Do not sync peer OSDs before listing

Sync before listing was added to wait for all PG writes possibly left in queue
from the previous master to finish before listing it

But in fact it may block the cluster when EC is used and some unstable writes
are left in the queue - they block journal flushing, rollback/stabilize is
required to unblock them, but rollback/stabilize may only happen after PG is
peered. But peering needs listings, listings are requested only after sync, and
sync itself waits for currently blocked writes waiting in the queue

src/blockstore_impl.cpp

@@ -583,7 +583,7 @@ void blockstore_impl_t::process_list(blockstore_op_t *op)
                         replace_stable(dirty_it->first.oid, 0, clean_stable_count, stable_count, stable);
                     }
                 }
-                else if (IS_STABLE(dirty_it->second.state))
+                else if (IS_STABLE(dirty_it->second.state) || (dirty_it->second.state & BS_ST_INSTANT))
                 {
                     // First try to replace a clean stable version in the first part of the list
                     if (!replace_stable(dirty_it->first.oid, dirty_it->first.version, 0, clean_stable_count, stable))

src/blockstore_write.cpp

@@ -115,8 +115,8 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
     else if (!wait_del)
         printf("Write %lx:%lx v%lu offset=%u len=%u\n", op->oid.inode, op->oid.stripe, op->version, op->offset, op->len);
 #endif
-    // FIXME No strict need to add it into dirty_db here, it's just left
-    // from the previous implementation where reads waited for writes
+    // No strict need to add it into dirty_db here except maybe for listings to return
+    // correct data when there are inflight operations in the queue
     uint32_t state;
     if (is_del)
         state = BS_ST_DELETE | BS_ST_IN_FLIGHT;

src/osd.h

@@ -205,7 +205,6 @@ class osd_t
     bool check_peer_config(osd_client_t *cl, json11::Json conf);
     void repeer_pgs(osd_num_t osd_num);
     void start_pg_peering(pg_t & pg);
-    void submit_sync_and_list_subop(osd_num_t role_osd, pg_peering_state_t *ps);
     void submit_list_subop(osd_num_t role_osd, pg_peering_state_t *ps);
     void discard_list_subop(osd_op_t *list_op);
     bool stop_pg(pg_t & pg);

src/osd_peering.cpp

@@ -311,82 +311,11 @@ void osd_t::start_pg_peering(pg_t & pg)
         {
             continue;
         }
-        submit_sync_and_list_subop(peer_osd, pg.peering_state);
+        submit_list_subop(peer_osd, pg.peering_state);
     }
     ringloop->wakeup();
 }
 
-void osd_t::submit_sync_and_list_subop(osd_num_t role_osd, pg_peering_state_t *ps)
-{
-    // Sync before listing, if not readonly
-    if (readonly)
-    {
-        submit_list_subop(role_osd, ps);
-    }
-    else if (role_osd == this->osd_num)
-    {
-        // Self
-        osd_op_t *op = new osd_op_t();
-        op->op_type = 0;
-        op->peer_fd = SELF_FD;
-        clock_gettime(CLOCK_REALTIME, &op->tv_begin);
-        op->bs_op = new blockstore_op_t();
-        op->bs_op->opcode = BS_OP_SYNC;
-        op->bs_op->callback = [this, ps, op, role_osd](blockstore_op_t *bs_op)
-        {
-            if (bs_op->retval < 0)
-            {
-                printf("Local OP_SYNC failed: %d (%s)\n", bs_op->retval, strerror(-bs_op->retval));
-                force_stop(1);
-                return;
-            }
-            add_bs_subop_stats(op);
-            delete op->bs_op;
-            op->bs_op = NULL;
-            delete op;
-            ps->list_ops.erase(role_osd);
-            submit_list_subop(role_osd, ps);
-        };
-        ps->list_ops[role_osd] = op;
-        bs->enqueue_op(op->bs_op);
-    }
-    else
-    {
-        // Peer
-        auto & cl = msgr.clients.at(msgr.osd_peer_fds.at(role_osd));
-        osd_op_t *op = new osd_op_t();
-        op->op_type = OSD_OP_OUT;
-        op->peer_fd = cl->peer_fd;
-        op->req = (osd_any_op_t){
-            .sec_sync = {
-                .header = {
-                    .magic = SECONDARY_OSD_OP_MAGIC,
-                    .id = msgr.next_subop_id++,
-                    .opcode = OSD_OP_SEC_SYNC,
-                },
-            },
-        };
-        op->callback = [this, ps, role_osd](osd_op_t *op)
-        {
-            if (op->reply.hdr.retval < 0)
-            {
-                // FIXME: Mark peer as failed and don't reconnect immediately after dropping the connection
-                printf("Failed to sync OSD %lu: %ld (%s), disconnecting peer\n", role_osd, op->reply.hdr.retval, strerror(-op->reply.hdr.retval));
-                int fail_fd = op->peer_fd;
-                ps->list_ops.erase(role_osd);
-                delete op;
-                msgr.stop_client(fail_fd);
-                return;
-            }
-            delete op;
-            ps->list_ops.erase(role_osd);
-            submit_list_subop(role_osd, ps);
-        };
-        ps->list_ops[role_osd] = op;
-        msgr.outbox_push(op);
-    }
-}
-
 void osd_t::submit_list_subop(osd_num_t role_osd, pg_peering_state_t *ps)
 {
     if (role_osd == this->osd_num)