diff --git a/fs_mgr/libsnapshot/cow_api_test.cpp b/fs_mgr/libsnapshot/cow_api_test.cpp
index 4db6584..35020f4 100644
--- a/fs_mgr/libsnapshot/cow_api_test.cpp
+++ b/fs_mgr/libsnapshot/cow_api_test.cpp
@@ -525,6 +525,165 @@
     ASSERT_TRUE(iter->Done());
 }
 
+TEST_F(CowTest, ClusterTest) {
+    CowOptions options;
+    options.cluster_ops = 4;
+    auto writer = std::make_unique<CowWriter>(options);
+    ASSERT_TRUE(writer->Initialize(cow_->fd));
+
+    std::string data = "This is some data, believe it";
+    data.resize(options.block_size, '\0');
+    ASSERT_TRUE(writer->AddRawBlocks(50, data.data(), data.size()));
+
+    ASSERT_TRUE(writer->AddLabel(4));
+
+    ASSERT_TRUE(writer->AddZeroBlocks(50, 2));  // Cluster split in middle
+
+    ASSERT_TRUE(writer->AddLabel(5));
+
+    ASSERT_TRUE(writer->AddCopy(5, 6));
+
+    // Cluster split
+
+    ASSERT_TRUE(writer->AddLabel(6));
+
+    ASSERT_TRUE(writer->Finalize());  // No data for cluster, so no cluster split needed
+
+    ASSERT_EQ(lseek(cow_->fd, 0, SEEK_SET), 0);
+
+    // Read back all ops
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    StringSink sink;
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+
+    ASSERT_FALSE(iter->Done());
+    auto op = &iter->Get();
+    ASSERT_EQ(op->type, kCowReplaceOp);
+    ASSERT_TRUE(reader.ReadData(*op, &sink));
+    ASSERT_EQ(sink.stream(), data.substr(0, options.block_size));
+
+    iter->Next();
+    sink.Reset();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowLabelOp);
+    ASSERT_EQ(op->source, 4);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowZeroOp);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowClusterOp);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowZeroOp);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowLabelOp);
+    ASSERT_EQ(op->source, 5);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowCopyOp);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowClusterOp);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowLabelOp);
+    ASSERT_EQ(op->source, 6);
+
+    iter->Next();
+
+    ASSERT_TRUE(iter->Done());
+}
+
+TEST_F(CowTest, ClusterAppendTest) {
+    CowOptions options;
+    options.cluster_ops = 3;
+    auto writer = std::make_unique<CowWriter>(options);
+    ASSERT_TRUE(writer->Initialize(cow_->fd));
+
+    ASSERT_TRUE(writer->AddLabel(50));
+    ASSERT_TRUE(writer->Finalize());  // Adds a cluster op, should be dropped on append
+
+    ASSERT_EQ(lseek(cow_->fd, 0, SEEK_SET), 0);
+
+    writer = std::make_unique<CowWriter>(options);
+    ASSERT_TRUE(writer->InitializeAppend(cow_->fd, 50));
+
+    std::string data2 = "More data!";
+    data2.resize(options.block_size, '\0');
+    ASSERT_TRUE(writer->AddRawBlocks(51, data2.data(), data2.size()));
+    ASSERT_TRUE(writer->Finalize());  // Adds a cluster op
+
+    ASSERT_EQ(lseek(cow_->fd, 0, SEEK_SET), 0);
+
+    struct stat buf;
+    ASSERT_EQ(fstat(cow_->fd, &buf), 0);
+    ASSERT_EQ(buf.st_size, writer->GetCowSize());
+
+    // Read back both operations, plus cluster op at end
+    CowReader reader;
+    uint64_t label;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+    ASSERT_TRUE(reader.GetLastLabel(&label));
+    ASSERT_EQ(label, 50);
+
+    StringSink sink;
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+
+    ASSERT_FALSE(iter->Done());
+    auto op = &iter->Get();
+    ASSERT_EQ(op->type, kCowLabelOp);
+    ASSERT_EQ(op->source, 50);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowReplaceOp);
+    ASSERT_TRUE(reader.ReadData(*op, &sink));
+    ASSERT_EQ(sink.stream(), data2);
+
+    iter->Next();
+
+    ASSERT_FALSE(iter->Done());
+    op = &iter->Get();
+    ASSERT_EQ(op->type, kCowClusterOp);
+
+    iter->Next();
+
+    ASSERT_TRUE(iter->Done());
+}
+
 }  // namespace snapshot
 }  // namespace android
 
