[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / nfs / nfs4namespace.c

/*
 * linux/fs/nfs/nfs4namespace.c
 *
 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
 * - Modified by David Howells <dhowells@redhat.com>
 *
 * NFSv4 namespace
 */

#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/nfs_fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include "internal.h"
#include "nfs4_fs.h"
#include "dns_resolve.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

/*
 * Convert the NFSv4 pathname components into a standard posix path.
 *
 * Note that the resulting string will be placed at the end of the buffer
 */
static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
					 char *buffer, ssize_t buflen)
{
	char *end = buffer + buflen;
	int n;

	*--end = '\0';
	buflen--;

	n = pathname->ncomponents;
	while (--n >= 0) {
		const struct nfs4_string *component = &pathname->components[n];
		buflen -= component->len + 1;
		if (buflen < 0)
			goto Elong;
		end -= component->len;
		memcpy(end, component->data, component->len);
		*--end = '/';
	}
	return end;
Elong:
	return ERR_PTR(-ENAMETOOLONG);
}

/*
 * return the path component of "<server>:<path>"
 *  nfspath - the "<server>:<path>" string
 *  end - one past the last char that could contain "<server>:"
 * returns NULL on failure
 */
static char *nfs_path_component(const char *nfspath, const char *end)
{
	char *p;

	if (*nfspath == '[') {
		/* parse [] escaped IPv6 addrs */
		p = strchr(nfspath, ']');
		if (p != NULL && ++p < end && *p == ':')
			return p + 1;
	} else {
		/* otherwise split on first colon */
		p = strchr(nfspath, ':');
		if (p != NULL && p < end)
			return p + 1;
	}
	return NULL;
}

/*
 * Determine the mount path as a string
 */
static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
{
	char *limit;
	char *path = nfs_path(&limit, dentry, buffer, buflen,
			      NFS_PATH_CANONICAL);
	if (!IS_ERR(path)) {
		char *path_component = nfs_path_component(path, limit);
		if (path_component)
			return path_component;
	}
	return path;
}

/*
 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
 * believe to be the server path to this dentry
 */
static int nfs4_validate_fspath(struct dentry *dentry,
				const struct nfs4_fs_locations *locations,
				char *page, char *page2)
{
	const char *path, *fs_path;

	path = nfs4_path(dentry, page, PAGE_SIZE);
	if (IS_ERR(path))
		return PTR_ERR(path);

	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	if (IS_ERR(fs_path))
		return PTR_ERR(fs_path);

	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
		dprintk("%s: path %s does not begin with fsroot %s\n",
			__func__, path, fs_path);
		return -ENOENT;
	}

	return 0;
}

static size_t nfs_parse_server_name(char *string, size_t len,
		struct sockaddr *sa, size_t salen, struct nfs_server *server)
{
	struct net *net = rpc_net_ns(server->client);
	ssize_t ret;

	ret = rpc_pton(net, string, len, sa, salen);
	if (ret == 0) {
		ret = nfs_dns_resolve_name(net, string, len, sa, salen);
		if (ret < 0)
			ret = 0;
	}
	return ret;
}

/**
 * nfs_find_best_sec - Find a security mechanism supported locally
 * @flavors: List of security tuples returned by SECINFO procedure
 *
 * Return the pseudoflavor of the first security mechanism in
 * "flavors" that is locally supported.  Return RPC_AUTH_UNIX if
 * no matching flavor is found in the array.  The "flavors" array
 * is searched in the order returned from the server, per RFC 3530
 * recommendation.
 */
rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
{
	rpc_authflavor_t pseudoflavor;
	struct nfs4_secinfo4 *secinfo;
	unsigned int i;

	for (i = 0; i < flavors->num_flavors; i++) {
		secinfo = &flavors->flavors[i];

		switch (secinfo->flavor) {
		case RPC_AUTH_NULL:
		case RPC_AUTH_UNIX:
		case RPC_AUTH_GSS:
			pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
							&secinfo->flavor_info);
			if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
				return pseudoflavor;
			break;
		}
	}

	return RPC_AUTH_UNIX;
}

static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name)
{
	struct page *page;
	struct nfs4_secinfo_flavors *flavors;
	rpc_authflavor_t flavor;
	int err;

