[linux.git] / fs / affs / bitmap.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  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 <linux/slab.h>
#include "affs.h"

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

	pr_debug("%s()\n", __func__);

	if (sb_rdonly(sb))
		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("%s(%u)\n", __func__, 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);
	affs_mark_sb_dirty(sb);
	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);
}

/*
 * 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("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);
	affs_mark_sb_dirty(sb);

	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 & SB_RDONLY)
		return 0;

	if (!AFFS_ROOT_TAIL(sb, sbi->s_root_bh)->bm_flag) {
		pr_notice("Bitmap invalid - mounting %s read only\n", sb->s_id);
		*flags |= SB_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) {
		pr_err("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) {
			pr_err("Cannot read bitmap\n");
			res = -EIO;
			goto out;
		}
		if (affs_checksum_block(sb, bh)) {
			pr_warn("Bitmap %u invalid - mounting %s read only.\n",
				bm->bm_key, sb->s_id);
			*flags |= SB_RDONLY;
			goto out;
		}
		pr_debug("read bitmap block %d: %d\n", blk, bm->bm_key);
		bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 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) {
			pr_err("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 = memweight(bh->b_data + 4, sb->s_blocksize - 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
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/affs/bitmap.c
	4	*
	5	* (c) 1996 Hans-Joachim Widmaier
	6	*
	7	* bitmap.c contains the code that handles all bitmap related stuff -
	8	* block allocation, deallocation, calculation of free space.
	9	*/
	10
5a0e3ad6	11	#include <linux/slab.h>
1da177e4 LT	12	#include "affs.h"
1da177e4 LT	13
1da177e4 LT	14	u32
	15	affs_count_free_blocks(struct super_block *sb)
	16	{
	17	struct affs_bm_info *bm;
	18	u32 free;
	19	int i;
	20
9606d9aa	21	pr_debug("%s()\n", __func__);
1da177e4	22
bc98a42c	23	if (sb_rdonly(sb))
1da177e4 LT	24	return 0;
1da177e4 LT	25
7d135a5d	26	mutex_lock(&AFFS_SB(sb)->s_bmlock);
1da177e4 LT	27
	28	bm = AFFS_SB(sb)->s_bitmap;
	29	free = 0;
	30	for (i = AFFS_SB(sb)->s_bmap_count; i > 0; bm++, i--)
	31	free += bm->bm_free;
	32
7d135a5d	33	mutex_unlock(&AFFS_SB(sb)->s_bmlock);
1da177e4 LT	34
	35	return free;
	36	}
	37
	38	void
	39	affs_free_block(struct super_block *sb, u32 block)
	40	{
	41	struct affs_sb_info *sbi = AFFS_SB(sb);
	42	struct affs_bm_info *bm;
	43	struct buffer_head *bh;
	44	u32 blk, bmap, bit, mask, tmp;
	45	__be32 *data;
	46
9606d9aa	47	pr_debug("%s(%u)\n", __func__, block);
1da177e4 LT	48
	49	if (block > sbi->s_partition_size)
	50	goto err_range;
	51
	52	blk = block - sbi->s_reserved;
	53	bmap = blk / sbi->s_bmap_bits;
	54	bit = blk % sbi->s_bmap_bits;
	55	bm = &sbi->s_bitmap[bmap];
	56
7d135a5d	57	mutex_lock(&sbi->s_bmlock);
1da177e4 LT	58
	59	bh = sbi->s_bmap_bh;
	60	if (sbi->s_last_bmap != bmap) {
	61	affs_brelse(bh);
	62	bh = affs_bread(sb, bm->bm_key);
	63	if (!bh)
	64	goto err_bh_read;
	65	sbi->s_bmap_bh = bh;
	66	sbi->s_last_bmap = bmap;
	67	}
	68
	69	mask = 1 << (bit & 31);
	70	data = (__be32 *)bh->b_data + bit / 32 + 1;
	71
	72	/* mark block free */
	73	tmp = be32_to_cpu(*data);
	74	if (tmp & mask)
	75	goto err_free;
	76	*data = cpu_to_be32(tmp \| mask);
	77
	78	/* fix checksum */
	79	tmp = be32_to_cpu((__be32 )bh->b_data);
	80	(__be32 )bh->b_data = cpu_to_be32(tmp - mask);
	81
	82	mark_buffer_dirty(bh);
3dd84782	83	affs_mark_sb_dirty(sb);
1da177e4 LT	84	bm->bm_free++;
1da177e4 LT	85
7d135a5d	86	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	87	return;
	88
	89	err_free:
	90	affs_warning(sb,"affs_free_block","Trying to free block %u which is already free", block);
7d135a5d	91	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	92	return;
	93
	94	err_bh_read:
	95	affs_error(sb,"affs_free_block","Cannot read bitmap block %u", bm->bm_key);
	96	sbi->s_bmap_bh = NULL;
	97	sbi->s_last_bmap = ~0;
7d135a5d	98	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	99	return;
	100
	101	err_range:
	102	affs_error(sb, "affs_free_block","Block %u outside partition", block);
1da177e4 LT	103	}
	104
	105	/*
	106	* Allocate a block in the given allocation zone.
