diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index f154138..aa9bf88 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -35,9 +35,11 @@
         "update_metadata-protos",
     ],
     whole_static_libs: [
+        "libcutils",
         "libext2_uuid",
         "libext4_utils",
         "libfstab",
+        "libsnapshot_snapuserd",
     ],
     header_libs: [
         "libchrome",
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index 0764bc7..35ed04a 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -37,6 +37,7 @@
 #include <libsnapshot/auto_device.h>
 #include <libsnapshot/return.h>
 #include <libsnapshot/snapshot_writer.h>
+#include <libsnapshot/snapuserd_client.h>
 
 #ifndef FRIEND_TEST
 #define FRIEND_TEST(test_set_name, individual_test) \
@@ -368,6 +369,9 @@
     // This is created lazily since it can connect via binder.
     bool EnsureImageManager();
 
+    // Ensure we're connected to snapuserd.
+    bool EnsureSnapuserdConnected();
+
     // Helper for first-stage init.
     bool ForceLocalImageManager();
 
@@ -424,6 +428,11 @@
                      const std::string& cow_device, const std::chrono::milliseconds& timeout_ms,
                      std::string* dev_path);
 
+    // Create a dm-user device for a given snapshot.
+    bool MapDmUserCow(LockedFile* lock, const std::string& name, const std::string& cow_file,
+                      const std::string& base_device, const std::chrono::milliseconds& timeout_ms,
+                      std::string* path);
+
     // Map a COW image that was previous created with CreateCowImage.
     std::optional<std::string> MapCowImage(const std::string& name,
                                            const std::chrono::milliseconds& timeout_ms);
@@ -652,6 +661,7 @@
     std::unique_ptr<IImageManager> images_;
     bool has_local_image_manager_ = false;
     bool in_factory_data_reset_ = false;
+    std::unique_ptr<SnapuserdClient> snapuserd_client_;
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapuserd.h b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd.h
index 2f727d6..80f87d9 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapuserd.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd.h
@@ -77,7 +77,7 @@
     int ReadDiskExceptions(chunk_t chunk, size_t size);
     int ReadData(chunk_t chunk, size_t size);
 
-    std::string GetControlDevicePath() { return control_device_; }
+    const std::string& GetControlDevicePath() { return control_device_; }
 
   private:
     int ProcessReplaceOp(const CowOperation* cow_op);
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h
index dffd481..0bbdaa5 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_client.h
@@ -53,6 +53,10 @@
     int RestartSnapuserd(std::vector<std::vector<std::string>>& vec);
     bool InitializeSnapuserd(const std::string& cow_device, const std::string& backing_device,
                              const std::string& control_device);
+
+    // Wait for snapuserd to disassociate with a dm-user control device. This
+    // must ONLY be called if the control device has already been deleted.
+    bool WaitForDeviceDelete(const std::string& control_device);
 };
 
 }  // namespace snapshot
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_server.h b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_server.h
index 357acac..181ee33 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_server.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapuserd_server.h
@@ -21,12 +21,14 @@
 #include <functional>
 #include <future>
 #include <iostream>
+#include <mutex>
 #include <sstream>
 #include <string>
 #include <thread>
 #include <vector>
 
 #include <android-base/unique_fd.h>
+#include <libsnapshot/snapuserd.h>
 
 namespace android {
 namespace snapshot {
@@ -37,19 +39,23 @@
     START,
     QUERY,
     STOP,
+    DELETE,
     INVALID,
 };
 
 class DmUserHandler {
   private:
-    std::unique_ptr<std::thread> threadHandler_;
+    std::thread thread_;
+    std::unique_ptr<Snapuserd> snapuserd_;
 
   public:
-    void SetThreadHandler(std::function<void(void)> func) {
-        threadHandler_ = std::make_unique<std::thread>(func);
-    }
+    explicit DmUserHandler(std::unique_ptr<Snapuserd>&& snapuserd)
+        : snapuserd_(std::move(snapuserd)) {}
 
