diff --git a/fs_mgr/libsnapshot/snapuserd/Android.bp b/fs_mgr/libsnapshot/snapuserd/Android.bp
index bc2bceb..d751fb8 100644
--- a/fs_mgr/libsnapshot/snapuserd/Android.bp
+++ b/fs_mgr/libsnapshot/snapuserd/Android.bp
@@ -47,6 +47,7 @@
         "libbase",
         "liblog",
     ],
+    export_include_dirs: ["include"],
     ramdisk_available: true,
 }
 
@@ -68,6 +69,7 @@
         "user-space-merge/snapuserd_readahead.cpp",
         "user-space-merge/snapuserd_transitions.cpp",
         "user-space-merge/snapuserd_server.cpp",
+        "user-space-merge/snapuserd_verify.cpp",
     ],
 
     cflags: [
@@ -88,6 +90,11 @@
         "libext4_utils",
         "liburing",
     ],
+
+    header_libs: [
+        "libstorage_literals_headers",
+    ],
+
     include_dirs: ["bionic/libc/kernel"],
 }
 
diff --git a/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_client.h b/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_client.h
index cebda1c..9a69d58 100644
--- a/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_client.h
+++ b/fs_mgr/libsnapshot/snapuserd/include/snapuserd/snapuserd_client.h
@@ -89,6 +89,10 @@
 
     // Return the status of the snapshot
     std::string QuerySnapshotStatus(const std::string& misc_name);
+
+    // Check the update verification status - invoked by update_verifier during
+    // boot
+    bool QueryUpdateVerification();
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/snapuserd/snapuserd_client.cpp b/fs_mgr/libsnapshot/snapuserd/snapuserd_client.cpp
index 7b1c7a3..e08cf9b 100644
--- a/fs_mgr/libsnapshot/snapuserd/snapuserd_client.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/snapuserd_client.cpp
@@ -269,5 +269,15 @@
     return Receivemsg();
 }
 
+bool SnapuserdClient::QueryUpdateVerification() {
+    std::string msg = "update-verify";
+    if (!Sendmsg(msg)) {
+        LOG(ERROR) << "Failed to send message " << msg << " to snapuserd";
+        return false;
+    }
+    std::string response = Receivemsg();
+    return response == "success";
+}
+
 }  // namespace snapshot
 }  // namespace android
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 718c13c..8939b78 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.cpp
@@ -18,6 +18,7 @@
 
 #include <sys/utsname.h>
 
+#include <android-base/chrono_utils.h>
 #include <android-base/properties.h>
 #include <android-base/scopeguard.h>
 #include <android-base/strings.h>
@@ -70,6 +71,9 @@
 
     read_ahead_thread_ = std::make_unique<ReadAhead>(cow_device_, backing_store_device_, misc_name_,
                                                      GetSharedPtr());
+
+    update_verify_ = std::make_unique<UpdateVerify>(misc_name_);
+
     return true;
 }
 
