summaryrefslogtreecommitdiffstats
path: root/fs/nfs/nfs4namespace.c
blob: faed9bcba50fb0121d6c266a4cd94e63d01b7169 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 * linux/fs/nfs/nfs4namespace.c
 *
 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
 *
 * NFSv4 namespace
 */

#include <linux/config.h>

#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"

#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);
}


/**
 * 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, *page2;
	char *path, *fs_path;
	char *devname;
	int loc, s;

	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);

	/* Ensure fs path is a prefix of current dentry path */
	page = (char *) __get_free_page(GFP_USER);
	if (page == NULL)
		goto out;
	page2 = (char *) __get_free_page(GFP_USER);
	if (page2 == NULL)
		goto out;

	path = nfs4_path(dentry, page, PAGE_SIZE);
	if (IS_ERR(path))
		goto out_free;

	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	if (IS_ERR(fs_path))
		goto out_free;

	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
		dprintk("%s: path %s does not begin with fsroot %s\n", __FUNCTION__, path, fs_path);
		goto out_free;
	}

	devname = nfs_devname(mnt_parent, dentry, page, PAGE_SIZE);
	if (IS_ERR(devname)) {
		mnt = (struct vfsmount *)devname;
		goto out_free;
	}

	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;

			mnt = vfs_kern_mount(&nfs_referral_nfs4_fs_type, 0, devname, &mountdata);
			if (!IS_ERR(mnt)) {
				break;
			}
			s++;
		}
		loc++;
	}

out_free:
	free_page((unsigned long)page);
	free_page((unsigned long)page2);
out:
	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(-ENOENT);
	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 */
	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, 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;
}