From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50396) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bFhEc-0003xt-54 for qemu-devel@nongnu.org; Wed, 22 Jun 2016 08:26:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bFhEX-0002Dc-TC for qemu-devel@nongnu.org; Wed, 22 Jun 2016 08:26:21 -0400 Received: from mail-am1on0127.outbound.protection.outlook.com ([157.56.112.127]:7968 helo=emea01-am1-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bFhEX-0002Cs-6c for qemu-devel@nongnu.org; Wed, 22 Jun 2016 08:26:17 -0400 References: <1464686130-12265-1-git-send-email-den@openvz.org> <1464686130-12265-3-git-send-email-den@openvz.org> <575EC3E2.1010304@redhat.com> From: Pavel Butsykin Message-ID: <576A83DF.6060202@virtuozzo.com> Date: Wed, 22 Jun 2016 15:26:07 +0300 MIME-Version: 1.0 In-Reply-To: <575EC3E2.1010304@redhat.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 02/11] block/io: add bdrv_co_write_compressed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake , "Denis V. Lunev" , qemu-devel@nongnu.org Cc: Jeff Cody , Markus Armbruster , John Snow , Stefan Hajnoczi , Kevin Wolf On 13.06.2016 17:32, Eric Blake wrote: > On 05/31/2016 03:15 AM, Denis V. Lunev wrote: >> From: Pavel Butsykin >> >> This patch just adds the interface to the bdrv_co_pwritev_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 >> Signed-off-by: Denis V. Lunev >> CC: Jeff Cody >> CC: Markus Armbruster >> CC: Eric Blake >> CC: John Snow >> CC: Stefan Hajnoczi >> CC: Kevin Wolf >> --- >> block/io.c | 78 +++++++++++++++++++++++++++++++++++++++++++---- >> include/block/block_int.h | 5 +++ >> qemu-img.c | 2 +- >> 3 files changed, 78 insertions(+), 7 deletions(-) >> >> diff --git a/block/io.c b/block/io.c >> index c5bb6ae..54cd9a4 100644 >> --- a/block/io.c >> +++ b/block/io.c >> @@ -1779,8 +1779,8 @@ int bdrv_is_allocated_above(BlockDriverState *top, >> return 0; >> } >> >> -int bdrv_pwrite_compressed(BlockDriverState *bs, int64_t offset, >> - const void *buf, int count) >> +int coroutine_fn bdrv_co_pwritev_compressed(BlockDriverState *bs, >> + int64_t offset, unsigned int bytes, QEMUIOVector *qiov) > > Why the rename s/count/bytes/? Would it be better to get the name right > in 1/11? It made like the bdrv_co_pwritev interface. For the bdrv_pwrite_compressed() func also need rename s/count/bytes/ in 1/11. >> { >> BlockDriver *drv = bs->drv; >> int ret; >> @@ -1788,18 +1788,84 @@ int bdrv_pwrite_compressed(BlockDriverState *bs, int64_t offset, >> if (!drv) { >> return -ENOMEDIUM; >> } >> - if (!drv->bdrv_write_compressed) { >> + >> + if (!drv->bdrv_co_write_compressed) { >> return -ENOTSUP; > > This is a (temporary) regression - since none of the drivers have > .bdrv_co_write_compressed yet, you will always fail. Rather, the > transition period should support both interfaces at once... > >> } >> - ret = bdrv_check_byte_request(bs, offset, count); >> + >> + ret = bdrv_check_byte_request(bs, offset, bytes); >> if (ret < 0) { >> return ret; >> } >> >> assert(QLIST_EMPTY(&bs->dirty_bitmaps)); >> + assert(qemu_in_coroutine()); >> + >> + return drv->bdrv_co_write_compressed(bs, offset >> BDRV_SECTOR_BITS, >> + bytes >> BDRV_SECTOR_BITS, qiov); > > ...and call into either the old or the new interface according to what > is present. > > >> +int bdrv_pwrite_compressed(BlockDriverState *bs, int64_t offset, >> + const void *buf, int count) >> +{ >> + BdrvWriteCompressedCo data; >> + QEMUIOVector