fix: fix crash caused by multi-threaded access

src/server/backend/eventsource_genl.cpp

@@ -195,28 +195,44 @@ void update_vfs_unnamed_device(const QSet<QByteArray> &news)
 
 void EventSource_GENL::updatePartitions()
 {
-    // 有mount/unmount事件，更新mount cache
-    MountCacher::instance()->updateMountPoints();
-
-    QList<MountPoint> mountList = MountCacher::instance()->getMountPointsByRoot("/");
-    if (mountList.isEmpty()) {
-        nWarning("getMountPointsByRoot(/) return empty");
+    /* Invokes updateMountPoints in the event loop of MountCacher to avoid multi-threaded access */
+    QMetaObject::invokeMethod(MountCacher::instance(), "updateMountPoints", Qt::QueuedConnection);
+
+    /*
+     * No use`MountCacher::instance()->getMountPointsByRoot("/")` to get mount list.
+     * This is to avoid multi-threaded access, and locks may cause dead locks.
+     */
+    QString file_mountinfo_path("/proc/self/mountinfo");
+    QFile file_mountinfo(file_mountinfo_path);
+    if (!file_mountinfo.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        QByteArray ba = file_mountinfo_path.toLatin1();
+        nWarning("open file failed: %s.", ba.data());
         return;
     }
+    QByteArray mount_info;
+    mount_info = file_mountinfo.readAll();
+    file_mountinfo.close();
 
     unsigned int major, minor;
+    char mp[256], root[256], type[256], *line = mount_info.data();
     QSet<QByteArray> dlnfs_devs;
     QByteArray ba;
     partitions.clear();
     nInfo("updatePartitions start.");
-    for(MountPoint info : mountList) {
-        unsigned long devno = info.deviceId;
-        major = major(devno);
-        minor = minor(devno);
-        partitions.insert(MKDEV(major, minor), info.mountTarget.toLocal8Bit());
-        if (info.mountType == "fuse.dlnfs") {
-            ba.setNum(minor);
-            dlnfs_devs.insert(ba);
+    while (sscanf(line, "%*d %*d %u:%u %250s %250s %*s %*s %*s %250s %*s %*s\n", &major, &minor, root, mp, type) == 5) {
+        line = strchr(line, '\n') + 1;
+
+        if (!major && strcmp(type, "fuse.dlnfs"))
+            continue;
+
+        if (!strcmp(root, "/")) {
+            partitions.insert(MKDEV(major, minor), QByteArray(mp));
+            nInfo("%u:%u, %s", major, minor, mp);
+            /* add monitoring for dlnfs device */
+            if (!major && !strcmp(type, "fuse.dlnfs")) {
+                ba.setNum(minor);
+                dlnfs_devs.insert(ba);
+            }
         }
     }
     update_vfs_unnamed_device(dlnfs_devs);

src/server/backend/lib/eventadaptor.cpp

@@ -10,13 +10,9 @@
 EventAdaptor::EventAdaptor(QObject *parent)
     : QObject(parent)
 {
-    action_buffers.clear();
-
-    connect(&handle_timer, &QTimer::timeout, this, &EventAdaptor::onHandleEvent, Qt::QueuedConnection);
-    // 每500ms 触发一次事件
+    connect(&handle_timer, &QTimer::timeout, this, &EventAdaptor::onHandleEvent);
     handle_timer.setInterval(500);
     handle_timer.start();
-    jobFinished = true;
 }
 
 EventAdaptor::~EventAdaptor()
@@ -26,55 +22,22 @@
 
 void EventAdaptor::pushEvent(QPair<QByteArray, QByteArray> &action)
 {
-    QMutexLocker locker(&mutex); // 加锁
+    QMutexLocker locker(&mutex);
     action_buffers.enqueue(action);
-    waitCondition.wakeAll();
 }
 
 bool EventAdaptor::popEvent(QPair<QByteArray, QByteArray> *action)
 {
+    QMutexLocker locker(&mutex);
     if (action_buffers.isEmpty()) {
         return false;
     }
-    QMutexLocker locker(&mutex); // 加锁
     *action = action_buffers.dequeue();
-    waitCondition.wakeAll();
     return true;
 }
 
 void EventAdaptor::onHandleEvent()
 {
-    // 单线程保证索引串行更新
-    if (!jobFinished) {
-        return;
-    }
-    QMetaObject::invokeMethod(this, "startWork", Qt::QueuedConnection);
-}
-
-
-bool EventAdaptor::ignoreAction(QByteArray &strArr, bool ignored)
-{
-    QString strPath = QString::fromLocal8Bit(strArr);
-    if (strPath.endsWith(".longname")) {
-        // 长文件名记录文件，直接忽略
-        return true;
-    }
-
-    //没有标记忽略前一条，则检查是否长文件目录
-    if (!ignored) {
-        // 向上找到一个当前文件的挂载点且匹配文件系统类型
-        if (MountCacher::instance()->pathMatchType(strPath, "fuse.dlnfs")) {
-            // 长文件目录，标记此条事件被忽略
-            return true;
-        }
-    }
-    return false;
-}
-
-void EventAdaptor::startWork()
-{
-    jobFinished = false;
-
     bool pop = false;
     QList<QPair<QByteArray, QByteArray>> tmpActions;
     bool ignored = false;
@@ -92,17 +55,28 @@
         }
     } while (pop);
 
