1 files changed, 29 insertions, 6 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index e22f0057d21f..594cd822d84d 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -425,8 +425,7 @@ xfs_quiesce_attr(
 	/* Push the superblock and write an unmount record */
 	error = xfs_log_sbcount(mp, 1);
 	if (error)
-		xfs_fs_cmn_err(CE_WARN, mp,
-				"xfs_attr_quiesce: failed to log sb changes. "
+		xfs_warn(mp, "xfs_attr_quiesce: failed to log sb changes. "
 				"Frozen image may not be consistent.");
 	xfs_log_unmount_write(mp);
 	xfs_unmountfs_writesb(mp);
@@ -762,8 +761,10 @@ xfs_reclaim_inode(
 	struct xfs_perag	*pag,
 	int			sync_mode)
 {
-	int	error = 0;
+	int	error;
 
+restart:
+	error = 0;
 	xfs_ilock(ip, XFS_ILOCK_EXCL);
 	if (!xfs_iflock_nowait(ip)) {
 		if (!(sync_mode & SYNC_WAIT))
@@ -789,9 +790,31 @@ xfs_reclaim_inode(
 	if (xfs_inode_clean(ip))
 		goto reclaim;
 
-	/* Now we have an inode that needs flushing */
-	error = xfs_iflush(ip, sync_mode);
+	/*
+	 * Now we have an inode that needs flushing.
+	 *
+	 * We do a nonblocking flush here even if we are doing a SYNC_WAIT
+	 * reclaim as we can deadlock with inode cluster removal.
+	 * xfs_ifree_cluster() can lock the inode buffer before it locks the
+	 * ip->i_lock, and we are doing the exact opposite here. As a result,
+	 * doing a blocking xfs_itobp() to get the cluster buffer will result
+	 * in an ABBA deadlock with xfs_ifree_cluster().
+	 *
+	 * As xfs_ifree_cluser() must gather all inodes that are active in the
+	 * cache to mark them stale, if we hit this case we don't actually want
+	 * to do IO here - we want the inode marked stale so we can simply
+	 * reclaim it. Hence if we get an EAGAIN error on a SYNC_WAIT flush,
+	 * just unlock the inode, back off and try again. Hopefully the next
+	 * pass through will see the stale flag set on the inode.
+	 */
+	error = xfs_iflush(ip, SYNC_TRYLOCK | sync_mode);
 	if (sync_mode & SYNC_WAIT) {
+		if (error == EAGAIN) {
+			xfs_iunlock(ip, XFS_ILOCK_EXCL);
+			/* backoff longer than in xfs_ifree_cluster */
+			delay(2);
+			goto restart;
+		}
 		xfs_iflock(ip);
 		goto reclaim;
 	}
@@ -806,7 +829,7 @@ xfs_reclaim_inode(
 	 * pass on the error.
 	 */
 	if (error && error != EAGAIN && !XFS_FORCED_SHUTDOWN(ip->i_mount)) {
-		xfs_fs_cmn_err(CE_WARN, ip->i_mount,
+		xfs_warn(ip->i_mount,
 			"inode 0x%llx background reclaim flush failed with %d",
 			(long long)ip->i_ino, error);
 	}