On Wed, Jan 29, 2014 at 12:02:44PM +0800, Li Zefan wrote: > On 2014/1/28 23:32, Tejun Heo wrote: > > cgroup_root_from_opts() checks whether (!opts->subsys_mask && > > !opts->none) and returns NULL if so. After that, if allocation fails, > > returns ERR_PTR(-ENOMEM). The caller, cgroup_mount(), doesn't treat > > NULL as an error but set opts.new_root to NULL; however, later on, > > cgroup_set_super() fails with -EINVAL if new_root is NULL. > > This patch changes mount semantics. > > If cgroup_root_from_opts() returns NULL, it means we should be looking > for existing superblock only. > > This will fail: > > # mount -t cgroup -o name=abc xxx /mnt > > But this is ok: > > # mount -t cgroup -o none,name=abc xxx /mnt > # mkdir /mnt/sub > # umount /mnt > # mount -t cgroup -o name=abc xxx /mnt <-- this won't work with your patch Ewwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww.... urgghhghghghhh............. Alright, dropping this patch and will update later patches to maintain the behavior. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
