Merge "Use target device mapper given mapper target" into main
diff --git a/debuggerd/debuggerd_test.cpp b/debuggerd/debuggerd_test.cpp
index c3e1302..a6d8226 100644
--- a/debuggerd/debuggerd_test.cpp
+++ b/debuggerd/debuggerd_test.cpp
@@ -94,7 +94,7 @@
     if (sigaction(SIGALRM, &new_sigaction, &old_sigaction) != 0) { \
       err(1, "sigaction failed");                                  \
     }                                                              \
-    alarm(seconds);                                                \
+    alarm(seconds * android::base::HwTimeoutMultiplier());         \
     auto value = expr;                                             \
     int saved_errno = errno;                                       \
     if (sigaction(SIGALRM, &old_sigaction, nullptr) != 0) {        \
@@ -2825,7 +2825,8 @@
     }
 
     prev_file = match[1];
-    unwindstack::Elf elf(unwindstack::Memory::CreateFileMemory(prev_file, 0).release());
+    auto elf_memory = unwindstack::Memory::CreateFileMemory(prev_file, 0);
+    unwindstack::Elf elf(elf_memory);
     if (!elf.Init() || !elf.valid()) {
       // Skipping invalid elf files.
       continue;
diff --git a/debuggerd/libdebuggerd/utility.cpp b/debuggerd/libdebuggerd/utility.cpp
index d71fc6c..15f09b3 100644
--- a/debuggerd/libdebuggerd/utility.cpp
+++ b/debuggerd/libdebuggerd/utility.cpp
@@ -382,8 +382,10 @@
           return "SEGV_MTEAERR";
         case SEGV_MTESERR:
           return "SEGV_MTESERR";
+        case SEGV_CPERR:
+          return "SEGV_CPERR";
       }
-      static_assert(NSIGSEGV == SEGV_MTESERR, "missing SEGV_* si_code");
+      static_assert(NSIGSEGV == SEGV_CPERR, "missing SEGV_* si_code");
       break;
     case SIGSYS:
       switch (si->si_code) {
diff --git a/fastboot/Android.bp b/fastboot/Android.bp
index 56cac88..f85d1de 100644
--- a/fastboot/Android.bp
+++ b/fastboot/Android.bp
@@ -446,3 +446,14 @@
     host_supported: true,
     export_include_dirs: ["."],
 }
+
+python_test_host {
+    name: "fastboot_integration_test",
+    main: "test_fastboot.py",
+    srcs: ["test_fastboot.py"],
+    data: [":fastboot"],
+    test_config: "fastboot_integration_test.xml",
+    test_options: {
+        unit_test: false,
+    },
+}
diff --git a/fastboot/fastboot_integration_test.xml b/fastboot/fastboot_integration_test.xml
new file mode 100644
index 0000000..ad14cab
--- /dev/null
+++ b/fastboot/fastboot_integration_test.xml
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2023 The Android Open Source Project
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+          http://www.apache.org/licenses/LICENSE-2.0
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<configuration description="Config to run fastboot integration tests">
+    <option name="test-suite-tag" value="fastboot_unittests" />
+    <test class="com.android.tradefed.testtype.python.PythonBinaryHostTest" >
+        <option name="par-file-name" value="fastboot_integration_test" />
+        <option name="test-timeout" value="1m" />
+    </test>
+</configuration>
\ No newline at end of file
diff --git a/fastboot/test_fastboot.py b/fastboot/test_fastboot.py
new file mode 100644
index 0000000..adcaec7
--- /dev/null
+++ b/fastboot/test_fastboot.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+"""Tests for the fastboot command line utility.
+"""
+
+import re
+import subprocess
+import unittest
+
+
+class DevicesTest(unittest.TestCase):
+    """Tests for `fastboot devices`."""
+
+
+    def test_devices(self):
+        """Ensure that the format of `fastboot devices` does not change.
+
+        `fastboot devices` should alternate between a line containing the
+        device's serial number and fastboot state and an empty line
+        """
+        output = subprocess.check_output(["fastboot", "devices"])
+
+        previous_line_was_empty = True
+        for line in output.decode().splitlines():
+            if previous_line_was_empty:
+                if not re.match(r"[a-zA-Z\d]+\s+(bootloader|fastbootd)", line):
+                    self.fail("%s does not match the expected format <serial no>\\s+(bootloader|fastbootd)" % line)
+                previous_line_was_empty = False
+            else:
+                if line:
+                    self.fail("Expected an empty line. Received '%s'" % line)
+                previous_line_was_empty = True
+
+        if len(output) == 0:
+            self.fail("Output is empty. Are any devices connected?")
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/fs_mgr/fs_mgr_vendor_overlay.cpp b/fs_mgr/fs_mgr_vendor_overlay.cpp
index bacfa4b..6b742e5 100644
--- a/fs_mgr/fs_mgr_vendor_overlay.cpp
+++ b/fs_mgr/fs_mgr_vendor_overlay.cpp
@@ -112,6 +112,7 @@
     // properties are loaded.
     static const auto vndk_version = android::base::GetProperty(kVndkVersionPropertyName, "");
     if (vndk_version.empty()) {
+        // Vendor overlay is disabled from VNDK deprecated devices.
         LINFO << "vendor overlay: vndk version not defined";
         return false;
     }
diff --git a/fs_mgr/include_fstab b/fs_mgr/include_fstab
deleted file mode 120000
index 728737f..0000000
--- a/fs_mgr/include_fstab
+++ /dev/null
@@ -1 +0,0 @@
-libfstab/include
\ No newline at end of file
diff --git a/fs_mgr/liblp/fuzzer/README.md b/fs_mgr/liblp/fuzzer/README.md
index f831e2e..015c59b 100644
--- a/fs_mgr/liblp/fuzzer/README.md
+++ b/fs_mgr/liblp/fuzzer/README.md
@@ -18,15 +18,14 @@
 9. alignmentOffset (parameter name: "alignment_offset")
 10. logicalBlockSize (parameter name: "logical_block_size")
 11. maxMetadataSize (parameter name: "max_metadata_size")
-12. numSlots (parameter name: "metadata_slot_count")
-13. deviceIndex (parameter name: "device_index")
-14. start (parameter name: "start")
-15. end (parameter name: "end")
-16. addedGroupName (parameter name: "group_name")
-17. partitionGroupName (parameter name: "partition_name")
-18. numSectors (parameter name: "num_sectors")
-19. physicalSector (parameter name: "physical_sector")
-20. resizedPartitionSize (parameter name: "requested_size")
+12. deviceIndex (parameter name: "device_index")
+13. start (parameter name: "start")
+14. end (parameter name: "end")
+15. addedGroupName (parameter name: "group_name")
+16. partitionGroupName (parameter name: "partition_name")
+17. numSectors (parameter name: "num_sectors")
+18. physicalSector (parameter name: "physical_sector")
+19. resizedPartitionSize (parameter name: "requested_size")
 
 | Parameter| Valid Values| Configured Value|
 |------------- |-------------| ----- |
@@ -41,7 +40,6 @@
 |`alignmentOffset`| Integer |Value obtained from FuzzedDataProvider|
 |`logicalBlockSize`| Integer |Value obtained from FuzzedDataProvider|
 |`maxMetadataSize`| Integer value from `0` to `10000` |Value obtained from FuzzedDataProvider|
-|`numSlots`| Integer value from `0` to `2` |Value obtained from FuzzedDataProvider|
 |`deviceIndex`| Integer |Value obtained from FuzzedDataProvider|
 |`start`| Integer |Value obtained from FuzzedDataProvider|
 |`end`| Integer |Value obtained from FuzzedDataProvider|
@@ -67,17 +65,15 @@
 1. kAttributeTypes (parameter name: "attribute")
 2. blockDevSize (parameter name: "blockdev_size")
 3. metadataMaxSize (parameter name: "metadata_max_size")
-4. metadataSlotCount (parameter name: "metadata_slot_count")
-5. partitionName (parameter name: "partition_name")
-6. data (parameter name: "data")
-7. imageName (parameter name: "image_name")
+4. partitionName (parameter name: "partition_name")
+5. data (parameter name: "data")
+6. imageName (parameter name: "image_name")
 
 | Parameter| Valid Values| Configured Value|
 |------------- |-------------| ----- |
 |`kAttributeTypes`| 1.`LP_PARTITION_ATTR_NONE`,<br/> 2.`LP_PARTITION_ATTR_READONLY`,<br/> 3.`LP_PARTITION_ATTR_SLOT_SUFFIXED`,<br/> 4.`LP_PARTITION_ATTR_UPDATED`,<br/> 5.`LP_PARTITION_ATTR_DISABLED`|Value obtained from FuzzedDataProvider|
 |`blockDevSize`| Integer value from `0` to `100000`|Value obtained from FuzzedDataProvider|
 |`metadataMaxSize`| Integer value from `0` to `10000` |Value obtained from FuzzedDataProvider|
-|`metadataSlotCount`| Integer value from `0` to `2` |Value obtained from FuzzedDataProvider|
 |`partitionName`| String |Value obtained from FuzzedDataProvider|
 |`data`| String |Value obtained from FuzzedDataProvider|
 |`imageName`| String |Value obtained from FuzzedDataProvider|
@@ -102,12 +98,11 @@
 4. logicalBlockSize (parameter name: "logical_block_size")
 5. blockDevSize (parameter name: "blockdev_size")
 6. metadataMaxSize (parameter name: "metadata_max_size")
-7. metadataSlotCount (parameter name: "metadata_slot_count")
-8. blockDeviceInfoName (parameter name: "block_device_info_name")
-9. numSectors (parameter name: "num_sectors")
-10. physicalSector (parameter name: "physical_sector")
-11. sparsify (parameter name: "sparsify")
-12. buffer (parameter name: "data")
+7. blockDeviceInfoName (parameter name: "block_device_info_name")
+8. numSectors (parameter name: "num_sectors")
+9. physicalSector (parameter name: "physical_sector")
+10. sparsify (parameter name: "sparsify")
+11. buffer (parameter name: "data")
 
 | Parameter| Valid Values| Configured Value|
 |------------- |-------------| ----- |
@@ -117,7 +112,6 @@
 |`logicalBlockSize`| Integer |Value obtained from FuzzedDataProvider|
 |`blockDevSize`| Integer value in multiples of `LP_SECTOR_SIZE`|Value obtained from FuzzedDataProvider|
 |`metadataMaxSize`| Integer value from `0` to `10000` |Value obtained from FuzzedDataProvider|
-|`metadataSlotCount`| Integer value from `0` to `2` |Value obtained from FuzzedDataProvider|
 |`blockDeviceInfoName`| String |Value obtained from FuzzedDataProvider|
 |`numSectors`| Integer value from `1` to `1000000` |Value obtained from FuzzedDataProvider|
 |`physicalSector`| Integer value from `1` to `1000000` |Value obtained from FuzzedDataProvider|
diff --git a/fs_mgr/liblp/fuzzer/liblp_apis_fuzzer.cpp b/fs_mgr/liblp/fuzzer/liblp_apis_fuzzer.cpp
index a15bc89..cb192ea 100644
--- a/fs_mgr/liblp/fuzzer/liblp_apis_fuzzer.cpp
+++ b/fs_mgr/liblp/fuzzer/liblp_apis_fuzzer.cpp
@@ -39,8 +39,6 @@
 static constexpr uint32_t kValidLogicalBlockSize = 4096;
 static constexpr uint32_t kMinMetadataSize = 0;
 static constexpr uint32_t kMaxMetadataSize = 10000;
-static constexpr uint32_t kMinSlot = 0;
-static constexpr uint32_t kMaxSlot = 10;
 static constexpr uint32_t kMinFactor = 0;
 static constexpr uint32_t kMaxFactor = 10;
 static constexpr uint32_t kMetadataGeometrySize = 4096;
@@ -108,7 +106,7 @@
     uint32_t randomMetadataMaxSize =
             mFdp.ConsumeIntegralInRange<uint32_t>(kMinMetadataSize, kMaxMetadataSize);
     uint32_t metadataMaxSize = mFdp.ConsumeBool() ? kMetadataSize : randomMetadataMaxSize;
-    uint32_t metadataSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(kMinSlot, kMaxSlot);
+    uint32_t metadataSlotCount = mFdp.ConsumeBool() ? 0 : 1;
     mBuilder = MetadataBuilder::New(blockDevSize, metadataMaxSize, metadataSlotCount);
 
     if (mBuilder.get()) {
@@ -128,14 +126,15 @@
         Partition* super = mBuilder->AddPartition(mSuperPartitionName, LP_PARTITION_ATTR_READONLY);
         mBuilder->AddPartition(mPartitionName, LP_PARTITION_ATTR_READONLY);
 
-        int64_t numSectors = mFdp.ConsumeBool() ? mFdp.ConsumeIntegralInRange<uint64_t>(
-                                                          kMinSectorValue, kMaxSectorValue)
-                                                : kValidNumSectors;
-        int64_t physicalSector = mFdp.ConsumeBool() ? mFdp.ConsumeIntegralInRange<uint64_t>(
+        if (super) {
+            int64_t numSectors = mFdp.ConsumeBool() ? mFdp.ConsumeIntegralInRange<uint64_t>(
                                                               kMinSectorValue, kMaxSectorValue)
-                                                    : kValidPhysicalSector;
-
-        mBuilder->AddLinearExtent(super, mBlockDeviceInfoName, numSectors, physicalSector);
+                                                    : kValidNumSectors;
+            int64_t physicalSector = mFdp.ConsumeBool() ? mFdp.ConsumeIntegralInRange<uint64_t>(
+                                                                  kMinSectorValue, kMaxSectorValue)
+                                                        : kValidPhysicalSector;
+            mBuilder->AddLinearExtent(super, mBlockDeviceInfoName, numSectors, physicalSector);
+        }
     }
 }
 
diff --git a/fs_mgr/liblp/fuzzer/liblp_builder_fuzzer.cpp b/fs_mgr/liblp/fuzzer/liblp_builder_fuzzer.cpp
index e5fbe27..7f09ac8 100644
--- a/fs_mgr/liblp/fuzzer/liblp_builder_fuzzer.cpp
+++ b/fs_mgr/liblp/fuzzer/liblp_builder_fuzzer.cpp
@@ -48,8 +48,6 @@
 static constexpr uint32_t kZeroAlignment = 0;
 static constexpr uint32_t kZeroAlignmentOffset = 0;
 static constexpr uint32_t kMaxBytes = 20;
-static constexpr uint32_t kMinSlot = 0;
-static constexpr uint32_t kMaxSlot = 10;
 static constexpr uint32_t kMinBuilder = 0;
 static constexpr uint32_t kMaxBuilder = 4;
 
