Re: kern/42455: tstile hang with nfs

["Christoph Egger" <Christoph_Egger%gmx.de@localhost>]

The following reply was made to PR kern/42455; it has been noted by GNATS.

From: "Christoph Egger" <Christoph_Egger%gmx.de@localhost>
To: gnats-bugs%NetBSD.org@localhost, netbsd-bugs%netbsd.org@localhost, 
gnats-admin%netbsd.org@localhost,
 kern-bug-people%netbsd.org@localhost
Cc: 
Subject: Re: kern/42455: tstile hang with nfs
Date: Tue, 19 Oct 2010 14:13:12 +0200

 With the patch below, I always see that ctx.nwc_mbufcount is
 always 1.
 
 Christoph
 
 
 Index: nfs_vnops.c
 ===================================================================
 RCS file: /cvsroot/src/sys/nfs/nfs_vnops.c,v
 retrieving revision 1.284
 diff -u -p -r1.284 nfs_vnops.c
 --- nfs_vnops.c 24 Jun 2010 13:03:17 -0000      1.284
 +++ nfs_vnops.c 19 Oct 2010 12:11:11 -0000
 @@ -1468,7 +1468,16 @@ nfsmout:
                 mutex_enter(&ctx.nwc_lock);
                 ctx.nwc_mbufcount--;
                 while (ctx.nwc_mbufcount > 0) {
 -                       cv_wait(&ctx.nwc_cv, &ctx.nwc_lock);
 +                       error = cv_timedwait(&ctx.nwc_cv, &ctx.nwc_lock,
 +                           mstohz(1000));
 +                       if (error) {
 +                               printf("nfsmblk timeout, mbufcount %i\n",
 +                                       ctx.nwc_mbufcount);
 +                               mutex_exit(&ctx.nwc_lock);
 +                               Debugger();
 +                               mutex_enter(&ctx.nwc_lock);
 +                               continue;
 +                       }
                 }
                 mutex_exit(&ctx.nwc_lock);
         }