btrfs: don't report readahead errors and don't update statistics

commit 0cc068e6ee59c1fffbfa977d8bf868b7551d80ac upstream.

As readahead is an optimization, all errors are usually filtered out,
but still properly handled when the real read call is done. The commit
5e9d398240b2 ("btrfs: readpages() should submit IO as read-ahead") added
REQ_RAHEAD to readpages() because that's only used for readahead
(despite what one would expect from the callback name).

This causes a flood of messages and inflated read error stats, so skip
reporting in case it's readahead.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202403
Reported-by: LimeTech <tomm@lime-technology.com>
Fixes: 5e9d398240b2 ("btrfs: readpages() should submit IO as read-ahead")
CC: stable@vger.kernel.org # 4.19+
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index c13f6218251384f5924d9bd2f70701f4972f0780..207f4e87445dba9e32fa0e75d148669985c979f7 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6051,7 +6051,7 @@ static void btrfs_end_bio(struct bio *bio)
                                if (bio_op(bio) == REQ_OP_WRITE)
                                        btrfs_dev_stat_inc_and_print(dev,
                                                BTRFS_DEV_STAT_WRITE_ERRS);
-                               else
+                               else if (!(bio->bi_opf & REQ_RAHEAD))
                                        btrfs_dev_stat_inc_and_print(dev,
                                                BTRFS_DEV_STAT_READ_ERRS);
                                if (bio->bi_opf & REQ_PREFLUSH)