@@ -108,9 +106,7 @@
     switch (randomBuilder) {
         case 0: {
             uint32_t maxMetadataSize = getParamValue(kValidMaxMetadataSize);
-            uint32_t numSlots = mFdp.ConsumeBool()
-                                        ? kMaxSlot
-                                        : mFdp.ConsumeIntegralInRange<uint32_t>(kMinSlot, kMaxSlot);
+            uint32_t numSlots = mFdp.ConsumeBool() ? 0 : 1;
             mBuilder = MetadataBuilder::New(mBlockDevices, superBlockDeviceName, maxMetadataSize,
                                             numSlots);
             break;
@@ -120,14 +116,14 @@
                     mFdp.ConsumeIntegralInRange<uint64_t>(kMinBlockDevValue, kMaxBlockDevValue);
             uint32_t metadataMaxSize =
                     mFdp.ConsumeIntegralInRange<uint32_t>(kMinMetadataValue, kMaxMetadataValue);
-            uint32_t metadataSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(kMinSlot, kMaxSlot);
+            uint32_t metadataSlotCount = mFdp.ConsumeBool() ? 0 : 1;
             mBuilder = MetadataBuilder::New(blockDevSize, metadataMaxSize, metadataSlotCount);
             break;
         }
         case 2: {
             uint64_t blockDevSize = getParamValue(kValidBlockSize);
             uint32_t metadataSize = getParamValue(kValidMetadataSize);
-            uint32_t metadataSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(kMinSlot, kMaxSlot);
+            uint32_t metadataSlotCount = mFdp.ConsumeBool() ? 0 : 1;
             mBuilder = MetadataBuilder::New(blockDevSize, metadataSize, metadataSlotCount);
             break;
         }
@@ -213,13 +209,13 @@
 void BuilderFuzzer::callVerifyExtentsAgainstSourceMetadata() {
     uint64_t sourceBlockDevSize = getParamValue(kValidBlockSize);
     uint32_t sourceMetadataMaxSize = getParamValue(kValidMetadataSize);
-    uint32_t sourceSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(0, 2);
+    uint32_t sourceSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(0, 1);
     auto sourceBuilder =
             MetadataBuilder::New(sourceBlockDevSize, sourceMetadataMaxSize, sourceSlotCount);
 
     uint64_t targetBlockDevSize = getParamValue(kValidBlockSize);
     uint32_t targetMetadataMaxSize = getParamValue(kValidMetadataSize);
-    uint32_t targetSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(0, 2);
+    uint32_t targetSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(0, 1);
     auto targetBuilder =
             MetadataBuilder::New(targetBlockDevSize, targetMetadataMaxSize, targetSlotCount);
 
@@ -292,17 +288,20 @@
 
                         int64_t numExtents =
                                 mFdp.ConsumeIntegralInRange<int64_t>(kMinElements, kMaxElements);
-                        bool extentAdded = false;
-                        for (int64_t i = 0; i <= numExtents; ++i) {
-                            extentAdded = mBuilder->AddLinearExtent(mFuzzPartition, kDeviceInfoName,
-                                                                    numSectors, physicalSector);
-                        }
+                        if (mFuzzPartition) {
+                            bool extentAdded = false;
+                            for (int64_t i = 0; i <= numExtents; ++i) {
+                                extentAdded =
+                                        mBuilder->AddLinearExtent(mFuzzPartition, kDeviceInfoName,
+                                                                  numSectors, physicalSector);
+                            }
 
-                        if (extentAdded) {
-                            unique_ptr<LpMetadata> metadata = mBuilder->Export();
-                            uint64_t alignedSize =
-                                    mFdp.ConsumeIntegralInRange<uint64_t>(kMinValue, kMaxValue);
-                            mFuzzPartition->GetBeginningExtents(LP_SECTOR_SIZE * numExtents);
+                            if (extentAdded) {
+                                unique_ptr<LpMetadata> metadata = mBuilder->Export();
+                                uint64_t alignedSize =
+                                        mFdp.ConsumeIntegralInRange<uint64_t>(kMinValue, kMaxValue);
+                                mFuzzPartition->GetBeginningExtents(LP_SECTOR_SIZE * numExtents);
+                            }
                         }
                     },
                     [&]() { callVerifyExtentsAgainstSourceMetadata(); },
diff --git a/fs_mgr/liblp/fuzzer/liblp_super_layout_builder_fuzzer.cpp b/fs_mgr/liblp/fuzzer/liblp_super_layout_builder_fuzzer.cpp
index 887093c..a6642d7 100644
--- a/fs_mgr/liblp/fuzzer/liblp_super_layout_builder_fuzzer.cpp
+++ b/fs_mgr/liblp/fuzzer/liblp_super_layout_builder_fuzzer.cpp
@@ -38,8 +38,6 @@
 static constexpr uint32_t kMinMetadataValue = 0;
 static constexpr uint32_t kMaxMetadataValue = 10000;
 static constexpr uint32_t kMaxBytes = 20;
-static constexpr uint32_t kMinSlot = 0;
-static constexpr uint32_t kMaxSlot = 10;
 static constexpr uint32_t kMinOpen = 0;
 static constexpr uint32_t kMaxOpen = 2;
 
@@ -58,14 +56,14 @@
     void invokeSuperLayoutBuilderAPIs();
     void callRandomOpen(int32_t open);
     void addMultiplePartitions(int32_t numPartitions);
-    void setupSuperLayoutBuilder(string fuzzPartitionName);
+    void setupSuperLayoutBuilder();
     SuperLayoutBuilder mSuperLayoutBuilder;
     unique_ptr<MetadataBuilder> mSuperBuilder;
     unique_ptr<LpMetadata> mMetadata;
     bool mOpenSuccess = false;
 };
 
-void SuperLayoutBuilderFuzzer::setupSuperLayoutBuilder(string fuzzPartitionName) {
+void SuperLayoutBuilderFuzzer::setupSuperLayoutBuilder() {
     uint64_t randomBlockDevSize =
             mFdp.ConsumeIntegralInRange<uint64_t>(kMinBlockDevValue, kMaxBlockDevValue);
     uint64_t blockDevSize = mFdp.ConsumeBool() ? kSuperLayoutValidBlockDevSize : randomBlockDevSize;
@@ -73,7 +71,7 @@
             mFdp.ConsumeIntegralInRange<uint32_t>(kMinMetadataValue, kMaxMetadataValue);
     uint32_t metadataMaxSize =
             mFdp.ConsumeBool() ? kSuperLayoutValidMetadataSize : randomMetadataMaxSize;
-    uint32_t metadataSlotCount = mFdp.ConsumeIntegralInRange<uint32_t>(kMinSlot, kMaxSlot);
+    uint32_t metadataSlotCount = mFdp.ConsumeBool() ? 0 : 1;
     mSuperBuilder = MetadataBuilder::New(blockDevSize, metadataMaxSize, metadataSlotCount);
 
     if (mSuperBuilder.get()) {
@@ -85,10 +83,6 @@
 
         uint32_t randomOpen = mFdp.ConsumeIntegralInRange<uint32_t>(kMinOpen, kMaxOpen);
         callRandomOpen(randomOpen);
-
-        if (!fuzzPartitionName.size()) {
-            fuzzPartitionName = "builder_partition";
-        }
     }
 }
 
@@ -125,7 +119,10 @@
     string imageName = mFdp.ConsumeRandomLengthString(kMaxBytes);
     string fuzzPartitionName =
             mFdp.ConsumeBool() ? "builder_partition" : mFdp.ConsumeRandomLengthString(kMaxBytes);
-    setupSuperLayoutBuilder(fuzzPartitionName);
+    if (!fuzzPartitionName.size()) {
+        fuzzPartitionName = "builder_partition";
+    }
+    setupSuperLayoutBuilder();
     if (mOpenSuccess) {
         while (mFdp.remaining_bytes()) {
             auto invokeSuperAPIs = mFdp.PickValueInArray<const function<void()>>({
diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index 6fad662..a8a7716 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -198,6 +198,7 @@
         "libsnapshot_cow/cow_format.cpp",
         "libsnapshot_cow/cow_reader.cpp",
         "libsnapshot_cow/parser_v2.cpp",
+        "libsnapshot_cow/parser_v3.cpp",
         "libsnapshot_cow/snapshot_reader.cpp",
         "libsnapshot_cow/writer_base.cpp",
         "libsnapshot_cow/writer_v2.cpp",
@@ -419,6 +420,7 @@
     },
     data: [
         "tools/testdata/cow_v2",
+        "tools/testdata/incompressible_block",
     ],
     auto_gen_config: true,
     require_root: false,
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h
index c9777a3..75467cb 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_format.h
@@ -94,13 +94,27 @@
 
 } __attribute__((packed));
 
+// Resume point structure used for resume buffer
+struct ResumePoint {
+    // monotonically increasing value used by update_engine
+    uint64_t label;
+    // Index of last CowOperation guaranteed to be resumable
+    uint32_t op_index;
+} __attribute__((packed));
+
+static constexpr uint8_t kNumResumePoints = 4;
+
 struct CowHeaderV3 : public CowHeader {
     // Location of sequence buffer in COW.
     uint64_t sequence_buffer_offset;
+    // number of currently written resume points
+    uint32_t resume_point_count;
     // Size, in bytes, of the CowResumePoint buffer.
-    uint32_t resume_buffer_size;
-    // Size, in bytes, of the CowOperation buffer.
-    uint32_t op_buffer_size;
+    uint32_t resume_point_max;
+    // Number of CowOperationV3 structs in the operation buffer, currently and total
+    // region size.
+    uint32_t op_count;
+    uint32_t op_count_max;
     // Compression Algorithm
     uint32_t compression_algorithm;
 } __attribute__((packed));
@@ -218,6 +232,19 @@
     return op.source_info & kCowOpSourceInfoDataMask;
 }
 
+static constexpr off_t GetOpOffset(uint32_t op_index, const CowHeaderV3 header) {
+    return header.prefix.header_size + header.buffer_size +
+           (header.resume_point_max * sizeof(ResumePoint)) + (op_index * sizeof(CowOperationV3));
+}
+static constexpr off_t GetDataOffset(const CowHeaderV3 header) {
+    return header.prefix.header_size + header.buffer_size +
+           (header.resume_point_max * sizeof(ResumePoint)) +
+           header.op_count_max * sizeof(CowOperation);
+}
+static constexpr off_t GetResumeOffset(const CowHeaderV3 header) {
+    return header.prefix.header_size + header.buffer_size;
+}
+
 struct CowFooter {
     CowFooterOperation op;
     uint8_t unused[64];
@@ -243,6 +270,8 @@
 
 std::ostream& operator<<(std::ostream& os, CowOperation const& arg);
 
+std::ostream& operator<<(std::ostream& os, ResumePoint const& arg);
+
 int64_t GetNextOpOffset(const CowOperationV2& op, uint32_t cluster_size);
 int64_t GetNextDataOffset(const CowOperationV2& op, uint32_t cluster_size);
 
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
index debaf36..c87b32d 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_reader.h
@@ -16,6 +16,7 @@
 
 #include <stdint.h>
 
+#include <deque>
 #include <functional>
 #include <memory>
 #include <optional>
@@ -145,6 +146,7 @@
                      size_t ignore_bytes = 0) override;
 
     CowHeader& GetHeader() override { return header_; }
+    const CowHeaderV3& header_v3() const { return header_; }
 
     bool GetRawBytes(const CowOperation* op, void* buffer, size_t len, size_t* read);
     bool GetRawBytes(uint64_t offset, void* buffer, size_t len, size_t* read);
@@ -182,16 +184,14 @@
     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_{};
-    uint8_t compression_type_ = kCowCompressNone;
 };
 
 // Though this function takes in a CowHeaderV3, the struct could be populated as a v1/v2 CowHeader.
 // The extra fields will just be filled as 0. V3 header is strictly a superset of v1/v2 header and
 // contains all of the latter's field
 bool ReadCowHeader(android::base::borrowed_fd fd, CowHeaderV3* header);
-
 }  // 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 3016e93..5b1e56c 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/cow_writer.h
@@ -54,6 +54,9 @@
 
     // Batch write cluster ops
     bool batch_write = false;
+
+    // Size of the cow operation buffer; used in v3 only.
+    uint32_t op_count_max = 0;
 };
 
 // Interface for writing to a snapuserd COW. All operations are ordered; merges
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_format.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_format.cpp
index b905291..937065d 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_format.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_format.cpp
@@ -100,6 +100,11 @@
     return os;
 }
 
+std::ostream& operator<<(std::ostream& os, ResumePoint const& resume_point) {
+    os << "ResumePoint(" << resume_point.label << " , " << resume_point.op_index << ")";
+    return os;
+}
+
 int64_t GetNextOpOffset(const CowOperationV2& op, uint32_t cluster_ops) {
     if (op.type == kCowClusterOp) {
         return op.source;
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
index 3b84c95..8412879 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/cow_reader.cpp
@@ -28,8 +28,8 @@
 #include <zlib.h>
 
 #include "cow_decompress.h"
-#include "libsnapshot/cow_format.h"
 #include "parser_v2.h"
+#include "parser_v3.h"
 
 namespace android {
 namespace snapshot {
@@ -82,10 +82,9 @@
     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_;
-    cow->compression_type_ = compression_type_;
     return cow;
 }
 
@@ -104,11 +103,14 @@
         PLOG(ERROR) << "lseek header failed";
         return false;
     }
-    if (!android::base::ReadFully(fd_, &header_, sizeof(header_))) {
+
+    CHECK_GE(header_.prefix.header_size, sizeof(CowHeader));
+    CHECK_LE(header_.prefix.header_size, sizeof(header_));
+
+    if (!android::base::ReadFully(fd_, &header_, header_.prefix.header_size)) {
         PLOG(ERROR) << "read header failed";
         return false;
     }
-
     return true;
 }
 
@@ -124,52 +126,35 @@
         return false;
     }
 
-    CowParserV2 parser;
-    if (!parser.Parse(fd, header_, label)) {
+    std::unique_ptr<CowParserBase> parser;
+    switch (header_.prefix.major_version) {
+        case 1:
+        case 2:
+            parser = std::make_unique<CowParserV2>();
+            break;
+        case 3:
+            parser = std::make_unique<CowParserV3>();
+            break;
+        default:
+            LOG(ERROR) << "Unknown version: " << header_.prefix.major_version;
+            return false;
+    }
+    if (!parser->Parse(fd, header_, label)) {
         return false;
     }
 
