2 files changed, 16 insertions, 1 deletions

diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c
index 760f4c5b5160..75b0cd4da0ea 100644
--- a/fs/xfs/xfs_dfrag.c
+++ b/fs/xfs/xfs_dfrag.c
@@ -149,7 +149,14 @@ xfs_swap_extents(
 
         sbp = &sxp->sx_stat;
 
-        xfs_lock_two_inodes(ip, tip, lock_flags);
+        /*
+         * we have to do two separate lock calls here to keep lockdep
+         * happy. If we try to get all the locks in one call, lock will
+         * report false positives when we drop the ILOCK and regain them
+         * below.
+         */
+        xfs_lock_two_inodes(ip, tip, XFS_IOLOCK_EXCL);
+        xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
         locked = 1;
 
         /* Verify that both files have the same format */
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index aa238c8fbd7a..98a0aecafddc 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -1838,6 +1838,12 @@ again:
 #endif
 }
 
+/*
+ * xfs_lock_two_inodes() can only be used to lock one type of lock
+ * at a time - the iolock or the ilock, but not both at once. If
+ * we lock both at once, lockdep will report false positives saying
+ * we have violated locking orders.
+ */
 void
 xfs_lock_two_inodes(
         xfs_inode_t             *ip0,
@@ -1848,6 +1854,8 @@ xfs_lock_two_inodes(
         int                     attempts = 0;
         xfs_log_item_t          *lp;
 
+        if (lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL))
+                ASSERT((lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)) == 0);
         ASSERT(ip0->i_ino != ip1->i_ino);
 
         if (ip0->i_ino > ip1->i_ino) {