diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
index 755a3af..1ab6ada 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
@@ -183,7 +183,7 @@
     uint64_t num_total_data_ops_{};
     uint64_t num_ordered_ops_to_merge_{};
     bool has_seq_ops_{};
-    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc_;
+    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> xor_data_loc_;
     ReaderFlags reader_flag_;
     bool is_merge_{};
 };
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
index 93c31bb..296987a 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
@@ -82,7 +82,7 @@
     cow->merge_op_start_ = merge_op_start_;
     cow->num_total_data_ops_ = num_total_data_ops_;
     cow->num_ordered_ops_to_merge_ = num_ordered_ops_to_merge_;
-    cow->data_loc_ = data_loc_;
+    cow->xor_data_loc_ = xor_data_loc_;
     cow->block_pos_index_ = block_pos_index_;
     cow->is_merge_ = is_merge_;
     return cow;
@@ -139,7 +139,6 @@
             LOG(ERROR) << "Unknown version: " << header_.prefix.major_version;
             return false;
     }
-
     if (!parser->Parse(fd, header_, label)) {
         return false;
     }
@@ -154,7 +153,7 @@
     footer_ = parser->footer();
     fd_size_ = parser->fd_size();
     last_label_ = parser->last_label();
-    data_loc_ = parser->data_loc();
+    xor_data_loc_ = parser->xor_data_loc();
 
     // If we're resuming a write, we're not ready to merge
     if (label.has_value()) return true;
@@ -682,11 +681,10 @@
 
     uint64_t offset;
     if (op->type == kCowXorOp) {
-        offset = data_loc_->at(op->new_block);
+        offset = xor_data_loc_->at(op->new_block);
     } else {
         offset = GetCowOpSourceInfoData(*op);
     }
-
     if (!decompressor) {
         CowDataStream stream(this, offset + ignore_bytes, op->data_length - ignore_bytes);
         return stream.ReadFully(buffer, buffer_size);
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
index 76509de..993630b 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
@@ -82,7 +82,8 @@
     }
     for (const auto& op : *parser.get_v2ops()) {
         std::cout << op << "\n";
-        if (auto iter = parser.data_loc()->find(op.new_block); iter != parser.data_loc()->end()) {
+        if (auto iter = parser.xor_data_loc()->find(op.new_block);
+            iter != parser.xor_data_loc()->end()) {
             std::cout << "    data loc: " << iter->second << "\n";
         }
     }
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_base.h b/fs_mgr/libsnapshot/libsnapshot_cow/parser_base.h
index 2783407..837b33e 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/parser_base.h
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_base.h
@@ -38,7 +38,9 @@
                        std::optional<uint64_t> label = {}) = 0;
     virtual bool Translate(TranslatedCowOps* out) = 0;
     virtual std::optional<CowFooter> footer() const { return std::nullopt; }
-    virtual std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc() const = 0;
+    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> xor_data_loc() {
+        return xor_data_loc_;
+    };
 
     uint64_t fd_size() const { return fd_size_; }
     const std::optional<uint64_t>& last_label() const { return last_label_; }
@@ -47,6 +49,7 @@
     CowHeaderV3 header_ = {};
     uint64_t fd_size_;
     std::optional<uint64_t> last_label_;
+    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> xor_data_loc_ = {};
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp
index 51489c8..08a43a4 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp
@@ -63,7 +63,7 @@
 
 bool CowParserV2::ParseOps(borrowed_fd fd, std::optional<uint64_t> label) {
     uint64_t pos;
-    auto data_loc = std::make_shared<std::unordered_map<uint64_t, uint64_t>>();
+    auto xor_data_loc = std::make_shared<std::unordered_map<uint64_t, uint64_t>>();
 
