fs/befs/io.c

   1 /*
   2  * linux/fs/befs/io.c
   3  *
   4  * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
   5  *
   6  * Based on portions of file.c and inode.c
   7  * by Makoto Kato (m_kato@ga2.so-net.ne.jp)
   8  *
   9  * Many thanks to Dominic Giampaolo, author of Practical File System
  10  * Design with the Be File System, for such a helpful book.
  11  *
  12  */
  13
  14 #include <linux/buffer_head.h>
  15
  16 #include "befs.h"
  17 #include "io.h"
  18
  19 /*
  20  * Converts befs notion of disk addr to a disk offset and uses
  21  * linux kernel function sb_bread() to get the buffer containing
  22  * the offset.
  23  */
  24
  25 struct buffer_head *
  26 befs_bread_iaddr(struct super_block *sb, befs_inode_addr iaddr)
  27 {
  28         struct buffer_head *bh;
  29         befs_blocknr_t block;
  30         struct befs_sb_info *befs_sb = BEFS_SB(sb);
  31
  32         befs_debug(sb, "---> Enter %s "
  33                    "[%u, %hu, %hu]", __func__, iaddr.allocation_group,
  34                    iaddr.start, iaddr.len);
  35
  36         if (iaddr.allocation_group > befs_sb->num_ags) {
  37                 befs_error(sb, "BEFS: Invalid allocation group %u, max is %u",
  38                            iaddr.allocation_group, befs_sb->num_ags);
  39                 goto error;
  40         }
  41
  42         block = iaddr2blockno(sb, &iaddr);
  43
  44         befs_debug(sb, "%s: offset = %lu", __func__, (unsigned long)block);
  45
  46         bh = sb_bread(sb, block);
  47
  48         if (bh == NULL) {
  49                 befs_error(sb, "Failed to read block %lu",
  50                            (unsigned long)block);
  51                 goto error;
  52         }
  53
  54         befs_debug(sb, "<--- %s", __func__);
  55         return bh;
  56
  57 error:
  58         befs_debug(sb, "<--- %s ERROR", __func__);
  59         return NULL;
  60 }