releases/4.18.14/dm-cache-metadata-ignore-hints-array-being-too-small-during-resize.patch

   1 From 4561ffca88c546f96367f94b8f1e4715a9c62314 Mon Sep 17 00:00:00 2001
   2 From: Joe Thornber <ejt@redhat.com>
   3 Date: Mon, 24 Sep 2018 16:19:30 -0400
   4 Subject: dm cache metadata: ignore hints array being too small during resize
   5
   6 From: Joe Thornber <ejt@redhat.com>
   7
   8 commit 4561ffca88c546f96367f94b8f1e4715a9c62314 upstream.
   9
  10 Commit fd2fa9541 ("dm cache metadata: save in-core policy_hint_size to
  11 on-disk superblock") enabled previously written policy hints to be
  12 used after a cache is reactivated.  But in doing so the cache
  13 metadata's hint array was left exposed to out of bounds access because
  14 on resize the metadata's on-disk hint array wasn't ever extended.
  15
  16 Fix this by ignoring that there are no on-disk hints associated with the
  17 newly added cache blocks.  An expanded on-disk hint array is later
  18 rewritten upon the next clean shutdown of the cache.
  19
  20 Fixes: fd2fa9541 ("dm cache metadata: save in-core policy_hint_size to on-disk superblock")
  21 Cc: stable@vger.kernel.org
  22 Signed-off-by: Joe Thornber <ejt@redhat.com>
  23 Signed-off-by: Mike Snitzer <snitzer@redhat.com>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25
  26 ---
  27  drivers/md/dm-cache-metadata.c |    4 ++--
  28  1 file changed, 2 insertions(+), 2 deletions(-)
  29
  30 --- a/drivers/md/dm-cache-metadata.c
  31 +++ b/drivers/md/dm-cache-metadata.c
  32 @@ -1455,8 +1455,8 @@ static int __load_mappings(struct dm_cac
  33                 if (hints_valid) {
  34                         r = dm_array_cursor_next(&cmd->hint_cursor);
  35                         if (r) {
  36 -                               DMERR("dm_array_cursor_next for hint failed");
  37 -                               goto out;
  38 +                               dm_array_cursor_end(&cmd->hint_cursor);
  39 +                               hints_valid = false;
  40                         }
  41                 }
  42