From b80814d0e06895d7dce41eb3c65b88fa4ee604b1 Mon Sep 17 00:00:00 2001
Message-Id: <b80814d0e06895d7dce41eb3c65b88fa4ee604b1@dist-git>
From: Eric Blake <eblake@redhat.com>
Date: Wed, 17 Dec 2014 03:09:01 -0700
Subject: [PATCH] getstats: start giving offline block stats

https://bugzilla.redhat.com/show_bug.cgi?id=1041569

I noticed that for an offline domain, 'virsh domstats --block $dom'
was producing just the domain name, with no stats.  But the older
'virsh domblkinfo' works just fine on offline domains.  This patch
starts to get us closer, by at least reporting the disk names for
an offline domain.

With this patch, I now see the following for an offline domain
with one qcow2 disk and an empty cdrom drive:
$ virsh domstats --block foo
Domain: 'foo'
  block.count=2
  block.0.name=hda
  block.1.name=hdc

* src/qemu/qemu_driver.c (qemuDomainGetStatsBlock): Don't short-circuit
output of block name.

Signed-off-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit 56b21dfe0c12867fa1dc3715145a61017e6928f1)
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/qemu_driver.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 33a93f1..f0935d6 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -18019,19 +18019,20 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
     int rc;
     virHashTablePtr stats = NULL;
     qemuDomainObjPrivatePtr priv = dom->privateData;
+    bool abbreviated = false;
 
-    if (!HAVE_JOB(privflags) || !virDomainObjIsActive(dom))
-        return 0; /* it's ok, just go ahead silently */
+    if (!HAVE_JOB(privflags) || !virDomainObjIsActive(dom)) {
+        abbreviated = true; /* it's ok, just go ahead silently */
+    } else {
+        qemuDomainObjEnterMonitor(driver, dom);
+        rc = qemuMonitorGetAllBlockStatsInfo(priv->mon, &stats);
+        ignore_value(qemuMonitorBlockStatsUpdateCapacity(priv->mon, stats));
+        qemuDomainObjExitMonitor(driver, dom);
 
-    qemuDomainObjEnterMonitor(driver, dom);
-    rc = qemuMonitorGetAllBlockStatsInfo(priv->mon, &stats);
-    ignore_value(qemuMonitorBlockStatsUpdateCapacity(priv->mon, stats));
-    qemuDomainObjExitMonitor(driver, dom);
-
-    if (rc < 0) {
-        virResetLastError();
-        ret = 0; /* still ok, again go ahead silently */
-        goto cleanup;
+        if (rc < 0) {
+            virResetLastError();
+            abbreviated = true; /* still ok, again go ahead silently */
+        }
     }
 
     QEMU_ADD_COUNT_PARAM(record, maxparams, "block", dom->def->ndisks);
@@ -18042,9 +18043,12 @@ qemuDomainGetStatsBlock(virQEMUDriverPtr driver,
 
         QEMU_ADD_NAME_PARAM(record, maxparams, "block", i, disk->dst);
 
-        if (!disk->info.alias ||
-            !(entry = virHashLookup(stats, disk->info.alias)))
+        if (abbreviated || !disk->info.alias ||
+            !(entry = virHashLookup(stats, disk->info.alias))) {
+            /* FIXME: we could still look up sizing by sharing code
+             * with qemuDomainGetBlockInfo */
             continue;
+        }
 
         QEMU_ADD_BLOCK_PARAM_LL(record, maxparams, i,
                                 "rd.reqs", entry->rd_req);
-- 
2.2.0