[linux-2.6-block.git] / fs / nfs / nfs4super.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/nfs4_mount.h>
#include <linux/nfs_fs.h>
#include "delegation.h"
#include "internal.h"
#include "nfs4_fs.h"
#include "nfs4idmap.h"
#include "dns_resolve.h"
#include "pnfs.h"
#include "nfs.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc);
static void nfs4_evict_inode(struct inode *inode);
static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);
static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type,
	int flags, const char *dev_name, void *raw_data);

static struct file_system_type nfs4_remote_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_remote_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};

static struct file_system_type nfs4_remote_referral_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_remote_referral_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};

struct file_system_type nfs4_referral_fs_type = {
	.owner		= THIS_MODULE,
	.name		= "nfs4",
	.mount		= nfs4_referral_mount,
	.kill_sb	= nfs_kill_super,
	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA,
};

static const struct super_operations nfs4_sops = {
	.alloc_inode	= nfs_alloc_inode,
	.free_inode	= nfs_free_inode,
	.write_inode	= nfs4_write_inode,
	.drop_inode	= nfs_drop_inode,
	.statfs		= nfs_statfs,
	.evict_inode	= nfs4_evict_inode,
	.umount_begin	= nfs_umount_begin,
	.show_options	= nfs_show_options,
	.show_devname	= nfs_show_devname,
	.show_path	= nfs_show_path,
	.show_stats	= nfs_show_stats,
	.remount_fs	= nfs_remount,
};

struct nfs_subversion nfs_v4 = {
	.owner = THIS_MODULE,
	.nfs_fs   = &nfs4_fs_type,
	.rpc_vers = &nfs_version4,
	.rpc_ops  = &nfs_v4_clientops,
	.sops     = &nfs4_sops,
	.xattr    = nfs4_xattr_handlers,
};

static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
{
	int ret = nfs_write_inode(inode, wbc);

	if (ret == 0)
		ret = pnfs_layoutcommit_inode(inode,
				wbc->sync_mode == WB_SYNC_ALL);
	return ret;
}

/*
 * Clean out any remaining NFSv4 state that might be left over due
 * to open() calls that passed nfs_atomic_lookup, but failed to call
 * nfs_open().
 */
static void nfs4_evict_inode(struct inode *inode)
{
	truncate_inode_pages_final(&inode->i_data);
	clear_inode(inode);
	/* If we are holding a delegation, return it! */
	nfs_inode_return_delegation_noreclaim(inode);
	/* Note that above delegreturn would trigger pnfs return-on-close */
	pnfs_return_layout(inode);
	pnfs_destroy_layout(NFS_I(inode));
	/* First call standard NFS clear_inode() code */
	nfs_clear_inode(inode);
}

/*
 * Get the superblock for the NFS4 root partition
 */
static struct dentry *
nfs4_remote_mount(struct file_system_type *fs_type, int flags,
		  const char *dev_name, void *info)
{
	struct nfs_mount_info *mount_info = info;
	struct nfs_server *server;
	struct dentry *mntroot = ERR_PTR(-ENOMEM);

	mount_info->set_security = nfs_set_sb_security;

	/* Get a volume representation */
	server = nfs4_create_server(mount_info, &nfs_v4);
	if (IS_ERR(server)) {
		mntroot = ERR_CAST(server);
		goto out;
	}

	mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);

out:
	return mntroot;
}

static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type,
		int flags, void *data, const char *hostname)
{
	struct vfsmount *root_mnt;
	char *root_devname;
	size_t len;

	len = strlen(hostname) + 5;
	root_devname = kmalloc(len, GFP_KERNEL);
	if (root_devname == NULL)
		return ERR_PTR(-ENOMEM);
	/* Does hostname needs to be enclosed in brackets? */
	if (strchr(hostname, ':'))
		snprintf(root_devname, len, "[%s]:/", hostname);
	else
		snprintf(root_devname, len, "%s:/", hostname);
	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
	kfree(root_devname);
	return root_mnt;
}

struct nfs_referral_count {
	struct list_head list;
	const struct task_struct *task;
	unsigned int referral_count;
};

static LIST_HEAD(nfs_referral_count_list);
static DEFINE_SPINLOCK(nfs_referral_count_list_lock);

static struct nfs_referral_count *nfs_find_referral_count(void)
{
	struct nfs_referral_count *p;

	list_for_each_entry(p, &nfs_referral_count_list, list) {
		if (p->task == current)
			return p;
	}
	return NULL;
}

