Merging upstream version 18.2.3.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

16 files changed, 359 insertions, 113 deletions

diff --git a/src/osd/OSD.cc b/src/osd/OSD.cc
index c61e7d332..515eb6042 100644
--- a/src/osd/OSD.cc
+++ b/src/osd/OSD.cc
@@ -1703,7 +1703,7 @@ void OSDService::queue_recovery_context(
   epoch_t e = get_osdmap_epoch();
 
   uint64_t cost_for_queue = [this, cost] {
-    if (cct->_conf->osd_op_queue == "mclock_scheduler") {
+    if (op_queue_type_t::mClockScheduler == osd->osd_op_queue_type()) {
       return cost;
     } else {
       /* We retain this legacy behavior for WeightedPriorityQueue. It seems to
@@ -1726,14 +1726,32 @@ void OSDService::queue_recovery_context(
       e));
 }
 
-void OSDService::queue_for_snap_trim(PG *pg)
+void OSDService::queue_for_snap_trim(PG *pg, uint64_t cost_per_object)
 {
   dout(10) << "queueing " << *pg << " for snaptrim" << dendl;
+  uint64_t cost_for_queue = [this, cost_per_object] {
+    if (cct->_conf->osd_op_queue == "mclock_scheduler") {
+      /* The cost calculation is valid for most snap trim iterations except
+       * for the following cases:
+       * 1) The penultimate iteration which may return 1 object to trim, in
+       *    which case the cost will be off by a factor equivalent to the
+       *    average object size, and,
+       * 2) The final iteration which returns -ENOENT and performs clean-ups.
+       */
+      return cost_per_object * cct->_conf->osd_pg_max_concurrent_snap_trims;
+    } else {
+      /* We retain this legacy behavior for WeightedPriorityQueue.
+       * This branch should be removed after Squid.
+       */
+      return cct->_conf->osd_snap_trim_cost;
+    }
+  }();
+
   enqueue_back(
     OpSchedulerItem(
       unique_ptr<OpSchedulerItem::OpQueueable>(
 	new PGSnapTrim(pg->get_pgid(), pg->get_osdmap_epoch())),
-      cct->_conf->osd_snap_trim_cost,
+      cost_for_queue,
       cct->_conf->osd_snap_trim_priority,
       ceph_clock_now(),
       0,
@@ -1771,7 +1789,7 @@ int64_t OSDService::get_scrub_cost()
 {
 
   int64_t cost_for_queue = cct->_conf->osd_scrub_cost;
-  if (cct->_conf->osd_op_queue == "mclock_scheduler") {
+  if (op_queue_type_t::mClockScheduler == osd->osd_op_queue_type()) {
     cost_for_queue = cct->_conf->osd_scrub_event_cost *
                      cct->_conf->osd_shallow_scrub_chunk_max;
   }
@@ -2049,7 +2067,7 @@ void OSDService::_queue_for_recovery(
   ceph_assert(ceph_mutex_is_locked_by_me(recovery_lock));
 
   uint64_t cost_for_queue = [this, &reserved_pushes, &p] {
-    if (cct->_conf->osd_op_queue == "mclock_scheduler") {
+    if (op_queue_type_t::mClockScheduler == osd->osd_op_queue_type()) {
       return p.cost_per_object * reserved_pushes;
     } else {
       /* We retain this legacy behavior for WeightedPriorityQueue. It seems to
@@ -2092,6 +2110,22 @@ int heap(CephContext& cct,
 
 } // namespace ceph::osd_cmds
 
+void OSD::write_superblock(CephContext* cct, OSDSuperblock& sb, ObjectStore::Transaction& t)
+{
+  dout(10) << "write_superblock " << sb << dendl;
+
+  //hack: at minimum it's using the baseline feature set
+  if (!sb.compat_features.incompat.contains(CEPH_OSD_FEATURE_INCOMPAT_BASE))
+    sb.compat_features.incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_BASE);
+
+  bufferlist bl;
+  encode(sb, bl);
+  t.write(coll_t::meta(), OSD_SUPERBLOCK_GOBJECT, 0, bl.length(), bl);
+  std::map<std::string, ceph::buffer::list> attrs;
+  attrs.emplace(OSD_SUPERBLOCK_OMAP_KEY, bl);
+  t.omap_setkeys(coll_t::meta(), OSD_SUPERBLOCK_GOBJECT, attrs);
+}
+
 int OSD::mkfs(CephContext *cct,
 	      std::unique_ptr<ObjectStore> store,
 	      uuid_d fsid,
@@ -2153,15 +2187,11 @@ int OSD::mkfs(CephContext *cct,
     sb.osd_fsid = store->get_fsid();
     sb.whoami = whoami;
     sb.compat_features = get_osd_initial_compat_set();
-
-    bufferlist bl;
-    encode(sb, bl);
-
     ObjectStore::CollectionHandle ch = store->create_new_collection(
       coll_t::meta());
     ObjectStore::Transaction t;
     t.create_collection(coll_t::meta(), 0);
-    t.write(coll_t::meta(), OSD_SUPERBLOCK_GOBJECT, 0, bl.length(), bl);
+    write_superblock(cct, sb, t);
     ret = store->queue_transaction(ch, std::move(t));
     if (ret) {
       derr << "OSD::mkfs: error while writing OSD_SUPERBLOCK_GOBJECT: "
@@ -2385,13 +2415,55 @@ OSD::OSD(CephContext *cct_,
   trace_endpoint.copy_name(ss.str());
 #endif
 