-    footer_ = parser.footer();
-    fd_size_ = parser.fd_size();
-    last_label_ = parser.last_label();
-    data_loc_ = parser.data_loc();
-    ops_ = std::make_shared<std::vector<CowOperation>>(parser.ops()->size());
-
-    // Translate the operation buffer from on disk to in memory
-    for (size_t i = 0; i < parser.ops()->size(); i++) {
-        const auto& v2_op = parser.ops()->at(i);
-
-        auto& new_op = ops_->at(i);
-        new_op.type = v2_op.type;
-        new_op.data_length = v2_op.data_length;
-
-        if (v2_op.new_block > std::numeric_limits<uint32_t>::max()) {
-            LOG(ERROR) << "Out-of-range new block in COW op: " << v2_op;
-            return false;
-        }
-        new_op.new_block = v2_op.new_block;
-
-        uint64_t source_info = v2_op.source;
-        if (new_op.type != kCowLabelOp) {
-            source_info &= kCowOpSourceInfoDataMask;
-            if (source_info != v2_op.source) {
-                LOG(ERROR) << "Out-of-range source value in COW op: " << v2_op;
-                return false;
-            }
-        }
-        if (v2_op.compression != kCowCompressNone) {
-            if (compression_type_ == kCowCompressNone) {
-                compression_type_ = v2_op.compression;
-            } else if (compression_type_ != v2_op.compression) {
-                LOG(ERROR) << "COW has mixed compression types which is not supported;"
-                           << " previously saw " << compression_type_ << ", got "
-                           << v2_op.compression << ", op: " << v2_op;
-                return false;
-            }
-        }
-        new_op.source_info = source_info;
+    TranslatedCowOps ops_info;
+    if (!parser->Translate(&ops_info)) {
+        return false;
     }
 
+    header_ = ops_info.header;
+    ops_ = std::move(ops_info.ops);
+    footer_ = parser->footer();
+    fd_size_ = parser->fd_size();
+    last_label_ = parser->last_label();
+    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;
     return PrepMergeOps();
@@ -615,8 +600,8 @@
 
 bool CowReader::GetRawBytes(uint64_t offset, void* buffer, size_t len, size_t* read) {
     // Validate the offset, taking care to acknowledge possible overflow of offset+len.
-    if (offset < header_.prefix.header_size || offset >= fd_size_ - sizeof(CowFooter) ||
-        len >= fd_size_ || offset + len > fd_size_ - sizeof(CowFooter)) {
+    if (offset < header_.prefix.header_size || offset >= fd_size_ || offset + len > fd_size_ ||
+        len >= fd_size_) {
         LOG(ERROR) << "invalid data offset: " << offset << ", " << len << " bytes";
         return false;
     }
@@ -664,7 +649,7 @@
 };
 
 uint8_t CowReader::GetCompressionType() {
-    return compression_type_;
+    return header_.compression_algorithm;
 }
 
 ssize_t CowReader::ReadData(const CowOperation* op, void* buffer, size_t buffer_size,
@@ -696,12 +681,12 @@
 
     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) {
+    if (!decompressor ||
+        ((op->data_length == header_.block_size) && (header_.prefix.major_version == 3))) {
         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 a291469..993630b 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/inspect_cow.cpp
@@ -74,15 +74,16 @@
     }
 }
 
-static bool ShowRawOpStreamV2(borrowed_fd fd, const CowHeader& header) {
+static bool ShowRawOpStreamV2(borrowed_fd fd, const CowHeaderV3& header) {
     CowParserV2 parser;
     if (!parser.Parse(fd, header)) {
         LOG(ERROR) << "v2 parser failed";
         return false;
     }
-    for (const auto& op : *parser.ops()) {
+    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
new file mode 100644
index 0000000..837b33e
--- /dev/null
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_base.h
@@ -0,0 +1,56 @@
+//
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#pragma once
+
+#include <optional>
+#include <unordered_map>
+
+#include <android-base/unique_fd.h>
+#include <libsnapshot/cow_format.h>
+
+namespace android {
+namespace snapshot {
+
+struct TranslatedCowOps {
+    CowHeaderV3 header;
+    std::shared_ptr<std::vector<CowOperationV3>> ops;
+};
+
+class CowParserBase {
+  public:
+    virtual ~CowParserBase() = default;
+
+    virtual bool Parse(android::base::borrowed_fd fd, const CowHeaderV3& header,
+                       std::optional<uint64_t> label = {}) = 0;
+    virtual bool Translate(TranslatedCowOps* out) = 0;
+    virtual std::optional<CowFooter> footer() const { return std::nullopt; }
+    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_; }
+
+  protected:
+    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
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp
index 8f20317..08a43a4 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.cpp
@@ -18,12 +18,14 @@
 #include <android-base/file.h>
 #include <android-base/logging.h>
 
+#include <libsnapshot/cow_format.h>
+
 namespace android {
 namespace snapshot {
 
 using android::base::borrowed_fd;
 
-bool CowParserV2::Parse(borrowed_fd fd, const CowHeader& header, std::optional<uint64_t> label) {
+bool CowParserV2::Parse(borrowed_fd fd, const CowHeaderV3& header, std::optional<uint64_t> label) {
     auto pos = lseek(fd.get(), 0, SEEK_END);
     if (pos < 0) {
         PLOG(ERROR) << "lseek end failed";
@@ -47,8 +49,7 @@
         return false;
     }
 
-    if ((header_.prefix.major_version > kCowVersionMajor) ||
-        (header_.prefix.minor_version != kCowVersionMinor)) {
+    if (header_.prefix.major_version > 2 || header_.prefix.minor_version != 0) {
         LOG(ERROR) << "Header version mismatch, "
                    << "major version: " << header_.prefix.major_version
                    << ", expected: " << kCowVersionMajor
@@ -62,7 +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)) {
@@ -110,7 +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);
@@ -190,9 +191,51 @@
         }
     }
 
-    ops_ = ops_buffer;
-    ops_->shrink_to_fit();
-    data_loc_ = data_loc;
+    v2_ops_ = ops_buffer;
+    v2_ops_->shrink_to_fit();
+    xor_data_loc_ = xor_data_loc;
+    return true;
+}
+
+bool CowParserV2::Translate(TranslatedCowOps* out) {
+    out->ops = std::make_shared<std::vector<CowOperationV3>>(v2_ops_->size());
+
+    // Translate the operation buffer from on disk to in memory
+    for (size_t i = 0; i < out->ops->size(); i++) {
+        const auto& v2_op = v2_ops_->at(i);
+
+        auto& new_op = out->ops->at(i);
+        new_op.type = v2_op.type;
+        new_op.data_length = v2_op.data_length;
+
+        if (v2_op.new_block > std::numeric_limits<uint32_t>::max()) {
+            LOG(ERROR) << "Out-of-range new block in COW op: " << v2_op;
+            return false;
+        }
+        new_op.new_block = v2_op.new_block;
+
+        uint64_t source_info = v2_op.source;
+        if (new_op.type != kCowLabelOp) {
+            source_info &= kCowOpSourceInfoDataMask;
+            if (source_info != v2_op.source) {
+                LOG(ERROR) << "Out-of-range source value in COW op: " << v2_op;
+                return false;
+            }
+        }
+        if (v2_op.compression != kCowCompressNone) {
+            if (header_.compression_algorithm == kCowCompressNone) {
+                header_.compression_algorithm = v2_op.compression;
+            } else if (header_.compression_algorithm != v2_op.compression) {
+                LOG(ERROR) << "COW has mixed compression types which is not supported;"
+                           << " previously saw " << header_.compression_algorithm << ", got "
+                           << v2_op.compression << ", op: " << v2_op;
+                return false;
+            }
+        }
+        new_op.source_info = source_info;
+    }
+
+    out->header = header_;
     return true;
 }
 
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h
index f51ff88..f9ee2e5 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v2.h
@@ -17,36 +17,29 @@
 
 #include <memory>
 #include <optional>
-#include <unordered_map>
 #include <vector>
 
 #include <android-base/unique_fd.h>
 #include <libsnapshot/cow_format.h>
+#include <libsnapshot_cow/parser_base.h>
 
 namespace android {
 namespace snapshot {
 
-class CowParserV2 {
+class CowParserV2 final : public CowParserBase {
   public:
-    bool Parse(android::base::borrowed_fd fd, const CowHeader& header,
-               std::optional<uint64_t> label = {});
+    bool Parse(android::base::borrowed_fd fd, const CowHeaderV3& header,
+               std::optional<uint64_t> label = {}) override;
+    bool Translate(TranslatedCowOps* out) override;
+    std::optional<CowFooter> footer() const override { return footer_; }
 
     const CowHeader& header() const { return header_; }
-    const std::optional<CowFooter>& footer() const { return footer_; }
-    std::shared_ptr<std::vector<CowOperationV2>> ops() { return ops_; }
-    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc() const { return data_loc_; }
-    uint64_t fd_size() const { return fd_size_; }
-    const std::optional<uint64_t>& last_label() const { return last_label_; }
+    std::shared_ptr<std::vector<CowOperationV2>> get_v2ops() { return v2_ops_; }
 
   private:
     bool ParseOps(android::base::borrowed_fd fd, std::optional<uint64_t> label);
-
-    CowHeader header_ = {};
+    std::shared_ptr<std::vector<CowOperationV2>> v2_ops_;
     std::optional<CowFooter> footer_;
-    std::shared_ptr<std::vector<CowOperationV2>> ops_;
-    std::shared_ptr<std::unordered_map<uint64_t, uint64_t>> data_loc_;
-    uint64_t fd_size_;
-    std::optional<uint64_t> last_label_;
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp
new file mode 100644
index 0000000..52c6348
--- /dev/null
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.cpp
@@ -0,0 +1,136 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#include "parser_v3.h"
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/strings.h>
+
+#include <libsnapshot/cow_format.h>
+#include <libsnapshot/cow_reader.h>
+
+namespace android {
+namespace snapshot {
+
+using android::base::borrowed_fd;
+
+bool CowParserV3::Parse(borrowed_fd fd, const CowHeaderV3& header, std::optional<uint64_t> label) {
+    auto pos = lseek(fd.get(), 0, SEEK_END);
+    if (pos < 0) {
+        PLOG(ERROR) << "lseek end failed";
+        return false;
+    }
+    fd_size_ = pos;
+    header_ = header;
+
+    if (header_.footer_size != 0) {
+        LOG(ERROR) << "Footer size isn't 0, read " << header_.footer_size;
+        return false;
+    }
+
+    if (header_.op_size != sizeof(CowOperationV3)) {
+        LOG(ERROR) << "Operation size unknown, read " << header_.op_size << ", expected "
+                   << sizeof(CowOperationV3);
+        return false;
+    }
+    if (header_.cluster_ops != 0) {
+        LOG(ERROR) << "Cluster ops not supported in v3";
+        return false;
+    }
+
+    if (header_.prefix.major_version != 3 || header_.prefix.minor_version != 0) {
+        LOG(ERROR) << "Header version mismatch, "
+                   << "major version: " << header_.prefix.major_version
+                   << ", expected: " << kCowVersionMajor
+                   << ", minor version: " << header_.prefix.minor_version
+                   << ", expected: " << kCowVersionMinor;
+        return false;
+    }
+
+    std::optional<uint32_t> op_index = header_.op_count;
+    if (label) {
+        if (!ReadResumeBuffer(fd)) {
+            PLOG(ERROR) << "Failed to read resume buffer";
+            return false;
+        }
+        op_index = FindResumeOp(label.value());
+        if (op_index == std::nullopt) {
+            LOG(ERROR) << "failed to get op index from given label: " << label.value();
+            return false;
+        }
+    }
+
+    return ParseOps(fd, op_index.value());
+}
+
+bool CowParserV3::ReadResumeBuffer(borrowed_fd fd) {
+    resume_points_ = std::make_shared<std::vector<ResumePoint>>(header_.resume_point_count);
+
+    return android::base::ReadFullyAtOffset(fd, resume_points_->data(),
+                                            header_.resume_point_count * sizeof(ResumePoint),
+                                            header_.prefix.header_size + header_.buffer_size);
+}
+
+std::optional<uint32_t> CowParserV3::FindResumeOp(const uint64_t label) {
+    for (auto& resume_point : *resume_points_) {
+        if (resume_point.label == label) {
+            return resume_point.op_index;
+        }
+    }
+    LOG(ERROR) << "failed to find label: " << label << "from following labels";
+    LOG(ERROR) << android::base::Join(*resume_points_, " ");
+
+    return std::nullopt;
+}
+
+bool CowParserV3::ParseOps(borrowed_fd fd, const uint32_t op_index) {
+    ops_ = std::make_shared<std::vector<CowOperationV3>>();
+    ops_->resize(op_index);
+
+    // read beginning of operation buffer -> so op_index = 0
+    const off_t offset = GetOpOffset(0, header_);
+    if (!android::base::ReadFullyAtOffset(fd, ops_->data(), ops_->size() * sizeof(CowOperationV3),
+                                          offset)) {
+        PLOG(ERROR) << "read ops failed";
+        return false;
+    }
+
+    // fill out mapping of XOR op data location
+    uint64_t data_pos = GetDataOffset(header_);
+
+    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.
+
+    ops_->shrink_to_fit();
+
+    return true;
+}
+
+bool CowParserV3::Translate(TranslatedCowOps* out) {
+    out->ops = ops_;
+    out->header = header_;
+    return true;
+}
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h
new file mode 100644
index 0000000..afc01af
--- /dev/null
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/parser_v3.h
@@ -0,0 +1,60 @@
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// Copyright (C) 2023 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+#pragma once
+
+#include <stdint.h>
+
+#include <memory>
+#include <optional>
+#include <unordered_map>
+#include <vector>
+
+#include <android-base/unique_fd.h>
+#include <libsnapshot/cow_format.h>
+#include <libsnapshot_cow/parser_base.h>
+
+namespace android {
+namespace snapshot {
+
+class CowParserV3 final : public CowParserBase {
+  public:
+    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::vector<ResumePoint>> resume_points() const { return resume_points_; }
+
+  private:
+    bool ParseOps(android::base::borrowed_fd fd, const uint32_t op_index);
+    std::optional<uint32_t> FindResumeOp(const uint64_t label);
+    CowHeaderV3 header_ = {};
+    std::shared_ptr<std::vector<CowOperationV3>> ops_;
+    bool ReadResumeBuffer(android::base::borrowed_fd fd);
+    std::shared_ptr<std::vector<ResumePoint>> resume_points_;
+};
+
+}  // namespace snapshot
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/test_v2.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/test_v2.cpp
index 35d74ba..2709059 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/test_v2.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/test_v2.cpp
@@ -1522,6 +1522,37 @@
     ASSERT_TRUE(reader.GetFooter(&footer));
 }
 
