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 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> 28 #include <linux/smp_lock.h> 29 #include <linux/seq_file.h> 30 #include <linux/mount.h> 31 #include <linux/nfs_idmap.h> 32 #include <linux/vfs.h> 33 #include <linux/namei.h> 34 #include <linux/mnt_namespace.h> 35 #include <linux/security.h> 36 37 #include <asm/system.h> 38 #include <asm/uaccess.h> 39 40 #include "nfs4_fs.h" 41 #include "delegation.h" 42 #include "internal.h" 43 44 #define NFSDBG_FACILITY NFSDBG_CLIENT 45 #define NFS_PARANOIA 1 46 47 /* 48 * get an NFS2/NFS3 root dentry from the root filehandle 49 */ 50 struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh) 51 { 52 struct nfs_server *server = NFS_SB(sb); 53 struct nfs_fsinfo fsinfo; 54 struct nfs_fattr fattr; 55 struct dentry *mntroot; 56 struct inode *inode; 57 int error; 58 59 /* create a dummy root dentry with dummy inode for this superblock */ 60 if (!sb->s_root) { 61 struct nfs_fh dummyfh; 62 struct dentry *root; 63 struct inode *iroot; 64 65 memset(&dummyfh, 0, sizeof(dummyfh)); 66 memset(&fattr, 0, sizeof(fattr)); 67 nfs_fattr_init(&fattr); 68 fattr.valid = NFS_ATTR_FATTR; 69 fattr.type = NFDIR; 70 fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; 71 fattr.nlink = 2; 72 73 iroot = nfs_fhget(sb, &dummyfh, &fattr); 74 if (IS_ERR(iroot)) 75 return ERR_PTR(PTR_ERR(iroot)); 76 77 root = d_alloc_root(iroot); 78 if (!root) { 79 iput(iroot); 80 return ERR_PTR(-ENOMEM); 81 } 82 83 sb->s_root = root; 84 } 85 86 /* get the actual root for this mount */ 87 fsinfo.fattr = &fattr; 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); 92 return ERR_PTR(error); 93 } 94 95 inode = nfs_fhget(sb, mntfh, fsinfo.fattr); 96 if (IS_ERR(inode)) { 97 dprintk("nfs_get_root: get root inode failed\n"); 98 return ERR_PTR(PTR_ERR(inode)); 99 } 100 101 /* root dentries normally start off anonymous and get spliced in later 102 * if the dentry tree reaches them; however if the dentry already 103 * exists, we'll pick it up at this point and use it as the root 104 */ 105 mntroot = d_alloc_anon(inode); 106 if (!mntroot) { 107 iput(inode); 108 dprintk("nfs_get_root: get root dentry failed\n"); 109 return ERR_PTR(-ENOMEM); 110 } 111 112 security_d_instantiate(mntroot, inode); 113 114 if (!mntroot->d_op) 115 mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; 116 117 return mntroot; 118 } 119 120 #ifdef CONFIG_NFS_V4 121 122 /* 123 * Do a simple pathwalk from the root FH of the server to the nominated target 124 * of the mountpoint 125 * - give error on symlinks 126 * - give error on ".." occurring in the path 127 * - follow traversals 128 */ 129 int nfs4_path_walk(struct nfs_server *server, 130 struct nfs_fh *mntfh, 131 const char *path) 132 { 133 struct nfs_fsinfo fsinfo; 134 struct nfs_fattr fattr; 135 struct nfs_fh lastfh; 136 struct qstr name; 137 int ret; 138 //int referral_count = 0; 139 140 dprintk("--> nfs4_path_walk(,,%s)\n", path); 141 142 fsinfo.fattr = &fattr; 143 nfs_fattr_init(&fattr); 144 145 if (*path++ != '/') { 146 dprintk("nfs4_get_root: Path does not begin with a slash\n"); 147 return -EINVAL; 148 } 149 150 /* Start by getting the root filehandle from the server */ 151 ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); 152 if (ret < 0) { 153 dprintk("nfs4_get_root: getroot error = %d\n", -ret); 154 return ret; 155 } 156 157 if (fattr.type != NFDIR) { 158 printk(KERN_ERR "nfs4_get_root:" 159 " getroot encountered non-directory\n"); 160 return -ENOTDIR; 161 } 162 163 if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { 164 printk(KERN_ERR "nfs4_get_root:" 165 " getroot obtained referral\n"); 166 return -EREMOTE; 167 } 168 169 next_component: 170 dprintk("Next: %s\n", path); 171 172 /* extract the next bit of the path */ 173 if (!