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![Christoph Hellwig](/assets/img/avatar_default.png)
Switch all users of d_alloc_anon to d_obtain_alias. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
294 lines
7.4 KiB
C
294 lines
7.4 KiB
C
/* getroot.c: get the root dentry for an NFS mount
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*
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* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/time.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/stat.h>
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#include <linux/errno.h>
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#include <linux/unistd.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/stats.h>
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#include <linux/nfs_fs.h>
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#include <linux/nfs_mount.h>
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#include <linux/nfs4_mount.h>
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#include <linux/lockd/bind.h>
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#include <linux/seq_file.h>
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#include <linux/mount.h>
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#include <linux/nfs_idmap.h>
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#include <linux/vfs.h>
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#include <linux/namei.h>
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#include <linux/mnt_namespace.h>
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#include <linux/security.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include "nfs4_fs.h"
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#include "delegation.h"
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#include "internal.h"
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#define NFSDBG_FACILITY NFSDBG_CLIENT
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/*
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* Set the superblock root dentry.
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* Note that this function frees the inode in case of error.
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*/
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static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
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{
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/* The mntroot acts as the dummy root dentry for this superblock */
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if (sb->s_root == NULL) {
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sb->s_root = d_alloc_root(inode);
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if (sb->s_root == NULL) {
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iput(inode);
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return -ENOMEM;
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}
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/* Circumvent igrab(): we know the inode is not being freed */
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atomic_inc(&inode->i_count);
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/*
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* Ensure that this dentry is invisible to d_find_alias().
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* Otherwise, it may be spliced into the tree by
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* d_materialise_unique if a parent directory from the same
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* filesystem gets mounted at a later time.
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* This again causes shrink_dcache_for_umount_subtree() to
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* Oops, since the test for IS_ROOT() will fail.
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*/
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spin_lock(&dcache_lock);
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list_del_init(&sb->s_root->d_alias);
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spin_unlock(&dcache_lock);
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}
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return 0;
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}
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/*
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* get an NFS2/NFS3 root dentry from the root filehandle
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*/
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struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh)
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{
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struct nfs_server *server = NFS_SB(sb);
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struct nfs_fsinfo fsinfo;
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struct nfs_fattr fattr;
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struct dentry *mntroot;
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struct inode *inode;
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int error;
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/* get the actual root for this mount */
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fsinfo.fattr = &fattr;
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error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
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if (error < 0) {
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dprintk("nfs_get_root: getattr error = %d\n", -error);
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return ERR_PTR(error);
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}
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inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
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if (IS_ERR(inode)) {
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dprintk("nfs_get_root: get root inode failed\n");
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return ERR_CAST(inode);
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}
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error = nfs_superblock_set_dummy_root(sb, inode);
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if (error != 0)
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return ERR_PTR(error);
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/* root dentries normally start off anonymous and get spliced in later
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* if the dentry tree reaches them; however if the dentry already
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* exists, we'll pick it up at this point and use it as the root
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*/
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mntroot = d_obtain_alias(inode);
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if (IS_ERR(mntroot)) {
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dprintk("nfs_get_root: get root dentry failed\n");
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return mntroot;
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}
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security_d_instantiate(mntroot, inode);
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if (!mntroot->d_op)
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mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops;
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return mntroot;
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}
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#ifdef CONFIG_NFS_V4
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/*
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* Do a simple pathwalk from the root FH of the server to the nominated target
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* of the mountpoint
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* - give error on symlinks
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* - give error on ".." occurring in the path
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* - follow traversals
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*/
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int nfs4_path_walk(struct nfs_server *server,
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struct nfs_fh *mntfh,
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const char *path)
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{
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struct nfs_fsinfo fsinfo;
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struct nfs_fattr fattr;
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struct nfs_fh lastfh;
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struct qstr name;
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int ret;
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dprintk("--> nfs4_path_walk(,,%s)\n", path);
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fsinfo.fattr = &fattr;
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nfs_fattr_init(&fattr);
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/* Eat leading slashes */
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while (*path == '/')
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path++;
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/* Start by getting the root filehandle from the server */
