aboutsummaryrefslogtreecommitdiff
path: root/fs/nfs/fscache-index.c
blob: 3025fe8584a05ce24df0e5900d213679b12aa33e (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
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
/* NFS FS-Cache index structure definition
 *
 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_fs_sb.h>
#include <linux/in6.h>

#include "internal.h"
#include "fscache.h"

#define NFSDBG_FACILITY		NFSDBG_FSCACHE

/*
 * Define the NFS filesystem for FS-Cache.  Upon registration FS-Cache sticks
 * the cookie for the top-level index object for NFS into here.  The top-level
 * index can than have other cache objects inserted into it.
 */
struct fscache_netfs nfs_fscache_netfs = {
	.name		= "nfs",
	.version	= 0,
};

/*
 * Register NFS for caching
 */
int nfs_fscache_register(void)
{
	return fscache_register_netfs(&nfs_fscache_netfs);
}

/*
 * Unregister NFS for caching
 */
void nfs_fscache_unregister(void)
{
	fscache_unregister_netfs(&nfs_fscache_netfs);
}

/*
 * Layout of the key for an NFS server cache object.
 */
struct nfs_server_key {
	uint16_t	nfsversion;		/* NFS protocol version */
	uint16_t	family;			/* address family */
	uint16_t	port;			/* IP port */
	union {
		struct in_addr	ipv4_addr;	/* IPv4 address */
		struct in6_addr ipv6_addr;	/* IPv6 address */
	} addr[0];
};

/*
 * Generate a key to describe a server in the main NFS index
 * - We return the length of the key, or 0 if we can't generate one
 */
static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
				   void *buffer, uint16_t bufmax)
{
	const struct nfs_client *clp = cookie_netfs_data;
	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
	const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
	struct nfs_server_key *key = buffer;
	uint16_t len = sizeof(struct nfs_server_key);

	memset(key, 0, len);
	key->nfsversion = clp->rpc_ops->version;
	key->family = clp->cl_addr.ss_family;

	switch (clp->cl_addr.ss_family) {
	case AF_INET:
		key->port = sin->sin_port;
		key->addr[0].ipv4_addr = sin->sin_addr;
		len += sizeof(key->addr[0].ipv4_addr);
		break;

	case AF_INET6:
		key->port = sin6->sin6_port;
		key->addr[0].ipv6_addr = sin6->sin6_addr;
		len += sizeof(key->addr[0].ipv6_addr);
		break;

	default:
		printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
		       clp->cl_addr.ss_family);
		len = 0;
		break;
	}

	return len;
}

/*
 * Define the server object for FS-Cache.  This is used to describe a server
 * object to fscache_acquire_cookie().  It is keyed by the NFS protocol and
 * server address parameters.
 */
const struct fscache_cookie_def nfs_fscache_server_index_def = {
	.name		= "NFS.server",
	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
	.get_key	= nfs_server_get_key,
};

/*
 * Generate a key to describe a superblock key in the main NFS index
 */
static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
				  void *buffer, uint16_t bufmax)
{
	const struct nfs_fscache_key *key;
	const struct nfs_server *nfss = cookie_netfs_data;
	uint16_t len;

	key = nfss->fscache_key;
	len = sizeof(key->key) + key->key.uniq_len;
	if (len > bufmax) {
		len = 0;
	} else {
		memcpy(buffer, &key->key, sizeof(key->key));
		memcpy(buffer + sizeof(key->key),
		       key->key.uniquifier, key->key.uniq_len);
	}

	return len;
}

/*
 * Define the superblock object for FS-Cache.  This is used to describe a
 * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
 * parameters that might cause a separate superblock.
 */
const struct fscache_cookie_def nfs_fscache_super_index_def = {
	.name		= "NFS.super",
	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
	.get_key	= nfs_super_get_key,
};

/*
 * Definition of the auxiliary data attached to NFS inode storage objects
 * within the cache.
 *
 * The contents of this struct are recorded in the on-disk local cache in the
 * auxiliary data attached to the data storage object backing an inode.  This
 * permits coherency to be managed when a new inode binds to an already extant
 * cache object.
 */
struct nfs_fscache_inode_auxdata {
	struct timespec	mtime;
	struct timespec	ctime;
	loff_t		size;
	u64		change_attr;
};

