crimson/os/seastore/onode: add the "need_cow" field to indicate whether

the onode's object data space needs to do clone before modification

At present, it's only when the onode's object data space is sharing its
own direct lba mappings with other onodes that the "need_cow" field
would be true.

Signed-off-by: Xuehan Xu <[email protected]>

Author: xxhdx1985126

src/crimson/os/seastore/onode.h

@@ -40,6 +40,14 @@ struct onode_layout_t {
 
   char oi[MAX_OI_LENGTH] = {0};
   char ss[MAX_SS_LENGTH] = {0};
+  /**
+    * needs_cow
+    *
+    * If true, all lba mappings for onode must be cloned
+    * to a new range prior to mutation. See ObjectDataHandler::copy_on_write,
+    * do_clone, do_clonerange
+    */
+  bool need_cow = false;
 
   onode_layout_t() : omap_root(omap_type_t::OMAP), log_root(omap_type_t::LOG),
     xattr_root(omap_type_t::XATTR) {}
@@ -94,6 +102,8 @@ class Onode : public boost::intrusive_ref_counter<
   virtual void update_snapset(Transaction&, ceph::bufferlist&) = 0;
   virtual void clear_object_info(Transaction&) = 0;
   virtual void clear_snapset(Transaction&) = 0;
+  virtual void set_need_cow(Transaction&) = 0;
+  virtual void unset_need_cow(Transaction&) = 0;
 
   laddr_t get_metadata_hint(uint64_t block_size) const {
     assert(default_metadata_offset);

src/crimson/os/seastore/onode_manager/staged-fltree/fltree_onode_manager.cc

@@ -20,6 +20,18 @@ void FLTreeOnode::Recorder::apply_value_delta(
     ceph::decode(op, bliter);
     auto &mlayout = *reinterpret_cast<onode_layout_t*>(value.get_write());
     switch (op) {
+    case delta_op_t::UNSET_NEED_COW:
+      DEBUG("setting need_cow");
+      bliter.copy(
+	sizeof(mlayout.need_cow),
+	(char *)&mlayout.need_cow);
+      break;
+    case delta_op_t::SET_NEED_COW:
+      DEBUG("setting need_cow");
+      bliter.copy(
+	sizeof(mlayout.need_cow),
+	(char *)&mlayout.need_cow);
+      break;
     case delta_op_t::UPDATE_ONODE_SIZE:
       DEBUG("update onode size");
       bliter.copy(sizeof(mlayout.size), (char *)&mlayout.size);
@@ -80,6 +92,18 @@ void FLTreeOnode::Recorder::encode_update(
   auto &encoded = get_encoded(payload_mut);
   ceph::encode(op, encoded);
   switch(op) {
+  case delta_op_t::UNSET_NEED_COW:
+    DEBUG("setting need_cow");
+    encoded.append(
+      (const char *)&layout.need_cow,
+      sizeof(layout.need_cow));
+    break;
+  case delta_op_t::SET_NEED_COW:
+    DEBUG("setting need_cow");
+    encoded.append(
+      (const char *)&layout.need_cow,
+      sizeof(layout.need_cow));
+    break;
   case delta_op_t::UPDATE_ONODE_SIZE:
     DEBUG("update onode size");
     encoded.append(

src/crimson/os/seastore/onode_manager/staged-fltree/fltree_onode_manager.h

@@ -56,7 +56,9 @@ struct FLTreeOnode final : Onode, Value {
       UPDATE_SNAPSET,
       CLEAR_OBJECT_INFO,
       CLEAR_SNAPSET,
-      CREATE_DEFAULT
+      CREATE_DEFAULT,
+      SET_NEED_COW,
+      UNSET_NEED_COW
     };
     Recorder(bufferlist &bl) : ValueDeltaRecorder(bl) {}
 
@@ -105,6 +107,34 @@ struct FLTreeOnode final : Onode, Value {
     });
   }
 
+  void set_need_cow(Transaction &t) final {
+    with_mutable_layout(
+      t,
+      [](NodeExtentMutable &payload_mut, Recorder *recorder) {
+	auto &mlayout = *reinterpret_cast<onode_layout_t*>(
+          payload_mut.get_write());
+	mlayout.need_cow = true;
+	if (recorder) {
+	  recorder->encode_update(
+	    payload_mut, Recorder::delta_op_t::SET_NEED_COW);
+	}
+    });
+  }
+
+  void unset_need_cow(Transaction &t) final {
+    with_mutable_layout(
+      t,
+      [](NodeExtentMutable &payload_mut, Recorder *recorder) {
+	auto &mlayout = *reinterpret_cast<onode_layout_t*>(
+          payload_mut.get_write());
+	mlayout.need_cow = false;
+	if (recorder) {
+	  recorder->encode_update(
+	    payload_mut, Recorder::delta_op_t::UNSET_NEED_COW);
+	}
+    });
+  }
+
   void update_onode_size(Transaction &t, uint32_t size) final {
     with_mutable_layout(
       t,

src/test/crimson/seastore/test_object_data_handler.cc

@@ -39,6 +39,18 @@ class TestOnode final : public Onode {
   laddr_t get_hint() const final {return L_ADDR_MIN; }
   ~TestOnode() final = default;
 
+  void set_need_cow(Transaction &t) final {
+    with_mutable_layout(t, [](onode_layout_t &mlayout) {
+      mlayout.need_cow = true;
+    });
+  }
+
+  void unset_need_cow(Transaction &t) final {
+    with_mutable_layout(t, [](onode_layout_t &mlayout) {
+      mlayout.need_cow = false;
+    });
+  }
+
   void update_onode_size(Transaction &t, uint32_t size) final {
     with_mutable_layout(t, [size](onode_layout_t &mlayout) {
       mlayout.size = size;