1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * linux/fs/befs/io.c
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2001 Will Dyson <will_dyson@pobox.com
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Based on portions of file.c and inode.c
8*4882a593Smuzhiyun * by Makoto Kato (m_kato@ga2.so-net.ne.jp)
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * Many thanks to Dominic Giampaolo, author of Practical File System
11*4882a593Smuzhiyun * Design with the Be File System, for such a helpful book.
12*4882a593Smuzhiyun *
13*4882a593Smuzhiyun */
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #include <linux/buffer_head.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #include "befs.h"
18*4882a593Smuzhiyun #include "io.h"
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun /*
21*4882a593Smuzhiyun * Converts befs notion of disk addr to a disk offset and uses
22*4882a593Smuzhiyun * linux kernel function sb_bread() to get the buffer containing
23*4882a593Smuzhiyun * the offset.
24*4882a593Smuzhiyun */
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun struct buffer_head *
befs_bread_iaddr(struct super_block * sb,befs_inode_addr iaddr)27*4882a593Smuzhiyun befs_bread_iaddr(struct super_block *sb, befs_inode_addr iaddr)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun struct buffer_head *bh;
30*4882a593Smuzhiyun befs_blocknr_t block;
31*4882a593Smuzhiyun struct befs_sb_info *befs_sb = BEFS_SB(sb);
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun befs_debug(sb, "---> Enter %s "
34*4882a593Smuzhiyun "[%u, %hu, %hu]", __func__, iaddr.allocation_group,
35*4882a593Smuzhiyun iaddr.start, iaddr.len);
36*4882a593Smuzhiyun
37*4882a593Smuzhiyun if (iaddr.allocation_group > befs_sb->num_ags) {
38*4882a593Smuzhiyun befs_error(sb, "BEFS: Invalid allocation group %u, max is %u",
39*4882a593Smuzhiyun iaddr.allocation_group, befs_sb->num_ags);
40*4882a593Smuzhiyun goto error;
41*4882a593Smuzhiyun }
42*4882a593Smuzhiyun
43*4882a593Smuzhiyun block = iaddr2blockno(sb, &iaddr);
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun befs_debug(sb, "%s: offset = %lu", __func__, (unsigned long)block);
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun bh = sb_bread(sb, block);
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun if (bh == NULL) {
50*4882a593Smuzhiyun befs_error(sb, "Failed to read block %lu",
51*4882a593Smuzhiyun (unsigned long)block);
52*4882a593Smuzhiyun goto error;
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun befs_debug(sb, "<--- %s", __func__);
56*4882a593Smuzhiyun return bh;
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun error:
59*4882a593Smuzhiyun befs_debug(sb, "<--- %s ERROR", __func__);
60*4882a593Smuzhiyun return NULL;
61*4882a593Smuzhiyun }
62