Cache Purge

Hi falks,

This is my first question/message to this mailing
list, and I realy hope that somebody will help me.

I have a read-only file system driver (do not have
sources) atached to a ram-disk device. I’m making some
changes to the file system structure directly to
ram-disc device. How can I make the FS driver aware of
this changes and to recreate its metadata.

Is it possible to traverse every cached structure/
file for this FS driver and to purge the cache, so the
next time FS driver need to access this structure/file
it will reead it from the RAM-disc.

Thanks in advance

Greetings,
Nikola Gidalov
xxxxx@yahoo.com

=====
Nikola Gidalov
xxxxx@yahoo.com


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Nikola:

I’m confused. You wrote: “How can I make the FS driver aware of
this changes and to recreate its metadata.”
Are you writing a file system driver or file system filter driver?

Regads,

Vladimir

-----Original Message-----
From: Nikola Gidalov [mailto:xxxxx@yahoo.com]
Sent: Thursday, February 08, 2001 2:23 AM
To: File Systems Developers
Subject: [ntfsd] Cache Purge

Hi falks,

This is my first question/message to this mailing
list, and I realy hope that somebody will help me.

I have a read-only file system driver (do not have
sources) atached to a ram-disk device. I’m making some
changes to the file system structure directly to
ram-disc device. How can I make the FS driver aware of
this changes and to recreate its metadata.

Is it possible to traverse every cached structure/
file for this FS driver and to purge the cache, so the
next time FS driver need to access this structure/file
it will reead it from the RAM-disc.

Thanks in advance

Greetings,
Nikola Gidalov
xxxxx@yahoo.com

=====
Nikola Gidalov
xxxxx@yahoo.com


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Hi,

No, I’m not writing FS driver because I already have
one (read only). I make changes to ram-disc avoiding
the FDS (raw write). Now I wan to inform the FSD
atached to the ram-disk to be aware of my changes to
the underlying ram-disk.
I realy need HELP.

Thank you.

Nikola

-----Original Message-----

Nikola:

I’m confused. You wrote: “How can I make the FS
driver aware of
this changes and to recreate its metadata.”
Are you writing a file system driver or file system
filter driver?

Regads,

Vladimir

-----Original Message-----
From: Nikola Gidalov [mailto:xxxxx@yahoo.com]
Sent: Thursday, February 08, 2001 2:23 AM
To: File Systems Developers
Subject: [ntfsd] Cache Purge

Hi falks,

This is my first question/message to this mailing
list, and I realy hope that somebody will help me.

I have a read-only file system driver (do not have
sources) atached to a ram-disk device. I’m making some
changes to the file system structure directly to
ram-disc device. How can I make the FS driver aware of
this changes and to recreate its metadata.

Is it possible to traverse every cached structure/
file for this FS driver and to purge the cache, so the
next time FS driver need to access this structure/file
it will reead it from the RAM-disc.

Thanks in advance

Greetings,
Nikola Gidalov
xxxxx@yahoo.com

=====
Nikola Gidalov
xxxxx@yahoo.com


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Nikola:

Puting aside question about safety of that approach, it seems to me that you
realy have to purge cached data in all the outstanding FileObjects. If FSD
is “yours” you can walk through all its FileObjects and call
CcPurgeCacheSection for each of them.

Regards,

Vladimir

-----Original Message-----
From: Nikola Gidalov [mailto:xxxxx@yahoo.com]
Sent: Thursday, February 08, 2001 8:14 AM
To: File Systems Developers
Subject: [ntfsd] RE: Cache Purge

Hi,

No, I’m not writing FS driver because I already have
one (read only). I make changes to ram-disc avoiding
the FDS (raw write). Now I wan to inform the FSD
atached to the ram-disk to be aware of my changes to
the underlying ram-disk.
I realy need HELP.

Thank you.

Nikola

-----Original Message-----

Nikola:

I’m confused. You wrote: “How can I make the FS
driver aware of
this changes and to recreate its metadata.”
Are you writing a file system driver or file system
filter driver?

Regads,

Vladimir

-----Original Message-----
From: Nikola Gidalov [mailto:xxxxx@yahoo.com]
Sent: Thursday, February 08, 2001 2:23 AM
To: File Systems Developers
Subject: [ntfsd] Cache Purge

Hi falks,

This is my first question/message to this mailing
list, and I realy hope that somebody will help me.

