udf: Allow loading of VAT inode

[deliverable/linux.git] / fs / udf / partition.c

/*
 * partition.c
 *
 * PURPOSE
 *      Partition 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) 1998-2001 Ben Fennema
 *
 * HISTORY
 *
 * 12/06/98 blf  Created file.
 *
 */

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

#include <linux/fs.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>

inline uint32_t udf_get_pblock(struct super_block *sb, uint32_t block,
			       uint16_t partition, uint32_t offset)
{
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct udf_part_map *map;
	if (partition >= sbi->s_partitions) {
		udf_debug("block=%d, partition=%d, offset=%d: "
			  "invalid partition\n", block, partition, offset);
		return 0xFFFFFFFF;
	}
	map = &sbi->s_partmaps[partition];
	if (map->s_partition_func)
		return map->s_partition_func(sb, block, partition, offset);
	else
		return map->s_partition_root + block + offset;
}

uint32_t udf_get_pblock_virt15(struct super_block *sb, uint32_t block,
			       uint16_t partition, uint32_t offset)
{
	struct buffer_head *bh = NULL;
	uint32_t newblock;
	uint32_t index;
	uint32_t loc;
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct udf_part_map *map;
	struct udf_virtual_data *vdata;
	struct udf_inode_info *iinfo;

	map = &sbi->s_partmaps[partition];
	vdata = &map->s_type_specific.s_virtual;
	index = (sb->s_blocksize - vdata->s_start_offset) / sizeof(uint32_t);

	if (block > vdata->s_num_entries) {
		udf_debug("Trying to access block beyond end of VAT "
			  "(%d max %d)\n", block, vdata->s_num_entries);
		return 0xFFFFFFFF;
	}

	if (block >= index) {
		block -= index;
		newblock = 1 + (block / (sb->s_blocksize / sizeof(uint32_t)));
		index = block % (sb->s_blocksize / sizeof(uint32_t));
	} else {
		newblock = 0;
		index = vdata->s_start_offset / sizeof(uint32_t) + block;
	}

	loc = udf_block_map(sbi->s_vat_inode, newblock);

	bh = sb_bread(sb, loc);
	if (!bh) {
		udf_debug("get_pblock(UDF_VIRTUAL_MAP:%p,%d,%d) VAT: %d[%d]\n",
			  sb, block, partition, loc, index);
		return 0xFFFFFFFF;
	}

	loc = le32_to_cpu(((__le32 *)bh->b_data)[index]);

	brelse(bh);

	iinfo = UDF_I(sbi->s_vat_inode);
	if (iinfo->i_location.partitionReferenceNum == partition) {
		udf_debug("recursive call to udf_get_pblock!\n");
		return 0xFFFFFFFF;
	}

	return udf_get_pblock(sb, loc,
			      iinfo->i_location.partitionReferenceNum,
			      offset);
}

inline uint32_t udf_get_pblock_virt20(struct super_block *sb, uint32_t block,
				      uint16_t partition, uint32_t offset)
{
	return udf_get_pblock_virt15(sb, block, partition, offset);
}

uint32_t udf_get_pblock_spar15(struct super_block *sb, uint32_t block,
			       uint16_t partition, uint32_t offset)
{
	int i;
	struct sparingTable *st = NULL;
	struct udf_sb_info *sbi = UDF_SB(sb);
	struct udf_part_map *map;
	uint32_t packet;
	struct udf_sparing_data *sdata;

	map = &sbi->s_partmaps[partition];
	sdata = &map->s_type_specific.s_sparing;
	packet = (block + offset) & ~(sdata->s_packet_len - 1);

	for (i = 0; i < 4; i++) {
		if (sdata->s_spar_map[i] != NULL) {
			st = (struct sparingTable *)
					sdata->s_spar_map[i]->b_data;
			break;
		}
	}

