sunrpc: Don't engage exponential backoff when connection attempt is rejected.
xs_connect() contains an exponential backoff mechanism so the repeated connection attempts are delayed by longer and longer amounts. This is appropriate when the connection failed due to a timeout, but it not appropriate when a definitive "no" answer is received. In such cases, call_connect_status() imposes a minimum 3-second back-off, so not having the exponetial back-off will never result in immediate retries. The current situation is a problem when the NFS server tries to register with rpcbind but rpcbind isn't running. All connection attempts are made on the same "xprt" and as the connection is never "closed", the exponential back delays successive attempts to register, or de-register, different protocols. This results in a multi-minute delay with no benefit. So, when call_connect_status() receives a definitive "no", use xprt_conditional_disconnect() to cancel the previous connection attempt. This will set XPRT_CLOSE_WAIT so that xprt->ops->close() calls xs_close() which resets the reestablish_timeout. To ensure xprt_conditional_disconnect() does the right thing, we ensure that rq_connect_cookie is set before a connection attempt, and allow xprt_conditional_disconnect() to complete even when the transport is not fully connected. Signed-off-by:NeilBrown <neilb@suse.com> Signed-off-by:
Trond Myklebust <trond.myklebust@primarydata.com>
parent
b85f5620
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