Feeling really stupid asking this, but how do we identify cached io in read/write callbacks ?
We can set flag to skip cached io during registration but I haven’t found flag that identifies cached io operation in callback data
I thought that flt_is_fastio_operation macros can be used for that.
But now rereading Nagar’s book and he says that irp operation also can be completed by cache manager
You want to look at Data->Iopb->IrpFlags I’m not well connected to the internet right now but the flags are something like IRP_PAGING IRP_NOCACHE . If neither are set then it’s cached.
Fastio is sort of orthogonal (non cached io cannot be completed in the fastio path, but non buffered io can be sent down that path…