[linux.git] / fs / nfs / nfs4namespace.c

/*
 * linux/fs/nfs/nfs4namespace.c
 *
 * Copyright (C) 2005 Trond Myklebust <[email protected]>
 * - Modified by David Howells <[email protected]>
 *
 * 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 net *net)
{
	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 an rpc client that uses the first security mechanism in
 * "flavors" that is locally supported.  The "flavors" array
 * is searched in the order returned from the server, per RFC 3530
 * recommendation and each flavor is checked for membership in the
 * sec= mount option list if it exists.
 *
 * Return -EPERM if no matching flavor is found in the array.
 *
 * Please call rpc_shutdown_client() when you are done with this rpc client.
 *
 */
static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
					  struct nfs_server *server,
					  struct nfs4_secinfo_flavors *flavors)
{
	rpc_authflavor_t pflavor;
	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:
			pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
							&secinfo->flavor_info);
			/* does the pseudoflavor match a sec= mount opt? */
			if (pflavor != RPC_AUTH_MAXFLAVOR &&
			    nfs_auth_info_match(&server->auth_info, pflavor)) {
				struct rpc_clnt *new;
				struct rpc_cred *cred;

				/* Cloning creates an rpc_auth for the flavor */
				new = rpc_clone_client_set_auth(clnt, pflavor);
				if (IS_ERR(new))
					continue;
				/**
				* Check that the user actually can use the
				* flavor. This is mostly for RPC_AUTH_GSS
				* where cr_init obtains a gss context
				*/
				cred = rpcauth_lookupcred(new->cl_auth, 0);
				if (IS_ERR(cred)) {
					rpc_shutdown_client(new);
					continue;
				}
				put_rpccred(cred);
				return new;
			}
		}
	}
	return ERR_PTR(-EPERM);
}

/**
 * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
 * return an rpc_clnt that uses the best available security flavor with
 * respect to the secinfo flavor list and the sec= mount options.
 *
 * @clnt: RPC client to clone
 * @inode: directory inode
 * @name: lookup name
 *
 * Please call rpc_shutdown_client() when you are done with this rpc client.
 */
struct rpc_clnt *
nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
					const struct qstr *name)
{
	struct page *page;
	struct nfs4_secinfo_flavors *flavors;
	struct rpc_clnt *new;
	int err;

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

	flavors = page_address(page);

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

	new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);

out:
	put_page(page);
	return new;
}

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 net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
	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, net);
		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_submount(mountdata->dentry, &nfs4_referral_fs_type, 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);
	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)); */
	page = alloc_page(GFP_KERNEL);
	if (page == NULL)
		return mnt;

