[PATCHSET v29.0 02/28] xfs: repair inode mode by scanning dirs

Darrick J. Wong
2023-12-31T19:25:52Z

Hi all,

One missing piece of functionality in the inode record repair code is
figuring out what to do with a file whose mode is so corrupt that we
cannot tell us the type of the file. Originally this was done by
guessing the mode from the ondisk inode contents, but Christoph didn't
like that because it read from data fork block 0, which could be user
controlled data.

Therefore, I've replaced all that with a directory scanner that looks
for any dirents that point to the file with the garbage mode. If so,
the ftype in the dirent will tell us exactly what mode to set on the
file. Since users cannot directly write to the ftype field of a dirent,
this should be safe.

If you're going to start using this code, I strongly recommend pulling
from my git trees, which are linked below.

This has been running on the djcloud for months with no problems. Enjoy!
Comments and questions are, as always, welcome.

--D

kernel git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfs-linux.git/log/?h=repair-inode-mode

xfsprogs git tree:
https://git.kernel.org/cgit/linux/kernel/git/djwong/xfsprogs-dev.git/log/?h=repair-inode-mode
---
fs/xfs/libxfs/xfs_da_format.h | 11 ++
fs/xfs/libxfs/xfs_dir2.c | 6 +
fs/xfs/libxfs/xfs_dir2.h | 10 ++
fs/xfs/scrub/dir.c | 4 -
fs/xfs/scrub/inode_repair.c | 236 ++++++++++++++++++++++++++++++++++++++++-
fs/xfs/scrub/iscan.c | 29 +++++
fs/xfs/scrub/iscan.h | 3 +
fs/xfs/scrub/trace.c | 1
fs/xfs/scrub/trace.h | 49 +++++++++
9 files changed, 341 insertions(+), 8 deletions(-)