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/nfs_mount.h>
15#include <linux/slab.h>
16#include <linux/string.h>
17#include <linux/sunrpc/clnt.h>
18#include <linux/sunrpc/addr.h>
19#include <linux/vfs.h>
20#include <linux/inet.h>
21#include "internal.h"
22#include "nfs4_fs.h"
23#include "dns_resolve.h"
24
25#define NFSDBG_FACILITY NFSDBG_VFS
26
27/*
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
31 */
32static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
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) {
43 const struct nfs4_string *component = &pathname->components[n];
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;
52Elong:
53 return ERR_PTR(-ENAMETOOLONG);
54}
55
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 */
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/*
81 * Determine the mount path as a string
82 */
83static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
84{
85 char *limit;
86 char *path = nfs_path(&limit, dentry, buffer, buflen,
87 NFS_PATH_CANONICAL);
88 if (!IS_ERR(path)) {
89 char *path_component = nfs_path_component(path, limit);
90 if (path_component)
91 return path_component;
92 }
93 return path;
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 */
100static int nfs4_validate_fspath(struct dentry *dentry,
101 const struct nfs4_fs_locations *locations,
102 char *page, char *page2)
103{
104 const char *path, *fs_path;
105
106 path = nfs4_path(dentry, page, PAGE_SIZE);
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",
116 __func__, path, fs_path);
117 return -ENOENT;
118 }
119
120 return 0;
121}
122
123static size_t nfs_parse_server_name(char *string, size_t len,
124 struct sockaddr *sa, size_t salen, struct net *net)
125{
126 ssize_t ret;
127
128 ret = rpc_pton(net, string, len, sa, salen);
129 if (ret == 0) {
130 ret = nfs_dns_resolve_name(net, string, len, sa, salen);
131 if (ret < 0)
132 ret = 0;
133 }
134 return ret;
135}
136
137/**
138 * nfs_find_best_sec - Find a security mechanism supported locally
139 * @server: NFS server struct
140 * @flavors: List of security tuples returned by SECINFO procedure
141 *
142 * Return an rpc client that uses the first security mechanism in
143 * "flavors" that is locally supported. The "flavors" array
144 * is searched in the order returned from the server, per RFC 3530
145 * recommendation and each flavor is checked for membership in the
146 * sec= mount option list if it exists.
147 *
148 * Return -EPERM if no matching flavor is found in the array.
149 *
150 * Please call rpc_shutdown_client() when you are done with this rpc client.
151 *
152 */
153static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
154 struct nfs_server *server,
155 struct nfs4_secinfo_flavors *flavors)
156{
157 rpc_authflavor_t pflavor;
158 struct nfs4_secinfo4 *secinfo;
159 unsigned int i;
160
161 for (i = 0; i < flavors->num_flavors; i++) {
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:
168 pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
169 &secinfo->flavor_info);
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 }
193 }
194 }
195 return ERR_PTR(-EPERM);
196}
197
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 */
209struct rpc_clnt *
210nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
211 struct qstr *name)
212{
213 struct page *page;
214 struct nfs4_secinfo_flavors *flavors;
215 struct rpc_clnt *new;
216 int err;
217
218 page = alloc_page(GFP_KERNEL);
219 if (!page)
220 return ERR_PTR(-ENOMEM);
221
222 flavors = page_address(page);
223
224 err = nfs4_proc_secinfo(inode, name, flavors);
225 if (err < 0) {
226 new = ERR_PTR(err);
227 goto out;
228 }
229
230 new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
231
232out:
233 put_page(page);
234 return new;
235}
236
237static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
238 char *page, char *page2,
239 const struct nfs4_fs_location *location)
240{
241 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
242 struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
243 struct vfsmount *mnt = ERR_PTR(-ENOENT);
244 char *mnt_path;
245 unsigned int maxbuflen;
246 unsigned int s;
247
248 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
249 if (IS_ERR(mnt_path))
250 return ERR_CAST(mnt_path);
251 mountdata->mnt_path = mnt_path;
252 maxbuflen = mnt_path - 1 - page2;
253
254 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
255 if (mountdata->addr == NULL)
256 return ERR_PTR(-ENOMEM);
