Re: [PATCH 4/6] block/gluster: Do not force-cap *pnum

[Max Reitz]

On 19.06.21 12:36, Vladimir Sementsov-Ogievskiy wrote:
> 17.06.2021 18:52, Max Reitz wrote:
> > bdrv_co_block_status() does it for us, we do not need to do it here.
> >
> > The advantage of not capping *pnum is that bdrv_co_block_status() can
> > cache larger data regions than requested by its caller.
> >
> > Signed-off-by: Max Reitz <mreitz@redhat.com>
>
>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
>
>
> > ---
> >   block/gluster.c | 7 ++++---
> >   1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/block/gluster.c b/block/gluster.c
> > index e8ee14c8e9..8ef7bb18d5 100644
> > --- a/block/gluster.c
> > +++ b/block/gluster.c
> > @@ -1461,7 +1461,8 @@ exit:
> >    * the specified offset) that are known to be in the same
> >    * allocated/unallocated state.
> >    *
> > - * 'bytes' is the max value 'pnum' should be set to.
> > + * 'bytes' is a soft cap for 'pnum'.  If the information is free, 
> > 'pnum' may
> > + * well exceed it.
> >    *
> >    * (Based on raw_co_block_status() from file-posix.c.)
> >    */
> > @@ -1500,12 +1501,12 @@ static int coroutine_fn 
> > qemu_gluster_co_block_status(BlockDriverState *bs,
> >       } else if (data == offset) {
> >           /* On a data extent, compute bytes to the end of the extent,
> >            * possibly including a partial sector at EOF. */
> > -        *pnum = MIN(bytes, hole - offset);
> > +        *pnum = hole - offset;
> >           ret = BDRV_BLOCK_DATA;
>
> Interesting, isn't it a bug that we don't ROUND_UP *pnum to 
> request_alignment here like it is done in file-posix ?

Guess I forgot gluster in 9c3db310ff0 O:)

I don’t think I’ll be able to reproduce it for gluster, but I suppose 
just doing the same thing for gluster should be fine...

Max