[linux-2.6-block.git] / fs / nfs / nfs4namespace.c

/*
 * linux/fs/nfs/nfs4namespace.c
 *
 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
 * - Modified by David Howells <dhowells@redhat.com>
 *
 * NFSv4 namespace
 */

#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/nfs_fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include "internal.h"
#include "nfs4_fs.h"
#include "dns_resolve.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

/*
 * Convert the NFSv4 pathname components into a standard posix path.
 *
 * Note that the resulting string will be placed at the end of the buffer
 */
static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
					 char *buffer, ssize_t buflen)
{
	char *end = buffer + buflen;
	int n;

	*--end = '\0';
	buflen--;

	n = pathname->ncomponents;
	while (--n >= 0) {
		const struct nfs4_string *component = &pathname->components[n];
		buflen -= component->len + 1;
		if (buflen < 0)
			goto Elong;
		end -= component->len;
		memcpy(end, component->data, component->len);
		*--end = '/';
	}
	return end;
Elong:
	return ERR_PTR(-ENAMETOOLONG);
}

/*
 * Determine the mount path as a string
 */
static char *nfs4_path(const struct vfsmount *mnt_parent,
		       const struct dentry *dentry,
		       char *buffer, ssize_t buflen)
{
	const char *srvpath;

	srvpath = strchr(mnt_parent->mnt_devname, ':');
	if (srvpath)
		srvpath++;
	else
		srvpath = mnt_parent->mnt_devname;

	return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
}

/*
 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
 * believe to be the server path to this dentry
 */
static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
				const struct dentry *dentry,
				const struct nfs4_fs_locations *locations,
				char *page, char *page2)
{
	const char *path, *fs_path;

	path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
	if (IS_ERR(path))
		return PTR_ERR(path);

	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	if (IS_ERR(fs_path))
		return PTR_ERR(fs_path);

	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
		dprintk("%s: path %s does not begin with fsroot %s\n",
			__func__, path, fs_path);
		return -ENOENT;
	}

	return 0;
}

static size_t nfs_parse_server_name(char *string, size_t len,
		struct sockaddr *sa, size_t salen)
{
	ssize_t ret;

	ret = rpc_pton(string, len, sa, salen);
	if (ret == 0) {
		ret = nfs_dns_resolve_name(string, len, sa, salen);
		if (ret < 0)
			ret = 0;
	}
	return ret;
}

static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
				     char *page, char *page2,
				     const struct nfs4_fs_location *location)
{
	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	char *mnt_path;
	unsigned int maxbuflen;
	unsigned int s;

	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	if (IS_ERR(mnt_path))
		return ERR_CAST(mnt_path);
	mountdata->mnt_path = mnt_path;
	maxbuflen = mnt_path - 1 - page2;

	for (s = 0; s < location->nservers; s++) {
		const struct nfs4_string *buf = &location->servers[s];
		struct sockaddr_storage addr;

		if (buf->len <= 0 || buf->len >= maxbuflen)
			continue;

		if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
			continue;

		mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
				(struct sockaddr *)&addr, sizeof(addr));
		if (mountdata->addrlen == 0)
			continue;

		mountdata->addr = (struct sockaddr *)&addr;
		rpc_set_port(mountdata->addr, NFS_PORT);

		memcpy(page2, buf->data, buf->len);
		page2[buf->len] = '\0';
		mountdata->hostname = page2;

		snprintf(page, PAGE_SIZE, "%s:%s",
				mountdata->hostname,
				mountdata->mnt_path);

		mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
		if (!IS_ERR(mnt))
			break;
	}
	return mnt;
}

/**
 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
 * @mnt_parent - mountpoint of parent directory
 * @dentry - parent directory
 * @locations - array of NFSv4 server location information
 *
 */
static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent,
					    const struct dentry *dentry,
					    const struct nfs4_fs_locations *locations)
{
	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	struct nfs_clone_mount mountdata = {
		.sb = mnt_parent->mnt_sb,
		.dentry = dentry,
		.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
	};
	char *page = NULL, *page2 = NULL;
	int loc, error;

	if (locations == NULL || locations->nlocations <= 0)
		goto out;

	dprintk("%s: referral at %s/%s\n", __func__,
		dentry->d_parent->d_name.name, dentry->d_name.name);

	page = (char *) __get_free_page(GFP_USER);
	if (!page)
		goto out;

	page2 = (char *) __get_free_page(GFP_USER);
	if (!page2)
		goto out;

