blob: a70e446e1605fa43fb1b23b96418d8296773109f [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>
David Howells738a3512006-07-30 14:58:27 -040033#include <linux/security.h>
David Howells54ceac42006-08-22 20:06:13 -040034
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
David Howells54ceac42006-08-22 20:06:13 -040043
44/*
Trond Myklebustb09b9412007-10-25 13:56:10 -040045 * Set the superblock root dentry.
46 * Note that this function frees the inode in case of error.
47 */
48static 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 }
57 /* Circumvent igrab(): we know the inode is not being freed */
58 atomic_inc(&inode->i_count);
Trond Myklebusta10db502007-12-12 11:12:15 -050059 /*
60 * Ensure that this dentry is invisible to d_find_alias().
61 * Otherwise, it may be spliced into the tree by
62 * d_materialise_unique if a parent directory from the same
63 * filesystem gets mounted at a later time.
64 * This again causes shrink_dcache_for_umount_subtree() to
65 * Oops, since the test for IS_ROOT() will fail.
66 */
67 spin_lock(&dcache_lock);
68 list_del_init(&sb->s_root->d_alias);
69 spin_unlock(&dcache_lock);
Trond Myklebustb09b9412007-10-25 13:56:10 -040070 }
71 return 0;
72}
73
74/*
David Howells54ceac42006-08-22 20:06:13 -040075 * get an NFS2/NFS3 root dentry from the root filehandle
76 */
77struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
78{
79 struct nfs_server *server = NFS_SB(sb);
80 struct nfs_fsinfo fsinfo;
Trond Myklebust8bac9db2010-04-16 16:22:48 -040081 struct dentry *ret;
David Howells54ceac42006-08-22 20:06:13 -040082 struct inode *inode;
83 int error;
84
David Howells54ceac42006-08-22 20:06:13 -040085 /* get the actual root for this mount */
Trond Myklebust8bac9db2010-04-16 16:22:48 -040086 fsinfo.fattr = nfs_alloc_fattr();
87 if (fsinfo.fattr == NULL)
88 return ERR_PTR(-ENOMEM);
David Howells54ceac42006-08-22 20:06:13 -040089
90 error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
91 if (error < 0) {
92 dprintk("nfs_get_root: getattr error = %d\n", -error);
Trond Myklebust8bac9db2010-04-16 16:22:48 -040093 ret = ERR_PTR(error);
94 goto out;
David Howells54ceac42006-08-22 20:06:13 -040095 }
96
97 inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
98 if (IS_ERR(inode)) {
99 dprintk("nfs_get_root: get root inode failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400100 ret = ERR_CAST(inode);
101 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400102 }
103
Trond Myklebustb09b9412007-10-25 13:56:10 -0400104 error = nfs_superblock_set_dummy_root(sb, inode);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400105 if (error != 0) {
106 ret = ERR_PTR(error);
107 goto out;
108 }
Trond Myklebustb09b9412007-10-25 13:56:10 -0400109
David Howells54ceac42006-08-22 20:06:13 -0400110 /* root dentries normally start off anonymous and get spliced in later
111 * if the dentry tree reaches them; however if the dentry already
112 * exists, we'll pick it up at this point and use it as the root
113 */
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400114 ret = d_obtain_alias(inode);
115 if (IS_ERR(ret)) {
David Howells54ceac42006-08-22 20:06:13 -0400116 dprintk("nfs_get_root: get root dentry failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400117 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400118 }
119
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400120 security_d_instantiate(ret, inode);
David Howells738a3512006-07-30 14:58:27 -0400121
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400122 if (ret->d_op == NULL)
123 ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
124out:
125 nfs_free_fattr(fsinfo.fattr);
126 return ret;
David Howells54ceac42006-08-22 20:06:13 -0400127}
128
129#ifdef CONFIG_NFS_V4
130
Trond Myklebust815409d2010-04-16 16:22:46 -0400131int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh)
David Howells54ceac42006-08-22 20:06:13 -0400132{
133 struct nfs_fsinfo fsinfo;
Trond Myklebust815409d2010-04-16 16:22:46 -0400134 int ret = -ENOMEM;
David Howells54ceac42006-08-22 20:06:13 -0400135
Trond Myklebust815409d2010-04-16 16:22:46 -0400136 dprintk("--> nfs4_get_rootfh()\n");
David Howells54ceac42006-08-22 20:06:13 -0400137
Trond Myklebust815409d2010-04-16 16:22:46 -0400138 fsinfo.fattr = nfs_alloc_fattr();
139 if (fsinfo.fattr == NULL)
140 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400141
142 /* Start by getting the root filehandle from the server */
143 ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
144 if (ret < 0) {
