diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
index 8e61a21..0450d7f 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
@@ -29,35 +29,6 @@
 
 class ICowOpIter;
 
-// A ByteSink object handles requests for a buffer of a specific size. It
-// always owns the underlying buffer. It's designed to minimize potential
-// copying as we parse or decompress the COW.
-class IByteSink {
-  public:
-    virtual ~IByteSink() {}
-
-    // Called when the reader has data. The size of the request is given. The
-    // sink must return a valid pointer (or null on failure), and return the
-    // maximum number of bytes that can be written to the returned buffer.
-    //
-    // The returned buffer is owned by IByteSink, but must remain valid until
-    // the read operation has completed (or the entire buffer has been
-    // covered by calls to ReturnData).
-    //
-    // After calling GetBuffer(), all previous buffers returned are no longer
-    // valid.
-    //
-    // GetBuffer() is intended to be sequential. A returned size of N indicates
-    // that the output stream will advance by N bytes, and the ReturnData call
-    // indicates that those bytes have been fulfilled. Therefore, it is
-    // possible to have ReturnBuffer do nothing, if the implementation doesn't
-    // care about incremental writes.
-    virtual void* GetBuffer(size_t requested, size_t* actual) = 0;
-
-    // Called when a section returned by |GetBuffer| has been filled with data.
-    virtual bool ReturnData(void* buffer, size_t length) = 0;
-};
-
 // Interface for reading from a snapuserd COW.
 class ICowReader {
   public:
@@ -84,10 +55,6 @@
     virtual std::unique_ptr<ICowOpIter> GetMergeOpIter(bool ignore_progress) = 0;
 
     // Get decoded bytes from the data section, handling any decompression.
-    // All retrieved data is passed to the sink.
-    virtual bool ReadData(const CowOperation& op, IByteSink* sink) = 0;
-
-    // Get decoded bytes from the data section, handling any decompression.
     //
     // If ignore_bytes is non-zero, it specifies the initial number of bytes
     // to skip writing to |buffer|.
@@ -153,7 +120,6 @@
     std::unique_ptr<ICowOpIter> GetRevMergeOpIter(bool ignore_progress = false) override;
     std::unique_ptr<ICowOpIter> GetMergeOpIter(bool ignore_progress = false) override;
 
-    bool ReadData(const CowOperation& op, IByteSink* sink) override;
     ssize_t ReadData(const CowOperation& op, void* buffer, size_t buffer_size,
                      size_t ignore_bytes = 0) override;
 
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.cpp
index 483d559..3d34413 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.cpp
@@ -64,69 +64,17 @@
     }
 }
 
-class NoDecompressor final : public IDecompressor {
-  public:
-    bool Decompress(size_t) override;
-    ssize_t Decompress(void*, size_t, size_t, size_t) override {
-        LOG(ERROR) << "Not supported";
-        return -1;
-    }
-};
-
-bool NoDecompressor::Decompress(size_t) {
-    size_t stream_remaining = stream_->Size();
-    while (stream_remaining) {
-        size_t buffer_size = stream_remaining;
-        uint8_t* buffer = reinterpret_cast<uint8_t*>(sink_->GetBuffer(buffer_size, &buffer_size));
-        if (!buffer) {
-            LOG(ERROR) << "Could not acquire buffer from sink";
-            return false;
-        }
-
-        // Read until we can fill the buffer.
-        uint8_t* buffer_pos = buffer;
-        size_t bytes_to_read = std::min(buffer_size, stream_remaining);
-        while (bytes_to_read) {
-            ssize_t read = stream_->Read(buffer_pos, bytes_to_read);
-            if (read < 0) {
-                return false;
-            }
-            if (!read) {
-                LOG(ERROR) << "Stream ended prematurely";
-                return false;
-            }
-            if (!sink_->ReturnData(buffer_pos, read)) {
-                LOG(ERROR) << "Could not return buffer to sink";
-                return false;
-            }
-            buffer_pos += read;
-            bytes_to_read -= read;
-            stream_remaining -= read;
-        }
-    }
-    return true;
-}
-
-std::unique_ptr<IDecompressor> IDecompressor::Uncompressed() {
-    return std::unique_ptr<IDecompressor>(new NoDecompressor());
-}
-
 // Read chunks of the COW and incrementally stream them to the decoder.
 class StreamDecompressor : public IDecompressor {
   public:
-    bool Decompress(size_t output_bytes) override;
     ssize_t Decompress(void* buffer, size_t buffer_size, size_t decompressed_size,
                        size_t ignore_bytes) override;
 
