[linux-block.git] / fs / nfs / namespace.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/fs/nfs/namespace.c
 *
 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
 * - Modified by David Howells <dhowells@redhat.com>
 *
 * NFS namespace
 */

#include <linux/module.h>
#include <linux/dcache.h>
#include <linux/gfp.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/nfs_fs.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
#include <linux/sunrpc/gss_api.h>
#include "internal.h"
#include "nfs.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

static void nfs_expire_automounts(struct work_struct *work);

static LIST_HEAD(nfs_automount_list);
static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
int nfs_mountpoint_expiry_timeout = 500 * HZ;

/*
 * nfs_path - reconstruct the path given an arbitrary dentry
 * @base - used to return pointer to the end of devname part of path
 * @dentry - pointer to dentry
 * @buffer - result buffer
 * @buflen - length of buffer
 * @flags - options (see below)
 *
 * Helper function for constructing the server pathname
 * by arbitrary hashed dentry.
 *
 * This is mainly for use in figuring out the path on the
 * server side when automounting on top of an existing partition
 * and in generating /proc/mounts and friends.
 *
 * Supported flags:
 * NFS_PATH_CANONICAL: ensure there is exactly one slash after
 *		       the original device (export) name
 *		       (if unset, the original name is returned verbatim)
 */
char *nfs_path(char **p, struct dentry *dentry, char *buffer, ssize_t buflen,
	       unsigned flags)
{
	char *end;
	int namelen;
	unsigned seq;
	const char *base;

rename_retry:
	end = buffer+buflen;
	*--end = '\0';
	buflen--;

	seq = read_seqbegin(&rename_lock);
	rcu_read_lock();
	while (1) {
		spin_lock(&dentry->d_lock);
		if (IS_ROOT(dentry))
			break;
		namelen = dentry->d_name.len;
		buflen -= namelen + 1;
		if (buflen < 0)
			goto Elong_unlock;
		end -= namelen;
		memcpy(end, dentry->d_name.name, namelen);
		*--end = '/';
		spin_unlock(&dentry->d_lock);
		dentry = dentry->d_parent;
	}
	if (read_seqretry(&rename_lock, seq)) {
		spin_unlock(&dentry->d_lock);
		rcu_read_unlock();
		goto rename_retry;
	}
	if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
		if (--buflen < 0) {
			spin_unlock(&dentry->d_lock);
			rcu_read_unlock();
			goto Elong;
		}
		*--end = '/';
	}
	*p = end;
	base = dentry->d_fsdata;
	if (!base) {
		spin_unlock(&dentry->d_lock);
		rcu_read_unlock();
		WARN_ON(1);
		return end;
	}
	namelen = strlen(base);
	if (*end == '/') {
		/* Strip off excess slashes in base string */
		while (namelen > 0 && base[namelen - 1] == '/')
			namelen--;
	}
	buflen -= namelen;
	if (buflen < 0) {
		spin_unlock(&dentry->d_lock);
		rcu_read_unlock();
		goto Elong;
	}
	end -= namelen;
	memcpy(end, base, namelen);
	spin_unlock(&dentry->d_lock);
	rcu_read_unlock();
	return end;
Elong_unlock:
	spin_unlock(&dentry->d_lock);
	rcu_read_unlock();
	if (read_seqretry(&rename_lock, seq))
		goto rename_retry;
Elong:
	return ERR_PTR(-ENAMETOOLONG);
}
EXPORT_SYMBOL_GPL(nfs_path);

/*
 * nfs_d_automount - Handle crossing a mountpoint on the server
 * @path - The mountpoint
 *
 * When we encounter a mountpoint on the server, we want to set up
 * a mountpoint on the client too, to prevent inode numbers from
 * colliding, and to allow "df" to work properly.
 * On NFSv4, we also want to allow for the fact that different
 * filesystems may be migrated to different servers in a failover
 * situation, and that different filesystems may want to use
 * different security flavours.
 */
struct vfsmount *nfs_d_automount(struct path *path)
{
	struct nfs_fs_context *ctx;
	struct fs_context *fc;
	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
	struct nfs_server *server = NFS_SERVER(d_inode(path->dentry));
	struct nfs_client *client = server->nfs_client;
	int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout);
	int ret;

	if (IS_ROOT(path->dentry))
		return ERR_PTR(-ESTALE);

