2874c5fd28
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
130 lines
3.3 KiB
C
130 lines
3.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* 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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#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/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/vfs.h>
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#include <linux/namei.h>
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#include <linux/security.h>
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#include <linux/uaccess.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_make_root(inode);
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if (sb->s_root == NULL)
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return -ENOMEM;
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ihold(inode);
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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_splice_alias 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(&d_inode(sb->s_root)->i_lock);
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spin_lock(&sb->s_root->d_lock);
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hlist_del_init(&sb->s_root->d_u.d_alias);
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spin_unlock(&sb->s_root->d_lock);
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spin_unlock(&d_inode(sb->s_root)->i_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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const char *devname)
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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 dentry *ret;
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struct inode *inode;
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void *name = kstrdup(devname, GFP_KERNEL);
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int error;
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if (!name)
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return ERR_PTR(-ENOMEM);
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/* get the actual root for this mount */
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fsinfo.fattr = nfs_alloc_fattr();
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if (fsinfo.fattr == NULL) {
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kfree(name);
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return ERR_PTR(-ENOMEM);
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}
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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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ret = ERR_PTR(error);
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goto out;
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}
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inode = nfs_fhget(sb, mntfh, fsinfo.fattr, NULL);
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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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ret = ERR_CAST(inode);
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goto out;
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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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ret = ERR_PTR(error);
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goto out;
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}
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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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ret = d_obtain_root(inode);
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if (IS_ERR(ret)) {
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dprintk("nfs_get_root: get root dentry failed\n");
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goto out;
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}
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security_d_instantiate(ret, inode);
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spin_lock(&ret->d_lock);
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if (IS_ROOT(ret) && !ret->d_fsdata &&
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!(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
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ret->d_fsdata = name;
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name = NULL;
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}
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spin_unlock(&ret->d_lock);
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out:
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kfree(name);
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nfs_free_fattr(fsinfo.fattr);
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return ret;
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}
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