[mirror_ubuntu-artful-kernel.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;
}

rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
{
	struct gss_api_mech *mech;
	struct xdr_netobj oid;
	int i;
	rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX;

	for (i = 0; i < flavors->num_flavors; i++) {
		struct nfs4_secinfo_flavor *flavor;
		flavor = &flavors->flavors[i];

		if (flavor->flavor == RPC_AUTH_NULL || flavor->flavor == RPC_AUTH_UNIX) {
			pseudoflavor = flavor->flavor;
			break;
		} else if (flavor->flavor == RPC_AUTH_GSS) {
			oid.len  = flavor->gss.sec_oid4.len;
			oid.data = flavor->gss.sec_oid4.data;
			mech = gss_mech_get_by_OID(&oid);
			if (!mech)
				continue;
			pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service);
			gss_mech_put(mech);
			break;
		}
	}

	return pseudoflavor;
}

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
2671bfc3 BS	137	rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
	138	{
	139	struct gss_api_mech *mech;
	140	struct xdr_netobj oid;
	141	int i;
	142	rpc_authflavor_t pseudoflavor = RPC_AUTH_UNIX;
	143
	144	for (i = 0; i < flavors->num_flavors; i++) {
	145	struct nfs4_secinfo_flavor *flavor;
	146	flavor = &flavors->flavors[i];
	147
	148	if (flavor->flavor == RPC_AUTH_NULL \|\| flavor->flavor == RPC_AUTH_UNIX) {
	149	pseudoflavor = flavor->flavor;
	150	break;
	151	} else if (flavor->flavor == RPC_AUTH_GSS) {
	152	oid.len = flavor->gss.sec_oid4.len;
	153	oid.data = flavor->gss.sec_oid4.data;
	154	mech = gss_mech_get_by_OID(&oid);
	155	if (!mech)
	156	continue;
	157	pseudoflavor = gss_svc_to_pseudoflavor(mech, flavor->gss.service);
	158	gss_mech_put(mech);
	159	break;
	160	}
	161	}
	162
	163	return pseudoflavor;
	164	}
	165
72de53ec BS	166	static rpc_authflavor_t nfs4_negotiate_security(struct inode inode, struct qstr name)
	167	{
	168	struct page *page;
	169	struct nfs4_secinfo_flavors *flavors;
	170	rpc_authflavor_t flavor;
	171	int err;
	172
	173	page = alloc_page(GFP_KERNEL);
	174	if (!page)
	175	return -ENOMEM;
	176	flavors = page_address(page);
	177
	178	err = nfs4_proc_secinfo(inode, name, flavors);
	179	if (err < 0) {
	180	flavor = err;
	181	goto out;
	182	}
	183
	184	flavor = nfs_find_best_sec(flavors);
	185
	186	out:
	187	put_page(page);
	188	return flavor;
	189	}
	190
	191	/*
	192	* Please call rpc_shutdown_client() when you are done with this client.
	193	*/
	194	struct rpc_clnt nfs4_create_sec_client(struct rpc_clnt clnt, struct inode *inode,
	195	struct qstr *name)
	196	{
72de53ec BS	197	rpc_authflavor_t flavor;
	198
	199	flavor = nfs4_negotiate_security(inode, name);
5f23eff3	200	if ((int)flavor < 0)
62d98c93	201	return ERR_PTR((int)flavor);
72de53ec	202
ba9b584c	203	return rpc_clone_client_set_auth(clnt, flavor);
72de53ec BS	204	}
72de53ec BS	205
4ada29d5 BF	206	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	207	char page, char page2,
	208	const struct nfs4_fs_location *location)
	209	{
364d015e	210	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
4ada29d5 BF	211	struct vfsmount *mnt = ERR_PTR(-ENOENT);
4ada29d5 BF	212	char *mnt_path;
ef95d31e	213	unsigned int maxbuflen;
460cdbc8	214	unsigned int s;
4ada29d5 BF	215
	216	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	217	if (IS_ERR(mnt_path))
517be09d	218	return ERR_CAST(mnt_path);
4ada29d5	219	mountdata->mnt_path = mnt_path;
ef95d31e	220	maxbuflen = mnt_path - 1 - page2;
4ada29d5	221
364d015e TM	222	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	223	if (mountdata->addr == NULL)
	224	return ERR_PTR(-ENOMEM);
	225
460cdbc8	226	for (s = 0; s < location->nservers; s++) {
ea31a443	227	const struct nfs4_string *buf = &location->servers[s];
4ada29d5	228
ef95d31e	229	if (buf->len <= 0 \|\| buf->len >= maxbuflen)
4ada29d5	230	continue;
4ada29d5	231
ea31a443 BF	232	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
ea31a443 BF	233	continue;
517be09d TM	234
517be09d TM	235	mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
1b340d01 SK	236	mountdata->addr, addr_bufsize,
1b340d01 SK	237	NFS_SB(mountdata->sb));
53a0b9c4	238	if (mountdata->addrlen == 0)
ea31a443	239	continue;
517be09d	240
ec6ee612	241	rpc_set_port(mountdata->addr, NFS_PORT);
ea31a443	242
ef95d31e TM	243	memcpy(page2, buf->data, buf->len);
ef95d31e TM	244	page2[buf->len] = '\0';
ea31a443	245	mountdata->hostname = page2;
4ada29d5 BF	246
	247	snprintf(page, PAGE_SIZE, "%s:%s",
	248	mountdata->hostname,
	249	mountdata->mnt_path);
	250
	251	mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
