1/* NFS FS-Cache index structure definition
2 *
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#include <linux/init.h>
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/mm.h>
16#include <linux/nfs_fs.h>
17#include <linux/nfs_fs_sb.h>
18#include <linux/in6.h>
19
20#include "internal.h"
21#include "fscache.h"
22
23#define NFSDBG_FACILITY		NFSDBG_FSCACHE
24
25/*
26 * Define the NFS filesystem for FS-Cache.  Upon registration FS-Cache sticks
27 * the cookie for the top-level index object for NFS into here.  The top-level
28 * index can than have other cache objects inserted into it.
29 */
30struct fscache_netfs nfs_fscache_netfs = {
31	.name		= "nfs",
32	.version	= 0,
33};
34
35/*
36 * Register NFS for caching
37 */
38int nfs_fscache_register(void)
39{
40	return fscache_register_netfs(&nfs_fscache_netfs);
41}
42
43/*
44 * Unregister NFS for caching
45 */
46void nfs_fscache_unregister(void)
47{
48	fscache_unregister_netfs(&nfs_fscache_netfs);
49}
50
51/*
52 * Layout of the key for an NFS server cache object.
53 */
54struct nfs_server_key {
55	uint16_t	nfsversion;		/* NFS protocol version */
56	uint16_t	family;			/* address family */
57	uint16_t	port;			/* IP port */
58	union {
59		struct in_addr	ipv4_addr;	/* IPv4 address */
60		struct in6_addr ipv6_addr;	/* IPv6 address */
61	} addr[0];
62};
63
64/*
65 * Generate a key to describe a server in the main NFS index
66 * - We return the length of the key, or 0 if we can't generate one
67 */
68static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
69				   void *buffer, uint16_t bufmax)
70{
71	const struct nfs_client *clp = cookie_netfs_data;
72	const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *) &clp->cl_addr;
73	const struct sockaddr_in *sin = (struct sockaddr_in *) &clp->cl_addr;
74	struct nfs_server_key *key = buffer;
75	uint16_t len = sizeof(struct nfs_server_key);
76
77	memset(key, 0, len);
78	key->nfsversion = clp->rpc_ops->version;
79	key->family = clp->cl_addr.ss_family;
80
81	switch (clp->cl_addr.ss_family) {
82	case AF_INET:
83		key->port = sin->sin_port;
84		key->addr[0].ipv4_addr = sin->sin_addr;
85		len += sizeof(key->addr[0].ipv4_addr);
86		break;
87
88	case AF_INET6:
89		key->port = sin6->sin6_port;
90		key->addr[0].ipv6_addr = sin6->sin6_addr;
91		len += sizeof(key->addr[0].ipv6_addr);
92		break;
93
94	default:
95		printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
96		       clp->cl_addr.ss_family);
97		len = 0;
98		break;
99	}
100
101	return len;
102}
103
104/*
105 * Define the server object for FS-Cache.  This is used to describe a server
106 * object to fscache_acquire_cookie().  It is keyed by the NFS protocol and
107 * server address parameters.
108 */
109const struct fscache_cookie_def nfs_fscache_server_index_def = {
110	.name		= "NFS.server",
111	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
112	.get_key	= nfs_server_get_key,
113};
114
115/*
116 * Generate a key to describe a superblock key in the main NFS index
117 */
118static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
119				  void *buffer, uint16_t bufmax)
120{
121	const struct nfs_fscache_key *key;
122	const struct nfs_server *nfss = cookie_netfs_data;
123	uint16_t len;
124
125	key = nfss->fscache_key;
126	len = sizeof(key->key) + key->key.uniq_len;
127	if (len > bufmax) {
128		len = 0;
129	} else {
130		memcpy(buffer, &key->key, sizeof(key->key));
131		memcpy(buffer + sizeof(key->key),
132		       key->key.uniquifier, key->key.uniq_len);
133	}
134
135	return len;
136}
137
138/*
139 * Define the superblock object for FS-Cache.  This is used to describe a
140 * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
141 * parameters that might cause a separate superblock.
142 */
143const struct fscache_cookie_def nfs_fscache_super_index_def = {
144	.name		= "NFS.super",
145	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
146	.get_key	= nfs_super_get_key,
147};
148
149/*
150 * Definition of the auxiliary data attached to NFS inode storage objects
151 * within the cache.
152 *
153 * The contents of this struct are recorded in the on-disk local cache in the
154 * auxiliary data attached to the data storage object backing an inode.  This
155 * permits coherency to be managed when a new inode binds to an already extant
156 * cache object.