diff --git a/fs_mgr/libsnapshot/cow_format.cpp b/fs_mgr/libsnapshot/cow_format.cpp
index 49ba11f..0753c49 100644
--- a/fs_mgr/libsnapshot/cow_format.cpp
+++ b/fs_mgr/libsnapshot/cow_format.cpp
@@ -35,6 +35,10 @@
         os << "kCowFooterOp,  ";
     else if (op.type == kCowLabelOp)
         os << "kCowLabelOp,   ";
+    else if (op.type == kCowClusterOp)
+        os << "kCowClusterOp  ";
+    else if (op.type == kCowFooterOp)
+        os << "kCowFooterOp  ";
     else
         os << (int)op.type << "?,";
     os << "compression:";
@@ -52,11 +56,35 @@
     return os;
 }
 
-int64_t GetNextOpOffset(const CowOperation& op) {
-    if (op.type == kCowReplaceOp)
+int64_t GetNextOpOffset(const CowOperation& op, uint32_t cluster_ops) {
+    if (op.type == kCowClusterOp) {
+        return op.source;
+    } else if (op.type == kCowReplaceOp && cluster_ops == 0) {
         return op.data_length;
-    else
+    } else {
         return 0;
+    }
+}
+
+int64_t GetNextDataOffset(const CowOperation& op, uint32_t cluster_ops) {
+    if (op.type == kCowClusterOp) {
+        return cluster_ops * sizeof(CowOperation);
+    } else if (cluster_ops == 0) {
+        return sizeof(CowOperation);
+    } else {
+        return 0;
+    }
+}
+
+bool IsMetadataOp(const CowOperation& op) {
+    switch (op.type) {
+        case kCowLabelOp:
+        case kCowClusterOp:
+        case kCowFooterOp:
+            return true;
+        default:
+            return false;
+    }
 }
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/cow_reader.cpp b/fs_mgr/libsnapshot/cow_reader.cpp
index 0907032..3fbc5f3 100644
--- a/fs_mgr/libsnapshot/cow_reader.cpp
+++ b/fs_mgr/libsnapshot/cow_reader.cpp
@@ -81,6 +81,24 @@
                    << sizeof(CowFooter);
         return false;
     }
+    if (header_.op_size != sizeof(CowOperation)) {
+        LOG(ERROR) << "Operation size unknown, read " << header_.op_size << ", expected "
+                   << sizeof(CowOperation);
+        return false;
+    }
+    if (header_.cluster_ops == 1) {
+        LOG(ERROR) << "Clusters must contain at least two operations to function.";
+        return false;
+    }
+    if (header_.op_size != sizeof(CowOperation)) {
+        LOG(ERROR) << "Operation size unknown, read " << header_.op_size << ", expected "
+                   << sizeof(CowOperation);
+        return false;
+    }
+    if (header_.cluster_ops == 1) {
+        LOG(ERROR) << "Clusters must contain at least two operations to function.";
+        return false;
+    }
 
     if ((header_.major_version != kCowVersionMajor) ||
         (header_.minor_version != kCowVersionMinor)) {
@@ -103,45 +121,64 @@
     }
 
     auto ops_buffer = std::make_shared<std::vector<CowOperation>>();
+    uint64_t current_op_num = 0;
+    uint64_t cluster_ops = header_.cluster_ops ?: 1;
+    bool done = false;
 