+TEST_F(CowTest, DecompressIncompressibleBlock) {
+    auto fd = OpenTestFile("incompressible_block", O_RDONLY);
+    ASSERT_GE(fd, 0);
+
+    std::string original;
+    ASSERT_TRUE(android::base::ReadFdToString(fd, &original)) << strerror(errno);
+    ASSERT_EQ(original.size(), 4096);
+
+    CowOptions options;
+    options.compression = "gz";
+    auto writer = CreateCowWriter(2, options, GetCowFd());
+    ASSERT_NE(writer, nullptr);
+    ASSERT_TRUE(writer->AddRawBlocks(0, original.data(), original.size()));
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+    ASSERT_FALSE(iter->AtEnd());
+
+    std::string block(original.size(), '\0');
+    ASSERT_EQ(iter->Get()->data_length, 4096);
+    ASSERT_TRUE(ReadData(reader, iter->Get(), block.data(), block.size()));
+
+    for (size_t i = 0; i < block.size(); i++) {
+        ASSERT_EQ(block[i], original[i]) << "mismatch at byte " << i;
+    }
+}
+
 }  // namespace snapshot
 }  // namespace android
 
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp
index cc8dd83..c41e07c 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/test_v3.cpp
@@ -37,7 +37,7 @@
 namespace android {
 namespace snapshot {
 
-class CowOperationV3Test : public ::testing::Test {
+class CowTestV3 : public ::testing::Test {
   protected:
     virtual void SetUp() override {
         cow_ = std::make_unique<TemporaryFile>();
@@ -51,7 +51,12 @@
     std::unique_ptr<TemporaryFile> cow_;
 };
 
-TEST_F(CowOperationV3Test, CowHeaderV2Test) {
+// Helper to check read sizes.
+static inline bool ReadData(CowReader& reader, const CowOperation* op, void* buffer, size_t size) {
+    return reader.ReadData(op, buffer, size) == size;
+}
+
+TEST_F(CowTestV3, CowHeaderV2Test) {
     CowOptions options;
     options.cluster_ops = 5;
     options.num_merge_ops = 1;
@@ -67,11 +72,415 @@
 
     const auto& header = reader.GetHeader();
     ASSERT_EQ(header.prefix.magic, kCowMagicNumber);
-    ASSERT_EQ(header.prefix.major_version, kCowVersionMajor);
-    ASSERT_EQ(header.prefix.minor_version, kCowVersionMinor);
+    ASSERT_EQ(header.prefix.major_version, 2);
+    ASSERT_EQ(header.prefix.minor_version, 0);
     ASSERT_EQ(header.block_size, options.block_size);
     ASSERT_EQ(header.cluster_ops, options.cluster_ops);
 }
 
+TEST_F(CowTestV3, Header) {
+    CowOptions options;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    const auto& header = reader.GetHeader();
+    ASSERT_EQ(header.prefix.magic, kCowMagicNumber);
+    ASSERT_EQ(header.prefix.major_version, 3);
+    ASSERT_EQ(header.prefix.minor_version, 0);
+    ASSERT_EQ(header.block_size, options.block_size);
+    ASSERT_EQ(header.cluster_ops, 0);
+}
+
+TEST_F(CowTestV3, MaxOp) {
+    CowOptions options;
+    options.op_count_max = 20;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+    ASSERT_FALSE(writer->AddZeroBlocks(1, 21));
+    ASSERT_FALSE(writer->AddZeroBlocks(1, 1));
+    std::string data = "This is some data, believe it";
+    data.resize(options.block_size, '\0');
+
+    ASSERT_FALSE(writer->AddRawBlocks(5, data.data(), data.size()));
+
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+    ASSERT_EQ(reader.header_v3().op_count, 20);
+}
+
+TEST_F(CowTestV3, ZeroOp) {
+    CowOptions options;
+    options.op_count_max = 20;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+    ASSERT_TRUE(writer->AddZeroBlocks(1, 2));
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+    ASSERT_EQ(reader.header_v3().op_count, 2);
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+    ASSERT_FALSE(iter->AtEnd());
+
+    auto op = iter->Get();
+    ASSERT_EQ(op->type, kCowZeroOp);
+    ASSERT_EQ(op->data_length, 0);
+    ASSERT_EQ(op->new_block, 1);
+    ASSERT_EQ(op->source_info, 0);
+
+    iter->Next();
+    ASSERT_FALSE(iter->AtEnd());
+    op = iter->Get();
+
+    ASSERT_EQ(op->type, kCowZeroOp);
+    ASSERT_EQ(op->data_length, 0);
+    ASSERT_EQ(op->new_block, 2);
+    ASSERT_EQ(op->source_info, 0);
+}
+
+TEST_F(CowTestV3, ReplaceOp) {
+    CowOptions options;
+    options.op_count_max = 20;
+    options.scratch_space = false;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+    std::string data = "This is some data, believe it";
+    data.resize(options.block_size, '\0');
+
+    ASSERT_TRUE(writer->AddRawBlocks(5, data.data(), data.size()));
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    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);
+    ASSERT_EQ(header.block_size, options.block_size);
+    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, kCowReplaceOp);
+    ASSERT_EQ(op->data_length, 4096);
+    ASSERT_EQ(op->new_block, 5);
+    ASSERT_TRUE(ReadData(reader, op, sink.data(), sink.size()));
+    ASSERT_EQ(sink, data);
+}
+
+TEST_F(CowTestV3, ConsecutiveReplaceOp) {
+    CowOptions options;
+    options.op_count_max = 20;
+    options.scratch_space = false;
+    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->AddRawBlocks(5, data.data(), data.size()));
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    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);
+    ASSERT_EQ(header.block_size, options.block_size);
+    ASSERT_EQ(header.op_count, 5);
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+    ASSERT_FALSE(iter->AtEnd());
+
+    size_t i = 0;
+    std::string sink(data.size(), '\0');
+
+    while (!iter->AtEnd()) {
+        auto op = iter->Get();
+        ASSERT_EQ(op->type, kCowReplaceOp);
+        ASSERT_EQ(op->data_length, options.block_size);
+        ASSERT_EQ(op->new_block, 5 + i);
+        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);
+}
+
+TEST_F(CowTestV3, CopyOp) {
+    CowOptions options;
+    options.op_count_max = 100;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+
+    ASSERT_TRUE(writer->AddCopy(10, 1000, 100));
+    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.prefix.magic, kCowMagicNumber);
+    ASSERT_EQ(header.prefix.major_version, 3);
+    ASSERT_EQ(header.prefix.minor_version, kCowVersionMinor);
+    ASSERT_EQ(header.block_size, options.block_size);
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+    ASSERT_FALSE(iter->AtEnd());
+
+    size_t i = 0;
+    while (!iter->AtEnd()) {
+        auto op = iter->Get();
+        ASSERT_EQ(op->type, kCowCopyOp);
+        ASSERT_EQ(op->data_length, 0);
+        ASSERT_EQ(op->new_block, 10 + i);
+        ASSERT_EQ(GetCowOpSourceInfoData(*op), 1000 + i);
+        iter->Next();
+        i += 1;
+    }
+
+    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);
+}
+
+TEST_F(CowTestV3, AllOpsWithCompression) {
+    CowOptions options;
+    options.compression = "gz";
+    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() % 4);
+    }
+
+    ASSERT_TRUE(writer->AddZeroBlocks(10, 5));
+    ASSERT_TRUE(writer->AddCopy(15, 3, 5));
+    ASSERT_TRUE(writer->AddRawBlocks(18, data.data(), data.size()));
+    ASSERT_TRUE(writer->AddXorBlocks(50, data.data(), data.size(), 24, 10));
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    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);
+    ASSERT_EQ(header.block_size, options.block_size);
+    ASSERT_EQ(header.buffer_size, BUFFER_REGION_DEFAULT_SIZE);
+    ASSERT_EQ(header.op_count, 20);
+    ASSERT_EQ(header.op_count_max, 100);
+
+    auto iter = reader.GetOpIter();
+    ASSERT_NE(iter, nullptr);
+    ASSERT_FALSE(iter->AtEnd());
+
+    size_t i = 0;
+
+    while (i < 5) {
+        auto op = iter->Get();
+        ASSERT_EQ(op->type, kCowZeroOp);
+        ASSERT_EQ(op->new_block, 10 + i);
+        iter->Next();
+        i++;
+    }
+    i = 0;
+    while (i < 5) {
+        auto op = iter->Get();
+        ASSERT_EQ(op->type, kCowCopyOp);
+        ASSERT_EQ(op->new_block, 15 + i);
+        ASSERT_EQ(GetCowOpSourceInfoData(*op), 3 + i);
+        iter->Next();
+        i++;
+    }
+    i = 0;
+    std::string sink(data.size(), '\0');
+
+    while (i < 5) {
+        auto op = iter->Get();
+        ASSERT_EQ(op->type, kCowReplaceOp);
+        ASSERT_EQ(op->new_block, 18 + i);
+        ASSERT_TRUE(
+                ReadData(reader, op, sink.data() + (i * options.block_size), options.block_size));
+        iter->Next();
+        i++;
+    }
+    ASSERT_EQ(sink, data);
+
+    i = 0;
+    std::fill(sink.begin(), sink.end(), '\0');
+    while (i < 5) {
+        auto op = iter->Get();
+        ASSERT_EQ(op->type, kCowXorOp);
+        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);
+}
+
+TEST_F(CowTestV3, GzCompression) {
+    CowOptions options;
+    options.op_count_max = 100;
+    options.compression = "gz";
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+
+    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->Finalize());
+
+    ASSERT_EQ(lseek(cow_->fd, 0, SEEK_SET), 0);
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    auto header = reader.header_v3();
+    ASSERT_EQ(header.compression_algorithm, kCowCompressGz);
+
+    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, kCowReplaceOp);
+    ASSERT_EQ(op->data_length, 56);  // compressed!
+    ASSERT_EQ(op->new_block, 50);
+    ASSERT_TRUE(ReadData(reader, op, sink.data(), sink.size()));
+    ASSERT_EQ(sink, data);
+
+    iter->Next();
+    ASSERT_TRUE(iter->AtEnd());
+}
+
+TEST_F(CowTestV3, ResumePointTest) {
+    CowOptions options;
+    options.op_count_max = 100;
+    auto writer = CreateCowWriter(3, options, GetCowFd());
+
+    ASSERT_TRUE(writer->AddZeroBlocks(0, 15));
+    ASSERT_TRUE(writer->AddLabel(0));
+    ASSERT_TRUE(writer->AddZeroBlocks(15, 15));
+    ASSERT_TRUE(writer->Finalize());
+
+    CowReader reader;
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+
+    auto header = reader.header_v3();
+    ASSERT_EQ(header.op_count, 30);
+
+    CowWriterV3 second_writer(options, GetCowFd());
+    ASSERT_TRUE(second_writer.Initialize(0));
+    ASSERT_TRUE(second_writer.Finalize());
+
+    ASSERT_TRUE(reader.Parse(cow_->fd));
+    header = reader.header_v3();
+    ASSERT_EQ(header.op_count, 15);
+}
 }  // namespace snapshot
-}  // namespace android
\ No newline at end of file
+}  // namespace android
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/writer_base.h b/fs_mgr/libsnapshot/libsnapshot_cow/writer_base.h
index 709b248..5274456 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/writer_base.h
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/writer_base.h
@@ -62,6 +62,8 @@
     bool InitFd();
     bool ValidateNewBlock(uint64_t new_block);
 
+    bool IsEstimating() const { return is_dev_null_; }
+
     CowOptions options_;
 
     android::base::unique_fd fd_;
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
index 83a9b1b..37324c7 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v2.cpp
@@ -273,10 +273,11 @@
     if (!ReadCowHeader(fd_, &header_v3)) {
         return false;
     }
+
     header_ = header_v3;
 
     CowParserV2 parser;
-    if (!parser.Parse(fd_, header_, {label})) {
+    if (!parser.Parse(fd_, header_v3, {label})) {
         return false;
     }
     if (header_.prefix.major_version > 2) {
@@ -292,7 +293,7 @@
     footer_.op.num_ops = 0;
     InitPos();
 
-    for (const auto& op : *parser.ops()) {
+    for (const auto& op : *parser.get_v2ops()) {
         AddOperation(op);
     }
 
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp
index 5ae5f19..6883c5e 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.cpp
@@ -34,6 +34,7 @@
 #include <zlib.h>
 
 #include <fcntl.h>
+#include <libsnapshot_cow/parser_v3.h>
 #include <linux/fs.h>
 #include <sys/ioctl.h>
 #include <unistd.h>
@@ -77,8 +78,10 @@
     // WIP: not quite sure how some of these are calculated yet, assuming buffer_size is determined
     // during COW size estimation
     header_.sequence_buffer_offset = 0;
-    header_.resume_buffer_size = 0;
-    header_.op_buffer_size = 0;
+    header_.resume_point_count = 0;
+    header_.resume_point_max = kNumResumePoints;
+    header_.op_count = 0;
+    header_.op_count_max = 0;
     header_.compression_algorithm = kCowCompressNone;
     return;
 }
@@ -96,6 +99,8 @@
         LOG(ERROR) << "unrecognized compression: " << options_.compression;
         return false;
     }
+    header_.compression_algorithm = *algorithm;
+
     if (parts.size() > 1) {
         if (!android::base::ParseUint(parts[1], &compression_.compression_level)) {
             LOG(ERROR) << "failed to parse compression level invalid type: " << parts[1];
@@ -107,6 +112,7 @@
     }
 
     compression_.algorithm = *algorithm;
+    compressor_ = ICompressor::Create(compression_, header_.block_size);
     return true;
 }
 
@@ -116,11 +122,14 @@
     if (!InitFd() || !ParseOptions()) {
         return false;
     }
-
-    CHECK(!label.has_value());
-
-    if (!OpenForWrite()) {
-        return false;
+    if (!label) {
+        if (!OpenForWrite()) {
+            return false;
+        }
+    } else {
+        if (!OpenForAppend(*label)) {
+            return false;
+        }
     }
 
     return true;
@@ -154,48 +163,155 @@
             return false;
         }
     }
+    header_.op_count_max = options_.op_count_max;
+    resume_points_ = std::make_shared<std::vector<ResumePoint>>();
 
     if (!Sync()) {
         LOG(ERROR) << "Header sync failed";
         return false;
     }
+    next_data_pos_ = GetDataOffset(header_);
+    return true;
+}
 
