[linux-2.6-block.git] / fs / affs / bitmap.c

/*
 *  linux/fs/affs/bitmap.c
 *
 *  (c) 1996 Hans-Joachim Widmaier
 *
 *  bitmap.c contains the code that handles all bitmap related stuff -
 *  block allocation, deallocation, calculation of free space.
 */

#include "affs.h"

/* This is, of course, shamelessly stolen from fs/minix */

static const int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };

static u32
affs_count_free_bits(u32 blocksize, const void *data)
{
	const u32 *map;
	u32 free;
	u32 tmp;

	map = data;
	free = 0;
	for (blocksize /= 4; blocksize > 0; blocksize--) {
		tmp = *map++;
		while (tmp) {
			free += nibblemap[tmp & 0xf];
			tmp >>= 4;
		}
	}

	return free;
}

u32
affs_count_free_blocks(struct super_block *sb)
{
	struct affs_bm_info *bm;
	u32 free;
	int i;

	pr_debug("AFFS: count_free_blocks()\n");

	if (sb->s_flags & MS_RDONLY)
		return 0;

	mutex_lock(&AFFS_SB(sb)->s_bmlock);

	bm = AFFS_SB(sb)->s_bitmap;
	free = 0;
	for (i = AFFS_SB(sb)->s_bmap_count; i > 0; bm++, i--)
		free += bm->bm_free;

	mutex_unlock(&AFFS_SB(sb)->s_bmlock);

	return free;
}

void
affs_free_block(struct super_block *sb, u32 block)
{
	struct affs_sb_info *sbi = AFFS_SB(sb);
	struct affs_bm_info *bm;
	struct buffer_head *bh;
	u32 blk, bmap, bit, mask, tmp;
	__be32 *data;

	pr_debug("AFFS: free_block(%u)\n", block);

	if (block > sbi->s_partition_size)
		goto err_range;

	blk     = block - sbi->s_reserved;
	bmap    = blk / sbi->s_bmap_bits;
	bit     = blk % sbi->s_bmap_bits;
	bm      = &sbi->s_bitmap[bmap];

	mutex_lock(&sbi->s_bmlock);

	bh = sbi->s_bmap_bh;
	if (sbi->s_last_bmap != bmap) {
		affs_brelse(bh);
		bh = affs_bread(sb, bm->bm_key);
		if (!bh)
			goto err_bh_read;
		sbi->s_bmap_bh = bh;
		sbi->s_last_bmap = bmap;
	}

	mask = 1 << (bit & 31);
	data = (__be32 *)bh->b_data + bit / 32 + 1;

	/* mark block free */
	tmp = be32_to_cpu(*data);
	if (tmp & mask)
		goto err_free;
	*data = cpu_to_be32(tmp | mask);

	/* fix checksum */
	tmp = be32_to_cpu(*(__be32 *)bh->b_data);
	*(__be32 *)bh->b_data = cpu_to_be32(tmp - mask);

	mark_buffer_dirty(bh);
	sb->s_dirt = 1;
	bm->bm_free++;

	mutex_unlock(&sbi->s_bmlock);
	return;

err_free:
	affs_warning(sb,"affs_free_block","Trying to free block %u which is already free", block);
	mutex_unlock(&sbi->s_bmlock);
	return;

err_bh_read:
	affs_error(sb,"affs_free_block","Cannot read bitmap block %u", bm->bm_key);
	sbi->s_bmap_bh = NULL;
	sbi->s_last_bmap = ~0;
	mutex_unlock(&sbi->s_bmlock);
	return;

err_range:
	affs_error(sb, "affs_free_block","Block %u outside partition", block);
	return;
}