-    std::unique_ptr<std::thread>& GetThreadHandler() { return threadHandler_; }
+    const std::unique_ptr<Snapuserd>& snapuserd() const { return snapuserd_; }
+    std::thread& thread() { return thread_; }
+
+    const std::string& GetControlDevice() const;
 };
 
 class Stoppable {
@@ -61,9 +67,6 @@
 
     virtual ~Stoppable() {}
 
-    virtual void ThreadStart(std::string cow_device, std::string backing_device,
-                             std::string control_device) = 0;
-
     bool StopRequested() {
         // checks if value in future object is available
         if (futureObj_.wait_for(std::chrono::milliseconds(0)) == std::future_status::timeout)
@@ -78,27 +81,33 @@
   private:
     android::base::unique_fd sockfd_;
     bool terminating_;
-    std::vector<std::unique_ptr<DmUserHandler>> dm_users_;
     std::vector<struct pollfd> watched_fds_;
 
+    std::mutex lock_;
+    std::vector<std::unique_ptr<DmUserHandler>> dm_users_;
+
     void AddWatchedFd(android::base::borrowed_fd fd);
     void AcceptClient();
     bool HandleClient(android::base::borrowed_fd fd, int revents);
     bool Recv(android::base::borrowed_fd fd, std::string* data);
     bool Sendmsg(android::base::borrowed_fd fd, const std::string& msg);
-    bool Receivemsg(android::base::borrowed_fd fd, const std::string& msg);
+    bool Receivemsg(android::base::borrowed_fd fd, const std::string& str);
 
-    void ThreadStart(std::string cow_device, std::string backing_device,
-                     std::string control_device) override;
     void ShutdownThreads();
+    bool WaitForDelete(const std::string& control_device);
     DaemonOperations Resolveop(std::string& input);
     std::string GetDaemonStatus();
     void Parsemsg(std::string const& msg, const char delim, std::vector<std::string>& out);
 
     void SetTerminating() { terminating_ = true; }
-
     bool IsTerminating() { return terminating_; }
 
+    void RunThread(DmUserHandler* handler);
+
+    // Remove a DmUserHandler from dm_users_, searching by its control device.
+    // If none is found, return nullptr.
+    std::unique_ptr<DmUserHandler> RemoveHandler(const std::string& control_device);
+
   public:
     SnapuserdServer() { terminating_ = false; }
     ~SnapuserdServer();
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index e42e668..7061d56 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -56,6 +56,7 @@
 using android::dm::DmTable;
 using android::dm::DmTargetLinear;
 using android::dm::DmTargetSnapshot;
+using android::dm::DmTargetUser;
 using android::dm::kSectorSize;
 using android::dm::SnapshotStorageMode;
 using android::fiemap::FiemapStatus;
@@ -115,6 +116,10 @@
     return snapshot_name + "-cow";
 }
 
+static std::string GetDmUserCowName(const std::string& snapshot_name) {
+    return snapshot_name + "-user-cow";
+}
+
 static std::string GetCowImageDeviceName(const std::string& snapshot_name) {
     return snapshot_name + "-cow-img";
 }
@@ -370,6 +375,45 @@
     return Return(images_->CreateBackingImage(cow_image_name, status.cow_file_size(), cow_flags));
 }
 
+bool SnapshotManager::MapDmUserCow(LockedFile* lock, const std::string& name,
+                                   const std::string& cow_file, const std::string& base_device,
+                                   const std::chrono::milliseconds& timeout_ms, std::string* path) {
+    CHECK(lock);
+
+    auto& dm = DeviceMapper::Instance();
+
+    // Use the size of the base device for the COW device. It doesn't really
+    // matter, it just needs to look similar enough so the kernel doesn't complain
+    // about alignment or being too small.
+    uint64_t base_sectors = 0;
+    {
+        unique_fd fd(open(base_device.c_str(), O_RDONLY | O_CLOEXEC));
+        if (fd < 0) {
+            PLOG(ERROR) << "open failed: " << base_device;
+            return false;
+        }
+        auto dev_size = get_block_device_size(fd);
+        if (!dev_size) {
+            PLOG(ERROR) << "Could not determine block device size: " << base_device;
+            return false;
+        }
+        base_sectors = dev_size / kSectorSize;
+    }
+
+    DmTable table;
+    table.Emplace<DmTargetUser>(0, base_sectors, name);
+    if (!dm.CreateDevice(name, table, path, timeout_ms)) {
+        return false;
+    }
+
+    if (!EnsureSnapuserdConnected()) {
+        return false;
+    }
+
+    auto control_device = "/dev/dm-user/" + name;
+    return snapuserd_client_->InitializeSnapuserd(cow_file, base_device, control_device);
+}
+
 bool SnapshotManager::MapSnapshot(LockedFile* lock, const std::string& name,
                                   const std::string& base_device, const std::string& cow_device,
                                   const std::chrono::milliseconds& timeout_ms,
@@ -1728,6 +1772,30 @@
         return true;
     }
 
