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blockjob: Wake up BDS when job becomes idle
In the context of draining a BDS, the .drained_poll callback of block jobs is called. If this returns true (i.e. there is still some activity pending), the drain operation may call aio_poll() with blocking=true to wait for completion. As soon as the pending activity is completed and the job finally arrives in a quiescent state (i.e. its coroutine either yields with busy=false or terminates), the block job must notify the aio_poll() loop to wake up, otherwise we get a deadlock if both are running in different threads. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
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parent
d1756c780b
commit
34dc97b9a0
18
blockjob.c
18
blockjob.c
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@ -221,6 +221,22 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
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return 0;
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}
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void block_job_wakeup_all_bdrv(BlockJob *job)
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{
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GSList *l;
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for (l = job->nodes; l; l = l->next) {
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BdrvChild *c = l->data;
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bdrv_wakeup(c->bs);
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}
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}
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static void block_job_on_idle(Notifier *n, void *opaque)
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{
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BlockJob *job = opaque;
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block_job_wakeup_all_bdrv(job);
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}
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bool block_job_is_internal(BlockJob *job)
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{
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return (job->job.id == NULL);
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@ -416,6 +432,7 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
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job->finalize_completed_notifier.notify = block_job_event_completed;
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job->pending_notifier.notify = block_job_event_pending;
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job->ready_notifier.notify = block_job_event_ready;
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job->idle_notifier.notify = block_job_on_idle;
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notifier_list_add(&job->job.on_finalize_cancelled,
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&job->finalize_cancelled_notifier);
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@ -423,6 +440,7 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
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&job->finalize_completed_notifier);
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notifier_list_add(&job->job.on_pending, &job->pending_notifier);
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notifier_list_add(&job->job.on_ready, &job->ready_notifier);
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notifier_list_add(&job->job.on_idle, &job->idle_notifier);
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error_setg(&job->blocker, "block device is in use by block job: %s",
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job_type_str(&job->job));
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@ -70,6 +70,9 @@ typedef struct BlockJob {
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/** Called when the job transitions to READY */
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Notifier ready_notifier;
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/** Called when the job coroutine yields or terminates */
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Notifier idle_notifier;
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/** BlockDriverStates that are involved in this block job */
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GSList *nodes;
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} BlockJob;
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@ -118,6 +121,16 @@ int block_job_add_bdrv(BlockJob *job, const char *name, BlockDriverState *bs,
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*/
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void block_job_remove_all_bdrv(BlockJob *job);
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/**
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* block_job_wakeup_all_bdrv:
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* @job: The block job
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*
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* Calls bdrv_wakeup() for all BlockDriverStates that have been added to the
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* job. This function is to be called whenever child_job_drained_poll() would
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* go from true to false to notify waiting drain requests.
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*/
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void block_job_wakeup_all_bdrv(BlockJob *job);
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/**
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* block_job_set_speed:
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* @job: The job to set the speed for.
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@ -156,6 +156,9 @@ typedef struct Job {
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/** Notifiers called when the job transitions to READY */
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NotifierList on_ready;
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/** Notifiers called when the job coroutine yields or terminates */
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NotifierList on_idle;
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/** Element of the list of jobs */
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QLIST_ENTRY(Job) job_list;
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7
job.c
7
job.c
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@ -402,6 +402,11 @@ static void job_event_ready(Job *job)
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notifier_list_notify(&job->on_ready, job);
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}
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static void job_event_idle(Job *job)
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{
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notifier_list_notify(&job->on_idle, job);
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}
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void job_enter_cond(Job *job, bool(*fn)(Job *job))
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{
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if (!job_started(job)) {
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@ -447,6 +452,7 @@ static void coroutine_fn job_do_yield(Job *job, uint64_t ns)
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timer_mod(&job->sleep_timer, ns);
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}
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job->busy = false;
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job_event_idle(job);
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job_unlock();
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qemu_coroutine_yield();
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@ -865,6 +871,7 @@ static void coroutine_fn job_co_entry(void *opaque)
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assert(job && job->driver && job->driver->run);
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job_pause_point(job);
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job->ret = job->driver->run(job, &job->err);
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job_event_idle(job);
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job->deferred_to_main_loop = true;
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aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
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}
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