	if (st) {
		for (i = 0; i < le16_to_cpu(st->reallocationTableLen); i++) {
			struct sparingEntry *entry = &st->mapEntry[i];
			u32 origLoc = le32_to_cpu(entry->origLocation);
			if (origLoc >= 0xFFFFFFF0)
				break;
			else if (origLoc == packet)
				return le32_to_cpu(entry->mappedLocation) +
					((block + offset) &
						(sdata->s_packet_len - 1));
			else if (origLoc > packet)
				break;
		}
	}

	return map->s_partition_root + block + offset;
}

int udf_relocate_blocks(struct super_block *sb, long old_block, long *new_block)
{
	struct udf_sparing_data *sdata;
	struct sparingTable *st = NULL;
	struct sparingEntry mapEntry;
	uint32_t packet;
	int i, j, k, l;
	struct udf_sb_info *sbi = UDF_SB(sb);
	u16 reallocationTableLen;
	struct buffer_head *bh;

	for (i = 0; i < sbi->s_partitions; i++) {
		struct udf_part_map *map = &sbi->s_partmaps[i];
		if (old_block > map->s_partition_root &&
		    old_block < map->s_partition_root + map->s_partition_len) {
			sdata = &map->s_type_specific.s_sparing;
			packet = (old_block - map->s_partition_root) &
						~(sdata->s_packet_len - 1);

			for (j = 0; j < 4; j++)
				if (sdata->s_spar_map[j] != NULL) {
					st = (struct sparingTable *)
						sdata->s_spar_map[j]->b_data;
					break;
				}

			if (!st)
				return 1;

			reallocationTableLen =
					le16_to_cpu(st->reallocationTableLen);
			for (k = 0; k < reallocationTableLen; k++) {
				struct sparingEntry *entry = &st->mapEntry[k];
				u32 origLoc = le32_to_cpu(entry->origLocation);

				if (origLoc == 0xFFFFFFFF) {
					for (; j < 4; j++) {
						int len;
						bh = sdata->s_spar_map[j];
						if (!bh)
							continue;

						st = (struct sparingTable *)
								bh->b_data;
						entry->origLocation =
							cpu_to_le32(packet);
						len =
						  sizeof(struct sparingTable) +
						  reallocationTableLen *
						  sizeof(struct sparingEntry);
						udf_update_tag((char *)st, len);
						mark_buffer_dirty(bh);
					}
					*new_block = le32_to_cpu(
							entry->mappedLocation) +
						     ((old_block -
							map->s_partition_root) &
						     (sdata->s_packet_len - 1));
					return 0;
				} else if (origLoc == packet) {
					*new_block = le32_to_cpu(
							entry->mappedLocation) +
						     ((old_block -
							map->s_partition_root) &
						     (sdata->s_packet_len - 1));
					return 0;
				} else if (origLoc > packet)
					break;
			}

			for (l = k; l < reallocationTableLen; l++) {
				struct sparingEntry *entry = &st->mapEntry[l];
				u32 origLoc = le32_to_cpu(entry->origLocation);

				if (origLoc != 0xFFFFFFFF)
					continue;

				for (; j < 4; j++) {
					bh = sdata->s_spar_map[j];
					if (!bh)
						continue;

					st = (struct sparingTable *)bh->b_data;
					mapEntry = st->mapEntry[l];
					mapEntry.origLocation =
							cpu_to_le32(packet);
					memmove(&st->mapEntry[k + 1],
						&st->mapEntry[k],
						(l - k) *
						sizeof(struct sparingEntry));
					st->mapEntry[k] = mapEntry;
					udf_update_tag((char *)st,
						sizeof(struct sparingTable) +
						reallocationTableLen *
						sizeof(struct sparingEntry));
					mark_buffer_dirty(bh);
				}
				*new_block =
					le32_to_cpu(
					      st->mapEntry[k].mappedLocation) +
					((old_block - map->s_partition_root) &
					 (sdata->s_packet_len - 1));
				return 0;
			}

			return 1;
		} /* if old_block */
	}

	if (i == sbi->s_partitions) {
		/* outside of partitions */
		/* for now, fail =) */
		return 1;
	}

	return 0;
}