[mirror_ubuntu-bionic-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/nfs_mount.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
 * @server: NFS server struct
 * @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.
 */
static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
					  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);
			/* make sure pseudoflavor matches sec= mount opt */
			if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
			    nfs_auth_info_match(&server->auth_info,
						pseudoflavor))
				return pseudoflavor;
			break;
		}
	}

	/* if there were any sec= options then nothing matched */
	if (server->auth_info.flavor_len > 0)
		return -EPERM;

	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(NFS_SERVER(inode), 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 %pd2\n", __func__, dentry);

	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 %pd2\n",
		__func__, dentry);

	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)
{
	rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
	struct dentry *parent = dget_parent(dentry);
	struct inode *dir = parent->d_inode;
	struct qstr *name = &dentry->d_name;
	struct rpc_clnt *client;
	struct vfsmount *mnt;

	/* Look it up again to get its attributes and sec flavor */
	client = nfs4_proc_lookup_mountpoint(dir, 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);
		goto out;
	}

	if (client->cl_auth->au_flavor != flavor)
		flavor = client->cl_auth->au_flavor;
	else {
		rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
		if ((int)new >= 0)
			flavor = new;
	}
	mnt = nfs_do_submount(dentry, fh, fattr, flavor);
out:
	rpc_shutdown_client(client);
	return mnt;
}

/*
 * Try one location from the fs_locations array.
 *
 * Returns zero on success, or a negative errno value.
 */
static int nfs4_try_replacing_one_location(struct nfs_server *server,
		char *page, char *page2,
		const struct nfs4_fs_location *location)
{
	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
	struct sockaddr *sap;
	unsigned int s;
	size_t salen;
	int error;

	sap = kmalloc(addr_bufsize, GFP_KERNEL);
	if (sap == NULL)
		return -ENOMEM;

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

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

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

		salen = nfs_parse_server_name(buf->data, buf->len,
						sap, addr_bufsize, server);
		if (salen == 0)
			continue;
		rpc_set_port(sap, NFS_PORT);

		error = -ENOMEM;
		hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
		if (hostname == NULL)
			break;

		error = nfs4_update_server(server, hostname, sap, salen);
		kfree(hostname);
		if (error == 0)
			break;
	}

	kfree(sap);
	return error;
}

/**
 * nfs4_replace_transport - set up transport to destination server
 *
 * @server: export being migrated
 * @locations: fs_locations array
 *
 * Returns zero on success, or a negative errno value.
 *
 * The client tries all the entries in the "locations" array, in the
 * order returned by the server, until one works or the end of the
 * array is reached.
 */
int nfs4_replace_transport(struct nfs_server *server,
			   const struct nfs4_fs_locations *locations)
{
	char *page = NULL, *page2 = NULL;
	int loc, error;

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

	error = -ENOMEM;
	page = (char *) __get_free_page(GFP_USER);
	if (!page)
		goto out;
	page2 = (char *) __get_free_page(GFP_USER);
	if (!page2)
		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;

		error = nfs4_try_replacing_one_location(server, page,
							page2, location);
		if (error == 0)
			break;
	}

