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xemu/job.c
Hanna Reitz a640fa0e38 mirror: Do not clear .cancelled 
Clearing .cancelled before leaving the main loop when the job has been
soft-cancelled is no longer necessary since job_is_cancelled() only
returns true for jobs that have been force-cancelled.

Therefore, this only makes a differences in places that call
job_cancel_requested().  In block/mirror.c, this is done only before
.cancelled was cleared.

In job.c, there are two callers:
- job_completed_txn_abort() asserts that .cancelled is true, so keeping
  it true will not affect this place.

- job_complete() refuses to let a job complete that has .cancelled set.
  It is correct to refuse to let the user invoke job-complete on mirror
  jobs that have already been soft-cancelled.

With this change, there are no places that reset .cancelled to false and
so we can be sure that .force_cancel can only be true if .cancelled is
true as well.  Assert this in job_is_cancelled().

Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006151940.214590-13-hreitz@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
2021-10-07 10:42:50 +02:00

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/*
* Background jobs (long-running operations)
*
* Copyright (c) 2011 IBM Corp.
* Copyright (c) 2012, 2018 Red Hat, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/job.h"
#include "qemu/id.h"
#include "qemu/main-loop.h"
#include "block/aio-wait.h"
#include "trace/trace-root.h"
#include "qapi/qapi-events-job.h"
static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs);
/* Job State Transition Table */
bool JobSTT[JOB_STATUS__MAX][JOB_STATUS__MAX] = {
/* U, C, R, P, Y, S, W, D, X, E, N */
/* U: */ [JOB_STATUS_UNDEFINED] = {0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},
/* C: */ [JOB_STATUS_CREATED] = {0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1},
/* R: */ [JOB_STATUS_RUNNING] = {0, 0, 0, 1, 1, 0, 1, 0, 1, 0, 0},
/* P: */ [JOB_STATUS_PAUSED] = {0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},
/* Y: */ [JOB_STATUS_READY] = {0, 0, 0, 0, 0, 1, 1, 0, 1, 0, 0},
/* S: */ [JOB_STATUS_STANDBY] = {0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},
/* W: */ [JOB_STATUS_WAITING] = {0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0},
/* D: */ [JOB_STATUS_PENDING] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
/* X: */ [JOB_STATUS_ABORTING] = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0},
/* E: */ [JOB_STATUS_CONCLUDED] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},
/* N: */ [JOB_STATUS_NULL] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0},
};
bool JobVerbTable[JOB_VERB__MAX][JOB_STATUS__MAX] = {
/* U, C, R, P, Y, S, W, D, X, E, N */
[JOB_VERB_CANCEL] = {0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0},
[JOB_VERB_PAUSE] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
[JOB_VERB_RESUME] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
[JOB_VERB_SET_SPEED] = {0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0},
[JOB_VERB_COMPLETE] = {0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0},
[JOB_VERB_FINALIZE] = {0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},
[JOB_VERB_DISMISS] = {0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0},
};
/* Transactional group of jobs */
struct JobTxn {
/* Is this txn being cancelled? */
bool aborting;
/* List of jobs */
QLIST_HEAD(, Job) jobs;
/* Reference count */
int refcnt;
};
/* Right now, this mutex is only needed to synchronize accesses to job->busy
* and job->sleep_timer, such as concurrent calls to job_do_yield and
* job_enter. */
static QemuMutex job_mutex;
static void job_lock(void)
{
qemu_mutex_lock(&job_mutex);
}
static void job_unlock(void)
{
qemu_mutex_unlock(&job_mutex);
}
static void __attribute__((__constructor__)) job_init(void)
{
qemu_mutex_init(&job_mutex);
}
JobTxn *job_txn_new(void)
{
JobTxn *txn = g_new0(JobTxn, 1);
QLIST_INIT(&txn->jobs);
txn->refcnt = 1;
return txn;
}
static void job_txn_ref(JobTxn *txn)
{
txn->refcnt++;
}
void job_txn_unref(JobTxn *txn)
{
if (txn && --txn->refcnt == 0) {
g_free(txn);
}
}
void job_txn_add_job(JobTxn *txn, Job *job)
{
if (!txn) {
return;
}
assert(!job->txn);
job->txn = txn;
QLIST_INSERT_HEAD(&txn->jobs, job, txn_list);
job_txn_ref(txn);
}
static void job_txn_del_job(Job *job)
{
if (job->txn) {
QLIST_REMOVE(job, txn_list);
job_txn_unref(job->txn);
job->txn = NULL;
}
}
static int job_txn_apply(Job *job, int fn(Job *))
{
AioContext *inner_ctx;
Job *other_job, *next;
JobTxn *txn = job->txn;
int rc = 0;
/*
* Similar to job_completed_txn_abort, we take each job's lock before
* applying fn, but since we assume that outer_ctx is held by the caller,
* we need to release it here to avoid holding the lock twice - which would
* break AIO_WAIT_WHILE from within fn.
