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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 | ||
54ceac45 DH |
12 | #include <linux/module.h> |
13 | #include <linux/init.h> | |
14 | ||
15 | #include <linux/time.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/mm.h> | |
18 | #include <linux/string.h> | |
19 | #include <linux/stat.h> | |
20 | #include <linux/errno.h> | |
21 | #include <linux/unistd.h> | |
22 | #include <linux/sunrpc/clnt.h> | |
23 | #include <linux/sunrpc/stats.h> | |
24 | #include <linux/nfs_fs.h> | |
25 | #include <linux/nfs_mount.h> | |
26 | #include <linux/nfs4_mount.h> | |
27 | #include <linux/lockd/bind.h> | |
28 | #include <linux/smp_lock.h> | |
29 | #include <linux/seq_file.h> | |
30 | #include <linux/mount.h> | |
31 | #include <linux/nfs_idmap.h> | |
32 | #include <linux/vfs.h> | |
33 | #include <linux/namei.h> | |
6b3286ed | 34 | #include <linux/mnt_namespace.h> |
738a3519 | 35 | #include <linux/security.h> |
54ceac45 DH |
36 | |
37 | #include <asm/system.h> | |
38 | #include <asm/uaccess.h> | |
39 | ||
40 | #include "nfs4_fs.h" | |
41 | #include "delegation.h" | |
42 | #include "internal.h" | |
43 | ||
44 | #define NFSDBG_FACILITY NFSDBG_CLIENT | |
45 | #define NFS_PARANOIA 1 | |
46 | ||
47 | /* | |
48 | * get an NFS2/NFS3 root dentry from the root filehandle | |
49 | */ | |
50 | struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
51 | { | |
52 | struct nfs_server *server = NFS_SB(sb); | |
53 | struct nfs_fsinfo fsinfo; | |
54 | struct nfs_fattr fattr; | |
55 | struct dentry *mntroot; | |
56 | struct inode *inode; | |
57 | int error; | |
58 | ||
59 | /* create a dummy root dentry with dummy inode for this superblock */ | |
60 | if (!sb->s_root) { | |
61 | struct nfs_fh dummyfh; | |
62 | struct dentry *root; | |
63 | struct inode *iroot; | |
64 | ||
65 | memset(&dummyfh, 0, sizeof(dummyfh)); | |
66 | memset(&fattr, 0, sizeof(fattr)); | |
67 | nfs_fattr_init(&fattr); | |
68 | fattr.valid = NFS_ATTR_FATTR; | |
69 | fattr.type = NFDIR; | |
70 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; | |
71 | fattr.nlink = 2; | |
72 | ||
73 | iroot = nfs_fhget(sb, &dummyfh, &fattr); | |
74 | if (IS_ERR(iroot)) | |
75 | return ERR_PTR(PTR_ERR(iroot)); | |
76 | ||
77 | root = d_alloc_root(iroot); | |
78 | if (!root) { | |
79 | iput(iroot); | |
80 | return ERR_PTR(-ENOMEM); | |
81 | } | |
82 | ||
83 | sb->s_root = root; | |
84 | } | |
85 | ||
86 | /* get the actual root for this mount */ | |
87 | fsinfo.fattr = &fattr; | |
88 | ||
89 | error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
90 | if (error < 0) { | |
91 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
92 | return ERR_PTR(error); | |
93 | } | |
94 | ||
95 | inode = nfs_fhget(sb, mntfh, fsinfo.fattr); | |
96 | if (IS_ERR(inode)) { | |
97 | dprintk("nfs_get_root: get root inode failed\n"); | |
98 | return ERR_PTR(PTR_ERR(inode)); | |
99 | } | |
100 | ||
101 | /* root dentries normally start off anonymous and get spliced in later | |
102 | * if the dentry tree reaches them; however if the dentry already | |
103 | * exists, we'll pick it up at this point and use it as the root | |
104 | */ | |
105 | mntroot = d_alloc_anon(inode); | |
106 | if (!mntroot) { | |
107 | iput(inode); | |
108 | dprintk("nfs_get_root: get root dentry failed\n"); | |
109 | return ERR_PTR(-ENOMEM); | |
110 | } | |
111 | ||
738a3519 DH |
112 | security_d_instantiate(mntroot, inode); |
113 | ||
54ceac45 DH |
114 | if (!mntroot->d_op) |
115 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
116 | ||
117 | return mntroot; | |
118 | } | |
119 | ||
120 | #ifdef CONFIG_NFS_V4 | |
121 | ||
122 | /* | |
123 | * Do a simple pathwalk from the root FH of the server to the nominated target | |
124 | * of the mountpoint | |
125 | * - give error on symlinks | |
126 | * - give error on ".." occurring in the path | |
127 | * - follow traversals | |
128 | */ | |
129 | int nfs4_path_walk(struct nfs_server *server, | |
130 | struct nfs_fh *mntfh, | |
131 | const char *path) | |
132 | { | |
133 | struct nfs_fsinfo fsinfo; | |
134 | struct nfs_fattr fattr; | |
135 | struct nfs_fh lastfh; | |
136 | struct qstr name; | |
137 | int ret; | |
138 | //int referral_count = 0; | |
139 | ||
140 | dprintk("--> nfs4_path_walk(,,%s)\n", path); | |
141 | ||
142 | fsinfo.fattr = &fattr; | |
143 | nfs_fattr_init(&fattr); | |
144 | ||
145 | if (*path++ != '/') { | |
146 | dprintk("nfs4_get_root: Path does not begin with a slash\n"); | |
147 | return -EINVAL; | |
148 | } | |
149 | ||
150 | /* Start by getting the root filehandle from the server */ | |
151 | ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
152 | if (ret < 0) { | |
153 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); | |
154 | return ret; | |
155 | } | |
156 | ||
157 | if (fattr.type != NFDIR) { | |
158 | printk(KERN_ERR "nfs4_get_root:" | |