out:
	free_page((unsigned long)page);
	free_page((unsigned long)page2);
	return error;
}
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>
47040da3	14	#include <linux/nfs_mount.h>
5a0e3ad6	15	#include <linux/slab.h>
f7b422b1 DH	16	#include <linux/string.h>
f7b422b1 DH	17	#include <linux/sunrpc/clnt.h>
5976687a	18	#include <linux/sunrpc/addr.h>
f7b422b1 DH	19	#include <linux/vfs.h>
	20	#include <linux/inet.h>
	21	#include "internal.h"
c228fd3a	22	#include "nfs4_fs.h"
7d7ea882	23	#include "dns_resolve.h"
f7b422b1 DH	24
	25	#define NFSDBG_FACILITY NFSDBG_VFS
	26
	27	/*
ef95d31e TM	28	* Convert the NFSv4 pathname components into a standard posix path.
	29	*
	30	* Note that the resulting string will be placed at the end of the buffer
f7b422b1	31	*/
509de811	32	static inline char nfs4_pathname_string(const struct nfs4_pathname pathname,
f7b422b1 DH	33	char *buffer, ssize_t buflen)
	34	{
	35	char *end = buffer + buflen;
	36	int n;
	37
	38	*--end = '\0';
	39	buflen--;
	40
	41	n = pathname->ncomponents;
	42	while (--n >= 0) {
509de811	43	const struct nfs4_string *component = &pathname->components[n];
f7b422b1 DH	44	buflen -= component->len + 1;
	45	if (buflen < 0)
	46	goto Elong;
	47	end -= component->len;
	48	memcpy(end, component->data, component->len);
	49	*--end = '/';
	50	}
	51	return end;
	52	Elong:
	53	return ERR_PTR(-ENAMETOOLONG);
	54	}
	55
1aba1567 WAA	56	/*
	57	* return the path component of "<server>:<path>"
	58	* nfspath - the "<server>:<path>" string
	59	* end - one past the last char that could contain "<server>:"
	60	* returns NULL on failure
	61	*/
	62	static char nfs_path_component(const char nfspath, const char *end)
	63	{
	64	char *p;
	65
	66	if (*nfspath == '[') {
	67	/* parse [] escaped IPv6 addrs */
	68	p = strchr(nfspath, ']');
	69	if (p != NULL && ++p < end && *p == ':')
	70	return p + 1;
	71	} else {
	72	/* otherwise split on first colon */
	73	p = strchr(nfspath, ':');
	74	if (p != NULL && p < end)
	75	return p + 1;
	76	}
	77	return NULL;
	78	}
	79
54ceac45 DH	80	/*
	81	* Determine the mount path as a string
	82	*/
b514f872	83	static char nfs4_path(struct dentry dentry, char *buffer, ssize_t buflen)
54ceac45	84	{
b514f872	85	char *limit;
97a54868 BH	86	char *path = nfs_path(&limit, dentry, buffer, buflen,
97a54868 BH	87	NFS_PATH_CANONICAL);
b514f872	88	if (!IS_ERR(path)) {
1aba1567 WAA	89	char *path_component = nfs_path_component(path, limit);
	90	if (path_component)
	91	return path_component;
b514f872 AV	92	}
b514f872 AV	93	return path;
54ceac45 DH	94	}
	95
	96	/*
	97	* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
	98	* believe to be the server path to this dentry
	99	*/
b514f872	100	static int nfs4_validate_fspath(struct dentry *dentry,
54ceac45 DH	101	const struct nfs4_fs_locations *locations,
	102	char page, char page2)
	103	{
	104	const char path, fs_path;
	105
b514f872	106	path = nfs4_path(dentry, page, PAGE_SIZE);
54ceac45 DH	107	if (IS_ERR(path))
	108	return PTR_ERR(path);
	109
	110	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	111	if (IS_ERR(fs_path))
	112	return PTR_ERR(fs_path);
	113
	114	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
	115	dprintk("%s: path %s does not begin with fsroot %s\n",
3110ff80	116	__func__, path, fs_path);
54ceac45 DH	117	return -ENOENT;
	118	}
	119
	120	return 0;
	121	}
	122
7d7ea882	123	static size_t nfs_parse_server_name(char *string, size_t len,
1b340d01	124	struct sockaddr sa, size_t salen, struct nfs_server server)
7d7ea882	125	{
2446ab60	126	struct net *net = rpc_net_ns(server->client);
7d7ea882 TM	127	ssize_t ret;
7d7ea882 TM	128
33faaa38	129	ret = rpc_pton(net, string, len, sa, salen);
7d7ea882	130	if (ret == 0) {
33faaa38	131	ret = nfs_dns_resolve_name(net, string, len, sa, salen);
7d7ea882 TM	132	if (ret < 0)
	133	ret = 0;
	134	}
	135	return ret;
	136	}
	137
9568c5e9 CL	138	/**
9568c5e9 CL	139	* nfs_find_best_sec - Find a security mechanism supported locally
4d4b69dd	140	* @server: NFS server struct