*/
job_ref(job);
aio_context_release(job->aio_context);
QLIST_FOREACH_SAFE(other_job, &txn->jobs, txn_list, next) {
inner_ctx = other_job->aio_context;
aio_context_acquire(inner_ctx);
rc = fn(other_job);
aio_context_release(inner_ctx);
if (rc) {
break;
}
}
/*
* Note that job->aio_context might have been changed by calling fn, so we
* can't use a local variable to cache it.
*/
aio_context_acquire(job->aio_context);
job_unref(job);
return rc;
}
bool job_is_internal(Job *job)
{
return (job->id == NULL);
}
static void job_state_transition(Job *job, JobStatus s1)
{
JobStatus s0 = job->status;
assert(s1 >= 0 && s1 < JOB_STATUS__MAX);
trace_job_state_transition(job, job->ret,
JobSTT[s0][s1] ? "allowed" : "disallowed",
JobStatus_str(s0), JobStatus_str(s1));
assert(JobSTT[s0][s1]);
job->status = s1;
if (!job_is_internal(job) && s1 != s0) {
qapi_event_send_job_status_change(job->id, job->status);
}
}
int job_apply_verb(Job *job, JobVerb verb, Error **errp)
{
JobStatus s0 = job->status;
assert(verb >= 0 && verb < JOB_VERB__MAX);
trace_job_apply_verb(job, JobStatus_str(s0), JobVerb_str(verb),
JobVerbTable[verb][s0] ? "allowed" : "prohibited");
if (JobVerbTable[verb][s0]) {
return 0;
}
error_setg(errp, "Job '%s' in state '%s' cannot accept command verb '%s'",
job->id, JobStatus_str(s0), JobVerb_str(verb));
return -EPERM;
}
JobType job_type(const Job *job)
{
return job->driver->job_type;
}
const char *job_type_str(const Job *job)
{
return JobType_str(job_type(job));
}
bool job_is_cancelled(Job *job)
{
/* force_cancel may be true only if cancelled is true, too */
assert(job->cancelled || !job->force_cancel);
return job->force_cancel;
}
bool job_cancel_requested(Job *job)
{
return job->cancelled;
}
bool job_is_ready(Job *job)
{
switch (job->status) {
case JOB_STATUS_UNDEFINED:
case JOB_STATUS_CREATED:
case JOB_STATUS_RUNNING:
case JOB_STATUS_PAUSED:
case JOB_STATUS_WAITING:
case JOB_STATUS_PENDING:
case JOB_STATUS_ABORTING:
case JOB_STATUS_CONCLUDED:
case JOB_STATUS_NULL:
return false;
case JOB_STATUS_READY:
case JOB_STATUS_STANDBY:
return true;
default:
g_assert_not_reached();
}
return false;
}
bool job_is_completed(Job *job)
{
switch (job->status) {
case JOB_STATUS_UNDEFINED:
case JOB_STATUS_CREATED:
case JOB_STATUS_RUNNING:
case JOB_STATUS_PAUSED:
case JOB_STATUS_READY:
case JOB_STATUS_STANDBY:
return false;
case JOB_STATUS_WAITING:
case JOB_STATUS_PENDING:
case JOB_STATUS_ABORTING:
case JOB_STATUS_CONCLUDED:
case JOB_STATUS_NULL:
return true;
default:
g_assert_not_reached();
}
return false;
}
static bool job_started(Job *job)
{
return job->co;
}
static bool job_should_pause(Job *job)
{
return job->pause_count > 0;
}
Job *job_next(Job *job)
{
if (!job) {
return QLIST_FIRST(&jobs);
}
return QLIST_NEXT(job, job_list);
}
Job *job_get(const char *id)
{
Job *job;
QLIST_FOREACH(job, &jobs, job_list) {
if (job->id && !strcmp(id, job->id)) {
return job;
}
}
return NULL;
}
static void job_sleep_timer_cb(void *opaque)
{
Job *job = opaque;
job_enter(job);
