From: Yogita Bijani [yogita@iguard.com]
Sent: Wednesday, June 09, 1999 7:18 AM
To: ntfsd@atria.com; ntdev@atria.com
Subject: [ntfsd][ntdev] is there a limit to how many write requests can be handled at a time ?

Hi!
 
I am writing a filter driver below FSD which blocks write requests on one partition
for sometime and then releases it after a while. 
 
Following are the steps 
 
In IRP_MJ_WRITE handler
- IoMarkPending(Irp)
- queue IRP in a device Driver queue
- return STATUS_PENDING
 
In IRP_MJ_DEVICE_CONTROL handler
- On receiving a Control Code, send write request details to User Process
- On receiving another Control Code , dequeue the IRP and IoCallDriver()
 
I have posted this query before and after trying to investigate on each of the 
suggestions, I have come to this conclusion 

the user mode application is trying to write to a file on some other partition,
partition y, where I am not doing anything - no blocking , not even attaching to  
that partition.  But still the writes to a file on partition y are getting affected by my 
blocking writes on partition x.  
 
this leads to a deadlock and a system state which looks like a hang but actually it is 
only  the write requests which are getting blocked 
 
Same problem does not happen if instead of a file on partition y, the user application
is writing to a Volume itself ( using \\.\y: ) 

Any idea what could be the reason, what kind of limit is being reached, if any,  and
why doesn't it affect a Volume write ? 
 
Is it to do with some implementation details of ntfsd ?

waiting for suggestions, thanks a lot

yogita