@@ -307,206 +311,6 @@
     return ReadMetadata();
 }
 
-void SnapshotHandler::FinalizeIouring() {
-    io_uring_queue_exit(ring_.get());
-}
-
-bool SnapshotHandler::InitializeIouring(int io_depth) {
-    ring_ = std::make_unique<struct io_uring>();
-
-    int ret = io_uring_queue_init(io_depth, ring_.get(), 0);
-    if (ret) {
-        LOG(ERROR) << "io_uring_queue_init failed with ret: " << ret;
-        return false;
-    }
-
-    LOG(INFO) << "io_uring_queue_init success with io_depth: " << io_depth;
-    return true;
-}
-
-bool SnapshotHandler::ReadBlocksAsync(const std::string& dm_block_device,
-                                      const std::string& partition_name, size_t size) {
-    // 64k block size with io_depth of 64 is optimal
-    // for a single thread. We just need a single thread
-    // to read all the blocks from all dynamic partitions.
-    size_t io_depth = 64;
-    size_t bs = (64 * 1024);
-
-    if (!InitializeIouring(io_depth)) {
-        return false;
-    }
-
-    LOG(INFO) << "ReadBlockAsync start "
-              << " Block-device: " << dm_block_device << " Partition-name: " << partition_name
-              << " Size: " << size;
-
-    auto scope_guard = android::base::make_scope_guard([this]() -> void { FinalizeIouring(); });
-
-    std::vector<std::unique_ptr<struct iovec>> vecs;
-    using AlignedBuf = std::unique_ptr<void, decltype(free)*>;
-    std::vector<AlignedBuf> alignedBufVector;
-
-    /*
-     * TODO: We need aligned memory for DIRECT-IO. However, if we do
-     * a DIRECT-IO and verify the blocks then we need to inform
-     * update-verifier that block verification has been done and
-     * there is no need to repeat the same. We are not there yet
-     * as we need to see if there are any boot time improvements doing
-     * a DIRECT-IO.
-     *
-     * Also, we could you the same function post merge for block verification;
-     * again, we can do a DIRECT-IO instead of thrashing page-cache and
-     * hurting other applications.
-     *
-     * For now, we will just create aligned buffers but rely on buffered
-     * I/O until we have perf numbers to justify DIRECT-IO.
-     */
-    for (int i = 0; i < io_depth; i++) {
-        auto iovec = std::make_unique<struct iovec>();
-        vecs.push_back(std::move(iovec));
-
-        struct iovec* iovec_ptr = vecs[i].get();
-
-        if (posix_memalign(&iovec_ptr->iov_base, BLOCK_SZ, bs)) {
-            LOG(ERROR) << "posix_memalign failed";
-            return false;
-        }
-
-        iovec_ptr->iov_len = bs;
-        alignedBufVector.push_back(
-                std::unique_ptr<void, decltype(free)*>(iovec_ptr->iov_base, free));
-    }
-
-    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
-    if (fd.get() == -1) {
-        SNAP_PLOG(ERROR) << "File open failed - block-device " << dm_block_device
-                         << " partition-name: " << partition_name;
-        return false;
-    }
-
-    loff_t offset = 0;
-    size_t remain = size;
-    size_t read_sz = io_depth * bs;
-
-    while (remain > 0) {
-        size_t to_read = std::min(remain, read_sz);
-        size_t queue_size = to_read / bs;
-
-        for (int i = 0; i < queue_size; i++) {
-            struct io_uring_sqe* sqe = io_uring_get_sqe(ring_.get());
-            if (!sqe) {
-                SNAP_LOG(ERROR) << "io_uring_get_sqe() failed";
-                return false;
-            }
-
-            struct iovec* iovec_ptr = vecs[i].get();
-
-            io_uring_prep_read(sqe, fd.get(), iovec_ptr->iov_base, iovec_ptr->iov_len, offset);
-            sqe->flags |= IOSQE_ASYNC;
-            offset += bs;
-        }
-
-        int ret = io_uring_submit(ring_.get());
-        if (ret != queue_size) {
-            SNAP_LOG(ERROR) << "submit got: " << ret << " wanted: " << queue_size;
-            return false;
-        }
-
-        for (int i = 0; i < queue_size; i++) {
-            struct io_uring_cqe* cqe;
-
-            int ret = io_uring_wait_cqe(ring_.get(), &cqe);
-            if (ret) {
-                SNAP_PLOG(ERROR) << "wait_cqe failed" << ret;
-                return false;
-            }
-
-            if (cqe->res < 0) {
-                SNAP_LOG(ERROR) << "io failed with res: " << cqe->res;
-                return false;
-            }
-            io_uring_cqe_seen(ring_.get(), cqe);
-        }
-
-        remain -= to_read;
-    }
-
-    LOG(INFO) << "ReadBlockAsync complete: "
-              << " Block-device: " << dm_block_device << " Partition-name: " << partition_name
-              << " Size: " << size;
-    return true;
-}
-
-void SnapshotHandler::ReadBlocksToCache(const std::string& dm_block_device,
-                                        const std::string& partition_name, off_t offset,
-                                        size_t size) {
-    android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
-    if (fd.get() == -1) {
-        SNAP_PLOG(ERROR) << "Error reading " << dm_block_device
-                         << " partition-name: " << partition_name;
-        return;
-    }
-
-    size_t remain = size;
-    off_t file_offset = offset;
-    // We pick 4M I/O size based on the fact that the current
-    // update_verifier has a similar I/O size.
-    size_t read_sz = 1024 * BLOCK_SZ;
-    std::vector<uint8_t> buf(read_sz);
-
-    while (remain > 0) {
-        size_t to_read = std::min(remain, read_sz);
-
-        if (!android::base::ReadFullyAtOffset(fd.get(), buf.data(), to_read, file_offset)) {
-            SNAP_PLOG(ERROR) << "Failed to read block from block device: " << dm_block_device
-                             << " at offset: " << file_offset
-                             << " partition-name: " << partition_name << " total-size: " << size
-                             << " remain_size: " << remain;
-            return;
-        }
-
-        file_offset += to_read;
-        remain -= to_read;
-    }
-
-    SNAP_LOG(INFO) << "Finished reading block-device: " << dm_block_device
-                   << " partition: " << partition_name << " size: " << size
-                   << " offset: " << offset;
-}
-
-void SnapshotHandler::ReadBlocks(const std::string partition_name,
-                                 const std::string& dm_block_device) {
-    SNAP_LOG(DEBUG) << "Reading partition: " << partition_name
-                    << " Block-Device: " << dm_block_device;
-
-    uint64_t dev_sz = 0;
-
-    unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY | O_CLOEXEC)));
-    if (fd < 0) {
-        SNAP_LOG(ERROR) << "Cannot open block device";
-        return;
-    }
-
-    dev_sz = get_block_device_size(fd.get());
-    if (!dev_sz) {
-        SNAP_PLOG(ERROR) << "Could not determine block device size: " << dm_block_device;
-        return;
-    }
-
-    int num_threads = 2;
-    size_t num_blocks = dev_sz >> BLOCK_SHIFT;
-    size_t num_blocks_per_thread = num_blocks / num_threads;
-    size_t read_sz_per_thread = num_blocks_per_thread << BLOCK_SHIFT;
-    off_t offset = 0;
-
-    for (int i = 0; i < num_threads; i++) {
-        std::async(std::launch::async, &SnapshotHandler::ReadBlocksToCache, this, dm_block_device,
-                   partition_name, offset, read_sz_per_thread);
-
-        offset += read_sz_per_thread;
-    }
-}
-
 /*
  * Entry point to launch threads
  */
@@ -527,42 +331,22 @@
                 std::async(std::launch::async, &Worker::RunThread, worker_threads_[i].get()));
     }
 
