From: Sage Weil <sage@newdream.net>
Date: Fri, 29 Oct 2010 19:37:33 +0000 (-0400)
Subject: Btrfs: fix lockdep warning on clone ioctl
X-Git-Tag: upstream/snapshot3+hdmi~11282^2~104
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=fccdae435c1b295cca546f23f6f43126a28ffac3;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

Btrfs: fix lockdep warning on clone ioctl

I'm no lockdep expert, but this appears to make the lockdep warning go
away for the i_mutex locking in the clone ioctl.

Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3fe15e4..93d69b3 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1492,11 +1492,11 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd,
 	path->reada = 2;
 
 	if (inode < src) {
-		mutex_lock(&inode->i_mutex);
-		mutex_lock(&src->i_mutex);
+		mutex_lock_nested(&inode->i_mutex, I_MUTEX_PARENT);
+		mutex_lock_nested(&src->i_mutex, I_MUTEX_CHILD);
 	} else {
-		mutex_lock(&src->i_mutex);
-		mutex_lock(&inode->i_mutex);
+		mutex_lock_nested(&src->i_mutex, I_MUTEX_PARENT);
+		mutex_lock_nested(&inode->i_mutex, I_MUTEX_CHILD);
 	}
 
 	/* determine range to clone */