From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Store the results in cgroup_fs_context. There's a nasty twist caused
by the enabling/disabling subsystems - we can't do the checks sensitive
to that until cgroup_mutex gets grabbed. Frankly, these checks are
complete bullshit (e.g. all,none combination is accepted if all subsystems
are disabled; so's cpusets,none and all,cpusets when cpusets is disabled,
etc.), but touching that would be a userland-visible behaviour change ;-/
So we do parsing in ->parse_monolithic() and have the consistency checks
done in check_cgroupfs_options(), with the latter called (on already parsed
options) from cgroup1_get_tree() and cgroup1_reconfigure().
Freeing the strdup'ed strings is done from fs_context destructor, which
somewhat simplifies the life for cgroup1_{get_tree,reconfigure}().
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
kernel/cgroup/cgroup-internal.h | 23 +++---
kernel/cgroup/cgroup-v1.c | 143 ++++++++++++++++++---------------------
kernel/cgroup/cgroup.c | 54 +++++++--------
3 files changed, 104 insertions(+), 116 deletions(-)
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 37836d598ff8..e627ff193dba 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -41,7 +41,15 @@ extern void __init enable_debug_cgroup(void);
* The cgroup filesystem superblock creation/mount context.
*/
struct cgroup_fs_context {
- char *data;
+ unsigned int flags; /* CGRP_ROOT_* flags */
+
+ /* cgroup1 bits */
+ bool cpuset_clone_children;
+ bool none; /* User explicitly requested empty subsystem */
+ bool all_ss; /* Seen 'all' option */
+ u16 subsys_mask; /* Selected subsystems */
+ char *name; /* Hierarchy name */
+ char *release_agent; /* Path for release notifications */
};
static inline struct cgroup_fs_context *cgroup_fc2context(struct fs_context *fc)
@@ -130,16 +138,6 @@ struct cgroup_mgctx {
#define DEFINE_CGROUP_MGCTX(name) \
struct cgroup_mgctx name = CGROUP_MGCTX_INIT(name)
-struct cgroup_sb_opts {
- u16 subsys_mask;
- unsigned int flags;
- char *release_agent;
- bool cpuset_clone_children;
- char *name;
- /* User explicitly requested empty subsystem */
- bool none;
-};
-
extern struct mutex cgroup_mutex;
extern spinlock_t css_set_lock;
extern struct cgroup_subsys *cgroup_subsys[];
@@ -210,7 +208,7 @@ int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
struct cgroup_namespace *ns);
void cgroup_free_root(struct cgroup_root *root);
-void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts);
+void init_cgroup_root(struct cgroup_root *root, struct cgroup_fs_context *ctx);
int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask);
int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask);
struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
@@ -266,6 +264,7 @@ void cgroup1_pidlist_destroy_all(struct cgroup *cgrp);
void cgroup1_release_agent(struct work_struct *work);
void cgroup1_check_for_release(struct cgroup *cgrp);
int cgroup1_get_tree(struct fs_context *fc);
+int parse_cgroup1_options(char *data, struct cgroup_fs_context *ctx);
int cgroup1_reconfigure(struct fs_context *ctx);
#endif /* __CGROUP_INTERNAL_H */
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index 7ae3810dcbdf..5c93643090e9 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -906,61 +906,47 @@ static int cgroup1_show_options(struct seq_file *seq, struct kernfs_root *kf_roo
return 0;
}
-static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
+int parse_cgroup1_options(char *data, struct cgroup_fs_context *ctx)
{
char *token, *o = data;
- bool all_ss = false, one_ss = false;
- u16 mask = U16_MAX;
struct cgroup_subsys *ss;