	/* Ensure fs path is a prefix of current dentry path */
	error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
	if (error < 0) {
		mnt = ERR_PTR(error);
		goto out;
	}

	for (loc = 0; loc < locations->nlocations; loc++) {
		const struct nfs4_fs_location *location = &locations->locations[loc];

		if (location == NULL || location->nservers <= 0 ||
		    location->rootpath.ncomponents == 0)
			continue;

		mnt = try_location(&mountdata, page, page2, location);
		if (!IS_ERR(mnt))
			break;
	}

out:
	free_page((unsigned long) page);
	free_page((unsigned long) page2);
	dprintk("%s: done\n", __func__);
	return mnt;
}

/*
 * nfs_do_refmount - handle crossing a referral on server
 * @dentry - dentry of referral
 * @nd - nameidata info
 *
 */
struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry)
{
	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
	struct dentry *parent;
	struct nfs4_fs_locations *fs_locations = NULL;
	struct page *page;
	int err;

	/* BUG_ON(IS_ROOT(dentry)); */
	dprintk("%s: enter\n", __func__);

	page = alloc_page(GFP_KERNEL);
	if (page == NULL)
		goto out;

	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	if (fs_locations == NULL)
		goto out_free;

	/* Get locations */
	mnt = ERR_PTR(-ENOENT);

	parent = dget_parent(dentry);
	dprintk("%s: getting locations for %s/%s\n",
		__func__, parent->d_name.name, dentry->d_name.name);

	err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
	dput(parent);
	if (err != 0 ||
	    fs_locations->nlocations <= 0 ||
	    fs_locations->fs_path.ncomponents <= 0)
		goto out_free;

	mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
out_free:
	__free_page(page);
	kfree(fs_locations);
out:
	dprintk("%s: done\n", __func__);
	return mnt;
}
Commit	Line	Data
f7b422b1 DH	1	/*
	2	* linux/fs/nfs/nfs4namespace.c
	3	*
	4	* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
54ceac45	5	* - Modified by David Howells <dhowells@redhat.com>
f7b422b1 DH	6	*
	7	* NFSv4 namespace
	8	*/
	9
f7b422b1 DH	10	#include <linux/dcache.h>
	11	#include <linux/mount.h>
	12	#include <linux/namei.h>
	13	#include <linux/nfs_fs.h>
5a0e3ad6	14	#include <linux/slab.h>
f7b422b1 DH	15	#include <linux/string.h>
	16	#include <linux/sunrpc/clnt.h>
	17	#include <linux/vfs.h>
	18	#include <linux/inet.h>
	19	#include "internal.h"
c228fd3a	20	#include "nfs4_fs.h"
7d7ea882	21	#include "dns_resolve.h"
f7b422b1 DH	22
	23	#define NFSDBG_FACILITY NFSDBG_VFS
	24
	25	/*
ef95d31e TM	26	* Convert the NFSv4 pathname components into a standard posix path.
	27	*
	28	* Note that the resulting string will be placed at the end of the buffer
f7b422b1	29	*/
509de811	30	static inline char nfs4_pathname_string(const struct nfs4_pathname pathname,
f7b422b1 DH	31	char *buffer, ssize_t buflen)
	32	{
	33	char *end = buffer + buflen;
	34	int n;
	35
	36	*--end = '\0';
	37	buflen--;
	38
	39	n = pathname->ncomponents;
	40	while (--n >= 0) {
509de811	41	const struct nfs4_string *component = &pathname->components[n];
f7b422b1 DH	42	buflen -= component->len + 1;
	43	if (buflen < 0)
	44	goto Elong;
	45	end -= component->len;
	46	memcpy(end, component->data, component->len);
	47	*--end = '/';
	48	}
	49	return end;
	50	Elong:
	51	return ERR_PTR(-ENAMETOOLONG);
	52	}
	53
54ceac45 DH	54	/*
	55	* Determine the mount path as a string
	56	*/
	57	static char nfs4_path(const struct vfsmount mnt_parent,
	58	const struct dentry *dentry,
	59	char *buffer, ssize_t buflen)
	60	{
	61	const char *srvpath;
	62
	63	srvpath = strchr(mnt_parent->mnt_devname, ':');
	64	if (srvpath)
	65	srvpath++;
	66	else
	67	srvpath = mnt_parent->mnt_devname;
	68
	69	return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
	70	}
	71
	72	/*
	73	* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
	74	* believe to be the server path to this dentry
	75	*/
	76	static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
	77	const struct dentry *dentry,
	78	const struct nfs4_fs_locations *locations,
	79	char page, char page2)
	80	{
	81	const char path, fs_path;
	82
	83	path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
	84	if (IS_ERR(path))
	85	return PTR_ERR(path);
	86
	87	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	88	if (IS_ERR(fs_path))
	89	return PTR_ERR(fs_path);
	90
	91	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
	92	dprintk("%s: path %s does not begin with fsroot %s\n",
3110ff80	93	__func__, path, fs_path);
54ceac45 DH	94	return -ENOENT;
	95	}
	96
	97	return 0;
	98	}
	99
7d7ea882 TM	100	static size_t nfs_parse_server_name(char *string, size_t len,
	101	struct sockaddr *sa, size_t salen)
	102	{
	103	ssize_t ret;
	104
	105	ret = rpc_pton(string, len, sa, salen);
	106	if (ret == 0) {
	107	ret = nfs_dns_resolve_name(string, len, sa, salen);
	108	if (ret < 0)
	109	ret = 0;
	110	}
	111	return ret;
	112	}
	113
4ada29d5 BF	114	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	115	char page, char page2,
	116	const struct nfs4_fs_location *location)
	117	{
	118	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	119	char *mnt_path;
ef95d31e	120	unsigned int maxbuflen;
460cdbc8	121	unsigned int s;
4ada29d5 BF	122
	123	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	124	if (IS_ERR(mnt_path))
517be09d	125	return ERR_CAST(mnt_path);
4ada29d5	126	mountdata->mnt_path = mnt_path;
ef95d31e	127	maxbuflen = mnt_path - 1 - page2;
4ada29d5	128
460cdbc8	129	for (s = 0; s < location->nservers; s++) {
ea31a443 BF	130	const struct nfs4_string *buf = &location->servers[s];
ea31a443 BF	131	struct sockaddr_storage addr;
4ada29d5	132
ef95d31e	133	if (buf->len <= 0 \|\| buf->len >= maxbuflen)
4ada29d5	134	continue;
4ada29d5	135
ea31a443 BF	136	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
ea31a443 BF	137	continue;
517be09d TM	138
	139	mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