}
void *job_create(const char *job_id, const JobDriver *driver, JobTxn *txn,
AioContext *ctx, int flags, BlockCompletionFunc *cb,
void *opaque, Error **errp)
{
Job *job;
if (job_id) {
if (flags & JOB_INTERNAL) {
error_setg(errp, "Cannot specify job ID for internal job");
return NULL;
}
if (!id_wellformed(job_id)) {
error_setg(errp, "Invalid job ID '%s'", job_id);
return NULL;
}
if (job_get(job_id)) {
error_setg(errp, "Job ID '%s' already in use", job_id);
return NULL;
}
} else if (!(flags & JOB_INTERNAL)) {
error_setg(errp, "An explicit job ID is required");
return NULL;
}
job = g_malloc0(driver->instance_size);
job->driver = driver;
job->id = g_strdup(job_id);
job->refcnt = 1;
job->aio_context = ctx;
job->busy = false;
job->paused = true;
job->pause_count = 1;
job->auto_finalize = !(flags & JOB_MANUAL_FINALIZE);
job->auto_dismiss = !(flags & JOB_MANUAL_DISMISS);
job->cb = cb;
job->opaque = opaque;
progress_init(&job->progress);
notifier_list_init(&job->on_finalize_cancelled);
notifier_list_init(&job->on_finalize_completed);
notifier_list_init(&job->on_pending);
notifier_list_init(&job->on_ready);
job_state_transition(job, JOB_STATUS_CREATED);
aio_timer_init(qemu_get_aio_context(), &job->sleep_timer,
QEMU_CLOCK_REALTIME, SCALE_NS,
job_sleep_timer_cb, job);
QLIST_INSERT_HEAD(&jobs, job, job_list);
/* Single jobs are modeled as single-job transactions for sake of
* consolidating the job management logic */
if (!txn) {
txn = job_txn_new();
job_txn_add_job(txn, job);
job_txn_unref(txn);
} else {
job_txn_add_job(txn, job);
}
return job;
}
void job_ref(Job *job)
{
++job->refcnt;
}
void job_unref(Job *job)
{
if (--job->refcnt == 0) {
assert(job->status == JOB_STATUS_NULL);
assert(!timer_pending(&job->sleep_timer));
assert(!job->txn);
if (job->driver->free) {
job->driver->free(job);
}
QLIST_REMOVE(job, job_list);
progress_destroy(&job->progress);
error_free(job->err);
g_free(job->id);
g_free(job);
}
}
void job_progress_update(Job *job, uint64_t done)
{
progress_work_done(&job->progress, done);
}
void job_progress_set_remaining(Job *job, uint64_t remaining)
{
progress_set_remaining(&job->progress, remaining);
}
void job_progress_increase_remaining(Job *job, uint64_t delta)
{
progress_increase_remaining(&job->progress, delta);
}
void job_event_cancelled(Job *job)
{
notifier_list_notify(&job->on_finalize_cancelled, job);
}
void job_event_completed(Job *job)
{
notifier_list_notify(&job->on_finalize_completed, job);
}
static void job_event_pending(Job *job)
{
notifier_list_notify(&job->on_pending, job);
}
static void job_event_ready(Job *job)
{
notifier_list_notify(&job->on_ready, job);
}
static void job_event_idle(Job *job)
{
notifier_list_notify(&job->on_idle, job);
}
void job_enter_cond(Job *job, bool(*fn)(Job *job))
{
if (!job_started(job)) {
return;
}
if (job->deferred_to_main_loop) {
return;
}
job_lock();
if (job->busy) {
job_unlock();
return;
}
if (fn && !fn(job)) {
job_unlock();
return;
}
assert(!job->deferred_to_main_loop);
