[XFS] Tight loop in xfs_finish_reclaim_all prevented the xfslogd to run

its queue of IO completion callbacks, thus creating the deadlock between
umount and xfslogd. Breaking the loop solves the problem.

SGI-PV: 943821
SGI-Modid: xfs-linux-melb:xfs-kern:202363a
Signed-off-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

fs/xfs/xfs_vnodeops.c

@@ -3958,8 +3958,9 @@ xfs_finish_reclaim_all(xfs_mount_t *mp, int noblock)
 				}
 			}
 			XFS_MOUNT_IUNLOCK(mp);
-			xfs_finish_reclaim(ip, noblock,
-				XFS_IFLUSH_DELWRI_ELSE_ASYNC);
+			if (xfs_finish_reclaim(ip, noblock,
+					XFS_IFLUSH_DELWRI_ELSE_ASYNC))
+				delay(1);
 			purged = 1;
 			break;
 		}