+  // Determine scheduler type for this OSD
+  auto get_op_queue_type = [this, &conf = cct->_conf]() {
+    op_queue_type_t queue_type;
+    if (auto type = conf.get_val<std::string>("osd_op_queue");
+        type != "debug_random") {
+      if (auto qt = get_op_queue_type_by_name(type); qt.has_value()) {
+        queue_type = *qt;
+      } else {
+        // This should never happen
+        dout(0) << "Invalid value passed for 'osd_op_queue': " << type << dendl;
+        ceph_assert(0 == "Unsupported op queue type");
+      }
+    } else {
+      static const std::vector<op_queue_type_t> index_lookup = {
+        op_queue_type_t::mClockScheduler,
+        op_queue_type_t::WeightedPriorityQueue
+      };
+      std::mt19937 random_gen(std::random_device{}());
+      auto which = random_gen() % index_lookup.size();
+      queue_type = index_lookup[which];
+    }
+    return queue_type;
+  };
+  op_queue_type_t op_queue = get_op_queue_type();
+
+  // Determine op queue cutoff
+  auto get_op_queue_cut_off = [&conf = cct->_conf]() {
+    if (conf.get_val<std::string>("osd_op_queue_cut_off") == "debug_random") {
+      std::random_device rd;
+      std::mt19937 random_gen(rd());
+      return (random_gen() % 2 < 1) ? CEPH_MSG_PRIO_HIGH : CEPH_MSG_PRIO_LOW;
+    } else if (conf.get_val<std::string>("osd_op_queue_cut_off") == "high") {
+      return CEPH_MSG_PRIO_HIGH;
+    } else {
+      // default / catch-all is 'low'
+      return CEPH_MSG_PRIO_LOW;
+    }
+  };
+  unsigned op_queue_cut_off = get_op_queue_cut_off();
+
   // initialize shards
   num_shards = get_num_op_shards();
   for (uint32_t i = 0; i < num_shards; i++) {
     OSDShard *one_shard = new OSDShard(
       i,
       cct,
-      this);
+      this,
+      op_queue,
+      op_queue_cut_off);
     shards.push_back(one_shard);
   }
 }
@@ -3121,6 +3193,19 @@ will start to track new ops received afterwards.";
     scrub_purged_snaps();
   }
 
+  else if (prefix == "reset_purged_snaps_last") {
+    lock_guard l(osd_lock);
+    superblock.purged_snaps_last = 0;
+    ObjectStore::Transaction t;
+    dout(10) << __func__ << " updating superblock" << dendl;
+    write_superblock(cct, superblock, t);
+    ret = store->queue_transaction(service.meta_ch, std::move(t), nullptr);
+    if (ret < 0) {
+      ss << "Error writing superblock: " << cpp_strerror(ret);
+      goto out;
+    }
+  }
+
   else if (prefix == "dump_osd_network") {
     lock_guard l(osd_lock);
     int64_t value = 0;
@@ -3762,7 +3847,7 @@ int OSD::init()
     }
 
     ObjectStore::Transaction t;
-    write_superblock(t);
+    write_superblock(cct, superblock, t);
     r = store->queue_transaction(service.meta_ch, std::move(t));
     if (r < 0)
       goto out;
@@ -4300,6 +4385,11 @@ void OSD::final_init()
     "Scrub purged_snaps vs snapmapper index");
   ceph_assert(r == 0);
   r = admin_socket->register_command(
+    "reset_purged_snaps_last",
+    asok_hook,
+    "Reset the superblock's purged_snaps_last");
+  ceph_assert(r == 0);
+  r = admin_socket->register_command(
     "scrubdebug "						\
     "name=pgid,type=CephPgid "	                                \
     "name=cmd,type=CephChoices,strings=block|unblock|set|unset " \
@@ -4572,7 +4662,7 @@ int OSD::shutdown()
   superblock.mounted = service.get_boot_epoch();
   superblock.clean_thru = get_osdmap_epoch();
   ObjectStore::Transaction t;
-  write_superblock(t);
+  write_superblock(cct, superblock, t);
   int r = store->queue_transaction(service.meta_ch, std::move(t));
   if (r) {
     derr << "OSD::shutdown: error writing superblock: "
@@ -4769,31 +4859,81 @@ int OSD::update_crush_device_class()
   }
 }
 
-void OSD::write_superblock(ObjectStore::Transaction& t)
-{
-  dout(10) << "write_superblock " << superblock << dendl;
-
-  //hack: at minimum it's using the baseline feature set
-  if (!superblock.compat_features.incompat.contains(CEPH_OSD_FEATURE_INCOMPAT_BASE))
-    superblock.compat_features.incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_BASE);
-
-  bufferlist bl;
-  encode(superblock, bl);
-  t.write(coll_t::meta(), OSD_SUPERBLOCK_GOBJECT, 0, bl.length(), bl);
-}
 
 int OSD::read_superblock()
 {
+  // Read superblock from both object data and omap metadata
+  // for better robustness.
+  // Use the most recent superblock replica if obtained versions
+  // mismatch.
   bufferlist bl;
-  int r = store->read(service.meta_ch, OSD_SUPERBLOCK_GOBJECT, 0, 0, bl);
-  if (r < 0)
-    return r;
 