	page = alloc_page(GFP_KERNEL);
	if (!page)
		return -ENOMEM;
	flavors = page_address(page);

	err = nfs4_proc_secinfo(inode, name, flavors);
	if (err < 0) {
		flavor = err;
		goto out;
	}

	flavor = nfs_find_best_sec(flavors);

out:
	put_page(page);
	return flavor;
}

/*
 * Please call rpc_shutdown_client() when you are done with this client.
 */
struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode,
					struct qstr *name)
{
	rpc_authflavor_t flavor;

	flavor = nfs4_negotiate_security(inode, name);
	if ((int)flavor < 0)
		return ERR_PTR((int)flavor);

	return rpc_clone_client_set_auth(clnt, flavor);
}

static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
				     char *page, char *page2,
				     const struct nfs4_fs_location *location)
{
	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	char *mnt_path;
	unsigned int maxbuflen;
	unsigned int s;

	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	if (IS_ERR(mnt_path))
		return ERR_CAST(mnt_path);
	mountdata->mnt_path = mnt_path;
	maxbuflen = mnt_path - 1 - page2;

	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	if (mountdata->addr == NULL)
		return ERR_PTR(-ENOMEM);

	for (s = 0; s < location->nservers; s++) {
		const struct nfs4_string *buf = &location->servers[s];

		if (buf->len <= 0 || buf->len >= maxbuflen)
			continue;

		if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
			continue;

		mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
				mountdata->addr, addr_bufsize,
				NFS_SB(mountdata->sb));
		if (mountdata->addrlen == 0)
			continue;

		rpc_set_port(mountdata->addr, NFS_PORT);

		memcpy(page2, buf->data, buf->len);
		page2[buf->len] = '\0';
		mountdata->hostname = page2;

		snprintf(page, PAGE_SIZE, "%s:%s",
				mountdata->hostname,
				mountdata->mnt_path);

		mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
		if (!IS_ERR(mnt))
			break;
	}
	kfree(mountdata->addr);
	return mnt;
}

/**
 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
 * @dentry - parent directory
 * @locations - array of NFSv4 server location information
 *
 */
static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
					    const struct nfs4_fs_locations *locations)
{
	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	struct nfs_clone_mount mountdata = {
		.sb = dentry->d_sb,
		.dentry = dentry,
		.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
	};
	char *page = NULL, *page2 = NULL;
	int loc, error;

	if (locations == NULL || locations->nlocations <= 0)
		goto out;

	dprintk("%s: referral at %s/%s\n", __func__,
		dentry->d_parent->d_name.name, dentry->d_name.name);

	page = (char *) __get_free_page(GFP_USER);
	if (!page)
		goto out;

	page2 = (char *) __get_free_page(GFP_USER);
	if (!page2)
		goto out;

	/* Ensure fs path is a prefix of current dentry path */
	error = nfs4_validate_fspath(dentry, locations, page, page2);
	if (error < 0) {
		mnt = ERR_PTR(error);
		goto out;
	}

	for (loc = 0; loc < locations->nlocations; loc++) {
		const struct nfs4_fs_location *location = &locations->locations[loc];

		if (location == NULL || location->nservers <= 0 ||
		    location->rootpath.ncomponents == 0)
			continue;

		mnt = try_location(&mountdata, page, page2, location);
		if (!IS_ERR(mnt))
			break;
	}

out:
	free_page((unsigned long) page);
	free_page((unsigned long) page2);
	dprintk("%s: done\n", __func__);
	return mnt;
}

/*
 * nfs_do_refmount - handle crossing a referral on server
 * @dentry - dentry of referral
 *
 */
static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
{
	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
	struct dentry *parent;
	struct nfs4_fs_locations *fs_locations = NULL;
	struct page *page;
	int err;

	/* BUG_ON(IS_ROOT(dentry)); */
	dprintk("%s: enter\n", __func__);

	page = alloc_page(GFP_KERNEL);
	if (page == NULL)
		goto out;

	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	if (fs_locations == NULL)
		goto out_free;