+    if (IsCompressionEnabled()) {
+        auto name = GetDmUserCowName(params.GetPartitionName());
+
+        // :TODO: need to force init to process uevents for these in first-stage.
+        std::string cow_path;
+        if (!GetMappedImageDevicePath(cow_name, &cow_path)) {
+            LOG(ERROR) << "Could not determine path for: " << cow_name;
+            return false;
+        }
+
+        std::string new_cow_device;
+        if (!MapDmUserCow(lock, name, cow_path, base_path, remaining_time, &new_cow_device)) {
+            LOG(ERROR) << "Could not map dm-user device for partition "
+                       << params.GetPartitionName();
+            return false;
+        }
+        created_devices.EmplaceBack<AutoUnmapDevice>(&dm, name);
+
+        remaining_time = GetRemainingTime(params.timeout_ms, begin);
+        if (remaining_time.count() < 0) return false;
+
+        cow_device = new_cow_device;
+    }
+
     std::string path;
     if (!MapSnapshot(lock, params.GetPartitionName(), base_device, cow_device, remaining_time,
                      &path)) {
@@ -1847,6 +1915,22 @@
     if (!EnsureImageManager()) return false;
 
     auto& dm = DeviceMapper::Instance();
+
+    auto dm_user_name = GetDmUserCowName(name);
+    if (IsCompressionEnabled() && dm.GetState(dm_user_name) != DmDeviceState::INVALID) {
+        if (!EnsureSnapuserdConnected()) {
+            return false;
+        }
+        if (!dm.DeleteDevice(dm_user_name)) {
+            LOG(ERROR) << "Cannot unmap " << dm_user_name;
+            return false;
+        }
+        if (!snapuserd_client_->WaitForDeviceDelete("/dev/dm-user/" + dm_user_name)) {
+            LOG(ERROR) << "Failed to wait for " << dm_user_name << " control device to delete";
+            return false;
+        }
+    }
+
     auto cow_name = GetCowName(name);
     if (!dm.DeleteDeviceIfExists(cow_name)) {
         LOG(ERROR) << "Cannot unmap " << cow_name;
@@ -2127,6 +2211,20 @@
     return true;
 }
 
+bool SnapshotManager::EnsureSnapuserdConnected() {
+    if (!snapuserd_client_) {
+        if (!EnsureSnapuserdStarted()) {
+            return false;
+        }
+        snapuserd_client_ = SnapuserdClient::Connect(kSnapuserdSocket, 10s);
+        if (!snapuserd_client_) {
+            LOG(ERROR) << "Unable to connect to snapuserd";
+            return false;
+        }
+    }
+    return true;
+}
+
 bool SnapshotManager::ForceLocalImageManager() {
     images_ = android::fiemap::ImageManager::Open(gsid_dir_);
     if (!images_) {
diff --git a/fs_mgr/libsnapshot/snapuserd_client.cpp b/fs_mgr/libsnapshot/snapuserd_client.cpp
index 532e585..35bb29b 100644
--- a/fs_mgr/libsnapshot/snapuserd_client.cpp
+++ b/fs_mgr/libsnapshot/snapuserd_client.cpp
@@ -123,34 +123,32 @@
     return true;
 }
 
