MJ_WRITE (newbie's question)

NTFSD
1

hi, all
How to get the length of the user data to be written in mj_write
dispatch routine? When i use notepad.exe to open a file, it seems that the
Irp.Parameters.Write.Length is always 4096(am i wrong?).But the actual data
written to the file is less than it. So how to get the length of the actual
data.
Any help will be appreciated.

Sorry for my pool English.
Thanks!

2

4k pages when the cache manager is doing I/O; unless you open the file
specifying no caching.

Jamey

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Jacky
Sent: Sunday, May 30, 2004 6:05 PM
To: Windows File Systems Devs Interest List
Subject: [ntfsd] MJ_WRITE (newbie’s question)

hi, all
How to get the length of the user data to be written in mj_write
dispatch routine? When i use notepad.exe to open a file, it seems that the
Irp.Parameters.Write.Length is always 4096(am i wrong?).But the actual data
written to the file is less than it. So how to get the length of the actual
data.
Any help will be appreciated.

Sorry for my pool English.
Thanks!

Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17

You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

3

Correct. Notepad uses memory-mapped file.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

----- Original Message -----
From: “Jacky”
Newsgroups: ntfsd
To: “Windows File Systems Devs Interest List”
Sent: Monday, May 31, 2004 5:05 AM
Subject: [ntfsd] MJ_WRITE (newbie’s question)

> hi, all
> How to get the length of the user data to be written in mj_write
> dispatch routine? When i use notepad.exe to open a file, it seems that the
> Irp.Parameters.Write.Length is always 4096(am i wrong?).But the actual data
> written to the file is less than it. So how to get the length of the actual
> data.
> Any help will be appreciated.
>
> Sorry for my pool English.
> Thanks!
>
>
>
>
>
> —
> Questions? First check the IFS FAQ at
https://www.osronline.com/article.cfm?id=17
>
> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com

4

thanks, Jamey
so for general purpose, how to get the actual length when write data to a
file.

“Jamey Kirby” ??? news:xxxxx@ntfsd…
> 4k pages when the cache manager is doing I/O; unless you open the file
> specifying no caching.
>
> Jamey
>
>
> -----Original Message-----
> From: xxxxx@lists.osr.com
> [mailto:xxxxx@lists.osr.com] On Behalf Of Jacky
> Sent: Sunday, May 30, 2004 6:05 PM
> To: Windows File Systems Devs Interest List
> Subject: [ntfsd] MJ_WRITE (newbie’s question)
>
> hi, all
> How to get the length of the user data to be written in mj_write
> dispatch routine? When i use notepad.exe to open a file, it seems that the
> Irp.Parameters.Write.Length is always 4096(am i wrong?).But the actual
data
> written to the file is less than it. So how to get the length of the
actual
> data.
> Any help will be appreciated.
>
> Sorry for my pool English.
> Thanks!
>
>
>
>
>
> —
> Questions? First check the IFS FAQ at
> https://www.osronline.com/article.cfm?id=17
>
> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to xxxxx@lists.osr.com
>
>

5

thank you, Maxim

“Maxim S. Shatskih” ??? news:xxxxx@ntfsd…
> Correct. Notepad uses memory-mapped file.
>
> Maxim Shatskih, Windows DDK MVP
> StorageCraft Corporation
> xxxxx@storagecraft.com
> http://www.storagecraft.com
>
>
> ----- Original Message -----
> From: “Jacky”
> Newsgroups: ntfsd
> To: “Windows File Systems Devs Interest List”
> Sent: Monday, May 31, 2004 5:05 AM
> Subject: [ntfsd] MJ_WRITE (newbie’s question)
>
>
> > hi, all
> > How to get the length of the user data to be written in mj_write
> > dispatch routine? When i use notepad.exe to open a file, it seems that
the
> > Irp.Parameters.Write.Length is always 4096(am i wrong?).But the actual
data
> > written to the file is less than it. So how to get the length of the
actual
> > data.
> > Any help will be appreciated.
> >
> > Sorry for my pool English.
> > Thanks!
> >
> >
> >
> >
> >
> > —
> > Questions? First check the IFS FAQ at
> https://www.osronline.com/article.cfm?id=17
> >
> > You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> > To unsubscribe send a blank email to xxxxx@lists.osr.com
>
>