nfs4_getfacl "Failed getxattr operation" when too many ACL entries exist

[Brian De Wolf <bldewolf@csupomona.edu>]

Recently we've been prototyping serving Solaris ZFS exports via NFSv4 to some 
Linux hosts.  These will some day be exposed to general users, so I've been 
testing things to see if I can break them.  Anyway, it seems that nfs4_getfacl 
is only able to read ACLs with up to 208 entries.  nfs4_setfacl is able to 
insert a 209th entry, but any attempts to view or edit the ACLs after that fail 
with:

Failed getxattr operation
: Input/output error

There are two ways to make the ACLs readable again:
1) Have someone log in to the Solaris box and remove some of the entries
2) Reset the ACLs using nfs4_setfacl -s `some spec`

Has anyone run into this issue before?  Is it fixable?  I didn't reach the same 
problem locally on the Solaris box, nor on another Solaris box with the same NFS 
mount, so it looks like it's a problem specific to Linux.  Here's the versions 
of relevant packages on the test box running Gentoo (did I miss any?):
Kernel: 2.6.23-gentoo-r8
nfs-utils-1.1.0-r1
attr-2.4.39
nfs4-acl-tools-0.3.2