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Commit d926aded authored by David Ng's avatar David Ng
Browse files

OverlayFS support for fstab 

Add overlayfs (lowerdir) mount entry support to fstab.

  overlay  <final dir>  overlay lowerdir=/1:/2

E.g.
  overlay /vendor overlay lowerdir=/odm/vnd_ovl1/1:/odm/vnd_ovl2

Test: Ensure mounting with fstab overlayfs entry
Change-Id: Ib025e203f8ac1836ab62dfa96fb14e8e108f82fb
parent 7b5e682d

fs_mgr/fs_mgr_fstab.cpp

+2 −0
Original line number Diff line number Diff line
@@ -298,6 +298,8 @@ void ParseFsMgrFlags(const std::string& flags, FstabEntry* entry) { 
            if (!ParseByteCount(arg, &entry->zram_backingdev_size)) {

                LWARNING << "Warning: zram_backingdev_size= flag malformed: " << arg;

            }

        } else if (StartsWith(flag, "lowerdir=")) {

            entry->lowerdir = arg;

        } else {

            LWARNING << "Warning: unknown flag: " << flag;

        }

fs_mgr/fs_mgr_overlayfs.cpp

+16 −0
Original line number Diff line number Diff line
@@ -92,6 +92,10 @@ bool fs_mgr_overlayfs_mount_all(Fstab*) { 
    return false;

}



bool fs_mgr_overlayfs_mount_fstab_entry(const std::string&, const std::string&) {

    return false;

}



std::vector<std::string> fs_mgr_overlayfs_required_devices(Fstab*) {

    return {};

}
@@ -1295,6 +1299,18 @@ static void TryMountScratch() { 
    }

}



bool fs_mgr_overlayfs_mount_fstab_entry(const std::string& lowers,

                                        const std::string& mount_point) {

    if (fs_mgr_overlayfs_invalid()) return false;



    std::string aux = "lowerdir=" + lowers + ",override_creds=off";

    auto rc = mount("overlay", mount_point.c_str(), "overlay", MS_RDONLY | MS_NOATIME, aux.c_str());



    if (rc == 0) return true;



    return false;

}



bool fs_mgr_overlayfs_mount_all(Fstab* fstab) {

    auto ret = false;

    if (fs_mgr_overlayfs_invalid()) return ret;

fs_mgr/include/fs_mgr_overlayfs.h

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
android::fs_mgr::Fstab fs_mgr_overlayfs_candidate_list(const android::fs_mgr::Fstab& fstab);



bool fs_mgr_overlayfs_mount_all(android::fs_mgr::Fstab* fstab);

bool fs_mgr_overlayfs_mount_fstab_entry (const std::string& lowers, const std::string& mount_point);

std::vector<std::string> fs_mgr_overlayfs_required_devices(android::fs_mgr::Fstab* fstab);

bool fs_mgr_overlayfs_setup(const char* backing = nullptr, const char* mount_point = nullptr,

                            bool* change = nullptr, bool force = true);

fs_mgr/include_fstab/fstab/fstab.h

+1 −0
Original line number Diff line number Diff line
@@ -55,6 +55,7 @@ struct FstabEntry { 
    std::string vbmeta_partition;

    uint64_t zram_backingdev_size = 0;

    std::string avb_keys;

    std::string lowerdir;



    struct FsMgrFlags {

        bool wait : 1;

init/first_stage_mount.cpp

+18 −0
Original line number Diff line number Diff line
@@ -331,6 +331,12 @@ bool FirstStageMount::InitRequiredDevices(std::set<std::string> devices) { 
    if (devices.empty()) {

        return true;

    }

    // excluding overlays

    for (auto iter = devices.begin(); iter != devices.end(); ) {

        if (*iter=="overlay")  iter = devices.erase(iter);

        else iter++;

    }



    return block_dev_init_.InitDevices(std::move(devices));

}
@@ -542,6 +548,11 @@ bool FirstStageMount::MountPartitions() { 
            continue;

        }



        if (current->fs_type == "overlay") {

            ++current;

            continue;

        }



        // Skip raw partition entries such as boot, dtbo, etc.

        // Having emmc fstab entries allows us to probe current->vbmeta_partition

        // in InitDevices() when they are AVB chained partitions.
@@ -591,6 +602,13 @@ bool FirstStageMount::MountPartitions() { 
    };

    MapScratchPartitionIfNeeded(&fstab_, init_devices);



    for (auto current = fstab_.begin(); current != fstab_.end(); ) {

        if (current->fs_type == "overlay") {

            fs_mgr_overlayfs_mount_fstab_entry(current->lowerdir, current->mount_point);

        }

        ++current;

    }



    fs_mgr_overlayfs_mount_all(&fstab_);



    return true;