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	key->nfsversion = clp->rpc_ops->version;
78	key->family = clp->cl_addr.ss_family;
79
80	memset(key, 0, len);
81
82	switch (clp->cl_addr.ss_family) {
83	case AF_INET:
84		key->port = sin->sin_port;
85		key->addr[0].ipv4_addr = sin->sin_addr;
86		len += sizeof(key->addr[0].ipv4_addr);
87		break;
88
89	case AF_INET6:
90		key->port = sin6->sin6_port;
91		key->addr[0].ipv6_addr = sin6->sin6_addr;
92		len += sizeof(key->addr[0].ipv6_addr);
93		break;
94
95	default:
96		printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
97		       clp->cl_addr.ss_family);
98		len = 0;
99		break;
100	}
101
102	return len;
103}
104
105/*
106 * Define the server object for FS-Cache.  This is used to describe a server
107 * object to fscache_acquire_cookie().  It is keyed by the NFS protocol and
108 * server address parameters.
109 */
110const struct fscache_cookie_def nfs_fscache_server_index_def = {
111	.name		= "NFS.server",
112	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
113	.get_key	= nfs_server_get_key,
114};
115
116/*
117 * Generate a key to describe a superblock key in the main NFS index
118 */
119static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
120				  void *buffer, uint16_t bufmax)
121{
122	const struct nfs_fscache_key *key;
123	const struct nfs_server *nfss = cookie_netfs_data;
124	uint16_t len;
125
126	key = nfss->fscache_key;
127	len = sizeof(key->key) + key->key.uniq_len;
128	if (len > bufmax) {
129		len = 0;
130	} else {
131		memcpy(buffer, &key->key, sizeof(key->key));
132		memcpy(buffer + sizeof(key->key),
133		       key->key.uniquifier, key->key.uniq_len);
134	}
135
136	return len;
137}
138
139/*
140 * Define the superblock object for FS-Cache.  This is used to describe a
141 * superblock object to fscache_acquire_cookie().  It is keyed by all the NFS
142 * parameters that might cause a separate superblock.
143 */
144const struct fscache_cookie_def nfs_fscache_super_index_def = {
145	.name		= "NFS.super",
146	.type 		= FSCACHE_COOKIE_TYPE_INDEX,
147	.get_key	= nfs_super_get_key,
148};
149
150/*
151 * Definition of the auxiliary data attached to NFS inode storage objects
152 * within the cache.
153 *
154 * The contents of this struct are recorded in the on-disk local cache in the
155 * auxiliary data attached to the data storage object backing an inode.  This
156 * permits coherency to be managed when a new inode binds to an already extant
157 * cache object.
158 */
159struct nfs_fscache_inode_auxdata {
160	struct timespec	mtime;
161	struct timespec	ctime;
162	loff_t		size;
163	u64		change_attr;
164};
165
166/*
167 * Generate a key to describe an NFS inode in an NFS server's index
168 */
169static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data,
170					  void *buffer, uint16_t bufmax)
171{
172	const struct nfs_inode *nfsi = cookie_netfs_data;
173	uint16_t nsize;
174
175	/* use the inode's NFS filehandle as the key */
176	nsize = nfsi->fh.size;
177	memcpy(buffer, nfsi->fh.data, nsize);
178	return nsize;
179}
180
181/*
182 * Get certain file attributes from the netfs data
183 * - This function can be absent for an index
184 * - Not permitted to return an error
185 * - The netfs data from the cookie being used as the source is presented
186 */
187static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data,
188				       uint64_t *size)
189{
190	const struct nfs_inode *nfsi = cookie_netfs_data;
191
192	*size = nfsi->vfs_inode.i_size;
193}
194
195/*
196 * Get the auxiliary data from netfs data
197 * - This function can be absent if the index carries no state data
198 * - Should store the auxiliary data in the buffer
199 * - Should return the amount of amount stored
200 * - Not permitted to return an error
201 * - The netfs data from the cookie being used as the source is presented
202 */
203static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data,
204					  void *buffer, uint16_t bufmax)
205{
206	struct nfs_fscache_inode_auxdata auxdata;
207	const struct nfs_inode *nfsi = cookie_netfs_data;
208
209	memset(&auxdata, 0, sizeof(auxdata));
