Is it safe to round-up offset and length to page boundary during
paging-read?
Thanks
Ramaraj
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Nick Ryan
Sent: Thursday, August 28, 2003 9:45 PM
To: File Systems Developers
Subject: [ntfsd] Re: Paging Write byte-range assumptions
Yes, you can assume the MDL is large enough… I know FastFat does.
Vipul wrote:
Hi Nick,
So, is it then safe to simply round-up the byte-count to next sector
boundary (and assume that the MDL is large enough), and proceed with
low-level write? Or should the FSD do the left-over sector zero-fill
etc…Thanks,
“Nick Ryan” wrote in message news:xxxxx@ntfsd…
>
>>For writes, the byte count can be non-aligned as long as the request
>>extends above valid data length. The offset must be aligned, however.
>>
>>Vipul wrote:
>>
>>
>>>Hi All,
>>>
>>>So, can there be a paging-write call to a FSD with a byte-range which is
>
> NOT
>
>>>page-aligned? Or, NOT even sector-aligned? The case we are running
>
> into is
>
>>>a memory-mapped write followed by FlushViewOfFile, which results in a
>>>paging-write with a arbitrary byte-range (which is not sector aligned).
>
> If
>
>>>this is true, then is it safe to simply round-up the range-end to the
>>>nearest sector, (and assume that the incoming buffer/MDL is large
>
> enough)?
>
>>>Also, what about paging-read? Or does that always happen for full-pages
>>>only.
>>>
>>>thanks,
>>>Vipul.
>>>
>>>
>>>
>>>
>>
>>–
>>Nick Ryan (MVP for DDK)
>>
>>
>>
>
>
>
>
>
–
Nick Ryan (MVP for DDK)
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