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[Richard Laager <rlaager@xxxxxxxxxx>]

** Attachment added: "dovecot-test.upstream-kernel.pcap"
   https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1542826/+attachment/4571304/+files/dovecot-test.upstream-kernel.pcap

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https://bugs.launchpad.net/bugs/1542826

Title:
  NFS Client Ignores TCP Resets

Status in linux package in Ubuntu:
  Triaged

Bug description:
  Steps to reproduce:
  1) Mount NFS share from HA cluster with TCP.
  2) Failover the HA cluster. (The NFS server's IP address moves from one
  machine to the other.)
  3) Access the mounted NFS share from the client (an `ls` is sufficient).

  Expected results:
  Accessing the NFS mount works fine immediately.

  Actual results:
  Accessing the NFS mount hangs for 5 minutes. Then the TCP connection times out, a new connection is established, and it works fine again.

  After the IP moves, the new server responds to the client with TCP RST
  packets, just as I would expect. I would expect the client to tear
  down its TCP connection immediately and re-establish a new one. But it
  doesn't. Am I confused, or is this a bug?

  For the duration of this test, all iptables firewalling was disabled
  on the client machine. I have a packet capture of a minimized test
  (just a simple ls).

  Note that this is a "single failover" scenario. It is NOT a case of
  failing over and then failing back before the TCP connection times out
  on the first NFS server.

  We've been using UDP instead of TCP as a work-around.

  The system is running Ubuntu 14.04 with Linux 3.13.0-76-generic.
  ---
  AlsaDevices:
   total 0
   crw-rw---- 1 root audio 116,  1 Feb  3 18:41 seq
   crw-rw---- 1 root audio 116, 33 Feb  3 18:41 timer
  AplayDevices: Error: [Errno 2] No such file or directory
  ApportVersion: 2.14.1-0ubuntu3.19
  Architecture: amd64
  ArecordDevices: Error: [Errno 2] No such file or directory
  AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
  CRDA: Error: [Errno 2] No such file or directory
  DistroRelease: Ubuntu 14.04
  HibernationDevice: RESUME=/dev/mapper/data-swap
  InstallationDate: Installed on 2015-07-11 (210 days ago)
  InstallationMedia: Ubuntu-Server 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2)
  MachineType: Silicon Mechanics Storform iServ R515.v2.1
  Package: linux (not installed)
  PciMultimedia:

  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB: 0 VESA VGA
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-76-generic root=/dev/mapper/data-os ro elevator=noop console=ttyS1,115200n8 console=tty1 transparent_hugepage=always nomdmonddf nomdmonisw
  ProcVersionSignature: Ubuntu 3.13.0-76.120-generic 3.13.11-ckt30
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-76-generic N/A
   linux-backports-modules-3.13.0-76-generic  N/A
   linux-firmware                             1.127.20
  RfKill: Error: [Errno 2] No such file or directory
  Tags:  trusty
  Uname: Linux 3.13.0-76-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm dialout libvirtd lpadmin sudo users
  WifiSyslog:

  _MarkForUpload: True
  dmi.bios.date: 05/15/2012
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: 2.0c
  dmi.board.asset.tag: 1234567890
  dmi.board.name: X8DT6
  dmi.board.vendor: Supermicro
  dmi.board.version: 1234567890
  dmi.chassis.asset.tag: To Be Filled By O.E.M.
  dmi.chassis.type: 17
  dmi.chassis.vendor: Supermicro
  dmi.chassis.version: 1234567890
  dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2.0c:bd05/15/2012:svnSiliconMechanics:pnStorformiServR515.v2.1:pvr1234567890:rvnSupermicro:rnX8DT6:rvr1234567890:cvnSupermicro:ct17:cvr1234567890:
  dmi.product.name: Storform iServ R515.v2.1
  dmi.product.version: 1234567890
  dmi.sys.vendor: Silicon Mechanics

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