     // Skip the scratch space
     if (header_.prefix.major_version >= 2 && (header_.buffer_size > 0)) {
@@ -111,7 +111,7 @@
             auto& current_op = ops_buffer->data()[current_op_num];
             current_op_num++;
             if (current_op.type == kCowXorOp) {
-                data_loc->insert({current_op.new_block, data_pos});
+                xor_data_loc->insert({current_op.new_block, data_pos});
             }
             pos += sizeof(CowOperationV2) + GetNextOpOffset(current_op, header_.cluster_ops);
             data_pos += current_op.data_length + GetNextDataOffset(current_op, header_.cluster_ops);
@@ -193,7 +193,7 @@
 
     v2_ops_ = ops_buffer;
     v2_ops_->shrink_to_fit();
-    data_loc_ = data_loc;
+    xor_data_loc_ = xor_data_loc;
     return true;
 }
 
@@ -239,9 +239,5 @@
     return true;
 }
 
-std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> CowParserV2::data_loc() const {
-    return data_loc_;
-}
-
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h
index 318a3ac..f9ee2e5 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h
@@ -35,10 +35,8 @@
 
     const CowHeader& header() const { return header_; }
     std::shared_ptr<std::vector<CowOperationV2>> get_v2ops() { return v2_ops_; }
-    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc() const override;
 
   private:
-    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc_;
     bool ParseOps(android::base::borrowed_fd fd, std::optional<uint64_t> label);
     std::shared_ptr<std::vector<CowOperationV2>> v2_ops_;
     std::optional<CowFooter> footer_;
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp
index 23ddaae..a8a63d8 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp
@@ -58,6 +58,10 @@
     return ParseOps(fd, label);
 }
 
+off_t CowParserV3::GetDataOffset() const {
+    return sizeof(CowHeaderV3) + header_.buffer_size + header_.op_count_max * sizeof(CowOperation);
+}
+
 bool CowParserV3::ParseOps(borrowed_fd fd, std::optional<uint64_t> label) {
     ops_ = std::make_shared<std::vector<CowOperationV3>>();
     ops_->resize(header_.op_count);
@@ -69,12 +73,24 @@
         return false;
     }
 
+    // fill out mapping of XOR op data location
+    uint64_t data_pos = GetDataOffset();
+
+    xor_data_loc_ = std::make_shared<std::unordered_map<uint64_t, uint64_t>>();
+
+    for (auto op : *ops_) {
+        if (op.type == kCowXorOp) {
+            xor_data_loc_->insert({op.new_block, data_pos});
+        }
+        data_pos += op.data_length;
+    }
     // :TODO: sequence buffer & resume buffer follow
     // Once we implement labels, we'll have to discard unused ops and adjust
     // the header as needed.
     CHECK(!label);
 
     ops_->shrink_to_fit();
+
     return true;
 }
 
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h
index 5760cf2..e2663cc 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h
@@ -45,13 +45,10 @@
     bool Parse(android::base::borrowed_fd fd, const CowHeaderV3& header,
                std::optional<uint64_t> label = {}) override;
     bool Translate(TranslatedCowOps* out) override;
-    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc() const override {
-        return nullptr;
-    };
 
   private:
     bool ParseOps(android::base::borrowed_fd fd, std::optional<uint64_t> label);
-
+    off_t GetDataOffset() const;
     CowHeaderV3 header_ = {};
     std::shared_ptr<std::vector<CowOperationV3>> ops_;
 };
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp
index c5d7a02..3277c99 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp
@@ -218,7 +218,7 @@
     CowReader reader;
     ASSERT_TRUE(reader.Parse(cow_->fd));
 
-    const auto& header = reader.GetHeader();
+    const auto& header = reader.header_v3();
     ASSERT_EQ(header.prefix.magic, kCowMagicNumber);
     ASSERT_EQ(header.prefix.major_version, 3);
     ASSERT_EQ(header.prefix.minor_version, kCowVersionMinor);
@@ -242,5 +242,84 @@
     ASSERT_EQ(i, 100);
 }
 