timer_del(&job->sleep_timer);
job->busy = true;
job_unlock();
aio_co_enter(job->aio_context, job->co);
}
void job_enter(Job *job)
{
job_enter_cond(job, NULL);
}
/* Yield, and schedule a timer to reenter the coroutine after @ns nanoseconds.
* Reentering the job coroutine with job_enter() before the timer has expired
* is allowed and cancels the timer.
*
* If @ns is (uint64_t) -1, no timer is scheduled and job_enter() must be
* called explicitly. */
static void coroutine_fn job_do_yield(Job *job, uint64_t ns)
{
job_lock();
if (ns != -1) {
timer_mod(&job->sleep_timer, ns);
}
job->busy = false;
job_event_idle(job);
job_unlock();
qemu_coroutine_yield();
/* Set by job_enter_cond() before re-entering the coroutine. */
assert(job->busy);
}
void coroutine_fn job_pause_point(Job *job)
{
assert(job && job_started(job));
if (!job_should_pause(job)) {
return;
}
if (job_is_cancelled(job)) {
return;
}
if (job->driver->pause) {
job->driver->pause(job);
}
if (job_should_pause(job) && !job_is_cancelled(job)) {
JobStatus status = job->status;
job_state_transition(job, status == JOB_STATUS_READY
? JOB_STATUS_STANDBY
: JOB_STATUS_PAUSED);
job->paused = true;
job_do_yield(job, -1);
job->paused = false;
job_state_transition(job, status);
}
if (job->driver->resume) {
job->driver->resume(job);
}
}
void job_yield(Job *job)
{
assert(job->busy);
/* Check cancellation *before* setting busy = false, too! */
if (job_is_cancelled(job)) {
return;
}
if (!job_should_pause(job)) {
job_do_yield(job, -1);
}
job_pause_point(job);
}
void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
{
assert(job->busy);
/* Check cancellation *before* setting busy = false, too! */
if (job_is_cancelled(job)) {
return;
}
if (!job_should_pause(job)) {
job_do_yield(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns);
}
job_pause_point(job);
}
/* Assumes the block_job_mutex is held */
static bool job_timer_not_pending(Job *job)
{
return !timer_pending(&job->sleep_timer);
}
void job_pause(Job *job)
{
job->pause_count++;
if (!job->paused) {
job_enter(job);
}
}
void job_resume(Job *job)
{
assert(job->pause_count > 0);
job->pause_count--;
if (job->pause_count) {
return;
}
/* kick only if no timer is pending */
job_enter_cond(job, job_timer_not_pending);
}
void job_user_pause(Job *job, Error **errp)
{
if (job_apply_verb(job, JOB_VERB_PAUSE, errp)) {
return;
}
if (job->user_paused) {
error_setg(errp, "Job is already paused");
return;
}
job->user_paused = true;
job_pause(job);
}
bool job_user_paused(Job *job)
{
return job->user_paused;
}
void job_user_resume(Job *job, Error **errp)
{
assert(job);
if (!job->user_paused || job->pause_count <= 0) {
error_setg(errp, "Can't resume a job that was not paused");
return;
}
if (job_apply_verb(job, JOB_VERB_RESUME, errp)) {
return;
}
if (job->driver->user_resume) {
job->driver->user_resume(job);
}
job->user_paused = false;
job_resume(job);
}
static void job_do_dismiss(Job *job)
{
assert(job);
job->busy = false;
job->paused = false;