	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, d_inode(parent), &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);
	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 = d_inode(parent);
	const 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;
	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 net *net = rpc_net_ns(server->client);
	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, net);
		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, net);
		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 <[email protected]>
54ceac45	5	* - Modified by David Howells <[email protected]>
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,
292f503c	124	struct sockaddr sa, size_t salen, struct net net)
7d7ea882 TM	125	{
	126	ssize_t ret;
	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	/**
9568c5e9 CL	138	* nfs_find_best_sec - Find a security mechanism supported locally
4d4b69dd	139	* @server: NFS server struct
9568c5e9 CL	140	* @flavors: List of security tuples returned by SECINFO procedure
9568c5e9 CL	141	*
66b06860 AA	142	* Return an rpc client that uses the first security mechanism in
66b06860 AA	143	* "flavors" that is locally supported. The "flavors" array
9568c5e9	144	* is searched in the order returned from the server, per RFC 3530
66b06860 AA	145	* recommendation and each flavor is checked for membership in the
66b06860 AA	146	* sec= mount option list if it exists.
8445cd35 AA	147	*
8445cd35 AA	148	* Return -EPERM if no matching flavor is found in the array.
66b06860 AA	149	*
	150	* Please call rpc_shutdown_client() when you are done with this rpc client.
	151	*
9568c5e9	152	*/
66b06860 AA	153	static struct rpc_clnt nfs_find_best_sec(struct rpc_clnt clnt,
66b06860 AA	154	struct nfs_server *server,
4d4b69dd	155	struct nfs4_secinfo_flavors *flavors)
2671bfc3	156	{
66b06860	157	rpc_authflavor_t pflavor;
9568c5e9	158	struct nfs4_secinfo4 *secinfo;
fb15b26f	159	unsigned int i;
2671bfc3 BS	160
2671bfc3 BS	161	for (i = 0; i < flavors->num_flavors; i++) {
9568c5e9 CL	162	secinfo = &flavors->flavors[i];
	163
	164	switch (secinfo->flavor) {
	165	case RPC_AUTH_NULL:
	166	case RPC_AUTH_UNIX:
	167	case RPC_AUTH_GSS:
66b06860	168	pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
9568c5e9	169	&secinfo->flavor_info);
66b06860 AA	170	/* does the pseudoflavor match a sec= mount opt? */
	171	if (pflavor != RPC_AUTH_MAXFLAVOR &&
	172	nfs_auth_info_match(&server->auth_info, pflavor)) {
	173	struct rpc_clnt *new;
	174	struct rpc_cred *cred;
	175
	176	/* Cloning creates an rpc_auth for the flavor */
	177	new = rpc_clone_client_set_auth(clnt, pflavor);
	178	if (IS_ERR(new))
	179	continue;
	180	/**
	181	* Check that the user actually can use the
	182	* flavor. This is mostly for RPC_AUTH_GSS
	183	* where cr_init obtains a gss context
	184	*/
	185	cred = rpcauth_lookupcred(new->cl_auth, 0);
	186	if (IS_ERR(cred)) {
	187	rpc_shutdown_client(new);
	188	continue;
	189	}
	190	put_rpccred(cred);
	191	return new;
	192	}
2671bfc3 BS	193	}
2671bfc3 BS	194	}
66b06860	195	return ERR_PTR(-EPERM);
2671bfc3 BS	196	}
2671bfc3 BS	197
66b06860 AA	198	/**
	199	* nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
	200	* return an rpc_clnt that uses the best available security flavor with
	201	* respect to the secinfo flavor list and the sec= mount options.
	202	*
	203	* @clnt: RPC client to clone
	204	* @inode: directory inode
	205	* @name: lookup name
	206	*
	207	* Please call rpc_shutdown_client() when you are done with this rpc client.
	208	*/
	209	struct rpc_clnt *
	210	nfs4_negotiate_security(struct rpc_clnt clnt, struct inode inode,
beffb8fe	211	const struct qstr *name)
72de53ec BS	212	{
	213	struct page *page;
	214	struct nfs4_secinfo_flavors *flavors;
66b06860	215	struct rpc_clnt *new;
72de53ec BS	216	int err;
	217
	218	page = alloc_page(GFP_KERNEL);
	219	if (!page)
66b06860 AA	220	return ERR_PTR(-ENOMEM);
66b06860 AA	221
72de53ec BS	222	flavors = page_address(page);
	223
	224	err = nfs4_proc_secinfo(inode, name, flavors);
	225	if (err < 0) {
66b06860	226	new = ERR_PTR(err);
72de53ec BS	227	goto out;
	228	}
	229
66b06860	230	new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
72de53ec BS	231
	232	out:
	233	put_page(page);
66b06860	234	return new;
72de53ec BS	235	}
72de53ec BS	236
4ada29d5 BF	237	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	238	char page, char page2,
	239	const struct nfs4_fs_location *location)
	240	{
364d015e	241	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
