> On Mar 23, 2021, at 5:56 PM, Pradeep <pradeepthomas@xxxxxxxxx> wrote: > > Hello, > > While testing NFSv4 referrals, I noticed that if the server name in FS > locations does not have IPv4 mapping (server name has AAAA record for > IPv6; but no A record in DNS), the referral mount fails. IIRC, that is a known bug, but it has been rarely hit up to this point (only case I'm aware of is during testing, which is how I know about this issue). The DNS upcall needs to be fixed to handle this case properly. As Bruce likes to say, patches welcome! > With debug enabled, I get something like this: > > nfs_follow_referral: referral at /nfs_export_1 > nfs4_path: path server-1.domain.com:/nfs_export_1 from nfs_path > nfs4_path: path component /nfs_export_1 > nfs4_validate_fspath: comparing path /nfs_export_1 with fsroot /nfs_export_1 > ==> dns_query((null),server-2.domain.com,19,(null)) > call request_key(,server-2.domain.com,) > <== dns_query() = -126 > nfs_follow_referral: done > nfs_do_refmount: done > RPC: shutting down nfs client for server-1.domain.com > RPC: rpc_release_client(ffff97fdf170c600) > RPC: destroying nfs client for server-1.domain.com > <-- nfs_d_automount(): error -2 > > It looks like NFS client does an upcall to "/sbin/key.dns_resolver". > "/sbin/key.dns_resolver" works if callout info is set to 'ipv6'. > Otherwise it fails too. > > Does this mean setups with only IPv6 records (AAAA records in DNS), > NFSv4 referrals won't work if server returns FQDN in referral? If > anyone has tried this and made it work, please let me know. > > Thanks, > Pradeep -- Chuck Lever