     virtual bool Init() = 0;
-    virtual bool DecompressInput(const uint8_t* data, size_t length) = 0;
     virtual bool PartialDecompress(const uint8_t* data, size_t length) = 0;
     bool OutputFull() const { return !ignore_bytes_ && !output_buffer_remaining_; }
 
   protected:
-    bool GetFreshBuffer();
-
-    size_t output_bytes_;
     size_t stream_remaining_;
     uint8_t* output_buffer_ = nullptr;
     size_t output_buffer_remaining_ = 0;
@@ -136,43 +84,6 @@
 
 static constexpr size_t kChunkSize = 4096;
 
-bool StreamDecompressor::Decompress(size_t output_bytes) {
-    if (!Init()) {
-        return false;
-    }
-
-    stream_remaining_ = stream_->Size();
-    output_bytes_ = output_bytes;
-
-    uint8_t chunk[kChunkSize];
-    while (stream_remaining_) {
-        size_t max_read = std::min(stream_remaining_, sizeof(chunk));
-        ssize_t read = stream_->Read(chunk, max_read);
-        if (read < 0) {
-            return false;
-        }
-        if (!read) {
-            LOG(ERROR) << "Stream ended prematurely";
-            return false;
-        }
-        if (!DecompressInput(chunk, read)) {
-            return false;
-        }
-
-        stream_remaining_ -= read;
-
-        if (stream_remaining_ && decompressor_ended_) {
-            LOG(ERROR) << "Decompressor terminated early";
-            return false;
-        }
-    }
-    if (!decompressor_ended_) {
-        LOG(ERROR) << "Decompressor expected more bytes";
-        return false;
-    }
-    return true;
-}
-
 ssize_t StreamDecompressor::Decompress(void* buffer, size_t buffer_size, size_t,
                                        size_t ignore_bytes) {
     if (!Init()) {
@@ -220,23 +131,11 @@
     return buffer_size - output_buffer_remaining_;
 }
 
-bool StreamDecompressor::GetFreshBuffer() {
-    size_t request_size = std::min(output_bytes_, kChunkSize);
-    output_buffer_ =
-            reinterpret_cast<uint8_t*>(sink_->GetBuffer(request_size, &output_buffer_remaining_));
-    if (!output_buffer_) {
-        LOG(ERROR) << "Could not acquire buffer from sink";
-        return false;
-    }
-    return true;
-}
-
 class GzDecompressor final : public StreamDecompressor {
   public:
     ~GzDecompressor();
 
     bool Init() override;
-    bool DecompressInput(const uint8_t* data, size_t length) override;
     bool PartialDecompress(const uint8_t* data, size_t length) override;
 
