qemu: domain: Store blockjob data in the status XML

We need to store the block job state in the status XML so that we can
properly recover any data when reconnecting after startup and also in
the end to be able to do any transition of the backing chain that
happened while libvirt was not connected to the monitor.

First step is to note the name, type, state and corresponding disk into
the status XML.

We also need to make sure that a broken blockjob does not make libvirt
lose the VM, thus many of the errors just mark the job as invalid.
Later on we'll cancel all invalid jobs.
Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/qemu/qemu_domain.c

@@ -32,6 +32,7 @@
 #include "qemu_migration_params.h"
 #include "qemu_security.h"
 #include "qemu_extdevice.h"
+#include "qemu_blockjob.h"
 #include "viralloc.h"
 #include "virlog.h"
 #include "virerror.h"
@@ -2305,17 +2306,57 @@ qemuDomainObjPrivateXMLFormatAutomaticPlacement(virBufferPtr buf,
 }
 
 
+static int
+qemuDomainObjPrivateXMLFormatBlockjobIterator(void *payload,
+                                              const void *name ATTRIBUTE_UNUSED,
+                                              void *data)
+{
+    VIR_AUTOCLEAN(virBuffer) attrBuf = VIR_BUFFER_INITIALIZER;
+    VIR_AUTOCLEAN(virBuffer) childBuf = VIR_BUFFER_INITIALIZER;
+    qemuBlockJobDataPtr job = payload;
+    virBufferPtr buf = data;
+    const char *state = qemuBlockjobStateTypeToString(job->state);
+    const char *newstate = NULL;
+
+    if (job->newstate != -1)
+        newstate = qemuBlockjobStateTypeToString(job->newstate);
+
+    virBufferSetChildIndent(&childBuf, buf);
+
+    virBufferEscapeString(&attrBuf, " name='%s'", job->name);
+    virBufferEscapeString(&attrBuf, " type='%s'", qemuBlockjobTypeToString(job->type));
+    virBufferEscapeString(&attrBuf, " state='%s'", state);
+    virBufferEscapeString(&attrBuf, " newstate='%s'", newstate);
+    virBufferEscapeString(&childBuf, "<errmsg>%s</errmsg>", job->errmsg);
+
+    if (job->disk)
+        virBufferEscapeString(&childBuf, "<disk dst='%s'/>\n", job->disk->dst);
+
+    return virXMLFormatElement(buf, "blockjob", &attrBuf, &childBuf);
+}
+
+
 static int
 qemuDomainObjPrivateXMLFormatBlockjobs(virBufferPtr buf,
                                        virDomainObjPtr vm)
 {
-    virBuffer attrBuf = VIR_BUFFER_INITIALIZER;
+    qemuDomainObjPrivatePtr priv = vm->privateData;
+    VIR_AUTOCLEAN(virBuffer) attrBuf = VIR_BUFFER_INITIALIZER;
+    VIR_AUTOCLEAN(virBuffer) childBuf = VIR_BUFFER_INITIALIZER;
     bool bj = qemuDomainHasBlockjob(vm, false);
 
     virBufferAsprintf(&attrBuf, " active='%s'",
                       virTristateBoolTypeToString(virTristateBoolFromBool(bj)));
 
-    return virXMLFormatElement(buf, "blockjobs", &attrBuf, NULL);
+    virBufferSetChildIndent(&childBuf, buf);
+
+    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV) &&
+        virHashForEach(priv->blockjobs,
+                       qemuDomainObjPrivateXMLFormatBlockjobIterator,
+                       &childBuf) < 0)
+        return -1;
+
+    return virXMLFormatElement(buf, "blockjobs", &attrBuf, &childBuf);
 }
 
