On 05/14/2016 06:45 AM, Denis V. Lunev wrote: > From: Pavel Butsykin <pbutsy...@virtuozzo.com> > > This patch just adds the interface to the bdrv_co_write_compressed, which > is currently not used but will be useful for safe implementation of the > bdrv_co_write_compressed callback in format drivers. > > Signed-off-by: Pavel Butsykin <pbutsy...@virtuozzo.com> > Signed-off-by: Denis V. Lunev <d...@openvz.org> > CC: Jeff Cody <jc...@redhat.com> > CC: Markus Armbruster <arm...@redhat.com> > CC: Eric Blake <ebl...@redhat.com> > CC: John Snow <js...@redhat.com> > CC: Stefan Hajnoczi <stefa...@redhat.com> > CC: Kevin Wolf <kw...@redhat.com> > ---
> +++ b/block/io.c
> @@ -1828,8 +1828,8 @@ int bdrv_is_allocated_above(BlockDriverState *top,
> return 0;
> }
>
> -int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
> - const uint8_t *buf, int nb_sectors)
> +int bdrv_co_write_compressed(BlockDriverState *bs, int64_t sector_num,
> + int nb_sectors, QEMUIOVector *qiov)
As long as we're adding a new public interface, I'd really like us to
make it byte-based. int64_t sector_num might be better represented as a
byte offset, and int nb_sectors seems redundant with qiov->size.
> {
> BlockDriver *drv = bs->drv;
> int ret;
> @@ -1837,7 +1837,7 @@ int bdrv_write_compressed(BlockDriverState *bs, int64_t
> sector_num,
> if (!drv) {
> return -ENOMEDIUM;
> }
> - if (!drv->bdrv_write_compressed) {
> + if (!drv->bdrv_co_write_compressed) {
> return -ENOTSUP;
> }
> ret = bdrv_check_request(bs, sector_num, nb_sectors);
> @@ -1846,8 +1846,71 @@ int bdrv_write_compressed(BlockDriverState *bs,
> int64_t sector_num,
> }
>
> assert(QLIST_EMPTY(&bs->dirty_bitmaps));
> + assert(qemu_in_coroutine());
> +
> + return drv->bdrv_co_write_compressed(bs, sector_num, nb_sectors, qiov);
Of course, if you make the public interface byte-based, then calling
into the back end will have to scale back to sectors (after first
asserting that we aren't violating the scaling); see how Kevin did it in
commit 166fe9605.
> +}
> +
> +typedef struct BdrvWriteCompressedCo {
> + BlockDriverState *bs;
> + int64_t sector_num;
Again, I think a byte offset is smarter than a sector number.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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