From: Yu Kuai <yukuai3@xxxxxxxxxx>
The checking and handler of bad blocks appear many timers during
read_balance() in raid1 and raid10. This helper will be used in later
patches to simplify read_balance() a lot.
Co-developed-by: Paul Luse <paul.e.luse@xxxxxxxxxxxxxxx>
Signed-off-by: Paul Luse <paul.e.luse@xxxxxxxxxxxxxxx>
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
Reviewed-by: Xiao Ni <xni@xxxxxxxxxx>
---
drivers/md/raid1-10.c | 49 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 49 insertions(+)
diff --git a/drivers/md/raid1-10.c b/drivers/md/raid1-10.c
index 512746551f36..9bc0f0022a6c 100644
--- a/drivers/md/raid1-10.c
+++ b/drivers/md/raid1-10.c
@@ -227,3 +227,52 @@ static inline bool exceed_read_errors(struct mddev *mddev, struct md_rdev *rdev)
return false;
}
+
+/**
+ * raid1_check_read_range() - check a given read range for bad blocks,
+ * available read length is returned;
+ * @rdev: the rdev to read;
+ * @this_sector: read position;
+ * @len: read length;
+ *
+ * helper function for read_balance()
+ *
+ * 1) If there are no bad blocks in the range, @len is returned;
+ * 2) If the range are all bad blocks, 0 is returned;
+ * 3) If there are partial bad blocks:
+ * - If the bad block range starts after @this_sector, the length of first
+ * good region is returned;
+ * - If the bad block range starts before @this_sector, 0 is returned and
+ * the @len is updated to the offset into the region before we get to the
+ * good blocks;
+ */
+static inline int raid1_check_read_range(struct md_rdev *rdev,
+ sector_t this_sector, int *len)
+{
+ sector_t first_bad;
+ int bad_sectors;
+
+ /* no bad block overlap */
+ if (!is_badblock(rdev, this_sector, *len, &first_bad, &bad_sectors))
+ return *len;
+
+ /*
+ * bad block range starts offset into our range so we can return the
+ * number of sectors before the bad blocks start.
+ */
+ if (first_bad > this_sector)
+ return first_bad - this_sector;
+
+ /* read range is fully consumed by bad blocks. */
+ if (this_sector + *len <= first_bad + bad_sectors)
+ return 0;
+
+ /*
+ * final case, bad block range starts before or at the start of our
+ * range but does not cover our entire range so we still return 0 but
+ * update the length with the number of sectors before we get to the
+ * good ones.
+ */
+ *len = first_bad + bad_sectors - this_sector;
+ return 0;
+}
--
2.39.2
