On Tue, 10 Jul 2012 18:51:22 +0200 Sebastian Hegler
<sebastian.hegler@tu-dresden.de> wrote:

> Hi!
> 

Hi,
 thanks for all the extra details.

I should have asked which kernel you were running.  I'm guessing that it is
earlier than 2.6.25, and so is missing upstream commit
   25156198235325805cd7295ed694509fd6e3a29e

that fixes a bug which causes reshape not to restart if array was assembled
auto-read-only.

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=25156198235325805cd7295ed694509fd6e3a29e

The mdadm bug is because we never tested the code with anything but IMSM
arrays because those are the only ones that need to use it.
Adding a test for 'mdstat' being NULL and not trying to call
verify_reshape_position in that case is the simplest fixed I expect, though I
haven't tested yet. Possibly something more thorough is needed.


NeilBrown