tree 921f08b555d2b71e7356034aae65bed4ed37e2df
parent 11f770027b5c0de16544f3ec82b5c6f9f8d5a644
author Yehuda Sadeh <yehuda@hq.newdream.net> 1305319976 -0700
committer Sage Weil <sage@newdream.net> 1305319977 -0700

rbd: fix split bio handling

The rbd driver currently splits bios when they span an object boundary.
However, the blk_end_request expects the completions to roll up the results
in block device order, and the split rbd/ceph ops can complete in any
order.  This patch adds a struct rbd_req_coll to track completion of split
requests and ensures that the results are passed back up to the block layer
in order.

This fixes errors where the file system gets completion of a read operation
that spans an object boundary before the data has actually arrived.  The
bug is easily reproduced with iozone with a working set larger than
available RAM.

Reported-by: Fyodor Ustinov <ufm@ufm.su>
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>