292f503c	242	struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
4ada29d5 BF	243	struct vfsmount *mnt = ERR_PTR(-ENOENT);
4ada29d5 BF	244	char *mnt_path;
ef95d31e	245	unsigned int maxbuflen;
460cdbc8	246	unsigned int s;
4ada29d5 BF	247
	248	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	249	if (IS_ERR(mnt_path))
517be09d	250	return ERR_CAST(mnt_path);
4ada29d5	251	mountdata->mnt_path = mnt_path;
ef95d31e	252	maxbuflen = mnt_path - 1 - page2;
4ada29d5	253
364d015e TM	254	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	255	if (mountdata->addr == NULL)
	256	return ERR_PTR(-ENOMEM);
	257
460cdbc8	258	for (s = 0; s < location->nservers; s++) {
ea31a443	259	const struct nfs4_string *buf = &location->servers[s];
4ada29d5	260
ef95d31e	261	if (buf->len <= 0 \|\| buf->len >= maxbuflen)
4ada29d5	262	continue;
4ada29d5	263
ea31a443 BF	264	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
ea31a443 BF	265	continue;
517be09d TM	266
517be09d TM	267	mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
292f503c	268	mountdata->addr, addr_bufsize, net);
53a0b9c4	269	if (mountdata->addrlen == 0)
ea31a443	270	continue;
517be09d	271
ec6ee612	272	rpc_set_port(mountdata->addr, NFS_PORT);
ea31a443	273
ef95d31e TM	274	memcpy(page2, buf->data, buf->len);
ef95d31e TM	275	page2[buf->len] = '\0';
ea31a443	276	mountdata->hostname = page2;
4ada29d5 BF	277
	278	snprintf(page, PAGE_SIZE, "%s:%s",
	279	mountdata->hostname,
	280	mountdata->mnt_path);
	281
93faccbb	282	mnt = vfs_submount(mountdata->dentry, &nfs4_referral_fs_type, page, mountdata);
4ada29d5 BF	283	if (!IS_ERR(mnt))
4ada29d5 BF	284	break;
4ada29d5	285	}
364d015e	286	kfree(mountdata->addr);
4ada29d5 BF	287	return mnt;
	288	}
	289
f7b422b1 DH	290	/**
f7b422b1 DH	291	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
f7b422b1	292	* @dentry - parent directory
3f43c666	293	* @locations - array of NFSv4 server location information
f7b422b1 DH	294	*
f7b422b1 DH	295	*/
f8ad9c4b	296	static struct vfsmount nfs_follow_referral(struct dentry dentry,
509de811	297	const struct nfs4_fs_locations *locations)
f7b422b1 DH	298	{
	299	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	300	struct nfs_clone_mount mountdata = {
f8ad9c4b	301	.sb = dentry->d_sb,
f7b422b1	302	.dentry = dentry,
f8ad9c4b	303	.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
f7b422b1	304	};
54ceac45	305	char page = NULL, page2 = NULL;
3f43c666	306	int loc, error;
f7b422b1 DH	307
	308	if (locations == NULL \|\| locations->nlocations <= 0)
	309	goto out;
	310
6de1472f	311	dprintk("%s: referral at %pd2\n", __func__, dentry);
f7b422b1	312
f7b422b1	313	page = (char *) __get_free_page(GFP_USER);
54ceac45	314	if (!page)
f7b422b1	315	goto out;
54ceac45	316
f7b422b1	317	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	318	if (!page2)
f7b422b1 DH	319	goto out;
f7b422b1 DH	320
54ceac45	321	/* Ensure fs path is a prefix of current dentry path */
b514f872	322	error = nfs4_validate_fspath(dentry, locations, page, page2);
54ceac45 DH	323	if (error < 0) {
	324	mnt = ERR_PTR(error);
	325	goto out;
f7b422b1 DH	326	}
f7b422b1 DH	327
460cdbc8	328	for (loc = 0; loc < locations->nlocations; loc++) {
509de811	329	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	330
f7b422b1 DH	331	if (location == NULL \|\| location->nservers <= 0 \|\|
460cdbc8	332	location->rootpath.ncomponents == 0)
f7b422b1	333	continue;
f7b422b1	334
4ada29d5 BF	335	mnt = try_location(&mountdata, page, page2, location);
	336	if (!IS_ERR(mnt))
	337	break;
f7b422b1 DH	338	}
f7b422b1 DH	339
f7b422b1	340	out:
54ceac45 DH	341	free_page((unsigned long) page);
54ceac45 DH	342	free_page((unsigned long) page2);
f7b422b1 DH	343	return mnt;
	344	}
	345
	346	/*
	347	* nfs_do_refmount - handle crossing a referral on server
	348	* @dentry - dentry of referral
f7b422b1 DH	349	*
f7b422b1 DH	350	*/
281cad46	351	static struct vfsmount nfs_do_refmount(struct rpc_clnt client, struct dentry *dentry)
f7b422b1	352	{
54ceac45	353	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	354	struct dentry *parent;
	355	struct nfs4_fs_locations *fs_locations = NULL;
	356	struct page *page;
	357	int err;
	358
	359	/* BUG_ON(IS_ROOT(dentry)); */
f7b422b1 DH	360	page = alloc_page(GFP_KERNEL);
f7b422b1 DH	361	if (page == NULL)
3183783b	362	return mnt;
f7b422b1 DH	363
	364	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	365	if (fs_locations == NULL)
	366	goto out_free;
	367
	368	/* Get locations */
54ceac45 DH	369	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	370
f7b422b1	371	parent = dget_parent(dentry);
