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Date: Fri, 29 Apr 2016 11:49:32 +0200
From: Kevin Wolf <kwolf@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v2 13/17] vmdk: Implement
 .bdrv_co_pwritev() interface
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To: Pavel Butsykin <pbutsykin@virtuozzo.com>
Cc: Fam Zheng <famz@redhat.com>, qemu-devel@nongnu.org, sw@weilnetz.de, stefanha@redhat.com, qemu-block@nongnu.org, mreitz@redhat.com

Am 29.04.2016 um 10:49 hat Pavel Butsykin geschrieben:
> On 29.04.2016 06:08, Fam Zheng wrote:
> >On Thu, 04/28 15:16, Kevin Wolf wrote:
> >>  static int vmdk_write_compressed(BlockDriverState *bs,
> >>                                   int64_t sector_num,
> >>                                   const uint8_t *buf,
> >>                                   int nb_sectors)
> >>  {
> >>      BDRVVmdkState *s = bs->opaque;
> >>+
> >>      if (s->num_extents == 1 && s->extents[0].compressed) {
> >>-        return vmdk_write(bs, sector_num, buf, nb_sectors, false, false);
> >>+        Coroutine *co;
> >>+        AioContext *aio_context = bdrv_get_aio_context(bs);
> >>+        VmdkWriteCompressedCo data = {
> >>+            .bs         = bs,
> >>+            .sector_num = sector_num,
> >>+            .buf        = buf,
> >>+            .nb_sectors = nb_sectors,
> >>+            .ret        = -EINPROGRESS,
> >>+        };
> >>+        co = qemu_coroutine_create(vmdk_co_write_compressed);
> >>+        qemu_coroutine_enter(co, &data);
> >>+        while (data.ret == -EINPROGRESS) {
> >>+            aio_poll(aio_context, true);
> >>+        }
> >>+        return data.ret;
> >
> >Don't you have a plan to make the creation of coroutine for compressed write in
> >in block layer?  Or will bdrv_co_pwritev gain a "compressed" flag
> >(BDRV_REQ_COMPRESSED) in the future?
> >
> Actually, I already have these patches as part of the issue of backup
> compression, hope to send today.

Sounds good. Do you use a new flag for the normal write functions or just
update the existing .bdrv_write_compressed function?

Also, please base your series on this one to avoid merge conflicts in
vmdk.c. I'm going to apply the series to block-next now as it's fully
reveiwed. I guess you'll effectively need to revert what this patch does
to vmdk_write_compressed() in favour of a block/io.c solution.

Kevin