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 */
30 struct fscache_netfs nfs_fscache_netfs = {
31 .name = "nfs",
32 .version = 0,
33 };
34
35 /*
36 * Register NFS for caching
37 */
nfs_fscache_register(void)38 int nfs_fscache_register(void)
39 {
40 return fscache_register_netfs(&nfs_fscache_netfs);
41 }
42
43 /*
44 * Unregister NFS for caching
45 */
nfs_fscache_unregister(void)46 void 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 */
54 struct 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 */
nfs_server_get_key(const void * cookie_netfs_data,void * buffer,uint16_t bufmax)68 static 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 */
109 const 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 */
nfs_super_get_key(const void * cookie_netfs_data,void * buffer,uint16_t bufmax)118 static 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 */
143 const 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 */
158 struct 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 */
nfs_fscache_inode_get_key(const void * cookie_netfs_data,void * buffer,uint16_t bufmax)168 static 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 */
nfs_fscache_inode_get_attr(const void * cookie_netfs_data,uint64_t * size)186 static 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 */
nfs_fscache_inode_get_aux(const void * cookie_netfs_data,void * buffer,uint16_t bufmax)202 static 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 */
229 static
nfs_fscache_inode_check_aux(void * cookie_netfs_data,const void * data,uint16_t datalen)230 enum 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 */
nfs_fscache_inode_now_uncached(void * cookie_netfs_data)261 static 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 */
nfs_fh_get_context(void * cookie_netfs_data,void * context)301 static 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 */
nfs_fh_put_context(void * cookie_netfs_data,void * context)311 static 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 */
326 const 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