David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 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/config.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/init.h> |
| 15 | |
| 16 | #include <linux/time.h> |
| 17 | #include <linux/kernel.h> |
| 18 | #include <linux/mm.h> |
| 19 | #include <linux/string.h> |
| 20 | #include <linux/stat.h> |
| 21 | #include <linux/errno.h> |
| 22 | #include <linux/unistd.h> |
| 23 | #include <linux/sunrpc/clnt.h> |
| 24 | #include <linux/sunrpc/stats.h> |
| 25 | #include <linux/nfs_fs.h> |
| 26 | #include <linux/nfs_mount.h> |
| 27 | #include <linux/nfs4_mount.h> |
| 28 | #include <linux/lockd/bind.h> |
| 29 | #include <linux/smp_lock.h> |
| 30 | #include <linux/seq_file.h> |
| 31 | #include <linux/mount.h> |
| 32 | #include <linux/nfs_idmap.h> |
| 33 | #include <linux/vfs.h> |
| 34 | #include <linux/namei.h> |
| 35 | #include <linux/namespace.h> |
David Howells | 738a351 | 2006-07-30 14:58:27 -0400 | [diff] [blame] | 36 | #include <linux/security.h> |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 37 | |
| 38 | #include <asm/system.h> |
| 39 | #include <asm/uaccess.h> |
| 40 | |
| 41 | #include "nfs4_fs.h" |
| 42 | #include "delegation.h" |
| 43 | #include "internal.h" |
| 44 | |
| 45 | #define NFSDBG_FACILITY NFSDBG_CLIENT |
| 46 | #define NFS_PARANOIA 1 |
| 47 | |
| 48 | /* |
| 49 | * get an NFS2/NFS3 root dentry from the root filehandle |
| 50 | */ |
| 51 | struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh) |
| 52 | { |
| 53 | struct nfs_server *server = NFS_SB(sb); |
| 54 | struct nfs_fsinfo fsinfo; |
| 55 | struct nfs_fattr fattr; |
| 56 | struct dentry *mntroot; |
| 57 | struct inode *inode; |
| 58 | int error; |
| 59 | |
| 60 | /* create a dummy root dentry with dummy inode for this superblock */ |
| 61 | if (!sb->s_root) { |
| 62 | struct nfs_fh dummyfh; |
| 63 | struct dentry *root; |
| 64 | struct inode *iroot; |
| 65 | |
| 66 | memset(&dummyfh, 0, sizeof(dummyfh)); |
| 67 | memset(&fattr, 0, sizeof(fattr)); |
| 68 | nfs_fattr_init(&fattr); |
| 69 | fattr.valid = NFS_ATTR_FATTR; |
| 70 | fattr.type = NFDIR; |
| 71 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; |
| 72 | fattr.nlink = 2; |
| 73 | |
| 74 | iroot = nfs_fhget(sb, &dummyfh, &fattr); |
| 75 | if (IS_ERR(iroot)) |
| 76 | return ERR_PTR(PTR_ERR(iroot)); |
| 77 | |
| 78 | root = d_alloc_root(iroot); |
| 79 | if (!root) { |
| 80 | iput(iroot); |
| 81 | return ERR_PTR(-ENOMEM); |
| 82 | } |
| 83 | |
| 84 | sb->s_root = root; |
| 85 | } |
| 86 | |
| 87 | /* get the actual root for this mount */ |
| 88 | fsinfo.fattr = &fattr; |
| 89 | |
| 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); |
| 93 | return ERR_PTR(error); |
| 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"); |
| 99 | return ERR_PTR(PTR_ERR(inode)); |
| 100 | } |
| 101 | |
| 102 | /* root dentries normally start off anonymous and get spliced in later |
| 103 | * if the dentry tree reaches them; however if the dentry already |
| 104 | * exists, we'll pick it up at this point and use it as the root |
| 105 | */ |
| 106 | mntroot = d_alloc_anon(inode); |
| 107 | if (!mntroot) { |
| 108 | iput(inode); |
| 109 | dprintk("nfs_get_root: get root dentry failed\n"); |
| 110 | return ERR_PTR(-ENOMEM); |
| 111 | } |
| 112 | |
