Loading...
1/*
2 * linux/fs/nfs/nfs4namespace.c
3 *
4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
5 * - Modified by David Howells <dhowells@redhat.com>
6 *
7 * NFSv4 namespace
8 */
9
10#include <linux/dcache.h>
11#include <linux/mount.h>
12#include <linux/namei.h>
13#include <linux/nfs_fs.h>
14#include <linux/slab.h>
15#include <linux/string.h>
16#include <linux/sunrpc/clnt.h>
17#include <linux/vfs.h>
18#include <linux/inet.h>
19#include "internal.h"
20#include "nfs4_fs.h"
21#include "dns_resolve.h"
22
23#define NFSDBG_FACILITY NFSDBG_VFS
24
25/*
26 * Convert the NFSv4 pathname components into a standard posix path.
27 *
28 * Note that the resulting string will be placed at the end of the buffer
29 */
30static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
31 char *buffer, ssize_t buflen)
32{
33 char *end = buffer + buflen;
34 int n;
35
36 *--end = '\0';
37 buflen--;
38
39 n = pathname->ncomponents;
40 while (--n >= 0) {
41 const struct nfs4_string *component = &pathname->components[n];
42 buflen -= component->len + 1;
43 if (buflen < 0)
44 goto Elong;
45 end -= component->len;
46 memcpy(end, component->data, component->len);
47 *--end = '/';
48 }
49 return end;
50Elong:
51 return ERR_PTR(-ENAMETOOLONG);
52}
53
54/*
55 * Determine the mount path as a string
56 */
57static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
58{
59 char *limit;
60 char *path = nfs_path(&limit, dentry, buffer, buflen);
61 if (!IS_ERR(path)) {
62 char *colon = strchr(path, ':');
63 if (colon && colon < limit)
64 path = colon + 1;
65 }
66 return path;
67}
68
69/*
70 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
71 * believe to be the server path to this dentry
72 */
73static int nfs4_validate_fspath(struct dentry *dentry,
74 const struct nfs4_fs_locations *locations,
75 char *page, char *page2)
76{
77 const char *path, *fs_path;
78
79 path = nfs4_path(dentry, page, PAGE_SIZE);
80 if (IS_ERR(path))
81 return PTR_ERR(path);
82
83 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
84 if (IS_ERR(fs_path))
85 return PTR_ERR(fs_path);
86
87 if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
88 dprintk("%s: path %s does not begin with fsroot %s\n",
89 __func__, path, fs_path);
90 return -ENOENT;
91 }
92
93 return 0;
94}
95
96static size_t nfs_parse_server_name(char *string, size_t len,
97 struct sockaddr *sa, size_t salen)
98{
99 ssize_t ret;
100
101 ret = rpc_pton(string, len, sa, salen);
102 if (ret == 0) {
103 ret = nfs_dns_resolve_name(string, len, sa, salen);
104 if (ret < 0)
105 ret = 0;
106 }
107 return ret;
108}
109
110static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
111 char *page, char *page2,
112 const struct nfs4_fs_location *location)
113{
114 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
115 struct vfsmount *mnt = ERR_PTR(-ENOENT);
116 char *mnt_path;
117 unsigned int maxbuflen;
118 unsigned int s;
119
120 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
121 if (IS_ERR(mnt_path))
122 return ERR_CAST(mnt_path);
123 mountdata->mnt_path = mnt_path;
124 maxbuflen = mnt_path - 1 - page2;
125
126 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
127 if (mountdata->addr == NULL)
128 return ERR_PTR(-ENOMEM);
129
130 for (s = 0; s < location->nservers; s++) {
131 const struct nfs4_string *buf = &location->servers[s];
132
133 if (buf->len <= 0 || buf->len >= maxbuflen)
134 continue;
135
136 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
137 continue;
138
139 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
140 mountdata->addr, addr_bufsize);
141 if (mountdata->addrlen == 0)
142 continue;
143
144 rpc_set_port(mountdata->addr, NFS_PORT);
145
146 memcpy(page2, buf->data, buf->len);
147 page2[buf->len] = '\0';
148 mountdata->hostname = page2;
149
