Re: [Qemu-devel] [PATCH v2 13/24] block: Introduce bdrv_co_do_pwritev()

[Fam Zheng]

On Thu, 01/16 13:25, Kevin Wolf wrote:
> Am 13.12.2013 um 14:22 hat Kevin Wolf geschrieben:
> > This is going to become the bdrv_co_do_preadv() equivalent for writes.
> > In this patch, however, just a function taking byte offsets is created,
> > it doesn't align anything yet.
> > 
> > Signed-off-by: Kevin Wolf <address@hidden>
> > ---
> >  block.c | 23 +++++++++++++++++------
> >  1 file changed, 17 insertions(+), 6 deletions(-)
> > 
> > diff --git a/block.c b/block.c
> > index 385fb8a..a80db2e 100644
> > --- a/block.c
> > +++ b/block.c
> > @@ -3010,8 +3010,8 @@ static int coroutine_fn 
> > bdrv_aligned_pwritev(BlockDriverState *bs,
> >  /*
> >   * Handle a write request in coroutine context
> >   */
> > -static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
> > -    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
> > +static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
> > +    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
> >      BdrvRequestFlags flags)
> >  {
> >      int ret;
> > @@ -3022,21 +3022,32 @@ static int coroutine_fn 
> > bdrv_co_do_writev(BlockDriverState *bs,
> >      if (bs->read_only) {
> >          return -EACCES;
> >      }
> > -    if (bdrv_check_request(bs, sector_num, nb_sectors)) {
> > +    if (bdrv_check_byte_request(bs, offset, bytes)) {
> >          return -EIO;
> >      }
> >  
> >      /* throttling disk I/O */
> >      if (bs->io_limits_enabled) {
> > -        bdrv_io_limits_intercept(bs, nb_sectors, true);
> > +        bdrv_io_limits_intercept(bs, bytes << BDRV_SECTOR_BITS, true);
> >      }
> 
> Oh nice, this shifts in the wrong direction.
> 
> If somebody feels like writing a test case, something testing that I/O
> throttling actually throttles would be useful...
> 

Good idea. Should be possible for a basic test in qemu-iotests. I'll give it a
try.

Thanks,
Fam