job->deferred_to_main_loop = true;
job_txn_del_job(job);
job_state_transition(job, JOB_STATUS_NULL);
job_unref(job);
}
void job_dismiss(Job **jobptr, Error **errp)
{
Job *job = *jobptr;
/* similarly to _complete, this is QMP-interface only. */
assert(job->id);
if (job_apply_verb(job, JOB_VERB_DISMISS, errp)) {
return;
}
job_do_dismiss(job);
*jobptr = NULL;
}
void job_early_fail(Job *job)
{
assert(job->status == JOB_STATUS_CREATED);
job_do_dismiss(job);
}
static void job_conclude(Job *job)
{
job_state_transition(job, JOB_STATUS_CONCLUDED);
if (job->auto_dismiss || !job_started(job)) {
job_do_dismiss(job);
}
}
static void job_update_rc(Job *job)
{
if (!job->ret && job_is_cancelled(job)) {
job->ret = -ECANCELED;
}
if (job->ret) {
if (!job->err) {
error_setg(&job->err, "%s", strerror(-job->ret));
}
job_state_transition(job, JOB_STATUS_ABORTING);
}
}
static void job_commit(Job *job)
{
assert(!job->ret);
if (job->driver->commit) {
job->driver->commit(job);
}
}
static void job_abort(Job *job)
{
assert(job->ret);
if (job->driver->abort) {
job->driver->abort(job);
}
}
static void job_clean(Job *job)
{
if (job->driver->clean) {
job->driver->clean(job);
}
}
static int job_finalize_single(Job *job)
{
assert(job_is_completed(job));
/* Ensure abort is called for late-transactional failures */
job_update_rc(job);
if (!job->ret) {
job_commit(job);
} else {
job_abort(job);
}
job_clean(job);
if (job->cb) {
job->cb(job->opaque, job->ret);
}
/* Emit events only if we actually started */
if (job_started(job)) {
if (job_is_cancelled(job)) {
job_event_cancelled(job);
} else {
job_event_completed(job);
}
}
job_txn_del_job(job);
job_conclude(job);
return 0;
}
static void job_cancel_async(Job *job, bool force)
{
if (job->driver->cancel) {
force = job->driver->cancel(job, force);
} else {
/* No .cancel() means the job will behave as if force-cancelled */
force = true;
}
if (job->user_paused) {
/* Do not call job_enter here, the caller will handle it. */
if (job->driver->user_resume) {
job->driver->user_resume(job);
}
job->user_paused = false;
assert(job->pause_count > 0);
job->pause_count--;
}
/*
* Ignore soft cancel requests after the job is already done
* (We will still invoke job->driver->cancel() above, but if the
* job driver supports soft cancelling and the job is done, that
* should be a no-op, too. We still call it so it can override
* @force.)
*/
if (force || !job->deferred_to_main_loop) {
job->cancelled = true;
/* To prevent 'force == false' overriding a previous 'force == true' */
job->force_cancel |= force;
}
}
static void job_completed_txn_abort(Job *job)
{
AioContext *ctx;
JobTxn *txn = job->txn;
Job *other_job;
if (txn->aborting) {
/*
* We are cancelled by another job, which will handle everything.
*/
return;
}
txn->aborting = true;
job_txn_ref(txn);
/*
* We can only hold the single job's AioContext lock while calling
* job_finalize_single() because the finalization callbacks can involve
* calls of AIO_WAIT_WHILE(), which could deadlock otherwise.
