154ceac45SDavid Howells /* getroot.c: get the root dentry for an NFS mount 254ceac45SDavid Howells * 354ceac45SDavid Howells * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved. 454ceac45SDavid Howells * Written by David Howells (dhowells@redhat.com) 554ceac45SDavid Howells * 654ceac45SDavid Howells * This program is free software; you can redistribute it and/or 754ceac45SDavid Howells * modify it under the terms of the GNU General Public License 854ceac45SDavid Howells * as published by the Free Software Foundation; either version 954ceac45SDavid Howells * 2 of the License, or (at your option) any later version. 1054ceac45SDavid Howells */ 1154ceac45SDavid Howells 1254ceac45SDavid Howells #include <linux/module.h> 1354ceac45SDavid Howells #include <linux/init.h> 1454ceac45SDavid Howells 1554ceac45SDavid Howells #include <linux/time.h> 1654ceac45SDavid Howells #include <linux/kernel.h> 1754ceac45SDavid Howells #include <linux/mm.h> 1854ceac45SDavid Howells #include <linux/string.h> 1954ceac45SDavid Howells #include <linux/stat.h> 2054ceac45SDavid Howells #include <linux/errno.h> 2154ceac45SDavid Howells #include <linux/unistd.h> 2254ceac45SDavid Howells #include <linux/sunrpc/clnt.h> 2354ceac45SDavid Howells #include <linux/sunrpc/stats.h> 2454ceac45SDavid Howells #include <linux/nfs_fs.h> 2554ceac45SDavid Howells #include <linux/nfs_mount.h> 2654ceac45SDavid Howells #include <linux/nfs4_mount.h> 2754ceac45SDavid Howells #include <linux/lockd/bind.h> 2854ceac45SDavid Howells #include <linux/seq_file.h> 2954ceac45SDavid Howells #include <linux/mount.h> 3054ceac45SDavid Howells #include <linux/nfs_idmap.h> 3154ceac45SDavid Howells #include <linux/vfs.h> 3254ceac45SDavid Howells #include <linux/namei.h> 336b3286edSKirill Korotaev #include <linux/mnt_namespace.h> 34738a3519SDavid Howells #include <linux/security.h> 3554ceac45SDavid Howells 3654ceac45SDavid Howells #include <asm/system.h> 3754ceac45SDavid Howells #include <asm/uaccess.h> 3854ceac45SDavid Howells 3954ceac45SDavid Howells #include "nfs4_fs.h" 4054ceac45SDavid Howells #include "delegation.h" 4154ceac45SDavid Howells #include "internal.h" 4254ceac45SDavid Howells 4354ceac45SDavid Howells #define NFSDBG_FACILITY NFSDBG_CLIENT 4454ceac45SDavid Howells 4554ceac45SDavid Howells /* 46b09b9417STrond Myklebust * Set the superblock root dentry. 47b09b9417STrond Myklebust * Note that this function frees the inode in case of error. 48b09b9417STrond Myklebust */ 49b09b9417STrond Myklebust static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode) 50b09b9417STrond Myklebust { 51b09b9417STrond Myklebust /* The mntroot acts as the dummy root dentry for this superblock */ 52b09b9417STrond Myklebust if (sb->s_root == NULL) { 53b09b9417STrond Myklebust sb->s_root = d_alloc_root(inode); 54b09b9417STrond Myklebust if (sb->s_root == NULL) { 55b09b9417STrond Myklebust iput(inode); 56b09b9417STrond Myklebust return -ENOMEM; 57b09b9417STrond Myklebust } 58b09b9417STrond Myklebust /* Circumvent igrab(): we know the inode is not being freed */ 59b09b9417STrond Myklebust atomic_inc(&inode->i_count); 60b09b9417STrond Myklebust } 61b09b9417STrond Myklebust return 0; 62b09b9417STrond Myklebust } 63b09b9417STrond Myklebust 64b09b9417STrond Myklebust /* 6554ceac45SDavid Howells * get an NFS2/NFS3 root dentry from the root filehandle 6654ceac45SDavid Howells */ 6754ceac45SDavid Howells struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh) 6854ceac45SDavid Howells { 6954ceac45SDavid Howells struct nfs_server *server = NFS_SB(sb); 7054ceac45SDavid Howells struct nfs_fsinfo fsinfo; 7154ceac45SDavid Howells struct nfs_fattr fattr; 7254ceac45SDavid Howells struct dentry *mntroot; 7354ceac45SDavid Howells struct inode *inode; 7454ceac45SDavid Howells int error; 7554ceac45SDavid Howells 7654ceac45SDavid Howells /* get the actual root for this mount */ 7754ceac45SDavid Howells fsinfo.fattr = &fattr; 7854ceac45SDavid Howells 7954ceac45SDavid Howells error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); 8054ceac45SDavid Howells if (error < 0) { 8154ceac45SDavid Howells dprintk("nfs_get_root: getattr error = %d\n", -error); 8254ceac45SDavid Howells return ERR_PTR(error); 8354ceac45SDavid Howells } 8454ceac45SDavid Howells 8554ceac45SDavid Howells inode = nfs_fhget(sb, mntfh, fsinfo.fattr); 8654ceac45SDavid Howells if (IS_ERR(inode)) { 8754ceac45SDavid Howells dprintk("nfs_get_root: get root inode failed\n"); 8854ceac45SDavid Howells return ERR_PTR(PTR_ERR(inode)); 8954ceac45SDavid Howells } 9054ceac45SDavid Howells 91b09b9417STrond Myklebust error = nfs_superblock_set_dummy_root(sb, inode); 92b09b9417STrond Myklebust if (error != 0) 93b09b9417STrond Myklebust return ERR_PTR(error); 94b09b9417STrond Myklebust 9554ceac45SDavid Howells /* root dentries normally start off anonymous and get spliced in later 9654ceac45SDavid Howells * if the dentry tree reaches them; however if the dentry already 9754ceac45SDavid Howells * exists, we'll pick it up at this point and use it as the root 9854ceac45SDavid Howells */ 9954ceac45SDavid Howells mntroot = d_alloc_anon(inode); 10054ceac45SDavid Howells if (!mntroot) { 10154ceac45SDavid Howells iput(inode); 10254ceac45SDavid Howells dprintk("nfs_get_root: get root dentry failed\n"); 10354ceac45SDavid Howells return ERR_PTR(-ENOMEM); 10454ceac45SDavid Howells } 10554ceac45SDavid Howells 106738a3519SDavid Howells security_d_instantiate(mntroot, inode); 107738a3519SDavid Howells 10854ceac45SDavid Howells if (!mntroot->d_op) 10954ceac45SDavid Howells mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; 11054ceac45SDavid Howells 11154ceac45SDavid Howells return mntroot; 11254ceac45SDavid Howells } 11354ceac45SDavid Howells 11454ceac45SDavid Howells #ifdef CONFIG_NFS_V4 11554ceac45SDavid Howells 11654ceac45SDavid Howells /* 11754ceac45SDavid Howells * Do a simple pathwalk from the root FH of the server to the nominated target 11854ceac45SDavid Howells * of the mountpoint 11954ceac45SDavid Howells * - give error on symlinks 12054ceac45SDavid Howells * - give error on ".." occurring in the path 12154ceac45SDavid Howells * - follow traversals 12254ceac45SDavid Howells */ 12354ceac45SDavid Howells int nfs4_path_walk(struct nfs_server *server, 12454ceac45SDavid Howells struct nfs_fh *mntfh, 12554ceac45SDavid Howells const char *path) 12654ceac45SDavid Howells { 12754ceac45SDavid Howells struct nfs_fsinfo fsinfo; 12854ceac45SDavid Howells struct nfs_fattr fattr; 12954ceac45SDavid Howells struct nfs_fh lastfh; 13054ceac45SDavid Howells struct qstr name; 13154ceac45SDavid Howells int ret; 13254ceac45SDavid Howells 13354ceac45SDavid Howells dprintk("--> nfs4_path_walk(,,%s)\n", path); 13454ceac45SDavid Howells 13554ceac45SDavid Howells fsinfo.fattr = &fattr; 13654ceac45SDavid Howells nfs_fattr_init(&fattr); 13754ceac45SDavid Howells 138faebf4e2STrond Myklebust /* Eat leading slashes */ 139faebf4e2STrond Myklebust while (*path == '/') 140faebf4e2STrond Myklebust path++; 14154ceac45SDavid Howells 14254ceac45SDavid Howells /* Start by getting the root filehandle from the