client.c

linux 内核源代码

/* client.c: NFS client sharing and management code
 *
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells ([e-mail])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */


#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/metrics.h>
#include <linux/sunrpc/xprtsock.h>
#include <linux/sunrpc/xprtrdma.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/lockd/bind.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/nfs_idmap.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include <linux/nfs_xdr.h>

#include <asm/system.h>

#include "nfs4_fs.h"
#include "callback.h"
#include "delegation.h"
#include "iostat.h"
#include "internal.h"

#define NFSDBG_FACILITY		NFSDBG_CLIENT

static DEFINE_SPINLOCK(nfs_client_lock);
static LIST_HEAD(nfs_client_list);
static LIST_HEAD(nfs_volume_list);
static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);

/*
 * RPC cruft for NFS
 */
static struct rpc_version *nfs_version[5] = {
	[2]			= &nfs_version2,
#ifdef CONFIG_NFS_V3
	[3]			= &nfs_version3,
#endif
#ifdef CONFIG_NFS_V4
	[4]			= &nfs_version4,
#endif
};

struct rpc_program nfs_program = {
	.name			= "nfs",
	.number			= NFS_PROGRAM,
	.nrvers			= ARRAY_SIZE(nfs_version),
	.version		= nfs_version,
	.stats			= &nfs_rpcstat,
	.pipe_dir_name		= "/nfs",
};

struct rpc_stat nfs_rpcstat = {
	.program		= &nfs_program
};


#ifdef CONFIG_NFS_V3_ACL
static struct rpc_stat		nfsacl_rpcstat = { &nfsacl_program };
static struct rpc_version *	nfsacl_version[] = {
	[3]			= &nfsacl_version3,
};

struct rpc_program		nfsacl_program = {
	.name			= "nfsacl",
	.number			= NFS_ACL_PROGRAM,
	.nrvers			= ARRAY_SIZE(nfsacl_version),
	.version		= nfsacl_version,
	.stats			= &nfsacl_rpcstat,
};
#endif  /* CONFIG_NFS_V3_ACL */

/*
 * Allocate a shared client record
 *
 * Since these are allocated/deallocated very rarely, we don't
 * bother putting them in a slab cache...
 */
static struct nfs_client *nfs_alloc_client(const char *hostname,
					   const struct sockaddr_in *addr,
					   int nfsversion)
{
	struct nfs_client *clp;

	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
		goto error_0;

	if (nfsversion == 4) {
		if (nfs_callback_up() < 0)
			goto error_2;
		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
	}

	atomic_set(&clp->cl_count, 1);
	clp->cl_cons_state = NFS_CS_INITING;

	clp->cl_nfsversion = nfsversion;
	memcpy(&clp->cl_addr, addr, sizeof(clp->cl_addr));

	if (hostname) {
		clp->cl_hostname = kstrdup(hostname, GFP_KERNEL);
		if (!clp->cl_hostname)
			goto error_3;
	}

	INIT_LIST_HEAD(&clp->cl_superblocks);
	clp->cl_rpcclient = ERR_PTR(-EINVAL);

#ifdef CONFIG_NFS_V4
	init_rwsem(&clp->cl_sem);
	INIT_LIST_HEAD(&clp->cl_delegations);
	spin_lock_init(&clp->cl_lock);
	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS client");
	clp->cl_boot_time = CURRENT_TIME;
	clp->cl_state = 1 << NFS4CLNT_LEASE_EXPIRED;
#endif

	return clp;

error_3:
	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
		nfs_callback_down();
error_2:
	kfree(clp);
error_0:
	return NULL;
}

static void nfs4_shutdown_client(struct nfs_client *clp)
{
#ifdef CONFIG_NFS_V4
	if (__test_and_clear_bit(NFS_CS_RENEWD, &clp->cl_res_state))
		nfs4_kill_renewd(clp);
	BUG_ON(!RB_EMPTY_ROOT(&clp->cl_state_owners));
	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
		nfs_idmap_delete(clp);
#endif
}

/*
 * Destroy a shared client record
 */
static void nfs_free_client(struct nfs_client *clp)
{
	dprintk("--> nfs_free_client(%d)\n", clp->cl_nfsversion);

	nfs4_shutdown_client(clp);

	/* -EIO all pending I/O */
	if (!IS_ERR(clp->cl_rpcclient))
		rpc_shutdown_client(clp->cl_rpcclient);

