[net-next-2.6.git] / fs / qnx4 / bitmap.c

/*
 * QNX4 file system, Linux implementation.
 *
 * Version : 0.2.1
 *
 * Using parts of the xiafs filesystem.
 *
 * History :
 *
 * 28-05-1998 by Richard Frowijn : first release.
 * 20-06-1998 by Frank Denis : basic optimisations.
 * 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
 * 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
 */

#include <linux/buffer_head.h>
#include <linux/bitops.h>
#include "qnx4.h"

static void count_bits(register const char *bmPart, register int size,
		       int *const tf)
{
	char b;
	int tot = *tf;

	if (size > QNX4_BLOCK_SIZE) {
		size = QNX4_BLOCK_SIZE;
	}
	do {
		b = *bmPart++;
		tot += 8 - hweight8(b);
		size--;
	} while (size != 0);
	*tf = tot;
}

unsigned long qnx4_count_free_blocks(struct super_block *sb)
{
	int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
	int total = 0;
	int total_free = 0;
	int offset = 0;
	int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
	struct buffer_head *bh;

	while (total < size) {
		if ((bh = sb_bread(sb, start + offset)) == NULL) {
			printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
			break;
		}
		count_bits(bh->b_data, size - total, &total_free);
		brelse(bh);
		total += QNX4_BLOCK_SIZE;
		offset++;
	}

	return total_free;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* QNX4 file system, Linux implementation.
	3	*
	4	* Version : 0.2.1
	5	*
	6	* Using parts of the xiafs filesystem.
	7	*
	8	* History :
	9	*
	10	* 28-05-1998 by Richard Frowijn : first release.
	11	* 20-06-1998 by Frank Denis : basic optimisations.
	12	* 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
	13	* 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
	14	*/
	15
1da177e4 LT	16	#include <linux/buffer_head.h>
1da177e4 LT	17	#include <linux/bitops.h>
964f5369	18	#include "qnx4.h"
1da177e4	19
1da177e4 LT	20	static void count_bits(register const char *bmPart, register int size,
	21	int *const tf)
	22	{
	23	char b;
	24	int tot = *tf;
	25
	26	if (size > QNX4_BLOCK_SIZE) {
	27	size = QNX4_BLOCK_SIZE;
	28	}
	29	do {
	30	b = *bmPart++;
868d6481	31	tot += 8 - hweight8(b);
1da177e4 LT	32	size--;
	33	} while (size != 0);
	34	*tf = tot;
	35	}
	36
	37	unsigned long qnx4_count_free_blocks(struct super_block *sb)
	38	{
	39	int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
	40	int total = 0;
	41	int total_free = 0;
	42	int offset = 0;
	43	int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
	44	struct buffer_head *bh;
	45
	46	while (total < size) {
	47	if ((bh = sb_bread(sb, start + offset)) == NULL) {
891ddb95	48	printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
1da177e4 LT	49	break;
	50	}
	51	count_bits(bh->b_data, size - total, &total_free);
	52	brelse(bh);
	53	total += QNX4_BLOCK_SIZE;
	54	offset++;
	55	}
	56
	57	return total_free;
	58	}