Messages in this thread | | | From | Sowmini Varadhan <> | Subject | [PATCH 0/2] net/rds: RDS-TCP robustness fixes | Date | Sat, 2 May 2015 07:55:07 -0400 |
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This patch-set contains bug fixes for state-recovery at the RDS layer when the underlying transport is TCP and the TCP state at one of the endpoints is reset, e.g., due to a "modprobe -r rds_tcp" or a reboot.
When that situation happens, the existing code does not correctly clean up RDS socket state for stale connections, resulting in some unstable, timing-dependant behavior on the wire, including an infinite exchange of 3WHs back-and-forth, and a resulting potential to never converge RDS state.
Test cases used to verify the changes in this set are:
1. Start rds client/server applications on two participating nodes, node1 and node1. After at least one packet has been sent (to establish the TCP connection), restart the rds_tcp module on the client, and now resend packets. Tcpdump should show server sending a FIN for the "old" client port, and clean connection establishment/exchange for the new client port.
2. At the end of step 1, restart rds srever on node2, and start client on node1, make sure using tcpdump, 'netstat -an|grep 16385' that packets flow correctly. Sowmini Varadhan (2): RDS-TCP: Always create a new rds_sock for an incoming connection. RDS-TCP: only initiate reconnect attempt on outgoing TCP socket.
net/rds/connection.c | 17 ++++++++++++++- net/rds/tcp.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++- net/rds/tcp.h | 5 +++- net/rds/tcp_connect.c | 2 +- net/rds/tcp_listen.c | 13 +++++++++++- 5 files changed, 82 insertions(+), 6 deletions(-)
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