btrfs scrub: added unverified_errors

In normal operation, scrub is reading data sequentially in large portions.
In case of an i/o error, we try to find the corrupted area(s) by issuing
page sized read requests. With this commit we increment the
unverified_errors counter if all of the small size requests succeed.

Userland patches carrying such conspicous events to the administrator should
already be around.

Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>

diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index a8d03d5..35099fa 100644 (file)
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -201,18 +201,25 @@ nomem:
  * recheck_error gets called for every page in the bio, even though only
  * one may be bad
  */
-static void scrub_recheck_error(struct scrub_bio *sbio, int ix)
+static int scrub_recheck_error(struct scrub_bio *sbio, int ix)
 {
+       struct scrub_dev *sdev = sbio->sdev;
+       u64 sector = (sbio->physical + ix * PAGE_SIZE) >> 9;
+
        if (sbio->err) {
-               if (scrub_fixup_io(READ, sbio->sdev->dev->bdev,
-                                  (sbio->physical + ix * PAGE_SIZE) >> 9,
+               if (scrub_fixup_io(READ, sbio->sdev->dev->bdev, sector,
                                   sbio->bio->bi_io_vec[ix].bv_page) == 0) {
                        if (scrub_fixup_check(sbio, ix) == 0)
-                               return;
+                               return 0;
                }
        }
 
+       spin_lock(&sdev->stat_lock);
+       ++sdev->stat.read_errors;
+       spin_unlock(&sdev->stat_lock);
+
        scrub_fixup(sbio, ix);
+       return 1;
 }
 
 static int scrub_fixup_check(struct scrub_bio *sbio, int ix)
@@ -382,8 +389,14 @@ static void scrub_checksum(struct btrfs_work *work)
        int ret;
 
        if (sbio->err) {
+               ret = 0;
                for (i = 0; i < sbio->count; ++i)
-                       scrub_recheck_error(sbio, i);
+                       ret |= scrub_recheck_error(sbio, i);
+               if (!ret) {
+                       spin_lock(&sdev->stat_lock);
+                       ++sdev->stat.unverified_errors;
+                       spin_unlock(&sdev->stat_lock);
+               }
 
                sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
                sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
@@ -396,10 +409,6 @@ static void scrub_checksum(struct btrfs_work *work)
                        bi->bv_offset = 0;
                        bi->bv_len = PAGE_SIZE;
                }
-
-               spin_lock(&sdev->stat_lock);
-               ++sdev->stat.read_errors;
-               spin_unlock(&sdev->stat_lock);
                goto out;
        }
        for (i = 0; i < sbio->count; ++i) {
@@ -420,8 +429,14 @@ static void scrub_checksum(struct btrfs_work *work)
                        WARN_ON(1);
                }
                kunmap_atomic(buffer, KM_USER0);
-               if (ret)
-                       scrub_recheck_error(sbio, i);
+               if (ret) {
+                       ret = scrub_recheck_error(sbio, i);
+                       if (!ret) {
+                               spin_lock(&sdev->stat_lock);
+                               ++sdev->stat.unverified_errors;
+                               spin_unlock(&sdev->stat_lock);
+                       }
+               }
        }
 
 out: