diff --git a/Android.bp b/Android.bp
index c6f6251..0b4a925 100644
--- a/Android.bp
+++ b/Android.bp
@@ -2,5 +2,3 @@
     name: "android_filesystem_config_header",
     srcs: ["include/private/android_filesystem_config.h"],
 }
-
-subdirs = ["*"]
diff --git a/adb/Android.bp b/adb/Android.bp
index bd1f124..3e8da8a 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -217,6 +217,7 @@
         "libcutils",
         "libcrypto_utils",
         "libcrypto",
+        "liblog",
         "libmdnssd",
         "libdiagnose_usb",
         "libusb",
diff --git a/adb/adb.h b/adb/adb.h
index e7fcc91..7f7dd0d 100644
--- a/adb/adb.h
+++ b/adb/adb.h
@@ -185,14 +185,7 @@
     } while (0)
 #endif
 
-#if ADB_HOST_ON_TARGET
-/* adb and adbd are coexisting on the target, so use 5038 for adb
- * to avoid conflicting with adbd's usage of 5037
- */
-#define DEFAULT_ADB_PORT 5038
-#else
 #define DEFAULT_ADB_PORT 5037
-#endif
 
 #define DEFAULT_ADB_LOCAL_TRANSPORT_PORT 5555
 
diff --git a/adb/apex/ld.config.txt b/adb/apex/ld.config.txt
index 13d66b6..d1858a4 100644
--- a/adb/apex/ld.config.txt
+++ b/adb/apex/ld.config.txt
@@ -10,6 +10,8 @@
 namespace.default.isolated = true
 namespace.default.search.paths = /apex/com.android.adbd/${LIB}
 namespace.default.asan.search.paths = /apex/com.android.adbd/${LIB}
+namespace.default.permitted.paths = /system/${LIB}
+namespace.default.asan.permitted.paths = /system/${LIB}
 namespace.default.links = art,platform
 namespace.default.link.art.shared_libs = libadbconnection_server.so
 namespace.default.link.platform.shared_libs = libc.so:libdl.so:libm.so:libclang_rt.hwasan-aarch64-android.so
diff --git a/adb/client/commandline.cpp b/adb/client/commandline.cpp
index 813a8a9..83b9238 100644
--- a/adb/client/commandline.cpp
+++ b/adb/client/commandline.cpp
@@ -790,6 +790,15 @@
                        service_string);
 }
 
+static int adb_shell_noinput(int argc, const char** argv) {
+#if !defined(_WIN32)
+    unique_fd fd(adb_open("/dev/null", O_RDONLY));
+    CHECK_NE(STDIN_FILENO, fd.get());
+    dup2(fd.get(), STDIN_FILENO);
+#endif
+    return adb_shell(argc, argv);
+}
+
 static int adb_sideload_legacy(const char* filename, int in_fd, int size) {
     std::string error;
     unique_fd out_fd(adb_connect(android::base::StringPrintf("sideload:%d", size), &error));
@@ -1612,7 +1621,7 @@
         return adb_query_command(query);
     }
     else if (!strcmp(argv[0], "connect")) {
-        if (argc != 2) error_exit("usage: adb connect HOST[:PORT>]");
+        if (argc != 2) error_exit("usage: adb connect HOST[:PORT]");
 
         std::string query = android::base::StringPrintf("host:connect:%s", argv[1]);
         return adb_query_command(query);
@@ -1711,7 +1720,7 @@
         if (CanUseFeature(features, kFeatureRemountShell)) {
             std::vector<const char*> args = {"shell"};
             args.insert(args.cend(), argv, argv + argc);
-            return adb_shell(args.size(), args.data());
+            return adb_shell_noinput(args.size(), args.data());
         } else if (argc > 1) {
             auto command = android::base::StringPrintf("%s:%s", argv[0], argv[1]);
             return adb_connect_command(command);
diff --git a/base/include/android-base/logging.h b/base/include/android-base/logging.h
index ab6476c..3a9186a 100644
--- a/base/include/android-base/logging.h
+++ b/base/include/android-base/logging.h
@@ -116,7 +116,6 @@
 std::string GetDefaultTag();
 void SetDefaultTag(const std::string& tag);
 
-#ifdef __ANDROID__
 // We expose this even though it is the default because a user that wants to
 // override the default log buffer will have to construct this themselves.
 class LogdLogger {
@@ -129,7 +128,6 @@
  private:
   LogId default_log_id_;
 };
-#endif
 
 // Configure logging based on ANDROID_LOG_TAGS environment variable.
 // We need to parse a string that looks like
@@ -222,20 +220,16 @@
 // 1) This will not check whether the severity is high enough. One should use WOULD_LOG to filter
 //    usage manually.
 // 2) This does not save and restore errno.
-#define LOG_STREAM(severity) LOG_STREAM_TO(DEFAULT, severity)
-
-// Get an ostream that can be used for logging at the given severity and to the
-// given destination. The same notes as for LOG_STREAM apply.
-#define LOG_STREAM_TO(dest, severity)                                           \
-  ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::dest,        \
-                              SEVERITY_LAMBDA(severity), _LOG_TAG_INTERNAL, -1) \
+#define LOG_STREAM(severity)                                                                    \
+  ::android::base::LogMessage(__FILE__, __LINE__, SEVERITY_LAMBDA(severity), _LOG_TAG_INTERNAL, \
+                              -1)                                                               \
       .stream()
 
 // Logs a message to logcat on Android otherwise to stderr. If the severity is
 // FATAL it also causes an abort. For example:
 //
 //     LOG(FATAL) << "We didn't expect to reach here";
-#define LOG(severity) LOG_TO(DEFAULT, severity)
+#define LOG(severity) LOGGING_PREAMBLE(severity) && LOG_STREAM(severity)
 
 // Checks if we want to log something, and sets up appropriate RAII objects if
 // so.
@@ -245,21 +239,12 @@
    ABORT_AFTER_LOG_EXPR_IF((SEVERITY_LAMBDA(severity)) == ::android::base::FATAL, true) && \
    ::android::base::ErrnoRestorer())
 
-// Logs a message to logcat with the specified log ID on Android otherwise to
-// stderr. If the severity is FATAL it also causes an abort.
-// Use an expression here so we can support the << operator following the macro,
-// like "LOG(DEBUG) << xxx;".
-#define LOG_TO(dest, severity) LOGGING_PREAMBLE(severity) && LOG_STREAM_TO(dest, severity)
-
 // A variant of LOG that also logs the current errno value. To be used when
 // library calls fail.
-#define PLOG(severity) PLOG_TO(DEFAULT, severity)
-
-// Behaves like PLOG, but logs to the specified log ID.
-#define PLOG_TO(dest, severity)                                                        \
-  LOGGING_PREAMBLE(severity) &&                                                        \
-      ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::dest,           \
-                                  SEVERITY_LAMBDA(severity), _LOG_TAG_INTERNAL, errno) \
+#define PLOG(severity)                                                           \
+  LOGGING_PREAMBLE(severity) &&                                                  \
+      ::android::base::LogMessage(__FILE__, __LINE__, SEVERITY_LAMBDA(severity), \
+                                  _LOG_TAG_INTERNAL, errno)                      \
           .stream()
 
 // Marker that code is yet to be implemented.
@@ -272,24 +257,23 @@
 //
 //     CHECK(false == true) results in a log message of
 //       "Check failed: false == true".
-#define CHECK(x)                                                                 \
-  LIKELY((x)) || ABORT_AFTER_LOG_FATAL_EXPR(false) ||                            \
-      ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::DEFAULT,  \
-                                  ::android::base::FATAL, _LOG_TAG_INTERNAL, -1) \
-              .stream()                                                          \
+#define CHECK(x)                                                                                 \
+  LIKELY((x)) || ABORT_AFTER_LOG_FATAL_EXPR(false) ||                                            \
+      ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::FATAL, _LOG_TAG_INTERNAL, \
+                                  -1)                                                            \
+              .stream()                                                                          \
           << "Check failed: " #x << " "
 
 // clang-format off
 // Helper for CHECK_xx(x,y) macros.
-#define CHECK_OP(LHS, RHS, OP)                                                                 \
-  for (auto _values = ::android::base::MakeEagerEvaluator(LHS, RHS);                           \
-       UNLIKELY(!(_values.lhs OP _values.rhs));                                                \
-       /* empty */)                                                                            \
-  ABORT_AFTER_LOG_FATAL                                                                        \
-  ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::DEFAULT,                    \
-                              ::android::base::FATAL, _LOG_TAG_INTERNAL, -1)                   \
-          .stream()                                                                            \
-      << "Check failed: " << #LHS << " " << #OP << " " << #RHS << " (" #LHS "=" << _values.lhs \
+#define CHECK_OP(LHS, RHS, OP)                                                                   \
+  for (auto _values = ::android::base::MakeEagerEvaluator(LHS, RHS);                             \
+       UNLIKELY(!(_values.lhs OP _values.rhs));                                                  \
+       /* empty */)                                                                              \
+  ABORT_AFTER_LOG_FATAL                                                                          \
+  ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::FATAL, _LOG_TAG_INTERNAL, -1) \
+          .stream()                                                                              \
+      << "Check failed: " << #LHS << " " << #OP << " " << #RHS << " (" #LHS "=" << _values.lhs   \
       << ", " #RHS "=" << _values.rhs << ") "
 // clang-format on
 
@@ -311,8 +295,8 @@
 #define CHECK_STROP(s1, s2, sense)                                             \
   while (UNLIKELY((strcmp(s1, s2) == 0) != (sense)))                           \
     ABORT_AFTER_LOG_FATAL                                                      \
-    ::android::base::LogMessage(__FILE__, __LINE__, ::android::base::DEFAULT,  \
-                                ::android::base::FATAL, _LOG_TAG_INTERNAL, -1) \
+    ::android::base::LogMessage(__FILE__, __LINE__,  ::android::base::FATAL,   \
+                                 _LOG_TAG_INTERNAL, -1)                        \
         .stream()                                                              \
         << "Check failed: " << "\"" << (s1) << "\""                            \
         << ((sense) ? " == " : " != ") << "\"" << (s2) << "\""
@@ -431,8 +415,10 @@
 // of a CHECK. The destructor will abort if the severity is FATAL.
 class LogMessage {
  public:
-  LogMessage(const char* file, unsigned int line, LogId id, LogSeverity severity, const char* tag,
+  // LogId has been deprecated, but this constructor must exist for prebuilts.
+  LogMessage(const char* file, unsigned int line, LogId, LogSeverity severity, const char* tag,
              int error);
+  LogMessage(const char* file, unsigned int line, LogSeverity severity, const char* tag, int error);
 
   ~LogMessage();
 
@@ -441,8 +427,8 @@
   std::ostream& stream();
 
   // The routine that performs the actual logging.
-  static void LogLine(const char* file, unsigned int line, LogId id, LogSeverity severity,
-                      const char* tag, const char* msg);
+  static void LogLine(const char* file, unsigned int line, LogSeverity severity, const char* tag,
+                      const char* msg);
 
  private:
   const std::unique_ptr<LogMessageData> data_;
diff --git a/base/include/android-base/unique_fd.h b/base/include/android-base/unique_fd.h
index 1605daf..c4a0aad 100644
--- a/base/include/android-base/unique_fd.h
+++ b/base/include/android-base/unique_fd.h
@@ -116,6 +116,8 @@
   bool operator<(int rhs) const { return get() < rhs; }
   bool operator==(int rhs) const { return get() == rhs; }
   bool operator!=(int rhs) const { return get() != rhs; }
+  bool operator==(const unique_fd_impl& rhs) const { return get() == rhs.get(); }
+  bool operator!=(const unique_fd_impl& rhs) const { return get() != rhs.get(); }
 
   // Catch bogus error checks (i.e.: "!fd" instead of "fd != -1").
   bool operator!() const = delete;
diff --git a/base/logging.cpp b/base/logging.cpp
index f89168c..b46abbf 100644
--- a/base/logging.cpp
+++ b/base/logging.cpp
@@ -45,8 +45,8 @@
 #include <vector>
 
 // Headers for LogMessage::LogLine.
-#ifdef __ANDROID__
 #include <android/log.h>
+#ifdef __ANDROID__
 #include <android/set_abort_message.h>
 #else
 #include <sys/types.h>
@@ -242,7 +242,6 @@
 }
 
 
-#ifdef __ANDROID__
 LogdLogger::LogdLogger(LogId default_log_id) : default_log_id_(default_log_id) {
 }
 
@@ -276,7 +275,6 @@
     __android_log_buf_print(lg_id, priority, tag, "%s", message);
   }
 }
-#endif
 
 void InitLogging(char* argv[], LogFunction&& logger, AbortFunction&& aborter) {
   SetLogger(std::forward<LogFunction>(logger));
@@ -350,11 +348,10 @@
 // checks/logging in a function.
 class LogMessageData {
  public:
-  LogMessageData(const char* file, unsigned int line, LogId id, LogSeverity severity,
-                 const char* tag, int error)
+  LogMessageData(const char* file, unsigned int line, LogSeverity severity, const char* tag,
+                 int error)
       : file_(GetFileBasename(file)),
         line_number_(line),
-        id_(id),
         severity_(severity),
         tag_(tag),
         error_(error) {}
@@ -373,10 +370,6 @@
 
   const char* GetTag() const { return tag_; }
 
-  LogId GetId() const {
-    return id_;
-  }
-
   int GetError() const {
     return error_;
   }
@@ -393,7 +386,6 @@
   std::ostringstream buffer_;
   const char* const file_;
   const unsigned int line_number_;
-  const LogId id_;
   const LogSeverity severity_;
   const char* const tag_;
   const int error_;
@@ -401,9 +393,13 @@
   DISALLOW_COPY_AND_ASSIGN(LogMessageData);
 };
 
-LogMessage::LogMessage(const char* file, unsigned int line, LogId id, LogSeverity severity,
+LogMessage::LogMessage(const char* file, unsigned int line, LogId, LogSeverity severity,
                        const char* tag, int error)
-    : data_(new LogMessageData(file, line, id, severity, tag, error)) {}
+    : LogMessage(file, line, severity, tag, error) {}
+
+LogMessage::LogMessage(const char* file, unsigned int line, LogSeverity severity, const char* tag,
+                       int error)
+    : data_(new LogMessageData(file, line, severity, tag, error)) {}
 
 LogMessage::~LogMessage() {
   // Check severity again. This is duplicate work wrt/ LOG macros, but not LOG_STREAM.
@@ -429,16 +425,16 @@
     // Do the actual logging with the lock held.
     std::lock_guard<std::mutex> lock(LoggingLock());
     if (msg.find('\n') == std::string::npos) {
-      LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetId(), data_->GetSeverity(),
-              data_->GetTag(), msg.c_str());
+      LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetSeverity(), data_->GetTag(),
+              msg.c_str());
     } else {
       msg += '\n';
       size_t i = 0;
       while (i < msg.size()) {
         size_t nl = msg.find('\n', i);
         msg[nl] = '\0';
-        LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetId(), data_->GetSeverity(),
-                data_->GetTag(), &msg[i]);
+        LogLine(data_->GetFile(), data_->GetLineNumber(), data_->GetSeverity(), data_->GetTag(),
+                &msg[i]);
         // Undo the zero-termination so we can give the complete message to the aborter.
         msg[nl] = '\n';
         i = nl + 1;
@@ -456,16 +452,16 @@
   return data_->GetBuffer();
 }
 
-void LogMessage::LogLine(const char* file, unsigned int line, LogId id, LogSeverity severity,
-                         const char* tag, const char* message) {
+void LogMessage::LogLine(const char* file, unsigned int line, LogSeverity severity, const char* tag,
+                         const char* message) {
   if (tag == nullptr) {
     std::lock_guard<std::recursive_mutex> lock(TagLock());
     if (gDefaultTag == nullptr) {
       gDefaultTag = new std::string(getprogname());
     }
-    Logger()(id, severity, gDefaultTag->c_str(), file, line, message);
+    Logger()(DEFAULT, severity, gDefaultTag->c_str(), file, line, message);
   } else {
-    Logger()(id, severity, tag, file, line, message);
+    Logger()(DEFAULT, severity, tag, file, line, message);
   }
 }
 
diff --git a/debuggerd/Android.bp b/debuggerd/Android.bp
index 780e48d..c8df3e3 100644
--- a/debuggerd/Android.bp
+++ b/debuggerd/Android.bp
@@ -355,7 +355,3 @@
 
     init_rc: ["tombstoned/tombstoned.rc"],
 }
-
-subdirs = [
-    "crasher",
-]
diff --git a/deprecated-adf/Android.bp b/deprecated-adf/Android.bp
deleted file mode 100644
index b44c296..0000000
--- a/deprecated-adf/Android.bp
+++ /dev/null
@@ -1 +0,0 @@
-subdirs = ["*"]
diff --git a/deprecated-adf/libadf/Android.bp b/deprecated-adf/libadf/Android.bp
index 49e3721..70f0a3b 100644
--- a/deprecated-adf/libadf/Android.bp
+++ b/deprecated-adf/libadf/Android.bp
@@ -24,5 +24,3 @@
     local_include_dirs: ["include"],
     export_include_dirs: ["include"],
 }
-
-subdirs = ["tests"]
diff --git a/fastboot/device/commands.cpp b/fastboot/device/commands.cpp
index 1a745ab..b7263d9 100644
--- a/fastboot/device/commands.cpp
+++ b/fastboot/device/commands.cpp
@@ -31,7 +31,6 @@
 #include <cutils/android_reboot.h>
 #include <ext4_utils/wipe.h>
 #include <fs_mgr.h>
-#include <fs_mgr/roots.h>
 #include <libgsi/libgsi.h>
 #include <liblp/builder.h>
 #include <liblp/liblp.h>
@@ -550,42 +549,6 @@
     return UpdateSuper(device, args[1], wipe);
 }
 
-class AutoMountMetadata {
-  public:
-    AutoMountMetadata() {
-        android::fs_mgr::Fstab proc_mounts;
-        if (!ReadFstabFromFile("/proc/mounts", &proc_mounts)) {
-            LOG(ERROR) << "Could not read /proc/mounts";
-            return;
-        }
-
-        auto iter = std::find_if(proc_mounts.begin(), proc_mounts.end(),
-                [](const auto& entry) { return entry.mount_point == "/metadata"; });
-        if (iter != proc_mounts.end()) {
-            mounted_ = true;
-            return;
-        }
-
-        if (!ReadDefaultFstab(&fstab_)) {
-            LOG(ERROR) << "Could not read default fstab";
-            return;
-        }
-        mounted_ = EnsurePathMounted(&fstab_, "/metadata");
-        should_unmount_ = true;
-    }
-    ~AutoMountMetadata() {
-        if (mounted_ && should_unmount_) {
-            EnsurePathUnmounted(&fstab_, "/metadata");
-        }
-    }
-    explicit operator bool() const { return mounted_; }
-
-  private:
-    android::fs_mgr::Fstab fstab_;
-    bool mounted_ = false;
-    bool should_unmount_ = false;
-};
-
 bool GsiHandler(FastbootDevice* device, const std::vector<std::string>& args) {
     if (args.size() != 2) {
         return device->WriteFail("Invalid arguments");
diff --git a/fastboot/device/flashing.cpp b/fastboot/device/flashing.cpp
index 102ebdb..7e7e507 100644
--- a/fastboot/device/flashing.cpp
+++ b/fastboot/device/flashing.cpp
@@ -21,6 +21,7 @@
 
 #include <algorithm>
 #include <memory>
+#include <optional>
 #include <set>
 #include <string>
 
@@ -56,6 +57,7 @@
     Fstab fstab;
     ReadDefaultFstab(&fstab);
 
+    std::optional<AutoMountMetadata> mount_metadata;
     for (const auto& entry : fstab) {
         auto partition = android::base::Basename(entry.mount_point);
         if ("/" == entry.mount_point) {
@@ -63,6 +65,7 @@
         }
 
         if ((partition + device->GetCurrentSlot()) == partition_name) {
+            mount_metadata.emplace();
             fs_mgr_overlayfs_teardown(entry.mount_point.c_str());
         }
     }
diff --git a/fastboot/device/utility.cpp b/fastboot/device/utility.cpp
index b3f2d5f..7c6ac89 100644
--- a/fastboot/device/utility.cpp
+++ b/fastboot/device/utility.cpp
@@ -26,6 +26,7 @@
 #include <android-base/properties.h>
 #include <android-base/strings.h>
 #include <fs_mgr.h>
+#include <fs_mgr/roots.h>
 #include <fs_mgr_dm_linear.h>
 #include <liblp/builder.h>
 #include <liblp/liblp.h>
@@ -240,3 +241,29 @@
     }
     return current_slot_suffix;
 }
+
+AutoMountMetadata::AutoMountMetadata() {
+    android::fs_mgr::Fstab proc_mounts;
+    if (!ReadFstabFromFile("/proc/mounts", &proc_mounts)) {
+        LOG(ERROR) << "Could not read /proc/mounts";
+        return;
+    }
+
+    if (GetEntryForMountPoint(&proc_mounts, "/metadata")) {
+        mounted_ = true;
+        return;
+    }
+
+    if (!ReadDefaultFstab(&fstab_)) {
+        LOG(ERROR) << "Could not read default fstab";
+        return;
+    }
+    mounted_ = EnsurePathMounted(&fstab_, "/metadata");
+    should_unmount_ = true;
+}
+
+AutoMountMetadata::~AutoMountMetadata() {
+    if (mounted_ && should_unmount_) {
+        EnsurePathUnmounted(&fstab_, "/metadata");
+    }
+}
diff --git a/fastboot/device/utility.h b/fastboot/device/utility.h
index bfeeb74..3b71ef0 100644
--- a/fastboot/device/utility.h
+++ b/fastboot/device/utility.h
@@ -20,6 +20,7 @@
 