	/* Open a new filesystem context, transferring parameters from the
	 * parent superblock, including the network namespace.
	 */
	fc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry);
	if (IS_ERR(fc))
		return ERR_CAST(fc);

	ctx = nfs_fc2context(fc);
	ctx->clone_data.dentry	= path->dentry;
	ctx->clone_data.sb	= path->dentry->d_sb;
	ctx->clone_data.fattr	= nfs_alloc_fattr();
	if (!ctx->clone_data.fattr)
		goto out_fc;

	if (fc->net_ns != client->cl_net) {
		put_net(fc->net_ns);
		fc->net_ns = get_net(client->cl_net);
	}

	/* for submounts we want the same server; referrals will reassign */
	memcpy(&ctx->nfs_server.address, &client->cl_addr, client->cl_addrlen);
	ctx->nfs_server.addrlen	= client->cl_addrlen;
	ctx->nfs_server.port	= server->port;

	ctx->version		= client->rpc_ops->version;
	ctx->minorversion	= client->cl_minorversion;
	ctx->nfs_mod		= client->cl_nfs_mod;
	__module_get(ctx->nfs_mod->owner);

	ret = client->rpc_ops->submount(fc, server);
	if (ret < 0) {
		mnt = ERR_PTR(ret);
		goto out_fc;
	}

	up_write(&fc->root->d_sb->s_umount);
	mnt = vfs_create_mount(fc);
	if (IS_ERR(mnt))
		goto out_fc;

	mntget(mnt); /* prevent immediate expiration */
	if (timeout <= 0)
		goto out_fc;

	mnt_set_expiry(mnt, &nfs_automount_list);
	schedule_delayed_work(&nfs_automount_task, timeout);

out_fc:
	put_fs_context(fc);
	return mnt;
}

static int
nfs_namespace_getattr(const struct path *path, struct kstat *stat,
			u32 request_mask, unsigned int query_flags)
{
	if (NFS_FH(d_inode(path->dentry))->size != 0)
		return nfs_getattr(path, stat, request_mask, query_flags);
	generic_fillattr(d_inode(path->dentry), stat);
	return 0;
}

static int
nfs_namespace_setattr(struct dentry *dentry, struct iattr *attr)
{
	if (NFS_FH(d_inode(dentry))->size != 0)
		return nfs_setattr(dentry, attr);
	return -EACCES;
}

const struct inode_operations nfs_mountpoint_inode_operations = {
	.getattr	= nfs_getattr,
	.setattr	= nfs_setattr,
};

const struct inode_operations nfs_referral_inode_operations = {
	.getattr	= nfs_namespace_getattr,
	.setattr	= nfs_namespace_setattr,
};

static void nfs_expire_automounts(struct work_struct *work)
{
	struct list_head *list = &nfs_automount_list;
	int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout);

	mark_mounts_for_expiry(list);
	if (!list_empty(list) && timeout > 0)
		schedule_delayed_work(&nfs_automount_task, timeout);
}

void nfs_release_automount_timer(void)
{
	if (list_empty(&nfs_automount_list))
		cancel_delayed_work(&nfs_automount_task);
}

/**
 * nfs_do_submount - set up mountpoint when crossing a filesystem boundary
 * @fc: pointer to struct nfs_fs_context
 *
 */
int nfs_do_submount(struct fs_context *fc)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	struct dentry *dentry = ctx->clone_data.dentry;
	struct nfs_server *server;
	char *buffer, *p;
	int ret;