#define NFS_MAX_NESTED_REFERRALS 2

static int nfs_referral_loop_protect(void)
{
	struct nfs_referral_count *p, *new;
	int ret = -ENOMEM;

	new = kmalloc(sizeof(*new), GFP_KERNEL);
	if (!new)
		goto out;
	new->task = current;
	new->referral_count = 1;

	ret = 0;
	spin_lock(&nfs_referral_count_list_lock);
	p = nfs_find_referral_count();
	if (p != NULL) {
		if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
			ret = -ELOOP;
		else
			p->referral_count++;
	} else {
		list_add(&new->list, &nfs_referral_count_list);
		new = NULL;
	}
	spin_unlock(&nfs_referral_count_list_lock);
	kfree(new);
out:
	return ret;
}

static void nfs_referral_loop_unprotect(void)
{
	struct nfs_referral_count *p;

	spin_lock(&nfs_referral_count_list_lock);
	p = nfs_find_referral_count();
	p->referral_count--;
	if (p->referral_count == 0)
		list_del(&p->list);
	else
		p = NULL;
	spin_unlock(&nfs_referral_count_list_lock);
	kfree(p);
}

static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt,
		const char *export_path)
{
	struct dentry *dentry;
	int err;

	if (IS_ERR(root_mnt))
		return ERR_CAST(root_mnt);

	err = nfs_referral_loop_protect();
	if (err) {
		mntput(root_mnt);
		return ERR_PTR(err);
	}

	dentry = mount_subtree(root_mnt, export_path);
	nfs_referral_loop_unprotect();

	return dentry;
}

struct dentry *nfs4_try_mount(int flags, const char *dev_name,
			      struct nfs_mount_info *mount_info,
			      struct nfs_subversion *nfs_mod)
{
	char *export_path;
	struct vfsmount *root_mnt;
	struct dentry *res;
	struct nfs_parsed_mount_data *data = mount_info->parsed;

	dfprintk(MOUNT, "--> nfs4_try_mount()\n");

	export_path = data->nfs_server.export_path;
	data->nfs_server.export_path = "/";
	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
			data->nfs_server.hostname);
	data->nfs_server.export_path = export_path;

	res = nfs_follow_remote_path(root_mnt, export_path);

	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n",
		 PTR_ERR_OR_ZERO(res),
		 IS_ERR(res) ? " [error]" : "");
	return res;
}

static struct dentry *
nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
			   const char *dev_name, void *raw_data)
{
	struct nfs_mount_info mount_info = {
		.fill_super = nfs_fill_super,
		.set_security = nfs_clone_sb_security,
		.cloned = raw_data,
	};
	struct nfs_server *server;
	struct dentry *mntroot = ERR_PTR(-ENOMEM);

	dprintk("--> nfs4_referral_get_sb()\n");

	mount_info.mntfh = nfs_alloc_fhandle();
	if (mount_info.cloned == NULL || mount_info.mntfh == NULL)
		goto out;

	/* create a new volume representation */
	server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
	if (IS_ERR(server)) {
		mntroot = ERR_CAST(server);
		goto out;
	}

	mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
out:
	nfs_free_fhandle(mount_info.mntfh);
	return mntroot;
}

/*
 * Create an NFS4 server record on referral traversal
 */
static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type,
		int flags, const char *dev_name, void *raw_data)
{
	struct nfs_clone_mount *data = raw_data;
	char *export_path;
	struct vfsmount *root_mnt;
	struct dentry *res;

	dprintk("--> nfs4_referral_mount()\n");

	export_path = data->mnt_path;
	data->mnt_path = "/";

