On Fri, Nov 12, 2021 at 04:37:19PM +0800, Ming Lei wrote: > > can only be used for reads, and no fua can be set if the preallocating > > I/O didn't use fua, etc. > > > > What are the pitfalls of just chanigng cmd_flags? > > Then we need to check cmd_flags carefully, such as hctx->type has to > be same, flush & passthrough flags has to be same, that said all > ->cmd_flags used for allocating rqs have to be same with the following > bio->bi_opf. > > In usual cases, I guess all IOs submitted from same plug batch should be > same type. If not, we can switch to change cmd_flags. Jens: is this a limit fitting into your use cases? I guess as a quick fix this rejecting different flags is probably the best we can do for now, but I suspect we'll want to eventually relax them.
