The pad field in xfs_dir3_data_hdr exists for 64-bit alignment and
should always be zero. Old kernels zeroed only the xfs_dir3_blk_hdr
portion of the header during initialization and initialized the
remaining header contents separately.
This series takes a broader approach as suggested by Dave Chinner:
zero the entire header region unconditionally, self-heal stale non-zero
padding during writes, and report remaining non-zero padding in scrub.
Patch 1 zeroes the entire directory data block header region in
xfs_dir3_data_init instead of just the xfs_dir3_blk_hdr.
Patch 2 zeroes the pad field in xfs_dir3_data_write_verify so that
existing directories self-heal when modified.
Patch 3 checks the pad field in scrub and adds xchk_fblock_set_preen.
Changes in v3:
- Zero the entire header region (geo->data_entry_offset bytes)
unconditionally instead of changing the memset type to
xfs_dir3_data_hdr.
- Remove the now-unnecessary bestfree manual zeroing loop.
- Zero pad in xfs_dir3_data_write_verify for runtime self-healing
of old metadata.
- Drop unnecessary cpu_to_be32() on comparison to zero.
- Split into a 3-patch series for easier review.
- Link to v2: https://lore.kernel.org/all/20260408172749.99216-2-ytohnuki@amazon.com/#t
Changes in v2:
- Fix xfs_dir3_data_init to zero the full xfs_dir3_data_hdr instead of
just xfs_dir3_blk_hdr so that the pad field is covered by the memset.
- Use xchk_fblock_set_preen instead of xchk_fblock_set_corrupt since
old kernels may have written non-zero padding without issues.
- Add xchk_fblock_set_preen helper function.
- Link to v1: https://lore.kernel.org/all/20260404125032.37693-2-ytohnuki@amazon.com/#t
Yuto Ohnuki (3):
xfs: zero entire directory data block header region at init
xfs: zero directory data block padding on write verification
xfs: check directory data block header padding in scrub
fs/xfs/libxfs/xfs_dir2_data.c | 18 +++++++++++-------
fs/xfs/scrub/common.c | 11 +++++++++++
fs/xfs/scrub/common.h | 2 ++
fs/xfs/scrub/dir.c | 7 ++++++-
4 files changed, 30 insertions(+), 8 deletions(-)
--
2.50.1
Amazon Web Services EMEA SARL, 38 avenue John F. Kennedy, L-1855 Luxembourg, R.C.S. Luxembourg B186284
Amazon Web Services EMEA SARL, Irish Branch, One Burlington Plaza, Burlington Road, Dublin 4, Ireland, branch registration number 908705