	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
			flags, data, data->hostname);
	data->mnt_path = export_path;

	res = nfs_follow_remote_path(root_mnt, export_path);
	dprintk("<-- nfs4_referral_mount() = %d%s\n",
		PTR_ERR_OR_ZERO(res),
		IS_ERR(res) ? " [error]" : "");
	return res;
}


static int __init init_nfs_v4(void)
{
	int err;

	err = nfs_dns_resolver_init();
	if (err)
		goto out;

	err = nfs_idmap_init();
	if (err)
		goto out1;

	err = nfs4_register_sysctl();
	if (err)
		goto out2;

	register_nfs_version(&nfs_v4);
	return 0;
out2:
	nfs_idmap_quit();
out1:
	nfs_dns_resolver_destroy();
out:
	return err;
}

static void __exit exit_nfs_v4(void)
{
	/* Not called in the _init(), conditionally loaded */
	nfs4_pnfs_v3_ds_connect_unload();

	unregister_nfs_version(&nfs_v4);
	nfs4_unregister_sysctl();
	nfs_idmap_quit();
	nfs_dns_resolver_destroy();
}

MODULE_LICENSE("GPL");

module_init(init_nfs_v4);
module_exit(exit_nfs_v4);
Commit	Line	Data
09c434b8	1	// SPDX-License-Identifier: GPL-2.0-only
129d1977 BS	2	/*
	3	* Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com>
	4	*/
	5	#include <linux/init.h>
fbdefd64	6	#include <linux/module.h>
fbdefd64	7	#include <linux/nfs4_mount.h>
466bfe7f	8	#include <linux/nfs_fs.h>
19d87ca3	9	#include "delegation.h"
fbdefd64	10	#include "internal.h"
466bfe7f	11	#include "nfs4_fs.h"
40c64c26	12	#include "nfs4idmap.h"
c8d74d9b	13	#include "dns_resolve.h"
19d87ca3	14	#include "pnfs.h"
ab7017a3	15	#include "nfs.h"
129d1977	16
fbdefd64 BS	17	#define NFSDBG_FACILITY NFSDBG_VFS
fbdefd64 BS	18
19d87ca3 BS	19	static int nfs4_write_inode(struct inode inode, struct writeback_control wbc);
19d87ca3 BS	20	static void nfs4_evict_inode(struct inode *inode);
fbdefd64 BS	21	static struct dentry nfs4_remote_mount(struct file_system_type fs_type,
fbdefd64 BS	22	int flags, const char dev_name, void raw_data);
fbdefd64 BS	23	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
	24	int flags, const char dev_name, void raw_data);
	25	static struct dentry nfs4_remote_referral_mount(struct file_system_type fs_type,
	26	int flags, const char dev_name, void raw_data);
	27
fbdefd64 BS	28	static struct file_system_type nfs4_remote_fs_type = {
	29	.owner = THIS_MODULE,
	30	.name = "nfs4",
	31	.mount = nfs4_remote_mount,
	32	.kill_sb = nfs_kill_super,
ecf3d1f1	33	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_BINARY_MOUNTDATA,
fbdefd64 BS	34	};
fbdefd64 BS	35
fbdefd64 BS	36	static struct file_system_type nfs4_remote_referral_fs_type = {
	37	.owner = THIS_MODULE,
	38	.name = "nfs4",
	39	.mount = nfs4_remote_referral_mount,
	40	.kill_sb = nfs_kill_super,
ecf3d1f1	41	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_BINARY_MOUNTDATA,
fbdefd64 BS	42	};
	43
	44	struct file_system_type nfs4_referral_fs_type = {
	45	.owner = THIS_MODULE,
	46	.name = "nfs4",
	47	.mount = nfs4_referral_mount,
	48	.kill_sb = nfs_kill_super,
ecf3d1f1	49	.fs_flags = FS_RENAME_DOES_D_MOVE\|FS_BINARY_MOUNTDATA,
fbdefd64 BS	50	};
	51