-std::string SnapuserdClient::Receivemsg() {
-    int ret;
-    struct timeval tv;
-    fd_set set;
-    char msg[PACKET_SIZE];
-    std::string msgStr("fail");
-
-    tv.tv_sec = 2;
-    tv.tv_usec = 0;
-    FD_ZERO(&set);
-    FD_SET(sockfd_, &set);
-    ret = select(sockfd_ + 1, &set, NULL, NULL, &tv);
-    if (ret == -1) {  // select failed
-        LOG(ERROR) << "Snapuserd:client: Select call failed";
-    } else if (ret == 0) {  // timeout
-        LOG(ERROR) << "Snapuserd:client: Select call timeout";
-    } else {
-        ret = TEMP_FAILURE_RETRY(recv(sockfd_, msg, PACKET_SIZE, 0));
-        if (ret < 0) {
-            PLOG(ERROR) << "Snapuserd:client: recv failed";
-        } else if (ret == 0) {
-            LOG(DEBUG) << "Snapuserd:client disconnected";
-        } else {
-            msgStr.clear();
-            msgStr = msg;
-        }
+bool SnapuserdClient::WaitForDeviceDelete(const std::string& control_device) {
+    std::string msg = "delete," + control_device;
+    if (!Sendmsg(msg)) {
+        LOG(ERROR) << "Failed to send message " << msg << " to snapuserd";
+        return false;
     }
-    return msgStr;
+    std::string response = Receivemsg();
+    if (response != "success") {
+        LOG(ERROR) << "Failed waiting to delete device " << control_device;
+        return false;
+    }
+    return true;
+}
+
+std::string SnapuserdClient::Receivemsg() {
+    char msg[PACKET_SIZE];
+    ssize_t ret = TEMP_FAILURE_RETRY(recv(sockfd_, msg, sizeof(msg), 0));
+    if (ret < 0) {
+        PLOG(ERROR) << "Snapuserd:client: recv failed";
+        return {};
+    }
+    if (ret == 0) {
+        LOG(DEBUG) << "Snapuserd:client disconnected";
+        return {};
+    }
+    return std::string(msg, ret);
 }
 
 bool SnapuserdClient::StopSnapuserd() {
diff --git a/fs_mgr/libsnapshot/snapuserd_server.cpp b/fs_mgr/libsnapshot/snapuserd_server.cpp
index 48a3b2a..6b8cdd9 100644
--- a/fs_mgr/libsnapshot/snapuserd_server.cpp
+++ b/fs_mgr/libsnapshot/snapuserd_server.cpp
@@ -36,6 +36,7 @@
     if (input == "start") return DaemonOperations::START;
     if (input == "stop") return DaemonOperations::STOP;
     if (input == "query") return DaemonOperations::QUERY;
+    if (input == "delete") return DaemonOperations::DELETE;
 
     return DaemonOperations::INVALID;
 }
@@ -68,33 +69,25 @@
     }
 }
 
-// new thread
-void SnapuserdServer::ThreadStart(std::string cow_device, std::string backing_device,
-                                  std::string control_device) {
-    Snapuserd snapd(cow_device, backing_device, control_device);
-    if (!snapd.Init()) {
-        LOG(ERROR) << "Snapuserd: Init failed";
-        return;
-    }
-
-    while (StopRequested() == false) {
-        int ret = snapd.Run();
-
-        if (ret < 0) {
-            LOG(ERROR) << "Snapuserd: Thread terminating as control device is de-registered";
-            break;
-        }
-    }
-}
-
 void SnapuserdServer::ShutdownThreads() {
     StopThreads();
 
-    for (auto& client : dm_users_) {
-        auto& th = client->GetThreadHandler();
-
-        if (th->joinable()) th->join();
+    // Acquire the thread list within the lock.
+    std::vector<std::unique_ptr<DmUserHandler>> dm_users;
+    {
+        std::lock_guard<std::mutex> guard(lock_);
+        dm_users = std::move(dm_users_);
     }
+
+    for (auto& client : dm_users) {
+        auto& th = client->thread();
+
+        if (th.joinable()) th.join();
+    }
+}
+
+const std::string& DmUserHandler::GetControlDevice() const {
+    return snapuserd_->GetControlDevicePath();
 }
 
