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Commit 7074e4a7 authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Jens Axboe
Browse files

drbd: only fail empty flushes if no good data is reachable 



We completed empty flushes (blkdev_issue_flush()) with IO error
if we lost the local disk, even if we still have an established
replication link to a healthy remote disk.

Fix this to only report errors to upper layers,
if neither local nor remote data is reachable.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 2bd5ed5d

drivers/block/drbd/drbd_req.c

+8 −4
Original line number Diff line number Diff line
@@ -263,8 +263,7 @@ void drbd_req_complete(struct drbd_request *req, struct bio_and_error *m) 
		else

			root = &mdev->read_requests;

		drbd_remove_request_interval(root, req);

	} else if (!(s & RQ_POSTPONED))

		D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0);

	}



	/* Before we can signal completion to the upper layers,

	 * we may need to close the current transfer log epoch.
@@ -755,6 +754,11 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what, 
		D_ASSERT(req->rq_state & RQ_NET_PENDING);

		mod_rq_state(req, m, RQ_NET_PENDING, RQ_NET_OK|RQ_NET_DONE);

		break;



	case QUEUE_AS_DRBD_BARRIER:

		start_new_tl_epoch(mdev->tconn);

		mod_rq_state(req, m, 0, RQ_NET_OK|RQ_NET_DONE);

		break;

	};



	return rv;
@@ -975,8 +979,8 @@ static int drbd_process_write_request(struct drbd_request *req) 
		/* The only size==0 bios we expect are empty flushes. */

		D_ASSERT(req->master_bio->bi_rw & REQ_FLUSH);

		if (remote)

			start_new_tl_epoch(mdev->tconn);

		return 0;

			_req_mod(req, QUEUE_AS_DRBD_BARRIER);

		return remote;

	}



	if (!remote && !send_oos)

drivers/block/drbd/drbd_req.h

+8 −0
Original line number Diff line number Diff line
@@ -88,6 +88,14 @@ enum drbd_req_event { 
	QUEUE_FOR_NET_READ,

	QUEUE_FOR_SEND_OOS,



	/* An empty flush is queued as P_BARRIER,

	 * which will cause it to complete "successfully",

	 * even if the local disk flush failed.

	 *

	 * Just like "real" requests, empty flushes (blkdev_issue_flush()) will

	 * only see an error if neither local nor remote data is reachable. */

	QUEUE_AS_DRBD_BARRIER,



	SEND_CANCELED,

	SEND_FAILED,

	HANDED_OVER_TO_NETWORK,