Detect and report overlapping Read chunks

[chucklever]

Is it possible for a requester to form an RPC/RDMA message where a byte-range appears in more than one Read chunk? For example, suppose there are two Read chunks in a message:

• Inline: 32 bytes
• Chunk A: 8 bytes at position 16
• Chunk B: 8 bytes at position 24

Chunk B starts in the middle of chunk A. How is the responder going to re-assemble this message? If it can't, how does it report that the message is unparsable? ERR_CHUNK / RDMA2_ERR_BAD_XDR is probably the right choice.

The question is whether a more specific error response is needed from the responder. Probably no: this is not expected to be a frequent error condition, and it is the sign of a broken requester implementation, rather than an exigent circumstance.

However, it might be proper and helpful if the document guided responder implementors to check for this particular case.

[chucklever]

How about the case where a Read segment is at a position that is beyond the end of the message?