qemu: Move the shared disk adding and sgio setting prior to attaching

The disk def could be free'ed by qemuDomainChangeEjectableMedia,
which can thus cause crash if we reference the disk pointer. On
the other hand, we have to remove the added shared disk entry from
the table on error codepath.

src/qemu/qemu_driver.c

@@ -5714,6 +5714,12 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
         goto end;
     }
 
+    if (qemuAddSharedDisk(driver, disk, vm->def->name) < 0)
+        goto end;
+
+    if (qemuSetUnprivSGIO(disk) < 0)
+        goto end;
+
     if (qemuDomainDetermineDiskChain(driver, disk, false) < 0)
         goto end;
 
@@ -5727,6 +5733,7 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
         if (qemuSetupDiskCgroup(vm, cgroup, disk) < 0)
             goto end;
     }
+
     switch (disk->device)  {
     case VIR_DOMAIN_DISK_DEVICE_CDROM:
     case VIR_DOMAIN_DISK_DEVICE_FLOPPY:
@@ -5765,16 +5772,9 @@ qemuDomainAttachDeviceDiskLive(virConnectPtr conn,
                      NULLSTR(disk->src));
     }
 
-    if (ret == 0) {
-        if (qemuAddSharedDisk(driver, disk, vm->def->name) < 0)
-            VIR_WARN("Failed to add disk '%s' to shared disk table",
-                     disk->src);
-
-        if (qemuSetUnprivSGIO(disk) < 0)
-            VIR_WARN("Failed to set unpriv_sgio of disk '%s'", disk->src);
-    }
-
 end:
+    if (ret != 0)
+        ignore_value(qemuRemoveSharedDisk(driver, disk, vm->def->name));
     if (cgroup)
         virCgroupFree(&cgroup);
     return ret;
@@ -5889,11 +5889,8 @@ qemuDomainDetachDeviceDiskLive(virQEMUDriverPtr driver,
         break;
     }
 
-    if (ret == 0) {
-        if (qemuRemoveSharedDisk(driver, disk, vm->def->name) < 0)
-             VIR_WARN("Failed to remove disk '%s' from shared disk table",
-                      disk->src);
-    }
+    if (ret == 0)
+        ignore_value(qemuRemoveSharedDisk(driver, disk, vm->def->name));
 
     return ret;
 }