drbd: simplify retry path of failed READ requests
If a local or remote READ request fails, just push it back to the retry
workqueue. It will re-enter __drbd_make_request, and be re-assigned to
a suitable local or remote path, or failed, if we do not have access to
good data anymore.
This obsoletes w_read_retry_remote(),
and eliminates two goto...retry blocks in __req_mod()
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index f708aa1..1249672 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -263,7 +263,6 @@
{
const unsigned long s = req->rq_state;
struct drbd_conf *mdev = req->w.mdev;
- int rw = req->rq_state & RQ_WRITE ? WRITE : READ;
/* we must not complete the master bio, while it is
* still being processed by _drbd_send_zc_bio (drbd_send_dblock)
@@ -282,6 +281,8 @@
return;
if (req->master_bio) {
+ int rw = bio_rw(req->master_bio);
+
/* this is DATA_RECEIVED (remote read)
* or protocol C P_WRITE_ACK
* or protocol B P_RECV_ACK
@@ -326,7 +327,18 @@
/* Update disk stats */
_drbd_end_io_acct(mdev, req);
- if (!(s & RQ_POSTPONED)) {
+ /* if READ failed,
+ * have it be pushed back to the retry work queue,
+ * so it will re-enter __drbd_make_request,
+ * and be re-assigned to a suitable local or remote path,
+ * or failed if we do not have access to good data anymore.
+ * READA may fail.
+ * WRITE should have used all available paths already.
+ */
+ if (!ok && rw == READ)
+ req->rq_state |= RQ_POSTPONED;
+
+ if (!(req->rq_state & RQ_POSTPONED)) {
m->error = ok ? 0 : (error ?: -EIO);
m->bio = req->master_bio;
req->master_bio = NULL;
@@ -420,10 +432,7 @@
case ABORT_DISK_IO:
req->rq_state |= RQ_LOCAL_ABORTED;
- if (req->rq_state & RQ_WRITE)
- req_may_be_completed_not_susp(req, m);
- else
- goto goto_queue_for_net_read;
+ req_may_be_completed_not_susp(req, m);
break;
case WRITE_COMPLETED_WITH_ERROR:
@@ -451,20 +460,7 @@
D_ASSERT(!(req->rq_state & RQ_NET_MASK));
__drbd_chk_io_error(mdev, false);
-
- goto_queue_for_net_read:
-
- /* no point in retrying if there is no good remote data,
- * or we have no connection. */
- if (mdev->state.pdsk != D_UP_TO_DATE) {
- req_may_be_completed_not_susp(req, m);
- break;
- }
-
- /* _req_mod(req,TO_BE_SENT); oops, recursion... */
- req->rq_state |= RQ_NET_PENDING;
- inc_ap_pending(mdev);
- /* fall through: _req_mod(req,QUEUE_FOR_NET_READ); */
+ break;
case QUEUE_FOR_NET_READ:
/* READ or READA, and
@@ -483,10 +479,9 @@
set_bit(UNPLUG_REMOTE, &mdev->flags);
D_ASSERT(req->rq_state & RQ_NET_PENDING);
+ D_ASSERT((req->rq_state & RQ_LOCAL_MASK) == 0);
req->rq_state |= RQ_NET_QUEUED;
- req->w.cb = (req->rq_state & RQ_LOCAL_MASK)
- ? w_read_retry_remote
- : w_send_read_req;
+ req->w.cb = w_send_read_req;
drbd_queue_work(&mdev->tconn->data.work, &req->w);
break;
@@ -604,13 +599,7 @@
if (req->rq_state & RQ_NET_SENT && req->rq_state & RQ_WRITE)
atomic_sub(req->i.size >> 9, &mdev->ap_in_flight);
- /* if it is still queued, we may not complete it here.
- * it will be canceled soon. */
- if (!(req->rq_state & RQ_NET_QUEUED)) {
- if (p)
- goto goto_read_retry_local;
- req_may_be_completed(req, m); /* Allowed while state.susp */
- }
+ req_may_be_completed(req, m); /* Allowed while state.susp */
break;
case DISCARD_WRITE:
@@ -668,27 +657,11 @@
req->rq_state |= RQ_NET_DONE;
- if (!(req->rq_state & RQ_WRITE))
- goto goto_read_retry_local;
-
maybe_wakeup_conflicting_requests(req);
req_may_be_completed_not_susp(req, m);
/* else: done by HANDED_OVER_TO_NETWORK */
break;
- goto_read_retry_local:
- if (!drbd_may_do_local_read(mdev, req->i.sector, req->i.size)) {
- req_may_be_completed_not_susp(req, m);
- break;
- }
- D_ASSERT(!(req->rq_state & RQ_LOCAL_PENDING));
- req->rq_state |= RQ_LOCAL_PENDING;
-
- get_ldev(mdev);
- req->w.cb = w_restart_disk_io;
- drbd_queue_work(&mdev->tconn->data.work, &req->w);
- break;
-
case FAIL_FROZEN_DISK_IO:
if (!(req->rq_state & RQ_LOCAL_COMPLETED))
break;