fs/reiserfs/dev.c

   1 /*
   2  *  (C) Copyright 2003 - 2004
   3  *  Sysgo AG, <www.elinos.com>, Pavel Bartusek <pba@sysgo.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20
  21 #include <common.h>
  22 #include <config.h>
  23 #include <reiserfs.h>
  24
  25 #include "reiserfs_private.h"
  26
  27 static block_dev_desc_t *reiserfs_block_dev_desc;
  28 static disk_partition_t *part_info;
  29
  30
  31 void reiserfs_set_blk_dev(block_dev_desc_t *rbdd, disk_partition_t *info)
  32 {
  33         reiserfs_block_dev_desc = rbdd;
  34         part_info = info;
  35 }
  36
  37
  38 int reiserfs_devread (int sector, int byte_offset, int byte_len, char *buf)
  39 {
  40         char sec_buf[SECTOR_SIZE];
  41         unsigned block_len;
  42 /*
  43         unsigned len = byte_len;
  44         u8 *start = buf;
  45 */
  46         /*
  47         *  Check partition boundaries
  48         */
  49         if (sector < 0
  50             || ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS))
  51             >= part_info->size)) {
  52 /*              errnum = ERR_OUTSIDE_PART; */
  53                 printf (" ** reiserfs_devread() read outside partition\n");
  54                 return 0;
  55         }
  56
  57         /*
  58          *  Get the read to the beginning of a partition.
  59          */
  60         sector += byte_offset >> SECTOR_BITS;
  61         byte_offset &= SECTOR_SIZE - 1;
  62
  63 #if defined(DEBUG)
  64         printf (" <%d, %d, %d> ", sector, byte_offset, byte_len);
  65 #endif
  66
  67
  68         if (reiserfs_block_dev_desc == NULL)
  69                 return 0;
  70
  71
  72         if (byte_offset != 0) {
  73                 /* read first part which isn't aligned with start of sector */
  74                 if (reiserfs_block_dev_desc->block_read(reiserfs_block_dev_desc->dev,
  75                     part_info->start + sector, 1,
  76                     (unsigned long *)sec_buf) != 1) {
  77                         printf (" ** reiserfs_devread() read error\n");
  78                         return 0;
  79                 }
  80                 memcpy(buf, sec_buf+byte_offset, min(SECTOR_SIZE-byte_offset, byte_len));
  81                 buf+=min(SECTOR_SIZE-byte_offset, byte_len);
  82                 byte_len-=min(SECTOR_SIZE-byte_offset, byte_len);
  83                 sector++;
  84         }
  85
  86         /* read sector aligned part */
  87         block_len = byte_len & ~(SECTOR_SIZE-1);
  88         if (reiserfs_block_dev_desc->block_read(reiserfs_block_dev_desc->dev,
  89             part_info->start + sector, block_len/SECTOR_SIZE,
  90             (unsigned long *)buf) != block_len/SECTOR_SIZE) {
  91                 printf (" ** reiserfs_devread() read error - block\n");
  92                 return 0;
  93         }
  94         buf+=block_len;
  95         byte_len-=block_len;
  96         sector+= block_len/SECTOR_SIZE;
  97
  98         if ( byte_len != 0 ) {
  99                 /* read rest of data which are not in whole sector */
 100                 if (reiserfs_block_dev_desc->block_read(reiserfs_block_dev_desc->dev,
 101                     part_info->start + sector, 1,
 102                     (unsigned long *)sec_buf) != 1) {
 103                         printf (" ** reiserfs_devread() read error - last part\n");
 104                         return 0;
 105                 }
 106                 memcpy(buf, sec_buf, byte_len);
 107         }
 108
 109         return 1;
 110 }