Nice to meet you.
I will post a question for your help.
I have been developing a caching module now
and facing a big design problem related to handling REQ_FUA flag.
Suppose we have 4KB split_io and
the original bio is 8KB with REQ_FUA flag.
The device-mapper dm_request function now
splits the original one into two 4KB sized bios with REQ_FUA and
then passes them to map function one by one.
This eventually leads to inefficient code in my case.
All I want to do is flushing the preceding split bios at last but
I know that is not always the most efficient implementation in any dm modules and
that's why device-mapper is what it is like now.
My question is
Is there any mean to know the second bio split is the last one in the split sequence?
I need your help.