Windows System Software -- Consulting, Training, Development -- Unique Expertise, Guaranteed Results

Before Posting...
Please check out the Community Guidelines in the Announcements and Administration Category.

How to identify cached io ?

Sergey_PisarevSergey_Pisarev Member - All Emails Posts: 156

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


  • Sergey_PisarevSergey_Pisarev Member - All Emails Posts: 156

    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

  • rod_widdowsonrod_widdowson Member - All Emails Posts: 1,081

    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....

Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Upcoming OSR Seminars
Writing WDF Drivers 21 Oct 2019 OSR Seminar Space & ONLINE
Internals & Software Drivers 18 Nov 2019 Dulles, VA
Kernel Debugging 30 Mar 2020 OSR Seminar Space
Developing Minifilters 27 Apr 2020 OSR Seminar Space & ONLINE