path: root/fs/udf/balloc.c

/*
 * balloc.c
 *
 * PURPOSE
 *	Block allocation handling routines for the OSTA-UDF(tm) filesystem.
 *
 * COPYRIGHT
 *	This file is distributed under the terms of the GNU General Public
 *	License (GPL). Copies of the GPL can be obtained from:
 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
 *	Each contributing author retains all rights to their own work.
 *
 *  (C) 1999-2001 Ben Fennema
 *  (C) 1999 Stelias Computing Inc
 *
 * HISTORY
 *
 *  02/24/99 blf  Created.
 *
 */

#include "udfdecl.h"

#include <linux/quotaops.h>
#include <linux/buffer_head.h>
#include <linux/bitops.h>

#include "udf_i.h"
#include "udf_sb.h"

#define udf_clear_bit(nr,addr) ext2_clear_bit(nr,addr)
#define udf_set_bit(nr,addr) ext2_set_bit(nr,addr)
#define udf_test_bit(nr, addr) ext2_test_bit(nr, addr)
#define udf_find_first_one_bit(addr, size) find_first_one_bit(addr, size)
#define udf_find_next_one_bit(addr, size, offset) find_next_one_bit(addr, size, offset)

#define leBPL_to_cpup(x) leNUM_to_cpup(BITS_PER_LONG, x)
#define leNUM_to_cpup(x,y) xleNUM_to_cpup(x,y)
#define xleNUM_to_cpup(x,y) (le ## x ## _to_cpup(y))
#define uintBPL_t uint(BITS_PER_LONG)
#define uint(x) xuint(x)
#define xuint(x) __le ## x

static inline int find_next_one_bit (void * addr, int size, int offset)
{
	uintBPL_t * p = ((uintBPL_t *) addr) + (offset / BITS_PER_LONG);
	int result = offset & ~(BITS_PER_LONG-1);
	unsigned long tmp;

	if (offset >= size)
		return size;
	size -= result;
	offset &= (BITS_PER_LONG-1);
	if (offset)
	{
		tmp = leBPL_to_cpup(p++);
		tmp &= ~0UL << offset;
		if (size < BITS_PER_LONG)
			goto found_first;
		if (tmp)
			goto found_middle;
		size -= BITS_PER_LONG;
		result += BITS_PER_LONG;
	}
	while (size & ~(BITS_PER_LONG-1))
	{
		if ((tmp = leBPL_to_cpup(p++)))
			goto found_middle;
		result += BITS_PER_LONG;
		size -= BITS_PER_LONG;
	}
	if (!size)
		return result;
	tmp = leBPL_to_cpup(p);
found_first:
	tmp &= ~0UL >> (BITS_PER_LONG-size);
found_middle:
	return result + ffz(~tmp);
}

#define find_first_one_bit(addr, size)\
	find_next_one_bit((addr), (size), 0)

static int read_block_bitmap(struct super_block * sb,
	struct udf_bitmap *bitmap, unsigned int block, unsigned long bitmap_nr)
{
	struct buffer_head *bh = NULL;
	int retval = 0;
	kernel_lb_addr loc;

	loc.logicalBlockNum = bitmap->s_extPosition;
	loc.partitionReferenceNum = UDF_SB_PARTITION(sb);

	bh = udf_tread(sb, udf_get_lb_pblock(sb, loc, block));
	if (!bh)
	{
		retval = -EIO;
	}
	bitmap->s_block_bitmap[bitmap_nr] = bh;
	return retval;
}

static int __load_block_bitmap(struct super_block * sb,
	struct udf_bitmap *bitmap, unsigned int block_group)
{
	int retval = 0;
	int nr_groups = bitmap->s_nr_groups;

	if (block_group >= nr_groups)
	{
		udf_debug("block_group (%d) > nr_groups (%d)\n", block_group, nr_groups);
	}

	if (bitmap->s_block_bitmap[block_group])
		return block_group;
	else
	{
		retval = read_block_bitmap(sb, bitmap, block_group, block_group);
		if (retval < 0)
			return retval;
		return block_group;
	}
}

static inline int load_block_bitmap(struct super_block * sb,
	struct udf_bitmap *bitmap, unsigned int block_group)
{
	int slot;

	slot = __load_block_bitmap(sb, bitmap, block_group);

	if (slot < 0)
		return slot;

	if (!bitmap->s_block_bitmap[slot])
		return -EIO;

	return slot;
}

static void udf_bitmap_free_blocks(struct super_block * sb,
	struct inode * inode,
	struct udf_bitmap *bitmap,
	kernel_lb_addr bloc, uint32_t offset, uint32_t count)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct buffer_head * bh = NULL;
	unsigned long block;
	unsigned long block_group;
	unsigned long bit;
	unsigned long i;
	int bitmap_nr;
	unsigned long overflow;

	mutex_lock(&sbi->s_alloc_mutex);
	if (bloc.logicalBlockNum < 0 ||
		(bloc.logicalBlockNum + count) > UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum))
	{
		udf_debug("%d < %d || %d + %d > %d\n",
			bloc.logicalBlockNum, 0, bloc.logicalBlockNum, count,
			UDF_SB_PARTLEN(sb, bloc.partitionReferenceNum));
		goto error_return;