zfs-patches/0052-Handle-zio_resume-and-mmp-off.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Olaf Faaland <faaland1@llnl.gov>
   3 Date: Thu, 8 Mar 2018 15:21:54 -0800
   4 Subject: [PATCH] Handle zio_resume and mmp => off
   5 MIME-Version: 1.0
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   8
   9 When multihost is disabled on a pool, and the pool is resumed via zpool
  10 clear, within a single cycle of the mmp thread's loop (e.g.  while it's
  11 in the cv_timedwait call), both mmp_last_write and mmp_delay should be
  12 updated.
  13
  14 The original code mistakenly treated the two cases as if they could not
  15 occur at the same time.
  16
  17 Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
  18 Reviewed-by: Tony Hutter <hutter2@llnl.gov>
  19 Signed-off-by: Olaf Faaland <faaland1@llnl.gov>
  20 Closes #7286
  21 (cherry picked from commit 267fd7b0f14251026c35d7ceab4fbbe2f06717e6)
  22 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  23 ---
  24  module/zfs/mmp.c | 14 ++++++++++----
  25  1 file changed, 10 insertions(+), 4 deletions(-)
  26
  27 diff --git a/module/zfs/mmp.c b/module/zfs/mmp.c
  28 index 634e48287..15eea41ab 100644
  29 --- a/module/zfs/mmp.c
  30 +++ b/module/zfs/mmp.c
  31 @@ -409,16 +409,22 @@ mmp_thread(spa_t *spa)
  32                 }
  33
  34                 /*
  35 -                * When MMP goes off => on, or spa goes suspended =>
  36 -                * !suspended, we know no writes occurred recently.  We
  37 -                * update mmp_last_write to give us some time to try.
  38 +                * MMP off => on, or suspended => !suspended:
  39 +                * No writes occurred recently.  Update mmp_last_write to give
  40 +                * us some time to try.
  41                  */
  42                 if ((!last_spa_multihost && multihost) ||
  43                     (last_spa_suspended && !suspended)) {
  44                         mutex_enter(&mmp->mmp_io_lock);
  45                         mmp->mmp_last_write = gethrtime();
  46                         mutex_exit(&mmp->mmp_io_lock);
  47 -               } else if (last_spa_multihost && !multihost) {
  48 +               }
  49 +
  50 +               /*
  51 +                * MMP on => off:
  52 +                * mmp_delay == 0 tells importing node to skip activity check.
  53 +                */
  54 +               if (last_spa_multihost && !multihost) {
  55                         mutex_enter(&mmp->mmp_io_lock);
  56                         mmp->mmp_delay = 0;
  57                         mutex_exit(&mmp->mmp_io_lock);
  58 --
  59 2.14.2
  60