-  auto p = bl.cbegin();
-  decode(superblock, p);
+  set<string> keys;
+  keys.insert(OSD_SUPERBLOCK_OMAP_KEY);
+  map<string, bufferlist> vals;
+  OSDSuperblock super_omap;
+  OSDSuperblock super_disk;
+  int r_omap = store->omap_get_values(
+    service.meta_ch, OSD_SUPERBLOCK_GOBJECT, keys, &vals);
+  if (r_omap >= 0 && vals.size() > 0) {
+    try {
+      auto p = vals.begin()->second.cbegin();
+      decode(super_omap, p);
+    } catch(...) {
+      derr << __func__ << " omap replica is corrupted."
+            << dendl;
+      r_omap = -EFAULT;
+    }
+  } else {
+    derr << __func__ << " omap replica is missing."
+         << dendl;
+    r_omap = -ENOENT;
+  }
+  int r_disk = store->read(service.meta_ch, OSD_SUPERBLOCK_GOBJECT, 0, 0, bl);
+  if (r_disk >= 0) {
+    try {
+      auto p = bl.cbegin();
+      decode(super_disk, p);
+    } catch(...) {
+      derr << __func__ << " disk replica is corrupted."
+            << dendl;
+      r_disk = -EFAULT;
+    }
+  } else {
+    derr << __func__ << " disk replica is missing."
+         << dendl;
+    r_disk = -ENOENT;
+  }
 
-  dout(10) << "read_superblock " << superblock << dendl;
+  if (r_omap >= 0 && r_disk < 0) {
+    std::swap(superblock, super_omap);
+    dout(1) << __func__ << " got omap replica but failed to get disk one."
+            << dendl;
+  } else if (r_omap < 0 && r_disk >= 0) {
+    std::swap(superblock, super_disk);
+    dout(1) << __func__ << " got disk replica but failed to get omap one."
+            << dendl;
+  } else if (r_omap < 0 && r_disk < 0) {
+    // error to be logged by the caller
+    return -ENOENT;
+  } else {
+    std::swap(superblock, super_omap); // let omap be the primary source
+    if (superblock.current_epoch != super_disk.current_epoch) {
+      derr << __func__ << " got mismatching superblocks, omap:"
+           << superblock << " vs. disk:" << super_disk
+           << dendl;
+      if (superblock.current_epoch < super_disk.current_epoch) {
+        std::swap(superblock, super_disk);
+        dout(0) << __func__ << " using disk superblock"
+                << dendl;
+      } else {
+        dout(0) << __func__ << " using omap superblock"
+                << dendl;
+      }
+    }
+  }
 
+  dout(10) << "read_superblock " << superblock << dendl;
   return 0;
 }
 
@@ -6695,7 +6835,7 @@ void OSD::handle_get_purged_snaps_reply(MMonGetPurgedSnapsReply *m)
       m->purged_snaps);
   }
   superblock.purged_snaps_last = m->last;
-  write_superblock(t);
+  write_superblock(cct, superblock, t);
   store->queue_transaction(
     service.meta_ch,
     std::move(t));
@@ -7179,7 +7319,7 @@ void OSD::scrub_purged_snaps()
   dout(10) << __func__ << " done queueing pgs, updating superblock" << dendl;
   ObjectStore::Transaction t;
   superblock.last_purged_snaps_scrub = ceph_clock_now();
-  write_superblock(t);
+  write_superblock(cct, superblock, t);
   int tr = store->queue_transaction(service.meta_ch, std::move(t), nullptr);
   ceph_assert(tr == 0);
   if (is_active()) {
@@ -7892,7 +8032,7 @@ void OSD::trim_maps(epoch_t oldest, int nreceived, bool skip_maps)
     num++;
     if (num >= cct->_conf->osd_target_transaction_size && num >= nreceived) {
       service.publish_superblock(superblock);
-      write_superblock(t);
+      write_superblock(cct, superblock, t);
       int tr = store->queue_transaction(service.meta_ch, std::move(t), nullptr);
       ceph_assert(tr == 0);
       num = 0;
@@ -7908,7 +8048,7 @@ void OSD::trim_maps(epoch_t oldest, int nreceived, bool skip_maps)
   }
   if (num > 0) {
     service.publish_superblock(superblock);
-    write_superblock(t);
+    write_superblock(cct, superblock, t);
     int tr = store->queue_transaction(service.meta_ch, std::move(t), nullptr);
     ceph_assert(tr == 0);
   }
@@ -8220,7 +8360,19 @@ void OSD::handle_osd_map(MOSDMap *m)
   {
     bufferlist bl;
     ::encode(pg_num_history, bl);
-    t.write(coll_t::meta(), make_pg_num_history_oid(), 0, bl.length(), bl);
+    auto oid = make_pg_num_history_oid();
+    t.truncate(coll_t::meta(), oid, 0); // we don't need bytes left if new data
+                                        // block is shorter than the previous
+                                        // one. And better to trim them, e.g.
+                                        // this allows to avoid csum eroors
+                                        // when issuing overwrite
+                                        // (which happens to be partial)
+                                        // and original data is corrupted.
+                                        // Another side effect is that the
+                                        // superblock is not permanently
+                                        // anchored to a fixed disk location
+                                        // any more.
+    t.write(coll_t::meta(), oid, 0, bl.length(), bl);
     dout(20) << __func__ << " pg_num_history " << pg_num_history << dendl;
   }
 