/*
 * Allocate a block in the given allocation zone.
 * Since we have to byte-swap the bitmap on little-endian
 * machines, this is rather expensive. Therefore we will
 * preallocate up to 16 blocks from the same word, if
 * possible. We are not doing preallocations in the
 * header zone, though.
 */

u32
affs_alloc_block(struct inode *inode, u32 goal)
{
	struct super_block *sb;
	struct affs_sb_info *sbi;
	struct affs_bm_info *bm;
	struct buffer_head *bh;
	__be32 *data, *enddata;
	u32 blk, bmap, bit, mask, mask2, tmp;
	int i;

	sb = inode->i_sb;
	sbi = AFFS_SB(sb);

	pr_debug("AFFS: balloc(inode=%lu,goal=%u): ", inode->i_ino, goal);

	if (AFFS_I(inode)->i_pa_cnt) {
		pr_debug("%d\n", AFFS_I(inode)->i_lastalloc+1);
		AFFS_I(inode)->i_pa_cnt--;
		return ++AFFS_I(inode)->i_lastalloc;
	}

	if (!goal || goal > sbi->s_partition_size) {
		if (goal)
			affs_warning(sb, "affs_balloc", "invalid goal %d", goal);
		//if (!AFFS_I(inode)->i_last_block)
		//	affs_warning(sb, "affs_balloc", "no last alloc block");
		goal = sbi->s_reserved;
	}

	blk = goal - sbi->s_reserved;
	bmap = blk / sbi->s_bmap_bits;
	bm = &sbi->s_bitmap[bmap];

	mutex_lock(&sbi->s_bmlock);

	if (bm->bm_free)
		goto find_bmap_bit;

find_bmap:
	/* search for the next bmap buffer with free bits */
	i = sbi->s_bmap_count;
	do {
		if (--i < 0)
			goto err_full;
		bmap++;
		bm++;
		if (bmap < sbi->s_bmap_count)
			continue;
		/* restart search at zero */
		bmap = 0;
		bm = sbi->s_bitmap;
	} while (!bm->bm_free);
	blk = bmap * sbi->s_bmap_bits;

find_bmap_bit:

	bh = sbi->s_bmap_bh;
	if (sbi->s_last_bmap != bmap) {
		affs_brelse(bh);
		bh = affs_bread(sb, bm->bm_key);
		if (!bh)
			goto err_bh_read;
		sbi->s_bmap_bh = bh;
		sbi->s_last_bmap = bmap;
	}

	/* find an unused block in this bitmap block */
	bit = blk % sbi->s_bmap_bits;
	data = (__be32 *)bh->b_data + bit / 32 + 1;
	enddata = (__be32 *)((u8 *)bh->b_data + sb->s_blocksize);
	mask = ~0UL << (bit & 31);
	blk &= ~31UL;

	tmp = be32_to_cpu(*data);
	if (tmp & mask)
		goto find_bit;

	/* scan the rest of the buffer */
	do {
		blk += 32;
		if (++data >= enddata)
			/* didn't find something, can only happen
			 * if scan didn't start at 0, try next bmap
			 */
			goto find_bmap;
	} while (!*data);
	tmp = be32_to_cpu(*data);
	mask = ~0;

find_bit:
	/* finally look for a free bit in the word */
	bit = ffs(tmp & mask) - 1;
	blk += bit + sbi->s_reserved;
	mask2 = mask = 1 << (bit & 31);
	AFFS_I(inode)->i_lastalloc = blk;

	/* prealloc as much as possible within this word */
	while ((mask2 <<= 1)) {
		if (!(tmp & mask2))
			break;
		AFFS_I(inode)->i_pa_cnt++;
		mask |= mask2;
	}
	bm->bm_free -= AFFS_I(inode)->i_pa_cnt + 1;

	*data = cpu_to_be32(tmp & ~mask);