	52	static const struct super_operations nfs4_sops = {
	53	.alloc_inode = nfs_alloc_inode,
ca1a199e	54	.free_inode = nfs_free_inode,
fbdefd64	55	.write_inode = nfs4_write_inode,
eed99357	56	.drop_inode = nfs_drop_inode,
fbdefd64 BS	57	.statfs = nfs_statfs,
	58	.evict_inode = nfs4_evict_inode,
	59	.umount_begin = nfs_umount_begin,
	60	.show_options = nfs_show_options,
	61	.show_devname = nfs_show_devname,
	62	.show_path = nfs_show_path,
	63	.show_stats = nfs_show_stats,
	64	.remount_fs = nfs_remount,
	65	};
	66
ab7017a3 BS	67	struct nfs_subversion nfs_v4 = {
	68	.owner = THIS_MODULE,
	69	.nfs_fs = &nfs4_fs_type,
	70	.rpc_vers = &nfs_version4,
	71	.rpc_ops = &nfs_v4_clientops,
6a74490d BS	72	.sops = &nfs4_sops,
6a74490d BS	73	.xattr = nfs4_xattr_handlers,
ab7017a3 BS	74	};
ab7017a3 BS	75
19d87ca3 BS	76	static int nfs4_write_inode(struct inode inode, struct writeback_control wbc)
	77	{
	78	int ret = nfs_write_inode(inode, wbc);
	79
71244d9b TM	80	if (ret == 0)
	81	ret = pnfs_layoutcommit_inode(inode,
	82	wbc->sync_mode == WB_SYNC_ALL);
19d87ca3 BS	83	return ret;
	84	}
	85
	86	/*
	87	* Clean out any remaining NFSv4 state that might be left over due
	88	* to open() calls that passed nfs_atomic_lookup, but failed to call
	89	* nfs_open().
	90	*/
	91	static void nfs4_evict_inode(struct inode *inode)
	92	{
91b0abe3	93	truncate_inode_pages_final(&inode->i_data);
19d87ca3	94	clear_inode(inode);
19d87ca3 BS	95	/* If we are holding a delegation, return it! */
19d87ca3 BS	96	nfs_inode_return_delegation_noreclaim(inode);
415320fc TM	97	/* Note that above delegreturn would trigger pnfs return-on-close */
	98	pnfs_return_layout(inode);
	99	pnfs_destroy_layout(NFS_I(inode));
19d87ca3 BS	100	/* First call standard NFS clear_inode() code */
	101	nfs_clear_inode(inode);
	102	}
	103
fbdefd64 BS	104	/*
	105	* Get the superblock for the NFS4 root partition
	106	*/
	107	static struct dentry *
	108	nfs4_remote_mount(struct file_system_type *fs_type, int flags,
	109	const char dev_name, void info)
	110	{
	111	struct nfs_mount_info *mount_info = info;
	112	struct nfs_server *server;
	113	struct dentry *mntroot = ERR_PTR(-ENOMEM);
	114
fbdefd64 BS	115	mount_info->set_security = nfs_set_sb_security;
	116
	117	/* Get a volume representation */
1179acc6	118	server = nfs4_create_server(mount_info, &nfs_v4);
fbdefd64 BS	119	if (IS_ERR(server)) {
	120	mntroot = ERR_CAST(server);
	121	goto out;
	122	}
	123
ab7017a3	124	mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4);
fbdefd64 BS	125
	126	out:
	127	return mntroot;
	128	}
	129
	130	static struct vfsmount nfs_do_root_mount(struct file_system_type fs_type,
	131	int flags, void data, const char hostname)
	132	{
	133	struct vfsmount *root_mnt;
	134	char *root_devname;
	135	size_t len;
	136
	137	len = strlen(hostname) + 5;
	138	root_devname = kmalloc(len, GFP_KERNEL);
	139	if (root_devname == NULL)
	140	return ERR_PTR(-ENOMEM);
	141	/* Does hostname needs to be enclosed in brackets? */
	142	if (strchr(hostname, ':'))
