fs/nfs/getroot.c - kernel/mindspeed - Git at Google

 /* getroot.c: get the root dentry for an NFS mount
  *
  * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * 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.
  */

 #include <linux/module.h>
 #include <linux/init.h>

 #include <linux/time.h>
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/string.h>
 #include <linux/stat.h>
 #include <linux/errno.h>
 #include <linux/unistd.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/stats.h>
 #include <linux/nfs_fs.h>
 #include <linux/nfs_mount.h>
 #include <linux/nfs4_mount.h>
 #include <linux/lockd/bind.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
 #include <linux/nfs_idmap.h>
 #include <linux/vfs.h>
 #include <linux/namei.h>
 #include <linux/security.h>

 #include <asm/system.h>
 #include <asm/uaccess.h>

 #include "nfs4_fs.h"
 #include "delegation.h"
 #include "internal.h"

 #define NFSDBG_FACILITY		NFSDBG_CLIENT

 /*
  * Set the superblock root dentry.
  * Note that this function frees the inode in case of error.
  */
 static int nfs_superblock_set_dummy_root(struct super_block *sb, struct inode *inode)
 {
 	/* The mntroot acts as the dummy root dentry for this superblock */
 	if (sb->s_root == NULL) {
 		sb->s_root = d_alloc_root(inode);
 		if (sb->s_root == NULL) {
 			iput(inode);
 			return -ENOMEM;
 		}
 		ihold(inode);
 		/*
 		 * Ensure that this dentry is invisible to d_find_alias().
 		 * Otherwise, it may be spliced into the tree by
 		 * d_materialise_unique if a parent directory from the same
 		 * filesystem gets mounted at a later time.
 		 * This again causes shrink_dcache_for_umount_subtree() to
 		 * Oops, since the test for IS_ROOT() will fail.
 		 */
 		spin_lock(&sb->s_root->d_inode->i_lock);
 		spin_lock(&sb->s_root->d_lock);
 		list_del_init(&sb->s_root->d_alias);
 		spin_unlock(&sb->s_root->d_lock);
 		spin_unlock(&sb->s_root->d_inode->i_lock);
 	}
 	return 0;
 }

 /*
  * get an NFS2/NFS3 root dentry from the root filehandle
  */
 struct dentry *nfs_get_root(struct super_block *sb, struct nfs_fh *mntfh,
 			    const char *devname)
 {
 	struct nfs_server *server = NFS_SB(sb);
 	struct nfs_fsinfo fsinfo;
 	struct dentry *ret;
 	struct inode *inode;
 	void *name = kstrdup(devname, GFP_KERNEL);
 	int error;

 	if (!name)
 		return ERR_PTR(-ENOMEM);

 	/* get the actual root for this mount */
 	fsinfo.fattr = nfs_alloc_fattr();
 	if (fsinfo.fattr == NULL) {
 		kfree(name);
 		return ERR_PTR(-ENOMEM);
 	}

 	error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
 	if (error < 0) {
 		dprintk("nfs_get_root: getattr error = %d\n", -error);
 		ret = ERR_PTR(error);
 		goto out;
 	}

 	inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
 	if (IS_ERR(inode)) {
 		dprintk("nfs_get_root: get root inode failed\n");
 		ret = ERR_CAST(inode);
 		goto out;
 	}

 	error = nfs_superblock_set_dummy_root(sb, inode);
 	if (error != 0) {
 		ret = ERR_PTR(error);
 		goto out;
 	}

 	/* root dentries normally start off anonymous and get spliced in later
 	 * if the dentry tree reaches them; however if the dentry already
 	 * exists, we'll pick it up at this point and use it as the root
 	 */
 	ret = d_obtain_alias(inode);
 	if (IS_ERR(ret)) {
 		dprintk("nfs_get_root: get root dentry failed\n");
 		goto out;
 	}

 	security_d_instantiate(ret, inode);
 	spin_lock(&ret->d_lock);
 	if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
 		ret->d_fsdata = name;
 		name = NULL;
 	}
 	spin_unlock(&ret->d_lock);
 out:
 	if (name)
 		kfree(name);
 	nfs_free_fattr(fsinfo.fattr);
 	return ret;
 }

