blob: dcb61548887fdba13fc484c844aeb3a6b14a0fe9 [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 }
Al Viro7de9c6e2010-10-23 11:11:40 -040057 ihold(inode);
Trond Myklebusta10db502007-12-12 11:12:15 -050058 /*
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 */
Nick Piggin873feea2011-01-07 17:50:06 +110066 spin_lock(&sb->s_root->d_inode->i_lock);
Nick Pigginb23fb0a2011-01-07 17:49:35 +110067 spin_lock(&sb->s_root->d_lock);
Trond Myklebusta10db502007-12-12 11:12:15 -050068 list_del_init(&sb->s_root->d_alias);
Nick Pigginb23fb0a2011-01-07 17:49:35 +110069 spin_unlock(&sb->s_root->d_lock);
Nick Piggin873feea2011-01-07 17:50:06 +110070 spin_unlock(&sb->s_root->d_inode->i_lock);
Trond Myklebustb09b9412007-10-25 13:56:10 -040071 }
72 return 0;
73}
74
75/*
David Howells54ceac42006-08-22 20:06:13 -040076 * get an NFS2/NFS3 root dentry from the root filehandle
77 */
Al Viro0d5839a2011-03-16 05:27:27 -040078struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
79 const char *devname)
David Howells54ceac42006-08-22 20:06:13 -040080{
81 struct nfs_server *server = NFS_SB(sb);
82 struct nfs_fsinfo fsinfo;
Trond Myklebust8bac9db2010-04-16 16:22:48 -040083 struct dentry *ret;
David Howells54ceac42006-08-22 20:06:13 -040084 struct inode *inode;
Al Virob1942c52011-03-16 05:44:14 -040085 void *name = kstrdup(devname, GFP_KERNEL);
David Howells54ceac42006-08-22 20:06:13 -040086 int error;
87
Al Virob1942c52011-03-16 05:44:14 -040088 if (!name)
89 return ERR_PTR(-ENOMEM);
90
David Howells54ceac42006-08-22 20:06:13 -040091 /* get the actual root for this mount */
Trond Myklebust8bac9db2010-04-16 16:22:48 -040092 fsinfo.fattr = nfs_alloc_fattr();
Al Virob1942c52011-03-16 05:44:14 -040093 if (fsinfo.fattr == NULL) {
94 kfree(name);
Trond Myklebust8bac9db2010-04-16 16:22:48 -040095 return ERR_PTR(-ENOMEM);
Al Virob1942c52011-03-16 05:44:14 -040096 }
David Howells54ceac42006-08-22 20:06:13 -040097
98 error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
99 if (error < 0) {
100 dprintk("nfs_get_root: getattr error = %d\n", -error);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400101 ret = ERR_PTR(error);
102 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400103 }
104
105 inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
106 if (IS_ERR(inode)) {
107 dprintk("nfs_get_root: get root inode failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400108 ret = ERR_CAST(inode);
109 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400110 }
111
Trond Myklebustb09b9412007-10-25 13:56:10 -0400112 error = nfs_superblock_set_dummy_root(sb, inode);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400113 if (error != 0) {
114 ret = ERR_PTR(error);
115 goto out;
116 }
Trond Myklebustb09b9412007-10-25 13:56:10 -0400117
David Howells54ceac42006-08-22 20:06:13 -0400118 /* root dentries normally start off anonymous and get spliced in later
119 * if the dentry tree reaches them; however if the dentry already
120 * exists, we'll pick it up at this point and use it as the root
121 */
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400122 ret = d_obtain_alias(inode);
123 if (IS_ERR(ret)) {
David Howells54ceac42006-08-22 20:06:13 -0400124 dprintk("nfs_get_root: get root dentry failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400125 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400126 }
127
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400128 security_d_instantiate(ret, inode);
Al Virob1942c52011-03-16 05:44:14 -0400129 spin_lock(&ret->d_lock);
130 if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
131 ret->d_fsdata = name;
132 name = NULL;
133 }
134 spin_unlock(&ret->d_lock);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400135out:
Al Virob1942c52011-03-16 05:44:14 -0400136 if (name)
137 kfree(name);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400138 nfs_free_fattr(fsinfo.fattr);
139 return ret;
David Howells54ceac42006-08-22 20:06:13 -0400140}
141
142#ifdef CONFIG_NFS_V4
143
Trond Myklebust815409d2010-04-16 16:22:46 -0400144int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh)
David Howells54ceac42006-08-22 20:06:13 -0400145{
146 struct nfs_fsinfo fsinfo;
Trond Myklebust815409d2010-04-16 16:22:46 -0400147 int ret = -ENOMEM;
David Howells54ceac42006-08-22 20:06:13 -0400148
Trond Myklebust815409d2010-04-16 16:22:46 -0400149 dprintk("--> nfs4_get_rootfh()\n");
David Howells54ceac42006-08-22 20:06:13 -0400150
Trond Myklebust815409d2010-04-16 16:22:46 -0400151 fsinfo.fattr = nfs_alloc_fattr();
152 if (fsinfo.fattr == NULL)
153 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400154
155 /* Start by getting the root filehandle from the server */
156 ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
157 if (ret < 0) {
Trond Myklebust815409d2010-04-16 16:22:46 -0400158 dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
159 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400160 }
161
Andy Adamsonf799bdb2010-06-16 09:51:02 -0400162 if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE)
