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Commit 4537a782 authored by Narayan Kamath's avatar Narayan Kamath Committed by Automerger Merge Worker
Browse files

Merge "Fix Deadlock Issue On AppFuseBridge" into rvc-dev am: a2754486 

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11894161

Change-Id: I48e7218c159cd1944c5aa77cfcbeda9969ccff0f
parents 7f7e19ed a2754486

services/core/java/com/android/server/storage/AppFuseBridge.java

+12 −0
Original line number Diff line number Diff line
@@ -56,6 +56,15 @@ public class AppFuseBridge implements Runnable { 


    public ParcelFileDescriptor addBridge(MountScope mountScope)

            throws FuseUnavailableMountException, NativeDaemonConnectorException {

        /*

        ** Dead Lock between Java lock (AppFuseBridge.java) and Native lock (FuseBridgeLoop.cc)

        **

        **  (Thread A) Got Java lock (addBrdige) -> Try to get Native lock (native_add_brdige)

        **  (Thread B)        Got Native lock (FuseBrdigeLoop.start) -> Try to get Java lock (onClosed)

        **

        ** Guarantee the lock order (native lock -> java lock) when adding Bridge.

        */

        native_lock();

        try {

            synchronized (this) {

                Preconditions.checkArgument(mScopes.indexOfKey(mountScope.mountId) < 0);
@@ -73,6 +82,7 @@ public class AppFuseBridge implements Runnable { 
                return result;

            }

        } finally {

            native_unlock();

            IoUtils.closeQuietly(mountScope);

        }

    }
@@ -159,4 +169,6 @@ public class AppFuseBridge implements Runnable { 
    private native void native_delete(long loop);

    private native void native_start_loop(long loop);

    private native int native_add_bridge(long loop, int mountId, int deviceId);

    private native void native_lock();

    private native void native_unlock();

}

services/core/jni/com_android_server_storage_AppFuseBridge.cpp

+18 −0
Original line number Diff line number Diff line
@@ -123,6 +123,14 @@ jint com_android_server_storage_AppFuseBridge_add_bridge( 
    return proxyFd[1].release();

}



void com_android_server_storage_AppFuseBridge_lock(JNIEnv* env, jobject self) {

    fuse::FuseBridgeLoop::Lock();

}



void com_android_server_storage_AppFuseBridge_unlock(JNIEnv* env, jobject self) {

    fuse::FuseBridgeLoop::Unlock();

}



const JNINativeMethod methods[] = {

    {

        "native_new",
@@ -143,6 +151,16 @@ const JNINativeMethod methods[] = { 
        "native_add_bridge",

        "(JII)I",

        reinterpret_cast<void*>(com_android_server_storage_AppFuseBridge_add_bridge)

    },

    {

        "native_lock",

        "()V",

        reinterpret_cast<void*>(com_android_server_storage_AppFuseBridge_lock)

    },

    {

        "native_unlock",

        "()V",

        reinterpret_cast<void*>(com_android_server_storage_AppFuseBridge_unlock)

    }

};