	107	* Since we have to byte-swap the bitmap on little-endian
3ad2f3fb	108	* machines, this is rather expensive. Therefore we will
1da177e4 LT	109	* preallocate up to 16 blocks from the same word, if
	110	* possible. We are not doing preallocations in the
	111	* header zone, though.
	112	*/
	113
	114	u32
	115	affs_alloc_block(struct inode *inode, u32 goal)
	116	{
	117	struct super_block *sb;
	118	struct affs_sb_info *sbi;
	119	struct affs_bm_info *bm;
	120	struct buffer_head *bh;
	121	__be32 data, enddata;
	122	u32 blk, bmap, bit, mask, mask2, tmp;
	123	int i;
	124
	125	sb = inode->i_sb;
	126	sbi = AFFS_SB(sb);
	127
9606d9aa	128	pr_debug("balloc(inode=%lu,goal=%u): ", inode->i_ino, goal);
1da177e4 LT	129
	130	if (AFFS_I(inode)->i_pa_cnt) {
	131	pr_debug("%d\n", AFFS_I(inode)->i_lastalloc+1);
	132	AFFS_I(inode)->i_pa_cnt--;
	133	return ++AFFS_I(inode)->i_lastalloc;
	134	}
	135
	136	if (!goal \|\| goal > sbi->s_partition_size) {
	137	if (goal)
	138	affs_warning(sb, "affs_balloc", "invalid goal %d", goal);
	139	//if (!AFFS_I(inode)->i_last_block)
	140	// affs_warning(sb, "affs_balloc", "no last alloc block");
	141	goal = sbi->s_reserved;
	142	}
	143
	144	blk = goal - sbi->s_reserved;
	145	bmap = blk / sbi->s_bmap_bits;
	146	bm = &sbi->s_bitmap[bmap];
	147
7d135a5d	148	mutex_lock(&sbi->s_bmlock);
1da177e4 LT	149
	150	if (bm->bm_free)
	151	goto find_bmap_bit;
	152
	153	find_bmap:
	154	/* search for the next bmap buffer with free bits */
	155	i = sbi->s_bmap_count;
	156	do {
	157	if (--i < 0)
	158	goto err_full;
	159	bmap++;
	160	bm++;
	161	if (bmap < sbi->s_bmap_count)
	162	continue;
	163	/* restart search at zero */
	164	bmap = 0;
	165	bm = sbi->s_bitmap;
	166	} while (!bm->bm_free);
	167	blk = bmap * sbi->s_bmap_bits;
	168
	169	find_bmap_bit:
	170
	171	bh = sbi->s_bmap_bh;
	172	if (sbi->s_last_bmap != bmap) {
	173	affs_brelse(bh);
	174	bh = affs_bread(sb, bm->bm_key);
	175	if (!bh)
	176	goto err_bh_read;
	177	sbi->s_bmap_bh = bh;
	178	sbi->s_last_bmap = bmap;
	179	}
	180
	181	/* find an unused block in this bitmap block */
	182	bit = blk % sbi->s_bmap_bits;
	183	data = (__be32 *)bh->b_data + bit / 32 + 1;
	184	enddata = (__be32 )((u8 )bh->b_data + sb->s_blocksize);
	185	mask = ~0UL << (bit & 31);
	186	blk &= ~31UL;
	187
	188	tmp = be32_to_cpu(*data);
	189	if (tmp & mask)
	190	goto find_bit;
	191
	192	/* scan the rest of the buffer */
	193	do {
	194	blk += 32;
	195	if (++data >= enddata)
	196	/* didn't find something, can only happen
	197	* if scan didn't start at 0, try next bmap
