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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> | |
54ceac45 DH |
28 | #include <linux/seq_file.h> |
29 | #include <linux/mount.h> | |
30 | #include <linux/nfs_idmap.h> | |
31 | #include <linux/vfs.h> | |
32 | #include <linux/namei.h> | |
6b3286ed | 33 | #include <linux/mnt_namespace.h> |
738a3519 | 34 | #include <linux/security.h> |
54ceac45 DH |
35 | |
36 | #include <asm/system.h> | |
37 | #include <asm/uaccess.h> | |
38 | ||
39 | #include "nfs4_fs.h" | |
40 | #include "delegation.h" | |
41 | #include "internal.h" | |
42 | ||
43 | #define NFSDBG_FACILITY NFSDBG_CLIENT | |
54ceac45 DH |
44 | |
45 | /* | |
46 | * get an NFS2/NFS3 root dentry from the root filehandle | |
47 | */ | |
48 | struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
49 | { | |
50 | struct nfs_server *server = NFS_SB(sb); | |
51 | struct nfs_fsinfo fsinfo; | |
52 | struct nfs_fattr fattr; | |
53 | struct dentry *mntroot; | |
54 | struct inode *inode; | |
55 | int error; | |
56 | ||
57 | /* create a dummy root dentry with dummy inode for this superblock */ | |
58 | if (!sb->s_root) { | |
59 | struct nfs_fh dummyfh; | |
60 | struct dentry *root; | |
61 | struct inode *iroot; | |
62 | ||
63 | memset(&dummyfh, 0, sizeof(dummyfh)); | |
64 | memset(&fattr, 0, sizeof(fattr)); | |
65 | nfs_fattr_init(&fattr); | |
66 | fattr.valid = NFS_ATTR_FATTR; | |
67 | fattr.type = NFDIR; | |
68 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; | |
69 | fattr.nlink = 2; | |
70 | ||
71 | iroot = nfs_fhget(sb, &dummyfh, &fattr); | |
72 | if (IS_ERR(iroot)) | |
73 | return ERR_PTR(PTR_ERR(iroot)); | |
74 | ||
75 | root = d_alloc_root(iroot); | |
76 | if (!root) { | |
77 | iput(iroot); | |
78 | return ERR_PTR(-ENOMEM); | |
79 | } | |
80 | ||
81 | sb->s_root = root; | |
82 | } | |
83 | ||
84 | /* get the actual root for this mount */ | |
85 | fsinfo.fattr = &fattr; | |
86 | ||
87 | error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
88 | if (error < 0) { | |
89 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
90 | return ERR_PTR(error); | |
91 | } | |
92 | ||
93 | inode = nfs_fhget(sb, mntfh, fsinfo.fattr); | |
94 | if (IS_ERR(inode)) { | |
95 | dprintk("nfs_get_root: get root inode failed\n"); | |
96 | return ERR_PTR(PTR_ERR(inode)); | |
97 | } | |
98 | ||
99 | /* root dentries normally start off anonymous and get spliced in later | |
100 | * if the dentry tree reaches them; however if the dentry already | |
101 | * exists, we'll pick it up at this point and use it as the root | |
102 | */ | |
103 | mntroot = d_alloc_anon(inode); | |
104 | if (!mntroot) { | |
105 | iput(inode); | |
106 | dprintk("nfs_get_root: get root dentry failed\n"); | |
107 | return ERR_PTR(-ENOMEM); | |
108 | } | |
109 | ||
738a3519 DH |
110 | security_d_instantiate(mntroot, inode); |
111 | ||
54ceac45 DH |
112 | if (!mntroot->d_op) |
113 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
114 | ||
115 | return mntroot; | |
116 | } | |
117 | ||
118 | #ifdef CONFIG_NFS_V4 | |
119 | ||
120 | /* | |
121 | * Do a simple pathwalk from the root FH of the server to the nominated target | |
122 | * of the mountpoint | |
123 | * - give error on symlinks | |
124 | * - give error on ".." occurring in the path | |
125 | * - follow traversals | |
126 | */ | |
127 | int nfs4_path_walk(struct nfs_server *server, | |
128 | struct nfs_fh *mntfh, | |
129 | const char *path) | |
130 | { | |
131 | struct nfs_fsinfo fsinfo; | |
132 | struct nfs_fattr fattr; | |
133 | struct nfs_fh lastfh; | |
134 | struct qstr name; | |
135 | int ret; | |
54ceac45 DH |
136 | |
137 | dprintk("--> nfs4_path_walk(,,%s)\n", path); | |
138 | ||
139 | fsinfo.fattr = &fattr; | |
140 | nfs_fattr_init(&fattr); | |
141 | ||
faebf4e2 TM |
142 | /* Eat leading slashes */ |
143 | while (*path == '/') | |
144 | path++; | |
54ceac45 DH |
145 | |
146 | /* Start by getting the root filehandle from the server */ | |
147 | ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
148 | if (ret < 0) { | |
149 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); | |
150 | return ret; | |
151 | } | |
152 | ||
153 | if (fattr.type != NFDIR) { | |
154 | printk(KERN_ERR "nfs4_get_root:" | |
155 | " getroot encountered non-directory\n"); | |
156 | return -ENOTDIR; | |
157 | } | |
158 | ||
faebf4e2 | 159 | /* FIXME: It is quite valid for the server to return a referral here */ |
54ceac45 DH |
160 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { |
161 | printk(KERN_ERR "nfs4_get_root:" | |
162 | " getroot obtained referral\n"); | |
163 | return -EREMOTE; | |
164 | } | |
165 | ||
166 | next_component: | |
167 | dprintk("Next: %s\n", path); | |