*path) 174 goto path_walk_complete; 175 176 name.name = path; 177 while (*path && *path != '/') 178 path++; 179 name.len = path - (const char *) name.name; 180 181 eat_dot_dir: 182 while (*path == '/') 183 path++; 184 185 if (path[0] == '.' && (path[1] == '/' || !path[1])) { 186 path += 2; 187 goto eat_dot_dir; 188 } 189 190 if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2]) 191 ) { 192 printk(KERN_ERR "nfs4_get_root:" 193 " Mount path contains reference to \"..\"\n"); 194 return -EINVAL; 195 } 196 197 /* lookup the next FH in the sequence */ 198 memcpy(&lastfh, mntfh, sizeof(lastfh)); 199 200 dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path); 201 202 ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name, 203 mntfh, &fattr); 204 if (ret < 0) { 205 dprintk("nfs4_get_root: getroot error = %d\n", -ret); 206 return ret; 207 } 208 209 if (fattr.type != NFDIR) { 210 printk(KERN_ERR "nfs4_get_root:" 211 " lookupfh encountered non-directory\n"); 212 return -ENOTDIR; 213 } 214 215 if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { 216 printk(KERN_ERR "nfs4_get_root:" 217 " lookupfh obtained referral\n"); 218 return -EREMOTE; 219 } 220 221 goto next_component; 222 223 path_walk_complete: 224 memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid)); 225 dprintk("<-- nfs4_path_walk() = 0\n"); 226 return 0; 227 } 228 229 /* 230 * get an NFS4 root dentry from the root filehandle 231 */ 232 struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) 233 { 234 struct nfs_server *server = NFS_SB(sb); 235 struct nfs_fattr fattr; 236 struct dentry *mntroot; 237 struct inode *inode; 238 int error; 239 240 dprintk("--> nfs4_get_root()\n"); 241 242 /* create a dummy root dentry with dummy inode for this superblock */ 243 if (!sb->s_root) { 244 struct nfs_fh dummyfh; 245 struct dentry *root; 246 struct inode *iroot; 247 248 memset(&dummyfh, 0, sizeof(dummyfh)); 249 memset(&fattr, 0, sizeof(fattr)); 250 nfs_fattr_init(&fattr); 251 fattr.valid = NFS_ATTR_FATTR; 252 fattr.type = NFDIR; 253 fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; 254 fattr.nlink = 2; 255 256 iroot = nfs_fhget(sb, &dummyfh, &fattr); 257 if (IS_ERR(iroot)) 258 return ERR_PTR(PTR_ERR(iroot)); 259 260 root = d_alloc_root(iroot); 261 if (!root) { 262 iput(iroot); 263 return ERR_PTR(-ENOMEM); 264 } 265 266 sb->s_root = root; 267 } 268 269 /* get the info about the server and filesystem */ 270 error = nfs4_server_capabilities(server, mntfh); 271 if (error < 0) { 272 dprintk("nfs_get_root: getcaps error = %d\n", 273 -error); 274 return ERR_PTR(error); 275 } 276 277 /* get the actual root for this mount */ 278 error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr); 279 if (error < 0) { 280 dprintk("nfs_get_root: getattr error = %d\n", -error); 281 return ERR_PTR(error); 282 } 283 284 inode = nfs_fhget(sb, mntfh, &fattr); 285 if (IS_ERR(inode)) { 286 dprintk("nfs_get_root: get root inode failed\n"); 287 return ERR_PTR(PTR_ERR(inode)); 288 } 289 290 /* root dentries normally start off anonymous and get spliced in later 291 * if the dentry tree reaches them; however if the dentry already 292 * exists, we'll pick it up at this point and use it as the root 293 */ 294 mntroot = d_alloc_anon(inode); 295 if (!mntroot) { 296 iput(inode); 297 dprintk("nfs_get_root: get root dentry failed\n"); 298 return ERR_PTR(-ENOMEM); 299 } 300 301 security_d_instantiate(mntroot, inode); 302 303 if (!mntroot->d_op) 304 mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; 305 306 dprintk("<-- nfs4_get_root()\n"); 307 return mntroot; 308 } 309 310 #endif /* CONFIG_NFS_V4 */ 311