	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
		nfs_callback_down();

	kfree(clp->cl_hostname);
	kfree(clp);

	dprintk("<-- nfs_free_client()\n");
}

/*
 * Release a reference to a shared client record
 */
void nfs_put_client(struct nfs_client *clp)
{
	if (!clp)
		return;

	dprintk("--> nfs_put_client({%d})\n", atomic_read(&clp->cl_count));

	if (atomic_dec_and_lock(&clp->cl_count, &nfs_client_lock)) {
		list_del(&clp->cl_share_link);
		spin_unlock(&nfs_client_lock);

		BUG_ON(!list_empty(&clp->cl_superblocks));

		nfs_free_client(clp);
	}
}

/*
 * Find a client by address
 * - caller must hold nfs_client_lock
 */
static struct nfs_client *__nfs_find_client(const struct sockaddr_in *addr, int nfsversion, int match_port)
{
	struct nfs_client *clp;

	list_for_each_entry(clp, &nfs_client_list, cl_share_link) {
		/* Don't match clients that failed to initialise properly */
		if (clp->cl_cons_state < 0)
			continue;

		/* Different NFS versions cannot share the same nfs_client */
		if (clp->cl_nfsversion != nfsversion)
			continue;

		if (memcmp(&clp->cl_addr.sin_addr, &addr->sin_addr,
			   sizeof(clp->cl_addr.sin_addr)) != 0)
			continue;

		if (!match_port || clp->cl_addr.sin_port == addr->sin_port)
			goto found;
	}

	return NULL;

found:
	atomic_inc(&clp->cl_count);
	return clp;
}

/*
 * Find a client by IP address and protocol version
 * - returns NULL if no such client
 */
struct nfs_client *nfs_find_client(const struct sockaddr_in *addr, int nfsversion)
{
	struct nfs_client *clp;

	spin_lock(&nfs_client_lock);
	clp = __nfs_find_client(addr, nfsversion, 0);
	spin_unlock(&nfs_client_lock);
	if (clp != NULL && clp->cl_cons_state != NFS_CS_READY) {
		nfs_put_client(clp);
		clp = NULL;
	}
	return clp;
}

/*
 * Look up a client by IP address and protocol version
 * - creates a new record if one doesn't yet exist
 */
static struct nfs_client *nfs_get_client(const char *hostname,
					 const struct sockaddr_in *addr,
					 int nfsversion)
{
	struct nfs_client *clp, *new = NULL;
	int error;

	dprintk("--> nfs_get_client(%s,"NIPQUAD_FMT":%d,%d)\n",
		hostname ?: "", NIPQUAD(addr->sin_addr),
		addr->sin_port, nfsversion);

	/* see if the client already exists */
	do {
		spin_lock(&nfs_client_lock);

		clp = __nfs_find_client(addr, nfsversion, 1);
		if (clp)
			goto found_client;
		if (new)
			goto install_client;

		spin_unlock(&nfs_client_lock);

		new = nfs_alloc_client(hostname, addr, nfsversion);
	} while (new);

	return ERR_PTR(-ENOMEM);

	/* install a new client and return with it unready */
install_client:
	clp = new;
	list_add(&clp->cl_share_link, &nfs_client_list);
	spin_unlock(&nfs_client_lock);
	dprintk("--> nfs_get_client() = %p [new]\n", clp);
	return clp;

	/* found an existing client
	 * - make sure it's ready before returning
	 */
found_client:
	spin_unlock(&nfs_client_lock);

	if (new)
		nfs_free_client(new);

	error = wait_event_interruptible(nfs_client_active_wq,
				clp->cl_cons_state != NFS_CS_INITING);
	if (error < 0) {
		nfs_put_client(clp);
		return ERR_PTR(-ERESTARTSYS);
	}

	if (clp->cl_cons_state < NFS_CS_READY) {
		error = clp->cl_cons_state;
		nfs_put_client(clp);
		return ERR_PTR(error);
	}

	BUG_ON(clp->cl_cons_state != NFS_CS_READY);

	dprintk("--> nfs_get_client() = %p [share]\n", clp);
	return clp;
}

/*
 * Mark a server as ready or failed
 */
static void nfs_mark_client_ready(struct nfs_client *clp, int state)
{
	clp->cl_cons_state = state;
	wake_up_all(&nfs_client_active_wq);
}

