Re: review: fix remount vs barrier options

[Nathan Scott <nathans@sgi.com>]

On Sun, Jul 23, 2006 at 08:06:50PM +0100, Christoph Hellwig wrote:
> > It finally clicked that we are not clearing the buffer flag
> > from a previously written log buffer, even though we'll no
> > longer set a new flag into a buffer (due to the mount flag
> > being cleared), so we _can_ still issue barrier writes when
> > remounted without barriers.
> 
> That's true.  Ooops.
> 
> > This was made more complicated by the way a freshly mounted
> > filesystem with 8 log buffers wouldn't show up the problem,
> > since we have to slowly cycle through the "clear" log buffers
> > before we see the bug.  This seems like the simplest fix...
> > 
> > (Hmmm, actually, I wonder if this will also resolve the quota
> > log I/O problem that was reported the other day too).
> 
> Shouldn't we make sure we clear all flags when reusing a log buffer?
> Relying on clearing individual flags seems rather fragile to me.

*nod* - good idea.  I'll rework xlog_sync, and resend later.

thanks.

-- 
Nathan