	143	snprintf(root_devname, len, "[%s]:/", hostname);
	144	else
	145	snprintf(root_devname, len, "%s:/", hostname);
	146	root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data);
	147	kfree(root_devname);
	148	return root_mnt;
	149	}
	150
	151	struct nfs_referral_count {
	152	struct list_head list;
	153	const struct task_struct *task;
	154	unsigned int referral_count;
	155	};
	156
	157	static LIST_HEAD(nfs_referral_count_list);
	158	static DEFINE_SPINLOCK(nfs_referral_count_list_lock);
	159
	160	static struct nfs_referral_count *nfs_find_referral_count(void)
	161	{
	162	struct nfs_referral_count *p;
	163
	164	list_for_each_entry(p, &nfs_referral_count_list, list) {
	165	if (p->task == current)
	166	return p;
	167	}
	168	return NULL;
	169	}
	170
	171	#define NFS_MAX_NESTED_REFERRALS 2
	172
	173	static int nfs_referral_loop_protect(void)
	174	{
	175	struct nfs_referral_count p, new;
	176	int ret = -ENOMEM;
	177
	178	new = kmalloc(sizeof(*new), GFP_KERNEL);
	179	if (!new)
	180	goto out;
	181	new->task = current;
	182	new->referral_count = 1;
	183
	184	ret = 0;
	185	spin_lock(&nfs_referral_count_list_lock);
	186	p = nfs_find_referral_count();
	187	if (p != NULL) {
	188	if (p->referral_count >= NFS_MAX_NESTED_REFERRALS)
189	ret = -ELOOP;
190	else
191	p->referral_count++;
192	} else {
193	list_add(&new->list, &nfs_referral_count_list);
194	new = NULL;
195	}
196	spin_unlock(&nfs_referral_count_list_lock);
197	kfree(new);
198	out:
199	return ret;
200	}
201
202	static void nfs_referral_loop_unprotect(void)
203	{
204	struct nfs_referral_count *p;
205
206	spin_lock(&nfs_referral_count_list_lock);
207	p = nfs_find_referral_count();
208	p->referral_count--;
209	if (p->referral_count == 0)
210	list_del(&p->list);
211	else
212	p = NULL;
213	spin_unlock(&nfs_referral_count_list_lock);
214	kfree(p);
215	}
216
217	static struct dentry nfs_follow_remote_path(struct vfsmount root_mnt,
218	const char *export_path)
219	{
220	struct dentry *dentry;
221	int err;
222
223	if (IS_ERR(root_mnt))
224	return ERR_CAST(root_mnt);
225
226	err = nfs_referral_loop_protect();
227	if (err) {
228	mntput(root_mnt);
229	return ERR_PTR(err);
230	}
231
232	dentry = mount_subtree(root_mnt, export_path);
233	nfs_referral_loop_unprotect();
234
235	return dentry;
236	}
237
238	struct dentry nfs4_try_mount(int flags, const char dev_name,
ff9099f2 BS	239	struct nfs_mount_info *mount_info,
ff9099f2 BS	240	struct nfs_subversion *nfs_mod)
fbdefd64 BS	241	{
	242	char *export_path;
	243	struct vfsmount *root_mnt;
	244	struct dentry *res;
	245	struct nfs_parsed_mount_data *data = mount_info->parsed;
	246
	247	dfprintk(MOUNT, "--> nfs4_try_mount()\n");
	248
fbdefd64 BS	249	export_path = data->nfs_server.export_path;
	250	data->nfs_server.export_path = "/";
	251	root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info,
	252	data->nfs_server.hostname);
	253	data->nfs_server.export_path = export_path;
	254
	255	res = nfs_follow_remote_path(root_mnt, export_path);
	256