9568c5e9 CL	141	* @flavors: List of security tuples returned by SECINFO procedure
	142	*
	143	* Return the pseudoflavor of the first security mechanism in
	144	* "flavors" that is locally supported. Return RPC_AUTH_UNIX if
	145	* no matching flavor is found in the array. The "flavors" array
	146	* is searched in the order returned from the server, per RFC 3530
	147	* recommendation.
	148	*/
4d4b69dd WAA	149	static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
4d4b69dd WAA	150	struct nfs4_secinfo_flavors *flavors)
2671bfc3	151	{
9568c5e9 CL	152	rpc_authflavor_t pseudoflavor;
9568c5e9 CL	153	struct nfs4_secinfo4 *secinfo;
fb15b26f	154	unsigned int i;
2671bfc3 BS	155
2671bfc3 BS	156	for (i = 0; i < flavors->num_flavors; i++) {
9568c5e9 CL	157	secinfo = &flavors->flavors[i];
	158
	159	switch (secinfo->flavor) {
	160	case RPC_AUTH_NULL:
	161	case RPC_AUTH_UNIX:
	162	case RPC_AUTH_GSS:
	163	pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
	164	&secinfo->flavor_info);
4d4b69dd WAA	165	/* make sure pseudoflavor matches sec= mount opt */
	166	if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
	167	nfs_auth_info_match(&server->auth_info,
	168	pseudoflavor))
9568c5e9	169	return pseudoflavor;
2671bfc3 BS	170	break;
	171	}
	172	}
	173
4d4b69dd WAA	174	/* if there were any sec= options then nothing matched */
	175	if (server->auth_info.flavor_len > 0)
	176	return -EPERM;
	177
9568c5e9	178	return RPC_AUTH_UNIX;
2671bfc3 BS	179	}
2671bfc3 BS	180
72de53ec BS	181	static rpc_authflavor_t nfs4_negotiate_security(struct inode inode, struct qstr name)
	182	{
	183	struct page *page;
	184	struct nfs4_secinfo_flavors *flavors;
	185	rpc_authflavor_t flavor;
	186	int err;
	187
	188	page = alloc_page(GFP_KERNEL);
	189	if (!page)
	190	return -ENOMEM;
	191	flavors = page_address(page);
	192
	193	err = nfs4_proc_secinfo(inode, name, flavors);
	194	if (err < 0) {
	195	flavor = err;
	196	goto out;
	197	}
	198
4d4b69dd	199	flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
72de53ec BS	200
	201	out:
	202	put_page(page);
	203	return flavor;
	204	}
	205
	206	/*
	207	* Please call rpc_shutdown_client() when you are done with this client.
	208	*/
	209	struct rpc_clnt nfs4_create_sec_client(struct rpc_clnt clnt, struct inode *inode,
	210	struct qstr *name)
	211	{
72de53ec BS	212	rpc_authflavor_t flavor;
	213
	214	flavor = nfs4_negotiate_security(inode, name);
5f23eff3	215	if ((int)flavor < 0)
62d98c93	216	return ERR_PTR((int)flavor);
72de53ec	217
ba9b584c	218	return rpc_clone_client_set_auth(clnt, flavor);
72de53ec BS	219	}
72de53ec BS	220
4ada29d5 BF	221	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	222	char page, char page2,
	223	const struct nfs4_fs_location *location)
	224	{
364d015e	225	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
4ada29d5 BF	226	struct vfsmount *mnt = ERR_PTR(-ENOENT);
4ada29d5 BF	227	char *mnt_path;
ef95d31e	228	unsigned int maxbuflen;
460cdbc8	229	unsigned int s;
4ada29d5 BF	230
	231	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	232	if (IS_ERR(mnt_path))
517be09d	233	return ERR_CAST(mnt_path);
4ada29d5	234	mountdata->mnt_path = mnt_path;
ef95d31e	235	maxbuflen = mnt_path - 1 - page2;
4ada29d5	236
364d015e TM	237	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	238	if (mountdata->addr == NULL)
	239	return ERR_PTR(-ENOMEM);
	240
460cdbc8	241	for (s = 0; s < location->nservers; s++) {
ea31a443	242	const struct nfs4_string *buf = &location->servers[s];
4ada29d5	243
ef95d31e	244	if (buf->len <= 0 \|\| buf->len >= maxbuflen)
4ada29d5	245	continue;
4ada29d5	246
ea31a443 BF	247	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
ea31a443 BF	248	continue;
517be09d TM	249
517be09d TM	250	mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
1b340d01 SK	251	mountdata->addr, addr_bufsize,
1b340d01 SK	252	NFS_SB(mountdata->sb));
53a0b9c4	253	if (mountdata->addrlen == 0)
ea31a443	254	continue;
517be09d	255
ec6ee612	256	rpc_set_port(mountdata->addr, NFS_PORT);