   private:
@@ -255,50 +154,6 @@
     inflateEnd(&z_);
 }
 
-bool GzDecompressor::DecompressInput(const uint8_t* data, size_t length) {
-    z_.next_in = reinterpret_cast<Bytef*>(const_cast<uint8_t*>(data));
-    z_.avail_in = length;
-
-    while (z_.avail_in) {
-        // If no more output buffer, grab a new buffer.
-        if (z_.avail_out == 0) {
-            if (!GetFreshBuffer()) {
-                return false;
-            }
-            z_.next_out = reinterpret_cast<Bytef*>(output_buffer_);
-            z_.avail_out = output_buffer_remaining_;
-        }
-
-        // Remember the position of the output buffer so we can call ReturnData.
-        auto avail_out = z_.avail_out;
-
-        // Decompress.
-        int rv = inflate(&z_, Z_NO_FLUSH);
-        if (rv != Z_OK && rv != Z_STREAM_END) {
-            LOG(ERROR) << "inflate returned error code " << rv;
-            return false;
-        }
-
-        size_t returned = avail_out - z_.avail_out;
-        if (!sink_->ReturnData(output_buffer_, returned)) {
-            LOG(ERROR) << "Could not return buffer to sink";
-            return false;
-        }
-        output_buffer_ += returned;
-        output_buffer_remaining_ -= returned;
-
-        if (rv == Z_STREAM_END) {
-            if (z_.avail_in) {
-                LOG(ERROR) << "Gz stream ended prematurely";
-                return false;
-            }
-            decompressor_ended_ = true;
-            return true;
-        }
-    }
-    return true;
-}
-
 bool GzDecompressor::PartialDecompress(const uint8_t* data, size_t length) {
     z_.next_in = reinterpret_cast<Bytef*>(const_cast<uint8_t*>(data));
     z_.avail_in = length;
@@ -362,7 +217,6 @@
     ~BrotliDecompressor();
 
     bool Init() override;
-    bool DecompressInput(const uint8_t* data, size_t length) override;
     bool PartialDecompress(const uint8_t* data, size_t length) override;
 
   private:
@@ -380,31 +234,6 @@
     }
 }
 
-bool BrotliDecompressor::DecompressInput(const uint8_t* data, size_t length) {
-    size_t available_in = length;
-    const uint8_t* next_in = data;
-
-    bool needs_more_output = false;
-    while (available_in || needs_more_output) {
-        if (!output_buffer_remaining_ && !GetFreshBuffer()) {
-            return false;
-        }
-
-        auto output_buffer = output_buffer_;
-        auto r = BrotliDecoderDecompressStream(decoder_, &available_in, &next_in,
-                                               &output_buffer_remaining_, &output_buffer_, nullptr);
-        if (r == BROTLI_DECODER_RESULT_ERROR) {
-            LOG(ERROR) << "brotli decode failed";
-            return false;
-        }
-        if (!sink_->ReturnData(output_buffer, output_buffer_ - output_buffer)) {
-            return false;
-        }
-        needs_more_output = (r == BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT);
-    }
-    return true;
-}
-
 bool BrotliDecompressor::PartialDecompress(const uint8_t* data, size_t length) {
     size_t available_in = length;
     const uint8_t* next_in = data;
@@ -451,45 +280,6 @@
   public:
     ~Lz4Decompressor() override = default;
 
-    bool Decompress(const size_t output_size) override {
-        size_t actual_buffer_size = 0;
-        auto&& output_buffer = sink_->GetBuffer(output_size, &actual_buffer_size);
-        if (actual_buffer_size != output_size) {
-            LOG(ERROR) << "Failed to allocate buffer of size " << output_size << " only got "
-                       << actual_buffer_size << " bytes";
-            return false;
-        }
-        // If input size is same as output size, then input is uncompressed.
-        if (stream_->Size() == output_size) {
-            ssize_t bytes_read = stream_->ReadFully(output_buffer, output_size);
-            if (bytes_read != output_size) {
-                LOG(ERROR) << "Failed to read all input at once. Expected: " << output_size
-                           << " actual: " << bytes_read;
-                return false;
-            }
-            sink_->ReturnData(output_buffer, output_size);
-            return true;
-        }
-        std::string input_buffer;
-        input_buffer.resize(stream_->Size());
-        ssize_t bytes_read = stream_->ReadFully(input_buffer.data(), input_buffer.size());
-        if (bytes_read != input_buffer.size()) {
-            LOG(ERROR) << "Failed to read all input at once. Expected: " << input_buffer.size()
-                       << " actual: " << bytes_read;
-            return false;
-        }
-        const int bytes_decompressed =
-                LZ4_decompress_safe(input_buffer.data(), static_cast<char*>(output_buffer),
-                                    input_buffer.size(), output_size);
-        if (bytes_decompressed != output_size) {
-            LOG(ERROR) << "Failed to decompress LZ4 block, expected output size: " << output_size
-                       << ", actual: " << bytes_decompressed;
-            return false;
-        }
-        sink_->ReturnData(output_buffer, output_size);
-        return true;
-    }
-
     ssize_t Decompress(void* buffer, size_t buffer_size, size_t decompressed_size,
                        size_t ignore_bytes) override {
         std::string input_buffer(stream_->Size(), '\0');
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.h b/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.h
index 09164d3..9e83f3c 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.h
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_decompress.h
@@ -50,9 +50,6 @@
 
     static std::unique_ptr<IDecompressor> FromString(std::string_view compressor);
 
