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.
Update: Was missing the 0 -> 0xff memset change.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
---
fs/reiserfs/bitmap.c | 29 ++++++++++++-----------------
fs/reiserfs/resize.c | 6 ------
include/linux/reiserfs_fs_sb.h | 4 +---
3 files changed, 13 insertions(+), 26 deletions(-)
Index: b/fs/reiserfs/bitmap.c
===================================================================
--- a/fs/reiserfs/bitmap.c 2007-10-18 14:08:49.000000000 -0400
+++ b/fs/reiserfs/bitmap.c 2007-10-18 14:10:47.000000000 -0400
@@ -273,7 +273,7 @@ static inline int block_group_used(struc
* 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);
}
@@ -1271,27 +1271,22 @@ void reiserfs_cache_bitmap_metadata(stru
{
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,
@@ -1321,7 +1316,7 @@ struct buffer_head *reiserfs_read_bitmap
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);
}
@@ -1336,7 +1331,7 @@ int reiserfs_init_bitmap_cache(struct su
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;
Index: b/fs/reiserfs/resize.c
===================================================================
--- a/fs/reiserfs/resize.c 2007-10-18 14:08:49.000000000 -0400
+++ b/fs/reiserfs/resize.c 2007-10-18 14:10:47.000000000 -0400
@@ -143,7 +143,6 @@ int reiserfs_resize(struct super_block *
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 *
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 *
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);
Index: b/include/linux/reiserfs_fs_sb.h
===================================================================
--- a/include/linux/reiserfs_fs_sb.h 2007-10-18 14:08:45.000000000 -0400
+++ b/include/linux/reiserfs_fs_sb.h 2007-10-18 14:09:35.000000000 -0400
@@ -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;
--
Jeff Mahoney
SUSE Labs
-
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