On Wed, 2019-08-28 at 17:06 -0400, bfields@xxxxxxxxxxxx wrote: > On Wed, Aug 28, 2019 at 08:25:16PM +0000, Trond Myklebust wrote: > > Umm... Don't forget that NFSv4 ACL aces are typically much larger > > than > > POSIX ACL aces because the user/group names are encoded as strings, > > not > > binary uids and gids. > > > > IOW: The size of the RPC message is likely to be a lot larger than > > the > > resulting POSIX ACL... > > Actually this limit is post-idmapping, but, yes, before NFSv4->Posix > mapping (complicated in itself), which is why I talked about having > to > estimate. > > More interested to hear what you think about whether we need a limit > at > all. Do we have any ideas how big is too big a number to pass to > kmalloc? Or is it OK to just let anything through and let kmalloc > fail? > A NFSv4.x client is always required to respect the max request size as negotiated during CREATE_SESSION, so there is an upper limit right there. On Linux, the client will never try to negotiate a limit greater than 1MB. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@xxxxxxxxxxxxxxx