-    // |output_bytes| is the expected total number of bytes to sink.
-    virtual bool Decompress(size_t output_bytes) = 0;
-
     // Decompress at most |buffer_size| bytes, ignoring the first |ignore_bytes|
     // of the decoded stream. |buffer_size| must be at least one byte.
     // |decompressed_size| is the expected total size if the entire stream were
@@ -64,11 +61,9 @@
                                size_t ignore_bytes = 0) = 0;
 
     void set_stream(IByteStream* stream) { stream_ = stream; }
-    void set_sink(IByteSink* sink) { sink_ = sink; }
 
   protected:
     IByteStream* stream_ = nullptr;
-    IByteSink* sink_ = nullptr;
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
index e583ff0..3158106 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
@@ -770,38 +770,6 @@
     size_t remaining_;
 };
 
-bool CowReader::ReadData(const CowOperation& op, IByteSink* sink) {
-    std::unique_ptr<IDecompressor> decompressor;
-    switch (op.compression) {
-        case kCowCompressNone:
-            decompressor = IDecompressor::Uncompressed();
-            break;
-        case kCowCompressGz:
-            decompressor = IDecompressor::Gz();
-            break;
-        case kCowCompressBrotli:
-            decompressor = IDecompressor::Brotli();
-            break;
-        case kCowCompressLz4:
-            decompressor = IDecompressor::Lz4();
-            break;
-        default:
-            LOG(ERROR) << "Unknown compression type: " << op.compression;
-            return false;
-    }
-
-    uint64_t offset;
-    if (op.type == kCowXorOp) {
-        offset = data_loc_->at(op.new_block);
-    } else {
-        offset = op.source;
-    }
-    CowDataStream stream(this, offset, op.data_length);
-    decompressor->set_stream(&stream);
-    decompressor->set_sink(sink);
-    return decompressor->Decompress(header_.block_size);
-}
-
 ssize_t CowReader::ReadData(const CowOperation& op, void* buffer, size_t buffer_size,
                             size_t ignore_bytes) {
     std::unique_ptr<IDecompressor> decompressor;
diff --git a/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_buffer.h b/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_buffer.h
index 2e4cac6..a6b6a7f 100644
--- a/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_buffer.h
+++ b/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_buffer.h
@@ -25,16 +25,15 @@
 namespace android {
 namespace snapshot {
 
-class BufferSink : public IByteSink {
+class BufferSink final {
   public:
     void Initialize(size_t size);
     void* GetBufPtr() { return buffer_.get(); }
     void Clear() { memset(GetBufPtr(), 0, buffer_size_); }
     void* GetPayloadBuffer(size_t size);
-    void* GetBuffer(size_t requested, size_t* actual) override;
+    void* GetBuffer(size_t requested, size_t* actual);
     void UpdateBufferOffset(size_t size) { buffer_offset_ += size; }
     struct dm_user_header* GetHeaderPtr();
-    bool ReturnData(void*, size_t) override { return true; }
     void ResetBufferOffset() { buffer_offset_ = 0; }
     void* GetPayloadBufPtr();
 
@@ -44,12 +43,12 @@
     size_t buffer_size_;
 };
 
-class XorSink : public IByteSink {
+class XorSink final {
   public:
     void Initialize(BufferSink* sink, size_t size);
     void Reset();
-    void* GetBuffer(size_t requested, size_t* actual) override;
-    bool ReturnData(void* buffer, size_t len) override;
+    void* GetBuffer(size_t requested, size_t* actual);
+    bool ReturnData(void* buffer, size_t len);
 
   private:
     BufferSink* bufsink_;