xfs: ignore leaf attr ichdr.count in verifier during log replay

commit 2e1d23370e75d7d89350d41b4ab58c7f6a0e26b2 upstream.

When we create a new attribute, we first create a shortform
attribute, and try to fit the new attribute into it.
If that fails, we copy the (empty) attribute into a leaf attribute,
and do the copy again.  Thus there can be a transient state where
we have an empty leaf attribute.

If we encounter this during log replay, the verifier will fail.
So add a test to ignore this part of the leaf attr verification
during log replay.

Thanks as usual to dchinner for spotting the problem.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 8ea91f363093..2852521fc8ec 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -253,6 +253,7 @@ xfs_attr3_leaf_verify(
 {
         struct xfs_mount        *mp = bp->b_target->bt_mount;
         struct xfs_attr_leafblock *leaf = bp->b_addr;
+        struct xfs_perag *pag = bp->b_pag;
         struct xfs_attr3_icleaf_hdr ichdr;
 
         xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);
@@ -273,7 +274,12 @@ xfs_attr3_leaf_verify(
                 if (ichdr.magic != XFS_ATTR_LEAF_MAGIC)
                         return false;
         }
-        if (ichdr.count == 0)
+        /*
+         * In recovery there is a transient state where count == 0 is valid
+         * because we may have transitioned an empty shortform attr to a leaf
+         * if the attr didn't fit in shortform.
+         */
+        if (pag && pag->pagf_init && ichdr.count == 0)
                 return false;
 
         /* XXX: need to range check rest of attr header values */