Commit bf11fbdb authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Add sysfs support for per-container identifier 



In order to identify containers to the NFS client, we add a per-net
sysfs attribute that udev can fill with the appropriate identifier.
The identifier could be a unique hostname, but in most cases it
will probably be a persisted uuid.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 10b7a70c

fs/nfs/client.c

+4 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ 
#include "pnfs.h"

#include "nfs.h"

#include "netns.h"

#include "sysfs.h"



#define NFSDBG_FACILITY		NFSDBG_CLIENT
@@ -1072,12 +1073,15 @@ void nfs_clients_init(struct net *net) 
#endif

	spin_lock_init(&nn->nfs_client_lock);

	nn->boot_time = ktime_get_real();



	nfs_netns_sysfs_setup(nn, net);

}



void nfs_clients_exit(struct net *net)

{

	struct nfs_net *nn = net_generic(net, nfs_net_id);



	nfs_netns_sysfs_destroy(nn);

	nfs_cleanup_cb_ident_idr(net);

	WARN_ON_ONCE(!list_empty(&nn->nfs_client_list));

	WARN_ON_ONCE(!list_empty(&nn->nfs_volume_list));

fs/nfs/netns.h

+3 −0
Original line number Diff line number Diff line
@@ -15,6 +15,8 @@ struct bl_dev_msg { 
	uint32_t major, minor;

};



struct nfs_netns_client;



struct nfs_net {

	struct cache_detail *nfs_dns_resolve;

	struct rpc_pipe *bl_device_pipe;
@@ -29,6 +31,7 @@ struct nfs_net { 
	unsigned short nfs_callback_tcpport6;

	int cb_users[NFS4_MAX_MINOR_VERSION + 1];

#endif

	struct nfs_netns_client *nfs_client;

	spinlock_t nfs_client_lock;

	ktime_t boot_time;

#ifdef CONFIG_PROC_FS

fs/nfs/sysfs.c

+118 −0
Original line number Diff line number Diff line
@@ -9,7 +9,12 @@ 
#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;
@@ -67,3 +72,116 @@ 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);

	return scnprintf(buf, PAGE_SIZE, "%s\n", c->identifier);

}



/* 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 = xchg(&c->identifier, p);

	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);



	if (c->identifier)

		kfree(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,

};



static struct kobj_type nfs_netns_client_type = {

	.release = nfs_netns_client_release,

	.default_attrs = nfs_netns_client_attrs,

	.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;

	}

}

fs/nfs/sysfs.h

+10 −0
Original line number Diff line number Diff line
@@ -6,10 +6,20 @@ 
#ifndef __NFS_SYSFS_H

#define __NFS_SYSFS_H



#define CONTAINER_ID_MAXLEN (64)



struct nfs_netns_client {

	struct kobject kobject;

	struct net *net;

	const char *identifier;

};



extern struct kobject *nfs_client_kobj;



extern int nfs_sysfs_init(void);

extern void nfs_sysfs_exit(void);



void nfs_netns_sysfs_setup(struct nfs_net *netns, struct net *net);

void nfs_netns_sysfs_destroy(struct nfs_net *netns);



#endif