fs-verity support for XFS with post EOF merkle tree

Hi all,

This patchset adds fs-verity support for XFS. This version store merkle
tree beyond end of the file, similar as ext4 does it.

The first two patches introduce new iomap_read/write interface in iomap.
The reasons are:
- it is not bound by EOF,
- the iomap_read_region() also allocates folio and returns it to caller.

Then follows changes to the fs-verity core, per-filesystem workqueue,
iomap integration. These are mostly unchanged from previous patchsets.

The iomap read path has a bit of a fs-verity only zeroing logic for the
case when tree block size, fs block size and page size differ. As tree is
contiguous region of memory I just zero the tail of the tree region.

Preallocations. I just disabled preallocations by setting allocation
size to zero for Merkle tree data. This should not be a problem as these
files are read-only and in stable state when we get to Merkle tree
writing. It would be nice to allocate tree size on first write, but I
haven't got to it yet.

The tree is read by iomap into page cache at offset 1 << 53. This seems
to be far enough to handle any supported file size.

Testing. The -g verity is passing for 1k and 4k with/without quota, the
tests include different merkle tree block size.

I plan to look into readahead and whole tree allocation on first write
and xfsprogs requires a bit more work.

Feedback is welcomed :)

xfsprogs:
https://github.com/alberand/xfsprogs/tree/b4/fsverity

xfstests:
https://github.com/alberand/xfstests/tree/b4/fsverity

Cc: fsverity@lists.linux.dev
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-xfs@vger.kernel.org

Cc: david@fromorbit.com
Cc: djwong@kernel.org
Cc: ebiggers@kernel.org
Cc: hch@lst.de

[RFC] Directly mapped xattr data & fs-verity
[1]: https://lore.kernel.org/linux-xfs/20241229133350.1192387-...

---
Andrey Albershteyn (19):
      iomap: add iomap_writepages_unbound() to write beyond EOF
      iomap: introduce iomap_read/write_region interface
      fs: add FS_XFLAG_VERITY for verity files
      fsverity: add per-sb workqueue for post read processing
      fsverity: add tracepoints
      iomap: integrate fs-verity verification into iomap's read path
      xfs: add attribute type for fs-verity
      xfs: add fs-verity ro-compat flag
      xfs: add inode on-disk VERITY flag
      xfs: initialize fs-verity on file open and cleanup on inode destruction
      xfs: don't allow to enable DAX on fs-verity sealed inode
      xfs: disable direct read path for fs-verity files
      xfs: disable preallocations for fsverity Merkle tree writes
      xfs: add writeback and iomap reading of Merkel tree pages
      xfs: add fs-verity support
      xfs: add fs-verity ioctls
      xfs: fix scrub trace with null pointer in quotacheck
      xfs: add fsverity traces
      xfs: enable ro-compat fs-verity flag

Darrick J. Wong (10):
      fsverity: report validation errors back to the filesystem
      fsverity: pass super_block to fsverity_enqueue_verify_work
      ext4: use a per-superblock fsverity workqueue
      f2fs: use a per-superblock fsverity workqueue
      btrfs: use a per-superblock fsverity workqueue
      fsverity: remove system-wide workqueue
      fsverity: expose merkle tree geometry to callers
      xfs: advertise fs-verity being available on filesystem
      xfs: check and repair the verity inode flag state
      xfs: report verity failures through the health system

 Documentation/filesystems/fsverity.rst |   8 +
 MAINTAINERS                            |   1 +
 fs/btrfs/super.c                       |  14 ++
 fs/buffer.c                            |   7 +-
 fs/ext4/readpage.c                     |   4 +-
 fs/ext4/super.c                        |  11 ++
 fs/f2fs/compress.c                     |   3 +-
 fs/f2fs/data.c                         |   2 +-
 fs/f2fs/super.c                        |  11 ++
 fs/ioctl.c                             |  11 ++
 fs/iomap/buffered-io.c                 | 301 ++++++++++++++++++++++++++++--
 fs/iomap/ioend.c                       |  41 +++-
 fs/super.c                             |   3 +
 fs/verity/enable.c                     |   4 +
 fs/verity/fsverity_private.h           |   2 +-
 fs/verity/init.c                       |   2 +-
 fs/verity/open.c                       |  37 ++++
 fs/verity/verify.c                     |  52 +++---
 fs/xfs/Makefile                        |   1 +
 fs/xfs/libxfs/xfs_da_format.h          |  15 +-
 fs/xfs/libxfs/xfs_format.h             |  13 +-
 fs/xfs/libxfs/xfs_fs.h                 |   2 +
 fs/xfs/libxfs/xfs_health.h             |   4 +-
 fs/xfs/libxfs/xfs_inode_buf.c          |   8 +
 fs/xfs/libxfs/xfs_inode_util.c         |   2 +
 fs/xfs/libxfs/xfs_log_format.h         |   1 +
 fs/xfs/libxfs/xfs_sb.c                 |   4 +
 fs/xfs/scrub/attr.c                    |   7 +
 fs/xfs/scrub/common.c                  |  74 ++++++++
 fs/xfs/scrub/common.h                  |   3 +
 fs/xfs/scrub/inode.c                   |   7 +
 fs/xfs/scrub/inode_repair.c            |  36 ++++
 fs/xfs/scrub/trace.h                   |   2 +-
 fs/xfs/xfs_aops.c                      |  21 ++-
 fs/xfs/xfs_bmap_util.c                 |   7 +
 fs/xfs/xfs_file.c                      |  23 ++-
 fs/xfs/xfs_fsverity.c                  | 330 +++++++++++++++++++++++++++++++++
 fs/xfs/xfs_fsverity.h                  |  28 +++
 fs/xfs/xfs_health.c                    |   1 +
 fs/xfs/xfs_inode.h                     |   6 +
 fs/xfs/xfs_ioctl.c                     |  16 ++
 fs/xfs/xfs_iomap.c                     |  22 ++-
 fs/xfs/xfs_iops.c                      |   4 +
 fs/xfs/xfs_mount.h                     |   2 +
 fs/xfs/xfs_super.c                     |  22 +++
 fs/xfs/xfs_trace.h                     |  49 ++++-
 include/linux/fs.h                     |   2 +
 include/linux/fsverity.h               |  49 ++++-
 include/linux/iomap.h                  |  32 ++++
 include/trace/events/fsverity.h        | 162 ++++++++++++++++
 include/uapi/linux/fs.h                |   1 +
 51 files changed, 1399 insertions(+), 71 deletions(-)
---
base-commit: 305d79226a6a797b193ca681e9f26f3bf081397b
change-id: 20250212-fsverity-eb66cef7fe9b

Best regards,
-- 
Andrey Albershteyn <aalbersh@kernel.org>