Re: kern/37955: Kernel Panic NetBSD 4.0 blkfree

[David Holland <dholland-bugs%netbsd.org@localhost>]

The following reply was made to PR kern/37955; it has been noted by GNATS.

From: David Holland <dholland-bugs%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
        netbsd-bugs%netbsd.org@localhost, vlvdberg%mijnpostvak.in@localhost
Subject: Re: kern/37955: Kernel Panic NetBSD 4.0 blkfree
Date: Mon, 10 Mar 2008 10:24:48 +0000

 On Wed, Mar 05, 2008 at 12:00:05PM +0000, Vincent van den Berg wrote:
  > From: Vincent van den Berg <vincent%mijnpostvak.in@localhost>
  > To: gnats-bugs%NetBSD.org@localhost
  > Subject: Re: kern/37955: Kernel Panic NetBSD 4.0 blkfree
  > Date: Wed, 05 Mar 2008 12:56:59 +0100
  > 
  >  It just happened again, with a clean file system while using rsnapshot! 
  >  I think this is a serious bug.
 
 Just to check, when you say clean, you mean like this, right?
    # fsck -f /dev/rwd0f
    ** /dev/rwd0f
    ** File system is already clean
    ** Last mounted on /scratch
    ** Phase 1 - Check Blocks and Sizes
    ** Phase 2 - Check Pathnames
    ** Phase 3 - Check Connectivity
    ** Phase 4 - Check Reference Counts
    ** Phase 5 - Check Cyl groups
    1 files, 1 used, 253998 free (14 frags, 31748 blocks, 0.0% fragmentation)
    # 
 
 That is, it fscks cleanly, rather than merely this:
    # fsck /dev/rwd0f
    ** /dev/rwd0f
    ** File system is clean; not checking
    # 
 
 because the clean bit in the superblock only means the fs is correct
 if there are no bugs in either the kernel or fsck. Which would be a
 nice thing to be able to claim, but isn't true.
 
 (And I believe if you mount a volume without fscking it and then
 unmount it, it will subsequently purport to be clean, even though it
 may in fact be nothing of the sort.)
 
 -- 
 David A. Holland
 dholland%netbsd.org@localhost