Trond Myklebust815409d2010-04-16 16:22:46 -0400163 || !S_ISDIR(fsinfo.fattr->mode)) {
164 printk(KERN_ERR "nfs4_get_rootfh:"
David Howells54ceac42006-08-22 20:06:13 -0400165 " getroot encountered non-directory\n");
Trond Myklebust815409d2010-04-16 16:22:46 -0400166 ret = -ENOTDIR;
167 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400168 }
169
Trond Myklebust815409d2010-04-16 16:22:46 -0400170 if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
171 printk(KERN_ERR "nfs4_get_rootfh:"
David Howells54ceac42006-08-22 20:06:13 -0400172 " getroot obtained referral\n");
Trond Myklebust815409d2010-04-16 16:22:46 -0400173 ret = -EREMOTE;
174 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400175 }
176
Trond Myklebust815409d2010-04-16 16:22:46 -0400177 memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid));
178out:
179 nfs_free_fattr(fsinfo.fattr);
180 dprintk("<-- nfs4_get_rootfh() = %d\n", ret);
181 return ret;
David Howells54ceac42006-08-22 20:06:13 -0400182}
183
184/*
185 * get an NFS4 root dentry from the root filehandle
186 */
Al Viro0d5839a2011-03-16 05:27:27 -0400187struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh,
188 const char *devname)
David Howells54ceac42006-08-22 20:06:13 -0400189{
190 struct nfs_server *server = NFS_SB(sb);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400191 struct nfs_fattr *fattr = NULL;
192 struct dentry *ret;
David Howells54ceac42006-08-22 20:06:13 -0400193 struct inode *inode;
Al Virob1942c52011-03-16 05:44:14 -0400194 void *name = kstrdup(devname, GFP_KERNEL);
David Howells54ceac42006-08-22 20:06:13 -0400195 int error;
196
197 dprintk("--> nfs4_get_root()\n");
198
Al Virob1942c52011-03-16 05:44:14 -0400199 if (!name)
200 return ERR_PTR(-ENOMEM);
201
David Howells54ceac42006-08-22 20:06:13 -0400202 /* get the info about the server and filesystem */
203 error = nfs4_server_capabilities(server, mntfh);
204 if (error < 0) {
205 dprintk("nfs_get_root: getcaps error = %d\n",
206 -error);
Al Virob1942c52011-03-16 05:44:14 -0400207 kfree(name);
David Howells54ceac42006-08-22 20:06:13 -0400208 return ERR_PTR(error);
209 }
210
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400211 fattr = nfs_alloc_fattr();
Al Virob1942c52011-03-16 05:44:14 -0400212 if (fattr == NULL) {
213 kfree(name);
214 return ERR_PTR(-ENOMEM);
215 }
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400216
David Howells54ceac42006-08-22 20:06:13 -0400217 /* get the actual root for this mount */
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400218 error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
David Howells54ceac42006-08-22 20:06:13 -0400219 if (error < 0) {
220 dprintk("nfs_get_root: getattr error = %d\n", -error);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400221 ret = ERR_PTR(error);
222 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400223 }
224
Gusev Vitaliy46670582011-03-23 00:40:25 +0300225 if (fattr->valid & NFS_ATTR_FATTR_FSID &&
226 !nfs_fsid_equal(&server->fsid, &fattr->fsid))
227 memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
228
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400229 inode = nfs_fhget(sb, mntfh, fattr);
David Howells54ceac42006-08-22 20:06:13 -0400230 if (IS_ERR(inode)) {
231 dprintk("nfs_get_root: get root inode failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400232 ret = ERR_CAST(inode);
233 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400234 }
235
Trond Myklebustb09b9412007-10-25 13:56:10 -0400236 error = nfs_superblock_set_dummy_root(sb, inode);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400237 if (error != 0) {
238 ret = ERR_PTR(error);
239 goto out;
240 }
Trond Myklebustb09b9412007-10-25 13:56:10 -0400241
David Howells54ceac42006-08-22 20:06:13 -0400242 /* root dentries normally start off anonymous and get spliced in later
243 * if the dentry tree reaches them; however if the dentry already
244 * exists, we'll pick it up at this point and use it as the root
245 */
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400246 ret = d_obtain_alias(inode);
247 if (IS_ERR(ret)) {
David Howells54ceac42006-08-22 20:06:13 -0400248 dprintk("nfs_get_root: get root dentry failed\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400249 goto out;
David Howells54ceac42006-08-22 20:06:13 -0400250 }
251
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400252 security_d_instantiate(ret, inode);
Al Virob1942c52011-03-16 05:44:14 -0400253 spin_lock(&ret->d_lock);
254 if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
255 ret->d_fsdata = name;
256 name = NULL;
257 }
258 spin_unlock(&ret->d_lock);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400259out:
Al Virob1942c52011-03-16 05:44:14 -0400260 if (name)
261 kfree(name);
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400262 nfs_free_fattr(fattr);
David Howells54ceac42006-08-22 20:06:13 -0400263 dprintk("<-- nfs4_get_root()\n");
Trond Myklebust8bac9db2010-04-16 16:22:48 -0400264 return ret;
David Howells54ceac42006-08-22 20:06:13 -0400265}
266
267#endif /* CONFIG_NFS_V4 */