[libvirt] [PATCH 1/7] qemu: Alter error path cleanup for qemuDomainAttachHostSCSIDevice

[Ján Tomko]

On Fri, Jul 15, 2016 at 07:50:21AM -0400, John Ferlan wrote:
>Based on recent review comment - rather than have a spate of goto failxxxx,
>change to a boolean based model. Ensures that the original error can be
>preserved and cleanup is a bit more orderly if more objects are added.
>
>Signed-off-by: John Ferlan <jferlan at redhat.com>
>---
> src/qemu/qemu_hotplug.c | 20 +++++++++-----------
> 1 file changed, 9 insertions(+), 11 deletions(-)
>
>diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
>index 04e11b4..10120aa 100644
>--- a/src/qemu/qemu_hotplug.c
>+++ b/src/qemu/qemu_hotplug.c
>@@ -1874,6 +1874,7 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn,
>     char *drvstr = NULL;
>     bool teardowncgroup = false;
>     bool teardownlabel = false;
>+    bool cleanupAddDrive = false;

driveAdded is shorter

>
>     if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE_SCSI_GENERIC)) {
>         virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>@@ -1935,17 +1936,17 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn,
>     if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0)
>         goto cleanup;
>
>-    /* Attach the device - 2 step process */
>     qemuDomainObjEnterMonitor(driver, vm);
>
>     if (qemuMonitorAddDrive(priv->mon, drvstr) < 0)
>-        goto failadddrive;
>+        goto monitor_error;
>+    cleanupAddDrive = true;
>
>     if (qemuMonitorAddDevice(priv->mon, devstr) < 0)
>-        goto failadddevice;
>+        goto monitor_error;
>
>     if (qemuDomainObjExitMonitor(driver, vm) < 0)
>-        goto failexitmonitor;
>+        goto cleanup;
>
>     virDomainAuditHostdev(vm, hostdev, "attach", true);
>
>@@ -1968,21 +1969,18 @@ qemuDomainAttachHostSCSIDevice(virConnectPtr conn,
>     VIR_FREE(devstr);
>     return ret;
>
>- failadddevice:
>+ monitor_error:

can be 'exit_monitor' to match what we already use.

>     orig_err = virSaveLastError();
>-    if (qemuMonitorDriveDel(priv->mon, drvstr) < 0)
>+    if (cleanupAddDrive && qemuMonitorDriveDel(priv->mon, drvstr) < 0) {
>         VIR_WARN("Unable to remove drive %s (%s) after failed "
>                  "qemuMonitorAddDevice",
>                  drvstr, devstr);
>+    }
>+    ignore_value(qemuDomainObjExitMonitor(driver, vm));

The error reported by qemuDomainObjExitMonitor ('domain is no longer
running') could be more important than the original error.

I would leave it where it was.

Also, it's possible that ExitMonitor can no longer fail now that we take
a job for cleaning up after EOF.

ACK either way.

Jan

>     if (orig_err) {
>         virSetError(orig_err);
>         virFreeError(orig_err);
>     }
>-
>- failadddrive:
>-    ignore_value(qemuDomainObjExitMonitor(driver, vm));
>-
>- failexitmonitor:
>     virDomainAuditHostdev(vm, hostdev, "attach", false);
>
>     goto cleanup;
>-- 
>2.5.5
>
>--
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