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: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/reiserfs/bitmap.c b/fs/reiserfs/bitmap.c
index f727517..f09a6f6 100644 (file)
--- a/fs/reiserfs/bitmap.c
+++ b/fs/reiserfs/bitmap.c
@@ -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;
 

diff --git a/fs/reiserfs/resize.c b/fs/reiserfs/resize.c
index 3bec2f9..66f1cda 100644 (file)
--- a/fs/reiserfs/resize.c
+++ b/fs/reiserfs/resize.c
@@ -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);

diff --git a/include/linux/reiserfs_fs_sb.h b/include/linux/reiserfs_fs_sb.h
index ff9e923..10fa0c8 100644 (file)
--- a/include/linux/reiserfs_fs_sb.h
+++ b/include/linux/reiserfs_fs_sb.h
@@ -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;