David Howells | 738a351 | 2006-07-30 14:58:27 -0400 | [diff] [blame] | 113 | security_d_instantiate(mntroot, inode); |
| 114 | |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 115 | if (!mntroot->d_op) |
| 116 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; |
| 117 | |
| 118 | return mntroot; |
| 119 | } |
| 120 | |
| 121 | #ifdef CONFIG_NFS_V4 |
| 122 | |
| 123 | /* |
| 124 | * Do a simple pathwalk from the root FH of the server to the nominated target |
| 125 | * of the mountpoint |
| 126 | * - give error on symlinks |
| 127 | * - give error on ".." occurring in the path |
| 128 | * - follow traversals |
| 129 | */ |
| 130 | int nfs4_path_walk(struct nfs_server *server, |
| 131 | struct nfs_fh *mntfh, |
| 132 | const char *path) |
| 133 | { |
| 134 | struct nfs_fsinfo fsinfo; |
| 135 | struct nfs_fattr fattr; |
| 136 | struct nfs_fh lastfh; |
| 137 | struct qstr name; |
| 138 | int ret; |
| 139 | //int referral_count = 0; |
| 140 | |
| 141 | dprintk("--> nfs4_path_walk(,,%s)\n", path); |
| 142 | |
| 143 | fsinfo.fattr = &fattr; |
| 144 | nfs_fattr_init(&fattr); |
| 145 | |
| 146 | if (*path++ != '/') { |
| 147 | dprintk("nfs4_get_root: Path does not begin with a slash\n"); |
| 148 | return -EINVAL; |
| 149 | } |
| 150 | |
| 151 | /* Start by getting the root filehandle from the server */ |
| 152 | ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); |
| 153 | if (ret < 0) { |
| 154 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); |
| 155 | return ret; |
| 156 | } |
| 157 | |
| 158 | if (fattr.type != NFDIR) { |
| 159 | printk(KERN_ERR "nfs4_get_root:" |
| 160 | " getroot encountered non-directory\n"); |
| 161 | return -ENOTDIR; |
| 162 | } |
| 163 | |
| 164 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { |
| 165 | printk(KERN_ERR "nfs4_get_root:" |
| 166 | " getroot obtained referral\n"); |
| 167 | return -EREMOTE; |
| 168 | } |
| 169 | |
| 170 | next_component: |
| 171 | dprintk("Next: %s\n", path); |
| 172 | |
| 173 | /* extract the next bit of the path */ |
| 174 | if (!*path) |
| 175 | goto path_walk_complete; |
| 176 | |
| 177 | name.name = path; |
| 178 | while (*path && *path != '/') |
| 179 | path++; |
| 180 | name.len = path - (const char *) name.name; |
| 181 | |
| 182 | eat_dot_dir: |
| 183 | while (*path == '/') |
| 184 | path++; |
| 185 | |
| 186 | if (path[0] == '.' && (path[1] == '/' || !path[1])) { |
| 187 | path += 2; |
| 188 | goto eat_dot_dir; |
| 189 | } |
| 190 | |
| 191 | if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2]) |
| 192 | ) { |
| 193 | printk(KERN_ERR "nfs4_get_root:" |
| 194 | " Mount path contains reference to \"..\"\n"); |
| 195 | return -EINVAL; |
| 196 | } |
| 197 | |
| 198 | /* lookup the next FH in the sequence */ |
| 199 | memcpy(&lastfh, mntfh, sizeof(lastfh)); |
| 200 | |
| 201 | dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path); |
| 202 | |
| 203 | ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name, |
| 204 | mntfh, &fattr); |
| 205 | if (ret < 0) { |
| 206 | dprintk("nfs4_get_root: getroot error = %d\n", -ret); |
| 207 | return ret; |
| 208 | } |
| 209 | |
| 210 | if (fattr.type != NFDIR) { |
| 211 | printk(KERN_ERR "nfs4_get_root:" |
| 212 | " lookupfh encountered non-directory\n"); |
| 213 | return -ENOTDIR; |
| 214 | } |
| 215 | |
