[dm-devel] [PATCH][RFC] dm: Do not open log and cow device read-write for read-only mappings

[Tejun Heo]

On Tue, Feb 15, 2011 at 05:58:45PM +0100, Milan Broz wrote:
> # blockdev --setrw /dev/sd[bcde]
> # mdadm -A /dev/md0 /dev/sd[bcde]
> mdadm: /dev/md0 has been started with 4 drives.
> # mdadm --stop /dev/md0
> mdadm: stopped /dev/md0
> # blockdev --setro /dev/sd[bcde]
> # mdadm -A /dev/md0 /dev/sd[bcde]
> mdadm: cannot re-read metadata from /dev/sdb - aborting
> 
> Works on 2.6.36.

Isn't failing to assemble rw array from ro devices the expected
behavior?  I think I'd want that to fail.  Neil, what do you think?

-- 
tejun