	198	*/
	199	goto find_bmap;
	200	} while (!*data);
	201	tmp = be32_to_cpu(*data);
	202	mask = ~0;
	203
	204	find_bit:
	205	/* finally look for a free bit in the word */
	206	bit = ffs(tmp & mask) - 1;
	207	blk += bit + sbi->s_reserved;
	208	mask2 = mask = 1 << (bit & 31);
	209	AFFS_I(inode)->i_lastalloc = blk;
	210
	211	/* prealloc as much as possible within this word */
	212	while ((mask2 <<= 1)) {
213	if (!(tmp & mask2))
214	break;
215	AFFS_I(inode)->i_pa_cnt++;
216	mask \|= mask2;
217	}
218	bm->bm_free -= AFFS_I(inode)->i_pa_cnt + 1;
219
220	*data = cpu_to_be32(tmp & ~mask);
221
222	/* fix checksum */
223	tmp = be32_to_cpu((__be32 )bh->b_data);
224	(__be32 )bh->b_data = cpu_to_be32(tmp + mask);
225
226	mark_buffer_dirty(bh);
3dd84782	227	affs_mark_sb_dirty(sb);
1da177e4	228
7d135a5d	229	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	230
	231	pr_debug("%d\n", blk);
	232	return blk;
	233
	234	err_bh_read:
	235	affs_error(sb,"affs_read_block","Cannot read bitmap block %u", bm->bm_key);
	236	sbi->s_bmap_bh = NULL;
	237	sbi->s_last_bmap = ~0;
	238	err_full:
7d135a5d	239	mutex_unlock(&sbi->s_bmlock);
1da177e4 LT	240	pr_debug("failed\n");
	241	return 0;
	242	}
	243
	244	int affs_init_bitmap(struct super_block sb, int flags)
	245	{
	246	struct affs_bm_info *bm;
	247	struct buffer_head bmap_bh = NULL, bh = NULL;
	248	__be32 *bmap_blk;
	249	u32 size, blk, end, offset, mask;
	250	int i, res = 0;
	251	struct affs_sb_info *sbi = AFFS_SB(sb);
	252
1751e8a6	253	if (*flags & SB_RDONLY)
1da177e4 LT	254	return 0;
	255
	256	if (!AFFS_ROOT_TAIL(sb, sbi->s_root_bh)->bm_flag) {
0158de12	257	pr_notice("Bitmap invalid - mounting %s read only\n", sb->s_id);
1751e8a6	258	*flags \|= SB_RDONLY;
1da177e4 LT	259	return 0;
	260	}
	261
	262	sbi->s_last_bmap = ~0;
	263	sbi->s_bmap_bh = NULL;
	264	sbi->s_bmap_bits = sb->s_blocksize * 8 - 32;
	265	sbi->s_bmap_count = (sbi->s_partition_size - sbi->s_reserved +
	266	sbi->s_bmap_bits - 1) / sbi->s_bmap_bits;
	267	size = sbi->s_bmap_count * sizeof(*bm);
b593e48d	268	bm = sbi->s_bitmap = kzalloc(size, GFP_KERNEL);
1da177e4	269	if (!sbi->s_bitmap) {
0158de12	270	pr_err("Bitmap allocation failed\n");
1da177e4 LT	271	return -ENOMEM;
1da177e4 LT	272	}
1da177e4 LT	273
	274	bmap_blk = (__be32 *)sbi->s_root_bh->b_data;
	275	blk = sb->s_blocksize / 4 - 49;
	276	end = blk + 25;
	277
	278	for (i = sbi->s_bmap_count; i > 0; bm++, i--) {
	279	affs_brelse(bh);
	280
	281	bm->bm_key = be32_to_cpu(bmap_blk[blk]);
	282	bh = affs_bread(sb, bm->bm_key);
