Ceph

original description¶

In ObjectCacher::bh_read_finish, we have a nonsense snippet

      } else {
        bh->bl.substr_of(bl,
                         oldpos-bh->start(),
                         bh->length());
        mark_clean(bh);
      }

Here we're trying to map the offsets of an incoming OSD op reply's bufferlist with our BufferHeads. But oldpos==bh->start at all times. The correct offset calculation is "bh->start()-start" ("start" being a function parameter corresponding to bl's position within the object).

The patch is obviously simple enough, but I want tests verifying it as well.

https://github.com/ceph/ceph/pull/10074

Sepia's idle right now so I'll run this through on its own once gitbuilders are done.

Forgot to update this. These are good results: http://pulpito.ceph.com/?branch=jewel-16002

Nathan, I'm assigning to you so this is in somebody's hands and I think I've seen you poking at it lately. ;)