	/* create a new volume representation */
	server = ctx->nfs_mod->rpc_ops->clone_server(NFS_SB(ctx->clone_data.sb),
						     ctx->mntfh,
						     ctx->clone_data.fattr,
						     ctx->selected_flavor);

	if (IS_ERR(server))
		return PTR_ERR(server);

	ctx->server = server;

	buffer = kmalloc(4096, GFP_USER);
	if (!buffer)
		return -ENOMEM;

	ctx->internal		= true;
	ctx->clone_data.inherited_bsize = ctx->clone_data.sb->s_blocksize_bits;

	p = nfs_devname(dentry, buffer, 4096);
	if (IS_ERR(p)) {
		nfs_errorf(fc, "NFS: Couldn't determine submount pathname");
		ret = PTR_ERR(p);
	} else {
		ret = vfs_parse_fs_string(fc, "source", p, buffer + 4096 - p);
		if (!ret)
			ret = vfs_get_tree(fc);
	}
	kfree(buffer);
	return ret;
}
EXPORT_SYMBOL_GPL(nfs_do_submount);

int nfs_submount(struct fs_context *fc, struct nfs_server *server)
{
	struct nfs_fs_context *ctx = nfs_fc2context(fc);
	struct dentry *dentry = ctx->clone_data.dentry;
	struct dentry *parent = dget_parent(dentry);
	int err;

	/* Look it up again to get its attributes */
	err = server->nfs_client->rpc_ops->lookup(d_inode(parent), dentry,
						  ctx->mntfh, ctx->clone_data.fattr,
						  NULL);
	dput(parent);
	if (err != 0)
		return err;

	ctx->selected_flavor = server->client->cl_auth->au_flavor;
	return nfs_do_submount(fc);
}
EXPORT_SYMBOL_GPL(nfs_submount);

static int param_set_nfs_timeout(const char *val, const struct kernel_param *kp)
{
	long num;
	int ret;

	if (!val)
		return -EINVAL;
	ret = kstrtol(val, 0, &num);
	if (ret)
		return -EINVAL;
	if (num > 0) {
		if (num >= INT_MAX / HZ)
			num = INT_MAX;
		else
			num *= HZ;
		*((int *)kp->arg) = num;
		if (!list_empty(&nfs_automount_list))
			mod_delayed_work(system_wq, &nfs_automount_task, num);
	} else {
		*((int *)kp->arg) = -1*HZ;
		cancel_delayed_work(&nfs_automount_task);
	}
	return 0;
}

static int param_get_nfs_timeout(char *buffer, const struct kernel_param *kp)
{
	long num = *((int *)kp->arg);

	if (num > 0) {
		if (num >= INT_MAX - (HZ - 1))
			num = INT_MAX / HZ;
		else
			num = (num + (HZ - 1)) / HZ;
	} else
		num = -1;
	return scnprintf(buffer, PAGE_SIZE, "%li\n", num);
}

static const struct kernel_param_ops param_ops_nfs_timeout = {
	.set = param_set_nfs_timeout,
	.get = param_get_nfs_timeout,
};
#define param_check_nfs_timeout(name, p) __param_check(name, p, int);

