xfs: Add helper function xfs_attr_leaf_addname

This patch adds a helper function xfs_attr_leaf_addname.  While this
does help to break down xfs_attr_set_iter, it does also hoist out some
of the state management.  This patch has been moved to the end of the
clean up series for further discussion.
Suggested-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_attr.c

@@ -286,44 +286,16 @@ xfs_attr_sf_addname(
 	return -EAGAIN;
 }
 
-/*
- * Set the attribute specified in @args.
- * This routine is meant to function as a delayed operation, and may return
- * -EAGAIN when the transaction needs to be rolled.  Calling functions will need
- * to handle this, and recall the function until a successful error code is
- * returned.
- */
-int
-xfs_attr_set_iter(
+STATIC int
+xfs_attr_leaf_addname(
 	struct xfs_attr_item	*attr)
 {
 	struct xfs_da_args	*args = attr->xattri_da_args;
 	struct xfs_inode	*dp = args->dp;
-	struct xfs_buf			*bp = NULL;
-	int				forkoff, error = 0;
-	struct xfs_mount		*mp = args->dp->i_mount;
-
-	/* State machine switch */
-	switch (attr->xattri_dela_state) {
-	case XFS_DAS_UNINIT:
-		/*
-		 * If the fork is shortform, attempt to add the attr. If there
-		 * is no space, this converts to leaf format and returns
-		 * -EAGAIN with the leaf buffer held across the roll. The caller
-		 * will deal with a transaction roll error, but otherwise
-		 * release the hold once we return with a clean transaction.
-		 */
-		if (xfs_attr_is_shortform(dp))
-			return xfs_attr_sf_addname(attr);
-		if (attr->xattri_leaf_bp != NULL) {
-			xfs_trans_bhold_release(args->trans,
-						attr->xattri_leaf_bp);
-			attr->xattri_leaf_bp = NULL;
-		}
+	int			error;
 
 	if (xfs_attr_is_leaf(dp)) {
-			error = xfs_attr_leaf_try_add(args,
-						      attr->xattri_leaf_bp);
+		error = xfs_attr_leaf_try_add(args, attr->xattri_leaf_bp);
 		if (error == -ENOSPC) {
 			error = xfs_attr3_leaf_to_node(args);
 			if (error)
@@ -331,24 +303,23 @@ xfs_attr_set_iter(
 
 			/*
 			 * Finish any deferred work items and roll the
-				 * transaction once more.  The goal here is to
-				 * call node_addname with the inode and
-				 * transaction in the same state (inode locked
-				 * and joined, transaction clean) no matter how
-				 * we got to this step.
+			 * transaction once more.  The goal here is to call
+			 * node_addname with the inode and transaction in the
+			 * same state (inode locked and joined, transaction
+			 * clean) no matter how we got to this step.
 			 *
-				 * At this point, we are still in
-				 * XFS_DAS_UNINIT, but when we come back, we'll
-				 * be a node, so we'll fall down into the node
-				 * handling code below
+			 * At this point, we are still in XFS_DAS_UNINIT, but
+			 * when we come back, we'll be a node, so we'll fall
+			 * down into the node handling code below
 			 */
 			trace_xfs_attr_set_iter_return(
 				attr->xattri_dela_state, args->dp);
 			return -EAGAIN;
-			} else if (error) {
-				return error;
 		}
 
+		if (error)
+			return error;
+
 		attr->xattri_dela_state = XFS_DAS_FOUND_LBLK;
 	} else {
 		error = xfs_attr_node_addname_find_attr(attr);
@@ -360,8 +331,8 @@ xfs_attr_set_iter(
 			return error;
 
 		/*
-			 * If addname was successful, and we dont need to alloc
-			 * or remove anymore blks, we're done.
+		 * If addname was successful, and we dont need to alloc or
+		 * remove anymore blks, we're done.
 		 */
 		if (!args->rmtblkno &&
 		    !(args->op_flags & XFS_DA_OP_RENAME))
@@ -369,9 +340,48 @@ xfs_attr_set_iter(
 
 		attr->xattri_dela_state = XFS_DAS_FOUND_NBLK;
 	}
-		trace_xfs_attr_set_iter_return(attr->xattri_dela_state,
-					       args->dp);
+
+	trace_xfs_attr_leaf_addname_return(attr->xattri_dela_state, args->dp);
 	return -EAGAIN;
+}
+
+/*
+ * Set the attribute specified in @args.
+ * This routine is meant to function as a delayed operation, and may return
+ * -EAGAIN when the transaction needs to be rolled.  Calling functions will need
+ * to handle this, and recall the function until a successful error code is
+ * returned.
+ */
+int
+xfs_attr_set_iter(
+	struct xfs_attr_item		*attr)
+{
+	struct xfs_da_args              *args = attr->xattri_da_args;
+	struct xfs_inode		*dp = args->dp;
+	struct xfs_buf			*bp = NULL;
+	int				forkoff, error = 0;
+	struct xfs_mount		*mp = args->dp->i_mount;
+
+	/* State machine switch */
+	switch (attr->xattri_dela_state) {
+	case XFS_DAS_UNINIT:
+		/*
+		 * If the fork is shortform, attempt to add the attr. If there
+		 * is no space, this converts to leaf format and returns
+		 * -EAGAIN with the leaf buffer held across the roll. The caller
+		 * will deal with a transaction roll error, but otherwise
+		 * release the hold once we return with a clean transaction.
+		 */
+		if (xfs_attr_is_shortform(dp))
+			return xfs_attr_sf_addname(attr);
+		if (attr->xattri_leaf_bp != NULL) {
+			xfs_trans_bhold_release(args->trans,
+						attr->xattri_leaf_bp);
+			attr->xattri_leaf_bp = NULL;
+		}
+
+		return xfs_attr_leaf_addname(attr);
+
 	case XFS_DAS_FOUND_LBLK:
 		/*
 		 * If there was an out-of-line value, allocate the blocks we

fs/xfs/xfs_trace.h

@@ -4150,6 +4150,7 @@ DEFINE_EVENT(xfs_das_state_class, name, \
 	TP_ARGS(das, ip))
 DEFINE_DAS_STATE_EVENT(xfs_attr_sf_addname_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_set_iter_return);
+DEFINE_DAS_STATE_EVENT(xfs_attr_leaf_addname_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_node_addname_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_remove_iter_return);
 DEFINE_DAS_STATE_EVENT(xfs_attr_rmtval_remove_return);