xfs: hold xfs_buf locked between shortform->leaf conversion and the addition of an attribute
The new attribute leaf buffer is not held locked across the transaction
roll between the shortform->leaf modification and the addition of the
new entry. As a result, the attribute buffer modification being made is
not atomic from an operational perspective. Hence the AIL push can grab
it in the transient state of "just created" after the initial
transaction is rolled, because the buffer has been released. This leads
to xfs_attr3_leaf_verify() asserting that hdr.count is zero, treating
this as in-memory corruption, and shutting down the filesystem.
Darrick ported the original patch to 4.15 and reworked it use the
xfs_defer_bjoin helper and hold/join the buffer correctly across the
second transaction roll.
Signed-off-by: Alex Lyakas <alex@zadarastorage.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h b/fs/xfs/libxfs/xfs_attr_leaf.h
index f7dda0c..894124e 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.h
+++ b/fs/xfs/libxfs/xfs_attr_leaf.h
@@ -48,7 +48,8 @@ void xfs_attr_shortform_create(struct xfs_da_args *args);
void xfs_attr_shortform_add(struct xfs_da_args *args, int forkoff);
int xfs_attr_shortform_lookup(struct xfs_da_args *args);
int xfs_attr_shortform_getvalue(struct xfs_da_args *args);
-int xfs_attr_shortform_to_leaf(struct xfs_da_args *args);
+int xfs_attr_shortform_to_leaf(struct xfs_da_args *args,
+ struct xfs_buf **leaf_bp);
int xfs_attr_shortform_remove(struct xfs_da_args *args);
int xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
int xfs_attr_shortform_bytesfit(struct xfs_inode *dp, int bytes);