path: root/fs/nfs/client.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* client.c: NFS client sharing and management code
 *
 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */


#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/addr.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/vfs.h>
#include <linux/inet.h>
#include <linux/in6.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <net/ipv6.h>
#include <linux/nfs_xdr.h>
#include <linux/sunrpc/bc_xprt.h>
#include <linux/nsproxy.h>
#include <linux/pid_namespace.h>
#include <linux/nfslocalio.h>

#include "nfs4_fs.h"
#include "callback.h"
#include "delegation.h"
#include "iostat.h"
#include "internal.h"
#include "fscache.h"
#include "pnfs.h"
#include "nfs.h"
#include "netns.h"
#include "sysfs.h"
#include "nfs42.h"

#define NFSDBG_FACILITY		NFSDBG_CLIENT

static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
static DEFINE_RWLOCK(nfs_version_lock);

static struct nfs_subversion *nfs_version_mods[5] = {
	[2] = NULL,
	[3] = NULL,
	[4] = NULL,
};

/*
 * RPC cruft for NFS
 */
static const struct rpc_version *nfs_version[5] = {
	[2] = NULL,
	[3] = NULL,
	[4] = NULL,
};

const struct rpc_program nfs_program = {
	.name			= "nfs",
	.number			= NFS_PROGRAM,
	.nrvers			= ARRAY_SIZE(nfs_version),
	.version		= nfs_version,
	.pipe_dir_name		= NFS_PIPE_DIRNAME,
};

static struct nfs_subversion *__find_nfs_version(unsigned int version)
{
	struct nfs_subversion *nfs;

	read_lock(&nfs_version_lock);
	nfs = nfs_version_mods[version];
	read_unlock(&nfs_version_lock);
	return nfs;
}

struct nfs_subversion *find_nfs_version(unsigned int version)
{
	struct nfs_subversion *nfs = __find_nfs_version(version);

	if (!nfs && request_module("nfsv%d", version) == 0)
		nfs = __find_nfs_version(version);

	if (!nfs)
		return ERR_PTR(-EPROTONOSUPPORT);

	if (!get_nfs_version(nfs))
		return ERR_PTR(-EAGAIN);

	return nfs;
}

int get_nfs_version(struct nfs_subversion *nfs)
{
	return try_module_get(nfs->owner);
}
EXPORT_SYMBOL_GPL(get_nfs_version);

void put_nfs_version(struct nfs_subversion *nfs)
{
	module_put(nfs->owner);
}

void register_nfs_version(struct nfs_subversion *nfs)
{
	write_lock(&nfs_version_lock);

	nfs_version_mods[nfs->rpc_ops->version] = nfs;
	nfs_version[nfs->rpc_ops->version] = nfs->rpc_vers;

	write_unlock(&nfs_version_lock);
}
EXPORT_SYMBOL_GPL(register_nfs_version);

void unregister_nfs_version(struct nfs_subversion *nfs)
{
	write_lock(&nfs_version_lock);

	nfs_version[nfs->rpc_ops->version] = NULL;
	nfs_version_mods[nfs->rpc_ops->version] = NULL;

	write_unlock(&nfs_version_lock);
}
EXPORT_SYMBOL_GPL(unregister_nfs_version);

/*
 * Allocate a shared client record
 *
 * Since these are allocated/deallocated very rarely, we don't
 * bother putting them in a slab cache...
 */
struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
{
	struct nfs_client *clp;
	int err = -ENOMEM;

	if ((clp = kzalloc_obj(*clp)) == NULL)
		goto error_0;

	clp->cl_minorversion = cl_init->minorversion;
	clp->cl_nfs_mod = cl_init->nfs_mod;
	if (!get_nfs_version(clp->cl_nfs_mod))
		goto error_dealloc;

	clp->rpc_ops = clp->cl_nfs_mod->rpc_ops;

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

	memcpy(&clp->cl_addr, cl_init->addr, cl_init->addrlen);
	clp->cl_addrlen = cl_init->addrlen;

	if (cl_init->hostname) {
		err = -ENOMEM;
		clp->cl_hostname = kstrdup(cl_init->hostname, GFP_KERNEL);
		if (!clp->cl_hostname)
			goto error_cleanup;
	}

