fs/nfs/fscache-index.c

   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  */
  38 int nfs_fscache_register(void)
  39 {
  40         return fscache_register_netfs(&nfs_fscache_netfs);
  41 }
  42
  43 /*
  44  * Unregister NFS for caching
  45  */
  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  */
  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         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  */
 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,
 114 };
 115
 116 /*
 117  * Generate a key to describe a superblock key in the main NFS index
 118  */
 119 static 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  */
 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,
 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  */
 159 struct 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  */
 169 static 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  */
 187 static 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  */
 203 static 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  */
 230 static
 231 enum 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  */
 262 static 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  */
 302 static 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  */
 312 static 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  */
 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,
 337 };