*/
#include <linux/cgroup.h>
+#include <linux/ctype.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/cgroup_subsys.h>
};
+#define MAX_CGROUP_ROOT_NAMELEN 64
+
/*
* A cgroupfs_root represents the root of a cgroup hierarchy,
* and may be associated with a superblock to form an active
/* The path to use for release notifications. */
char release_agent_path[PATH_MAX];
+
+ /* The name for this hierarchy - may be empty */
+ char name[MAX_CGROUP_ROOT_NAMELEN];
};
/*
static int cgroup_mkdir(struct inode *dir, struct dentry *dentry, int mode);
static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry);
static int cgroup_populate_dir(struct cgroup *cgrp);
-static struct inode_operations cgroup_dir_inode_operations;
+static const struct inode_operations cgroup_dir_inode_operations;
static struct file_operations proc_cgroupstats_operations;
static struct backing_dev_info cgroup_backing_dev_info = {
seq_puts(seq, ",noprefix");
if (strlen(root->release_agent_path))
seq_printf(seq, ",release_agent=%s", root->release_agent_path);
+ if (strlen(root->name))
+ seq_printf(seq, ",name=%s", root->name);
mutex_unlock(&cgroup_mutex);
return 0;
}
unsigned long subsys_bits;
unsigned long flags;
char *release_agent;
+ char *name;
+
+ struct cgroupfs_root *new_root;
};
/* Convert a hierarchy specifier into a bitmask of subsystems and
mask = ~(1UL << cpuset_subsys_id);
#endif
- opts->subsys_bits = 0;
- opts->flags = 0;
- opts->release_agent = NULL;
+ memset(opts, 0, sizeof(*opts));
while ((token = strsep(&o, ",")) != NULL) {
if (!*token)
/* Specifying two release agents is forbidden */
if (opts->release_agent)
return -EINVAL;
- opts->release_agent = kzalloc(PATH_MAX, GFP_KERNEL);
+ opts->release_agent =
+ kstrndup(token + 14, PATH_MAX, GFP_KERNEL);
if (!opts->release_agent)
return -ENOMEM;
- strncpy(opts->release_agent, token + 14, PATH_MAX - 1);
- opts->release_agent[PATH_MAX - 1] = 0;
+ } else if (!strncmp(token, "name=", 5)) {
+ int i;
+ const char *name = token + 5;
+ /* Can't specify an empty name */
+ if (!strlen(name))
+ return -EINVAL;
+ /* Must match [\w.-]+ */
+ for (i = 0; i < strlen(name); i++) {
+ char c = name[i];
+ if (isalnum(c))
+ continue;
+ if ((c == '.') || (c == '-') || (c == '_'))
+ continue;
+ return -EINVAL;
+ }
+ /* Specifying two names is forbidden */
+ if (opts->name)
+ return -EINVAL;
+ opts->name = kstrndup(name,
+ MAX_CGROUP_ROOT_NAMELEN,
+ GFP_KERNEL);
+ if (!opts->name)
+ return -ENOMEM;
} else {
struct cgroup_subsys *ss;
int i;
return -EINVAL;
/* We can't have an empty hierarchy */
- if (!opts->subsys_bits)
+ if (!opts->subsys_bits && !opts->name)
return -EINVAL;
return 0;
goto out_unlock;
}
+ /* Don't allow name to change at remount */
+ if (opts.name && strcmp(opts.name, root->name)) {
+ ret = -EINVAL;
+ goto out_unlock;
+ }
+
ret = rebind_subsystems(root, opts.subsys_bits);
if (ret)
goto out_unlock;
strcpy(root->release_agent_path, opts.release_agent);
out_unlock:
kfree(opts.release_agent);
+ kfree(opts.name);
mutex_unlock(&cgroup_mutex);
mutex_unlock(&cgrp->dentry->d_inode->i_mutex);
unlock_kernel();
INIT_LIST_HEAD(&cgrp->pids_list);
init_rwsem(&cgrp->pids_mutex);
}
+
static void init_cgroup_root(struct cgroupfs_root *root)
{
struct cgroup *cgrp = &root->top_cgroup;
static int cgroup_test_super(struct super_block *sb, void *data)
{
- struct cgroupfs_root *new = data;
+ struct cgroup_sb_opts *opts = data;
struct cgroupfs_root *root = sb->s_fs_info;
- /* First check subsystems */
- if (new->subsys_bits != root->subsys_bits)
- return 0;
+ /* If we asked for a name then it must match */
+ if (opts->name && strcmp(opts->name, root->name))
+ return 0;
- /* Next check flags */
- if (new->flags != root->flags)
+ /* If we asked for subsystems then they must match */
+ if (opts->subsys_bits && (opts->subsys_bits != root->subsys_bits))
return 0;
return 1;
}
+static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
+{
+ struct cgroupfs_root *root;
+
+ /* Empty hierarchies aren't supported */
+ if (!opts->subsys_bits)
+ return NULL;
+
+ root = kzalloc(sizeof(*root), GFP_KERNEL);
+ if (!root)
+ return ERR_PTR(-ENOMEM);
+
+ init_cgroup_root(root);
+ root->subsys_bits = opts->subsys_bits;
+ root->flags = opts->flags;
+ if (opts->release_agent)
+ strcpy(root->release_agent_path, opts->release_agent);
+ if (opts->name)
+ strcpy(root->name, opts->name);
+ return root;
+}
+
static int cgroup_set_super(struct super_block *sb, void *data)
{
int ret;
- struct cgroupfs_root *root = data;
+ struct cgroup_sb_opts *opts = data;
+
+ /* If we don't have a new root, we can't set up a new sb */
+ if (!opts->new_root)
+ return -EINVAL;
+
+ BUG_ON(!opts->subsys_bits);
ret = set_anon_super(sb, NULL);
if (ret)
return ret;
- sb->s_fs_info = root;
- root->sb = sb;
+ sb->s_fs_info = opts->new_root;
+ opts->new_root->sb = sb;
sb->s_blocksize = PAGE_CACHE_SIZE;
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
void *data, struct vfsmount *mnt)
{
struct cgroup_sb_opts opts;
+ struct cgroupfs_root *root;
int ret = 0;
struct super_block *sb;
- struct cgroupfs_root *root;
- struct list_head tmp_cg_links;
+ struct cgroupfs_root *new_root;
/* First find the desired set of subsystems */
ret = parse_cgroupfs_options(data, &opts);
- if (ret) {
- kfree(opts.release_agent);
- return ret;
- }
-
- root = kzalloc(sizeof(*root), GFP_KERNEL);
- if (!root) {
- kfree(opts.release_agent);
- return -ENOMEM;
- }
+ if (ret)
+ goto out_err;
- init_cgroup_root(root);
- root->subsys_bits = opts.subsys_bits;
- root->flags = opts.flags;
- if (opts.release_agent) {
- strcpy(root->release_agent_path, opts.release_agent);
- kfree(opts.release_agent);
+ /*
+ * Allocate a new cgroup root. We may not need it if we're
+ * reusing an existing hierarchy.
