Commit | Line | Data |
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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 | 34 | |
54ceac45 DH |
35 | #include <asm/uaccess.h> |
36 | ||
37 | #include "nfs4_fs.h" | |
38 | #include "delegation.h" | |
39 | #include "internal.h" | |
40 | ||
41 | #define NFSDBG_FACILITY NFSDBG_CLIENT | |
54ceac45 | 42 | |
b09b9417 TM |
43 | /* |
44 | * Set the superblock root dentry. | |
45 | * Note that this function frees the inode in case of error. | |
46 | */ | |
47 | static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode) | |
48 | { | |
49 | /* The mntroot acts as the dummy root dentry for this superblock */ | |
50 | if (sb->s_root == NULL) { | |
48fde701 AV |
51 | sb->s_root = d_make_root(inode); |
52 | if (sb->s_root == NULL) | |
b09b9417 | 53 | return -ENOMEM; |
7de9c6ee | 54 | ihold(inode); |
a10db50a TM |
55 | /* |
56 | * Ensure that this dentry is invisible to d_find_alias(). | |
57 | * Otherwise, it may be spliced into the tree by | |
58 | * d_materialise_unique if a parent directory from the same | |
59 | * filesystem gets mounted at a later time. | |
60 | * This again causes shrink_dcache_for_umount_subtree() to | |
61 | * Oops, since the test for IS_ROOT() will fail. | |
62 | */ | |
873feea0 | 63 | spin_lock(&sb->s_root->d_inode->i_lock); |
b23fb0a6 | 64 | spin_lock(&sb->s_root->d_lock); |
a10db50a | 65 | list_del_init(&sb->s_root->d_alias); |
b23fb0a6 | 66 | spin_unlock(&sb->s_root->d_lock); |
873feea0 | 67 | spin_unlock(&sb->s_root->d_inode->i_lock); |
b09b9417 TM |
68 | } |
69 | return 0; | |
70 | } | |
71 | ||
54ceac45 DH |
72 | /* |
73 | * get an NFS2/NFS3 root dentry from the root filehandle | |
74 | */ | |
0d5839ad AV |
75 | struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh, |
76 | const char *devname) | |
54ceac45 DH |
77 | { |
78 | struct nfs_server *server = NFS_SB(sb); | |
79 | struct nfs_fsinfo fsinfo; | |
8bac9db9 | 80 | struct dentry *ret; |
54ceac45 | 81 | struct inode *inode; |
b1942c5f | 82 | void *name = kstrdup(devname, GFP_KERNEL); |
54ceac45 DH |
83 | int error; |
84 | ||
b1942c5f AV |
85 | if (!name) |
86 | return ERR_PTR(-ENOMEM); | |
87 | ||
54ceac45 | 88 | /* get the actual root for this mount */ |
8bac9db9 | 89 | fsinfo.fattr = nfs_alloc_fattr(); |
b1942c5f AV |
90 | if (fsinfo.fattr == NULL) { |
91 | kfree(name); | |
8bac9db9 | 92 | return ERR_PTR(-ENOMEM); |
b1942c5f | 93 | } |
54ceac45 DH |
94 | |
95 | error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); | |
96 | if (error < 0) { | |
97 | dprintk("nfs_get_root: getattr error = %d\n", -error); | |
8bac9db9 TM |
98 | ret = ERR_PTR(error); |
99 | goto out; | |
54ceac45 DH |
100 | } |
101 | ||
102 | inode = nfs_fhget(sb, mntfh, fsinfo.fattr); | |
103 | if (IS_ERR(inode)) { | |
104 | dprintk("nfs_get_root: get root inode failed\n"); | |
8bac9db9 TM |
105 | ret = ERR_CAST(inode); |
106 | goto out; | |
54ceac45 DH |
107 | } |
108 | ||
b09b9417 | 109 | error = nfs_superblock_set_dummy_root(sb, inode); |
8bac9db9 TM |
110 | if (error != 0) { |
111 | ret = ERR_PTR(error); | |
112 | goto out; | |
113 | } | |
b09b9417 | 114 | |
54ceac45 DH |
115 | /* root dentries normally start off anonymous and get spliced in later |
116 | * if the dentry tree reaches them; however if the dentry already | |
117 | * exists, we'll pick it up at this point and use it as the root | |
118 | */ | |
8bac9db9 TM |
119 | ret = d_obtain_alias(inode); |
120 | if (IS_ERR(ret)) { | |
54ceac45 | 121 | dprintk("nfs_get_root: get root dentry failed\n"); |
8bac9db9 | 122 | goto out; |
54ceac45 DH |
123 | } |
124 | ||
8bac9db9 | 125 | security_d_instantiate(ret, inode); |
b1942c5f AV |
126 | spin_lock(&ret->d_lock); |
127 | if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) { | |
128 | ret->d_fsdata = name; | |
129 | name = NULL; | |
130 | } | |
131 | spin_unlock(&ret->d_lock); | |
8bac9db9 | 132 | out: |
b1942c5f AV |
133 | if (name) |
134 | kfree(name); | |
8bac9db9 TM |
135 | nfs_free_fattr(fsinfo.fattr); |
136 | return ret; | |
54ceac45 DH |
137 | } |
138 | ||
139 | #ifdef CONFIG_NFS_V4 | |
140 | ||
815409d2 | 141 | int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh) |
54ceac45 DH |
142 | { |
143 | struct nfs_fsinfo fsinfo; | |
815409d2 | 144 | int ret = -ENOMEM; |
54ceac45 | 145 | |
815409d2 | 146 | dprintk("--> nfs4_get_rootfh()\n"); |
54ceac45 | 147 | |
815409d2 TM |
148 | fsinfo.fattr = nfs_alloc_fattr(); |
149 | if (fsinfo.fattr == NULL) | |
150 | goto out; | |
54ceac45 DH |
151 | |
152 | /* Start by getting the root filehandle from the server */ | |
3028eb2b | 153 | ret = nfs4_proc_get_rootfh(server, mntfh, &fsinfo); |
54ceac45 | 154 | if (ret < 0) { |
815409d2 TM |
155 | dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret); |
156 | goto out; | |
54ceac45 DH |
157 | } |
158 | ||
f799bdb3 | 159 | if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE) |
815409d2 TM |
160 | || !S_ISDIR(fsinfo.fattr->mode)) { |
161 | printk(KERN_ERR "nfs4_get_rootfh:" | |
54ceac45 | 162 | " getroot encountered non-directory\n"); |
815409d2 TM |
163 | ret = -ENOTDIR; |
164 | goto out; | |
54ceac45 DH |
165 | } |
166 | ||
815409d2 TM |
167 | if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) { |
168 | printk(KERN_ERR "nfs4_get_rootfh:" | |
54ceac45 | 169 | " getroot obtained referral\n"); |
815409d2 TM |
170 | ret = -EREMOTE; |
171 | goto out; | |
54ceac45 DH |
172 | } |
173 | ||
815409d2 TM |
174 | memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid)); |
175 | out: | |
176 | nfs_free_fattr(fsinfo.fattr); | |
177 | dprintk("<-- nfs4_get_rootfh() = %d\n", ret); | |
178 | return ret; | |
54ceac45 DH |
179 | } |
180 | ||
54ceac45 | 181 | #endif /* CONFIG_NFS_V4 */ |