Re: [libvirt] [RFC][PATCH] Revision for message payload encoding error when adding a large mount of virtio disks

On 19.04.2012 14:45, Richard W.M. Jones wrote: > On Thu, Apr 19, 2012 at 02:25:16PM +0800, Chen Hanxiao wrote: >> * This is an arbitrary limit designed to stop the decoder from trying >> * to allocate unbounded amounts of memory when fed with a bad message. >> */ >> -const REMOTE_STRING_MAX = 65536; >> +const REMOTE_STRING_MAX = 80000; > > Can this limit be changed? I thought it would break existing clients > or servers. > > Rich. > Yes & no. There are 4 possibilities: - old both server & client: long string get dropped at server side and "unable to encode string/payload" error is thrown. - old server & new client: if server wants to send long string it's the previous case; client will successfully retransmit message to the daemon where it gets later dropped because of limit violation. - new server & old client: see previous case - new server & new client: nothing gets broken, everything works. The only problem is with these gimme-list-of-* APIs. Because here you'll get only partial result (first N entries - based on RPC limit). Thus, changing this limit is okay.