 #include <android-base/unique_fd.h>
 #include <android/hardware/boot/1.0/IBootControl.h>
+#include <fstab/fstab.h>
 #include <liblp/liblp.h>
 
 // Logical partitions are only mapped to a block device as needed, and
@@ -51,6 +52,18 @@
     std::function<void()> closer_;
 };
 
+class AutoMountMetadata {
+  public:
+    AutoMountMetadata();
+    ~AutoMountMetadata();
+    explicit operator bool() const { return mounted_; }
+
+  private:
+    android::fs_mgr::Fstab fstab_;
+    bool mounted_ = false;
+    bool should_unmount_ = false;
+};
+
 class FastbootDevice;
 
 // On normal devices, the super partition is always named "super". On retrofit
diff --git a/fastboot/fuzzy_fastboot/Android.bp b/fastboot/fuzzy_fastboot/Android.bp
index 277cc3a..d48cfa9 100644
--- a/fastboot/fuzzy_fastboot/Android.bp
+++ b/fastboot/fuzzy_fastboot/Android.bp
@@ -31,6 +31,8 @@
     "libext4_utils",
   ],
 
+  stl: "libc++_static",
+
   // Static libs (libfastboot2) shared library dependencies are not transitively included
   // This is needed to avoid link time errors when building for mac
   target: {
@@ -40,5 +42,13 @@
           "-framework IOKit",
       ],
     },
-  }
+  },
+
+  // Disable auto-generation of test config as this binary itself is not a test in the test suites,
+  // rather it is used by other tests.
+  auto_gen_config: false,
+  test_suites: [
+    "general-tests",
+    "vts-core",
+  ],
 }
diff --git a/fs_mgr/fs_mgr.cpp b/fs_mgr/fs_mgr.cpp
index 15c9dfb..03c7943 100644
--- a/fs_mgr/fs_mgr.cpp
+++ b/fs_mgr/fs_mgr.cpp
@@ -910,6 +910,10 @@
     return true;
 }
 
+static bool SupportsCheckpoint(FstabEntry* entry) {
+    return entry->fs_mgr_flags.checkpoint_blk || entry->fs_mgr_flags.checkpoint_fs;
+}
+
 class CheckpointManager {
   public:
     CheckpointManager(int needs_checkpoint = -1) : needs_checkpoint_(needs_checkpoint) {}
@@ -926,7 +930,7 @@
     }
 
     bool Update(FstabEntry* entry, const std::string& block_device = std::string()) {
-        if (!entry->fs_mgr_flags.checkpoint_blk && !entry->fs_mgr_flags.checkpoint_fs) {
+        if (!SupportsCheckpoint(entry)) {
             return true;
         }
 
@@ -947,7 +951,7 @@
     }
 
     bool Revert(FstabEntry* entry) {
-        if (!entry->fs_mgr_flags.checkpoint_blk && !entry->fs_mgr_flags.checkpoint_fs) {
+        if (!SupportsCheckpoint(entry)) {
             return true;
         }
 
@@ -1362,6 +1366,7 @@
 }
 
 static bool fs_mgr_unmount_all_data_mounts(const std::string& block_device) {
+    LINFO << __FUNCTION__ << "(): about to umount everything on top of " << block_device;
     Timer t;
     // TODO(b/135984674): should be configured via a read-only property.
     std::chrono::milliseconds timeout = 5s;
@@ -1369,22 +1374,34 @@
         bool umount_done = true;
         Fstab proc_mounts;
         if (!ReadFstabFromFile("/proc/mounts", &proc_mounts)) {
-            LERROR << "Can't read /proc/mounts";
+            LERROR << __FUNCTION__ << "(): Can't read /proc/mounts";
             return false;
         }
         // Now proceed with other bind mounts on top of /data.
         for (const auto& entry : proc_mounts) {
             if (entry.blk_device == block_device) {
                 if (umount2(entry.mount_point.c_str(), 0) != 0) {
+                    PERROR << __FUNCTION__ << "(): Failed to umount " << entry.mount_point;
                     umount_done = false;
                 }
             }
         }
         if (umount_done) {
-            LINFO << "Unmounting /data took " << t;
+            LINFO << __FUNCTION__ << "(): Unmounting /data took " << t;
             return true;
         }
         if (t.duration() > timeout) {
+            LERROR << __FUNCTION__ << "(): Timed out unmounting all mounts on " << block_device;
+            Fstab remaining_mounts;
+            if (!ReadFstabFromFile("/proc/mounts", &remaining_mounts)) {
+                LERROR << __FUNCTION__ << "(): Can't read /proc/mounts";
+            } else {
+                LERROR << __FUNCTION__ << "(): Following mounts remaining";
+                for (const auto& e : remaining_mounts) {
+                    LERROR << __FUNCTION__ << "(): mount point: " << e.mount_point
+                           << " block device: " << e.blk_device;
+                }
+            }
             return false;
         }
         std::this_thread::sleep_for(50ms);
@@ -1410,18 +1427,20 @@
         LERROR << "Can't find /data in fstab";
         return -1;
     }
-    if (!fstab_entry->fs_mgr_flags.checkpoint_blk && !fstab_entry->fs_mgr_flags.checkpoint_fs) {
+    bool force_umount = GetBoolProperty("sys.init.userdata_remount.force_umount", false);
+    if (force_umount) {
+        LINFO << "Will force an umount of userdata even if it's not required";
+    }
+    if (!force_umount && !SupportsCheckpoint(fstab_entry)) {
         LINFO << "Userdata doesn't support checkpointing. Nothing to do";
         return 0;
     }
     CheckpointManager checkpoint_manager;
-    if (!checkpoint_manager.NeedsCheckpoint()) {
+    if (!force_umount && !checkpoint_manager.NeedsCheckpoint()) {
         LINFO << "Checkpointing not needed. Don't remount";
         return 0;
     }
-    bool force_umount_for_f2fs =
-            GetBoolProperty("sys.init.userdata_remount.force_umount_f2fs", false);
-    if (fstab_entry->fs_mgr_flags.checkpoint_fs && !force_umount_for_f2fs) {
+    if (!force_umount && fstab_entry->fs_mgr_flags.checkpoint_fs) {
         // Userdata is f2fs, simply remount it.
         if (!checkpoint_manager.Update(fstab_entry)) {
             LERROR << "Failed to remount userdata in checkpointing mode";
diff --git a/fs_mgr/libfiemap/Android.bp b/fs_mgr/libfiemap/Android.bp
index fdc1583..1bf457f 100644
--- a/fs_mgr/libfiemap/Android.bp
+++ b/fs_mgr/libfiemap/Android.bp
@@ -24,6 +24,7 @@
     name: "libfiemap_srcs",
     srcs: [
         "fiemap_writer.cpp",
+        "fiemap_status.cpp",
         "image_manager.cpp",
         "metadata.cpp",
         "split_fiemap_writer.cpp",
@@ -78,6 +79,11 @@
     srcs: [
         "fiemap_writer_test.cpp",
     ],
+
+    test_suites: ["vts-core", "device-tests"],
+    auto_gen_config: true,
+    test_min_api_level: 29,
+    require_root: true,
 }
 
 cc_test {
@@ -99,7 +105,3 @@
         "image_test.cpp",
     ],
 }
-
-vts_config {
-    name: "VtsFiemapWriterTest",
-}
diff --git a/fs_mgr/libfiemap/AndroidTest.xml b/fs_mgr/libfiemap/AndroidTest.xml
deleted file mode 100644
index 44c80fc..0000000
--- a/fs_mgr/libfiemap/AndroidTest.xml
+++ /dev/null
@@ -1,30 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (C) 2019 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 for VTS VtsFiemapWriterTest">
-    <option name="config-descriptor:metadata" key="plan" value="vts-kernel" />
-    <target_preparer class="com.android.compatibility.common.tradefed.targetprep.VtsFilePusher">
-        <option name="abort-on-push-failure" value="false"/>
-        <option name="push-group" value="HostDrivenTest.push"/>
-    </target_preparer>
-    <test class="com.android.tradefed.testtype.VtsMultiDeviceTest">
-      <option name="test-module-name" value="VtsFiemapWriterTest"/>
-        <option name="binary-test-source" value="_32bit::DATA/nativetest/fiemap_writer_test/fiemap_writer_test" />
-        <option name="binary-test-source" value="_64bit::DATA/nativetest64/fiemap_writer_test/fiemap_writer_test" />
-        <option name="binary-test-type" value="gtest"/>
-        <option name="precondition-first-api-level" value="29" />
-        <option name="test-timeout" value="1m"/>
-    </test>
-</configuration>
diff --git a/fs_mgr/libfiemap/binder.cpp b/fs_mgr/libfiemap/binder.cpp
index f99055a..96c36ed 100644
--- a/fs_mgr/libfiemap/binder.cpp
+++ b/fs_mgr/libfiemap/binder.cpp
@@ -17,6 +17,7 @@
 #if !defined(__ANDROID_RECOVERY__)
 #include <android-base/logging.h>
 #include <android-base/properties.h>
+#include <android/gsi/BnProgressCallback.h>
 #include <android/gsi/IGsiService.h>
 #include <android/gsi/IGsid.h>
 #include <binder/IServiceManager.h>
@@ -29,10 +30,29 @@
 using namespace android::gsi;
 using namespace std::chrono_literals;
 
+class ProgressCallback final : public BnProgressCallback {
+  public:
+    ProgressCallback(std::function<bool(uint64_t, uint64_t)>&& callback)
+        : callback_(std::move(callback)) {
+        CHECK(callback_);
+    }
+    android::binder::Status onProgress(int64_t current, int64_t total) {
+        if (callback_(static_cast<uint64_t>(current), static_cast<uint64_t>(total))) {
+            return android::binder::Status::ok();
+        }
+        return android::binder::Status::fromServiceSpecificError(UNKNOWN_ERROR,
+                                                                 "Progress callback failed");
+    }
+
+  private:
+    std::function<bool(uint64_t, uint64_t)> callback_;
+};
+
 class ImageManagerBinder final : public IImageManager {
   public:
     ImageManagerBinder(android::sp<IGsiService>&& service, android::sp<IImageService>&& manager);
-    bool CreateBackingImage(const std::string& name, uint64_t size, int flags) override;
+    FiemapStatus CreateBackingImage(const std::string& name, uint64_t size, int flags,
+                                    std::function<bool(uint64_t, uint64_t)>&& on_progress) override;
     bool DeleteBackingImage(const std::string& name) override;
     bool MapImageDevice(const std::string& name, const std::chrono::milliseconds& timeout_ms,
                         std::string* path) override;
@@ -41,7 +61,7 @@
     bool IsImageMapped(const std::string& name) override;
     bool MapImageWithDeviceMapper(const IPartitionOpener& opener, const std::string& name,
                                   std::string* dev) override;
-    bool ZeroFillNewImage(const std::string& name, uint64_t bytes) override;
+    FiemapStatus ZeroFillNewImage(const std::string& name, uint64_t bytes) override;
     bool RemoveAllImages() override;
     bool DisableImage(const std::string& name) override;
     bool RemoveDisabledImages() override;
@@ -55,18 +75,31 @@
     android::sp<IImageService> manager_;
 };
 
+static FiemapStatus ToFiemapStatus(const char* func, const binder::Status& status) {
+    if (!status.isOk()) {
+        LOG(ERROR) << func << " binder returned: " << status.toString8().string();
+        if (status.serviceSpecificErrorCode() != 0) {
+            return FiemapStatus::FromErrorCode(status.serviceSpecificErrorCode());
+        } else {
+            return FiemapStatus::Error();
+        }
+    }
+    return FiemapStatus::Ok();
+}
+
 ImageManagerBinder::ImageManagerBinder(android::sp<IGsiService>&& service,
                                        android::sp<IImageService>&& manager)
     : service_(std::move(service)), manager_(std::move(manager)) {}
 
-bool ImageManagerBinder::CreateBackingImage(const std::string& name, uint64_t size, int flags) {
-    auto status = manager_->createBackingImage(name, size, flags);
-    if (!status.isOk()) {
-        LOG(ERROR) << __PRETTY_FUNCTION__
-                   << " binder returned: " << status.exceptionMessage().string();
-        return false;
+FiemapStatus ImageManagerBinder::CreateBackingImage(
+        const std::string& name, uint64_t size, int flags,
+        std::function<bool(uint64_t, uint64_t)>&& on_progress) {
+    sp<IProgressCallback> callback = nullptr;
+    if (on_progress) {
+        callback = new ProgressCallback(std::move(on_progress));
     }
-    return true;
+    auto status = manager_->createBackingImage(name, size, flags, callback);
+    return ToFiemapStatus(__PRETTY_FUNCTION__, status);
 }
 
 bool ImageManagerBinder::DeleteBackingImage(const std::string& name) {
@@ -147,14 +180,9 @@
     return retval;
 }
 
-bool ImageManagerBinder::ZeroFillNewImage(const std::string& name, uint64_t bytes) {
+FiemapStatus ImageManagerBinder::ZeroFillNewImage(const std::string& name, uint64_t bytes) {
     auto status = manager_->zeroFillNewImage(name, bytes);
-    if (!status.isOk()) {
-        LOG(ERROR) << __PRETTY_FUNCTION__
-                   << " binder returned: " << status.exceptionMessage().string();
-        return false;
-    }
-    return true;
+    return ToFiemapStatus(__PRETTY_FUNCTION__, status);
 }
 
 bool ImageManagerBinder::RemoveAllImages() {
diff --git a/fs_mgr/libfiemap/fiemap_status.cpp b/fs_mgr/libfiemap/fiemap_status.cpp
new file mode 100644
index 0000000..92ac935
--- /dev/null
+++ b/fs_mgr/libfiemap/fiemap_status.cpp
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2019 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 <libfiemap/fiemap_status.h>
+
+namespace android::fiemap {
+
+// FiemapStatus -> string
+std::string FiemapStatus::string() const {
+    if (error_code() == ErrorCode::ERROR) {
+        return "Error";
+    }
+    return strerror(-static_cast<int>(error_code()));
+}
+
+// -errno -> known ErrorCode
+// unknown ErrorCode -> known ErrorCode
+FiemapStatus::ErrorCode FiemapStatus::CastErrorCode(int error_code) {
+    switch (error_code) {
+        case static_cast<int32_t>(ErrorCode::SUCCESS):
+        case static_cast<int32_t>(ErrorCode::NO_SPACE):
+            return static_cast<ErrorCode>(error_code);
+        case static_cast<int32_t>(ErrorCode::ERROR):
+        default:
+            return ErrorCode::ERROR;
+    }
+}
+
+}  // namespace android::fiemap
diff --git a/fs_mgr/libfiemap/fiemap_writer.cpp b/fs_mgr/libfiemap/fiemap_writer.cpp
index d34e0b8..b911234 100644
--- a/fs_mgr/libfiemap/fiemap_writer.cpp
+++ b/fs_mgr/libfiemap/fiemap_writer.cpp
@@ -262,9 +262,9 @@
     return true;
 }
 
-static bool FallocateFallback(int file_fd, uint64_t block_size, uint64_t file_size,
-                              const std::string& file_path,
-                              const std::function<bool(uint64_t, uint64_t)>& on_progress) {
+static FiemapStatus FallocateFallback(int file_fd, uint64_t block_size, uint64_t file_size,
+                                      const std::string& file_path,
+                                      const std::function<bool(uint64_t, uint64_t)>& on_progress) {
     // Even though this is much faster than writing zeroes, it is still slow
     // enough that we need to fire the progress callback periodically. To
     // easily achieve this, we seek in chunks. We use 1000 chunks since
@@ -280,22 +280,22 @@
         auto rv = TEMP_FAILURE_RETRY(lseek(file_fd, cursor - 1, SEEK_SET));
         if (rv < 0) {
             PLOG(ERROR) << "Failed to lseek " << file_path;
-            return false;
+            return FiemapStatus::FromErrno(errno);
         }
         if (rv != cursor - 1) {
             LOG(ERROR) << "Seek returned wrong offset " << rv << " for file " << file_path;
-            return false;
+            return FiemapStatus::Error();
         }
         char buffer[] = {0};
         if (!android::base::WriteFully(file_fd, buffer, 1)) {
             PLOG(ERROR) << "Write failed: " << file_path;
-            return false;
+            return FiemapStatus::FromErrno(errno);
         }
         if (on_progress && !on_progress(cursor, file_size)) {
-            return false;
+            return FiemapStatus::Error();
         }
     }
-    return true;
+    return FiemapStatus::Ok();
 }
 
 // F2FS-specific ioctl
@@ -382,19 +382,19 @@
 // write zeroes in 'blocksz' byte increments until we reach file_size to make sure the data
 // blocks are actually written to by the file system and thus getting rid of the holes in the
 // file.
-static bool WriteZeroes(int file_fd, const std::string& file_path, size_t blocksz,
-                        uint64_t file_size,
-                        const std::function<bool(uint64_t, uint64_t)>& on_progress) {
+static FiemapStatus WriteZeroes(int file_fd, const std::string& file_path, size_t blocksz,
+                                uint64_t file_size,
+                                const std::function<bool(uint64_t, uint64_t)>& on_progress) {
     auto buffer = std::unique_ptr<void, decltype(&free)>(calloc(1, blocksz), free);
     if (buffer == nullptr) {
         LOG(ERROR) << "failed to allocate memory for writing file";
-        return false;
+        return FiemapStatus::Error();
     }
 
     off64_t offset = lseek64(file_fd, 0, SEEK_SET);
     if (offset < 0) {
         PLOG(ERROR) << "Failed to seek at the beginning of : " << file_path;
-        return false;
+        return FiemapStatus::FromErrno(errno);
     }
 
     int permille = -1;
@@ -402,7 +402,7 @@
         if (!::android::base::WriteFully(file_fd, buffer.get(), blocksz)) {
             PLOG(ERROR) << "Failed to write" << blocksz << " bytes at offset" << offset
                         << " in file " << file_path;
-            return false;
+            return FiemapStatus::FromErrno(errno);
         }
 
         offset += blocksz;
@@ -412,7 +412,7 @@
         int new_permille = (static_cast<uint64_t>(offset) * 1000) / file_size;
         if (new_permille != permille && static_cast<uint64_t>(offset) != file_size) {
             if (on_progress && !on_progress(offset, file_size)) {
-                return false;
+                return FiemapStatus::Error();
             }
             permille = new_permille;
         }
@@ -420,18 +420,18 @@
 
     if (lseek64(file_fd, 0, SEEK_SET) < 0) {
         PLOG(ERROR) << "Failed to reset offset at the beginning of : " << file_path;
-        return false;
+        return FiemapStatus::FromErrno(errno);
     }
-    return true;
+    return FiemapStatus::Ok();
 }
 
 // Reserve space for the file on the file system and write it out to make sure the extents
 // don't come back unwritten. Return from this function with the kernel file offset set to 0.
 // If the filesystem is f2fs, then we also PIN the file on disk to make sure the blocks
 // aren't moved around.
-static bool AllocateFile(int file_fd, const std::string& file_path, uint64_t blocksz,
-                         uint64_t file_size, unsigned int fs_type,
-                         std::function<bool(uint64_t, uint64_t)> on_progress) {
+static FiemapStatus AllocateFile(int file_fd, const std::string& file_path, uint64_t blocksz,
+                                 uint64_t file_size, unsigned int fs_type,
+                                 std::function<bool(uint64_t, uint64_t)> on_progress) {
     bool need_explicit_writes = true;
     switch (fs_type) {
         case EXT4_SUPER_MAGIC:
@@ -439,11 +439,11 @@
         case F2FS_SUPER_MAGIC: {
             bool supported;
             if (!F2fsPinBeforeAllocate(file_fd, &supported)) {
-                return false;
+                return FiemapStatus::Error();
             }
             if (supported) {
                 if (!PinFile(file_fd, file_path, fs_type)) {
-                    return false;
+                    return FiemapStatus::Error();
                 }
                 need_explicit_writes = false;
             }
@@ -455,29 +455,32 @@
             return FallocateFallback(file_fd, blocksz, file_size, file_path, on_progress);
         default:
             LOG(ERROR) << "Missing fallocate() support for file system " << fs_type;
-            return false;
+            return FiemapStatus::Error();
     }
 
     if (fallocate(file_fd, 0, 0, file_size)) {
         PLOG(ERROR) << "Failed to allocate space for file: " << file_path << " size: " << file_size;
-        return false;
+        return FiemapStatus::FromErrno(errno);
     }
 
