blob: ebd8b064843b4a506511c071f2bb7ec2dc638e76 [file] [log] [blame]
David Howellsf7b422b2006-06-09 09:34:33 -04001/*
2 * linux/fs/nfs/nfs4namespace.c
3 *
4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
David Howells54ceac42006-08-22 20:06:13 -04005 * - Modified by David Howells <dhowells@redhat.com>
David Howellsf7b422b2006-06-09 09:34:33 -04006 *
7 * NFSv4 namespace
8 */
9
David Howellsf7b422b2006-06-09 09:34:33 -040010#include <linux/dcache.h>
11#include <linux/mount.h>
12#include <linux/namei.h>
13#include <linux/nfs_fs.h>
Trond Myklebust47040da2013-09-07 16:01:07 -040014#include <linux/nfs_mount.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090015#include <linux/slab.h>
David Howellsf7b422b2006-06-09 09:34:33 -040016#include <linux/string.h>
17#include <linux/sunrpc/clnt.h>
Jeff Layton59766872013-02-04 12:50:00 -050018#include <linux/sunrpc/addr.h>
David Howellsf7b422b2006-06-09 09:34:33 -040019#include <linux/vfs.h>
20#include <linux/inet.h>
21#include "internal.h"
Trond Myklebustc228fd32007-01-13 02:28:11 -050022#include "nfs4_fs.h"
Trond Myklebust7d7ea882009-08-19 18:12:34 -040023#include "dns_resolve.h"
David Howellsf7b422b2006-06-09 09:34:33 -040024
25#define NFSDBG_FACILITY NFSDBG_VFS
26
27/*
Trond Myklebustef95d312009-03-10 20:33:17 -040028 * 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
David Howellsf7b422b2006-06-09 09:34:33 -040031 */
David Howells509de812006-08-22 20:06:11 -040032static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
David Howellsf7b422b2006-06-09 09:34:33 -040033 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) {
David Howells509de812006-08-22 20:06:11 -040043 const struct nfs4_string *component = &pathname->components[n];
David Howellsf7b422b2006-06-09 09:34:33 -040044 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;
52Elong:
53 return ERR_PTR(-ENAMETOOLONG);
54}
55
David Howells54ceac42006-08-22 20:06:13 -040056/*
Weston Andros Adamson1aba1562012-04-24 16:50:37 -040057 * 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 */
62static 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
80/*
David Howells54ceac42006-08-22 20:06:13 -040081 * Determine the mount path as a string
82 */
Al Virob514f872011-03-16 06:26:11 -040083static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
David Howells54ceac42006-08-22 20:06:13 -040084{
Al Virob514f872011-03-16 06:26:11 -040085 char *limit;
Ben Hutchings97a54862012-10-21 19:23:52 +010086 char *path = nfs_path(&limit, dentry, buffer, buflen,
87 NFS_PATH_CANONICAL);
Al Virob514f872011-03-16 06:26:11 -040088 if (!IS_ERR(path)) {
Weston Andros Adamson1aba1562012-04-24 16:50:37 -040089 char *path_component = nfs_path_component(path, limit);
90 if (path_component)
91 return path_component;
Al Virob514f872011-03-16 06:26:11 -040092 }
93 return path;
David Howells54ceac42006-08-22 20:06:13 -040094}
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 */
Al Virob514f872011-03-16 06:26:11 -0400100static int nfs4_validate_fspath(struct dentry *dentry,
David Howells54ceac42006-08-22 20:06:13 -0400101 const struct nfs4_fs_locations *locations,
102 char *page, char *page2)
103{
104 const char *path, *fs_path;
105
Al Virob514f872011-03-16 06:26:11 -0400106 path = nfs4_path(dentry, page, PAGE_SIZE);
