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  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11
  12 #include <common.h>
  13 #include <config.h>
  14 #include <zfs_common.h>
  15
  16 static block_dev_desc_t *zfs_block_dev_desc;
  17 static disk_partition_t *part_info;
  18
  19 void zfs_set_blk_dev(block_dev_desc_t *rbdd, disk_partition_t *info)
  20 {
  21         zfs_block_dev_desc = rbdd;
  22         part_info = info;
  23 }
  24
  25 /* err */
  26 int zfs_devread(int sector, int byte_offset, int byte_len, char *buf)
  27 {
  28         short sec_buffer[SECTOR_SIZE/sizeof(short)];
  29         char *sec_buf = (char *)sec_buffer;
  30         unsigned block_len;
  31
  32         /*
  33          *      Check partition boundaries
  34          */
  35         if ((sector < 0) ||
  36                 ((sector + ((byte_offset + byte_len - 1) >> SECTOR_BITS)) >=
  37                  part_info->size)) {
  38                 /*              errnum = ERR_OUTSIDE_PART; */
  39                 printf(" ** zfs_devread() read outside partition sector %d\n", sector);
  40                 return 1;
  41         }
  42
  43         /*
  44          *      Get the read to the beginning of a partition.
  45          */
  46         sector += byte_offset >> SECTOR_BITS;
  47         byte_offset &= SECTOR_SIZE - 1;
  48
  49         debug(" <%d, %d, %d>\n", sector, byte_offset, byte_len);
  50
  51         if (zfs_block_dev_desc == NULL) {
  52                 printf("** Invalid Block Device Descriptor (NULL)\n");
  53                 return 1;
  54         }
  55
  56         if (byte_offset != 0) {
  57                 /* read first part which isn't aligned with start of sector */
  58                 if (zfs_block_dev_desc->block_read(zfs_block_dev_desc,
  59                                                    part_info->start + sector, 1,
  60                                                    (void *)sec_buf)
  61                     != 1) {
  62                         printf(" ** zfs_devread() read error **\n");
  63                         return 1;
  64                 }
  65                 memcpy(buf, sec_buf + byte_offset,
  66                            min(SECTOR_SIZE - byte_offset, byte_len));
  67                 buf += min(SECTOR_SIZE - byte_offset, byte_len);
  68                 byte_len -= min(SECTOR_SIZE - byte_offset, byte_len);
  69                 sector++;
  70         }
  71
  72         if (byte_len == 0)
  73                 return 0;
  74
  75         /*      read sector aligned part */
  76         block_len = byte_len & ~(SECTOR_SIZE - 1);
  77
  78         if (block_len == 0) {
  79                 u8 p[SECTOR_SIZE];
  80
  81                 block_len = SECTOR_SIZE;
  82                 zfs_block_dev_desc->block_read(zfs_block_dev_desc,
  83                                                part_info->start + sector,
  84                                                1, (void *)p);
  85                 memcpy(buf, p, byte_len);
  86                 return 0;
  87         }
  88
  89         if (zfs_block_dev_desc->block_read(zfs_block_dev_desc,
  90                                            part_info->start + sector,
  91                                            block_len / SECTOR_SIZE,
  92                                            (void *)buf)
  93             != block_len / SECTOR_SIZE) {
  94                 printf(" ** zfs_devread() read error - block\n");
  95                 return 1;
  96         }
  97
  98         block_len = byte_len & ~(SECTOR_SIZE - 1);
  99         buf += block_len;
 100         byte_len -= block_len;
 101         sector += block_len / SECTOR_SIZE;
 102
 103         if (byte_len != 0) {
 104                 /* read rest of data which are not in whole sector */
 105                 if (zfs_block_dev_desc->block_read(zfs_block_dev_desc,
 106                                                    part_info->start + sector,
 107                                                    1, (void *)sec_buf) != 1) {
 108                         printf(" ** zfs_devread() read error - last part\n");
 109                         return 1;
 110                 }
 111                 memcpy(buf, sec_buf, byte_len);
 112         }
 113         return 0;
 114 }