@@ -8240,7 +8392,7 @@ void OSD::handle_osd_map(MOSDMap *m)
   }
 
   // superblock and commit
-  write_superblock(t);
+  write_superblock(cct, superblock, t);
   t.register_on_commit(new C_OnMapCommit(this, start, last, m));
   store->queue_transaction(
     service.meta_ch,
@@ -8558,7 +8710,7 @@ void OSD::check_osdmap_features()
       dout(0) << __func__ << " enabling on-disk ERASURE CODES compat feature" << dendl;
       superblock.compat_features.incompat.insert(CEPH_OSD_FEATURE_INCOMPAT_SHARDS);
       ObjectStore::Transaction t;
-      write_superblock(t);
+      write_superblock(cct, superblock, t);
       int err = store->queue_transaction(service.meta_ch, std::move(t), NULL);
       ceph_assert(err == 0);
     }
@@ -9888,7 +10040,7 @@ void OSD::maybe_override_max_osd_capacity_for_qos()
   // If the scheduler enabled is mclock, override the default
   // osd capacity with the value obtained from running the
   // osd bench test. This is later used to setup mclock.
-  if ((cct->_conf.get_val<std::string>("osd_op_queue") == "mclock_scheduler") &&
+  if ((op_queue_type_t::mClockScheduler == osd_op_queue_type()) &&
       (cct->_conf.get_val<bool>("osd_mclock_skip_benchmark") == false) &&
       (!unsupported_objstore_for_qos())) {
     std::string max_capacity_iops_config;
@@ -9988,7 +10140,7 @@ bool OSD::maybe_override_options_for_qos(const std::set<std::string> *changed)
 {
   // Override options only if the scheduler enabled is mclock and the
   // underlying objectstore is supported by mclock
-  if (cct->_conf.get_val<std::string>("osd_op_queue") == "mclock_scheduler" &&
+  if (op_queue_type_t::mClockScheduler == osd_op_queue_type() &&
       !unsupported_objstore_for_qos()) {
     static const std::map<std::string, uint64_t> recovery_qos_defaults {
       {"osd_recovery_max_active", 0},
@@ -10090,9 +10242,8 @@ void OSD::maybe_override_sleep_options_for_qos()
 {
   // Override options only if the scheduler enabled is mclock and the
   // underlying objectstore is supported by mclock
-  if (cct->_conf.get_val<std::string>("osd_op_queue") == "mclock_scheduler" &&
+  if (op_queue_type_t::mClockScheduler == osd_op_queue_type() &&
       !unsupported_objstore_for_qos()) {
-
     // Override the various sleep settings
     // Disable recovery sleep
     cct->_conf.set_val("osd_recovery_sleep", std::to_string(0));
@@ -10121,7 +10272,7 @@ void OSD::maybe_override_cost_for_qos()
 {
   // If the scheduler enabled is mclock, override the default PG deletion cost
   // so that mclock can meet the QoS goals.
-  if (cct->_conf.get_val<std::string>("osd_op_queue") == "mclock_scheduler" &&
+  if (op_queue_type_t::mClockScheduler == osd_op_queue_type() &&
       !unsupported_objstore_for_qos()) {
     uint64_t pg_delete_cost = 15728640;
     cct->_conf.set_val("osd_pg_delete_cost", std::to_string(pg_delete_cost));
@@ -10195,6 +10346,16 @@ bool OSD::unsupported_objstore_for_qos()
                    store->get_type()) != unsupported_objstores.end();
 }
 
+op_queue_type_t OSD::osd_op_queue_type() const
+{
+  /**
+   * All OSD shards employ the same scheduler type. Therefore, return
+   * the scheduler type set on the OSD shard with lowest id(0).
+   */
+  ceph_assert(shards.size());
+  return shards[0]->get_op_queue_type();
+}
+
 void OSD::update_log_config()
 {
   auto parsed_options = clog->parse_client_options(cct);
@@ -10695,17 +10856,17 @@ void OSDShard::update_scheduler_config()
   scheduler->update_configuration();
 }
 
-std::string OSDShard::get_scheduler_type()
+op_queue_type_t OSDShard::get_op_queue_type() const
 {
-  std::ostringstream scheduler_type;
-  scheduler_type << *scheduler;
-  return scheduler_type.str();
+  return scheduler->get_type();
 }
 
 OSDShard::OSDShard(
   int id,
   CephContext *cct,
-  OSD *osd)
+  OSD *osd,
+  op_queue_type_t osd_op_queue,
+  unsigned osd_op_queue_cut_off)
   : shard_id(id),
     cct(cct),
     osd(osd),
@@ -10717,7 +10878,7 @@ OSDShard::OSDShard(
     shard_lock{make_mutex(shard_lock_name)},
     scheduler(ceph::osd::scheduler::make_scheduler(
       cct, osd->whoami, osd->num_shards, id, osd->store->is_rotational(),
-      osd->store->get_type(), osd->monc)),
+      osd->store->get_type(), osd_op_queue, osd_op_queue_cut_off, osd->monc)),
     context_queue(sdata_wait_lock, sdata_cond)
 {
   dout(0) << "using op scheduler " << *scheduler << dendl;
diff --git a/src/osd/OSD.h b/src/osd/OSD.h
index 00fab7ec8..d25879001 100644
--- a/src/osd/OSD.h
+++ b/src/osd/OSD.h
@@ -511,7 +511,7 @@ public:
                               GenContext<ThreadPool::TPHandle&> *c,
                               uint64_t cost,
 			      int priority);
-  void queue_for_snap_trim(PG *pg);
+  void queue_for_snap_trim(PG *pg, uint64_t cost);
   void queue_for_scrub(PG* pg, Scrub::scrub_prio_t with_priority);
 
   void queue_scrub_after_repair(PG* pg, Scrub::scrub_prio_t with_priority);
@@ -1050,12 +1050,14 @@ struct OSDShard {
   void register_and_wake_split_child(PG *pg);
   void unprime_split_children(spg_t parent, unsigned old_pg_num);
   void update_scheduler_config();
-  std::string get_scheduler_type();
+  op_queue_type_t get_op_queue_type() const;
 
   OSDShard(
     int id,
     CephContext *cct,
-    OSD *osd);
+    OSD *osd,
+    op_queue_type_t osd_op_queue,
+    unsigned osd_op_queue_cut_off);
 };
 
 class OSD : public Dispatcher,
@@ -1235,8 +1237,9 @@ private:
   // -- superblock --
   OSDSuperblock superblock;
 
