crimson/os/seastore/object_data_handler: prevent from being overwritten if cloned

Signed-off-by: Myoungwon Oh <[email protected]>

Author: myoungwon

src/crimson/os/seastore/backref/btree_backref_manager.h

@@ -35,6 +35,10 @@ class BtreeBackrefMapping : public BtreeNodeMapping<paddr_t, laddr_t> {
     return type;
   }
 
+  bool is_clone() const final {
+    return false;
+  }
+
 protected:
   std::unique_ptr<BtreeNodeMapping<paddr_t, laddr_t>> _duplicate(
     op_context_t<paddr_t> ctx) const final {

src/crimson/os/seastore/cached_extent.h

@@ -1054,6 +1054,7 @@ class PhysicalNodeMapping {
   }
 
   virtual bool is_stable() const = 0;
+  virtual bool is_clone() const = 0;
   bool is_zero_reserved() const {
     return !get_val().is_real();
   }

src/crimson/os/seastore/lba_manager/btree/btree_lba_manager.h

@@ -137,6 +137,10 @@ class BtreeLBAMapping : public BtreeNodeMapping<laddr_t, paddr_t> {
     return intermediate_length;
   }
 
+  bool is_clone() const final {
+    return get_map_val().refcount > 1;
+  }
+
 protected:
   std::unique_ptr<BtreeNodeMapping<laddr_t, paddr_t>> _duplicate(
     op_context_t<laddr_t> ctx) const final {

src/crimson/os/seastore/object_data_handler.cc

@@ -323,7 +323,7 @@ overwrite_ops_t prepare_ops_list(
 	  [&region, &to_remap](auto &r) {
 	    interval_set<uint64_t> range;
 	    range.insert(r->get_key(), r->get_length());
-	    if (range.contains(region.addr, region.len)) {
+	    if (range.contains(region.addr, region.len) && !r->is_clone()) {
 	      to_remap.push_back(extent_to_remap_t::create_overwrite(
 		0, region.len, std::move(r), *region.to_write));
 	      return true;
@@ -339,7 +339,7 @@ overwrite_ops_t prepare_ops_list(
 	  [&region, &to_remap](auto &r) {
 	    interval_set<uint64_t> range;
 	    range.insert(r.pin->get_key(), r.pin->get_length());
-	    if (range.contains(region.addr, region.len)) {
+	    if (range.contains(region.addr, region.len) && !r.pin->is_clone()) {
 	      to_remap.push_back(extent_to_remap_t::create_overwrite(
 		region.addr - range.begin().get_start(), region.len,
 		std::move(r.pin), *region.to_write));

src/crimson/os/seastore/transaction_manager.h

@@ -320,7 +320,7 @@ class TransactionManager : public ExtentCallbackInterface {
   read_extent_ret<T> get_mutable_extent_by_laddr(Transaction &t, laddr_t laddr, extent_len_t len) {
     return get_pin(t, laddr
     ).si_then([this, &t, len](auto pin) {
-      ceph_assert(pin->is_stable());
+      ceph_assert(pin->is_stable() && !pin->is_zero_reserved());
       ceph_assert(!pin->is_clone());
       ceph_assert(pin->get_length() == len);
       return this->read_pin<T>(t, std::move(pin));