[libvirt] [PATCH 2/5] qemu: Avoid using stale data in virDomainGetBlockInfo
Generally, every API that is going to begin a job should do that before
fetching data from vm->def. However, qemuDomainGetBlockInfo does not
know whether it will have to start a job or not before checking vm->def.
To avoid using disk alias that might have been freed while we were
waiting for a job, we use its copy. In case the disk was removed in the
meantime, we will fail with "cannot find statistics for device '...'"
error message.
Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com>
---
src/qemu/qemu_driver.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 8823187..9db0c49 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -9780,10 +9780,12 @@ cleanup:
}
-static int qemuDomainGetBlockInfo(virDomainPtr dom,
- const char *path,
- virDomainBlockInfoPtr info,
- unsigned int flags) {
+static int
+qemuDomainGetBlockInfo(virDomainPtr dom,
+ const char *path,
+ virDomainBlockInfoPtr info,
+ unsigned int flags)
+{
virQEMUDriverPtr driver = dom->conn->privateData;
virDomainObjPtr vm;
int ret = -1;
@@ -9795,6 +9797,7 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,
int idx;
int format;
virQEMUDriverConfigPtr cfg = NULL;
+ char *alias = NULL;
virCheckFlags(0, -1);
@@ -9901,13 +9904,16 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,
virDomainObjIsActive(vm)) {
qemuDomainObjPrivatePtr priv = vm->privateData;
+ if (VIR_STRDUP(alias, disk->info.alias) < 0)
+ goto cleanup;
+
if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_QUERY) < 0)
goto cleanup;
if (virDomainObjIsActive(vm)) {
qemuDomainObjEnterMonitor(driver, vm);
ret = qemuMonitorGetBlockExtent(priv->mon,
- disk->info.alias,
+ alias,
&info->allocation);
qemuDomainObjExitMonitor(driver, vm);
} else {
@@ -9921,6 +9927,7 @@ static int qemuDomainGetBlockInfo(virDomainPtr dom,
}
cleanup:
+ VIR_FREE(alias);
virStorageFileFreeMetadata(meta);
VIR_FORCE_CLOSE(fd);
if (vm)
--
1.8.5.2