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/*
* linux/fs/block_dev.c
*
* (C) 1991 Linus Torvalds
*/
#include <errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <asm/segment.h>
#include <asm/system.h>
int block_write(int dev, long * pos, char * buf, int count)
{
int block = *pos >> BLOCK_SIZE_BITS;
int offset = *pos & (BLOCK_SIZE-1);
int chars;
int written = 0;
struct buffer_head * bh;
register char * p;
while (count>0) {
chars = BLOCK_SIZE - offset;
if (chars > count)
chars=count;
if (chars == BLOCK_SIZE)
bh = getblk(dev,block);
else
bh = breada(dev,block,block+1,block+2,-1);
block++;
if (!bh)
return written?written:-EIO;
p = offset + bh->b_data;
offset = 0;
*pos += chars;
written += chars;
count -= chars;
while (chars-->0)
*(p++) = get_fs_byte(buf++);
bh->b_dirt = 1;
brelse(bh);
}
return written;
}
int block_read(int dev, unsigned long * pos, char * buf, int count)
{
int block = *pos >> BLOCK_SIZE_BITS;
int offset = *pos & (BLOCK_SIZE-1);
int chars;
int read = 0;
struct buffer_head * bh;
register char * p;
while (count>0) {
chars = BLOCK_SIZE-offset;
if (chars > count)
chars = count;
if (!(bh = breada(dev,block,block+1,block+2,-1)))
return read?read:-EIO;
block++;
p = offset + bh->b_data;
offset = 0;
*pos += chars;
read += chars;
count -= chars;
while (chars-->0)
put_fs_byte(*(p++),buf++);
brelse(bh);
}
return read;
}
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