qemu: cancel drive mirrors when p2p connection breaks

When a connection to the destination host during a p2p migration drops,
we know we will have to cancel the migration; it doesn't make sense to
waste resources by trying to finish the migration. We already do so
after sending "migrate" command to QEMU and we should do it while
waiting for drive mirrors to become ready too.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_migration.c

@@ -1932,7 +1932,8 @@ static int
 qemuMigrationCancelDriveMirror(virQEMUDriverPtr driver,
                                virDomainObjPtr vm,
                                bool check,
-                               qemuDomainAsyncJob asyncJob)
+                               qemuDomainAsyncJob asyncJob,
+                               virConnectPtr dconn)
 {
     virErrorPtr err = NULL;
     int ret = -1;
@@ -1963,6 +1964,13 @@ qemuMigrationCancelDriveMirror(virQEMUDriverPtr driver,
     }
 
     while ((rv = qemuMigrationDriveMirrorCancelled(driver, vm, check)) != 1) {
+        if (check && !failed &&
+            dconn && virConnectIsAlive(dconn) <= 0) {
+            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
+                           _("Lost connection to destination host"));
+            failed = true;
+        }
+
         if (rv < 0) {
             failed = true;
             if (rv == -2)
@@ -2015,7 +2023,8 @@ qemuMigrationDriveMirror(virQEMUDriverPtr driver,
                          unsigned long speed,
                          unsigned int *migrate_flags,
                          size_t nmigrate_disks,
-                         const char **migrate_disks)
+                         const char **migrate_disks,
+                         virConnectPtr dconn)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
     int ret = -1;
@@ -2095,6 +2104,12 @@ qemuMigrationDriveMirror(virQEMUDriverPtr driver,
             goto cleanup;
         }
 
+        if (dconn && virConnectIsAlive(dconn) <= 0) {
+            virReportError(VIR_ERR_OPERATION_FAILED, "%s",
+                           _("Lost connection to destination host"));
+            goto cleanup;
+        }
+
         if (virDomainObjWait(vm) < 0)
             goto cleanup;
     }
@@ -3749,7 +3764,7 @@ qemuMigrationConfirmPhase(virQEMUDriverPtr driver,
 
         /* cancel any outstanding NBD jobs */
         qemuMigrationCancelDriveMirror(driver, vm, false,
-                                       QEMU_ASYNC_JOB_MIGRATION_OUT);
+                                       QEMU_ASYNC_JOB_MIGRATION_OUT, NULL);
 
         virSetError(orig_err);
         virFreeError(orig_err);
@@ -4169,7 +4184,8 @@ qemuMigrationRun(virQEMUDriverPtr driver,
                                          migrate_speed,
                                          &migrate_flags,
                                          nmigrate_disks,
-                                         migrate_disks) < 0) {
+                                         migrate_disks,
+                                         dconn) < 0) {
                 goto cleanup;
             }
         } else {
@@ -4328,7 +4344,8 @@ qemuMigrationRun(virQEMUDriverPtr driver,
     /* cancel any outstanding NBD jobs */
     if (mig && mig->nbd) {
         if (qemuMigrationCancelDriveMirror(driver, vm, ret == 0,
-                                           QEMU_ASYNC_JOB_MIGRATION_OUT) < 0)
+                                           QEMU_ASYNC_JOB_MIGRATION_OUT,
+                                           dconn) < 0)
             ret = -1;
     }
 
@@ -5929,7 +5946,7 @@ qemuMigrationCancel(virQEMUDriverPtr driver,
     }
 
     if (qemuMigrationCancelDriveMirror(driver, vm, false,
-                                       QEMU_ASYNC_JOB_NONE) < 0)
+                                       QEMU_ASYNC_JOB_NONE, NULL) < 0)
         goto endsyncjob;
 
     ret = 0;