-  void write_superblock();
-  void write_superblock(ObjectStore::Transaction& t);
+  static void write_superblock(CephContext* cct,
+                               OSDSuperblock& sb,
+                               ObjectStore::Transaction& t);
   int read_superblock();
 
   void clear_temp_objects();
@@ -2055,6 +2058,9 @@ public:
   OSDService service;
   friend class OSDService;
 
+  /// op queue type set for the OSD
+  op_queue_type_t osd_op_queue_type() const;
+
 private:
   void set_perf_queries(const ConfigPayload &config_payload);
   MetricPayload get_perf_reports();
diff --git a/src/osd/OSDMap.cc b/src/osd/OSDMap.cc
index 11f9a87d7..5fb73084d 100644
--- a/src/osd/OSDMap.cc
+++ b/src/osd/OSDMap.cc
@@ -933,6 +933,10 @@ void OSDMap::Incremental::decode(ceph::buffer::list::const_iterator& bl)
       decode(new_last_up_change, bl);
       decode(new_last_in_change, bl);
     }
+    if (struct_v >= 9) {
+      decode(new_pg_upmap_primary, bl);
+      decode(old_pg_upmap_primary, bl);
+    }
     DECODE_FINISH(bl); // client-usable data
   }
 
@@ -1871,6 +1875,18 @@ uint64_t OSDMap::get_up_osd_features() const
   return cached_up_osd_features;
 }
 
+bool OSDMap::any_osd_laggy() const
+{
+  for (int osd = 0; osd < max_osd; ++osd) {
+    if (!is_up(osd)) { continue; }
+    const auto &xi = get_xinfo(osd);
+    if (xi.laggy_probability || xi.laggy_interval) {
+      return true;
+    }
+  }
+  return false;
+}
+
 void OSDMap::dedup(const OSDMap *o, OSDMap *n)
 {
   using ceph::encode;
diff --git a/src/osd/OSDMap.h b/src/osd/OSDMap.h
index 3a3e6155e..510da1116 100644
--- a/src/osd/OSDMap.h
+++ b/src/osd/OSDMap.h
@@ -655,6 +655,7 @@ private:
  public:
   bool have_crc() const { return crc_defined; }
   uint32_t get_crc() const { return crc; }
+  bool any_osd_laggy() const;
 
   std::shared_ptr<CrushWrapper> crush;       // hierarchical map
   bool stretch_mode_enabled; // we are in stretch mode, requiring multiple sites
diff --git a/src/osd/OpRequest.h b/src/osd/OpRequest.h
index 1a608b583..832c79353 100644
--- a/src/osd/OpRequest.h
+++ b/src/osd/OpRequest.h
@@ -35,6 +35,7 @@ public:
   bool op_info_needs_init() const { return op_info.get_flags() == 0; }
   bool check_rmw(int flag) const { return op_info.check_rmw(flag); }
   bool may_read() const { return op_info.may_read(); }
+  bool may_read_data() const { return op_info.may_read_data(); }
   bool may_write() const { return op_info.may_write(); }
   bool may_cache() const { return op_info.may_cache(); }
   bool rwordered_forced() const { return op_info.rwordered_forced(); }
diff --git a/src/osd/PG.cc b/src/osd/PG.cc
index fa49038ed..245aa8d00 100644
--- a/src/osd/PG.cc
+++ b/src/osd/PG.cc
@@ -420,15 +420,7 @@ void PG::queue_recovery()
     dout(10) << "queue_recovery -- queuing" << dendl;
     recovery_queued = true;
     // Let cost per object be the average object size
-    auto num_bytes = static_cast<uint64_t>(
-      std::max<int64_t>(
-	0, // ensure bytes is non-negative
-	info.stats.stats.sum.num_bytes));
-    auto num_objects = static_cast<uint64_t>(
-      std::max<int64_t>(
-	1, // ensure objects is non-negative and non-zero
-	info.stats.stats.sum.num_objects));
-    uint64_t cost_per_object = std::max<uint64_t>(num_bytes / num_objects, 1);
+    uint64_t cost_per_object = get_average_object_size();
     osd->queue_for_recovery(
       this, cost_per_object, recovery_state.get_recovery_op_priority()
     );
diff --git a/src/osd/PG.h b/src/osd/PG.h
index 88c893b35..2f8b59061 100644
--- a/src/osd/PG.h
+++ b/src/osd/PG.h
@@ -1019,6 +1019,19 @@ public:
     return num_bytes;
   }
 
+  uint64_t get_average_object_size() {
+    ceph_assert(ceph_mutex_is_locked_by_me(_lock));
+    auto num_bytes = static_cast<uint64_t>(
+      std::max<int64_t>(
+        0, // ensure bytes is non-negative
+        info.stats.stats.sum.num_bytes));
+    auto num_objects = static_cast<uint64_t>(
+      std::max<int64_t>(
+        1, // ensure objects is non-negative and non-zero
+        info.stats.stats.sum.num_objects));
+    return std::max<uint64_t>(num_bytes / num_objects, 1);
+  }
+
 protected:
 
   /*
diff --git a/src/osd/PrimaryLogPG.cc b/src/osd/PrimaryLogPG.cc
index 243e127eb..49178dc40 100644
--- a/src/osd/PrimaryLogPG.cc
+++ b/src/osd/PrimaryLogPG.cc
@@ -1667,7 +1667,11 @@ bool PrimaryLogPG::get_rw_locks(bool write_ordered, OpContext *ctx)
    * to get the second.
    */
   if (write_ordered && ctx->op->may_read()) {
-    ctx->lock_type = RWState::RWEXCL;
+    if (ctx->op->may_read_data()) {
+      ctx->lock_type = RWState::RWEXCL;
+    } else {
+      ctx->lock_type = RWState::RWWRITE;
+    }
   } else if (write_ordered) {
     ctx->lock_type = RWState::RWWRITE;
   } else {
@@ -5953,8 +5957,8 @@ int PrimaryLogPG::do_sparse_read(OpContext *ctx, OSDOp& osd_op) {
     encode(m, osd_op.outdata); // re-encode since it might be modified
     ::encode_destructively(data_bl, osd_op.outdata);
 