ea31a443	257
ef95d31e TM	258	memcpy(page2, buf->data, buf->len);
ef95d31e TM	259	page2[buf->len] = '\0';
ea31a443	260	mountdata->hostname = page2;
4ada29d5 BF	261
	262	snprintf(page, PAGE_SIZE, "%s:%s",
	263	mountdata->hostname,
	264	mountdata->mnt_path);
	265
	266	mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
	267	if (!IS_ERR(mnt))
	268	break;
4ada29d5	269	}
364d015e	270	kfree(mountdata->addr);
4ada29d5 BF	271	return mnt;
	272	}
	273
f7b422b1 DH	274	/**
f7b422b1 DH	275	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
f7b422b1	276	* @dentry - parent directory
3f43c666	277	* @locations - array of NFSv4 server location information
f7b422b1 DH	278	*
f7b422b1 DH	279	*/
f8ad9c4b	280	static struct vfsmount nfs_follow_referral(struct dentry dentry,
509de811	281	const struct nfs4_fs_locations *locations)
f7b422b1 DH	282	{
	283	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	284	struct nfs_clone_mount mountdata = {
f8ad9c4b	285	.sb = dentry->d_sb,
f7b422b1	286	.dentry = dentry,
f8ad9c4b	287	.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
f7b422b1	288	};
54ceac45	289	char page = NULL, page2 = NULL;
3f43c666	290	int loc, error;
f7b422b1 DH	291
	292	if (locations == NULL \|\| locations->nlocations <= 0)
	293	goto out;
	294
6de1472f	295	dprintk("%s: referral at %pd2\n", __func__, dentry);
f7b422b1	296
f7b422b1	297	page = (char *) __get_free_page(GFP_USER);
54ceac45	298	if (!page)
f7b422b1	299	goto out;
54ceac45	300
f7b422b1	301	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	302	if (!page2)
f7b422b1 DH	303	goto out;
f7b422b1 DH	304
54ceac45	305	/* Ensure fs path is a prefix of current dentry path */
b514f872	306	error = nfs4_validate_fspath(dentry, locations, page, page2);
54ceac45 DH	307	if (error < 0) {
	308	mnt = ERR_PTR(error);
	309	goto out;
f7b422b1 DH	310	}
f7b422b1 DH	311
460cdbc8	312	for (loc = 0; loc < locations->nlocations; loc++) {
509de811	313	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	314
f7b422b1 DH	315	if (location == NULL \|\| location->nservers <= 0 \|\|
460cdbc8	316	location->rootpath.ncomponents == 0)
f7b422b1	317	continue;
f7b422b1	318
4ada29d5 BF	319	mnt = try_location(&mountdata, page, page2, location);
	320	if (!IS_ERR(mnt))
	321	break;
f7b422b1 DH	322	}
f7b422b1 DH	323
f7b422b1	324	out:
54ceac45 DH	325	free_page((unsigned long) page);
54ceac45 DH	326	free_page((unsigned long) page2);
3110ff80	327	dprintk("%s: done\n", __func__);
f7b422b1 DH	328	return mnt;
	329	}
	330
	331	/*
	332	* nfs_do_refmount - handle crossing a referral on server
	333	* @dentry - dentry of referral
f7b422b1 DH	334	*
f7b422b1 DH	335	*/
281cad46	336	static struct vfsmount nfs_do_refmount(struct rpc_clnt client, struct dentry *dentry)
f7b422b1	337	{
54ceac45	338	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	339	struct dentry *parent;
	340	struct nfs4_fs_locations *fs_locations = NULL;
	341	struct page *page;
	342	int err;
	343
	344	/* BUG_ON(IS_ROOT(dentry)); */
3110ff80	345	dprintk("%s: enter\n", __func__);
f7b422b1 DH	346
	347	page = alloc_page(GFP_KERNEL);
	348	if (page == NULL)
	349	goto out;
	350
	351	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	352	if (fs_locations == NULL)
	353	goto out_free;
	354
	355	/* Get locations */
54ceac45 DH	356	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	357
f7b422b1	358	parent = dget_parent(dentry);
6de1472f AV	359	dprintk("%s: getting locations for %pd2\n",
6de1472f AV	360	__func__, dentry);
54ceac45	361
f05d147f	362	err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
f7b422b1	363	dput(parent);
54ceac45 DH	364	if (err != 0 \|\|
54ceac45 DH	365	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	366	fs_locations->fs_path.ncomponents <= 0)
	367	goto out_free;
	368
f8ad9c4b	369	mnt = nfs_follow_referral(dentry, fs_locations);
f7b422b1 DH	370	out_free:
	371	__free_page(page);
	372	kfree(fs_locations);
	373	out:
3110ff80	374	dprintk("%s: done\n", __func__);
