xfs: set inode sick state flags when we zap either ondisk fork

In a few patches, we'll add some online repair code that tries to
massage the ondisk inode record just enough to get it to pass the inode
verifiers so that we can continue with more file repairs.  Part of that
massaging can include zapping the ondisk forks to clear errors.  After
that point, the bmap fork repair functions will rebuild the zapped
forks.

Christoph asked for stronger protections against online repair zapping a
fork to get the inode to load vs. other threads trying to access the
partially repaired file.  Do this by adding a special "[DA]FORK_ZAPPED"
inode health flag whenever repair zaps a fork, and sprinkling checks for
that flag into the various file operations for things that don't like
handling an unexpected zero-extents fork.

In practice xfs_scrub will scrub and fix the forks almost immediately
after zapping them, so the window is very small.  However, if a crash or
unmount should occur, we can still detect these zapped inode forks by
looking for a zero-extents fork when data was expected.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/xfs/scrub/health.h b/fs/xfs/scrub/health.h
index 66a273f8585b..a731b2467399 100644
--- a/fs/xfs/scrub/health.h
+++ b/fs/xfs/scrub/health.h
@@ -10,5 +10,7 @@ unsigned int xchk_health_mask_for_scrub_type(__u32 scrub_type);
 void xchk_update_health(struct xfs_scrub *sc);
 bool xchk_ag_btree_healthy_enough(struct xfs_scrub *sc, struct xfs_perag *pag,
 		xfs_btnum_t btnum);
+void xchk_mark_healthy_if_clean(struct xfs_scrub *sc, unsigned int mask);
+bool xchk_file_looks_zapped(struct xfs_scrub *sc, unsigned int mask);
 
 #endif /* __XFS_SCRUB_HEALTH_H__ */