[libvirt] [PATCH] qemu: snapshot: Mark file becoming backingStore as read-only

[Peter Krempa]

For any backing file we set 'read-only' to true, but didn't do this when
modifying the recorded backing store when creating external snapshots.

This meant that qemu would attempt to open the backing-file read-write.
This would fail for example when selinux is used as qemu doesn't have
write permission for the backing file.

https://bugzilla.redhat.com/show_bug.cgi?id=1781079

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_driver.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 738e8832cc..96e811a893 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -14659,6 +14659,7 @@ qemuDomainSnapshotCreateInactiveExternal(virQEMUDriverPtr driver,
             goto cleanup;

         if (virStorageSourceHasBacking(defdisk->src)) {
+            defdisk->src->readonly = true;
             newsrc->backingStore = g_steal_pointer(&defdisk->src);
         } else {
             virObjectUnref(defdisk->src);
@@ -15510,6 +15511,7 @@ qemuDomainSnapshotDiskUpdateSource(virQEMUDriverPtr driver,
         qemuDomainSnapshotDiskUpdateSourceRenumber(dd->disk->src);

     if (dd->persistdisk) {
+        dd->persistdisk->src->readonly = true;
         dd->persistsrc->backingStore = g_steal_pointer(&dd->persistdisk->src);
         dd->persistdisk->src = g_steal_pointer(&dd->persistsrc);
     }
-- 
2.23.0