6706246b GB	257	dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n",
	258	PTR_ERR_OR_ZERO(res),
	259	IS_ERR(res) ? " [error]" : "");
fbdefd64 BS	260	return res;
	261	}
	262
fbdefd64 BS	263	static struct dentry *
	264	nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags,
	265	const char dev_name, void raw_data)
	266	{
	267	struct nfs_mount_info mount_info = {
6a74490d	268	.fill_super = nfs_fill_super,
fbdefd64 BS	269	.set_security = nfs_clone_sb_security,
	270	.cloned = raw_data,
	271	};
	272	struct nfs_server *server;
	273	struct dentry *mntroot = ERR_PTR(-ENOMEM);
	274
	275	dprintk("--> nfs4_referral_get_sb()\n");
	276
	277	mount_info.mntfh = nfs_alloc_fhandle();
	278	if (mount_info.cloned == NULL \|\| mount_info.mntfh == NULL)
	279	goto out;
	280
	281	/* create a new volume representation */
	282	server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh);
	283	if (IS_ERR(server)) {
	284	mntroot = ERR_CAST(server);
	285	goto out;
	286	}
	287
ab7017a3	288	mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4);
fbdefd64 BS	289	out:
	290	nfs_free_fhandle(mount_info.mntfh);
	291	return mntroot;
	292	}
	293
	294	/*
	295	* Create an NFS4 server record on referral traversal
	296	*/
	297	static struct dentry nfs4_referral_mount(struct file_system_type fs_type,
	298	int flags, const char dev_name, void raw_data)
	299	{
	300	struct nfs_clone_mount *data = raw_data;
	301	char *export_path;
	302	struct vfsmount *root_mnt;
	303	struct dentry *res;
	304
	305	dprintk("--> nfs4_referral_mount()\n");
	306
	307	export_path = data->mnt_path;
	308	data->mnt_path = "/";
	309
	310	root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type,
	311	flags, data, data->hostname);
	312	data->mnt_path = export_path;
	313
	314	res = nfs_follow_remote_path(root_mnt, export_path);
6706246b GB	315	dprintk("<-- nfs4_referral_mount() = %d%s\n",
	316	PTR_ERR_OR_ZERO(res),
	317	IS_ERR(res) ? " [error]" : "");
fbdefd64 BS	318	return res;
	319	}
	320
	321
89d77c8f	322	static int __init init_nfs_v4(void)
129d1977 BS	323	{
	324	int err;
	325
c8d74d9b	326	err = nfs_dns_resolver_init();
129d1977 BS	327	if (err)
	328	goto out;
	329
c8d74d9b	330	err = nfs_idmap_init();
466bfe7f BS	331	if (err)
	332	goto out1;
	333
c8d74d9b TM	334	err = nfs4_register_sysctl();
	335	if (err)
	336	goto out2;
	337
ab7017a3	338	register_nfs_version(&nfs_v4);
129d1977	339	return 0;
c8d74d9b	340	out2:
466bfe7f	341	nfs_idmap_quit();
c8d74d9b TM	342	out1:
c8d74d9b TM	343	nfs_dns_resolver_destroy();
129d1977 BS	344	out:
	345	return err;
	346	}
	347
89d77c8f	348	static void __exit exit_nfs_v4(void)
129d1977	349	{
5f01d953 PT	350	/* Not called in the _init(), conditionally loaded */
	351	nfs4_pnfs_v3_ds_connect_unload();
	352
ab7017a3	353	unregister_nfs_version(&nfs_v4);
466bfe7f	354	nfs4_unregister_sysctl();
129d1977	355	nfs_idmap_quit();
c8d74d9b	356	nfs_dns_resolver_destroy();
129d1977	357	}
89d77c8f BS	358
	359	MODULE_LICENSE("GPL");
	360
	361	module_init(init_nfs_v4);
	362	module_exit(exit_nfs_v4);