xfs: Factor out xfs_attr_rmtval_invalidate

Because new delayed attribute routines cannot roll transactions, we
carve off the parts of xfs_attr_rmtval_remove that we can use.  This
will help to reduce repetitive code later when we introduce delayed
attributes.
Signed-off-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.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

@@ -634,15 +634,12 @@ xfs_attr_rmtval_set(
  * out-of-line buffer that it is stored on.
  */
 int
-xfs_attr_rmtval_remove(
+xfs_attr_rmtval_invalidate(
 	struct xfs_da_args	*args)
 {
 	xfs_dablk_t		lblkno;
 	int			blkcnt;
 	int			error;
-	int			done;
-
-	trace_xfs_attr_rmtval_remove(args);
 
 	/*
 	 * Roll through the "value", invalidating the attribute value's blocks.
@@ -670,13 +667,32 @@ xfs_attr_rmtval_remove(
 		lblkno += map.br_blockcount;
 		blkcnt -= map.br_blockcount;
 	}
+	return 0;
+}
 
+/*
+ * Remove the value associated with an attribute by deleting the
+ * out-of-line buffer that it is stored on.
+ */
+int
+xfs_attr_rmtval_remove(
+	struct xfs_da_args      *args)
+{
+	xfs_dablk_t		lblkno;
+	int			blkcnt;
+	int			error = 0;
+	int			done = 0;
+
+	trace_xfs_attr_rmtval_remove(args);
+
+	error = xfs_attr_rmtval_invalidate(args);
+	if (error)
+		return error;
 	/*
 	 * Keep de-allocating extents until the remote-value region is gone.
 	 */
 	lblkno = args->rmtblkno;
 	blkcnt = args->rmtblkcnt;
-	done = 0;
 	while (!done) {
 		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
 				    XFS_BMAPI_ATTRFORK, 1, &done);

fs/xfs/libxfs/xfs_attr_remote.h

@@ -13,5 +13,5 @@ int xfs_attr_rmtval_set(struct xfs_da_args *args);
 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);
 #endif /* __XFS_ATTR_REMOTE_H__ */