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TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 200AF308FC4E; Wed, 31 Jul 2019 13:39:22 +0000 (UTC) Received: from [10.10.123.215] (ovpn-123-215.rdu2.redhat.com [10.10.123.215]) by smtp.corp.redhat.com (Postfix) with ESMTP id F1C2960BEC; Wed, 31 Jul 2019 13:39:20 +0000 (UTC) To: Vladimir Sementsov-Ogievskiy , "qemu-devel@nongnu.org" , "qemu-block@nongnu.org" References: <20190724094025.12442-1-vsementsov@virtuozzo.com> <1977e825-0a1f-e575-2ffa-0ea8c65531bb@redhat.com> From: John Snow Openpgp: preference=signencrypt Autocrypt: addr=jsnow@redhat.com; prefer-encrypt=mutual; keydata= mQINBFTKefwBEAChvwqYC6saTzawbih87LqBYq0d5A8jXYXaiFMV/EvMSDqqY4EY6whXliNO IYzhgrPEe7ZmPxbCSe4iMykjhwMh5byIHDoPGDU+FsQty2KXuoxto+ZdrP9gymAgmyqdk3aV vzzmCa3cOppcqKvA0Kqr10UeX/z4OMVV390V+DVWUvzXpda45/Sxup57pk+hyY52wxxjIqef rj8u5BN93s5uCVTus0oiVA6W+iXYzTvVDStMFVqnTxSxlpZoH5RGKvmoWV3uutByQyBPHW2U 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List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "kwolf@redhat.com" , "mreitz@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/31/19 6:28 AM, Vladimir Sementsov-Ogievskiy wrote: > 30.07.2019 22:11, John Snow wrote: >> >> >> On 7/24/19 5:40 AM, Vladimir Sementsov-Ogievskiy wrote: >>> Instead of draining additional nodes in each job code, let's do it in >>> common block_job_drain, draining just all job's children. >>> BlockJobDriver.drain becomes unused, so, drop it at all. >>> >>> It's also a first step to finally get rid of blockjob->blk. >>> >>> Signed-off-by: Vladimir Sementsov-Ogievskiy >>> --- >>> >>> v3: just resend, as I've some auto returned mails and not sure that >>> v2 reached recipients. >>> >>> v2: apply Max's suggestions: >>> - drop BlockJobDriver.drain >>> - do firtly loop of bdrv_drained_begin and then separate loop >>> of bdrv_drained_end. >>> >>> Hmm, a question here: should I call bdrv_drained_end in reverse >>> order? Or it's OK as is? >>> >> >> I think it should be OK. These nodes don't necessarily have a well >> defined relationship between each other, do they? >> >>> include/block/blockjob_int.h | 11 ----------- >>> block/backup.c | 18 +----------------- >>> block/mirror.c | 26 +++----------------------- >>> blockjob.c | 13 ++++++++----- >>> 4 files changed, 12 insertions(+), 56 deletions(-) >>> >> >> Nice diffstat :) >> >>> diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h >>> index e4a318dd15..e1abf4ee85 100644 >>> --- a/include/block/blockjob_int.h >>> +++ b/include/block/blockjob_int.h >>> @@ -52,17 +52,6 @@ struct BlockJobDriver { >>> * besides job->blk to the new AioContext. >>> */ >>> void (*attached_aio_context)(BlockJob *job, AioContext *new_context); >>> - >>> - /* >>> - * If the callback is not NULL, it will be invoked when the job has to be >>> - * synchronously cancelled or completed; it should drain BlockDriverStates >>> - * as required to ensure progress. >>> - * >>> - * Block jobs must use the default implementation for job_driver.drain, >>> - * which will in turn call this callback after doing generic block job >>> - * stuff. >>> - */ >>> - void (*drain)(BlockJob *job); >> >> I was about to say "huh?" ... but then realized you're deleting this >> confusing glob. Good. >> >>> }; >>> >>> /** >>> diff --git a/block/backup.c b/block/backup.c >>> index 715e1d3be8..7930004bbd 100644 >>> --- a/block/backup.c >>> +++ b/block/backup.c >>> @@ -320,21 +320,6 @@ void backup_do_checkpoint(BlockJob *job, Error **errp) >>> hbitmap_set(backup_job->copy_bitmap, 0, backup_job->len); >>> } >>> >>> -static void backup_drain(BlockJob *job) >>> -{ >>> - BackupBlockJob *s = container_of(job, BackupBlockJob, common); >>> - >>> - /* Need to keep a reference in case blk_drain triggers execution >>> - * of backup_complete... >>> - */ >>> - if (s->target) { >>> - BlockBackend *target = s->target; >>> - blk_ref(target); >>> - blk_drain(target); >>> - blk_unref(target); >>> - } >>> -} >>> - >> >> Adios ... >> >>> static BlockErrorAction backup_error_action(BackupBlockJob *job, >>> bool read, int error) >>> { >>> @@ -493,8 +478,7 @@ static const BlockJobDriver backup_job_driver = { >>> .commit = backup_commit, >>> .abort = backup_abort, >>> .clean = backup_clean, >>> - }, >>> - .drain = backup_drain, >>> + } >>> }; >>> >> >> This pleases the eyes. >> >>> static int64_t backup_calculate_cluster_size(BlockDriverState *target, >>> diff --git a/block/mirror.c b/block/mirror.c >>> index 8cb75fb409..8456ccd89d 100644 >>> --- a/block/mirror.c >>> +++ b/block/mirror.c >>> @@ -644,14 +644,11 @@ static int mirror_exit_common(Job *job) >>> bdrv_ref(mirror_top_bs); >>> bdrv_ref(target_bs); >>> >>> - /* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before >>> + /* >>> + * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before >> >> (Thanks, patchew...) >> >>> * inserting target_bs at s->to_replace, where we might not be able to get >>> * these permissions. >>> - * >>> - * Note that blk_unref() alone doesn't necessarily drop permissions because >>> - * we might be running nested inside mirror_drain(), which takes an extra >>> - * reference, so use an explicit blk_set_perm() first. */ >>> - blk_set_perm(s->target, 0, BLK_PERM_ALL, &error_abort); >>> + */ >>> blk_unref(s->target); >>> s->target = NULL; >>> >>> @@ -1143,21 +1140,6 @@ static bool mirror_drained_poll(BlockJob *job) >>> return !!s->in_flight; >>> } >>> >>> -static void mirror_drain(BlockJob *job) >>> -{ >>> - MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); >>> - >>> - /* Need to keep a reference in case blk_drain triggers execution >>> - * of mirror_complete... >>> - */ >>> - if (s->target) { >>> - BlockBackend *target = s->target; >>> - blk_ref(target); >>> - blk_drain(target); >>> - blk_unref(target); >>> - } >>> -} >>> - >>> static const BlockJobDriver mirror_job_driver = { >>> .job_driver = { >>> .instance_size = sizeof(MirrorBlockJob), >>> @@ -1172,7 +1154,6 @@ static const BlockJobDriver mirror_job_driver = { >>> .complete = mirror_complete, >>> }, >>> .drained_poll = mirror_drained_poll, >>> - .drain = mirror_drain, >>> }; >>> >>> static const BlockJobDriver commit_active_job_driver = { >>> @@ -1189,7 +1170,6 @@ static const BlockJobDriver commit_active_job_driver = { >>> .complete = mirror_complete, >>> }, >>> .drained_poll = mirror_drained_poll, >>> - .drain = mirror_drain, >>> }; >>> >>> static void coroutine_fn >>> diff --git a/blockjob.c b/blockjob.c >>> index 20b7f557da..78cf71d6c8 100644 >>> --- a/blockjob.c >>> +++ b/blockjob.c >>> @@ -92,12 +92,15 @@ void block_job_free(Job *job) >>> void block_job_drain(Job *job) >>> { >>> BlockJob *bjob = container_of(job, BlockJob, job); >>> - const JobDriver *drv = job->driver; >>> - BlockJobDriver *bjdrv = container_of(drv, BlockJobDriver, job_driver); >>> + GSList *l; >>> >>> - blk_drain(bjob->blk); >>> - if (bjdrv->drain) { >>> - bjdrv->drain(bjob); >>> + for (l = bjob->nodes; l; l = l->next) { >>> + BdrvChild *c = l->data; >>> + bdrv_drained_begin(c->bs); >>> + } >>> + for (l = bjob->nodes; l; l = l->next) { >>> + BdrvChild *c = l->data; >>> + bdrv_drained_end(c->bs); >>> } >>> } >>> >>> >> >> Seems much nicer to me. What becomes of the ref/unref pairs? >> >> I guess not needed anymore?, since job cleanup necessarily happens in >> the main loop context now and we don't have a backup_complete function >> anymore ...? > > What pairs do you mean? blk_ref / blk_unref in the backup and mirror specific drain paths. > >> >> In the cases where auto_finalize=true, do we have any guarantee that the >> completion callbacks cannot be scheduled while we are here? >> > > Hmm, not simple for me to assume.. Is it a problem? And is it about this patch? >