f2fs: improve searching speed of __next_free_blkoff

To find a zero bit using the result of OR operation between ckpt_valid_map
and cur_valid_map is more fast than find a zero bit in each bitmap.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
[Jaegeuk Kim: adjust changed function name]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
1 file changed