 #ifdef CONFIG_NFS_V4

 int nfs4_get_rootfh(struct nfs_server *server, struct nfs_fh *mntfh)
 {
 	struct nfs_fsinfo fsinfo;
 	int ret = -ENOMEM;

 	dprintk("--> nfs4_get_rootfh()\n");

 	fsinfo.fattr = nfs_alloc_fattr();
 	if (fsinfo.fattr == NULL)
 		goto out;

 	/* Start by getting the root filehandle from the server */
 	ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
 	if (ret < 0) {
 		dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
 		goto out;
 	}

 	if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE)
 			|| !S_ISDIR(fsinfo.fattr->mode)) {
 		printk(KERN_ERR "nfs4_get_rootfh:"
 		       " getroot encountered non-directory\n");
 		ret = -ENOTDIR;
 		goto out;
 	}

 	if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
 		printk(KERN_ERR "nfs4_get_rootfh:"
 		       " getroot obtained referral\n");
 		ret = -EREMOTE;
 		goto out;
 	}

 	memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid));
 out:
 	nfs_free_fattr(fsinfo.fattr);
 	dprintk("<-- nfs4_get_rootfh() = %d\n", ret);
 	return ret;
 }

 /*
  * get an NFS4 root dentry from the root filehandle
  */
 struct dentry *nfs4_get_root(struct super_block *sb, struct nfs_fh *mntfh,
 			     const char *devname)
 {
 	struct nfs_server *server = NFS_SB(sb);
 	struct nfs_fattr *fattr = NULL;
 	struct dentry *ret;
 	struct inode *inode;
 	void *name = kstrdup(devname, GFP_KERNEL);
 	int error;

 	dprintk("--> nfs4_get_root()\n");

 	if (!name)
 		return ERR_PTR(-ENOMEM);

 	/* get the info about the server and filesystem */
 	error = nfs4_server_capabilities(server, mntfh);
 	if (error < 0) {
 		dprintk("nfs_get_root: getcaps error = %d\n",
 			-error);
 		kfree(name);
 		return ERR_PTR(error);
 	}

 	fattr = nfs_alloc_fattr();
 	if (fattr == NULL) {
 		kfree(name);
 		return ERR_PTR(-ENOMEM);
 	}

 	/* get the actual root for this mount */
 	error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
 	if (error < 0) {
 		dprintk("nfs_get_root: getattr error = %d\n", -error);
 		ret = ERR_PTR(error);
 		goto out;
 	}

 	if (fattr->valid & NFS_ATTR_FATTR_FSID &&
 	    !nfs_fsid_equal(&server->fsid, &fattr->fsid))
 		memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));

 	inode = nfs_fhget(sb, mntfh, fattr);
 	if (IS_ERR(inode)) {
 		dprintk("nfs_get_root: get root inode failed\n");
 		ret = ERR_CAST(inode);
 		goto out;
 	}

 	error = nfs_superblock_set_dummy_root(sb, inode);
 	if (error != 0) {
 		ret = ERR_PTR(error);
 		goto out;
 	}

 	/* root dentries normally start off anonymous and get spliced in later
 	 * if the dentry tree reaches them; however if the dentry already
 	 * exists, we'll pick it up at this point and use it as the root
 	 */
 	ret = d_obtain_alias(inode);
 	if (IS_ERR(ret)) {
 		dprintk("nfs_get_root: get root dentry failed\n");
 		goto out;
 	}

 	security_d_instantiate(ret, inode);
 	spin_lock(&ret->d_lock);
 	if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
 		ret->d_fsdata = name;
 		name = NULL;
 	}
 	spin_unlock(&ret->d_lock);
 out:
 	if (name)
 		kfree(name);
 	nfs_free_fattr(fattr);
 	dprintk("<-- nfs4_get_root()\n");
 	return ret;
 }

