Re: kern/57691: NFS client regression with macOS 14 server

[Jason Thorpe <thorpej%me.com@localhost>]

The following reply was made to PR kern/57691; it has been noted by GNATS.

From: Jason Thorpe <thorpej%me.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: kern-bug-people%netbsd.org@localhost,
 gnats-admin%netbsd.org@localhost,
 netbsd-bugs%netbsd.org@localhost,
 NetBSD Kernel Technical Discussion List <tech-kern%NetBSD.org@localhost>
Subject: Re: kern/57691: NFS client regression with macOS 14 server
Date: Fri, 8 Dec 2023 10:55:54 -0800

 > On Nov 10, 2023, at 11:10=E2=80=AFAM, schmonz%netbsd.org@localhost =
 <schmonz%NetBSD.org@localhost> wrote:
 >=20
 > tcpdump of "ls" after the problem has manifested:
 > https://netbsd.schmonz.com/tmp/nfs/ls-after-the-problem-tcpdump.txt
 
 The tcpdump shows:
 
 16:16:35.683996 IP 10.0.2.2.shilp > 10.0.2.15.exp2: Flags [P.], seq =
 1573:1693, ack 1508, win 65535, length 120: NFS reply xid 834502658 =
 reply ok 116 readdir ERROR: READDIR/READDIRPLUS cookie is stale
 
 Looking at the code that issues READDIRPLUS in the kernel in =
 nfs_readdirplusrpc():
 
                 if (nmp->nm_iflag & NFSMNT_SWAPCOOKIE) {
                         txdr_swapcookie3(uiop->uio_offset, tl);
                 } else {
                         txdr_cookie3(uiop->uio_offset, tl);
                 }
                 tl +=3D 2;
                 *tl++ =3D dnp->n_cookieverf.nfsuquad[0];
                 *tl++ =3D dnp->n_cookieverf.nfsuquad[1];
                 *tl++ =3D txdr_unsigned(nmp->nm_readdirsize);
 
 I think the cookie verifier is wrong.  See: =
 https://www.rfc-editor.org/rfc/rfc1813#page-81
 
       cookieverf
 This should be set to 0 on the first request to read a
 directory. On subsequent requests, it should be a
 cookieverf as returned by the server. The cookieverf
 must match that returned by the READDIRPLUS call in
 which the cookie was acquired.
 
 Probably what=E2=80=99s going on is that the server is verifying the =
 directory cookie more strictly than before.  Those two lines that pack =
 the cookieverf should be inserting 0s if uno_offset is 0.
 
 -- thorpej