David Howells54ceac42006-08-22 20:06:13 -0400107 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",
Harvey Harrison3110ff82008-05-02 13:42:44 -0700116 __func__, path, fs_path);
David Howells54ceac42006-08-22 20:06:13 -0400117 return -ENOENT;
118 }
119
120 return 0;
121}
122
Trond Myklebust7d7ea882009-08-19 18:12:34 -0400123static size_t nfs_parse_server_name(char *string, size_t len,
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300124 struct sockaddr *sa, size_t salen, struct nfs_server *server)
Trond Myklebust7d7ea882009-08-19 18:12:34 -0400125{
Trond Myklebust2446ab62012-03-01 17:00:56 -0500126 struct net *net = rpc_net_ns(server->client);
Trond Myklebust7d7ea882009-08-19 18:12:34 -0400127 ssize_t ret;
128
Stanislav Kinsbursky33faaa32012-01-26 15:12:05 +0400129 ret = rpc_pton(net, string, len, sa, salen);
Trond Myklebust7d7ea882009-08-19 18:12:34 -0400130 if (ret == 0) {
Stanislav Kinsbursky33faaa32012-01-26 15:12:05 +0400131 ret = nfs_dns_resolve_name(net, string, len, sa, salen);
Trond Myklebust7d7ea882009-08-19 18:12:34 -0400132 if (ret < 0)
133 ret = 0;
134 }
135 return ret;
136}
137
Chuck Lever9568c5e2013-03-16 15:54:43 -0400138/**
139 * nfs_find_best_sec - Find a security mechanism supported locally
140 * @flavors: List of security tuples returned by SECINFO procedure
141 *
142 * Return the pseudoflavor of the first security mechanism in
143 * "flavors" that is locally supported. Return RPC_AUTH_UNIX if
144 * no matching flavor is found in the array. The "flavors" array
145 * is searched in the order returned from the server, per RFC 3530
146 * recommendation.
147 */
Bryan Schumaker2671bfc2012-04-27 13:27:44 -0400148rpc_authflavor_t nfs_find_best_sec(struct nfs4_secinfo_flavors *flavors)
149{
Chuck Lever9568c5e2013-03-16 15:54:43 -0400150 rpc_authflavor_t pseudoflavor;
151 struct nfs4_secinfo4 *secinfo;
Chuck Leverfb15b262013-03-16 15:54:34 -0400152 unsigned int i;
Bryan Schumaker2671bfc2012-04-27 13:27:44 -0400153
154 for (i = 0; i < flavors->num_flavors; i++) {
Chuck Lever9568c5e2013-03-16 15:54:43 -0400155 secinfo = &flavors->flavors[i];
Bryan Schumaker2671bfc2012-04-27 13:27:44 -0400156
Chuck Lever9568c5e2013-03-16 15:54:43 -0400157 switch (secinfo->flavor) {
158 case RPC_AUTH_NULL:
159 case RPC_AUTH_UNIX:
160 case RPC_AUTH_GSS:
161 pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
162 &secinfo->flavor_info);
163 if (pseudoflavor != RPC_AUTH_MAXFLAVOR)
164 return pseudoflavor;
Bryan Schumaker2671bfc2012-04-27 13:27:44 -0400165 break;
166 }
167 }
168
Chuck Lever9568c5e2013-03-16 15:54:43 -0400169 return RPC_AUTH_UNIX;
Bryan Schumaker2671bfc2012-04-27 13:27:44 -0400170}
171
Bryan Schumaker72de53e2012-04-27 13:27:40 -0400172static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name)
173{
174 struct page *page;
175 struct nfs4_secinfo_flavors *flavors;
176 rpc_authflavor_t flavor;
177 int err;
178
179 page = alloc_page(GFP_KERNEL);
180 if (!page)
181 return -ENOMEM;
182 flavors = page_address(page);
183
184 err = nfs4_proc_secinfo(inode, name, flavors);
185 if (err < 0) {
186 flavor = err;
187 goto out;
188 }
189
190 flavor = nfs_find_best_sec(flavors);
191
192out:
193 put_page(page);
194 return flavor;
195}
196
197/*
198 * Please call rpc_shutdown_client() when you are done with this client.