 
@@ -2655,16 +2696,90 @@ qemuDomainObjPrivateXMLParseAutomaticPlacement(xmlXPathContextPtr ctxt,
 
 
 static int
-qemuDomainObjPrivateXMLParseBlockjobs(qemuDomainObjPrivatePtr priv,
+qemuDomainObjPrivateXMLParseBlockjobData(virDomainObjPtr vm,
+                                         xmlNodePtr node,
+                                         xmlXPathContextPtr ctxt)
+{
+    VIR_XPATH_NODE_AUTORESTORE(ctxt);
+    virDomainDiskDefPtr disk = NULL;
+    VIR_AUTOUNREF(qemuBlockJobDataPtr) job = NULL;
+    VIR_AUTOFREE(char *) name = NULL;
+    VIR_AUTOFREE(char *) typestr = NULL;
+    int type;
+    VIR_AUTOFREE(char *) statestr = NULL;
+    int state = QEMU_BLOCKJOB_STATE_FAILED;
+    VIR_AUTOFREE(char *) diskdst = NULL;
+    VIR_AUTOFREE(char *) newstatestr = NULL;
+    int newstate = -1;
+    bool invalidData = false;
+
+    ctxt->node = node;
+
+    if (!(name = virXPathString("string(./@name)", ctxt))) {
+        VIR_WARN("malformed block job data for vm '%s'", vm->def->name);
+        return 0;
+    }
+
+    /* if the job name is known we need to register such a job so that we can
+     * clean it up */
+    if (!(typestr = virXPathString("string(./@type)", ctxt)) ||
+        (type = qemuBlockjobTypeFromString(typestr)) < 0) {
+        type = QEMU_BLOCKJOB_TYPE_NONE;
+        invalidData = true;
+    }
+
+    if (!(job = qemuBlockJobDataNew(type, name)))
+        return -1;
+
+    if (!(statestr = virXPathString("string(./@state)", ctxt)) ||
+        (state = qemuBlockjobStateTypeFromString(statestr)) < 0)
+        invalidData = true;
+
+    if ((newstatestr = virXPathString("string(./@newstate)", ctxt)) &&
+        (newstate = qemuBlockjobStateTypeFromString(newstatestr)) < 0)
+        invalidData = true;
+
+    if ((diskdst = virXPathString("string(./disk/@dst)", ctxt)) &&
+        !(disk = virDomainDiskByName(vm->def, diskdst, false)))
+        invalidData = true;
+
+    job->state = state;
+    job->newstate = newstate;
+    job->errmsg = virXPathString("string(./errmsg)", ctxt);
+    job->invalidData = invalidData;
+
+    if (qemuBlockJobRegister(job, vm, disk) < 0)
+        return -1;
+
+    return 0;
+}
+
+
+static int
+qemuDomainObjPrivateXMLParseBlockjobs(virDomainObjPtr vm,
+                                      qemuDomainObjPrivatePtr priv,
                                       xmlXPathContextPtr ctxt)
 {
+    VIR_AUTOFREE(xmlNodePtr *) nodes = NULL;
+    ssize_t nnodes = 0;
     VIR_AUTOFREE(char *) active = NULL;
     int tmp;
+    size_t i;
 
     if ((active = virXPathString("string(./blockjobs/@active)", ctxt)) &&
         (tmp = virTristateBoolTypeFromString(active)) > 0)
         priv->reconnectBlockjobs = tmp;
 
+    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV)) {
+        if ((nnodes = virXPathNodeSet("./blockjobs/blockjob", ctxt, &nodes)) < 0)
+            return -1;
+
+        for (i = 0; i < nnodes; i++) {
+            if (qemuDomainObjPrivateXMLParseBlockjobData(vm, nodes[i], ctxt) < 0)
+                return -1;
+        }
+    }
+
     return 0;
 }
 
@@ -3022,7 +3137,7 @@ qemuDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt,
 
     qemuDomainObjPrivateXMLParsePR(ctxt, &priv->prDaemonRunning);
 
-    if (qemuDomainObjPrivateXMLParseBlockjobs(priv, ctxt) < 0)
+    if (qemuDomainObjPrivateXMLParseBlockjobs(vm, priv, ctxt) < 0)
         goto error;
 
     qemuDomainStorageIdReset(priv);