module_param(nfs_mountpoint_expiry_timeout, nfs_timeout, 0644);
MODULE_PARM_DESC(nfs_mountpoint_expiry_timeout,
		"Set the NFS automounted mountpoint timeout value (seconds)."
		"Values <= 0 turn expiration off.");
Commit	Line	Data
457c8996	1	// SPDX-License-Identifier: GPL-2.0-only
55a97593 TM	2	/*
	3	* linux/fs/nfs/namespace.c
	4	*
	5	* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
54ceac45	6	* - Modified by David Howells <dhowells@redhat.com>
55a97593 TM	7	*
	8	* NFS namespace
	9	*/
	10
ddda8e0a	11	#include <linux/module.h>
55a97593	12	#include <linux/dcache.h>
5a0e3ad6	13	#include <linux/gfp.h>
55a97593 TM	14	#include <linux/mount.h>
	15	#include <linux/namei.h>
	16	#include <linux/nfs_fs.h>
	17	#include <linux/string.h>
	18	#include <linux/sunrpc/clnt.h>
	19	#include <linux/vfs.h>
7ebb9315	20	#include <linux/sunrpc/gss_api.h>
f7b422b1	21	#include "internal.h"
250d69f6	22	#include "nfs.h"
55a97593 TM	23
	24	#define NFSDBG_FACILITY NFSDBG_VFS
	25
65f27f38	26	static void nfs_expire_automounts(struct work_struct *work);
f7b422b1	27
a3dab293	28	static LIST_HEAD(nfs_automount_list);
65f27f38	29	static DECLARE_DELAYED_WORK(nfs_automount_task, nfs_expire_automounts);
51d8fa6a TM	30	int nfs_mountpoint_expiry_timeout = 500 * HZ;
51d8fa6a TM	31
f7b422b1 DH	32	/*
f7b422b1 DH	33	* nfs_path - reconstruct the path given an arbitrary dentry
b514f872	34	* @base - used to return pointer to the end of devname part of path
f7b422b1 DH	35	* @dentry - pointer to dentry
	36	* @buffer - result buffer
	37	* @buflen - length of buffer
97a54868	38	* @flags - options (see below)
f7b422b1	39	*
b514f872 AV	40	* Helper function for constructing the server pathname
b514f872 AV	41	* by arbitrary hashed dentry.
f7b422b1 DH	42	*
f7b422b1 DH	43	* This is mainly for use in figuring out the path on the
b514f872 AV	44	* server side when automounting on top of an existing partition
b514f872 AV	45	* and in generating /proc/mounts and friends.
97a54868 BH	46	*
	47	* Supported flags:
	48	* NFS_PATH_CANONICAL: ensure there is exactly one slash after
	49	* the original device (export) name
	50	* (if unset, the original name is returned verbatim)
f7b422b1	51	*/
97a54868 BH	52	char nfs_path(char p, struct dentry dentry, char *buffer, ssize_t buflen,
97a54868 BH	53	unsigned flags)
f7b422b1	54	{
949854d0	55	char *end;
f7b422b1	56	int namelen;
949854d0	57	unsigned seq;
b514f872	58	const char *base;
f7b422b1	59
949854d0 NP	60	rename_retry:
949854d0 NP	61	end = buffer+buflen;
f7b422b1 DH	62	*--end = '\0';
f7b422b1 DH	63	buflen--;
949854d0 NP	64
	65	seq = read_seqbegin(&rename_lock);
	66	rcu_read_lock();
b514f872 AV	67	while (1) {
	68	spin_lock(&dentry->d_lock);
	69	if (IS_ROOT(dentry))
	70	break;
f7b422b1 DH	71	namelen = dentry->d_name.len;
	72	buflen -= namelen + 1;
	73	if (buflen < 0)
ce510193	74	goto Elong_unlock;
f7b422b1 DH	75	end -= namelen;
	76	memcpy(end, dentry->d_name.name, namelen);
	77	*--end = '/';
b514f872	78	spin_unlock(&dentry->d_lock);
f7b422b1 DH	79	dentry = dentry->d_parent;
f7b422b1 DH	80	}
b514f872 AV	81	if (read_seqretry(&rename_lock, seq)) {
	82	spin_unlock(&dentry->d_lock);
	83	rcu_read_unlock();
949854d0	84	goto rename_retry;
b514f872	85	}
