On Thu, Nov 04, 2021 at 10:32:35AM -0700, Darrick J. Wong wrote:

I also wonder if it would be useful (since we're already having a
discussion elsewhere about data integrity syscalls for pmem) to be able
to call this sort of thing against files?  In which case we'd want
another preadv2 flag or something, and then plumb all that through the
vfs/iomap as needed?

IFF we do this (can't answer if there is a need) we should not
overload read with it.  It is an operation that does not return
data but just a status, so let's not get into that mess.