+TEST_F(CowTestV3, XorOp) {
+    CowOptions options;
+    options.op_count_max = 100;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+
+    std::string data = "This is test data-1. Testing xor";
+    data.resize(options.block_size, '\0');
+    ASSERT_TRUE(writer->AddXorBlocks(50, data.data(), data.size(), 24, 10));
+    ASSERT_TRUE(writer->Finalize());
+
+    ASSERT_EQ(lseek(cow_->fd, 0, SEEK_SET), 0);
+
+    CowReader reader;
+
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    const auto& header = reader.header_v3();
+    ASSERT_EQ(header.op_count, 1);
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+    ASSERT_FALSE(iter->AtEnd());
+    auto op = iter->Get();
+    std::string sink(data.size(), '\0');
+
+    ASSERT_EQ(op->type, kCowXorOp);
+    ASSERT_EQ(op->data_length, 4096);
+    ASSERT_EQ(op->new_block, 50);
+    ASSERT_EQ(GetCowOpSourceInfoData(*op), 98314);  // 4096 * 24 + 10
+    ASSERT_TRUE(ReadData(reader, op, sink.data(), sink.size()));
+    ASSERT_EQ(sink, data);
+}
+
+TEST_F(CowTestV3, ConsecutiveXorOp) {
+    CowOptions options;
+    options.op_count_max = 100;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+
+    std::string data;
+    data.resize(options.block_size * 5);
+    for (int i = 0; i < data.size(); i++) {
+        data[i] = char(rand() % 256);
+    }
+
+    ASSERT_TRUE(writer->AddXorBlocks(50, data.data(), data.size(), 24, 10));
+    ASSERT_TRUE(writer->Finalize());
+
+    ASSERT_EQ(lseek(cow_->fd, 0, SEEK_SET), 0);
+
+    CowReader reader;
+
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    const auto& header = reader.header_v3();
+    ASSERT_EQ(header.op_count, 5);
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+    ASSERT_FALSE(iter->AtEnd());
+
+    std::string sink(data.size(), '\0');
+    size_t i = 0;
+
+    while (!iter->AtEnd()) {
+        auto op = iter->Get();
+        ASSERT_EQ(op->type, kCowXorOp);
+        ASSERT_EQ(op->data_length, 4096);
+        ASSERT_EQ(op->new_block, 50 + i);
+        ASSERT_EQ(GetCowOpSourceInfoData(*op), 98314 + (i * options.block_size));  // 4096 * 24 + 10
+        ASSERT_TRUE(
+                ReadData(reader, op, sink.data() + (i * options.block_size), options.block_size));
+        iter->Next();
+        i++;
+    }
+    ASSERT_EQ(sink, data);
+
+    ASSERT_EQ(i, 5);
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp
index aeb088d..13b6157 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp
@@ -163,7 +163,6 @@
     }
     next_data_pos_ =
             sizeof(CowHeaderV3) + header_.buffer_size + header_.op_count_max * sizeof(CowOperation);
-
     return true;
 }
 
@@ -187,19 +186,12 @@
 
 bool CowWriterV3::EmitXorBlocks(uint32_t new_block_start, const void* data, size_t size,
                                 uint32_t old_block, uint16_t offset) {
-    LOG(ERROR) << __LINE__ << " " << __FILE__ << " <- function here should never be called";
-    if (new_block_start || old_block || offset || data || size) return false;
-    return false;
+    return EmitBlocks(new_block_start, data, size, old_block, offset, kCowXorOp);
 }
 
 bool CowWriterV3::EmitBlocks(uint64_t new_block_start, const void* data, size_t size,
                              uint64_t old_block, uint16_t offset, uint8_t type) {
     const uint8_t* iter = reinterpret_cast<const uint8_t*>(data);
-
-    // Placing here until we support XOR ops
-    CHECK_EQ(old_block, 0);
-    CHECK_EQ(offset, 0);
-
     const size_t num_blocks = (size / header_.block_size);
 
     for (size_t i = 0; i < num_blocks; i++) {
@@ -207,12 +199,18 @@
         op.new_block = new_block_start + i;
 
         op.type = type;
-        op.source_info = next_data_pos_;
         op.data_length = static_cast<uint16_t>(header_.block_size);
+
+        if (type == kCowXorOp) {
+            op.source_info = (old_block + i) * header_.block_size + offset;
+        } else {
+            op.source_info = next_data_pos_;
+        }
         if (!WriteOperation(op, iter, header_.block_size)) {
             LOG(ERROR) << "AddRawBlocks: write failed";
             return false;
         }
+
         iter += header_.block_size;
     }