-    // Alternating op and data
-    while (true) {
-        ops_buffer->emplace_back();
-        if (!android::base::ReadFully(fd_, &ops_buffer->back(), sizeof(CowOperation))) {
+    // Alternating op clusters and data
+    while (!done) {
+        uint64_t to_add = std::min(cluster_ops, (fd_size_ - pos) / sizeof(CowOperation));
+        if (to_add == 0) break;
+        ops_buffer->resize(current_op_num + to_add);
+        if (!android::base::ReadFully(fd_, &ops_buffer->data()[current_op_num],
+                                      to_add * sizeof(CowOperation))) {
             PLOG(ERROR) << "read op failed";
             return false;
         }
+        // Parse current cluster to find start of next cluster
+        while (current_op_num < ops_buffer->size()) {
+            auto& current_op = ops_buffer->data()[current_op_num];
+            current_op_num++;
+            pos += sizeof(CowOperation) + GetNextOpOffset(current_op, header_.cluster_ops);
 
-        auto& current_op = ops_buffer->back();
-        off_t offs = lseek(fd_.get(), GetNextOpOffset(current_op), SEEK_CUR);
-        if (offs < 0) {
+            if (current_op.type == kCowClusterOp) {
+                break;
+            } else if (current_op.type == kCowLabelOp) {
+                last_label_ = {current_op.source};
+
+                // If we reach the requested label, stop reading.
+                if (label && label.value() == current_op.source) {
+                    done = true;
+                    break;
+                }
+            } else if (current_op.type == kCowFooterOp) {
+                footer_.emplace();
+                CowFooter* footer = &footer_.value();
+                memcpy(&footer_->op, &current_op, sizeof(footer->op));
+                off_t offs = lseek(fd_.get(), pos, SEEK_SET);
+                if (offs < 0 || pos != static_cast<uint64_t>(offs)) {
+                    PLOG(ERROR) << "lseek next op failed";
+                    return false;
+                }
+                if (!android::base::ReadFully(fd_, &footer->data, sizeof(footer->data))) {
+                    LOG(ERROR) << "Could not read COW footer";
+                    return false;
+                }
+
+                // Drop the footer from the op stream.
+                current_op_num--;
+                done = true;
+                break;
+            }
+        }
+
+        // Position for next cluster read
+        off_t offs = lseek(fd_.get(), pos, SEEK_SET);
+        if (offs < 0 || pos != static_cast<uint64_t>(offs)) {
             PLOG(ERROR) << "lseek next op failed";
             return false;
         }
-        pos = static_cast<uint64_t>(offs);
-
-        if (current_op.type == kCowLabelOp) {
-            last_label_ = {current_op.source};
-
-            // If we reach the requested label, stop reading.
-            if (label && label.value() == current_op.source) {
-                break;
-            }
-        } else if (current_op.type == kCowFooterOp) {
-            footer_.emplace();
-
-            CowFooter* footer = &footer_.value();
-            memcpy(&footer_->op, &current_op, sizeof(footer->op));
-
-            if (!android::base::ReadFully(fd_, &footer->data, sizeof(footer->data))) {
-                LOG(ERROR) << "Could not read COW footer";
-                return false;
-            }
-
-            // Drop the footer from the op stream.
-            ops_buffer->pop_back();
-            break;
-        }
+        ops_buffer->resize(current_op_num);
     }
 
     // To successfully parse a COW file, we need either:
@@ -198,9 +235,7 @@
 
     // Remove all the metadata operations
     ops_->erase(std::remove_if(ops_.get()->begin(), ops_.get()->end(),
-                               [](CowOperation& op) {
-                                   return (op.type == kCowFooterOp || op.type == kCowLabelOp);
-                               }),
+                               [](CowOperation& op) { return IsMetadataOp(op); }),
                 ops_.get()->end());
 
     // We will re-arrange the vector in such a way that
diff --git a/fs_mgr/libsnapshot/cow_writer.cpp b/fs_mgr/libsnapshot/cow_writer.cpp
index f7cc6ff..8535252 100644
--- a/fs_mgr/libsnapshot/cow_writer.cpp
+++ b/fs_mgr/libsnapshot/cow_writer.cpp
@@ -90,8 +90,10 @@
     header_.minor_version = kCowVersionMinor;
     header_.header_size = sizeof(CowHeader);
     header_.footer_size = sizeof(CowFooter);
+    header_.op_size = sizeof(CowOperation);
     header_.block_size = options_.block_size;
     header_.num_merge_ops = 0;
+    header_.cluster_ops = options_.cluster_ops;
     footer_ = {};
     footer_.op.data_length = 64;
     footer_.op.type = kCowFooterOp;
@@ -108,6 +110,10 @@
         LOG(ERROR) << "unrecognized compression: " << options_.compression;
         return false;
     }
+    if (options_.cluster_ops == 1) {
+        LOG(ERROR) << "Clusters must contain at least two operations to function.";
+        return false;
+    }
     return true;
 }
 
