NLM: Ensure that nlmclnt_cancel_callback() doesn't loop forever (aaaa9942) · Commits · 戴 / test

If the server returns NLM_LCK_DENIED_NOLOCKS, we currently retry the entire NLM_CANCEL request. This may end up looping forever unless the server changes its mind (why would it do that, though?). Ensure that we limit the number of retries (to 3). See bug# 5957 in bugzilla.kernel.org. Signed-off-by:

Trond Myklebust <Trond.Myklebust@netapp.com>

fs/lockd/clntproc.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@
		#define NLMDBG_FACILITY NLMDBG_CLIENT
		#define NLMCLNT_GRACE_WAIT (5*HZ)
		#define NLMCLNT_POLL_TIMEOUT (30*HZ)
		#define NLMCLNT_MAX_RETRIES 3

		static int nlmclnt_test(struct nlm_rqst , struct file_lock );
		static int nlmclnt_lock(struct nlm_rqst , struct file_lock );
		@@ -802,6 +803,9 @@ die:
		return;

		retry_cancel:
		/* Don't ever retry more than 3 times */
		if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
		goto die;
		nlm_rebind_host(req->a_host);
		rpc_restart_call(task);
		rpc_delay(task, 30 * HZ);

include/linux/lockd/lockd.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -84,6 +84,7 @@ struct nlm_rqst {
		struct nlm_args a_args; /* arguments */
		struct nlm_res a_res; /* result */
		struct nlm_wait * a_block;
		unsigned int a_retries; /* Retry count */
		char a_owner[NLMCLNT_OHSIZE];
		};

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