Commit 415e72d0 authored by NeilBrown's avatar NeilBrown
Browse files

md/raid5: Allow recovered part of partially recovered devices to be in-sync 



During a recovery of reshape the early part of some devices might be
in-sync while the later parts are not.
We we know we are looking at an early part it is good to treat that
part as in-sync for stripe calculations.

This is particularly important for a reshape which suffers device
failure.  Treating the data as in-sync can mean the difference between
data-safety and data-loss.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 674806d6

drivers/md/raid5.c

+30 −12
Original line number Diff line number Diff line
@@ -3031,7 +3031,6 @@ static void handle_stripe5(struct stripe_head *sh) 
		mdk_rdev_t *rdev;



		dev = &sh->dev[i];

		clear_bit(R5_Insync, &dev->flags);



		pr_debug("check %d: state 0x%lx toread %p read %p write %p "

			"written %p\n",	i, dev->flags, dev->toread, dev->read,
@@ -3068,17 +3067,27 @@ static void handle_stripe5(struct stripe_head *sh) 
			blocked_rdev = rdev;

			atomic_inc(&rdev->nr_pending);

		}

		if (!rdev || !test_bit(In_sync, &rdev->flags)) {

		clear_bit(R5_Insync, &dev->flags);

		if (!rdev)

			/* Not in-sync */;

		else if (test_bit(In_sync, &rdev->flags))

			set_bit(R5_Insync, &dev->flags);

		else {

			/* could be in-sync depending on recovery/reshape status */

			if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)

				set_bit(R5_Insync, &dev->flags);

		}

		if (!test_bit(R5_Insync, &dev->flags)) {

			/* The ReadError flag will just be confusing now */

			clear_bit(R5_ReadError, &dev->flags);

			clear_bit(R5_ReWrite, &dev->flags);

		}

		if (!rdev || !test_bit(In_sync, &rdev->flags)

		    || test_bit(R5_ReadError, &dev->flags)) {

		if (test_bit(R5_ReadError, &dev->flags))

			clear_bit(R5_Insync, &dev->flags);

		if (!test_bit(R5_Insync, &dev->flags)) {

			s.failed++;

			s.failed_num = i;

		} else

			set_bit(R5_Insync, &dev->flags);

		}

	}

	rcu_read_unlock();
@@ -3312,7 +3321,6 @@ static void handle_stripe6(struct stripe_head *sh) 
	for (i=disks; i--; ) {

		mdk_rdev_t *rdev;

		dev = &sh->dev[i];

		clear_bit(R5_Insync, &dev->flags);



		pr_debug("check %d: state 0x%lx read %p write %p written %p\n",

			i, dev->flags, dev->toread, dev->towrite, dev->written);
@@ -3350,18 +3358,28 @@ static void handle_stripe6(struct stripe_head *sh) 
			blocked_rdev = rdev;

			atomic_inc(&rdev->nr_pending);

		}

		if (!rdev || !test_bit(In_sync, &rdev->flags)) {

		clear_bit(R5_Insync, &dev->flags);

		if (!rdev)

			/* Not in-sync */;

		else if (test_bit(In_sync, &rdev->flags))

			set_bit(R5_Insync, &dev->flags);

		else {

			/* in sync if before recovery_offset */

			if (sh->sector + STRIPE_SECTORS <= rdev->recovery_offset)

				set_bit(R5_Insync, &dev->flags);

		}

		if (!test_bit(R5_Insync, &dev->flags)) {

			/* The ReadError flag will just be confusing now */

			clear_bit(R5_ReadError, &dev->flags);

			clear_bit(R5_ReWrite, &dev->flags);

		}

		if (!rdev || !test_bit(In_sync, &rdev->flags)

		    || test_bit(R5_ReadError, &dev->flags)) {

		if (test_bit(R5_ReadError, &dev->flags))

			clear_bit(R5_Insync, &dev->flags);

		if (!test_bit(R5_Insync, &dev->flags)) {

			if (s.failed < 2)

				r6s.failed_num[s.failed] = i;

			s.failed++;

		} else

			set_bit(R5_Insync, &dev->flags);

		}

	}

	rcu_read_unlock();

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