md/raid10: Don't skip more than 1 bitmap-chunk at a time during recovery.
When doing recovery on a raid10 with a write-intent bitmap, we only
need to recovery chunks that are flagged in the bitmap.
However if we choose to skip a chunk as it isn't flag, the code
currently skips the whole raid10-chunk, thus it might not recovery
some blocks that need recovering.
This patch fixes it.
In case that is confusing, it might help to understand that there
is a 'raid10 chunk size' which guides how data is distributed across
the devices, and a 'bitmap chunk size' which says how much data
corresponds to a single bit in the bitmap.
This bug only affects cases where the bitmap chunk size is smaller
than the raid10 chunk size.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 6736d6d..118f89e 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2010,13 +2010,13 @@
/* There is nowhere to write, so all non-sync
* drives must be failed, so try the next chunk...
*/
- {
- sector_t sec = max_sector - sector_nr;
- sectors_skipped += sec;
+ if (sector_nr + max_sync < max_sector)
+ max_sector = sector_nr + max_sync;
+
+ sectors_skipped += (max_sector - sector_nr);
chunks_skipped ++;
sector_nr = max_sector;
goto skipped;
- }
}
static int run(mddev_t *mddev)