6de1472f AV	372	dprintk("%s: getting locations for %pd2\n",
6de1472f AV	373	__func__, dentry);
54ceac45	374
2b0143b5	375	err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
f7b422b1	376	dput(parent);
54ceac45 DH	377	if (err != 0 \|\|
54ceac45 DH	378	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	379	fs_locations->fs_path.ncomponents <= 0)
	380	goto out_free;
	381
f8ad9c4b	382	mnt = nfs_follow_referral(dentry, fs_locations);
f7b422b1 DH	383	out_free:
	384	__free_page(page);
	385	kfree(fs_locations);
f7b422b1 DH	386	return mnt;
f7b422b1 DH	387	}
281cad46 BS	388
	389	struct vfsmount nfs4_submount(struct nfs_server server, struct dentry *dentry,
	390	struct nfs_fh fh, struct nfs_fattr fattr)
	391	{
47040da3	392	rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
281cad46	393	struct dentry *parent = dget_parent(dentry);
2b0143b5	394	struct inode *dir = d_inode(parent);
beffb8fe	395	const struct qstr *name = &dentry->d_name;
281cad46 BS	396	struct rpc_clnt *client;
	397	struct vfsmount *mnt;
	398
	399	/* Look it up again to get its attributes and sec flavor */
47040da3	400	client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
281cad46 BS	401	dput(parent);
	402	if (IS_ERR(client))
	403	return ERR_CAST(client);
	404
47040da3	405	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
281cad46	406	mnt = nfs_do_refmount(client, dentry);
47040da3 TM	407	goto out;
47040da3 TM	408	}
281cad46	409
47040da3 TM	410	if (client->cl_auth->au_flavor != flavor)
47040da3 TM	411	flavor = client->cl_auth->au_flavor;
47040da3 TM	412	mnt = nfs_do_submount(dentry, fh, fattr, flavor);
47040da3 TM	413	out:
281cad46 BS	414	rpc_shutdown_client(client);
	415	return mnt;
	416	}
800c06a5 CL	417
	418	/*
	419	* Try one location from the fs_locations array.
	420	*
	421	* Returns zero on success, or a negative errno value.
	422	*/
	423	static int nfs4_try_replacing_one_location(struct nfs_server *server,
	424	char page, char page2,
	425	const struct nfs4_fs_location *location)
	426	{
	427	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
292f503c	428	struct net *net = rpc_net_ns(server->client);
800c06a5 CL	429	struct sockaddr *sap;
	430	unsigned int s;
	431	size_t salen;
	432	int error;
	433
	434	sap = kmalloc(addr_bufsize, GFP_KERNEL);
	435	if (sap == NULL)
	436	return -ENOMEM;
	437
	438	error = -ENOENT;
	439	for (s = 0; s < location->nservers; s++) {
	440	const struct nfs4_string *buf = &location->servers[s];
	441	char *hostname;
	442
	443	if (buf->len <= 0 \|\| buf->len > PAGE_SIZE)
	444	continue;
	445
	446	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
	447	continue;
	448
	449	salen = nfs_parse_server_name(buf->data, buf->len,
292f503c	450	sap, addr_bufsize, net);
800c06a5 CL	451	if (salen == 0)
	452	continue;
	453	rpc_set_port(sap, NFS_PORT);
	454
	455	error = -ENOMEM;
	456	hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
	457	if (hostname == NULL)
	458	break;
	459
292f503c	460	error = nfs4_update_server(server, hostname, sap, salen, net);
800c06a5 CL	461	kfree(hostname);
	462	if (error == 0)
	463	break;
	464	}
	465
	466	kfree(sap);
	467	return error;
	468	}
	469
	470	/**
	471	* nfs4_replace_transport - set up transport to destination server
	472	*
	473	* @server: export being migrated
	474	* @locations: fs_locations array
	475	*
	476	* Returns zero on success, or a negative errno value.
	477	*
	478	* The client tries all the entries in the "locations" array, in the
	479	* order returned by the server, until one works or the end of the
	480	* array is reached.
	481	*/
	482	int nfs4_replace_transport(struct nfs_server *server,
	483	const struct nfs4_fs_locations *locations)
	484	{
	485	char page = NULL, page2 = NULL;
	486	int loc, error;
	487
	488	error = -ENOENT;
	489	if (locations == NULL \|\| locations->nlocations <= 0)
	490	goto out;
	491
	492	error = -ENOMEM;
	493	page = (char *) __get_free_page(GFP_USER);
	494	if (!page)
	495	goto out;
	496	page2 = (char *) __get_free_page(GFP_USER);
	497	if (!page2)
	498	goto out;
	499
	500	for (loc = 0; loc < locations->nlocations; loc++) {
	501	const struct nfs4_fs_location *location =
	502	&locations->locations[loc];
	503
	504	if (location == NULL \|\| location->nservers <= 0 \|\|
	505	location->rootpath.ncomponents == 0)
	506	continue;
	507
	508	error = nfs4_try_replacing_one_location(server, page,
	509	page2, location);
	510	if (error == 0)
	511	break;
	512	}
	513
	514	out:
	515	free_page((unsigned long)page);
	516	free_page((unsigned long)page2);
	517	return error;
	518	}