@@ -165,6 +171,19 @@
     return OpenForAppend(label);
 }
 
+void CowWriter::InitPos() {
+    next_op_pos_ = sizeof(header_);
+    cluster_size_ = header_.cluster_ops * sizeof(CowOperation);
+    if (header_.cluster_ops) {
+        next_data_pos_ = next_op_pos_ + cluster_size_;
+    } else {
+        next_data_pos_ = next_op_pos_ + sizeof(CowOperation);
+    }
+    ops_.clear();
+    current_cluster_size_ = 0;
+    current_data_size_ = 0;
+}
+
 bool CowWriter::OpenForWrite() {
     // This limitation is tied to the data field size in CowOperation.
     if (header_.block_size > std::numeric_limits<uint16_t>::max()) {
@@ -184,7 +203,7 @@
         return false;
     }
 
-    next_op_pos_ = sizeof(header_);
+    InitPos();
     return true;
 }
 
@@ -197,13 +216,14 @@
     }
 
     options_.block_size = header_.block_size;
+    options_.cluster_ops = header_.cluster_ops;
 
     // Reset this, since we're going to reimport all operations.
     footer_.op.num_ops = 0;
-    next_op_pos_ = sizeof(header_);
-    ops_.resize(0);
+    InitPos();
 
     auto iter = reader->GetOpIter();
+
     while (!iter->Done()) {
         AddOperation(iter->Get());
         iter->Next();
@@ -234,14 +254,12 @@
 
 bool CowWriter::EmitRawBlocks(uint64_t new_block_start, const void* data, size_t size) {
     const uint8_t* iter = reinterpret_cast<const uint8_t*>(data);
-    uint64_t pos;
     CHECK(!merge_in_progress_);
     for (size_t i = 0; i < size / header_.block_size; i++) {
         CowOperation op = {};
         op.type = kCowReplaceOp;
         op.new_block = new_block_start + i;
-        GetDataPos(&pos);
-        op.source = pos + sizeof(op);
+        op.source = next_data_pos_;
 
         if (compression_) {
             auto data = Compress(iter, header_.block_size);
@@ -293,6 +311,14 @@
     return WriteOperation(op) && Sync();
 }
 
+bool CowWriter::EmitCluster() {
+    CowOperation op = {};
+    op.type = kCowClusterOp;
+    // Next cluster starts after remainder of current cluster and the next data block.
+    op.source = current_data_size_ + cluster_size_ - current_cluster_size_ - sizeof(CowOperation);
+    return WriteOperation(op);
+}
+
 std::basic_string<uint8_t> CowWriter::Compress(const void* data, size_t length) {
     switch (compression_) {
         case kCowCompressGz: {
@@ -345,11 +371,23 @@
 }
 
 bool CowWriter::Finalize() {
-    footer_.op.ops_size = ops_.size();
-    uint64_t pos;
+    auto continue_cluster_size = current_cluster_size_;
+    auto continue_data_size = current_data_size_;
+    auto continue_data_pos = next_data_pos_;
+    auto continue_op_pos = next_op_pos_;
+    auto continue_size = ops_.size();
+    bool extra_cluster = false;
 
-    if (!GetDataPos(&pos)) {
-        PLOG(ERROR) << "failed to get file position";
+    // Footer should be at the end of a file, so if there is data after the current block, end it
+    // and start a new cluster.
+    if (cluster_size_ && current_data_size_ > 0) {
+        EmitCluster();
+        extra_cluster = true;
+    }
+
+    footer_.op.ops_size = ops_.size();
+    if (lseek(fd_.get(), next_op_pos_, SEEK_SET) < 0) {
+        PLOG(ERROR) << "Failed to seek to footer position.";
         return false;
     }
     memset(&footer_.data.ops_checksum, 0, sizeof(uint8_t) * 32);
@@ -364,16 +402,24 @@
         return false;
     }
 