server */ 14354ceac45SDavid Howells ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo); 14454ceac45SDavid Howells if (ret < 0) { 14554ceac45SDavid Howells dprintk("nfs4_get_root: getroot error = %d\n", -ret); 14654ceac45SDavid Howells return ret; 14754ceac45SDavid Howells } 14854ceac45SDavid Howells 14954ceac45SDavid Howells if (fattr.type != NFDIR) { 15054ceac45SDavid Howells printk(KERN_ERR "nfs4_get_root:" 15154ceac45SDavid Howells " getroot encountered non-directory\n"); 15254ceac45SDavid Howells return -ENOTDIR; 15354ceac45SDavid Howells } 15454ceac45SDavid Howells 155faebf4e2STrond Myklebust /* FIXME: It is quite valid for the server to return a referral here */ 15654ceac45SDavid Howells if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { 15754ceac45SDavid Howells printk(KERN_ERR "nfs4_get_root:" 15854ceac45SDavid Howells " getroot obtained referral\n"); 15954ceac45SDavid Howells return -EREMOTE; 16054ceac45SDavid Howells } 16154ceac45SDavid Howells 16254ceac45SDavid Howells next_component: 16354ceac45SDavid Howells dprintk("Next: %s\n", path); 16454ceac45SDavid Howells 16554ceac45SDavid Howells /* extract the next bit of the path */ 16654ceac45SDavid Howells if (!*path) 16754ceac45SDavid Howells goto path_walk_complete; 16854ceac45SDavid Howells 16954ceac45SDavid Howells name.name = path; 17054ceac45SDavid Howells while (*path && *path != '/') 17154ceac45SDavid Howells path++; 17254ceac45SDavid Howells name.len = path - (const char *) name.name; 17354ceac45SDavid Howells 17454af3bb5STrond Myklebust if (name.len > NFS4_MAXNAMLEN) 17554af3bb5STrond Myklebust return -ENAMETOOLONG; 17654af3bb5STrond Myklebust 17754ceac45SDavid Howells eat_dot_dir: 17854ceac45SDavid Howells while (*path == '/') 17954ceac45SDavid Howells path++; 18054ceac45SDavid Howells 18154ceac45SDavid Howells if (path[0] == '.' && (path[1] == '/' || !path[1])) { 18254ceac45SDavid Howells path += 2; 18354ceac45SDavid Howells goto eat_dot_dir; 18454ceac45SDavid Howells } 18554ceac45SDavid Howells 186faebf4e2STrond Myklebust /* FIXME: Why shouldn't the user be able to use ".." in the path? */ 18754ceac45SDavid Howells if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2]) 18854ceac45SDavid Howells ) { 18954ceac45SDavid Howells printk(KERN_ERR "nfs4_get_root:" 19054ceac45SDavid Howells " Mount path contains reference to \"..\"\n"); 19154ceac45SDavid Howells return -EINVAL; 19254ceac45SDavid Howells } 19354ceac45SDavid Howells 19454ceac45SDavid Howells /* lookup the next FH in the sequence */ 19554ceac45SDavid Howells memcpy(&lastfh, mntfh, sizeof(lastfh)); 19654ceac45SDavid Howells 19754ceac45SDavid Howells dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path); 19854ceac45SDavid Howells 19954ceac45SDavid Howells ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name, 20054ceac45SDavid Howells mntfh, &fattr); 20154ceac45SDavid Howells if (ret < 0) { 20254ceac45SDavid Howells dprintk("nfs4_get_root: getroot error = %d\n", -ret); 20354ceac45SDavid Howells return ret; 20454ceac45SDavid Howells } 20554ceac45SDavid Howells 20654ceac45SDavid Howells if (fattr.type != NFDIR) { 20754ceac45SDavid Howells printk(KERN_ERR "nfs4_get_root:" 20854ceac45SDavid Howells " lookupfh encountered non-directory\n"); 20954ceac45SDavid Howells return -ENOTDIR; 21054ceac45SDavid Howells } 21154ceac45SDavid Howells 212faebf4e2STrond Myklebust /* FIXME: Referrals are quite valid here too */ 21354ceac45SDavid Howells if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) { 21454ceac45SDavid Howells