	252	if (!IS_ERR(mnt))
	253	break;
4ada29d5	254	}
364d015e	255	kfree(mountdata->addr);
4ada29d5 BF	256	return mnt;
	257	}
	258
f7b422b1 DH	259	/**
f7b422b1 DH	260	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
f7b422b1	261	* @dentry - parent directory
3f43c666	262	* @locations - array of NFSv4 server location information
f7b422b1 DH	263	*
f7b422b1 DH	264	*/
f8ad9c4b	265	static struct vfsmount nfs_follow_referral(struct dentry dentry,
509de811	266	const struct nfs4_fs_locations *locations)
f7b422b1 DH	267	{
	268	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	269	struct nfs_clone_mount mountdata = {
f8ad9c4b	270	.sb = dentry->d_sb,
f7b422b1	271	.dentry = dentry,
f8ad9c4b	272	.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
f7b422b1	273	};
54ceac45	274	char page = NULL, page2 = NULL;
3f43c666	275	int loc, error;
f7b422b1 DH	276
	277	if (locations == NULL \|\| locations->nlocations <= 0)
	278	goto out;
	279
3110ff80	280	dprintk("%s: referral at %s/%s\n", __func__,
f7b422b1 DH	281	dentry->d_parent->d_name.name, dentry->d_name.name);
f7b422b1 DH	282
f7b422b1	283	page = (char *) __get_free_page(GFP_USER);
54ceac45	284	if (!page)
f7b422b1	285	goto out;
54ceac45	286
f7b422b1	287	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	288	if (!page2)
f7b422b1 DH	289	goto out;
f7b422b1 DH	290
54ceac45	291	/* Ensure fs path is a prefix of current dentry path */
b514f872	292	error = nfs4_validate_fspath(dentry, locations, page, page2);
54ceac45 DH	293	if (error < 0) {
	294	mnt = ERR_PTR(error);
	295	goto out;
f7b422b1 DH	296	}
f7b422b1 DH	297
460cdbc8	298	for (loc = 0; loc < locations->nlocations; loc++) {
509de811	299	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	300
f7b422b1 DH	301	if (location == NULL \|\| location->nservers <= 0 \|\|
460cdbc8	302	location->rootpath.ncomponents == 0)
f7b422b1	303	continue;
f7b422b1	304
4ada29d5 BF	305	mnt = try_location(&mountdata, page, page2, location);
	306	if (!IS_ERR(mnt))
	307	break;
f7b422b1 DH	308	}
f7b422b1 DH	309
f7b422b1	310	out:
54ceac45 DH	311	free_page((unsigned long) page);
54ceac45 DH	312	free_page((unsigned long) page2);
3110ff80	313	dprintk("%s: done\n", __func__);
f7b422b1 DH	314	return mnt;
	315	}
	316
	317	/*
	318	* nfs_do_refmount - handle crossing a referral on server
	319	* @dentry - dentry of referral
f7b422b1 DH	320	*
f7b422b1 DH	321	*/
281cad46	322	static struct vfsmount nfs_do_refmount(struct rpc_clnt client, struct dentry *dentry)
f7b422b1	323	{
54ceac45	324	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	325	struct dentry *parent;
	326	struct nfs4_fs_locations *fs_locations = NULL;
	327	struct page *page;
	328	int err;
	329
	330	/* BUG_ON(IS_ROOT(dentry)); */
3110ff80	331	dprintk("%s: enter\n", __func__);
f7b422b1 DH	332
	333	page = alloc_page(GFP_KERNEL);
	334	if (page == NULL)
	335	goto out;
	336
	337	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	338	if (fs_locations == NULL)
	339	goto out_free;
	340
	341	/* Get locations */
54ceac45 DH	342	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	343
f7b422b1	344	parent = dget_parent(dentry);
54ceac45	345	dprintk("%s: getting locations for %s/%s\n",
3110ff80	346	__func__, parent->d_name.name, dentry->d_name.name);
54ceac45	347
f05d147f	348	err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
f7b422b1	349	dput(parent);
54ceac45 DH	350	if (err != 0 \|\|
54ceac45 DH	351	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	352	fs_locations->fs_path.ncomponents <= 0)
	353	goto out_free;
	354
f8ad9c4b	355	mnt = nfs_follow_referral(dentry, fs_locations);
f7b422b1 DH	356	out_free:
	357	__free_page(page);
	358	kfree(fs_locations);
	359	out:
3110ff80	360	dprintk("%s: done\n", __func__);
f7b422b1 DH	361	return mnt;
f7b422b1 DH	362	}
281cad46 BS	363
	364	struct vfsmount nfs4_submount(struct nfs_server server, struct dentry *dentry,
	365	struct nfs_fh fh, struct nfs_fattr fattr)
	366	{
	367	struct dentry *parent = dget_parent(dentry);
	368	struct rpc_clnt *client;
	369	struct vfsmount *mnt;
	370
	371	/* Look it up again to get its attributes and sec flavor */
	372	client = nfs4_proc_lookup_mountpoint(parent->d_inode, &dentry->d_name, fh, fattr);
	373	dput(parent);
	374	if (IS_ERR(client))
	375	return ERR_CAST(client);
	376
	377	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
	378	mnt = nfs_do_refmount(client, dentry);
	379	else
	380	mnt = nfs_do_submount(dentry, fh, fattr, client->cl_auth->au_flavor);
	381
	382	rpc_shutdown_client(client);
	383	return mnt;
	384	}