159 | " getroot encountered non-directory\n"); | |
160 | return -ENOTDIR; | |
161 | } | |
162 | ||
163 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { | |
164 | printk(KERN_ERR "nfs4_get_root:" | |
165 | " getroot obtained referral\n"); | |
166 | return -EREMOTE; | |
167 | } | |
168 | ||
169 | next_component: | |
170 | dprintk("Next: %s\n", path); | |
171 | ||
172 | /* extract the next bit of the path */ | |
173 | if (!*path) | |
174 | goto path_walk_complete; | |
175 | ||
176 | name.name = path; | |
177 | while (*path && *path != '/') | |
178 | path++; | |
179 | name.len = path - (const char *) name.name; | |
180 | ||
181 | eat_dot_dir: | |
182 | while (*path == '/') | |
183 | path++; | |
184 | ||
185 | if (path[0] == '.' && (path[1] == '/' || !path[1])) { | |
186 | path += 2; | |
187 | goto eat_dot_dir; | |
188 | } | |
189 | ||
190 | if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2]) | |
191 | ) { | |
192 | printk(KERN_ERR "nfs4_get_root:" | |
193 | " Mount path contains reference to \"..\"\n"); | |
194 | return -EINVAL; | |
195 | } | |
196 | ||
197 | /* lookup the next FH in the sequence */ | |
198 | memcpy(&lastfh, mntfh, sizeof(lastfh)); | |
199 | ||
200 | dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path); | |
201 | ||
202 | ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name, | |
203 | mntfh, &fattr); | |
204 | if (ret < 0) { | |
205 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); | |
206 | return ret; | |
207 | } | |
208 | ||
209 | if (fattr.type != NFDIR) { | |
210 | printk(KERN_ERR "nfs4_get_root:" | |
211 | " lookupfh encountered non-directory\n"); | |
212 | return -ENOTDIR; | |
213 | } | |
214 | ||
215 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { | |
216 | printk(KERN_ERR "nfs4_get_root:" | |
217 | " lookupfh obtained referral\n"); | |
218 | return -EREMOTE; | |
219 | } | |
220 | ||
221 | goto next_component; | |
222 | ||
223 | path_walk_complete: | |
224 | memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid)); | |
225 | dprintk("<-- nfs4_path_walk() = 0\n"); | |
226 | return 0; | |
227 | } | |
228 | ||
229 | /* | |
230 | * get an NFS4 root dentry from the root filehandle | |
231 | */ | |
232 | struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
233 | { | |
234 | struct nfs_server *server = NFS_SB(sb); | |
235 | struct nfs_fattr fattr; | |
236 | struct dentry *mntroot; | |
237 | struct inode *inode; | |
238 | int error; | |
239 | ||
240 | dprintk("--> nfs4_get_root()\n"); | |
241 | ||
242 | /* create a dummy root dentry with dummy inode for this superblock */ | |
243 | if (!sb->s_root) { | |
244 | struct nfs_fh dummyfh; | |
245 | struct dentry *root; | |
246 | struct inode *iroot; | |
247 | ||
248 | memset(&dummyfh, 0, sizeof(dummyfh)); | |
249 | memset(&fattr, 0, sizeof(fattr)); | |
250 | nfs_fattr_init(&fattr); | |
251 | fattr.valid = NFS_ATTR_FATTR; | |
252 | fattr.type = NFDIR; | |
253 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; | |
254 | fattr.nlink = 2; | |
255 | ||
256 | iroot = nfs_fhget(sb, &dummyfh, &fattr); | |
257 | if (IS_ERR(iroot)) | |
258 | return ERR_PTR(PTR_ERR(iroot)); | |
259 | ||
260 | root = d_alloc_root(iroot); | |
261 | if (!root) { | |
262 | iput(iroot); | |
263 | return ERR_PTR(-ENOMEM); | |
264 | } | |
265 | ||
266 | sb->s_root = root; | |
267 | } | |
268 | ||
269 | /* get the info about the server and filesystem */ | |
270 | error = nfs4_server_capabilities(server, mntfh); | |
271 | if (error < 0) { | |
272 | dprintk("nfs_get_root: getcaps error = %d\n", | |
273 | -error); | |
274 | return ERR_PTR(error); | |
275 | } | |
276 | ||
277 | /* get the actual root for this mount */ | |
278 | error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr); | |
279 | if (error < 0) { | |
280 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
281 | return ERR_PTR(error); | |
282 | } | |
283 | ||
284 | inode = nfs_fhget(sb, mntfh, &fattr); | |
285 | if (IS_ERR(inode)) { | |
286 | dprintk("nfs_get_root: get root inode failed\n"); | |
287 | return ERR_PTR(PTR_ERR(inode)); | |
288 | } | |
289 | ||
290 | /* root dentries normally start off anonymous and get spliced in later | |
291 | * if the dentry tree reaches them; however if the dentry already | |
292 | * exists, we'll pick it up at this point and use it as the root | |
293 | */ | |
294 | mntroot = d_alloc_anon(inode); | |
295 | if (!mntroot) { | |
296 | iput(inode); | |
297 | dprintk("nfs_get_root: get root dentry failed\n"); | |
298 | return ERR_PTR(-ENOMEM); | |
299 | } | |
300 | ||
738a3519 DH |
301 | security_d_instantiate(mntroot, inode); |
302 | ||
54ceac45 DH |
303 | if (!mntroot->d_op) |
304 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
305 | ||
306 | dprintk("<-- nfs4_get_root()\n"); | |
307 | return mntroot; | |
308 | } | |
309 | ||
310 | #endif /* CONFIG_NFS_V4 */ |