On Mon, Feb 18, 2013 at 05:07:45PM +0100, Jiri Denemark wrote:
> Since closeCallbacks were turned into virObjectLockable, we can no
> longer call virQEMUCloseCallbacks APIs from within a registered close
> callback.
> ---
> src/qemu/qemu_conf.c | 19 ++++---------------
> src/qemu/qemu_conf.h | 4 ++++
> src/qemu/qemu_domain.h | 1 +
> src/qemu/qemu_process.c | 10 +++++++++-
> 4 files changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> index edadf36..fc8e152 100644
> --- a/src/qemu/qemu_conf.c
> +++ b/src/qemu/qemu_conf.c
> @@ -825,8 +825,6 @@ virQEMUCloseCallbacksRunOne(void *payload,
> {
> struct virQEMUCloseCallbacksData *data = opaque;
> qemuDriverCloseDefPtr closeDef = payload;
> - unsigned char uuid[VIR_UUID_BUFLEN];
> - char uuidstr[VIR_UUID_STRING_BUFLEN];
> virDomainObjPtr dom;
>
> VIR_DEBUG("conn=%p, thisconn=%p, uuid=%s, cb=%p",
> @@ -835,18 +833,9 @@ virQEMUCloseCallbacksRunOne(void *payload,
> if (data->conn != closeDef->conn || !closeDef->cb)
> return;
>
> - if (virUUIDParse(name, uuid) < 0) {
> - VIR_WARN("Failed to parse %s", (const char *)name);
> - return;
> - }
> - /* We need to reformat uuidstr, because closeDef->cb
> - * might cause the current hash entry to be removed,
> - * which means 'name' will have been free()d
> - */
> - virUUIDFormat(uuid, uuidstr);
> -
> - if (!(dom = virDomainObjListFindByUUID(data->driver->domains, uuid))) {
> - VIR_DEBUG("No domain object with UUID %s", uuidstr);
> + if (!(dom = virDomainObjListFindByUUID(data->driver->domains, name))) {
> + VIR_DEBUG("No domain object with UUID %s",
> + (const char *) name);
> return;
> }
>
> @@ -854,7 +843,7 @@ virQEMUCloseCallbacksRunOne(void *payload,
> if (dom)
> virObjectUnlock(dom);
>
> - virHashRemoveEntry(data->list, uuidstr);
> + virHashRemoveEntry(data->list, name);
> }
>
> void
> diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h
> index 72380dc..b5a3281 100644
> --- a/src/qemu/qemu_conf.h
> +++ b/src/qemu/qemu_conf.h
> @@ -254,6 +254,10 @@ struct qemuDomainDiskInfo {
> int io_status;
> };
>
> +/*
> + * To avoid a certain deadlock this callback must never call any
> + * virQEMUCloseCallbacks* API.
> + */
> typedef virDomainObjPtr (*virQEMUCloseCallback)(virQEMUDriverPtr driver,
> virDomainObjPtr vm,
> virConnectPtr conn);
> diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
> index 905b099..c9d5f8b 100644
> --- a/src/qemu/qemu_domain.h
> +++ b/src/qemu/qemu_domain.h
> @@ -137,6 +137,7 @@ struct _qemuDomainObjPrivate {
>
> bool gotShutdown;
> bool beingDestroyed;
> + bool autoDestroyed;
> char *pidfile;
>
> int nvcpupids;
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index f987618..74406a6 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -4263,7 +4263,8 @@ void qemuProcessStop(virQEMUDriverPtr driver,
> qemuDomainCleanupRun(driver, vm);
>
> /* Stop autodestroy in case guest is restarted */
> - qemuProcessAutoDestroyRemove(driver, vm);
> + if (!priv->autoDestroyed)
> + qemuProcessAutoDestroyRemove(driver, vm);
>
> /* now that we know it's stopped call the hook if present */
> if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) {
> @@ -4647,8 +4648,15 @@ qemuProcessAutoDestroy(virQEMUDriverPtr driver,
> goto cleanup;
>
> VIR_DEBUG("Killing domain");
> +
> + /* We need to prevent qemuProcessStop from removing this function from
> + * closeCallbacks since that would cause a deadlock.
> + */
> + priv->autoDestroyed = true;
> qemuProcessStop(driver, dom, VIR_DOMAIN_SHUTOFF_DESTROYED,
> VIR_QEMU_PROCESS_STOP_MIGRATED);
> + priv->autoDestroyed = false;
> +
> virDomainAuditStop(dom, "destroyed");
> event = virDomainEventNewFromObj(dom,
> VIR_DOMAIN_EVENT_STOPPED,
Slightly gross, but it'll do for now.
ACK
Daniel
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