On 07/30/2015 06:25 PM, Daniel P. Berrange wrote:
On Thu, Jul 23, 2015 at 06:13:49PM +0800, Luyao Huang wrote:
Signed-off-by: Luyao Huang <lhuang@redhat.com> --- src/qemu/qemu_conf.h | 3 + src/qemu/qemu_driver.c | 4 ++ src/qemu/qemu_process.c | 158 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 165 insertions(+)
+static int +qemuPrepareShmemDevice(virQEMUDriverPtr driver, + virDomainObjPtr vm, + virDomainShmemDefPtr shmem) +{ + int ret = -1; + virShmObjectPtr tmp; + virShmObjectListPtr list = driver->shmlist; + bool othercreate = false; + char *path = NULL; + bool teardownlabel = false; + bool teardownshm = false; + int type, fd; + + virObjectLock(list); + + if ((tmp = virShmObjectFindByName(list, shmem->name))) { + if (shmem->size > tmp->size) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("Shmem object %s is already exists and " + "size is smaller than require size"), + tmp->name); + goto cleanup; + } + + if (virShmSetUsedDomain(tmp, QEMU_DRIVER_NAME, vm->def->name) < 0) + goto cleanup; + + if (virShmObjectSaveState(tmp, list->stateDir) < 0) + goto cleanup; + + virObjectUnlock(list); + return 0; + } + + if (!shmem->server.enabled) { + if ((fd = virShmCreate(shmem->name, shmem->size, false, &othercreate, 0600)) < 0) + goto cleanup; + VIR_FORCE_CLOSE(fd); + + if ((ret = virShmBuildPath(shmem->name, &path)) == -1) { + ignore_value(virShmUnlink(shmem->name)); + goto cleanup; + } else if (ret == -2 && !othercreate) { + ignore_value(virShmUnlink(shmem->name)); Why are you treating -1 differentl from -2 - in both cases we should abort creation as that indicates the method either failed or is not supported in this platform.
What i thought when i wrote this is : when ret = -2 this means we do not support virShmBuildPath in that platform (this could only happened on some other platform which support shm_open/shm_unlink ,just like solaris, freebsd) but we could use shm_open, on that platform the shm obj is not in /dev/shm or not exist in the file system, if we help to create that shm obj but cannot find a way to relabel it, qemu will cannot use the shm in that case, so unlink the shm and let qemu create it will make guest can start success, and we could unlink the qemu create shm obj if there is no guest use it. I am not sure this is a good idea right now, since i am not sure this will work as except on different platform. Maybe i should remove it and make virShmBuildPath return -1 if not support on that platform.
Regards, Daniel
Luyao