Re: Bugreport ddf rebuild problems

[Martin Wilck <mwilck@arcor.de>]

Hi Albert, Neil,

I just submitted a new patch series; patch 3/5 integrates your 2nd case
as a new unit test and 4/5 should fix it.

However @Neil: I am not yet entirely happy with this solution. AFAICS
there is a possible race condition here, if a disk fails and mdadm -CR
is called to create a new array before the metadata reflecting the
failure is written to disk. If a disk failure happens in one array,
mdmon will call reconcile_failed() to propagate the failure to other
already known arrays in the same container, by writing "faulty" to the
sysfs state attribute. It can't do that for a new container though.

I thought that process_update() may need to check the kernel state of
array members against meta data state when a new VD configuration record
is received, but that's impossible because we can't call open() on the
respective sysfs files. It could be done in prepare_update(), but that
would require major changes, I wanted to ask you first.

Another option would be changing manage_new(). But we don't seem to have
a suitable metadata handler method to pass the meta data state to the
manager....

Ideas?

Regards
Martin