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 };