-    // Start the worker thread
-    TaskThread* taskThread = new TaskThread(this);
-    connect(taskThread, &TaskThread::workFinished, this, &EventAdaptor::handleTaskFinish);
-    connect(taskThread, &QThread::finished, taskThread, &QThread::deleteLater);
-    taskThread->setData(onHandler, tmpActions);
-    taskThread->start();
+    if (!tmpActions.isEmpty()) {
+        onHandler(tmpActions);
+    }
 }
 
-void EventAdaptor::handleTaskFinish()
+bool EventAdaptor::ignoreAction(QByteArray &strArr, bool ignored)
 {
-    jobFinished = true;
+    QString strPath = QString::fromLocal8Bit(strArr);
+    if (strPath.endsWith(".longname")) {
+        // 长文件名记录文件，直接忽略
+        return true;
+    }
+
+    //没有标记忽略前一条，则检查是否长文件目录
+    if (!ignored) {
+        // 向上找到一个当前文件的挂载点且匹配文件系统类型
+        if (MountCacher::instance()->pathMatchType(strPath, "fuse.dlnfs")) {
+            // 长文件目录，标记此条事件被忽略
+            return true;
+        }
+    }
+    return false;
 }
 
 DAS_END_NAMESPACE

src/server/backend/lib/eventadaptor.h

@@ -10,9 +10,7 @@
 #include <QObject>
 #include <QTimer>
 #include <QMutex>
-#include <QWaitCondition>
 #include <QQueue>
-#include <QThread>
 
 DAS_BEGIN_NAMESPACE
 
@@ -31,10 +29,6 @@ class EventAdaptor : public QObject
     void pushEvent(QPair<QByteArray, QByteArray> &action);
     bool popEvent(QPair<QByteArray, QByteArray> *action);
 
-public slots:
-    void startWork();
-    void handleTaskFinish();
-
 public:
     OnHandleEvent onHandler;
 
@@ -46,45 +40,8 @@ private slots:
 
 private:
     QMutex mutex;
-    QWaitCondition waitCondition;
     QQueue<QPair<QByteArray, QByteArray>> action_buffers;
     QTimer handle_timer;
-    // 用于事件更新，串行进行
-    bool jobFinished = true;
-};
-
-class TaskThread : public QThread
-{
-    Q_OBJECT
-public:
-    explicit TaskThread(QObject *parent = nullptr) : QThread(parent) {}
-    ~TaskThread() override {
-        handleFunc = nullptr;
-        actionList.clear();
-        deleteLater();
-    }
-    void run() override
-    {
-        // 后台回调处理事件，更新索引
-        if (handleFunc)
-            handleFunc(actionList);
-
-        emit workFinished();
-    }
-
-public slots:
-    void setData(OnHandleEvent callbackFunc, QList<QPair<QByteArray, QByteArray>> &actions)
-    {
-        handleFunc = callbackFunc;
-        actionList = actions;
-    }
-
-signals:
-    void workFinished();
-
-private:
-    OnHandleEvent handleFunc = nullptr;
-    QList<QPair<QByteArray, QByteArray>> actionList;
 };
 
 DAS_END_NAMESPACE

src/server/backend/lib/lftdisktool.cpp

@@ -19,19 +19,17 @@
 Q_GLOBAL_STATIC(DDiskManager, _global_diskManager)
 Q_LOGGING_CATEGORY(logN, "anything.normal.disktool", DEFAULT_MSG_TYPE)
 
-static deepin_anything_server::MountCacher *s_mountCacher = deepin_anything_server::MountCacher::instance();
-
 QByteArray pathToSerialUri(const QString &path)
 {
     // 避免使用QDir/QStorageInfo, 如果IO被阻塞（U盘正在被扫描或网络盘断网），则导致卡顿或假死
     // 向上找到路径的真实挂载点
-    const QString mountPoint = s_mountCacher->findMountPointByPath(path);
+    const QString mountPoint = deepin_anything_server::MountCacher::instance()->findMountPointByPath(path);
     if (mountPoint.isEmpty()) {
         nWarning() << "pathToSerialUri findMountPointByPath NULL for:" << path;
         return QByteArray();
     }
 