-    bool second_stage_init = true;
+    bool partition_verification = true;
 
-    // We don't want to read the blocks during first stage init.
+    // We don't want to read the blocks during first stage init or
+    // during post-install phase.
     if (android::base::EndsWith(misc_name_, "-init") || is_socket_present_) {
-        second_stage_init = false;
-    }
-
-    if (second_stage_init) {
-        SNAP_LOG(INFO) << "Reading blocks to cache....";
-        auto& dm = DeviceMapper::Instance();
-        auto dm_block_devices = dm.FindDmPartitions();
-        if (dm_block_devices.empty()) {
-            SNAP_LOG(ERROR) << "No dm-enabled block device is found.";
-        } else {
-            auto parts = android::base::Split(misc_name_, "-");
-            std::string partition_name = parts[0];
-
-            const char* suffix_b = "_b";
-            const char* suffix_a = "_a";
-
-            partition_name.erase(partition_name.find_last_not_of(suffix_b) + 1);
-            partition_name.erase(partition_name.find_last_not_of(suffix_a) + 1);
-
-            if (dm_block_devices.find(partition_name) == dm_block_devices.end()) {
-                SNAP_LOG(ERROR) << "Failed to find dm block device for " << partition_name;
-            } else {
-                ReadBlocks(partition_name, dm_block_devices.at(partition_name));
-            }
-        }
-    } else {
-        SNAP_LOG(INFO) << "Not reading block device into cache";
+        partition_verification = false;
     }
 
     std::future<bool> merge_thread =
             std::async(std::launch::async, &Worker::RunMergeThread, merge_thread_.get());
 
+    // Now that the worker threads are up, scan the partitions.
+    if (partition_verification) {
+        update_verify_->VerifyUpdatePartition();
+    }
+
     bool ret = true;
     for (auto& t : threads) {
         ret = t.get() && ret;
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h
index c6805e5..42237ef 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_core.h
@@ -45,12 +45,14 @@
 #include <liburing.h>
 #include <snapuserd/snapuserd_buffer.h>
 #include <snapuserd/snapuserd_kernel.h>
+#include <storage_literals/storage_literals.h>
 
 namespace android {
 namespace snapshot {
 
 using android::base::unique_fd;
 using namespace std::chrono_literals;
+using namespace android::storage_literals;
 
 static constexpr size_t PAYLOAD_BUFFER_SZ = (1UL << 20);
 static_assert(PAYLOAD_BUFFER_SZ >= BLOCK_SZ);
@@ -170,6 +172,36 @@
     std::unique_ptr<struct io_uring> ring_;
 };
 