97a54868	86	if ((flags & NFS_PATH_CANONICAL) && *end != '/') {
b514f872 AV	87	if (--buflen < 0) {
	88	spin_unlock(&dentry->d_lock);
	89	rcu_read_unlock();
0b75b35c	90	goto Elong;
b514f872	91	}
0b75b35c TM	92	*--end = '/';
0b75b35c TM	93	}
b514f872 AV	94	*p = end;
	95	base = dentry->d_fsdata;
	96	if (!base) {
	97	spin_unlock(&dentry->d_lock);
	98	rcu_read_unlock();
	99	WARN_ON(1);
	100	return end;
	101	}
f7b422b1	102	namelen = strlen(base);
86a6c211	103	if (*end == '/') {
97a54868 BH	104	/* Strip off excess slashes in base string */
	105	while (namelen > 0 && base[namelen - 1] == '/')
	106	namelen--;
	107	}
f7b422b1	108	buflen -= namelen;
b514f872	109	if (buflen < 0) {
1c34092a	110	spin_unlock(&dentry->d_lock);
b514f872	111	rcu_read_unlock();
f7b422b1	112	goto Elong;
b514f872	113	}
f7b422b1 DH	114	end -= namelen;
f7b422b1 DH	115	memcpy(end, base, namelen);
b514f872 AV	116	spin_unlock(&dentry->d_lock);
b514f872 AV	117	rcu_read_unlock();
f7b422b1	118	return end;
ce510193	119	Elong_unlock:
1c34092a	120	spin_unlock(&dentry->d_lock);
949854d0 NP	121	rcu_read_unlock();
	122	if (read_seqretry(&rename_lock, seq))
	123	goto rename_retry;
f7b422b1 DH	124	Elong:
	125	return ERR_PTR(-ENAMETOOLONG);
	126	}
89d77c8f	127	EXPORT_SYMBOL_GPL(nfs_path);
f7b422b1	128
55a97593	129	/*
36d43a43 DH	130	* nfs_d_automount - Handle crossing a mountpoint on the server
36d43a43 DH	131	* @path - The mountpoint
55a97593 TM	132	*
	133	* When we encounter a mountpoint on the server, we want to set up
	134	* a mountpoint on the client too, to prevent inode numbers from
	135	* colliding, and to allow "df" to work properly.
	136	* On NFSv4, we also want to allow for the fact that different
	137	* filesystems may be migrated to different servers in a failover
	138	* situation, and that different filesystems may want to use
	139	* different security flavours.
	140	*/
36d43a43	141	struct vfsmount nfs_d_automount(struct path path)
55a97593	142	{
f2aedb71 DH	143	struct nfs_fs_context *ctx;
	144	struct fs_context *fc;
	145	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
2b0143b5	146	struct nfs_server *server = NFS_SERVER(d_inode(path->dentry));
f2aedb71	147	struct nfs_client *client = server->nfs_client;
75da9858	148	int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout);
f2aedb71	149	int ret;
55a97593	150
36d43a43	151	if (IS_ROOT(path->dentry))
e36d48e9	152	return ERR_PTR(-ESTALE);
44d5759d	153
f2aedb71 DH	154	/* Open a new filesystem context, transferring parameters from the
	155	* parent superblock, including the network namespace.
	156	*/
1821b26a	157	fc = fs_context_for_submount(path->mnt->mnt_sb->s_type, path->dentry);
f2aedb71 DH	158	if (IS_ERR(fc))
f2aedb71 DH	159	return ERR_CAST(fc);
a4d7f168	160
f2aedb71 DH	161	ctx = nfs_fc2context(fc);
	162	ctx->clone_data.dentry = path->dentry;
	163	ctx->clone_data.sb = path->dentry->d_sb;
	164	ctx->clone_data.fattr = nfs_alloc_fattr();
	165	if (!ctx->clone_data.fattr)
	166	goto out_fc;
	167
	168	if (fc->net_ns != client->cl_net) {
	169	put_net(fc->net_ns);
	170	fc->net_ns = get_net(client->cl_net);
	171	}
	172
	173	/* for submounts we want the same server; referrals will reassign */
	174	memcpy(&ctx->nfs_server.address, &client->cl_addr, client->cl_addrlen);
