[libvirt] [PATCH v3 RESEND 12/12] qemu_migration: Unlink pre-created storage on error

[Michal Privoznik]

If migratioin fails because of whatever reason and we've
pre-created any disks, we should remove them instead of letting
them lying around. Moreover, we need to save the disks sources
into domain status file in case libvirtd gets restarted.
---
 src/qemu/qemu_domain.c    | 30 ++++++++++++++++++++++++++++--
 src/qemu/qemu_domain.h    |  2 ++
 src/qemu/qemu_migration.c | 13 +++++++++++++
 src/qemu/qemu_process.c   |  8 ++++++++
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 8df2739..66e0d82 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -231,10 +231,15 @@ error:
 
 static void qemuDomainObjPrivateFree(void *data)
 {
+    size_t i;
     qemuDomainObjPrivatePtr priv = data;
 
     virObjectUnref(priv->qemuCaps);
 
+    for (i = 0; i < priv->nnbdDisk; i++)
+        VIR_FREE(priv->nbdDisk[i]);
+    VIR_FREE(priv->nbdDisk);
+
     qemuDomainPCIAddressSetFree(priv->pciaddrs);
     virDomainChrSourceDefFree(priv->monConfig);
     qemuDomainObjFreeJob(priv);
@@ -263,6 +268,7 @@ static int qemuDomainObjPrivateXMLFormat(virBufferPtr buf, void *data)
     qemuDomainObjPrivatePtr priv = data;
     const char *monitorpath;
     enum qemuDomainJob job;
+    size_t i;
 
     /* priv->monitor_chr is set only for qemu */
     if (priv->monConfig) {
@@ -285,7 +291,6 @@ static int qemuDomainObjPrivateXMLFormat(virBufferPtr buf, void *data)
 
 
     if (priv->nvcpupids) {
-        int i;
         virBufferAddLit(buf, "  <vcpus>\n");
         for (i = 0 ; i < priv->nvcpupids ; i++) {
             virBufferAsprintf(buf, "    <vcpu pid='%d'/>\n", priv->vcpupids[i]);
@@ -294,7 +299,6 @@ static int qemuDomainObjPrivateXMLFormat(virBufferPtr buf, void *data)
     }
 
     if (priv->qemuCaps) {
-        int i;
         virBufferAddLit(buf, "  <qemuCaps>\n");
         for (i = 0 ; i < QEMU_CAPS_LAST ; i++) {
             if (virQEMUCapsGet(priv->qemuCaps, i)) {
@@ -328,6 +332,13 @@ static int qemuDomainObjPrivateXMLFormat(virBufferPtr buf, void *data)
     if (priv->fakeReboot)
         virBufferAsprintf(buf, "  <fakereboot/>\n");
 
+    if (priv->nnbdDisk) {
+        virBufferAddLit(buf, "  <nbdDisk>\n");
+        for (i = 0; i < priv->nnbdDisk; i++)
+            virBufferAsprintf(buf, "    <disk src='%s'/>\n", priv->nbdDisk[i]);
+        virBufferAddLit(buf, "  </nbdDisk>\n");
+    }
+
     return 0;
 }
 
@@ -473,6 +484,21 @@ static int qemuDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt, void *data)
 
     priv->fakeReboot = virXPathBoolean("boolean(./fakereboot)", ctxt) == 1;
 
+    n = virXPathNodeSet("./nbdDisk/disk", ctxt, &nodes);
+    if (n < 0)
+        goto error;
+    if (n) {
+        if (VIR_REALLOC_N(priv->nbdDisk, n) < 0) {
+            virReportOOMError();
+            goto error;
+        }
+        priv->nnbdDisk = n;
+
+        for (i = 0; i < n; i++)
+            if (!(priv->nbdDisk[i] = virXMLPropString(nodes[i], "src")))
+                goto error;
+    }
+
     return 0;
 
 error:
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 4e20a49..83a2c1f 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -155,6 +155,8 @@ struct _qemuDomainObjPrivate {
     unsigned long migMaxBandwidth;
     char *origname;
     int nbdPort; /* Port used for migration with NBD */
+    size_t nnbdDisk;
+    char **nbdDisk; /* src of disks we want to transfer via NBD */
 
     virChrdevsPtr devs;
 
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 95b6102..fb4b7ac 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -1565,6 +1565,7 @@ qemuMigrationPreCreateStorage(virQEMUDriverPtr driver,
                               virDomainObjPtr vm,
                               qemuMigrationCookiePtr mig)
 {
+    qemuDomainObjPrivatePtr priv = vm->privateData;
     int ret = -1;
     size_t i = 0;
 
@@ -1611,6 +1612,11 @@ qemuMigrationPreCreateStorage(virQEMUDriverPtr driver,
             goto cleanup;
         }
 
+        if ((VIR_REALLOC_N(priv->nbdDisk, priv->nnbdDisk + 1) < 0) ||
+            !(priv->nbdDisk[priv->nnbdDisk++] = strdup(disk->src))) {
+            virReportOOMError();
+            goto cleanup;
+        }
     }
 
     ret = 0;
@@ -4055,6 +4061,7 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
     qemuDomainObjPrivatePtr priv = vm->privateData;
     virQEMUDriverConfigPtr cfg = virQEMUDriverGetConfig(driver);
     virCapsPtr caps = NULL;
+    size_t i;
 
     VIR_DEBUG("driver=%p, dconn=%p, vm=%p, cookiein=%s, cookieinlen=%d, "
               "cookieout=%p, cookieoutlen=%p, flags=%lx, retcode=%d",
@@ -4208,6 +4215,12 @@ qemuMigrationFinish(virQEMUDriverPtr driver,
                                                  VIR_DOMAIN_EVENT_SUSPENDED,
                                                  VIR_DOMAIN_EVENT_SUSPENDED_PAUSED);
             }
+
+            /* Free disks transferred via NBD so they don't get deleted */
+            for (i = 0; i < priv->nnbdDisk; i++)
+                VIR_FREE(priv->nbdDisk[i]);
+            VIR_FREE(priv->nbdDisk);
+            priv->nnbdDisk = 0;
         }
 
         if (virDomainObjIsActive(vm) &&
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index e6874e2..9fa7004 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4242,6 +4242,14 @@ void qemuProcessStop(virQEMUDriverPtr driver,
         priv->nbdPort = 0;
     }
 
+    for (i = 0; i < priv->nnbdDisk; i++) {
+        VIR_DEBUG("Unlinking %s due to unsuccessful NBD transfer",
+                  priv->nbdDisk[i]);
+        if (unlink(priv->nbdDisk[i]) < 0)
+            virReportSystemError(errno, _("Unable to unlink %s"),
+                                 priv->nbdDisk[i]);
+    }
+
     if (priv->agent) {
         qemuAgentClose(priv->agent);
         priv->agent = NULL;
-- 
1.8.0.2