-AT-vger.kernel.org, linux-fsdevel-AT-vger.kernel.org, gfs2-AT-lists.linux.dev, io-uring-AT-vger.kernel.org, devel-AT-lists.orangefs.org, linux-unionfs-AT-vger.kernel.org, linux-mtd-AT-lists.infradead.org, linux-xfs-AT-vger.kernel.org, linux-nfs-AT-vger.kernel.org |
Hi all,
commit 66fa3cedf16a ("fs: Add async write file modification handling.")
effectively disabled IOCB_NOWAIT writes as timestamp updates currently
always require blocking, and the modern timestamp resolution means we
always update timestamps. This leads to a lot of context switches from
applications using io_uring to submit file writes, making it often worse
than using the legacy aio code that is not using IOCB_NOWAIT.
This series allows non-blocking updates for lazytime if the file system
supports it, and adds that support for XFS.
Changes since v5:
- sample ctime before calling inode_set_ctime_current
- fix a mild bisection hazard in fat
Changes since v4:
- replace the S_* flags with an enum indicating either access or
modification time updates to make the logic less fragile and to
fix a bug in the previous version
Changes since v3:
- fix was_dirty_time handling in __mark_inode_dirty for the racy flag
update case
- refactor inode_update_timestamps to make the lazytime vs blocking
logical more clear
- allow non-blocking timestamp updates for fat
Changes since v2:
- drop patches merged upstream
- adjust for the inode state accesors
- keep a check in __writeback_single_inode instead of exercising
potentially undefined behavior
- more spelling fixes
Changes since v1:
- more regular numbering of the S_* flags
- fix XFS to actually not block
- don't ignore the generic_update_time return value in
file_update_time_flags
- fix the sync_lazytime return value
- fix an out of data comment in btrfs
- fix a race that would update i_version before returning -EAGAIN in XFS
Diffstat:
Documentation/filesystems/locking.rst | 2
Documentation/filesystems/vfs.rst | 6 +
fs/btrfs/inode.c | 8 +-
fs/fs-writeback.c | 33 +++++++---
fs/gfs2/inode.c | 6 +
fs/inode.c | 111 +++++++++++++++++++++-------------
fs/internal.h | 3
fs/nfs/inode.c | 4 -
fs/orangefs/inode.c | 5 +
fs/overlayfs/inode.c | 2
fs/sync.c | 4 -
fs/ubifs/file.c | 13 ++-
fs/xfs/xfs_iops.c | 34 +++++++++-
fs/xfs/xfs_super.c | 29 --------
include/linux/fs.h | 27 ++++++--
include/trace/events/writeback.h | 6 -
16 files changed, 182 insertions(+), 111 deletions(-)
