From f722a75fe21963d64217375f1f7bbb0eb14befb4 Mon Sep 17 00:00:00 2001 From: Simon Wilkinson Date: Wed, 12 Oct 2011 09:47:14 -0400 Subject: [PATCH] rx: Don't clear the receive queue when out of packets We can end up discarding a receive queue that's been soft acked, effectively taking back soft acks we sent. Whilst the RX documentation says that a client can drop soft acked packets at will, our RX implementation assumes that if the final packet in a call has been soft acked, we won't clear the queue. If a client clears the queue in this situation, the call will hang. What *should* happen is that we should take necessary locks, confirm that we have not soft-acked all of the packets in a flow, and then discard, or, if we're just going to discard, error the call. Change-Id: Ic8e358b8648c1a6f0154009093468531a9e3cf74 Reviewed-on: http://gerrit.openafs.org/5603 Reviewed-by: Derrick Brashear Tested-by: Derrick Brashear --- src/rx/rx.c | 5 +++-- src/rx/rx_globals.h | 1 - 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/src/rx/rx.c b/src/rx/rx.c index b6a13168fa..bb49d60d0c 100644 --- a/src/rx/rx.c +++ b/src/rx/rx.c @@ -3803,8 +3803,9 @@ rxi_ReceiveDataPacket(struct rx_call *call, call->rprev = np->header.serial; rxi_calltrace(RX_TRACE_DROP, call); dpf(("packet %"AFS_PTR_FMT" dropped on receipt - quota problems\n", np)); - if (rxi_doreclaim) - rxi_ClearReceiveQueue(call); + /* We used to clear the receive queue here, in an attempt to free + * packets. However this is unsafe if the queue has received a + * soft ACK for the final packet */ clock_GetTime(&now); when = now; clock_Add(&when, &rx_softAckDelay); diff --git a/src/rx/rx_globals.h b/src/rx/rx_globals.h index 3e17c7cb8c..1e51890d00 100644 --- a/src/rx/rx_globals.h +++ b/src/rx/rx_globals.h @@ -481,7 +481,6 @@ EXT osi_socket rx_minSocketNumber GLOBALSINIT(0x7fffffff); #define RX_MAX_QUOTA 15 /* part of min packet computation */ EXT int rx_packetQuota[RX_N_PACKET_CLASSES] GLOBALSINIT(RX_PACKET_QUOTAS); EXT int meltdown_1pkt GLOBALSINIT(1); /* prefer to schedule single-packet calls */ -EXT int rxi_doreclaim GLOBALSINIT(1); /* if discard one packet, discard all */ EXT int rxi_md2cnt GLOBALSINIT(0); /* counter of skipped calls */ EXT int rxi_2dchoice GLOBALSINIT(1); /* keep track of another call to schedule */