fs/cifs/cache.c

   1 /*
   2  *   fs/cifs/cache.c - CIFS filesystem cache index structure definitions
   3  *
   4  *   Copyright (c) 2010 Novell, Inc.
   5  *   Authors(s): Suresh Jayaraman (sjayaraman@suse.de>
   6  *
   7  *   This library is free software; you can redistribute it and/or modify
   8  *   it under the terms of the GNU Lesser General Public License as published
   9  *   by the Free Software Foundation; either version 2.1 of the License, or
  10  *   (at your option) any later version.
  11  *
  12  *   This library is distributed in the hope that it will be useful,
  13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  15  *   the GNU Lesser General Public License for more details.
  16  *
  17  *   You should have received a copy of the GNU Lesser General Public License
  18  *   along with this library; if not, write to the Free Software
  19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  20  */
  21 #include "fscache.h"
  22 #include "cifs_debug.h"
  23
  24 /*
  25  * CIFS filesystem definition for FS-Cache
  26  */
  27 struct fscache_netfs cifs_fscache_netfs = {
  28         .name = "cifs",
  29         .version = 0,
  30 };
  31
  32 /*
  33  * Register CIFS for caching with FS-Cache
  34  */
  35 int cifs_fscache_register(void)
  36 {
  37         return fscache_register_netfs(&cifs_fscache_netfs);
  38 }
  39
  40 /*
  41  * Unregister CIFS for caching
  42  */
  43 void cifs_fscache_unregister(void)
  44 {
  45         fscache_unregister_netfs(&cifs_fscache_netfs);
  46 }
  47
  48 /*
  49  * Server object for FS-Cache
  50  */
  51 const struct fscache_cookie_def cifs_fscache_server_index_def = {
  52         .name = "CIFS.server",
  53         .type = FSCACHE_COOKIE_TYPE_INDEX,
  54 };
  55
  56 /*
  57  * Auxiliary data attached to CIFS superblock within the cache
  58  */
  59 struct cifs_fscache_super_auxdata {
  60         u64     resource_id;            /* unique server resource id */
  61 };
  62
  63 char *extract_sharename(const char *treename)
  64 {
  65         const char *src;
  66         char *delim, *dst;
  67         int len;
  68
  69         /* skip double chars at the beginning */
  70         src = treename + 2;
  71
  72         /* share name is always preceded by '\\' now */
  73         delim = strchr(src, '\\');
  74         if (!delim)
  75                 return ERR_PTR(-EINVAL);
  76         delim++;
  77         len = strlen(delim);
  78
  79         /* caller has to free the memory */
  80         dst = kstrndup(delim, len, GFP_KERNEL);
  81         if (!dst)
  82                 return ERR_PTR(-ENOMEM);
  83
  84         return dst;
  85 }
  86
  87 static enum
  88 fscache_checkaux cifs_fscache_super_check_aux(void *cookie_netfs_data,
  89                                               const void *data,
  90                                               uint16_t datalen,
  91                                               loff_t object_size)
  92 {
  93         struct cifs_fscache_super_auxdata auxdata;
  94         const struct cifs_tcon *tcon = cookie_netfs_data;
  95
  96         if (datalen != sizeof(auxdata))
  97                 return FSCACHE_CHECKAUX_OBSOLETE;
  98
  99         memset(&auxdata, 0, sizeof(auxdata));
 100         auxdata.resource_id = tcon->resource_id;
 101
 102         if (memcmp(data, &auxdata, datalen) != 0)
 103                 return FSCACHE_CHECKAUX_OBSOLETE;
 104
 105         return FSCACHE_CHECKAUX_OKAY;
 106 }
 107
 108 /*
 109  * Superblock object for FS-Cache
 110  */
 111 const struct fscache_cookie_def cifs_fscache_super_index_def = {
 112         .name = "CIFS.super",
 113         .type = FSCACHE_COOKIE_TYPE_INDEX,
 114         .check_aux = cifs_fscache_super_check_aux,
 115 };
 116
 117 static enum
 118 fscache_checkaux cifs_fscache_inode_check_aux(void *cookie_netfs_data,
 119                                               const void *data,
 120                                               uint16_t datalen,
 121                                               loff_t object_size)
 122 {
 123         struct cifs_fscache_inode_auxdata auxdata;
 124         struct cifsInodeInfo *cifsi = cookie_netfs_data;
 125
 126         if (datalen != sizeof(auxdata))
 127                 return FSCACHE_CHECKAUX_OBSOLETE;
 128
 129         memset(&auxdata, 0, sizeof(auxdata));
 130         auxdata.eof = cifsi->server_eof;
 131         auxdata.last_write_time_sec = cifsi->vfs_inode.i_mtime.tv_sec;
 132         auxdata.last_change_time_sec = cifsi->vfs_inode.i_ctime.tv_sec;
 133         auxdata.last_write_time_nsec = cifsi->vfs_inode.i_mtime.tv_nsec;
 134         auxdata.last_change_time_nsec = cifsi->vfs_inode.i_ctime.tv_nsec;
 135
 136         if (memcmp(data, &auxdata, datalen) != 0)
 137                 return FSCACHE_CHECKAUX_OBSOLETE;
 138
 139         return FSCACHE_CHECKAUX_OKAY;
 140 }
 141
 142 const struct fscache_cookie_def cifs_fscache_inode_object_def = {
 143         .name           = "CIFS.uniqueid",
 144         .type           = FSCACHE_COOKIE_TYPE_DATAFILE,
 145         .check_aux      = cifs_fscache_inode_check_aux,
 146 };