Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[linux-2.6-block.git] / kernel / cgroup / cgroup.c

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 300b0c416341cd03315b1072b8ad5fdaeb3df942..753afbca549fdaeba9c133c192c1927d1d9c6f3c 100644 (file)
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2201,8 +2201,7 @@ static int cgroup_init_fs_context(struct fs_context *fc)
                fc->ops = &cgroup_fs_context_ops;
        else
                fc->ops = &cgroup1_fs_context_ops;
-       if (fc->user_ns)
-               put_user_ns(fc->user_ns);
+       put_user_ns(fc->user_ns);
        fc->user_ns = get_user_ns(ctx->ns->user_ns);
        fc->global = true;
        return 0;
@@ -2243,6 +2242,50 @@ static struct file_system_type cgroup2_fs_type = {
        .fs_flags               = FS_USERNS_MOUNT,
 };
 
+#ifdef CONFIG_CPUSETS
+static const struct fs_context_operations cpuset_fs_context_ops = {
+       .get_tree       = cgroup1_get_tree,
+       .free           = cgroup_fs_context_free,
+};
+
+/*
+ * This is ugly, but preserves the userspace API for existing cpuset
+ * users. If someone tries to mount the "cpuset" filesystem, we
+ * silently switch it to mount "cgroup" instead
+ */
+static int cpuset_init_fs_context(struct fs_context *fc)
+{
+       char *agent = kstrdup("/sbin/cpuset_release_agent", GFP_USER);
+       struct cgroup_fs_context *ctx;
+       int err;
+
+       err = cgroup_init_fs_context(fc);
+       if (err) {
+               kfree(agent);
+               return err;
+       }
+
+       fc->ops = &cpuset_fs_context_ops;
+
+       ctx = cgroup_fc2context(fc);
+       ctx->subsys_mask = 1 << cpuset_cgrp_id;
+       ctx->flags |= CGRP_ROOT_NOPREFIX;
+       ctx->release_agent = agent;
+
+       get_filesystem(&cgroup_fs_type);
+       put_filesystem(fc->fs_type);
+       fc->fs_type = &cgroup_fs_type;
+
+       return 0;
+}
+
+static struct file_system_type cpuset_fs_type = {
+       .name                   = "cpuset",
+       .init_fs_context        = cpuset_init_fs_context,
+       .fs_flags               = FS_USERNS_MOUNT,
+};
+#endif
+
 int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
                          struct cgroup_namespace *ns)
 {
@@ -5761,6 +5804,9 @@ int __init cgroup_init(void)
        WARN_ON(register_filesystem(&cgroup_fs_type));
        WARN_ON(register_filesystem(&cgroup2_fs_type));
        WARN_ON(!proc_create_single("cgroups", 0, NULL, proc_cgroupstats_show));
+#ifdef CONFIG_CPUSETS
+       WARN_ON(register_filesystem(&cpuset_fs_type));
+#endif
 
        return 0;
 }