zfs-patches/0024-Fix-racy-assignment-of-zcb.zcb_haderrors.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Chunwei Chen <david.chen@nutanix.com>
   3 Date: Thu, 1 Feb 2018 15:42:41 -0800
   4 Subject: [PATCH] Fix racy assignment of zcb.zcb_haderrors
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 zcb_haderrors will be modified in zdb_blkptr_done, which is
  10 asynchronous. So we must move this assignment after zio_wait.
  11
  12 Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
  13 Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
  14 Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
  15 Closes #7099
  16 (cherry picked from commit c797f0898ec11669427e2fc481118bc2e2d8ef3f)
  17 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  18 ---
  19  cmd/zdb/zdb.c | 10 ++++++++--
  20  1 file changed, 8 insertions(+), 2 deletions(-)
  21
  22 diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
  23 index 442685486..0cc1656a8 100644
  24 --- a/cmd/zdb/zdb.c
  25 +++ b/cmd/zdb/zdb.c
  26 @@ -3313,7 +3313,7 @@ dump_block_stats(spa_t *spa)
  27         uint64_t norm_alloc, norm_space, total_alloc, total_found;
  28         int flags = TRAVERSE_PRE | TRAVERSE_PREFETCH_METADATA | TRAVERSE_HARD;
  29         boolean_t leaks = B_FALSE;
  30 -       int e, c;
  31 +       int e, c, err;
  32         bp_embedded_type_t i;
  33
  34         (void) printf("\nTraversing all blocks %s%s%s%s%s...\n\n",
  35 @@ -3354,7 +3354,7 @@ dump_block_stats(spa_t *spa)
  36
  37         zcb.zcb_totalasize = metaslab_class_get_alloc(spa_normal_class(spa));
  38         zcb.zcb_start = zcb.zcb_lastprint = gethrtime();
  39 -       zcb.zcb_haderrors |= traverse_pool(spa, 0, flags, zdb_blkptr_cb, &zcb);
  40 +       err = traverse_pool(spa, 0, flags, zdb_blkptr_cb, &zcb);
  41
  42         /*
  43          * If we've traversed the data blocks then we need to wait for those
  44 @@ -3370,6 +3370,12 @@ dump_block_stats(spa_t *spa)
  45                 }
  46         }
  47
  48 +       /*
  49 +        * Done after zio_wait() since zcb_haderrors is modified in
  50 +        * zdb_blkptr_done()
  51 +        */
  52 +       zcb.zcb_haderrors |= err;
  53 +
  54         if (zcb.zcb_haderrors) {
  55                 (void) printf("\nError counts:\n\n");
  56                 (void) printf("\t%5s  %s\n", "errno", "count");
  57 --
  58 2.14.2
  59