[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/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include "internal.h"
#include "nfs4_fs.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

/*
 * Check if fs_root is valid
 */
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",
			__FUNCTION__, path, fs_path);
		return -ENOENT;
	}

	return 0;
}

/*
 * Check if the string represents a "valid" IPv4 address
 */
static inline int valid_ipaddr4(const char *buf)
{
	int rc, count, in[4];

	rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
	if (rc != 4)
		return -EINVAL;
	for (count = 0; count < 4; count++) {
		if (in[count] > 255)
			return -EINVAL;
	}
	return 0;
}

/**
 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
 * @mnt_parent - mountpoint of parent directory
 * @dentry - parent directory
 * @fspath - fs path returned in fs_locations
 * @mntpath - mount path to new server
 * @hostname - hostname of new server
 * @addr - host addr of new server
 *
 */
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, s, error;

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

	dprintk("%s: referral at %s/%s\n", __FUNCTION__,
		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;
	}

	loc = 0;
	while (loc < locations->nlocations && IS_ERR(mnt)) {
		const struct nfs4_fs_location *location = &locations->locations[loc];
		char *mnt_path;

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

		mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
		if (IS_ERR(mnt_path)) {
			loc++;
			continue;
		}
		mountdata.mnt_path = mnt_path;

		s = 0;
		while (s < location->nservers) {
			struct sockaddr_in addr = {};

			if (location->servers[s].len <= 0 ||
			    valid_ipaddr4(location->servers[s].data) < 0) {
				s++;
				continue;
			}

			mountdata.hostname = location->servers[s].data;
			addr.sin_addr.s_addr = in_aton(mountdata.hostname);
			addr.sin_family = AF_INET;
			addr.sin_port = htons(NFS_PORT);
			mountdata.addr = &addr;

			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;
			}
			s++;
		}
		loc++;
	}

out:
	free_page((unsigned long) page);
	free_page((unsigned long) page2);
	dprintk("%s: done\n", __FUNCTION__);
	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", __FUNCTION__);

