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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> | |
738a3519 | 33 | #include <linux/security.h> |
54ceac45 DH |
34 | |
35 | #include <asm/system.h> | |
36 | #include <asm/uaccess.h> | |
37 | ||
38 | #include "nfs4_fs.h" | |
39 | #include "delegation.h" | |
40 | #include "internal.h" | |
41 | ||
42 | #define NFSDBG_FACILITY NFSDBG_CLIENT | |
54ceac45 | 43 | |
b09b9417 TM |
44 | /* |
45 | * Set the superblock root dentry. | |
46 | * Note that this function frees the inode in case of error. | |
47 | */ | |
48 | static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode) | |
49 | { | |
50 | /* The mntroot acts as the dummy root dentry for this superblock */ | |
51 | if (sb->s_root == NULL) { | |
52 | sb->s_root = d_alloc_root(inode); | |
53 | if (sb->s_root == NULL) { | |
54 | iput(inode); | |
55 | return -ENOMEM; | |
56 | } | |
7de9c6ee | 57 | ihold(inode); |
a10db50a TM |
58 | /* |
59 | * Ensure that this dentry is invisible to d_find_alias(). | |
60 | * Otherwise, it may be spliced into the tree by | |
61 | * d_materialise_unique if a parent directory from the same | |
62 | * filesystem gets mounted at a later time. | |
63 | * This again causes shrink_dcache_for_umount_subtree() to | |
64 | * Oops, since the test for IS_ROOT() will fail. | |
65 | */ | |
66 | spin_lock(&dcache_lock); | |
67 | list_del_init(&sb->s_root->d_alias); | |
68 | spin_unlock(&dcache_lock); | |
b09b9417 TM |
69 | } |
70 | return 0; | |
71 | } | |
72 | ||
54ceac45 DH |
73 | /* |
74 | * get an NFS2/NFS3 root dentry from the root filehandle | |
75 | */ | |
76 | struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
77 | { | |
78 | struct nfs_server *server = NFS_SB(sb); | |
79 | struct nfs_fsinfo fsinfo; | |
8bac9db9 | 80 | struct dentry *ret; |
54ceac45 DH |
81 | struct inode *inode; |
82 | int error; | |
83 | ||
54ceac45 | 84 | /* get the actual root for this mount */ |
8bac9db9 TM |
85 | fsinfo.fattr = nfs_alloc_fattr(); |
86 | if (fsinfo.fattr == NULL) | |
87 | return ERR_PTR(-ENOMEM); | |
54ceac45 DH |
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); | |
8bac9db9 TM |
92 | ret = ERR_PTR(error); |
93 | goto out; | |
54ceac45 DH |
94 | } |
95 | ||
96 | inode = nfs_fhget(sb, mntfh, fsinfo.fattr); | |
97 | if (IS_ERR(inode)) { | |
98 | dprintk("nfs_get_root: get root inode failed\n"); | |
8bac9db9 TM |
99 | ret = ERR_CAST(inode); |
100 | goto out; | |
54ceac45 DH |
101 | } |
102 | ||
b09b9417 | 103 | error = nfs_superblock_set_dummy_root(sb, inode); |
8bac9db9 TM |
104 | if (error != 0) { |
105 | ret = ERR_PTR(error); | |
106 | goto out; | |
107 | } | |
b09b9417 | 108 | |
54ceac45 DH |
109 | /* root dentries normally start off anonymous and get spliced in later |
110 | * if the dentry tree reaches them; however if the dentry already | |
111 | * exists, we'll pick it up at this point and use it as the root | |
112 | */ | |
8bac9db9 TM |
113 | ret = d_obtain_alias(inode); |
114 | if (IS_ERR(ret)) { | |
54ceac45 | 115 | dprintk("nfs_get_root: get root dentry failed\n"); |
8bac9db9 | 116 | goto out; |
54ceac45 DH |
117 | } |
118 | ||
8bac9db9 | 119 | security_d_instantiate(ret, inode); |
738a3519 | 120 | |
8bac9db9 TM |
121 | if (ret->d_op == NULL) |
122 | ret->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
123 | out: | |
124 | nfs_free_fattr(fsinfo.fattr); | |
125 | return ret; | |
54ceac45 DH |
126 | } |
127 | ||
128 | #ifdef CONFIG_NFS_V4 | |
129 | ||
815409d2 | 130 | int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh) |
54ceac45 DH |
131 | { |
132 | struct nfs_fsinfo fsinfo; | |
815409d2 | 133 | int ret = -ENOMEM; |
54ceac45 | 134 | |
815409d2 | 135 | dprintk("--> nfs4_get_rootfh()\n"); |
54ceac45 | 136 | |
815409d2 TM |