	/* fix checksum */
	tmp = be32_to_cpu(*(__be32 *)bh->b_data);
	*(__be32 *)bh->b_data = cpu_to_be32(tmp + mask);

	mark_buffer_dirty(bh);
	sb->s_dirt = 1;

	mutex_unlock(&sbi->s_bmlock);

	pr_debug("%d\n", blk);
	return blk;

err_bh_read:
	affs_error(sb,"affs_read_block","Cannot read bitmap block %u", bm->bm_key);
	sbi->s_bmap_bh = NULL;
	sbi->s_last_bmap = ~0;
err_full:
	mutex_unlock(&sbi->s_bmlock);
	pr_debug("failed\n");
	return 0;
}

int affs_init_bitmap(struct super_block *sb, int *flags)
{
	struct affs_bm_info *bm;
	struct buffer_head *bmap_bh = NULL, *bh = NULL;
	__be32 *bmap_blk;
	u32 size, blk, end, offset, mask;
	int i, res = 0;
	struct affs_sb_info *sbi = AFFS_SB(sb);

	if (*flags & MS_RDONLY)
		return 0;

	if (!AFFS_ROOT_TAIL(sb, sbi->s_root_bh)->bm_flag) {
		printk(KERN_NOTICE "AFFS: Bitmap invalid - mounting %s read only\n",
			sb->s_id);
		*flags |= MS_RDONLY;
		return 0;
	}

	sbi->s_last_bmap = ~0;
	sbi->s_bmap_bh = NULL;
	sbi->s_bmap_bits = sb->s_blocksize * 8 - 32;
	sbi->s_bmap_count = (sbi->s_partition_size - sbi->s_reserved +
				 sbi->s_bmap_bits - 1) / sbi->s_bmap_bits;
	size = sbi->s_bmap_count * sizeof(*bm);
	bm = sbi->s_bitmap = kzalloc(size, GFP_KERNEL);
	if (!sbi->s_bitmap) {
		printk(KERN_ERR "AFFS: Bitmap allocation failed\n");
		return -ENOMEM;
	}

	bmap_blk = (__be32 *)sbi->s_root_bh->b_data;
	blk = sb->s_blocksize / 4 - 49;
	end = blk + 25;

	for (i = sbi->s_bmap_count; i > 0; bm++, i--) {
		affs_brelse(bh);

		bm->bm_key = be32_to_cpu(bmap_blk[blk]);
		bh = affs_bread(sb, bm->bm_key);
		if (!bh) {
			printk(KERN_ERR "AFFS: Cannot read bitmap\n");
			res = -EIO;
			goto out;
		}
		if (affs_checksum_block(sb, bh)) {
			printk(KERN_WARNING "AFFS: Bitmap %u invalid - mounting %s read only.\n",
			       bm->bm_key, sb->s_id);
			*flags |= MS_RDONLY;
			goto out;
		}
		pr_debug("AFFS: read bitmap block %d: %d\n", blk, bm->bm_key);
		bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);

		/* Don't try read the extension if this is the last block,
		 * but we also need the right bm pointer below
		 */
		if (++blk < end || i == 1)
			continue;
		if (bmap_bh)
			affs_brelse(bmap_bh);
		bmap_bh = affs_bread(sb, be32_to_cpu(bmap_blk[blk]));
		if (!bmap_bh) {
			printk(KERN_ERR "AFFS: Cannot read bitmap extension\n");
			res = -EIO;
			goto out;
		}
		bmap_blk = (__be32 *)bmap_bh->b_data;
		blk = 0;
		end = sb->s_blocksize / 4 - 1;
	}

	offset = (sbi->s_partition_size - sbi->s_reserved) % sbi->s_bmap_bits;
	mask = ~(0xFFFFFFFFU << (offset & 31));
	pr_debug("last word: %d %d %d\n", offset, offset / 32 + 1, mask);
	offset = offset / 32 + 1;

	if (mask) {
		u32 old, new;

		/* Mark unused bits in the last word as allocated */
		old = be32_to_cpu(((__be32 *)bh->b_data)[offset]);
		new = old & mask;
		//if (old != new) {
			((__be32 *)bh->b_data)[offset] = cpu_to_be32(new);
			/* fix checksum */
			//new -= old;
			//old = be32_to_cpu(*(__be32 *)bh->b_data);
			//*(__be32 *)bh->b_data = cpu_to_be32(old - new);
			//mark_buffer_dirty(bh);
		//}
		/* correct offset for the bitmap count below */
		//offset++;
	}
	while (++offset < sb->s_blocksize / 4)
		((__be32 *)bh->b_data)[offset] = 0;
	((__be32 *)bh->b_data)[0] = 0;
	((__be32 *)bh->b_data)[0] = cpu_to_be32(-affs_checksum_block(sb, bh));
	mark_buffer_dirty(bh);

