blob: d1cbf0a0fbb2d457c92c964958e96dc2d9f56839 [file] [log] [blame]
David Howells54ceac42006-08-22 20:06:13 -04001/* 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
David Howells54ceac42006-08-22 20:06:13 -040012#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>
David Howells54ceac42006-08-22 20:06:13 -040028#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>
Kirill Korotaev6b3286e2006-12-08 02:37:56 -080033#include <linux/mnt_namespace.h>
David Howells738a3512006-07-30 14:58:27 -040034#include <linux/security.h>
David Howells54ceac42006-08-22 20:06:13 -040035
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
David Howells54ceac42006-08-22 20:06:13 -040044
45/*
46 * get an NFS2/NFS3 root dentry from the root filehandle
47 */
48struct 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
David Howells738a3512006-07-30 14:58:27 -0400110 security_d_instantiate(mntroot, inode);
111
David Howells54ceac42006-08-22 20:06:13 -0400112 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 */
127int 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;
David Howells54ceac42006-08-22 20:06:13 -0400136
137 dprintk("--> nfs4_path_walk(,,%s)\n", path);
138
139 fsinfo.fattr = &fattr;
140 nfs_fattr_init(&fattr);
141
Trond Myklebustfaebf4e2007-01-13 02:28:11 -0500142 /* Eat leading slashes */
143 while (*path == '/')
144 path++;
David Howells54ceac42006-08-22 20:06:13 -0400145
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
Trond Myklebustfaebf4e2007-01-13 02:28:11 -0500159 /* FIXME: It is quite valid for the server to return a referral here */
David Howells54ceac42006-08-22 20:06:13 -0400160 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
166next_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
178eat_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
Trond Myklebustfaebf4e2007-01-13 02:28:11 -0500187 /* FIXME: Why shouldn't the user be able to use ".." in the path? */
David Howells54ceac42006-08-22 20:06:13 -0400188 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
Trond Myklebustfaebf4e2007-01-13 02:28:11 -0500213 /* FIXME: Referrals are quite valid here too */
David Howells54ceac42006-08-22 20:06:13 -0400214 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
222path_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 */
231struct 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
David Howells738a3512006-07-30 14:58:27 -0400300 security_d_instantiate(mntroot, inode);
301
David Howells54ceac42006-08-22 20:06:13 -0400302 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 */