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ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
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if (ret < 0) {
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dprintk("nfs4_get_root: getroot error = %d\n", -ret);
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return ret;
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}
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if (fattr.type != NFDIR) {
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printk(KERN_ERR "nfs4_get_root:"
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" getroot encountered non-directory\n");
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return -ENOTDIR;
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}
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/* FIXME: It is quite valid for the server to return a referral here */
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if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) {
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printk(KERN_ERR "nfs4_get_root:"
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" getroot obtained referral\n");
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return -EREMOTE;
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}
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next_component:
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dprintk("Next: %s\n", path);
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/* extract the next bit of the path */
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if (!*path)
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goto path_walk_complete;
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name.name = path;
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while (*path && *path != '/')
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path++;
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name.len = path - (const char *) name.name;
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if (name.len > NFS4_MAXNAMLEN)
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return -ENAMETOOLONG;
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eat_dot_dir:
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while (*path == '/')
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path++;
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if (path[0] == '.' && (path[1] == '/' || !path[1])) {
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path += 2;
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goto eat_dot_dir;
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}
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/* FIXME: Why shouldn't the user be able to use ".." in the path? */
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if (path[0] == '.' && path[1] == '.' && (path[2] == '/' || !path[2])
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) {
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printk(KERN_ERR "nfs4_get_root:"
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" Mount path contains reference to \"..\"\n");
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return -EINVAL;
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}
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/* lookup the next FH in the sequence */
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memcpy(&lastfh, mntfh, sizeof(lastfh));
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dprintk("LookupFH: %*.*s [%s]\n", name.len, name.len, name.name, path);
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ret = server->nfs_client->rpc_ops->lookupfh(server, &lastfh, &name,
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mntfh, &fattr);
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if (ret < 0) {
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dprintk("nfs4_get_root: getroot error = %d\n", -ret);
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return ret;
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}
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if (fattr.type != NFDIR) {
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printk(KERN_ERR "nfs4_get_root:"
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" lookupfh encountered non-directory\n");
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return -ENOTDIR;
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}
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/* FIXME: Referrals are quite valid here too */
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if (fattr.valid & NFS_ATTR_FATTR_V4_REFERRAL) {
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printk(KERN_ERR "nfs4_get_root:"
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" lookupfh obtained referral\n");
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return -EREMOTE;
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}
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goto next_component;
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path_walk_complete:
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memcpy(&server->fsid, &fattr.fsid, sizeof(server->fsid));
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dprintk("<-- nfs4_path_walk() = 0\n");
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return 0;
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}
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/*
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* get an NFS4 root dentry from the root filehandle
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*/
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struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh)
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{
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struct nfs_server *server = NFS_SB(sb);
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struct nfs_fattr fattr;
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struct dentry *mntroot;
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struct inode *inode;
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int error;
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dprintk("--> nfs4_get_root()\n");
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/* get the info about the server and filesystem */
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error = nfs4_server_capabilities(server, mntfh);
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if (error < 0) {
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dprintk("nfs_get_root: getcaps error = %d\n",
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-error);
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return ERR_PTR(error);
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}
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/* get the actual root for this mount */
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error = server->nfs_client->rpc_ops->getattr(server, mntfh, &fattr);
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if (error < 0) {
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dprintk("nfs_get_root: getattr error = %d\n", -error);
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return ERR_PTR(error);
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}
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inode = nfs_fhget(sb, mntfh, &fattr);
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if (IS_ERR(inode)) {
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dprintk("nfs_get_root: get root inode failed\n");
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return ERR_CAST(inode);
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}
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error = nfs_superblock_set_dummy_root(sb, inode);
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if (error != 0)
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return ERR_PTR(error);
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/* root dentries normally start off anonymous and get spliced in later
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* if the dentry tree reaches them; however if the dentry already
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* exists, we'll pick it up at this point and use it as the root
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*/
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mntroot = d_obtain_alias(inode);
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if (IS_ERR(mntroot)) {
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dprintk("nfs_get_root: get root dentry failed\n");
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return mntroot;
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}
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security_d_instantiate(mntroot, inode);
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if (!mntroot->d_op)
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mntroot->d_op = server->nfs_client->rpc_ops->dentry_ops;
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dprintk("<-- nfs4_get_root()\n");
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return mntroot;
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}
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#endif /* CONFIG_NFS_V4 */
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