Btrfs: use mnt_want_write_file instead of mnt_want_write

mnt_want_write_file is faster when file has been opened for write.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b8034dc62e38..13ed1c9534cc 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3265,7 +3265,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
         if (!capable(CAP_SYS_ADMIN))
                 return -EPERM;
 
-        ret = mnt_want_write(file->f_path.mnt);
+        ret = mnt_want_write_file(file);
         if (ret)
                 return ret;
 
@@ -3335,7 +3335,7 @@ out_bargs:
 out:
         mutex_unlock(&fs_info->balance_mutex);
         mutex_unlock(&fs_info->volume_mutex);
-        mnt_drop_write(file->f_path.mnt);
+        mnt_drop_write_file(file);
         return ret;
 }