-    const QString device = s_mountCacher->getDeviceByPoint(mountPoint);
+    const QString device = deepin_anything_server::MountCacher::instance()->getDeviceByPoint(mountPoint);
     if (!device.startsWith("/dev/") || device.startsWith("/dev/loop") || device.compare("/dev/fuse") == 0) {
         nWarning() << "ingore device:" << device;
         return QByteArray();
@@ -51,7 +49,7 @@
     if (block_id.isEmpty())
         return QByteArray();
 
-    const auto mount_info_map = s_mountCacher->getRootsByPoints({mountPoint.toLocal8Bit()});
+    const auto mount_info_map = deepin_anything_server::MountCacher::instance()->getRootsByPoints({mountPoint.toLocal8Bit()});
     QByteArray mount_root_path;
 
     // 只获取一个，返回就取第一个值
@@ -94,7 +92,7 @@
 
         if (_block_id == block_id) {
             const QByteArrayList &mount_points = block_obj->mountPoints();
-            const auto mount_point_infos = s_mountCacher->getRootsByPoints(mount_points);
+            const auto mount_point_infos = deepin_anything_server::MountCacher::instance()->getRootsByPoints(mount_points);
             QByteArrayList pathList;
 
             for (QByteArray mount_point : mount_points) {

src/server/backend/lib/mountcacher.cpp

@@ -14,6 +14,9 @@
 
 DAS_BEGIN_NAMESPACE
 
+class _MountCacher : public MountCacher {};
+Q_GLOBAL_STATIC(_MountCacher, mountCacherGlobal)
+
 /* error callback */
 static int parser_errcb(libmnt_table *tb, const char *filename, int line)
 {
@@ -34,14 +37,13 @@
 
 MountCacher *MountCacher::instance()
 {
-    static MountCacher ins;
-    return &ins;
+    return mountCacherGlobal;
 }
 
 MountCacher::MountCacher(QObject *parent)
     : QObject(parent)
 {
-    mountPointList.clear();
+    updateMountPoints();
 }
 
 MountCacher::~MountCacher()
@@ -103,10 +105,6 @@
 {
     QString result;
     QString result_path = path;
-    if (hardreal) {
-        // 如果跳过虚拟，查找真实设备的挂载点，须检查挂载信息是否已获取
-        checkCurrentMounts();
-    }
 
     Q_FOREVER {
         char *checkpath = QFile::encodeName(result_path).data();
@@ -158,10 +156,9 @@
 {
     bool result= false;
     QString point = findMountPointByPath(path);
-    checkCurrentMounts();
 
     for (MountPoint info: mountPointList) {
         if (point == info.mountTarget && type == info.mountType) {
             result = true;
             break;
         }
@@ -170,10 +167,9 @@
 }
 
 // 块设备存在多个挂载点，获取他们的根
 QMap<QByteArray, QString> MountCacher::getRootsByPoints(const QByteArrayList &pointList)
 {
     QMap<QByteArray, QString> map;
-    checkCurrentMounts();
 
     for (const QByteArray &point : pointList) {
         const QString target = QString(point);
@@ -188,13 +184,12 @@
 }
 
 // 获取挂载点的设备（source）, 必须传入真实挂载点
 QString MountCacher::getDeviceByPoint(const QString &point)
 {
     QString device;
-    checkCurrentMounts();
 
     for (MountPoint info: mountPointList) {
         if (point == info.mountTarget) {
             device = QString(info.realDevice);
             break;
         }
@@ -203,9 +198,8 @@
 }
 
 // 获取所有根为指定的挂载点, 不指定则返回全部挂载点信息
 QList<MountPoint> MountCacher::getMountPointsByRoot(const QString &root)
 {
-    checkCurrentMounts();
     if (root == nullptr || !root.startsWith('/')) {
         return mountPointList;
     }
@@ -219,14 +213,6 @@
     return list;
 }
 
-void MountCacher::checkCurrentMounts()
-{
-    if (mountPointList.isEmpty()) {
-        nWarning() << "mountPointList is empty, updat it first.";
-        updateMountPoints();
-    }
-}
-
 QDebug operator<<(QDebug debug, const MountPoint &mp)
 {
     QDebugStateSaver saver(debug);

src/server/backend/lib/mountcacher.h

@@ -29,8 +29,8 @@ class MountCacher : public QObject
     Q_DISABLE_COPY(MountCacher)
 
 public:
+    ~MountCacher();
     static MountCacher *instance();
-    bool updateMountPoints();
     QString findMountPointByPath(const QString &path, bool hardreal = false);
     bool pathMatchType(const QString &path, const QString &type);
 
@@ -43,11 +43,12 @@ class MountCacher : public QObject
     // 获取所有根为指定的挂载点, 不指定则返回全部挂载点信息
     QList<MountPoint> getMountPointsByRoot(const QString &root = nullptr);
 
-private:
+public slots:
+    bool updateMountPoints();
+
+protected:
     explicit MountCacher(QObject *parent = nullptr);
-    ~MountCacher();
 
-    void checkCurrentMounts();
 private:
     QList<MountPoint> mountPointList;
 };