qemu: Don't track quiesced state of FSs

https://bugzilla.redhat.com/show_bug.cgi?id=1160084

As of b6d4dad11b (1.2.5) we are trying to keep the status of FSFreeze
in the guest. Even though I've tried to fixed couple of corner cases
(6ea54769ba18), it occurred to me just recently, that the approach is
broken by design. Firstly, there are many other ways to talk to
qemu-ga (even through libvirt) that filesystems can be thawed (e.g.
qemu-agent-command) without libvirt noticing. Moreover, there are
plenty of ways to thaw filesystems without even qemu-ga noticing (yes,
qemu-ga keeps internal track of FSFreeze status). So, instead of
keeping the track ourselves, or asking qemu-ga for stale state, it's
the best to let qemu-ga deal with that (and possibly let guest kernel
propagate an error).

Moreover, there's one bug with the following approach, if fsfreeze
command failed, we've executed fsthaw subsequently. So issuing
domfsfreeze in virsh gave the following result:

virsh # domfsfreeze gentoo
Froze 1 filesystem(s)

virsh # domfsfreeze gentoo
error: Unable to freeze filesystems
error: internal error: unable to execute QEMU agent command 'guest-fsfreeze-freeze': The command guest-fsfreeze-freeze has been disabled for this instance

virsh # domfsfreeze gentoo
Froze 1 filesystem(s)

virsh # domfsfreeze gentoo
error: Unable to freeze filesystems
error: internal error: unable to execute QEMU agent command 'guest-fsfreeze-freeze': The command guest-fsfreeze-freeze has been disabled for this instance

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 6513c78c84710a6f942b6e6a39f429749df09bba..4061ca17795cc80e260aaca34769996053868441 100644 (file)
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -563,9 +563,6 @@ qemuDomainObjPrivateXMLFormat(virBufferPtr buf, void *data)
         virBufferAddLit(buf, "</devices>\n");
     }
 
-    if (priv->quiesced)
-        virBufferAddLit(buf, "<quiesced/>\n");
-
     return 0;
 }
 
@@ -750,8 +747,6 @@ qemuDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt, void *data)
     }
     VIR_FREE(nodes);
 
-    priv->quiesced = virXPathBoolean("boolean(./quiesced)", ctxt) == 1;
-
     return 0;
 
  error:

diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index e4ea4ceef0849d3526277785c1ea4bb43e6fd634..ebb282a7a2dcc6b210374f1b2cb6302fdae4ab56 100644 (file)
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -187,8 +187,6 @@ struct _qemuDomainObjPrivate {
     char **qemuDevices; /* NULL-terminated list of devices aliases known to QEMU */
 
     bool hookRun;  /* true if there was a hook run over this domain */
-
-    bool quiesced; /* true if filesystems are quiesced */
 };
 
 typedef enum {

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 07da3e335d4af6679ab6164c52c72dc1ccf4134e..ad5f70a85f5a4e2ea88eb16f9998da3e63c5531c 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -12704,34 +12704,17 @@ qemuDomainPrepareDiskChainElement(virQEMUDriverPtr driver,
  * is sent but failed, and number of frozen filesystems on success. If -2 is
  * returned, FSThaw should be called revert the quiesced status. */
 static int
-qemuDomainSnapshotFSFreeze(virQEMUDriverPtr driver,
+qemuDomainSnapshotFSFreeze(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
                            virDomainObjPtr vm,
                            const char **mountpoints,
                            unsigned int nmountpoints)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
-    virQEMUDriverConfigPtr cfg;
     int frozen;
 
-    if (priv->quiesced) {
-        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
-                       _("domain is already quiesced"));
-        return -1;
-    }
-
     if (!qemuDomainAgentAvailable(priv, true))
         return -1;
 
-    priv->quiesced = true;
-
-    cfg = virQEMUDriverGetConfig(driver);
-    if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0) {
-        priv->quiesced = false;
-        virObjectUnref(cfg);
-        return -1;
-    }
-    virObjectUnref(cfg);
-
     qemuDomainObjEnterAgent(vm);
     frozen = qemuAgentFSFreeze(priv->agent, mountpoints, nmountpoints);
     qemuDomainObjExitAgent(vm);
@@ -12741,24 +12724,17 @@ qemuDomainSnapshotFSFreeze(virQEMUDriverPtr driver,
 
 /* Return -1 on error, otherwise number of thawed filesystems. */
 static int
-qemuDomainSnapshotFSThaw(virQEMUDriverPtr driver,
+qemuDomainSnapshotFSThaw(virQEMUDriverPtr driver ATTRIBUTE_UNUSED,
                          virDomainObjPtr vm,
                          bool report)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
-    virQEMUDriverConfigPtr cfg;
     int thawed;
     virErrorPtr err = NULL;
 
     if (!qemuDomainAgentAvailable(priv, report))
         return -1;
 
-    if (!priv->quiesced && report) {
-        virReportError(VIR_ERR_OPERATION_INVALID, "%s",
-                       _("domain is not quiesced"));
-        return -1;
-    }
-
     qemuDomainObjEnterAgent(vm);
     if (!report)
         err = virSaveLastError();
@@ -12769,18 +12745,6 @@ qemuDomainSnapshotFSThaw(virQEMUDriverPtr driver,
 
     virFreeError(err);
 
-    if (!report || thawed >= 0) {
-        priv->quiesced = false;
-
-        cfg = virQEMUDriverGetConfig(driver);
-        if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0) {
-            /* Revert the statuses when we failed to save them. */
-            priv->quiesced = true;
-            thawed = -1;
-        }
-        virObjectUnref(cfg);
-    }
-
     return thawed;
 }
 
@@ -18033,10 +17997,6 @@ qemuDomainFSFreeze(virDomainPtr dom,
     }
 
     ret = qemuDomainSnapshotFSFreeze(driver, vm, mountpoints, nmountpoints);
-    if (ret == -2) {
-        qemuDomainSnapshotFSThaw(driver, vm, false);
-        ret = -1;
-    }
 
  endjob:
     if (!qemuDomainObjEndJob(driver, vm))

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index c3ee40b5579eae6caabc238110a5b28703b9da94..382d8029ab2f21288f6a9b8abd794e4278037a63 100644 (file)
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -539,10 +539,6 @@ qemuProcessHandleReset(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
     priv = vm->privateData;
     if (priv->agent)
         qemuAgentNotifyEvent(priv->agent, QEMU_AGENT_EVENT_RESET);
-    /* Clear some domain runtime information. For instance,
-     * fsfreeze won't survive domain reset. This, however,
-     * required the domain status file to be rewritten onto disk. */
-    priv->quiesced = false;
 
     if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm) < 0)
         VIR_WARN("Failed to save status on vm %s", vm->def->name);
@@ -4985,7 +4981,6 @@ void qemuProcessStop(virQEMUDriverPtr driver,
 
     virPortAllocatorRelease(driver->migrationPorts, priv->nbdPort);
     priv->nbdPort = 0;
-    priv->quiesced = false;
 
     if (priv->agent) {
         qemuAgentClose(priv->agent);