qemu: process: Refresh -blockdev based blockjobs on reconnect to qemu

Refresh the state of the jobs and process any events that might have
happened while libvirt was not running.

The job state processing requires some care to figure out if a job
needs to be bumped.

For any invalid job try doing our best to cancel it.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/qemu/qemu_blockjob.c

@@ -253,6 +253,111 @@ qemuBlockJobIsRunning(qemuBlockJobDataPtr job)
 }
 
 
+/* returns 1 for a job we didn't reconnect to */
+static int
+qemuBlockJobRefreshJobsFindInactive(const void *payload,
+                                    const void *name ATTRIBUTE_UNUSED,
+                                    const void *data ATTRIBUTE_UNUSED)
+{
+    const qemuBlockJobData *job = payload;
+
+    return !job->reconnected;
+}
+
+
+int
+qemuBlockJobRefreshJobs(virQEMUDriverPtr driver,
+                        virDomainObjPtr vm)
+{
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    qemuMonitorJobInfoPtr *jobinfo = NULL;
+    size_t njobinfo = 0;
+    qemuBlockJobDataPtr job = NULL;
+    int newstate;
+    size_t i;
+    int ret = -1;
+    int rc;
+
+    qemuDomainObjEnterMonitor(driver, vm);
+
+    rc = qemuMonitorGetJobInfo(priv->mon, &jobinfo, &njobinfo);
+
+    if (qemuDomainObjExitMonitor(driver, vm) < 0 || rc < 0)
+        goto cleanup;
+
+    for (i = 0; i < njobinfo; i++) {
+        if (!(job = virHashLookup(priv->blockjobs, jobinfo[i]->id))) {
+            VIR_DEBUG("ignoring untracked job '%s'", jobinfo[i]->id);
+            continue;
+        }
+
+        /* try cancelling invalid jobs - this works only if the job is not
+         * concluded. In such case it will fail. We'll leave such job linger
+         * in qemu and just forget about it in libvirt because there's not much
+         * we coud do besides killing the VM */
+        if (job->invalidData) {
+            qemuDomainObjEnterMonitor(driver, vm);
+
+            rc = qemuMonitorJobCancel(priv->mon, job->name, true);
+            if (rc == -1 && jobinfo[i]->status == QEMU_MONITOR_JOB_STATUS_CONCLUDED)
+                VIR_WARN("can't cancel job '%s' with invalid data", job->name);
+
+            if (qemuDomainObjExitMonitor(driver, vm) < 0)
+                goto cleanup;
+
+            if (rc < 0)
+                qemuBlockJobUnregister(job, vm);
+            continue;
+        }
+
+        if ((newstate = qemuBlockjobConvertMonitorStatus(jobinfo[i]->status)) < 0)
+            continue;
+
+        if (newstate != job->state) {
+            if ((job->state == QEMU_BLOCKJOB_STATE_FAILED ||
+                 job->state == QEMU_BLOCKJOB_STATE_COMPLETED)) {
+                /* preserve the old state but allow the job to be bumped to
+                 * execute the finishing steps */
+                job->newstate = job->state;
+            } else if (newstate == QEMU_BLOCKJOB_STATE_CONCLUDED) {
+                if (VIR_STRDUP(job->errmsg, jobinfo[i]->error) < 0)
+                    goto cleanup;
+
+                if (job->errmsg)
+                    job->newstate = QEMU_BLOCKJOB_STATE_FAILED;
+                else
+                    job->newstate = QEMU_BLOCKJOB_STATE_COMPLETED;
+            } else if (newstate == QEMU_BLOCKJOB_STATE_READY) {
+                /* Apply _READY state only if it was not applied before */
+                if (job->state == QEMU_BLOCKJOB_STATE_NEW ||
+                    job->state == QEMU_BLOCKJOB_STATE_RUNNING)
+                    job->newstate = newstate;
+            }
+            /* don't update the job otherwise */
+        }
+
+        job->reconnected = true;
+
+        if (job->newstate != -1)
+            qemuBlockJobUpdate(vm, job, QEMU_ASYNC_JOB_NONE);
+    }
+
+    /* remove data for job which qemu didn't report (the algorithm is
+     * inefficient, but the possibility of such jobs is very low */
+    while ((job = virHashSearch(priv->blockjobs, qemuBlockJobRefreshJobsFindInactive, NULL, NULL)))
+        qemuBlockJobUnregister(job, vm);
+
+    ret = 0;
+
+ cleanup:
+    for (i = 0; i < njobinfo; i++)
+        qemuMonitorJobInfoFree(jobinfo[i]);
+    VIR_FREE(jobinfo);
+
+    return ret;
+}
+
+
 /**
  * qemuBlockJobEmitEvents:
  *

src/qemu/qemu_blockjob.h

@@ -84,6 +84,7 @@ struct _qemuBlockJobData {
     int newstate; /* qemuBlockjobState, subset of events emitted by qemu */
 
     bool invalidData; /* the job data (except name) is not valid */
+    bool reconnected; /* internal field for tracking whether job is live after reconnect to qemu */
 };
 
 int
@@ -122,6 +123,10 @@ void
 qemuBlockJobStartupFinalize(virDomainObjPtr vm,
                             qemuBlockJobDataPtr job);
 
+int
+qemuBlockJobRefreshJobs(virQEMUDriverPtr driver,
+                        virDomainObjPtr vm);
+
 int qemuBlockJobUpdate(virDomainObjPtr vm,
                        qemuBlockJobDataPtr job,
                        int asyncJob);

src/qemu/qemu_process.c

@@ -7953,7 +7953,12 @@ static int
 qemuProcessRefreshBlockjobs(virQEMUDriverPtr driver,
                             virDomainObjPtr vm)
 {
-    return qemuProcessRefreshLegacyBlockjobs(driver, vm);
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+
+    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV))
+        return qemuBlockJobRefreshJobs(driver, vm);
+    else
+        return qemuProcessRefreshLegacyBlockjobs(driver, vm);
 }