[PATCH v5 0/7] block atomic writes for xfs

[John Garry]

This series expands atomic write support to filesystems, specifically
XFS. Extent alignment is based on new feature forcealign.

Flag FS_XFLAG_ATOMICWRITES is added as an enabling flag for atomic writes.

XFS can be formatted for atomic writes as follows:
mkfs.xfs -i forcealign=1 -d extsize=16384 -d atomic-writes=1  /dev/sda

atomic-writes=1 just enables atomic writes in the SB, but does not auto-
enable atomic writes for each file.

Support can be enabled through xfs_io command:
$xfs_io -c "lsattr -v" filename
[extsize, force-align]
$xfs_io -c "extsize" filename
[16384] filename
$xfs_io -c "chattr +W" filename
$xfs_io -c "lsattr -v" filename
[extsize, force-align, atomic-writes] filename
$xfs_io -c statx filename
...
stat.stx_atomic_write_unit_min = 4096
stat.stx_atomic_write_unit_max = 16384
stat.stx_atomic_write_segments_max = 1
...


New in this series is a re-work of the iomap bio creation, in that we now
produce a single bio, which may cover multiple extents. Extent-based
zeroing is dropped.

Baseline is following series:
https://lore.kernel.org/linux-xfs/20240813163638.3751939-1-john.g.garry@xxxxxxxxxx/T/#t

Basic xfsprogs support at:
https://github.com/johnpgarry/xfsprogs-dev/tree/forcealign_and_atomicwrites_for_v4_xfs_block_atomic_writes

Patches for this series can be found at:
https://github.com/johnpgarry/linux/tree/atomic-writes-v6.11-fs-v5

Changes since v4:
- Drop iomap extent-based zeroing and use single bio to cover multiple
  extents
- Move forcealign to another series
- Various change in ioctl, sb, inode validation
- Add patch to tweak generic_atomic_write_valid() API

Changes since v3:
https://lore.kernel.org/linux-xfs/20240429174746.2132161-1-john.g.garry@xxxxxxxxxx/T/#m9424b3cd1ccfde795d04474fdb4456520b6b4242
- Only enforce forcealign extsize is power-of-2 for atomic writes
- Re-org some validation code
- Fix xfs_bmap_process_allocated_extent() for forcealign
- Support iomap->io_block_size and make each fs support it
- Add !power-of-2 iomap support for io_block_size
- Make iomap dio iter handle atomic write failure properly by zeroing the
  remaining io_block_size

John Garry (7):
  block/fs: Pass an iocb to generic_atomic_write_valid()
  fs: Export generic_atomic_write_valid()
  fs: iomap: Atomic write support
  xfs: Support FS_XFLAG_ATOMICWRITES for forcealign
  xfs: Support atomic write for statx
  xfs: Validate atomic writes
  xfs: Support setting FMODE_CAN_ATOMIC_WRITE

 block/fops.c                   |   8 +--
 fs/iomap/direct-io.c           | 122 ++++++++++++++++++++++++++++-----
 fs/iomap/trace.h               |   3 +-
 fs/read_write.c                |   5 +-
 fs/xfs/libxfs/xfs_format.h     |  11 ++-
 fs/xfs/libxfs/xfs_inode_buf.c  |  52 ++++++++++++++
 fs/xfs/libxfs/xfs_inode_util.c |   4 ++
 fs/xfs/libxfs/xfs_sb.c         |   2 +
 fs/xfs/xfs_buf.c               |  15 +++-
 fs/xfs/xfs_buf.h               |   4 +-
 fs/xfs/xfs_buf_mem.c           |   2 +-
 fs/xfs/xfs_file.c              |  27 +++++++-
 fs/xfs/xfs_inode.h             |   5 ++
 fs/xfs/xfs_ioctl.c             |  52 ++++++++++++++
 fs/xfs/xfs_iops.c              |  28 ++++++++
 fs/xfs/xfs_mount.h             |   2 +
 fs/xfs/xfs_super.c             |  12 ++++
 include/linux/fs.h             |   2 +-
 include/linux/iomap.h          |   1 +
 include/uapi/linux/fs.h        |   1 +
 20 files changed, 325 insertions(+), 33 deletions(-)

-- 
2.31.1