	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",
		__FUNCTION__, 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", __FUNCTION__);
	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>
	14	#include <linux/string.h>
	15	#include <linux/sunrpc/clnt.h>
	16	#include <linux/vfs.h>
	17	#include <linux/inet.h>
	18	#include "internal.h"
c228fd3a	19	#include "nfs4_fs.h"
f7b422b1 DH	20
	21	#define NFSDBG_FACILITY NFSDBG_VFS
	22
	23	/*
	24	* Check if fs_root is valid
	25	*/
509de811	26	static inline char nfs4_pathname_string(const struct nfs4_pathname pathname,
f7b422b1 DH	27	char *buffer, ssize_t buflen)
	28	{
	29	char *end = buffer + buflen;
	30	int n;
	31
	32	*--end = '\0';
	33	buflen--;
	34
	35	n = pathname->ncomponents;
	36	while (--n >= 0) {
509de811	37	const struct nfs4_string *component = &pathname->components[n];
f7b422b1 DH	38	buflen -= component->len + 1;
	39	if (buflen < 0)
	40	goto Elong;
	41	end -= component->len;
	42	memcpy(end, component->data, component->len);
	43	*--end = '/';
	44	}
	45	return end;
	46	Elong:
	47	return ERR_PTR(-ENAMETOOLONG);
	48	}
	49
54ceac45 DH	50	/*
	51	* Determine the mount path as a string
	52	*/
	53	static char nfs4_path(const struct vfsmount mnt_parent,
	54	const struct dentry *dentry,
	55	char *buffer, ssize_t buflen)
	56	{
	57	const char *srvpath;
	58
	59	srvpath = strchr(mnt_parent->mnt_devname, ':');
	60	if (srvpath)
	61	srvpath++;
	62	else
	63	srvpath = mnt_parent->mnt_devname;
	64
	65	return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen);
	66	}
	67
	68	/*
	69	* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
	70	* believe to be the server path to this dentry
	71	*/
	72	static int nfs4_validate_fspath(const struct vfsmount *mnt_parent,
	73	const struct dentry *dentry,
	74	const struct nfs4_fs_locations *locations,
	75	char page, char page2)
	76	{
	77	const char path, fs_path;
	78
	79	path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE);
	80	if (IS_ERR(path))
	81	return PTR_ERR(path);
	82
	83	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	84	if (IS_ERR(fs_path))
	85	return PTR_ERR(fs_path);
	86
	87	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
	88	dprintk("%s: path %s does not begin with fsroot %s\n",
	89	__FUNCTION__, path, fs_path);
	90	return -ENOENT;
	91	}
	92
	93	return 0;
	94	}
	95
	96	/*
	97	* Check if the string represents a "valid" IPv4 address
	98	*/
	99	static inline int valid_ipaddr4(const char *buf)
	100	{
	101	int rc, count, in[4];
	102
	103	rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
	104	if (rc != 4)
	105	return -EINVAL;
	106	for (count = 0; count < 4; count++) {
	107	if (in[count] > 255)
	108	return -EINVAL;
	109	}
	110	return 0;
	111	}
f7b422b1 DH	112
	113	/**
	114	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
	115	* @mnt_parent - mountpoint of parent directory
	116	* @dentry - parent directory
	117	* @fspath - fs path returned in fs_locations
	118	* @mntpath - mount path to new server
	119	* @hostname - hostname of new server
	120	* @addr - host addr of new server
	121	*
	122	*/
	123	static struct vfsmount nfs_follow_referral(const struct vfsmount mnt_parent,
	124	const struct dentry *dentry,
509de811	125	const struct nfs4_fs_locations *locations)
f7b422b1 DH	126	{
	127	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	128	struct nfs_clone_mount mountdata = {
	129	.sb = mnt_parent->mnt_sb,
	130	.dentry = dentry,
	131	.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
	132	};
54ceac45	133	char page = NULL, page2 = NULL;
54ceac45	134	int loc, s, error;
f7b422b1 DH	135
	136	if (locations == NULL \|\| locations->nlocations <= 0)
	137	goto out;
	138
	139	dprintk("%s: referral at %s/%s\n", __FUNCTION__,
	140	dentry->d_parent->d_name.name, dentry->d_name.name);
	141
f7b422b1	142	page = (char *) __get_free_page(GFP_USER);
54ceac45	143	if (!page)
f7b422b1	144	goto out;
54ceac45	145
f7b422b1	146	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	147	if (!page2)
f7b422b1 DH	148	goto out;
f7b422b1 DH	149
54ceac45 DH	150	/* Ensure fs path is a prefix of current dentry path */
	151	error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
	152	if (error < 0) {
	153	mnt = ERR_PTR(error);
	154	goto out;
f7b422b1 DH	155	}
f7b422b1 DH	156
f7b422b1 DH	157	loc = 0;
f7b422b1 DH	158	while (loc < locations->nlocations && IS_ERR(mnt)) {
509de811	159	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	160	char *mnt_path;
	161
	162	if (location == NULL \|\| location->nservers <= 0 \|\|
	163	location->rootpath.ncomponents == 0) {
	164	loc++;
	165	continue;
	166	}
	167
	168	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	169	if (IS_ERR(mnt_path)) {
	170	loc++;
	171	continue;
	172	}
	173	mountdata.mnt_path = mnt_path;
	174
	175	s = 0;
	176	while (s < location->nservers) {
	177	struct sockaddr_in addr = {};
	178
	179	if (location->servers[s].len <= 0 \|\|
	180	valid_ipaddr4(location->servers[s].data) < 0) {
	181	s++;
	182	continue;
	183	}
	184
	185	mountdata.hostname = location->servers[s].data;
	186	addr.sin_addr.s_addr = in_aton(mountdata.hostname);
	187	addr.sin_family = AF_INET;
	188	addr.sin_port = htons(NFS_PORT);
	189	mountdata.addr = &addr;
	190
588a700b TM	191	snprintf(page, PAGE_SIZE, "%s:%s",
	192	mountdata.hostname,
	193	mountdata.mnt_path);
	194
	195	mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, &mountdata);
f7b422b1 DH	196	if (!IS_ERR(mnt)) {
	197	break;
	198	}
	199	s++;
	200	}
	201	loc++;
	202	}
	203
f7b422b1	204	out:
54ceac45 DH	205	free_page((unsigned long) page);
54ceac45 DH	206	free_page((unsigned long) page2);
f7b422b1 DH	207	dprintk("%s: done\n", __FUNCTION__);
	208	return mnt;
	209	}
	210
	211	/*
	212	* nfs_do_refmount - handle crossing a referral on server
	213	* @dentry - dentry of referral
	214	* @nd - nameidata info
	215	*
	216	*/
	217	struct vfsmount nfs_do_refmount(const struct vfsmount mnt_parent, struct dentry *dentry)
	218	{
54ceac45	219	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	220	struct dentry *parent;
	221	struct nfs4_fs_locations *fs_locations = NULL;
	222	struct page *page;
	223	int err;
	224
	225	/* BUG_ON(IS_ROOT(dentry)); */
	226	dprintk("%s: enter\n", __FUNCTION__);
	227
	228	page = alloc_page(GFP_KERNEL);
	229	if (page == NULL)
	230	goto out;
	231
	232	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	233	if (fs_locations == NULL)
	234	goto out_free;
	235
	236	/* Get locations */
54ceac45 DH	237	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	238
f7b422b1	239	parent = dget_parent(dentry);
54ceac45 DH	240	dprintk("%s: getting locations for %s/%s\n",
	241	__FUNCTION__, parent->d_name.name, dentry->d_name.name);
	242
c228fd3a	243	err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
f7b422b1	244	dput(parent);
54ceac45 DH	245	if (err != 0 \|\|
54ceac45 DH	246	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	247	fs_locations->fs_path.ncomponents <= 0)
	248	goto out_free;
	249
	250	mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
	251	out_free:
	252	__free_page(page);
	253	kfree(fs_locations);
	254	out:
	255	dprintk("%s: done\n", __FUNCTION__);
	256	return mnt;
	257	}