* Note that the job's AioContext may change when it is finalized.
*/
job_ref(job);
aio_context_release(job->aio_context);
/* Other jobs are effectively cancelled by us, set the status for
* them; this job, however, may or may not be cancelled, depending
* on the caller, so leave it. */
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
if (other_job != job) {
ctx = other_job->aio_context;
aio_context_acquire(ctx);
/*
* This is a transaction: If one job failed, no result will matter.
* Therefore, pass force=true to terminate all other jobs as quickly
* as possible.
*/
job_cancel_async(other_job, true);
aio_context_release(ctx);
}
}
while (!QLIST_EMPTY(&txn->jobs)) {
other_job = QLIST_FIRST(&txn->jobs);
/*
* The job's AioContext may change, so store it in @ctx so we
* release the same context that we have acquired before.
*/
ctx = other_job->aio_context;
aio_context_acquire(ctx);
if (!job_is_completed(other_job)) {
assert(job_cancel_requested(other_job));
job_finish_sync(other_job, NULL, NULL);
}
job_finalize_single(other_job);
aio_context_release(ctx);
}
/*
* Use job_ref()/job_unref() so we can read the AioContext here
* even if the job went away during job_finalize_single().
*/
aio_context_acquire(job->aio_context);
job_unref(job);
job_txn_unref(txn);
}
static int job_prepare(Job *job)
{
if (job->ret == 0 && job->driver->prepare) {
job->ret = job->driver->prepare(job);
job_update_rc(job);
}
return job->ret;
}
static int job_needs_finalize(Job *job)
{
return !job->auto_finalize;
}
static void job_do_finalize(Job *job)
{
int rc;
assert(job && job->txn);
/* prepare the transaction to complete */
rc = job_txn_apply(job, job_prepare);
if (rc) {
job_completed_txn_abort(job);
} else {
job_txn_apply(job, job_finalize_single);
}
}
void job_finalize(Job *job, Error **errp)
{
assert(job && job->id);
if (job_apply_verb(job, JOB_VERB_FINALIZE, errp)) {
return;
}
job_do_finalize(job);
}
static int job_transition_to_pending(Job *job)
{
job_state_transition(job, JOB_STATUS_PENDING);
if (!job->auto_finalize) {
job_event_pending(job);
}
return 0;
}
void job_transition_to_ready(Job *job)
{
job_state_transition(job, JOB_STATUS_READY);
job_event_ready(job);
}
static void job_completed_txn_success(Job *job)
{
JobTxn *txn = job->txn;
Job *other_job;
job_state_transition(job, JOB_STATUS_WAITING);
/*
* Successful completion, see if there are other running jobs in this
* txn.
*/
QLIST_FOREACH(other_job, &txn->jobs, txn_list) {
if (!job_is_completed(other_job)) {
return;
}
assert(other_job->ret == 0);
}
job_txn_apply(job, job_transition_to_pending);
/* If no jobs need manual finalization, automatically do so */
if (job_txn_apply(job, job_needs_finalize) == 0) {
job_do_finalize(job);
}
}
static void job_completed(Job *job)
{
assert(job && job->txn && !job_is_completed(job));
job_update_rc(job);
trace_job_completed(job, job->ret);
if (job->ret) {
job_completed_txn_abort(job);
} else {
job_completed_txn_success(job);
}
}
/** Useful only as a type shim for aio_bh_schedule_oneshot. */
static void job_exit(void *opaque)
{
Job *job = (Job *)opaque;
AioContext *ctx;
job_ref(job);
aio_context_acquire(job->aio_context);
/* This is a lie, we're not quiescent, but still doing the completion
* callbacks. However, completion callbacks tend to involve operations that
* drain block nodes, and if .drained_poll still returned true, we would
* deadlock. */
job->busy = false;
job_event_idle(job);
job_completed(job);
/*
* Note that calling job_completed can move the job to a different
* aio_context, so we cannot cache from above. job_txn_apply takes care of
* acquiring the new lock, and we ref/unref to avoid job_completed freeing
* the job underneath us.
