[Devel] [PATCH RHEL7 v21 11/14] ve/cgroup: set release_agent_path for root cgroups separately for each ve.
Valeriy Vdovin
valeriy.vdovin at virtuozzo.com
Tue Jul 28 20:53:23 MSK 2020
This is done so that each container could set it's own release agent.
Release agent information is now stored in per-cgroup-root data
structure in ve.
https://jira.sw.ru/browse/PSBM-83887
Signed-off-by: Valeriy Vdovin <valeriy.vdovin at virtuozzo.com>
---
include/linux/cgroup.h | 3 --
include/linux/ve.h | 6 +++
kernel/cgroup.c | 100 ++++++++++++++++++++++++++++++++++++++++---------
kernel/ve/ve.c | 72 +++++++++++++++++++++++++++++++++++
4 files changed, 161 insertions(+), 20 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 5f1460d..fc138c0 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -429,9 +429,6 @@ struct cgroupfs_root {
/* IDs for cgroups in this hierarchy */
struct ida cgroup_ida;
- /* 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];
};
diff --git a/include/linux/ve.h b/include/linux/ve.h
index 65413d5..b6662637 100644
--- a/include/linux/ve.h
+++ b/include/linux/ve.h
@@ -214,6 +214,12 @@ void do_update_load_avg_ve(void);
void ve_add_to_release_list(struct cgroup *cgrp);
void ve_rm_from_release_list(struct cgroup *cgrp);
+
+int ve_set_release_agent_path(struct ve_struct *ve, struct cgroup *cgroot,
+ const char *release_agent);
+
+const char *ve_get_release_agent_path(struct cgroup *cgrp_root);
+
extern struct ve_struct *get_ve(struct ve_struct *ve);
extern void put_ve(struct ve_struct *ve);
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index aa93cf2..1d9c889 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1092,9 +1092,12 @@ static int rebind_subsystems(struct cgroupfs_root *root,
static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
{
+ const char *release_agent;
struct cgroupfs_root *root = dentry->d_sb->s_fs_info;
struct cgroup_subsys *ss;
+ struct cgroup *root_cgrp = &root->top_cgroup;
+ mutex_lock(&cgroup_mutex);
mutex_lock(&cgroup_root_mutex);
for_each_subsys(root, ss)
seq_printf(seq, ",%s", ss->name);
@@ -1106,14 +1109,37 @@ static int cgroup_show_options(struct seq_file *seq, struct dentry *dentry)
seq_puts(seq, ",xattr");
if (root->flags & CGRP_ROOT_CPUSET_V2_MODE)
seq_puts(seq, ",cpuset_v2_mode");
- if (strlen(root->release_agent_path))
- seq_show_option(seq, "release_agent",
- root->release_agent_path);
+#ifdef CONFIG_VE
+ {
+ struct ve_struct *ve = get_exec_env();
+
+ if (!ve_is_super(ve)) {
+ /*
+ * ve->init_task is NULL in case when cgroup is accessed
+ * before ve_start_container has been called.
+ *
+ * ve->init_task is synchronized via ve->ve_ns rcu, see
+ * ve_grab_context/drop_context.