	/* recalculate bitmap count for last block */
	bm--;
	bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);

out:
	affs_brelse(bh);
	affs_brelse(bmap_bh);
	return res;
}

void affs_free_bitmap(struct super_block *sb)
{
	struct affs_sb_info *sbi = AFFS_SB(sb);

	if (!sbi->s_bitmap)
		return;

	affs_brelse(sbi->s_bmap_bh);
	sbi->s_bmap_bh = NULL;
	sbi->s_last_bmap = ~0;
	kfree(sbi->s_bitmap);
	sbi->s_bitmap = NULL;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/affs/bitmap.c
	3	*
	4	* (c) 1996 Hans-Joachim Widmaier
	5	*
	6	* bitmap.c contains the code that handles all bitmap related stuff -
	7	* block allocation, deallocation, calculation of free space.
	8	*/
	9
	10	#include "affs.h"
	11
	12	/* This is, of course, shamelessly stolen from fs/minix */
	13
febfcf91	14	static const int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };
1da177e4 LT	15
	16	static u32
	17	affs_count_free_bits(u32 blocksize, const void *data)
	18	{
	19	const u32 *map;
	20	u32 free;
	21	u32 tmp;
	22
	23	map = data;
	24	free = 0;
	25	for (blocksize /= 4; blocksize > 0; blocksize--) {
	26	tmp = *map++;
	27	while (tmp) {
	28	free += nibblemap[tmp & 0xf];
	29	tmp >>= 4;
	30	}
	31	}
	32
	33	return free;
	34	}
	35
	36	u32
	37	affs_count_free_blocks(struct super_block *sb)
	38	{
	39	struct affs_bm_info *bm;
	40	u32 free;
	41	int i;
	42
	43	pr_debug("AFFS: count_free_blocks()\n");
	44
	45	if (sb->s_flags & MS_RDONLY)
	46	return 0;
	47
7d135a5d	48	mutex_lock(&AFFS_SB(sb)->s_bmlock);
1da177e4 LT	49
	50	bm = AFFS_SB(sb)->s_bitmap;
	51	free = 0;
	52	for (i = AFFS_SB(sb)->s_bmap_count; i > 0; bm++, i--)
	53	free += bm->bm_free;
	54
7d135a5d	55	mutex_unlock(&AFFS_SB(sb)->s_bmlock);
1da177e4 LT	56
	57	return free;
	58	}
	59
	60	void
	61	affs_free_block(struct super_block *sb, u32 block)
	62	{
	63	struct affs_sb_info *sbi = AFFS_SB(sb);
	64	struct affs_bm_info *bm;
	65	struct buffer_head *bh;
	66	u32 blk, bmap, bit, mask, tmp;
	67	__be32 *data;
	68
	69	pr_debug("AFFS: free_block(%u)\n", block);
	70
	71	if (block > sbi->s_partition_size)
	72	goto err_range;
	73
	74	blk = block - sbi->s_reserved;
	75	bmap = blk / sbi->s_bmap_bits;
	76	bit = blk % sbi->s_bmap_bits;
	77	bm = &sbi->s_bitmap[bmap];
	78
7d135a5d	79	mutex_lock(&sbi->s_bmlock);
1da177e4 LT	80
	81	bh = sbi->s_bmap_bh;
	82	if (sbi->s_last_bmap != bmap) {
	83	affs_brelse(bh);
	84	bh = affs_bread(sb, bm->bm_key);
	85	if (!bh)
	86	goto err_bh_read;
	87	sbi->s_bmap_bh = bh;
	88	sbi->s_last_bmap = bmap;
	89	}
	90
	91	mask = 1 << (bit & 31);
	92	data = (__be32 *)bh->b_data + bit / 32 + 1;
	93
	94	/* mark block free */
	95	tmp = be32_to_cpu(*data);
	96	if (tmp & mask)
	97	goto err_free;
	98	*data = cpu_to_be32(tmp \| mask);
	99
	100	/* fix checksum */