- int nr_opts = 0;
int i;
-#ifdef CONFIG_CPUSETS
- mask = ~((u16)1 << cpuset_cgrp_id);
-#endif
-
- memset(opts, 0, sizeof(*opts));
-
while ((token = strsep(&o, ",")) != NULL) {
- nr_opts++;
-
if (!*token)
return -EINVAL;
if (!strcmp(token, "none")) {
/* Explicitly have no subsystems */
- opts->none = true;
+ ctx->none = true;
continue;
}
if (!strcmp(token, "all")) {
- /* Mutually exclusive option 'all' + subsystem name */
- if (one_ss)
- return -EINVAL;
- all_ss = true;
+ ctx->all_ss = true;
continue;
}
if (!strcmp(token, "noprefix")) {
- opts->flags |= CGRP_ROOT_NOPREFIX;
+ ctx->flags |= CGRP_ROOT_NOPREFIX;
continue;
}
if (!strcmp(token, "clone_children")) {
- opts->cpuset_clone_children = true;
+ ctx->cpuset_clone_children = true;
continue;
}
if (!strcmp(token, "cpuset_v2_mode")) {
- opts->flags |= CGRP_ROOT_CPUSET_V2_MODE;
+ ctx->flags |= CGRP_ROOT_CPUSET_V2_MODE;
continue;
}
if (!strcmp(token, "xattr")) {
- opts->flags |= CGRP_ROOT_XATTR;
+ ctx->flags |= CGRP_ROOT_XATTR;
continue;
}
if (!strncmp(token, "release_agent=", 14)) {
/* Specifying two release agents is forbidden */
- if (opts->release_agent)
+ if (ctx->release_agent)
return -EINVAL;
- opts->release_agent =
+ ctx->release_agent =
kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
- if (!opts->release_agent)
+ if (!ctx->release_agent)
return -ENOMEM;
continue;
}
@@ -983,12 +969,12 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
return -EINVAL;
}
/* Specifying two names is forbidden */
- if (opts->name)
+ if (ctx->name)
return -EINVAL;
- opts->name = kstrndup(name,
+ ctx->name = kstrndup(name,
MAX_CGROUP_ROOT_NAMELEN - 1,
GFP_KERNEL);
- if (!opts->name)
+ if (!ctx->name)
return -ENOMEM;
continue;
@@ -997,38 +983,51 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
for_each_subsys(ss, i) {
if (strcmp(token, ss->legacy_name))
continue;
- if (!cgroup_ssid_enabled(i))
- continue;
- if (cgroup1_ssid_disabled(i))
- continue;
-
- /* Mutually exclusive option 'all' + subsystem name */
- if (all_ss)
- return -EINVAL;
- opts->subsys_mask |= (1 << i);
- one_ss = true;
-
+ ctx->subsys_mask |= (1 << i);
break;
}
if (i == CGROUP_SUBSYS_COUNT)
return -ENOENT;
}
+ return 0;
+}
+
+static int check_cgroupfs_options(struct cgroup_fs_context *ctx)
+{
+ u16 mask = U16_MAX;
+ u16 enabled = 0;
+ struct cgroup_subsys *ss;
+ int i;
+
+#ifdef CONFIG_CPUSETS
+ mask = ~((u16)1 << cpuset_cgrp_id);
+#endif
+ for_each_subsys(ss, i)
+ if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
+ enabled |= 1 << i;
+
+ ctx->subsys_mask &= enabled;
/*
- * If the 'all' option was specified select all the subsystems,
- * otherwise if 'none', 'name=' and a subsystem name options were
- * not specified, let's default to 'all'
+ * In absense of 'none', 'name=' or subsystem name options,
+ * let's default to 'all'.
*/
- if (all_ss || (!one_ss && !opts->none && !opts->name))
- for_each_subsys(ss, i)
- if (cgroup_ssid_enabled(i) && !cgroup1_ssid_disabled(i))
- opts->subsys_mask |= (1 << i);
+ if (!ctx->subsys_mask && !ctx->none && !ctx->name)
+ ctx->all_ss = true;
+
+ if (ctx->all_ss) {
+ /* Mutually exclusive option 'all' + subsystem name */
+ if (ctx->subsys_mask)
+ return -EINVAL;
+ /* 'all' => select all the subsystems */
+ ctx->subsys_mask = enabled;
+ }
/*
* We either have to specify by name or by subsystems. (So all
* empty hierarchies must have a name).
*/
- if (!opts->subsys_mask && !opts->name)
+ if (!ctx->subsys_mask && !ctx->name)
return -EINVAL;
/*
@@ -1036,11 +1035,11 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
* with the old cpuset, so we allow noprefix only if mounting just
* the cpuset subsystem.
