NLM: don't let lockd exit on unexpected svc_recv errors (try #2) (f97c650d) · Commits · 戴 / test

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@redhat.com> Signed-off-by:

J. Bruce Fields <bfields@citi.umich.edu>

fs/lockd/svc.c

+12 −6

Original line number	Diff line number	Diff line
		@@ -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);
		continue;
		}
		preverr = err;

		dprintk("lockd: request from %s\n",
		svc_print_addr(rqstp, buf, sizeof(buf)));

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