1 files changed, 106 insertions, 35 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 7b69b8d0313d..66a416b42c18 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -243,6 +243,11 @@ static int notify_on_release(const struct cgroup *cgrp)
 	return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
 }
 
+static int clone_children(const struct cgroup *cgrp)
+{
+	return test_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+}
+
 /*
  * for_each_subsys() allows you to iterate on each subsystem attached to
  * an active hierarchy
@@ -777,6 +782,7 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb)
 	struct inode *inode = new_inode(sb);
 
 	if (inode) {
+		inode->i_ino = get_next_ino();
 		inode->i_mode = mode;
 		inode->i_uid = current_fsuid();
 		inode->i_gid = current_fsgid();
@@ -1039,6 +1045,8 @@ static int cgroup_show_options(struct seq_file *seq, struct vfsmount *vfs)
 		seq_puts(seq, ",noprefix");
 	if (strlen(root->release_agent_path))
 		seq_printf(seq, ",release_agent=%s", root->release_agent_path);
+	if (clone_children(&root->top_cgroup))
+		seq_puts(seq, ",clone_children");
 	if (strlen(root->name))
 		seq_printf(seq, ",name=%s", root->name);
 	mutex_unlock(&cgroup_mutex);
@@ -1049,6 +1057,7 @@ struct cgroup_sb_opts {
 	unsigned long subsys_bits;
 	unsigned long flags;
 	char *release_agent;
+	bool clone_children;
 	char *name;
 	/* User explicitly requested empty subsystem */
 	bool none;
@@ -1065,7 +1074,8 @@ struct cgroup_sb_opts {
  */
 static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 {
-	char *token, *o = data ?: "all";
+	char *token, *o = data;
+	bool all_ss = false, one_ss = false;
 	unsigned long mask = (unsigned long)-1;
 	int i;
 	bool module_pin_failed = false;
@@ -1081,22 +1091,27 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 	while ((token = strsep(&o, ",")) != NULL) {
 		if (!*token)
 			return -EINVAL;
-		if (!strcmp(token, "all")) {
-			/* Add all non-disabled subsystems */
-			opts->subsys_bits = 0;
-			for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
-				struct cgroup_subsys *ss = subsys[i];
-				if (ss == NULL)
-					continue;
-				if (!ss->disabled)
-					opts->subsys_bits |= 1ul << i;
-			}
-		} else if (!strcmp(token, "none")) {
+		if (!strcmp(token, "none")) {
 			/* Explicitly have no subsystems */
 			opts->none = true;
-		} else if (!strcmp(token, "noprefix")) {
+			continue;
+		}
+		if (!strcmp(token, "all")) {
+			/* Mutually exclusive option 'all' + subsystem name */
+			if (one_ss)
+				return -EINVAL;
+			all_ss = true;
+			continue;
+		}
+		if (!strcmp(token, "noprefix")) {
 			set_bit(ROOT_NOPREFIX, &opts->flags);
-		} else if (!strncmp(token, "release_agent=", 14)) {
+			continue;
+		}
+		if (!strcmp(token, "clone_children")) {
+			opts->clone_children = true;
+			continue;
+		}
+		if (!strncmp(token, "release_agent=", 14)) {
 			/* Specifying two release agents is forbidden */
 			if (opts->release_agent)
 				return -EINVAL;
@@ -1104,7 +1119,9 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 				kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
 			if (!opts->release_agent)
 				return -ENOMEM;
-		} else if (!strncmp(token, "name=", 5)) {
+			continue;
+		}
+		if (!strncmp(token, "name=", 5)) {
 			const char *name = token + 5;
 			/* Can't specify an empty name */
 			if (!strlen(name))
@@ -1126,20 +1143,44 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
 					      GFP_KERNEL);
 			if (!opts->name)
 				return -ENOMEM;
-		} else {
-			struct cgroup_subsys *ss;
-			for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
-				ss = subsys[i];
-				if (ss == NULL)
-					continue;
-				if (!strcmp(token, ss->name)) {
-					if (!ss->disabled)
-						set_bit(i, &opts->subsys_bits);
-					break;
-				}
-			}
-			if (i == CGROUP_SUBSYS_COUNT)
-				return -ENOENT;
+
+			continue;
+		}
+
+		for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+			struct cgroup_subsys *ss = subsys[i];
+			if (ss == NULL)
+				continue;
+			if (strcmp(token, ss->name))
+				continue;
+			if (ss->disabled)
+				continue;
+
+			/* Mutually exclusive option 'all' + subsystem name */
+			if (all_ss)
+				return -EINVAL;
+			set_bit(i, &opts->subsys_bits);
+			one_ss = true;
+
+			break;
+		}
+		if (i == CGROUP_SUBSYS_COUNT)
+			return -ENOENT;
+	}
+
+	/*
+	 * If the 'all' option was specified select all the subsystems,
+	 * otherwise 'all, 'none' and a subsystem name options were not
+	 * specified, let's default to 'all'
+	 */
+	if (all_ss || (!all_ss && !one_ss && !opts->none)) {
+		for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
+			struct cgroup_subsys *ss = subsys[i];
+			if (ss == NULL)
+				continue;
+			if (ss->disabled)
+				continue;
+			set_bit(i, &opts->subsys_bits);
 		}
 	}
 
