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>

fs/xfs/xfs_buf_item.c

@@ -629,7 +629,7 @@ xfs_buf_item_push(
  * 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_item_pushbuf(
 
 	xfs_buf_delwri_promote(bp);
 	xfs_buf_relse(bp);
+	return true;
 }
 
 STATIC void

fs/xfs/xfs_dquot_item.c

@@ -183,13 +183,14 @@ xfs_qm_dqunpin_wait(
  * search the buffer cache can be a time consuming thing, and AIL lock is a
  * spinlock.
  */
-STATIC void
+STATIC bool
 xfs_qm_dquot_logitem_pushbuf(
 	struct xfs_log_item	*lip)
 {
 	struct xfs_dq_logitem	*qlip = DQUOT_ITEM(lip);
 	struct xfs_dquot	*dqp = qlip->qli_dquot;
 	struct xfs_buf		*bp;
+	bool			ret = true;
 
 	ASSERT(XFS_DQ_IS_LOCKED(dqp));
 
@@ -201,17 +202,20 @@ xfs_qm_dquot_logitem_pushbuf(
 	if (completion_done(&dqp->q_flush) ||
 	    !(lip->li_flags & XFS_LI_IN_AIL)) {
 		xfs_dqunlock(dqp);
-		return;
+		return true;
 	}
 
 	bp = xfs_incore(dqp->q_mount->m_ddev_targp, qlip->qli_format.qlf_blkno,
 			dqp->q_mount->m_quotainfo->qi_dqchunklen, XBF_TRYLOCK);
 	xfs_dqunlock(dqp);
 	if (!bp)
-		return;
+		return true;
 	if (XFS_BUF_ISDELAYWRITE(bp))
 		xfs_buf_delwri_promote(bp);
+	if (xfs_buf_ispinned(bp))
+		ret = false;
 	xfs_buf_relse(bp);
+	return ret;
 }
 
 /*

fs/xfs/xfs_inode_item.c

@@ -708,13 +708,14 @@ xfs_inode_item_committed(
  * marked delayed write. If that's the case, we'll promote it and that will
  * allow the caller to write the buffer by triggering the xfsbufd to run.
  */
-STATIC void
+STATIC bool
 xfs_inode_item_pushbuf(
 	struct xfs_log_item	*lip)
 {
 	struct xfs_inode_log_item *iip = INODE_ITEM(lip);
 	struct xfs_inode	*ip = iip->ili_inode;
 	struct xfs_buf		*bp;
+	bool			ret = true;
 
 	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED));
 
@@ -725,7 +726,7 @@ xfs_inode_item_pushbuf(
 	if (completion_done(&ip->i_flush) ||
 	    !(lip->li_flags & XFS_LI_IN_AIL)) {
 		xfs_iunlock(ip, XFS_ILOCK_SHARED);
-		return;
+		return true;
 	}
 
 	bp = xfs_incore(ip->i_mount->m_ddev_targp, iip->ili_format.ilf_blkno,
@@ -733,10 +734,13 @@ xfs_inode_item_pushbuf(
 
 	xfs_iunlock(ip, XFS_ILOCK_SHARED);
 	if (!bp)
-		return;
+		return true;
 	if (XFS_BUF_ISDELAYWRITE(bp))
 		xfs_buf_delwri_promote(bp);
+	if (xfs_buf_ispinned(bp))
+		ret = false;
 	xfs_buf_relse(bp);
+	return ret;
 }
 
 /*

fs/xfs/xfs_trans.h

@@ -350,7 +350,7 @@ typedef struct xfs_item_ops {
 	void (*iop_unlock)(xfs_log_item_t *);
 	xfs_lsn_t (*iop_committed)(xfs_log_item_t *, xfs_lsn_t);
 	void (*iop_push)(xfs_log_item_t *);
-	void (*iop_pushbuf)(xfs_log_item_t *);
+	bool (*iop_pushbuf)(xfs_log_item_t *);
 	void (*iop_committing)(xfs_log_item_t *, xfs_lsn_t);
 } xfs_item_ops_t;
 

fs/xfs/xfs_trans_ail.c

@@ -427,8 +427,13 @@ xfs_ail_worker(
 
 		case XFS_ITEM_PUSHBUF:
 			XFS_STATS_INC(xs_push_ail_pushbuf);
-			IOP_PUSHBUF(lip);
+
+			if (!IOP_PUSHBUF(lip)) {
+				stuck++;
+				flush_log = 1;
+			} else {
 				ailp->xa_last_pushed_lsn = lsn;
+			}
 			push_xfsbufd = 1;
 			break;