 #endif /* CONFIG_NFS_V4 */
	/* getroot.c: get the root dentry for an NFS mount
	*
	* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
	* Written by David Howells (dhowells@redhat.com)
	*
	* 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.
	*/

	#include <linux/module.h>
	#include <linux/init.h>

	#include <linux/time.h>
	#include <linux/kernel.h>
	#include <linux/mm.h>
	#include <linux/string.h>
	#include <linux/stat.h>
	#include <linux/errno.h>
	#include <linux/unistd.h>
	#include <linux/sunrpc/clnt.h>
	#include <linux/sunrpc/stats.h>
	#include <linux/nfs_fs.h>
	#include <linux/nfs_mount.h>
	#include <linux/nfs4_mount.h>
	#include <linux/lockd/bind.h>
	#include <linux/seq_file.h>
	#include <linux/mount.h>
	#include <linux/nfs_idmap.h>
	#include <linux/vfs.h>
	#include <linux/namei.h>
	#include <linux/security.h>

	#include <asm/system.h>
	#include <asm/uaccess.h>

	#include "nfs4_fs.h"
	#include "delegation.h"
	#include "internal.h"

	#define NFSDBG_FACILITY NFSDBG_CLIENT

	/*
	* Set the superblock root dentry.
	* Note that this function frees the inode in case of error.
	*/
	static int nfs_superblock_set_dummy_root(struct super_block sb, struct inode inode)
	{
	/* The mntroot acts as the dummy root dentry for this superblock */
	if (sb->s_root == NULL) {
	sb->s_root = d_alloc_root(inode);
	if (sb->s_root == NULL) {
	iput(inode);
	return -ENOMEM;
	}
	ihold(inode);
	/*
	* Ensure that this dentry is invisible to d_find_alias().
	* Otherwise, it may be spliced into the tree by
	* d_materialise_unique if a parent directory from the same
	* filesystem gets mounted at a later time.
	* This again causes shrink_dcache_for_umount_subtree() to
	* Oops, since the test for IS_ROOT() will fail.
	*/
	spin_lock(&sb->s_root->d_inode->i_lock);
	spin_lock(&sb->s_root->d_lock);
	list_del_init(&sb->s_root->d_alias);
	spin_unlock(&sb->s_root->d_lock);
	spin_unlock(&sb->s_root->d_inode->i_lock);
	}
	return 0;
	}

	/*
	* get an NFS2/NFS3 root dentry from the root filehandle
	*/
	struct dentry nfs_get_root(struct super_block sb, struct nfs_fh *mntfh,
	const char *devname)
	{
	struct nfs_server *server = NFS_SB(sb);
	struct nfs_fsinfo fsinfo;
	struct dentry *ret;
	struct inode *inode;
	void *name = kstrdup(devname, GFP_KERNEL);
	int error;

	if (!name)
	return ERR_PTR(-ENOMEM);

	/* get the actual root for this mount */
	fsinfo.fattr = nfs_alloc_fattr();
	if (fsinfo.fattr == NULL) {
	kfree(name);
	return ERR_PTR(-ENOMEM);
	}

	error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
	if (error < 0) {
	dprintk("nfs_get_root: getattr error = %d\n", -error);
	ret = ERR_PTR(error);
	goto out;
	}

	inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
	if (IS_ERR(inode)) {
	dprintk("nfs_get_root: get root inode failed\n");
	ret = ERR_CAST(inode);
	goto out;
	}

	error = nfs_superblock_set_dummy_root(sb, inode);
	if (error != 0) {
	ret = ERR_PTR(error);
	goto out;
	}

