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Commit c82ad4fd authored by Yi-Yo Chiang's avatar Yi-Yo Chiang
Browse files

fs_mgr_overlayfs: Remove backing image if failed to allocate scratch 

In CreateScratchOnData(), if backing image is allocated but failed to
map, then remove the backing image. Otherwise the unusable (unmappable)
image would waste a lot of space.

Bug: 255593675
Test: On device that don't support mapping gsid scratch,
  run `adb remount` and then check that gsid scratch is removed and
  scratch is allocated on super.
Test: TH run g3-app-compat-main
Change-Id: I0c01c2fd93a30ac0e46f4350c900403337530406
parent cb881e7c

fs_mgr/fs_mgr_overlayfs.cpp

+26 −16
Original line number Diff line number Diff line
@@ -462,6 +462,28 @@ bool fs_mgr_overlayfs_umount_scratch() { 
    return true;

}



OverlayfsTeardownResult TeardownDataScratch(IImageManager* images,

                                            const std::string& partition_name, bool was_mounted) {

    if (!images) {

        return OverlayfsTeardownResult::Error;

    }

    if (!images->DisableImage(partition_name)) {

        return OverlayfsTeardownResult::Error;

    }

    if (was_mounted) {

        // If overlayfs was mounted, don't bother trying to unmap since

        // it'll fail and create error spam.

        return OverlayfsTeardownResult::Busy;

    }

    if (!images->UnmapImageIfExists(partition_name)) {

        return OverlayfsTeardownResult::Busy;

    }

    if (!images->DeleteBackingImage(partition_name)) {

        return OverlayfsTeardownResult::Busy;

    }

    return OverlayfsTeardownResult::Ok;

}



OverlayfsTeardownResult fs_mgr_overlayfs_teardown_scratch(const std::string& overlay,

                                                          bool* change) {

    // umount and delete kScratchMountPoint storage if we have logical partitions
@@ -484,24 +506,9 @@ OverlayfsTeardownResult fs_mgr_overlayfs_teardown_scratch(const std::string& ove 


    auto images = IImageManager::Open("remount", 10s);

    if (images && images->BackingImageExists(partition_name)) {

        if (!images->DisableImage(partition_name)) {

            return OverlayfsTeardownResult::Error;

        }

        if (was_mounted) {

            // If overlayfs was mounted, don't bother trying to unmap since

            // it'll fail and create error spam.

            return OverlayfsTeardownResult::Busy;

        }

        if (!images->UnmapImageIfExists(partition_name)) {

            return OverlayfsTeardownResult::Busy;

        }

        if (!images->DeleteBackingImage(partition_name)) {

            return OverlayfsTeardownResult::Busy;

        }



        // No need to check super partition, if we knew we had a scratch device

        // in /data.

        return OverlayfsTeardownResult::Ok;

        return TeardownDataScratch(images.get(), partition_name, was_mounted);

    }



    auto slot_number = fs_mgr_overlayfs_slot_number();
@@ -1103,6 +1110,8 @@ static bool CreateScratchOnData(std::string* scratch_device, bool* partition_exi 
    }

    if (!images->MapImageDevice(partition_name, 10s, scratch_device)) {

        LERROR << "could not map scratch image";

        // If we cannot use this image, then remove it.

        TeardownDataScratch(images.get(), partition_name, false /* was_mounted */);

        return false;

    }

    return true;
@@ -1136,6 +1145,7 @@ bool fs_mgr_overlayfs_create_scratch(const Fstab& fstab, std::string* scratch_de 
        if (CreateScratchOnData(scratch_device, partition_exists)) {

            return true;

        }

        LOG(WARNING) << "Failed to allocate scratch on /data, fallback to use free space on super";

    }

    // If that fails, see if we can land on super.

    if (CanUseSuperPartition(fstab)) {