Merge "fs_mgr: overlayfs: dig harder for /dev/root equivalent" am: 2edc7a5128 (3c911bea) · Commits · e / os / android_system_core

fs_mgr/fs_mgr_overlayfs.cpp

+32 −9

Original line number	Diff line number	Diff line
		@@ -150,6 +150,31 @@ bool fs_mgr_filesystem_has_space(const std::string& mount_point) {
		return (vst.f_bfree >= (vst.f_blocks * kPercentThreshold / 100));
		}

		const auto kPhysicalDevice = "/dev/block/by-name/"s;

		bool fs_mgr_update_blk_device(FstabEntry* entry) {
		if (entry->fs_mgr_flags.logical) {
		fs_mgr_update_logical_partition(entry);
		}
		if (fs_mgr_access(entry->blk_device)) {
		return true;
		}
		if (entry->blk_device != "/dev/root") {
		return false;
		}

		// special case for system-as-root (taimen and others)
		auto blk_device = kPhysicalDevice + "system";
		if (!fs_mgr_access(blk_device)) {
		blk_device += fs_mgr_get_slot_suffix();
		if (!fs_mgr_access(blk_device)) {
		return false;
		}
		}
		entry->blk_device = blk_device;
		return true;
		}

		bool fs_mgr_overlayfs_enabled(FstabEntry* entry) {
		// readonly filesystem, can not be mount -o remount,rw
		// for squashfs, erofs or if free space is (near) zero making such a remount
		@@ -157,19 +182,19 @@ bool fs_mgr_overlayfs_enabled(FstabEntry* entry) {
		if (!fs_mgr_filesystem_has_space(entry->mount_point)) {
		return true;
		}
		if (entry->fs_mgr_flags.logical) {
		fs_mgr_update_logical_partition(entry);

		// blk_device needs to be setup so we can check superblock.
		// If we fail here, because during init first stage and have doubts.
		if (!fs_mgr_update_blk_device(entry)) {
		return true;
		}

		// check if ext4 de-dupe
		auto save_errno = errno;
		errno = 0;
		auto has_shared_blocks = fs_mgr_has_shared_blocks(entry->mount_point, entry->blk_device);
		if (!has_shared_blocks && (entry->mount_point == "/system")) {
		has_shared_blocks = fs_mgr_has_shared_blocks("/", entry->blk_device);
		}
		// special case for first stage init for system as root (taimen)
		if (!has_shared_blocks && (errno == ENOENT) && (entry->blk_device == "/dev/root")) {
		has_shared_blocks = true;
		}
		errno = save_errno;
		return has_shared_blocks;
		}
		@@ -388,8 +413,6 @@ uint32_t fs_mgr_overlayfs_slot_number() {
		return SlotNumberForSlotSuffix(fs_mgr_get_slot_suffix());
		}

		const auto kPhysicalDevice = "/dev/block/by-name/"s;

		std::string fs_mgr_overlayfs_super_device(uint32_t slot_number) {
		return kPhysicalDevice + fs_mgr_get_super_partition_name(slot_number);
		}