Trond Myklebust815409d2010-04-16 16:22:46 -0400145 dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
146 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400147 }
148
Andy Adamsonf799bdb2010-06-16 09:51:02 -0400149 if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE)
Trond Myklebust815409d2010-04-16 16:22:46 -0400150 || !S_ISDIR(fsinfo.fattr->mode)) {
151 printk(KERN_ERR "nfs4_get_rootfh:"
David Howells54ceac42006-08-22 20:06:13 -0400152 " getroot encountered non-directory\n");
Trond Myklebust815409d2010-04-16 16:22:46 -0400153 ret = -ENOTDIR;
154 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400155 }
156
Trond Myklebust815409d2010-04-16 16:22:46 -0400157 if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
158 printk(KERN_ERR "nfs4_get_rootfh:"
David Howells54ceac42006-08-22 20:06:13 -0400159 " getroot obtained referral\n");
Trond Myklebust815409d2010-04-16 16:22:46 -0400160 ret = -EREMOTE;
161 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400162 }
163
Trond Myklebust815409d2010-04-16 16:22:46 -0400164 memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid));
165out:
166 nfs_free_fattr(fsinfo.fattr);
167 dprintk("<-- nfs4_get_rootfh() = %d\n", ret);
168 return ret;
David Howells54ceac42006-08-22 20:06:13 -0400169}
170
171/*
172 * get an NFS4 root dentry from the root filehandle
173 */
174struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
175{
176 struct nfs_server *server = NFS_SB(sb);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400177 struct nfs_fattr *fattr = NULL;
178 struct dentry *ret;
David Howells54ceac42006-08-22 20:06:13 -0400179 struct inode *inode;
180 int error;
181
182 dprintk("--> nfs4_get_root()\n");
183
David Howells54ceac42006-08-22 20:06:13 -0400184 /* get the info about the server and filesystem */
185 error = nfs4_server_capabilities(server, mntfh);
186 if (error < 0) {
187 dprintk("nfs_get_root: getcaps error = %d\n",
188 -error);
189 return ERR_PTR(error);
190 }
191
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400192 fattr = nfs_alloc_fattr();
193 if (fattr == NULL)
194 return ERR_PTR(-ENOMEM);;
195
David Howells54ceac42006-08-22 20:06:13 -0400196 /* get the actual root for this mount */
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400197 error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
David Howells54ceac42006-08-22 20:06:13 -0400198 if (error < 0) {
199 dprintk("nfs_get_root: getattr error = %d\n", -error);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400200 ret = ERR_PTR(error);
201 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400202 }
203
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400204 inode = nfs_fhget(sb, mntfh, fattr);
David Howells54ceac42006-08-22 20:06:13 -0400205 if (IS_ERR(inode)) {
206 dprintk("nfs_get_root: get root inode failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400207 ret = ERR_CAST(inode);
208 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400209 }
210
Trond Myklebustb09b9412007-10-25 13:56:10 -0400211 error = nfs_superblock_set_dummy_root(sb, inode);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400212 if (error != 0) {
213 ret = ERR_PTR(error);
214 goto out;
215 }
Trond Myklebustb09b9412007-10-25 13:56:10 -0400216
David Howells54ceac42006-08-22 20:06:13 -0400217 /* root dentries normally start off anonymous and get spliced in later
218 * if the dentry tree reaches them; however if the dentry already
219 * exists, we'll pick it up at this point and use it as the root
220 */
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400221 ret = d_obtain_alias(inode);
222 if (IS_ERR(ret)) {
David Howells54ceac42006-08-22 20:06:13 -0400223 dprintk("nfs_get_root: get root dentry failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400224 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400225 }
226
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400227 security_d_instantiate(ret, inode);
David Howells738a3512006-07-30 14:58:27 -0400228
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400229 if (ret->d_op == NULL)
230 ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
David Howells54ceac42006-08-22 20:06:13 -0400231
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400232out:
233 nfs_free_fattr(fattr);
David Howells54ceac42006-08-22 20:06:13 -0400234 dprintk("<-- nfs4_get_root()\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400235 return ret;
David Howells54ceac42006-08-22 20:06:13 -0400236}
237
238#endif /* CONFIG_NFS_V4 */