When writing a file, a fastio write request can be brought firstly ?

NTFSD
1

When writing a file, a fastio write request can be brought firstly before
any IRP_MJ_WRITE IRP is brought ?

2

Another question : When writing a file, I find that the first write-request
is always NOT a PAGEIO IRP . This is certain ?
Why ?
“Leo” wrote in message news:xxxxx@ntfsd…
> When writing a file, a fastio write request can be brought firstly before
> any IRP_MJ_WRITE IRP is brought ?
>
>

3

You will see the first IO request as paging io only in scenario where the
file is memory mapped. If the file is not memory mapped then you will see a
paging io reqeust for a file only after the caching has been initialized by
the fsd for that file. Fsds generally initialize caching whenever a first io
request is sent for a particular file.

To answer your previous question IoManager calls the fast io only for the
files which have been opened for synchronous IO and caching has already been
enabled. What this means is that the first IO request cannot be fast io
request since caching is initialized only when the first io request is
handled.

thanks
-Kiran
“Leo” wrote in message news:xxxxx@ntfsd…
> Another question : When writing a file, I find that the first
> write-request is always NOT a PAGEIO IRP . This is certain ?
> Why ?
> “Leo” wrote in message news:xxxxx@ntfsd…
>> When writing a file, a fastio write request can be brought firstly before
>> any IRP_MJ_WRITE IRP is brought ?
>>
>>
>
>
>

4

Thanks!

“Kiran Joshi” wrote in message news:xxxxx@ntfsd…
> You will see the first IO request as paging io only in scenario where the
> file is memory mapped. If the file is not memory mapped then you will see
> a paging io reqeust for a file only after the caching has been initialized
> by the fsd for that file. Fsds generally initialize caching whenever a
> first io request is sent for a particular file.
>
> To answer your previous question IoManager calls the fast io only for the
> files which have been opened for synchronous IO and caching has already
> been enabled. What this means is that the first IO request cannot be fast
> io request since caching is initialized only when the first io request is
> handled.
>
> thanks
> -Kiran
> “Leo” wrote in message news:xxxxx@ntfsd…
>> Another question : When writing a file, I find that the first
>> write-request is always NOT a PAGEIO IRP . This is certain ?
>> Why ?
>> “Leo” wrote in message news:xxxxx@ntfsd…
>>> When writing a file, a fastio write request can be brought firstly
>>> before any IRP_MJ_WRITE IRP is brought ?
>>>
>>>
>>
>>
>>
>
>
>