137 | fsinfo.fattr = nfs_alloc_fattr(); |
138 | if (fsinfo.fattr == NULL) | |
139 | goto out; | |
54ceac45 DH |
140 | |
141 | /* Start by getting the root filehandle from the server */ | |
142 | ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
143 | if (ret < 0) { | |
815409d2 TM |
144 | dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret); |
145 | goto out; | |
54ceac45 DH |
146 | } |
147 | ||
f799bdb3 | 148 | if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE) |
815409d2 TM |
149 | || !S_ISDIR(fsinfo.fattr->mode)) { |
150 | printk(KERN_ERR "nfs4_get_rootfh:" | |
54ceac45 | 151 | " getroot encountered non-directory\n"); |
815409d2 TM |
152 | ret = -ENOTDIR; |
153 | goto out; | |
54ceac45 DH |
154 | } |
155 | ||
815409d2 TM |
156 | if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) { |
157 | printk(KERN_ERR "nfs4_get_rootfh:" | |
54ceac45 | 158 | " getroot obtained referral\n"); |
815409d2 TM |
159 | ret = -EREMOTE; |
160 | goto out; | |
54ceac45 DH |
161 | } |
162 | ||
815409d2 TM |
163 | memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid)); |
164 | out: | |
165 | nfs_free_fattr(fsinfo.fattr); | |
166 | dprintk("<-- nfs4_get_rootfh() = %d\n", ret); | |
167 | return ret; | |
54ceac45 DH |
168 | } |
169 | ||
170 | /* | |
171 | * get an NFS4 root dentry from the root filehandle | |
172 | */ | |
173 | struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) | |
174 | { | |
175 | struct nfs_server *server = NFS_SB(sb); | |
8bac9db9 TM |
176 | struct nfs_fattr *fattr = NULL; |
177 | struct dentry *ret; | |
54ceac45 DH |
178 | struct inode *inode; |
179 | int error; | |
180 | ||
181 | dprintk("--> nfs4_get_root()\n"); | |
182 | ||
54ceac45 DH |
183 | /* get the info about the server and filesystem */ |
184 | error = nfs4_server_capabilities(server, mntfh); | |
185 | if (error < 0) { | |
186 | dprintk("nfs_get_root: getcaps error = %d\n", | |
187 | -error); | |
188 | return ERR_PTR(error); | |
189 | } | |
190 | ||
8bac9db9 TM |
191 | fattr = nfs_alloc_fattr(); |
192 | if (fattr == NULL) | |
193 | return ERR_PTR(-ENOMEM);; | |
194 | ||
54ceac45 | 195 | /* get the actual root for this mount */ |
8bac9db9 | 196 | error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr); |
54ceac45 DH |
197 | if (error < 0) { |
198 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
8bac9db9 TM |
199 | ret = ERR_PTR(error); |
200 | goto out; | |
54ceac45 DH |
201 | } |
202 | ||
8bac9db9 | 203 | inode = nfs_fhget(sb, mntfh, fattr); |
54ceac45 DH |
204 | if (IS_ERR(inode)) { |
205 | dprintk("nfs_get_root: get root inode failed\n"); | |
8bac9db9 TM |
206 | ret = ERR_CAST(inode); |
207 | goto out; | |
54ceac45 DH |
208 | } |
209 | ||
b09b9417 | 210 | error = nfs_superblock_set_dummy_root(sb, inode); |
8bac9db9 TM |
211 | if (error != 0) { |
212 | ret = ERR_PTR(error); | |
213 | goto out; | |
214 | } | |
b09b9417 | 215 | |
54ceac45 DH |
216 | /* root dentries normally start off anonymous and get spliced in later |
217 | * if the dentry tree reaches them; however if the dentry already | |
218 | * exists, we'll pick it up at this point and use it as the root | |
219 | */ | |
8bac9db9 TM |
220 | ret = d_obtain_alias(inode); |
221 | if (IS_ERR(ret)) { | |
54ceac45 | 222 | dprintk("nfs_get_root: get root dentry failed\n"); |
8bac9db9 | 223 | goto out; |
54ceac45 DH |
224 | } |
225 | ||
8bac9db9 | 226 | security_d_instantiate(ret, inode); |
738a3519 | 227 | |
8bac9db9 TM |
228 | if (ret->d_op == NULL) |
229 | ret->d_op = server->nfs_client->rpc_ops->dentry_ops; | |
54ceac45 | 230 | |
8bac9db9 TM |
231 | out: |
232 | nfs_free_fattr(fattr); | |
54ceac45 | 233 | dprintk("<-- nfs4_get_root()\n"); |
8bac9db9 | 234 | return ret; |
54ceac45 DH |
235 | } |
236 | ||
237 | #endif /* CONFIG_NFS_V4 */ |