-    next_op_pos_ = 0;
-    next_data_pos_ = 0;
+bool CowWriterV3::OpenForAppend(uint64_t label) {
+    CowHeaderV3 header_v3;
+    if (!ReadCowHeader(fd_, &header_v3)) {
+        LOG(ERROR) << "Couldn't read Cow Header";
+        return false;
+    }
+
+    header_ = header_v3;
+
+    CHECK(label >= 0);
+    CowParserV3 parser;
+    if (!parser.Parse(fd_, header_, label)) {
+        PLOG(ERROR) << "unable to parse with given label: " << label;
+        return false;
+    }
+
+    resume_points_ = parser.resume_points();
+    options_.block_size = header_.block_size;
+    next_data_pos_ = GetDataOffset(header_);
+
+    TranslatedCowOps ops;
+    parser.Translate(&ops);
+    header_.op_count = ops.ops->size();
+
+    for (const auto& op : *ops.ops) {
+        next_data_pos_ += op.data_length;
+    }
 
     return true;
 }
 
 bool CowWriterV3::EmitCopy(uint64_t new_block, uint64_t old_block, uint64_t num_blocks) {
-    LOG(ERROR) << __LINE__ << " " << __FILE__ << " <- function here should never be called";
-    if (new_block || old_block || num_blocks) return false;
-    return false;
+    for (size_t i = 0; i < num_blocks; i++) {
+        CowOperationV3 op = {};
+        op.type = kCowCopyOp;
+        op.new_block = new_block + i;
+        op.source_info = old_block + i;
+        if (!WriteOperation(op)) {
+            return false;
+        }
+    }
+
+    return true;
 }
 
 bool CowWriterV3::EmitRawBlocks(uint64_t new_block_start, const void* data, size_t size) {
-    LOG(ERROR) << __LINE__ << " " << __FILE__ << " <- function here should never be called";
-
-    if (new_block_start || data || size) return false;
-    return false;
+    return EmitBlocks(new_block_start, data, size, 0, 0, kCowReplaceOp);
 }
 
 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 size_t num_blocks = (size / header_.block_size);
+    for (size_t i = 0; i < num_blocks; i++) {
+        const uint8_t* const iter =
+                reinterpret_cast<const uint8_t*>(data) + (header_.block_size * i);
+
+        CowOperation op = {};
+        op.new_block = new_block_start + i;
+
+        op.type = type;
+        if (type == kCowXorOp) {
+            op.source_info = (old_block + i) * header_.block_size + offset;
+        } else {
+            op.source_info = next_data_pos_;
+        }
+        std::basic_string<uint8_t> compressed_data;
+        const void* out_data = iter;
+
+        op.data_length = header_.block_size;
+
+        if (compression_.algorithm) {
+            if (!compressor_) {
+                PLOG(ERROR) << "Compressor not initialized";
+                return false;
+            }
+            compressed_data = compressor_->Compress(out_data, header_.block_size);
+            if (compressed_data.size() < op.data_length) {
+                out_data = compressed_data.data();
+                op.data_length = compressed_data.size();
+            }
+        }
+        if (!WriteOperation(op, out_data, op.data_length)) {
+            PLOG(ERROR) << "AddRawBlocks with compression: write failed. new block: "
+                        << new_block_start << " compression: " << compression_.algorithm;
+            return false;
+        }
+    }
+
+    return true;
 }
 
 bool CowWriterV3::EmitZeroBlocks(uint64_t new_block_start, uint64_t num_blocks) {
-    LOG(ERROR) << __LINE__ << " " << __FILE__ << " <- function here should never be called";
-    if (new_block_start && num_blocks) return false;
-    return false;
+    for (uint64_t i = 0; i < num_blocks; i++) {
+        CowOperationV3 op;
+        op.type = kCowZeroOp;
+        op.data_length = 0;
+        op.new_block = new_block_start + i;
+        op.source_info = 0;
+        if (!WriteOperation(op)) {
+            return false;
+        }
+    }
+    return true;
 }
 
 bool CowWriterV3::EmitLabel(uint64_t label) {
-    LOG(ERROR) << __LINE__ << " " << __FILE__ << " <- function here should never be called";
-    if (label) return false;
-    return false;
+    // remove all labels greater than this current one. we want to avoid the situation of adding
+    // in
+    // duplicate labels with differing op values
+    auto remove_if_callback = [&](const auto& resume_point) -> bool {
+        if (resume_point.label >= label) return true;
+        return false;
+    };
+    resume_points_->erase(
+            std::remove_if(resume_points_->begin(), resume_points_->end(), remove_if_callback),
+            resume_points_->end());
+
+    resume_points_->push_back({label, header_.op_count});
+    header_.resume_point_count++;
+    // remove the oldest resume point if resume_buffer is full
+    while (resume_points_->size() > header_.resume_point_max) {
+        resume_points_->erase(resume_points_->begin());
+    }
+
+    CHECK_LE(resume_points_->size(), header_.resume_point_max);
+
+    if (!android::base::WriteFullyAtOffset(fd_, resume_points_->data(),
+                                           resume_points_->size() * sizeof(ResumePoint),
+                                           GetResumeOffset(header_))) {
+        PLOG(ERROR) << "writing resume buffer failed";
+        return false;
+    }
+    return Sync();
 }
 
 bool CowWriterV3::EmitSequenceData(size_t num_ops, const uint32_t* data) {
@@ -204,15 +320,49 @@
     return false;
 }
 
+bool CowWriterV3::WriteOperation(const CowOperationV3& op, const void* data, size_t size) {
+    if (IsEstimating()) {
+        header_.op_count++;
+        header_.op_count_max++;
+        next_data_pos_ += op.data_length;
+        return true;
+    }
+
+    if (header_.op_count + 1 > header_.op_count_max) {
+        LOG(ERROR) << "Maximum number of ops reached: " << header_.op_count_max;
+        return false;
+    }
+
+    const off_t offset = GetOpOffset(header_.op_count, header_);
+    if (!android::base::WriteFullyAtOffset(fd_, &op, sizeof(op), offset)) {
+        PLOG(ERROR) << "write failed for " << op << " at " << offset;
+        return false;
+    }
+    if (data && size > 0) {
+        if (!android::base::WriteFullyAtOffset(fd_, data, size, next_data_pos_)) {
+            PLOG(ERROR) << "write failed for data of size: " << size
+                        << " at offset: " << next_data_pos_;
+            return false;
+        }
+    }
+    header_.op_count++;
+    next_data_pos_ += op.data_length;
+    next_op_pos_ += sizeof(CowOperationV3);
+
+    return true;
+}
+
 bool CowWriterV3::Finalize() {
-    LOG(ERROR) << __LINE__ << " " << __FILE__ << " <- function here should never be called";
-    return false;
+    CHECK_GE(header_.prefix.header_size, sizeof(CowHeaderV3));
+    CHECK_LE(header_.prefix.header_size, sizeof(header_));
+    if (!android::base::WriteFullyAtOffset(fd_, &header_, header_.prefix.header_size, 0)) {
+        return false;
+    }
+    return Sync();
 }
 
 uint64_t CowWriterV3::GetCowSize() {
-    LOG(ERROR) << __LINE__ << " " << __FILE__
-               << " <- Get Cow Size function here should never be called";
-    return 0;
+    return next_data_pos_;
 }
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.h b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.h
index 2a88a12..3dfc33c 100644
--- a/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.h
+++ b/fs_mgr/libsnapshot/libsnapshot_cow/writer_v3.h
@@ -14,7 +14,8 @@
 
 #pragma once
 
-#include <future>
+#include <android-base/logging.h>
+
 #include "writer_base.h"
 
 namespace android {
@@ -42,16 +43,28 @@
     void SetupHeaders();
     bool ParseOptions();
     bool OpenForWrite();
+    bool OpenForAppend(uint64_t label);
+    bool WriteOperation(const CowOperationV3& op, const void* data = nullptr, size_t size = 0);
+    bool EmitBlocks(uint64_t new_block_start, const void* data, size_t size, uint64_t old_block,
+                    uint16_t offset, uint8_t type);
+    bool CompressBlocks(size_t num_blocks, const void* data);
 
   private:
     CowHeaderV3 header_{};
     CowCompression compression_;
     // in the case that we are using one thread for compression, we can store and re-use the same
     // compressor
+    std::unique_ptr<ICompressor> compressor_;
+    std::vector<std::unique_ptr<CompressWorker>> compress_threads_;
+    // Resume points contain a laebl + cow_op_index.
+    std::shared_ptr<std::vector<ResumePoint>> resume_points_;
 
     uint64_t next_op_pos_ = 0;
     uint64_t next_data_pos_ = 0;
+    std::vector<std::basic_string<uint8_t>> compressed_buf_;
 
+    // in the case that we are using one thread for compression, we can store and re-use the same
+    // compressor
     int num_compress_threads_ = 1;
 };
 
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index eb4beb7..e91e3b7 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -3513,6 +3513,11 @@
             return Return::Error();
         }
 
+        if (!android::fs_mgr::WaitForFile(cow_path, 6s)) {
+            LOG(ERROR) << "Timed out waiting for device to appear: " << cow_path;
+            return Return::Error();
+        }
+
         if (it->second.using_snapuserd()) {
             unique_fd fd(open(cow_path.c_str(), O_RDWR | O_CLOEXEC));
             if (fd < 0) {
@@ -4334,32 +4339,30 @@
 }
 
 bool SnapshotManager::IsUserspaceSnapshotUpdateInProgress() {
-    auto slot = GetCurrentSlot();
-    if (slot == Slot::Target) {
-        // Merge in-progress
-        if (IsSnapuserdRequired()) {
+    // We cannot grab /metadata/ota lock here as this
+    // is in reboot path. See b/308900853
+    //
+    // Check if any of the partitions are mounted
+    // off dm-user block device. If so, then we are certain
+    // that OTA update in progress.
+    auto current_suffix = device_->GetSlotSuffix();
+    auto& dm = DeviceMapper::Instance();
+    auto dm_block_devices = dm.FindDmPartitions();
+    if (dm_block_devices.empty()) {
+        LOG(ERROR) << "No dm-enabled block device is found.";
+        return false;
+    }
+    for (auto& partition : dm_block_devices) {
+        std::string partition_name = partition.first + current_suffix;
+        DeviceMapper::TargetInfo snap_target;
+        if (!GetSingleTarget(partition_name, TableQuery::Status, &snap_target)) {
+            return false;
+        }
+        auto type = DeviceMapper::GetTargetType(snap_target.spec);
+        if (type == "user") {
             return true;
         }
     }
-
-    // Let's check more deeper to see if snapshots are mounted
-    auto lock = LockExclusive();
-    if (!lock) {
-        return false;
-    }
-
-    std::vector<std::string> snapshots;
-    if (!ListSnapshots(lock.get(), &snapshots)) {
-        return false;
-    }
-
-    for (const auto& snapshot : snapshots) {
-        // Active snapshot and daemon is alive
-        if (IsSnapshotDevice(snapshot) && EnsureSnapuserdConnected(2s)) {
-            return true;
-        }
-    }
-
     return false;
 }
 
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.cpp
index d979e20..ffd7a4b 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.cpp
@@ -51,11 +51,10 @@
 std::shared_ptr<HandlerThread> SnapshotHandlerManager::AddHandler(
         const std::string& misc_name, const std::string& cow_device_path,
         const std::string& backing_device, const std::string& base_path_merge,
-        std::shared_ptr<IBlockServerOpener> opener, int num_worker_threads, bool use_iouring,
-        bool perform_verification) {
+        std::shared_ptr<IBlockServerOpener> opener, int num_worker_threads, bool use_iouring) {
     auto snapuserd = std::make_shared<SnapshotHandler>(misc_name, cow_device_path, backing_device,
                                                        base_path_merge, opener, num_worker_threads,
-                                                       use_iouring, perform_verification);
+                                                       use_iouring, perform_verification_);
     if (!snapuserd->InitCowDevice()) {
         LOG(ERROR) << "Failed to initialize Snapuserd";
         return nullptr;
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.h b/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.h
index b1605f0..ff6ee8f 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.h
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/handler_manager.h
@@ -57,8 +57,7 @@
                                                       const std::string& backing_device,
                                                       const std::string& base_path_merge,
                                                       std::shared_ptr<IBlockServerOpener> opener,
-                                                      int num_worker_threads, bool use_iouring,
-                                                      bool perform_verification) = 0;
+                                                      int num_worker_threads, bool use_iouring) = 0;
 
     // Start serving requests on a snapshot handler.
     virtual bool StartHandler(const std::string& misc_name) = 0;
@@ -84,6 +83,9 @@
 
     // Returns whether all snapshots have verified.
     virtual bool GetVerificationStatus() = 0;
+
+    // Disable partition verification
+    virtual void DisableVerification() = 0;
 };
 
 class SnapshotHandlerManager final : public ISnapshotHandlerManager {
@@ -94,8 +96,7 @@
                                               const std::string& backing_device,
                                               const std::string& base_path_merge,
                                               std::shared_ptr<IBlockServerOpener> opener,
-                                              int num_worker_threads, bool use_iouring,
-                                              bool perform_verification) override;
+                                              int num_worker_threads, bool use_iouring) override;
     bool StartHandler(const std::string& misc_name) override;
     bool DeleteHandler(const std::string& misc_name) override;
     bool InitiateMerge(const std::string& misc_name) override;
@@ -104,6 +105,7 @@
     void TerminateMergeThreads() override;
     double GetMergePercentage() override;
     bool GetVerificationStatus() override;
+    void DisableVerification() override { perform_verification_ = false; }
 
   private:
     bool StartHandler(const std::shared_ptr<HandlerThread>& handler);
@@ -128,6 +130,7 @@
     int num_partitions_merge_complete_ = 0;
     std::queue<std::shared_ptr<HandlerThread>> merge_handlers_;
     android::base::unique_fd monitor_merge_event_fd_;
+    bool perform_verification_ = true;
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp
index 8208d67..950d771 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp
@@ -112,7 +112,7 @@
             return false;
         }
 
-        if (!android::base::WriteFully(cow_fd_, &header, sizeof(CowHeader))) {
+        if (!android::base::WriteFully(cow_fd_, &header, header.prefix.header_size)) {
             SNAP_PLOG(ERROR) << "Write to header failed";
             return false;
         }
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.cpp
index 13b9a00..6eee357 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.cpp
@@ -360,16 +360,15 @@
         num_worker_threads = 1;
     }
 
