fs/zfs/dev.c

   1 /*
   2  *
   3  *      based on code of fs/reiserfs/dev.c by
   4  *
   5  *      (C) Copyright 2003 - 2004
   6  *      Sysgo AG, <www.elinos.com>, Pavel Bartusek <pba@sysgo.com>
   7  *
   8  *      This program is free software; you can redistribute it and/or modify
   9  *      it under the terms of the GNU General Public License as published by
  10  *      the Free Software Foundation; either version 2 of the License, or
  11  *      (at your option) any later version.
  12  *
  13  *      This program is distributed in the hope that it will be useful,
  14  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *      GNU General Public License for more details.
  17  *
  18  *      You should have received a copy of the GNU General Public License
  19  *      along with this program; if not, write to the Free Software
  20  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21  */
  22
  23
  24 #include <common.h>
  25 #include <config.h>
  26 #include <zfs_common.h>
  27
  28 static block_dev_desc_t *zfs_block_dev_desc;
  29 static disk_partition_t part_info;
  30
  31 int zfs_set_blk_dev(block_dev_desc_t *rbdd, int part)
  32 {
  33         zfs_block_dev_desc = rbdd;
  34
  35         if (part == 0) {
  36                 /* disk doesn't use partition table */
  37                 part_info.start = 0;
  38                 part_info.size = rbdd->lba;
  39                 part_info.blksz = rbdd->blksz;
  40         } else {
  41                 if (get_partition_info(zfs_block_dev_desc, part, &part_info))
  42                         return 0;
  43         }
  44
  45         return part_info.size;
  46 }
  47
  48 /* err */
  49 int zfs_devread(int sector, int byte_offset, int byte_len, char *buf)
  50 {
  51         short sec_buffer[SECTOR_SIZE/sizeof(short)];
  52         char *sec_buf = (char *)sec_buffer;
  53         unsigned block_len;
  54
  55         /*
  56          *      Check partition boundaries
  57          */
  58         if ((sector < 0) ||
  59                 ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS)) >=
  60                  part_info.size)) {
  61                 /*              errnum = ERR_OUTSIDE_PART; */
  62                 printf(" ** zfs_devread() read outside partition sector %d\n", sector);
  63                 return 1;
  64         }
  65
  66         /*
  67          *      Get the read to the beginning of a partition.
  68          */
  69         sector += byte_offset >> SECTOR_BITS;
  70         byte_offset &= SECTOR_SIZE - 1;
  71
  72         debug(" <%d, %d, %d>\n", sector, byte_offset, byte_len);
  73
  74         if (zfs_block_dev_desc == NULL) {
  75                 printf("** Invalid Block Device Descriptor (NULL)\n");
  76                 return 1;
  77         }
  78
  79         if (byte_offset != 0) {
  80                 /* read first part which isn't aligned with start of sector */
  81                 if (zfs_block_dev_desc->block_read(zfs_block_dev_desc->dev,
  82                                                                                    part_info.start + sector, 1,
  83                                                                                    (unsigned long *) sec_buf) != 1) {
  84                         printf(" ** zfs_devread() read error **\n");
  85                         return 1;
  86                 }
  87                 memcpy(buf, sec_buf + byte_offset,
  88                            min(SECTOR_SIZE - byte_offset, byte_len));
  89                 buf += min(SECTOR_SIZE - byte_offset, byte_len);
  90                 byte_len -= min(SECTOR_SIZE - byte_offset, byte_len);
  91                 sector++;
  92         }
  93
  94         if (byte_len == 0)
  95                 return 0;
  96
  97         /*      read sector aligned part */
  98         block_len = byte_len & ~(SECTOR_SIZE - 1);
  99
 100         if (block_len == 0) {
 101                 u8 p[SECTOR_SIZE];
 102
 103                 block_len = SECTOR_SIZE;
 104                 zfs_block_dev_desc->block_read(zfs_block_dev_desc->dev,
 105                                                                            part_info.start + sector,
 106                                                                            1, (unsigned long *)p);
 107                 memcpy(buf, p, byte_len);
 108                 return 0;
 109         }
 110
 111         if (zfs_block_dev_desc->block_read(zfs_block_dev_desc->dev,
 112                                                                            part_info.start + sector,
 113                                                                            block_len / SECTOR_SIZE,
 114                                                                            (unsigned long *) buf) !=
 115                 block_len / SECTOR_SIZE) {
 116                 printf(" ** zfs_devread() read error - block\n");
 117                 return 1;
 118         }
 119
 120         block_len = byte_len & ~(SECTOR_SIZE - 1);
 121         buf += block_len;
 122         byte_len -= block_len;
 123         sector += block_len / SECTOR_SIZE;
 124
 125         if (byte_len != 0) {
 126                 /* read rest of data which are not in whole sector */
 127                 if (zfs_block_dev_desc->
 128                         block_read(zfs_block_dev_desc->dev,
 129                                            part_info.start + sector, 1,
 130                                            (unsigned long *) sec_buf) != 1) {
 131                         printf(" ** zfs_devread() read error - last part\n");
 132                         return 1;
 133                 }
 134                 memcpy(buf, sec_buf, byte_len);
 135         }
 136         return 0;
 137 }