257
258 for (s = 0; s < location->nservers; s++) {
259 const struct nfs4_string *buf = &location->servers[s];
260
261 if (buf->len <= 0 || buf->len >= maxbuflen)
262 continue;
263
264 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
265 continue;
266
267 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
268 mountdata->addr, addr_bufsize, net);
269 if (mountdata->addrlen == 0)
270 continue;
271
272 rpc_set_port(mountdata->addr, NFS_PORT);
273
274 memcpy(page2, buf->data, buf->len);
275 page2[buf->len] = '\0';
276 mountdata->hostname = page2;
277
278 snprintf(page, PAGE_SIZE, "%s:%s",
279 mountdata->hostname,
280 mountdata->mnt_path);
281
282 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
283 if (!IS_ERR(mnt))
284 break;
285 }
286 kfree(mountdata->addr);
287 return mnt;
288}
289
290/**
291 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
292 * @dentry - parent directory
293 * @locations - array of NFSv4 server location information
294 *
295 */
296static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
297 const struct nfs4_fs_locations *locations)
298{
299 struct vfsmount *mnt = ERR_PTR(-ENOENT);
300 struct nfs_clone_mount mountdata = {
301 .sb = dentry->d_sb,
302 .dentry = dentry,
303 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
304 };
305 char *page = NULL, *page2 = NULL;
306 int loc, error;
307
308 if (locations == NULL || locations->nlocations <= 0)
309 goto out;
310
311 dprintk("%s: referral at %pd2\n", __func__, dentry);
312
313 page = (char *) __get_free_page(GFP_USER);
314 if (!page)
315 goto out;
316
317 page2 = (char *) __get_free_page(GFP_USER);
318 if (!page2)
319 goto out;
320
321 /* Ensure fs path is a prefix of current dentry path */
322 error = nfs4_validate_fspath(dentry, locations, page, page2);
323 if (error < 0) {
324 mnt = ERR_PTR(error);
325 goto out;
326 }
327
328 for (loc = 0; loc < locations->nlocations; loc++) {
329 const struct nfs4_fs_location *location = &locations->locations[loc];
330
331 if (location == NULL || location->nservers <= 0 ||
332 location->rootpath.ncomponents == 0)
333 continue;
334
335 mnt = try_location(&mountdata, page, page2, location);
336 if (!IS_ERR(mnt))
337 break;
338 }
339
340out:
341 free_page((unsigned long) page);
342 free_page((unsigned long) page2);
343 dprintk("%s: done\n", __func__);
344 return mnt;
345}
346
347/*
348 * nfs_do_refmount - handle crossing a referral on server
349 * @dentry - dentry of referral
350 *
351 */
352static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
353{
354 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
355 struct dentry *parent;
356 struct nfs4_fs_locations *fs_locations = NULL;
357 struct page *page;
358 int err;
359
360 /* BUG_ON(IS_ROOT(dentry)); */
361 dprintk("%s: enter\n", __func__);
362
363 page = alloc_page(GFP_KERNEL);
364 if (page == NULL)
365 goto out;
366
367 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
368 if (fs_locations == NULL)
369 goto out_free;
370
371 /* Get locations */
372 mnt = ERR_PTR(-ENOENT);
373
374 parent = dget_parent(dentry);
375 dprintk("%s: getting locations for %pd2\n",
376 __func__, dentry);
377
378 err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
379 dput(parent);
380 if (err != 0 ||
381 fs_locations->nlocations <= 0 ||
382 fs_locations->fs_path.ncomponents <= 0)
383 goto out_free;
384
385 mnt = nfs_follow_referral(dentry, fs_locations);
386out_free:
387 __free_page(page);
388 kfree(fs_locations);
389out:
390 dprintk("%s: done\n", __func__);
391 return mnt;
392}
393
394struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
395 struct nfs_fh *fh, struct nfs_fattr *fattr)
396{
397 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
398 struct dentry *parent = dget_parent(dentry);
399 struct inode *dir = d_inode(parent);
400 struct qstr *name = &dentry->d_name;
401 struct rpc_clnt *client;
402 struct vfsmount *mnt;
403
404 /* Look it up again to get its attributes and sec flavor */
405 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
406 dput(parent);
407 if (IS_ERR(client))
408 return ERR_CAST(client);
409
410 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
411 mnt = nfs_do_refmount(client, dentry);
412 goto out;
413 }
414
415 if (client->cl_auth->au_flavor != flavor)
416 flavor = client->cl_auth->au_flavor;
417 mnt = nfs_do_submount(dentry, fh, fattr, flavor);
418out:
419 rpc_shutdown_client(client);
420 return mnt;
421}
422
423/*
424 * Try one location from the fs_locations array.