 bool SnapuserdServer::Sendmsg(android::base::borrowed_fd fd, const std::string& msg) {
@@ -135,10 +128,25 @@
             // start,<cow_device_path>,<source_device_path>,<control_device>
             //
             // Start the new thread which binds to dm-user misc device
-            auto handler = std::make_unique<DmUserHandler>();
-            handler->SetThreadHandler(
-                    std::bind(&SnapuserdServer::ThreadStart, this, out[1], out[2], out[3]));
-            dm_users_.push_back(std::move(handler));
+            if (out.size() != 4) {
+                LOG(ERROR) << "Malformed start message, " << out.size() << " parts";
+                return Sendmsg(fd, "fail");
+            }
+
+            auto snapuserd = std::make_unique<Snapuserd>(out[1], out[2], out[3]);
+            if (!snapuserd->Init()) {
+                LOG(ERROR) << "Failed to initialize Snapuserd";
+                return Sendmsg(fd, "fail");
+            }
+
+            auto handler = std::make_unique<DmUserHandler>(std::move(snapuserd));
+            {
+                std::lock_guard<std::mutex> lock(lock_);
+
+                handler->thread() =
+                        std::thread(std::bind(&SnapuserdServer::RunThread, this, handler.get()));
+                dm_users_.push_back(std::move(handler));
+            }
             return Sendmsg(fd, "success");
         }
         case DaemonOperations::STOP: {
@@ -162,6 +170,18 @@
             // be ready to receive control message.
             return Sendmsg(fd, GetDaemonStatus());
         }
+        case DaemonOperations::DELETE: {
+            // Message format:
+            // delete,<cow_device_path>
+            if (out.size() != 2) {
+                LOG(ERROR) << "Malformed delete message, " << out.size() << " parts";
+                return Sendmsg(fd, "fail");
+            }
+            if (!WaitForDelete(out[1])) {
+                return Sendmsg(fd, "fail");
+            }
+            return Sendmsg(fd, "success");
+        }
         default: {
             LOG(ERROR) << "Received unknown message type from client";
             Sendmsg(fd, "fail");
@@ -170,6 +190,23 @@
     }
 }
 
+void SnapuserdServer::RunThread(DmUserHandler* handler) {
+    while (!StopRequested()) {
+        if (handler->snapuserd()->Run() < 0) {
+            LOG(INFO) << "Snapuserd: Thread terminating as control device is de-registered";
+            break;
+        }
+    }
+
+    if (auto client = RemoveHandler(handler->GetControlDevice())) {
+        // The main thread did not receive a WaitForDelete request for this
+        // control device. Since we transferred ownership within the lock,
+        // we know join() was never called, and will never be called. We can
+        // safely detach here.
+        client->thread().detach();
+    }
+}
+
 bool SnapuserdServer::Start(const std::string& socketname) {
     sockfd_.reset(android_get_control_socket(socketname.c_str()));
     if (sockfd_ >= 0) {
@@ -260,5 +297,37 @@
     SetTerminating();
 }
 
+std::unique_ptr<DmUserHandler> SnapuserdServer::RemoveHandler(const std::string& control_device) {
+    std::unique_ptr<DmUserHandler> client;
+    {
+        std::lock_guard<std::mutex> lock(lock_);
+        auto iter = dm_users_.begin();
+        while (iter != dm_users_.end()) {
+            if ((*iter)->GetControlDevice() == control_device) {
+                client = std::move(*iter);
+                iter = dm_users_.erase(iter);
+                break;
+            }
+            iter++;
+        }
+    }
+    return client;
+}
+
+bool SnapuserdServer::WaitForDelete(const std::string& control_device) {
+    auto client = RemoveHandler(control_device);
+
+    // Client already deleted.
+    if (!client) {
+        return true;
+    }
+
+    auto& th = client->thread();
+    if (th.joinable()) {
+        th.join();
+    }
+    return true;
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/init/Android.mk b/init/Android.mk
index 895f50f..ac31ef1 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -78,7 +78,6 @@
 LOCAL_POST_INSTALL_CMD := mkdir -p \
     $(TARGET_RAMDISK_OUT)/debug_ramdisk \
     $(TARGET_RAMDISK_OUT)/dev \
-    $(TARGET_RAMDISK_OUT)/first_stage_ramdisk \
     $(TARGET_RAMDISK_OUT)/mnt \
     $(TARGET_RAMDISK_OUT)/proc \
     $(TARGET_RAMDISK_OUT)/second_stage_resources \