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Commit d4de636c authored by Zim's avatar Zim
Browse files

Use lower filesystem path when destroying user data with FUSE 

With the FUSE prop enabled, when a user is removed, the upper
filesystem path would have been unmounted before installd gets to
delete its content and an empty tmpfs will be deleted instead, leaving
the content on the lower filesystem.

Now, we always use the lower filesystem when deleting the users dir
and cache. This is fine on devices without sdcardfs but on devices
running sdcardfs, we should use the sdcardfs path instead to avoid
VFS inode cache inconsistencies

Test: adb shell pm create-user && adb shell am start-user 10 && adb
shell pm delete-user. Verify that /data/media/10 is deleted
Bug: 135341433
Change-Id: Iaeb9ea3db373d358251644a95b3390cfa2b8f24a
parent 15d82e51

cmds/installd/InstalldNativeService.cpp

+13 −0
Original line number Diff line number Diff line
@@ -2799,6 +2799,8 @@ binder::Status InstalldNativeService::invalidateMounts() { 
        std::getline(in, ignored);



        if (android::base::GetBoolProperty(kFuseProp, false)) {

            // TODO(b/146139106): Use sdcardfs mounts on devices running sdcardfs so we don't bypass

            // it's VFS cache

            if (target.compare(0, 17, "/mnt/pass_through") == 0) {

                LOG(DEBUG) << "Found storage mount " << source << " at " << target;

                mStorageMounts[source] = target;
@@ -2820,6 +2822,17 @@ std::string InstalldNativeService::findDataMediaPath( 
    std::lock_guard<std::recursive_mutex> lock(mMountsLock);

    const char* uuid_ = uuid ? uuid->c_str() : nullptr;

    auto path = StringPrintf("%s/media", create_data_path(uuid_).c_str());

    if (android::base::GetBoolProperty(kFuseProp, false)) {

        // TODO(b/146139106): This is only safe on devices not running sdcardfs where there is no

        // risk of bypassing the sdcardfs VFS cache



        // Always use the lower filesystem path on FUSE enabled devices not running sdcardfs

        // The upper filesystem path, /mnt/pass_through/<userid>/<vol>/ which was a bind mount

        // to the lower filesytem may have been unmounted already when a user is

        // removed and the path will now be pointing to a tmpfs without content

        return StringPrintf("%s/%u", path.c_str(), userid);

    }



    auto resolved = mStorageMounts[path];

    if (resolved.empty()) {

        LOG(WARNING) << "Failed to find storage mount for " << path;