*/
ctx = job->aio_context;
job_unref(job);
aio_context_release(ctx);
}
/**
* All jobs must allow a pause point before entering their job proper. This
* ensures that jobs can be paused prior to being started, then resumed later.
*/
static void coroutine_fn job_co_entry(void *opaque)
{
Job *job = opaque;
assert(job && job->driver && job->driver->run);
job_pause_point(job);
job->ret = job->driver->run(job, &job->err);
job->deferred_to_main_loop = true;
job->busy = true;
aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
}
void job_start(Job *job)
{
assert(job && !job_started(job) && job->paused &&
job->driver && job->driver->run);
job->co = qemu_coroutine_create(job_co_entry, job);
job->pause_count--;
job->busy = true;
job->paused = false;
job_state_transition(job, JOB_STATUS_RUNNING);
aio_co_enter(job->aio_context, job->co);
}
void job_cancel(Job *job, bool force)
{
if (job->status == JOB_STATUS_CONCLUDED) {
job_do_dismiss(job);
return;
}
job_cancel_async(job, force);
if (!job_started(job)) {
job_completed(job);
} else if (job->deferred_to_main_loop) {
/*
* job_cancel_async() ignores soft-cancel requests for jobs
* that are already done (i.e. deferred to the main loop). We
* have to check again whether the job is really cancelled.
* (job_cancel_requested() and job_is_cancelled() are equivalent
* here, because job_cancel_async() will make soft-cancel
* requests no-ops when deferred_to_main_loop is true. We
* choose to call job_is_cancelled() to show that we invoke
* job_completed_txn_abort() only for force-cancelled jobs.)
*/
if (job_is_cancelled(job)) {
job_completed_txn_abort(job);
}
} else {
job_enter(job);
}
}
void job_user_cancel(Job *job, bool force, Error **errp)
{
if (job_apply_verb(job, JOB_VERB_CANCEL, errp)) {
return;
}
job_cancel(job, force);
}
/* A wrapper around job_cancel() taking an Error ** parameter so it may be
* used with job_finish_sync() without the need for (rather nasty) function
* pointer casts there. */
static void job_cancel_err(Job *job, Error **errp)
{
job_cancel(job, false);
}
/**
* Same as job_cancel_err(), but force-cancel.
*/
static void job_force_cancel_err(Job *job, Error **errp)
{
job_cancel(job, true);
}
int job_cancel_sync(Job *job, bool force)
{
if (force) {
return job_finish_sync(job, &job_force_cancel_err, NULL);
} else {
return job_finish_sync(job, &job_cancel_err, NULL);
}
}
void job_cancel_sync_all(void)
{
Job *job;
AioContext *aio_context;
while ((job = job_next(NULL))) {
aio_context = job->aio_context;
aio_context_acquire(aio_context);
job_cancel_sync(job, true);
aio_context_release(aio_context);
}
}
int job_complete_sync(Job *job, Error **errp)
{
return job_finish_sync(job, job_complete, errp);
}
void job_complete(Job *job, Error **errp)
{
/* Should not be reachable via external interface for internal jobs */
assert(job->id);
if (job_apply_verb(job, JOB_VERB_COMPLETE, errp)) {
return;
}
if (job_cancel_requested(job) || !job->driver->complete) {
error_setg(errp, "The active block job '%s' cannot be completed",
job->id);
return;
}
job->driver->complete(job, errp);
}
int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
{
Error *local_err = NULL;
int ret;
job_ref(job);
if (finish) {
finish(job, &local_err);
}
if (local_err) {
error_propagate(errp, local_err);
job_unref(job);
return -EBUSY;
}
AIO_WAIT_WHILE(job->aio_context,
(job_enter(job), !job_is_completed(job)));
ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret;
job_unref(job);
return ret;
}
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