199 */
200struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode,
201 struct qstr *name)
202{
Bryan Schumaker72de53e2012-04-27 13:27:40 -0400203 rpc_authflavor_t flavor;
204
205 flavor = nfs4_negotiate_security(inode, name);
Benny Halevy5f23eff32012-05-16 11:35:36 +0300206 if ((int)flavor < 0)
NeilBrown62d98c92012-09-17 16:46:34 +1000207 return ERR_PTR((int)flavor);
Bryan Schumaker72de53e2012-04-27 13:27:40 -0400208
Chuck Leverba9b5842012-09-14 17:24:02 -0400209 return rpc_clone_client_set_auth(clnt, flavor);
Bryan Schumaker72de53e2012-04-27 13:27:40 -0400210}
211
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400212static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
213 char *page, char *page2,
214 const struct nfs4_fs_location *location)
215{
Trond Myklebust364d015e52010-04-16 16:22:46 -0400216 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400217 struct vfsmount *mnt = ERR_PTR(-ENOENT);
218 char *mnt_path;
Trond Myklebustef95d312009-03-10 20:33:17 -0400219 unsigned int maxbuflen;
J. Bruce Fields460cdbc2008-08-20 16:10:21 -0400220 unsigned int s;
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400221
222 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
223 if (IS_ERR(mnt_path))
Trond Myklebust517be092009-10-06 15:42:20 -0400224 return ERR_CAST(mnt_path);
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400225 mountdata->mnt_path = mnt_path;
Trond Myklebustef95d312009-03-10 20:33:17 -0400226 maxbuflen = mnt_path - 1 - page2;
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400227
Trond Myklebust364d015e52010-04-16 16:22:46 -0400228 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
229 if (mountdata->addr == NULL)
230 return ERR_PTR(-ENOMEM);
231
J. Bruce Fields460cdbc2008-08-20 16:10:21 -0400232 for (s = 0; s < location->nservers; s++) {
J. Bruce Fieldsea31a4432008-08-20 16:10:23 -0400233 const struct nfs4_string *buf = &location->servers[s];
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400234
Trond Myklebustef95d312009-03-10 20:33:17 -0400235 if (buf->len <= 0 || buf->len >= maxbuflen)
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400236 continue;
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400237
J. Bruce Fieldsea31a4432008-08-20 16:10:23 -0400238 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
239 continue;
Trond Myklebust517be092009-10-06 15:42:20 -0400240
241 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
Stanislav Kinsbursky1b340d02011-11-25 17:13:04 +0300242 mountdata->addr, addr_bufsize,
243 NFS_SB(mountdata->sb));
Chuck Lever53a0b9c2009-08-09 15:09:36 -0400244 if (mountdata->addrlen == 0)
J. Bruce Fieldsea31a4432008-08-20 16:10:23 -0400245 continue;
Trond Myklebust517be092009-10-06 15:42:20 -0400246
Chuck Leverec6ee612009-08-09 15:09:37 -0400247 rpc_set_port(mountdata->addr, NFS_PORT);
J. Bruce Fieldsea31a4432008-08-20 16:10:23 -0400248
Trond Myklebustef95d312009-03-10 20:33:17 -0400249 memcpy(page2, buf->data, buf->len);
250 page2[buf->len] = '\0';
J. Bruce Fieldsea31a4432008-08-20 16:10:23 -0400251 mountdata->hostname = page2;
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400252
253 snprintf(page, PAGE_SIZE, "%s:%s",
254 mountdata->hostname,
255 mountdata->mnt_path);
256
257 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
258 if (!IS_ERR(mnt))
