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Commit 4d20851d authored by Jeff Mahoney's avatar Jeff Mahoney Committed by Linus Torvalds
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reiserfs: remove first_zero_hint 



The first_zero_hint metadata caching was never actually used, and it's of
dubious optimization quality.  This patch removes it.

It doesn't actually shrink the size of the reiserfs_bitmap_info struct, since
that doesn't work with block sizes larger than 8K.  There was a big fixme in
there, and with all the work lately in allowing block size > page size, I
might as well kill the fixme as well.

Signed-off-by: default avatarJeff Mahoney <jeffm@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3ee16670

fs/reiserfs/bitmap.c

+12 −17
Original line number Original line Diff line number Diff line
@@ -273,7 +273,7 @@ static inline int block_group_used(struct super_block *s, u32 id) 
	 * to make a better decision. This favors long-term performace gain

	 * to make a better decision. This favors long-term performace gain

	 * with a better on-disk layout vs. a short term gain of skipping the

	 * with a better on-disk layout vs. a short term gain of skipping the

	 * read and potentially having a bad placement. */

	 * read and potentially having a bad placement. */

	if (info->first_zero_hint == 0) {

	if (info->free_count == UINT_MAX) {

		struct buffer_head *bh = reiserfs_read_bitmap_block(s, bm);

		struct buffer_head *bh = reiserfs_read_bitmap_block(s, bm);

		brelse(bh);

		brelse(bh);

	}

	}
@@ -1214,28 +1214,23 @@ void reiserfs_cache_bitmap_metadata(struct super_block *sb, 
{

{

	unsigned long *cur = (unsigned long *)(bh->b_data + bh->b_size);

	unsigned long *cur = (unsigned long *)(bh->b_data + bh->b_size);





	info->first_zero_hint = 1 << (sb->s_blocksize_bits + 3);

	/* The first bit must ALWAYS be 1 */

	BUG_ON(!reiserfs_test_le_bit(0, (unsigned long *)bh->b_data));



	info->free_count = 0;





	while (--cur >= (unsigned long *)bh->b_data) {

	while (--cur >= (unsigned long *)bh->b_data) {

		int base = ((char *)cur - bh->b_data) << 3;

		int i;





		/* 0 and ~0 are special, we can optimize for them */

		/* 0 and ~0 are special, we can optimize for them */

		if (*cur == 0) {

		if (*cur == 0)

			info->first_zero_hint = base;

			info->free_count += BITS_PER_LONG;

			info->free_count += BITS_PER_LONG;

		} else if (*cur != ~0L) {       /* A mix, investigate */

		else if (*cur != ~0L)	/* A mix, investigate */

			int b;

			for (i = BITS_PER_LONG - 1; i >= 0; i--)

			for (b = BITS_PER_LONG - 1; b >= 0; b--) {

				if (!reiserfs_test_le_bit(i, cur))

				if (!reiserfs_test_le_bit(b, cur)) {

					info->first_zero_hint = base + b;

					info->free_count++;

					info->free_count++;

	}

	}

}

}

		}

	}

	/* The first bit must ALWAYS be 1 */

	BUG_ON(info->first_zero_hint == 0);

}





struct buffer_head *reiserfs_read_bitmap_block(struct super_block *sb,

struct buffer_head *reiserfs_read_bitmap_block(struct super_block *sb,

                                               unsigned int bitmap)

                                               unsigned int bitmap)
@@ -1264,7 +1259,7 @@ struct buffer_head *reiserfs_read_bitmap_block(struct super_block *sb, 
		BUG_ON(!buffer_uptodate(bh));

		BUG_ON(!buffer_uptodate(bh));

		BUG_ON(atomic_read(&bh->b_count) == 0);

		BUG_ON(atomic_read(&bh->b_count) == 0);





		if (info->first_zero_hint == 0)

		if (info->free_count == UINT_MAX)

			reiserfs_cache_bitmap_metadata(sb, bh, info);

			reiserfs_cache_bitmap_metadata(sb, bh, info);

	}

	}
@@ -1279,7 +1274,7 @@ int reiserfs_init_bitmap_cache(struct super_block *sb) 
	if (bitmap == NULL)

	if (bitmap == NULL)

		return -ENOMEM;

		return -ENOMEM;





	memset(bitmap, 0, sizeof (*bitmap) * SB_BMAP_NR(sb));

	memset(bitmap, 0xff, sizeof(*bitmap) * SB_BMAP_NR(sb));





	SB_AP_BITMAP(sb) = bitmap;

	SB_AP_BITMAP(sb) = bitmap;

fs/reiserfs/resize.c

+0 −6
Original line number Original line Diff line number Diff line
@@ -143,7 +143,6 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new) 
			mark_buffer_dirty(bh);

			mark_buffer_dirty(bh);

			sync_dirty_buffer(bh);

			sync_dirty_buffer(bh);

			// update bitmap_info stuff

			// update bitmap_info stuff

			bitmap[i].first_zero_hint = 1;

			bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;

			bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;

			brelse(bh);

			brelse(bh);

		}

		}
@@ -173,8 +172,6 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new) 
	for (i = block_r; i < s->s_blocksize * 8; i++)

	for (i = block_r; i < s->s_blocksize * 8; i++)

		reiserfs_test_and_clear_le_bit(i, bh->b_data);

		reiserfs_test_and_clear_le_bit(i, bh->b_data);

	info->free_count += s->s_blocksize * 8 - block_r;

	info->free_count += s->s_blocksize * 8 - block_r;

	if (!info->first_zero_hint)

		info->first_zero_hint = block_r;





	journal_mark_dirty(&th, s, bh);

	journal_mark_dirty(&th, s, bh);

	brelse(bh);

	brelse(bh);
@@ -196,9 +193,6 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new) 
	brelse(bh);

	brelse(bh);





	info->free_count -= s->s_blocksize * 8 - block_r_new;

	info->free_count -= s->s_blocksize * 8 - block_r_new;

	/* Extreme case where last bitmap is the only valid block in itself. */

	if (!info->free_count)

		info->first_zero_hint = 0;

	/* update super */

	/* update super */

	reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);

	reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);

	free_blocks = SB_FREE_BLOCKS(s);

	free_blocks = SB_FREE_BLOCKS(s);

include/linux/reiserfs_fs_sb.h

+1 −3
Original line number Original line Diff line number Diff line
@@ -265,9 +265,7 @@ enum journal_state_bits { 
typedef __u32(*hashf_t) (const signed char *, int);

typedef __u32(*hashf_t) (const signed char *, int);





struct reiserfs_bitmap_info {

struct reiserfs_bitmap_info {

	// FIXME: Won't work with block sizes > 8K

	__u32 free_count;

	__u16 first_zero_hint;

	__u16 free_count;

};

};





struct proc_dir_entry;

struct proc_dir_entry;