	283	if (!bh) {
0158de12	284	pr_err("Cannot read bitmap\n");
1da177e4 LT	285	res = -EIO;
	286	goto out;
	287	}
	288	if (affs_checksum_block(sb, bh)) {
0158de12 FF	289	pr_warn("Bitmap %u invalid - mounting %s read only.\n",
0158de12 FF	290	bm->bm_key, sb->s_id);
1751e8a6	291	*flags \|= SB_RDONLY;
1da177e4 LT	292	goto out;
1da177e4 LT	293	}
9606d9aa	294	pr_debug("read bitmap block %d: %d\n", blk, bm->bm_key);
0121ad62	295	bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
1da177e4 LT	296
	297	/* Don't try read the extension if this is the last block,
	298	* but we also need the right bm pointer below
	299	*/
	300	if (++blk < end \|\| i == 1)
	301	continue;
	302	if (bmap_bh)
	303	affs_brelse(bmap_bh);
	304	bmap_bh = affs_bread(sb, be32_to_cpu(bmap_blk[blk]));
	305	if (!bmap_bh) {
0158de12	306	pr_err("Cannot read bitmap extension\n");
1da177e4 LT	307	res = -EIO;
	308	goto out;
	309	}
	310	bmap_blk = (__be32 *)bmap_bh->b_data;
	311	blk = 0;
	312	end = sb->s_blocksize / 4 - 1;
	313	}
	314
	315	offset = (sbi->s_partition_size - sbi->s_reserved) % sbi->s_bmap_bits;
	316	mask = ~(0xFFFFFFFFU << (offset & 31));
	317	pr_debug("last word: %d %d %d\n", offset, offset / 32 + 1, mask);
	318	offset = offset / 32 + 1;
	319
	320	if (mask) {
	321	u32 old, new;
	322
	323	/* Mark unused bits in the last word as allocated */
	324	old = be32_to_cpu(((__be32 *)bh->b_data)[offset]);
	325	new = old & mask;
	326	//if (old != new) {
	327	((__be32 *)bh->b_data)[offset] = cpu_to_be32(new);
	328	/* fix checksum */
	329	//new -= old;
	330	//old = be32_to_cpu((__be32 )bh->b_data);
	331	//(__be32 )bh->b_data = cpu_to_be32(old - new);
	332	//mark_buffer_dirty(bh);
	333	//}
	334	/* correct offset for the bitmap count below */
	335	//offset++;
	336	}
	337	while (++offset < sb->s_blocksize / 4)
	338	((__be32 *)bh->b_data)[offset] = 0;
	339	((__be32 *)bh->b_data)[0] = 0;
	340	((__be32 *)bh->b_data)[0] = cpu_to_be32(-affs_checksum_block(sb, bh));
	341	mark_buffer_dirty(bh);
	342
	343	/* recalculate bitmap count for last block */
	344	bm--;
0121ad62	345	bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
1da177e4 LT	346
	347	out:
	348	affs_brelse(bh);
	349	affs_brelse(bmap_bh);
	350	return res;
	351	}
	352
	353	void affs_free_bitmap(struct super_block *sb)
	354	{
	355	struct affs_sb_info *sbi = AFFS_SB(sb);
	356
	357	if (!sbi->s_bitmap)
	358	return;
	359
	360	affs_brelse(sbi->s_bmap_bh);
	361	sbi->s_bmap_bh = NULL;
	362	sbi->s_last_bmap = ~0;
	363	kfree(sbi->s_bitmap);
	364	sbi->s_bitmap = NULL;
	365	}