btrfs: switch btrfs_ioctl_balance() to mnt_want_write_file()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0e92e57..1e9f6c0 100644 (file)
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3268,7 +3268,7 @@ static long btrfs_ioctl_balance(struct file *file, void __user *arg)
        if (fs_info->sb->s_flags & MS_RDONLY)
                return -EROFS;
 
-       ret = mnt_want_write(file->f_path.mnt);
+       ret = mnt_want_write_file(file);
        if (ret)
                return ret;
 
@@ -3338,7 +3338,7 @@ 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;
 }