Btrfs: fix ctime update of on-disk inode

To reproduce the bug:

    # touch /mnt/tmp
    # stat /mnt/tmp | grep Change
    Change: 2011-12-09 09:32:23.412105981 +0800
    # chattr +i /mnt/tmp
    # stat /mnt/tmp | grep Change
    Change: 2011-12-09 09:32:43.198105295 +0800
    # umount /mnt
    # mount /dev/loop1 /mnt
    # stat /mnt/tmp | grep Change
    Change: 2011-12-09 09:32:23.412105981 +0800

We should update ctime of in-memory inode before calling
btrfs_update_inode().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 72d461656f60..40eaa9fdf07c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -252,11 +252,11 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
         trans = btrfs_join_transaction(root);
         BUG_ON(IS_ERR(trans));
 
+        btrfs_update_iflags(inode);
+        inode->i_ctime = CURRENT_TIME;
         ret = btrfs_update_inode(trans, root, inode);
         BUG_ON(ret);
 
-        btrfs_update_iflags(inode);
-        inode->i_ctime = CURRENT_TIME;
         btrfs_end_transaction(trans, root);
 
         mnt_drop_write(file->f_path.mnt);