The db/ops directory could be improved in two ways:

• This code is owned by the query team and is related to query processing, so I think it makes to move it into the db/query directory.
• The name "ops" is somewhat vague. It's specifically about processing write operations. Therefore, I think "write_ops" is a clearer name for the directory. This also has nice symmetry with an existing directory for write op processing on mongos: https://github.com/10gen/mongo/tree/master/src/mongo/s/write_ops.

My proposal is to move this code from db/ops to a new directory called db/query/write_ops.