+ */
+ rcu_read_lock();
+ if (ve->ve_ns)
+ root_cgrp = task_cgroup_from_root(ve->init_task,
+ root);
+ rcu_read_unlock();
+ }
+ }
+#endif
+ rcu_read_lock();
+ release_agent = ve_get_release_agent_path(root_cgrp);
+ if (release_agent && release_agent[0])
+ seq_show_option(seq, "release_agent", release_agent);
+ rcu_read_unlock();
if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->top_cgroup.flags))
seq_puts(seq, ",clone_children");
if (strlen(root->name))
seq_show_option(seq, "name", root->name);
mutex_unlock(&cgroup_root_mutex);
+ mutex_unlock(&cgroup_mutex);
return 0;
}
@@ -1386,8 +1412,13 @@ static int cgroup_remount(struct super_block *sb, int *flags, char *data)
/* re-populate subsystem files */
cgroup_populate_dir(cgrp, false, added_mask);
- if (opts.release_agent)
- strcpy(root->release_agent_path, opts.release_agent);
+ if (opts.release_agent) {
+ struct cgroup *root_cgrp;
+ root_cgrp = cgroup_get_local_root(cgrp);
+ if (root_cgrp->ve_owner)
+ ret = ve_set_release_agent_path(root_cgrp,
+ opts.release_agent);
+ }
out_unlock:
kfree(opts.release_agent);
kfree(opts.name);
@@ -1549,8 +1580,6 @@ static struct cgroupfs_root *cgroup_root_from_opts(struct cgroup_sb_opts *opts)
root->subsys_mask = opts->subsys_mask;
root->flags = opts->flags;
ida_init(&root->cgroup_ida);
- if (opts->release_agent)
- strcpy(root->release_agent_path, opts->release_agent);
if (opts->name)
strcpy(root->name, opts->name);
if (opts->cpuset_clone_children)
@@ -1748,6 +1777,11 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
cred = override_creds(&init_cred);
cgroup_populate_dir(root_cgrp, true, root->subsys_mask);
+ if (opts.release_agent) {
+ ret = ve_set_release_agent_path(root_cgrp,
+ opts.release_agent);
+ }
+
revert_creds(cred);
mutex_unlock(&cgroup_root_mutex);
mutex_unlock(&cgroup_mutex);
@@ -2317,7 +2351,8 @@ static int cgroup_procs_write(struct cgroup *cgrp, struct cftype *cft, u64 tgid)
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);
+ int ret = 0;
+ struct cgroup *root_cgrp;
if (strlen(buffer) >= PATH_MAX)
return -EINVAL;
@@ -2325,19 +2360,35 @@ static int cgroup_release_agent_write(struct cgroup *cgrp, struct cftype *cft,
if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
- mutex_lock(&cgroup_root_mutex);
- strcpy(cgrp->root->release_agent_path, buffer);
- mutex_unlock(&cgroup_root_mutex);
+ root_cgrp = cgroup_get_local_root(cgrp);
+ BUG_ON(!root_cgrp);
+ if (root_cgrp->ve_owner)
+ ret = ve_set_release_agent_path(root_cgrp, buffer);
+ else
+ return -ENODEV;
+
mutex_unlock(&cgroup_mutex);
- return 0;
+ return ret;
}
static int cgroup_release_agent_show(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *seq)
{
+ const char *release_agent;
+ struct cgroup *root_cgrp;
+
if (!cgroup_lock_live_group(cgrp))
return -ENODEV;
- seq_puts(seq, cgrp->root->release_agent_path);
+
+ root_cgrp = cgroup_get_local_root(cgrp);
+ if (root_cgrp->ve_owner) {
+ rcu_read_lock();
+ release_agent = ve_get_release_agent_path(root_cgrp);
+
+ if (release_agent)
+ seq_puts(seq, release_agent);
+ rcu_read_unlock();
+ }
seq_putc(seq, '\n');
mutex_unlock(&cgroup_mutex);
return 0;
@@ -5532,15 +5583,24 @@ static void check_for_release(struct cgroup *cgrp)
void cgroup_release_agent(struct work_struct *work)
{
struct ve_struct *ve;
+ char *agentbuf;
+
+ agentbuf = kzalloc(PATH_MAX, GFP_KERNEL);
+ if (!agentbuf) {
+ pr_warn("failed to allocate agentbuf\n");
+ return;
+ }
+
ve = container_of(work, struct ve_struct, release_agent_work);
mutex_lock(&cgroup_mutex);
raw_spin_lock(&ve->release_list_lock);
while (!list_empty(&ve->release_list)) {
char *argv[3], *envp[3];
int i, err;
