[libvirt] [PATCH] qemu: check backing chains even when cgroup is omitted

[Eric Blake]

https://bugzilla.redhat.com/show_bug.cgi?id=896685 points out
a regression caused by commit 38c4a9c - libvirt only labels
the backing chain if the backing chain cache is populated, but
the code to populate the cache was only conditionally performed
if cgroup labeling was necessary.

* src/qemu/qemu_cgroup.c (qemuSetupCgroup): Hoist cache setup...
* src/qemu/qemu_process.c (qemuProcessStart): ...earlier into
caller, where it is now unconditional.
---
 src/qemu/qemu_cgroup.c  | 4 +---
 src/qemu/qemu_process.c | 5 +++++
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index 4fde1af..e65b486 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -234,9 +234,7 @@ int qemuSetupCgroup(virQEMUDriverPtr driver,
         }

         for (i = 0; i < vm->def->ndisks ; i++) {
-            if (qemuDomainDetermineDiskChain(driver, vm->def->disks[i],
-                                             false) < 0 ||
-                qemuSetupDiskCgroup(vm, cgroup, vm->def->disks[i]) < 0)
+            if (qemuSetupDiskCgroup(vm, cgroup, vm->def->disks[i]) < 0)
                 goto cleanup;
         }

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 476e3ed..af8222b 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -3706,6 +3706,11 @@ int qemuProcessStart(virConnectPtr conn,
         goto cleanup;

     VIR_DEBUG("Checking for CDROM and floppy presence");
+    for (i = 0; i < vm->def->ndisks ; i++) {
+        if (qemuDomainDetermineDiskChain(driver, vm->def->disks[i],
+                                         false) < 0)
+            goto cleanup;
+    }
     if (qemuDomainCheckDiskPresence(driver, vm,
                                     flags & VIR_QEMU_PROCESS_START_COLD) < 0)
         goto cleanup;
-- 
1.8.1.2