mke2fs: optimize fix_cluster_bg_counts()

Instead of iterating over the allocation bitmap using
ext2fs_test_block_bitmap2(), bit by bit, use
ext2fs_find_first_set_block_bitmap2() instead.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index c45b42f..acc603d 100644 (file)
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -2332,30 +2332,43 @@ static int mke2fs_discard_device(ext2_filsys fs)
 
 static void fix_cluster_bg_counts(ext2_filsys fs)
 {
-       blk64_t cluster, num_clusters, tot_free;
-       unsigned num = 0;
-       int     grp_free, num_free, group;
-
-       num_clusters = EXT2FS_B2C(fs, ext2fs_blocks_count(fs->super));
-       tot_free = num_free = group = grp_free = 0;
-       for (cluster = EXT2FS_B2C(fs, fs->super->s_first_data_block);
-            cluster < num_clusters; cluster++) {
-               if (!ext2fs_test_block_bitmap2(fs->block_map,
-                                              EXT2FS_C2B(fs, cluster))) {
-                       grp_free++;
-                       tot_free++;
+       blk64_t         block, num_blocks, last_block, next;
+       blk64_t         tot_free = 0;
+       errcode_t       retval;
+       dgrp_t          group = 0;
+       int             grp_free = 0;
+
+       num_blocks = ext2fs_blocks_count(fs->super);
+       last_block = ext2fs_group_last_block2(fs, group);
+       block = fs->super->s_first_data_block;
+       while (block < num_blocks) {
+               retval = ext2fs_find_first_zero_block_bitmap2(fs->block_map,
+                                               block, last_block, &next);
+               if (retval == 0)
+                       block = next;
+               else {
+                       block = last_block + 1;
+                       goto next_bg;
                }
-               num++;
-               if ((num == fs->super->s_clusters_per_group) ||
-                   (cluster == num_clusters-1)) {
+
+               retval = ext2fs_find_first_set_block_bitmap2(fs->block_map,
+                                               block, last_block, &next);
+               if (retval)
+                       next = last_block + 1;
+               grp_free += EXT2FS_NUM_B2C(fs, next - block);
+               tot_free += next - block;
+               block = next;
+
+               if (block > last_block) {
+               next_bg:
                        ext2fs_bg_free_blocks_count_set(fs, group, grp_free);
                        ext2fs_group_desc_csum_set(fs, group);
-                       num = 0;
                        grp_free = 0;
                        group++;
+                       last_block = ext2fs_group_last_block2(fs, group);
                }
        }
-       ext2fs_free_blocks_count_set(fs->super, EXT2FS_C2B(fs, tot_free));
+       ext2fs_free_blocks_count_set(fs->super, tot_free);
 }
 
 static int create_quota_inodes(ext2_filsys fs)