From 565ac01f8d35236844dd0257a185f81425cd4b6a Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Thu, 16 Jun 2016 17:56:28 +0100 Subject: [PATCH] mirror: follow AioContext change gracefully 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 --- block/mirror.c | 43 +++++++++++++++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 8 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 075384a9cf..a04ed9c7a4 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -331,6 +331,8 @@ 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)) { @@ -582,6 +584,8 @@ 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)) { @@ -613,6 +617,8 @@ 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 @@ -795,18 +801,39 @@ 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); + + blk_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, - .complete = mirror_complete, + .instance_size = sizeof(MirrorBlockJob), + .job_type = BLOCK_JOB_TYPE_MIRROR, + .set_speed = mirror_set_speed, + .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, - .complete = mirror_complete, + .instance_size = sizeof(MirrorBlockJob), + .job_type = BLOCK_JOB_TYPE_COMMIT, + .set_speed = mirror_set_speed, + .complete = mirror_complete, + .pause = mirror_pause, + .attached_aio_context = mirror_attached_aio_context, }; static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, -- GitLab