259 break;
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400260 }
Trond Myklebust364d015e52010-04-16 16:22:46 -0400261 kfree(mountdata->addr);
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400262 return mnt;
263}
264
David Howellsf7b422b2006-06-09 09:34:33 -0400265/**
266 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
David Howellsf7b422b2006-06-09 09:34:33 -0400267 * @dentry - parent directory
Chuck Lever3f43c662007-12-10 14:57:31 -0500268 * @locations - array of NFSv4 server location information
David Howellsf7b422b2006-06-09 09:34:33 -0400269 *
270 */
Al Virof8ad9c42011-03-16 06:32:07 -0400271static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
David Howells509de812006-08-22 20:06:11 -0400272 const struct nfs4_fs_locations *locations)
David Howellsf7b422b2006-06-09 09:34:33 -0400273{
274 struct vfsmount *mnt = ERR_PTR(-ENOENT);
275 struct nfs_clone_mount mountdata = {
Al Virof8ad9c42011-03-16 06:32:07 -0400276 .sb = dentry->d_sb,
David Howellsf7b422b2006-06-09 09:34:33 -0400277 .dentry = dentry,
Al Virof8ad9c42011-03-16 06:32:07 -0400278 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
David Howellsf7b422b2006-06-09 09:34:33 -0400279 };
David Howells54ceac42006-08-22 20:06:13 -0400280 char *page = NULL, *page2 = NULL;
Chuck Lever3f43c662007-12-10 14:57:31 -0500281 int loc, error;
David Howellsf7b422b2006-06-09 09:34:33 -0400282
283 if (locations == NULL || locations->nlocations <= 0)
284 goto out;
285
Harvey Harrison3110ff82008-05-02 13:42:44 -0700286 dprintk("%s: referral at %s/%s\n", __func__,
David Howellsf7b422b2006-06-09 09:34:33 -0400287 dentry->d_parent->d_name.name, dentry->d_name.name);
288
David Howellsf7b422b2006-06-09 09:34:33 -0400289 page = (char *) __get_free_page(GFP_USER);
David Howells54ceac42006-08-22 20:06:13 -0400290 if (!page)
David Howellsf7b422b2006-06-09 09:34:33 -0400291 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400292
David Howellsf7b422b2006-06-09 09:34:33 -0400293 page2 = (char *) __get_free_page(GFP_USER);
David Howells54ceac42006-08-22 20:06:13 -0400294 if (!page2)
David Howellsf7b422b2006-06-09 09:34:33 -0400295 goto out;
296
David Howells54ceac42006-08-22 20:06:13 -0400297 /* Ensure fs path is a prefix of current dentry path */
Al Virob514f872011-03-16 06:26:11 -0400298 error = nfs4_validate_fspath(dentry, locations, page, page2);
David Howells54ceac42006-08-22 20:06:13 -0400299 if (error < 0) {
300 mnt = ERR_PTR(error);
301 goto out;
David Howellsf7b422b2006-06-09 09:34:33 -0400302 }
303
J. Bruce Fields460cdbc2008-08-20 16:10:21 -0400304 for (loc = 0; loc < locations->nlocations; loc++) {
David Howells509de812006-08-22 20:06:11 -0400305 const struct nfs4_fs_location *location = &locations->locations[loc];
David Howellsf7b422b2006-06-09 09:34:33 -0400306
307 if (location == NULL || location->nservers <= 0 ||
J. Bruce Fields460cdbc2008-08-20 16:10:21 -0400308 location->rootpath.ncomponents == 0)
David Howellsf7b422b2006-06-09 09:34:33 -0400309 continue;
David Howellsf7b422b2006-06-09 09:34:33 -0400310
J. Bruce Fields4ada29d2008-08-20 16:10:20 -0400311 mnt = try_location(&mountdata, page, page2, location);
312 if (!IS_ERR(mnt))
313 break;
David Howellsf7b422b2006-06-09 09:34:33 -0400314 }
315
David Howellsf7b422b2006-06-09 09:34:33 -0400316out:
