[linux.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 ([email protected])
 *
 * 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 */
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 ([email protected])
	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	}
7de9c6ee	57	ihold(inode);
a10db50a TM	58	/*
	59	* Ensure that this dentry is invisible to d_find_alias().
	60	* Otherwise, it may be spliced into the tree by
	61	* d_materialise_unique if a parent directory from the same
	62	* filesystem gets mounted at a later time.
	63	* This again causes shrink_dcache_for_umount_subtree() to
	64	* Oops, since the test for IS_ROOT() will fail.
	65	*/
873feea0	66	spin_lock(&sb->s_root->d_inode->i_lock);
b23fb0a6	67	spin_lock(&sb->s_root->d_lock);
a10db50a	68	list_del_init(&sb->s_root->d_alias);
b23fb0a6	69	spin_unlock(&sb->s_root->d_lock);
873feea0	70	spin_unlock(&sb->s_root->d_inode->i_lock);
b09b9417 TM	71	}
	72	return 0;
	73	}
	74
54ceac45 DH	75	/*
	76	* get an NFS2/NFS3 root dentry from the root filehandle
	77	*/
0d5839ad AV	78	struct dentry nfs_get_root(struct super_block sb, struct nfs_fh *mntfh,
0d5839ad AV	79	const char *devname)
54ceac45 DH	80	{
	81	struct nfs_server *server = NFS_SB(sb);
	82	struct nfs_fsinfo fsinfo;
8bac9db9	83	struct dentry *ret;
54ceac45	84	struct inode *inode;
b1942c5f	85	void *name = kstrdup(devname, GFP_KERNEL);
54ceac45 DH	86	int error;
54ceac45 DH	87
b1942c5f AV	88	if (!name)
	89	return ERR_PTR(-ENOMEM);
	90
54ceac45	91	/* get the actual root for this mount */
8bac9db9	92	fsinfo.fattr = nfs_alloc_fattr();
b1942c5f AV	93	if (fsinfo.fattr == NULL) {
b1942c5f AV	94	kfree(name);
8bac9db9	95	return ERR_PTR(-ENOMEM);
b1942c5f	96	}
54ceac45 DH	97
	98	error = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
	99	if (error < 0) {
	100	dprintk("nfs_get_root: getattr error = %d\n", -error);
8bac9db9 TM	101	ret = ERR_PTR(error);
8bac9db9 TM	102	goto out;
54ceac45 DH	103	}
	104
	105	inode = nfs_fhget(sb, mntfh, fsinfo.fattr);
	106	if (IS_ERR(inode)) {
	107	dprintk("nfs_get_root: get root inode failed\n");
8bac9db9 TM	108	ret = ERR_CAST(inode);
8bac9db9 TM	109	goto out;
54ceac45 DH	110	}
54ceac45 DH	111
b09b9417	112	error = nfs_superblock_set_dummy_root(sb, inode);
8bac9db9 TM	113	if (error != 0) {
	114	ret = ERR_PTR(error);
	115	goto out;
	116	}
b09b9417	117
54ceac45 DH	118	/* root dentries normally start off anonymous and get spliced in later
	119	* if the dentry tree reaches them; however if the dentry already
	120	* exists, we'll pick it up at this point and use it as the root
	121	*/
8bac9db9 TM	122	ret = d_obtain_alias(inode);
8bac9db9 TM	123	if (IS_ERR(ret)) {
54ceac45	124	dprintk("nfs_get_root: get root dentry failed\n");
8bac9db9	125	goto out;
54ceac45 DH	126	}
54ceac45 DH	127
8bac9db9	128	security_d_instantiate(ret, inode);
b1942c5f AV	129	spin_lock(&ret->d_lock);
	130	if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
	131	ret->d_fsdata = name;
	132	name = NULL;
	133	}
	134	spin_unlock(&ret->d_lock);
8bac9db9	135	out:
b1942c5f AV	136	if (name)
b1942c5f AV	137	kfree(name);
8bac9db9 TM	138	nfs_free_fattr(fsinfo.fattr);
8bac9db9 TM	139	return ret;
54ceac45 DH	140	}
	141
	142	#ifdef CONFIG_NFS_V4
	143
815409d2	144	int nfs4_get_rootfh(struct nfs_server server, struct nfs_fh mntfh)
54ceac45 DH	145	{
54ceac45 DH	146	struct nfs_fsinfo fsinfo;
815409d2	147	int ret = -ENOMEM;
54ceac45	148
815409d2	149	dprintk("--> nfs4_get_rootfh()\n");
54ceac45	150
815409d2 TM	151	fsinfo.fattr = nfs_alloc_fattr();
	152	if (fsinfo.fattr == NULL)
	153	goto out;
54ceac45 DH	154
	155	/* Start by getting the root filehandle from the server */
	156	ret = server->nfs_client->rpc_ops->getroot(server, mntfh, &fsinfo);
	157	if (ret < 0) {
