From 430c298d6bf9a7c8b90ad30bc2cd445e5cd6dd50 Mon Sep 17 00:00:00 2001 From: John Snow Date: Thu, 6 Sep 2018 09:02:15 -0400 Subject: block/mirror: conservative mirror_exit refactor RH-Author: John Snow Message-id: <20180925223431.24791-16-jsnow@redhat.com> Patchwork-id: 82270 O-Subject: [RHEL8/rhel qemu-kvm PATCH 15/25] block/mirror: conservative mirr Bugzilla: 1632939 RH-Acked-by: Jeffrey Cody RH-Acked-by: Max Reitz RH-Acked-by: Kevin Wolf 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 Message-id: 20180906130225.5118-7-jsnow@redhat.com Reviewed-by: Jeff Cody Reviewed-by: Max Reitz [mreitz: Added comment for the mirror_exit() function] Signed-off-by: Max Reitz (cherry picked from commit 737efc1eda23b904fbe0e66b37715fb0e5c3e58b) Signed-off-by: John Snow --- block/mirror.c | 44 +++++++++++++++++++++++++++++++++----------- 1 file changed, 33 insertions(+), 11 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 19b57b8..7efba77 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 +608,12 @@ static void mirror_wait_for_all_io(MirrorBlockJob *s) } } -static void mirror_exit(Job *job) +/** + * mirror_exit_common: handle both abort() and prepare() cases. + * for .prepare, returns 0 on success and -errno on failure. + * for .abort cases, denoted by abort = true, MUST return 0. + */ +static int mirror_exit_common(Job *job) { MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); BlockJob *bjob = &s->common; @@ -617,7 +623,13 @@ 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 +654,7 @@ 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 +670,8 @@ 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 +720,18 @@ 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); } static void mirror_throttle(MirrorBlockJob *s) @@ -1132,7 +1152,8 @@ 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 +1170,8 @@ 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, }, -- 1.8.3.1