150 snprintf(page, PAGE_SIZE, "%s:%s",
151 mountdata->hostname,
152 mountdata->mnt_path);
153
154 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
155 if (!IS_ERR(mnt))
156 break;
157 }
158 kfree(mountdata->addr);
159 return mnt;
160}
161
162/**
163 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
164 * @dentry - parent directory
165 * @locations - array of NFSv4 server location information
166 *
167 */
168static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
169 const struct nfs4_fs_locations *locations)
170{
171 struct vfsmount *mnt = ERR_PTR(-ENOENT);
172 struct nfs_clone_mount mountdata = {
173 .sb = dentry->d_sb,
174 .dentry = dentry,
175 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
176 };
177 char *page = NULL, *page2 = NULL;
178 int loc, error;
179
180 if (locations == NULL || locations->nlocations <= 0)
181 goto out;
182
183 dprintk("%s: referral at %s/%s\n", __func__,
184 dentry->d_parent->d_name.name, dentry->d_name.name);
185
186 page = (char *) __get_free_page(GFP_USER);
187 if (!page)
188 goto out;
189
190 page2 = (char *) __get_free_page(GFP_USER);
191 if (!page2)
192 goto out;
193
194 /* Ensure fs path is a prefix of current dentry path */
195 error = nfs4_validate_fspath(dentry, locations, page, page2);
196 if (error < 0) {
197 mnt = ERR_PTR(error);
198 goto out;
199 }
200
201 for (loc = 0; loc < locations->nlocations; loc++) {
202 const struct nfs4_fs_location *location = &locations->locations[loc];
203
204 if (location == NULL || location->nservers <= 0 ||
205 location->rootpath.ncomponents == 0)
206 continue;
207
208 mnt = try_location(&mountdata, page, page2, location);
209 if (!IS_ERR(mnt))
210 break;
211 }
212
213out:
214 free_page((unsigned long) page);
215 free_page((unsigned long) page2);
216 dprintk("%s: done\n", __func__);
217 return mnt;
218}
219
220/*
221 * nfs_do_refmount - handle crossing a referral on server
222 * @dentry - dentry of referral
223 *
224 */
225struct vfsmount *nfs_do_refmount(struct dentry *dentry)
226{
227 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
228 struct dentry *parent;
229 struct nfs4_fs_locations *fs_locations = NULL;
230 struct page *page;
231 int err;
232
233 /* BUG_ON(IS_ROOT(dentry)); */
234 dprintk("%s: enter\n", __func__);
235
236 page = alloc_page(GFP_KERNEL);
237 if (page == NULL)
238 goto out;
239
240 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
241 if (fs_locations == NULL)
242 goto out_free;
243
244 /* Get locations */
245 mnt = ERR_PTR(-ENOENT);
246
247 parent = dget_parent(dentry);
248 dprintk("%s: getting locations for %s/%s\n",
249 __func__, parent->d_name.name, dentry->d_name.name);
250
251 err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
252 dput(parent);
253 if (err != 0 ||
254 fs_locations->nlocations <= 0 ||
255 fs_locations->fs_path.ncomponents <= 0)
256 goto out_free;
257
258 mnt = nfs_follow_referral(dentry, fs_locations);
259out_free:
260 __free_page(page);
261 kfree(fs_locations);
262out:
263 dprintk("%s: done\n", __func__);
264 return mnt;
265}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/nfs/nfs4namespace.c
4 *
5 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
6 * - Modified by David Howells <dhowells@redhat.com>
7 *
8 * NFSv4 namespace
9 */
10
11#include <linux/dcache.h>
12#include <linux/mount.h>
13#include <linux/namei.h>
14#include <linux/nfs_fs.h>
15#include <linux/nfs_mount.h>
16#include <linux/slab.h>
17#include <linux/string.h>
18#include <linux/sunrpc/clnt.h>
19#include <linux/sunrpc/addr.h>
20#include <linux/vfs.h>
21#include <linux/inet.h>
22#include "internal.h"
23#include "nfs4_fs.h"
24#include "dns_resolve.h"
25
26#define NFSDBG_FACILITY NFSDBG_VFS
27
28/*
29 * Convert the NFSv4 pathname components into a standard posix path.
