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_next_one_bit(addr, size, offset) \
		ext2_find_next_bit(addr, size, offset)

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;
	struct kernel_lb_addr loc;

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

	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_add_free_space(struct super_block *sb, u16 partition, u32 cnt)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct logicalVolIntegrityDesc *lvid;

	if (!sbi->s_lvid_bh)
		return;

	lvid = (struct logicalVolIntegrityDesc *)sbi->s_lvid_bh->b_data;
	le32_add_cpu(&lvid->freeSpaceTable[partition], cnt);
	udf_updated_lvid(sb);
}

static void udf_bitmap_free_blocks(struct super_block *sb,
				   struct inode *inode,
				   struct udf_bitmap *bitmap,
				   struct kernel_lb_addr *bloc,
				   uint32_t offset,
				   uint32_t count)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct buffer_head *bh = NULL;
	struct udf_part_map *partmap;
	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);
	partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
	if (bloc->logicalBlockNum < 0 ||
	    (bloc->logicalBlockNum + count) >
		partmap->s_partition_len) {
		udf_debug("%d < %d || %d + %d > %d\n",
			  bloc->logicalBlockNum, 0, bloc->logicalBlockNum,
			  count, partmap->s_partition_len);
		goto error_return;
	}

	block = bloc->logicalBlockNum + offset +
		(sizeof(struct spaceBitmapDesc) << 3);

	do {
		overflow = 0;
		block_group = block >> (sb->s_blocksize_bits + 3);
		bit = block % (sb->s_blocksize << 3);

		/*
		* Check to see if we are freeing blocks across a group boundary.
		*/
		if (bit + count > (sb->s_blocksize << 3)) {
			overflow = bit + count - (sb->s_blocksize << 3);
			count -= overflow;
		}
		bitmap_nr = load_block_bitmap(sb, bitmap, block_group);
		if (bitmap_nr < 0)
			goto error_return;

		bh = bitmap->s_block_bitmap[bitmap_nr];
		for (i = 0; i < count; i++) {
			if (udf_set_bit(bit + i, bh->b_data)) {
				udf_debug("bit %ld already set\n", bit + i);
				udf_debug("byte=%2x\n",
					((char *)bh->b_data)[(bit + i) >> 3]);
			} else {
				if (inode)
					dquot_free_block(inode, 1);
				udf_add_free_space(sb, sbi->s_partition, 1);
			}
		}
		mark_buffer_dirty(bh);
		if (