[net-next-2.6.git] / fs / nfs / getroot.c

/* 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;
		}
		/* Circumvent igrab(): we know the inode is not being freed */
		atomic_inc(&inode->i_count);
		/*
		 * 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(&dcache_lock);
		list_del_init(&sb->s_root->d_alias);
		spin_unlock(&dcache_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)
{
	struct nfs_server *server = NFS_SB(sb);
	struct nfs_fsinfo fsinfo;
	struct dentry *ret;
	struct inode *inode;
	int error;

	/* get the actual root for this mount */
	fsinfo.fattr = nfs_alloc_fattr();
	if (fsinfo.fattr == NULL)
		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);

	if (ret->d_op == NULL)
		ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
out:
	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)
{
	struct nfs_server *server = NFS_SB(sb);
	struct nfs_fattr *fattr = NULL;
	struct dentry *ret;
	struct inode *inode;
	int error;

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

	/* 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);
		return ERR_PTR(error);
	}

	fattr = nfs_alloc_fattr();
	if (fattr == NULL)
		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;
	}

	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);

	if (ret->d_op == NULL)
		ret->d_op = server->nfs_client->rpc_ops->dentry_ops;

out:
	nfs_free_fattr(fattr);
	dprintk("<-- nfs4_get_root()\n");
	return ret;
}

#endif /* CONFIG_NFS_V4 */
Commit	Line	Data
54ceac45 DH	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
54ceac45 DH	12	#include <linux/module.h>
	13	#include <linux/init.h>
	14
	15	#include <linux/time.h>
	16	#include <linux/kernel.h>
	17	#include <linux/mm.h>
	18	#include <linux/string.h>
	19	#include <linux/stat.h>
	20	#include <linux/errno.h>
	21	#include <linux/unistd.h>
	22	#include <linux/sunrpc/clnt.h>
	23	#include <linux/sunrpc/stats.h>
	24	#include <linux/nfs_fs.h>
	25	#include <linux/nfs_mount.h>
	26	#include <linux/nfs4_mount.h>
	27	#include <linux/lockd/bind.h>
54ceac45 DH	28	#include <linux/seq_file.h>
	29	#include <linux/mount.h>
	30	#include <linux/nfs_idmap.h>
	31	#include <linux/vfs.h>
	32	#include <linux/namei.h>
738a3519	33	#include <linux/security.h>
54ceac45 DH	34
	35	#include <asm/system.h>
	36	#include <asm/uaccess.h>
	37
	38	#include "nfs4_fs.h"
	39	#include "delegation.h"
	40	#include "internal.h"
	41
	42	#define NFSDBG_FACILITY NFSDBG_CLIENT
54ceac45	43
b09b9417 TM	44	/*
	45	* Set the superblock root dentry.
	46	* Note that this function frees the inode in case of error.
	47	*/
	48	static int nfs_superblock_set_dummy_root(struct super_block sb, struct inode inode)
	49	{
	50	/* The mntroot acts as the dummy root dentry for this superblock */
	51	if (sb->s_root == NULL) {
	52	sb->s_root = d_alloc_root(inode);
	53	if (sb->s_root == NULL) {
	54	iput(inode);
	55	return -ENOMEM;
	56	}
	57	/* Circumvent igrab(): we know the inode is not being freed */
	58	atomic_inc(&inode->i_count);
a10db50a TM	59	/*
	60	* Ensure that this dentry is invisible to d_find_alias().
	61	* Otherwise, it may be spliced into the tree by
	62	* d_materialise_unique if a parent directory from the same
	63	* filesystem gets mounted at a later time.
	64	* This again causes shrink_dcache_for_umount_subtree() to
	65	* Oops, since the test for IS_ROOT() will fail.
	66	*/
	67	spin_lock(&dcache_lock);
	68	list_del_init(&sb->s_root->d_alias);
	69	spin_unlock(&dcache_lock);
b09b9417 TM	70	}
	71	return 0;
	72	}
	73
54ceac45 DH	74	/*
	75	* get an NFS2/NFS3 root dentry from the root filehandle
	76	*/
	77	struct dentry nfs_get_root(struct super_block sb, struct nfs_fh *mntfh)
	78	{
	79	struct nfs_server *server = NFS_SB(sb);
	80	struct nfs_fsinfo fsinfo;
8bac9db9	81	struct dentry *ret;
54ceac45 DH	82	struct inode *inode;
	83	int error;
	84
54ceac45	85	/* get the actual root for this mount */
8bac9db9 TM	86	fsinfo.fattr = nfs_alloc_fattr();
	87	if (fsinfo.fattr == NULL)
	88	return ERR_PTR(-ENOMEM);
54ceac45 DH	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);
8bac9db9 TM	93	ret = ERR_PTR(error);
8bac9db9 TM	94	goto out;
54ceac45 DH	95	}
	96
	97	inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
	98	if (IS_ERR(inode)) {
	99	dprintk("nfs_get_root: get root inode failed\n");
8bac9db9 TM	100	ret = ERR_CAST(inode);
8bac9db9 TM	101	goto out;
54ceac45 DH	102	}
54ceac45 DH	103
b09b9417	104	error = nfs_superblock_set_dummy_root(sb, inode);
8bac9db9 TM	105	if (error != 0) {
	106	ret = ERR_PTR(error);
