Am 26.09.2022 um 11:32 hat Emanuele Giuseppe Esposito geschrieben:
> iostatus is the only field (together with .job) that needs
> protection using the job mutex.
>
> It is set in the main loop (GLOBAL_STATE functions) but read
> in I/O code (block_job_error_action).
>
> In order to protect it, change block_job_iostatus_set_err
> to block_job_iostatus_set_err_locked(), always called under
> job lock.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eespo...@redhat.com>
> Reviewed-by: Kevin Wolf <kw...@redhat.com>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
> ---
> block/mirror.c | 7 +++++--
> blockjob.c | 5 +++--
> 2 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/block/mirror.c b/block/mirror.c
> index c6bf7f40ce..7e32ee1d31 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -893,7 +893,7 @@ static int coroutine_fn mirror_run(Job *job, Error **errp)
> MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
> BlockDriverState *bs = s->mirror_top_bs->backing->bs;
> BlockDriverState *target_bs = blk_bs(s->target);
> - bool need_drain = true;
> + bool need_drain = true, iostatus;
iostatus isn't really a bool, it's BlockDeviceIoStatus.
> int64_t length;
> int64_t target_length;
> BlockDriverInfo bdi;
> @@ -1016,8 +1016,11 @@ static int coroutine_fn mirror_run(Job *job, Error
> **errp)
> * We do so every BLKOCK_JOB_SLICE_TIME nanoseconds, or when there is
> * an error, or when the source is clean, whichever comes first. */
> delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns;
> + WITH_JOB_LOCK_GUARD() {
> + iostatus = s->common.iostatus;
> + }
> if (delta < BLOCK_JOB_SLICE_TIME &&
> - s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
> + iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
Your code actually happens to work because the one value that you
compare it against is BLOCK_DEVICE_IO_STATUS_OK, which is 0, so it maps
to false and everything else to true, but... it's still not right. :-)
> if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
> (cnt == 0 && s->in_flight > 0)) {
> trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight);
Kevin