+class UpdateVerify {
+  public:
+    UpdateVerify(const std::string& misc_name);
+    void VerifyUpdatePartition();
+    bool CheckPartitionVerification();
+
+  private:
+    enum class UpdateVerifyState {
+        VERIFY_UNKNOWN,
+        VERIFY_FAILED,
+        VERIFY_SUCCESS,
+    };
+
+    std::string misc_name_;
+    UpdateVerifyState state_;
+    std::mutex m_lock_;
+    std::condition_variable m_cv_;
+
+    int kMinThreadsToVerify = 1;
+    int kMaxThreadsToVerify = 4;
+    uint64_t kThresholdSize = 512_MiB;
+    uint64_t kBlockSizeVerify = 1_MiB;
+
+    bool IsBlockAligned(uint64_t read_size) { return ((read_size & (BLOCK_SZ - 1)) == 0); }
+    void UpdatePartitionVerificationState(UpdateVerifyState state);
+    bool VerifyPartition(const std::string& partition_name, const std::string& dm_block_device);
+    bool VerifyBlocks(const std::string& partition_name, const std::string& dm_block_device,
+                      off_t offset, int skip_blocks, uint64_t dev_sz);
+};
+
 class Worker {
   public:
     Worker(const std::string& cow_device, const std::string& backing_device,
@@ -352,24 +384,16 @@
     MERGE_GROUP_STATE ProcessMergingBlock(uint64_t new_block, void* buffer);
 
     bool IsIouringSupported();
+    bool CheckPartitionVerification() { return update_verify_->CheckPartitionVerification(); }
 
   private:
     bool ReadMetadata();
     sector_t ChunkToSector(chunk_t chunk) { return chunk << CHUNK_SHIFT; }
     chunk_t SectorToChunk(sector_t sector) { return sector >> CHUNK_SHIFT; }
-    bool IsBlockAligned(int read_size) { return ((read_size & (BLOCK_SZ - 1)) == 0); }
+    bool IsBlockAligned(uint64_t read_size) { return ((read_size & (BLOCK_SZ - 1)) == 0); }
     struct BufferState* GetBufferState();
     void UpdateMergeCompletionPercentage();
 
-    void ReadBlocks(const std::string partition_name, const std::string& dm_block_device);
-    void ReadBlocksToCache(const std::string& dm_block_device, const std::string& partition_name,
-                           off_t offset, size_t size);
-
-    bool InitializeIouring(int io_depth);
-    void FinalizeIouring();
-    bool ReadBlocksAsync(const std::string& dm_block_device, const std::string& partition_name,
-                         size_t size);
-
     // COW device
     std::string cow_device_;
     // Source device
@@ -422,6 +446,7 @@
     bool scratch_space_ = false;
 
     std::unique_ptr<struct io_uring> ring_;
+    std::unique_ptr<UpdateVerify> update_verify_;
 };
 
 }  // namespace snapshot
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 5d93f01..1e7daed 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.cpp
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.cpp
@@ -55,6 +55,7 @@
     if (input == "initiate_merge") return DaemonOps::INITIATE;
     if (input == "merge_percent") return DaemonOps::PERCENTAGE;
     if (input == "getstatus") return DaemonOps::GETSTATUS;
+    if (input == "update-verify") return DaemonOps::UPDATE_VERIFY;
 
     return DaemonOps::INVALID;
 }
@@ -290,6 +291,14 @@
                 return Sendmsg(fd, merge_status);
             }
         }
+        case DaemonOps::UPDATE_VERIFY: {
+            std::lock_guard<std::mutex> lock(lock_);
+            if (!UpdateVerification(&lock)) {
+                return Sendmsg(fd, "fail");
+            }
+
+            return Sendmsg(fd, "success");
+        }
         default: {
             LOG(ERROR) << "Received unknown message type from client";
             Sendmsg(fd, "fail");
@@ -750,5 +759,22 @@
     return true;
 }
 
