From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56008) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fxxbF-0007uJ-Tk for qemu-devel@nongnu.org; Thu, 06 Sep 2018 12:57:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fxxbE-0005o0-Vd for qemu-devel@nongnu.org; Thu, 06 Sep 2018 12:57:45 -0400 Date: Thu, 6 Sep 2018 12:57:20 -0400 From: Jeff Cody Message-ID: <20180906165720.GD22117@localhost.localdomain> References: <20180906130225.5118-1-jsnow@redhat.com> <20180906130225.5118-7-jsnow@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180906130225.5118-7-jsnow@redhat.com> Subject: Re: [Qemu-devel] [PATCH v5 06/16] block/mirror: conservative mirror_exit refactor List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org, Kevin Wolf , Markus Armbruster , Eric Blake , "Dr. David Alan Gilbert" , Max Reitz On Thu, Sep 06, 2018 at 09:02:15AM -0400, John Snow wrote: > For purposes of minimum code movement, refactor the mirror_exit > callback to use the post-finalization callbacks in a trivial way. > > Signed-off-by: John Snow > --- > block/mirror.c | 39 ++++++++++++++++++++++++++++----------- > 1 file changed, 28 insertions(+), 11 deletions(-) > > diff --git a/block/mirror.c b/block/mirror.c > index bd3e908710..a92b4702c5 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -79,6 +79,7 @@ typedef struct MirrorBlockJob { > int max_iov; > bool initial_zeroing_ongoing; > int in_active_write_counter; > + bool prepared; > } MirrorBlockJob; > > typedef struct MirrorBDSOpaque { > @@ -607,7 +608,7 @@ static void mirror_wait_for_all_io(MirrorBlockJob *s) > } > } > > -static void mirror_exit(Job *job) > +static int mirror_exit_common(Job *job) > { > MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); > BlockJob *bjob = &s->common; > @@ -617,7 +618,13 @@ static void mirror_exit(Job *job) > BlockDriverState *target_bs = blk_bs(s->target); > BlockDriverState *mirror_top_bs = s->mirror_top_bs; > Error *local_err = NULL; > - int ret = job->ret; > + bool abort = job->ret < 0; > + int ret = 0; > + > + if (s->prepared) { > + return 0; > + } > + s->prepared = true; > > bdrv_release_dirty_bitmap(src, s->dirty_bitmap); > > @@ -642,7 +649,7 @@ static void mirror_exit(Job *job) > * required before it could become a backing file of target_bs. */ > bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL, > &error_abort); > - if (ret == 0 && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { > + if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { > BlockDriverState *backing = s->is_none_mode ? src : s->base; > if (backing_bs(target_bs) != backing) { > bdrv_set_backing_hd(target_bs, backing, &local_err); > @@ -658,11 +665,8 @@ static void mirror_exit(Job *job) > aio_context_acquire(replace_aio_context); > } > > - if (s->should_complete && ret == 0) { > - BlockDriverState *to_replace = src; > - if (s->to_replace) { > - to_replace = s->to_replace; > - } > + if (s->should_complete && !abort) { > + BlockDriverState *to_replace = s->to_replace ?: src; > > if (bdrv_get_flags(target_bs) != bdrv_get_flags(to_replace)) { > bdrv_reopen(target_bs, bdrv_get_flags(to_replace), NULL); > @@ -711,7 +715,18 @@ static void mirror_exit(Job *job) > bdrv_unref(mirror_top_bs); > bdrv_unref(src); > > - job->ret = ret; > + return ret; > +} > + > +static int mirror_prepare(Job *job) > +{ > + return mirror_exit_common(job); > +} > + > +static void mirror_abort(Job *job) > +{ > + int ret = mirror_exit_common(job); > + assert(ret == 0); Not something to hold the series up, but in case a v6 is called for due to other changes: I think it may be worth a comment in mirror_exit_common() that if abort is true, and we don't return success, QEMU will hit an assert. Mainly to prevent someone from including a call with a potential error return in the abort path in the future. Reviewed-by: Jeff Cody > } > > static void mirror_throttle(MirrorBlockJob *s) > @@ -1132,7 +1147,8 @@ static const BlockJobDriver mirror_job_driver = { > .user_resume = block_job_user_resume, > .drain = block_job_drain, > .run = mirror_run, > - .exit = mirror_exit, > + .prepare = mirror_prepare, > + .abort = mirror_abort, > .pause = mirror_pause, > .complete = mirror_complete, > }, > @@ -1149,7 +1165,8 @@ static const BlockJobDriver commit_active_job_driver = { > .user_resume = block_job_user_resume, > .drain = block_job_drain, > .run = mirror_run, > - .exit = mirror_exit, > + .prepare = mirror_prepare, > + .abort = mirror_abort, > .pause = mirror_pause, > .complete = mirror_complete, > }, > -- > 2.14.4 >