[libvirt] [PATCH v5 2/2] qemu: support to drop disk with 'optional' startupPolicy

[Guannan Ren]

Go through disks of guest, if one disk doesn't exist or its backing
chain is broken, with 'optional' startupPolicy, for CDROM and Floppy
we only discard its source path definition in xml, for disks we drop
it from disk list and free it.
---
 include/libvirt/libvirt.h.in |  1 +
 src/qemu/qemu_domain.c       | 77 +++++++++++++++++++++++++++++++++++---------
 2 files changed, 62 insertions(+), 16 deletions(-)

diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index c0eb25b..3888ba5 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -4728,6 +4728,7 @@ typedef void (*virConnectDomainEventBlockJobCallback)(virConnectPtr conn,
  */
 typedef enum {
     VIR_DOMAIN_EVENT_DISK_CHANGE_MISSING_ON_START = 0, /* oldSrcPath is set */
+    VIR_DOMAIN_EVENT_HARDDISK_DROP_MISSING_ON_START = 1,
 
 #ifdef VIR_ENUM_SENTINELS
     VIR_DOMAIN_EVENT_DISK_CHANGE_LAST
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 1ff802c..5da6e18 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2027,13 +2027,59 @@ cleanup:
 }
 
 static int
+qemuDomainCheckRemoveOptionalDisk(virQEMUDriverPtr driver,
+                                  virDomainObjPtr vm,
+                                  virDomainDiskDefPtr disk,
+                                  size_t *nextdisk)
+{
+    char uuid[VIR_UUID_STRING_BUFLEN];
+    virDomainEventPtr event = NULL;
+    virDomainDiskDefPtr del_disk = NULL;
+
+    virUUIDFormat(vm->def->uuid, uuid);
+
+    VIR_DEBUG("Dropping disk '%s' on domain '%s' (UUID '%s') "
+              "due to inaccessible source '%s'",
+              disk->dst, vm->def->name, uuid, disk->src);
+
+    if (disk->device == VIR_DOMAIN_DISK_DEVICE_CDROM ||
+        disk->device == VIR_DOMAIN_DISK_DEVICE_FLOPPY) {
+
+        event = virDomainEventDiskChangeNewFromObj(vm, disk->src, NULL,
+                                                   disk->info.alias,
+                                                   VIR_DOMAIN_EVENT_DISK_CHANGE_MISSING_ON_START);
+       /* For cdrom or floppy, we only remove its source definition
+        * So the nextdisk need to point to next disk.
+        */
+        (*nextdisk)++;
+        VIR_FREE(disk->src);
+    } else {
+        event = virDomainEventDiskChangeNewFromObj(vm, disk->src, NULL,
+                                                   disk->info.alias,
+                                                   VIR_DOMAIN_EVENT_HARDDISK_DROP_MISSING_ON_START);
+
+        if (!(del_disk = virDomainDiskRemoveByName(vm->def, disk->src))) {
+            virReportError(VIR_ERR_INVALID_ARG,
+                           _("no source device %s"), disk->src);
+            return -1;
+        }
+        virDomainDiskDefFree(del_disk);
+    }
+
+    if (event)
+        qemuDomainEventQueue(driver, event);
+
+    return 0;
+}
+
+static int
 qemuDomainCheckDiskStartupPolicy(virQEMUDriverPtr driver,
                                  virDomainObjPtr vm,
                                  virDomainDiskDefPtr disk,
-                                 bool cold_boot)
+                                 bool cold_boot,
+                                 size_t *nextdisk)
 {
     char uuid[VIR_UUID_STRING_BUFLEN];
-    virDomainEventPtr event = NULL;
     int startupPolicy = disk->startupPolicy;
 
     virUUIDFormat(vm->def->uuid, uuid);
@@ -2057,16 +2103,8 @@ qemuDomainCheckDiskStartupPolicy(virQEMUDriverPtr driver,
     }
 
     virResetLastError();
-    VIR_DEBUG("Dropping disk '%s' on domain '%s' (UUID '%s') "
-              "due to inaccessible source '%s'",
-              disk->dst, vm->def->name, uuid, disk->src);
-
-    event = virDomainEventDiskChangeNewFromObj(vm, disk->src, NULL, disk->info.alias,
-                                               VIR_DOMAIN_EVENT_DISK_CHANGE_MISSING_ON_START);
-    if (event)
-        qemuDomainEventQueue(driver, event);
-
-    VIR_FREE(disk->src);
+    if (qemuDomainCheckRemoveOptionalDisk(driver, vm, disk, nextdisk) < 0)
+        goto error;
 
     return 0;
 
@@ -2082,21 +2120,28 @@ qemuDomainCheckDiskPresence(virQEMUDriverPtr driver,
     int ret = -1;
     size_t i;
     virDomainDiskDefPtr disk;
+    size_t count = vm->def->ndisks;
+    size_t nextdisk = 0;
+
 
     VIR_DEBUG("Checking for disk presence");
-    for (i = 0; i < vm->def->ndisks; i++) {
-        disk = vm->def->disks[i];
+    for (i = 0; i < count; i++) {
+        disk = vm->def->disks[nextdisk];
+
 
         if (!disk->src)
             continue;
 
         if (qemuDomainDetermineDiskChain(driver, disk, false) >= 0 &&
-            qemuDiskChainCheckBroken(disk) >= 0)
+            qemuDiskChainCheckBroken(disk) >= 0) {
+            nextdisk++;
             continue;
+        }
 
         if (disk->startupPolicy) {
             if (qemuDomainCheckDiskStartupPolicy(driver, vm, disk,
-                                                 cold_boot) >= 0)
+                                                 cold_boot,
+                                                 &nextdisk) >= 0)
                 continue;
         }
 
-- 
1.8.3.1