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David Howells8ec442a2009-04-03 16:42:42 +01001/* 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}
David Howells14727282009-04-03 16:42:42 +010050
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};
David Howells08734042009-04-03 16:42:42 +0100115
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};
David Howells10329a52009-04-03 16:42:43 +0100149
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)
Trond Myklebusta9a4a872011-10-17 16:08:46 -0700215 auxdata.change_attr = nfsi->vfs_inode.i_version;
David Howells10329a52009-04-03 16:42:43 +0100216
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)
Trond Myklebusta9a4a872011-10-17 16:08:46 -0700247 auxdata.change_attr = nfsi->vfs_inode.i_version;
David Howells10329a52009-04-03 16:42:43 +0100248
249 if (memcmp(data, &auxdata, datalen) != 0)
250 return FSCACHE_CHECKAUX_OBSOLETE;
251
252 return FSCACHE_CHECKAUX_OKAY;
253}
254
255/*
David Howellsd5990642009-04-03 16:42:43 +0100256 * 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/*
David Howells1fcdf532009-04-03 16:42:44 +0100295 * 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/*
David Howells10329a52009-04-03 16:42:43 +0100319 * 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,
David Howellsd5990642009-04-03 16:42:43 +0100334 .now_uncached = nfs_fscache_inode_now_uncached,
David Howells1fcdf532009-04-03 16:42:44 +0100335 .get_context = nfs_fh_get_context,
336 .put_context = nfs_fh_put_context,
David Howells10329a52009-04-03 16:42:43 +0100337};