This is v2 of atomic write enablement on ext4 for DIO. I have split this series as discussed in v1 [1], so this only enables atomic writes to a single fsblock. That means for now this gets only enabled on bs < ps systems on ext4. Enablement of atomic writes for bigalloc (multi-fsblock support) is still under discussion and may require general consensus within the filesystem community [1]. This series adds the base feature support to enable atomic writes in direct-io path for ext4. We advertise the minimum and the maximum atomic write unit sizes via statx on a regular file. This series allows users to utilize atomic write support using - 1. on bs < ps systems via - mkfs.ext4 -F -b 16384 /dev/sda This can then be utilized using - xfs_io -fdc "pwrite -V 1 -A -b16k 0 16k" /mnt/f1 This is built on top of John's DIO atomic write series for XFS [2]. The VFS and block layer enablement for atomic writes were merged already. [1]: https://lore.kernel.org/linux-ext4/87jzdvmqfz.fsf@xxxxxxxxx [2]: https://lore.kernel.org/linux-xfs/20241019125113.369994-1-john.g.garry@xxxxxxxxxx/ Changelogs: =========== PATCH -> PATCH v2: - addressed review comments from John and Darrick. - renamed ext4_sb_info variables names: fs_awu* -> s_awu* - [PATCH]: https://lore.kernel.org/linux-ext4/cover.1729825985.git.ritesh.list@xxxxxxxxx/ RFC -> PATCH: - Dropped RFC tag - Last RFC was posted a while ago but back then a lot of VFS and block layer interfaces were still not merged. Those are now merged, thanks to John and everyone else. - [RFC] - https://lore.kernel.org/linux-ext4/cover.1709356594.git.ritesh.list@xxxxxxxxx/ Ritesh Harjani (IBM) (4): ext4: Add statx support for atomic writes ext4: Check for atomic writes support in write iter ext4: Support setting FMODE_CAN_ATOMIC_WRITE ext4: Do not fallback to buffered-io for DIO atomic write fs/ext4/ext4.h | 9 +++++++++ fs/ext4/file.c | 29 ++++++++++++++++++++++++++++- fs/ext4/inode.c | 14 ++++++++++++++ fs/ext4/super.c | 31 +++++++++++++++++++++++++++++++ 4 files changed, 82 insertions(+), 1 deletion(-) -- 2.46.0
