[libvirt] [PATCH v3 05/13] Make virDomainObjList self-locking via virObjectLockable

[Jiri Denemark]

On Fri, Feb 01, 2013 at 11:18:27 +0000, Daniel P. Berrange wrote:
> From: "Daniel P. Berrange" <berrange at redhat.com>
> 
> Switch virDomainObjList to inherit from virObjectLockable and
> make all the APIs acquire/release the mutex when running. This
> makes virDomainObjList completely self-locking and no longer
> reliant on the hypervisor driver locks
> ---
>  src/conf/domain_conf.c | 75 ++++++++++++++++++++++++++++++++++++++++----------
>  1 file changed, 61 insertions(+), 14 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index 79da5eb..a1e899f 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -60,7 +60,7 @@ verify(VIR_DOMAIN_VIRT_LAST <= 32);
>  
>  
>  struct _virDomainObjList {
> -    virObject parent;
> +    virObjectLockable parent;
>  
>      /* uuid string -> virDomainObj  mapping
>       * for O(1), lockless lookup-by-uuid */
> @@ -715,7 +715,7 @@ static int virDomainObjOnceInit(void)
>                                            virDomainObjDispose)))
>          return -1;
>  
> -    if (!(virDomainObjListClass = virClassNew(virClassForObject(),
> +    if (!(virDomainObjListClass = virClassNew(virClassForObjectLockable(),
>                                                "virDomainObjList",
>                                                sizeof(virDomainObjList),
>                                                virDomainObjListDispose)))

These two hunks should go to 3/13.

...
> @@ -1880,25 +1886,32 @@ void virDomainObjAssignDef(virDomainObjPtr domain,
>   * current def is Live
>   *
>   */
> -virDomainObjPtr virDomainObjListAdd(virDomainObjListPtr doms,
> -                                    virCapsPtr caps,
> -                                    const virDomainDefPtr def,
> -                                    unsigned int flags,
> -                                    virDomainDefPtr *oldDef)
> +static virDomainObjPtr
> +virDomainObjListAddLocked(virDomainObjListPtr doms,
> +                          virCapsPtr caps,
> +                          const virDomainDefPtr def,
> +                          unsigned int flags,
> +                          virDomainDefPtr *oldDef)
>  {
>      virDomainObjPtr vm;
>      char uuidstr[VIR_UUID_STRING_BUFLEN];
> +
>      if (oldDef)
>          *oldDef = false;
>  
> +    virUUIDFormat(def->uuid, uuidstr);
> +
>      /* See if a VM with matching UUID already exists */
> -    if ((vm = virDomainObjListFindByUUID(doms, def->uuid))) {
> +    if ((vm = virHashLookup(doms->objs, uuidstr))) {
> +        virObjectLock(vm);
>          /* UUID matches, but if names don't match, refuse it */
>          if (STRNEQ(vm->def->name, def->name)) {
>              virUUIDFormat(vm->def->uuid, uuidstr);
>              virReportError(VIR_ERR_OPERATION_FAILED,
>                             _("domain '%s' is already defined with uuid %s"),
>                             vm->def->name, uuidstr);
> +            virObjectUnlock(vm);
> +            vm = NULL;

These two lines should go to 4/13.

>              goto cleanup;
>          }
>  
> @@ -1908,6 +1921,8 @@ virDomainObjPtr virDomainObjListAdd(virDomainObjListPtr doms,
>                  virReportError(VIR_ERR_OPERATION_INVALID,
>                                 _("domain is already active as '%s'"),
>                                 vm->def->name);
> +                virObjectUnlock(vm);
> +                vm = NULL;
>                  goto cleanup;
>              }
>          }

And this hunk should go to 4/13 too.

> @@ -1934,12 +1949,11 @@ virDomainObjPtr virDomainObjListAdd(virDomainObjListPtr doms,
>          }
>      } else {
>          /* UUID does not match, but if a name matches, refuse it */
> -        if ((vm = virDomainObjListFindByName(doms, def->name))) {
> +        if ((vm = virHashSearch(doms->objs, virDomainObjListSearchName, def->name))) {

I believe you wanted to add virObjectLock(vm) here rather than...

>              virUUIDFormat(vm->def->uuid, uuidstr);
>              virReportError(VIR_ERR_OPERATION_FAILED,
>                             _("domain '%s' already exists with uuid %s"),
>                             def->name, uuidstr);
> -            virObjectUnlock(vm);

...removing this unlock here.

>              vm = NULL;
>              goto cleanup;
>          }
...

Jirka