-    bool perform_verification = true;
-    if (android::base::EndsWith(misc_name, "-init") || is_socket_present_) {
-        perform_verification = false;
+    if (android::base::EndsWith(misc_name, "-init") || is_socket_present_ ||
+        (access(kBootSnapshotsWithoutSlotSwitch, F_OK) == 0)) {
+        handlers_->DisableVerification();
     }
 
     auto opener = block_server_factory_->CreateOpener(misc_name);
 
     return handlers_->AddHandler(misc_name, cow_device_path, backing_device, base_path_merge,
-                                 opener, num_worker_threads, io_uring_enabled_,
-                                 perform_verification);
+                                 opener, num_worker_threads, io_uring_enabled_);
 }
 
 bool UserSnapshotServer::WaitForSocket() {
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.h b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.h
index be28541..9926071 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.h
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.h
@@ -40,6 +40,8 @@
 
 static constexpr uint32_t kMaxPacketSize = 512;
 static constexpr uint8_t kMaxMergeThreads = 2;
+static constexpr char kBootSnapshotsWithoutSlotSwitch[] =
+        "/metadata/ota/snapshot-boot-without-slot-switch";
 
 class UserSnapshotServer {
   private:
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_test.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_test.cpp
index bed71cf..73c3cbf 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_test.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_test.cpp
@@ -627,9 +627,10 @@
 void SnapuserdTest::InitCowDevice() {
     auto factory = harness_->GetBlockServerFactory();
     auto opener = factory->CreateOpener(system_device_ctrl_name_);
+    handlers_->DisableVerification();
     auto handler =
             handlers_->AddHandler(system_device_ctrl_name_, cow_system_->path, base_dev_->GetPath(),
-                                  base_dev_->GetPath(), opener, 1, GetParam(), false);
+                                  base_dev_->GetPath(), opener, 1, GetParam());
     ASSERT_NE(handler, nullptr);
     ASSERT_NE(handler->snapuserd(), nullptr);
 #ifdef __ANDROID__
diff --git a/fs_mgr/libsnapshot/tools/testdata/incompressible_block b/fs_mgr/libsnapshot/tools/testdata/incompressible_block
new file mode 100644
index 0000000..cc45cd0
--- /dev/null
+++ b/fs_mgr/libsnapshot/tools/testdata/incompressible_block
Binary files differ
diff --git a/fs_mgr/tests/src/com/android/tests/vendoroverlay/VendorOverlayHostTest.java b/fs_mgr/tests/src/com/android/tests/vendoroverlay/VendorOverlayHostTest.java
index f08cab2..91f235c 100644
--- a/fs_mgr/tests/src/com/android/tests/vendoroverlay/VendorOverlayHostTest.java
+++ b/fs_mgr/tests/src/com/android/tests/vendoroverlay/VendorOverlayHostTest.java
@@ -21,10 +21,8 @@
 import com.android.tradefed.testtype.junit4.BaseHostJUnit4Test;
 import com.android.tradefed.util.CommandResult;
 import com.android.tradefed.util.CommandStatus;
-
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-
 import org.junit.After;
 import org.junit.Assert;
 import org.junit.Assume;
@@ -38,9 +36,15 @@
 @RunWith(DeviceJUnit4ClassRunner.class)
 public class VendorOverlayHostTest extends BaseHostJUnit4Test {
   boolean wasRoot = false;
+  String vndkVersion = null;
 
   @Before
   public void setup() throws DeviceNotAvailableException {
+    vndkVersion = getDevice().executeShellV2Command("getprop ro.vndk.version").getStdout();
+    Assume.assumeTrue(
+        "Vendor Overlay is disabled for VNDK deprecated devices",
+        vndkVersion != null && !vndkVersion.trim().isEmpty());
+
     wasRoot = getDevice().isAdbRoot();
     if (!wasRoot) {
       Assume.assumeTrue("Test requires root", getDevice().enableAdbRoot());
@@ -74,8 +78,6 @@
    */
   @Test
   public void testVendorOverlay() throws DeviceNotAvailableException {
-    String vndkVersion = getDevice().executeShellV2Command("getprop ro.vndk.version").getStdout();
-
     // Create files and modify policy
     CommandResult result = getDevice().executeShellV2Command(
         "echo '/(product|system/product)/vendor_overlay/" + vndkVersion +
diff --git a/init/host_init_verifier.cpp b/init/host_init_verifier.cpp
index f070776..662185c 100644
--- a/init/host_init_verifier.cpp
+++ b/init/host_init_verifier.cpp
@@ -108,9 +108,9 @@
     static passwd static_passwd = {
         .pw_name = static_name,
         .pw_dir = static_dir,
-        .pw_shell = static_shell,
         .pw_uid = 0,
         .pw_gid = 0,
+        .pw_shell = static_shell,
     };
 
     for (size_t n = 0; n < android_id_count; ++n) {
diff --git a/init/init.cpp b/init/init.cpp
index 40e2169..83cb78b 100644
--- a/init/init.cpp
+++ b/init/init.cpp
@@ -108,6 +108,7 @@
 using android::base::StringPrintf;
 using android::base::Timer;
 using android::base::Trim;
+using android::base::unique_fd;
 using android::fs_mgr::AvbHandle;
 using android::snapshot::SnapshotManager;
 
@@ -116,7 +117,8 @@
 
 static int property_triggers_enabled = 0;
 
-static int signal_fd = -1;
+int sigchld_fd = -1;
+static int sigterm_fd = -1;
 static int property_fd = -1;
 
 struct PendingControlMessage {
@@ -713,8 +715,9 @@
     HandlePowerctlMessage("shutdown,container");
 }
 
-static void HandleSignalFd() {
+static void HandleSignalFd(int signal) {
     signalfd_siginfo siginfo;
+    const int signal_fd = signal == SIGCHLD ? sigchld_fd : sigterm_fd;
     ssize_t bytes_read = TEMP_FAILURE_RETRY(read(signal_fd, &siginfo, sizeof(siginfo)));
     if (bytes_read != sizeof(siginfo)) {
         PLOG(ERROR) << "Failed to read siginfo from signal_fd";
@@ -748,10 +751,28 @@
     }
 }
 
+static Result<int> CreateAndRegisterSignalFd(Epoll* epoll, int signal) {
+    sigset_t mask;
+    sigemptyset(&mask);
+    sigaddset(&mask, signal);
+    unique_fd signal_fd(signalfd(-1, &mask, SFD_CLOEXEC));
+    if (signal_fd == -1) {
+        return ErrnoError() << "failed to create signalfd for signal " << signal;
+    }
+
+    auto result = epoll->RegisterHandler(
+            signal_fd.get(), [signal]() { HandleSignalFd(signal); }, EPOLLIN | EPOLLPRI);
+    if (!result.ok()) {
+        return result.error();
+    }
+
+    return signal_fd.release();
+}
+
 static void InstallSignalFdHandler(Epoll* epoll) {
     // Applying SA_NOCLDSTOP to a defaulted SIGCHLD handler prevents the signalfd from receiving
     // SIGCHLD when a child process stops or continues (b/77867680#comment9).
-    const struct sigaction act { .sa_handler = SIG_DFL, .sa_flags = SA_NOCLDSTOP };
+    const struct sigaction act { .sa_flags = SA_NOCLDSTOP, .sa_handler = SIG_DFL };
     sigaction(SIGCHLD, &act, nullptr);
 
     sigset_t mask;
@@ -774,14 +795,19 @@
         LOG(FATAL) << "Failed to register a fork handler: " << strerror(result);
     }
 
-    signal_fd = signalfd(-1, &mask, SFD_CLOEXEC);
-    if (signal_fd == -1) {
-        PLOG(FATAL) << "failed to create signalfd";
+    Result<int> cs_result = CreateAndRegisterSignalFd(epoll, SIGCHLD);
+    if (!cs_result.ok()) {
+        PLOG(FATAL) << cs_result.error();
     }
+    sigchld_fd = cs_result.value();
+    Service::SetSigchldFd(sigchld_fd);
 
-    constexpr int flags = EPOLLIN | EPOLLPRI;
-    if (auto result = epoll->RegisterHandler(signal_fd, HandleSignalFd, flags); !result.ok()) {
-        LOG(FATAL) << result.error();
+    if (sigismember(&mask, SIGTERM)) {
+        Result<int> cs_result = CreateAndRegisterSignalFd(epoll, SIGTERM);
+        if (!cs_result.ok()) {
+            PLOG(FATAL) << cs_result.error();
+        }
+        sigterm_fd = cs_result.value();
     }
 }
 
@@ -1059,8 +1085,8 @@
     am.QueueBuiltinAction(SetupCgroupsAction, "SetupCgroups");
     am.QueueBuiltinAction(SetKptrRestrictAction, "SetKptrRestrict");
     am.QueueBuiltinAction(TestPerfEventSelinuxAction, "TestPerfEventSelinux");
-    am.QueueBuiltinAction(ConnectEarlyStageSnapuserdAction, "ConnectEarlyStageSnapuserd");
     am.QueueEventTrigger("early-init");
+    am.QueueBuiltinAction(ConnectEarlyStageSnapuserdAction, "ConnectEarlyStageSnapuserd");
 
     // Queue an action that waits for coldboot done so we know ueventd has set up all of /dev...
     am.QueueBuiltinAction(wait_for_coldboot_done_action, "wait_for_coldboot_done");
diff --git a/init/init.h b/init/init.h
index 9c7e918..b781167 100644
--- a/init/init.h
+++ b/init/init.h
@@ -28,6 +28,8 @@
 namespace android {
 namespace init {
 
+extern int sigchld_fd;
+
 Parser CreateParser(ActionManager& action_manager, ServiceList& service_list);
 Parser CreateApexConfigParser(ActionManager& action_manager, ServiceList& service_list);
 
diff --git a/init/persistent_properties.cpp b/init/persistent_properties.cpp
index e89244f..6f8a4de 100644
--- a/init/persistent_properties.cpp
+++ b/init/persistent_properties.cpp
@@ -46,6 +46,13 @@
 
 constexpr const char kLegacyPersistentPropertyDir[] = "/data/property";
 
+void AddPersistentProperty(const std::string& name, const std::string& value,
+                           PersistentProperties* persistent_properties) {
+    auto persistent_property_record = persistent_properties->add_properties();
+    persistent_property_record->set_name(name);
+    persistent_property_record->set_value(value);
+}
+
 Result<PersistentProperties> LoadLegacyPersistentProperties() {
     std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(kLegacyPersistentPropertyDir), closedir);
     if (!dir) {
@@ -146,13 +153,6 @@
 
 }  // namespace
 
-void AddPersistentProperty(const std::string& name, const std::string& value,
-                           PersistentProperties* persistent_properties) {
-    auto persistent_property_record = persistent_properties->add_properties();
-    persistent_property_record->set_name(name);
-    persistent_property_record->set_value(value);
-}
-
 Result<PersistentProperties> LoadPersistentPropertyFile() {
     auto file_contents = ReadPersistentPropertyFile();
     if (!file_contents.ok()) return file_contents.error();
@@ -266,8 +266,57 @@
         }
     }
 
-    return *persistent_properties;
+    // loop over to find all staged props
+    auto const staged_prefix = std::string_view("next_boot.");
+    auto staged_props = std::unordered_map<std::string, std::string>();
+    for (const auto& property_record : persistent_properties->properties()) {
+        auto const& prop_name = property_record.name();
+        auto const& prop_value = property_record.value();
+        if (StartsWith(prop_name, staged_prefix)) {
+            auto actual_prop_name = prop_name.substr(staged_prefix.size());
+            staged_props[actual_prop_name] = prop_value;
+        }
+    }
+
+    if (staged_props.empty()) {
+        return *persistent_properties;
+    }
+
+    // if has staging, apply staging and perserve the original prop order
+    PersistentProperties updated_persistent_properties;
+    for (const auto& property_record : persistent_properties->properties()) {
+        auto const& prop_name = property_record.name();
+        auto const& prop_value = property_record.value();
+
+        // don't include staged props anymore
+        if (StartsWith(prop_name, staged_prefix)) {
+            continue;
+        }
+
+        auto iter = staged_props.find(prop_name);
+        if (iter != staged_props.end()) {
+            AddPersistentProperty(prop_name, iter->second, &updated_persistent_properties);
+            staged_props.erase(iter);
+        } else {
+            AddPersistentProperty(prop_name, prop_value, &updated_persistent_properties);
+        }
+    }
+
+    // add any additional staged props
+    for (auto const& [prop_name, prop_value] : staged_props) {
+        AddPersistentProperty(prop_name, prop_value, &updated_persistent_properties);
+    }
+
+    // write current updated persist prop file
+    auto result = WritePersistentPropertyFile(updated_persistent_properties);
+    if (!result.ok()) {
+        LOG(ERROR) << "Could not store persistent property: " << result.error();
+    }
+
+    return updated_persistent_properties;
 }
 
+
+
 }  // namespace init
 }  // namespace android
diff --git a/init/persistent_properties.h b/init/persistent_properties.h
index 7e9d438..11083da 100644
--- a/init/persistent_properties.h
+++ b/init/persistent_properties.h
@@ -25,8 +25,6 @@
 namespace android {
 namespace init {
 
-void AddPersistentProperty(const std::string& name, const std::string& value,
-                           PersistentProperties* persistent_properties);
 PersistentProperties LoadPersistentProperties();
 void WritePersistentProperty(const std::string& name, const std::string& value);
 PersistentProperties LoadPersistentPropertiesFromMemory();
diff --git a/init/persistent_properties_test.cpp b/init/persistent_properties_test.cpp
index e5d26db..5763050 100644
--- a/init/persistent_properties_test.cpp
+++ b/init/persistent_properties_test.cpp
@@ -178,5 +178,37 @@
     EXPECT_FALSE(it == read_back_properties.properties().end());
 }
 
+TEST(persistent_properties, StagedPersistProperty) {
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+    persistent_property_filename = tf.path;
+
+    std::vector<std::pair<std::string, std::string>> persistent_properties = {
+        {"persist.sys.locale", "en-US"},
+        {"next_boot.persist.test.numbers", "54321"},
+        {"persist.sys.timezone", "America/Los_Angeles"},
+        {"persist.test.numbers", "12345"},
+        {"next_boot.persist.test.extra", "abc"},
+    };
+
+    ASSERT_RESULT_OK(
+            WritePersistentPropertyFile(VectorToPersistentProperties(persistent_properties)));
+
+    std::vector<std::pair<std::string, std::string>> expected_persistent_properties = {
+        {"persist.sys.locale", "en-US"},
+        {"persist.sys.timezone", "America/Los_Angeles"},
+        {"persist.test.numbers", "54321"},
+        {"persist.test.extra", "abc"},
+    };
+
+    // lock down that staged props are applied
+    auto first_read_back_properties = LoadPersistentProperties();
+    CheckPropertiesEqual(expected_persistent_properties, first_read_back_properties);
+
+    // lock down that other props are not overwritten
+    auto second_read_back_properties = LoadPersistentProperties();
+    CheckPropertiesEqual(expected_persistent_properties, second_read_back_properties);
+}
+
 }  // namespace init
 }  // namespace android
diff --git a/init/property_service.cpp b/init/property_service.cpp
index b08a904..bd74358 100644
--- a/init/property_service.cpp
+++ b/init/property_service.cpp
@@ -76,6 +76,10 @@
 #include "system/core/init/property_service.pb.h"
 #include "util.h"
 
