Commit 8cfa7b0f authored by NeilBrown's avatar NeilBrown
Browse files

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: default avatarNeilBrown <neilb@suse.de>
parent cbea2170

drivers/md/raid5.c

+5 −1
Original line number Diff line number Diff line
@@ -340,7 +340,7 @@ static void init_stripe(struct stripe_head *sh, sector_t sector, int previous) 
			       (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 @@ handle_failed_stripe(raid5_conf_t *conf, struct stripe_head *sh, 
		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))