	/* Get locations */
	mnt = ERR_PTR(-ENOENT);

	parent = dget_parent(dentry);
	dprintk("%s: getting locations for %s/%s\n",
		__func__, parent->d_name.name, dentry->d_name.name);

	err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
	dput(parent);
	if (err != 0 ||
	    fs_locations->nlocations <= 0 ||
	    fs_locations->fs_path.ncomponents <= 0)
		goto out_free;

	mnt = nfs_follow_referral(dentry, fs_locations);
out_free:
	__free_page(page);
	kfree(fs_locations);
out:
	dprintk("%s: done\n", __func__);
	return mnt;
}

struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
			       struct nfs_fh *fh, struct nfs_fattr *fattr)
{
	struct dentry *parent = dget_parent(dentry);
	struct rpc_clnt *client;
	struct vfsmount *mnt;

	/* Look it up again to get its attributes and sec flavor */
	client = nfs4_proc_lookup_mountpoint(parent->d_inode, &dentry->d_name, fh, fattr);
	dput(parent);
	if (IS_ERR(client))
		return ERR_CAST(client);

	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
		mnt = nfs_do_refmount(client, dentry);
	else
		mnt = nfs_do_submount(dentry, fh, fattr, client->cl_auth->au_flavor);

	rpc_shutdown_client(client);
	return mnt;
}
Commit	Line	Data
f7b422b1 DH	1	/*
	2	* linux/fs/nfs/nfs4namespace.c
	3	*
	4	* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
54ceac45	5	* - Modified by David Howells <dhowells@redhat.com>
f7b422b1 DH	6	*
	7	* NFSv4 namespace
	8	*/
	9
f7b422b1 DH	10	#include <linux/dcache.h>
	11	#include <linux/mount.h>
	12	#include <linux/namei.h>
	13	#include <linux/nfs_fs.h>
5a0e3ad6	14	#include <linux/slab.h>
f7b422b1 DH	15	#include <linux/string.h>
f7b422b1 DH	16	#include <linux/sunrpc/clnt.h>
5976687a	17	#include <linux/sunrpc/addr.h>
f7b422b1 DH	18	#include <linux/vfs.h>
	19	#include <linux/inet.h>
	20	#include "internal.h"
c228fd3a	21	#include "nfs4_fs.h"
7d7ea882	22	#include "dns_resolve.h"
f7b422b1 DH	23
	24	#define NFSDBG_FACILITY NFSDBG_VFS
	25
	26	/*
ef95d31e TM	27	* Convert the NFSv4 pathname components into a standard posix path.
	28	*
	29	* Note that the resulting string will be placed at the end of the buffer
f7b422b1	30	*/
509de811	31	static inline char nfs4_pathname_string(const struct nfs4_pathname pathname,
f7b422b1 DH	32	char *buffer, ssize_t buflen)
	33	{
	34	char *end = buffer + buflen;
	35	int n;
	36
	37	*--end = '\0';
	38	buflen--;
	39
	40	n = pathname->ncomponents;
	41	while (--n >= 0) {
509de811	42	const struct nfs4_string *component = &pathname->components[n];
f7b422b1 DH	43	buflen -= component->len + 1;
	44	if (buflen < 0)
	45	goto Elong;
	46	end -= component->len;
	47	memcpy(end, component->data, component->len);
	48	*--end = '/';
	49	}
	50	return end;
	51	Elong:
	52	return ERR_PTR(-ENAMETOOLONG);
	53	}
	54
1aba1567 WAA	55	/*
	56	* return the path component of "<server>:<path>"
	57	* nfspath - the "<server>:<path>" string
	58	* end - one past the last char that could contain "<server>:"
	59	* returns NULL on failure
	60	*/
	61	static char nfs_path_component(const char nfspath, const char *end)
	62	{
	63	char *p;
	64
	65	if (*nfspath == '[') {
	66	/* parse [] escaped IPv6 addrs */
	67	p = strchr(nfspath, ']');
	68	if (p != NULL && ++p < end && *p == ':')
	69	return p + 1;
	70	} else {
	71	/* otherwise split on first colon */
	72	p = strchr(nfspath, ':');
	73	if (p != NULL && p < end)
	74	return p + 1;
	75	}
	76	return NULL;
	77	}
	78
54ceac45 DH	79	/*
	80	* Determine the mount path as a string