210	auxdata.size = nfsi->vfs_inode.i_size;
211	auxdata.mtime = nfsi->vfs_inode.i_mtime;
212	auxdata.ctime = nfsi->vfs_inode.i_ctime;
213
214	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
215		auxdata.change_attr = nfsi->change_attr;
216
217	if (bufmax > sizeof(auxdata))
218		bufmax = sizeof(auxdata);
219
220	memcpy(buffer, &auxdata, bufmax);
221	return bufmax;
222}
223
224/*
225 * Consult the netfs about the state of an object
226 * - This function can be absent if the index carries no state data
227 * - The netfs data from the cookie being used as the target is
228 *   presented, as is the auxiliary data
229 */
230static
231enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
232						  const void *data,
233						  uint16_t datalen)
234{
235	struct nfs_fscache_inode_auxdata auxdata;
236	struct nfs_inode *nfsi = cookie_netfs_data;
237
238	if (datalen != sizeof(auxdata))
239		return FSCACHE_CHECKAUX_OBSOLETE;
240
241	memset(&auxdata, 0, sizeof(auxdata));
242	auxdata.size = nfsi->vfs_inode.i_size;
243	auxdata.mtime = nfsi->vfs_inode.i_mtime;
244	auxdata.ctime = nfsi->vfs_inode.i_ctime;
245
246	if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
247		auxdata.change_attr = nfsi->change_attr;
248
249	if (memcmp(data, &auxdata, datalen) != 0)
250		return FSCACHE_CHECKAUX_OBSOLETE;
251
252	return FSCACHE_CHECKAUX_OKAY;
253}
254
255/*
256 * Indication from FS-Cache that the cookie is no longer cached
257 * - This function is called when the backing store currently caching a cookie
258 *   is removed
259 * - The netfs should use this to clean up any markers indicating cached pages
260 * - This is mandatory for any object that may have data
261 */
262static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data)
263{
264	struct nfs_inode *nfsi = cookie_netfs_data;
265	struct pagevec pvec;
266	pgoff_t first;
267	int loop, nr_pages;
268
269	pagevec_init(&pvec, 0);
270	first = 0;
271
272	dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi);
273
274	for (;;) {
275		/* grab a bunch of pages to unmark */
276		nr_pages = pagevec_lookup(&pvec,
277					  nfsi->vfs_inode.i_mapping,
278					  first,
279					  PAGEVEC_SIZE - pagevec_count(&pvec));
280		if (!nr_pages)
281			break;
282
283		for (loop = 0; loop < nr_pages; loop++)
284			ClearPageFsCache(pvec.pages[loop]);
285
286		first = pvec.pages[nr_pages - 1]->index + 1;
287
288		pvec.nr = nr_pages;
289		pagevec_release(&pvec);
290		cond_resched();
291	}
292}
293
294/*
295 * Get an extra reference on a read context.
296 * - This function can be absent if the completion function doesn't require a
297 *   context.
298 * - The read context is passed back to NFS in the event that a data read on the
299 *   cache fails with EIO - in which case the server must be contacted to
300 *   retrieve the data, which requires the read context for security.
301 */
302static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
303{
304	get_nfs_open_context(context);
305}
306
307/*
308 * Release an extra reference on a read context.
309 * - This function can be absent if the completion function doesn't require a
310 *   context.
311 */
312static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
313{
314	if (context)
315		put_nfs_open_context(context);
316}
317
318/*
319 * Define the inode object for FS-Cache.  This is used to describe an inode
320 * object to fscache_acquire_cookie().  It is keyed by the NFS file handle for
321 * an inode.
322 *
323 * Coherency is managed by comparing the copies of i_size, i_mtime and i_ctime
324 * held in the cache auxiliary data for the data storage object with those in
325 * the inode struct in memory.
326 */
327const struct fscache_cookie_def nfs_fscache_inode_object_def = {
328	.name		= "NFS.fh",
329	.type		= FSCACHE_COOKIE_TYPE_DATAFILE,
330	.get_key	= nfs_fscache_inode_get_key,
331	.get_attr	= nfs_fscache_inode_get_attr,
332	.get_aux	= nfs_fscache_inode_get_aux,
333	.check_aux	= nfs_fscache_inode_check_aux,
334	.now_uncached	= nfs_fscache_inode_now_uncached,
335	.get_context	= nfs_fh_get_context,
336	.put_context	= nfs_fh_put_context,
337};
338