30 *
31 * Note that the resulting string will be placed at the end of the buffer
32 */
33static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
34 char *buffer, ssize_t buflen)
35{
36 char *end = buffer + buflen;
37 int n;
38
39 *--end = '\0';
40 buflen--;
41
42 n = pathname->ncomponents;
43 while (--n >= 0) {
44 const struct nfs4_string *component = &pathname->components[n];
45 buflen -= component->len + 1;
46 if (buflen < 0)
47 goto Elong;
48 end -= component->len;
49 memcpy(end, component->data, component->len);
50 *--end = '/';
51 }
52 return end;
53Elong:
54 return ERR_PTR(-ENAMETOOLONG);
55}
56
57/*
58 * return the path component of "<server>:<path>"
59 * nfspath - the "<server>:<path>" string
60 * end - one past the last char that could contain "<server>:"
61 * returns NULL on failure
62 */
63static char *nfs_path_component(const char *nfspath, const char *end)
64{
65 char *p;
66
67 if (*nfspath == '[') {
68 /* parse [] escaped IPv6 addrs */
69 p = strchr(nfspath, ']');
70 if (p != NULL && ++p < end && *p == ':')
71 return p + 1;
72 } else {
73 /* otherwise split on first colon */
74 p = strchr(nfspath, ':');
75 if (p != NULL && p < end)
76 return p + 1;
77 }
78 return NULL;
79}
80
81/*
82 * Determine the mount path as a string
83 */
84static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
85{
86 char *limit;
87 char *path = nfs_path(&limit, dentry, buffer, buflen,
88 NFS_PATH_CANONICAL);
89 if (!IS_ERR(path)) {
90 char *path_component = nfs_path_component(path, limit);
91 if (path_component)
92 return path_component;
93 }
94 return path;
95}
96
97/*
98 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
99 * believe to be the server path to this dentry
100 */
101static int nfs4_validate_fspath(struct dentry *dentry,
102 const struct nfs4_fs_locations *locations,
103 char *page, char *page2)
104{
105 const char *path, *fs_path;
106
107 path = nfs4_path(dentry, page, PAGE_SIZE);
108 if (IS_ERR(path))
109 return PTR_ERR(path);
110
111 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
112 if (IS_ERR(fs_path))
113 return PTR_ERR(fs_path);
114
115 if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
116 dprintk("%s: path %s does not begin with fsroot %s\n",
117 __func__, path, fs_path);
118 return -ENOENT;
119 }
120
121 return 0;
122}
123
124static size_t nfs_parse_server_name(char *string, size_t len,
125 struct sockaddr *sa, size_t salen, struct net *net)
126{
127 ssize_t ret;
128
129 ret = rpc_pton(net, string, len, sa, salen);
130 if (ret == 0) {
131 ret = nfs_dns_resolve_name(net, string, len, sa, salen);
132 if (ret < 0)
133 ret = 0;
134 }
135 return ret;
136}
137
138/**
139 * nfs_find_best_sec - Find a security mechanism supported locally
140 * @server: NFS server struct
141 * @flavors: List of security tuples returned by SECINFO procedure
142 *
143 * Return an rpc client that uses the first security mechanism in
144 * "flavors" that is locally supported. The "flavors" array
145 * is searched in the order returned from the server, per RFC 3530
146 * recommendation and each flavor is checked for membership in the
147 * sec= mount option list if it exists.
148 *
149 * Return -EPERM if no matching flavor is found in the array.
150 *
151 * Please call rpc_shutdown_client() when you are done with this rpc client.
152 *
153 */
154static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
155 struct nfs_server *server,
156 struct nfs4_secinfo_flavors *flavors)
157{
158 rpc_authflavor_t pflavor;
159 struct nfs4_secinfo4 *secinfo;
160 unsigned int i;
161
162 for (i = 0; i < flavors->num_flavors; i++) {
163 secinfo = &flavors->flavors[i];
164
165 switch (secinfo->flavor) {
166 case RPC_AUTH_NULL:
167 case RPC_AUTH_UNIX:
168 case RPC_AUTH_GSS:
169 pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
170 &secinfo->flavor_info);
171 /* does the pseudoflavor match a sec= mount opt? */
172 if (pflavor != RPC_AUTH_MAXFLAVOR &&
173 nfs_auth_info_match(&server->auth_info, pflavor)) {
174 struct rpc_clnt *new;
175 struct rpc_cred *cred;
176
177 /* Cloning creates an rpc_auth for the flavor */
178 new = rpc_clone_client_set_auth(clnt, pflavor);
179 if (IS_ERR(new))
180 continue;
181 /**
182 * Check that the user actually can use the
183 * flavor. This is mostly for RPC_AUTH_GSS
184 * where cr_init obtains a gss context
185 */
186 cred = rpcauth_lookupcred(new->cl_auth, 0);
187 if (IS_ERR(cred)) {
188 rpc_shutdown_client(new);
189 continue;
190 }
191 put_rpccred(cred);
192 return new;
193 }
194 }
195 }
196 return ERR_PTR(-EPERM);
197}
198
199/**
200 * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
201 * return an rpc_clnt that uses the best available security flavor with
202 * respect to the secinfo flavor list and the sec= mount options.
