From ab650ce95cce80f6edfa48bbf9e2fb6946eeec11 Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Tue, 21 Jun 2016 13:34:21 +0200 Subject: [PATCH 19/25] mirror: follow AioContext change gracefully RH-Author: Stefan Hajnoczi Message-id: <1466516062-20048-9-git-send-email-stefanha@redhat.com> Patchwork-id: 70725 O-Subject: [RHEV-7.3 qemu-kvm-rhev PATCH 8/9] mirror: follow AioContext change gracefully Bugzilla: 1265179 RH-Acked-by: Jeffrey Cody RH-Acked-by: Fam Zheng RH-Acked-by: Paolo Bonzini Add block_job_pause_point() calls to mark quiescent points and make sure to complete in-flight requests when switching AioContexts. This patch solves undefined behavior in the mirror block job when the BDS AioContext is changed by dataplane. Signed-off-by: Stefan Hajnoczi Signed-off-by: Fam Zheng Reviewed-by: Paolo Bonzini Reviewed-by: Fam Zheng Message-id: 1466096189-6477-8-git-send-email-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi (cherry picked from commit 565ac01f8d35236844dd0257a185f81425cd4b6a) Signed-off-by: Miroslav Rezanina Conflicts: block/mirror.c Context conflict because downstream has .iostatus_reset() callbacks in mirror job driver. s/blk_set_aio_context/bdrv_set_aio_context/ Signed-off-by: Stefan Hajnoczi --- block/mirror.c | 48 +++++++++++++++++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 11 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 039f481..07f95a4 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -329,6 +329,8 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) mirror_wait_for_io(s); } + block_job_pause_point(&s->common); + /* Find the number of consective dirty chunks following the first dirty * one, and wait for in flight requests in them. */ while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) { @@ -578,6 +580,8 @@ static void coroutine_fn mirror_run(void *opaque) if (now - last_pause_ns > SLICE_TIME) { last_pause_ns = now; block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); + } else { + block_job_pause_point(&s->common); } if (block_job_is_cancelled(&s->common)) { @@ -609,6 +613,8 @@ static void coroutine_fn mirror_run(void *opaque) goto immediate_exit; } + block_job_pause_point(&s->common); + cnt = bdrv_get_dirty_count(s->dirty_bitmap); /* s->common.offset contains the number of bytes already processed so * far, cnt is the number of dirty sectors remaining and @@ -789,21 +795,41 @@ static void mirror_complete(BlockJob *job, Error **errp) block_job_enter(&s->common); } +/* There is no matching mirror_resume() because mirror_run() will begin + * iterating again when the job is resumed. + */ +static void coroutine_fn mirror_pause(BlockJob *job) +{ + MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); + + mirror_drain(s); +} + +static void mirror_attached_aio_context(BlockJob *job, AioContext *new_context) +{ + MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); + + bdrv_set_aio_context(s->target, new_context); +} + static const BlockJobDriver mirror_job_driver = { - .instance_size = sizeof(MirrorBlockJob), - .job_type = BLOCK_JOB_TYPE_MIRROR, - .set_speed = mirror_set_speed, - .iostatus_reset= mirror_iostatus_reset, - .complete = mirror_complete, + .instance_size = sizeof(MirrorBlockJob), + .job_type = BLOCK_JOB_TYPE_MIRROR, + .set_speed = mirror_set_speed, + .iostatus_reset = mirror_iostatus_reset, + .complete = mirror_complete, + .pause = mirror_pause, + .attached_aio_context = mirror_attached_aio_context, }; static const BlockJobDriver commit_active_job_driver = { - .instance_size = sizeof(MirrorBlockJob), - .job_type = BLOCK_JOB_TYPE_COMMIT, - .set_speed = mirror_set_speed, - .iostatus_reset - = mirror_iostatus_reset, - .complete = mirror_complete, + .instance_size = sizeof(MirrorBlockJob), + .job_type = BLOCK_JOB_TYPE_COMMIT, + .set_speed = mirror_set_speed, + .iostatus_reset = mirror_iostatus_reset, + .complete = mirror_complete, + .pause = mirror_pause, + .attached_aio_context = mirror_attached_aio_context, }; static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, -- 1.8.3.1