Frank Filz has uploaded this change for review. ( https://review.gerrithub.io/c/ffilz/nfs-ganesha/+/528935 ) Change subject: DRC: Better handle duplicate requests while a request is in progress ...................................................................... DRC: Better handle duplicate requests while a request is in progress The old code would drop any duplicate request while the original request was still in progress, assuming that the response would be sent. Unfortunately, if a TCP connection is broken while the request is in progress, sending the response fails. The client never retries and gets stuck. Now when this occurs, we queue up the request and suspend it (utlizing the async infrastructure). When the original request processing completes and calls nfs_dupreq_finish() we track if there was an error sending the response. If so, we don't mark the DRC entry as complete and instead resume the first retry to attempt to send the response. That resumed retry will call nfs_dupreq_finish() after it tries to send the response, so if there is a queue of retries, there are more opportunities to re-send a failed response. The same retry logic is followed when nfs_dupreq_delete() is called if there are again queued duplicate requests, however, those retries instead are re-submitted for a new attempt to process. This logic occurs when there is an NFS_DROP result from a retryable error or an auth error. Once the request is succesfully completed, any additional queued requests are dropped. We limit the queue to 3 duplicates. That should be more than enough to get through an issue like this unless the server has severely stalled out on the original request. Change-Id: Ia1d207aefdddb6845987856c9f1073b2f7167e94 Signed-off-by: Frank S. Filz <ffilzlnx(a)mindspring.com&gt; --- M src/MainNFSD/nfs_rpc_dispatcher_thread.c M src/MainNFSD/nfs_worker_thread.c M src/RPCAL/nfs_dupreq.c M src/include/nfs_dupreq.h M src/include/nfs_proto_data.h M src/include/nfs_proto_functions.h 6 files changed, 372 insertions(+), 159 deletions(-) git pull ssh://review.gerrithub.io:29418/ffilz/nfs-ganesha refs/changes/35/528935/1 -- To view, visit https://review.gerrithub.io/c/ffilz/nfs-ganesha/+/528935 To unsubscribe, or for help writing mail filters, visit https://review.gerrithub.io/settings Gerrit-Project: ffilz/nfs-ganesha Gerrit-Branch: next Gerrit-Change-Id: Ia1d207aefdddb6845987856c9f1073b2f7167e94 Gerrit-Change-Number: 528935 Gerrit-PatchSet: 1 Gerrit-Owner: Frank Filz <ffilzlnx(a)mindspring.com&gt; Gerrit-MessageType: newchange