	101	tmp = be32_to_cpu((__be32 )bh->b_data);
	102	(__be32 )bh->b_data = cpu_to_be32(tmp - mask);
	103
	104	mark_buffer_dirty(bh);
	105	sb->s_dirt = 1;
	106	bm->bm_free++;
	107
7d135a5d	108	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	109	return;
	110
	111	err_free:
	112	affs_warning(sb,"affs_free_block","Trying to free block %u which is already free", block);
7d135a5d	113	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	114	return;
	115
	116	err_bh_read:
	117	affs_error(sb,"affs_free_block","Cannot read bitmap block %u", bm->bm_key);
	118	sbi->s_bmap_bh = NULL;
	119	sbi->s_last_bmap = ~0;
7d135a5d	120	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	121	return;
	122
	123	err_range:
	124	affs_error(sb, "affs_free_block","Block %u outside partition", block);
	125	return;
	126	}
	127
	128	/*
	129	* Allocate a block in the given allocation zone.
	130	* Since we have to byte-swap the bitmap on little-endian
3ad2f3fb	131	* machines, this is rather expensive. Therefore we will
1da177e4 LT	132	* preallocate up to 16 blocks from the same word, if
	133	* possible. We are not doing preallocations in the
	134	* header zone, though.
	135	*/
	136
	137	u32
	138	affs_alloc_block(struct inode *inode, u32 goal)
	139	{
	140	struct super_block *sb;
	141	struct affs_sb_info *sbi;
	142	struct affs_bm_info *bm;
	143	struct buffer_head *bh;
	144	__be32 data, enddata;
	145	u32 blk, bmap, bit, mask, mask2, tmp;
	146	int i;
	147
	148	sb = inode->i_sb;
	149	sbi = AFFS_SB(sb);
	150
	151	pr_debug("AFFS: balloc(inode=%lu,goal=%u): ", inode->i_ino, goal);
	152
	153	if (AFFS_I(inode)->i_pa_cnt) {
	154	pr_debug("%d\n", AFFS_I(inode)->i_lastalloc+1);
	155	AFFS_I(inode)->i_pa_cnt--;
	156	return ++AFFS_I(inode)->i_lastalloc;
	157	}
	158
	159	if (!goal \|\| goal > sbi->s_partition_size) {
	160	if (goal)
	161	affs_warning(sb, "affs_balloc", "invalid goal %d", goal);
	162	//if (!AFFS_I(inode)->i_last_block)
	163	// affs_warning(sb, "affs_balloc", "no last alloc block");
	164	goal = sbi->s_reserved;
	165	}
	166
	167	blk = goal - sbi->s_reserved;
	168	bmap = blk / sbi->s_bmap_bits;
	169	bm = &sbi->s_bitmap[bmap];
	170
7d135a5d	171	mutex_lock(&sbi->s_bmlock);
1da177e4 LT	172
	173	if (bm->bm_free)
	174	goto find_bmap_bit;
	175
	176	find_bmap:
	177	/* search for the next bmap buffer with free bits */
	178	i = sbi->s_bmap_count;
	179	do {
	180	if (--i < 0)
	181	goto err_full;
	182	bmap++;
	183	bm++;
	184	if (bmap < sbi->s_bmap_count)
	185	continue;
	186	/* restart search at zero */
	187	bmap = 0;
	188	bm = sbi->s_bitmap;
	189	} while (!bm->bm_free);
	190	blk = bmap * sbi->s_bmap_bits;
	191
	192	find_bmap_bit:
	193
	194	bh = sbi->s_bmap_bh;
	195	if (sbi->s_last_bmap != bmap) {
	196	affs_brelse(bh);
	197	bh = affs_bread(sb, bm->bm_key);