+static constexpr char APPCOMPAT_OVERRIDE_PROP_FOLDERNAME[] =
+        "/dev/__properties__/appcompat_override";
+static constexpr char APPCOMPAT_OVERRIDE_PROP_TREE_FILE[] =
+        "/dev/__properties__/appcompat_override/property_info";
 using namespace std::literals;
 
 using android::base::ErrnoError;
@@ -1279,11 +1283,17 @@
         return;
     }
 
-    constexpr static const char kPropertyInfosPath[] = "/dev/__properties__/property_info";
-    if (!WriteStringToFile(serialized_contexts, kPropertyInfosPath, 0444, 0, 0, false)) {
+    if (!WriteStringToFile(serialized_contexts, PROP_TREE_FILE, 0444, 0, 0, false)) {
         PLOG(ERROR) << "Unable to write serialized property infos to file";
     }
-    selinux_android_restorecon(kPropertyInfosPath, 0);
+    selinux_android_restorecon(PROP_TREE_FILE, 0);
+
+    mkdir(APPCOMPAT_OVERRIDE_PROP_FOLDERNAME, S_IRWXU | S_IXGRP | S_IXOTH);
+    if (!WriteStringToFile(serialized_contexts, APPCOMPAT_OVERRIDE_PROP_TREE_FILE, 0444, 0, 0,
+                           false)) {
+        PLOG(ERROR) << "Unable to write vendor overrides to file";
+    }
+    selinux_android_restorecon(APPCOMPAT_OVERRIDE_PROP_TREE_FILE, 0);
 }
 
 static void ExportKernelBootProps() {
@@ -1396,33 +1406,12 @@
     switch (init_message.msg_case()) {
         case InitMessage::kLoadPersistentProperties: {
             load_override_properties();
-            // Read persistent properties after all default values have been loaded.
-            // Apply staged and persistent properties
-            bool has_staged_prop = false;
-            auto const staged_prefix = std::string_view("next_boot.");
 
             auto persistent_properties = LoadPersistentProperties();
             for (const auto& property_record : persistent_properties.properties()) {
                 auto const& prop_name = property_record.name();
                 auto const& prop_value = property_record.value();
-
-                if (StartsWith(prop_name, staged_prefix)) {
-                  has_staged_prop = true;
-                  auto actual_prop_name = prop_name.substr(staged_prefix.size());
-                  InitPropertySet(actual_prop_name, prop_value);
-                } else {
-                  InitPropertySet(prop_name, prop_value);
-                }
-            }
-
-            // Update persist prop file if there are staged props
-            if (has_staged_prop) {
-                PersistentProperties props = LoadPersistentPropertiesFromMemory();
-                // write current updated persist prop file
-                auto result = WritePersistentPropertyFile(props);
-                if (!result.ok()) {
-                    LOG(ERROR) << "Could not store persistent property: " << result.error();
-                }
+                InitPropertySet(prop_name, prop_value);
             }
 
             // Apply debug ramdisk special settings after persistent properties are loaded.
diff --git a/init/reboot.cpp b/init/reboot.cpp
index 3351c4c..5757922 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -563,7 +563,7 @@
         }
     }
     if (timeout > 0ms) {
-        WaitToBeReaped(pids, timeout);
+        WaitToBeReaped(sigchld_fd, pids, timeout);
     } else {
         // Even if we don't to wait for services to stop, we still optimistically reap zombies.
         ReapAnyOutstandingChildren();
diff --git a/init/service.cpp b/init/service.cpp
index 5e900ee..d351a8f 100644
--- a/init/service.cpp
+++ b/init/service.cpp
@@ -136,6 +136,7 @@
 
 unsigned long Service::next_start_order_ = 1;
 bool Service::is_exec_service_running_ = false;
+int Service::sigchld_fd_ = -1;
 
 Service::Service(const std::string& name, Subcontext* subcontext_for_restart_commands,
                  const std::string& filename, const std::vector<std::string>& args)
@@ -194,28 +195,20 @@
     }
 }
 
-void Service::KillProcessGroup(int signal, bool report_oneshot) {
-    // If we've already seen a successful result from killProcessGroup*(), then we have removed
-    // the cgroup already and calling these functions a second time will simply result in an error.
-    // This is true regardless of which signal was sent.
-    // These functions handle their own logging, so no additional logging is needed.
-    if (!process_cgroup_empty_) {
+void Service::KillProcessGroup(int signal) {
+    // Always attempt the process kill if process is still running.
+    // Cgroup clean up routines are idempotent. It's safe to call
+    // killProcessGroup repeatedly. During shutdown, `init` will
+    // call this function to send SIGTERM/SIGKILL to all processes.
+    // These signals must be sent for a successful shutdown.
+    if (!process_cgroup_empty_ || IsRunning()) {
         LOG(INFO) << "Sending signal " << signal << " to service '" << name_ << "' (pid " << pid_
                   << ") process group...";
-        int max_processes = 0;
         int r;
         if (signal == SIGTERM) {
-            r = killProcessGroupOnce(uid(), pid_, signal, &max_processes);
+            r = killProcessGroupOnce(uid(), pid_, signal);
         } else {
-            r = killProcessGroup(uid(), pid_, signal, &max_processes);
-        }
-
-        if (report_oneshot && max_processes > 0) {
-            LOG(WARNING)
-                    << "Killed " << max_processes
-                    << " additional processes from a oneshot process group for service '" << name_
-                    << "'. This is new behavior, previously child processes would not be killed in "
-                       "this case.";
+            r = killProcessGroup(uid(), pid_, signal);
         }
 
         if (r == 0) process_cgroup_empty_ = true;
@@ -265,7 +258,7 @@
 
 void Service::Reap(const siginfo_t& siginfo) {
     if (!(flags_ & SVC_ONESHOT) || (flags_ & SVC_RESTART)) {
-        KillProcessGroup(SIGKILL, false);
+        KillProcessGroup(SIGKILL);
     } else {
         // Legacy behavior from ~2007 until Android R: this else branch did not exist and we did not
         // kill the process group in this case.
@@ -273,7 +266,7 @@
             // The new behavior in Android R is to kill these process groups in all cases.  The
             // 'true' parameter instructions KillProcessGroup() to report a warning message where it
             // detects a difference in behavior has occurred.
-            KillProcessGroup(SIGKILL, true);
+            KillProcessGroup(SIGKILL);
         }
     }
 
diff --git a/init/service.h b/init/service.h
index 9f09cef..13c8b5f 100644
--- a/init/service.h
+++ b/init/service.h
@@ -156,11 +156,12 @@
     const Subcontext* subcontext() const { return subcontext_; }
     const std::string& filename() const { return filename_; }
     void set_filename(const std::string& name) { filename_ = name; }
+    static void SetSigchldFd(int sigchld_fd) { sigchld_fd_ = sigchld_fd; }
 
   private:
     void NotifyStateChange(const std::string& new_state) const;
     void StopOrReset(int how);
-    void KillProcessGroup(int signal, bool report_oneshot = false);
+    void KillProcessGroup(int signal);
     void SetProcessAttributesAndCaps(InterprocessFifo setsid_finished);
     void ResetFlagsForStart();
     Result<void> CheckConsole();
@@ -168,8 +169,10 @@
     void RunService(const std::vector<Descriptor>& descriptors, InterprocessFifo cgroups_activated,
                     InterprocessFifo setsid_finished);
     void SetMountNamespace();
+
     static unsigned long next_start_order_;
     static bool is_exec_service_running_;
+    static int sigchld_fd_;
 
     const std::string name_;
     std::set<std::string> classnames_;
diff --git a/init/service_parser.cpp b/init/service_parser.cpp
index a1b2cc5..92e350b 100644
--- a/init/service_parser.cpp
+++ b/init/service_parser.cpp
@@ -179,8 +179,9 @@
     if (!ParseInt(args[1], &service_->proc_attr_.priority,
                   static_cast<int>(ANDROID_PRIORITY_HIGHEST),  // highest is negative
                   static_cast<int>(ANDROID_PRIORITY_LOWEST))) {
-        return Errorf("process priority value must be range {} - {}", ANDROID_PRIORITY_HIGHEST,
-                      ANDROID_PRIORITY_LOWEST);
+        return Errorf("process priority value must be range {} - {}",
+                      static_cast<int>(ANDROID_PRIORITY_HIGHEST),
+                      static_cast<int>(ANDROID_PRIORITY_LOWEST));
     }
     return {};
 }
diff --git a/init/sigchld_handler.cpp b/init/sigchld_handler.cpp
index f8c501f..9d4c7c8 100644
--- a/init/sigchld_handler.cpp
+++ b/init/sigchld_handler.cpp
@@ -18,6 +18,7 @@
 
 #include <signal.h>
 #include <string.h>
+#include <sys/signalfd.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -31,6 +32,7 @@
 
 #include <thread>
 
+#include "epoll.h"
 #include "init.h"
 #include "service.h"
 #include "service_list.h"
@@ -121,8 +123,23 @@
     }
 }
 
-void WaitToBeReaped(const std::vector<pid_t>& pids, std::chrono::milliseconds timeout) {
+static void DiscardSiginfo(int signal_fd) {
+    signalfd_siginfo siginfo;
+    ssize_t bytes_read = TEMP_FAILURE_RETRY(read(signal_fd, &siginfo, sizeof(siginfo)));
+    if (bytes_read != sizeof(siginfo)) {
+        LOG(WARNING) << "Unexpected: " << __func__ << " read " << bytes_read << " bytes instead of "
+                     << sizeof(siginfo);
+    }
+}
+
+void WaitToBeReaped(int sigchld_fd, const std::vector<pid_t>& pids,
+                    std::chrono::milliseconds timeout) {
     Timer t;
+    Epoll epoll;
+    // The init process passes a valid sigchld_fd argument but unit tests do not.
+    if (sigchld_fd >= 0) {
+        epoll.RegisterHandler(sigchld_fd, [sigchld_fd]() { DiscardSiginfo(sigchld_fd); });
+    }
     std::vector<pid_t> alive_pids(pids.begin(), pids.end());
     while (!alive_pids.empty() && t.duration() < timeout) {
         pid_t pid;
@@ -135,14 +152,18 @@
         if (alive_pids.empty()) {
             break;
         }
-        std::this_thread::sleep_for(50ms);
+        if (sigchld_fd >= 0) {
+            epoll.Wait(std::max(timeout - t.duration(), 0ms));
+        } else {
+            std::this_thread::sleep_for(50ms);
+        }
     }
     LOG(INFO) << "Waiting for " << pids.size() << " pids to be reaped took " << t << " with "
               << alive_pids.size() << " of them still running";
-    for (pid_t pid : pids) {
+    for (pid_t pid : alive_pids) {
         std::string status = "(no-such-pid)";
         ReadFileToString(StringPrintf("/proc/%d/status", pid), &status);
-        LOG(INFO) << "Still running: " << pid << ' ' << status;
+        LOG(INFO) << "Still running: " << pid << '\n' << status;
     }
 }
 
diff --git a/init/sigchld_handler.h b/init/sigchld_handler.h
index fac1020..e07a7d6 100644
--- a/init/sigchld_handler.h
+++ b/init/sigchld_handler.h
@@ -25,7 +25,8 @@
 
 void ReapAnyOutstandingChildren();
 
-void WaitToBeReaped(const std::vector<pid_t>& pids, std::chrono::milliseconds timeout);
+void WaitToBeReaped(int sigchld_fd, const std::vector<pid_t>& pids,
+                    std::chrono::milliseconds timeout);
 
 }  // namespace init
 }  // namespace android
diff --git a/libprocessgroup/include/processgroup/processgroup.h b/libprocessgroup/include/processgroup/processgroup.h
index dbaeb93..a319c63 100644
--- a/libprocessgroup/include/processgroup/processgroup.h
+++ b/libprocessgroup/include/processgroup/processgroup.h
@@ -26,7 +26,8 @@
 
 __BEGIN_DECLS
 
-static constexpr const char* CGROUPV2_CONTROLLER_NAME = "cgroup2";
+static constexpr const char* CGROUPV2_HIERARCHY_NAME = "cgroup2";
+[[deprecated]] static constexpr const char* CGROUPV2_CONTROLLER_NAME = "cgroup2";
 
 bool CgroupsAvailable();
 bool CgroupGetControllerPath(const std::string& cgroup_name, std::string* path);
@@ -67,14 +68,11 @@
 // Return 0 and removes the cgroup if there are no longer any processes in it.
 // Returns -1 in the case of an error occurring or if there are processes still running
 // even after retrying for up to 200ms.
-// If max_processes is not nullptr, it returns the maximum number of processes seen in the cgroup
-// during the killing process.  Note that this can be 0 if all processes from the process group have
-// already been terminated.
-int killProcessGroup(uid_t uid, int initialPid, int signal, int* max_processes = nullptr);
+int killProcessGroup(uid_t uid, int initialPid, int signal);
 
 // Returns the same as killProcessGroup(), however it does not retry, which means
 // that it only returns 0 in the case that the cgroup exists and it contains no processes.
-int killProcessGroupOnce(uid_t uid, int initialPid, int signal, int* max_processes = nullptr);
+int killProcessGroupOnce(uid_t uid, int initialPid, int signal);
 
 // Sends the provided signal to all members of a process group, but does not wait for processes to
 // exit, or for the cgroup to be removed. Callers should also ensure that killProcessGroup is called
diff --git a/libprocessgroup/processgroup.cpp b/libprocessgroup/processgroup.cpp
index cc2565f..d352f0e 100644
--- a/libprocessgroup/processgroup.cpp
+++ b/libprocessgroup/processgroup.cpp
@@ -129,7 +129,7 @@
     }
 
     if (!attr->GetPathForTask(tid, path)) {
-        PLOG(ERROR) << "Failed to find cgroup for tid " << tid;
+        LOG(ERROR) << "Failed to find cgroup for tid " << tid;
         return false;
     }
 
@@ -213,7 +213,7 @@
     return StringPrintf("%s/uid_%u/pid_%d", cgroup, uid, pid);
 }
 
-static int RemoveProcessGroup(const char* cgroup, uid_t uid, int pid, unsigned int retries) {
+static int RemoveCgroup(const char* cgroup, uid_t uid, int pid, unsigned int retries) {
     int ret = 0;
     auto uid_pid_path = ConvertUidPidToPath(cgroup, uid, pid);
 
