[deliverable/linux.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",
			__func__, 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;
}

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 s = 0;

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

	while (s < location->nservers) {
		struct sockaddr_in addr = {
			.sin_family	= AF_INET,
			.sin_port	= htons(NFS_PORT),
		};

		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),
		mountdata->addr = (struct sockaddr *)&addr;
		mountdata->addrlen = sizeof(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++;
	}
	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;
	}

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

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

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

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>
	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",
3110ff80	89	__func__, path, fs_path);
54ceac45 DH	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	112
4ada29d5 BF	113	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	114	char page, char page2,
	115	const struct nfs4_fs_location *location)
	116	{
	117	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	118	char *mnt_path;
	119	unsigned int s = 0;
	120
	121	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	122	if (IS_ERR(mnt_path))
	123	return mnt;
	124	mountdata->mnt_path = mnt_path;
	125
	126	while (s < location->nservers) {
	127	struct sockaddr_in addr = {
	128	.sin_family = AF_INET,
	129	.sin_port = htons(NFS_PORT),
	130	};
	131
	132	if (location->servers[s].len <= 0 \|\|
	133	valid_ipaddr4(location->servers[s].data) < 0) {
	134	s++;
	135	continue;
	136	}
	137
	138	mountdata->hostname = location->servers[s].data;
	139	addr.sin_addr.s_addr = in_aton(mountdata->hostname),
	140	mountdata->addr = (struct sockaddr *)&addr;
	141	mountdata->addrlen = sizeof(addr);
	142
	143	snprintf(page, PAGE_SIZE, "%s:%s",
	144	mountdata->hostname,
	145	mountdata->mnt_path);
	146
	147	mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
	148	if (!IS_ERR(mnt))
	149	break;
	150	s++;
	151	}
	152	return mnt;
	153	}
	154
f7b422b1 DH	155	/**
	156	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
	157	* @mnt_parent - mountpoint of parent directory
	158	* @dentry - parent directory
3f43c666	159	* @locations - array of NFSv4 server location information
f7b422b1 DH	160	*
	161	*/
	162	static struct vfsmount nfs_follow_referral(const struct vfsmount mnt_parent,
	163	const struct dentry *dentry,
509de811	164	const struct nfs4_fs_locations *locations)
f7b422b1 DH	165	{
	166	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	167	struct nfs_clone_mount mountdata = {
	168	.sb = mnt_parent->mnt_sb,
	169	.dentry = dentry,
	170	.authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor,
	171	};
54ceac45	172	char page = NULL, page2 = NULL;
3f43c666	173	int loc, error;
f7b422b1 DH	174
	175	if (locations == NULL \|\| locations->nlocations <= 0)
	176	goto out;
	177
3110ff80	178	dprintk("%s: referral at %s/%s\n", __func__,
f7b422b1 DH	179	dentry->d_parent->d_name.name, dentry->d_name.name);
f7b422b1 DH	180
f7b422b1	181	page = (char *) __get_free_page(GFP_USER);
54ceac45	182	if (!page)
f7b422b1	183	goto out;
54ceac45	184
f7b422b1	185	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	186	if (!page2)
f7b422b1 DH	187	goto out;
f7b422b1 DH	188
54ceac45 DH	189	/* Ensure fs path is a prefix of current dentry path */
	190	error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2);
	191	if (error < 0) {
	192	mnt = ERR_PTR(error);
	193	goto out;
f7b422b1 DH	194	}
f7b422b1 DH	195
f7b422b1	196	loc = 0;
4ada29d5	197	while (loc < locations->nlocations) {
509de811	198	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	199
	200	if (location == NULL \|\| location->nservers <= 0 \|\|
	201	location->rootpath.ncomponents == 0) {
	202	loc++;
	203	continue;
	204	}
	205
4ada29d5 BF	206	mnt = try_location(&mountdata, page, page2, location);
	207	if (!IS_ERR(mnt))
	208	break;
f7b422b1 DH	209	loc++;
	210	}
	211
f7b422b1	212	out:
54ceac45 DH	213	free_page((unsigned long) page);
54ceac45 DH	214	free_page((unsigned long) page2);
3110ff80	215	dprintk("%s: done\n", __func__);
f7b422b1 DH	216	return mnt;
	217	}
	218
	219	/*
	220	* nfs_do_refmount - handle crossing a referral on server
	221	* @dentry - dentry of referral
	222	* @nd - nameidata info
	223	*
	224	*/
	225	struct vfsmount nfs_do_refmount(const struct vfsmount mnt_parent, struct dentry *dentry)
	226	{
54ceac45	227	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	228	struct dentry *parent;
	229	struct nfs4_fs_locations *fs_locations = NULL;
	230	struct page *page;
	231	int err;
	232
	233	/* BUG_ON(IS_ROOT(dentry)); */
3110ff80	234	dprintk("%s: enter\n", __func__);
f7b422b1 DH	235
	236	page = alloc_page(GFP_KERNEL);
	237	if (page == NULL)
	238	goto out;
	239
	240	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	241	if (fs_locations == NULL)
	242	goto out_free;
	243
	244	/* Get locations */
54ceac45 DH	245	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	246
f7b422b1	247	parent = dget_parent(dentry);
54ceac45	248	dprintk("%s: getting locations for %s/%s\n",
3110ff80	249	__func__, parent->d_name.name, dentry->d_name.name);
54ceac45	250
c228fd3a	251	err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page);
f7b422b1	252	dput(parent);
54ceac45 DH	253	if (err != 0 \|\|
54ceac45 DH	254	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	255	fs_locations->fs_path.ncomponents <= 0)
	256	goto out_free;
	257
	258	mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations);
	259	out_free:
	260	__free_page(page);
	261	kfree(fs_locations);
	262	out:
3110ff80	263	dprintk("%s: done\n", __func__);
f7b422b1 DH	264	return mnt;
f7b422b1 DH	265	}