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reiserfs: remove first_zero_hint

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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: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jeff Mahoney 2007-10-18 23:39:26 -07:00 committed by Linus Torvalds
parent 3ee1667042
commit 4d20851d37
3 changed files with 13 additions and 26 deletions
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29
fs/reiserfs/bitmap.c
View file

@ -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
* with a better on-disk layout vs. a short term gain of skipping the
* 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);
brelse(bh);
}
@ -1214,27 +1214,22 @@ void reiserfs_cache_bitmap_metadata(struct super_block *sb,
{
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) {
int base = ((char *)cur - bh->b_data) << 3;
int i;
/* 0 and ~0 are special, we can optimize for them */
if (*cur == 0) {
info->first_zero_hint = base;
if (*cur == 0)
info->free_count += BITS_PER_LONG;
} else if (*cur != ~0L) { /* A mix, investigate */
int b;
for (b = BITS_PER_LONG - 1; b >= 0; b--) {
if (!reiserfs_test_le_bit(b, cur)) {
info->first_zero_hint = base + b;
else if (*cur != ~0L) /* A mix, investigate */
for (i = BITS_PER_LONG - 1; i >= 0; i--)
if (!reiserfs_test_le_bit(i, cur))
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,
@ -1264,7 +1259,7 @@ struct buffer_head *reiserfs_read_bitmap_block(struct super_block *sb,
BUG_ON(!buffer_uptodate(bh));
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);
}
@ -1279,7 +1274,7 @@ int reiserfs_init_bitmap_cache(struct super_block *sb)
if (bitmap == NULL)
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;

6
fs/reiserfs/resize.c
View file

@ -143,7 +143,6 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
mark_buffer_dirty(bh);
sync_dirty_buffer(bh);
// update bitmap_info stuff
bitmap[i].first_zero_hint = 1;
bitmap[i].free_count = sb_blocksize(sb) * 8 - 1;
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++)
reiserfs_test_and_clear_le_bit(i, bh->b_data);
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);
brelse(bh);
@ -196,9 +193,6 @@ int reiserfs_resize(struct super_block *s, unsigned long block_count_new)
brelse(bh);
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 */
reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1);
free_blocks = SB_FREE_BLOCKS(s);

4
include/linux/reiserfs_fs_sb.h
View file

@ -265,9 +265,7 @@ enum journal_state_bits {
typedef __u32(*hashf_t) (const signed char *, int);
struct reiserfs_bitmap_info {
// FIXME: Won't work with block sizes > 8K
__u16 first_zero_hint;
__u16 free_count;
__u32 free_count;
};
struct proc_dir_entry;