Subject: Re: vnd, VOP_ and encrypted fs.
To: Artur Grabowski <>
From: Jason R Thorpe <>
List: tech-kern
Date: 10/31/2001 07:58:40
On Wed, Oct 31, 2001 at 11:08:33AM +0100, Artur Grabowski wrote:

 > Jorgen Lundman <> writes:
 > > To which they have an "if vndsimple(bp->b_dec)) { " to test whether or
 > > not it should use the new method. (Which appears to be an &0x80 test).
 > The man-page usually helps.
 >      "There are two variants, the traditional vnd that
 >      bypasses the buffercache and thus is suitable for swap on files, but not
 >      for building disk-images, and the svnd ("safe" vnd ) variant that goes
 >      through the buffercache, thereby maintaining cache-coherency after the
 >      block-device is closed which makes it suitable for creating disk images.
 >      The latter is not good for swapping on, though."

There is no need for this change in NetBSD, of course.  NetBSD's vnd fixed
the two-layer coherency problem a different way quite some time ago.

        -- Jason R. Thorpe <>