btrfs: don't do repair validation for checksum errors

The purpose of the validation step is to distinguish between good and
bad sectors in a failed multi-sector read. If a multi-sector read
succeeded but some of those sectors had checksum errors, we don't need
to validate anything; we know the sectors with bad checksums need to be
repaired.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fcf2ff9ae4a8ccd9c4ba73faf877a8bd38a8bdb0..cf24b2855462745ed8fcf3b8a7f08897cfa63235 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2640,6 +2640,14 @@ static bool btrfs_io_needs_validation(struct inode *inode, struct bio *bio)
        u64 len = 0;
        int i;
 
+       /*
+        * If bi_status is BLK_STS_OK, then this was a checksum error, not an
+        * I/O error. In this case, we already know exactly which sector was
+        * bad, so we don't need to validate.
+        */
+       if (bio->bi_status == BLK_STS_OK)
+               return false;
+
        /*
         * We need to validate each sector individually if the failed I/O was
         * for multiple sectors.