Re: kern/38717: sysinst shouldn't create LFS file systems

[Alan Barrett <apb%cequrux.com@localhost>]

The following reply was made to PR kern/38717; it has been noted by GNATS.

From: Alan Barrett <apb%cequrux.com@localhost>
To: gnats-bugs%NetBSD.org@localhost, netbsd-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/38717: sysinst shouldn't create LFS file systems
Date: Wed, 11 Jun 2008 22:54:30 +0200

 On Wed, 11 Jun 2008, David Holland wrote:
 > Well, what happens is that block pointers get updated synchronously
 > without the data they point to having been written out; so if you
 > crash you can get whatever crap was on the disk in that location
 > previously.
 
 Yes.  I had incorrectly thought that the random content that I saw was
 in files that had been modified in place, but I now know that they were
 in files that had been newly created and renamed, so your description
 matches what I saw.
 
 >  > >  > ffs with -o async [...]
 >  > > ... cannot reasonably be expected to work.
 > 
 > Crashing is a bug, yes. I read what you wrote as meaning that the fs
 > corruption after a crash was even worse, though; that is to be
 > expected. (IME, crashes with ffs -o async are often unrecoverable.)
 
 When I said "ffs with -o async is even worse", I meant "leads to a
 guaranteed system crash much more quickly [than ffs without -o async]".
 
 --apb (Alan Barrett)