From: Dave Chinner <david@fromorbit.com>
To: Brian Foster <bfoster@redhat.com>
Cc: sage@redhat.com, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: optimise away log forces on timestamp updates for fdatasync
Date: Tue, 27 Oct 2015 07:54:04 +1100 [thread overview]
Message-ID: <20151026205404.GH8773@dastard> (raw)
In-Reply-To: <20151026114929.GA59738@bfoster.bfoster>
On Mon, Oct 26, 2015 at 07:49:29AM -0400, Brian Foster wrote:
> On Mon, Oct 26, 2015 at 04:07:20PM +1100, Dave Chinner wrote:
> > > Also, is it me or are we sending an unconditional flush in the hunk
> > > following the log force call in xfs_file_fsync() (even if we've skipped
> > > the log force)?
> >
> > The flush is needed - fdatasync needs to guarantee the data is
> > on stable storage even if no metadata needs to be written to the
> > journal.
> >
>
> Ok. Well it's too bad we don't get any feedback about what was written
> from the filemap_write_and_wait_range() call. As it is, we send a flush
> even if there's nothing to write back.
Direct IO still needs cache flushes.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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prev parent reply other threads:[~2015-10-26 20:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-21 2:59 [PATCH] xfs: optimise away log forces on timestamp updates for fdatasync Dave Chinner
2015-10-22 17:36 ` Brian Foster
2015-10-26 5:07 ` Dave Chinner
2015-10-26 11:49 ` Brian Foster
2015-10-26 20:54 ` Dave Chinner [this message]
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