xfs: don't hold xattr leaf buffers across transaction rolls

Now that we've established (again!) that empty xattr leaf buffers are
ok, we no longer need to bhold them to transactions when we're creating
new leaf blocks.  Get rid of the entire mechanism, which should simplify
the xattr code quite a bit.

The original justification for using bhold here was to prevent the AIL
from trying to write the empty leaf block into the fs during the brief
time that we release the buffer lock.  The reason for /that/ was to
prevent recovery from tripping over the empty ondisk block.

Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 9 insertions, 29 deletions

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 1824f61621a2..224649a76cbb 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -50,7 +50,7 @@ STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
 STATIC int xfs_attr_leaf_hasname(struct xfs_da_args *args, struct xfs_buf **bp);
-STATIC int xfs_attr_leaf_try_add(struct xfs_da_args *args, struct xfs_buf *bp);
+STATIC int xfs_attr_leaf_try_add(struct xfs_da_args *args);
 
 /*
  * Internal routines when attribute list is more than one block.
@@ -393,16 +393,10 @@ xfs_attr_sf_addname(
 	 * It won't fit in the shortform, transform to a leaf block.  GROT:
 	 * another possible req'mt for a double-split btree op.
 	 */
-	error = xfs_attr_shortform_to_leaf(args, &attr->xattri_leaf_bp);
+	error = xfs_attr_shortform_to_leaf(args);
 	if (error)
 		return error;
 
-	/*
-	 * Prevent the leaf buffer from being unlocked so that a concurrent AIL
-	 * push cannot grab the half-baked leaf buffer and run into problems
-	 * with the write verifier.
-	 */
-	xfs_trans_bhold(args->trans, attr->xattri_leaf_bp);
 	attr->xattri_dela_state = XFS_DAS_LEAF_ADD;
 out:
 	trace_xfs_attr_sf_addname_return(attr->xattri_dela_state, args->dp);
@@ -447,11 +441,9 @@ xfs_attr_leaf_addname(
 
 	/*
 	 * Use the leaf buffer we may already hold locked as a result of
-	 * a sf-to-leaf conversion. The held buffer is no longer valid
-	 * after this call, regardless of the result.
+	 * a sf-to-leaf conversion.
 	 */
-	error = xfs_attr_leaf_try_add(args, attr->xattri_leaf_bp);
-	attr->xattri_leaf_bp = NULL;
+	error = xfs_attr_leaf_try_add(args);
 
 	if (error == -ENOSPC) {
 		error = xfs_attr3_leaf_to_node(args);
@@ -497,8 +489,6 @@ xfs_attr_node_addname(
 	struct xfs_da_args	*args = attr->xattri_da_args;
 	int			error;
 
-	ASSERT(!attr->xattri_leaf_bp);
-
 	error = xfs_attr_node_addname_find_attr(attr);
 	if (error)
 		return error;
@@ -1215,24 +1205,14 @@ xfs_attr_restore_rmt_blk(
  */
 STATIC int
 xfs_attr_leaf_try_add(
-	struct xfs_da_args	*args,
-	struct xfs_buf		*bp)
+	struct xfs_da_args	*args)
 {
+	struct xfs_buf		*bp;
 	int			error;
 
-	/*
-	 * If the caller provided a buffer to us, it is locked and held in
-	 * the transaction because it just did a shortform to leaf conversion.
-	 * Hence we don't need to read it again. Otherwise read in the leaf
-	 * buffer.
-	 */
-	if (bp) {
-		xfs_trans_bhold_release(args->trans, bp);
-	} else {
-		error = xfs_attr3_leaf_read(args->trans, args->dp, 0, &bp);
-		if (error)
-			return error;
-	}
+	error = xfs_attr3_leaf_read(args->trans, args->dp, 0, &bp);
+	if (error)
+		return error;
 
 	/*
 	 * Look up the xattr name to set the insertion point for the new xattr.