X-Git-Url: https://git.proxmox.com/?a=blobdiff_plain;f=job.c;h=04409b40aab3545798414bda1a872b5fb8490965;hb=50276a79aa15713decfede5cab183fc371e3e57d;hp=fd10b1d26712a3663972dc2889443f1837c223b1;hpb=b15de82867975e0b4acf644b5ee36d84904b6612;p=mirror_qemu.git

diff --git a/job.c b/job.c
index fd10b1d267..04409b40aa 100644
--- a/job.c
+++ b/job.c
@@ -24,12 +24,13 @@
  */
 
 #include "qemu/osdep.h"
-#include "qemu-common.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-root.h"
+#include "qapi/qapi-events-job.h"
 
 static QLIST_HEAD(, Job) jobs = QLIST_HEAD_INITIALIZER(jobs);
 
@@ -60,6 +61,19 @@ bool JobVerbTable[JOB_VERB__MAX][JOB_STATUS__MAX] = {
     [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. */
@@ -80,22 +94,86 @@ static void __attribute__((__constructor__)) job_init(void)
     qemu_mutex_init(&job_mutex);
 }
 
-/* TODO Make static once the whole state machine is in job.c */
-void job_state_transition(Job *job, JobStatus s1)
+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(JobTxn *txn, int fn(Job *))
+{
+    Job *job, *next;
+    int rc = 0;
+
+    QLIST_FOREACH_SAFE(job, &txn->jobs, txn_list, next) {
+        rc = fn(job);
+        if (rc) {
+            break;
+        }
+    }
+    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, /* TODO re-enable: job->ret */ 0,
+    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);
+    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]) {
@@ -121,12 +199,56 @@ bool job_is_cancelled(Job *job)
     return job->cancelled;
 }
 
-bool job_started(Job *job)
+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;
 }
 
-bool job_should_pause(Job *job)
+static bool job_should_pause(Job *job)
 {
     return job->pause_count > 0;
 }
@@ -159,12 +281,17 @@ static void job_sleep_timer_cb(void *opaque)
     job_enter(job);
 }
 
-void *job_create(const char *job_id, const JobDriver *driver, AioContext *ctx,
-                 Error **errp)
+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;
@@ -173,6 +300,9 @@ void *job_create(const char *job_id, const JobDriver *driver, AioContext *ctx,
             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);
@@ -183,6 +313,15 @@ void *job_create(const char *job_id, const JobDriver *driver, AioContext *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;
+
+    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,
@@ -191,6 +330,16 @@ void *job_create(const char *job_id, const JobDriver *driver, AioContext *ctx,
 
     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;
 }
 
@@ -204,6 +353,7 @@ 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);
@@ -211,11 +361,52 @@ void job_unref(Job *job)
 
         QLIST_REMOVE(job, job_list);
 
+        error_free(job->err);
         g_free(job->id);
         g_free(job);
     }
 }
 
+void job_progress_update(Job *job, uint64_t done)
+{
+    job->progress_current += done;
+}
+
+void job_progress_set_remaining(Job *job, uint64_t remaining)
+{
+    job->progress_total = job->progress_current + remaining;
+}
+
+void job_progress_increase_remaining(Job *job, uint64_t delta)
+{
+    job->progress_total += 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)) {
@@ -240,7 +431,7 @@ void job_enter_cond(Job *job, bool(*fn)(Job *job))
     timer_del(&job->sleep_timer);
     job->busy = true;
     job_unlock();
-    aio_co_wake(job->co);
+    aio_co_enter(job->aio_context, job->co);
 }
 
 void job_enter(Job *job)
@@ -249,18 +440,19 @@ void job_enter(Job *job)
 }
 
 /* Yield, and schedule a timer to reenter the coroutine after @ns nanoseconds.
- * Reentering the job coroutine with block_job_enter() before the timer has
- * expired is allowed and cancels the timer.
+ * 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 block_job_enter() must be
+ * If @ns is (uint64_t) -1, no timer is scheduled and job_enter() must be
  * called explicitly. */
-void coroutine_fn job_do_yield(Job *job, uint64_t ns)
+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();
 
