Re: [PATCH 3/3] Btrfs: add basic DIO read support

Josef Bacik
Fri, 07 May 2010 13:40:37 -0000

On Fri, May 07, 2010 at 10:55:37AM +0100, Jamie Lokier
wrote:
> Josef Bacik wrote:
> > 3) Lock the entire range during DIO.  I originally had it so we would
lock the
> > extents as get_block was called, and then unlock them as the endio
function was
> > called, which worked great, but if we ever had an error in the
submit_io hook,
> > we could have locked an extent that would never be submitted for IO,
so we
> > wouldn''t be able to unlock it, so this solution fixed that
problem and made it a
> > bit cleaner.
>
> Does this prevent concurrent DIOs to overlapping or nearby ranges?
>

It just prevents them from overlapping areas.  Thanks,

Josef