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10#include <linux/dcache.h>
11#include <linux/mount.h>
12#include <linux/namei.h>
13#include <linux/nfs_fs.h>
14#include <linux/string.h>
15#include <linux/sunrpc/clnt.h>
16#include <linux/vfs.h>
17#include <linux/inet.h>
18#include "internal.h"
19#include "nfs4_fs.h"
20#include "dns_resolve.h"
21
22#define NFSDBG_FACILITY NFSDBG_VFS
23
24
25
26
27
28
29static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
30 char *buffer, ssize_t buflen)
31{
32 char *end = buffer + buflen;
33 int n;
34
35 *--end = '\0';
36 buflen--;
37
38 n = pathname->ncomponents;
39 while (--n >= 0) {
40 const struct nfs4_string *component = &pathname->components[n];
41 buflen -= component->len + 1;
42 if (buflen < 0)
43 goto Elong;
44 end -= component->len;
45 memcpy(end, component->data, component->len);
46 *--end = '/';
47 }
48 return end;
49Elong:
50 return ERR_PTR(-ENAMETOOLONG);
51}
52
53
54
55
56static char *nfs4_path(const struct vfsmount *mnt_parent,
57 const struct dentry *dentry,
58 char *buffer, ssize_t buflen)
59{
60 const char *srvpath;
61
62 srvpath = strchr(mnt_parent->mnt_devname, ':');
63 if (srvpath)
64 srvpath++;
65 else
66 srvpath = mnt_parent->mnt_devname;
67
68 return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
69}
70
71
72
73
74
75static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
76 const struct dentry *dentry,
77 const struct nfs4_fs_locations *locations,
78 char *page, char *page2)
79{
80 const char *path, *fs_path;
81
82 path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
83 if (IS_ERR(path))
84 return PTR_ERR(path);
85
86 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
87 if (IS_ERR(fs_path))
88 return PTR_ERR(fs_path);
89
90 if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
91 dprintk("%s: path %s does not begin with fsroot %s\n",
92 __func__, path, fs_path);
93 return -ENOENT;
94 }
95
96 return 0;
97}
98
99static size_t nfs_parse_server_name(char *string, size_t len,
100 struct sockaddr *sa, size_t salen)
101{
102 ssize_t ret;
103
104 ret = rpc_pton(string, len, sa, salen);
105 if (ret == 0) {
106 ret = nfs_dns_resolve_name(string, len, sa, salen);
107 if (ret < 0)
108 ret = 0;
109 }
110 return ret;
111}
112
113static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
114 char *page, char *page2,
115 const struct nfs4_fs_location *location)
116{
117 struct vfsmount *mnt = ERR_PTR(-ENOENT);
118 char *mnt_path;
119 unsigned int maxbuflen;
120 unsigned int s;
121
122 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
123 if (IS_ERR(mnt_path))
124 return ERR_CAST(mnt_path);
125 mountdata->mnt_path = mnt_path;
126 maxbuflen = mnt_path - 1 - page2;
127
128 for (s = 0; s < location->nservers; s++) {
129 const struct nfs4_string *buf = &location->servers[s];
130 struct sockaddr_storage addr;
131
132 if (buf->len <= 0 || buf->len >= maxbuflen)
133 continue;
134
135 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
136 continue;
137
138 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
139 (struct sockaddr *)&addr, sizeof(addr));
140 if (mountdata->addrlen == 0)
141 continue;
142
143 mountdata->addr = (struct sockaddr *)&addr;
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 return mnt;
159}
160
161
162
163
164
165
166
167
168static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
169 const struct dentry *dentry,
170 const struct nfs4_fs_locations *locations)
171{
172 struct vfsmount *mnt = ERR_PTR(-ENOENT);
173 struct nfs_clone_mount mountdata = {
174 .sb = mnt_parent->mnt_sb,
175 .dentry = dentry,
176 .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
177 };
178 char *page = NULL, *page2 = NULL;
179 int loc, error;
180
181 if (locations == NULL || locations->nlocations <= 0)
182 goto out;
183
184 dprintk("%s: referral at %s/%s\n", __func__,
185 dentry->d_parent->d_name.name, dentry->d_name.name);
186
187 page = (char *) __get_free_page(GFP_USER);
188 if (!page)
189 goto out;
190
191 page2 = (char *) __get_free_page(GFP_USER);
192 if (!page2)
193 goto out;
194
195
196 error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
197 if (error < 0) {
198 mnt = ERR_PTR(error);
199 goto out;
200 }
201
202 for (loc = 0; loc < locations->nlocations; loc++) {
203 const struct nfs4_fs_location *location = &locations->locations[loc];
204
205 if (location == NULL || location->nservers <= 0 ||
206 location->rootpath.ncomponents == 0)
207 continue;
208
209 mnt = try_location(&mountdata, page, page2, location);
210 if (!IS_ERR(mnt))
211 break;
212 }
213
214out:
215 free_page((unsigned long) page);
216 free_page((unsigned long) page2);
217 dprintk("%s: done\n", __func__);
218 return mnt;
219}
220
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224
225
226
227struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
228{
229 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
230 struct dentry *parent;
231 struct nfs4_fs_locations *fs_locations = NULL;
232 struct page *page;
233 int err;
234
235
236 dprintk("%s: enter\n", __func__);
237
238 page = alloc_page(GFP_KERNEL);
239 if (page == NULL)
240 goto out;
241
242 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
243 if (fs_locations == NULL)
244 goto out_free;
245
246
247 mnt = ERR_PTR(-ENOENT);
248
249 parent = dget_parent(dentry);
250 dprintk("%s: getting locations for %s/%s\n",
251 __func__, parent->d_name.name, dentry->d_name.name);
252
253 err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
254 dput(parent);
255 if (err != 0 ||
256 fs_locations->nlocations <= 0 ||
257 fs_locations->fs_path.ncomponents <= 0)
258 goto out_free;
259
260 mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
261out_free:
262 __free_page(page);
263 kfree(fs_locations);
264out:
265 dprintk("%s: done\n", __func__);
266 return mnt;
267}
268