168 | ||
169 | /* extract the next bit of the path */ | |
170 | if (!*path) | |
171 | goto path_walk_complete; | |
172 | ||
173 | name.name = path; | |
174 | while (*path && *path != '/') | |
175 | path++; | |
176 | name.len = path - (const char *) name.name; | |
177 | ||
178 | eat_dot_dir: | |
179 | while (*path == '/') | |
180 | path++; | |
181 | ||
182 | if (path[0] == '.' && (path[1] == '/' || !path[1])) { | |
183 | path += 2; | |
184 | goto eat_dot_dir; | |
185 | } | |
186 | ||
faebf4e2 | 187 | /* FIXME: Why shouldn't the user be able to use ".." in the path? */ |
54ceac45 DH |
188 | if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2]) |
189 | ) { | |
190 | printk(KERN_ERR "nfs4_get_root:" | |
191 | " Mount path contains reference to \"..\"\n"); | |
192 | return -EINVAL; | |
193 | } | |
194 | ||
195 | /* lookup the next FH in the sequence */ | |
196 | memcpy(&lastfh, mntfh, sizeof(lastfh)); | |
197 | ||
198 | dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path); | |
199 | ||
200 | ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name, | |
201 | mntfh, &fattr); | |
202 | if (ret < 0) { | |
203 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); | |
204 | return ret; | |
205 | } | |
206 | ||
207 | if (fattr.type != NFDIR) { | |
208 | printk(KERN_ERR "nfs4_get_root:" | |
209 | " lookupfh encountered non-directory\n"); | |
210 | return -ENOTDIR; | |
211 | } | |
212 | ||
faebf4e2 | 213 | /* FIXME: Referrals are quite valid here too */ |
54ceac45 DH |
214 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { |
215 | printk(KERN_ERR "nfs4_get_root:" | |
216 | " lookupfh obtained referral\n"); | |
217 | return -EREMOTE; | |
218 | } | |
219 | ||
220 | goto next_component; | |
221 | ||
222 | path_walk_complete: | |
223 | memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid)); | |
224 | dprintk("<-- nfs4_path_walk() = 0\n"); | |
225 | return 0; | |
226 | } | |
227 | ||
228 | /* | |
229 | * get an NFS4 root dentry from the root filehandle | |
230 | */ | |
231 | struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
232 | { | |
233 | struct nfs_server *server = NFS_SB(sb); | |
234 | struct nfs_fattr fattr; | |
235 | struct dentry *mntroot; | |
236 | struct inode *inode; | |
237 | int error; | |
238 | ||
239 | dprintk("--> nfs4_get_root()\n"); | |
240 | ||
241 | /* create a dummy root dentry with dummy inode for this superblock */ | |
242 | if (!sb->s_root) { | |
243 | struct nfs_fh dummyfh; | |
244 | struct dentry *root; | |
245 | struct inode *iroot; | |
246 | ||
247 | memset(&dummyfh, 0, sizeof(dummyfh)); | |
248 | memset(&fattr, 0, sizeof(fattr)); | |
249 | nfs_fattr_init(&fattr); | |
250 | fattr.valid = NFS_ATTR_FATTR; | |
251 | fattr.type = NFDIR; | |
252 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; | |
253 | fattr.nlink = 2; | |
254 | ||
255 | iroot = nfs_fhget(sb, &dummyfh, &fattr); | |
256 | if (IS_ERR(iroot)) | |
257 | return ERR_PTR(PTR_ERR(iroot)); | |
258 | ||
259 | root = d_alloc_root(iroot); | |
260 | if (!root) { | |
261 | iput(iroot); | |
262 | return ERR_PTR(-ENOMEM); | |
263 | } | |
264 | ||
265 | sb->s_root = root; | |
266 | } | |
267 | ||
268 | /* get the info about the server and filesystem */ | |
269 | error = nfs4_server_capabilities(server, mntfh); | |
270 | if (error < 0) { | |
271 | dprintk("nfs_get_root: getcaps error = %d\n", | |
272 | -error); | |
273 | return ERR_PTR(error); | |
274 | } | |
275 | ||
276 | /* get the actual root for this mount */ | |
277 | error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr); | |
278 | if (error < 0) { | |
279 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
280 | return ERR_PTR(error); | |
281 | } | |
282 | ||
283 | inode = nfs_fhget(sb, mntfh, &fattr); | |
284 | if (IS_ERR(inode)) { | |
285 | dprintk("nfs_get_root: get root inode failed\n"); | |
286 | return ERR_PTR(PTR_ERR(inode)); | |
287 | } | |
288 | ||
289 | /* root dentries normally start off anonymous and get spliced in later | |
290 | * if the dentry tree reaches them; however if the dentry already | |
291 | * exists, we'll pick it up at this point and use it as the root | |
292 | */ | |
293 | mntroot = d_alloc_anon(inode); | |
294 | if (!mntroot) { | |
295 | iput(inode); | |
296 | dprintk("nfs_get_root: get root dentry failed\n"); | |
297 | return ERR_PTR(-ENOMEM); | |
298 | } | |
299 | ||
738a3519 DH |
300 | security_d_instantiate(mntroot, inode); |
301 | ||
54ceac45 DH |
302 | if (!mntroot->d_op) |
303 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
304 | ||
305 | dprintk("<-- nfs4_get_root()\n"); | |
306 | return mntroot; | |
307 | } | |
308 | ||
309 | #endif /* CONFIG_NFS_V4 */ |