linux/fs/nfs/sysfs.c
Trond Myklebust b38e09b9b6 Revert "NFSv4: use unique client identifiers in network namespaces"
This reverts commit 50c790a0b6.

The functionality is believed to be capable of causing regressions in
existing setups, so the author has requested that it be reverted.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
2022-02-28 10:09:23 -05:00

193 lines
4.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2019 Hammerspace Inc
*/
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/sysfs.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/netdevice.h>
#include <linux/string.h>
#include <linux/nfs_fs.h>
#include <linux/rcupdate.h>
#include "nfs4_fs.h"
#include "netns.h"
#include "sysfs.h"
struct kobject *nfs_client_kobj;
static struct kset *nfs_client_kset;
static void nfs_netns_object_release(struct kobject *kobj)
{
kfree(kobj);
}
static const struct kobj_ns_type_operations *nfs_netns_object_child_ns_type(
struct kobject *kobj)
{
return &net_ns_type_operations;
}
static struct kobj_type nfs_netns_object_type = {
.release = nfs_netns_object_release,
.sysfs_ops = &kobj_sysfs_ops,
.child_ns_type = nfs_netns_object_child_ns_type,
};
static struct kobject *nfs_netns_object_alloc(const char *name,
struct kset *kset, struct kobject *parent)
{
struct kobject *kobj;
kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
if (kobj) {
kobj->kset = kset;
if (kobject_init_and_add(kobj, &nfs_netns_object_type,
parent, "%s", name) == 0)
return kobj;
kobject_put(kobj);
}
return NULL;
}
int nfs_sysfs_init(void)
{
nfs_client_kset = kset_create_and_add("nfs", NULL, fs_kobj);
if (!nfs_client_kset)
return -ENOMEM;
nfs_client_kobj = nfs_netns_object_alloc("net", nfs_client_kset, NULL);
if (!nfs_client_kobj) {
kset_unregister(nfs_client_kset);
nfs_client_kset = NULL;
return -ENOMEM;
}
return 0;
}
void nfs_sysfs_exit(void)
{
kobject_put(nfs_client_kobj);
kset_unregister(nfs_client_kset);
}
static ssize_t nfs_netns_identifier_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct nfs_netns_client *c = container_of(kobj,
struct nfs_netns_client,
kobject);
ssize_t ret;
rcu_read_lock();
ret = scnprintf(buf, PAGE_SIZE, "%s\n", rcu_dereference(c->identifier));
rcu_read_unlock();
return ret;
}
/* Strip trailing '\n' */
static size_t nfs_string_strip(const char *c, size_t len)
{
while (len > 0 && c[len-1] == '\n')
--len;
return len;
}
static ssize_t nfs_netns_identifier_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
struct nfs_netns_client *c = container_of(kobj,
struct nfs_netns_client,
kobject);
const char *old;
char *p;
size_t len;
len = nfs_string_strip(buf, min_t(size_t, count, CONTAINER_ID_MAXLEN));
if (!len)
return 0;
p = kmemdup_nul(buf, len, GFP_KERNEL);
if (!p)
return -ENOMEM;
old = rcu_dereference_protected(xchg(&c->identifier, (char __rcu *)p), 1);
if (old) {
synchronize_rcu();
kfree(old);
}
return count;
}
static void nfs_netns_client_release(struct kobject *kobj)
{
struct nfs_netns_client *c = container_of(kobj,
struct nfs_netns_client,
kobject);
kfree(rcu_dereference_raw(c->identifier));
kfree(c);
}
static const void *nfs_netns_client_namespace(struct kobject *kobj)
{
return container_of(kobj, struct nfs_netns_client, kobject)->net;
}
static struct kobj_attribute nfs_netns_client_id = __ATTR(identifier,
0644, nfs_netns_identifier_show, nfs_netns_identifier_store);
static struct attribute *nfs_netns_client_attrs[] = {
&nfs_netns_client_id.attr,
NULL,
};
ATTRIBUTE_GROUPS(nfs_netns_client);
static struct kobj_type nfs_netns_client_type = {
.release = nfs_netns_client_release,
.default_groups = nfs_netns_client_groups,
.sysfs_ops = &kobj_sysfs_ops,
.namespace = nfs_netns_client_namespace,
};
static struct nfs_netns_client *nfs_netns_client_alloc(struct kobject *parent,
struct net *net)
{
struct nfs_netns_client *p;
p = kzalloc(sizeof(*p), GFP_KERNEL);
if (p) {
p->net = net;
p->kobject.kset = nfs_client_kset;
if (kobject_init_and_add(&p->kobject, &nfs_netns_client_type,
parent, "nfs_client") == 0)
return p;
kobject_put(&p->kobject);
}
return NULL;
}
void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net)
{
struct nfs_netns_client *clp;
clp = nfs_netns_client_alloc(nfs_client_kobj, net);
if (clp) {
netns->nfs_client = clp;
kobject_uevent(&clp->kobject, KOBJ_ADD);
}
}
void nfs_netns_sysfs_destroy(struct nfs_net *netns)
{
struct nfs_netns_client *clp = netns->nfs_client;
if (clp) {
kobject_uevent(&clp->kobject, KOBJ_REMOVE);
kobject_del(&clp->kobject);
kobject_put(&clp->kobject);
netns->nfs_client = NULL;
}
}