drbd: transfer log epoch numbers are now per resource

cherry-picked from drbd 9 devel branch.

In preparation of multiple connections, the "barrier number" or
"epoch number" needs to be tracked per-resource, not per connection.
The sequence number space will not be reset anymore.

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_int.h b/drivers/block/drbd/drbd_int.h
index 5b1789a..d7ca76c 100644 (file)
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -864,6 +864,7 @@ struct drbd_tconn {                 /* is a resource from the config file */
        spinlock_t epoch_lock;
        unsigned int epochs;
        enum write_ordering_e write_ordering;
+       atomic_t current_tle_nr;        /* transfer log epoch number */
 
        unsigned long last_reconnect_jif;
        struct drbd_thread receiver;

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 843d0af..bfe6975 100644 (file)
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -208,7 +208,7 @@ static int tl_init(struct drbd_tconn *tconn)
        INIT_LIST_HEAD(&b->requests);
        INIT_LIST_HEAD(&b->w.list);
        b->next = NULL;
-       b->br_number = 4711;
+       b->br_number = atomic_inc_return(&tconn->current_tle_nr);
        b->n_writes = 0;
        b->w.cb = NULL; /* if this is != NULL, we need to dec_ap_pending in tl_clear */
 
@@ -241,16 +241,13 @@ static void tl_cleanup(struct drbd_tconn *tconn)
  */
 void _tl_add_barrier(struct drbd_tconn *tconn, struct drbd_tl_epoch *new)
 {
-       struct drbd_tl_epoch *newest_before;
-
        INIT_LIST_HEAD(&new->requests);
        INIT_LIST_HEAD(&new->w.list);
        new->w.cb = NULL; /* if this is != NULL, we need to dec_ap_pending in tl_clear */
        new->next = NULL;
        new->n_writes = 0;
 
-       newest_before = tconn->newest_tle;
-       new->br_number = newest_before->br_number+1;
+       new->br_number = atomic_inc_return(&tconn->current_tle_nr);
        if (tconn->newest_tle != new) {
                tconn->newest_tle->next = new;
                tconn->newest_tle = new;
@@ -406,7 +403,7 @@ void _tl_restart(struct drbd_tconn *tconn, enum drbd_req_event what)
                                list_splice(&carry_reads, &b->requests);
                                INIT_LIST_HEAD(&b->w.list);
                                b->w.cb = NULL;
-                               b->br_number = net_random();
+                               b->br_number = atomic_inc_return(&tconn->current_tle_nr);
                                b->n_writes = 0;
 
                                *pn = b;

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 34e791d..a131174 100644 (file)
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -187,7 +187,7 @@ static void _about_to_complete_local_write(struct drbd_conf *mdev,
         */
        if (mdev->state.conn >= C_CONNECTED &&
            (s & RQ_NET_SENT) != 0 &&
-           req->epoch == mdev->tconn->newest_tle->br_number)
+           req->epoch == atomic_read(&mdev->tconn->current_tle_nr))
                queue_barrier(mdev);
 }
 
@@ -518,7 +518,7 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
                 * just after it grabs the req_lock */
                D_ASSERT(test_bit(CREATE_BARRIER, &mdev->tconn->flags) == 0);
 
-               req->epoch = mdev->tconn->newest_tle->br_number;
+               req->epoch = atomic_read(&mdev->tconn->current_tle_nr);
 
                /* increment size of current epoch */
                mdev->tconn->newest_tle->n_writes++;