queue-5.0/btrfs-don-t-report-readahead-errors-and-don-t-update-statistics.patch

   1 From 0cc068e6ee59c1fffbfa977d8bf868b7551d80ac Mon Sep 17 00:00:00 2001
   2 From: David Sterba <dsterba@suse.com>
   3 Date: Thu, 7 Mar 2019 15:40:50 +0100
   4 Subject: btrfs: don't report readahead errors and don't update statistics
   5
   6 From: David Sterba <dsterba@suse.com>
   7
   8 commit 0cc068e6ee59c1fffbfa977d8bf868b7551d80ac upstream.
   9
  10 As readahead is an optimization, all errors are usually filtered out,
  11 but still properly handled when the real read call is done. The commit
  12 5e9d398240b2 ("btrfs: readpages() should submit IO as read-ahead") added
  13 REQ_RAHEAD to readpages() because that's only used for readahead
  14 (despite what one would expect from the callback name).
  15
  16 This causes a flood of messages and inflated read error stats, so skip
  17 reporting in case it's readahead.
  18
  19 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202403
  20 Reported-by: LimeTech <tomm@lime-technology.com>
  21 Fixes: 5e9d398240b2 ("btrfs: readpages() should submit IO as read-ahead")
  22 CC: stable@vger.kernel.org # 4.19+
  23 Signed-off-by: David Sterba <dsterba@suse.com>
  24 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  25
  26 ---
  27  fs/btrfs/volumes.c |    2 +-
  28  1 file changed, 1 insertion(+), 1 deletion(-)
  29
  30 --- a/fs/btrfs/volumes.c
  31 +++ b/fs/btrfs/volumes.c
  32 @@ -6413,7 +6413,7 @@ static void btrfs_end_bio(struct bio *bi
  33                                 if (bio_op(bio) == REQ_OP_WRITE)
  34                                         btrfs_dev_stat_inc_and_print(dev,
  35                                                 BTRFS_DEV_STAT_WRITE_ERRS);
  36 -                               else
  37 +                               else if (!(bio->bi_opf & REQ_RAHEAD))
  38                                         btrfs_dev_stat_inc_and_print(dev,
  39                                                 BTRFS_DEV_STAT_READ_ERRS);
  40                                 if (bio->bi_opf & REQ_PREFLUSH)