when overwrite only first block of cluster, since cluster is not full, it
will call f2fs_write_raw_pages when f2fs_write_multi_pages, and cause the
whole cluster become uncompressed eventhough data can be compressed.
this may will make random write bench score reduce a lot.
root# dd if=/dev/zero of=./fio-test bs=1M count=1
root# sync
root# echo 3 > /proc/sys/vm/drop_caches
root# f2fs_io get_cblocks ./fio-test
root# dd if=/dev/zero of=./fio-test bs=4K count=1 oflag=direct conv=notrunc
w/o patch:
root# f2fs_io get_cblocks ./fio-test
189
w/ patch:
root# f2fs_io get_cblocks ./fio-test
192
Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
b368cc5e26