with the changes in 5.8, writeboost will be broken.
In file included from ./include/linux/device-mapper.h:12,
from /home/akira/dm-writeboost/src/dm-writeboost.h:36,
from /home/akira/dm-writeboost/src/dm-writeboost-daemon.c:20:
./include/linux/blkdev.h:1236:5: note: declared here
int blkdev_issue_flush(struct block_device *, gfp_t);
^~~~~~~~~~~~~~~~~~
https://github.com/torvalds/linux/commit/9398554fb3979852512ff4f1405e759889b45c16#diff-6270799ef495960f0a896659ea4cdaa0
with the changes in 5.8, writeboost will be broken.