-    if (need_explicit_writes && !WriteZeroes(file_fd, file_path, blocksz, file_size, on_progress)) {
-        return false;
+    if (need_explicit_writes) {
+        auto status = WriteZeroes(file_fd, file_path, blocksz, file_size, on_progress);
+        if (!status.is_ok()) {
+            return status;
+        }
     }
 
     // flush all writes here ..
     if (fsync(file_fd)) {
         PLOG(ERROR) << "Failed to synchronize written file:" << file_path;
-        return false;
+        return FiemapStatus::FromErrno(errno);
     }
 
     // Send one last progress notification.
     if (on_progress && !on_progress(file_size, file_size)) {
-        return false;
+        return FiemapStatus::Error();
     }
-    return true;
+    return FiemapStatus::Ok();
 }
 
 bool FiemapWriter::HasPinnedExtents(const std::string& file_path) {
@@ -671,6 +674,18 @@
 
 FiemapUniquePtr FiemapWriter::Open(const std::string& file_path, uint64_t file_size, bool create,
                                    std::function<bool(uint64_t, uint64_t)> progress) {
+    FiemapUniquePtr ret;
+    if (!Open(file_path, file_size, &ret, create, progress).is_ok()) {
+        return nullptr;
+    }
+    return ret;
+}
+
+FiemapStatus FiemapWriter::Open(const std::string& file_path, uint64_t file_size,
+                                FiemapUniquePtr* out, bool create,
+                                std::function<bool(uint64_t, uint64_t)> progress) {
+    out->reset();
+
     // if 'create' is false, open an existing file and do not truncate.
     int open_flags = O_RDWR | O_CLOEXEC;
     if (create) {
@@ -683,43 +698,46 @@
             TEMP_FAILURE_RETRY(open(file_path.c_str(), open_flags, S_IRUSR | S_IWUSR)));
     if (file_fd < 0) {
         PLOG(ERROR) << "Failed to create file at: " << file_path;
-        return nullptr;
+        return FiemapStatus::FromErrno(errno);
     }
 
     std::string abs_path;
     if (!::android::base::Realpath(file_path, &abs_path)) {
+        int saved_errno = errno;
         PLOG(ERROR) << "Invalid file path: " << file_path;
         cleanup(file_path, create);
-        return nullptr;
+        return FiemapStatus::FromErrno(saved_errno);
     }
 
     std::string bdev_path;
     if (!GetBlockDeviceForFile(abs_path, &bdev_path)) {
         LOG(ERROR) << "Failed to get block dev path for file: " << file_path;
         cleanup(abs_path, create);
-        return nullptr;
+        return FiemapStatus::Error();
     }
 
     ::android::base::unique_fd bdev_fd(
             TEMP_FAILURE_RETRY(open(bdev_path.c_str(), O_RDONLY | O_CLOEXEC)));
     if (bdev_fd < 0) {
+        int saved_errno = errno;
         PLOG(ERROR) << "Failed to open block device: " << bdev_path;
         cleanup(file_path, create);
-        return nullptr;
+        return FiemapStatus::FromErrno(saved_errno);
     }
 
     uint64_t bdevsz;
     if (!GetBlockDeviceSize(bdev_fd, bdev_path, &bdevsz)) {
+        int saved_errno = errno;
         LOG(ERROR) << "Failed to get block device size for : " << bdev_path;
         cleanup(file_path, create);
-        return nullptr;
+        return FiemapStatus::FromErrno(saved_errno);
     }
 
     if (!create) {
         file_size = GetFileSize(abs_path);
         if (file_size == 0) {
             LOG(ERROR) << "Invalid file size of zero bytes for file: " << abs_path;
-            return nullptr;
+            return FiemapStatus::FromErrno(errno);
         }
     }
 
@@ -728,7 +746,7 @@
     if (!PerformFileChecks(abs_path, &blocksz, &fs_type)) {
         LOG(ERROR) << "Failed to validate file or file system for file:" << abs_path;
         cleanup(abs_path, create);
-        return nullptr;
+        return FiemapStatus::Error();
     }
 
     // Align up to the nearest block size.
@@ -737,11 +755,13 @@
     }
 
     if (create) {
-        if (!AllocateFile(file_fd, abs_path, blocksz, file_size, fs_type, std::move(progress))) {
+        auto status =
+                AllocateFile(file_fd, abs_path, blocksz, file_size, fs_type, std::move(progress));
+        if (!status.is_ok()) {
             LOG(ERROR) << "Failed to allocate file: " << abs_path << " of size: " << file_size
                        << " bytes";
             cleanup(abs_path, create);
-            return nullptr;
+            return status;
         }
     }
 
@@ -749,7 +769,7 @@
     if (!PinFile(file_fd, abs_path, fs_type)) {
         cleanup(abs_path, create);
         LOG(ERROR) << "Failed to pin the file in storage";
-        return nullptr;
+        return FiemapStatus::Error();
     }
 
     // now allocate the FiemapWriter and start setting it up
@@ -760,14 +780,14 @@
             if (!ReadFiemap(file_fd, abs_path, &fmap->extents_)) {
                 LOG(ERROR) << "Failed to read fiemap of file: " << abs_path;
                 cleanup(abs_path, create);
-                return nullptr;
+                return FiemapStatus::Error();
             }
             break;
         case MSDOS_SUPER_MAGIC:
             if (!ReadFibmap(file_fd, abs_path, &fmap->extents_)) {
                 LOG(ERROR) << "Failed to read fibmap of file: " << abs_path;
                 cleanup(abs_path, create);
-                return nullptr;
+                return FiemapStatus::Error();
             }
             break;
     }
@@ -781,7 +801,8 @@
 
     LOG(VERBOSE) << "Successfully created FiemapWriter for file " << abs_path << " on block device "
                  << bdev_path;
-    return fmap;
+    *out = std::move(fmap);
+    return FiemapStatus::Ok();
 }
 
 }  // namespace fiemap
diff --git a/fs_mgr/libfiemap/fiemap_writer_test.cpp b/fs_mgr/libfiemap/fiemap_writer_test.cpp
index 4ac7161..22a3722 100644
--- a/fs_mgr/libfiemap/fiemap_writer_test.cpp
+++ b/fs_mgr/libfiemap/fiemap_writer_test.cpp
@@ -193,7 +193,9 @@
 }
 
 TEST_F(FiemapWriterTest, MaxBlockSize) {
-    ASSERT_GT(DetermineMaximumFileSize(testfile), 0);
+    uint64_t max_piece_size = 0;
+    ASSERT_TRUE(DetermineMaximumFileSize(testfile, &max_piece_size));
+    ASSERT_GT(max_piece_size, 0);
 }
 
 TEST_F(FiemapWriterTest, FibmapBlockAddressing) {
diff --git a/fs_mgr/libfiemap/image_manager.cpp b/fs_mgr/libfiemap/image_manager.cpp
index 6a8b46e..280318e 100644
--- a/fs_mgr/libfiemap/image_manager.cpp
+++ b/fs_mgr/libfiemap/image_manager.cpp
@@ -140,27 +140,25 @@
     return access(header_file.c_str(), F_OK) == 0;
 }
 
-bool ImageManager::CreateBackingImage(const std::string& name, uint64_t size, int flags) {
-    return CreateBackingImage(name, size, flags, nullptr);
-}
-
 static bool IsUnreliablePinningAllowed(const std::string& path) {
     return android::base::StartsWith(path, "/data/gsi/dsu/") ||
            android::base::StartsWith(path, "/data/gsi/test/") ||
            android::base::StartsWith(path, "/data/gsi/ota/test/");
 }
 
-bool ImageManager::CreateBackingImage(const std::string& name, uint64_t size, int flags,
-                                      std::function<bool(uint64_t, uint64_t)>&& on_progress) {
+FiemapStatus ImageManager::CreateBackingImage(
+        const std::string& name, uint64_t size, int flags,
+        std::function<bool(uint64_t, uint64_t)>&& on_progress) {
     auto data_path = GetImageHeaderPath(name);
-    auto fw = SplitFiemap::Create(data_path, size, 0, on_progress);
-    if (!fw) {
-        return false;
+    std::unique_ptr<SplitFiemap> fw;
+    auto status = SplitFiemap::Create(data_path, size, 0, &fw, on_progress);
+    if (!status.is_ok()) {
+        return status;
     }
 
     bool reliable_pinning;
     if (!FilesystemHasReliablePinning(data_path, &reliable_pinning)) {
-        return false;
+        return FiemapStatus::Error();
     }
     if (!reliable_pinning && !IsUnreliablePinningAllowed(data_path)) {
         // For historical reasons, we allow unreliable pinning for certain use
@@ -171,7 +169,7 @@
         // proper pinning.
         LOG(ERROR) << "File system does not have reliable block pinning";
         SplitFiemap::RemoveSplitFiles(data_path);
-        return false;
+        return FiemapStatus::Error();
     }
 
     // Except for testing, we do not allow persisting metadata that references
@@ -187,24 +185,25 @@
 
         fw = {};
         SplitFiemap::RemoveSplitFiles(data_path);
-        return false;
+        return FiemapStatus::Error();
     }
 
     bool readonly = !!(flags & CREATE_IMAGE_READONLY);
     if (!UpdateMetadata(metadata_dir_, name, fw.get(), size, readonly)) {
-        return false;
+        return FiemapStatus::Error();
     }
 
     if (flags & CREATE_IMAGE_ZERO_FILL) {
-        if (!ZeroFillNewImage(name, 0)) {
+        auto res = ZeroFillNewImage(name, 0);
+        if (!res.is_ok()) {
             DeleteBackingImage(name);
-            return false;
+            return res;
         }
     }
-    return true;
+    return FiemapStatus::Ok();
 }
 
-bool ImageManager::ZeroFillNewImage(const std::string& name, uint64_t bytes) {
+FiemapStatus ImageManager::ZeroFillNewImage(const std::string& name, uint64_t bytes) {
     auto data_path = GetImageHeaderPath(name);
 
     // See the comment in MapImageDevice() about how this works.
@@ -212,13 +211,13 @@
     bool can_use_devicemapper;
     if (!FiemapWriter::GetBlockDeviceForFile(data_path, &block_device, &can_use_devicemapper)) {
         LOG(ERROR) << "Could not determine block device for " << data_path;
-        return false;
+        return FiemapStatus::Error();
     }
 
     if (!can_use_devicemapper) {
         // We've backed with loop devices, and since we store files in an
         // unencrypted folder, the initial zeroes we wrote will suffice.
-        return true;
+        return FiemapStatus::Ok();
     }
 
     // data is dm-crypt, or FBE + dm-default-key. This means the zeroes written
@@ -226,7 +225,7 @@
     // this.
     auto device = MappedDevice::Open(this, 10s, name);
     if (!device) {
-        return false;
+        return FiemapStatus::Error();
     }
 
     static constexpr size_t kChunkSize = 4096;
@@ -239,7 +238,7 @@
         remaining = get_block_device_size(device->fd());
         if (!remaining) {
             PLOG(ERROR) << "Could not get block device size for " << device->path();
-            return false;
+            return FiemapStatus::FromErrno(errno);
         }
     }
     while (remaining) {
@@ -247,11 +246,11 @@
         if (!android::base::WriteFully(device->fd(), zeroes.data(),
                                        static_cast<size_t>(to_write))) {
             PLOG(ERROR) << "write failed: " << device->path();
-            return false;
+            return FiemapStatus::FromErrno(errno);
         }
         remaining -= to_write;
     }
-    return true;
+    return FiemapStatus::Ok();
 }
 
 bool ImageManager::DeleteBackingImage(const std::string& name) {
diff --git a/fs_mgr/libfiemap/include/libfiemap/fiemap_status.h b/fs_mgr/libfiemap/include/libfiemap/fiemap_status.h
new file mode 100644
index 0000000..d7b2cf1
--- /dev/null
+++ b/fs_mgr/libfiemap/include/libfiemap/fiemap_status.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2019 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 <errno.h>
+#include <stdint.h>
+
+#include <string>
+
+namespace android::fiemap {
+
+// Represent error status of libfiemap classes.
+class FiemapStatus {
+  public:
+    enum class ErrorCode : int32_t {
+        SUCCESS = 0,
+        // Generic non-recoverable failure.
+        ERROR = INT32_MIN,
+        // Not enough space
+        NO_SPACE = -ENOSPC,
+    };
+
+    // Create from a given errno (specified in errno,h)
+    static FiemapStatus FromErrno(int error_num) { return FiemapStatus(CastErrorCode(-error_num)); }
+
+    // Create from an integer error code that is expected to be an ErrorCode
+    // value. If it isn't, Error() is returned.
+    static FiemapStatus FromErrorCode(int32_t error_code) {
+        return FiemapStatus(CastErrorCode(error_code));
+    }
+
+    // Generic error.
+    static FiemapStatus Error() { return FiemapStatus(ErrorCode::ERROR); }
+
+    // Success.
+    static FiemapStatus Ok() { return FiemapStatus(ErrorCode::SUCCESS); }
+
+    ErrorCode error_code() const { return error_code_; }
+    bool is_ok() const { return error_code() == ErrorCode::SUCCESS; }
+    operator bool() const { return is_ok(); }
+
+    // For logging and debugging only.
+    std::string string() const;
+
+  protected:
+    FiemapStatus(ErrorCode code) : error_code_(code) {}
+
+  private:
+    ErrorCode error_code_;
+
+    static ErrorCode CastErrorCode(int error);
+};
+
+}  // namespace android::fiemap
diff --git a/fs_mgr/libfiemap/include/libfiemap/fiemap_writer.h b/fs_mgr/libfiemap/include/libfiemap/fiemap_writer.h
index c692265..dd345f6 100644
--- a/fs_mgr/libfiemap/include/libfiemap/fiemap_writer.h
+++ b/fs_mgr/libfiemap/include/libfiemap/fiemap_writer.h
@@ -27,6 +27,8 @@
 
 #include <android-base/unique_fd.h>
 
+#include <libfiemap/fiemap_status.h>
+
 namespace android {
 namespace fiemap {
 
@@ -47,6 +49,9 @@
     static FiemapUniquePtr Open(const std::string& file_path, uint64_t file_size,
                                 bool create = true,
                                 std::function<bool(uint64_t, uint64_t)> progress = {});
+    static FiemapStatus Open(const std::string& file_path, uint64_t file_size, FiemapUniquePtr* out,
+                             bool create = true,
+                             std::function<bool(uint64_t, uint64_t)> progress = {});
 
     // Check that a file still has the same extents since it was last opened with FiemapWriter,
     // assuming the file was not resized outside of FiemapWriter. Returns false either on error
diff --git a/fs_mgr/libfiemap/include/libfiemap/image_manager.h b/fs_mgr/libfiemap/include/libfiemap/image_manager.h
index 7b907c0..2c13229 100644
--- a/fs_mgr/libfiemap/include/libfiemap/image_manager.h
+++ b/fs_mgr/libfiemap/include/libfiemap/image_manager.h
@@ -25,6 +25,7 @@
 #include <string>
 
 #include <android-base/unique_fd.h>
+#include <libfiemap/fiemap_status.h>
 #include <liblp/partition_opener.h>
 
 namespace android {
@@ -52,7 +53,9 @@
     // of the image is undefined. If zero-fill is requested, and the operation
     // cannot be completed, the image will be deleted and this function will
     // return false.
-    virtual bool CreateBackingImage(const std::string& name, uint64_t size, int flags) = 0;
+    virtual FiemapStatus CreateBackingImage(
+            const std::string& name, uint64_t size, int flags,
+            std::function<bool(uint64_t, uint64_t)>&& on_progress = nullptr) = 0;
 
     // Delete an image created with CreateBackingImage. Its entry will be
     // removed from the associated lp_metadata file.
@@ -113,7 +116,7 @@
 
     // Writes |bytes| zeros to |name| file. If |bytes| is 0, then the
     // whole file if filled with zeros.
-    virtual bool ZeroFillNewImage(const std::string& name, uint64_t bytes) = 0;
+    virtual FiemapStatus ZeroFillNewImage(const std::string& name, uint64_t bytes) = 0;
 
     // Find and remove all images and metadata for this manager.
     virtual bool RemoveAllImages() = 0;
@@ -133,7 +136,8 @@
     static std::unique_ptr<ImageManager> Open(const std::string& dir_prefix);
 
     // Methods that must be implemented from IImageManager.
-    bool CreateBackingImage(const std::string& name, uint64_t size, int flags) override;
+    FiemapStatus CreateBackingImage(const std::string& name, uint64_t size, int flags,
+                                    std::function<bool(uint64_t, uint64_t)>&& on_progress) override;
     bool DeleteBackingImage(const std::string& name) override;
     bool MapImageDevice(const std::string& name, const std::chrono::milliseconds& timeout_ms,
                         std::string* path) override;
@@ -149,9 +153,6 @@
     bool MapAllImages(const std::function<bool(std::set<std::string>)>& init) override;
 
     std::vector<std::string> GetAllBackingImages();
-    // Same as CreateBackingImage, but provides a progress notification.
-    bool CreateBackingImage(const std::string& name, uint64_t size, int flags,
-                            std::function<bool(uint64_t, uint64_t)>&& on_progress);
 
     // Returns true if the named partition exists. This does not check the
     // consistency of the backing image/data file.
@@ -164,7 +165,7 @@
     void set_partition_opener(std::unique_ptr<IPartitionOpener>&& opener);
 
     // Writes |bytes| zeros at the beginning of the passed image
-    bool ZeroFillNewImage(const std::string& name, uint64_t bytes);
+    FiemapStatus ZeroFillNewImage(const std::string& name, uint64_t bytes);
 
   private:
     ImageManager(const std::string& metadata_dir, const std::string& data_dir);
diff --git a/fs_mgr/libfiemap/include/libfiemap/split_fiemap_writer.h b/fs_mgr/libfiemap/include/libfiemap/split_fiemap_writer.h
index feffb3d..d739fcf 100644
--- a/fs_mgr/libfiemap/include/libfiemap/split_fiemap_writer.h
+++ b/fs_mgr/libfiemap/include/libfiemap/split_fiemap_writer.h
@@ -25,7 +25,8 @@
 
 #include <android-base/unique_fd.h>
 
-#include "fiemap_writer.h"
+#include <libfiemap/fiemap_status.h>
+#include <libfiemap/fiemap_writer.h>
 
 namespace android {
 namespace fiemap {
@@ -43,6 +44,9 @@
     static std::unique_ptr<SplitFiemap> Create(const std::string& file_path, uint64_t file_size,
                                                uint64_t max_piece_size,
                                                ProgressCallback progress = {});
+    static FiemapStatus Create(const std::string& file_path, uint64_t file_size,
+                               uint64_t max_piece_size, std::unique_ptr<SplitFiemap>* out_val,
+                               ProgressCallback progress = {});
 
     // Open an existing split fiemap file.
     static std::unique_ptr<SplitFiemap> Open(const std::string& file_path);
diff --git a/fs_mgr/libfiemap/split_fiemap_writer.cpp b/fs_mgr/libfiemap/split_fiemap_writer.cpp
index cc54f20..12c7397 100644
--- a/fs_mgr/libfiemap/split_fiemap_writer.cpp
+++ b/fs_mgr/libfiemap/split_fiemap_writer.cpp
@@ -45,16 +45,28 @@
 std::unique_ptr<SplitFiemap> SplitFiemap::Create(const std::string& file_path, uint64_t file_size,
                                                  uint64_t max_piece_size,
                                                  ProgressCallback progress) {
+    std::unique_ptr<SplitFiemap> ret;
+    if (!Create(file_path, file_size, max_piece_size, &ret, progress).is_ok()) {
+        return nullptr;
+    }
+    return ret;
+}
+
+FiemapStatus SplitFiemap::Create(const std::string& file_path, uint64_t file_size,
+                                 uint64_t max_piece_size, std::unique_ptr<SplitFiemap>* out_val,
+                                 ProgressCallback progress) {
+    out_val->reset();
+
     if (!file_size) {
         LOG(ERROR) << "Cannot create a fiemap for a 0-length file: " << file_path;
-        return nullptr;
+        return FiemapStatus::Error();
     }
 
     if (!max_piece_size) {
-        max_piece_size = DetermineMaximumFileSize(file_path);
-        if (!max_piece_size) {
+        auto status = DetermineMaximumFileSize(file_path, &max_piece_size);
+        if (!status.is_ok()) {
             LOG(ERROR) << "Could not determine maximum file size for " << file_path;
-            return nullptr;
+            return status;
         }
     }
 
@@ -75,7 +87,6 @@
         }
         return true;
     };
-
     std::unique_ptr<SplitFiemap> out(new SplitFiemap());
     out->creating_ = true;
     out->list_file_ = file_path;
@@ -85,14 +96,17 @@
     while (remaining_bytes) {
         if (out->files_.size() >= kMaxFilePieces) {
             LOG(ERROR) << "Requested size " << file_size << " created too many split files";
-            return nullptr;
+            out.reset();
+            return FiemapStatus::Error();
         }
         std::string chunk_path =
                 android::base::StringPrintf("%s.%04d", file_path.c_str(), (int)out->files_.size());
         uint64_t chunk_size = std::min(max_piece_size, remaining_bytes);
-        auto writer = FiemapWriter::Open(chunk_path, chunk_size, true, on_progress);
-        if (!writer) {
-            return nullptr;
+        FiemapUniquePtr writer;
+        auto status = FiemapWriter::Open(chunk_path, chunk_size, &writer, true, on_progress);
+        if (!status.is_ok()) {
+            out.reset();
+            return status;
         }
 
         // To make sure the alignment doesn't create too much inconsistency, we
@@ -110,20 +124,23 @@
     unique_fd fd(open(out->list_file_.c_str(), O_CREAT | O_WRONLY | O_CLOEXEC, 0660));
     if (fd < 0) {
         PLOG(ERROR) << "Failed to open " << file_path;
-        return nullptr;
+        out.reset();
+        return FiemapStatus::FromErrno(errno);
     }
 
     for (const auto& writer : out->files_) {
         std::string line = android::base::Basename(writer->file_path()) + "\n";
         if (!android::base::WriteFully(fd, line.data(), line.size())) {
             PLOG(ERROR) << "Write failed " << file_path;
-            return nullptr;
+            out.reset();
+            return FiemapStatus::FromErrno(errno);
         }
     }
 
     // Unset this bit, so we don't unlink on destruction.
     out->creating_ = false;
-    return out;
+    *out_val = std::move(out);
+    return FiemapStatus::Ok();
 }
 
 std::unique_ptr<SplitFiemap> SplitFiemap::Open(const std::string& file_path) {
diff --git a/fs_mgr/libfiemap/utility.cpp b/fs_mgr/libfiemap/utility.cpp
index 955e544..bbb0510 100644
--- a/fs_mgr/libfiemap/utility.cpp
+++ b/fs_mgr/libfiemap/utility.cpp
@@ -37,29 +37,30 @@
 
 static constexpr char kUserdataDevice[] = "/dev/block/by-name/userdata";
 
-uint64_t DetermineMaximumFileSize(const std::string& file_path) {
+FiemapStatus DetermineMaximumFileSize(const std::string& file_path, uint64_t* result) {
     // Create the smallest file possible (one block).
-    auto writer = FiemapWriter::Open(file_path, 1);
-    if (!writer) {
-        return 0;
+    FiemapUniquePtr writer;
+    auto status = FiemapWriter::Open(file_path, 1, &writer);
+    if (!status.is_ok()) {
+        return status;
     }
 
-    uint64_t result = 0;
+    *result = 0;
     switch (writer->fs_type()) {
         case EXT4_SUPER_MAGIC:
             // The minimum is 16GiB, so just report that. If we wanted we could parse the
             // superblock and figure out if 64-bit support is enabled.
-            result = 17179869184ULL;
+            *result = 17179869184ULL;
             break;
         case F2FS_SUPER_MAGIC:
             // Formula is from https://www.kernel.org/doc/Documentation/filesystems/f2fs.txt
             // 4KB * (923 + 2 * 1018 + 2 * 1018 * 1018 + 1018 * 1018 * 1018) := 3.94TB.
-            result = 4329690886144ULL;
+            *result = 4329690886144ULL;
             break;
         case MSDOS_SUPER_MAGIC:
             // 4GB-1, which we want aligned to the block size.
-            result = 4294967295;
-            result -= (result % writer->block_size());
+            *result = 4294967295;
+            *result -= (*result % writer->block_size());
             break;
         default:
             LOG(ERROR) << "Unknown file system type: " << writer->fs_type();
@@ -70,7 +71,7 @@
     writer = nullptr;
     unlink(file_path.c_str());
 
-    return result;
+    return FiemapStatus::Ok();
 }
 
 // Given a SplitFiemap, this returns a device path that will work during first-
diff --git a/fs_mgr/libfiemap/utility.h b/fs_mgr/libfiemap/utility.h
index 24ebc57..4c0bc2b 100644
--- a/fs_mgr/libfiemap/utility.h
+++ b/fs_mgr/libfiemap/utility.h
@@ -28,7 +28,7 @@
 // Given a file that will be created, determine the maximum size its containing
 // filesystem allows. Note this is a theoretical maximum size; free space is
 // ignored entirely.
-uint64_t DetermineMaximumFileSize(const std::string& file_path);
+FiemapStatus DetermineMaximumFileSize(const std::string& file_path, uint64_t* result);
 
 // Given a SplitFiemap, this returns a device path that will work during first-
 // stage init (i.e., its path can be found by InitRequiredDevices).
diff --git a/fs_mgr/libsnapshot/Android.bp b/fs_mgr/libsnapshot/Android.bp
index eadcecc..9e67c66 100644
--- a/fs_mgr/libsnapshot/Android.bp
+++ b/fs_mgr/libsnapshot/Android.bp
@@ -127,6 +127,7 @@
         "include_test",
     ],
     srcs: [
+        "android/snapshot/snapshot.proto",
         "test_helpers.cpp",
     ],
     shared_libs: [
diff --git a/fs_mgr/libsnapshot/OWNERS b/fs_mgr/libsnapshot/OWNERS
index 0cfa7e4..801c446 100644
--- a/fs_mgr/libsnapshot/OWNERS
+++ b/fs_mgr/libsnapshot/OWNERS
@@ -1,2 +1,3 @@
+balsini@google.com
 dvander@google.com
 elsk@google.com
diff --git a/fs_mgr/libsnapshot/android/snapshot/snapshot.proto b/fs_mgr/libsnapshot/android/snapshot/snapshot.proto
index 629c3a4..a3a518d 100644
--- a/fs_mgr/libsnapshot/android/snapshot/snapshot.proto
+++ b/fs_mgr/libsnapshot/android/snapshot/snapshot.proto
@@ -85,3 +85,49 @@
     // This is non-zero when |state| == MERGING or MERGE_COMPLETED.
     uint64 metadata_sectors = 8;
 }
+
+// Next: 8
+enum UpdateState {
+    // No update or merge is in progress.
+    None = 0;
+
+    // An update is applying; snapshots may already exist.
+    Initiated = 1;
+
+    // An update is pending, but has not been successfully booted yet.
+    Unverified = 2;
+
+    // The kernel is merging in the background.
+    Merging = 3;
+
+    // Post-merge cleanup steps could not be completed due to a transient
+    // error, but the next reboot will finish any pending operations.
+    MergeNeedsReboot = 4;
+
+    // Merging is complete, and needs to be acknowledged.
+    MergeCompleted = 5;
+
+    // Merging failed due to an unrecoverable error.
+    MergeFailed = 6;
+
+    // The update was implicitly cancelled, either by a rollback or a flash
+    // operation via fastboot. This state can only be returned by WaitForMerge.
+    Cancelled = 7;
+};
+
+// Next: 5
+message SnapshotUpdateStatus {
+    UpdateState state = 1;
+
+    // Total number of sectors allocated in the COW files before performing the
+    // merge operation.  This field is used to keep track of the total number
+    // of sectors modified to monitor and show the progress of the merge during
+    // an update.
+    uint64 sectors_allocated = 2;
+
+    // Total number of sectors of all the snapshot devices.
+    uint64 total_sectors = 3;
+
+    // Sectors allocated for metadata in all the snapshot devices.
+    uint64 metadata_sectors = 4;
+}
diff --git a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
index 445e6db..61946f7 100644
--- a/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
+++ b/fs_mgr/libsnapshot/include/libsnapshot/snapshot.h
@@ -26,6 +26,7 @@
 #include <vector>
 
 #include <android-base/unique_fd.h>
+#include <android/snapshot/snapshot.pb.h>
 #include <fs_mgr_dm_linear.h>
 #include <libdm/dm.h>
 #include <libfiemap/image_manager.h>
@@ -74,34 +75,11 @@
 
 bool SourceCopyOperationIsClone(const chromeos_update_engine::InstallOperation& operation);
 
-enum class UpdateState : unsigned int {
-    // No update or merge is in progress.
-    None,
-
-    // An update is applying; snapshots may already exist.
-    Initiated,
-
-    // An update is pending, but has not been successfully booted yet.
-    Unverified,
-
-    // The kernel is merging in the background.
-    Merging,
-
-    // Post-merge cleanup steps could not be completed due to a transient
-    // error, but the next reboot will finish any pending operations.
-    MergeNeedsReboot,
-
-    // Merging is complete, and needs to be acknowledged.
-    MergeCompleted,
-
-    // Merging failed due to an unrecoverable error.
-    MergeFailed,
-
-    // The update was implicitly cancelled, either by a rollback or a flash
-    // operation via fastboot. This state can only be returned by WaitForMerge.
-    Cancelled
+enum class CreateResult : unsigned int {
+    ERROR,
+    CREATED,
+    NOT_CREATED,
 };
-std::ostream& operator<<(std::ostream& os, UpdateState state);
 
 class SnapshotManager final {
     using CreateLogicalPartitionParams = android::fs_mgr::CreateLogicalPartitionParams;
@@ -110,8 +88,30 @@
     using MetadataBuilder = android::fs_mgr::MetadataBuilder;
     using DeltaArchiveManifest = chromeos_update_engine::DeltaArchiveManifest;
     using MergeStatus = android::hardware::boot::V1_1::MergeStatus;
+    using FiemapStatus = android::fiemap::FiemapStatus;
 
   public:
+    // SnapshotManager functions return either bool or Return objects. "Return" types provides
+    // more information about the reason of the failure.
+    class Return : public FiemapStatus {
+      public:
+        // Total required size on /userdata.
+        uint64_t required_size() const { return required_size_; }
+
+        static Return Ok() { return Return(FiemapStatus::ErrorCode::SUCCESS); }
+        static Return Error() { return Return(FiemapStatus::ErrorCode::ERROR); }
+        static Return NoSpace(uint64_t size) {
+            return Return(FiemapStatus::ErrorCode::NO_SPACE, size);
+        }
+        // Does not set required_size_ properly even when status.error_code() == NO_SPACE.
+        explicit Return(const FiemapStatus& status) : Return(status.error_code()) {}
+
+      private:
+        uint64_t required_size_;
+        Return(FiemapStatus::ErrorCode code, uint64_t required_size = 0)
+            : FiemapStatus(code), required_size_(required_size) {}
+    };
+
     // Dependency injection for testing.
     class IDeviceInfo {
       public:
@@ -216,7 +216,7 @@
     // Create necessary COW device / files for OTA clients. New logical partitions will be added to
     // group "cow" in target_metadata. Regions of partitions of current_metadata will be
     // "write-protected" and snapshotted.
-    bool CreateUpdateSnapshots(const DeltaArchiveManifest& manifest);
+    Return CreateUpdateSnapshots(const DeltaArchiveManifest& manifest);
 
     // Map a snapshotted partition for OTA clients to write to. Write-protected regions are
     // determined previously in CreateSnapshots.
@@ -246,6 +246,17 @@
     // optional callback fires periodically to query progress via GetUpdateState.
     bool HandleImminentDataWipe(const std::function<void()>& callback = {});
 
+    // This method is only allowed in recovery and is used as a helper to
+    // initialize the snapshot devices as a requirement to mount a snapshotted
+    // /system in recovery.
+    // This function returns:
+    // - CreateResult::CREATED if snapshot devices were successfully created;
+    // - CreateResult::NOT_CREATED if it was not necessary to create snapshot
+    // devices;
+    // - CreateResult::ERROR if a fatal error occurred, mounting /system should
+    // be aborted.
+    CreateResult RecoveryCreateSnapshotDevices();
+
     // Dump debug information.
     bool Dump(std::ostream& os);
 
@@ -342,7 +353,7 @@
 
     // |name| should be the base partition name (e.g. "system_a"). Create the
     // backing COW image using the size previously passed to CreateSnapshot().
-    bool CreateCowImage(LockedFile* lock, const std::string& name);
+    Return CreateCowImage(LockedFile* lock, const std::string& name);
 
     // Map a snapshot device that was previously created with CreateSnapshot.
     // If a merge was previously initiated, the device-mapper table will have a
@@ -394,7 +405,9 @@
 
     // Interact with /metadata/ota/state.
     UpdateState ReadUpdateState(LockedFile* file);
+    SnapshotUpdateStatus ReadSnapshotUpdateStatus(LockedFile* file);
     bool WriteUpdateState(LockedFile* file, UpdateState state);
+    bool WriteSnapshotUpdateStatus(LockedFile* file, const SnapshotUpdateStatus& status);
     std::string GetStateFilePath() const;
 
     // Helpers for merging.
@@ -482,14 +495,14 @@
 
     // Helper for CreateUpdateSnapshots.
     // Creates all underlying images, COW partitions and snapshot files. Does not initialize them.
-    bool CreateUpdateSnapshotsInternal(LockedFile* lock, const DeltaArchiveManifest& manifest,
-                                       PartitionCowCreator* cow_creator,
-                                       AutoDeviceList* created_devices,
-                                       std::map<std::string, SnapshotStatus>* all_snapshot_status);
+    Return CreateUpdateSnapshotsInternal(
+            LockedFile* lock, const DeltaArchiveManifest& manifest,
+            PartitionCowCreator* cow_creator, AutoDeviceList* created_devices,
+            std::map<std::string, SnapshotStatus>* all_snapshot_status);
 
     // Initialize snapshots so that they can be mapped later.
     // Map the COW partition and zero-initialize the header.
-    bool InitializeUpdateSnapshots(
+    Return InitializeUpdateSnapshots(
             LockedFile* lock, MetadataBuilder* target_metadata,
             const LpMetadata* exported_target_metadata, const std::string& target_suffix,
             const std::map<std::string, SnapshotStatus>& all_snapshot_status);
diff --git a/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h b/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
index 2bf1b57..11de6ed 100644
--- a/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
+++ b/fs_mgr/libsnapshot/include_test/libsnapshot/test_helpers.h
@@ -14,10 +14,12 @@
 
 #pragma once
 
+#include <memory>
 #include <optional>
 #include <string>
 #include <unordered_set>
 
+#include <android-base/file.h>
 #include <android/hardware/boot/1.1/IBootControl.h>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ -155,5 +157,28 @@
 // Get partition size from update package metadata.
 uint64_t GetSize(PartitionUpdate* partition_update);
 
+// Util class for test cases on low space scenario. These tests assumes image manager
+// uses /data as backup device.
+class LowSpaceUserdata {
+  public:
+    // Set the maximum free space allowed for this test. If /userdata has more space than the given
+    // number, a file is allocated to consume space.
+    AssertionResult Init(uint64_t max_free_space);
+
+    uint64_t free_space() const;
+    uint64_t available_space() const;
+    uint64_t bsize() const;
+
+  private:
+    AssertionResult ReadUserdataStats();
+
+    static constexpr const char* kUserDataDevice = "/data";
+    std::unique_ptr<TemporaryFile> big_file_;
+    bool initialized_ = false;
+    uint64_t free_space_ = 0;
+    uint64_t available_space_ = 0;
+    uint64_t bsize_ = 0;
+};
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot.cpp b/fs_mgr/libsnapshot/snapshot.cpp
index a0ec068..70a69a5 100644
--- a/fs_mgr/libsnapshot/snapshot.cpp
+++ b/fs_mgr/libsnapshot/snapshot.cpp
@@ -54,6 +54,7 @@
 using android::dm::DmTargetSnapshot;
 using android::dm::kSectorSize;
 using android::dm::SnapshotStorageMode;
+using android::fiemap::FiemapStatus;
 using android::fiemap::IImageManager;
 using android::fs_mgr::CreateDmTable;
 using android::fs_mgr::CreateLogicalPartition;
@@ -289,14 +290,14 @@
     return true;
 }
 
-bool SnapshotManager::CreateCowImage(LockedFile* lock, const std::string& name) {
+SnapshotManager::Return SnapshotManager::CreateCowImage(LockedFile* lock, const std::string& name) {
     CHECK(lock);
     CHECK(lock->lock_mode() == LOCK_EX);
-    if (!EnsureImageManager()) return false;
+    if (!EnsureImageManager()) return Return::Error();
 
     SnapshotStatus status;
     if (!ReadSnapshotStatus(lock, name, &status)) {
-        return false;
+        return Return::Error();
     }
 
     // The COW file size should have been rounded up to the nearest sector in CreateSnapshot.
@@ -304,12 +305,12 @@
     if (status.cow_file_size() % kSectorSize != 0) {
         LOG(ERROR) << "Snapshot " << name << " COW file size is not a multiple of the sector size: "
                    << status.cow_file_size();
-        return false;
+        return Return::Error();
     }
 
     std::string cow_image_name = GetCowImageDeviceName(name);
     int cow_flags = IImageManager::CREATE_IMAGE_DEFAULT;
-    return images_->CreateBackingImage(cow_image_name, status.cow_file_size(), cow_flags);
+    return Return(images_->CreateBackingImage(cow_image_name, status.cow_file_size(), cow_flags));
 }
 
 bool SnapshotManager::MapSnapshot(LockedFile* lock, const std::string& name,
@@ -559,9 +560,26 @@
         }
     }
 
+    DmTargetSnapshot::Status initial_target_values = {};
+    for (const auto& snapshot : snapshots) {
+        DmTargetSnapshot::Status current_status;
+        if (!QuerySnapshotStatus(snapshot, nullptr, &current_status)) {
+            return false;
+        }
+        initial_target_values.sectors_allocated += current_status.sectors_allocated;
+        initial_target_values.total_sectors += current_status.total_sectors;
+        initial_target_values.metadata_sectors += current_status.metadata_sectors;
+    }
+
+    SnapshotUpdateStatus initial_status;
+    initial_status.set_state(UpdateState::Merging);
+    initial_status.set_sectors_allocated(initial_target_values.sectors_allocated);
+    initial_status.set_total_sectors(initial_target_values.total_sectors);
+    initial_status.set_metadata_sectors(initial_target_values.metadata_sectors);
+
     // Point of no return - mark that we're starting a merge. From now on every
     // snapshot must be a merge target.
-    if (!WriteUpdateState(lock.get(), UpdateState::Merging)) {
+    if (!WriteSnapshotUpdateStatus(lock.get(), initial_status)) {
         return false;
     }
 
@@ -1642,15 +1660,7 @@
     return OpenLock(LOCK_EX);
 }
 
-UpdateState SnapshotManager::ReadUpdateState(LockedFile* lock) {
-    CHECK(lock);
-
-    std::string contents;
-    if (!android::base::ReadFileToString(GetStateFilePath(), &contents)) {
-        PLOG(ERROR) << "Read state file failed";
-        return UpdateState::None;
-    }
-
+static UpdateState UpdateStateFromString(const std::string& contents) {
     if (contents.empty() || contents == "none") {
         return UpdateState::None;
     } else if (contents == "initiated") {
@@ -1693,18 +1703,54 @@
     }
 }
 
+UpdateState SnapshotManager::ReadUpdateState(LockedFile* lock) {
+    SnapshotUpdateStatus status = ReadSnapshotUpdateStatus(lock);
+    return status.state();
+}
+
+SnapshotUpdateStatus SnapshotManager::ReadSnapshotUpdateStatus(LockedFile* lock) {
+    CHECK(lock);
+
+    SnapshotUpdateStatus status = {};
+    std::string contents;
+    if (!android::base::ReadFileToString(GetStateFilePath(), &contents)) {
+        PLOG(ERROR) << "Read state file failed";
+        status.set_state(UpdateState::None);
+        return status;
+    }
+
+    if (!status.ParseFromString(contents)) {
+        LOG(WARNING) << "Unable to parse state file as SnapshotUpdateStatus, using the old format";
+
+        // Try to rollback to legacy file to support devices that are
+        // currently using the old file format.
+        // TODO(b/147409432)
+        status.set_state(UpdateStateFromString(contents));
+    }
+
+    return status;
+}
+
 bool SnapshotManager::WriteUpdateState(LockedFile* lock, UpdateState state) {
+    SnapshotUpdateStatus status = {};
+    status.set_state(state);
+    return WriteSnapshotUpdateStatus(lock, status);
+}
+
+bool SnapshotManager::WriteSnapshotUpdateStatus(LockedFile* lock,
+                                                const SnapshotUpdateStatus& status) {
     CHECK(lock);
     CHECK(lock->lock_mode() == LOCK_EX);
 
-    std::stringstream ss;
-    ss << state;
-    std::string contents = ss.str();
-    if (contents.empty()) return false;
+    std::string contents;
+    if (!status.SerializeToString(&contents)) {
+        LOG(ERROR) << "Unable to serialize SnapshotUpdateStatus.";
+        return false;
+    }
 
 #ifdef LIBSNAPSHOT_USE_HAL
     auto merge_status = MergeStatus::UNKNOWN;
-    switch (state) {
+    switch (status.state()) {
         // The needs-reboot and completed cases imply that /data and /metadata
         // can be safely wiped, so we don't report a merge status.
         case UpdateState::None:
@@ -1723,7 +1769,7 @@
         default:
             // Note that Cancelled flows to here - it is never written, since
             // it only communicates a transient state to the caller.
-            LOG(ERROR) << "Unexpected update status: " << state;
+            LOG(ERROR) << "Unexpected update status: " << status.state();
             break;
     }
 
@@ -1844,9 +1890,23 @@
     }
 }
 
-bool SnapshotManager::CreateUpdateSnapshots(const DeltaArchiveManifest& manifest) {
+static SnapshotManager::Return AddRequiredSpace(
+        SnapshotManager::Return orig,
+        const std::map<std::string, SnapshotStatus>& all_snapshot_status) {
+    if (orig.error_code() != SnapshotManager::Return::ErrorCode::NO_SPACE) {
+        return orig;
+    }
+    uint64_t sum = 0;
+    for (auto&& [name, status] : all_snapshot_status) {
+        sum += status.cow_file_size();
+    }
+    return SnapshotManager::Return::NoSpace(sum);
+}
+
+SnapshotManager::Return SnapshotManager::CreateUpdateSnapshots(
+        const DeltaArchiveManifest& manifest) {
     auto lock = LockExclusive();
-    if (!lock) return false;
+    if (!lock) return Return::Error();
 
     // TODO(b/134949511): remove this check. Right now, with overlayfs mounted, the scratch
     // partition takes up a big chunk of space in super, causing COW images to be created on
@@ -1854,7 +1914,7 @@
     if (device_->IsOverlayfsSetup()) {
         LOG(ERROR) << "Cannot create update snapshots with overlayfs setup. Run `adb enable-verity`"
                    << ", reboot, then try again.";
-        return false;
+        return Return::Error();
     }
 
     const auto& opener = device_->GetPartitionOpener();
@@ -1879,7 +1939,7 @@
     SnapshotMetadataUpdater metadata_updater(target_metadata.get(), target_slot, manifest);
     if (!metadata_updater.Update()) {
         LOG(ERROR) << "Cannot calculate new metadata.";
-        return false;
+        return Return::Error();
     }
 
     // Delete previous COW partitions in current_metadata so that PartitionCowCreator marks those as
@@ -1911,36 +1971,34 @@
             .extra_extents = {},
     };
 
-    if (!CreateUpdateSnapshotsInternal(lock.get(), manifest, &cow_creator, &created_devices,
-                                       &all_snapshot_status)) {
-        return false;
-    }
+    auto ret = CreateUpdateSnapshotsInternal(lock.get(), manifest, &cow_creator, &created_devices,
+                                             &all_snapshot_status);
+    if (!ret.is_ok()) return ret;
 
     auto exported_target_metadata = target_metadata->Export();
     if (exported_target_metadata == nullptr) {
         LOG(ERROR) << "Cannot export target metadata";
-        return false;
+        return Return::Error();
     }
 
-    if (!InitializeUpdateSnapshots(lock.get(), target_metadata.get(),
-                                   exported_target_metadata.get(), target_suffix,
-                                   all_snapshot_status)) {
-        return false;
-    }
+    ret = InitializeUpdateSnapshots(lock.get(), target_metadata.get(),
+                                    exported_target_metadata.get(), target_suffix,
+                                    all_snapshot_status);
+    if (!ret.is_ok()) return ret;
 
     if (!UpdatePartitionTable(opener, device_->GetSuperDevice(target_slot),
                               *exported_target_metadata, target_slot)) {
         LOG(ERROR) << "Cannot write target metadata";
-        return false;
+        return Return::Error();
     }
 
     created_devices.Release();
     LOG(INFO) << "Successfully created all snapshots for target slot " << target_suffix;
 
-    return true;
+    return Return::Ok();
 }
 
-bool SnapshotManager::CreateUpdateSnapshotsInternal(
+SnapshotManager::Return SnapshotManager::CreateUpdateSnapshotsInternal(
         LockedFile* lock, const DeltaArchiveManifest& manifest, PartitionCowCreator* cow_creator,
         AutoDeviceList* created_devices,
         std::map<std::string, SnapshotStatus>* all_snapshot_status) {
@@ -1951,7 +2009,7 @@
 
     if (!target_metadata->AddGroup(kCowGroupName, 0)) {
         LOG(ERROR) << "Cannot add group " << kCowGroupName;
-        return false;
+        return Return::Error();
     }
 
     std::map<std::string, const RepeatedPtrField<InstallOperation>*> install_operation_map;
@@ -1963,7 +2021,7 @@
         if (!inserted) {
             LOG(ERROR) << "Duplicated partition " << partition_update.partition_name()
                        << " in update manifest.";
-            return false;
+            return Return::Error();
         }
 
         auto& extra_extents = extra_extents_map[suffixed_name];
@@ -1992,7 +2050,7 @@
         // Compute the device sizes for the partition.
         auto cow_creator_ret = cow_creator->Run();
         if (!cow_creator_ret.has_value()) {
-            return false;
+            return Return::Error();
         }
 
         LOG(INFO) << "For partition " << target_partition->name()
@@ -2006,7 +2064,7 @@
         if (!DeleteSnapshot(lock, target_partition->name())) {
             LOG(ERROR) << "Cannot delete existing snapshot before creating a new one for partition "
                        << target_partition->name();
-            return false;
+            return Return::Error();
         }
 
         // It is possible that the whole partition uses free space in super, and snapshot / COW
@@ -2024,7 +2082,7 @@
 
         // Store these device sizes to snapshot status file.
         if (!CreateSnapshot(lock, &cow_creator_ret->snapshot_status)) {
-            return false;
+            return Return::Error();
         }
         created_devices->EmplaceBack<AutoDeleteSnapshot>(this, lock, target_partition->name());
 
@@ -2038,7 +2096,7 @@
             auto cow_partition = target_metadata->AddPartition(GetCowName(target_partition->name()),
                                                                kCowGroupName, 0 /* flags */);
             if (cow_partition == nullptr) {
-                return false;
+                return Return::Error();
             }
 
             if (!target_metadata->ResizePartition(
@@ -2046,28 +2104,34 @@
                         cow_creator_ret->cow_partition_usable_regions)) {
                 LOG(ERROR) << "Cannot create COW partition on metadata with size "
                            << cow_creator_ret->snapshot_status.cow_partition_size();
-                return false;
+                return Return::Error();
             }
             // Only the in-memory target_metadata is modified; nothing to clean up if there is an
             // error in the future.
         }
 
-        // Create the backing COW image if necessary.
-        if (cow_creator_ret->snapshot_status.cow_file_size() > 0) {
-            if (!CreateCowImage(lock, target_partition->name())) {
-                return false;
-            }
-        }
-
         all_snapshot_status->emplace(target_partition->name(),
                                      std::move(cow_creator_ret->snapshot_status));
 
-        LOG(INFO) << "Successfully created snapshot for " << target_partition->name();
+        LOG(INFO) << "Successfully created snapshot partition for " << target_partition->name();
     }
-    return true;
+
+    LOG(INFO) << "Allocating CoW images.";
+
+    for (auto&& [name, snapshot_status] : *all_snapshot_status) {
+        // Create the backing COW image if necessary.
+        if (snapshot_status.cow_file_size() > 0) {
+            auto ret = CreateCowImage(lock, name);
+            if (!ret.is_ok()) return AddRequiredSpace(ret, *all_snapshot_status);
+        }
+
+        LOG(INFO) << "Successfully created snapshot for " << name;
+    }
+
+    return Return::Ok();
 }
 
-bool SnapshotManager::InitializeUpdateSnapshots(
+SnapshotManager::Return SnapshotManager::InitializeUpdateSnapshots(
         LockedFile* lock, MetadataBuilder* target_metadata,
         const LpMetadata* exported_target_metadata, const std::string& target_suffix,
         const std::map<std::string, SnapshotStatus>& all_snapshot_status) {
@@ -2086,7 +2150,7 @@
         if (!UnmapPartitionWithSnapshot(lock, target_partition->name())) {
             LOG(ERROR) << "Cannot unmap existing COW devices before re-mapping them for zero-fill: "
                        << target_partition->name();
-            return false;
+            return Return::Error();
         }
 
         auto it = all_snapshot_status.find(target_partition->name());
@@ -2094,23 +2158,24 @@
         cow_params.partition_name = target_partition->name();
         std::string cow_name;
         if (!MapCowDevices(lock, cow_params, it->second, &created_devices_for_cow, &cow_name)) {
-            return false;
+            return Return::Error();
         }
 
         std::string cow_path;
         if (!dm.GetDmDevicePathByName(cow_name, &cow_path)) {
             LOG(ERROR) << "Cannot determine path for " << cow_name;
-            return false;
+            return Return::Error();
         }
 
-        if (!InitializeCow(cow_path)) {
+        auto ret = InitializeCow(cow_path);
+        if (!ret.is_ok()) {
             LOG(ERROR) << "Can't zero-fill COW device for " << target_partition->name() << ": "
                        << cow_path;
-            return false;
+            return AddRequiredSpace(ret, all_snapshot_status);
         }
         // Let destructor of created_devices_for_cow to unmap the COW devices.
     };
-    return true;
+    return Return::Ok();
 }
 
 bool SnapshotManager::MapUpdateSnapshot(const CreateLogicalPartitionParams& params,
@@ -2356,5 +2421,37 @@
     return true;
 }
 
+CreateResult SnapshotManager::RecoveryCreateSnapshotDevices() {
+    if (!device_->IsRecovery()) {
+        LOG(ERROR) << __func__ << " is only allowed in recovery.";
+        return CreateResult::NOT_CREATED;
+    }
+
+    auto mount = EnsureMetadataMounted();
+    if (!mount || !mount->HasDevice()) {
+        LOG(ERROR) << "Couldn't mount Metadata.";
+        return CreateResult::NOT_CREATED;
+    }
+
+    auto state_file = GetStateFilePath();
+    if (access(state_file.c_str(), F_OK) != 0 && errno == ENOENT) {
+        LOG(ERROR) << "Couldn't access state file.";
+        return CreateResult::NOT_CREATED;
+    }
+
+    if (!NeedSnapshotsInFirstStageMount()) {
+        return CreateResult::NOT_CREATED;
+    }
+
+    auto slot_suffix = device_->GetOtherSlotSuffix();
+    auto slot_number = SlotNumberForSlotSuffix(slot_suffix);
+    auto super_path = device_->GetSuperDevice(slot_number);
+    if (!CreateLogicalAndSnapshotPartitions(super_path)) {
+        LOG(ERROR) << "Unable to map partitions.";
+        return CreateResult::ERROR;
+    }
+    return CreateResult::CREATED;
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/snapshot_test.cpp b/fs_mgr/libsnapshot/snapshot_test.cpp
index 2da0103..cea9d69 100644
--- a/fs_mgr/libsnapshot/snapshot_test.cpp
+++ b/fs_mgr/libsnapshot/snapshot_test.cpp
@@ -47,6 +47,7 @@
 using android::base::unique_fd;
 using android::dm::DeviceMapper;
 using android::dm::DmDeviceState;
+using android::fiemap::FiemapStatus;
 using android::fiemap::IImageManager;
 using android::fs_mgr::BlockDeviceInfo;
 using android::fs_mgr::CreateLogicalPartitionParams;
@@ -1585,6 +1586,29 @@
     ASSERT_THAT(merger.get(), AnyOf(UpdateState::None, UpdateState::MergeCompleted));
 }
 
+TEST_F(SnapshotUpdateTest, LowSpace) {
+    static constexpr auto kMaxFree = 10_MiB;
+    auto userdata = std::make_unique<LowSpaceUserdata>();
+    ASSERT_TRUE(userdata->Init(kMaxFree));
+
+    // Grow all partitions to 5_MiB, total 15_MiB. This requires 15 MiB of CoW space. After
+    // using the empty space in super (< 1 MiB), it uses at least 14 MiB of /userdata space.
+    constexpr uint64_t partition_size = 5_MiB;
+    SetSize(sys_, partition_size);
+    SetSize(vnd_, partition_size);
+    SetSize(prd_, partition_size);
+
+    AddOperationForPartitions();
+
+    // Execute the update.
+    ASSERT_TRUE(sm->BeginUpdate());
+    auto res = sm->CreateUpdateSnapshots(manifest_);
+    ASSERT_FALSE(res);
+    ASSERT_EQ(SnapshotManager::Return::ErrorCode::NO_SPACE, res.error_code());
+    ASSERT_GE(res.required_size(), 14_MiB);
+    ASSERT_LT(res.required_size(), 15_MiB);
+}
+
 class FlashAfterUpdateTest : public SnapshotUpdateTest,
                              public WithParamInterface<std::tuple<uint32_t, bool>> {
   public:
@@ -1700,6 +1724,55 @@
                                     "Merge"s;
                          });
 
+// Test behavior of ImageManager::Create on low space scenario. These tests assumes image manager
+// uses /data as backup device.
+class ImageManagerTest : public SnapshotTest, public WithParamInterface<uint64_t> {
+  public:
+    void SetUp() override {
+        SnapshotTest::SetUp();
+        userdata_ = std::make_unique<LowSpaceUserdata>();
+        ASSERT_TRUE(userdata_->Init(GetParam()));
+    }
+    void TearDown() override {
+        EXPECT_TRUE(!image_manager_->BackingImageExists(kImageName) ||
+                    image_manager_->DeleteBackingImage(kImageName));
+    }
+    static constexpr const char* kImageName = "my_image";
+    std::unique_ptr<LowSpaceUserdata> userdata_;
+};
+
+TEST_P(ImageManagerTest, CreateImageEnoughAvailSpace) {
+    if (userdata_->available_space() == 0) {
+        GTEST_SKIP() << "/data is full (" << userdata_->available_space()
+                     << " bytes available), skipping";
+    }
+    ASSERT_TRUE(image_manager_->CreateBackingImage(kImageName, userdata_->available_space(),
+                                                   IImageManager::CREATE_IMAGE_DEFAULT))
+            << "Should be able to create image with size = " << userdata_->available_space()
+            << " bytes";
+    ASSERT_TRUE(image_manager_->DeleteBackingImage(kImageName))
+            << "Should be able to delete created image";
+}
+
+TEST_P(ImageManagerTest, CreateImageNoSpace) {
+    uint64_t to_allocate = userdata_->free_space() + userdata_->bsize();
+    auto res = image_manager_->CreateBackingImage(kImageName, to_allocate,
+                                                  IImageManager::CREATE_IMAGE_DEFAULT);
+    ASSERT_FALSE(res) << "Should not be able to create image with size = " << to_allocate
+                      << " bytes because only " << userdata_->free_space() << " bytes are free";
+    ASSERT_EQ(FiemapStatus::ErrorCode::NO_SPACE, res.error_code()) << res.string();
+}
+
+std::vector<uint64_t> ImageManagerTestParams() {
+    std::vector<uint64_t> ret;
+    for (uint64_t size = 1_MiB; size <= 512_MiB; size *= 2) {
+        ret.push_back(size);
+    }
+    return ret;
+}
+
+INSTANTIATE_TEST_SUITE_P(ImageManagerTest, ImageManagerTest, ValuesIn(ImageManagerTestParams()));
+
 }  // namespace snapshot
 }  // namespace android
 
diff --git a/fs_mgr/libsnapshot/test_helpers.cpp b/fs_mgr/libsnapshot/test_helpers.cpp
index f7f25af..b036606 100644
--- a/fs_mgr/libsnapshot/test_helpers.cpp
+++ b/fs_mgr/libsnapshot/test_helpers.cpp
@@ -14,8 +14,11 @@
 
 #include <libsnapshot/test_helpers.h>
 
+#include <sys/statvfs.h>
+
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/strings.h>
 #include <android-base/unique_fd.h>
 #include <gtest/gtest.h>
 #include <openssl/sha.h>
@@ -167,5 +170,67 @@
     return partition_update->mutable_new_partition_info()->size();
 }
 
+AssertionResult LowSpaceUserdata::Init(uint64_t max_free_space) {
+    auto res = ReadUserdataStats();
+    if (!res) return res;
+
+    // Try to fill up the disk as much as possible until free_space_ <= max_free_space.
+    big_file_ = std::make_unique<TemporaryFile>();
+    if (big_file_->fd == -1) {
+        return AssertionFailure() << strerror(errno);
+    }
+    if (!android::base::StartsWith(big_file_->path, kUserDataDevice)) {
+        return AssertionFailure() << "Temp file allocated to " << big_file_->path << ", not in "
+                                  << kUserDataDevice;
+    }
+    uint64_t next_consume =
+            std::min(free_space_ - max_free_space, (uint64_t)std::numeric_limits<off_t>::max());
+    off_t allocated = 0;
+    while (next_consume > 0 && free_space_ > max_free_space) {
+        int status = fallocate(big_file_->fd, 0, allocated, next_consume);
+        if (status == -1 && errno == ENOSPC) {
+            next_consume /= 2;
+            continue;
+        }
+        if (status == -1) {
+            return AssertionFailure() << strerror(errno);
+        }
+        allocated += next_consume;
+
+        res = ReadUserdataStats();
+        if (!res) return res;
+    }
+
+    LOG(INFO) << allocated << " bytes allocated to " << big_file_->path;
+    initialized_ = true;
+    return AssertionSuccess();
+}
+
+AssertionResult LowSpaceUserdata::ReadUserdataStats() {
+    struct statvfs buf;
+    if (statvfs(kUserDataDevice, &buf) == -1) {
+        return AssertionFailure() << strerror(errno);
+    }
+    bsize_ = buf.f_bsize;
+    free_space_ = buf.f_bsize * buf.f_bfree;
+    available_space_ = buf.f_bsize * buf.f_bavail;
+    return AssertionSuccess();
+}
+
+uint64_t LowSpaceUserdata::free_space() const {
+    CHECK(initialized_);
+    return free_space_;
+}
+
+uint64_t LowSpaceUserdata::available_space() const {
+    CHECK(initialized_);
+    return available_space_;
+}
+
+uint64_t LowSpaceUserdata::bsize() const {
+    CHECK(initialized_);
+    return bsize_;
+}
+
 }  // namespace snapshot
 }  // namespace android
diff --git a/fs_mgr/libsnapshot/utility.cpp b/fs_mgr/libsnapshot/utility.cpp
index fa1d7f0..f01500f 100644
--- a/fs_mgr/libsnapshot/utility.cpp
+++ b/fs_mgr/libsnapshot/utility.cpp
@@ -14,12 +14,15 @@
 
 #include "utility.h"
 
+#include <errno.h>
+
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/strings.h>
 #include <fs_mgr/roots.h>
 
 using android::dm::kSectorSize;
+using android::fiemap::FiemapStatus;
 using android::fs_mgr::EnsurePathMounted;
 using android::fs_mgr::EnsurePathUnmounted;
 using android::fs_mgr::Fstab;
@@ -83,7 +86,9 @@
     }
 }
 
-bool InitializeCow(const std::string& device) {
+SnapshotManager::Return InitializeCow(const std::string& device) {
+    using Return = SnapshotManager::Return;
+
     // When the kernel creates a persistent dm-snapshot, it requires a CoW file
     // to store the modifications. The kernel interface does not specify how
     // the CoW is used, and there is no standard associated.
@@ -103,15 +108,15 @@
     android::base::unique_fd fd(open(device.c_str(), O_WRONLY | O_BINARY));
     if (fd < 0) {
         PLOG(ERROR) << "Can't open COW device: " << device;
-        return false;
+        return Return(FiemapStatus::FromErrno(errno));
     }
 
     LOG(INFO) << "Zero-filling COW device: " << device;
     if (!android::base::WriteFully(fd, zeros.data(), kDmSnapZeroFillSize)) {
         PLOG(ERROR) << "Can't zero-fill COW device for " << device;
-        return false;
+        return Return(FiemapStatus::FromErrno(errno));
     }
-    return true;
+    return Return::Ok();
 }
 
 std::unique_ptr<AutoUnmountDevice> AutoUnmountDevice::New(const std::string& path) {
diff --git a/fs_mgr/libsnapshot/utility.h b/fs_mgr/libsnapshot/utility.h
index 5cc572e..0453256 100644
--- a/fs_mgr/libsnapshot/utility.h
+++ b/fs_mgr/libsnapshot/utility.h
@@ -26,6 +26,7 @@
 #include <update_engine/update_metadata.pb.h>
 
 #include <libsnapshot/auto_device.h>
+#include <libsnapshot/snapshot.h>
 
 namespace android {
 namespace snapshot {
@@ -110,7 +111,7 @@
         android::fs_mgr::MetadataBuilder* builder, const std::string& suffix);
 
 // Initialize a device before using it as the COW device for a dm-snapshot device.
-bool InitializeCow(const std::string& device);
+SnapshotManager::Return InitializeCow(const std::string& device);
 
 // "Atomically" write string to file. This is done by a series of actions:
 // 1. Write to path + ".tmp"
diff --git a/fs_mgr/libvbmeta/Android.bp b/fs_mgr/libvbmeta/Android.bp
index 937e0f3..bceabab 100644
--- a/fs_mgr/libvbmeta/Android.bp
+++ b/fs_mgr/libvbmeta/Android.bp
@@ -37,6 +37,7 @@
 cc_test_host {
     name: "libvbmeta_test",
     static_libs: [
+        "liblog",
         "libsparse",
         "libvbmeta",
         "libz",
diff --git a/init/README.md b/init/README.md
index b8300fa..4f0a7ec 100644
--- a/init/README.md
+++ b/init/README.md
@@ -487,6 +487,25 @@
   -f: force installation of the module even if the version of the running kernel
   and the version of the kernel for which the module was compiled do not match.
 
+`interface_start <name>` \
+`interface_restart <name>` \
+`interface_stop <name>`
+> Find the service that provides the interface _name_ if it exists and run the `start`, `restart`,
+or `stop` commands on it respectively.  _name_ may be either a fully qualified HIDL name, in which
+case it is specified as `<interface>/<instance>`, or an AIDL name, in which case it is specified as
+`aidl/<interface>` for example `android.hardware.secure_element@1.1::ISecureElement/eSE1` or
+`aidl/aidl_lazy_test_1`.
+
+> Note that these commands only act on interfaces specified by the `interface` service option, not
+on interfaces registered at runtime.
+
+> Example usage of these commands: \
+`interface_start android.hardware.secure_element@1.1::ISecureElement/eSE1`
+will start the HIDL Service that provides the `android.hardware.secure_element@1.1` and `eSI1`
+instance. \
+`interface_start aidl/aidl_lazy_test_1` will start the AIDL service that
+provides the `aidl_lazy_test_1` interface.
+
 `load_system_props`
 > (This action is deprecated and no-op.)
 
@@ -700,6 +719,26 @@
   `/sys/fs/ext4/${dev.mnt.blk.<mount_point>}/` to tune the block device
   characteristics in a device agnostic manner.
 
+Init responds to properties that begin with `ctl.`.  These properties take the format of
+`ctl.<command>` and the _value_ of the system property is used as a parameter, for example:
+`SetProperty("ctl.start", "logd")` will run the `start` command on `logd`.  Note that these
+properties are only settable; they will have no value when read.
+
+`ctl.start` \
+`ctl.restart` \
+`ctl.stop`
+> These are equivalent to using the `start`, `restart`, and `stop` commands on the service specified
+by the _value_ of the property.
+
+`ctl.interface_start` \
+`ctl.interface_restart` \
+`ctl.interface_stop`
+> These are equivalent to using the `interface_start`, `interface_restart`, and `interface_stop`
+commands on the interface specified by the _value_ of the property.
+
+`ctl.sigstop_on` and `ctl.sigstop_off` will turn on or off the _sigstop_ feature for the service
+specified by the _value_ of the property.  See the _Debugging init_ section below for more details
+about this feature.
 
 Boot timing
 -----------
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 2a6df84..adcba3a 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -1119,19 +1119,28 @@
 }
 
 static Result<void> ExecVdcRebootOnFailure(const std::string& vdc_arg) {
+    bool should_reboot_into_recovery = true;
     auto reboot_reason = vdc_arg + "_failed";
+    if (android::sysprop::InitProperties::userspace_reboot_in_progress().value_or(false)) {
+        should_reboot_into_recovery = false;
+    }
 
-    auto reboot = [reboot_reason](const std::string& message) {
+    auto reboot = [reboot_reason, should_reboot_into_recovery](const std::string& message) {
         // TODO (b/122850122): support this in gsi
-        if (fscrypt_is_native() && !android::gsi::IsGsiRunning()) {
-            LOG(ERROR) << message << ": Rebooting into recovery, reason: " << reboot_reason;
-            if (auto result = reboot_into_recovery(
-                        {"--prompt_and_wipe_data", "--reason="s + reboot_reason});
-                !result) {
-                LOG(FATAL) << "Could not reboot into recovery: " << result.error();
+        if (should_reboot_into_recovery) {
+            if (fscrypt_is_native() && !android::gsi::IsGsiRunning()) {
+                LOG(ERROR) << message << ": Rebooting into recovery, reason: " << reboot_reason;
+                if (auto result = reboot_into_recovery(
+                            {"--prompt_and_wipe_data", "--reason="s + reboot_reason});
+                    !result) {
+                    LOG(FATAL) << "Could not reboot into recovery: " << result.error();
+                }
+            } else {
+                LOG(ERROR) << "Failure (reboot suppressed): " << reboot_reason;
             }
         } else {
-            LOG(ERROR) << "Failure (reboot suppressed): " << reboot_reason;
+            LOG(ERROR) << message << ": rebooting, reason: " << reboot_reason;
+            trigger_shutdown("reboot," + reboot_reason);
         }
     };
 
diff --git a/init/first_stage_mount.cpp b/init/first_stage_mount.cpp
index dccd23c..9da32e4 100644
--- a/init/first_stage_mount.cpp
+++ b/init/first_stage_mount.cpp
@@ -557,6 +557,14 @@
             continue;
         }
 
+        // Skip raw partition entries such as boot, dtbo, etc.
+        // Having emmc fstab entries allows us to probe current->vbmeta_partition
+        // in InitDevices() when they are AVB chained partitions.
+        if (current->fs_type == "emmc") {
+            ++current;
+            continue;
+        }
+
         Fstab::iterator end;
         if (!MountPartition(current, false /* erase_same_mounts */, &end)) {
             if (current->fs_mgr_flags.no_fail) {
diff --git a/init/mount_namespace.cpp b/init/mount_namespace.cpp
index 93eb244..b811622 100644
--- a/init/mount_namespace.cpp
+++ b/init/mount_namespace.cpp
@@ -35,6 +35,19 @@
 namespace init {
 namespace {
 
+static bool BindMount(const std::string& source, const std::string& mount_point,
+                      bool recursive = false) {
+    unsigned long mountflags = MS_BIND;
+    if (recursive) {
+        mountflags |= MS_REC;
+    }
+    if (mount(source.c_str(), mount_point.c_str(), nullptr, mountflags, nullptr) == -1) {
+        PLOG(ERROR) << "Failed to bind mount " << source;
+        return false;
+    }
+    return true;
+}
+
 static bool MakeShared(const std::string& mount_point, bool recursive = false) {
     unsigned long mountflags = MS_SHARED;
     if (recursive) {
@@ -47,6 +60,18 @@
     return true;
 }
 
+static bool MakeSlave(const std::string& mount_point, bool recursive = false) {
+    unsigned long mountflags = MS_SLAVE;
+    if (recursive) {
+        mountflags |= MS_REC;
+    }
+    if (mount(nullptr, mount_point.c_str(), nullptr, mountflags, nullptr) == -1) {
+        PLOG(ERROR) << "Failed to change propagation type to slave";
+        return false;
+    }
+    return true;
+}
+
 static bool MakePrivate(const std::string& mount_point, bool recursive = false) {
     unsigned long mountflags = MS_PRIVATE;
     if (recursive) {
@@ -191,6 +216,39 @@
     // namespace
     if (!(MakePrivate("/linkerconfig"))) return false;
 
+    // The two mount namespaces present challenges for scoped storage, because
+    // vold, which is responsible for most of the mounting, lives in the
+    // bootstrap mount namespace, whereas most other daemons and all apps live
+    // in the default namespace.  Scoped storage has a need for a
+    // /mnt/installer view that is a slave bind mount of /mnt/user - in other
+    // words, all mounts under /mnt/user should automatically show up under
+    // /mnt/installer. However, additional mounts done under /mnt/installer
+    // should not propagate back to /mnt/user. In a single mount namespace
+    // this is easy to achieve, by simply marking the /mnt/installer a slave
+    // bind mount. Unfortunately, if /mnt/installer is only created and
+    // bind mounted after the two namespaces are created below, we end up
+    // with the following situation:
+    // /mnt/user and /mnt/installer share the same peer group in both the
+    // bootstrap and default namespaces. Marking /mnt/installer slave in either
+    // namespace means that it won't propagate events to the /mnt/installer in
+    // the other namespace, which is still something we require - vold is the
+    // one doing the mounting under /mnt/installer, and those mounts should
+    // show up in the default namespace as well.
+    //
+    // The simplest solution is to do the bind mount before the two namespaces
+    // are created: the effect is that in both namespaces, /mnt/installer is a
+    // slave to the /mnt/user mount, and at the same time /mnt/installer in the
+    // bootstrap namespace shares a peer group with /mnt/installer in the
+    // default namespace.
+    if (!mkdir_recursive("/mnt/user", 0755)) return false;
+    if (!mkdir_recursive("/mnt/installer", 0755)) return false;
+    if (!(BindMount("/mnt/user", "/mnt/installer", true))) return false;
+    // First, make /mnt/installer a slave bind mount
+    if (!(MakeSlave("/mnt/installer"))) return false;
+    // Then, make it shared again - effectively creating a new peer group, that
+    // will be inherited by new mount namespaces.
+    if (!(MakeShared("/mnt/installer"))) return false;
+
     bootstrap_ns_fd.reset(OpenMountNamespace());
     bootstrap_ns_id = GetMountNamespaceId();
 
diff --git a/init/reboot.cpp b/init/reboot.cpp
index 225bc9c..4ee7188 100644
--- a/init/reboot.cpp
+++ b/init/reboot.cpp
@@ -860,6 +860,30 @@
     am.QueueBuiltinAction(handler, "userspace-reboot");
 }
 
+/**
+ * Check if "command" field is set in bootloader message.
+ *
+ * If "command" field is broken (contains non-printable characters prior to
+ * terminating zero), it will be zeroed.
+ *
+ * @param[in,out] boot Bootloader message (BCB) structure
+ * @return true if "command" field is already set, and false if it's empty
+ */
+static bool CommandIsPresent(bootloader_message* boot) {
+    if (boot->command[0] == '\0')
+        return false;
+
+    for (size_t i = 0; i < arraysize(boot->command); ++i) {
+        if (boot->command[i] == '\0')
+            return true;
+        if (!isprint(boot->command[i]))
+            break;
+    }
+
+    memset(boot->command, 0, sizeof(boot->command));
+    return false;
+}
+
 void HandlePowerctlMessage(const std::string& command) {
     unsigned int cmd = 0;
     std::vector<std::string> cmd_params = Split(command, ",");
@@ -912,7 +936,7 @@
                 }
                 // Update the boot command field if it's empty, and preserve
                 // the other arguments in the bootloader message.
-                if (boot.command[0] == '\0') {
+                if (!CommandIsPresent(&boot)) {
                     strlcpy(boot.command, "boot-recovery", sizeof(boot.command));
                     if (std::string err; !write_bootloader_message(boot, &err)) {
                         LOG(ERROR) << "Failed to set bootloader message: " << err;
diff --git a/init/reboot_utils.cpp b/init/reboot_utils.cpp
index dac0cf4..485188b 100644
--- a/init/reboot_utils.cpp
+++ b/init/reboot_utils.cpp
@@ -34,12 +34,16 @@
 namespace init {
 
 static std::string init_fatal_reboot_target = "bootloader";
+static bool init_fatal_panic = false;
 
 void SetFatalRebootTarget() {
     std::string cmdline;
     android::base::ReadFileToString("/proc/cmdline", &cmdline);
     cmdline = android::base::Trim(cmdline);
 
+    const char kInitFatalPanicString[] = "androidboot.init_fatal_panic=true";
+    init_fatal_panic = cmdline.find(kInitFatalPanicString) != std::string::npos;
+
     const char kRebootTargetString[] = "androidboot.init_fatal_reboot_target=";
     auto start_pos = cmdline.find(kRebootTargetString);
     if (start_pos == std::string::npos) {
@@ -133,6 +137,9 @@
     for (size_t i = 0; i < backtrace->NumFrames(); i++) {
         LOG(ERROR) << backtrace->FormatFrameData(i);
     }
+    if (init_fatal_panic) {
+        _exit(signal_number);
+    }
     RebootSystem(ANDROID_RB_RESTART2, init_fatal_reboot_target);
 }
 
diff --git a/init/sysprop/InitProperties.sysprop b/init/sysprop/InitProperties.sysprop
index c856358..b876dc0 100644
--- a/init/sysprop/InitProperties.sysprop
+++ b/init/sysprop/InitProperties.sysprop
@@ -29,7 +29,7 @@
 prop {
     api_name: "is_userspace_reboot_supported"
     type: Boolean
-    scope: System
+    scope: Public
     access: Readonly
     prop_name: "ro.init.userspace_reboot.is_supported"
     integer_as_bool: true
diff --git a/libcutils/ashmem-dev.cpp b/libcutils/ashmem-dev.cpp
index 340572c..8c232f0 100644
--- a/libcutils/ashmem-dev.cpp
+++ b/libcutils/ashmem-dev.cpp
@@ -203,19 +203,23 @@
 {
     static const std::string ashmem_device_path = get_ashmem_device_path();
 
-    int ret;
-    struct stat st;
-
     if (ashmem_device_path.empty()) {
         return -1;
     }
 
     int fd = TEMP_FAILURE_RETRY(open(ashmem_device_path.c_str(), O_RDWR | O_CLOEXEC));
+
+    // fallback for APEX w/ use_vendor on Q, which would have still used /dev/ashmem
+    if (fd < 0) {
+        fd = TEMP_FAILURE_RETRY(open("/dev/ashmem", O_RDWR | O_CLOEXEC));
+    }
+
     if (fd < 0) {
         return fd;
     }
 
-    ret = TEMP_FAILURE_RETRY(fstat(fd, &st));
+    struct stat st;
+    int ret = TEMP_FAILURE_RETRY(fstat(fd, &st));
     if (ret < 0) {
         int save_errno = errno;
         close(fd);
diff --git a/libcutils/fs_config.cpp b/libcutils/fs_config.cpp
index dc31b28..65c59bd 100644
--- a/libcutils/fs_config.cpp
+++ b/libcutils/fs_config.cpp
@@ -196,10 +196,6 @@
     { 00750, AID_ROOT,      AID_SHELL,     CAP_MASK_LONG(CAP_SETUID) |
                                            CAP_MASK_LONG(CAP_SETGID),
                                               "system/bin/simpleperf_app_runner" },
-
-    // Support FIFO scheduling mode in SurfaceFlinger.
-    { 00755, AID_SYSTEM,    AID_GRAPHICS,  CAP_MASK_LONG(CAP_SYS_NICE),
-                                              "system/bin/surfaceflinger" },
     // generic defaults
     { 00755, AID_ROOT,      AID_ROOT,      0, "bin/*" },
     { 00640, AID_ROOT,      AID_SHELL,     0, "fstab.*" },
diff --git a/libcutils/include/cutils/trace.h b/libcutils/include/cutils/trace.h
index 79b4b35..e12c32c 100644
--- a/libcutils/include/cutils/trace.h
+++ b/libcutils/include/cutils/trace.h
@@ -25,7 +25,6 @@
 #include <sys/cdefs.h>
 #include <sys/types.h>
 #include <unistd.h>
-
 #include <cutils/compiler.h>
 
 __BEGIN_DECLS
@@ -89,6 +88,12 @@
 #error ATRACE_TAG must be defined to be one of the tags defined in cutils/trace.h
 #endif
 
+// Set this to 0 to revert to the old Binder-based atrace implementation.
+// This is only here in case rollbacks do not apply cleanly.
+// TODO(fmayer): Remove this once we are confident this won't need to be
+// rolled back, no later than 2020-03-01.
+#define ATRACE_SHMEM 1
+
 /**
  * Opens the trace file for writing and reads the property for initial tags.
  * The atrace.tags.enableflags property sets the tags to trace.
@@ -116,11 +121,15 @@
  * prevent tracing within the Zygote process.
  */
 void atrace_set_tracing_enabled(bool enabled);
-
 /**
- * Flag indicating whether setup has been completed, initialized to 0.
- * Nonzero indicates setup has completed.
- * Note: This does NOT indicate whether or not setup was successful.
+ * If !ATRACE_SHMEM:
+ *   Flag indicating whether setup has been completed, initialized to 0.
+ *   Nonzero indicates setup has completed.
+ *   Note: This does NOT indicate whether or not setup was successful.
+ * If ATRACE_SHMEM:
+ *   This is always set to false. This forces code that uses an old version
+ *   of this header to always call into atrace_setup, in which we call
+ *   atrace_init unconditionally.
  */
 extern atomic_bool atrace_is_ready;
 
@@ -143,6 +152,12 @@
  * This can be explicitly run to avoid setup delay on first trace function.
  */
 #define ATRACE_INIT() atrace_init()
+#define ATRACE_GET_ENABLED_TAGS() atrace_get_enabled_tags()
+
+#if ATRACE_SHMEM
+void atrace_init();
+uint64_t atrace_get_enabled_tags();
+#else
 static inline void atrace_init()
 {
     if (CC_UNLIKELY(!atomic_load_explicit(&atrace_is_ready, memory_order_acquire))) {
@@ -155,12 +170,12 @@
  * It can be used as a guard condition around more expensive trace calculations.
  * Every trace function calls this, which ensures atrace_init is run.
  */
-#define ATRACE_GET_ENABLED_TAGS() atrace_get_enabled_tags()
 static inline uint64_t atrace_get_enabled_tags()
 {
     atrace_init();
     return atrace_enabled_tags;
 }
+#endif
 
 /**
  * Test if a given tag is currently enabled.
diff --git a/libcutils/trace-container.cpp b/libcutils/trace-container.cpp
index d981f8f..c23d5e2 100644
--- a/libcutils/trace-container.cpp
+++ b/libcutils/trace-container.cpp
@@ -39,6 +39,11 @@
 static pthread_mutex_t  atrace_enabling_mutex        = PTHREAD_MUTEX_INITIALIZER;
 static pthread_rwlock_t atrace_container_sock_rwlock = PTHREAD_RWLOCK_INITIALIZER;
 
+static void atrace_seq_number_changed(uint32_t, uint32_t seq_no) {
+    pthread_once(&atrace_once_control, atrace_init_once);
+    atomic_store_explicit(&last_sequence_number, seq_no, memory_order_relaxed);
+}
+
 static bool atrace_init_container_sock()
 {
     pthread_rwlock_wrlock(&atrace_container_sock_rwlock);
diff --git a/libcutils/trace-dev.cpp b/libcutils/trace-dev.cpp
index bff16c1..2ee39d3 100644
--- a/libcutils/trace-dev.cpp
+++ b/libcutils/trace-dev.cpp
@@ -37,12 +37,39 @@
     } else {
       atrace_enabled_tags = atrace_get_property();
     }
+#if !ATRACE_SHMEM
     atomic_store_explicit(&atrace_is_ready, true, memory_order_release);
+#endif
+}
+
+static void atrace_seq_number_changed(uint32_t prev_seq_no, uint32_t seq_no) {
+    if (!atomic_load_explicit(&atrace_is_enabled, memory_order_acquire)) {
+        return;
+    }
+
+    // Someone raced us.
+    if (!atomic_compare_exchange_strong(&last_sequence_number, &prev_seq_no, seq_no)) {
+        return;
+    }
+
+    if (CC_UNLIKELY(prev_seq_no == kSeqNoNotInit)) {
+#if defined(__BIONIC__)
+        const prop_info* new_pi = __system_property_find("debug.atrace.tags.enableflags");
+        if (new_pi) atrace_property_info = new_pi;
+#endif
+        pthread_once(&atrace_once_control, atrace_init_once);
+    }
+
+    atrace_update_tags();
 }
 
 void atrace_setup()
 {
+#if ATRACE_SHMEM
+    atrace_init();
+#else
     pthread_once(&atrace_once_control, atrace_init_once);
+#endif
 }
 
 void atrace_begin_body(const char* name)
diff --git a/libcutils/trace-dev.inc b/libcutils/trace-dev.inc
index e3da77b..a57a4c5 100644
--- a/libcutils/trace-dev.inc
+++ b/libcutils/trace-dev.inc
@@ -34,6 +34,11 @@
 #include <log/log.h>
 #include <log/log_properties.h>
 
+#if defined(__BIONIC__)
+#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
+#include <sys/_system_properties.h>
+#endif
+
 /**
  * Maximum size of a message that can be logged to the trace buffer.
  * Note this message includes a tag, the pid, and the string given as the name.
@@ -41,12 +46,57 @@
  */
 #define ATRACE_MESSAGE_LENGTH 1024
 
-atomic_bool             atrace_is_ready      = ATOMIC_VAR_INIT(false);
-int                     atrace_marker_fd     = -1;
-uint64_t                atrace_enabled_tags  = ATRACE_TAG_NOT_READY;
-static bool             atrace_is_debuggable = false;
-static atomic_bool      atrace_is_enabled    = ATOMIC_VAR_INIT(true);
-static pthread_mutex_t  atrace_tags_mutex    = PTHREAD_MUTEX_INITIALIZER;
+constexpr uint32_t kSeqNoNotInit = static_cast<uint32_t>(-1);
+
+atomic_bool              atrace_is_ready      = ATOMIC_VAR_INIT(false);
+int                      atrace_marker_fd     = -1;
+uint64_t                 atrace_enabled_tags  = ATRACE_TAG_NOT_READY;
+static bool              atrace_is_debuggable = false;
+static atomic_bool       atrace_is_enabled    = ATOMIC_VAR_INIT(true);
+static pthread_mutex_t   atrace_tags_mutex    = PTHREAD_MUTEX_INITIALIZER;
+
+/**
+ * Sequence number of debug.atrace.tags.enableflags the last time the enabled
+ * tags were reloaded.
+ **/
+static _Atomic(uint32_t) last_sequence_number = ATOMIC_VAR_INIT(kSeqNoNotInit);
+
+#if defined(__BIONIC__)
+// All zero prop_info that has a sequence number of 0. This is easier than
+// depending on implementation details of the property implementation.
+//
+// prop_info is static_assert-ed to be 96 bytes, which cannot change due to
+// ABI compatibility.
+alignas(uint64_t) static char empty_pi[96];
+static const prop_info* atrace_property_info = reinterpret_cast<const prop_info*>(empty_pi);
+#endif
+
+#if ATRACE_SHMEM
+
+/**
+ * This is called when the sequence number of debug.atrace.tags.enableflags
+ * changes and we need to reload the enabled tags.
+ **/
+static void atrace_seq_number_changed(uint32_t prev_seq_no, uint32_t seq_no);
+
+void atrace_init() {
+#if defined(__BIONIC__)
+    uint32_t seq_no = __system_property_serial(atrace_property_info);  // Acquire semantics.
+#else
+    uint32_t seq_no = 0;
+#endif
+    uint32_t prev_seq_no = atomic_load_explicit(&last_sequence_number, memory_order_relaxed);
+    if (CC_UNLIKELY(seq_no != prev_seq_no)) {
+        atrace_seq_number_changed(prev_seq_no, seq_no);
+    }
+}
+
+uint64_t atrace_get_enabled_tags()
+{
+    atrace_init();
+    return atrace_enabled_tags;
+}
+#endif
 
 // Set whether this process is debuggable, which determines whether
 // application-level tracing is allowed when the ro.debuggable system property
@@ -136,7 +186,7 @@
 void atrace_update_tags()
 {
     uint64_t tags;
-    if (CC_UNLIKELY(atomic_load_explicit(&atrace_is_ready, memory_order_acquire))) {
+    if (ATRACE_SHMEM || CC_UNLIKELY(atomic_load_explicit(&atrace_is_ready, memory_order_acquire))) {
         if (atomic_load_explicit(&atrace_is_enabled, memory_order_acquire)) {
             tags = atrace_get_property();
             pthread_mutex_lock(&atrace_tags_mutex);
diff --git a/libcutils/trace-host.cpp b/libcutils/trace-host.cpp
index d47cc18..c21d0ee 100644
--- a/libcutils/trace-host.cpp
+++ b/libcutils/trace-host.cpp
@@ -30,3 +30,10 @@
 void atrace_async_end_body(const char* /*name*/, int32_t /*cookie*/) {}
 void atrace_int_body(const char* /*name*/, int32_t /*value*/) {}
 void atrace_int64_body(const char* /*name*/, int64_t /*value*/) {}
+#if ATRACE_SHMEM
+void atrace_init() {}
+uint64_t atrace_get_enabled_tags()
+{
+    return ATRACE_TAG_NOT_READY;
+}
+#endif
diff --git a/liblog/event_tag_map.cpp b/liblog/event_tag_map.cpp
index 2886289..51c5e60 100644
--- a/liblog/event_tag_map.cpp
+++ b/liblog/event_tag_map.cpp
@@ -36,7 +36,6 @@
 #include <utils/FastStrcmp.h>
 #include <utils/RWLock.h>
 
-#include "log_portability.h"
 #include "logd_reader.h"
 
 #define OUT_TAG "EventTagMap"
diff --git a/liblog/fake_log_device.cpp b/liblog/fake_log_device.cpp
index 2ec6393..2582cea 100644
--- a/liblog/fake_log_device.cpp
+++ b/liblog/fake_log_device.cpp
@@ -36,7 +36,6 @@
 #include <log/log_id.h>
 #include <log/logprint.h>
 
-#include "log_portability.h"
 #include "logger.h"
 
 #define kMaxTagLen 16 /* from the long-dead utils/Log.cpp */
@@ -49,14 +48,6 @@
 #define TRACE(...) ((void)0)
 #endif
 
-static void FakeClose();
-static int FakeWrite(log_id_t log_id, struct timespec* ts, struct iovec* vec, size_t nr);
-
-struct android_log_transport_write fakeLoggerWrite = {
-    .close = FakeClose,
-    .write = FakeWrite,
-};
-
 typedef struct LogState {
   bool initialized = false;
   /* global minimum priority */
@@ -453,7 +444,7 @@
  *  tag (N bytes -- null-terminated ASCII string)
  *  message (N bytes -- null-terminated ASCII string)
  */
-static int FakeWrite(log_id_t log_id, struct timespec*, struct iovec* vector, size_t count) {
+int FakeWrite(log_id_t log_id, struct timespec*, struct iovec* vector, size_t count) {
   /* Make sure that no-one frees the LogState while we're using it.
    * Also guarantees that only one thread is in showLog() at a given
    * time (if it matters).
@@ -519,7 +510,7 @@
  * call is in the exit handler. Logging can continue in the exit handler to
  * help debug HOST tools ...
  */
-static void FakeClose() {
+void FakeClose() {
   auto lock = std::lock_guard{*fake_log_mutex};
 
   memset(&log_state, 0, sizeof(log_state));
diff --git a/liblog/fake_log_device.h b/liblog/fake_log_device.h
index bd2256c..53f1b41 100644
--- a/liblog/fake_log_device.h
+++ b/liblog/fake_log_device.h
@@ -16,18 +16,15 @@
 
 #pragma once
 
+#include <sys/cdefs.h>
 #include <sys/types.h>
 
-#include "log_portability.h"
-#include "uio.h"
-
-struct iovec;
+#include <android/log.h>
 
 __BEGIN_DECLS
 
-int fakeLogOpen(const char* pathName);
-int fakeLogClose(int fd);
-ssize_t fakeLogWritev(int fd, const struct iovec* vector, int count);
+void FakeClose();
+int FakeWrite(log_id_t log_id, struct timespec* ts, struct iovec* vec, size_t nr);
 
 int __android_log_is_loggable(int prio, const char*, int def);
 int __android_log_is_loggable_len(int prio, const char*, size_t, int def);
diff --git a/liblog/log_event_list.cpp b/liblog/log_event_list.cpp
index e9f4a32..cb70d48 100644
--- a/liblog/log_event_list.cpp
+++ b/liblog/log_event_list.cpp
@@ -25,8 +25,6 @@
 #include <log/log_event_list.h>
 #include <private/android_logger.h>
 
-#include "log_portability.h"
-
 #define MAX_EVENT_PAYLOAD (LOGGER_ENTRY_MAX_PAYLOAD - sizeof(int32_t))
 
 enum ReadWriteFlag {
diff --git a/liblog/log_event_write.cpp b/liblog/log_event_write.cpp
index d04ba90..39afd0c 100644
--- a/liblog/log_event_write.cpp
+++ b/liblog/log_event_write.cpp
@@ -20,8 +20,6 @@
 #include <log/log.h>
 #include <log/log_event_list.h>
 
-#include "log_portability.h"
-
 #define MAX_SUBTAG_LEN 32
 
 int __android_log_error_write(int tag, const char* subTag, int32_t uid, const char* data,
diff --git a/liblog/log_portability.h b/liblog/log_portability.h
deleted file mode 100644
index b7279d1..0000000
--- a/liblog/log_portability.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (C) 2016 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 <sys/cdefs.h>
-#include <unistd.h>
-
-/* possible missing definitions in sys/cdefs.h */
-
-/* DECLS */
-#ifndef __BEGIN_DECLS
-#if defined(__cplusplus)
-#define __BEGIN_DECLS extern "C" {
-#define __END_DECLS }
-#else
-#define __BEGIN_DECLS
-#define __END_DECLS
-#endif
-#endif
-
-/* possible missing definitions in unistd.h */
-
-#ifndef TEMP_FAILURE_RETRY
-/* Used to retry syscalls that can return EINTR. */
-#define TEMP_FAILURE_RETRY(exp)            \
-  ({                                       \
-    __typeof__(exp) _rc;                   \
-    do {                                   \
-      _rc = (exp);                         \
-    } while (_rc == -1 && errno == EINTR); \
-    _rc;                                   \
-  })
-#endif
diff --git a/liblog/log_time.cpp b/liblog/log_time.cpp
index 3ae250f..3fbe1cb 100644
--- a/liblog/log_time.cpp
+++ b/liblog/log_time.cpp
@@ -21,8 +21,6 @@
 
 #include <private/android_logger.h>
 
-#include "log_portability.h"
-
 const char log_time::default_format[] = "%m-%d %H:%M:%S.%q";
 const timespec log_time::EPOCH = {0, 0};
 
diff --git a/liblog/logd_reader.cpp b/liblog/logd_reader.cpp
index 6865c14..82ed6b2 100644
--- a/liblog/logd_reader.cpp
+++ b/liblog/logd_reader.cpp
@@ -35,8 +35,6 @@
 
 #include <string>
 
-#include <cutils/sockets.h>
-#include <private/android_filesystem_config.h>
 #include <private/android_logger.h>
 
 #include "logger.h"
diff --git a/liblog/logd_reader.h b/liblog/logd_reader.h
index 2d032fa..68eef02 100644
--- a/liblog/logd_reader.h
+++ b/liblog/logd_reader.h
@@ -16,10 +16,10 @@
 
 #pragma once
 
+#include <sys/cdefs.h>
 #include <unistd.h>
 
 #include "log/log_read.h"
-#include "log_portability.h"
 
 __BEGIN_DECLS
 
diff --git a/liblog/logd_writer.cpp b/liblog/logd_writer.cpp
index 3c6eb69..67376f4 100644
--- a/liblog/logd_writer.cpp
+++ b/liblog/logd_writer.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include "logd_writer.h"
+
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
@@ -32,23 +34,13 @@
 
 #include <shared_mutex>
 
-#include <cutils/sockets.h>
 #include <private/android_filesystem_config.h>
 #include <private/android_logger.h>
 
-#include "log_portability.h"
 #include "logger.h"
 #include "rwlock.h"
 #include "uio.h"
 
-static int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr);
-static void LogdClose();
-
-struct android_log_transport_write logdLoggerWrite = {
-    .close = LogdClose,
-    .write = LogdWrite,
-};
-
 static int logd_socket;
 static RwLock logd_socket_lock;
 
@@ -90,7 +82,7 @@
   OpenSocketLocked();
 }
 
-static void LogdClose() {
+void LogdClose() {
   auto lock = std::unique_lock{logd_socket_lock};
   if (logd_socket > 0) {
     close(logd_socket);
@@ -98,7 +90,7 @@
   logd_socket = 0;
 }
 
-static int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) {
+int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) {
   ssize_t ret;
   static const unsigned headerLength = 1;
   struct iovec newVec[nr + headerLength];
@@ -119,7 +111,7 @@
   }
 
   /* logd, after initialization and priv drop */
-  if (__android_log_uid() == AID_LOGD) {
+  if (getuid() == AID_LOGD) {
     /*
      * ignore log messages we send to ourself (logd).
      * Such log messages are often generated by libraries we depend on
diff --git a/liblog/logd_writer.h b/liblog/logd_writer.h
new file mode 100644
index 0000000..41197b5
--- /dev/null
+++ b/liblog/logd_writer.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2020 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 <stddef.h>
+
+#include <android/log.h>
+
+int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr);
+void LogdClose();
diff --git a/liblog/logger.h b/liblog/logger.h
index 40d5fe5..ddff19d 100644
--- a/liblog/logger.h
+++ b/liblog/logger.h
@@ -17,22 +17,14 @@
 #pragma once
 
 #include <stdatomic.h>
+#include <sys/cdefs.h>
 
-#include <cutils/list.h>
 #include <log/log.h>
 
-#include "log_portability.h"
 #include "uio.h"
 
 __BEGIN_DECLS
 
-struct android_log_transport_write {
-  void (*close)(); /* free up resources */
-  /* write log to transport, returns number of bytes propagated, or -errno */
-  int (*write)(log_id_t logId, struct timespec* ts, struct iovec* vec,
-               size_t nr);
-};
-
 struct logger_list {
   atomic_int fd;
   int mode;
@@ -56,18 +48,4 @@
   return reinterpret_cast<uintptr_t>(logger) & LOGGER_LOGD;
 }
 
-/* OS specific dribs and drabs */
-
-#if defined(_WIN32)
-#include <private/android_filesystem_config.h>
-typedef uint32_t uid_t;
-static inline uid_t __android_log_uid() {
-  return AID_SYSTEM;
-}
-#else
-static inline uid_t __android_log_uid() {
-  return getuid();
-}
-#endif
-
 __END_DECLS
diff --git a/liblog/logger_name.cpp b/liblog/logger_name.cpp
index ece0550..7d676f4 100644
--- a/liblog/logger_name.cpp
+++ b/liblog/logger_name.cpp
@@ -19,8 +19,6 @@
 
 #include <log/log.h>
 
-#include "log_portability.h"
-
 /* In the future, we would like to make this list extensible */
 static const char* LOG_NAME[LOG_ID_MAX] = {
     /* clang-format off */
diff --git a/liblog/logger_read.cpp b/liblog/logger_read.cpp
index 0d383ff..e0598de 100644
--- a/liblog/logger_read.cpp
+++ b/liblog/logger_read.cpp
@@ -27,10 +27,7 @@
 #include <unistd.h>
 
 #include <android/log.h>
-#include <cutils/list.h>
-#include <private/android_filesystem_config.h>
 
-#include "log_portability.h"
 #include "logd_reader.h"
 #include "logger.h"
 #include "pmsg_reader.h"
diff --git a/liblog/logger_write.cpp b/liblog/logger_write.cpp
index d38b402..d6ef951 100644
--- a/liblog/logger_write.cpp
+++ b/liblog/logger_write.cpp
@@ -15,7 +15,6 @@
  */
 
 #include <errno.h>
-#include <stdatomic.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/time.h>
@@ -24,31 +23,25 @@
 #include <android/set_abort_message.h>
 #endif
 
+#include <android-base/macros.h>
 #include <private/android_filesystem_config.h>
 #include <private/android_logger.h>
 
-#include "log_portability.h"
 #include "logger.h"
 #include "uio.h"
 
-#define LOG_BUF_SIZE 1024
-
 #if (FAKE_LOG_DEVICE == 0)
-extern struct android_log_transport_write logdLoggerWrite;
-extern struct android_log_transport_write pmsgLoggerWrite;
-
-android_log_transport_write* android_log_write = &logdLoggerWrite;
-android_log_transport_write* android_log_persist_write = &pmsgLoggerWrite;
+#include "logd_writer.h"
+#include "pmsg_writer.h"
 #else
-extern android_log_transport_write fakeLoggerWrite;
-
-android_log_transport_write* android_log_write = &fakeLoggerWrite;
-android_log_transport_write* android_log_persist_write = nullptr;
+#include "fake_log_device.h"
 #endif
 
+#define LOG_BUF_SIZE 1024
+
 #if defined(__ANDROID__)
 static int check_log_uid_permissions() {
-  uid_t uid = __android_log_uid();
+  uid_t uid = getuid();
 
   /* Matches clientHasLogCredentials() in logd */
   if ((uid != AID_SYSTEM) && (uid != AID_ROOT) && (uid != AID_LOG)) {
@@ -92,14 +85,12 @@
  * Release any logger resources. A new log write will immediately re-acquire.
  */
 void __android_log_close() {
-  if (android_log_write != nullptr) {
-    android_log_write->close();
-  }
-
-  if (android_log_persist_write != nullptr) {
-    android_log_persist_write->close();
-  }
-
+#if (FAKE_LOG_DEVICE == 0)
+  LogdClose();
+  PmsgClose();
+#else
+  FakeClose();
+#endif
 }
 
 static int write_to_log(log_id_t log_id, struct iovec* vec, size_t nr) {
@@ -158,17 +149,12 @@
 
   ret = 0;
 
-  if (android_log_write != nullptr) {
-    ssize_t retval;
-    retval = android_log_write->write(log_id, &ts, vec, nr);
-    if (ret >= 0) {
-      ret = retval;
-    }
-  }
-
-  if (android_log_persist_write != nullptr) {
-    android_log_persist_write->write(log_id, &ts, vec, nr);
-  }
+#if (FAKE_LOG_DEVICE == 0)
+  ret = LogdWrite(log_id, &ts, vec, nr);
+  PmsgWrite(log_id, &ts, vec, nr);
+#else
+  ret = FakeWrite(log_id, &ts, vec, nr);
+#endif
 
   errno = save_errno;
   return ret;
diff --git a/liblog/logprint.cpp b/liblog/logprint.cpp
index 4b61828..0745a1e 100644
--- a/liblog/logprint.cpp
+++ b/liblog/logprint.cpp
@@ -40,8 +40,6 @@
 #include <log/logprint.h>
 #include <private/android_logger.h>
 
-#include "log_portability.h"
-
 #define MS_PER_NSEC 1000000
 #define US_PER_NSEC 1000
 
diff --git a/liblog/pmsg_reader.cpp b/liblog/pmsg_reader.cpp
index 9390fec..64a92b7 100644
--- a/liblog/pmsg_reader.cpp
+++ b/liblog/pmsg_reader.cpp
@@ -23,7 +23,7 @@
 #include <string.h>
 #include <sys/types.h>
 
-#include <private/android_filesystem_config.h>
+#include <cutils/list.h>
 #include <private/android_logger.h>
 
 #include "logger.h"
diff --git a/liblog/pmsg_reader.h b/liblog/pmsg_reader.h
index 53746d8..b784f9f 100644
--- a/liblog/pmsg_reader.h
+++ b/liblog/pmsg_reader.h
@@ -16,10 +16,10 @@
 
 #pragma once
 
+#include <sys/cdefs.h>
 #include <unistd.h>
 
 #include "log/log_read.h"
-#include "log_portability.h"
 
 __BEGIN_DECLS
 
diff --git a/liblog/pmsg_writer.cpp b/liblog/pmsg_writer.cpp
index 4f45780..06e5e04 100644
--- a/liblog/pmsg_writer.cpp
+++ b/liblog/pmsg_writer.cpp
@@ -14,9 +14,7 @@
  * limitations under the License.
  */
 
-/*
- * pmsg write handler
- */
+#include "pmsg_writer.h"
 
 #include <errno.h>
 #include <fcntl.h>
@@ -28,22 +26,12 @@
 #include <shared_mutex>
 
 #include <log/log_properties.h>
-#include <private/android_filesystem_config.h>
 #include <private/android_logger.h>
 
-#include "log_portability.h"
 #include "logger.h"
 #include "rwlock.h"
 #include "uio.h"
 
-static void PmsgClose();
-static int PmsgWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr);
-
-struct android_log_transport_write pmsgLoggerWrite = {
-    .close = PmsgClose,
-    .write = PmsgWrite,
-};
-
 static int pmsg_fd;
 static RwLock pmsg_fd_lock;
 
@@ -57,7 +45,7 @@
   pmsg_fd = TEMP_FAILURE_RETRY(open("/dev/pmsg0", O_WRONLY | O_CLOEXEC));
 }
 
-static void PmsgClose() {
+void PmsgClose() {
   auto lock = std::unique_lock{pmsg_fd_lock};
   if (pmsg_fd > 0) {
     close(pmsg_fd);
@@ -65,7 +53,7 @@
   pmsg_fd = 0;
 }
 
-static int PmsgWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) {
+int PmsgWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) {
   static const unsigned headerLength = 2;
   struct iovec newVec[nr + headerLength];
   android_log_header_t header;
@@ -123,7 +111,7 @@
 
   pmsgHeader.magic = LOGGER_MAGIC;
   pmsgHeader.len = sizeof(pmsgHeader) + sizeof(header);
-  pmsgHeader.uid = __android_log_uid();
+  pmsgHeader.uid = getuid();
   pmsgHeader.pid = getpid();
 
   header.id = logId;
diff --git a/liblog/pmsg_writer.h b/liblog/pmsg_writer.h
new file mode 100644
index 0000000..d5e1a1c
--- /dev/null
+++ b/liblog/pmsg_writer.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2020 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 <stddef.h>
+
+#include <android/log.h>
+
+int PmsgWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr);
+void PmsgClose();
diff --git a/liblog/properties.cpp b/liblog/properties.cpp
index 2e0a8c9..2b2327c 100644
--- a/liblog/properties.cpp
+++ b/liblog/properties.cpp
@@ -26,8 +26,6 @@
 
 #include <private/android_logger.h>
 
-#include "log_portability.h"
-
 static pthread_mutex_t lock_loggable = PTHREAD_MUTEX_INITIALIZER;
 
 static int lock() {
diff --git a/libutils/include/utils/Flattenable.h b/libutils/include/utils/Flattenable.h
index 953b859..17c5e10 100644
--- a/libutils/include/utils/Flattenable.h
+++ b/libutils/include/utils/Flattenable.h
@@ -52,7 +52,12 @@
 
     template<size_t N>
     static size_t align(void*& buffer) {
-        return align<N>( const_cast<void const*&>(buffer) );
+        static_assert(!(N & (N - 1)), "Can only align to a power of 2.");
+        void* b = buffer;
+        buffer = reinterpret_cast<void*>((uintptr_t(buffer) + (N-1)) & ~(N-1));
+        size_t delta = size_t(uintptr_t(buffer) - uintptr_t(b));
+        memset(b, 0, delta);
+        return delta;
     }
 
     static void advance(void*& buffer, size_t& size, size_t offset) {
diff --git a/libvndksupport/Android.bp b/libvndksupport/Android.bp
index f4544a1..b92c76c 100644
--- a/libvndksupport/Android.bp
+++ b/libvndksupport/Android.bp
@@ -1,5 +1,3 @@
-subdirs = ["tests"]
-
 cc_library {
     name: "libvndksupport",
     native_bridge_supported: true,
diff --git a/property_service/Android.bp b/property_service/Android.bp
deleted file mode 100644
index b44c296..0000000
--- a/property_service/Android.bp
+++ /dev/null
@@ -1 +0,0 @@
-subdirs = ["*"]
diff --git a/property_service/property_info_checker/Android.bp b/property_service/property_info_checker/Android.bp
index 7d66199..65e660a 100644
--- a/property_service/property_info_checker/Android.bp
+++ b/property_service/property_info_checker/Android.bp
@@ -7,6 +7,7 @@
         "libpropertyinfoserializer",
         "libpropertyinfoparser",
         "libbase",
+        "liblog",
         "libsepol",
     ],
     srcs: ["property_info_checker.cpp"],
diff --git a/rootdir/init.rc b/rootdir/init.rc
index 7a3339d..00053ad 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -42,6 +42,10 @@
     mkdir /linkerconfig/bootstrap 0755
     mkdir /linkerconfig/default 0755
 
+    # Disable dm-verity hash prefetching, since it doesn't help performance
+    # Read more in b/136247322
+    write /sys/module/dm_verity/parameters/prefetch_cluster 0
+
     # Generate ld.config.txt for early executed processes
     exec -- /system/bin/linkerconfig --target /linkerconfig/bootstrap
     chmod 644 /linkerconfig/bootstrap/ld.config.txt
@@ -584,7 +588,7 @@
     # profile file layout
     mkdir /data/misc/profiles 0771 system system
     mkdir /data/misc/profiles/cur 0771 system system
-    mkdir /data/misc/profiles/ref 0771 system system
+    mkdir /data/misc/profiles/ref 0770 system system
     mkdir /data/misc/profman 0770 system shell
     mkdir /data/misc/gcov 0770 root root
     mkdir /data/misc/installd 0700 root root
@@ -691,6 +695,10 @@
     mount none /data/user /data_mirror/data_ce/null bind rec
     mount none /data/user_de /data_mirror/data_de/null bind rec
 
+    # Create mirror directory for jit profiles
+    mkdir /data_mirror/cur_profiles 0700 root root
+    mount none /data/misc/profiles/cur /data_mirror/cur_profiles bind rec
+
     mkdir /data/cache 0770 system cache encryption=Require
     mkdir /data/cache/recovery 0770 system cache
     mkdir /data/cache/backup_stage 0700 system system
@@ -701,7 +709,7 @@
     mkdir /data/rollback-observer 0700 system system encryption=DeleteIfNecessary
 
     # Create root dir for Incremental Service
-    mkdir /data/incremental 0770 system system encryption=None
+    mkdir /data/incremental 0771 system system encryption=Require
 
     # Wait for apexd to finish activating APEXes before starting more processes.
     wait_for_prop apexd.status ready
diff --git a/storaged/main.cpp b/storaged/main.cpp
index 3817fb5..e35bd6f 100644
--- a/storaged/main.cpp
+++ b/storaged/main.cpp
@@ -51,7 +51,7 @@
     storaged_sp->init();
     storaged_sp->report_storage_info();
 
-    LOG_TO(SYSTEM, INFO) << "storaged: Start";
+    LOG(INFO) << "storaged: Start";
 
     for (;;) {
         storaged_sp->event_checked();
@@ -76,6 +76,8 @@
     bool flag_dump_perf = false;
     int opt;
 
+    android::base::InitLogging(argv, android::base::LogdLogger(android::base::SYSTEM));
+
     for (;;) {
         int opt_idx = 0;
         static struct option long_options[] = {
@@ -124,13 +126,13 @@
         pthread_t storaged_main_thread;
         errno = pthread_create(&storaged_main_thread, NULL, storaged_main, NULL);
         if (errno != 0) {
-            PLOG_TO(SYSTEM, ERROR) << "Failed to create main thread";
+            PLOG(ERROR) << "Failed to create main thread";
             return -1;
         }
 
         if (StoragedService::start() != android::OK ||
             StoragedPrivateService::start() != android::OK) {
-            PLOG_TO(SYSTEM, ERROR) << "Failed to start storaged service";
+            PLOG(ERROR) << "Failed to start storaged service";
             return -1;
         }
 
diff --git a/storaged/storaged.cpp b/storaged/storaged.cpp
index 1d934a2..573b8c5 100644
--- a/storaged/storaged.cpp
+++ b/storaged/storaged.cpp
@@ -97,25 +97,23 @@
 
     health = get_health_service();
     if (health == NULL) {
-        LOG_TO(SYSTEM, WARNING) << "health: failed to find IHealth service";
+        LOG(WARNING) << "health: failed to find IHealth service";
         return;
     }
 
     BatteryStatus status = BatteryStatus::UNKNOWN;
     auto ret = health->getChargeStatus([&](Result r, BatteryStatus v) {
         if (r != Result::SUCCESS) {
-            LOG_TO(SYSTEM, WARNING)
-                << "health: cannot get battery status " << toString(r);
+            LOG(WARNING) << "health: cannot get battery status " << toString(r);
             return;
         }
         if (v == BatteryStatus::UNKNOWN) {
-            LOG_TO(SYSTEM, WARNING) << "health: invalid battery status";
+            LOG(WARNING) << "health: invalid battery status";
         }
         status = v;
     });
     if (!ret.isOk()) {
-        LOG_TO(SYSTEM, WARNING) << "health: get charge status transaction error "
-            << ret.description();
+        LOG(WARNING) << "health: get charge status transaction error " << ret.description();
     }
 
     mUidm.init(is_charger_on(status));
@@ -126,11 +124,11 @@
 
 void storaged_t::serviceDied(uint64_t cookie, const wp<::android::hidl::base::V1_0::IBase>& who) {
     if (health != NULL && interfacesEqual(health, who.promote())) {
-        LOG_TO(SYSTEM, ERROR) << "health service died, exiting";
+        LOG(ERROR) << "health service died, exiting";
         android::hardware::IPCThreadState::self()->stopProcess();
         exit(1);
     } else {
-        LOG_TO(SYSTEM, ERROR) << "unknown service died";
+        LOG(ERROR) << "unknown service died";
     }
 }
 
@@ -192,7 +190,7 @@
         reinterpret_cast<const Bytef*>(uid_io_usage.SerializeAsString().c_str()),
         uid_io_usage.ByteSize());
     if (proto.crc() != computed_crc) {
-        LOG_TO(SYSTEM, WARNING) << "CRC mismatch in " << proto_file;
+        LOG(WARNING) << "CRC mismatch in " << proto_file;
         return;
     }
 
@@ -228,8 +226,7 @@
     char* data = nullptr;
     if (posix_memalign(reinterpret_cast<void**>(&data),
                        pagesize, proto->ByteSize())) {
-        PLOG_TO(SYSTEM, ERROR) << "Faied to alloc aligned buffer (size: "
-                               << proto->ByteSize() << ")";
+        PLOG(ERROR) << "Faied to alloc aligned buffer (size: " << proto->ByteSize() << ")";
         return data;
     }
 
@@ -246,7 +243,7 @@
                     (user_id == USER_SYSTEM ? O_DIRECT : 0),
                  S_IRUSR | S_IWUSR)));
     if (fd == -1) {
-        PLOG_TO(SYSTEM, ERROR) << "Faied to open tmp file: " << tmp_file;
+        PLOG(ERROR) << "Faied to open tmp file: " << tmp_file;
         return;
     }
 
@@ -261,7 +258,7 @@
             start = steady_clock::now();
             ret = write(fd, data, MIN(benchmark_unit_size, size));
             if (ret <= 0) {
-                PLOG_TO(SYSTEM, ERROR) << "Faied to write tmp file: " << tmp_file;
+                PLOG(ERROR) << "Faied to write tmp file: " << tmp_file;
                 return;
             }
             end = steady_clock::now();
@@ -284,7 +281,7 @@
         }
     } else {
         if (!WriteFully(fd, data, size)) {
-            PLOG_TO(SYSTEM, ERROR) << "Faied to write tmp file: " << tmp_file;
+            PLOG(ERROR) << "Faied to write tmp file: " << tmp_file;
             return;
         }
     }
@@ -343,22 +340,21 @@
     if (mConfig.event_time_check_usec &&
         clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &start_ts) < 0) {
         check_time = false;
-        PLOG_TO(SYSTEM, ERROR) << "clock_gettime() failed";
+        PLOG(ERROR) << "clock_gettime() failed";
     }
 
     event();
 
     if (mConfig.event_time_check_usec && check_time) {
         if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &end_ts) < 0) {
-            PLOG_TO(SYSTEM, ERROR) << "clock_gettime() failed";
+            PLOG(ERROR) << "clock_gettime() failed";
             return;
         }
         int64_t cost = (end_ts.tv_sec - start_ts.tv_sec) * SEC_TO_USEC +
                        (end_ts.tv_nsec - start_ts.tv_nsec) / USEC_TO_NSEC;
         if (cost > mConfig.event_time_check_usec) {
-            LOG_TO(SYSTEM, ERROR)
-                << "event loop spent " << cost << " usec, threshold "
-                << mConfig.event_time_check_usec << " usec";
+            LOG(ERROR) << "event loop spent " << cost << " usec, threshold "
+                       << mConfig.event_time_check_usec << " usec";
         }
     }
 }
diff --git a/storaged/storaged_diskstats.cpp b/storaged/storaged_diskstats.cpp
index 8b5001d..52bd4e0 100644
--- a/storaged/storaged_diskstats.cpp
+++ b/storaged/storaged_diskstats.cpp
@@ -41,8 +41,8 @@
     // skip if the input structure are all zeros
     if (perf == NULL || perf->is_zero()) return;
 
-    LOG_TO(SYSTEM, INFO) << "disk_perf " << type
-              << " rd: " << perf->read_perf << " kbps, " << perf->read_ios << " iops"
+    LOG(INFO) << "disk_perf " << type << " rd: " << perf->read_perf << " kbps, " << perf->read_ios
+              << " iops"
               << " wr: " << perf->write_perf << " kbps, " << perf->write_ios << " iops"
               << " q: " << perf->queue;
 }
@@ -71,7 +71,7 @@
     // when system is running.
     int ret = clock_gettime(CLOCK_MONOTONIC, ts);
     if (ret < 0) {
-        PLOG_TO(SYSTEM, ERROR) << "clock_gettime() failed";
+        PLOG(ERROR) << "clock_gettime() failed";
         return false;
     }
     return true;
@@ -93,7 +93,7 @@
 
     std::string buffer;
     if (!android::base::ReadFileToString(disk_stats_path, &buffer)) {
-        PLOG_TO(SYSTEM, ERROR) << disk_stats_path << ": ReadFileToString failed.";
+        PLOG(ERROR) << disk_stats_path << ": ReadFileToString failed.";
         return false;
     }
 
@@ -130,12 +130,12 @@
     bool success = false;
     auto ret = service->getDiskStats([&success, stats](auto result, const auto& halStats) {
         if (result == Result::NOT_SUPPORTED) {
-            LOG_TO(SYSTEM, DEBUG) << "getDiskStats is not supported on health HAL.";
+            LOG(DEBUG) << "getDiskStats is not supported on health HAL.";
             return;
         }
         if (result != Result::SUCCESS || halStats.size() == 0) {
-            LOG_TO(SYSTEM, ERROR) << "getDiskStats failed with result " << toString(result)
-                                  << " and size " << halStats.size();
+            LOG(ERROR) << "getDiskStats failed with result " << toString(result) << " and size "
+                       << halStats.size();
             return;
         }
 
@@ -144,7 +144,7 @@
     });
 
     if (!ret.isOk()) {
-        LOG_TO(SYSTEM, ERROR) << "getDiskStats failed with " << ret.description();
+        LOG(ERROR) << "getDiskStats failed with " << ret.description();
         return false;
     }
 
@@ -199,9 +199,9 @@
 void add_disk_stats(struct disk_stats* src, struct disk_stats* dst)
 {
     if (dst->end_time != 0 && dst->end_time != src->start_time) {
-        LOG_TO(SYSTEM, WARNING) << "Two dis-continuous periods of diskstats"
-            << " are added. dst end with " << dst->end_time
-            << ", src start with " << src->start_time;
+        LOG(WARNING) << "Two dis-continuous periods of diskstats"
+                     << " are added. dst end with " << dst->end_time << ", src start with "
+                     << src->start_time;
     }
 
     *dst += *src;
diff --git a/storaged/storaged_info.cpp b/storaged/storaged_info.cpp
index 6668cf3..bb21829 100644
--- a/storaged/storaged_info.cpp
+++ b/storaged/storaged_info.cpp
@@ -76,7 +76,7 @@
     if (!perf_history.has_day_start_sec() ||
         perf_history.daily_perf_size() > (int)daily_perf.size() ||
         perf_history.weekly_perf_size() > (int)weekly_perf.size()) {
-        LOG_TO(SYSTEM, ERROR) << "Invalid IOPerfHistory proto";
+        LOG(ERROR) << "Invalid IOPerfHistory proto";
         return;
     }
 
@@ -114,7 +114,7 @@
 {
     struct statvfs buf;
     if (statvfs(userdata_path.c_str(), &buf) != 0) {
-        PLOG_TO(SYSTEM, WARNING) << "Failed to get userdata info";
+        PLOG(WARNING) << "Failed to get userdata info";
         return;
     }
 
@@ -328,12 +328,12 @@
 void health_storage_info_t::report() {
     auto ret = mHealth->getStorageInfo([this](auto result, const auto& halInfos) {
         if (result == Result::NOT_SUPPORTED) {
-            LOG_TO(SYSTEM, DEBUG) << "getStorageInfo is not supported on health HAL.";
+            LOG(DEBUG) << "getStorageInfo is not supported on health HAL.";
             return;
         }
         if (result != Result::SUCCESS || halInfos.size() == 0) {
-            LOG_TO(SYSTEM, ERROR) << "getStorageInfo failed with result " << toString(result)
-                                  << " and size " << halInfos.size();
+            LOG(ERROR) << "getStorageInfo failed with result " << toString(result) << " and size "
+                       << halInfos.size();
             return;
         }
         set_values_from_hal_storage_info(halInfos[0]);
@@ -341,7 +341,7 @@
     });
 
     if (!ret.isOk()) {
-        LOG_TO(SYSTEM, ERROR) << "getStorageInfo failed with " << ret.description();
+        LOG(ERROR) << "getStorageInfo failed with " << ret.description();
     }
 }
 
diff --git a/storaged/storaged_uid_monitor.cpp b/storaged/storaged_uid_monitor.cpp
index 55380ba..f47bf72 100644
--- a/storaged/storaged_uid_monitor.cpp
+++ b/storaged/storaged_uid_monitor.cpp
@@ -71,8 +71,7 @@
         !ParseUint(fields[8],  &io[BACKGROUND].write_bytes) ||
         !ParseUint(fields[9],  &io[FOREGROUND].fsync) ||
         !ParseUint(fields[10], &io[BACKGROUND].fsync)) {
-        LOG_TO(SYSTEM, WARNING) << "Invalid uid I/O stats: \""
-                                << s << "\"";
+        LOG(WARNING) << "Invalid uid I/O stats: \"" << s << "\"";
         return false;
     }
     return true;
@@ -95,8 +94,7 @@
         !ParseUint(fields[size - 3], &io[BACKGROUND].write_bytes) ||
         !ParseUint(fields[size - 2], &io[FOREGROUND].fsync) ||
         !ParseUint(fields[size - 1], &io[BACKGROUND].fsync)) {
-        LOG_TO(SYSTEM, WARNING) << "Invalid task I/O stats: \""
-                                << s << "\"";
+        LOG(WARNING) << "Invalid task I/O stats: \"" << s << "\"";
         return false;
     }
     comm = Join(std::vector<std::string>(
@@ -123,13 +121,13 @@
 {
     sp<IServiceManager> sm = defaultServiceManager();
     if (sm == NULL) {
-        LOG_TO(SYSTEM, ERROR) << "defaultServiceManager failed";
+        LOG(ERROR) << "defaultServiceManager failed";
         return;
     }
 
     sp<IBinder> binder = sm->getService(String16("package_native"));
     if (binder == NULL) {
-        LOG_TO(SYSTEM, ERROR) << "getService package_native failed";
+        LOG(ERROR) << "getService package_native failed";
         return;
     }
 
@@ -137,8 +135,7 @@
     std::vector<std::string> names;
     binder::Status status = package_mgr->getNamesForUids(uids, &names);
     if (!status.isOk()) {
-        LOG_TO(SYSTEM, ERROR) << "package_native::getNamesForUids failed: "
-                              << status.exceptionMessage();
+        LOG(ERROR) << "package_native::getNamesForUids failed: " << status.exceptionMessage();
         return;
     }
 
@@ -158,7 +155,7 @@
     std::unordered_map<uint32_t, uid_info> uid_io_stats;
     std::string buffer;
     if (!ReadFileToString(UID_IO_STATS_PATH, &buffer)) {
-        PLOG_TO(SYSTEM, ERROR) << UID_IO_STATS_PATH << ": ReadFileToString failed";
+        PLOG(ERROR) << UID_IO_STATS_PATH << ": ReadFileToString failed";
         return uid_io_stats;
     }
 
diff --git a/trusty/Android.bp b/trusty/Android.bp
deleted file mode 100644
index 2fb2e19..0000000
--- a/trusty/Android.bp
+++ /dev/null
@@ -1,6 +0,0 @@
-subdirs = [
-    "gatekeeper",
-    "keymaster",
-    "libtrusty",
-    "storage/*",
-]
diff --git a/trusty/libtrusty/Android.bp b/trusty/libtrusty/Android.bp
index f6e9bee..8dba78d 100644
--- a/trusty/libtrusty/Android.bp
+++ b/trusty/libtrusty/Android.bp
@@ -12,10 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-subdirs = [
-    "tipc-test",
-]
-
 cc_library {
     name: "libtrusty",
     vendor: true,