Btrfs: add device counters for detected IO and checksum errors

The goal is to detect when drives start to get an increased error rate,
when drives should be replaced soon. Therefore statistic counters are
added that count IO errors (read, write and flush). Additionally, the
software detected errors like checksum errors and corrupted blocks are
counted.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>

1 files changed, 16 insertions, 2 deletions

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 69a527c7a0b3..b3692c1373aa 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1913,6 +1913,7 @@ int repair_io_failure(struct btrfs_mapping_tree *map_tree, u64 start,
         if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
                 /* try to remap that extent elsewhere? */
                 bio_put(bio);
+                btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
                 return -EIO;
         }
 
@@ -2327,10 +2328,23 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
                 if (uptodate && tree->ops && tree->ops->readpage_end_io_hook) {
                         ret = tree->ops->readpage_end_io_hook(page, start, end,
                                                               state, mirror);
-                        if (ret)
+                        if (ret) {
+                                /* no IO indicated but software detected errors
+                                 * in the block, either checksum errors or
+                                 * issues with the contents */
+                                struct btrfs_root *root =
+                                        BTRFS_I(page->mapping->host)->root;
+                                struct btrfs_device *device;
+
                                 uptodate = 0;
-                        else
+                                device = btrfs_find_device_for_logical(
+                                                root, start, mirror);
+                                if (device)
+                                        btrfs_dev_stat_inc_and_print(device,
+                                                BTRFS_DEV_STAT_CORRUPTION_ERRS);
+                        } else {
                                 clean_io_failure(start, page);
+                        }
                 }
 
                 if (!uptodate && tree->ops && tree->ops->readpage_io_failed_hook) {