From ecc34514032017857dcf514d8b7a83973f084e41 Mon Sep 17 00:00:00 2001
Message-Id: <ecc34514032017857dcf514d8b7a83973f084e41.1380112457.git.jdenemar@redhat.com>
From: Eric Blake <eblake@redhat.com>
Date: Mon, 23 Sep 2013 11:10:06 -0600
Subject: [PATCH] qemu: don't leak vm on failure

https://bugzilla.redhat.com/show_bug.cgi?id=1010617

Failure to attach to a domain during 'virsh qemu-attach' left
the list of domains in an odd state:

$ virsh qemu-attach 4176
error: An error occurred, but the cause is unknown

$ virsh list --all
 Id    Name                           State
----------------------------------------------------
 2     foo                            shut off

$ virsh qemu-attach 4176
error: Requested operation is not valid: domain is already active as 'foo'

$ virsh undefine foo
error: Failed to undefine domain foo
error: Requested operation is not valid: cannot undefine transient domain

$ virsh shutdown foo
error: Failed to shutdown domain foo
error: invalid argument: monitor must not be NULL

It all stems from leaving the list of domains unmodified on
the initial failure; we should follow the lead of createXML
which removes vm on failure (the actual initial failure still
needs to be fixed in a later patch, but at least this patch
gets us to the point where we aren't getting stuck with an
unremovable "shut off" transient domain).

While investigating, I also found a leak in qemuDomainCreateXML;
the two functions should behave similarly.  Note that there are
still two unusual paths: if dom is not allocated, the user will
see an OOM error even though the vm remains registered (but oom
errors already indicate tricky cleanup); and if the vm starts
and then quits again all before the job ends, it is possible
to return a non-NULL dom even though the dom will no longer be
useful for anything (but this at least lets the user know their
short-lived vm ran).

* src/qemu/qemu_driver.c (qemuDomainCreateXML): Don't leak vm on
failure to obtain job.
(qemuDomainQemuAttach): Match cleanup of qemuDomainCreateXML.

Signed-off-by: Eric Blake <eblake@redhat.com>
(cherry picked from commit d047b2d9835cbe5090e9eedb11ab69e7e4522f76)
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/qemu_driver.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index eb1a2ce..693dd85 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -1602,8 +1602,11 @@ static virDomainPtr qemuDomainCreateXML(virConnectPtr conn,
 
     def = NULL;
 
-    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
-        goto cleanup; /* XXXX free the 'vm' we created ? */
+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0) {
+        qemuDomainRemoveInactive(driver, vm);
+        vm = NULL;
+        goto cleanup;
+    }
 
     if (qemuProcessStart(conn, driver, vm, NULL, -1, NULL, NULL,
                          VIR_NETDEV_VPORT_PROFILE_OP_CREATE,
@@ -1631,10 +1634,10 @@ static virDomainPtr qemuDomainCreateXML(virConnectPtr conn,
     virDomainAuditStart(vm, "booted", true);
 
     dom = virGetDomain(conn, vm->def->name, vm->def->uuid);
-    if (dom) dom->id = vm->def->id;
+    if (dom)
+        dom->id = vm->def->id;
 
-    if (vm &&
-        qemuDomainObjEndJob(driver, vm) == 0)
+    if (qemuDomainObjEndJob(driver, vm) == 0)
         vm = NULL;
 
 cleanup:
@@ -13885,34 +13888,38 @@ static virDomainPtr qemuDomainQemuAttach(virConnectPtr conn,
 
     def = NULL;
 
-    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
+    if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0) {
+        qemuDomainRemoveInactive(driver, vm);
+        vm = NULL;
         goto cleanup;
+    }
 
     if (qemuProcessAttach(conn, driver, vm, pid,
                           pidfile, monConfig, monJSON) < 0) {
+        if (qemuDomainObjEndJob(driver, vm) > 0)
+            qemuDomainRemoveInactive(driver, vm);
+        vm = NULL;
         monConfig = NULL;
-        goto endjob;
+        goto cleanup;
     }
 
     monConfig = NULL;
 
     dom = virGetDomain(conn, vm->def->name, vm->def->uuid);
-    if (dom) dom->id = vm->def->id;
+    if (dom)
+        dom->id = vm->def->id;
 
-endjob:
-    if (qemuDomainObjEndJob(driver, vm) == 0) {
+    if (qemuDomainObjEndJob(driver, vm) == 0)
         vm = NULL;
-        goto cleanup;
-    }
 
 cleanup:
     virDomainDefFree(def);
-    virObjectUnref(qemuCaps);
     virDomainChrSourceDefFree(monConfig);
     if (vm)
         virObjectUnlock(vm);
     VIR_FREE(pidfile);
     virObjectUnref(caps);
+    virObjectUnref(qemuCaps);
     return dom;
 }
 
-- 
1.8.3.2