[libvirt] [PATCH v2] snapshot: fix rollback failure in transaction mode

[Guannan Ren]

BZ:https://bugzilla.redhat.com/show_bug.cgi?id=843372

when qemu supports the 'transaction' monitor command,
and libvirt's --reuse-ext flag was not specified, libvirt created
a stub file with zero size in first place. After the failure of
QEMU transaction command performing qcow2 snapshots on more than
one drives, the stub file is left behind with non-empty
by the QEMU transaction command.

In order to unlink the file, the patch removes the file size checking.
---
 src/qemu/qemu_driver.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index a410521..d11bd19 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -10833,7 +10833,7 @@ qemuDomainSnapshotUndoSingleDiskActive(struct qemud_driver *driver,
     if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
         VIR_WARN("Unable to release lock on %s", disk->src);
     if (need_unlink && stat(disk->src, &st) == 0 &&
-        st.st_size == 0 && S_ISREG(st.st_mode) && unlink(disk->src) < 0)
+        S_ISREG(st.st_mode) && unlink(disk->src) < 0)
         VIR_WARN("Unable to remove just-created %s", disk->src);
 
     /* Update vm in place to match changes.  */
-- 
1.7.11.2