qiov; >> + BlockDriver *drv = bs->drv; >> + struct iovec iov = { >> + .iov_base = (void *)buf, >> + .iov_len = count, >> + }; >> + qemu_iovec_init_external(&qiov, &iov, 1); >> >> - return drv->bdrv_write_compressed(bs, offset >> BDRV_SECTOR_BITS, buf, >> - count >> BDRV_SECTOR_BITS); >> + data = (BdrvWriteCompressedCo) { >> + .bs = bs, >> + .offset = offset, >> + .qiov = &qiov, >> + .ret = -EINPROGRESS, >> + }; >> + >> + if (!drv) { >> + return -ENOMEDIUM; >> + } >> + >> + if (drv->bdrv_write_compressed) { >> + int ret = bdrv_check_byte_request(bs, offset, count); >> + if (ret < 0) { >> + return ret; >> + } >> + assert(QLIST_EMPTY(&bs->dirty_bitmaps)); >> + return drv->bdrv_write_compressed(bs, offset >> BDRV_SECTOR_BITS, buf, >> + count >> BDRV_SECTOR_BITS); >> + } > > Oh, you're catering to the old code up front, without a coroutine, and > only the new code gets coroutine treatment. Maybe it's okay after all. Yes, it is made for a gradual transition from drv->bdrv_write_compressed to drv->bdrv_co_write_compressed. >> + >> + if (qemu_in_coroutine()) { >> + /* Fast-path if already in coroutine context */ >> + bdrv_write_compressed_co_entry(&data); >> + } else { >> + AioContext *aio_context = bdrv_get_aio_context(bs); >> + >> + Coroutine *co = qemu_coroutine_create(bdrv_write_compressed_co_entry); >> + qemu_coroutine_enter(co, &data); >> + while (data.ret == -EINPROGRESS) { >> + aio_poll(aio_context, true); >> + } >> + } >> + return data.ret; >> } >> >> int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf, >> diff --git a/include/block/block_int.h b/include/block/block_int.h >> index 30a9717..ccba9c9 100644 >> --- a/include/block/block_int.h >> +++ b/include/block/block_int.h >> @@ -207,6 +207,9 @@ struct BlockDriver { >> int (*bdrv_write_compressed)(BlockDriverState *bs, int64_t sector_num, >> const uint8_t *buf, int nb_sectors); >> >> + int coroutine_fn (*bdrv_co_write_compressed)(BlockDriverState *bs, > > Might be better to name this bdrv_co_pwrite_compressed if we want to > make it byte-based... > >> + int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); > > ...it seems odd that you have to add a new sector-based interface given > that you are trying to convert to byte-based. > When I sent this patch, Kevin had not yet converted the sector-based interfaces to byte-based for format drivers :) >> + >> int (*bdrv_snapshot_create)(BlockDriverState *bs, >> QEMUSnapshotInfo *sn_info); >> int (*bdrv_snapshot_goto)(BlockDriverState *bs, >> @@ -535,6 +538,8 @@ int coroutine_fn bdrv_co_preadv(BlockDriverState *bs, >> int coroutine_fn bdrv_co_pwritev(BlockDriverState *bs, >> int64_t offset, unsigned int bytes, QEMUIOVector *qiov, >> BdrvRequestFlags flags); >> +int coroutine_fn bdrv_co_pwritev_compressed(BlockDriverState *bs, >> + int64_t offset, unsigned int bytes, QEMUIOVector *qiov); >> >> int get_tmp_filename(char *filename, int size); >> BlockDriver *bdrv_probe_all(const uint8_t *buf, int buf_size, >> diff --git a/qemu-img.c b/qemu-img.c >> index eb744d4..ab54027 100644 >> --- a/qemu-img.c >> +++ b/qemu-img.c >> @@ -2024,7 +2024,7 @@ static int img_convert(int argc, char **argv) >> const char *preallocation = >> qemu_opt_get(opts, BLOCK_OPT_PREALLOC); >> >> - if (!drv->bdrv_write_compressed) { >> + if (!drv->bdrv_write_compressed && !drv->bdrv_co_write_compressed) { >> error_report("Compression not supported for this file format"); >> ret = -1; >> goto out; >> >