Tunnel cache

NTFSD
1

Hi. All.

I have some questions about tunnel cache and it’s operations.

  1. Tunnel cache is used for a name information only. (LFN, SFN)
    Or tunnel cache maintains content of a file and updates it at some case(if needed). what is right?
  2. if the last case is right, then it uses different stream(or file) with origin file (different FsContext). is it right? (uses special functions, so doesn’t appear in CREATE, CLOSE etc.)
  3. if the #2 right, Is it possible that a filter catchs the update operations threat with a standard Non-cached and paging i/o anyway?

thanks in advances.

2

Tunnel cache is used for caching for a small time and in a keyed manner file names. It wont modify the content fo your file at all. Tunnel caches are not even mandatory to be implemented by a file system.

----- Original Message -----
From: gyver-park
To: File Systems Developers
Sent: Friday, August 09, 2002 5:33 PM
Subject: [ntfsd] Tunnel cache

Hi. All.

I have some questions about tunnel cache and it’s operations.

  1. Tunnel cache is used for a name information only. (LFN, SFN)
    Or tunnel cache maintains content of a file and updates it at some case(if needed). what is right?
  2. if the last case is right, then it uses different stream(or file) with origin file (different FsContext). is it right? (uses special functions, so doesn’t appear in CREATE, CLOSE etc.)
  3. if the #2 right, Is it possible that a filter catchs the update operations threat with a standard Non-cached and paging i/o anyway?

thanks in advances.

b???v?j??ʢN???zǧu?jy???j???vBX???&

3

The Tunnel Cache is used for meta-data (names, timestamps) but not for the
contents of the file. For example, a text editor might rename the EXISTING
file (foo.doc to foo.bak) and then create a NEW file (foo.doc). The tunnel
cache can restore the short and long file name and the timestamps of the
original file (or any other information the FSD wishes to associate with
the old file.)

Regards,

Tony

Tony Mason

Consulting Partner

OSR Open Systems Resources, Inc.

http: http://www.osr.com

Hope to see you at the next OSR file systems class in San Jose, CA
September 16, 2002!

-----Original Message-----
From: gyver-park [mailto:xxxxx@jlandsoft.com]
Sent: Friday, August 09, 2002 10:34 AM
To: File Systems Developers
Subject: [ntfsd] Tunnel cache

Hi. All.

I have some questions about tunnel cache and it’s operations.

1. Tunnel cache is used for a name information only. (LFN, SFN)

Or tunnel cache maintains content of a file and updates it at some
case(if needed). what is right?

2. if the last case is right, then it uses different stream(or file) with
origin file (different FsContext). is it right? (uses special functions, so
doesn’t appear in CREATE, CLOSE etc.)

3. if the #2 right, Is it possible that a filter catchs the update
operations threat with a standard Non-cached and paging i/o anyway?

thanks in advances.

b???.???????&??'??j???(?:.?˛???m??֛???zf???%y?ޞ???l??</http:>

4

Thank you very much.
Dan and Tony.

----- Original Message -----
From: “Tony Mason”
To: “File Systems Developers”
Sent: Saturday, August 10, 2002 12:12 AM
Subject: [ntfsd] RE: Tunnel cache

The Tunnel Cache is used for meta-data (names, timestamps) but not for the
contents of the file. For example, a text editor might rename the EXISTING
file (foo.doc to foo.bak) and then create a NEW file (foo.doc). The tunnel
cache can restore the short and long file name and the timestamps of the
original file (or any other information the FSD wishes to associate with
the old file.)

Regards,

5

Tunnel cache contains only the name and the FS-specific “dirent location” information.
For FAT, it speeds up the sequence of “delete a file, then re-create the file with the same name”.

Without the tunnel, FASTFAT would need to scan the directory for a free slot. With the tunnel, FASTFAT already knows the free slot location.

Max
----- Original Message -----
From: gyver-park
To: File Systems Developers
Sent: Friday, August 09, 2002 6:33 PM
Subject: [ntfsd] Tunnel cache

Hi. All.

I have some questions about tunnel cache and it’s operations.

  1. Tunnel cache is used for a name information only. (LFN, SFN)
    Or tunnel cache maintains content of a file and updates it at some case(if needed). what is right?
  2. if the last case is right, then it uses different stream(or file) with origin file (different FsContext). is it right? (uses special functions, so doesn’t appear in CREATE, CLOSE etc.)
  3. if the #2 right, Is it possible that a filter catchs the update operations threat with a standard Non-cached and paging i/o anyway?

thanks in advances.

b???v?jƶ?i?d??{.n???zwZnV???h???z{_?ݴ?p%??l??

6

No.

I’m not sure how you read that out of the source. You might be confusing two seperate trains of code together, but the tunnel cache certainly has nothing to do with directory entry allocation.

-----Original Message-----
From: Maxim S. Shatskih [mailto:xxxxx@storagecraft.com]
Sent: Sat 8/10/2002 2:48 AM
To: File Systems Developers
Cc:
Subject: [ntfsd] Re: Tunnel cache

Tunnel cache contains only the name and the FS-specific “dirent location” information.
For FAT, it speeds up the sequence of “delete a file, then re-create the file with the same name”.

Without the tunnel, FASTFAT would need to scan the directory for a free slot. With the tunnel, FASTFAT already knows the free slot location.

Max

----- Original Message -----
From: gyver-park mailto:xxxxx
To: File Systems Developers mailto:xxxxx
Sent: Friday, August 09, 2002 6:33 PM
Subject: [ntfsd] Tunnel cache

Hi. All.

I have some questions about tunnel cache and it’s operations.

1. Tunnel cache is used for a name information only. (LFN, SFN)
Or tunnel cache maintains content of a file and updates it at some case(if needed). what is right?
2. if the last case is right, then it uses different stream(or file) with origin file (different FsContext). is it right? (uses special functions, so doesn’t appear in CREATE, CLOSE etc.)
3. if the #2 right, Is it possible that a filter catchs the update operations threat with a standard Non-cached and paging i/o anyway?

thanks in advances.

b?떴췾탂틋걁줰翁{.n?돴촾wZnV쭛??h뺞칬{_금닦p%듚l▧

—
You are currently subscribed to ntfsd as: xxxxx@windows.microsoft.com
To unsubscribe send a blank email to xxxxx@lists.osr.com</mailto:xxxxx></mailto:xxxxx>

7

> I’m not sure how you read that out of the source. You might be
confusing two seperate trains

of code together, but the tunnel cache certainly has nothing to do
with directory entry
allocation.

Yes. I’m sorry.
Tunnel seem to keep creation time + 8.3 name for the just-deleted
dirents, so that the new dirent created with the same name will
inherit them.

Also the IFS Kit help tells that tunnel cache is used for Filename
Aliases on FAT.

Max