+bool UserSnapshotServer::UpdateVerification(std::lock_guard<std::mutex>* proof_of_lock) {
+    CHECK(proof_of_lock);
+
+    bool status = true;
+    for (auto iter = dm_users_.begin(); iter != dm_users_.end(); iter++) {
+        auto& th = (*iter)->thread();
+        if (th.joinable() && status) {
+            status = (*iter)->snapuserd()->CheckPartitionVerification() && status;
+        } else {
+            // return immediately if there is a failure
+            return false;
+        }
+    }
+
+    return status;
+}
+
 }  // namespace snapshot
 }  // namespace android
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 e0844ae..c2af61f 100644
--- a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.h
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_server.h
@@ -50,6 +50,7 @@
     INITIATE,
     PERCENTAGE,
     GETSTATUS,
+    UPDATE_VERIFY,
     INVALID,
 };
 
@@ -130,6 +131,8 @@
     double GetMergePercentage(std::lock_guard<std::mutex>* proof_of_lock);
     void TerminateMergeThreads(std::lock_guard<std::mutex>* proof_of_lock);
 
+    bool UpdateVerification(std::lock_guard<std::mutex>* proof_of_lock);
+
   public:
     UserSnapshotServer();
     ~UserSnapshotServer();
diff --git a/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_verify.cpp b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_verify.cpp
new file mode 100644
index 0000000..18c1dfc
--- /dev/null
+++ b/fs_mgr/libsnapshot/snapuserd/user-space-merge/snapuserd_verify.cpp
@@ -0,0 +1,222 @@
+/*
+ * Copyright (C) 2022 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 "snapuserd_core.h"
+
+#include <android-base/chrono_utils.h>
+#include <android-base/scopeguard.h>
+#include <android-base/strings.h>
+
+namespace android {
+namespace snapshot {
+
+using namespace android;
+using namespace android::dm;
+using android::base::unique_fd;
+
+UpdateVerify::UpdateVerify(const std::string& misc_name)
+    : misc_name_(misc_name), state_(UpdateVerifyState::VERIFY_UNKNOWN) {}
+
+bool UpdateVerify::CheckPartitionVerification() {
+    auto now = std::chrono::system_clock::now();
+    auto deadline = now + 10s;
+    {
+        std::unique_lock<std::mutex> cv_lock(m_lock_);
+        while (state_ == UpdateVerifyState::VERIFY_UNKNOWN) {
+            auto status = m_cv_.wait_until(cv_lock, deadline);
+            if (status == std::cv_status::timeout) {
+                return false;
+            }
+        }
+    }
+
+    return (state_ == UpdateVerifyState::VERIFY_SUCCESS);
+}
+
+void UpdateVerify::UpdatePartitionVerificationState(UpdateVerifyState state) {
+    {
+        std::lock_guard<std::mutex> lock(m_lock_);
+        state_ = state;
+    }
+    m_cv_.notify_all();
+}
+
+void UpdateVerify::VerifyUpdatePartition() {
+    bool succeeded = false;
+
+    auto scope_guard = android::base::make_scope_guard([this, &succeeded]() -> void {
+        if (!succeeded) {
+            UpdatePartitionVerificationState(UpdateVerifyState::VERIFY_FAILED);
+        }
+    });
+
+    auto& dm = DeviceMapper::Instance();
+    auto dm_block_devices = dm.FindDmPartitions();
+    if (dm_block_devices.empty()) {
+        SNAP_LOG(ERROR) << "No dm-enabled block device is found.";
+        return;
+    }
+
+    const auto parts = android::base::Split(misc_name_, "-");
+    std::string partition_name = parts[0];
+
+    constexpr auto&& suffix_b = "_b";
+    constexpr auto&& suffix_a = "_a";
+
+    partition_name.erase(partition_name.find_last_not_of(suffix_b) + 1);
+    partition_name.erase(partition_name.find_last_not_of(suffix_a) + 1);
+
+    if (dm_block_devices.find(partition_name) == dm_block_devices.end()) {
+        SNAP_LOG(ERROR) << "Failed to find dm block device for " << partition_name;
+        return;
+    }
+
+    if (!VerifyPartition(partition_name, dm_block_devices.at(partition_name))) {
+        SNAP_LOG(ERROR) << "Partition: " << partition_name
+                        << " Block-device: " << dm_block_devices.at(partition_name)
+                        << " verification failed";
+    }
+    succeeded = true;
+}
+
+bool UpdateVerify::VerifyBlocks(const std::string& partition_name,
+                                const std::string& dm_block_device, off_t offset, int skip_blocks,
+                                uint64_t dev_sz) {
+    unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY | O_DIRECT)));
