crimson/os/seastore: move BtreeNodeMapping::is_viewable_by_trans to CachedExtent

Signed-off-by: Zhang Song <[email protected]>
(cherry picked from commit 54476e8)

Author: zhscn

src/crimson/os/seastore/btree/btree_range_pin.h

@@ -173,34 +173,9 @@ class BtreeNodeMapping : public PhysicalNodeMapping<key_t, val_t> {
     return parent->has_been_invalidated();
   }
 
-  bool is_unviewable_by_trans(CachedExtent& extent, Transaction &t) const {
-    if (!extent.is_valid()) {
-      return true;
-    }
-    if (extent.is_pending()) {
-      assert(extent.is_pending_in_trans(t.get_trans_id()));
-      return false;
-    }
-    auto &pendings = extent.mutation_pending_extents;
-    auto trans_id = t.get_trans_id();
-    bool unviewable = (pendings.find(trans_id, trans_spec_view_t::cmp_t()) !=
-		       pendings.end());
-    if (!unviewable) {
-      auto &trans = extent.retired_transactions;
-      unviewable = (trans.find(trans_id, trans_spec_view_t::cmp_t()) !=
-		 trans.end());
-      assert(unviewable ==
-             t.is_stable_extent_retired(extent.get_paddr(), extent.get_length()));
-    }
-    return unviewable;
-  }
-
   bool is_parent_viewable() const final {
     ceph_assert(parent);
-    if (!parent->is_valid()) {
-      return false;
-    }
-    return !is_unviewable_by_trans(*parent, ctx.trans);
+    return parent->is_viewable_by_trans(ctx.trans).first;
   }
   bool is_parent_valid() const final {
     ceph_assert(parent);

src/crimson/os/seastore/cached_extent.cc

@@ -110,6 +110,57 @@ void LogicalCachedExtent::maybe_set_intermediate_laddr(LBAMapping &mapping) {
     : mapping.get_key();
 }
 
+std::pair<bool, CachedExtent::viewable_state_t>
+CachedExtent::is_viewable_by_trans(Transaction &t) {
+  if (!is_valid()) {
+    return std::make_pair(false, viewable_state_t::invalid);
+  }
+
+  auto trans_id = t.get_trans_id();
+  if (is_pending()) {
+    ceph_assert(is_pending_in_trans(trans_id));
+    return std::make_pair(true, viewable_state_t::pending);
+  }
+
+  // shared by multiple transactions
+  assert(t.is_in_read_set(this));
+  assert(is_stable_written());
+
+  auto cmp = trans_spec_view_t::cmp_t();
+  if (mutation_pending_extents.find(trans_id, cmp) !=
+      mutation_pending_extents.end()) {
+    return std::make_pair(false, viewable_state_t::stable_become_pending);
+  }
+
+  if (retired_transactions.find(trans_id, cmp) !=
+      retired_transactions.end()) {
+    assert(t.is_stable_extent_retired(get_paddr(), get_length()));
+    return std::make_pair(false, viewable_state_t::stable_become_retired);
+  }
+
+  return std::make_pair(true, viewable_state_t::stable);
+}
+
+std::ostream &operator<<(
+  std::ostream &out,
+  CachedExtent::viewable_state_t state)
+{
+  switch(state) {
+  case CachedExtent::viewable_state_t::stable:
+    return out << "stable";
+  case CachedExtent::viewable_state_t::pending:
+    return out << "pending";
+  case CachedExtent::viewable_state_t::invalid:
+    return out << "invalid";
+  case CachedExtent::viewable_state_t::stable_become_retired:
+    return out << "stable_become_retired";
+  case CachedExtent::viewable_state_t::stable_become_pending:
+    return out << "stable_become_pending";
+  default:
+    __builtin_unreachable();
+  }
+}
+
 bool BufferSpace::is_range_loaded(extent_len_t offset, extent_len_t length) const
 {
   assert(length > 0);

src/crimson/os/seastore/cached_extent.h

@@ -789,6 +789,25 @@ class CachedExtent
     return is_pending() && pending_for_transaction == id;
   }
 
+  enum class viewable_state_t {
+    stable,                // viewable
+    pending,               // viewable
+    invalid,               // unviewable
+    stable_become_retired, // unviewable
+    stable_become_pending, // unviewable
+  };
+
+  /**
+   * is_viewable_by_trans
+   *
+   * Check if this extent is still viewable by transaction t.
+   *
+   * Precondition: *this was previously visible to t, which indicates
+   * this extent is either in the read set of t or created(pending) by t.
+   */
+  std::pair<bool, viewable_state_t>
+  is_viewable_by_trans(Transaction &t);
+
 private:
   template <typename T>
   friend class read_set_item_t;
@@ -1102,6 +1121,7 @@ class CachedExtent
 };
 
 std::ostream &operator<<(std::ostream &, CachedExtent::extent_state_t);
+std::ostream &operator<<(std::ostream &, CachedExtent::viewable_state_t);
 std::ostream &operator<<(std::ostream &, const CachedExtent&);
 
 /// Compare extents by paddr
@@ -1542,5 +1562,6 @@ using lextent_list_t = addr_extent_list_base_t<
 
 #if FMT_VERSION >= 90000
 template <> struct fmt::formatter<crimson::os::seastore::CachedExtent> : fmt::ostream_formatter {};
+template <> struct fmt::formatter<crimson::os::seastore::CachedExtent::viewable_state_t> : fmt::ostream_formatter {};
 template <> struct fmt::formatter<crimson::os::seastore::LogicalCachedExtent> : fmt::ostream_formatter {};
 #endif

src/crimson/os/seastore/transaction.h

@@ -166,6 +166,10 @@ class Transaction {
     return do_add_to_read_set(ref);
   }
 
+  bool is_in_read_set(CachedExtentRef extent) const {
+    return lookup_read_set(extent).first;
+  }
+
   void add_to_read_set(CachedExtentRef ref) {
     assert(ref->get_paddr().is_absolute()
            || ref->get_paddr().is_root());
@@ -594,7 +598,8 @@ class Transaction {
     }
   }
 
-  auto lookup_read_set(CachedExtentRef ref) const {
+  auto lookup_read_set(CachedExtentRef ref) const
+      -> std::pair<bool, read_trans_set_t<Transaction>::const_iterator> {
     assert(ref->is_valid());
     assert(!is_weak());
     auto it = ref->read_transactions.lower_bound(