From 3925cd3bc7bdc82b7889fd97e7cad52dfee5e8a6 Mon Sep 17 00:00:00 2001 From: John Snow Date: Sat, 10 Mar 2018 03:27:35 -0500 Subject: [PATCH] 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 Signed-off-by: Kevin Wolf --- blockjob.c | 50 ++++++++++++++++++++++++++++---------------- qapi/block-core.json | 5 ++++- 2 files changed, 36 insertions(+), 19 deletions(-) diff --git a/blockjob.c b/blockjob.c index 3f730967b3..2ef48075b0 100644 --- a/blockjob.c +++ b/blockjob.c @@ -44,24 +44,25 @@ static QemuMutex block_job_mutex; /* BlockJob State Transition Table */ bool BlockJobSTT[BLOCK_JOB_STATUS__MAX][BLOCK_JOB_STATUS__MAX] = { - /* U, C, R, P, Y, S, X, E */ - /* U: */ [BLOCK_JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0}, - /* C: */ [BLOCK_JOB_STATUS_CREATED] = {0, 0, 1, 0, 0, 0, 1, 0}, - /* R: */ [BLOCK_JOB_STATUS_RUNNING] = {0, 0, 0, 1, 1, 0, 1, 1}, - /* P: */ [BLOCK_JOB_STATUS_PAUSED] = {0, 0, 1, 0, 0, 0, 0, 0}, - /* Y: */ [BLOCK_JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 1}, - /* S: */ [BLOCK_JOB_STATUS_STANDBY] = {0, 0, 0, 0, 1, 0, 0, 0}, - /* X: */ [BLOCK_JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 0, 1}, - /* E: */ [BLOCK_JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0}, + /* U, C, R, P, Y, S, X, E, N */ + /* U: */ [BLOCK_JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0, 0}, + /* C: */ [BLOCK_JOB_STATUS_CREATED] = {0, 0, 1, 0, 0, 0, 1, 0, 1}, + /* R: */ [BLOCK_JOB_STATUS_RUNNING] = {0, 0, 0, 1, 1, 0, 1, 1, 0}, + /* P: */ [BLOCK_JOB_STATUS_PAUSED] = {0, 0, 1, 0, 0, 0, 0, 0, 0}, + /* Y: */ [BLOCK_JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 1, 0}, + /* S: */ [BLOCK_JOB_STATUS_STANDBY] = {0, 0, 0, 0, 1, 0, 0, 0, 0}, + /* X: */ [BLOCK_JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 0, 1, 0}, + /* E: */ [BLOCK_JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 1}, + /* N: */ [BLOCK_JOB_STATUS_NULL] = {0, 0, 0, 0, 0, 0, 0, 0, 0}, }; bool BlockJobVerbTable[BLOCK_JOB_VERB__MAX][BLOCK_JOB_STATUS__MAX] = { - /* U, C, R, P, Y, S, X, E */ - [BLOCK_JOB_VERB_CANCEL] = {0, 1, 1, 1, 1, 1, 0, 0}, - [BLOCK_JOB_VERB_PAUSE] = {0, 1, 1, 1, 1, 1, 0, 0}, - [BLOCK_JOB_VERB_RESUME] = {0, 1, 1, 1, 1, 1, 0, 0}, - [BLOCK_JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1, 1, 0, 0}, - [BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0}, + /* U, C, R, P, Y, S, X, E, N */ + [BLOCK_JOB_VERB_CANCEL] = {0, 1, 1, 1, 1, 1, 0, 0, 0}, + [BLOCK_JOB_VERB_PAUSE] = {0, 1, 1, 1, 1, 1, 0, 0, 0}, + [BLOCK_JOB_VERB_RESUME] = {0, 1, 1, 1, 1, 1, 0, 0, 0}, + [BLOCK_JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1, 1, 0, 0, 0}, + [BLOCK_JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 0, 0, 0, 0}, }; static void block_job_state_transition(BlockJob *job, BlockJobStatus s1) @@ -225,6 +226,7 @@ static void block_job_detach_aio_context(void *opaque); void block_job_unref(BlockJob *job) { if (--job->refcnt == 0) { + assert(job->status == BLOCK_JOB_STATUS_NULL); BlockDriverState *bs = blk_bs(job->blk); QLIST_REMOVE(job, job_list); bs->job = NULL; @@ -378,6 +380,17 @@ void block_job_start(BlockJob *job) bdrv_coroutine_enter(blk_bs(job->blk), job->co); } +static void block_job_decommission(BlockJob *job) +{ + assert(job); + job->completed = true; + job->busy = false; + job->paused = false; + job->deferred_to_main_loop = true; + block_job_state_transition(job, BLOCK_JOB_STATUS_NULL); + block_job_unref(job); +} + static void block_job_conclude(BlockJob *job) { block_job_state_transition(job, BLOCK_JOB_STATUS_CONCLUDED); @@ -424,7 +437,7 @@ static void block_job_completed_single(BlockJob *job) QLIST_REMOVE(job, txn_list); block_job_txn_unref(job->txn); block_job_conclude(job); - block_job_unref(job); + block_job_decommission(job); } static void block_job_cancel_async(BlockJob *job) @@ -817,7 +830,7 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver, block_job_set_speed(job, speed, &local_err); if (local_err) { - block_job_unref(job); + block_job_early_fail(job); error_propagate(errp, local_err); return NULL; } @@ -851,7 +864,8 @@ void block_job_pause_all(void) void block_job_early_fail(BlockJob *job) { - block_job_unref(job); + assert(job->status == BLOCK_JOB_STATUS_CREATED); + block_job_decommission(job); } void block_job_completed(BlockJob *job, int ret) diff --git a/qapi/block-core.json b/qapi/block-core.json index 7a9d7ad742..ef18abe09a 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -1006,11 +1006,14 @@ # @concluded: The job has finished all work. If manual was set to true, the job # will remain in the query list until it is dismissed. # +# @null: The job is in the process of being dismantled. This state should not +# ever be visible externally. +# # Since: 2.12 ## { 'enum': 'BlockJobStatus', 'data': ['undefined', 'created', 'running', 'paused', 'ready', 'standby', - 'aborting', 'concluded' ] } + 'aborting', 'concluded', 'null' ] } ## # @BlockJobInfo: