# SPDX-License-Identifier: GPL-2.0 config EROFS_FS tristate "EROFS filesystem support" depends on BLOCK help EROFS(Enhanced Read-Only File System) is a lightweight read-only file system with modern designs (eg. page-sized blocks, inline xattrs/data, etc.) for scenarios which need high-performance read-only requirements, eg. firmwares in mobile phone or LIVECDs. It also provides VLE compression support, focusing on random read improvements, keeping relatively lower compression ratios, which is useful for high-performance devices with limited memory and ROM space. If unsure, say N. config EROFS_FS_DEBUG bool "EROFS debugging feature" depends on EROFS_FS help Print EROFS debugging messages and enable more BUG_ONs which check the filesystem consistency aggressively. For daily use, say N. config EROFS_FS_XATTR bool "EROFS extended attributes" depends on EROFS_FS default y help Extended attributes are name:value pairs associated with inodes by the kernel or by users (see the attr(5) manual page, or visit for details). If unsure, say N. config EROFS_FS_POSIX_ACL bool "EROFS Access Control Lists" depends on EROFS_FS_XATTR select FS_POSIX_ACL default y help Posix Access Control Lists (ACLs) support permissions for users and groups beyond the owner/group/world scheme. To learn more about Access Control Lists, visit the POSIX ACLs for Linux website . If you don't know what Access Control Lists are, say N. config EROFS_FS_SECURITY bool "EROFS Security Labels" depends on EROFS_FS_XATTR help Security labels provide an access control facility to support Linux Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO Linux. This option enables an extended attribute handler for file security labels in the erofs filesystem, so that it requires enabling the extended attribute support in advance. If you are not using a security module, say N. config EROFS_FS_USE_VM_MAP_RAM bool "EROFS VM_MAP_RAM Support" depends on EROFS_FS help use vm_map_ram/vm_unmap_ram instead of vmap/vunmap. If you don't know what these are, say N. config EROFS_FAULT_INJECTION bool "EROFS fault injection facility" depends on EROFS_FS help Test EROFS to inject faults such as ENOMEM, EIO, and so on. If unsure, say N. config EROFS_FS_IO_MAX_RETRIES int "EROFS IO Maximum Retries" depends on EROFS_FS default "5" help Maximum retry count of IO Errors. If unsure, leave the default value (5 retries, 6 IOs at most). config EROFS_FS_ZIP bool "EROFS Data Compresssion Support" depends on EROFS_FS help Currently we support VLE Compression only. Play at your own risk. If you don't want to use compression feature, say N. config EROFS_FS_CLUSTER_PAGE_LIMIT int "EROFS Cluster Pages Hard Limit" depends on EROFS_FS_ZIP range 1 256 default "1" help Indicates VLE compressed pages hard limit of a compressed cluster. For example, if files of a image are compressed into 8k-unit, the hard limit should not be less than 2. Otherwise, the image cannot be mounted correctly on this kernel. choice prompt "EROFS VLE Data Decompression mode" depends on EROFS_FS_ZIP default EROFS_FS_ZIP_CACHE_BIPOLAR help EROFS supports three options for VLE decompression. "In-place Decompression Only" consumes the minimum memory with lowest random read. "Bipolar Cached Decompression" consumes the maximum memory with highest random read. If unsure, select "Bipolar Cached Decompression" config EROFS_FS_ZIP_NO_CACHE bool "In-place Decompression Only" help Read compressed data into page cache and do in-place decompression directly. config EROFS_FS_ZIP_CACHE_UNIPOLAR bool "Unipolar Cached Decompression" help For each request, it caches the last compressed page for further reading. It still decompresses in place for the rest compressed pages. config EROFS_FS_ZIP_CACHE_BIPOLAR bool "Bipolar Cached Decompression" help For each request, it caches the both end compressed pages for further reading. It still decompresses in place for the rest compressed pages. Recommended for performance priority. endchoice config EROFS_FS_HUAWEI_EXTENSION bool "EROFS HUAWEI Extension" depends on EROFS_FS && EROFS_FS_ZIP help Targeted optimizations for HUAWEI Mobile phone. If unsure, say N.