fs-verity support for XFS

Hi all,

Here's v5 of my patchset of adding fs-verity support to XFS.

This implementation uses extended attributes to store fs-verity
metadata. The Merkle tree blocks are stored in the remote extended
attributes. The names are offsets into the tree.

A few key points of this patchset:
- fs-verity can work with Merkle tree blocks based caching (xfs) and
  PAGE caching (ext4, f2fs, btrfs)
- iomap does fs-verity verification
- In XFS, fs-verity metadata is stored in extended attributes
- per-sb workqueue for verification processing
- Inodes with fs-verity have new on-disk diflag
- xfs_attr_get() can return a buffer with an extended attribute
- xfs_buf can allocate double space for Merkle tree blocks. Part of
  the space is used to store  the extended attribute data without
  leaf headers
- xfs_buf tracks verified status of merkle tree blocks

The patchset consists of five parts:
- [1]: fs-verity spinlock removal pending in fsverity/for-next
- [2..4]: Parent pointers adding binary xattr names
- [5]: Expose FS_XFLAG_VERITY for fs-verity files
- [6..9]: Changes to fs-verity core
- [10]: Integrate fs-verity to iomap
- [11-24]: Add fs-verity support to XFS

Testing:
The patchset is tested with xfstests -g verity on xfs_1k, xfs_4k,
xfs_1k_quota, xfs_4k_quota, ext4_4k, and ext4_4k_quota. With
KMEMLEAK and KASAN enabled. More testing on the way.

Changes from V4:
- Mainly fs-verity changes; removed unnecessary functions
- Replace XFS workqueue with per-sb workqueue created in
  fsverity_set_ops()
- Drop patch with readahead calculation in bytes
Changes from V3:
- redone changes to fs-verity core as previous version had an issue
  on ext4
- add blocks invalidation interface to fs-verity
- move memory ordering primitives out of block status check to fs
  read block function
- add fs-verity verification to iomap instead of general post read
  processing
Changes from V2:
- FS_XFLAG_VERITY extended attribute flag
- Change fs-verity to use Merkle tree blocks instead of expecting
  PAGE references from filesystem
- Change approach in iomap to filesystem provided bio_set and
  submit_io instead of just callouts to filesystem
- Add possibility for xfs_buf allocate more space for fs-verity
  extended attributes
- Make xfs_attr module to copy fs-verity blocks inside the xfs_buf,
  so XFS can get data without leaf headers
- Add Merkle tree removal for error path
- Makae scrub aware of new dinode flag
Changes from V1:
- Added parent pointer patches for easier testing
- Many issues and refactoring points fixed from the V1 review
- Adjusted for recent changes in fs-verity core (folios, non-4k)
- Dropped disabling of large folios
- Completely new fsverity patches (fix, callout, log_blocksize)
- Change approach to verification in iomap to the same one as in
  write path. Callouts to fs instead of direct fs-verity use.
- New XFS workqueue for post read folio verification
- xfs_attr_get() can return underlying xfs_buf
- xfs_bufs are marked with XBF_VERITY_CHECKED to track verified
  blocks

kernel:
[1]: https://github.com/alberand/linux/tree/fsverity-v5

xfsprogs:
[2]: https://github.com/alberand/xfsprogs/tree/fsverity-v5

xfstests:
[3]: https://github.com/alberand/xfstests/tree/fsverity-v5

v1:
[4]: https://lore.kernel.org/linux-xfs/20221213172935.680971-1...

v2:
[5]: https://lore.kernel.org/linux-xfs/20230404145319.2057051-...

v3:
[6]: https://lore.kernel.org/all/20231006184922.252188-1-aalbe...

v4:
[7]: https://lore.kernel.org/linux-xfs/20240212165821.1901300-...

fs-verity:
[7]: https://www.kernel.org/doc/html/latest/filesystems/fsveri...

