tree c54b572ad4c4c9b48f887a9ecc28ec7b6166d552
parent b5e98d65d34a1c11a2135ea8a9b2619dbc7216c8
author Dan Williams <dan.j.williams@intel.com> 1167771151 -0700
committer Dan Williams <dan.j.williams@intel.com> 1184339177 -0700

md: handle_stripe5 - add request/completion logic for async expand ops

When a stripe is being expanded bulk copying takes place to move the data
from the old stripe to the new.  Since raid5_run_ops only operates on one
stripe at a time these bulk copies are handled in-line under the stripe
lock.  In the dma offload case we poll for the completion of the operation.

After the data has been copied into the new stripe the parity needs to be
recalculated across the new disks.  We reuse the existing postxor
functionality to carry out this calculation.  By setting STRIPE_OP_POSTXOR
without setting STRIPE_OP_BIODRAIN the completion path in handle stripe
can differentiate expand operations from normal write operations.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-By: NeilBrown <neilb@suse.de>