[PATCH v8 00/22] fs-verity support for XFS with post EOF merkle tree

Andrey Albershteyn
2026-04-20T11:47:35Z

Hi all,

This patch series adds fs-verity support for XFS. This version stores
merkle tree beyond end of the file, the same way as ext4 does it. The
difference is that verity descriptor is stored at the next aligned 64k
block after the merkle tree last block. This is done due to sparse
merkle tree which doesn't store hashes of zero data blocks.

The patchset starts with a few fs-verity preparation patches. Then, a
few patches to allow iomap to work in post EOF region. The XFS fs-verity
implementation follows.

The tree is read by iomap into page cache at offset of next largest
folio past end of file. The same offset is used for on-disk.

This patchsets also synthesizes merkle tree block full of hashes of
zeroed data blocks. This merkle blocks are not stored on disk, they are
holes in the tree.

Testing. The -g verity is passing for 1k, 8k and 4k with/without quota
on 4k and 64k page size systems. Tested -g quick for enabled/disabled
fsverity. Also, overlay/080 overlay/089 with XFS as base.

This series based on v7.0 with Christoph's read ioends patchset [1].

kernel:
https://git.kernel.org/pub/scm/linux/kernel/git/aalbersh/xfs-linux.git/log/?h=b4/fsverity

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: linux-unionfs@vger.kernel.org

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

1: https://lore.kernel.org/linux-xfs/20260223132021.292832-1-hch@lst.de/

---
Changes in v8:
- Return fsverity_ensure_verity_info() errors from
ovl_ensure_verity_loaded()
Changes in v7:
- Move kerneldoc to fsverity_ensure_verity_info() definition
- Drop patch adding XFS traces
- Fix overly long line in the comment
- Make order of fserror and fsverity_error consistent
- Add overlay patch converting to fsverity_ensure_verity_info()
Changes in v6:
- Removed stub for fsverity_ensure_verity_info() as it's optimized out
- Rename fsverity_folio_zero_hash() to fsverify_fill_zerohash()
- Merge patches 8 to 10 into one
- Merge patch gerating zero_hash and fsverity_fill_zerohash() into one
- Add kerneldoc to fsverity_ensure_verity_info()
- Add comments to iomap_block_needs_zeroing()
Changes in v5:
- Add fserror_report_data_lost() for data blocks in page spanning EOF
- Issue fsverity metadata readahead in data readahead
- iomap_fsverity_write() return type fix
- Use of S_ISREG(mode)
- Make 65536 #define instead of open-coded
- Use transaction per unwritten extent removal
- Fetch fsverity_info for all fsverity metadata
- Revert fsverity_folio_zero_hash() stub as used in iomap
- Extend cancel_unwritten to whole file range to remove cow leftovers
- Drop delayed allocation on the COW fork on fsverity completion
Changes in v4:
- Use fserror interface in fsverity instead of fs callback
- Hoist pagecache_read from f2fs/ext4 to fsverity
- Refactor iomap code
- Fetch fsverity_info only for file data and merkle tree holes
- Do not disable preallocation, remove unwritten extents instead
- Offload fsverity hash I/O to fsverity workqueue in read path
- Store merkle tree at round_up(i_size, 64k)
- Add a spacing between merkle tree and fsverity descriptor as next 64k
aligned block
- Squash helpers into first user commits
- Squash on-disk format changes into single commit
- Drop different offset for pagecache/on-disk
- Don't zero out pages in higher order folios in write path
- Link to v3: https://lore.kernel.org/fsverity/20260217231937.1183679-1-aalbersh@kernel.org/T/#t
Changes in v3:
- Different on-disk and pagecache offset
- Use read path ioends
- Switch to hashtable fsverity info
- Synthesize merkle tree blocks full of zeroes
- Other minor refactors
- Link to v2: https://lore.kernel.org/fsverity/20260114164210.GO15583@frogsfrogsfrogs/T/#t
Changes in v2:
- Move to VFS interface for merkle tree block reading
- Drop patchset for per filesystem workqueues
- Change how offsets of the descriptor and tree metadata is calculated
- Store fs-verity descriptor in data fork side by side with merkle tree
- Simplify iomap changes, remove interface for post eof read/write
- Get rid of extended attribute implementation
- Link to v1: https://lore.kernel.org/r/20250728-fsverity-v1-0-9e5443af0e34@kernel.org

Andrey Albershteyn (20):
fsverity: report validation errors through fserror to fsnotify
fsverity: expose ensure_fsverity_info()
ovl: use core fsverity ensure info interface
fsverity: generate and store zero-block hash
fsverity: pass digest size and hash of the all-zeroes block to ->write
fsverity: hoist pagecache_read from f2fs/ext4 to fsverity
iomap: introduce IOMAP_F_FSVERITY and teach writeback to handle
fsverity
iomap: teach iomap to read files with fsverity
iomap: introduce iomap_fsverity_write() for writing fsverity metadata
xfs: introduce fsverity on-disk changes
xfs: initialize fs-verity on file open
xfs: don't allow to enable DAX on fs-verity sealed inode
xfs: disable direct read path for fs-verity files
xfs: handle fsverity I/O in write/read path
xfs: use read ioend for fsverity data verification
xfs: add fs-verity support
xfs: remove unwritten extents after preallocations in fsverity
metadata
xfs: add fs-verity ioctls
xfs: introduce health state for corrupted fsverity metadata
xfs: enable ro-compat fs-verity flag

Darrick J. Wong (2):
xfs: advertise fs-verity being available on filesystem
xfs: check and repair the verity inode flag state

fs/btrfs/verity.c | 6 +-
fs/ext4/verity.c | 36 +--
fs/f2fs/verity.c | 34 +--
fs/iomap/buffered-io.c | 109 +++++++-
fs/iomap/trace.h | 3 +-
fs/overlayfs/util.c | 14 +-
fs/verity/enable.c | 4 +-
fs/verity/fsverity_private.h | 3 +
fs/verity/measure.c | 4 +-
fs/verity/open.c | 25 +-
fs/verity/pagecache.c | 55 ++++
fs/verity/verify.c | 4 +
fs/xfs/Makefile | 1 +
fs/xfs/libxfs/xfs_bmap.c | 7 +
fs/xfs/libxfs/xfs_format.h | 35 ++-
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_sb.c | 4 +
fs/xfs/scrub/attr.c | 7 +
fs/xfs/scrub/common.c | 53 ++++
fs/xfs/scrub/common.h | 2 +
fs/xfs/scrub/inode.c | 7 +
fs/xfs/scrub/inode_repair.c | 36 +++
fs/xfs/xfs_aops.c | 62 ++++-
fs/xfs/xfs_bmap_util.c | 8 +
fs/xfs/xfs_file.c | 19 +-
fs/xfs/xfs_fsverity.c | 455 +++++++++++++++++++++++++++++++++
fs/xfs/xfs_fsverity.h | 28 ++
fs/xfs/xfs_health.c | 1 +
fs/xfs/xfs_inode.h | 6 +
fs/xfs/xfs_ioctl.c | 14 +
fs/xfs/xfs_iomap.c | 15 +-
fs/xfs/xfs_iops.c | 4 +
fs/xfs/xfs_message.c | 4 +
fs/xfs/xfs_message.h | 1 +
fs/xfs/xfs_mount.h | 4 +
fs/xfs/xfs_super.c | 7 +
include/linux/fsverity.h | 18 +-
include/linux/iomap.h | 13 +
41 files changed, 1017 insertions(+), 107 deletions(-)
create mode 100644 fs/xfs/xfs_fsverity.c
create mode 100644 fs/xfs/xfs_fsverity.h

--
2.51.2