	/* root dentries normally start off anonymous and get spliced in later
	* if the dentry tree reaches them; however if the dentry already
	* exists, we'll pick it up at this point and use it as the root
	*/
	ret = d_obtain_alias(inode);
	if (IS_ERR(ret)) {
	dprintk("nfs_get_root: get root dentry failed\n");
	goto out;
	}

	security_d_instantiate(ret, inode);
	spin_lock(&ret->d_lock);
	if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
	ret->d_fsdata = name;
	name = NULL;
	}
	spin_unlock(&ret->d_lock);
	out:
	if (name)
	kfree(name);
	nfs_free_fattr(fsinfo.fattr);
	return ret;
	}

	#ifdef CONFIG_NFS_V4

	int nfs4_get_rootfh(struct nfs_server server, struct nfs_fh mntfh)
	{
	struct nfs_fsinfo fsinfo;
	int ret = -ENOMEM;

	dprintk("--> nfs4_get_rootfh()\n");

	fsinfo.fattr = nfs_alloc_fattr();
	if (fsinfo.fattr == NULL)
	goto out;

	/* Start by getting the root filehandle from the server */
	ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
	if (ret < 0) {
	dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
	goto out;
	}

	if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE)
	\|\| !S_ISDIR(fsinfo.fattr->mode)) {
	printk(KERN_ERR "nfs4_get_rootfh:"
	" getroot encountered non-directory\n");
	ret = -ENOTDIR;
	goto out;
	}

	if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
	printk(KERN_ERR "nfs4_get_rootfh:"
	" getroot obtained referral\n");
	ret = -EREMOTE;
	goto out;
	}

	memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid));
	out:
	nfs_free_fattr(fsinfo.fattr);
	dprintk("<-- nfs4_get_rootfh() = %d\n", ret);
	return ret;
	}

	/*
	* get an NFS4 root dentry from the root filehandle
	*/
	struct dentry nfs4_get_root(struct super_block sb, struct nfs_fh *mntfh,
	const char *devname)
	{
	struct nfs_server *server = NFS_SB(sb);
	struct nfs_fattr *fattr = NULL;
	struct dentry *ret;
	struct inode *inode;
	void *name = kstrdup(devname, GFP_KERNEL);
	int error;

	dprintk("--> nfs4_get_root()\n");

	if (!name)
	return ERR_PTR(-ENOMEM);

	/* get the info about the server and filesystem */
	error = nfs4_server_capabilities(server, mntfh);
	if (error < 0) {
	dprintk("nfs_get_root: getcaps error = %d\n",
	-error);
	kfree(name);
	return ERR_PTR(error);
	}

	fattr = nfs_alloc_fattr();
	if (fattr == NULL) {
	kfree(name);
	return ERR_PTR(-ENOMEM);
	}

	/* get the actual root for this mount */
	error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
	if (error < 0) {
	dprintk("nfs_get_root: getattr error = %d\n", -error);
	ret = ERR_PTR(error);
	goto out;
	}

	if (fattr->valid & NFS_ATTR_FATTR_FSID &&
	!nfs_fsid_equal(&server->fsid, &fattr->fsid))
	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));

	inode = nfs_fhget(sb, mntfh, fattr);
	if (IS_ERR(inode)) {
	dprintk("nfs_get_root: get root inode failed\n");
	ret = ERR_CAST(inode);
	goto out;
	}

	error = nfs_superblock_set_dummy_root(sb, inode);
	if (error != 0) {
	ret = ERR_PTR(error);
	goto out;
	}

	/* root dentries normally start off anonymous and get spliced in later
	* if the dentry tree reaches them; however if the dentry already
	* exists, we'll pick it up at this point and use it as the root
	*/
	ret = d_obtain_alias(inode);
	if (IS_ERR(ret)) {
	dprintk("nfs_get_root: get root dentry failed\n");
	goto out;
	}

	security_d_instantiate(ret, inode);
	spin_lock(&ret->d_lock);
	if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
	ret->d_fsdata = name;
	name = NULL;
	}
	spin_unlock(&ret->d_lock);
	out:
	if (name)
	kfree(name);
	nfs_free_fattr(fattr);
	dprintk("<-- nfs4_get_root()\n");
	return ret;
	}

	#endif /* CONFIG_NFS_V4 */