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54ceac45 DH |
1 | /* getroot.c: get the root dentry for an NFS mount |
2 | * | |
3 | * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #include <linux/config.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/init.h> | |
15 | ||
16 | #include <linux/time.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/string.h> | |
20 | #include <linux/stat.h> | |
21 | #include <linux/errno.h> | |
22 | #include <linux/unistd.h> | |
23 | #include <linux/sunrpc/clnt.h> | |
24 | #include <linux/sunrpc/stats.h> | |
25 | #include <linux/nfs_fs.h> | |
26 | #include <linux/nfs_mount.h> | |
27 | #include <linux/nfs4_mount.h> | |
28 | #include <linux/lockd/bind.h> | |
29 | #include <linux/smp_lock.h> | |
30 | #include <linux/seq_file.h> | |
31 | #include <linux/mount.h> | |
32 | #include <linux/nfs_idmap.h> | |
33 | #include <linux/vfs.h> | |
34 | #include <linux/namei.h> | |
35 | #include <linux/namespace.h> | |
738a3519 | 36 | #include <linux/security.h> |
54ceac45 DH |
37 | |
38 | #include <asm/system.h> | |
39 | #include <asm/uaccess.h> | |
40 | ||
41 | #include "nfs4_fs.h" | |
42 | #include "delegation.h" | |
43 | #include "internal.h" | |
44 | ||
45 | #define NFSDBG_FACILITY NFSDBG_CLIENT | |
46 | #define NFS_PARANOIA 1 | |
47 | ||
48 | /* | |
49 | * get an NFS2/NFS3 root dentry from the root filehandle | |
50 | */ | |
51 | struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
52 | { | |
53 | struct nfs_server *server = NFS_SB(sb); | |
54 | struct nfs_fsinfo fsinfo; | |
55 | struct nfs_fattr fattr; | |
56 | struct dentry *mntroot; | |
57 | struct inode *inode; | |
58 | int error; | |
59 | ||
60 | /* create a dummy root dentry with dummy inode for this superblock */ | |
61 | if (!sb->s_root) { | |
62 | struct nfs_fh dummyfh; | |
63 | struct dentry *root; | |
64 | struct inode *iroot; | |
65 | ||
66 | memset(&dummyfh, 0, sizeof(dummyfh)); | |
67 | memset(&fattr, 0, sizeof(fattr)); | |
68 | nfs_fattr_init(&fattr); | |
69 | fattr.valid = NFS_ATTR_FATTR; | |
70 | fattr.type = NFDIR; | |
71 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; | |
72 | fattr.nlink = 2; | |
73 | ||
74 | iroot = nfs_fhget(sb, &dummyfh, &fattr); | |
75 | if (IS_ERR(iroot)) | |
76 | return ERR_PTR(PTR_ERR(iroot)); | |
77 | ||
78 | root = d_alloc_root(iroot); | |
79 | if (!root) { | |
80 | iput(iroot); | |
81 | return ERR_PTR(-ENOMEM); | |
82 | } | |
83 | ||
84 | sb->s_root = root; | |
85 | } | |
86 | ||
87 | /* get the actual root for this mount */ | |
88 | fsinfo.fattr = &fattr; | |
89 | ||
90 | error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
91 | if (error < 0) { | |
92 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
93 | return ERR_PTR(error); | |
94 | } | |
95 | ||
96 | inode = nfs_fhget(sb, mntfh, fsinfo.fattr); | |
97 | if (IS_ERR(inode)) { | |
98 | dprintk("nfs_get_root: get root inode failed\n"); | |
99 | return ERR_PTR(PTR_ERR(inode)); | |
100 | } | |
101 | ||
102 | /* root dentries normally start off anonymous and get spliced in later | |
103 | * if the dentry tree reaches them; however if the dentry already | |
104 | * exists, we'll pick it up at this point and use it as the root | |
105 | */ | |
106 | mntroot = d_alloc_anon(inode); | |
107 | if (!mntroot) { | |
108 | iput(inode); | |
109 | dprintk("nfs_get_root: get root dentry failed\n"); | |
110 | return ERR_PTR(-ENOMEM); | |
111 | } | |
112 | ||
738a3519 DH |
113 | security_d_instantiate(mntroot, inode); |
114 | ||
54ceac45 DH |
115 | if (!mntroot->d_op) |
116 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
117 | ||
118 | return mntroot; | |
119 | } | |
120 | ||
121 | #ifdef CONFIG_NFS_V4 | |
122 | ||
123 | /* | |
124 | * Do a simple pathwalk from the root FH of the server to the nominated target | |
125 | * of the mountpoint | |
126 | * - give error on symlinks | |
127 | * - give error on ".." occurring in the path | |
128 | * - follow traversals | |
129 | */ | |
130 | int nfs4_path_walk(struct nfs_server *server, | |
131 | struct nfs_fh *mntfh, | |
132 | const char *path) | |
133 | { | |
134 | struct nfs_fsinfo fsinfo; | |
135 | struct nfs_fattr fattr; | |
136 | struct nfs_fh lastfh; | |
137 | struct qstr name; | |
138 | int ret; | |
139 | //int referral_count = 0; | |
140 | ||
141 | dprintk("--> nfs4_path_walk(,,%s)\n", path); | |
142 | ||
143 | fsinfo.fattr = &fattr; | |
144 | nfs_fattr_init(&fattr); | |
145 | ||
146 | if (*path++ != '/') { | |
147 | dprintk("nfs4_get_root: Path does not begin with a slash\n"); | |
148 | return -EINVAL; | |
149 | } | |
150 | ||
151 | /* Start by getting the root filehandle from the server */ | |
152 | ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
153 | if (ret < 0) { | |
154 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); | |
155 | return ret; | |
156 | } | |
157 | ||
158 | if (fattr.type != NFDIR) { | |
