diff --git a/payload_consumer/bzip_extent_writer.cc b/payload_consumer/bzip_extent_writer.cc
index 0c25c71..26fdc5f 100644
--- a/payload_consumer/bzip_extent_writer.cc
+++ b/payload_consumer/bzip_extent_writer.cc
@@ -29,8 +29,7 @@
   TEST_AND_RETURN(input_buffer_.empty());
 }
 
-bool BzipExtentWriter::Init(FileDescriptorPtr fd,
-                            const RepeatedPtrField<Extent>& extents,
+bool BzipExtentWriter::Init(const RepeatedPtrField<Extent>& extents,
                             uint32_t block_size) {
   // Init bzip2 stream
   int rc = BZ2_bzDecompressInit(&stream_,
@@ -39,7 +38,7 @@
 
   TEST_AND_RETURN_FALSE(rc == BZ_OK);
 
-  return next_->Init(fd, extents, block_size);
+  return next_->Init(extents, block_size);
 }
 
 bool BzipExtentWriter::Write(const void* bytes, size_t count) {
diff --git a/payload_consumer/bzip_extent_writer.h b/payload_consumer/bzip_extent_writer.h
index ec181a7..38c041a 100644
--- a/payload_consumer/bzip_extent_writer.h
+++ b/payload_consumer/bzip_extent_writer.h
@@ -40,8 +40,7 @@
   }
   ~BzipExtentWriter() override;
 
-  bool Init(FileDescriptorPtr fd,
-            const google::protobuf::RepeatedPtrField<Extent>& extents,
+  bool Init(const google::protobuf::RepeatedPtrField<Extent>& extents,
             uint32_t block_size) override;
   bool Write(const void* bytes, size_t count) override;
 
diff --git a/payload_consumer/bzip_extent_writer_unittest.cc b/payload_consumer/bzip_extent_writer_unittest.cc
index b587040..c93545a 100644
--- a/payload_consumer/bzip_extent_writer_unittest.cc
+++ b/payload_consumer/bzip_extent_writer_unittest.cc
@@ -29,7 +29,6 @@
 #include "update_engine/common/utils.h"
 #include "update_engine/payload_generator/extent_ranges.h"
 
-using google::protobuf::RepeatedPtrField;
 using std::min;
 using std::string;
 using std::vector;
@@ -64,9 +63,8 @@
       0x22, 0x9c, 0x28, 0x48, 0x66, 0x61, 0xb8, 0xea, 0x00,
   };
 
-  BzipExtentWriter bzip_writer(std::make_unique<DirectExtentWriter>());
-  EXPECT_TRUE(
-      bzip_writer.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
+  BzipExtentWriter bzip_writer(std::make_unique<DirectExtentWriter>(fd_));
+  EXPECT_TRUE(bzip_writer.Init({extents.begin(), extents.end()}, kBlockSize));
   EXPECT_TRUE(bzip_writer.Write(test, sizeof(test)));
 
   brillo::Blob buf;
@@ -97,9 +95,8 @@
 
   vector<Extent> extents = {ExtentForBytes(kBlockSize, 0, kDecompressedLength)};
 
-  BzipExtentWriter bzip_writer(std::make_unique<DirectExtentWriter>());
-  EXPECT_TRUE(
-      bzip_writer.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
+  BzipExtentWriter bzip_writer(std::make_unique<DirectExtentWriter>(fd_));
+  EXPECT_TRUE(bzip_writer.Init({extents.begin(), extents.end()}, kBlockSize));
 
   brillo::Blob original_compressed_data = compressed_data;
   for (brillo::Blob::size_type i = 0; i < compressed_data.size();
diff --git a/payload_consumer/extent_writer.h b/payload_consumer/extent_writer.h
index 9e53561..8b1b532 100644
--- a/payload_consumer/extent_writer.h
+++ b/payload_consumer/extent_writer.h
@@ -38,8 +38,7 @@
   virtual ~ExtentWriter() = default;
 
   // Returns true on success.
-  virtual bool Init(FileDescriptorPtr fd,
-                    const google::protobuf::RepeatedPtrField<Extent>& extents,
+  virtual bool Init(const google::protobuf::RepeatedPtrField<Extent>& extents,
                     uint32_t block_size) = 0;
 
   // Returns true on success.
@@ -51,13 +50,11 @@
 
 class DirectExtentWriter : public ExtentWriter {
  public:
-  DirectExtentWriter() = default;
+  explicit DirectExtentWriter(FileDescriptorPtr fd) : fd_(fd) {}
   ~DirectExtentWriter() override = default;
 