-    dout(10) << " sparse_read got " << r << " bytes from object "
-	     << soid << dendl;
+    dout(10) << " sparse_read got " << m.size() << " extents and " << r
+             << " bytes from object " << soid << dendl;
   }
 
   ctx->delta_stats.num_rd_kb += shift_round_up(op.extent.length, 10);
@@ -15627,8 +15631,10 @@ PrimaryLogPG::AwaitAsyncWork::AwaitAsyncWork(my_context ctx)
     NamedState(nullptr, "Trimming/AwaitAsyncWork")
 {
   auto *pg = context< SnapTrimmer >().pg;
+  // Determine cost in terms of the average object size
+  uint64_t cost_per_object = pg->get_average_object_size();
   context< SnapTrimmer >().log_enter(state_name);
-  context< SnapTrimmer >().pg->osd->queue_for_snap_trim(pg);
+  context< SnapTrimmer >().pg->osd->queue_for_snap_trim(pg, cost_per_object);
   pg->state_set(PG_STATE_SNAPTRIM);
   pg->state_clear(PG_STATE_SNAPTRIM_ERROR);
   pg->publish_stats_to_osd();
diff --git a/src/osd/osd_op_util.cc b/src/osd/osd_op_util.cc
index a33e2f110..d400a94db 100644
--- a/src/osd/osd_op_util.cc
+++ b/src/osd/osd_op_util.cc
@@ -16,6 +16,7 @@ bool OpInfo::check_rmw(int flag) const {
   ceph_assert(rmw_flags != 0);
   return rmw_flags & flag;
 }
+// Returns true if op performs a read (including of the object_info).
 bool OpInfo::may_read() const {
   return need_read_cap() || check_rmw(CEPH_OSD_RMW_FLAG_CLASS_READ);
 }
@@ -51,6 +52,16 @@ bool OpInfo::need_skip_promote() const {
 bool OpInfo::allows_returnvec() const {
   return check_rmw(CEPH_OSD_RMW_FLAG_RETURNVEC);
 }
+/**
+ * may_read_data()
+ * 
+ * Returns true if op reads information other than the object_info. Requires that the
+ * osd flush any prior writes prior to servicing this op. Includes any information not
+ * cached by the osd in the object_info or snapset.
+ */
+bool OpInfo::may_read_data() const {
+  return check_rmw(CEPH_OSD_RMW_FLAG_READ_DATA);
+}
 
 void OpInfo::set_rmw_flags(int flags) {
   rmw_flags |= flags;
@@ -67,6 +78,7 @@ void OpInfo::set_skip_handle_cache() { set_rmw_flags(CEPH_OSD_RMW_FLAG_SKIP_HAND
 void OpInfo::set_skip_promote() { set_rmw_flags(CEPH_OSD_RMW_FLAG_SKIP_PROMOTE); }
 void OpInfo::set_force_rwordered() { set_rmw_flags(CEPH_OSD_RMW_FLAG_RWORDERED); }
 void OpInfo::set_returnvec() { set_rmw_flags(CEPH_OSD_RMW_FLAG_RETURNVEC); }
+void OpInfo::set_read_data() { set_rmw_flags(CEPH_OSD_RMW_FLAG_READ_DATA); }
 
 
 int OpInfo::set_from_op(
@@ -108,8 +120,12 @@ int OpInfo::set_from_op(
       if (ceph_osd_op_mode_modify(iter->op.op))
 	set_write();
     }
-    if (ceph_osd_op_mode_read(iter->op.op))
+    if (ceph_osd_op_mode_read(iter->op.op)) {
       set_read();
+      if (iter->op.op != CEPH_OSD_OP_STAT) {
+        set_read_data();
+      }
+    }
 
     // set READ flag if there are src_oids
     if (iter->soid.oid.name.length())
@@ -202,6 +218,7 @@ int OpInfo::set_from_op(
       // watch state (and may return early if the watch exists) or, in
       // the case of ping, is simply a read op.
       set_read();
+      set_read_data();
       // fall through
     case CEPH_OSD_OP_NOTIFY:
     case CEPH_OSD_OP_NOTIFY_ACK:
diff --git a/src/osd/osd_op_util.h b/src/osd/osd_op_util.h
index 300fe40cc..fcd06c74b 100644
--- a/src/osd/osd_op_util.h
+++ b/src/osd/osd_op_util.h
@@ -47,6 +47,7 @@ public:
 
   bool check_rmw(int flag) const ;
   bool may_read() const;
+  bool may_read_data() const;
   bool may_write() const;
   bool may_cache() const;
   bool rwordered_forced() const;
@@ -70,6 +71,7 @@ public:
   void set_skip_promote();
   void set_force_rwordered();
   void set_returnvec();
+  void set_read_data();
 