| 216 | if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { |
| 217 | printk(KERN_ERR "nfs4_get_root:" |
| 218 | " lookupfh obtained referral\n"); |
| 219 | return -EREMOTE; |
| 220 | } |
| 221 | |
| 222 | goto next_component; |
| 223 | |
| 224 | path_walk_complete: |
| 225 | memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid)); |
| 226 | dprintk("<-- nfs4_path_walk() = 0\n"); |
| 227 | return 0; |
| 228 | } |
| 229 | |
| 230 | /* |
| 231 | * get an NFS4 root dentry from the root filehandle |
| 232 | */ |
| 233 | struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) |
| 234 | { |
| 235 | struct nfs_server *server = NFS_SB(sb); |
| 236 | struct nfs_fattr fattr; |
| 237 | struct dentry *mntroot; |
| 238 | struct inode *inode; |
| 239 | int error; |
| 240 | |
| 241 | dprintk("--> nfs4_get_root()\n"); |
| 242 | |
| 243 | /* create a dummy root dentry with dummy inode for this superblock */ |
| 244 | if (!sb->s_root) { |
| 245 | struct nfs_fh dummyfh; |
| 246 | struct dentry *root; |
| 247 | struct inode *iroot; |
| 248 | |
| 249 | memset(&dummyfh, 0, sizeof(dummyfh)); |
| 250 | memset(&fattr, 0, sizeof(fattr)); |
| 251 | nfs_fattr_init(&fattr); |
| 252 | fattr.valid = NFS_ATTR_FATTR; |
| 253 | fattr.type = NFDIR; |
| 254 | fattr.mode = S_IFDIR | S_IRUSR | S_IWUSR; |
| 255 | fattr.nlink = 2; |
| 256 | |
| 257 | iroot = nfs_fhget(sb, &dummyfh, &fattr); |
| 258 | if (IS_ERR(iroot)) |
| 259 | return ERR_PTR(PTR_ERR(iroot)); |
| 260 | |
| 261 | root = d_alloc_root(iroot); |
| 262 | if (!root) { |
| 263 | iput(iroot); |
| 264 | return ERR_PTR(-ENOMEM); |
| 265 | } |
| 266 | |
| 267 | sb->s_root = root; |
| 268 | } |
| 269 | |
| 270 | /* get the info about the server and filesystem */ |
| 271 | error = nfs4_server_capabilities(server, mntfh); |
| 272 | if (error < 0) { |
| 273 | dprintk("nfs_get_root: getcaps error = %d\n", |
| 274 | -error); |
| 275 | return ERR_PTR(error); |
| 276 | } |
| 277 | |
| 278 | /* get the actual root for this mount */ |
| 279 | error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr); |
| 280 | if (error < 0) { |
| 281 | dprintk("nfs_get_root: getattr error = %d\n", -error); |
| 282 | return ERR_PTR(error); |
| 283 | } |
| 284 | |
| 285 | inode = nfs_fhget(sb, mntfh, &fattr); |
| 286 | if (IS_ERR(inode)) { |
| 287 | dprintk("nfs_get_root: get root inode failed\n"); |
| 288 | return ERR_PTR(PTR_ERR(inode)); |
| 289 | } |
| 290 | |
| 291 | /* root dentries normally start off anonymous and get spliced in later |
| 292 | * if the dentry tree reaches them; however if the dentry already |
| 293 | * exists, we'll pick it up at this point and use it as the root |
| 294 | */ |
| 295 | mntroot = d_alloc_anon(inode); |
| 296 | if (!mntroot) { |
| 297 | iput(inode); |
| 298 | dprintk("nfs_get_root: get root dentry failed\n"); |
| 299 | return ERR_PTR(-ENOMEM); |
| 300 | } |
| 301 | |
David Howells | 738a351 | 2006-07-30 14:58:27 -0400 | [diff] [blame] | 302 | security_d_instantiate(mntroot, inode); |
| 303 | |
David Howells | 54ceac4 | 2006-08-22 20:06:13 -0400 | [diff] [blame] | 304 | if (!mntroot->d_op) |
| 305 | mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; |
| 306 | |
| 307 | dprintk("<-- nfs4_get_root()\n"); |
| 308 | return mntroot; |
| 309 | } |
| 310 | |
| 311 | #endif /* CONFIG_NFS_V4 */ |