xfs: fix btree cursor error cleanups

The btree cursor cleanup function takes an error parameter that
affects how buffers are released from the cursor. All buffers are
released in the event of error. Several callers do not specify the
XFS_BTREE_ERROR flag in the event of error, however. This can cause
buffers to hang around locked or with an elevated hold count and
thus lead to umount hangs in the event of errors.

Fix up the xfs_btree_del_cursor() callers to pass XFS_BTREE_ERROR if
the cursor is being torn down due to error.
Signed-off-by: NBrian Foster <bfoster@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>

fs/xfs/libxfs/xfs_ialloc.c

@@ -2232,7 +2232,7 @@ xfs_imap_lookup(
 	}
 
 	xfs_trans_brelse(tp, agbp);
-	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
+	xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
 	if (error)
 		return error;
 

fs/xfs/xfs_itable.c

@@ -473,7 +473,8 @@ xfs_bulkstat(
 		 * pending error, then we are done.
 		 */
 del_cursor:
-		xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
+		xfs_btree_del_cursor(cur, error ?
+					  XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
 		xfs_buf_relse(agbp);
 		if (error)
 			break;