blockjobs: add NULL state
Add a new state that specifically demarcates when we begin to permanently demolish a job after it has performed all work. This makes the transition explicit in the STM table and highlights conditions under which a job may be demolished. Alongside this state, add a new helper command "block_job_decommission", which transitions to the NULL state and puts down our implicit reference. This separates instances in the code for "block_job_unref" which merely undo a matching "block_job_ref" with instances intended to initiate the full destruction of the object. This decommission action also sets a number of fields to make sure that block internals or external users that are holding a reference to a job to see when it "finishes" are convinced that the job object is "done." This is necessary, for instance, to do a block_job_cancel_sync on a created object which will not make any progress. Now, all jobs must go through block_job_decommission prior to being freed, giving us start-to-finish state machine coverage for jobs. Transitions: Created -> Null: Early failure event before the job is started Concluded -> Null: Standard transition. Verbs: None. This should not ever be visible to the monitor. +---------+ |UNDEFINED| +--+------+ | +--v----+ +---------+CREATED+------------------+ | +--+----+ | | | | | +--v----+ +------+ | +---------+RUNNING<----->PAUSED| | | +--+-+--+ +------+ | | | | | | | +------------------+ | | | | | | +--v--+ +-------+ | | +---------+READY<------->STANDBY| | | | +--+--+ +-------+ | | | | | | +--v-----+ +--v------+ | | |ABORTING+--->CONCLUDED<-------------+ | +--------+ +--+------+ | | | +--v-+ | |NULL<---------------------+ +----+ Signed-off-by: John Snow <jsnow@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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blockjob.c
50
blockjob.c
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@ -44,24 +44,25 @@ static QemuMutex block_job_mutex;
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/* BlockJob State Transition Table */
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bool BlockJobSTT[BLOCK_JOB_STATUS__MAX][BLOCK_JOB_STATUS__MAX] = {
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/* U, C, R, P, Y, S, X, E */
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/* U: */ [BLOCK_JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0},
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/* C: */ [BLOCK_JOB_STATUS_CREATED] = {0, 0, 1, 0, 0, 0, 1, 0},
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/* R: */ [BLOCK_JOB_STATUS_RUNNING] = {0, 0, 0, 1, 1, 0, 1, 1},
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/* P: */ [BLOCK_JOB_STATUS_PAUSED] = {0, 0, 1, 0, 0, 0, 0, 0},
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/* Y: */ [BLOCK_JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 1},
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/* S: */ [BLOCK_JOB_STATUS_STANDBY] = {0, 0, 0, 0, 1, 0, 0, 0},
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/* X: */ [BLOCK_JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 0, 1},
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/* E: */ [BLOCK_JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0},
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/* U, C, R, P, Y, S, X, E, N */
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/* U: */ [BLOCK_JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0, 0},
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/* C: */ [BLOCK_JOB_STATUS_CREATED] = {0, 0, 1, 0, 0, 0, 1, 0, 1},
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/* R: */ [BLOCK_JOB_STATUS_RUNNING] = {0, 0, 0, 1, 1, 0, 1, 1, 0},
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/* P: */ [BLOCK_JOB_STATUS_PAUSED] = {0, 0, 1, 0, 0, 0, 0, 0, 0},
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/* Y: */ [BLOCK_JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 1, 0},
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/* S: */ [BLOCK_JOB_STATUS_STANDBY] = {0, 0, 0, 0, 1, 0, 0, 0, 0},
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/* X: */ [BLOCK_JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 0, 1, 0},
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/* E: */ [BLOCK_JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 1},
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/* N: */ [BLOCK_JOB_STATUS_NULL] = {0, 0, 0, 0, 0, 0, 0, 0, 0},
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};
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bool BlockJobVerbTable[BLOCK_JOB_VERB__MAX][BLOCK_JOB_STATUS__MAX] = {
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/* U, C, R, P, Y, S, X, E */
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[BLOCK_JOB_VERB_CANCEL] = {0, 1, 1, 1, 1, 1, 0, 0},
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[BLOCK_JOB_VERB_PAUSE] = {0, 1, 1, 1, 1, 1, 0, 0},
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[BLOCK_JOB_VERB_RESUME] = {0, 1, 1, 1, 1, 1, 0, 0},
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[BLOCK_JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1, 1, 0, 0},
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[BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0},
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/* U, C, R, P, Y, S, X, E, N */
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[BLOCK_JOB_VERB_CANCEL] = {0, 1, 1, 1, 1, 1, 0, 0, 0},
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[BLOCK_JOB_VERB_PAUSE] = {0, 1, 1, 1, 1, 1, 0, 0, 0},
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[BLOCK_JOB_VERB_RESUME] = {0, 1, 1, 1, 1, 1, 0, 0, 0},
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[BLOCK_JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1, 1, 0, 0, 0},
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[BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0, 0},
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};
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static void block_job_state_transition(BlockJob *job, BlockJobStatus s1)
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@ -225,6 +226,7 @@ static void block_job_detach_aio_context(void *opaque);
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void block_job_unref(BlockJob *job)
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{
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if (--job->refcnt == 0) {
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assert(job->status == BLOCK_JOB_STATUS_NULL);
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BlockDriverState *bs = blk_bs(job->blk);
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QLIST_REMOVE(job, job_list);
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bs->job = NULL;
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@ -378,6 +380,17 @@ void block_job_start(BlockJob *job)
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bdrv_coroutine_enter(blk_bs(job->blk), job->co);
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}
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static void block_job_decommission(BlockJob *job)
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{
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assert(job);
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job->completed = true;
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job->busy = false;
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job->paused = false;
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job->deferred_to_main_loop = true;
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block_job_state_transition(job, BLOCK_JOB_STATUS_NULL);
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block_job_unref(job);
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}
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static void block_job_conclude(BlockJob *job)
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{
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block_job_state_transition(job, BLOCK_JOB_STATUS_CONCLUDED);
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@ -424,7 +437,7 @@ static void block_job_completed_single(BlockJob *job)
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QLIST_REMOVE(job, txn_list);
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block_job_txn_unref(job->txn);
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block_job_conclude(job);
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block_job_unref(job);
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block_job_decommission(job);
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}
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static void block_job_cancel_async(BlockJob *job)
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@ -817,7 +830,7 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
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block_job_set_speed(job, speed, &local_err);
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if (local_err) {
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block_job_unref(job);
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block_job_early_fail(job);
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error_propagate(errp, local_err);
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return NULL;
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}
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@ -851,7 +864,8 @@ void block_job_pause_all(void)
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void block_job_early_fail(BlockJob *job)
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{
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block_job_unref(job);
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assert(job->status == BLOCK_JOB_STATUS_CREATED);
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block_job_decommission(job);
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}
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void block_job_completed(BlockJob *job, int ret)
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@ -1006,11 +1006,14 @@
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# @concluded: The job has finished all work. If manual was set to true, the job
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# will remain in the query list until it is dismissed.
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#
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# @null: The job is in the process of being dismantled. This state should not
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# ever be visible externally.
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#
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# Since: 2.12
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##
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{ 'enum': 'BlockJobStatus',
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'data': ['undefined', 'created', 'running', 'paused', 'ready', 'standby',
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'aborting', 'concluded' ] }
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'aborting', 'concluded', 'null' ] }
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##
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# @BlockJobInfo:
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