xfs: force the log if we encounter pinned buffers in .iop_pushbuf

We need to check for pinned buffers even in .iop_pushbuf given that inode
items flush into the same buffers that may be pinned directly due operations
on the unlinked inode list operating directly on buffers.  To do this add a
return value to .iop_pushbuf that tells the AIL push about this and use
the existing log force mechanisms to unpin it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Stefan Priebe <s.priebe@profihost.ag>
Tested-by: Stefan Priebe <s.priebe@profihost.ag>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>


diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index cac2ecf..ef43fce 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -629,7 +629,7 @@
  * the xfsbufd to get this buffer written. We have to unlock the buffer
  * to allow the xfsbufd to write it, too.
  */
-STATIC void
+STATIC bool
 xfs_buf_item_pushbuf(
 	struct xfs_log_item	*lip)
 {
@@ -643,6 +643,7 @@
 
 	xfs_buf_delwri_promote(bp);
 	xfs_buf_relse(bp);
+	return true;
 }
 
 STATIC void