On Mon, Mar 21, 2011 at 10:36:55AM +0100, Thibault VINCENT wrote:
>From 827261dbe2ab8f1cfd8c84df14bb42fd04df2307 Mon Sep 17 00:00:00
2001
From: Thibault VINCENT <thibault.vincent(a)smartjog.com>
Date: Mon, 21 Mar 2011 10:18:06 +0100
Subject: [PATCH] qemu: add two hook script events "prepare" and
"release"
* Fix for bug #618970
* The "prepare" hook is called very early in the VM statup process
before device labeling, so that it can allocate ressources not
managed by libvirt, such as DRBD, or for instance create missing
bridges and vlan interfaces.
* To shutdown these devices, the "release" hook is also required at
the very end of the VM destruction.
Signed-off-by: Thibault VINCENT <thibault.vincent(a)smartjog.com>
---
src/qemu/qemu_process.c | 26 ++++++++++++++++++++++++++
src/util/hooks.c | 4 +++-
src/util/hooks.h | 2 ++
3 files changed, 31 insertions(+), 1 deletions(-)
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 793a43c..7831c3b 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -1927,6 +1927,22 @@ int qemuProcessStart(virConnectPtr conn,
vm->def->id = driver->nextvmid++;
+ /* Run a early hook to set-up missing devices */
+ if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) {
+ char *xml = virDomainDefFormat(vm->def, 0);
+ int hookret;
+
+ hookret = virHookCall(VIR_HOOK_DRIVER_QEMU, vm->def->name,
+ VIR_HOOK_QEMU_OP_PREPARE, VIR_HOOK_SUBOP_BEGIN,
NULL, xml);
+ VIR_FREE(xml);
+
+ /*
+ * If the script raised an error abort the launch
+ */
+ if (hookret < 0)
+ goto cleanup;
+ }
Hum, the main problem I see there is that we may fail startup there
and go to cleanup. In that case the domain is not started but no hook is
called to reverse the operation. I wonder if VIR_HOOK_QEMU_OP_RELEASE
shouldn't be called in the cleanup ... if present, to avoid resource
leak when startup fails.
/* Must be run before security labelling */
VIR_DEBUG0("Preparing host devices");
if (qemuPrepareHostDevices(driver, vm->def) < 0)
@@ -2419,6 +2435,16 @@ retry:
VIR_FREE(priv->vcpupids);
priv->nvcpupids = 0;
+ /* The "release" hook cleans up additional ressources */
+ if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) {
+ char *xml = virDomainDefFormat(vm->def, 0);
+
+ /* we can't stop the operation even if the script raised an
error */
+ virHookCall(VIR_HOOK_DRIVER_QEMU, vm->def->name,
+ VIR_HOOK_QEMU_OP_RELEASE, VIR_HOOK_SUBOP_END, NULL,
xml);
+ VIR_FREE(xml);
+ }
+
That's okay, but possibly not sufficient.
if (vm->newDef) {
virDomainDefFree(vm->def);
vm->def = vm->newDef;
diff --git a/src/util/hooks.c b/src/util/hooks.c
index 5ba2036..c258318 100644
--- a/src/util/hooks.c
+++ b/src/util/hooks.c
@@ -70,8 +70,10 @@ VIR_ENUM_IMPL(virHookSubop, VIR_HOOK_SUBOP_LAST,
"end")
VIR_ENUM_IMPL(virHookQemuOp, VIR_HOOK_QEMU_OP_LAST,
+ "prepare",
"start",
- "stopped")
+ "stopped",
+ "release")
prepare should be added after stopped to avoid changing the order.
VIR_ENUM_IMPL(virHookLxcOp, VIR_HOOK_LXC_OP_LAST,
"start",
diff --git a/src/util/hooks.h b/src/util/hooks.h
index f311ed1..66b378a 100644
--- a/src/util/hooks.h
+++ b/src/util/hooks.h
@@ -52,8 +52,10 @@ enum virHookSubopType {
};
enum virHookQemuOpType {
+ VIR_HOOK_QEMU_OP_PREPARE, /* domain startup initiated */
VIR_HOOK_QEMU_OP_START, /* domain is about to start */
VIR_HOOK_QEMU_OP_STOPPED, /* domain has stopped */
+ VIR_HOOK_QEMU_OP_RELEASE, /* domain destruction is over */
same thing, only add at the end.
VIR_HOOK_QEMU_OP_LAST,
};
Fixing the 2 last problems is trivial and I did it in my tree, but I
don't feel like commiting this without handling the failure to start
the domain (running VIR_HOOK_QEMU_OP_RELEASE with a new virHookSubopType
VIR_HOOK_SUBOP_FAILED for example).
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit
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