203 *
204 * @clnt: RPC client to clone
205 * @inode: directory inode
206 * @name: lookup name
207 *
208 * Please call rpc_shutdown_client() when you are done with this rpc client.
209 */
210struct rpc_clnt *
211nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
212 const struct qstr *name)
213{
214 struct page *page;
215 struct nfs4_secinfo_flavors *flavors;
216 struct rpc_clnt *new;
217 int err;
218
219 page = alloc_page(GFP_KERNEL);
220 if (!page)
221 return ERR_PTR(-ENOMEM);
222
223 flavors = page_address(page);
224
225 err = nfs4_proc_secinfo(inode, name, flavors);
226 if (err < 0) {
227 new = ERR_PTR(err);
228 goto out;
229 }
230
231 new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
232
233out:
234 put_page(page);
235 return new;
236}
237
238static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
239 char *page, char *page2,
240 const struct nfs4_fs_location *location)
241{
242 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
243 struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
244 struct vfsmount *mnt = ERR_PTR(-ENOENT);
245 char *mnt_path;
246 unsigned int maxbuflen;
247 unsigned int s;
248
249 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
250 if (IS_ERR(mnt_path))
251 return ERR_CAST(mnt_path);
252 mountdata->mnt_path = mnt_path;
253 maxbuflen = mnt_path - 1 - page2;
254
255 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
256 if (mountdata->addr == NULL)
257 return ERR_PTR(-ENOMEM);
258
259 for (s = 0; s < location->nservers; s++) {
260 const struct nfs4_string *buf = &location->servers[s];
261
262 if (buf->len <= 0 || buf->len >= maxbuflen)
263 continue;
264
265 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
266 continue;
267
268 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
269 mountdata->addr, addr_bufsize, net);
270 if (mountdata->addrlen == 0)
271 continue;
272
273 memcpy(page2, buf->data, buf->len);
274 page2[buf->len] = '\0';
275 mountdata->hostname = page2;
276
277 snprintf(page, PAGE_SIZE, "%s:%s",
278 mountdata->hostname,
279 mountdata->mnt_path);
280
281 mnt = vfs_submount(mountdata->dentry, &nfs4_referral_fs_type, page, mountdata);
282 if (!IS_ERR(mnt))
283 break;
284 }
285 kfree(mountdata->addr);
286 return mnt;
287}
288
289/**
290 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
291 * @dentry - parent directory
292 * @locations - array of NFSv4 server location information
293 *
294 */
295static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
296 const struct nfs4_fs_locations *locations)
297{
298 struct vfsmount *mnt = ERR_PTR(-ENOENT);
299 struct nfs_clone_mount mountdata = {
300 .sb = dentry->d_sb,
301 .dentry = dentry,
302 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
303 };
304 char *page = NULL, *page2 = NULL;
305 int loc, error;
306
307 if (locations == NULL || locations->nlocations <= 0)
308 goto out;
309
310 dprintk("%s: referral at %pd2\n", __func__, dentry);
311
312 page = (char *) __get_free_page(GFP_USER);
313 if (!page)
314 goto out;
315
316 page2 = (char *) __get_free_page(GFP_USER);
317 if (!page2)
318 goto out;
319
320 /* Ensure fs path is a prefix of current dentry path */
321 error = nfs4_validate_fspath(dentry, locations, page, page2);
322 if (error < 0) {
323 mnt = ERR_PTR(error);
324 goto out;
325 }
326
327 for (loc = 0; loc < locations->nlocations; loc++) {
328 const struct nfs4_fs_location *location = &locations->locations[loc];
329
330 if (location == NULL || location->nservers <= 0 ||
331 location->rootpath.ncomponents == 0)
332 continue;
333
334 mnt = try_location(&mountdata, page, page2, location);
335 if (!IS_ERR(mnt))
336 break;
337 }
338
339out:
340 free_page((unsigned long) page);
341 free_page((unsigned long) page2);
342 return mnt;
343}
344
345/*
346 * nfs_do_refmount - handle crossing a referral on server
347 * @dentry - dentry of referral
348 *
349 */
350static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
351{
352 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
353 struct dentry *parent;
354 struct nfs4_fs_locations *fs_locations = NULL;
355 struct page *page;
356 int err;
357
358 /* BUG_ON(IS_ROOT(dentry)); */
359 page = alloc_page(GFP_KERNEL);