	140	(struct sockaddr *)&addr, sizeof(addr));
53a0b9c4	141	if (mountdata->addrlen == 0)
ea31a443	142	continue;
517be09d TM	143
517be09d TM	144	mountdata->addr = (struct sockaddr *)&addr;
ec6ee612	145	rpc_set_port(mountdata->addr, NFS_PORT);
ea31a443	146
ef95d31e TM	147	memcpy(page2, buf->data, buf->len);
ef95d31e TM	148	page2[buf->len] = '\0';
ea31a443	149	mountdata->hostname = page2;
4ada29d5 BF	150
	151	snprintf(page, PAGE_SIZE, "%s:%s",
	152	mountdata->hostname,
	153	mountdata->mnt_path);
	154
	155	mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
	156	if (!IS_ERR(mnt))
	157	break;
4ada29d5 BF	158	}
	159	return mnt;
	160	}
	161
f7b422b1 DH	162	/**
	163	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
	164	* @mnt_parent - mountpoint of parent directory
	165	* @dentry - parent directory
3f43c666	166	* @locations - array of NFSv4 server location information
f7b422b1 DH	167	*
	168	*/
	169	static struct vfsmount nfs_follow_referral(const struct vfsmount mnt_parent,
	170	const struct dentry *dentry,
509de811	171	const struct nfs4_fs_locations *locations)
f7b422b1 DH	172	{
	173	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	174	struct nfs_clone_mount mountdata = {
	175	.sb = mnt_parent->mnt_sb,
	176	.dentry = dentry,
	177	.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
	178	};
54ceac45	179	char page = NULL, page2 = NULL;
3f43c666	180	int loc, error;
f7b422b1 DH	181
	182	if (locations == NULL \|\| locations->nlocations <= 0)
	183	goto out;
	184
3110ff80	185	dprintk("%s: referral at %s/%s\n", __func__,
f7b422b1 DH	186	dentry->d_parent->d_name.name, dentry->d_name.name);
f7b422b1 DH	187
f7b422b1	188	page = (char *) __get_free_page(GFP_USER);
54ceac45	189	if (!page)
f7b422b1	190	goto out;
54ceac45	191
f7b422b1	192	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	193	if (!page2)
f7b422b1 DH	194	goto out;
f7b422b1 DH	195
54ceac45 DH	196	/* Ensure fs path is a prefix of current dentry path */
	197	error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
	198	if (error < 0) {
	199	mnt = ERR_PTR(error);
	200	goto out;
f7b422b1 DH	201	}
f7b422b1 DH	202
460cdbc8	203	for (loc = 0; loc < locations->nlocations; loc++) {
509de811	204	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	205
f7b422b1 DH	206	if (location == NULL \|\| location->nservers <= 0 \|\|
460cdbc8	207	location->rootpath.ncomponents == 0)
f7b422b1	208	continue;
f7b422b1	209
4ada29d5 BF	210	mnt = try_location(&mountdata, page, page2, location);
	211	if (!IS_ERR(mnt))
	212	break;
f7b422b1 DH	213	}
f7b422b1 DH	214
f7b422b1	215	out:
54ceac45 DH	216	free_page((unsigned long) page);
54ceac45 DH	217	free_page((unsigned long) page2);
3110ff80	218	dprintk("%s: done\n", __func__);
f7b422b1 DH	219	return mnt;
	220	}
	221
	222	/*
	223	* nfs_do_refmount - handle crossing a referral on server
	224	* @dentry - dentry of referral
	225	* @nd - nameidata info
	226	*
	227	*/
	228	struct vfsmount nfs_do_refmount(const struct vfsmount mnt_parent, struct dentry *dentry)
	229	{
54ceac45	230	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	231	struct dentry *parent;
	232	struct nfs4_fs_locations *fs_locations = NULL;
	233	struct page *page;
	234	int err;
	235
	236	/* BUG_ON(IS_ROOT(dentry)); */
3110ff80	237	dprintk("%s: enter\n", __func__);
f7b422b1 DH	238
	239	page = alloc_page(GFP_KERNEL);
	240	if (page == NULL)
	241	goto out;
	242
	243	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	244	if (fs_locations == NULL)
	245	goto out_free;
	246
	247	/* Get locations */
54ceac45 DH	248	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	249
f7b422b1	250	parent = dget_parent(dentry);
54ceac45	251	dprintk("%s: getting locations for %s/%s\n",
3110ff80	252	__func__, parent->d_name.name, dentry->d_name.name);
54ceac45	253
c228fd3a	254	err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
f7b422b1	255	dput(parent);
54ceac45 DH	256	if (err != 0 \|\|
54ceac45 DH	257	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	258	fs_locations->fs_path.ncomponents <= 0)
	259	goto out_free;
	260
	261	mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
	262	out_free:
	263	__free_page(page);
	264	kfree(fs_locations);
	265	out:
3110ff80	266	dprintk("%s: done\n", __func__);
f7b422b1 DH	267	return mnt;
f7b422b1 DH	268	}