David Howells54ceac42006-08-22 20:06:13 -0400317 free_page((unsigned long) page);
318 free_page((unsigned long) page2);
Harvey Harrison3110ff82008-05-02 13:42:44 -0700319 dprintk("%s: done\n", __func__);
David Howellsf7b422b2006-06-09 09:34:33 -0400320 return mnt;
321}
322
323/*
324 * nfs_do_refmount - handle crossing a referral on server
325 * @dentry - dentry of referral
David Howellsf7b422b2006-06-09 09:34:33 -0400326 *
327 */
Bryan Schumaker281cad42012-04-27 13:27:45 -0400328static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
David Howellsf7b422b2006-06-09 09:34:33 -0400329{
David Howells54ceac42006-08-22 20:06:13 -0400330 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
David Howellsf7b422b2006-06-09 09:34:33 -0400331 struct dentry *parent;
332 struct nfs4_fs_locations *fs_locations = NULL;
333 struct page *page;
334 int err;
335
336 /* BUG_ON(IS_ROOT(dentry)); */
Harvey Harrison3110ff82008-05-02 13:42:44 -0700337 dprintk("%s: enter\n", __func__);
David Howellsf7b422b2006-06-09 09:34:33 -0400338
339 page = alloc_page(GFP_KERNEL);
340 if (page == NULL)
341 goto out;
342
343 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
344 if (fs_locations == NULL)
345 goto out_free;
346
347 /* Get locations */
David Howells54ceac42006-08-22 20:06:13 -0400348 mnt = ERR_PTR(-ENOENT);
349
David Howellsf7b422b2006-06-09 09:34:33 -0400350 parent = dget_parent(dentry);
David Howells54ceac42006-08-22 20:06:13 -0400351 dprintk("%s: getting locations for %s/%s\n",
Harvey Harrison3110ff82008-05-02 13:42:44 -0700352 __func__, parent->d_name.name, dentry->d_name.name);
David Howells54ceac42006-08-22 20:06:13 -0400353
Bryan Schumakerf05d1472012-04-27 13:27:41 -0400354 err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
David Howellsf7b422b2006-06-09 09:34:33 -0400355 dput(parent);
David Howells54ceac42006-08-22 20:06:13 -0400356 if (err != 0 ||
357 fs_locations->nlocations <= 0 ||
David Howellsf7b422b2006-06-09 09:34:33 -0400358 fs_locations->fs_path.ncomponents <= 0)
359 goto out_free;
360
Al Virof8ad9c42011-03-16 06:32:07 -0400361 mnt = nfs_follow_referral(dentry, fs_locations);
David Howellsf7b422b2006-06-09 09:34:33 -0400362out_free:
363 __free_page(page);
364 kfree(fs_locations);
365out:
Harvey Harrison3110ff82008-05-02 13:42:44 -0700366 dprintk("%s: done\n", __func__);
David Howellsf7b422b2006-06-09 09:34:33 -0400367 return mnt;
368}
Bryan Schumaker281cad42012-04-27 13:27:45 -0400369
370struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
371 struct nfs_fh *fh, struct nfs_fattr *fattr)
372{
Trond Myklebust47040da2013-09-07 16:01:07 -0400373 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
Bryan Schumaker281cad42012-04-27 13:27:45 -0400374 struct dentry *parent = dget_parent(dentry);
Trond Myklebust47040da2013-09-07 16:01:07 -0400375 struct inode *dir = parent->d_inode;
376 struct qstr *name = &dentry->d_name;
Bryan Schumaker281cad42012-04-27 13:27:45 -0400377 struct rpc_clnt *client;
378 struct vfsmount *mnt;
379
380 /* Look it up again to get its attributes and sec flavor */
Trond Myklebust47040da2013-09-07 16:01:07 -0400381 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
Bryan Schumaker281cad42012-04-27 13:27:45 -0400382 dput(parent);
383 if (IS_ERR(client))
384 return ERR_CAST(client);
385
Trond Myklebust47040da2013-09-07 16:01:07 -0400386 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