   int set_from_op(
     const MOSDOp *m,
diff --git a/src/osd/osd_types.cc b/src/osd/osd_types.cc
index 14694de19..841a44b32 100644
--- a/src/osd/osd_types.cc
+++ b/src/osd/osd_types.cc
@@ -7371,3 +7371,31 @@ bool PGLSPlainFilter::filter(const hobject_t& obj,
 {
   return xattr_data.contents_equal(val.c_str(), val.size());
 }
+
+std::string_view get_op_queue_type_name(const op_queue_type_t &q)
+{
+  switch (q) {
+    case op_queue_type_t::WeightedPriorityQueue:
+      return "wpq";
+    case op_queue_type_t::mClockScheduler:
+      return "mclock_scheduler";
+    case op_queue_type_t::PrioritizedQueue:
+      return "PrioritizedQueue";
+    default:
+      return "unknown";
+  }
+}
+
+std::optional<op_queue_type_t> get_op_queue_type_by_name(
+  const std::string_view &s)
+{
+  if (s == "wpq") {
+    return op_queue_type_t::WeightedPriorityQueue;
+  } else if (s == "mclock_scheduler") {
+    return op_queue_type_t::mClockScheduler;
+  } else if (s == "PrioritizedQueue") {
+    return op_queue_type_t::PrioritizedQueue;
+  } else {
+    return std::nullopt;
+  }
+}
diff --git a/src/osd/osd_types.h b/src/osd/osd_types.h
index afed5fa83..5a50a32e7 100644
--- a/src/osd/osd_types.h
+++ b/src/osd/osd_types.h
@@ -367,12 +367,14 @@ enum {
   CEPH_OSD_RMW_FLAG_SKIP_PROMOTE      = (1 << 9),
   CEPH_OSD_RMW_FLAG_RWORDERED         = (1 << 10),
   CEPH_OSD_RMW_FLAG_RETURNVEC = (1 << 11),
+  CEPH_OSD_RMW_FLAG_READ_DATA  = (1 << 12),
 };
 
 
 // pg stuff
 
 #define OSD_SUPERBLOCK_GOBJECT ghobject_t(hobject_t(sobject_t(object_t("osd_superblock"), 0)))
+#define OSD_SUPERBLOCK_OMAP_KEY "osd_superblock"
 
 // placement seed (a hash value)
 typedef uint32_t ps_t;
@@ -6636,4 +6638,18 @@ using missing_map_t = std::map<hobject_t,
   std::pair<std::optional<uint32_t>,
     std::optional<uint32_t>>>;
 
+/**
+ * op_queue_type_t
+ *
+ * Supported op queue types
+ */
+enum class op_queue_type_t : uint8_t {
+  WeightedPriorityQueue = 0,
+  mClockScheduler,
+  PrioritizedQueue
+};
+std::string_view get_op_queue_type_name(const op_queue_type_t &q);
+std::optional<op_queue_type_t> get_op_queue_type_by_name(
+  const std::string_view &s);
+
 #endif
diff --git a/src/osd/scheduler/OpScheduler.cc b/src/osd/scheduler/OpScheduler.cc
index cb5ef13b6..12e5bdb6c 100644
--- a/src/osd/scheduler/OpScheduler.cc
+++ b/src/osd/scheduler/OpScheduler.cc
@@ -23,30 +23,25 @@ namespace ceph::osd::scheduler {
 
 OpSchedulerRef make_scheduler(
   CephContext *cct, int whoami, uint32_t num_shards, int shard_id,
-  bool is_rotational, std::string_view osd_objectstore, MonClient *monc)
+  bool is_rotational, std::string_view osd_objectstore,
+  op_queue_type_t osd_scheduler, unsigned op_queue_cut_off, MonClient *monc)
 {
-  const std::string *type = &cct->_conf->osd_op_queue;
-  if (*type == "debug_random") {
-    static const std::string index_lookup[] = { "mclock_scheduler",
-						"wpq" };
-    srand(time(NULL));
-    unsigned which = rand() % (sizeof(index_lookup) / sizeof(index_lookup[0]));
-    type = &index_lookup[which];
-  }
-
   // Force the use of 'wpq' scheduler for filestore OSDs.
   // The 'mclock_scheduler' is not supported for filestore OSDs.
-  if (*type == "wpq" || osd_objectstore == "filestore") {
+  if (op_queue_type_t::WeightedPriorityQueue == osd_scheduler ||
+      osd_objectstore == "filestore") {
     return std::make_unique<
       ClassedOpQueueScheduler<WeightedPriorityQueue<OpSchedulerItem, client>>>(
 	cct,
+        op_queue_cut_off,
 	cct->_conf->osd_op_pq_max_tokens_per_priority,
 	cct->_conf->osd_op_pq_min_cost
     );
-  } else if (*type == "mclock_scheduler") {
+  } else if (op_queue_type_t::mClockScheduler == osd_scheduler) {
     // default is 'mclock_scheduler'
     return std::make_unique<
-      mClockScheduler>(cct, whoami, num_shards, shard_id, is_rotational, monc);
+      mClockScheduler>(cct, whoami, num_shards, shard_id, is_rotational,
+        op_queue_cut_off, monc);
   } else {
     ceph_assert("Invalid choice of wq" == 0);
   }
diff --git a/src/osd/scheduler/OpScheduler.h b/src/osd/scheduler/OpScheduler.h
index 1575bcae4..570a2a162 100644
--- a/src/osd/scheduler/OpScheduler.h
+++ b/src/osd/scheduler/OpScheduler.h
@@ -18,6 +18,7 @@
 #include <variant>
 
 #include "common/ceph_context.h"
+#include "common/OpQueue.h"
 #include "mon/MonClient.h"
 #include "osd/scheduler/OpSchedulerItem.h"
 
@@ -54,6 +55,9 @@ public:
   // Apply config changes to the scheduler (if any)
   virtual void update_configuration() = 0;
 
