Merge fuse unmount paths to reduce fuse unmount total time
Previously, we were waiting unnecessarily for long times trying to unmount
different fuse paths with no luck at the end. Made sure that we merge
these unmount flows so that we don't sleep separately for each unmount.
Additionally, added polling logic to not sleep the whole duration
without trying to unmount. Further more, made sure that we try to kill
apps using storage/emulated when unmounting fuse paths.
More details about the change can be found here go/mount-performance-improvement
Test: atest AdoptableHostTest, atest StorageManagerTest
Bug: 318335297
Bug: 402367661
Bug: 369519866
Flag: android.vold.flags.enhance_fuse_unmount
Change-Id: Id8af00fd1bff1de4078e4acd148a918738b4cea6
diff --git a/Utils.cpp b/Utils.cpp
index c4070d1..9ad828c 100644
--- a/Utils.cpp
+++ b/Utils.cpp
@@ -1724,6 +1724,139 @@
return result;
}
+/* returns list of non unmounted paths */
+std::vector<std::string> UnmountFusePaths(const std::vector<std::string>& paths_to_unmount) {
+ std::vector<std::string> non_unmounted_paths;
+ for (const auto& path : paths_to_unmount) {
+ LOG(INFO) << "Unmounting fuse path " << path;
+ const char* cpath = path.c_str();
+ if (!umount2(cpath, UMOUNT_NOFOLLOW) || errno == EINVAL || errno == ENOENT) {
+ rmdir(cpath);
+ continue;
+ }
+ non_unmounted_paths.push_back(path);
+ }
+ return non_unmounted_paths;
+}
+
+/* returns list of non unmounted paths */
+std::vector<std::string> UnmountFusePathsWithSleepAndPolling(
+ const std::vector<std::string>& paths_to_unmount) {
+ std::vector<std::string> non_unmounted_paths = paths_to_unmount;
+
+ int count = 10;
+ while (count-- > 0) {
+ usleep(500 * 1000);
+ non_unmounted_paths = UnmountFusePaths(non_unmounted_paths);
+ if (non_unmounted_paths.empty()) {
+ return non_unmounted_paths;
+ }
+ }
+ return non_unmounted_paths;
+}
+
+/* returns list of non unmounted paths */
+std::vector<std::string> KillProcessesWithFuseOpenFilesAndUnmount(
+ const std::vector<std::string>& paths_to_unmount, const std::string& absolute_upper_path,
+ int signal, bool kill_fuse_daemon, bool force_sleep_if_no_processes_killed) {
+
+ // In addition to killing apps using paths to unmount, we need to kill aps using
+ // the upper path (e.g storage/emulated) As they would prevent unmounting fuse
+ std::vector<std::string> paths_to_kill(paths_to_unmount);
+ paths_to_kill.push_back(absolute_upper_path);
+
+ int total_killed_pids = KillProcessesWithOpenFiles(paths_to_kill, signal, kill_fuse_daemon);
+
+ if (sSleepOnUnmount && (force_sleep_if_no_processes_killed || total_killed_pids)) {
+ return UnmountFusePathsWithSleepAndPolling(paths_to_unmount);
+ }
+ return UnmountFusePaths(paths_to_unmount);
+}
+
+status_t UnmountUserFuseEnhanced(userid_t user_id, const std::string& absolute_lower_path,
+ const std::string& relative_upper_path,
+ const std::string& absolute_upper_path,
+ const std::vector<std::string>& bind_mount_paths) {
+ std::vector<std::string> paths_to_unmount(bind_mount_paths);
+
+ std::string fuse_path(StringPrintf("/mnt/user/%d/%s", user_id, relative_upper_path.c_str()));
+ paths_to_unmount.push_back(fuse_path);
+
+ std::string pass_through_path(
+ StringPrintf("/mnt/pass_through/%d/%s", user_id, relative_upper_path.c_str()));
+ paths_to_unmount.push_back(pass_through_path);
+
+ auto start_time = std::chrono::steady_clock::now();
+ LOG(INFO) << "Unmounting fuse paths";
+
+ // Try unmounting without killing any processes
+ paths_to_unmount = UnmountFusePaths(paths_to_unmount);
+ if (paths_to_unmount.empty()) {
+ return android::OK;
+ }
+
+ // Kill processes except for FuseDaemon holding references to fuse paths with SIGINT
+ // And try to unmount afterwards with sleep and polling mechanism
+ paths_to_unmount = KillProcessesWithFuseOpenFilesAndUnmount(
+ paths_to_unmount, absolute_upper_path, SIGINT, /*kill_fuse_daemon*/ false,
+ /*force_sleep_if_no_processes_killed*/false);
+ if (paths_to_unmount.empty()) {
+ return android::OK;
+ }
+
+ // Kill processes except for FuseDaemon holding references to fuse paths with SIGTERM
+ // And try to unmount afterwards with sleep and polling mechanism
+ paths_to_unmount = KillProcessesWithFuseOpenFilesAndUnmount(
+ paths_to_unmount, absolute_upper_path, SIGTERM, /*kill_fuse_daemon*/ false,
+ /*force_sleep_if_no_processes_killed*/false);
+
+ if (paths_to_unmount.empty()) {
+ return android::OK;
+ }
+
+ auto now = std::chrono::steady_clock::now();
+ auto time_elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(now - start_time);
+ bool force_sleep_if_no_process_killed = time_elapsed < std::chrono::milliseconds(5000);
+ // Kill processes except for FuseDaemon holding references to fuse paths with SIGKILL
+ // And try to unmount afterwards with sleep and polling mechanism
+ // intentionally force sleep if sSleepOnUnmount isn't set to false
+ // and if we haven't slept in previous retries so that we give MediaProvider time
+ // to release FDs prior to try killing it in the next step
+ paths_to_unmount = KillProcessesWithFuseOpenFilesAndUnmount(
+ paths_to_unmount, absolute_upper_path, SIGKILL, /*kill_fuse_daemon*/ false,
+ force_sleep_if_no_process_killed);
+
+ if (paths_to_unmount.empty()) {
+ return android::OK;
+ }
+
+ // Kill processes including FuseDaemon holding references to fuse paths with SIGKILL
+ // And try to unmount afterwards with sleep and polling mechanism
+ paths_to_unmount = KillProcessesWithFuseOpenFilesAndUnmount(
+ paths_to_unmount, absolute_upper_path, SIGKILL, /*kill_fuse_daemon*/ true,
+ /*force_sleep_if_no_processes_killed*/false);
+ if (paths_to_unmount.empty()) {
+ return android::OK;
+ }
+
+ // If we reached here, then it means that previous kill and unmount retries didn't succeed
+ // Try to unmount with MNT_DETACH so we try lazily unmount
+ android::status_t result = android::OK;
+ for (const auto& path : paths_to_unmount) {
+ LOG(ERROR) << "Failed to unmount. Trying MNT_DETACH " << path;
+ const char* cpath = path.c_str();
+ if (!umount2(cpath, UMOUNT_NOFOLLOW | MNT_DETACH) || errno == EINVAL || errno == ENOENT) {
+ rmdir(cpath);
+ continue;
+ }
+ PLOG(ERROR) << "Failed to unmount with MNT_DETACH " << path;
+ if (path == fuse_path) {
+ result = -errno;
+ }
+ }
+ return result;
+}
+
status_t PrepareAndroidDirs(const std::string& volumeRoot) {
std::string androidDir = volumeRoot + kAndroidDir;
std::string androidDataDir = volumeRoot + kAppDataDir;