/filesystems/unixfs/common/linux/linux.c

 1#include <sys/types.h>
 2#include <sys/uio.h>
 3#include <unistd.h>
 4#include <stdlib.h>
 5
 6#include "unixfs_internal.h"
 7#include "linux.h"
 8
 9int
10sb_bread_intobh(struct super_block* sb, off_t block, struct buffer_head* bh)
11{
12    if (pread(sb->s_bdev, bh->b_data, sb->s_blocksize,
13              block * (off_t)sb->s_blocksize) != sb->s_blocksize)
14        return EIO;
15
16    return 0;
17}
18
19void
20brelse(struct buffer_head* bh)
21{
22    if (bh && bh->b_flags.dynamic)
23        free((void*)bh);
24}
25
26struct buffer_head*
27sb_getblk(struct super_block* sb, sector_t block)
28{
29    struct buffer_head* bh = calloc(1, sizeof(struct buffer_head));
30    if (!bh) {
31        fprintf(stderr, "*** fatal error: cannot allocate buffer\n");
32        abort();
33    }
34    bh->b_flags.dynamic = 1;
35    bh->b_size = PAGE_SIZE;
36    bh->b_blocknr = block;
37    return bh;
38}
39
40struct buffer_head*
41sb_bread(struct super_block* sb, off_t block)
42{
43    struct buffer_head* bh = sb_getblk(sb, block);
44    if (bh && sb_bread_intobh(sb, block, bh) != 0) {
45        brelse(bh);
46        return NULL;
47    }
48    return bh;
49}