@@ -299,7 +491,7 @@ void coroutine_fn job_pause_point(Job *job)
     }
 }
 
-void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
+void job_yield(Job *job)
 {
     assert(job->busy);
 
@@ -309,36 +501,26 @@ void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
     }
 
     if (!job_should_pause(job)) {
-        job_do_yield(job, qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + ns);
+        job_do_yield(job, -1);
     }
 
     job_pause_point(job);
 }
 
-/**
- * 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)
+void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
 {
-    Job *job = opaque;
+    assert(job->busy);
 
-    assert(job && job->driver && job->driver->start);
-    job_pause_point(job);
-    job->driver->start(job);
-}
+    /* 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);
+    }
 
-void job_start(Job *job)
-{
-    assert(job && !job_started(job) && job->paused &&
-           job->driver && job->driver->start);
-    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);
+    job_pause_point(job);
 }
 
 /* Assumes the block_job_mutex is held */
@@ -399,34 +581,409 @@ void job_user_resume(Job *job, Error **errp)
     job_resume(job);
 }
 
+static void job_do_dismiss(Job *job)
+{
+    assert(job);
+    job->busy = false;
+    job->paused = false;
+    job->deferred_to_main_loop = true;
 
-typedef struct {
-    Job *job;
-    JobDeferToMainLoopFn *fn;
-    void *opaque;
-} JobDeferToMainLoopData;
+    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_defer_to_main_loop_bh(void *opaque)
+static void job_clean(Job *job)
 {
-    JobDeferToMainLoopData *data = opaque;
-    Job *job = data->job;
-    AioContext *aio_context = job->aio_context;
+    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);
+    }
 
-    aio_context_acquire(aio_context);
-    data->fn(data->job, data->opaque);
-    aio_context_release(aio_context);
+    /* 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);
+        }
+    }
 
-    g_free(data);
+    job_txn_del_job(job);
+    job_conclude(job);
+    return 0;
+}
+
+static void job_cancel_async(Job *job, bool force)
+{
+    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--;
+    }
+    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 *outer_ctx = job->aio_context;
+    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. */
+    aio_context_release(outer_ctx);
+
+    /* 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);
+            job_cancel_async(other_job, false);
+            aio_context_release(ctx);
+        }
+    }
+    while (!QLIST_EMPTY(&txn->jobs)) {
+        other_job = QLIST_FIRST(&txn->jobs);
+        ctx = other_job->aio_context;
+        aio_context_acquire(ctx);
+        if (!job_is_completed(other_job)) {
+            assert(job_is_cancelled(other_job));
+            job_finish_sync(other_job, NULL, NULL);
+        }
+        job_finalize_single(other_job);
+        aio_context_release(ctx);
+    }
+
+    aio_context_acquire(outer_ctx);
+
+    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;
 }
 
-void job_defer_to_main_loop(Job *job, JobDeferToMainLoopFn *fn, void *opaque)
+static int job_needs_finalize(Job *job)
 {
-    JobDeferToMainLoopData *data = g_malloc(sizeof(*data));
-    data->job = job;
-    data->fn = fn;
-    data->opaque = opaque;
+    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->txn, job_prepare);
+    if (rc) {
+        job_completed_txn_abort(job);
+    } else {
+        job_txn_apply(job->txn, 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(txn, job_transition_to_pending);
+
+    /* If no jobs need manual finalization, automatically do so */
+    if (job_txn_apply(txn, 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->aio_context;
+
+    aio_context_acquire(ctx);
+
+    /* 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);
+
+    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_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);
+}
+
+int job_cancel_sync(Job *job)
+{
+    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);
+        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->pause_count || job_is_cancelled(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)));
 
-    aio_bh_schedule_oneshot(qemu_get_aio_context(),
-                            job_defer_to_main_loop_bh, data);
+    ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret;
+    job_unref(job);
+    return ret;
 }