*/
- if ((opts->flags & CGRP_ROOT_NOPREFIX) && (opts->subsys_mask & mask))
+ if ((ctx->flags & CGRP_ROOT_NOPREFIX) && (ctx->subsys_mask & mask))
return -EINVAL;
/* Can't specify "none" and some subsystems */
- if (opts->subsys_mask && opts->none)
+ if (ctx->subsys_mask && ctx->none)
return -EINVAL;
return 0;
@@ -1052,28 +1051,27 @@ int cgroup1_reconfigure(struct fs_context *fc)
struct kernfs_root *kf_root = kernfs_root_from_sb(fc->root->d_sb);
struct cgroup_root *root = cgroup_root_from_kf(kf_root);
int ret = 0;
- struct cgroup_sb_opts opts;
u16 added_mask, removed_mask;
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* See what subsystems are wanted */
- ret = parse_cgroupfs_options(ctx->data, &opts);
+ ret = check_cgroupfs_options(ctx);
if (ret)
goto out_unlock;
- if (opts.subsys_mask != root->subsys_mask || opts.release_agent)
+ if (ctx->subsys_mask != root->subsys_mask || ctx->release_agent)
pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n",
task_tgid_nr(current), current->comm);
- added_mask = opts.subsys_mask & ~root->subsys_mask;
- removed_mask = root->subsys_mask & ~opts.subsys_mask;
+ added_mask = ctx->subsys_mask & ~root->subsys_mask;
+ removed_mask = root->subsys_mask & ~ctx->subsys_mask;
/* Don't allow flags or name to change at remount */
- if ((opts.flags ^ root->flags) ||
- (opts.name && strcmp(opts.name, root->name))) {
+ if ((ctx->flags ^ root->flags) ||
+ (ctx->name && strcmp(ctx->name, root->name))) {
pr_err("option or name mismatch, new: 0x%x \"%s\", old: 0x%x \"%s\"\n",
- opts.flags, opts.name ?: "", root->flags, root->name);
+ ctx->flags, ctx->name ?: "", root->flags, root->name);
ret = -EINVAL;
goto out_unlock;
}
@@ -1090,17 +1088,15 @@ int cgroup1_reconfigure(struct fs_context *fc)
WARN_ON(rebind_subsystems(&cgrp_dfl_root, removed_mask));
- if (opts.release_agent) {
+ if (ctx->release_agent) {
spin_lock(&release_agent_path_lock);
- strcpy(root->release_agent_path, opts.release_agent);
+ strcpy(root->release_agent_path, ctx->release_agent);
spin_unlock(&release_agent_path_lock);
}
trace_cgroup_remount(root);
out_unlock:
- kfree(opts.release_agent);
- kfree(opts.name);
mutex_unlock(&cgroup_mutex);
return ret;
}
@@ -1117,7 +1113,6 @@ int cgroup1_get_tree(struct fs_context *fc)
{
struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
- struct cgroup_sb_opts opts;
struct cgroup_root *root;
struct cgroup_subsys *ss;
struct dentry *dentry;
@@ -1130,7 +1125,7 @@ int cgroup1_get_tree(struct fs_context *fc)
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
/* First find the desired set of subsystems */
- ret = parse_cgroupfs_options(ctx->data, &opts);
+ ret = check_cgroupfs_options(ctx);
if (ret)
goto out_unlock;
@@ -1142,7 +1137,7 @@ int cgroup1_get_tree(struct fs_context *fc)
* starting. Testing ref liveliness is good enough.
*/
for_each_subsys(ss, i) {
- if (!(opts.subsys_mask & (1 << i)) ||
+ if (!(ctx->subsys_mask & (1 << i)) ||
ss->root == &cgrp_dfl_root)
continue;
@@ -1166,8 +1161,8 @@ int cgroup1_get_tree(struct fs_context *fc)
* name matches but sybsys_mask doesn't, we should fail.
* Remember whether name matched.
*/
- if (opts.name) {
- if (strcmp(opts.name, root->name))
+ if (ctx->name) {
+ if (strcmp(ctx->name, root->name))
continue;
name_match = true;
}
@@ -1176,15 +1171,15 @@ int cgroup1_get_tree(struct fs_context *fc)
* If we asked for subsystems (or explicitly for no
* subsystems) then they must match.
*/
- if ((opts.subsys_mask || opts.none) &&
- (opts.subsys_mask != root->subsys_mask)) {
+ if ((ctx->subsys_mask || ctx->none) &&
+ (ctx->subsys_mask != root->subsys_mask)) {
if (!name_match)
continue;
ret = -EBUSY;
goto out_unlock;
}
- if (root->flags ^ opts.flags)
+ if (root->flags ^ ctx->flags)
pr_warn("new mount options do not match the existing superblock, will be ignored\n");
ret = 0;
@@ -1196,7 +1191,7 @@ int cgroup1_get_tree(struct fs_context *fc)
* specification is allowed for already existing hierarchies but we
* can't create new one without subsys specification.
