@@ -1442,6 +1442,8 @@ errcode_t ext2fs_set_generic_bmap_range(ext2fs_generic_bitmap bmap,
void *in);
errcode_t ext2fs_convert_subcluster_bitmap(ext2_filsys fs,
ext2fs_block_bitmap *bitmap);
+errcode_t ext2fs_count_used_clusters(ext2_filsys fs, blk64_t start,
+ blk64_t end, blk64_t *out);
/* get_num_dirs.c */
extern errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ext2_ino_t *ret_num_dirs);
@@ -940,3 +940,38 @@ errcode_t ext2fs_find_first_set_generic_bmap(ext2fs_generic_bitmap bitmap,
return ENOENT;
}
+
+errcode_t ext2fs_count_used_clusters(ext2_filsys fs, blk64_t start,
+ blk64_t end, blk64_t *out)
+{
+ blk64_t next;
+ blk64_t tot_set = 0;
+ errcode_t retval;
+
+ while (start < end) {
+ retval = ext2fs_find_first_set_block_bitmap2(fs->block_map,
+ start, end, &next);
+ if (retval) {
+ if (retval == ENOENT)
+ retval = 0;
+ break;
+ }
+ start = next;
+
+ retval = ext2fs_find_first_zero_block_bitmap2(fs->block_map,
+ start, end, &next);
+ if (retval == 0) {
+ tot_set += next - start;
+ start = next + 1;
+ } else if (retval == ENOENT) {
+ retval = 0;
+ tot_set += end - start + 1;
+ break;
+ } else
+ break;
+ }
+
+ if (!retval)
+ *out = EXT2FS_NUM_B2C(fs, tot_set);
+ return retval;
+}
@@ -2914,6 +2914,8 @@ int main (int argc, char *argv[])
errcode_t retval = 0;
ext2_filsys fs;
badblocks_list bb_list = 0;
+ badblocks_iterate bb_iter;
+ blk_t blk;
unsigned int journal_blocks = 0;
unsigned int i, checkinterval;
int max_mnt_count;
@@ -2924,6 +2926,7 @@ int main (int argc, char *argv[])
char opt_string[40];
char *hash_alg_str;
int itable_zeroed = 0;
+ blk64_t overhead;
#ifdef ENABLE_NLS
setlocale(LC_MESSAGES, "");
@@ -3215,6 +3218,23 @@ int main (int argc, char *argv[])
if (!quiet)
printf("%s", _("done \n"));
+ /*
+ * Unmark bad blocks to calculate overhead, because metadata
+ * blocks and bad blocks can land on the same allocation cluster.
+ */
+ if (bb_list) {
+ retval = ext2fs_badblocks_list_iterate_begin(bb_list,
+ &bb_iter);
+ if (retval) {
+ com_err("ext2fs_badblocks_list_iterate_begin", retval,
+ "%s", _("while unmarking bad blocks"));
+ exit(1);
+ }
+ while (ext2fs_badblocks_list_iterate(bb_iter, &blk))
+ ext2fs_unmark_block_bitmap2(fs->block_map, blk);
+ ext2fs_badblocks_list_iterate_end(bb_iter);
+ }
+
retval = ext2fs_convert_subcluster_bitmap(fs, &fs->block_map);
if (retval) {
com_err(program_name, retval, "%s",
@@ -3222,6 +3242,28 @@ int main (int argc, char *argv[])
exit(1);
}
+ retval = ext2fs_count_used_clusters(fs, fs->super->s_first_data_block,
+ ext2fs_blocks_count(fs->super) - 1,
+ &overhead);
+ if (retval) {
+ com_err(program_name, retval, "%s",
+ _("while calculating overhead"));
+ exit(1);
+ }
+
+ if (bb_list) {
+ retval = ext2fs_badblocks_list_iterate_begin(bb_list,
+ &bb_iter);
+ if (retval) {
+ com_err("ext2fs_badblocks_list_iterate_begin", retval,
+ "%s", _("while marking bad blocks as used"));
+ exit(1);
+ }
+ while (ext2fs_badblocks_list_iterate(bb_iter, &blk))
+ ext2fs_mark_block_bitmap2(fs->block_map, blk);
+ ext2fs_badblocks_list_iterate_end(bb_iter);
+ }
+
if (super_only) {
check_plausibility(device_name, CHECK_FS_EXIST, NULL);
printf(_("%s may be further corrupted by superblock rewrite\n"),
@@ -3319,6 +3361,7 @@ int main (int argc, char *argv[])
free(journal_device);
} else if ((journal_size) ||
ext2fs_has_feature_journal(&fs_param)) {
+ overhead += EXT2FS_NUM_B2C(fs, journal_blocks);
if (super_only) {
printf("%s", _("Skipping journal creation in super-only mode\n"));
fs->super->s_journal_inum = EXT2_JOURNAL_INO;
@@ -3361,6 +3404,10 @@ no_journal:
fs->super->s_mmp_update_interval);
}
+ overhead += fs->super->s_first_data_block;
+ if (!super_only)
+ fs->super->s_overhead_clusters = overhead;
+
if (ext2fs_has_feature_bigalloc(&fs_param))
fix_cluster_bg_counts(fs);
if (ext2fs_has_feature_quota(&fs_param))
@@ -703,6 +703,7 @@ errcode_t adjust_fs_info(ext2_filsys fs, ext2_filsys old_fs,
double percent;
ext2fs_blocks_count_set(fs->super, new_size);
+ fs->super->s_overhead_clusters = 0;
retry:
fs->group_desc_count = ext2fs_div64_ceil(ext2fs_blocks_count(fs->super) -
If overhead is not recorded in the super block, it is caculated during mount in kernel, for bigalloc file systems the it takes O(groups**2) in time. For a 1PB deivce with 32K cluste size it takes ~12 mins to mount, with most of the time spent on figuring out overhead. While we can not improve the overhead algorithm in kernel due to the nature of bigalloc, we can work out the overhead during mke2fs and set it in the super block, avoiding calculating it every time when it mounts. Overhead is s_first_data_block plus internal journal blocks plus the block and inode bitmaps, inode table, super block backups and group descriptor blocks for every group. This patch introduces ext2fs_count_used_clusters(), which calculates the clusters used in the block bitmap for the given range. When bad blocks are involved, it gets tricky because the blocks counted as overhead and the bad blocks can end up in the same allocation cluster. In this case we will unmark the bad blocks from the block bitmap, convert to cluster bitmap and get the overhead, then mark the bad blocks back in the cluster bitmap. Reset the overhead to zero when resizing, we can not simplly count the used blocks as overhead like we do when mke2fs. The overhead can be calculated by kernel side during mount. Signed-off-by: Li Dongyang <dongyangli@ddn.com> --- lib/ext2fs/ext2fs.h | 2 ++ lib/ext2fs/gen_bitmap64.c | 35 +++++++++++++++++++++++++++++ misc/mke2fs.c | 47 +++++++++++++++++++++++++++++++++++++++ resize/resize2fs.c | 1 + 4 files changed, 85 insertions(+)