path: root/drivers/block/drbd/drbd_req.c
diff options
authorLars Ellenberg <lars.ellenberg@linbit.com>2012-09-03 14:08:35 +0200
committerPhilipp Reisner <philipp.reisner@linbit.com>2012-11-09 14:11:37 +0100
commit70f17b6bd18dfe33f40db7573baa663b866be6ba (patch)
tree43e12531930774a6b1814a065441ca0ee1fce7df /drivers/block/drbd/drbd_req.c
parent76590cd1fc338fd1c50f7121636db421deb8b881 (diff)
drbd: differentiate early and later "postponing" of requests
We use the RQ_POSTPONED flag to mark a request for several reasons. It may be a conflicting request in a dual-primary setup, where conflict detection and resolution on the peer decided that this request needs to be re-submitted, it needs to re-enter drbd_make_request() to fix the data divergence caused by these conflicting, partially overlapping, quasi-simultaneous requests. In this case we need to mark the corresponding area as out-of-sync, before we call drbd_al_complete_io(). We also use the RQ_POSTPONED flag to just "push back" a request, before even processing it, if IO is suspended for some reason. In this case, as this request was neither submitted nor sent yet, we must not touch the bitmap. Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Diffstat (limited to 'drivers/block/drbd/drbd_req.c')
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index d1d17fcd923..e307890e6af 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -123,7 +123,14 @@ void drbd_req_destroy(struct kref *kref)
* (local only or remote failed).
* Other places where we set out-of-sync:
* READ with local io-error */
- if (!(s & RQ_POSTPONED)) {
+ /* There is a special case:
+ * we may notice late that IO was suspended,
+ * and postpone, or schedule for retry, a write,
+ * before it even was submitted or sent.
+ * In that case we do not want to touch the bitmap at all.
+ */
if (!(s & RQ_NET_OK) || !(s & RQ_LOCAL_OK))
drbd_set_out_of_sync(mdev, req->i.sector, req->i.size);