	175	ctx->nfs_server.addrlen = client->cl_addrlen;
	176	ctx->nfs_server.port = server->port;
	177
	178	ctx->version = client->rpc_ops->version;
	179	ctx->minorversion = client->cl_minorversion;
62a55d08 SM	180	ctx->nfs_mod = client->cl_nfs_mod;
62a55d08 SM	181	__module_get(ctx->nfs_mod->owner);
f2aedb71 DH	182
	183	ret = client->rpc_ops->submount(fc, server);
	184	if (ret < 0) {
	185	mnt = ERR_PTR(ret);
	186	goto out_fc;
	187	}
	188
	189	up_write(&fc->root->d_sb->s_umount);
	190	mnt = vfs_create_mount(fc);
55a97593	191	if (IS_ERR(mnt))
f2aedb71	192	goto out_fc;
55a97593	193
75da9858 TM	194	mntget(mnt); /* prevent immediate expiration */
75da9858 TM	195	if (timeout <= 0)
f2aedb71	196	goto out_fc;
22a1ae9a	197
ea5b778a	198	mnt_set_expiry(mnt, &nfs_automount_list);
75da9858	199	schedule_delayed_work(&nfs_automount_task, timeout);
36d43a43	200
f2aedb71 DH	201	out_fc:
f2aedb71 DH	202	put_fs_context(fc);
36d43a43	203	return mnt;
55a97593 TM	204	}
55a97593 TM	205
ab225417	206	static int
a528d35e DH	207	nfs_namespace_getattr(const struct path path, struct kstat stat,
a528d35e DH	208	u32 request_mask, unsigned int query_flags)
ab225417	209	{
a528d35e DH	210	if (NFS_FH(d_inode(path->dentry))->size != 0)
	211	return nfs_getattr(path, stat, request_mask, query_flags);
	212	generic_fillattr(d_inode(path->dentry), stat);
ab225417 TM	213	return 0;
	214	}
	215
	216	static int
	217	nfs_namespace_setattr(struct dentry dentry, struct iattr attr)
	218	{
2b0143b5	219	if (NFS_FH(d_inode(dentry))->size != 0)
ab225417 TM	220	return nfs_setattr(dentry, attr);
	221	return -EACCES;
	222	}
	223
92e1d5be	224	const struct inode_operations nfs_mountpoint_inode_operations = {
55a97593	225	.getattr = nfs_getattr,
ab225417	226	.setattr = nfs_setattr,
55a97593	227	};
51d8fa6a	228
92e1d5be	229	const struct inode_operations nfs_referral_inode_operations = {
ab225417 TM	230	.getattr = nfs_namespace_getattr,
ab225417 TM	231	.setattr = nfs_namespace_setattr,
6b97fd3d MN	232	};
6b97fd3d MN	233
65f27f38	234	static void nfs_expire_automounts(struct work_struct *work)
51d8fa6a	235	{
65f27f38	236	struct list_head *list = &nfs_automount_list;
75da9858	237	int timeout = READ_ONCE(nfs_mountpoint_expiry_timeout);
51d8fa6a TM	238
51d8fa6a TM	239	mark_mounts_for_expiry(list);
75da9858 TM	240	if (!list_empty(list) && timeout > 0)
75da9858 TM	241	schedule_delayed_work(&nfs_automount_task, timeout);
51d8fa6a TM	242	}
	243
	244	void nfs_release_automount_timer(void)
	245	{
3d39c691	246	if (list_empty(&nfs_automount_list))
560aef74	247	cancel_delayed_work(&nfs_automount_task);
51d8fa6a	248	}
f7b422b1	249
f7b422b1 DH	250	/**
f7b422b1 DH	251	* nfs_do_submount - set up mountpoint when crossing a filesystem boundary
3cab1854	252	* @fc: pointer to struct nfs_fs_context
f7b422b1 DH	253	*
f7b422b1 DH	254	*/
f2aedb71	255	int nfs_do_submount(struct fs_context *fc)
f7b422b1	256	{
f2aedb71 DH	257	struct nfs_fs_context *ctx = nfs_fc2context(fc);
f2aedb71 DH	258	struct dentry *dentry = ctx->clone_data.dentry;
250d69f6	259	struct nfs_server *server;
f2aedb71 DH	260	char buffer, p;
f2aedb71 DH	261	int ret;
f7b422b1	262
f2aedb71	263	/* create a new volume representation */