I have a read-only file system driver (do not have
sources) atached to a ram-disk device. I’m making some
changes to the file system structure directly to
ram-disc device. How can I make the FS driver aware of
this changes and to recreate its metadata.

Is it possible to traverse every cached structure/
file for this FS driver and to purge the cache, so the
next time FS driver need to access this structure/file
it will reead it from the RAM-disc.

Thanks in advance

Greetings,
Nikola Gidalov
xxxxx@yahoo.com

=====
Nikola Gidalov
xxxxx@yahoo.com


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… which will work up until the point the changes you make cause open
objects to be invalid.

You want to sit down and understand the verify path of the CDFS and
especially FASTFAT samples in the IFS Kit. You are talking about a case
which is the equivalent of removeable media like a floppy being removed
and coming back, arbitrarily modified. There are two fundamental
mechanisms:

  • set the DO_VERIFY_VOLUME flag on the target device the filesystem
    mounted
  • implement the IOCTL_DISK/CDROM/STORAGE_CHECK_VERIFY so the FS can
    realize the underlying storage has changed

This works for FAT, CDFS, UDFS. It does not for NTFS - by design it does
not work on non-lockable removeable media, and it does not permit media
eject without tearing down and remounting the entire volume
(dismounting).

-----Original Message-----
From: Chtchetkine, Vladimir [mailto:xxxxx@Starbase.com]
Sent: Thursday, February 08, 2001 8:25 AM
To: File Systems Developers
Subject: [ntfsd] RE: Cache Purge

Nikola:

Puting aside question about safety of that approach, it seems to me that
you realy have to purge cached data in all the outstanding FileObjects.
If FSD is “yours” you can walk through all its FileObjects and call
CcPurgeCacheSection for each of them.

Regards,

Vladimir

-----Original Message-----
From: Nikola Gidalov [mailto:xxxxx@yahoo.com]
Sent: Thursday, February 08, 2001 8:14 AM
To: File Systems Developers
Subject: [ntfsd] RE: Cache Purge

Hi,

No, I’m not writing FS driver because I already have
one (read only). I make changes to ram-disc avoiding
the FDS (raw write). Now I wan to inform the FSD
atached to the ram-disk to be aware of my changes to
the underlying ram-disk.
I realy need HELP.

Thank you.

Nikola

-----Original Message-----

Nikola:

I’m confused. You wrote: “How can I make the FS
driver aware of
this changes and to recreate its metadata.”
Are you writing a file system driver or file system
filter driver?

Regads,

Vladimir

-----Original Message-----
From: Nikola Gidalov [mailto:xxxxx@yahoo.com]
Sent: Thursday, February 08, 2001 2:23 AM
To: File Systems Developers
Subject: [ntfsd] Cache Purge

Hi falks,

This is my first question/message to this mailing
list, and I realy hope that somebody will help me.

I have a read-only file system driver (do not have
sources) atached to a ram-disk device. I’m making some
changes to the file system structure directly to
ram-disc device. How can I make the FS driver aware of
this changes and to recreate its metadata.

Is it possible to traverse every cached structure/
file for this FS driver and to purge the cache, so the
next time FS driver need to access this structure/file
it will reead it from the RAM-disc.

Thanks in advance

Greetings,
Nikola Gidalov
xxxxx@yahoo.com

=====
Nikola Gidalov
xxxxx@yahoo.com


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It is not safe to modify the data from under the FSD, in fact, I’d be
surprised if it let you. You should send the FSD an unmount ioctl request
to get it to unmount the filesystem, and lock it so you have exclusive
access to it while you make changes. Then unlock it and the filesystem
will remount it when needed.

At 02:22 AM 2/8/01 -0800, you wrote:

Hi falks,

This is my first question/message to this mailing
list, and I realy hope that somebody will help me.

I have a read-only file system driver (do not have
sources) atached to a ram-disk device. I’m making some
changes to the file system structure directly to
ram-disc device. How can I make the FS driver aware of
this changes and to recreate its metadata.

Is it possible to traverse every cached structure/
file for this FS driver and to purge the cache, so the
next time FS driver need to access this structure/file
it will reead it from the RAM-disc.

Thanks in advance

Greetings,
Nikola Gidalov
xxxxx@yahoo.com


You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com