drbd: Track all IO requests on the TL, not writes only

With that the drbd_fail_pending_reads() function becomes obsolete.

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

4 files changed, 23 insertions, 47 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index a9bc6bc62400..a86e6f1ff7f4 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -401,6 +401,8 @@ void tl_clear(struct drbd_conf *mdev)
         /* ensure bit indicating barrier is required is clear */
         clear_bit(CREATE_BARRIER, &mdev->flags);
 
+        memset(mdev->app_reads_hash, 0, APP_R_HSIZE*sizeof(void *));
+
         spin_unlock_irq(&mdev->req_lock);
 }
 
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 081522d3c742..88a5e1f4ec1d 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3666,41 +3666,6 @@ static void drbdd(struct drbd_conf *mdev)
         }
 }
 
-static void drbd_fail_pending_reads(struct drbd_conf *mdev)
-{
-        struct hlist_head *slot;
-        struct hlist_node *pos;
-        struct hlist_node *tmp;
-        struct drbd_request *req;
-        int i;
-
-        /*
-         * Application READ requests
-         */
-        spin_lock_irq(&mdev->req_lock);
-        for (i = 0; i < APP_R_HSIZE; i++) {
-                slot = mdev->app_reads_hash+i;
-                hlist_for_each_entry_safe(req, pos, tmp, slot, colision) {
-                        /* it may (but should not any longer!)
-                         * be on the work queue; if that assert triggers,
-                         * we need to also grab the
-                         * spin_lock_irq(&mdev->data.work.q_lock);
-                         * and list_del_init here. */
-                        D_ASSERT(list_empty(&req->w.list));
-                        /* It would be nice to complete outside of spinlock.
-                         * But this is easier for now. */
-                        _req_mod(req, connection_lost_while_pending);
-                }
-        }
-        for (i = 0; i < APP_R_HSIZE; i++)
-                if (!hlist_empty(mdev->app_reads_hash+i))
-                        dev_warn(DEV, "ASSERT FAILED: app_reads_hash[%d].first: "
-                                "%p, should be NULL\n", i, mdev->app_reads_hash[i].first);
-
-        memset(mdev->app_reads_hash, 0, APP_R_HSIZE*sizeof(void *));
-        spin_unlock_irq(&mdev->req_lock);
-}
-
 void drbd_flush_workqueue(struct drbd_conf *mdev)
 {
         struct drbd_wq_barrier barr;
@@ -3770,8 +3735,6 @@ static void drbd_disconnect(struct drbd_conf *mdev)
         if (!mdev->state.susp)
                 tl_clear(mdev);
 
-        drbd_fail_pending_reads(mdev);
-
         dev_info(DEV, "Connection closed\n");
 
         drbd_md_sync(mdev);
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 976d7941f71e..4a30e2cae56d 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -59,17 +59,19 @@ static void _drbd_end_io_acct(struct drbd_conf *mdev, struct drbd_request *req)
 static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const int rw)
 {
         const unsigned long s = req->rq_state;
+
+        /* remove it from the transfer log.
+         * well, only if it had been there in the first
+         * place... if it had not (local only or conflicting
+         * and never sent), it should still be "empty" as
+         * initialized in drbd_req_new(), so we can list_del() it
+         * here unconditionally */
+        list_del(&req->tl_requests);
+
         /* if it was a write, we may have to set the corresponding
          * bit(s) out-of-sync first. If it had a local part, we need to
          * release the reference to the activity log. */
         if (rw == WRITE) {
-                /* remove it from the transfer log.
-                 * well, only if it had been there in the first
-                 * place... if it had not (local only or conflicting
-                 * and never sent), it should still be "empty" as
-                 * initialized in drbd_req_new(), so we can list_del() it
-                 * here unconditionally */
-                list_del(&req->tl_requests);
                 /* Set out-of-sync unless both OK flags are set
                  * (local only or remote failed).
                  * Other places where we set out-of-sync:
@@ -517,8 +519,6 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 D_ASSERT(test_bit(CREATE_BARRIER, &mdev->flags) == 0);
 
                 req->epoch = mdev->newest_tle->br_number;
-                list_add_tail(&req->tl_requests,
-                                &mdev->newest_tle->requests);
 
                 /* increment size of current epoch */
                 mdev->newest_tle->n_writes++;
@@ -634,6 +634,9 @@ void __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 break;
 
         case barrier_acked:
+                if (!(req->rq_state & RQ_WRITE))
+                        break;
+
                 if (req->rq_state & RQ_NET_PENDING) {
                         /* barrier came in before all requests have been acked.
                          * this is bad, because if the connection is lost now,
@@ -892,6 +895,9 @@ allocate_barrier:
                 remote = 0;
         }
 
+
+        list_add_tail(&req->tl_requests, &mdev->newest_tle->requests);
+
         /* NOTE remote first: to get the concurrent write detection right,
          * we must register the request before start of local IO.  */
         if (remote) {
diff --git a/drivers/block/drbd/drbd_req.h b/drivers/block/drbd/drbd_req.h
index 02d575d24518..47b931fe0366 100644
--- a/drivers/block/drbd/drbd_req.h
+++ b/drivers/block/drbd/drbd_req.h
@@ -183,6 +183,9 @@ enum drbd_req_state_bits {
 
         /* keep this last, its for the RQ_NET_MASK */
         __RQ_NET_MAX,
+
+        /* Set when this is a write, clear for a read */
+        __RQ_WRITE,
 };
 
 #define RQ_LOCAL_PENDING   (1UL << __RQ_LOCAL_PENDING)
@@ -201,6 +204,8 @@ enum drbd_req_state_bits {
 /* 0x1f8 */
 #define RQ_NET_MASK        (((1UL << __RQ_NET_MAX)-1) & ~RQ_LOCAL_MASK)
 
+#define RQ_WRITE           (1UL << __RQ_WRITE)
+
 /* epoch entries */
 static inline
 struct hlist_head *ee_hash_slot(struct drbd_conf *mdev, sector_t sector)
@@ -253,7 +258,7 @@ static inline struct drbd_request *drbd_req_new(struct drbd_conf *mdev,
         if (likely(req)) {
                 bio = bio_clone(bio_src, GFP_NOIO); /* XXX cannot fail?? */
 
-                req->rq_state    = 0;
+                req->rq_state    = bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0;
                 req->mdev        = mdev;
                 req->master_bio  = bio_src;
                 req->private_bio = bio;