f7b422b1 DH	375	return mnt;
f7b422b1 DH	376	}
281cad46 BS	377
	378	struct vfsmount nfs4_submount(struct nfs_server server, struct dentry *dentry,
	379	struct nfs_fh fh, struct nfs_fattr fattr)
	380	{
47040da3	381	rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
281cad46	382	struct dentry *parent = dget_parent(dentry);
47040da3 TM	383	struct inode *dir = parent->d_inode;
47040da3 TM	384	struct qstr *name = &dentry->d_name;
281cad46 BS	385	struct rpc_clnt *client;
	386	struct vfsmount *mnt;
	387
	388	/* Look it up again to get its attributes and sec flavor */
47040da3	389	client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
281cad46 BS	390	dput(parent);
	391	if (IS_ERR(client))
	392	return ERR_CAST(client);
	393
47040da3	394	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
281cad46	395	mnt = nfs_do_refmount(client, dentry);
47040da3 TM	396	goto out;
47040da3 TM	397	}
281cad46	398
47040da3 TM	399	if (client->cl_auth->au_flavor != flavor)
47040da3 TM	400	flavor = client->cl_auth->au_flavor;
4d4b69dd	401	else {
47040da3 TM	402	rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
	403	if ((int)new >= 0)
	404	flavor = new;
	405	}
	406	mnt = nfs_do_submount(dentry, fh, fattr, flavor);
	407	out:
281cad46 BS	408	rpc_shutdown_client(client);
	409	return mnt;
	410	}
800c06a5 CL	411
	412	/*
	413	* Try one location from the fs_locations array.
	414	*
	415	* Returns zero on success, or a negative errno value.
	416	*/
	417	static int nfs4_try_replacing_one_location(struct nfs_server *server,
	418	char page, char page2,
	419	const struct nfs4_fs_location *location)
	420	{
	421	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
	422	struct sockaddr *sap;
	423	unsigned int s;
	424	size_t salen;
	425	int error;
	426
	427	sap = kmalloc(addr_bufsize, GFP_KERNEL);
	428	if (sap == NULL)
	429	return -ENOMEM;
	430
	431	error = -ENOENT;
	432	for (s = 0; s < location->nservers; s++) {
	433	const struct nfs4_string *buf = &location->servers[s];
	434	char *hostname;
	435
	436	if (buf->len <= 0 \|\| buf->len > PAGE_SIZE)
	437	continue;
	438
	439	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
	440	continue;
	441
	442	salen = nfs_parse_server_name(buf->data, buf->len,
	443	sap, addr_bufsize, server);
	444	if (salen == 0)
	445	continue;
	446	rpc_set_port(sap, NFS_PORT);
	447
	448	error = -ENOMEM;
	449	hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
	450	if (hostname == NULL)
	451	break;
	452
	453	error = nfs4_update_server(server, hostname, sap, salen);
	454	kfree(hostname);
	455	if (error == 0)
	456	break;
	457	}
	458
	459	kfree(sap);
	460	return error;
	461	}
	462
	463	/**
	464	* nfs4_replace_transport - set up transport to destination server
	465	*
	466	* @server: export being migrated
	467	* @locations: fs_locations array
	468	*
	469	* Returns zero on success, or a negative errno value.
	470	*
	471	* The client tries all the entries in the "locations" array, in the
	472	* order returned by the server, until one works or the end of the
	473	* array is reached.
	474	*/
475	int nfs4_replace_transport(struct nfs_server *server,
476	const struct nfs4_fs_locations *locations)
477	{
478	char page = NULL, page2 = NULL;
479	int loc, error;
480
481	error = -ENOENT;
482	if (locations == NULL \|\| locations->nlocations <= 0)
483	goto out;
484
485	error = -ENOMEM;
486	page = (char *) __get_free_page(GFP_USER);
487	if (!page)
488	goto out;
489	page2 = (char *) __get_free_page(GFP_USER);
490	if (!page2)
491	goto out;
492
493	for (loc = 0; loc < locations->nlocations; loc++) {
494	const struct nfs4_fs_location *location =
495	&locations->locations[loc];
496
497	if (location == NULL \|\| location->nservers <= 0 \|\|
498	location->rootpath.ncomponents == 0)
499	continue;
500
501	error = nfs4_try_replacing_one_location(server, page,
502	page2, location);
503	if (error == 0)
504	break;
505	}
506
507	out:
508	free_page((unsigned long)page);
509	free_page((unsigned long)page2);
510	return error;
511	}