	81	*/
b514f872	82	static char nfs4_path(struct dentry dentry, char *buffer, ssize_t buflen)
54ceac45	83	{
b514f872	84	char *limit;
97a54868 BH	85	char *path = nfs_path(&limit, dentry, buffer, buflen,
97a54868 BH	86	NFS_PATH_CANONICAL);
b514f872	87	if (!IS_ERR(path)) {
1aba1567 WAA	88	char *path_component = nfs_path_component(path, limit);
	89	if (path_component)
	90	return path_component;
b514f872 AV	91	}
b514f872 AV	92	return path;
54ceac45 DH	93	}
	94
	95	/*
	96	* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
	97	* believe to be the server path to this dentry
	98	*/
b514f872	99	static int nfs4_validate_fspath(struct dentry *dentry,
54ceac45 DH	100	const struct nfs4_fs_locations *locations,
	101	char page, char page2)
	102	{
	103	const char path, fs_path;
	104
b514f872	105	path = nfs4_path(dentry, page, PAGE_SIZE);
54ceac45 DH	106	if (IS_ERR(path))
	107	return PTR_ERR(path);
	108
	109	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	110	if (IS_ERR(fs_path))
	111	return PTR_ERR(fs_path);
	112
	113	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
	114	dprintk("%s: path %s does not begin with fsroot %s\n",
3110ff80	115	__func__, path, fs_path);
54ceac45 DH	116	return -ENOENT;
	117	}
	118
	119	return 0;
	120	}
	121
7d7ea882	122	static size_t nfs_parse_server_name(char *string, size_t len,
1b340d01	123	struct sockaddr sa, size_t salen, struct nfs_server server)
7d7ea882	124	{
2446ab60	125	struct net *net = rpc_net_ns(server->client);
7d7ea882 TM	126	ssize_t ret;
7d7ea882 TM	127
33faaa38	128	ret = rpc_pton(net, string, len, sa, salen);
7d7ea882	129	if (ret == 0) {
33faaa38	130	ret = nfs_dns_resolve_name(net, string, len, sa, salen);
7d7ea882 TM	131	if (ret < 0)
	132	ret = 0;
	133	}
	134	return ret;
	135	}
	136
9568c5e9 CL	137	/**
	138	* nfs_find_best_sec - Find a security mechanism supported locally
	139	* @flavors: List of security tuples returned by SECINFO procedure
	140	*
	141	* Return the pseudoflavor of the first security mechanism in
	142	* "flavors" that is locally supported. Return RPC_AUTH_UNIX if
	143	* no matching flavor is found in the array. The "flavors" array
	144	* is searched in the order returned from the server, per RFC 3530
	145	* recommendation.
	146	*/
2671bfc3 BS	147	rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
2671bfc3 BS	148	{
9568c5e9 CL	149	rpc_authflavor_t pseudoflavor;
9568c5e9 CL	150	struct nfs4_secinfo4 *secinfo;
fb15b26f	151	unsigned int i;
2671bfc3 BS	152
2671bfc3 BS	153	for (i = 0; i < flavors->num_flavors; i++) {
9568c5e9 CL	154	secinfo = &flavors->flavors[i];
	155
	156	switch (secinfo->flavor) {
	157	case RPC_AUTH_NULL:
	158	case RPC_AUTH_UNIX:
	159	case RPC_AUTH_GSS:
	160	pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
	161	&secinfo->flavor_info);
	162	if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
	163	return pseudoflavor;
2671bfc3 BS	164	break;
	165	}
	166	}
	167
9568c5e9	168	return RPC_AUTH_UNIX;
2671bfc3 BS	169	}
2671bfc3 BS	170
72de53ec BS	171	static rpc_authflavor_t nfs4_negotiate_security(struct inode inode, struct qstr name)
	172	{
	173	struct page *page;
	174	struct nfs4_secinfo_flavors *flavors;
	175	rpc_authflavor_t flavor;
	176	int err;
	177
	178	page = alloc_page(GFP_KERNEL);
	179	if (!page)
	180	return -ENOMEM;
	181	flavors = page_address(page);
	182
	183	err = nfs4_proc_secinfo(inode, name, flavors);
	184	if (err < 0) {
	185	flavor = err;
	186	goto out;
