xfs: Refactor xfs_attr_rmtval_remove

Refactor xfs_attr_rmtval_remove to add helper function
__xfs_attr_rmtval_remove. We will use this later when we introduce
delayed attributes.  This function will eventually replace
xfs_attr_rmtval_remove
Signed-off-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Dave Chinner <dchinner@redhat.com>

fs/xfs/libxfs/xfs_attr_remote.c

@@ -678,10 +678,8 @@ int
 xfs_attr_rmtval_remove(
 	struct xfs_da_args      *args)
 {
-	xfs_dablk_t		lblkno;
-	int			blkcnt;
-	int			error = 0;
-	int			done = 0;
+	int			error;
+	int			retval;
 
 	trace_xfs_attr_rmtval_remove(args);
 
@@ -691,16 +689,10 @@ xfs_attr_rmtval_remove(
 	/*
 	 * Keep de-allocating extents until the remote-value region is gone.
 	 */
-	lblkno = args->rmtblkno;
-	blkcnt = args->rmtblkcnt;
-	while (!done) {
-		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
-				    XFS_BMAPI_ATTRFORK, 1, &done);
-		if (error)
-			return error;
-		error = xfs_defer_finish(&args->trans);
-		if (error)
-			return error;
+	do {
+		retval = __xfs_attr_rmtval_remove(args);
+		if (retval && retval != -EAGAIN)
+			return retval;
 
 		/*
 		 * Close out trans and start the next one in the chain.
@@ -708,6 +700,36 @@ xfs_attr_rmtval_remove(
 		error = xfs_trans_roll_inode(&args->trans, args->dp);
 		if (error)
 			return error;
-	}
+	} while (retval == -EAGAIN);
+
 	return 0;
 }
+
+/*
+ * Remove the value associated with an attribute by deleting the out-of-line
+ * buffer that it is stored on. Returns EAGAIN for the caller to refresh the
+ * transaction and re-call the function
+ */
+int
+__xfs_attr_rmtval_remove(
+	struct xfs_da_args	*args)
+{
+	int			error, done;
+
+	/*
+	 * Unmap value blocks for this attr.
+	 */
+	error = xfs_bunmapi(args->trans, args->dp, args->rmtblkno,
+			    args->rmtblkcnt, XFS_BMAPI_ATTRFORK, 1, &done);
+	if (error)
+		return error;
+
+	error = xfs_defer_finish(&args->trans);
+	if (error)
+		return error;
+
+	if (!done)
+		return -EAGAIN;
+
+	return error;
+}

fs/xfs/libxfs/xfs_attr_remote.h

@@ -14,4 +14,5 @@ int xfs_attr_rmtval_remove(struct xfs_da_args *args);
 int xfs_attr_rmtval_stale(struct xfs_inode *ip, struct xfs_bmbt_irec *map,
 		xfs_buf_flags_t incore_flags);
 int xfs_attr_rmtval_invalidate(struct xfs_da_args *args);
+int __xfs_attr_rmtval_remove(struct xfs_da_args *args);
 #endif /* __XFS_ATTR_REMOTE_H__ */