1 /* getroot.c: get the root dentry for an NFS mount
3 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 #include <linux/config.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
16 #include <linux/time.h>
17 #include <linux/kernel.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>
36 #include <linux/security.h>
38 #include <asm/system.h>
39 #include <asm/uaccess.h>
42 #include "delegation.h"
45 #define NFSDBG_FACILITY NFSDBG_CLIENT
46 #define NFS_PARANOIA 1
49 * get an NFS2/NFS3 root dentry from the root filehandle
51 struct dentry
*nfs_get_root(struct super_block
*sb
, struct nfs_fh
*mntfh
)
53 struct nfs_server
*server
= NFS_SB(sb
);
54 struct nfs_fsinfo fsinfo
;
55 struct nfs_fattr fattr
;
56 struct dentry
*mntroot
;
60 /* create a dummy root dentry with dummy inode for this superblock */
62 struct nfs_fh dummyfh
;
66 memset(&dummyfh
, 0, sizeof(dummyfh
));
67 memset(&fattr
, 0, sizeof(fattr
));
68 nfs_fattr_init(&fattr
);
69 fattr
.valid
= NFS_ATTR_FATTR
;
71 fattr
.mode
= S_IFDIR
| S_IRUSR
| S_IWUSR
;
74 iroot
= nfs_fhget(sb
, &dummyfh
, &fattr
);
76 return ERR_PTR(PTR_ERR(iroot
));
78 root
= d_alloc_root(iroot
);
81 return ERR_PTR(-ENOMEM
);
87 /* get the actual root for this mount */
88 fsinfo
.fattr
= &fattr
;
90 error
= server
->nfs_client
->rpc_ops
->getroot(server
, mntfh
, &fsinfo
);
92 dprintk("nfs_get_root: getattr error = %d\n", -error
);
93 return ERR_PTR(error
);
96 inode
= nfs_fhget(sb
, mntfh
, fsinfo
.fattr
);
98 dprintk("nfs_get_root: get root inode failed\n");
99 return ERR_PTR(PTR_ERR(inode
));
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
106 mntroot
= d_alloc_anon(inode
);
109 dprintk("nfs_get_root: get root dentry failed\n");
110 return ERR_PTR(-ENOMEM
);
113 security_d_instantiate(mntroot
, inode
);
116 mntroot
->d_op
= server
->nfs_client
->rpc_ops
->dentry_ops
;
124 * Do a simple pathwalk from the root FH of the server to the nominated target
126 * - give error on symlinks
127 * - give error on ".." occurring in the path
128 * - follow traversals
130 int nfs4_path_walk(struct nfs_server
*server
,
131 struct nfs_fh
*mntfh
,
134 struct nfs_fsinfo fsinfo
;
135 struct nfs_fattr fattr
;
136 struct nfs_fh lastfh
;
139 //int referral_count = 0;
141 dprintk("--> nfs4_path_walk(,,%s)\n", path
);
143 fsinfo
.fattr
= &fattr
;
144 nfs_fattr_init(&fattr
);
146 if (*path
++ != '/') {
147 dprintk("nfs4_get_root: Path does not begin with a slash\n");
151 /* Start by getting the root filehandle from the server */
152 ret
= server
->nfs_client
->rpc_ops
->getroot(server
, mntfh
, &fsinfo
);
154 dprintk("nfs4_get_root: getroot error = %d\n", -ret
);
158 if (fattr
.type
!= NFDIR
) {
159 printk(KERN_ERR
"nfs4_get_root:"
160 " getroot encountered non-directory\n");
164 if (fattr
.valid
& NFS_ATTR_FATTR_V4_REFERRAL
) {
165 printk(KERN_ERR
"nfs4_get_root:"
166 " getroot obtained referral\n");
171 dprintk("Next: %s\n", path
);
173 /* extract the next bit of the path */
175 goto path_walk_complete
;
178 while (*path
&& *path
!= '/')
180 name
.len
= path
- (const char *) name
.name
;
186 if (path
[0] == '.' && (path
[1] == '/' || !path
[1])) {
191 if (path
[0] == '.' && path
[1] == '.' && (path
[2] == '/' || !path
[2])
193 printk(KERN_ERR
"nfs4_get_root:"
194 " Mount path contains reference to \"..\"\n");
198 /* lookup the next FH in the sequence */
199 memcpy(&lastfh
, mntfh
, sizeof(lastfh
));
201 dprintk("LookupFH: %*.*s [%s]\n", name
.len
, name
.len
, name
.name
, path
);
203 ret
= server
->nfs_client
->rpc_ops
->lookupfh(server
, &lastfh
, &name
,
206 dprintk("nfs4_get_root: getroot error = %d\n", -ret
);
210 if (fattr
.type
!= NFDIR
) {
211 printk(KERN_ERR
"nfs4_get_root:"
212 " lookupfh encountered non-directory\n");
216 if (fattr
.valid
& NFS_ATTR_FATTR_V4_REFERRAL
) {
217 printk(KERN_ERR
"nfs4_get_root:"
218 " lookupfh obtained referral\n");
225 memcpy(&server
->fsid
, &fattr
.fsid
, sizeof(server
->fsid
));
226 dprintk("<-- nfs4_path_walk() = 0\n");
231 * get an NFS4 root dentry from the root filehandle
233 struct dentry
*nfs4_get_root(struct super_block
*sb
, struct nfs_fh
*mntfh
)
235 struct nfs_server
*server
= NFS_SB(sb
);
236 struct nfs_fattr fattr
;
237 struct dentry
*mntroot
;
241 dprintk("--> nfs4_get_root()\n");
243 /* create a dummy root dentry with dummy inode for this superblock */
245 struct nfs_fh dummyfh
;
249 memset(&dummyfh
, 0, sizeof(dummyfh
));
250 memset(&fattr
, 0, sizeof(fattr
));
251 nfs_fattr_init(&fattr
);
252 fattr
.valid
= NFS_ATTR_FATTR
;
254 fattr
.mode
= S_IFDIR
| S_IRUSR
| S_IWUSR
;
257 iroot
= nfs_fhget(sb
, &dummyfh
, &fattr
);
259 return ERR_PTR(PTR_ERR(iroot
));
261 root
= d_alloc_root(iroot
);
264 return ERR_PTR(-ENOMEM
);
270 /* get the info about the server and filesystem */
271 error
= nfs4_server_capabilities(server
, mntfh
);
273 dprintk("nfs_get_root: getcaps error = %d\n",
275 return ERR_PTR(error
);
278 /* get the actual root for this mount */
279 error
= server
->nfs_client
->rpc_ops
->getattr(server
, mntfh
, &fattr
);
281 dprintk("nfs_get_root: getattr error = %d\n", -error
);
282 return ERR_PTR(error
);
285 inode
= nfs_fhget(sb
, mntfh
, &fattr
);
287 dprintk("nfs_get_root: get root inode failed\n");
288 return ERR_PTR(PTR_ERR(inode
));
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
295 mntroot
= d_alloc_anon(inode
);
298 dprintk("nfs_get_root: get root dentry failed\n");
299 return ERR_PTR(-ENOMEM
);
302 security_d_instantiate(mntroot
, inode
);
305 mntroot
->d_op
= server
->nfs_client
->rpc_ops
->dentry_ops
;
307 dprintk("<-- nfs4_get_root()\n");
311 #endif /* CONFIG_NFS_V4 */