/*
 * Generate a key to describe an NFS inode in an NFS server's index
 */
static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data,
					  void *buffer, uint16_t bufmax)
{
	const struct nfs_inode *nfsi = cookie_netfs_data;
	uint16_t nsize;

	/* use the inode's NFS filehandle as the key */
	nsize = nfsi->fh.size;
	memcpy(buffer, nfsi->fh.data, nsize);
	return nsize;
}

/*
 * Get certain file attributes from the netfs data
 * - This function can be absent for an index
 * - Not permitted to return an error
 * - The netfs data from the cookie being used as the source is presented
 */
static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data,
				       uint64_t *size)
{
	const struct nfs_inode *nfsi = cookie_netfs_data;

	*size = nfsi->vfs_inode.i_size;
}

/*
 * Get the auxiliary data from netfs data
 * - This function can be absent if the index carries no state data
 * - Should store the auxiliary data in the buffer
 * - Should return the amount of amount stored
 * - Not permitted to return an error
 * - The netfs data from the cookie being used as the source is presented
 */
static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data,
					  void *buffer, uint16_t bufmax)
{
	struct nfs_fscache_inode_auxdata auxdata;
	const struct nfs_inode *nfsi = cookie_netfs_data;

	memset(&auxdata, 0, sizeof(auxdata));
	auxdata.size = nfsi->vfs_inode.i_size;
	auxdata.mtime = nfsi->vfs_inode.i_mtime;
	auxdata.ctime = nfsi->vfs_inode.i_ctime;

	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
		auxdata.change_attr = nfsi->vfs_inode.i_version;

	if (bufmax > sizeof(auxdata))
		bufmax = sizeof(auxdata);

	memcpy(buffer, &auxdata, bufmax);
	return bufmax;
}

/*
 * Consult the netfs about the state of an object
 * - This function can be absent if the index carries no state data
 * - The netfs data from the cookie being used as the target is
 *   presented, as is the auxiliary data
 */
static
enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
						  const void *data,
						  uint16_t datalen)
{
	struct nfs_fscache_inode_auxdata auxdata;
	struct nfs_inode *nfsi = cookie_netfs_data;

	if (datalen != sizeof(auxdata))
		return FSCACHE_CHECKAUX_OBSOLETE;

	memset(&auxdata, 0, sizeof(auxdata));
	auxdata.size = nfsi->vfs_inode.i_size;
	auxdata.mtime = nfsi->vfs_inode.i_mtime;
	auxdata.ctime = nfsi->vfs_inode.i_ctime;

	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
		auxdata.change_attr = nfsi->vfs_inode.i_version;

	if (memcmp(data, &auxdata, datalen) != 0)
		return FSCACHE_CHECKAUX_OBSOLETE;

	return FSCACHE_CHECKAUX_OKAY;
}

/*
 * Get an extra reference on a read context.
 * - This function can be absent if the completion function doesn't require a
 *   context.
 * - The read context is passed back to NFS in the event that a data read on the
 *   cache fails with EIO - in which case the server must be contacted to
 *   retrieve the data, which requires the read context for security.
 */
static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
{
	get_nfs_open_context(context);
}

/*
 * Release an extra reference on a read context.
 * - This function can be absent if the completion function doesn't require a
 *   context.
 */
static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
{
	if (context)
		put_nfs_open_context(context);
}

/*
 * Define the inode object for FS-Cache.  This is used to describe an inode
 * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
 * an inode.
 *
 * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
 * held in the cache auxiliary data for the data storage object with those in
 * the inode struct in memory.
 */
const struct fscache_cookie_def nfs_fscache_inode_object_def = {
	.name		= "NFS.fh",
	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
	.get_key	= nfs_fscache_inode_get_key,
	.get_attr	= nfs_fscache_inode_get_attr,
	.get_aux	= nfs_fscache_inode_get_aux,
	.check_aux	= nfs_fscache_inode_check_aux,
	.get_context	= nfs_fh_get_context,
	.put_context	= nfs_fh_put_context,
};