157 */
158struct nfs_fscache_inode_auxdata {
159	struct timespec	mtime;
160	struct timespec	ctime;
161	loff_t		size;
162	u64		change_attr;
163};
164
165/*
166 * Generate a key to describe an NFS inode in an NFS server's index
167 */
168static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data,
169					  void *buffer, uint16_t bufmax)
170{
171	const struct nfs_inode *nfsi = cookie_netfs_data;
172	uint16_t nsize;
173
174	/* use the inode's NFS filehandle as the key */
175	nsize = nfsi->fh.size;
176	memcpy(buffer, nfsi->fh.data, nsize);
177	return nsize;
178}
179
180/*
181 * Get certain file attributes from the netfs data
182 * - This function can be absent for an index
183 * - Not permitted to return an error
184 * - The netfs data from the cookie being used as the source is presented
185 */
186static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data,
187				       uint64_t *size)
188{
189	const struct nfs_inode *nfsi = cookie_netfs_data;
190
191	*size = nfsi->vfs_inode.i_size;
192}
193
194/*
195 * Get the auxiliary data from netfs data
196 * - This function can be absent if the index carries no state data
197 * - Should store the auxiliary data in the buffer
198 * - Should return the amount of amount stored
199 * - Not permitted to return an error
200 * - The netfs data from the cookie being used as the source is presented
201 */
202static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data,
203					  void *buffer, uint16_t bufmax)
204{
205	struct nfs_fscache_inode_auxdata auxdata;
206	const struct nfs_inode *nfsi = cookie_netfs_data;
207
208	memset(&auxdata, 0, sizeof(auxdata));
209	auxdata.size = nfsi->vfs_inode.i_size;
210	auxdata.mtime = nfsi->vfs_inode.i_mtime;
211	auxdata.ctime = nfsi->vfs_inode.i_ctime;
212
213	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
214		auxdata.change_attr = nfsi->vfs_inode.i_version;
215
216	if (bufmax > sizeof(auxdata))
217		bufmax = sizeof(auxdata);
218
219	memcpy(buffer, &auxdata, bufmax);
220	return bufmax;
221}
222
223/*
224 * Consult the netfs about the state of an object
225 * - This function can be absent if the index carries no state data
226 * - The netfs data from the cookie being used as the target is
227 *   presented, as is the auxiliary data
228 */
229static
230enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
231						  const void *data,
232						  uint16_t datalen)
233{
234	struct nfs_fscache_inode_auxdata auxdata;
235	struct nfs_inode *nfsi = cookie_netfs_data;
236
237	if (datalen != sizeof(auxdata))
238		return FSCACHE_CHECKAUX_OBSOLETE;
239
240	memset(&auxdata, 0, sizeof(auxdata));
241	auxdata.size = nfsi->vfs_inode.i_size;
242	auxdata.mtime = nfsi->vfs_inode.i_mtime;
243	auxdata.ctime = nfsi->vfs_inode.i_ctime;
244
245	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
246		auxdata.change_attr = nfsi->vfs_inode.i_version;
247
248	if (memcmp(data, &auxdata, datalen) != 0)
249		return FSCACHE_CHECKAUX_OBSOLETE;
250
251	return FSCACHE_CHECKAUX_OKAY;
252}
253
254/*
255 * Indication from FS-Cache that the cookie is no longer cached
256 * - This function is called when the backing store currently caching a cookie
257 *   is removed
258 * - The netfs should use this to clean up any markers indicating cached pages
259 * - This is mandatory for any object that may have data
260 */
261static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data)
262{
263	struct nfs_inode *nfsi = cookie_netfs_data;
264	struct pagevec pvec;
265	pgoff_t first;
266	int loop, nr_pages;
267
268	pagevec_init(&pvec, 0);
269	first = 0;
270
271	dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi);
272
273	for (;;) {
274		/* grab a bunch of pages to unmark */
275		nr_pages = pagevec_lookup(&pvec,
276					  nfsi->vfs_inode.i_mapping,
277					  first,
278					  PAGEVEC_SIZE - pagevec_count(&pvec));
279		if (!nr_pages)
280			break;
281
282		for (loop = 0; loop < nr_pages; loop++)
283			ClearPageFsCache(pvec.pages[loop]);
284
285		first = pvec.pages[nr_pages - 1]->index + 1;
286
287		pvec.nr = nr_pages;
288		pagevec_release(&pvec);
289		cond_resched();
290	}
291}
292
293/*
294 * Get an extra reference on a read context.
295 * - This function can be absent if the completion function doesn't require a
296 *   context.
297 * - The read context is passed back to NFS in the event that a data read on the
298 *   cache fails with EIO - in which case the server must be contacted to
299 *   retrieve the data, which requires the read context for security.
300 */
301static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
302{
303	get_nfs_open_context(context);
304}
305
306/*
307 * Release an extra reference on a read context.
308 * - This function can be absent if the completion function doesn't require a
309 *   context.
310 */
311static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
312{
313	if (context)
314		put_nfs_open_context(context);
315}
316
317/*
318 * Define the inode object for FS-Cache.  This is used to describe an inode
319 * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
320 * an inode.
321 *
322 * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
323 * held in the cache auxiliary data for the data storage object with those in
324 * the inode struct in memory.
325 */
326const struct fscache_cookie_def nfs_fscache_inode_object_def = {
327	.name		= "NFS.fh",
328	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
329	.get_key	= nfs_fscache_inode_get_key,
330	.get_attr	= nfs_fscache_inode_get_attr,
331	.get_aux	= nfs_fscache_inode_get_aux,
332	.check_aux	= nfs_fscache_inode_check_aux,
333	.now_uncached	= nfs_fscache_inode_now_uncached,
334	.get_context	= nfs_fh_get_context,
335	.put_context	= nfs_fh_put_context,
336};
337