	187	}
	188
	189	flavor = nfs_find_best_sec(flavors);
	190
	191	out:
	192	put_page(page);
	193	return flavor;
	194	}
	195
	196	/*
	197	* Please call rpc_shutdown_client() when you are done with this client.
	198	*/
	199	struct rpc_clnt nfs4_create_sec_client(struct rpc_clnt clnt, struct inode *inode,
	200	struct qstr *name)
	201	{
72de53ec BS	202	rpc_authflavor_t flavor;
	203
	204	flavor = nfs4_negotiate_security(inode, name);
5f23eff3	205	if ((int)flavor < 0)
62d98c93	206	return ERR_PTR((int)flavor);
72de53ec	207
ba9b584c	208	return rpc_clone_client_set_auth(clnt, flavor);
72de53ec BS	209	}
72de53ec BS	210
4ada29d5 BF	211	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	212	char page, char page2,
	213	const struct nfs4_fs_location *location)
	214	{
364d015e	215	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
4ada29d5 BF	216	struct vfsmount *mnt = ERR_PTR(-ENOENT);
4ada29d5 BF	217	char *mnt_path;
ef95d31e	218	unsigned int maxbuflen;
460cdbc8	219	unsigned int s;
4ada29d5 BF	220
	221	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	222	if (IS_ERR(mnt_path))
517be09d	223	return ERR_CAST(mnt_path);
4ada29d5	224	mountdata->mnt_path = mnt_path;
ef95d31e	225	maxbuflen = mnt_path - 1 - page2;
4ada29d5	226
364d015e TM	227	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	228	if (mountdata->addr == NULL)
	229	return ERR_PTR(-ENOMEM);
	230
460cdbc8	231	for (s = 0; s < location->nservers; s++) {
ea31a443	232	const struct nfs4_string *buf = &location->servers[s];
4ada29d5	233
ef95d31e	234	if (buf->len <= 0 \|\| buf->len >= maxbuflen)
4ada29d5	235	continue;
4ada29d5	236
ea31a443 BF	237	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
ea31a443 BF	238	continue;
517be09d TM	239
517be09d TM	240	mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
1b340d01 SK	241	mountdata->addr, addr_bufsize,
1b340d01 SK	242	NFS_SB(mountdata->sb));
53a0b9c4	243	if (mountdata->addrlen == 0)
ea31a443	244	continue;
517be09d	245
ec6ee612	246	rpc_set_port(mountdata->addr, NFS_PORT);
ea31a443	247
ef95d31e TM	248	memcpy(page2, buf->data, buf->len);
ef95d31e TM	249	page2[buf->len] = '\0';
ea31a443	250	mountdata->hostname = page2;
4ada29d5 BF	251
	252	snprintf(page, PAGE_SIZE, "%s:%s",
	253	mountdata->hostname,
	254	mountdata->mnt_path);
	255
	256	mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
	257	if (!IS_ERR(mnt))
	258	break;
4ada29d5	259	}
364d015e	260	kfree(mountdata->addr);
4ada29d5 BF	261	return mnt;
	262	}
	263
f7b422b1 DH	264	/**
f7b422b1 DH	265	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
f7b422b1	266	* @dentry - parent directory
3f43c666	267	* @locations - array of NFSv4 server location information
f7b422b1 DH	268	*
f7b422b1 DH	269	*/
f8ad9c4b	270	static struct vfsmount nfs_follow_referral(struct dentry dentry,
509de811	271	const struct nfs4_fs_locations *locations)
f7b422b1 DH	272	{
	273	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	274	struct nfs_clone_mount mountdata = {
f8ad9c4b	275	.sb = dentry->d_sb,
f7b422b1	276	.dentry = dentry,
f8ad9c4b	277	.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
f7b422b1	278	};
54ceac45	279	char page = NULL, page2 = NULL;
3f43c666	280	int loc, error;
f7b422b1 DH	281
	282	if (locations == NULL \|\| locations->nlocations <= 0)
	283	goto out;
	284
3110ff80	285	dprintk("%s: referral at %s/%s\n", __func__,
f7b422b1 DH	286	dentry->d_parent->d_name.name, dentry->d_name.name);
f7b422b1 DH	287