360 if (page == NULL)
361 return mnt;
362
363 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
364 if (fs_locations == NULL)
365 goto out_free;
366
367 /* Get locations */
368 mnt = ERR_PTR(-ENOENT);
369
370 parent = dget_parent(dentry);
371 dprintk("%s: getting locations for %pd2\n",
372 __func__, dentry);
373
374 err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
375 dput(parent);
376 if (err != 0 ||
377 fs_locations->nlocations <= 0 ||
378 fs_locations->fs_path.ncomponents <= 0)
379 goto out_free;
380
381 mnt = nfs_follow_referral(dentry, fs_locations);
382out_free:
383 __free_page(page);
384 kfree(fs_locations);
385 return mnt;
386}
387
388struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
389 struct nfs_fh *fh, struct nfs_fattr *fattr)
390{
391 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
392 struct dentry *parent = dget_parent(dentry);
393 struct inode *dir = d_inode(parent);
394 const struct qstr *name = &dentry->d_name;
395 struct rpc_clnt *client;
396 struct vfsmount *mnt;
397
398 /* Look it up again to get its attributes and sec flavor */
399 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
400 dput(parent);
401 if (IS_ERR(client))
402 return ERR_CAST(client);
403
404 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
405 mnt = nfs_do_refmount(client, dentry);
406 goto out;
407 }
408
409 if (client->cl_auth->au_flavor != flavor)
410 flavor = client->cl_auth->au_flavor;
411 mnt = nfs_do_submount(dentry, fh, fattr, flavor);
412out:
413 rpc_shutdown_client(client);
414 return mnt;
415}
416
417/*
418 * Try one location from the fs_locations array.
419 *
420 * Returns zero on success, or a negative errno value.
421 */
422static int nfs4_try_replacing_one_location(struct nfs_server *server,
423 char *page, char *page2,
424 const struct nfs4_fs_location *location)
425{
426 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
427 struct net *net = rpc_net_ns(server->client);
428 struct sockaddr *sap;
429 unsigned int s;
430 size_t salen;
431 int error;
432
433 sap = kmalloc(addr_bufsize, GFP_KERNEL);
434 if (sap == NULL)
435 return -ENOMEM;
436
437 error = -ENOENT;
438 for (s = 0; s < location->nservers; s++) {
439 const struct nfs4_string *buf = &location->servers[s];
440 char *hostname;
441
442 if (buf->len <= 0 || buf->len > PAGE_SIZE)
443 continue;
444
445 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
446 continue;
447
448 salen = nfs_parse_server_name(buf->data, buf->len,
449 sap, addr_bufsize, net);
450 if (salen == 0)
451 continue;
452 rpc_set_port(sap, NFS_PORT);
453
454 error = -ENOMEM;
455 hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
456 if (hostname == NULL)
457 break;
458
459 error = nfs4_update_server(server, hostname, sap, salen, net);
460 kfree(hostname);
461 if (error == 0)
462 break;
463 }
464
465 kfree(sap);
466 return error;
467}
468
469/**
470 * nfs4_replace_transport - set up transport to destination server
471 *
472 * @server: export being migrated
473 * @locations: fs_locations array
474 *
475 * Returns zero on success, or a negative errno value.
476 *
477 * The client tries all the entries in the "locations" array, in the
478 * order returned by the server, until one works or the end of the
479 * array is reached.
480 */
481int nfs4_replace_transport(struct nfs_server *server,
482 const struct nfs4_fs_locations *locations)
483{
484 char *page = NULL, *page2 = NULL;
485 int loc, error;
486
487 error = -ENOENT;
488 if (locations == NULL || locations->nlocations <= 0)
489 goto out;
490
491 error = -ENOMEM;
492 page = (char *) __get_free_page(GFP_USER);
493 if (!page)
494 goto out;
495 page2 = (char *) __get_free_page(GFP_USER);
496 if (!page2)
497 goto out;
498
499 for (loc = 0; loc < locations->nlocations; loc++) {
500 const struct nfs4_fs_location *location =
501 &locations->locations[loc];
502
503 if (location == NULL || location->nservers <= 0 ||
504 location->rootpath.ncomponents == 0)
505 continue;
506
507 error = nfs4_try_replacing_one_location(server, page,
508 page2, location);
509 if (error == 0)
510 break;
511 }
512
513out:
514 free_page((unsigned long)page);
515 free_page((unsigned long)page2);
516 return error;
517}