Thanks,
Andrey

Allison Henderson (3):
  xfs: add parent pointer support to attribute code
  xfs: define parent pointer ondisk extended attribute format
  xfs: add parent pointer validator functions

Andrey Albershteyn (21):
  fsverity: remove hash page spin lock
  fs: add FS_XFLAG_VERITY for verity files
  fsverity: pass tree_blocksize to end_enable_verity()
  fsverity: support block-based Merkle tree caching
  fsverity: add per-sb workqueue for post read processing
  fsverity: add tracepoints
  iomap: integrate fs-verity verification into iomap's read path
  xfs: add XBF_VERITY_SEEN xfs_buf flag
  xfs: add XFS_DA_OP_BUFFER to make xfs_attr_get() return buffer
  xfs: add attribute type for fs-verity
  xfs: make xfs_buf_get() to take XBF_* flags
  xfs: add XBF_DOUBLE_ALLOC to increase size of the buffer
  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 sealsed inode
  xfs: disable direct read path for fs-verity files
  xfs: add fs-verity support
  xfs: make scrub aware of verity dinode flag
  xfs: add fs-verity ioctls
  xfs: enable ro-compat fs-verity flag

 Documentation/filesystems/fsverity.rst |   8 +
 MAINTAINERS                            |   1 +
 fs/btrfs/verity.c                      |   4 +-
 fs/ext4/verity.c                       |   3 +-
 fs/f2fs/verity.c                       |   3 +-
 fs/ioctl.c                             |  11 +
 fs/iomap/buffered-io.c                 |  92 ++++++-
 fs/super.c                             |   7 +
 fs/verity/enable.c                     |   9 +-
 fs/verity/fsverity_private.h           |  11 +-
 fs/verity/init.c                       |   1 +
 fs/verity/open.c                       |   9 +-
 fs/verity/read_metadata.c              |  64 +++--
 fs/verity/signature.c                  |   2 +
 fs/verity/verify.c                     | 180 +++++++++----
 fs/xfs/Makefile                        |   2 +
 fs/xfs/libxfs/xfs_attr.c               |  31 ++-
 fs/xfs/libxfs/xfs_attr.h               |   3 +-
 fs/xfs/libxfs/xfs_attr_leaf.c          |  24 +-
 fs/xfs/libxfs/xfs_attr_remote.c        |  39 ++-
 fs/xfs/libxfs/xfs_btree_mem.c          |   2 +-
 fs/xfs/libxfs/xfs_da_btree.h           |   5 +-
 fs/xfs/libxfs/xfs_da_format.h          |  68 ++++-
 fs/xfs/libxfs/xfs_format.h             |  14 +-
 fs/xfs/libxfs/xfs_log_format.h         |   2 +
 fs/xfs/libxfs/xfs_ondisk.h             |   4 +
 fs/xfs/libxfs/xfs_parent.c             | 113 ++++++++
 fs/xfs/libxfs/xfs_parent.h             |  19 ++
 fs/xfs/libxfs/xfs_sb.c                 |   4 +-
 fs/xfs/scrub/attr.c                    |   4 +-
 fs/xfs/xfs_attr_item.c                 |   6 +-
 fs/xfs/xfs_attr_list.c                 |  14 +-
 fs/xfs/xfs_buf.c                       |   6 +-
 fs/xfs/xfs_buf.h                       |  23 +-
 fs/xfs/xfs_file.c                      |  23 +-
 fs/xfs/xfs_inode.c                     |   2 +
 fs/xfs/xfs_inode.h                     |   3 +-
 fs/xfs/xfs_ioctl.c                     |  22 ++
 fs/xfs/xfs_iops.c                      |   4 +
 fs/xfs/xfs_mount.h                     |   2 +
 fs/xfs/xfs_super.c                     |  12 +
 fs/xfs/xfs_trace.h                     |   4 +-
 fs/xfs/xfs_verity.c                    | 355 +++++++++++++++++++++++++
 fs/xfs/xfs_verity.h                    |  33 +++
 fs/xfs/xfs_xattr.c                     |  10 +
 include/linux/fs.h                     |   2 +
 include/linux/fsverity.h               |  91 ++++++-
 include/trace/events/fsverity.h        | 181 +++++++++++++
 include/uapi/linux/fs.h                |   1 +
 49 files changed, 1395 insertions(+), 138 deletions(-)
 create mode 100644 fs/xfs/libxfs/xfs_parent.c
 create mode 100644 fs/xfs/libxfs/xfs_parent.h
 create mode 100644 fs/xfs/xfs_verity.c
 create mode 100644 fs/xfs/xfs_verity.h
 create mode 100644 include/trace/events/fsverity.h

-- 
2.42.0