From owner-freebsd-hackers  Mon Aug 21 18:07:20 1995
Return-Path: hackers-owner
Received: (from majordom@localhost)
          by freefall.FreeBSD.org (8.6.11/8.6.6) id SAA22918
          for hackers-outgoing; Mon, 21 Aug 1995 18:07:20 -0700
Received: from cs.weber.edu (cs.weber.edu [137.190.16.16])
          by freefall.FreeBSD.org (8.6.11/8.6.6) with SMTP id SAA22912
          ; Mon, 21 Aug 1995 18:07:19 -0700
Received: by cs.weber.edu (4.1/SMI-4.1.1)
	id AA27924; Mon, 21 Aug 95 19:08:59 MDT
From: terry@cs.weber.edu (Terry Lambert)
Message-Id: <9508220108.AA27924@cs.weber.edu>
Subject: Changing DEV_BSIZE
To: hackers@freebsd.org, curent@freebsd.org
Date: Mon, 21 Aug 95 19:08:58 MDT
X-Mailer: ELM [version 2.4dev PL52]
Sender: hackers-owner@freebsd.org
Precedence: bulk

Oops!  Sent that one without a message body!  8-).


I want to up the size of DIRBLKSIZE in ufs/ufs/dir.h to play around
with some things I was playing around with before the VM changes.

The dir.h code says that the DIR_BLKSIZ needs to be DEV_BSIZE to
make any atomicity guarantees... this wasn't the case in the
previous code.

I'd like to know if making the DIRBLKSIZ 1204 (ie: DEV_BSIZE * 2)
will result in problems.  It seems to me that the disks are accessed
in terms of pages in any case, and the comment in dir.h that says:

 * A directory consists of some number of blocks of DIRBLKSIZ
 * bytes, where DIRBLKSIZ is chosen such that it can be transferred
 * to disk in a single atomic operation (e.g. 512 bytes on most machines).

Is in fact outdated and incorrect -- even on older pre-VM changes
code, I'd think...

Does anyone see a problem with this?  Note that I'm not proposing
this change for the generic case of everyone's UFS... just mine.


If there *is* a 512 byte limit in effect here, can I up DEV_BSIZE
to get around it?

Is this just artificial crap to deal with frags?


					Terry Lambert
					terry@cs.weber.edu
---
Any opinions in this posting are my own and not those of my present
or previous employers.