- char *pathbuf = NULL, *agentbuf = NULL;
+ char *pathbuf = NULL;
struct cgroup *cgrp, *root_cgrp;
struct task_struct *ve_task;
+ const char *release_agent;
cgrp = list_entry(ve->release_list.next,
struct cgroup,
@@ -5568,9 +5628,15 @@ void cgroup_release_agent(struct work_struct *work)
rcu_read_unlock();
goto continue_free;
}
+
+ release_agent = ve_get_release_agent_path(root_cgrp);
+
+ *agentbuf = 0;
+ if (release_agent)
+ strncpy(agentbuf, release_agent, PATH_MAX);
rcu_read_unlock();
- agentbuf = kstrdup(cgrp->root->release_agent_path, GFP_KERNEL);
- if (!agentbuf)
+
+ if (!*agentbuf)
goto continue_free;
i = 0;
@@ -5601,11 +5667,11 @@ void cgroup_release_agent(struct work_struct *work)
mutex_lock(&cgroup_mutex);
continue_free:
kfree(pathbuf);
- kfree(agentbuf);
raw_spin_lock(&ve->release_list_lock);
}
raw_spin_unlock(&ve->release_list_lock);
mutex_unlock(&cgroup_mutex);
+ kfree(agentbuf);
}
static int __init cgroup_disable(char *str)
diff --git a/kernel/ve/ve.c b/kernel/ve/ve.c
index f564dca..f03f665 100644
--- a/kernel/ve/ve.c
+++ b/kernel/ve/ve.c
@@ -51,6 +51,11 @@ struct per_cgroot_data {
* data is related to this cgroup
*/
struct cgroup *cgroot;
+ /*
+ * path to release agent binaray, that should
+ * be spawned for all cgroups under this cgroup root
+ */
+ struct cgroup_rcu_string __rcu *release_agent_path;
};
extern struct kmapset_set sysfs_ve_perms_set;
@@ -175,6 +180,68 @@ static inline struct per_cgroot_data *per_cgroot_get_or_create(
return data;
}
+int ve_set_release_agent_path(struct cgroup *cgroot,
+ const char *release_agent)
+{
+ struct ve_struct *ve;
+ struct per_cgroot_data *data;
+ struct cgroup_rcu_string *new_path, *old_path;
+ int err = 0;
+
+ /*
+ * caller should grab cgroup_mutex to safely use
+ * ve_owner field
+ */
+ ve = cgroot->ve_owner;
+ BUG_ON(!ve);
+
+ new_path = cgroup_rcu_strdup(release_agent, strlen(release_agent));
+ if (IS_ERR(new_path))
+ return PTR_ERR(new_path);
+
+ data = per_cgroot_get_or_create(ve, cgroot);
+ if (IS_ERR(data)) {
+ kfree(new_path);
+ return PTR_ERR(data);
+ }
+
+ raw_spin_lock(&ve->per_cgroot_list_lock);
+
+ old_path = rcu_dereference_protected(data->release_agent_path,
+ lockdep_is_held(&ve->per_cgroot_list_lock));
+
+ rcu_assign_pointer(data->release_agent_path, new_path);
+ raw_spin_unlock(&ve->per_cgroot_list_lock);
+
+ if (old_path)
+ kfree_rcu(old_path, rcu_head);
+
+ return err;
+}
+
+const char *ve_get_release_agent_path(struct cgroup *cgroot)
+{
+ /* caller must grab rcu_read_lock */
+ const char *result = NULL;
+ struct per_cgroot_data *data;
+ struct cgroup_rcu_string *str;
+ struct ve_struct *ve;
+ ve = rcu_dereference(cgroot->ve_owner);
+ if (!ve)
+ return NULL;
+
+ raw_spin_lock(&ve->per_cgroot_list_lock);
+
+ data = per_cgroot_data_find_locked(&ve->per_cgroot_list, cgroot);
+ if (data) {
+ str = rcu_dereference(data->release_agent_path);
+ if (str)
+ result = str->val;
+ }
+ raw_spin_unlock(&ve->per_cgroot_list_lock);
+ return result;
+}
+
struct cgroup_subsys_state *ve_get_init_css(struct ve_struct *ve, int subsys_id)
{
struct cgroup_subsys_state *css, *tmp;
@@ -677,9 +744,14 @@ err_list:
static void ve_per_cgroot_free(struct ve_struct *ve)
{
struct per_cgroot_data *data, *saved;
+ struct cgroup_rcu_string *release_agent;
raw_spin_lock(&ve->per_cgroot_list_lock);
list_for_each_entry_safe(data, saved, &ve->per_cgroot_list, list) {
+ release_agent = data->release_agent_path;
+ RCU_INIT_POINTER(data->release_agent_path, NULL);
+ if (release_agent)
+ kfree_rcu(release_agent, rcu_head);
list_del_init(&data->list);
kfree(data);
}
--
1.8.3.1
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