-  bool Init(FileDescriptorPtr fd,
-            const google::protobuf::RepeatedPtrField<Extent>& extents,
+  bool Init(const google::protobuf::RepeatedPtrField<Extent>& extents,
             uint32_t block_size) override {
-    fd_ = fd;
     block_size_ = block_size;
     extents_ = extents;
     cur_extent_ = extents_.begin();
diff --git a/payload_consumer/extent_writer_unittest.cc b/payload_consumer/extent_writer_unittest.cc
index afebb1a..5c67d3e 100644
--- a/payload_consumer/extent_writer_unittest.cc
+++ b/payload_consumer/extent_writer_unittest.cc
@@ -65,9 +65,8 @@
 TEST_F(ExtentWriterTest, SimpleTest) {
   vector<Extent> extents = {ExtentForRange(1, 1)};
   const string bytes = "1234";
-  DirectExtentWriter direct_writer;
-  EXPECT_TRUE(
-      direct_writer.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
+  DirectExtentWriter direct_writer{fd_};
+  EXPECT_TRUE(direct_writer.Init({extents.begin(), extents.end()}, kBlockSize));
   EXPECT_TRUE(direct_writer.Write(bytes.data(), bytes.size()));
 
   EXPECT_EQ(static_cast<off_t>(kBlockSize + bytes.size()),
@@ -84,9 +83,8 @@
 
 TEST_F(ExtentWriterTest, ZeroLengthTest) {
   vector<Extent> extents = {ExtentForRange(1, 1)};
-  DirectExtentWriter direct_writer;
-  EXPECT_TRUE(
-      direct_writer.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
+  DirectExtentWriter direct_writer{fd_};
+  EXPECT_TRUE(direct_writer.Init({extents.begin(), extents.end()}, kBlockSize));
   EXPECT_TRUE(direct_writer.Write(nullptr, 0));
 }
 
@@ -109,9 +107,8 @@
   brillo::Blob data(kBlockSize * 3);
   test_utils::FillWithData(&data);
 
-  DirectExtentWriter direct_writer;
-  EXPECT_TRUE(
-      direct_writer.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
+  DirectExtentWriter direct_writer{fd_};
+  EXPECT_TRUE(direct_writer.Init({extents.begin(), extents.end()}, kBlockSize));
 
   size_t bytes_written = 0;
   while (bytes_written < data.size()) {
@@ -150,9 +147,8 @@
   brillo::Blob data(17);
   test_utils::FillWithData(&data);
 
-  DirectExtentWriter direct_writer;
-  EXPECT_TRUE(
-      direct_writer.Init(fd_, {extents.begin(), extents.end()}, kBlockSize));
+  DirectExtentWriter direct_writer{fd_};
+  EXPECT_TRUE(direct_writer.Init({extents.begin(), extents.end()}, kBlockSize));
 
   size_t bytes_written = 0;
   while (bytes_written < (block_count * kBlockSize)) {
diff --git a/payload_consumer/fake_extent_writer.h b/payload_consumer/fake_extent_writer.h
index 7b2b7ac..680b1b3 100644
--- a/payload_consumer/fake_extent_writer.h
+++ b/payload_consumer/fake_extent_writer.h
@@ -33,8 +33,7 @@
   ~FakeExtentWriter() override = default;
 
   // ExtentWriter overrides.
-  bool Init(FileDescriptorPtr /* fd */,
-            const google::protobuf::RepeatedPtrField<Extent>& /* extents */,
+  bool Init(const google::protobuf::RepeatedPtrField<Extent>& /* extents */,
             uint32_t /* block_size */) override {
     init_called_ = true;
     return true;
diff --git a/payload_consumer/file_descriptor_utils.cc b/payload_consumer/file_descriptor_utils.cc
index 846cbd7..9a6a601 100644
--- a/payload_consumer/file_descriptor_utils.cc
+++ b/payload_consumer/file_descriptor_utils.cc
@@ -82,8 +82,8 @@
                         const RepeatedPtrField<Extent>& tgt_extents,
                         uint64_t block_size,
                         brillo::Blob* hash_out) {
-  DirectExtentWriter writer;
-  TEST_AND_RETURN_FALSE(writer.Init(target, tgt_extents, block_size));
+  DirectExtentWriter writer{target};
+  TEST_AND_RETURN_FALSE(writer.Init(tgt_extents, block_size));
   TEST_AND_RETURN_FALSE(utils::BlocksInExtents(src_extents) ==
                         utils::BlocksInExtents(tgt_extents));
   TEST_AND_RETURN_FALSE(
diff --git a/payload_consumer/partition_writer.cc b/payload_consumer/partition_writer.cc
index 6f06dd2..6f98ba3 100644
--- a/payload_consumer/partition_writer.cc
+++ b/payload_consumer/partition_writer.cc
@@ -326,8 +326,7 @@
     writer.reset(new XzExtentWriter(std::move(writer)));
   }
 
