kern/159222: [boot0] unusual behavior writing boot0 from single user mode

[Andriy Gapon]

The following reply was made to PR kern/159222; it has been noted by GNATS.

From: Andriy Gapon <avg at FreeBSD.org>
To: Tim Newsham <tim.newsham at gmail.com>
Cc: bug-followup at FreeBSD.org
Subject: Re: kern/159222: [boot0] unusual behavior writing boot0 from single
 user mode
Date: Sat, 30 Jul 2011 11:03:04 +0300

 on 28/07/2011 19:59 Tim Newsham said the following:
 > On Thu, Jul 28, 2011 at 5:27 AM, Andriy Gapon <avg at freebsd.org> wrote:
 >> I've noticed that you report a problem with performing some disk-related
 >> operations, but you haven't provided any information about your disk partitioning
 >> and filesystem layout.
 >> Also you emphasized that the problem occurs in the single user mode, but it is not
 >> immediately clear if you tested the same operations in the multi-user mode.
 > 
 > I believe I got a permission denied error when trying in multi
 > user mode.  I assumed it was due to secure level.  I just tried it
 > again now and it asked me twice for confirmation and when I
 > did reported:
 >   fdisk: Class not found
 >   fdisk: Failed to write sector zero
 > 
 > at this point none of the issues I reported in the bug occur.
 
 Can you also try to perform a supposedly equivalent operation using gpart?
 /sbin/gpart bootcode -b /boot/boot0 da0
 Both in multi-user and single-user modes?
 
 > As for disks, I have tried on two separate systems.  One system was
 > created just for this test in vmware and used the .iso installer
 > and accepted the default partitioning and slicing offered by the installer.
 > I assume there's nothing special about it:
 > 
 > ******* Working on device /dev/da0 *******
 > parameters extracted from in-core disklabel are:
 > cylinders=1044 heads=255 sectors/track=63 (16065 blks/cyl)
 > 
 > Figures below won't work with BIOS for partitions not in cyl 1
 > parameters to be used for BIOS calculations are:
 > cylinders=1044 heads=255 sectors/track=63 (16065 blks/cyl)
 > 
 > Media sector size is 512
 > Warning: BIOS sector numbering starts with sector 1
 > Information from DOS bootblock is:
 > The data for partition 1 is:
 > sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
 >     start 63, size 16771797 (8189 Meg), flag 80 (active)
 >         beg: cyl 0/ head 1/ sector 1;
 >         end: cyl 1023/ head 254/ sector 63
 > The data for partition 2 is:
 > <UNUSED>
 > The data for partition 3 is:
 > <UNUSED>
 > The data for partition 4 is:
 > <UNUSED>
 
 Can you pls also provide gpart show and gpart list outputs?
 
 -- 
 Andriy Gapon