Re: [libvirt] [PATCH 12/13] Add support for an explicit IO error event

22 Mar 2010

On Fri, Mar 19, 2010 at 03:39:00PM +0000, Daniel P. Berrange wrote:
...
This introduces a new event type
VIR_DOMAIN_EVENT_ID_IO_ERROR
This event includes the action that is about to be taken
as a result of the watchdog triggering
typedef enum {
     VIR_DOMAIN_EVENT_IO_ERROR_NONE = 0,
     VIR_DOMAIN_EVENT_IO_ERROR_PAUSE,
     VIR_DOMAIN_EVENT_IO_ERROR_REPORT,
  } virDomainEventIOErrorAction;
okay
...
In addition is has the source path of the disk that had the
error and its unique device alias. It does not include the
target device name (/dev/sda), since this would preclude
triggering IO errors from other file backed devices (eg
serial ports connected to a file)
Thus there is a new callback definition for this event type
typedef void (*virConnectDomainEventIOErrorCallback)(virConnectPtr conn,
                                                     virDomainPtr dom,
                                                     const char *srcPath,
                                                     const char *devAlias,
                                                     int action,
                                                     void *opaque);
okay

[...]
...
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -1858,6 +1858,17 @@ typedef void (*virConnectDomainEventWatchdogCallback)(virConnectPtr conn,
                                                       virDomainPtr dom,
                                                       int action,
                                                       void *opaque);
+typedef enum {
+    VIR_DOMAIN_EVENT_IO_ERROR_NONE = 0,
+    VIR_DOMAIN_EVENT_IO_ERROR_PAUSE,
+    VIR_DOMAIN_EVENT_IO_ERROR_REPORT,
+} virDomainEventIOErrorAction;
again let's describe the parameters in the header as this is the only
  place (beside those list archives) where the semantic is described
...
+typedef void (*virConnectDomainEventIOErrorCallback)(virConnectPtr conn,
+                                                     virDomainPtr dom,
+                                                     const char *srcPath,
+                                                     const char *devAlias,
+                                                     int action,
+                                                     void *opaque);
/* Use this to cast the event specific callback into the generic one
  * for use for virDomainEventRegister */
@@ -1869,6 +1880,7 @@ typedef enum {
     VIR_DOMAIN_EVENT_ID_REBOOT = 1,          /* virConnectDomainEventGenericCallback */
     VIR_DOMAIN_EVENT_ID_RTC_CHANGE = 2,      /* virConnectDomainEventRTCChangeCallback */
     VIR_DOMAIN_EVENT_ID_WATCHDOG = 3,        /* virConnectDomainEventWatchdogCallback */
+    VIR_DOMAIN_EVENT_ID_IO_ERROR = 4,        /* virConnectDomainEventIOErrorCallback */
/*
      * NB: this enum value will increase over time as new events are
[...]
...

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index ceba5db..71cca5c 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -747,6 +747,26 @@ findDomainDiskByPath(virDomainObjPtr vm,
     return NULL;
 }
+static virDomainDiskDefPtr
+findDomainDiskByAlias(virDomainObjPtr vm,
+                      const char *alias)
+{
+    int i;
+
+    for (i = 0; i < vm->def->ndisks; i++) {
+        virDomainDiskDefPtr disk;
+
+        disk = vm->def->disks[i];
+        if (disk->info.alias != NULL && STREQ(disk->info.alias, alias))
+            return disk;
+    }
+
+    qemuReportError(VIR_ERR_INTERNAL_ERROR,
+                    _("no disk found with alias %s"),
+                    alias);
+    return NULL;
+}
+
 static int
 getVolumeQcowPassphrase(virConnectPtr conn,
                         virDomainDiskDefPtr disk,
@@ -928,12 +948,49 @@ qemuHandleDomainWatchdog(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
 }
+static int
+qemuHandleDomainIOError(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
+                        virDomainObjPtr vm,
+                        const char *diskAlias,
+                        int action)
+{
+    struct qemud_driver *driver = qemu_driver;
+    virDomainEventPtr event;
+    const char *srcPath;
+    const char *devAlias;
+    virDomainDiskDefPtr disk;
+
+    virDomainObjLock(vm);
+    disk = findDomainDiskByAlias(vm, diskAlias);
+
+    if (disk) {
+        srcPath = disk->src;
+        devAlias = disk->info.alias;
+    } else {
+        srcPath = "";
+        devAlias = "";
+    }
+
+    event = virDomainEventIOErrorNewFromObj(vm, srcPath, devAlias, action);
+    virDomainObjUnlock(vm);
+
+    if (event) {
+        qemuDriverLock(driver);
+        qemuDomainEventQueue(driver, event);
+        qemuDriverUnlock(driver);
+    }
+
+    return 0;
+}
+
+
 static qemuMonitorCallbacks monitorCallbacks = {
     .eofNotify = qemuHandleMonitorEOF,
     .diskSecretLookup = findVolumeQcowPassphrase,
     .domainReset = qemuHandleDomainReset,
     .domainRTCChange = qemuHandleDomainRTCChange,
     .domainWatchdog = qemuHandleDomainWatchdog,
+    .domainIOError = qemuHandleDomainIOError,
 };
okay,

ACK,

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel@veillard.com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/

    