Bryan Schumaker281cad42012-04-27 13:27:45 -0400387 mnt = nfs_do_refmount(client, dentry);
Trond Myklebust47040da2013-09-07 16:01:07 -0400388 goto out;
389 }
Bryan Schumaker281cad42012-04-27 13:27:45 -0400390
Trond Myklebust47040da2013-09-07 16:01:07 -0400391 if (client->cl_auth->au_flavor != flavor)
392 flavor = client->cl_auth->au_flavor;
393 else if (!(server->flags & NFS_MOUNT_SECFLAVOUR)) {
394 rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
395 if ((int)new >= 0)
396 flavor = new;
397 }
398 mnt = nfs_do_submount(dentry, fh, fattr, flavor);
399out:
Bryan Schumaker281cad42012-04-27 13:27:45 -0400400 rpc_shutdown_client(client);
401 return mnt;
402}
Chuck Lever800c06a2013-10-17 14:12:34 -0400403
404/*
405 * Try one location from the fs_locations array.
406 *
407 * Returns zero on success, or a negative errno value.
408 */
409static int nfs4_try_replacing_one_location(struct nfs_server *server,
410 char *page, char *page2,
411 const struct nfs4_fs_location *location)
412{
413 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
414 struct sockaddr *sap;
415 unsigned int s;
416 size_t salen;
417 int error;
418
419 sap = kmalloc(addr_bufsize, GFP_KERNEL);
420 if (sap == NULL)
421 return -ENOMEM;
422
423 error = -ENOENT;
424 for (s = 0; s < location->nservers; s++) {
425 const struct nfs4_string *buf = &location->servers[s];
426 char *hostname;
427
428 if (buf->len <= 0 || buf->len > PAGE_SIZE)
429 continue;
430
431 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
432 continue;
433
434 salen = nfs_parse_server_name(buf->data, buf->len,
435 sap, addr_bufsize, server);
436 if (salen == 0)
437 continue;
438 rpc_set_port(sap, NFS_PORT);
439
440 error = -ENOMEM;
441 hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
442 if (hostname == NULL)
443 break;
444
445 error = nfs4_update_server(server, hostname, sap, salen);
446 kfree(hostname);
447 if (error == 0)
448 break;
449 }
450
451 kfree(sap);
452 return error;
453}
454
455/**
456 * nfs4_replace_transport - set up transport to destination server
457 *
458 * @server: export being migrated
459 * @locations: fs_locations array
460 *
461 * Returns zero on success, or a negative errno value.
462 *
463 * The client tries all the entries in the "locations" array, in the
464 * order returned by the server, until one works or the end of the
465 * array is reached.
466 */
467int nfs4_replace_transport(struct nfs_server *server,
468 const struct nfs4_fs_locations *locations)
469{
470 char *page = NULL, *page2 = NULL;
471 int loc, error;
472
473 error = -ENOENT;
474 if (locations == NULL || locations->nlocations <= 0)
475 goto out;
476
477 error = -ENOMEM;
478 page = (char *) __get_free_page(GFP_USER);
479 if (!page)
480 goto out;
481 page2 = (char *) __get_free_page(GFP_USER);
482 if (!page2)
483 goto out;
484
485 for (loc = 0; loc < locations->nlocations; loc++) {
486 const struct nfs4_fs_location *location =
487 &locations->locations[loc];
488
489 if (location == NULL || location->nservers <= 0 ||
490 location->rootpath.ncomponents == 0)
491 continue;
492
493 error = nfs4_try_replacing_one_location(server, page,
494 page2, location);
495 if (error == 0)
496 break;
497 }
498
499out:
500 free_page((unsigned long)page);
501 free_page((unsigned long)page2);
502 return error;
503}