[libvirt] [PATCH 1/2] qemu: Save qemuDomainGetStats error

John Ferlan jferlan at redhat.com
Tue Nov 27 16:23:22 UTC 2018


During qemuConnectGetAllDomainStats if qemuDomainGetStats causes
a failure, then when collecting more than one domain's worth of
statistics the loop in virDomainStatsRecordListFree would call
virDomainFree which would call virResetLastError effectively wiping
out the reason we failed leaving the caller with no idea why the
collection failed.

To fix this, let's save the error and restore it prior to return
so that a caller such as 'virsh domstats' doesn't get the generic
"error: An error occurred, but the cause is unknown".

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 src/qemu/qemu_driver.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 7d9e17e72c..2fb8eef609 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -21092,6 +21092,7 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
                              unsigned int flags)
 {
     virQEMUDriverPtr driver = conn->privateData;
+    virErrorPtr save_err = NULL;
     virDomainObjPtr *vms = NULL;
     virDomainObjPtr vm;
     size_t nvms;
@@ -21160,6 +21161,7 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
         if (flags & VIR_CONNECT_GET_ALL_DOMAINS_STATS_BACKING)
             domflags |= QEMU_DOMAIN_STATS_BACKING;
         if (qemuDomainGetStats(conn, vm, stats, &tmp, domflags) < 0) {
+            save_err = virSaveLastError();
             if (HAVE_JOB(domflags) && vm)
                 qemuDomainObjEndJob(driver, vm);
 
@@ -21184,6 +21186,10 @@ qemuConnectGetAllDomainStats(virConnectPtr conn,
  cleanup:
     virDomainStatsRecordListFree(tmpstats);
     virObjectListFreeCount(vms, nvms);
+    if (save_err) {
+        virSetError(save_err);
+        virFreeError(save_err);
+    }
 
     return ret;
 }
-- 
2.17.2




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