For a bigalloc filesystem, converting the block bitmap from blocks
to chunks in ext2fs_convert_subcluster_bitmap() can take a long time
when the device is huge, because we test the bitmap
bit-by-bit using ext2fs_test_block_bitmap2().
Use ext2fs_find_first_set_block_bitmap2() which is more efficient
for mke2fs when the fs is mostly empty.
e2fsck can also benifit from this during pass1 block scanning.
Time taken for "mke2fs -O bigalloc,extent -C 131072 -b 4096" on a 1PB
device:
without patch:
real 27m49.457s
user 21m36.474s
sys 6m9.514s
with patch:
real 6m31.908s
user 0m1.806s
sys 6m29.697s
Signed-off-by: Li Dongyang <dongyangli@xxxxxxx>
---
lib/ext2fs/gen_bitmap64.c | 21 +++++++++------------
1 file changed, 9 insertions(+), 12 deletions(-)
diff --git a/lib/ext2fs/gen_bitmap64.c b/lib/ext2fs/gen_bitmap64.c
index 6e4d8b71..97601232 100644
--- a/lib/ext2fs/gen_bitmap64.c
+++ b/lib/ext2fs/gen_bitmap64.c
@@ -28,6 +28,7 @@
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
+#include <sys/param.h>
#include "ext2_fs.h"
#include "ext2fsP.h"
@@ -799,8 +800,8 @@ errcode_t ext2fs_convert_subcluster_bitmap(ext2_filsys fs,
ext2fs_generic_bitmap_64 bmap, cmap;
ext2fs_block_bitmap gen_bmap = *bitmap, gen_cmap;
errcode_t retval;
- blk64_t i, b_end, c_end;
- int n, ratio;
+ blk64_t i, next, b_end, c_end;
+ int ratio;
bmap = (ext2fs_generic_bitmap_64) gen_bmap;
if (fs->cluster_ratio_bits == ext2fs_get_bitmap_granularity(gen_bmap))
@@ -817,18 +818,14 @@ errcode_t ext2fs_convert_subcluster_bitmap(ext2_filsys fs,
bmap->end = bmap->real_end;
c_end = cmap->end;
cmap->end = cmap->real_end;
- n = 0;
ratio = 1 << fs->cluster_ratio_bits;
while (i < bmap->real_end) {
- if (ext2fs_test_block_bitmap2(gen_bmap, i)) {
- ext2fs_mark_block_bitmap2(gen_cmap, i);
- i += ratio - n;
- n = 0;
- continue;
- }
- i++; n++;
- if (n >= ratio)
- n = 0;
+ retval = ext2fs_find_first_set_block_bitmap2(gen_bmap,
+ i, bmap->real_end, &next);
+ if (retval)
+ break;
+ ext2fs_mark_block_bitmap2(gen_cmap, next);
+ i = bmap->start + roundup(next - bmap->start + 1, ratio);
}
bmap->end = b_end;
cmap->end = c_end;
--
2.22.1