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

	clp->cl_flags = cl_init->init_flags;
	clp->cl_proto = cl_init->proto;
	clp->cl_nconnect = cl_init->nconnect;
	clp->cl_max_connect = cl_init->max_connect ? cl_init->max_connect : 1;
	clp->cl_net = get_net_track(cl_init->net, &clp->cl_ns_tracker, GFP_KERNEL);

#if IS_ENABLED(CONFIG_NFS_LOCALIO)
	seqlock_init(&clp->cl_boot_lock);
	ktime_get_real_ts64(&clp->cl_nfssvc_boot);
	nfs_uuid_init(&clp->cl_uuid);
	INIT_WORK(&clp->cl_local_probe_work, nfs_local_probe_async_work);
#endif /* CONFIG_NFS_LOCALIO */

	clp->cl_principal = "*";
	clp->cl_xprtsec = cl_init->xprtsec;
	return clp;

error_cleanup:
	put_nfs_version(clp->cl_nfs_mod);
error_dealloc:
	kfree(clp);
error_0:
	return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(nfs_alloc_client);

#if IS_ENABLED(CONFIG_NFS_V4)
static void nfs_cleanup_cb_ident_idr(struct net *net)
{
	struct nfs_net *nn = net_generic(net, nfs_net_id);

	idr_destroy(&nn->cb_ident_idr);
}

/* nfs_client_lock held */
static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
{
	struct nfs_net *nn = net_generic(clp->cl_net, nfs_net_id);

	if (clp->cl_cb_ident)
		idr_remove(&nn->cb_ident_idr, clp->cl_cb_ident);
}

static void pnfs_init_server(struct nfs_server *server)
{
	rpc_init_wait_queue(&server->roc_rpcwaitq, "pNFS ROC");
}

#else
static void nfs_cleanup_cb_ident_idr(struct net *net)
{
}

static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
{
}

static void pnfs_init_server(struct nfs_server *server)
{
}

#endif /* CONFIG_NFS_V4 */

/*
 * Destroy a shared client record
 */
void nfs_free_client(struct nfs_client *clp)
{
	nfs_localio_disable_client(clp);

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

	put_net_track(clp->cl_net, &clp->cl_ns_tracker);
	put_nfs_version(clp->cl_nfs_mod);
	kfree(clp->cl_hostname);
	kfree(clp->cl_acceptor);
	kfree_rcu(clp, rcu);
}
EXPORT_SYMBOL_GPL(nfs_free_client);

/*
 * Release a reference to a shared client record
 */
void nfs_put_client(struct nfs_client *clp)
{
	struct nfs_net *nn;

	if (!clp)
		return;

	nn = net_generic(clp->cl_net, nfs_net_id);

	if (refcount_dec_and_lock(&clp->cl_count, &nn->nfs_client_lock)) {
		list_del(&clp->cl_share_link);
		nfs_cb_idr_remove_locked(clp);
		spin_unlock(&nn->nfs_client_lock);

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

		clp->rpc_ops->free_client(clp);
	}
}
EXPORT_SYMBOL_GPL(nfs_put_client);

/*
 * Find an nfs_client on the list that matches the initialisation data
 * that is supplied.
 */
static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *data)
{
	struct nfs_client *clp;
	const struct sockaddr *sap = (struct sockaddr *)data->addr;
	struct nfs_net *nn = net_generic(data->net, nfs_net_id);
	int error;

again:
	list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
	        const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
		/* Don't match clients that failed to initialise properly */
		if (clp->cl_cons_state < 0)
			continue;

		/* If a client is still initializing then we need to wait */
		if (clp->cl_cons_state > NFS_CS_READY) {
			refcount_inc(&clp->cl_count);
			spin_unlock(&nn->nfs_client_lock);
			error = nfs_wait_client_init_complete(clp);
			nfs_put_client(clp);
			spin_lock(