readx and CAP_LARGE_READX

[tridge at samba.org]

James,

 > With the attached patch, I/O sizes of up to 127K work correctly  
 > against Samba3. This patch is not the best or most correct way to  
 > implement this in Samba4, but it works for this case :)

Unfortunately the patch would break any chained replies. It assumes
that the NBT packet size == header + body, but when you have chained
replies, there is more than one body in the packet, so you'd end up
passing the vwv buffer and the body of the 2nd reply in the chain as
data to the readx code. Not good :-)

I'll probably do something much more specific, only triggering this
code if its a readx reply with the chaining function set to 0xFF.

I'm guessing this is also why w2k3 doesn't do these sorts of requests
- with chained requests and/or signing it gets _very_ messy.

Cheers, Tridge