-  TEST_AND_RETURN_FALSE(
-      writer->Init(target_fd_, operation.dst_extents(), block_size_));
+  TEST_AND_RETURN_FALSE(writer->Init(operation.dst_extents(), block_size_));
   TEST_AND_RETURN_FALSE(writer->Write(data, operation.data_length()));
 
   return true;
@@ -377,7 +376,7 @@
   const auto& partition_control = dynamic_control_;
 
   InstallOperation buf;
-  bool should_optimize = partition_control->OptimizeOperation(
+  const bool should_optimize = partition_control->OptimizeOperation(
       partition.partition_name(), operation, &buf);
   const InstallOperation& optimized = should_optimize ? buf : operation;
 
@@ -493,8 +492,7 @@
       utils::BlocksInExtents(operation.src_extents()) * block_size_);
 
   auto writer = CreateBaseExtentWriter();
-  TEST_AND_RETURN_FALSE(
-      writer->Init(target_fd_, operation.dst_extents(), block_size_));
+  TEST_AND_RETURN_FALSE(writer->Init(operation.dst_extents(), block_size_));
   auto dst_file = std::make_unique<BsdiffExtentFile>(
       std::move(writer),
       utils::BlocksInExtents(operation.dst_extents()) * block_size_);
@@ -522,8 +520,7 @@
       utils::BlocksInExtents(operation.src_extents()) * block_size_));
 
   auto writer = CreateBaseExtentWriter();
-  TEST_AND_RETURN_FALSE(
-      writer->Init(target_fd_, operation.dst_extents(), block_size_));
+  TEST_AND_RETURN_FALSE(writer->Init(operation.dst_extents(), block_size_));
   puffin::UniqueStreamPtr dst_stream(new PuffinExtentStream(
       std::move(writer),
       utils::BlocksInExtents(operation.dst_extents()) * block_size_));
@@ -658,7 +655,7 @@
 }
 
 std::unique_ptr<ExtentWriter> PartitionWriter::CreateBaseExtentWriter() {
-  return std::make_unique<DirectExtentWriter>();
+  return std::make_unique<DirectExtentWriter>(target_fd_);
 }
 
 }  // namespace chromeos_update_engine
diff --git a/payload_consumer/partition_writer_unittest.cc b/payload_consumer/partition_writer_unittest.cc
index 91e5e26..263f338 100644
--- a/payload_consumer/partition_writer_unittest.cc
+++ b/payload_consumer/partition_writer_unittest.cc
@@ -82,10 +82,10 @@
   brillo::Blob PerformSourceCopyOp(const InstallOperation& op,
                                    const brillo::Blob blob_data) {
     ScopedTempFile source_partition("Blob-XXXXXX");
-    DirectExtentWriter extent_writer;
     FileDescriptorPtr fd(new EintrSafeFileDescriptor());
+    DirectExtentWriter extent_writer{fd};
     EXPECT_TRUE(fd->Open(source_partition.path().c_str(), O_RDWR));
-    EXPECT_TRUE(extent_writer.Init(fd, op.src_extents(), kBlockSize));
+    EXPECT_TRUE(extent_writer.Init(op.src_extents(), kBlockSize));
     EXPECT_TRUE(extent_writer.Write(blob_data.data(), blob_data.size()));
 
     ScopedTempFile target_partition("Blob-XXXXXX");
diff --git a/payload_consumer/snapshot_extent_writer.cc b/payload_consumer/snapshot_extent_writer.cc
index c9e6f31..242e726 100644
--- a/payload_consumer/snapshot_extent_writer.cc
+++ b/payload_consumer/snapshot_extent_writer.cc
@@ -36,7 +36,6 @@
 }
 
 bool SnapshotExtentWriter::Init(
-    FileDescriptorPtr /*fd*/,
     const google::protobuf::RepeatedPtrField<Extent>& extents,
     uint32_t block_size) {
   extents_ = extents;
diff --git a/payload_consumer/snapshot_extent_writer.h b/payload_consumer/snapshot_extent_writer.h
index 6d9fe7d..c3c64cd 100644
--- a/payload_consumer/snapshot_extent_writer.h
+++ b/payload_consumer/snapshot_extent_writer.h
@@ -29,8 +29,7 @@
   explicit SnapshotExtentWriter(android::snapshot::ICowWriter* cow_writer);
   ~SnapshotExtentWriter();
   // Returns true on success.
-  bool Init(FileDescriptorPtr fd,
-            const google::protobuf::RepeatedPtrField<Extent>& extents,
+  bool Init(const google::protobuf::RepeatedPtrField<Extent>& extents,
             uint32_t block_size) override;
   // Returns true on success.
   // This will construct a COW_REPLACE operation and forward it to CowWriter. It
diff --git a/payload_consumer/snapshot_extent_writer_unittest.cc b/payload_consumer/snapshot_extent_writer_unittest.cc
index 0e22482..2201043 100644
--- a/payload_consumer/snapshot_extent_writer_unittest.cc
+++ b/payload_consumer/snapshot_extent_writer_unittest.cc
@@ -107,7 +107,7 @@
 TEST_F(SnapshotExtentWriterTest, BufferWrites) {
   google::protobuf::RepeatedPtrField<Extent> extents;
   AddExtent(&extents, 123, 1);
-  writer_.Init(nullptr, extents, kBlockSize);
+  writer_.Init(extents, kBlockSize);
 
