[Bug 1520192] Re: multipath-tools from Precise should have been fixed together with Trusty fixes

[Gábor Mészáros]

Steps taken to provoke the problem:
1.) deploy any VM instance using nova commands, that is booted from EMC VNX series SAN connected to compute using iscsi, dm-multipath
2.) unplug/disable network connectivity on any of the active paths
3.) check multipath -ll output for faulty failed path/device status.
4.) re-plug/enable network connectivity on the disabled paths
5.) check multipath -ll output for recovering to active enabled path/device status

Somtimes the problem occurs when disabling the interface, other times
only when re-enabling it.

Expected output for multipath -ll:
36006016047813400dd029f614896e511 dm-3 DGC     ,VRAID           
size=50G features='0' hwhandler='1 alua' wp=rw
`-+- policy='round-robin 0' prio=70 status=active
  |- 6:0:0:15 sdi   8:128  active ready  running
  |- 7:0:0:15 sdk   8:160  active ready  running
  |- 8:0:0:15 sdm   8:192  active ready  running
  `- 9:0:0:15 sdo   8:224  active ready  running

Actual output (even after several hours of waiting, with active traffic on storage):
36006016047813400dd029f614896e511 dm-3 DGC,VRAID
size=50G features='0' hwhandler='1 alua' wp=rw
`-+- policy='round-robin 0' prio=70 status=active
  |- 6:0:0:159 sdi 8:128 active ready  running
  |- 7:0:0:159 sdk 8:160 failed ready  running
  |- 8:0:0:159 sdm 8:192 active ready  running
  `- 9:0:0:159 sdo 8:224 failed ready  running

A previously discovered workaround for the problem can be achieved by reloading the multipath-tools service (or restarting, but multipath -r does not always fixes it).
The package with backported changes is confirmed to fix the issue, without having to reload the service.

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https://bugs.launchpad.net/bugs/1520192

Title:
  multipath-tools from Precise should have been fixed together with
  Trusty fixes

Status in multipath-tools package in Ubuntu:
  In Progress

Bug description:
  Precise multipath-tools MIGHT need fixes from trusty. This has already
  been proved in one iSCSI multipath installation where precise
  multipath, intermittently, connected to VNX storages show paths as:
  active/failed when it should show - even after the path check timeout
  - faulty/failed.

  * Improve description showing output *

  Using trusty multipath in Precise, the same environment does NOT suffer
  from this issue.

  Differences between both versions:

  #### LP: #1468897 - https://bugs.launchpad.net/bugs/1468897
  #### LP: #1386637 - https://bugs.launchpad.net/bugs/1386637

  - 0001-multipath-add-checker_timeout-default-config-option.patch
  - 0002-Make-params-variable-local.patch
  - 0003-libmultipath-Fix-possible-string-overflow.patch
  - 0004-Update-hwtable-factorization.patch
  - 0005-Fixup-strip-trailing-whitespaces-for-getuid-return-v.patch
  - 0006-Remove-sysfs_attr-cache.patch
  - 0007-Move-setup_thread_attr-to-uevent.c.patch
  - 0008-Use-lists-for-uevent-processing.patch
  - 0009-Start-uevent-service-handler-from-main-thread.patch
  - 0010-libmultipath-rework-sysfs-handling.patch
  - 0011-Rework-sysfs-device-handling-in-multipathd.patch
  - 0012-Only-check-offline-status-for-SCSI-devices.patch
  - 0013-Check-for-offline-path-in-get_prio.patch
  - 0014-libmultipath-Remove-duplicate-calls-to-path_offline.patch
  - 0015-Update-dev_loss_tmo-for-no_path_retry.patch
  - 0016-Reload-map-for-device-read-only-setting-changes.patch
  - 0017-multipath-get-right-sysfs-value-for-checker_timeout.patch
  - 0018-multipath-handle-offlined-paths.patch
  - 0019-multipath-fix-scsi-timeout-code.patch
  - 0020-multipath-make-tgt_node_name-work-for-iscsi-devices.patch
  - 0021-multipath-cleanup-dev_loss_tmo-issues.patch
  - 0022-Fix-for-setting-0-to-fast_io_fail.patch
  - 0023-Fix-fast_io_fail-capping.patch
  - 0024-multipath-enable-getting-uevents-through-libudev.patch
  - 0025-Use-devpath-as-argument-for-sysfs-functions.patch
  - 0026-multipathd-remove-references-to-sysfs_device.patch
  - 0027-multipathd-use-struct-path-as-argument-for-event-pro.patch
  - 0028-Add-global-udev-reference-pointer-to-config.patch
  - 0029-Use-udev-enumeration-during-discovery.patch
  - 0030-use-struct-udev_device-during-discovery.patch
  - 0031-More-debugging-output-when-synchronizing-path-states.patch
  - 0032-Use-struct-udev_device-instead-of-sysdev.patch
  - 0033-discovery-Fixup-cciss-discovery.patch
  - 0035-Use-udev-devices-during-discovery.patch
  - 0036-Remove-all-references-to-hand-craftes-sysfs-code.patch
  - 0037-multipath-libudev-cleanup-and-bugfixes.patch
  - 0038-multipath-check-if-a-device-belongs-to-multipath.patch
  - 0039-multipath-and-wwids_file-multipath.conf-option.patch
  - 0040-multipath-Check-blacklists-as-soon-as-possible.patch
  - 0041-add-wwids-file-cleanup-options.patch
  - 0042-add-find_multipaths-option.patch

  #### LP: #1431650 - https://bugs.launchpad.net/bugs/1431650

  - Added debian/patches/0015-shared-lock-for-udev.patch

  #### LP: #1441930 - https://bugs.launchpad.net/bugs/1441930

  - Support disks with non 512-byte sectors

  #### LP: #1435706 - https://bugs.launchpad.net/bugs/1435706 ( GOOD
  CANDIDATE )

  - Correctly write FC timeout attributes to sysfs.

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