	198	if (!bh)
	199	goto err_bh_read;
	200	sbi->s_bmap_bh = bh;
	201	sbi->s_last_bmap = bmap;
	202	}
	203
	204	/* find an unused block in this bitmap block */
	205	bit = blk % sbi->s_bmap_bits;
	206	data = (__be32 *)bh->b_data + bit / 32 + 1;
	207	enddata = (__be32 )((u8 )bh->b_data + sb->s_blocksize);
	208	mask = ~0UL << (bit & 31);
	209	blk &= ~31UL;
	210
	211	tmp = be32_to_cpu(*data);
	212	if (tmp & mask)
	213	goto find_bit;
	214
	215	/* scan the rest of the buffer */
	216	do {
	217	blk += 32;
	218	if (++data >= enddata)
	219	/* didn't find something, can only happen
	220	* if scan didn't start at 0, try next bmap
	221	*/
	222	goto find_bmap;
	223	} while (!*data);
	224	tmp = be32_to_cpu(*data);
	225	mask = ~0;
	226
	227	find_bit:
	228	/* finally look for a free bit in the word */
	229	bit = ffs(tmp & mask) - 1;
	230	blk += bit + sbi->s_reserved;
	231	mask2 = mask = 1 << (bit & 31);
	232	AFFS_I(inode)->i_lastalloc = blk;
	233
	234	/* prealloc as much as possible within this word */
	235	while ((mask2 <<= 1)) {
236	if (!(tmp & mask2))
237	break;
238	AFFS_I(inode)->i_pa_cnt++;
239	mask \|= mask2;
240	}
241	bm->bm_free -= AFFS_I(inode)->i_pa_cnt + 1;
242
243	*data = cpu_to_be32(tmp & ~mask);
244
245	/* fix checksum */
246	tmp = be32_to_cpu((__be32 )bh->b_data);
247	(__be32 )bh->b_data = cpu_to_be32(tmp + mask);
248
249	mark_buffer_dirty(bh);
250	sb->s_dirt = 1;
251
7d135a5d	252	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	253
	254	pr_debug("%d\n", blk);
	255	return blk;
	256
	257	err_bh_read:
	258	affs_error(sb,"affs_read_block","Cannot read bitmap block %u", bm->bm_key);
	259	sbi->s_bmap_bh = NULL;
	260	sbi->s_last_bmap = ~0;
	261	err_full:
7d135a5d	262	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	263	pr_debug("failed\n");
	264	return 0;
	265	}
	266
	267	int affs_init_bitmap(struct super_block sb, int flags)
	268	{
	269	struct affs_bm_info *bm;
	270	struct buffer_head bmap_bh = NULL, bh = NULL;
	271	__be32 *bmap_blk;
	272	u32 size, blk, end, offset, mask;
	273	int i, res = 0;
	274	struct affs_sb_info *sbi = AFFS_SB(sb);
	275
	276	if (*flags & MS_RDONLY)
	277	return 0;
	278
	279	if (!AFFS_ROOT_TAIL(sb, sbi->s_root_bh)->bm_flag) {
	280	printk(KERN_NOTICE "AFFS: Bitmap invalid - mounting %s read only\n",
	281	sb->s_id);
	282	*flags \|= MS_RDONLY;
	283	return 0;
	284	}
	285
	286	sbi->s_last_bmap = ~0;
	287	sbi->s_bmap_bh = NULL;
	288	sbi->s_bmap_bits = sb->s_blocksize * 8 - 32;
	289	sbi->s_bmap_count = (sbi->s_partition_size - sbi->s_reserved +
	290	sbi->s_bmap_bits - 1) / sbi->s_bmap_bits;
	291	size = sbi->s_bmap_count * sizeof(*bm);
b593e48d	292	bm = sbi->s_bitmap = kzalloc(size, GFP_KERNEL);
1da177e4 LT	293	if (!sbi->s_bitmap) {
	294	printk(KERN_ERR "AFFS: Bitmap allocation failed\n");
