1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
|
/* getroot.c: get the root dentry for an NFS mount
*
* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/stats.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/lockd/bind.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/nfs_idmap.h>
#include <linux/vfs.h>
#include <linux/namei.h>
#include <linux/security.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include "nfs4_fs.h"
#include "delegation.h"
#include "internal.h"
#define NFSDBG_FACILITY NFSDBG_CLIENT
/*
* Set the superblock root dentry.
* Note that this function frees the inode in case of error.
*/
static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
{
/* The mntroot acts as the dummy root dentry for this superblock */
if (sb->s_root == NULL) {
sb->s_root = d_alloc_root(inode);
if (sb->s_root == NULL) {
iput(inode);
return -ENOMEM;
}
ihold(inode);
/*
* Ensure that this dentry is invisible to d_find_alias().
* Otherwise, it may be spliced into the tree by
* d_materialise_unique if a parent directory from the same
* filesystem gets mounted at a later time.
* This again causes shrink_dcache_for_umount_subtree() to
* Oops, since the test for IS_ROOT() will fail.
*/
spin_lock(&dcache_inode_lock);
spin_lock(&sb->s_root->d_lock);
list_del_init(&sb->s_root->d_alias);
spin_unlock(&sb->s_root->d_lock);
spin_unlock(&dcache_inode_lock);
}
return 0;
}
/*
* get an NFS2/NFS3 root dentry from the root filehandle
*/
struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
{
struct nfs_server *server = NFS_SB(sb);
struct nfs_fsinfo fsinfo;
struct dentry *ret;
struct inode *inode;
int error;
/* get the actual root for this mount */
fsinfo.fattr = nfs_alloc_fattr();
if (fsinfo.fattr == NULL)
return ERR_PTR(-ENOMEM);
error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
if (error < 0) {
dprintk("nfs_get_root: getattr error = %d\n", -error);
ret = ERR_PTR(error);
goto out;
}
inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
if (IS_ERR(inode)) {
dprintk("nfs_get_root: get root inode failed\n");
ret = ERR_CAST(inode);
goto out;
}
error = nfs_superblock_set_dummy_root(sb, inode);
if (error != 0) {
ret = ERR_PTR(error);
goto out;
}
/* root dentries normally start off anonymous and get spliced in later
* if the dentry tree reaches them; however if the dentry already
* exists, we'll pick it up at this point and use it as the root
*/
ret = d_obtain_alias(inode);
if (IS_ERR(ret)) {
dprintk("nfs_get_root: get root dentry failed\n");
goto out;
}
security_d_instantiate(ret, inode);
if (ret->d_op == NULL)
ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
out:
nfs_free_fattr(fsinfo.fattr);
return ret;
}
#ifdef CONFIG_NFS_V4
int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh)
{
struct nfs_fsinfo fsinfo;
int ret = -ENOMEM;
dprintk("--> nfs4_get_rootfh()\n");
fsinfo.fattr = nfs_alloc_fattr();
if (fsinfo.fattr == NULL)
goto out;
/* Start by getting the root filehandle from the server */
ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
if (ret < 0) {
dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
goto out;
}
if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE)
|| !S_ISDIR(fsinfo.fattr->mode)) {
printk(KERN_ERR "nfs4_get_rootfh:"
" getroot encountered non-directory\n");
ret = -ENOTDIR;
goto out;
}
if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
printk(KERN_ERR "nfs4_get_rootfh:"
" getroot obtained referral\n");
ret = -EREMOTE;
goto out;
}
memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid));
out:
nfs_free_fattr(fsinfo.fattr);
dprintk("<-- nfs4_get_rootfh() = %d\n", ret);
return ret;
}
/*
* get an NFS4 root dentry from the root filehandle
*/
struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
{
struct nfs_server *server = NFS_SB(sb);
struct nfs_fattr *fattr = NULL;
struct dentry *ret;
struct inode *inode;
int error;
dprintk("--> nfs4_get_root()\n");
/* get the info about the server and filesystem */
error = nfs4_server_capabilities(server, mntfh);
if (error < 0) {
dprintk("nfs_get_root: getcaps error = %d\n",
-error);
return ERR_PTR(error);
}
fattr = nfs_alloc_fattr();
if (fattr == NULL)
return ERR_PTR(-ENOMEM);;
/* get the actual root for this mount */
error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
if (error < 0) {
dprintk("nfs_get_root: getattr error = %d\n", -error);
ret = ERR_PTR(error);
goto out;
}
inode = nfs_fhget(sb, mntfh, fattr);
if (IS_ERR(inode)) {
dprintk("nfs_get_root: get root inode failed\n");
ret = ERR_CAST(inode);
goto out;
}
error = nfs_superblock_set_dummy_root(sb, inode);
if (error != 0) {
ret = ERR_PTR(error);
goto out;
}
/* root dentries normally start off anonymous and get spliced in later
* if the dentry tree reaches them; however if the dentry already
* exists, we'll pick it up at this point and use it as the root
*/
ret = d_obtain_alias(inode);
if (IS_ERR(ret)) {
dprintk("nfs_get_root: get root dentry failed\n");
goto out;
}
security_d_instantiate(ret, inode);
if (ret->d_op == NULL)
ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
out:
nfs_free_fattr(fattr);
dprintk("<-- nfs4_get_root()\n");
return ret;
}
#endif /* CONFIG_NFS_V4 */
|