62a55d08 SM	264	server = ctx->nfs_mod->rpc_ops->clone_server(NFS_SB(ctx->clone_data.sb),
62a55d08 SM	265	ctx->mntfh,
f2aedb71 DH	266	ctx->clone_data.fattr,
f2aedb71 DH	267	ctx->selected_flavor);
e36d48e9	268
250d69f6	269	if (IS_ERR(server))
f2aedb71	270	return PTR_ERR(server);
250d69f6	271
62a55d08	272	ctx->server = server;
250d69f6	273
f2aedb71 DH	274	buffer = kmalloc(4096, GFP_USER);
	275	if (!buffer)
	276	return -ENOMEM;
54ceac45	277
f2aedb71	278	ctx->internal = true;
62a55d08	279	ctx->clone_data.inherited_bsize = ctx->clone_data.sb->s_blocksize_bits;
f2aedb71 DH	280
	281	p = nfs_devname(dentry, buffer, 4096);
	282	if (IS_ERR(p)) {
ce8866f0	283	nfs_errorf(fc, "NFS: Couldn't determine submount pathname");
f2aedb71 DH	284	ret = PTR_ERR(p);
	285	} else {
	286	ret = vfs_parse_fs_string(fc, "source", p, buffer + 4096 - p);
	287	if (!ret)
	288	ret = vfs_get_tree(fc);
	289	}
	290	kfree(buffer);
	291	return ret;
f7b422b1	292	}
89d77c8f	293	EXPORT_SYMBOL_GPL(nfs_do_submount);
281cad46	294
f2aedb71	295	int nfs_submount(struct fs_context fc, struct nfs_server server)
281cad46	296	{
f2aedb71 DH	297	struct nfs_fs_context *ctx = nfs_fc2context(fc);
f2aedb71 DH	298	struct dentry *dentry = ctx->clone_data.dentry;
281cad46	299	struct dentry *parent = dget_parent(dentry);
f2aedb71	300	int err;
281cad46 BS	301
281cad46 BS	302	/* Look it up again to get its attributes */
f7b37b8b	303	err = server->nfs_client->rpc_ops->lookup(d_inode(parent), dentry,
62a55d08	304	ctx->mntfh, ctx->clone_data.fattr,
f2aedb71	305	NULL);
281cad46 BS	306	dput(parent);
281cad46 BS	307	if (err != 0)
f2aedb71	308	return err;
281cad46	309
f2aedb71 DH	310	ctx->selected_flavor = server->client->cl_auth->au_flavor;
f2aedb71 DH	311	return nfs_do_submount(fc);
281cad46	312	}
ddda8e0a	313	EXPORT_SYMBOL_GPL(nfs_submount);
f30a6ea0 TM	314
	315	static int param_set_nfs_timeout(const char val, const struct kernel_param kp)
	316	{
	317	long num;
	318	int ret;
	319
	320	if (!val)
	321	return -EINVAL;
	322	ret = kstrtol(val, 0, &num);
	323	if (ret)
	324	return -EINVAL;
	325	if (num > 0) {
	326	if (num >= INT_MAX / HZ)
	327	num = INT_MAX;
	328	else
	329	num *= HZ;
	330	((int )kp->arg) = num;
	331	if (!list_empty(&nfs_automount_list))
	332	mod_delayed_work(system_wq, &nfs_automount_task, num);
	333	} else {
	334	((int )kp->arg) = -1*HZ;
	335	cancel_delayed_work(&nfs_automount_task);
	336	}
	337	return 0;
	338	}
	339
	340	static int param_get_nfs_timeout(char buffer, const struct kernel_param kp)
	341	{
	342	long num = ((int )kp->arg);
	343
	344	if (num > 0) {
	345	if (num >= INT_MAX - (HZ - 1))
	346	num = INT_MAX / HZ;
	347	else
	348	num = (num + (HZ - 1)) / HZ;
	349	} else
	350	num = -1;
	351	return scnprintf(buffer, PAGE_SIZE, "%li\n", num);
	352	}
	353
	354	static const struct kernel_param_ops param_ops_nfs_timeout = {
	355	.set = param_set_nfs_timeout,
	356	.get = param_get_nfs_timeout,
	357	};
	358	#define param_check_nfs_timeout(name, p) __param_check(name, p, int);
	359
	360	module_param(nfs_mountpoint_expiry_timeout, nfs_timeout, 0644);
	361	MODULE_PARM_DESC(nfs_mountpoint_expiry_timeout,
	362	"Set the NFS automounted mountpoint timeout value (seconds)."
	363	"Values <= 0 turn expiration off.");