815409d2 TM	158	dprintk("nfs4_get_rootfh: getroot error = %d\n", -ret);
815409d2 TM	159	goto out;
54ceac45 DH	160	}
54ceac45 DH	161
f799bdb3	162	if (!(fsinfo.fattr->valid & NFS_ATTR_FATTR_TYPE)
815409d2 TM	163	\|\| !S_ISDIR(fsinfo.fattr->mode)) {
815409d2 TM	164	printk(KERN_ERR "nfs4_get_rootfh:"
54ceac45	165	" getroot encountered non-directory\n");
815409d2 TM	166	ret = -ENOTDIR;
815409d2 TM	167	goto out;
54ceac45 DH	168	}
54ceac45 DH	169
815409d2 TM	170	if (fsinfo.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
815409d2 TM	171	printk(KERN_ERR "nfs4_get_rootfh:"
54ceac45	172	" getroot obtained referral\n");
815409d2 TM	173	ret = -EREMOTE;
815409d2 TM	174	goto out;
54ceac45 DH	175	}
54ceac45 DH	176
815409d2 TM	177	memcpy(&server->fsid, &fsinfo.fattr->fsid, sizeof(server->fsid));
	178	out:
	179	nfs_free_fattr(fsinfo.fattr);
	180	dprintk("<-- nfs4_get_rootfh() = %d\n", ret);
	181	return ret;
54ceac45 DH	182	}
	183
	184	/*
	185	* get an NFS4 root dentry from the root filehandle
	186	*/
0d5839ad AV	187	struct dentry nfs4_get_root(struct super_block sb, struct nfs_fh *mntfh,
0d5839ad AV	188	const char *devname)
54ceac45 DH	189	{
54ceac45 DH	190	struct nfs_server *server = NFS_SB(sb);
8bac9db9 TM	191	struct nfs_fattr *fattr = NULL;
8bac9db9 TM	192	struct dentry *ret;
54ceac45	193	struct inode *inode;
b1942c5f	194	void *name = kstrdup(devname, GFP_KERNEL);
54ceac45 DH	195	int error;
	196
	197	dprintk("--> nfs4_get_root()\n");
	198
b1942c5f AV	199	if (!name)
	200	return ERR_PTR(-ENOMEM);
	201
54ceac45 DH	202	/* get the info about the server and filesystem */
	203	error = nfs4_server_capabilities(server, mntfh);
	204	if (error < 0) {
	205	dprintk("nfs_get_root: getcaps error = %d\n",
	206	-error);
b1942c5f	207	kfree(name);
54ceac45 DH	208	return ERR_PTR(error);
	209	}
	210
8bac9db9	211	fattr = nfs_alloc_fattr();
b1942c5f AV	212	if (fattr == NULL) {
	213	kfree(name);
	214	return ERR_PTR(-ENOMEM);
	215	}
8bac9db9	216
54ceac45	217	/* get the actual root for this mount */
8bac9db9	218	error = server->nfs_client->rpc_ops->getattr(server, mntfh, fattr);
54ceac45 DH	219	if (error < 0) {
54ceac45 DH	220	dprintk("nfs_get_root: getattr error = %d\n", -error);
8bac9db9 TM	221	ret = ERR_PTR(error);
8bac9db9 TM	222	goto out;
54ceac45 DH	223	}
54ceac45 DH	224
4667058b GV	225	if (fattr->valid & NFS_ATTR_FATTR_FSID &&
	226	!nfs_fsid_equal(&server->fsid, &fattr->fsid))
	227	memcpy(&server->fsid, &fattr->fsid, sizeof(server->fsid));
	228
8bac9db9	229	inode = nfs_fhget(sb, mntfh, fattr);
54ceac45 DH	230	if (IS_ERR(inode)) {
54ceac45 DH	231	dprintk("nfs_get_root: get root inode failed\n");
8bac9db9 TM	232	ret = ERR_CAST(inode);
8bac9db9 TM	233	goto out;
54ceac45 DH	234	}
54ceac45 DH	235
b09b9417	236	error = nfs_superblock_set_dummy_root(sb, inode);
8bac9db9 TM	237	if (error != 0) {
	238	ret = ERR_PTR(error);
	239	goto out;
	240	}
b09b9417	241
54ceac45 DH	242	/* root dentries normally start off anonymous and get spliced in later
	243	* if the dentry tree reaches them; however if the dentry already
	244	* exists, we'll pick it up at this point and use it as the root
	245	*/
8bac9db9 TM	246	ret = d_obtain_alias(inode);
8bac9db9 TM	247	if (IS_ERR(ret)) {
54ceac45	248	dprintk("nfs_get_root: get root dentry failed\n");
8bac9db9	249	goto out;
54ceac45 DH	250	}
54ceac45 DH	251
8bac9db9	252	security_d_instantiate(ret, inode);
b1942c5f AV	253	spin_lock(&ret->d_lock);
	254	if (IS_ROOT(ret) && !(ret->d_flags & DCACHE_NFSFS_RENAMED)) {
	255	ret->d_fsdata = name;
	256	name = NULL;
	257	}
	258	spin_unlock(&ret->d_lock);
8bac9db9	259	out:
b1942c5f AV	260	if (name)
b1942c5f AV	261	kfree(name);
8bac9db9	262	nfs_free_fattr(fattr);
54ceac45	263	dprintk("<-- nfs4_get_root()\n");
8bac9db9	264	return ret;
54ceac45 DH	265	}
	266
	267	#endif /* CONFIG_NFS_V4 */