f7b422b1	288	page = (char *) __get_free_page(GFP_USER);
54ceac45	289	if (!page)
f7b422b1	290	goto out;
54ceac45	291
f7b422b1	292	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	293	if (!page2)
f7b422b1 DH	294	goto out;
f7b422b1 DH	295
54ceac45	296	/* Ensure fs path is a prefix of current dentry path */
b514f872	297	error = nfs4_validate_fspath(dentry, locations, page, page2);
54ceac45 DH	298	if (error < 0) {
	299	mnt = ERR_PTR(error);
	300	goto out;
f7b422b1 DH	301	}
f7b422b1 DH	302
460cdbc8	303	for (loc = 0; loc < locations->nlocations; loc++) {
509de811	304	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	305
f7b422b1 DH	306	if (location == NULL \|\| location->nservers <= 0 \|\|
460cdbc8	307	location->rootpath.ncomponents == 0)
f7b422b1	308	continue;
f7b422b1	309
4ada29d5 BF	310	mnt = try_location(&mountdata, page, page2, location);
	311	if (!IS_ERR(mnt))
	312	break;
f7b422b1 DH	313	}
f7b422b1 DH	314
f7b422b1	315	out:
54ceac45 DH	316	free_page((unsigned long) page);
54ceac45 DH	317	free_page((unsigned long) page2);
3110ff80	318	dprintk("%s: done\n", __func__);
f7b422b1 DH	319	return mnt;
	320	}
	321
	322	/*
	323	* nfs_do_refmount - handle crossing a referral on server
	324	* @dentry - dentry of referral
f7b422b1 DH	325	*
f7b422b1 DH	326	*/
281cad46	327	static struct vfsmount nfs_do_refmount(struct rpc_clnt client, struct dentry *dentry)
f7b422b1	328	{
54ceac45	329	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	330	struct dentry *parent;
	331	struct nfs4_fs_locations *fs_locations = NULL;
	332	struct page *page;
	333	int err;
	334
	335	/* BUG_ON(IS_ROOT(dentry)); */
3110ff80	336	dprintk("%s: enter\n", __func__);
f7b422b1 DH	337
	338	page = alloc_page(GFP_KERNEL);
	339	if (page == NULL)
	340	goto out;
	341
	342	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	343	if (fs_locations == NULL)
	344	goto out_free;
	345
	346	/* Get locations */
54ceac45 DH	347	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	348
f7b422b1	349	parent = dget_parent(dentry);
54ceac45	350	dprintk("%s: getting locations for %s/%s\n",
3110ff80	351	__func__, parent->d_name.name, dentry->d_name.name);
54ceac45	352
f05d147f	353	err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
f7b422b1	354	dput(parent);
54ceac45 DH	355	if (err != 0 \|\|
54ceac45 DH	356	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	357	fs_locations->fs_path.ncomponents <= 0)
	358	goto out_free;
	359
f8ad9c4b	360	mnt = nfs_follow_referral(dentry, fs_locations);
f7b422b1 DH	361	out_free:
	362	__free_page(page);
	363	kfree(fs_locations);
	364	out:
3110ff80	365	dprintk("%s: done\n", __func__);
f7b422b1 DH	366	return mnt;
f7b422b1 DH	367	}
281cad46 BS	368
	369	struct vfsmount nfs4_submount(struct nfs_server server, struct dentry *dentry,
	370	struct nfs_fh fh, struct nfs_fattr fattr)
	371	{
	372	struct dentry *parent = dget_parent(dentry);
	373	struct rpc_clnt *client;
	374	struct vfsmount *mnt;
	375
	376	/* Look it up again to get its attributes and sec flavor */
	377	client = nfs4_proc_lookup_mountpoint(parent->d_inode, &dentry->d_name, fh, fattr);
	378	dput(parent);
	379	if (IS_ERR(client))
	380	return ERR_CAST(client);
	381
	382	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
	383	mnt = nfs_do_refmount(client, dentry);
	384	else
	385	mnt = nfs_do_submount(dentry, fh, fattr, client->cl_auth->au_flavor);
	386
	387	rpc_shutdown_client(client);
	388	return mnt;
	389	}