-    // Re-position for any subsequent writes.
-    if (lseek(fd_.get(), pos, SEEK_SET) < 0) {
-        PLOG(ERROR) << "lseek ops failed";
-        return false;
+    // Reposition for additional Writing
+    if (extra_cluster) {
+        current_cluster_size_ = continue_cluster_size;
+        current_data_size_ = continue_data_size;
+        next_data_pos_ = continue_data_pos;
+        next_op_pos_ = continue_op_pos;
+        ops_.resize(continue_size);
     }
+
     return Sync();
 }
 
 uint64_t CowWriter::GetCowSize() {
-    return next_op_pos_ + sizeof(footer_);
+    if (current_data_size_ > 0) {
+        return next_data_pos_ + sizeof(footer_);
+    } else {
+        return next_op_pos_ + sizeof(footer_);
+    }
 }
 
 bool CowWriter::GetDataPos(uint64_t* pos) {
@@ -387,6 +433,15 @@
 }
 
 bool CowWriter::WriteOperation(const CowOperation& op, const void* data, size_t size) {
+    // If there isn't room for this op and the cluster end op, end the current cluster
+    if (cluster_size_ && op.type != kCowClusterOp &&
+        cluster_size_ < current_cluster_size_ + 2 * sizeof(op)) {
+        if (!EmitCluster()) return false;
+    }
+    if (lseek(fd_.get(), next_op_pos_, SEEK_SET) < 0) {
+        PLOG(ERROR) << "lseek failed for writing operation.";
+        return false;
+    }
     if (!android::base::WriteFully(fd_, reinterpret_cast<const uint8_t*>(&op), sizeof(op))) {
         return false;
     }
@@ -399,11 +454,26 @@
 
 void CowWriter::AddOperation(const CowOperation& op) {
     footer_.op.num_ops++;
-    next_op_pos_ += sizeof(CowOperation) + GetNextOpOffset(op);
+
+    if (op.type == kCowClusterOp) {
+        current_cluster_size_ = 0;
+        current_data_size_ = 0;
+    } else if (header_.cluster_ops) {
+        current_cluster_size_ += sizeof(op);
+        current_data_size_ += op.data_length;
+    }
+
+    next_data_pos_ += op.data_length + GetNextDataOffset(op, header_.cluster_ops);
+    next_op_pos_ += sizeof(CowOperation) + GetNextOpOffset(op, header_.cluster_ops);
     ops_.insert(ops_.size(), reinterpret_cast<const uint8_t*>(&op), sizeof(op));
 }
 
 bool CowWriter::WriteRawData(const void* data, size_t size) {
+    if (lseek(fd_.get(), next_data_pos_, SEEK_SET) < 0) {
+        PLOG(ERROR) << "lseek failed for writing data.";
+        return false;
+    }
+
     if (!android::base::WriteFully(fd_, data, size)) {
         return false;
     }
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h
index 80766ff..797b8ef 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h
@@ -57,9 +57,15 @@
     // Size of footer struct
     uint16_t footer_size;
 
+    // Size of op struct
+    uint16_t op_size;
+
     // The size of block operations, in bytes.
     uint32_t block_size;
 
+    // The number of ops to cluster together. 0 For no clustering. Cannot be 1.
+    uint32_t cluster_ops;
+
     // Tracks merge operations completed
     uint64_t num_merge_ops;
 } __attribute__((packed));
@@ -113,13 +119,15 @@
     // For copy operations, this is a block location in the source image.
     //
     // For replace operations, this is a byte offset within the COW's data
-    // section (eg, not landing within the header or metadata). It is an
+    // sections (eg, not landing within the header or metadata). It is an
     // absolute position within the image.
     //
     // For zero operations (replace with all zeroes), this is unused and must
     // be zero.
     //
     // For Label operations, this is the value of the applied label.
+    //
+    // For Cluster operations, this is the length of the following data region
     uint64_t source;
 } __attribute__((packed));
 
