non cached writes in minifilters

NTFSD
1

Hi,
Are non cached and paging io request that come to a minifilter always
sector-size aligned?
If yes who ensures this (ie the io manager or some other component) ?

Thanks,

Dhirendra Kumar

2

On Tue, Mar 1, 2011 at 4:57 PM, DHIRENDRA ram wrote:

> Hi,
> Are non cached and paging io request that come to a minifilter always
> sector-size aligned?
> If yes who ensures this (ie the io manager or some other component) ?
>
> Thanks,
>
> Dhirendra Kumar
>

I have read this in previous threads but when I checked this in my
minifilter driver I found that the writelen is equal to size requested by
the application which may not necessarily be multiple of sector size.

3

Non-cached requests that are NOT paging I/O are always sector aligned.
Paging I/O requests on the other hand are always sector aligned for read
request but may not be sector aligned for the write request if it is for the
last portion in the file.

Regards,

Ayush Gupta

Software Consultant & Owner,

AI Consulting

From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of DHIRENDRA ram
Sent: Tuesday, March 01, 2011 4:57 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] non cached writes in minifilters

Hi,
Are non cached and paging io request that come to a minifilter always
sector-size aligned?
If yes who ensures this (ie the io manager or some other component) ?

Thanks,

Dhirendra Kumar
— NTFSD is sponsored by OSR For our schedule of debugging and file system
seminars visit: http://www.osr.com/seminars To unsubscribe, visit the List
Server section of OSR Online at
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4

On 3/1/2011 4:45 AM, Ayush Gupta wrote:

Non-cached requests that are NOT paging I/O are always sector aligned.
Paging I/O requests on the other hand are always sector aligned for read
request but may not be sector aligned for the write request if it is for
the last portion in the file.

To clarify, the starting offset is always sector aligned but the length
may not be.

Pete

Regards,

Ayush Gupta

Software Consultant & Owner,

AI Consulting

*From:*xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] *On Behalf Of *DHIRENDRA ram
*Sent:* Tuesday, March 01, 2011 4:57 PM
*To:* Windows File Systems Devs Interest List
*Subject:* [ntfsd] non cached writes in minifilters

Hi,
Are non cached and paging io request that come to a minifilter always
sector-size aligned?
If yes who ensures this (ie the io manager or some other component) ?

Thanks,

Dhirendra Kumar
— NTFSD is sponsored by OSR For our schedule of debugging and file
system seminars visit: http://www.osr.com/seminars To unsubscribe, visit
the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer

NTFSD is sponsored by OSR

For our schedule of debugging and file system seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer

–
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