File Virtualization using minifilter

NTFSD
1

Hi ,

I’m trying to implement a simple “file virtualization” using minifilter ,or simply rename the file during the pre-operation callback (e.g - if the app tries to open "C:\docs\test.txt i’d like to open the “C:\temp\docs\test.txt” instead…)

At first,I tought that I can simply change the FileName member of “Data->Iopb->TargetFileObject” , but i think that it’s not safe since the buffer is cached by the filter-manager (thus other minifilter can still use the old buffer and it’s risky)

My second thought was to replace the FileObject with my new FileObject, but i’m afraid that it’s even more risky (since it’s not documented elsewhere)

Am I missing something ? which method should i use ? how does MS implement the (Vista) minifilter file virtualization ?

tnx,
zvika

2

Search the ntfsd archives for STATUS_REPARSE and the wdk for
fltsetcallbackdatadirty.

m.

ferents@cs.bgu.ac.il wrote:

Hi ,

I’m trying to implement a simple “file virtualization” using minifilter ,or simply rename the file during the pre-operation callback (e.g - if the app tries to open "C:\docs\test.txt i’d like to open the “C:\temp\docs\test.txt” instead…)

At first,I tought that I can simply change the FileName member of “Data->Iopb->TargetFileObject” , but i think that it’s not safe since the buffer is cached by the filter-manager (thus other minifilter can still use the old buffer and it’s risky)

My second thought was to replace the FileObject with my new FileObject, but i’m afraid that it’s even more risky (since it’s not documented elsewhere)

Am I missing something ? which method should i use ? how does MS implement the (Vista) minifilter file virtualization ?

tnx,
zvika

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

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3

ferents@cs.bgu.ac.il wrote:

Hi ,

I’m trying to implement a simple “file virtualization” using minifilter ,or simply rename the file during the pre-operation callback (e.g - if the app tries to open "C:\docs\test.txt i’d like to open the “C:\temp\docs\test.txt” instead…)

At first,I tought that I can simply change the FileName member of “Data->Iopb->TargetFileObject” , but i think that it’s not safe since the buffer is cached by the filter-manager (thus other minifilter can still use the old buffer and it’s risky)

My second thought was to replace the FileObject with my new FileObject, but i’m afraid that it’s even more risky (since it’s not documented elsewhere)

Am I missing something ? which method should i use ? how does MS implement the (Vista) minifilter file virtualization ?

Hi,

you shall try to use STATUS_REPARSE,

Sandor LUKACS

tnx,
zvika

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

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