@@ -129,6 +137,7 @@
 static constexpr uint8_t kCowReplaceOp = 2;
 static constexpr uint8_t kCowZeroOp = 3;
 static constexpr uint8_t kCowLabelOp = 4;
+static constexpr uint8_t kCowClusterOp = 5;
 static constexpr uint8_t kCowFooterOp = -1;
 
 static constexpr uint8_t kCowCompressNone = 0;
@@ -142,7 +151,10 @@
 
 std::ostream& operator<<(std::ostream& os, CowOperation const& arg);
 
-int64_t GetNextOpOffset(const CowOperation& op);
+int64_t GetNextOpOffset(const CowOperation& op, uint32_t cluster_size);
+int64_t GetNextDataOffset(const CowOperation& op, uint32_t cluster_size);
+
+bool IsMetadataOp(const CowOperation& op);
 
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
index 36cd238..fd43cce 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
@@ -33,6 +33,9 @@
 
     // Maximum number of blocks that can be written.
     std::optional<uint64_t> max_blocks;
+
+    // Number of CowOperations in a cluster. 0 for no clustering. Cannot be 1.
+    uint32_t cluster_ops = 0;
 };
 
 // Interface for writing to a snapuserd COW. All operations are ordered; merges
@@ -111,6 +114,7 @@
     virtual bool EmitLabel(uint64_t label) override;
 
   private:
+    bool EmitCluster();
     void SetupHeaders();
     bool ParseOptions();
     bool OpenForWrite();
@@ -120,6 +124,7 @@
     bool WriteOperation(const CowOperation& op, const void* data = nullptr, size_t size = 0);
     void AddOperation(const CowOperation& op);
     std::basic_string<uint8_t> Compress(const void* data, size_t length);
+    void InitPos();
 
     bool SetFd(android::base::borrowed_fd fd);
     bool Sync();
@@ -132,6 +137,10 @@
     CowFooter footer_{};
     int compression_ = 0;
     uint64_t next_op_pos_ = 0;
+    uint64_t next_data_pos_ = 0;
+    uint32_t cluster_size_ = 0;
+    uint32_t current_cluster_size_ = 0;
+    uint64_t current_data_size_ = 0;
     bool is_dev_null_ = false;
     bool merge_in_progress_ = false;
     bool is_block_device_ = false;
diff --git a/fs_mgr/libsnapshot/inspect_cow.cpp b/fs_mgr/libsnapshot/inspect_cow.cpp
index 6046bad..5ad61f3 100644
--- a/fs_mgr/libsnapshot/inspect_cow.cpp
+++ b/fs_mgr/libsnapshot/inspect_cow.cpp
@@ -14,6 +14,7 @@
 // limitations under the License.
 //
 #include <stdio.h>
+#include <unistd.h>
 
 #include <iostream>
 #include <string>
@@ -34,7 +35,11 @@
     }
 }
 
-static bool Inspect(const std::string& path) {
+static void usage(void) {
+    LOG(ERROR) << "Usage: inspect_cow [-s] <COW_FILE>";
+}
+
+static bool Inspect(const std::string& path, bool silent) {
     android::base::unique_fd fd(open(path.c_str(), O_RDONLY));
     if (fd < 0) {
         PLOG(ERROR) << "open failed: " << path;
@@ -52,19 +57,29 @@
         LOG(ERROR) << "could not get header: " << path;
         return false;
     }
+    CowFooter footer;
+    bool has_footer = false;
+    if (reader.GetFooter(&footer)) has_footer = true;
 