	295	return -ENOMEM;
	296	}
1da177e4 LT	297
	298	bmap_blk = (__be32 *)sbi->s_root_bh->b_data;
	299	blk = sb->s_blocksize / 4 - 49;
	300	end = blk + 25;
	301
	302	for (i = sbi->s_bmap_count; i > 0; bm++, i--) {
	303	affs_brelse(bh);
	304
	305	bm->bm_key = be32_to_cpu(bmap_blk[blk]);
	306	bh = affs_bread(sb, bm->bm_key);
	307	if (!bh) {
	308	printk(KERN_ERR "AFFS: Cannot read bitmap\n");
	309	res = -EIO;
	310	goto out;
	311	}
	312	if (affs_checksum_block(sb, bh)) {
	313	printk(KERN_WARNING "AFFS: Bitmap %u invalid - mounting %s read only.\n",
	314	bm->bm_key, sb->s_id);
	315	*flags \|= MS_RDONLY;
	316	goto out;
	317	}
	318	pr_debug("AFFS: read bitmap block %d: %d\n", blk, bm->bm_key);
	319	bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);
	320
	321	/* Don't try read the extension if this is the last block,
	322	* but we also need the right bm pointer below
	323	*/
	324	if (++blk < end \|\| i == 1)
	325	continue;
	326	if (bmap_bh)
	327	affs_brelse(bmap_bh);
	328	bmap_bh = affs_bread(sb, be32_to_cpu(bmap_blk[blk]));
	329	if (!bmap_bh) {
	330	printk(KERN_ERR "AFFS: Cannot read bitmap extension\n");
	331	res = -EIO;
	332	goto out;
	333	}
	334	bmap_blk = (__be32 *)bmap_bh->b_data;
	335	blk = 0;
	336	end = sb->s_blocksize / 4 - 1;
	337	}
	338
	339	offset = (sbi->s_partition_size - sbi->s_reserved) % sbi->s_bmap_bits;
	340	mask = ~(0xFFFFFFFFU << (offset & 31));
	341	pr_debug("last word: %d %d %d\n", offset, offset / 32 + 1, mask);
	342	offset = offset / 32 + 1;
	343
	344	if (mask) {
	345	u32 old, new;
	346
	347	/* Mark unused bits in the last word as allocated */
	348	old = be32_to_cpu(((__be32 *)bh->b_data)[offset]);
	349	new = old & mask;
	350	//if (old != new) {
	351	((__be32 *)bh->b_data)[offset] = cpu_to_be32(new);
	352	/* fix checksum */
	353	//new -= old;
	354	//old = be32_to_cpu((__be32 )bh->b_data);
	355	//(__be32 )bh->b_data = cpu_to_be32(old - new);
	356	//mark_buffer_dirty(bh);
	357	//}
	358	/* correct offset for the bitmap count below */
	359	//offset++;
	360	}
361	while (++offset < sb->s_blocksize / 4)
362	((__be32 *)bh->b_data)[offset] = 0;
363	((__be32 *)bh->b_data)[0] = 0;
364	((__be32 *)bh->b_data)[0] = cpu_to_be32(-affs_checksum_block(sb, bh));
365	mark_buffer_dirty(bh);
366
367	/* recalculate bitmap count for last block */
368	bm--;
369	bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);
370
371	out:
372	affs_brelse(bh);
373	affs_brelse(bmap_bh);
374	return res;
375	}
376
377	void affs_free_bitmap(struct super_block *sb)
378	{
379	struct affs_sb_info *sbi = AFFS_SB(sb);
380
381	if (!sbi->s_bitmap)
382	return;
383
384	affs_brelse(sbi->s_bmap_bh);
385	sbi->s_bmap_bh = NULL;
386	sbi->s_last_bmap = ~0;
387	kfree(sbi->s_bitmap);
388	sbi->s_bitmap = NULL;
389	}