+    if (fd < 0) {
+        SNAP_LOG(ERROR) << "open failed: " << dm_block_device;
+        return false;
+    }
+
+    loff_t file_offset = offset;
+    const uint64_t read_sz = kBlockSizeVerify;
+
+    void* addr;
+    ssize_t page_size = getpagesize();
+    if (posix_memalign(&addr, page_size, read_sz) < 0) {
+        SNAP_PLOG(ERROR) << "posix_memalign failed "
+                         << " page_size: " << page_size << " read_sz: " << read_sz;
+        return false;
+    }
+
+    std::unique_ptr<void, decltype(&::free)> buffer(addr, ::free);
+
+    uint64_t bytes_read = 0;
+
+    while (true) {
+        size_t to_read = std::min((dev_sz - file_offset), read_sz);
+
+        if (!android::base::ReadFullyAtOffset(fd.get(), buffer.get(), to_read, file_offset)) {
+            SNAP_PLOG(ERROR) << "Failed to read block from block device: " << dm_block_device
+                             << " partition-name: " << partition_name
+                             << " at offset: " << file_offset << " read-size: " << to_read
+                             << " block-size: " << dev_sz;
+            return false;
+        }
+
+        bytes_read += to_read;
+        file_offset += (skip_blocks * kBlockSizeVerify);
+        if (file_offset >= dev_sz) {
+            break;
+        }
+    }
+
+    SNAP_LOG(DEBUG) << "Verification success with bytes-read: " << bytes_read
+                    << " dev_sz: " << dev_sz << " partition_name: " << partition_name;
+
+    return true;
+}
+
+bool UpdateVerify::VerifyPartition(const std::string& partition_name,
+                                   const std::string& dm_block_device) {
+    android::base::Timer timer;
+
+    SNAP_LOG(INFO) << "VerifyPartition: " << partition_name << " Block-device: " << dm_block_device;
+
+    bool succeeded = false;
+    auto scope_guard = android::base::make_scope_guard([this, &succeeded]() -> void {
+        if (!succeeded) {
+            UpdatePartitionVerificationState(UpdateVerifyState::VERIFY_FAILED);
+        }
+    });
+
+    unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY | O_DIRECT)));
+    if (fd < 0) {
+        SNAP_LOG(ERROR) << "open failed: " << dm_block_device;
+        return false;
+    }
+
+    uint64_t dev_sz = get_block_device_size(fd.get());
+    if (!dev_sz) {
+        SNAP_PLOG(ERROR) << "Could not determine block device size: " << dm_block_device;
+        return false;
+    }
+
+    if (!IsBlockAligned(dev_sz)) {
+        SNAP_LOG(ERROR) << "dev_sz: " << dev_sz << " is not block aligned";
+        return false;
+    }
+
+    /*
+     * Not all partitions are of same size. Some partitions are as small as
+     * 100Mb. We can just finish them in a single thread. For bigger partitions
+     * such as product, 4 threads are sufficient enough.
+     *
+     * TODO: With io_uring SQ_POLL support, we can completely cut this
+     * down to just single thread for all partitions and potentially verify all
+     * the partitions with zero syscalls. Additionally, since block layer
+     * supports polling, IO_POLL could be used which will further cut down
+     * latency.
+     */
+    int num_threads = kMinThreadsToVerify;
+    if (dev_sz > kThresholdSize) {
+        num_threads = kMaxThreadsToVerify;
+    }
+
+    std::vector<std::future<bool>> threads;
+    off_t start_offset = 0;
+    const int skip_blocks = num_threads;
+
+    while (num_threads) {
+        threads.emplace_back(std::async(std::launch::async, &UpdateVerify::VerifyBlocks, this,
+                                        partition_name, dm_block_device, start_offset, skip_blocks,
+                                        dev_sz));
+        start_offset += kBlockSizeVerify;
+        num_threads -= 1;
+        if (start_offset >= dev_sz) {
+            break;
+        }
+    }
+
+    bool ret = true;
+    for (auto& t : threads) {
+        ret = t.get() && ret;
+    }
+
+    if (ret) {
+        succeeded = true;
+        UpdatePartitionVerificationState(UpdateVerifyState::VERIFY_SUCCESS);
+        SNAP_LOG(INFO) << "Partition: " << partition_name << " Block-device: " << dm_block_device
+                       << " Size: " << dev_sz
+                       << " verification success. Duration : " << timer.duration().count() << " ms";
+        return true;
+    }
+
+    return false;
+}
+
+}  // namespace snapshot
+}  // namespace android