+ */
+ new_root = cgroup_root_from_opts(&opts);
+ if (IS_ERR(new_root)) {
+ ret = PTR_ERR(new_root);
+ goto out_err;
}
+ opts.new_root = new_root;
- sb = sget(fs_type, cgroup_test_super, cgroup_set_super, root);
-
+ /* Locate an existing or new sb for this hierarchy */
+ sb = sget(fs_type, cgroup_test_super, cgroup_set_super, &opts);
if (IS_ERR(sb)) {
- kfree(root);
- return PTR_ERR(sb);
+ ret = PTR_ERR(sb);
+ kfree(opts.new_root);
+ goto out_err;
}
- if (sb->s_fs_info != root) {
- /* Reusing an existing superblock */
- BUG_ON(sb->s_root == NULL);
- kfree(root);
- root = NULL;
- } else {
- /* New superblock */
+ root = sb->s_fs_info;
+ BUG_ON(!root);
+ if (root == opts.new_root) {
+ /* We used the new root structure, so this is a new hierarchy */
+ struct list_head tmp_cg_links;
struct cgroup *root_cgrp = &root->top_cgroup;
struct inode *inode;
+ struct cgroupfs_root *existing_root;
int i;
BUG_ON(sb->s_root != NULL);
mutex_lock(&inode->i_mutex);
mutex_lock(&cgroup_mutex);
+ if (strlen(root->name)) {
+ /* Check for name clashes with existing mounts */
+ for_each_active_root(existing_root) {
+ if (!strcmp(existing_root->name, root->name)) {
+ ret = -EBUSY;
+ mutex_unlock(&cgroup_mutex);
+ mutex_unlock(&inode->i_mutex);
+ goto drop_new_super;
+ }
+ }
+ }
+
/*
* We're accessing css_set_count without locking
* css_set_lock here, but that's OK - it can only be
if (ret == -EBUSY) {
mutex_unlock(&cgroup_mutex);
mutex_unlock(&inode->i_mutex);
- goto free_cg_links;
+ free_cg_links(&tmp_cg_links);
+ goto drop_new_super;
}
/* EBUSY should be the only error here */
BUG_ON(root->number_of_cgroups != 1);
cgroup_populate_dir(root_cgrp);
- mutex_unlock(&inode->i_mutex);
mutex_unlock(&cgroup_mutex);
+ mutex_unlock(&inode->i_mutex);
+ } else {
+ /*
+ * We re-used an existing hierarchy - the new root (if
+ * any) is not needed
+ */
+ kfree(opts.new_root);
}
simple_set_mnt(mnt, sb);
+ kfree(opts.release_agent);
+ kfree(opts.name);
return 0;
- free_cg_links:
- free_cg_links(&tmp_cg_links);
drop_new_super:
deactivate_locked_super(sb);
+ out_err:
+ kfree(opts.release_agent);
+ kfree(opts.name);
+
return ret;
}
.release = cgroup_file_release,
};
-static struct inode_operations cgroup_dir_inode_operations = {
+static const struct inode_operations cgroup_dir_inode_operations = {
.lookup = simple_lookup,
.mkdir = cgroup_mkdir,
.rmdir = cgroup_rmdir,
return seq_printf(s, "%d\n", *(int *)v);
}
-static struct seq_operations cgroup_tasks_seq_operations = {
+static const struct seq_operations cgroup_tasks_seq_operations = {
.start = cgroup_tasks_start,
.stop = cgroup_tasks_stop,
.next = cgroup_tasks_next,
seq_printf(m, "%lu:", root->subsys_bits);
for_each_subsys(root, ss)
seq_printf(m, "%s%s", count++ ? "," : "", ss->name);
+ if (strlen(root->name))
+ seq_printf(m, "%sname=%s", count ? "," : "",
+ root->name);
seq_putc(m, ':');
get_first_subsys(&root->top_cgroup, NULL, &subsys_id);
cgrp = task_cgroup(tsk, subsys_id);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff