diff --git a/fs_mgr/libdm/include/libdm/dm.h b/fs_mgr/libdm/include/libdm/dm.h
index 7e01b85..332fcf5 100644
--- a/fs_mgr/libdm/include/libdm/dm.h
+++ b/fs_mgr/libdm/include/libdm/dm.h
@@ -55,7 +55,33 @@
 // that prefix.
 std::optional<std::string> ExtractBlockDeviceName(const std::string& path);
 
-class DeviceMapper final {
+// This interface is for testing purposes. See DeviceMapper proper for what these methods do.
+class IDeviceMapper {
+  public:
+    virtual ~IDeviceMapper() {}
+
+    struct TargetInfo {
+        struct dm_target_spec spec;
+        std::string data;
+        TargetInfo() {}
+        TargetInfo(const struct dm_target_spec& spec, const std::string& data)
+            : spec(spec), data(data) {}
+
+        bool IsOverflowSnapshot() const;
+    };
+
+    virtual bool CreateDevice(const std::string& name, const DmTable& table, std::string* path,
+                              const std::chrono::milliseconds& timeout_ms) = 0;
+    virtual DmDeviceState GetState(const std::string& name) const = 0;
+    virtual bool LoadTableAndActivate(const std::string& name, const DmTable& table) = 0;
+    virtual bool GetTableInfo(const std::string& name, std::vector<TargetInfo>* table) = 0;
+    virtual bool GetTableStatus(const std::string& name, std::vector<TargetInfo>* table) = 0;
+    virtual bool GetDmDevicePathByName(const std::string& name, std::string* path) = 0;
+    virtual bool GetDeviceString(const std::string& name, std::string* dev) = 0;
+    virtual bool DeleteDeviceIfExists(const std::string& name) = 0;
+};
+
+class DeviceMapper final : public IDeviceMapper {
   public:
     class DmBlockDevice final {
       public:
@@ -95,7 +121,7 @@
     // Removes a device mapper device with the given name.
     // Returns 'true' on success, false otherwise.
     bool DeleteDevice(const std::string& name);
-    bool DeleteDeviceIfExists(const std::string& name);
+    bool DeleteDeviceIfExists(const std::string& name) override;
     // Removes a device mapper device with the given name and waits for |timeout_ms| milliseconds
     // for the corresponding block device to be deleted.
     bool DeleteDevice(const std::string& name, const std::chrono::milliseconds& timeout_ms);
@@ -114,7 +140,7 @@
     // Returns the current state of the underlying device mapper device
     // with given name.
     // One of INVALID, SUSPENDED or ACTIVE.
-    DmDeviceState GetState(const std::string& name) const;
+    DmDeviceState GetState(const std::string& name) const override;
 
     // Puts the given device to the specified status, which must be either:
     // - SUSPENDED: suspend the device, or
@@ -158,7 +184,7 @@
     // not |path| is available. It is the caller's responsibility to ensure
     // there are no races.
     bool CreateDevice(const std::string& name, const DmTable& table, std::string* path,
-                      const std::chrono::milliseconds& timeout_ms);
+                      const std::chrono::milliseconds& timeout_ms) override;
 
     // Create a device and activate the given table, without waiting to acquire
     // a valid path. If the caller will use GetDmDevicePathByName(), it should
@@ -170,7 +196,7 @@
     // process. A device with the given name must already exist.
     //
     // Returns 'true' on success, false otherwise.
-    bool LoadTableAndActivate(const std::string& name, const DmTable& table);
+    bool LoadTableAndActivate(const std::string& name, const DmTable& table) override;
 
     // Returns true if a list of available device mapper targets registered in the kernel was
     // successfully read and stored in 'targets'. Returns 'false' otherwise.
@@ -216,7 +242,7 @@
 
     // Returns a major:minor string for the named device-mapper node, that can
     // be used as inputs to DmTargets that take a block device.
-    bool GetDeviceString(const std::string& name, std::string* dev);
+    bool GetDeviceString(const std::string& name, std::string* dev) override;
 
     // The only way to create a DeviceMapper object.
     static DeviceMapper& Instance();
@@ -231,20 +257,11 @@
     // contain one TargetInfo for each target in the table. If the device does
     // not exist, or there were too many targets, the call will fail and return
     // false.
-    struct TargetInfo {
-        struct dm_target_spec spec;
-        std::string data;
-        TargetInfo() {}
-        TargetInfo(const struct dm_target_spec& spec, const std::string& data)
-            : spec(spec), data(data) {}
-
-        bool IsOverflowSnapshot() const;
-    };
-    bool GetTableStatus(const std::string& name, std::vector<TargetInfo>* table);
+    bool GetTableStatus(const std::string& name, std::vector<TargetInfo>* table) override;
 
     // Identical to GetTableStatus, except also retrives the active table for the device
     // mapper device from the kernel.
-    bool GetTableInfo(const std::string& name, std::vector<TargetInfo>* table);
+    bool GetTableInfo(const std::string& name, std::vector<TargetInfo>* table) override;
 
     static std::string GetTargetType(const struct dm_target_spec& spec);
 
diff --git a/fs_mgr/libfs_avb/Android.bp b/fs_mgr/libfs_avb/Android.bp
index 0cbd9db..a0ad208 100644
--- a/fs_mgr/libfs_avb/Android.bp
+++ b/fs_mgr/libfs_avb/Android.bp
@@ -152,6 +152,7 @@
     static_libs: [
         "libavb",
         "libdm",
+        "libext2_uuid",
         "libfs_avb",
         "libfstab",
     ],
diff --git a/fs_mgr/libsnapshot/device_info.cpp b/fs_mgr/libsnapshot/device_info.cpp
index 14ce0ee..a6d96ed 100644
--- a/fs_mgr/libsnapshot/device_info.cpp
+++ b/fs_mgr/libsnapshot/device_info.cpp
@@ -139,5 +139,9 @@
     }
 }
 
+android::dm::IDeviceMapper& DeviceInfo::GetDeviceMapper() {
+    return android::dm::DeviceMapper::Instance();
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/device_info.h b/fs_mgr/libsnapshot/device_info.h
index 7999c99..8aefb85 100644
--- a/fs_mgr/libsnapshot/device_info.h
+++ b/fs_mgr/libsnapshot/device_info.h
@@ -40,6 +40,7 @@
     bool IsRecovery() const override;
     std::unique_ptr<IImageManager> OpenImageManager() const override;
     bool IsFirstStageInit() const override;
+    android::dm::IDeviceMapper& GetDeviceMapper() override;
 
     void set_first_stage_init(bool value) { first_stage_init_ = value; }
 
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index d9a0cd9..55f4ed7 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -110,6 +110,7 @@
         virtual bool IsTestDevice() const { return false; }
         virtual bool IsFirstStageInit() const = 0;
         virtual std::unique_ptr<IImageManager> OpenImageManager() const = 0;
+        virtual android::dm::IDeviceMapper& GetDeviceMapper() = 0;
 
         // Helper method for implementing OpenImageManager.
         std::unique_ptr<IImageManager> OpenImageManager(const std::string& gsid_dir) const;
@@ -611,6 +612,14 @@
     MergeFailureCode CheckMergeConsistency(LockedFile* lock, const std::string& name,
                                            const SnapshotStatus& update_status);
 
+    // Get status or table information about a device-mapper node with a single target.
+    enum class TableQuery {
+        Table,
+        Status,
+    };
+    bool GetSingleTarget(const std::string& dm_name, TableQuery query,
+                         android::dm::DeviceMapper::TargetInfo* target);
+
     // Interact with status files under /metadata/ota/snapshots.
     bool WriteSnapshotStatus(LockedFile* lock, const SnapshotStatus& status);
     bool ReadSnapshotStatus(LockedFile* lock, const std::string& name, SnapshotStatus* status);
@@ -773,9 +782,9 @@
     bool DeleteDeviceIfExists(const std::string& name,
                               const std::chrono::milliseconds& timeout_ms = {});
 
-    std::string gsid_dir_;
-    std::string metadata_dir_;
+    android::dm::IDeviceMapper& dm_;
     std::unique_ptr<IDeviceInfo> device_;
+    std::string metadata_dir_;
     std::unique_ptr<IImageManager> images_;
     bool use_first_stage_snapuserd_ = false;
     bool in_factory_data_reset_ = false;
diff --git a/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h b/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
index 4e7ccf1..1f57bbc 100644
--- a/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
+++ b/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
@@ -99,6 +99,9 @@
     std::unique_ptr<IImageManager> OpenImageManager() const override {
         return IDeviceInfo::OpenImageManager("ota/test");
     }
+    android::dm::IDeviceMapper& GetDeviceMapper() override {
+        return android::dm::DeviceMapper::Instance();
+    }
 
     bool IsSlotUnbootable(uint32_t slot) { return unbootable_slots_.count(slot) != 0; }
 
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index b64dfb5..3d8ae29 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -114,9 +114,8 @@
     return sm;
 }
 
-SnapshotManager::SnapshotManager(IDeviceInfo* device) : device_(device) {
-    metadata_dir_ = device_->GetMetadataDir();
-}
+SnapshotManager::SnapshotManager(IDeviceInfo* device)
+    : dm_(device->GetDeviceMapper()), device_(device), metadata_dir_(device_->GetMetadataDir()) {}
 
 static std::string GetCowName(const std::string& snapshot_name) {
     return snapshot_name + "-cow";
@@ -402,8 +401,6 @@
                                    const std::chrono::milliseconds& timeout_ms, std::string* path) {
     CHECK(lock);
 
-    auto& dm = DeviceMapper::Instance();
-
     // Use an extra decoration for first-stage init, so we can transition
     // to a new table entry in second-stage.
     std::string misc_name = name;
@@ -423,7 +420,7 @@
 
     DmTable table;
     table.Emplace<DmTargetUser>(0, base_sectors, misc_name);
-    if (!dm.CreateDevice(name, table, path, timeout_ms)) {
+    if (!dm_.CreateDevice(name, table, path, timeout_ms)) {
         return false;
     }
     if (!WaitForDevice(*path, timeout_ms)) {
@@ -490,8 +487,6 @@
 
     uint64_t snapshot_sectors = status.snapshot_size() / kSectorSize;
 
-    auto& dm = DeviceMapper::Instance();
-
     // Note that merging is a global state. We do track whether individual devices
     // have completed merging, but the start of the merge process is considered
     // atomic.
@@ -528,7 +523,7 @@
     DmTable table;
     table.Emplace<DmTargetSnapshot>(0, snapshot_sectors, base_device, cow_device, mode,
                                     kSnapshotChunkSize);
-    if (!dm.CreateDevice(name, table, dev_path, timeout_ms)) {
+    if (!dm_.CreateDevice(name, table, dev_path, timeout_ms)) {
         LOG(ERROR) << "Could not create snapshot device: " << name;
         return false;
     }
@@ -659,7 +654,6 @@
 
     auto other_suffix = device_->GetOtherSlotSuffix();
 
-    auto& dm = DeviceMapper::Instance();
     for (const auto& snapshot : snapshots) {
         if (android::base::EndsWith(snapshot, other_suffix)) {
             // Allow the merge to continue, but log this unexpected case.
@@ -671,7 +665,7 @@
         // the same time. This is a fairly serious error. We could forcefully
         // map everything here, but it should have been mapped during first-
         // stage init.
-        if (dm.GetState(snapshot) == DmDeviceState::INVALID) {
+        if (dm_.GetState(snapshot) == DmDeviceState::INVALID) {
             LOG(ERROR) << "Cannot begin merge; device " << snapshot << " is not mapped.";
             return false;
         }
@@ -804,10 +798,8 @@
 }
 
 MergeFailureCode SnapshotManager::RewriteSnapshotDeviceTable(const std::string& name) {
-    auto& dm = DeviceMapper::Instance();
-
     std::vector<DeviceMapper::TargetInfo> old_targets;
-    if (!dm.GetTableInfo(name, &old_targets)) {
+    if (!dm_.GetTableInfo(name, &old_targets)) {
         LOG(ERROR) << "Could not read snapshot device table: " << name;
         return MergeFailureCode::GetTableInfo;
     }
@@ -825,7 +817,7 @@
     DmTable table;
     table.Emplace<DmTargetSnapshot>(0, old_targets[0].spec.length, base_device, cow_device,
                                     SnapshotStorageMode::Merge, kSnapshotChunkSize);
-    if (!dm.LoadTableAndActivate(name, table)) {
+    if (!dm_.LoadTableAndActivate(name, table)) {
         LOG(ERROR) << "Could not swap device-mapper tables on snapshot device " << name;
         return MergeFailureCode::ActivateNewTable;
     }
@@ -833,24 +825,18 @@
     return MergeFailureCode::Ok;
 }
 
-enum class TableQuery {
-    Table,
-    Status,
-};
-
-static bool GetSingleTarget(const std::string& dm_name, TableQuery query,
-                            DeviceMapper::TargetInfo* target) {
-    auto& dm = DeviceMapper::Instance();
-    if (dm.GetState(dm_name) == DmDeviceState::INVALID) {
+bool SnapshotManager::GetSingleTarget(const std::string& dm_name, TableQuery query,
+                                      DeviceMapper::TargetInfo* target) {
+    if (dm_.GetState(dm_name) == DmDeviceState::INVALID) {
         return false;
     }
 
     std::vector<DeviceMapper::TargetInfo> targets;
     bool result;
     if (query == TableQuery::Status) {
-        result = dm.GetTableStatus(dm_name, &targets);
+        result = dm_.GetTableStatus(dm_name, &targets);
     } else {
-        result = dm.GetTableInfo(dm_name, &targets);
+        result = dm_.GetTableInfo(dm_name, &targets);
     }
     if (!result) {
         LOG(ERROR) << "Could not query device: " << dm_name;
@@ -1180,11 +1166,9 @@
         return MergeFailureCode::Ok;
     }
 
-    auto& dm = DeviceMapper::Instance();
-
     std::string cow_image_name = GetMappedCowDeviceName(name, status);
     std::string cow_image_path;
-    if (!dm.GetDmDevicePathByName(cow_image_name, &cow_image_path)) {
+    if (!dm_.GetDmDevicePathByName(cow_image_name, &cow_image_path)) {
         LOG(ERROR) << "Failed to get path for cow device: " << cow_image_name;
         return MergeFailureCode::GetCowPathConsistencyCheck;
     }
@@ -1360,8 +1344,6 @@
 
 bool SnapshotManager::CollapseSnapshotDevice(const std::string& name,
                                              const SnapshotStatus& status) {
-    auto& dm = DeviceMapper::Instance();
-
     // Verify we have a snapshot-merge device.
     DeviceMapper::TargetInfo target;
     if (!GetSingleTarget(name, TableQuery::Table, &target)) {
@@ -1400,7 +1382,7 @@
         return false;
     }
 
-    if (!dm.LoadTableAndActivate(name, table)) {
+    if (!dm_.LoadTableAndActivate(name, table)) {
         return false;
     }
 
@@ -1473,8 +1455,6 @@
         }
     }
 
-    auto& dm = DeviceMapper::Instance();
-
     auto lock = LockExclusive();
     if (!lock) return false;
 
@@ -1488,7 +1468,7 @@
     size_t ok_cows = 0;
     for (const auto& snapshot : snapshots) {
         std::string user_cow_name = GetDmUserCowName(snapshot);
-        if (dm.GetState(user_cow_name) == DmDeviceState::INVALID) {
+        if (dm_.GetState(user_cow_name) == DmDeviceState::INVALID) {
             continue;
         }
 
@@ -1515,7 +1495,7 @@
 
         DmTable table;
         table.Emplace<DmTargetUser>(0, target.spec.length, misc_name);
-        if (!dm.LoadTableAndActivate(user_cow_name, table)) {
+        if (!dm_.LoadTableAndActivate(user_cow_name, table)) {
             LOG(ERROR) << "Unable to swap tables for " << misc_name;
             continue;
         }
@@ -1528,7 +1508,7 @@
         }
 
         std::string source_device;
-        if (!dm.GetDmDevicePathByName(source_device_name, &source_device)) {
+        if (!dm_.GetDmDevicePathByName(source_device_name, &source_device)) {
             LOG(ERROR) << "Could not get device path for " << GetSourceDeviceName(snapshot);
             continue;
         }
@@ -1536,7 +1516,7 @@
         std::string cow_image_name = GetMappedCowDeviceName(snapshot, snapshot_status);
 
         std::string cow_image_device;
-        if (!dm.GetDmDevicePathByName(cow_image_name, &cow_image_device)) {
+        if (!dm_.GetDmDevicePathByName(cow_image_name, &cow_image_device)) {
             LOG(ERROR) << "Could not get device path for " << cow_image_name;
             continue;
         }
@@ -1711,8 +1691,7 @@
             // snapshot, but it's on the wrong slot. We can't unmap an active
             // partition. If this is not really a snapshot, skip the unmap
             // step.
-            auto& dm = DeviceMapper::Instance();
-            if (dm.GetState(name) == DmDeviceState::INVALID || !IsSnapshotDevice(name)) {
+            if (dm_.GetState(name) == DmDeviceState::INVALID || !IsSnapshotDevice(name)) {
                 LOG(ERROR) << "Detected snapshot " << name << " on " << current_slot << " slot"
                            << " for source partition; removing without unmap.";
                 should_unmap = false;
@@ -2049,14 +2028,13 @@
     // Create the base device for the snapshot, or if there is no snapshot, the
     // device itself. This device consists of the real blocks in the super
     // partition that this logical partition occupies.
-    auto& dm = DeviceMapper::Instance();
     std::string base_path;
     if (!CreateLogicalPartition(params, &base_path)) {
         LOG(ERROR) << "Could not create logical partition " << params.GetPartitionName()
                    << " as device " << params.GetDeviceName();
         return false;
     }
-    created_devices.EmplaceBack<AutoUnmapDevice>(&dm, params.GetDeviceName());
+    created_devices.EmplaceBack<AutoUnmapDevice>(&dm_, params.GetDeviceName());
 
     if (paths) {
         paths->target_device = base_path;
@@ -2070,7 +2048,7 @@
     // We don't have ueventd in first-stage init, so use device major:minor
     // strings instead.
     std::string base_device;
-    if (!dm.GetDeviceString(params.GetDeviceName(), &base_device)) {
+    if (!dm_.GetDeviceString(params.GetDeviceName(), &base_device)) {
         LOG(ERROR) << "Could not determine major/minor for: " << params.GetDeviceName();
         return false;
     }
@@ -2113,7 +2091,7 @@
             }
 
             auto source_device = GetSourceDeviceName(params.GetPartitionName());
-            created_devices.EmplaceBack<AutoUnmapDevice>(&dm, source_device);
+            created_devices.EmplaceBack<AutoUnmapDevice>(&dm_, source_device);
         } else {
             source_device_path = base_path;
         }
@@ -2140,7 +2118,7 @@
                        << params.GetPartitionName();
             return false;
         }
-        created_devices.EmplaceBack<AutoUnmapDevice>(&dm, name);
+        created_devices.EmplaceBack<AutoUnmapDevice>(&dm_, name);
 
         remaining_time = GetRemainingTime(params.timeout_ms, begin);
         if (remaining_time.count() < 0) return false;
@@ -2206,8 +2184,6 @@
     std::string cow_image_name = GetCowImageDeviceName(partition_name);
     *cow_name = GetCowName(partition_name);
 
-    auto& dm = DeviceMapper::Instance();
-
     // Map COW image if necessary.
     if (snapshot_status.cow_file_size() > 0) {
         if (!EnsureImageManager()) return false;
@@ -2258,11 +2234,11 @@
 
     // We have created the DmTable now. Map it.
     std::string cow_path;
-    if (!dm.CreateDevice(*cow_name, table, &cow_path, remaining_time)) {
+    if (!dm_.CreateDevice(*cow_name, table, &cow_path, remaining_time)) {
         LOG(ERROR) << "Could not create COW device: " << *cow_name;
         return false;
     }
-    created_devices->EmplaceBack<AutoUnmapDevice>(&dm, *cow_name);
+    created_devices->EmplaceBack<AutoUnmapDevice>(&dm_, *cow_name);
     LOG(INFO) << "Mapped COW device for " << params.GetPartitionName() << " at " << cow_path;
     return true;
 }
@@ -2289,10 +2265,8 @@
 }
 
 bool SnapshotManager::UnmapDmUserDevice(const std::string& snapshot_name) {
-    auto& dm = DeviceMapper::Instance();
-
     auto dm_user_name = GetDmUserCowName(snapshot_name);
-    if (dm.GetState(dm_user_name) == DmDeviceState::INVALID) {
+    if (dm_.GetState(dm_user_name) == DmDeviceState::INVALID) {
         return true;
     }
 
@@ -3512,7 +3486,6 @@
         return false;
     }
 
-    auto& dm = DeviceMapper::Instance();
     for (const auto& snapshot : snapshots) {
         SnapshotStatus status;
         if (!ReadSnapshotStatus(lock, snapshot, &status)) {
@@ -3523,7 +3496,7 @@
         }
 
         std::vector<DeviceMapper::TargetInfo> targets;
-        if (!dm.GetTableStatus(snapshot, &targets)) {
+        if (!dm_.GetTableStatus(snapshot, &targets)) {
             LOG(ERROR) << "Could not read snapshot device table: " << snapshot;
             return false;
         }
@@ -3616,11 +3589,9 @@
 // isn't running yet.
 bool SnapshotManager::GetMappedImageDevicePath(const std::string& device_name,
                                                std::string* device_path) {
-    auto& dm = DeviceMapper::Instance();
-
     // Try getting the device string if it is a device mapper device.
-    if (dm.GetState(device_name) != DmDeviceState::INVALID) {
-        return dm.GetDmDevicePathByName(device_name, device_path);
+    if (dm_.GetState(device_name) != DmDeviceState::INVALID) {
+        return dm_.GetDmDevicePathByName(device_name, device_path);
     }
 
     // Otherwise, get path from IImageManager.
@@ -3629,10 +3600,9 @@
 
 bool SnapshotManager::GetMappedImageDeviceStringOrPath(const std::string& device_name,
                                                        std::string* device_string_or_mapped_path) {
-    auto& dm = DeviceMapper::Instance();
     // Try getting the device string if it is a device mapper device.
-    if (dm.GetState(device_name) != DmDeviceState::INVALID) {
-        return dm.GetDeviceString(device_name, device_string_or_mapped_path);
+    if (dm_.GetState(device_name) != DmDeviceState::INVALID) {
+        return dm_.GetDeviceString(device_name, device_string_or_mapped_path);
     }
 
     // Otherwise, get path from IImageManager.
@@ -3748,10 +3718,9 @@
 
 bool SnapshotManager::DeleteDeviceIfExists(const std::string& name,
                                            const std::chrono::milliseconds& timeout_ms) {
-    auto& dm = DeviceMapper::Instance();
     auto start = std::chrono::steady_clock::now();
     while (true) {
-        if (dm.DeleteDeviceIfExists(name)) {
+        if (dm_.DeleteDeviceIfExists(name)) {
             return true;
         }
         auto now = std::chrono::steady_clock::now();
@@ -3764,7 +3733,7 @@
 
     // Try to diagnose why this failed. First get the actual device path.
     std::string full_path;
-    if (!dm.GetDmDevicePathByName(name, &full_path)) {
+    if (!dm_.GetDmDevicePathByName(name, &full_path)) {
         LOG(ERROR) << "Unable to diagnose DM_DEV_REMOVE failure.";
         return false;
     }
diff --git a/fs_mgr/libsnapshot/snapshot_fuzz_utils.h b/fs_mgr/libsnapshot/snapshot_fuzz_utils.h
index 3ed27c8..c1a5af7 100644
--- a/fs_mgr/libsnapshot/snapshot_fuzz_utils.h
+++ b/fs_mgr/libsnapshot/snapshot_fuzz_utils.h
@@ -101,7 +101,8 @@
         : env_(env),
           data_(&data),
           partition_opener_(std::move(partition_opener)),
-          metadata_dir_(metadata_dir) {}
+          metadata_dir_(metadata_dir),
+          dm_(android::dm::DeviceMapper::Instance()) {}
 
     // Following APIs are mocked.
     std::string GetMetadataDir() const override { return metadata_dir_; }
@@ -125,6 +126,7 @@
     }
     bool IsRecovery() const override { return data_->is_recovery(); }
     bool IsFirstStageInit() const override { return false; }
+    android::dm::IDeviceMapper& GetDeviceMapper() override { return dm_; }
     std::unique_ptr<IImageManager> OpenImageManager() const {
         return env_->CheckCreateFakeImageManager();
     }
@@ -137,6 +139,7 @@
     std::unique_ptr<TestPartitionOpener> partition_opener_;
     std::string metadata_dir_;
     bool switched_slot_ = false;
+    android::dm::DeviceMapper& dm_;
 
     bool CurrentSlotIsA() const { return data_->slot_suffix_is_a() != switched_slot_; }
 };
diff --git a/fs_mgr/libsnapshot/utility.h b/fs_mgr/libsnapshot/utility.h
index 671de9d..e97afed 100644
--- a/fs_mgr/libsnapshot/utility.h
+++ b/fs_mgr/libsnapshot/utility.h
@@ -57,14 +57,14 @@
 // Automatically unmap a device upon deletion.
 struct AutoUnmapDevice : AutoDevice {
     // On destruct, delete |name| from device mapper.
-    AutoUnmapDevice(android::dm::DeviceMapper* dm, const std::string& name)
+    AutoUnmapDevice(android::dm::IDeviceMapper* dm, const std::string& name)
         : AutoDevice(name), dm_(dm) {}
     AutoUnmapDevice(AutoUnmapDevice&& other) = default;
     ~AutoUnmapDevice();
 
   private:
     DISALLOW_COPY_AND_ASSIGN(AutoUnmapDevice);
-    android::dm::DeviceMapper* dm_ = nullptr;
+    android::dm::IDeviceMapper* dm_ = nullptr;
 };
 
 // Automatically unmap an image upon deletion.