Changes to kern.geom.debugflags?

[Chris Ross]

On Jan 4, 2013, at 18:46 , Marius Strobl <marius at alchemy.franken.de> wrote:
>>  So, now that we're past the holiday madness, and I haven't heard anything back
>> on this is there some other group or list I should ask the questions of ZFS internals
>> to figure out why the sparc64 MD boot loader code is seeing a dn_datablkszsec
>> of 0, and what it should be set to?
>> 
>>  Thanks.  I'm happy to compose another message to include people who might
>> be able to help.  I'm out of my "comfort zone" in ZFS.
> 
> The most straightforward way is to identify the commit that broke
> it via a binary search and email the corresponding commit.

  Okay.  I've completed this search.  SVN rev 242228 works, boots up, the first call
to dnode_read() (in sys/boot/zfs/zfsimpl.c) (well, "first" call after the console is initialized)
shows (due to a printf I added) :

dnode_read(): offset 512, bsize 16384, dn_datablkszsec 32

  I notice in all of the many following calls that bsize is always 512 or 16384, and
dn_datablkszsec is sometimes as small as 1, or as large as 68, but always non-zero.

  SVN revision 242230 fails in the same way the head of stable/9 does.  The first output
I see from my printf in dnode_read() is (and the following trap):

dnode_read(): offset 512, bsize 0, dn_datablkszsec 0
ERROR: Last Trap: Division by Zero

  I didn't test 242229,. but could if needed, because both 242229 and 242230 were
ZFS changes in the boot code, and by the same person.

------------------------------------------------------------------------
r242229 | avg | 2012-10-28 11:45:18 -0400 (Sun, 28 Oct 2012) | 3 lines

MFC r241283: zfs boot: add code for listing child datasets of a given
dataset

------------------------------------------------------------------------
------------------------------------------------------------------------
r242230 | avg | 2012-10-28 11:47:56 -0400 (Sun, 28 Oct 2012) | 2 lines

MFC r241289: boot/zfs: call zfs_spa_init for all found pools

------------------------------------------------------------------------

  Should this go to Andriy, or is someone else more familiar with spar64
issues?  These seem to come from a range of ZFS changes
by Andriy (r241282 - r241294) on October 6.  Something got messed up for
the sparc64 code, though.

  Thanks.

                                    - Chris