printk(KERN_ERR "nfs4_get_root:" 21554ceac45SDavid Howells " lookupfh obtained referral\n"); 21654ceac45SDavid Howells return -EREMOTE; 21754ceac45SDavid Howells } 21854ceac45SDavid Howells 21954ceac45SDavid Howells goto next_component; 22054ceac45SDavid Howells 22154ceac45SDavid Howells path_walk_complete: 22254ceac45SDavid Howells memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid)); 22354ceac45SDavid Howells dprintk("<-- nfs4_path_walk() = 0\n"); 22454ceac45SDavid Howells return 0; 22554ceac45SDavid Howells } 22654ceac45SDavid Howells 22754ceac45SDavid Howells /* 22854ceac45SDavid Howells * get an NFS4 root dentry from the root filehandle 22954ceac45SDavid Howells */ 23054ceac45SDavid Howells struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh) 23154ceac45SDavid Howells { 23254ceac45SDavid Howells struct nfs_server *server = NFS_SB(sb); 23354ceac45SDavid Howells struct nfs_fattr fattr; 23454ceac45SDavid Howells struct dentry *mntroot; 23554ceac45SDavid Howells struct inode *inode; 23654ceac45SDavid Howells int error; 23754ceac45SDavid Howells 23854ceac45SDavid Howells dprintk("--> nfs4_get_root()\n"); 23954ceac45SDavid Howells 24054ceac45SDavid Howells /* get the info about the server and filesystem */ 24154ceac45SDavid Howells error = nfs4_server_capabilities(server, mntfh); 24254ceac45SDavid Howells if (error < 0) { 24354ceac45SDavid Howells dprintk("nfs_get_root: getcaps error = %d\n", 24454ceac45SDavid Howells -error); 24554ceac45SDavid Howells return ERR_PTR(error); 24654ceac45SDavid Howells } 24754ceac45SDavid Howells 24854ceac45SDavid Howells /* get the actual root for this mount */ 24954ceac45SDavid Howells error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr); 25054ceac45SDavid Howells if (error < 0) { 25154ceac45SDavid Howells dprintk("nfs_get_root: getattr error = %d\n", -error); 25254ceac45SDavid Howells return ERR_PTR(error); 25354ceac45SDavid Howells } 25454ceac45SDavid Howells 25554ceac45SDavid Howells inode = nfs_fhget(sb, mntfh, &fattr); 25654ceac45SDavid Howells if (IS_ERR(inode)) { 25754ceac45SDavid Howells dprintk("nfs_get_root: get root inode failed\n"); 25854ceac45SDavid Howells return ERR_PTR(PTR_ERR(inode)); 25954ceac45SDavid Howells } 26054ceac45SDavid Howells 261b09b9417STrond Myklebust error = nfs_superblock_set_dummy_root(sb, inode); 262b09b9417STrond Myklebust if (error != 0) 263b09b9417STrond Myklebust return ERR_PTR(error); 264b09b9417STrond Myklebust 26554ceac45SDavid Howells /* root dentries normally start off anonymous and get spliced in later 26654ceac45SDavid Howells * if the dentry tree reaches them; however if the dentry already 26754ceac45SDavid Howells * exists, we'll pick it up at this point and use it as the root 26854ceac45SDavid Howells */ 26954ceac45SDavid Howells mntroot = d_alloc_anon(inode); 27054ceac45SDavid Howells if (!mntroot) { 27154ceac45SDavid Howells iput(inode); 27254ceac45SDavid Howells dprintk("nfs_get_root: get root dentry failed\n"); 27354ceac45SDavid Howells return ERR_PTR(-ENOMEM); 27454ceac45SDavid Howells } 27554ceac45SDavid Howells 276738a3519SDavid Howells security_d_instantiate(mntroot, inode); 277738a3519SDavid Howells 27854ceac45SDavid Howells if (!mntroot->d_op) 27954ceac45SDavid Howells mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops; 28054ceac45SDavid Howells 28154ceac45SDavid Howells dprintk("<-- nfs4_get_root()\n"); 28254ceac45SDavid Howells return mntroot; 28354ceac45SDavid Howells } 28454ceac45SDavid Howells 28554ceac45SDavid Howells #endif /* CONFIG_NFS_V4 */ 286