159 | printk(KERN_ERR "nfs4_get_root:" | |
160 | " getroot encountered non-directory\n"); | |
161 | return -ENOTDIR; | |
162 | } | |
163 | ||
164 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { | |
165 | printk(KERN_ERR "nfs4_get_root:" | |
166 | " getroot obtained referral\n"); | |
167 | return -EREMOTE; | |
168 | } | |
169 | ||
170 | next_component: | |
171 | dprintk("Next: %s\n", path); | |
172 | ||
173 | /* extract the next bit of the path */ | |
174 | if (!*path) | |
175 | goto path_walk_complete; | |
176 | ||
177 | name.name = path; | |
178 | while (*path && *path != '/') | |
179 | path++; | |
180 | name.len = path - (const char *) name.name; | |
181 | ||
182 | eat_dot_dir: | |
183 | while (*path == '/') | |
184 | path++; | |
185 | ||
186 | if (path[0] == '.' && (path[1] == '/' || !path[1])) { | |
187 | path += 2; | |
188 | goto eat_dot_dir; | |
189 | } | |
190 | ||
191 | if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2]) | |
192 | ) { | |
193 | printk(KERN_ERR "nfs4_get_root:" | |
194 | " Mount path contains reference to \"..\"\n"); | |
195 | return -EINVAL; | |
196 | } | |
197 | ||
198 | /* lookup the next FH in the sequence */ | |
199 | memcpy(&lastfh, mntfh, sizeof(lastfh)); | |
200 | ||
201 | dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path); | |
202 | ||
203 | ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name, | |
204 | mntfh, &fattr); | |
205 | if (ret < 0) { | |
206 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); | |
207 | return ret; | |
208 | } | |
209 | ||
210 | if (fattr.type != NFDIR) { | |
211 | printk(KERN_ERR "nfs4_get_root:" | |
212 | " lookupfh encountered non-directory\n"); | |
213 | return -ENOTDIR; | |
214 | } | |
215 | ||
216 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { | |
217 | printk(KERN_ERR "nfs4_get_root:" | |
218 | " lookupfh obtained referral\n"); | |
219 | return -EREMOTE; | |
220 | } | |
221 | ||
222 | goto next_component; | |
223 | ||
224 | path_walk_complete: | |
225 | memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid)); | |
226 | dprintk("<-- nfs4_path_walk() = 0\n"); | |
227 | return 0; | |
228 | } | |
229 | ||
230 | /* | |
231 | * get an NFS4 root dentry from the root filehandle | |
232 | */ | |
233 | struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
234 | { | |
235 | struct nfs_server *server = NFS_SB(sb); | |
236 | struct nfs_fattr fattr; | |
237 | struct dentry *mntroot; | |
238 | struct inode *inode; | |
239 | int error; | |
240 | ||
241 | dprintk("--> nfs4_get_root()\n"); | |
242 | ||
243 | /* create a dummy root dentry with dummy inode for this superblock */ | |
244 | if (!sb->s_root) { | |
245 | struct nfs_fh dummyfh; | |
246 | struct dentry *root; | |
247 | struct inode *iroot; | |
248 | ||
249 | memset(&dummyfh, 0, sizeof(dummyfh)); | |
250 | memset(&fattr, 0, sizeof(fattr)); | |
251 | nfs_fattr_init(&fattr); | |
252 | fattr.valid = NFS_ATTR_FATTR; | |
253 | fattr.type = NFDIR; | |
254 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; | |
255 | fattr.nlink = 2; | |
256 | ||
257 | iroot = nfs_fhget(sb, &dummyfh, &fattr); | |
258 | if (IS_ERR(iroot)) | |
259 | return ERR_PTR(PTR_ERR(iroot)); | |
260 | ||
261 | root = d_alloc_root(iroot); | |
262 | if (!root) { | |
263 | iput(iroot); | |
264 | return ERR_PTR(-ENOMEM); | |
265 | } | |
266 | ||
267 | sb->s_root = root; | |
268 | } | |
269 | ||
270 | /* get the info about the server and filesystem */ | |
271 | error = nfs4_server_capabilities(server, mntfh); | |
272 | if (error < 0) { | |
273 | dprintk("nfs_get_root: getcaps error = %d\n", | |
274 | -error); | |
275 | return ERR_PTR(error); | |
276 | } | |
277 | ||
278 | /* get the actual root for this mount */ | |
279 | error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr); | |
280 | if (error < 0) { | |
281 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
282 | return ERR_PTR(error); | |
283 | } | |
284 | ||
285 | inode = nfs_fhget(sb, mntfh, &fattr); | |
286 | if (IS_ERR(inode)) { | |
287 | dprintk("nfs_get_root: get root inode failed\n"); | |
288 | return ERR_PTR(PTR_ERR(inode)); | |
289 | } | |
290 | ||
291 | /* root dentries normally start off anonymous and get spliced in later | |
292 | * if the dentry tree reaches them; however if the dentry already | |
293 | * exists, we'll pick it up at this point and use it as the root | |
294 | */ | |
295 | mntroot = d_alloc_anon(inode); | |
296 | if (!mntroot) { | |
297 | iput(inode); | |
298 | dprintk("nfs_get_root: get root dentry failed\n"); | |
299 | return ERR_PTR(-ENOMEM); | |
300 | } | |
301 | ||
738a3519 DH |
302 | security_d_instantiate(mntroot, inode); |
303 | ||
54ceac45 DH |
304 | if (!mntroot->d_op) |
305 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
306 | ||
307 | dprintk("<-- nfs4_get_root()\n"); | |
308 | return mntroot; | |
309 | } | |
310 | ||
311 | #endif /* CONFIG_NFS_V4 */ |