425 *
426 * Returns zero on success, or a negative errno value.
427 */
428static int nfs4_try_replacing_one_location(struct nfs_server *server,
429 char *page, char *page2,
430 const struct nfs4_fs_location *location)
431{
432 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
433 struct net *net = rpc_net_ns(server->client);
434 struct sockaddr *sap;
435 unsigned int s;
436 size_t salen;
437 int error;
438
439 sap = kmalloc(addr_bufsize, GFP_KERNEL);
440 if (sap == NULL)
441 return -ENOMEM;
442
443 error = -ENOENT;
444 for (s = 0; s < location->nservers; s++) {
445 const struct nfs4_string *buf = &location->servers[s];
446 char *hostname;
447
448 if (buf->len <= 0 || buf->len > PAGE_SIZE)
449 continue;
450
451 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
452 continue;
453
454 salen = nfs_parse_server_name(buf->data, buf->len,
455 sap, addr_bufsize, net);
456 if (salen == 0)
457 continue;
458 rpc_set_port(sap, NFS_PORT);
459
460 error = -ENOMEM;
461 hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
462 if (hostname == NULL)
463 break;
464
465 error = nfs4_update_server(server, hostname, sap, salen, net);
466 kfree(hostname);
467 if (error == 0)
468 break;
469 }
470
471 kfree(sap);
472 return error;
473}
474
475/**
476 * nfs4_replace_transport - set up transport to destination server
477 *
478 * @server: export being migrated
479 * @locations: fs_locations array
480 *
481 * Returns zero on success, or a negative errno value.
482 *
483 * The client tries all the entries in the "locations" array, in the
484 * order returned by the server, until one works or the end of the
485 * array is reached.
486 */
487int nfs4_replace_transport(struct nfs_server *server,
488 const struct nfs4_fs_locations *locations)
489{
490 char *page = NULL, *page2 = NULL;
491 int loc, error;
492
493 error = -ENOENT;
494 if (locations == NULL || locations->nlocations <= 0)
495 goto out;
496
497 error = -ENOMEM;
498 page = (char *) __get_free_page(GFP_USER);
499 if (!page)
500 goto out;
501 page2 = (char *) __get_free_page(GFP_USER);
502 if (!page2)
503 goto out;
504
505 for (loc = 0; loc < locations->nlocations; loc++) {
506 const struct nfs4_fs_location *location =
507 &locations->locations[loc];
508
509 if (location == NULL || location->nservers <= 0 ||
510 location->rootpath.ncomponents == 0)
511 continue;
512
513 error = nfs4_try_replacing_one_location(server, page,
514 page2, location);
515 if (error == 0)
516 break;
517 }
518
519out:
520 free_page((unsigned long)page);
521 free_page((unsigned long)page2);
522 return error;
523}
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}