*/
- if (!opts.subsys_mask && !opts.none) {
+ if (!ctx->subsys_mask && !ctx->none) {
ret = -EINVAL;
goto out_unlock;
}
@@ -1213,9 +1208,9 @@ int cgroup1_get_tree(struct fs_context *fc)
goto out_unlock;
}
- init_cgroup_root(root, &opts);
+ init_cgroup_root(root, ctx);
- ret = cgroup_setup_root(root, opts.subsys_mask);
+ ret = cgroup_setup_root(root, ctx->subsys_mask);
if (ret)
cgroup_free_root(root);
@@ -1223,14 +1218,10 @@ int cgroup1_get_tree(struct fs_context *fc)
if (!ret && !percpu_ref_tryget_live(&root->cgrp.self.refcnt)) {
mutex_unlock(&cgroup_mutex);
msleep(10);
- ret = restart_syscall();
- goto out_free;
+ return restart_syscall();
}
mutex_unlock(&cgroup_mutex);
out_free:
- kfree(opts.release_agent);
- kfree(opts.name);
-
if (ret)
return ret;
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 0652f74064a2..33da9eef3ef4 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -1814,14 +1814,8 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root
static int cgroup_reconfigure(struct fs_context *fc)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
- unsigned int root_flags;
- int ret;
-
- ret = parse_cgroup_root_flags(ctx->data, &root_flags);
- if (ret)
- return ret;
- apply_cgroup_root_flags(root_flags);
+ apply_cgroup_root_flags(ctx->flags);
return 0;
}
@@ -1909,7 +1903,7 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
INIT_WORK(&cgrp->release_agent_work, cgroup1_release_agent);
}
-void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
+void init_cgroup_root(struct cgroup_root *root, struct cgroup_fs_context *ctx)
{
struct cgroup *cgrp = &root->cgrp;
@@ -1919,12 +1913,12 @@ void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
init_cgroup_housekeeping(cgrp);
idr_init(&root->cgroup_idr);
- root->flags = opts->flags;
- if (opts->release_agent)
- strscpy(root->release_agent_path, opts->release_agent, PATH_MAX);
- if (opts->name)
- strscpy(root->name, opts->name, MAX_CGROUP_ROOT_NAMELEN);
- if (opts->cpuset_clone_children)
+ root->flags = ctx->flags;
+ if (ctx->release_agent)
+ strscpy(root->release_agent_path, ctx->release_agent, PATH_MAX);
+ if (ctx->name)
+ strscpy(root->name, ctx->name, MAX_CGROUP_ROOT_NAMELEN);
+ if (ctx->cpuset_clone_children)
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
}
@@ -2075,6 +2069,8 @@ static void cgroup_fs_context_free(struct fs_context *fc)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+ kfree(ctx->name);
+ kfree(ctx->release_agent);
kfree(ctx);
}
@@ -2082,28 +2078,30 @@ static int cgroup_parse_monolithic(struct fs_context *fc, void *data)
{
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
- ctx->data = data;
- if (ctx->data)
- security_sb_eat_lsm_opts(ctx->data, &fc->security);
- return 0;
+ if (data)
+ security_sb_eat_lsm_opts(data, &fc->security);
+ return parse_cgroup_root_flags(data, &ctx->flags);
+}
+
+static int cgroup1_parse_monolithic(struct fs_context *fc, void *data)
+{
+ struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+
+ if (data)
+ security_sb_eat_lsm_opts(data, &fc->security);
+ return parse_cgroup1_options(data, ctx);
}
static int cgroup_get_tree(struct fs_context *fc)
{
struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
- unsigned int root_flags;
struct dentry *root;
- int ret;
/* Check if the caller has permission to mount. */
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
- ret = parse_cgroup_root_flags(ctx->data, &root_flags);
- if (ret)
- return ret;
-
cgrp_dfl_visible = true;
cgroup_get_live(&cgrp_dfl_root.cgrp);
@@ -2112,7 +2110,7 @@ static int cgroup_get_tree(struct fs_context *fc)
if (IS_ERR(root))
return PTR_ERR(root);
- apply_cgroup_root_flags(root_flags);
+ apply_cgroup_root_flags(ctx->flags);
fc->root = root;
return 0;
}
@@ -2126,7 +2124,7 @@ static const struct fs_context_operations cgroup_fs_context_ops = {
static const struct fs_context_operations cgroup1_fs_context_ops = {
.free = cgroup_fs_context_free,
- .parse_monolithic = cgroup_parse_monolithic,
+ .parse_monolithic = cgroup1_parse_monolithic,
.get_tree = cgroup1_get_tree,
.reconfigure = cgroup1_reconfigure,
};
@@ -5376,11 +5374,11 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
*/
int __init cgroup_init_early(void)
{
- static struct cgroup_sb_opts __initdata opts;
+ static struct cgroup_fs_context __initdata ctx;
struct cgroup_subsys *ss;
int i;
- init_cgroup_root(&cgrp_dfl_root, &opts);
+ init_cgroup_root(&cgrp_dfl_root, &ctx);
cgrp_dfl_root.cgrp.self.flags |= CSS_NO_REF;
RCU_INIT_POINTER(init_task.cgroups, &init_css_set);
