md/raid5: Avoid BUG caused by multiple failures.
While preparing to write a stripe we keep the parity block or blocks
locked (R5_LOCKED) - towards the end of schedule_reconstruction.
If the array is discovered to have failed before this write completes
we can leave those blocks LOCKED, and init_stripe will notice that a
free stripe still has a locked block and will complain.
So clear the R5_LOCKED flag in handle_failed_stripe, and demote the
'BUG' to a 'WARN_ON'.
Signed-off-by: NeilBrown <neilb@suse.de>
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index a81eca6..b874f42 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -340,7 +340,7 @@
(unsigned long long)sh->sector, i, dev->toread,
dev->read, dev->towrite, dev->written,
test_bit(R5_LOCKED, &dev->flags));
- BUG();
+ WARN_ON(1);
}
dev->flags = 0;
raid5_build_block(sh, i, previous);
@@ -2301,6 +2301,10 @@
if (bitmap_end)
bitmap_endwrite(conf->mddev->bitmap, sh->sector,
STRIPE_SECTORS, 0, 0);
+ /* If we were in the middle of a write the parity block might
+ * still be locked - so just clear all R5_LOCKED flags
+ */
+ clear_bit(R5_LOCKED, &sh->dev[i].flags);
}
if (test_and_clear_bit(STRIPE_FULL_WRITE, &sh->state))