Re: link() not increasing link count on NFS server

Robert Watson <rwatson_at_FreeBSD.org> writes:
> Indeed, and inspection of nfs_vnops.c:nfs_link(): finds:
>
> 1772         /*
> 1773          * Kludge: Map EEXIST => 0 assuming that it is a reply to a retry.
> 1774          */
> 1775         if (error == EEXIST)
> 1776                 error = 0;
> 1777         return (error);
>
> Neither Linux nor Solaris appears to have this logic in the client.  I
> assume this is, as suggested, to work around UDP retransmissions where
> the reply is lost rather than the request.  It appears to exist in
> revision 1.1 of nfs_vnops.c, so came in with 4.4BSD in the initial
> import, but doesn't appear in NetBSD so I'm guessing they've removed
> it.

Wrong, it still exists in NetBSD, but they've separated part of
nfs_link() (including that bit) out into nfs_linkrpc().  They also seem
to have added logic to detect a retransmit:

        /*
         * Kludge: Map EEXIST => 0 assuming that it is a reply to a retry.
         */
        if (rexmit && error == EEXIST)
                error = 0;

revision 1.197
date: 2004/05/10 10:40:42;  author: yamt;  state: Exp;  lines: +32 -25
don't do kludge for a reply to a retransmitted request
unless we actually retransmitted the request.

DES
-- 
Dag-Erling Smørgrav - des_at_des.no