On Tue, 08 Apr 2008 16:15:58 -0400
Trond Myklebust <trond.myklebust@xxxxxxxxxx> wrote:
>
> On Tue, 2008-04-08 at 15:40 -0400, Jeff Layton wrote:
> > When svc_recv returns an unexpected error, lockd will print a warning
> > and exit. This problematic for several reasons. In particular, it will
> > cause the reference counts for the thread to be wrong, and can lead to a
> > potential BUG() call.
> >
> > Rather than exiting on error from svc_recv, have the thread do a 1s
> > sleep and then retry the loop. This is unlikely to cause any harm, and
> > if the error turns out to be something temporary then it may be able to
> > recover.
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > ---
> > fs/lockd/svc.c | 18 ++++++++++++------
> > 1 files changed, 12 insertions(+), 6 deletions(-)
> >
> > diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> > index 66b5c98..cf977bb 100644
> > --- a/fs/lockd/svc.c
> > +++ b/fs/lockd/svc.c
> > @@ -112,7 +112,7 @@ static inline void clear_grace_period(void)
> > static int
> > lockd(void *vrqstp)
> > {
> > - int err = 0;
> > + int err = 0, preverr = 0;
> > struct svc_rqst *rqstp = vrqstp;
> > unsigned long grace_period_expire;
> >
> > @@ -172,14 +172,20 @@ lockd(void *vrqstp)
> > * recvfrom routine.
> > */
> > err = svc_recv(rqstp, timeout);
> > - if (err == -EAGAIN || err == -EINTR)
> > + if (err == -EAGAIN || err == -EINTR) {
> > + preverr = err;
> > continue;
> > + }
> > if (err < 0) {
> > - printk(KERN_WARNING
> > - "lockd: terminating on error %d\n",
> > - -err);
> > - break;
> > + if (err != preverr) {
> > + printk(KERN_WARNING "%s: unexpected error "
> > + "from svc_recv (%d)\n", __func__, err);
> > + preverr = err;
> > + }
> > + schedule_timeout_interruptible(HZ);
>
> Why not use an uninterruptible sleep?
>
> Trond
>
lockd can receive a SIGKILL to tell it to drop all locks, so I figured
it was reasonable to allow the sleep to be interrupted if that happens.
It probably doesn't matter much either way though...
--
Jeff Layton <jlayton@xxxxxxxxxx>
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