-    std::cout << "Major version: " << header.major_version << "\n";
-    std::cout << "Minor version: " << header.minor_version << "\n";
-    std::cout << "Header size: " << header.header_size << "\n";
-    std::cout << "Footer size: " << header.footer_size << "\n";
-    std::cout << "Block size: " << header.block_size << "\n";
-    std::cout << "\n";
+    if (!silent) {
+        std::cout << "Major version: " << header.major_version << "\n";
+        std::cout << "Minor version: " << header.minor_version << "\n";
+        std::cout << "Header size: " << header.header_size << "\n";
+        std::cout << "Footer size: " << header.footer_size << "\n";
+        std::cout << "Block size: " << header.block_size << "\n";
+        std::cout << "\n";
+        if (has_footer) {
+            std::cout << "Total Ops size: " << footer.op.ops_size << "\n";
+            std::cout << "Number of Ops: " << footer.op.num_ops << "\n";
+            std::cout << "\n";
+        }
+    }
 
     auto iter = reader.GetOpIter();
     while (!iter->Done()) {
         const CowOperation& op = iter->Get();
 
-        std::cout << op << "\n";
+        if (!silent) std::cout << op << "\n";
 
         iter->Next();
     }
@@ -76,14 +91,25 @@
 }  // namespace android
 
 int main(int argc, char** argv) {
+    int ch;
+    bool silent = false;
+    while ((ch = getopt(argc, argv, "s")) != -1) {
+        switch (ch) {
+            case 's':
+                silent = true;
+                break;
+            default:
+                android::snapshot::usage();
+        }
+    }
     android::base::InitLogging(argv, android::snapshot::MyLogger);
 
-    if (argc < 2) {
-        LOG(ERROR) << "Usage: inspect_cow <COW_FILE>";
+    if (argc < optind + 1) {
+        android::snapshot::usage();
         return 1;
     }
 
-    if (!android::snapshot::Inspect(argv[1])) {
+    if (!android::snapshot::Inspect(argv[optind], silent)) {
         return 1;
     }
     return 0;
diff --git a/fs_mgr/libsnapshot/make_cow_from_ab_ota.cpp b/fs_mgr/libsnapshot/make_cow_from_ab_ota.cpp
index d0b8f52..6a5754d 100644
--- a/fs_mgr/libsnapshot/make_cow_from_ab_ota.cpp
+++ b/fs_mgr/libsnapshot/make_cow_from_ab_ota.cpp
@@ -53,6 +53,7 @@
 
 DEFINE_string(source_tf, "", "Source target files (dir or zip file) for incremental payloads");
 DEFINE_string(compression, "gz", "Compression type to use (none or gz)");
+DEFINE_uint32(cluster_ops, 0, "Number of Cow Ops per cluster (0 or >1)");
 
 void MyLogger(android::base::LogId, android::base::LogSeverity severity, const char*, const char*,
               unsigned int, const char* message) {
@@ -189,6 +190,7 @@
     CowOptions options;
     options.block_size = kBlockSize;
     options.compression = FLAGS_compression;
+    options.cluster_ops = FLAGS_cluster_ops;
 
     writer_ = std::make_unique<CowWriter>(options);
     if (!writer_->Initialize(std::move(fd))) {
diff --git a/fs_mgr/libsnapshot/snapshot_reader.cpp b/fs_mgr/libsnapshot/snapshot_reader.cpp
index b56d879..5ee8e25 100644
--- a/fs_mgr/libsnapshot/snapshot_reader.cpp
+++ b/fs_mgr/libsnapshot/snapshot_reader.cpp
@@ -90,7 +90,7 @@
     op_iter_ = cow_->GetOpIter();
     while (!op_iter_->Done()) {
         const CowOperation* op = &op_iter_->Get();
-        if (op->type == kCowLabelOp || op->type == kCowFooterOp) {
+        if (IsMetadataOp(*op)) {
             op_iter_->Next();
             continue;
         }
diff --git a/fs_mgr/libsnapshot/snapuserd.cpp b/fs_mgr/libsnapshot/snapuserd.cpp
index d1d2521..34254a3 100644
--- a/fs_mgr/libsnapshot/snapuserd.cpp
+++ b/fs_mgr/libsnapshot/snapuserd.cpp
@@ -545,7 +545,7 @@
         struct disk_exception* de =
                 reinterpret_cast<struct disk_exception*>((char*)de_ptr.get() + offset);
 
-        if (cow_op->type == kCowFooterOp || cow_op->type == kCowLabelOp) {
+        if (IsMetadataOp(*cow_op)) {
             cowop_riter_->Next();
             continue;
         }