Re: [PATCH 2.6.0-test3] avoid raid1 resync abort

On Wednesday August 20, Paul.Clements@SteelEye.com wrote:

Neil,

I don't know if you've noticed this one yet, but it looks like we need
to set the master_bio->bi_bdev field at the beginning of every resync
request. We use this value later on in sync_request_write() to determine
whether a write should take place on a particular device. Without the
field being properly set, we will end up aborting the resync process.
This happens because the master_bios are pulled from a pool, so we
eventually end up getting a master_bio that already has our destination
disk set in its bi_bdev field. This causes sync_request_write() to fail
since it thinks there is nowhere to write the data to. 

Thanks.  Your analysis looks right.
However it raises a question:  why are we cloning a separate bio for
reading instead of jus using the "master bio" ???

I'll have a deeper look at raid1 in a few days and see what I can
find.

NeilBrown