	107	goto out;
	108	}
b09b9417	109
54ceac45 DH	110	/* root dentries normally start off anonymous and get spliced in later
	111	* if the dentry tree reaches them; however if the dentry already
	112	* exists, we'll pick it up at this point and use it as the root
	113	*/
8bac9db9 TM	114	ret = d_obtain_alias(inode);
8bac9db9 TM	115	if (IS_ERR(ret)) {
54ceac45	116	dprintk("nfs_get_root: get root dentry failed\n");
8bac9db9	117	goto out;
54ceac45 DH	118	}
54ceac45 DH	119
8bac9db9	120	security_d_instantiate(ret, inode);
738a3519	121
8bac9db9 TM	122	if (ret->d_op == NULL)
	123	ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
	124	out:
	125	nfs_free_fattr(fsinfo.fattr);
	126	return ret;
54ceac45 DH	127	}
	128
	129	#ifdef CONFIG_NFS_V4
	130
815409d2	131	int nfs4_get_rootfh(struct nfs_server server, struct nfs_fh mntfh)
54ceac45 DH	132	{
54ceac45 DH	133	struct nfs_fsinfo fsinfo;
815409d2	134	int ret = -ENOMEM;
54ceac45	135
815409d2	136	dprintk("--> nfs4_get_rootfh()\n");
54ceac45	137
815409d2 TM	138	fsinfo.fattr = nfs_alloc_fattr();
	139	if (fsinfo.fattr == NULL)
	140	goto out;
54ceac45 DH	141
	142	/* Start by getting the root filehandle from the server */
	143	ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
	144	if (ret < 0) {
815409d2 TM	145	dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
815409d2 TM	146	goto out;
54ceac45 DH	147	}
54ceac45 DH	148
f799bdb3	149	if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE)
815409d2 TM	150	\|\| !S_ISDIR(fsinfo.fattr->mode)) {
815409d2 TM	151	printk(KERN_ERR "nfs4_get_rootfh:"
54ceac45	152	" getroot encountered non-directory\n");
815409d2 TM	153	ret = -ENOTDIR;
815409d2 TM	154	goto out;
54ceac45 DH	155	}
54ceac45 DH	156
815409d2 TM	157	if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
815409d2 TM	158	printk(KERN_ERR "nfs4_get_rootfh:"
54ceac45	159	" getroot obtained referral\n");
815409d2 TM	160	ret = -EREMOTE;
815409d2 TM	161	goto out;
54ceac45 DH	162	}
54ceac45 DH	163
815409d2 TM	164	memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid));
	165	out:
	166	nfs_free_fattr(fsinfo.fattr);
	167	dprintk("<-- nfs4_get_rootfh() = %d\n", ret);
	168	return ret;
54ceac45 DH	169	}
	170
	171	/*
	172	* get an NFS4 root dentry from the root filehandle
	173	*/
	174	struct dentry nfs4_get_root(struct super_block sb, struct nfs_fh *mntfh)
	175	{
	176	struct nfs_server *server = NFS_SB(sb);
8bac9db9 TM	177	struct nfs_fattr *fattr = NULL;
8bac9db9 TM	178	struct dentry *ret;
54ceac45 DH	179	struct inode *inode;
	180	int error;
	181
	182	dprintk("--> nfs4_get_root()\n");
	183
54ceac45 DH	184	/* get the info about the server and filesystem */
	185	error = nfs4_server_capabilities(server, mntfh);
	186	if (error < 0) {
	187	dprintk("nfs_get_root: getcaps error = %d\n",
	188	-error);
	189	return ERR_PTR(error);
	190	}
	191
8bac9db9 TM	192	fattr = nfs_alloc_fattr();
	193	if (fattr == NULL)
	194	return ERR_PTR(-ENOMEM);;
	195
54ceac45	196	/* get the actual root for this mount */
8bac9db9	197	error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
54ceac45 DH	198	if (error < 0) {
54ceac45 DH	199	dprintk("nfs_get_root: getattr error = %d\n", -error);
8bac9db9 TM	200	ret = ERR_PTR(error);
8bac9db9 TM	201	goto out;
54ceac45 DH	202	}
54ceac45 DH	203
8bac9db9	204	inode = nfs_fhget(sb, mntfh, fattr);
54ceac45 DH	205	if (IS_ERR(inode)) {
54ceac45 DH	206	dprintk("nfs_get_root: get root inode failed\n");
8bac9db9 TM	207	ret = ERR_CAST(inode);
8bac9db9 TM	208	goto out;
54ceac45 DH	209	}
54ceac45 DH	210
b09b9417	211	error = nfs_superblock_set_dummy_root(sb, inode);
8bac9db9 TM	212	if (error != 0) {
	213	ret = ERR_PTR(error);
	214	goto out;
	215	}
b09b9417	216
54ceac45 DH	217	/* root dentries normally start off anonymous and get spliced in later
	218	* if the dentry tree reaches them; however if the dentry already
	219	* exists, we'll pick it up at this point and use it as the root
	220	*/
8bac9db9 TM	221	ret = d_obtain_alias(inode);
8bac9db9 TM	222	if (IS_ERR(ret)) {
54ceac45	223	dprintk("nfs_get_root: get root dentry failed\n");
8bac9db9	224	goto out;
54ceac45 DH	225	}
54ceac45 DH	226
8bac9db9	227	security_d_instantiate(ret, inode);
738a3519	228
8bac9db9 TM	229	if (ret->d_op == NULL)
8bac9db9 TM	230	ret->d_op = server->nfs_client->rpc_ops->dentry_ops;
54ceac45	231
8bac9db9 TM	232	out:
8bac9db9 TM	233	nfs_free_fattr(fattr);
54ceac45	234	dprintk("<-- nfs4_get_root()\n");
8bac9db9	235	return ret;
54ceac45 DH	236	}
	237
	238	#endif /* CONFIG_NFS_V4 */