Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfs

* 'for-linus' of git://oss.sgi.com/xfs/xfs:
  xfs: remove incorrect assert in xfs_vm_writepage
  xfs: use hlist_add_fake
  xfs: fix a few compiler warnings with CONFIG_XFS_QUOTA=n
  xfs: tell lockdep about parent iolock usage in filestreams
  xfs: move delayed write buffer trace
  xfs: fix per-ag reference counting in inode reclaim tree walking
  xfs: xfs_ioctl: fix information leak to userland
  xfs: remove experimental tag from the delaylog option

1 files changed, 7 insertions, 1 deletions

diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
index 9b715dce5699..9124425b7f2f 100644
--- a/fs/xfs/xfs_filestream.c
+++ b/fs/xfs/xfs_filestream.c
@@ -744,9 +744,15 @@ xfs_filestream_new_ag(
 	 * If the file's parent directory is known, take its iolock in exclusive
 	 * mode to prevent two sibling files from racing each other to migrate
 	 * themselves and their parent to different AGs.
+	 *
+	 * Note that we lock the parent directory iolock inside the child
+	 * iolock here.  That's fine as we never hold both parent and child
+	 * iolock in any other place.  This is different from the ilock,
+	 * which requires locking of the child after the parent for namespace
+	 * operations.
 	 */
 	if (pip)
-		xfs_ilock(pip, XFS_IOLOCK_EXCL);
+		xfs_ilock(pip, XFS_IOLOCK_EXCL | XFS_IOLOCK_PARENT);
 
 	/*
 	 * A new AG needs to be found for the file.  If the file's parent