drbd: Immediately allow completion of IOs, that wait for IO completions on a failed disk

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

3 files changed, 37 insertions, 11 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 8e489a6d022e..16969c2b96cd 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -368,6 +368,12 @@ static void _tl_restart(struct drbd_conf *mdev, enum drbd_req_event what)
                 }
                 tmp = b->next;
 
+                if (what == abort_disk_io) {
+                        /* Only walk the TL, leave barrier objects in place */
+                        b = tmp;
+                        continue;
+                }
+
                 if (n_writes) {
                         if (what == resend) {
                                 b->n_writes = n_writes;
@@ -1565,6 +1571,10 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
                 eh = mdev->ldev->dc.on_io_error;
                 was_io_error = test_and_clear_bit(WAS_IO_ERROR, &mdev->flags);
 
+                /* Immediately allow completion of all application IO, that waits
+                   for completion from the local disk. */
+                tl_restart(mdev, abort_disk_io);
+
                 /* current state still has to be D_FAILED,
                  * there is only one way out: to D_DISKLESS,
                  * and that may only happen after our put_ldev below. */
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 4a0f314086e5..1a8aac4b0c2f 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -214,8 +214,7 @@ void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m)
 {
         const unsigned long s = req->rq_state;
         struct drbd_conf *mdev = req->mdev;
-        /* only WRITES may end up here without a master bio (on barrier ack) */
-        int rw = req->master_bio ? bio_data_dir(req->master_bio) : WRITE;
+        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)
@@ -230,7 +229,7 @@ void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m)
                 return;
         if (s & RQ_NET_PENDING)
                 return;
-        if (s & RQ_LOCAL_PENDING)
+        if (s & RQ_LOCAL_PENDING && !(s & RQ_LOCAL_ABORTED))
                 return;
 
         if (req->master_bio) {
@@ -277,6 +276,9 @@ void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m)
                 req->master_bio = NULL;
         }
 
+        if (s & RQ_LOCAL_PENDING)
+                return;
+
         if ((s & RQ_NET_MASK) == 0 || (s & RQ_NET_DONE)) {
                 /* this is disconnected (local only) operation,
                  * or protocol C P_WRITE_ACK,
@@ -429,7 +431,7 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 break;
 
         case completed_ok:
-                if (bio_data_dir(req->master_bio) == WRITE)
+                if (req->rq_state & RQ_WRITE)
                         mdev->writ_cnt += req->size>>9;
                 else
                         mdev->read_cnt += req->size>>9;
@@ -441,6 +443,14 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 put_ldev(mdev);
                 break;
 
+        case abort_disk_io:
+                req->rq_state |= RQ_LOCAL_ABORTED;
+                if (req->rq_state & RQ_WRITE)
+                        _req_may_be_done_not_susp(req, m);
+                else
+                        goto goto_queue_for_net_read;
+                break;
+
         case write_completed_with_error:
                 req->rq_state |= RQ_LOCAL_COMPLETED;
                 req->rq_state &= ~RQ_LOCAL_PENDING;
@@ -469,6 +479,8 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 __drbd_chk_io_error(mdev, false);
                 put_ldev(mdev);
 
+        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) {
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index 74c5b9f14d61..3d2111919486 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -119,18 +119,21 @@ enum drbd_req_event {
  * same time, so we should hold the request lock anyways.
  */
 enum drbd_req_state_bits {
-        /* 210
-         * 000: no local possible
-         * 001: to be submitted
+        /* 3210
+         * 0000: no local possible
+         * 0001: to be submitted
          *    UNUSED, we could map: 011: submitted, completion still pending
-         * 110: completed ok
-         * 010: completed with error
+         * 0110: completed ok
+         * 0010: completed with error
+         * 1001: Aborted (before completion)
+         * 1x10: Aborted and completed -> free
          */
         __RQ_LOCAL_PENDING,
         __RQ_LOCAL_COMPLETED,
         __RQ_LOCAL_OK,
+        __RQ_LOCAL_ABORTED,
 
-        /* 76543
+        /* 87654
          * 00000: no network possible
          * 00001: to be send
          * 00011: to be send, on worker queue
@@ -200,8 +203,9 @@ enum drbd_req_state_bits {
 #define RQ_LOCAL_PENDING   (1UL << __RQ_LOCAL_PENDING)
 #define RQ_LOCAL_COMPLETED (1UL << __RQ_LOCAL_COMPLETED)
 #define RQ_LOCAL_OK        (1UL << __RQ_LOCAL_OK)
+#define RQ_LOCAL_ABORTED   (1UL << __RQ_LOCAL_ABORTED)
 
-#define RQ_LOCAL_MASK      ((RQ_LOCAL_OK << 1)-1) /* 0x07 */
+#define RQ_LOCAL_MASK      ((RQ_LOCAL_ABORTED << 1)-1)
 
 #define RQ_NET_PENDING     (1UL << __RQ_NET_PENDING)
 #define RQ_NET_QUEUED      (1UL << __RQ_NET_QUEUED)