writeback: add missing requeue_io in writeback_inodes_wb

In "writeback: fix writeback_inodes_wb from writeback_inodes_sb" I
accidentally removed the requeue_io if we need to skip a superblock
because we can't pin it.  Add it back, otherwise we're getting spurious
lockups after multiple xfstests runs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 0079bf59b583..3a066e91ec8d 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -643,8 +643,10 @@ static void writeback_inodes_wb(struct bdi_writeback *wb,
 
                         ret = writeback_sb_inodes(sb, wb, wbc);
                 } else {
-                        if (!pin_sb_for_writeback(sb))
+                        if (!pin_sb_for_writeback(sb)) {
+                                requeue_io(inode);
                                 continue;
+                        }
                         ret = writeback_sb_inodes(sb, wb, wbc);
                         drop_super(sb);
                 }