On Fri, Feb 01, 2019 at 10:21:20PM +0100, Jan Kara wrote:
> On Thu 31-01-19 23:42:19, Theodore Ts'o wrote:
> > This reverts commit ad211f3e94b314a910d4af03178a0b52a7d1ee0a.
> >
> > As Jan Kara pointed out, this change was unsafe since it means we lose
> > the call to sync_mapping_buffers() in the nojournal case. The
> > original point of the commit was avoid taking the inode mutex (since
> > it causes a lockdep warning in generic/113); but we need the mutex in
> > order to call sync_mapping_buffers().
>
> Actually, I don't think sync_mapping_buffers() needs inode mutex (i_rwsem
> these days). It uses blkdev_mapping->private_lock for synchronization of
> operations on the list of buffers and fsync_buffers_list() seems to be
> pretty careful about races with mark_buffer_dirty_inode(). So why do you
> think we need i_rwsem?
Hmm, I think you're right. I wonder if we can therefore remove the
inode_lock() in __generic_file_fsync() then... What do you think?
- Ted
