Re: [PATCH 2/7] ext3: call blkdev_issue_flush() on fsync()

Jens Axboe
2009-03-31T11:18:31Z

On Tue, Mar 31 2009, Tejun Heo wrote:
> Hello,
>
> Theodore Tso wrote:
> > On Mon, Mar 30, 2009 at 10:15:51AM -0400, Chris Mason wrote:
> >> I'm not sure we want to stick Fernando with changing how barriers are
> >> done in individual filesystems, his patch is just changing the existing
> >> call points.
> >
> > Well, his patch actually added some calls to block_issue_flush(). But
> > yes, it's probably better if he just changes the existing call points,
> > and we can have the relevant filesystem maintainers double check to
> > make sure that there aren't any new call points which are needed.
>
> How about having something like blk_ensure_cache_flushed() which
> issues flush iff there hasn't been any write since the last flush?
> It'll be easy to implement and will filter out duplicate flushes in
> most cases.

My original ide implementation of flushes actually did this. My memory
is a little hazy on why it was dropped, I'm guessing because it
basically never triggered anyway.

--
Jens Axboe