+  // Get the scheduler type set for the queue
+  virtual op_queue_type_t get_type() const = 0;
+
   // Destructor
   virtual ~OpScheduler() {};
 };
@@ -63,7 +67,8 @@ using OpSchedulerRef = std::unique_ptr<OpScheduler>;
 
 OpSchedulerRef make_scheduler(
   CephContext *cct, int whoami, uint32_t num_shards, int shard_id,
-  bool is_rotational, std::string_view osd_objectstore, MonClient *monc);
+  bool is_rotational, std::string_view osd_objectstore,
+  op_queue_type_t osd_scheduler, unsigned op_queue_cut_off, MonClient *monc);
 
 /**
  * Implements OpScheduler in terms of OpQueue
@@ -78,21 +83,10 @@ class ClassedOpQueueScheduler final : public OpScheduler {
   unsigned cutoff;
   T queue;
 
-  static unsigned int get_io_prio_cut(CephContext *cct) {
-    if (cct->_conf->osd_op_queue_cut_off == "debug_random") {
-      srand(time(NULL));
-      return (rand() % 2 < 1) ? CEPH_MSG_PRIO_HIGH : CEPH_MSG_PRIO_LOW;
-    } else if (cct->_conf->osd_op_queue_cut_off == "high") {
-      return CEPH_MSG_PRIO_HIGH;
-    } else {
-      // default / catch-all is 'low'
-      return CEPH_MSG_PRIO_LOW;
-    }
-  }
 public:
   template <typename... Args>
-  ClassedOpQueueScheduler(CephContext *cct, Args&&... args) :
-    cutoff(get_io_prio_cut(cct)),
+  ClassedOpQueueScheduler(CephContext *cct, unsigned prio_cut, Args&&... args) :
+    cutoff(prio_cut),
     queue(std::forward<Args>(args)...)
   {}
 
@@ -143,6 +137,10 @@ public:
     // no-op
   }
 
+  op_queue_type_t get_type() const final {
+    return queue.get_type();
+  }
+
   ~ClassedOpQueueScheduler() final {};
 };
 
diff --git a/src/osd/scheduler/mClockScheduler.cc b/src/osd/scheduler/mClockScheduler.cc
index 0ea519655..f72683d52 100644
--- a/src/osd/scheduler/mClockScheduler.cc
+++ b/src/osd/scheduler/mClockScheduler.cc
@@ -35,12 +35,14 @@ mClockScheduler::mClockScheduler(CephContext *cct,
   uint32_t num_shards,
   int shard_id,
   bool is_rotational,
+  unsigned cutoff_priority,
   MonClient *monc)
   : cct(cct),
     whoami(whoami),
     num_shards(num_shards),
     shard_id(shard_id),
     is_rotational(is_rotational),
+    cutoff_priority(cutoff_priority),
     monc(monc),
     scheduler(
       std::bind(&mClockScheduler::ClientRegistry::get_info,
diff --git a/src/osd/scheduler/mClockScheduler.h b/src/osd/scheduler/mClockScheduler.h
index f708b1d7a..16e7f911f 100644
--- a/src/osd/scheduler/mClockScheduler.h
+++ b/src/osd/scheduler/mClockScheduler.h
@@ -27,7 +27,6 @@
 #include "osd/scheduler/OpScheduler.h"
 #include "common/config.h"
 #include "common/ceph_context.h"
-#include "common/mClockPriorityQueue.h"
 #include "osd/scheduler/OpSchedulerItem.h"
 
 
@@ -97,6 +96,7 @@ class mClockScheduler : public OpScheduler, md_config_obs_t {
   const uint32_t num_shards;
   const int shard_id;
   const bool is_rotational;
+  const unsigned cutoff_priority;
   MonClient *monc;
 
   /**
@@ -199,21 +199,6 @@ class mClockScheduler : public OpScheduler, md_config_obs_t {
     };
   }
 
-  static unsigned int get_io_prio_cut(CephContext *cct) {
-    if (cct->_conf->osd_op_queue_cut_off == "debug_random") {
-      std::random_device rd;
-      std::mt19937 random_gen(rd());
-      return (random_gen() % 2 < 1) ? CEPH_MSG_PRIO_HIGH : CEPH_MSG_PRIO_LOW;
-    } else if (cct->_conf->osd_op_queue_cut_off == "high") {
-      return CEPH_MSG_PRIO_HIGH;
-    } else {
-      // default / catch-all is 'low'
-      return CEPH_MSG_PRIO_LOW;
-    }
-  }
-
-  unsigned cutoff_priority = get_io_prio_cut(cct);
-
   /**
    * set_osd_capacity_params_from_config
    *
@@ -233,7 +218,8 @@ class mClockScheduler : public OpScheduler, md_config_obs_t {
 
 public: 
   mClockScheduler(CephContext *cct, int whoami, uint32_t num_shards,
-    int shard_id, bool is_rotational, MonClient *monc);
+    int shard_id, bool is_rotational, unsigned cutoff_priority,
+    MonClient *monc);
   ~mClockScheduler() override;
 
   /// Calculate scaled cost per item
@@ -260,12 +246,18 @@ public:
   void dump(ceph::Formatter &f) const final;
 
   void print(std::ostream &ostream) const final {
-    ostream << "mClockScheduler";
+    ostream << get_op_queue_type_name(get_type());
+    ostream << ", cutoff=" << cutoff_priority;
   }
 
   // Update data associated with the modified mclock config key(s)
   void update_configuration() final;
 
+  // Return the scheduler type
+  op_queue_type_t get_type() const final {
+    return op_queue_type_t::mClockScheduler;
+  }
+
   const char** get_tracked_conf_keys() const final;
   void handle_conf_change(const ConfigProxy& conf,
 			  const std::set<std::string> &changed) final;