[libvirt] [PATCH] qemu: snapshot: inactive external snapshot can't work after libvirtd restart

[Shanzhi Yu]

When create inactive external snapshot, after update disk definitions,
virDomainSaveConfig is needed, if not after restart libvirtd the new snapshot
file definitions in xml will be lost.

Reproduce steps:

1. prepare a shut off guest
$ virsh domstate rhel7 && virsh domblklist rhel7
shut off

Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/rhel7.img

2. create external disk snapshot
$ virsh snapshot-create rhel7 --disk-only && virsh domblklist rhel7
Domain snapshot 1417882967 created
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/rhel7.1417882967

3. restart libvirtd then check guest source file
$ service  libvirtd restart && virsh domblklist rhel7
Redirecting to /bin/systemctl restart  libvirtd.service
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/rhel7.img

This was first reported by Eric Blake
http://www.redhat.com/archives/libvir-list/2014-December/msg00369.html

Signed-off-by: Shanzhi Yu <shyu at redhat.com>
---
 src/qemu/qemu_driver.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 9152cf5..9f8ea0a 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -12847,6 +12847,9 @@ qemuDomainSnapshotCreateInactiveExternal(virQEMUDriverPtr driver,
                 goto cleanup;
             }
             defdisk->src->format = snapdisk->src->format;
+
+            if (virDomainSaveConfig(cfg->configDir, vm->def) < 0)
+                goto cleanup;
         }
     }
 
-- 
2.1.0