xfs: flag empty xattr leaf blocks for optimization

Empty xattr leaf blocks at offset zero are a waste of space but
otherwise harmless.  If we encounter one, flag it as an opportunity for
optimization.

If we encounter empty attr leaf blocks anywhere else in the attr fork,
that's corruption.

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

diff --git a/fs/xfs/scrub/attr.c b/fs/xfs/scrub/attr.c
index ba06be86ac7d47e9334c4821884a504bba92e93f..696971204b876f2f03a9cbb98eac11794073579f 100644 (file)
--- a/fs/xfs/scrub/attr.c
+++ b/fs/xfs/scrub/attr.c
@@ -420,6 +420,17 @@ xchk_xattr_block(
        xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
        hdrsize = xfs_attr3_leaf_hdr_size(leaf);
 
+       /*
+        * Empty xattr leaf blocks mapped at block 0 are probably a byproduct
+        * of a race between setxattr and a log shutdown.  Anywhere else in the
+        * attr fork is a corruption.
+        */
+       if (leafhdr.count == 0) {
+               if (blk->blkno == 0)
+                       xchk_da_set_preen(ds, level);
+               else
+                       xchk_da_set_corrupt(ds, level);
+       }
        if (leafhdr.usedbytes > mp->m_attr_geo->blksize)
                xchk_da_set_corrupt(ds, level);
        if (leafhdr.firstused > mp->m_attr_geo->blksize)

diff --git a/fs/xfs/scrub/dabtree.h b/fs/xfs/scrub/dabtree.h
index d654c125feb4d8d7a4d5c4050446ef8fd97a494d..de291e3b77dd8ee117253816d225ddad0f73de7b 100644 (file)
--- a/fs/xfs/scrub/dabtree.h
+++ b/fs/xfs/scrub/dabtree.h
@@ -37,6 +37,8 @@ bool xchk_da_process_error(struct xchk_da_btree *ds, int level, int *error);
 void xchk_da_set_corrupt(struct xchk_da_btree *ds, int level);
 void xchk_da_set_preen(struct xchk_da_btree *ds, int level);
 
+void xchk_da_set_preen(struct xchk_da_btree *ds, int level);
+
 int xchk_da_btree_hash(struct xchk_da_btree *ds, int level, __be32 *hashp);
 int xchk_da_btree(struct xfs_scrub *sc, int whichfork,
                xchk_da_btree_rec_fn scrub_fn, void *private);