@@ -1354,6 +1395,8 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
 		strcpy(root->release_agent_path, opts->release_agent);
 	if (opts->name)
 		strcpy(root->name, opts->name);
+	if (opts->clone_children)
+		set_bit(CGRP_CLONE_CHILDREN, &root->top_cgroup.flags);
 	return root;
 }
 
@@ -1417,9 +1460,9 @@ static int cgroup_get_rootdir(struct super_block *sb)
 	return 0;
 }
 
-static int cgroup_get_sb(struct file_system_type *fs_type,
+static struct dentry *cgroup_mount(struct file_system_type *fs_type,
 			 int flags, const char *unused_dev_name,
-			 void *data, struct vfsmount *mnt)
+			 void *data)
 {
 	struct cgroup_sb_opts opts;
 	struct cgroupfs_root *root;
@@ -1553,10 +1596,9 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
 		drop_parsed_module_refcounts(opts.subsys_bits);
 	}
 
-	simple_set_mnt(mnt, sb);
 	kfree(opts.release_agent);
 	kfree(opts.name);
-	return 0;
+	return dget(sb->s_root);
 
  drop_new_super:
 	deactivate_locked_super(sb);
@@ -1565,7 +1607,7 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
  out_err:
 	kfree(opts.release_agent);
 	kfree(opts.name);
-	return ret;
+	return ERR_PTR(ret);
 }
 
 static void cgroup_kill_sb(struct super_block *sb) {
@@ -1615,7 +1657,7 @@ static void cgroup_kill_sb(struct super_block *sb) {
 
 static struct file_system_type cgroup_fs_type = {
 	.name = "cgroup",
-	.get_sb = cgroup_get_sb,
+	.mount = cgroup_mount,
 	.kill_sb = cgroup_kill_sb,
 };
 
@@ -1879,6 +1921,8 @@ static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
 				      const char *buffer)
 {
 	BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
+	if (strlen(buffer) >= PATH_MAX)
+		return -EINVAL;
 	if (!cgroup_lock_live_group(cgrp))
 		return -ENODEV;
 	strcpy(cgrp->root->release_agent_path, buffer);
@@ -3172,6 +3216,23 @@ fail:
 	return ret;
 }
 
+static u64 cgroup_clone_children_read(struct cgroup *cgrp,
+				    struct cftype *cft)
+{
+	return clone_children(cgrp);
+}
+
+static int cgroup_clone_children_write(struct cgroup *cgrp,
+				     struct cftype *cft,
+				     u64 val)
+{
+	if (val)
+		set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+	else
+		clear_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+	return 0;
+}
+
 /*
  * for the common functions, 'private' gives the type of file
  */
@@ -3202,6 +3263,11 @@ static struct cftype files[] = {
 		.write_string = cgroup_write_event_control,
 		.mode = S_IWUGO,
 	},
+	{
+		.name = "cgroup.clone_children",
+		.read_u64 = cgroup_clone_children_read,
+		.write_u64 = cgroup_clone_children_write,
+	},
 };
 
 static struct cftype cft_release_agent = {
@@ -3331,6 +3397,9 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 	if (notify_on_release(parent))
 		set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
 
+	if (clone_children(parent))
+		set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
+
 	for_each_subsys(root, ss) {
 		struct cgroup_subsys_state *css = ss->create(ss, cgrp);
 
@@ -3345,6 +3414,8 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 				goto err_destroy;
 		}
 		/* At error, ->destroy() callback has to free assigned ID. */
+		if (clone_children(parent) && ss->post_clone)
+			ss->post_clone(ss, cgrp);
 	}
 
 	cgroup_lock_hierarchy(root);