/*
 * Initialise the timeout values for a connection
 */
static void nfs_init_timeout_values(struct rpc_timeout *to, int proto,
				    unsigned int timeo, unsigned int retrans)
{
	to->to_initval = timeo * HZ / 10;
	to->to_retries = retrans;
	if (!to->to_retries)
		to->to_retries = 2;

	switch (proto) {
	case XPRT_TRANSPORT_TCP:
	case XPRT_TRANSPORT_RDMA:
		if (!to->to_initval)
			to->to_initval = 60 * HZ;
		if (to->to_initval > NFS_MAX_TCP_TIMEOUT)
			to->to_initval = NFS_MAX_TCP_TIMEOUT;
		to->to_increment = to->to_initval;
		to->to_maxval = to->to_initval + (to->to_increment * to->to_retries);
		to->to_exponential = 0;
		break;
	case XPRT_TRANSPORT_UDP:
	default:
		if (!to->to_initval)
			to->to_initval = 11 * HZ / 10;
		if (to->to_initval > NFS_MAX_UDP_TIMEOUT)
			to->to_initval = NFS_MAX_UDP_TIMEOUT;
		to->to_maxval = NFS_MAX_UDP_TIMEOUT;
		to->to_exponential = 1;
		break;
	}
}

/*
 * Create an RPC client handle
 */
static int nfs_create_rpc_client(struct nfs_client *clp, int proto,
						unsigned int timeo,
						unsigned int retrans,
						rpc_authflavor_t flavor,
						int flags)
{
	struct rpc_timeout	timeparms;
	struct rpc_clnt		*clnt = NULL;
	struct rpc_create_args args = {
		.protocol	= proto,
		.address	= (struct sockaddr *)&clp->cl_addr,
		.addrsize	= sizeof(clp->cl_addr),
		.timeout	= &timeparms,
		.servername	= clp->cl_hostname,
		.program	= &nfs_program,
		.version	= clp->rpc_ops->version,
		.authflavor	= flavor,
		.flags		= flags,
	};

	if (!IS_ERR(clp->cl_rpcclient))
		return 0;

	nfs_init_timeout_values(&timeparms, proto, timeo, retrans);
	clp->retrans_timeo = timeparms.to_initval;
	clp->retrans_count = timeparms.to_retries;

	clnt = rpc_create(&args);
	if (IS_ERR(clnt)) {
		dprintk("%s: cannot create RPC client. Error = %ld\n",
				__FUNCTION__, PTR_ERR(clnt));
		return PTR_ERR(clnt);
	}

	clp->cl_rpcclient = clnt;
	return 0;
}

/*
 * Version 2 or 3 client destruction
 */
static void nfs_destroy_server(struct nfs_server *server)
{
	if (!(server->flags & NFS_MOUNT_NONLM))
		lockd_down();	/* release rpc.lockd */
}

/*
 * Version 2 or 3 lockd setup
 */
static int nfs_start_lockd(struct nfs_server *server)
{
	int error = 0;

	if (server->nfs_client->cl_nfsversion > 3)
		goto out;
	if (server->flags & NFS_MOUNT_NONLM)
		goto out;
	error = lockd_up((server->flags & NFS_MOUNT_TCP) ?
			IPPROTO_TCP : IPPROTO_UDP);
	if (error < 0)
		server->flags |= NFS_MOUNT_NONLM;
	else
		server->destroy = nfs_destroy_server;
out:
	return error;
}

/*
 * Initialise an NFSv3 ACL client connection
 */
#ifdef CONFIG_NFS_V3_ACL
static void nfs_init_server_aclclient(struct nfs_server *server)
{
	if (server->nfs_client->cl_nfsversion != 3)
		goto out_noacl;
	if (server->flags & NFS_MOUNT_NOACL)
		goto out_noacl;

	server->client_acl = rpc_bind_new_program(server->client, &nfsacl_program, 3);
	if (IS_ERR(server->client_acl))
		goto out_noacl;

	/* No errors! Assume that Sun nfsacls are supported */
	server->caps |= NFS_CAP_ACLS;
	return;

out_noacl:
	server->caps &= ~NFS_CAP_ACLS;
}
#else
static inline void nfs_init_server_aclclient(struct nfs_server *server)
{
	server->flags &= ~NFS_MOUNT_NOACL;
	server->caps &= ~NFS_CAP_ACLS;
}
#endif

/*