@@ -233,7 +233,7 @@
     return ret;
 }
 
-static bool RemoveUidProcessGroups(const std::string& uid_path, bool empty_only) {
+static bool RemoveUidCgroups(const std::string& uid_path, bool empty_only) {
     std::unique_ptr<DIR, decltype(&closedir)> uid(opendir(uid_path.c_str()), closedir);
     bool empty = true;
     if (uid != NULL) {
@@ -275,11 +275,11 @@
     return empty;
 }
 
-void removeAllProcessGroupsInternal(bool empty_only) {
+static void removeAllProcessGroupsInternal(bool empty_only) {
     std::vector<std::string> cgroups;
     std::string path, memcg_apps_path;
 
-    if (CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &path)) {
+    if (CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &path)) {
         cgroups.push_back(path);
     }
     if (CgroupGetMemcgAppsPath(&memcg_apps_path) && memcg_apps_path != path) {
@@ -302,7 +302,7 @@
                 }
 
                 auto path = StringPrintf("%s/%s", cgroup_root_path.c_str(), dir->d_name);
-                if (!RemoveUidProcessGroups(path, empty_only)) {
+                if (!RemoveUidCgroups(path, empty_only)) {
                     LOG(VERBOSE) << "Skip removing " << path;
                     continue;
                 }
@@ -455,29 +455,21 @@
     return (!fd || feof(fd.get())) ? processes : -1;
 }
 
-static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries,
-                            int* max_processes) {
+static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries) {
     CHECK_GE(uid, 0);
     CHECK_GT(initialPid, 0);
 
     std::string hierarchy_root_path;
     if (CgroupsAvailable()) {
-        CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &hierarchy_root_path);
+        CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &hierarchy_root_path);
     }
     const char* cgroup = hierarchy_root_path.c_str();
 
     std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
 
-    if (max_processes != nullptr) {
-        *max_processes = 0;
-    }
-
     int retry = retries;
     int processes;
     while ((processes = DoKillProcessGroupOnce(cgroup, uid, initialPid, signal)) > 0) {
-        if (max_processes != nullptr && processes > *max_processes) {
-            *max_processes = processes;
-        }
         LOG(VERBOSE) << "Killed " << processes << " processes for processgroup " << initialPid;
         if (!CgroupsAvailable()) {
             // makes no sense to retry, because there are no cgroup_procs file
@@ -519,12 +511,12 @@
         }
 
         // 400 retries correspond to 2 secs max timeout
-        int err = RemoveProcessGroup(cgroup, uid, initialPid, 400);
+        int err = RemoveCgroup(cgroup, uid, initialPid, 400);
 
         if (isMemoryCgroupSupported() && UsePerAppMemcg()) {
             std::string memcg_apps_path;
             if (CgroupGetMemcgAppsPath(&memcg_apps_path) &&
-                RemoveProcessGroup(memcg_apps_path.c_str(), uid, initialPid, 400) < 0) {
+                RemoveCgroup(memcg_apps_path.c_str(), uid, initialPid, 400) < 0) {
                 return -1;
             }
         }
@@ -540,18 +532,18 @@
     }
 }
 
-int killProcessGroup(uid_t uid, int initialPid, int signal, int* max_processes) {
-    return KillProcessGroup(uid, initialPid, signal, 40 /*retries*/, max_processes);
+int killProcessGroup(uid_t uid, int initialPid, int signal) {
+    return KillProcessGroup(uid, initialPid, signal, 40 /*retries*/);
 }
 
-int killProcessGroupOnce(uid_t uid, int initialPid, int signal, int* max_processes) {
-    return KillProcessGroup(uid, initialPid, signal, 0 /*retries*/, max_processes);
+int killProcessGroupOnce(uid_t uid, int initialPid, int signal) {
+    return KillProcessGroup(uid, initialPid, signal, 0 /*retries*/);
 }
 
 int sendSignalToProcessGroup(uid_t uid, int initialPid, int signal) {
     std::string hierarchy_root_path;
     if (CgroupsAvailable()) {
-        CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &hierarchy_root_path);
+        CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &hierarchy_root_path);
     }
     const char* cgroup = hierarchy_root_path.c_str();
     return DoKillProcessGroupOnce(cgroup, uid, initialPid, signal);
@@ -609,7 +601,7 @@
     CHECK_GT(initialPid, 0);
 
     if (memControl && !UsePerAppMemcg()) {
-        PLOG(ERROR) << "service memory controls are used without per-process memory cgroup support";
+        LOG(ERROR) << "service memory controls are used without per-process memory cgroup support";
         return -EINVAL;
     }
 
@@ -625,19 +617,19 @@
     }
 
     std::string cgroup;
-    CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &cgroup);
+    CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, &cgroup);
     return createProcessGroupInternal(uid, initialPid, cgroup, true);
 }
 
 static bool SetProcessGroupValue(int tid, const std::string& attr_name, int64_t value) {
     if (!isMemoryCgroupSupported()) {
-        PLOG(ERROR) << "Memcg is not mounted.";
+        LOG(ERROR) << "Memcg is not mounted.";
         return false;
     }
 
     std::string path;
     if (!CgroupGetAttributePathForTask(attr_name, tid, &path)) {
-        PLOG(ERROR) << "Failed to find attribute '" << attr_name << "'";
+        LOG(ERROR) << "Failed to find attribute '" << attr_name << "'";
         return false;
     }
 
@@ -672,4 +664,4 @@
     }
 
     return tp->IsValidForProcess(uid, pid);
-}
\ No newline at end of file
+}
diff --git a/libprocessgroup/setup/cgroup_map_write.cpp b/libprocessgroup/setup/cgroup_map_write.cpp
index fbeedf9..4e44c91 100644
--- a/libprocessgroup/setup/cgroup_map_write.cpp
+++ b/libprocessgroup/setup/cgroup_map_write.cpp
@@ -212,7 +212,7 @@
     if (root.isMember("Cgroups2")) {
         const Json::Value& cgroups2 = root["Cgroups2"];
         std::string root_path = cgroups2["Path"].asString();
-        MergeCgroupToDescriptors(descriptors, cgroups2, CGROUPV2_CONTROLLER_NAME, "", 2);
+        MergeCgroupToDescriptors(descriptors, cgroups2, CGROUPV2_HIERARCHY_NAME, "", 2);
 
         const Json::Value& childGroups = cgroups2["Controllers"];
         for (Json::Value::ArrayIndex i = 0; i < childGroups.size(); ++i) {
@@ -358,7 +358,7 @@
     const format::CgroupController* controller = descriptor.controller();
 
     if (controller->version() == 2) {
-        if (!strcmp(controller->name(), CGROUPV2_CONTROLLER_NAME)) {
+        if (!strcmp(controller->name(), CGROUPV2_HIERARCHY_NAME)) {
             return MountV2CgroupController(descriptor);
         } else {
             return ActivateV2CgroupController(descriptor);
diff --git a/libprocessgroup/task_profiles_test.cpp b/libprocessgroup/task_profiles_test.cpp
index 99d819a..b17e695 100644
--- a/libprocessgroup/task_profiles_test.cpp
+++ b/libprocessgroup/task_profiles_test.cpp
@@ -116,7 +116,7 @@
     }
     bool GetPathForTask(int tid, std::string* path) const override {
 #ifdef __ANDROID__
-        CHECK(CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, path));
+        CHECK(CgroupGetControllerPath(CGROUPV2_HIERARCHY_NAME, path));
         CHECK_GT(path->length(), 0);
         if (path->rbegin()[0] != '/') {
             *path += "/";
diff --git a/libutils/binder/RefBase.cpp b/libutils/binder/RefBase.cpp
index 4b0cc16..2d2e40b 100644
--- a/libutils/binder/RefBase.cpp
+++ b/libutils/binder/RefBase.cpp
@@ -55,14 +55,16 @@
 // log all reference counting operations
 #define PRINT_REFS 0
 
+#if !defined(ANDROID_UTILS_CALLSTACK_ENABLED)
 #if defined(__linux__)
 // CallStack is only supported on linux type platforms.
-#define CALLSTACK_ENABLED 1
+#define ANDROID_UTILS_CALLSTACK_ENABLED 1
 #else
-#define CALLSTACK_ENABLED 0
-#endif
+#define ANDROID_UTILS_CALLSTACK_ENABLED 0
+#endif  // defined(__linux__)
+#endif  // !defined(ANDROID_UTILS_CALLSTACK_ENABLED)
 
-#if CALLSTACK_ENABLED
+#if ANDROID_UTILS_CALLSTACK_ENABLED
 #include "../../include/utils/CallStack.h"
 #endif
 
@@ -230,7 +232,7 @@
             while (refs) {
                 char inc = refs->ref >= 0 ? '+' : '-';
                 ALOGD("\t%c ID %p (ref %d):", inc, refs->id, refs->ref);
-#if DEBUG_REFS_CALLSTACK_ENABLED && CALLSTACK_ENABLED
+#if DEBUG_REFS_CALLSTACK_ENABLED && ANDROID_UTILS_CALLSTACK_ENABLED
                 CallStack::logStack(LOG_TAG, refs->stack.get());
 #endif
                 refs = refs->next;
@@ -244,7 +246,7 @@
             while (refs) {
                 char inc = refs->ref >= 0 ? '+' : '-';
                 ALOGD("\t%c ID %p (ref %d):", inc, refs->id, refs->ref);
-#if DEBUG_REFS_CALLSTACK_ENABLED && CALLSTACK_ENABLED
+#if DEBUG_REFS_CALLSTACK_ENABLED && ANDROID_UTILS_CALLSTACK_ENABLED
                 CallStack::logStack(LOG_TAG, refs->stack.get());
 #endif
                 refs = refs->next;
@@ -252,7 +254,7 @@
         }
         if (dumpStack) {
             ALOGE("above errors at:");
-#if CALLSTACK_ENABLED
+#if ANDROID_UTILS_CALLSTACK_ENABLED
             CallStack::logStack(LOG_TAG);
 #endif
         }
@@ -341,7 +343,7 @@
     {
         ref_entry* next;
         const void* id;
-#if DEBUG_REFS_CALLSTACK_ENABLED && CALLSTACK_ENABLED
+#if DEBUG_REFS_CALLSTACK_ENABLED && ANDROID_UTILS_CALLSTACK_ENABLED
         CallStack::CallStackUPtr stack;
 #endif
         int32_t ref;
@@ -358,7 +360,7 @@
             // decrement the reference count.
             ref->ref = mRef;
             ref->id = id;
-#if DEBUG_REFS_CALLSTACK_ENABLED && CALLSTACK_ENABLED
+#if DEBUG_REFS_CALLSTACK_ENABLED && ANDROID_UTILS_CALLSTACK_ENABLED
             ref->stack = CallStack::getCurrent(2);
 #endif
             ref->next = *refs;
@@ -394,7 +396,7 @@
                 ref = ref->next;
             }
 
-#if CALLSTACK_ENABLED
+#if ANDROID_UTILS_CALLSTACK_ENABLED
             CallStack::logStack(LOG_TAG);
 #endif
         }
@@ -422,7 +424,7 @@
             snprintf(buf, sizeof(buf), "\t%c ID %p (ref %d):\n",
                      inc, refs->id, refs->ref);
             out->append(buf);
-#if DEBUG_REFS_CALLSTACK_ENABLED && CALLSTACK_ENABLED
+#if DEBUG_REFS_CALLSTACK_ENABLED && ANDROID_UTILS_CALLSTACK_ENABLED
             out->append(CallStack::stackToString("\t\t", refs->stack.get()));
 #else
             out->append("\t\t(call stacks disabled)");
@@ -788,7 +790,7 @@
                   "object.",
                   mRefs->mWeak.load(), this);
 
-#if CALLSTACK_ENABLED
+#if ANDROID_UTILS_CALLSTACK_ENABLED
             CallStack::logStack(LOG_TAG);
 #endif
         } else if (strongs != 0) {
diff --git a/property_service/libpropertyinfoparser/include/property_info_parser/property_info_parser.h b/property_service/libpropertyinfoparser/include/property_info_parser/property_info_parser.h
index 0548021..65705ac 100644
--- a/property_service/libpropertyinfoparser/include/property_info_parser/property_info_parser.h
+++ b/property_service/libpropertyinfoparser/include/property_info_parser/property_info_parser.h
@@ -20,6 +20,8 @@
 #include <stdint.h>
 #include <stdlib.h>
 
+static constexpr char PROP_TREE_FILE[] = "/dev/__properties__/property_info";
+
 namespace android {
 namespace properties {
 
diff --git a/run-as/run-as.cpp b/run-as/run-as.cpp
index cc92c68..32057b4 100644
--- a/run-as/run-as.cpp
+++ b/run-as/run-as.cpp
@@ -76,9 +76,6 @@
     error(1, errno, "couldn't stat %s", path);
   }
 
-  // /data/user/0 is a known safe symlink.
-  if (strcmp("/data/user/0", path) == 0) return;
-
   // Must be a real directory, not a symlink.
   if (!S_ISDIR(st.st_mode)) {
     error(1, 0, "%s not a directory: %o", path, st.st_mode);
@@ -191,27 +188,17 @@
   }
 
   // Retrieve package information from system, switching egid so we can read the file.
+  pkg_info info = {.name = pkgname};
   gid_t old_egid = getegid();
   if (setegid(AID_PACKAGE_INFO) == -1) error(1, errno, "setegid(AID_PACKAGE_INFO) failed");
-  pkg_info info;
-  memset(&info, 0, sizeof(info));
-  info.name = pkgname;
   if (!packagelist_parse(packagelist_parse_callback, &info)) {
     error(1, errno, "packagelist_parse failed");
   }
-
-  // Handle a multi-user data path
-  if (userId > 0) {
-    free(info.data_dir);
-    if (asprintf(&info.data_dir, "/data/user/%d/%s", userId, pkgname) == -1) {
-      error(1, errno, "asprintf failed");
-    }
-  }
+  if (setegid(old_egid) == -1) error(1, errno, "couldn't restore egid");
 
   if (info.uid == 0) {
     error(1, 0, "unknown package: %s", pkgname);
   }
-  if (setegid(old_egid) == -1) error(1, errno, "couldn't restore egid");
 
   // Verify that user id is not too big.
   if ((UID_MAX - info.uid) / AID_USER_OFFSET < (uid_t)userId) {
@@ -231,6 +218,12 @@
     error(1, 0, "package not debuggable: %s", pkgname);
   }
 
+  // Ensure we have the right data path for the specific user.
+  free(info.data_dir);
+  if (asprintf(&info.data_dir, "/data/user/%d/%s", userId, pkgname) == -1) {
+    error(1, errno, "asprintf failed");
+  }
+
   // Check that the data directory path is valid.
   check_data_path(pkgname, info.data_dir, userAppId);