ACPI: pci_root: simplify list traversals
[linux-2.6/linux-acpi-2.6.git] / fs / nfs / fscache-index.c
blob5b1006480bc2dc3d7c07b371573c40d0ea74e4c3
1 /* NFS FS-Cache index structure definition
3 * Copyright (C) 2008 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
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>
20 #include "internal.h"
21 #include "fscache.h"
23 #define NFSDBG_FACILITY NFSDBG_FSCACHE
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.
30 struct fscache_netfs nfs_fscache_netfs = {
31 .name = "nfs",
32 .version = 0,
36 * Register NFS for caching
38 int nfs_fscache_register(void)
40 return fscache_register_netfs(&nfs_fscache_netfs);
44 * Unregister NFS for caching
46 void nfs_fscache_unregister(void)
48 fscache_unregister_netfs(&nfs_fscache_netfs);
52 * Layout of the key for an NFS server cache object.
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];
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
68 static uint16_t nfs_server_get_key(const void *cookie_netfs_data,
69 void *buffer, uint16_t bufmax)
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);
77 key->nfsversion = clp->rpc_ops->version;
78 key->family = clp->cl_addr.ss_family;
80 memset(key, 0, len);
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;
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;
95 default:
96 printk(KERN_WARNING "NFS: Unknown network family '%d'\n",
97 clp->cl_addr.ss_family);
98 len = 0;
99 break;
102 return len;
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.
110 const 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,
117 * Generate a key to describe a superblock key in the main NFS index
119 static uint16_t nfs_super_get_key(const void *cookie_netfs_data,
120 void *buffer, uint16_t bufmax)
122 const struct nfs_fscache_key *key;
123 const struct nfs_server *nfss = cookie_netfs_data;
124 uint16_t len;
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);
136 return len;
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.
144 const 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,
151 * Definition of the auxiliary data attached to NFS inode storage objects
152 * within the cache.
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.
159 struct nfs_fscache_inode_auxdata {
160 struct timespec mtime;
161 struct timespec ctime;
162 loff_t size;
163 u64 change_attr;
167 * Generate a key to describe an NFS inode in an NFS server's index
169 static uint16_t nfs_fscache_inode_get_key(const void *cookie_netfs_data,
170 void *buffer, uint16_t bufmax)
172 const struct nfs_inode *nfsi = cookie_netfs_data;
173 uint16_t nsize;
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;
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
187 static void nfs_fscache_inode_get_attr(const void *cookie_netfs_data,
188 uint64_t *size)
190 const struct nfs_inode *nfsi = cookie_netfs_data;
192 *size = nfsi->vfs_inode.i_size;
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
203 static uint16_t nfs_fscache_inode_get_aux(const void *cookie_netfs_data,
204 void *buffer, uint16_t bufmax)
206 struct nfs_fscache_inode_auxdata auxdata;
207 const struct nfs_inode *nfsi = cookie_netfs_data;
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;
214 if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
215 auxdata.change_attr = nfsi->change_attr;
217 if (bufmax > sizeof(auxdata))
218 bufmax = sizeof(auxdata);
220 memcpy(buffer, &auxdata, bufmax);
221 return bufmax;
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
230 static
231 enum fscache_checkaux nfs_fscache_inode_check_aux(void *cookie_netfs_data,
232 const void *data,
233 uint16_t datalen)
235 struct nfs_fscache_inode_auxdata auxdata;
236 struct nfs_inode *nfsi = cookie_netfs_data;
238 if (datalen != sizeof(auxdata))
239 return FSCACHE_CHECKAUX_OBSOLETE;
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;
246 if (NFS_SERVER(&nfsi->vfs_inode)->nfs_client->rpc_ops->version == 4)
247 auxdata.change_attr = nfsi->change_attr;
249 if (memcmp(data, &auxdata, datalen) != 0)
250 return FSCACHE_CHECKAUX_OBSOLETE;
252 return FSCACHE_CHECKAUX_OKAY;
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
262 static void nfs_fscache_inode_now_uncached(void *cookie_netfs_data)
264 struct nfs_inode *nfsi = cookie_netfs_data;
265 struct pagevec pvec;
266 pgoff_t first;
267 int loop, nr_pages;
269 pagevec_init(&pvec, 0);
270 first = 0;
272 dprintk("NFS: nfs_inode_now_uncached: nfs_inode 0x%p\n", nfsi);
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;
283 for (loop = 0; loop < nr_pages; loop++)
284 ClearPageFsCache(pvec.pages[loop]);
286 first = pvec.pages[nr_pages - 1]->index + 1;
288 pvec.nr = nr_pages;
289 pagevec_release(&pvec);
290 cond_resched();
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.
302 static void nfs_fh_get_context(void *cookie_netfs_data, void *context)
304 get_nfs_open_context(context);
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.
312 static void nfs_fh_put_context(void *cookie_netfs_data, void *context)
314 if (context)
315 put_nfs_open_context(context);
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.
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.
327 const 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,