   std::vector<uint8_t> buf(kBlockSize, 0);
   buf[123] = 231;
@@ -130,7 +130,7 @@
   google::protobuf::RepeatedPtrField<Extent> extents;
   AddExtent(&extents, 123, 1);
   AddExtent(&extents, 125, 1);
-  writer_.Init(nullptr, extents, kBlockSize);
+  writer_.Init(extents, kBlockSize);
 
   std::vector<uint8_t> buf(kBlockSize * 2, 0);
   buf[123] = 231;
@@ -153,7 +153,7 @@
   google::protobuf::RepeatedPtrField<Extent> extents;
   AddExtent(&extents, 123, 1);
   AddExtent(&extents, 125, 2);
-  writer_.Init(nullptr, extents, kBlockSize);
+  writer_.Init(extents, kBlockSize);
 
   std::vector<uint8_t> buf(kBlockSize * 3);
   std::memset(buf.data(), 0, buf.size());
diff --git a/payload_consumer/xz_extent_writer.cc b/payload_consumer/xz_extent_writer.cc
index a5b939d..a648351 100644
--- a/payload_consumer/xz_extent_writer.cc
+++ b/payload_consumer/xz_extent_writer.cc
@@ -57,12 +57,11 @@
   TEST_AND_RETURN(input_buffer_.empty());
 }
 
-bool XzExtentWriter::Init(FileDescriptorPtr fd,
-                          const RepeatedPtrField<Extent>& extents,
+bool XzExtentWriter::Init(const RepeatedPtrField<Extent>& extents,
                           uint32_t block_size) {
   stream_ = xz_dec_init(XZ_DYNALLOC, kXzMaxDictSize);
   TEST_AND_RETURN_FALSE(stream_ != nullptr);
-  return underlying_writer_->Init(fd, extents, block_size);
+  return underlying_writer_->Init(extents, block_size);
 }
 
 bool XzExtentWriter::Write(const void* bytes, size_t count) {
diff --git a/payload_consumer/xz_extent_writer.h b/payload_consumer/xz_extent_writer.h
index e022274..70338f2 100644
--- a/payload_consumer/xz_extent_writer.h
+++ b/payload_consumer/xz_extent_writer.h
@@ -39,8 +39,7 @@
       : underlying_writer_(std::move(underlying_writer)) {}
   ~XzExtentWriter() override;
 
-  bool Init(FileDescriptorPtr fd,
-            const google::protobuf::RepeatedPtrField<Extent>& extents,
+  bool Init(const google::protobuf::RepeatedPtrField<Extent>& extents,
             uint32_t block_size) override;
   bool Write(const void* bytes, size_t count) override;
 
diff --git a/payload_consumer/xz_extent_writer_unittest.cc b/payload_consumer/xz_extent_writer_unittest.cc
index 34980a9..5269dbc 100644
--- a/payload_consumer/xz_extent_writer_unittest.cc
+++ b/payload_consumer/xz_extent_writer_unittest.cc
@@ -87,7 +87,7 @@
   }
 
   void WriteAll(const brillo::Blob& compressed) {
-    EXPECT_TRUE(xz_writer_->Init(fd_, {}, 1024));
+    EXPECT_TRUE(xz_writer_->Init({}, 1024));
     EXPECT_TRUE(xz_writer_->Write(compressed.data(), compressed.size()));
 
     EXPECT_TRUE(fake_extent_writer_->InitCalled());
@@ -130,7 +130,7 @@
 }
 
 TEST_F(XzExtentWriterTest, GarbageDataRejected) {
-  EXPECT_TRUE(xz_writer_->Init(fd_, {}, 1024));
+  EXPECT_TRUE(xz_writer_->Init({}, 1024));
   // The sample_data_ is an uncompressed string.
   EXPECT_FALSE(xz_writer_->Write(sample_data_.data(), sample_data_.size()));
 }
@@ -138,7 +138,7 @@
 TEST_F(XzExtentWriterTest, PartialDataIsKept) {
   brillo::Blob compressed(std::begin(kCompressed30KiBofA),
                           std::end(kCompressed30KiBofA));
-  EXPECT_TRUE(xz_writer_->Init(fd_, {}, 1024));
+  EXPECT_TRUE(xz_writer_->Init({}, 1024));
   for (uint8_t byte : compressed) {
     EXPECT_TRUE(xz_writer_->Write(&byte, 1));
   }