Bug 231050

Summary: NFS via IPv6 between 11.2-REL amd64 fails for larger directories
Product: Base System Reporter: Kurt Jaeger <pi>
Component: kernAssignee: freebsd-bugs (Nobody) <bugs>
Status: Closed DUPLICATE    
Severity: Affects Only Me CC: kp, pi
Priority: ---    
Version: 11.2-RELEASE   
Hardware: Any   
OS: Any   

Description Kurt Jaeger freebsd_committer freebsd_triage 2018-08-31 07:42:27 UTC
NFS via IPv6 between 11.2-REL amd64
boxes failed for directories with more than 45 files or directories.
Small directories worked. It seems to be an issue with
ipv6 fragmentation (?), as can be seen by tcpdump:
     
17:54:16.855978 IP6 nfs-serv > nfs-client frag (0|1448) 2049 > 709: NFS
reply xid 1536109002 reply ok 1440 readdir
17:54:16.855979 IP6 nfs-serv > nfs-client frag (1448|36)
     
As soon as the NFS request is sent with fragments, it stalls.

Using TCP or IPv4 for the nfs mount works, UDP fails.
Comment 1 Kristof Provost freebsd_committer freebsd_triage 2018-08-31 07:55:28 UTC
This is very likely caused by #231045. (Assuming you've installed the latest security patches.)
There's a problem with IPv6 fragment reassembly. The fix should go in HEAD soon, and I assume there'll be an EN about it too.
Comment 2 Kurt Jaeger freebsd_committer freebsd_triage 2018-08-31 07:58:59 UTC

*** This bug has been marked as a duplicate of bug 231045 ***