question about IoGetTopLevelIrp

NTFSD
1

One of the rules for file system filter driver is:
“Don¡¯t issue file system calls if IoGetTopLevelIrp() returns a non-NULL
value since it could cause system deadlock or overflow the stack”
Could anybody explain it a bit to me? How does the deadlock be hit?

–

Best Regards,
hanzhu

2

Search this group at the osronline website …

“hanzhu” wrote in message news:xxxxx@ntfsd…
> One of the rules for file system filter driver is:
> “Don¡¯t issue file system calls if IoGetTopLevelIrp() returns a non-NULL
> value since it could cause system deadlock or overflow the stack”
> Could anybody explain it a bit to me? How does the deadlock be hit?
>
> –
>
> _______________________________________________________
> Best Regards,
> hanzhu
>
>

3

For those unfamiliar with search tools like Google, the key here is to
specify both the search term and the site. For example if I enter
“TopLevleIrp site:osronline.com” it will restrict the results to OSR
Online:

http://www.google.com/search?hl=en&lr=&q=TopLevelIrp+site%3Aosronline.co
m&btnG=Search

Is the link to the search I performed using the above string with
Google. Almost everything being asked in the forum these days has been
asked and answered previously (especially basic issues like “what is a
deadlock and why would I observe one in a massively reentrant system
like a Windows file system.”)

Regards,

Tony

Tony Mason
Consulting Partner
OSR Open Systems Resources, Inc.
http://www.osr.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of hanzhu
Sent: Tuesday, September 26, 2006 8:27 AM
To: ntfsd redirect
Subject: [ntfsd] question about IoGetTopLevelIrp

One of the rules for file system filter driver is:
“Don’t issue file system calls if IoGetTopLevelIrp() returns a non-NULL
value since it could cause system deadlock or overflow the stack”
Could anybody explain it a bit to me? How does the deadlock be hit?

–

Best Regards,
hanzhu

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

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4

> For those unfamiliar with search tools like Google, the key here is to

specify both the search term and the site. For example if I enter
“TopLevleIrp site:osronline.com” it will restrict the results to OSR

ROFL !
Amen on that :slight_smile:

L.