Once in a long while, xfs/566 and xfs/801 report directory corruption in
one of the metadata subdirectories while it's forcibly rebuilding all
filesystem metadata. I observed the following sequence of events:
1. Initiate a repair of the parent pointers for the /quota/user file.
This is the secret file containing user quota data.
2. The pptr repair thread creates a temporary file and begins staging
parent pointers in the ondisk metadata in preparation for an
exchange-range to commit the new pptr data.
3. At the same time, initiate a repair of the /quota directory itself.
4. The dir repair thread finds the temporary file from (2), scans it for
parent pointers, and stages a dirent in its own temporary dir in
preparation to commit the fixed directory.
5. The parent pointer repair completes and frees the temporary file.
6. The dir repair commits the new directory and scans it again. It
finds the dirent that points to the old temporary file in (2) and
marks the directory corrupt.
Oops! Repair code must never scan the temporary files that other repair
functions create to stage new metadata. They're not supposed to do
that, but the predicate function xrep_is_tempfile is incorrect because
it assumes that any XFS_DIFLAG2_METADATA file cannot ever be a temporary
file, but xrep_tempfile_adjust_directory_tree creates exactly that.
Fix this by setting the IRECOVERY flag on temporary metadata directory
inodes and using that to correct the predicate. Repair code is supposed
to erase all the data in temporary files before releasing them, so it's
ok if a thread scans the temporary file after we drop IRECOVERY.
Cc: <stable@vger.kernel.org> # v6.13-rc1
Fixes: bb6cdd5529ff67 ("xfs: hide metadata inodes from everyone because they are special")
Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
dc5a052739