1# SPDX-License-Identifier: GPL-2.0-only 2 3config EROFS_FS 4 tristate "EROFS filesystem support" 5 depends on BLOCK 6 select FS_IOMAP 7 select LIBCRC32C 8 help 9 EROFS (Enhanced Read-Only File System) is a lightweight read-only 10 file system with modern designs (e.g. no buffer heads, inline 11 xattrs/data, chunk-based deduplication, multiple devices, etc.) for 12 scenarios which need high-performance read-only solutions, e.g. 13 smartphones with Android OS, LiveCDs and high-density hosts with 14 numerous containers; 15 16 It also provides fixed-sized output compression support in order to 17 improve storage density as well as keep relatively higher compression 18 ratios and implements in-place decompression to reuse the file page 19 for compressed data temporarily with proper strategies, which is 20 quite useful to ensure guaranteed end-to-end runtime decompression 21 performance under extremely memory pressure without extra cost. 22 23 See the documentation at <file:Documentation/filesystems/erofs.rst> 24 for more details. 25 26 If unsure, say N. 27 28config EROFS_FS_DEBUG 29 bool "EROFS debugging feature" 30 depends on EROFS_FS 31 help 32 Print debugging messages and enable more BUG_ONs which check 33 filesystem consistency and find potential issues aggressively, 34 which can be used for Android eng build, for example. 35 36 For daily use, say N. 37 38config EROFS_FS_XATTR 39 bool "EROFS extended attributes" 40 depends on EROFS_FS 41 default y 42 help 43 Extended attributes are name:value pairs associated with inodes by 44 the kernel or by users (see the attr(5) manual page, or visit 45 <http://acl.bestbits.at/> for details). 46 47 If unsure, say N. 48 49config EROFS_FS_POSIX_ACL 50 bool "EROFS Access Control Lists" 51 depends on EROFS_FS_XATTR 52 select FS_POSIX_ACL 53 default y 54 help 55 Posix Access Control Lists (ACLs) support permissions for users and 56 groups beyond the owner/group/world scheme. 57 58 To learn more about Access Control Lists, visit the POSIX ACLs for 59 Linux website <http://acl.bestbits.at/>. 60 61 If you don't know what Access Control Lists are, say N. 62 63config EROFS_FS_SECURITY 64 bool "EROFS Security Labels" 65 depends on EROFS_FS_XATTR 66 default y 67 help 68 Security labels provide an access control facility to support Linux 69 Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO 70 Linux. This option enables an extended attribute handler for file 71 security labels in the erofs filesystem, so that it requires enabling 72 the extended attribute support in advance. 73 74 If you are not using a security module, say N. 75 76config EROFS_FS_ZIP 77 bool "EROFS Data Compression Support" 78 depends on EROFS_FS 79 select LZ4_DECOMPRESS 80 default y 81 help 82 Enable fixed-sized output compression for EROFS. 83 84 If you don't want to enable compression feature, say N. 85 86config EROFS_FS_ZIP_LZMA 87 bool "EROFS LZMA compressed data support" 88 depends on EROFS_FS_ZIP 89 select XZ_DEC 90 select XZ_DEC_MICROLZMA 91 help 92 Saying Y here includes support for reading EROFS file systems 93 containing LZMA compressed data, specifically called microLZMA. it 94 gives better compression ratios than the LZ4 algorithm, at the 95 expense of more CPU overhead. 96 97 LZMA support is an experimental feature for now and so most file 98 systems will be readable without selecting this option. 99 100 If unsure, say N. 101 102config EROFS_FS_ONDEMAND 103 bool "EROFS fscache-based on-demand read support" 104 depends on CACHEFILES_ONDEMAND && (EROFS_FS=m && FSCACHE || EROFS_FS=y && FSCACHE=y) 105 default n 106 help 107 This permits EROFS to use fscache-backed data blobs with on-demand 108 read support. 109 110 If unsure, say N. 111 112config EROFS_FS_PCPU_KTHREAD 113 bool "EROFS per-cpu decompression kthread workers" 114 depends on EROFS_FS_ZIP 115 help 116 Saying Y here enables per-CPU kthread workers pool to carry out 117 async decompression for low latencies on some architectures. 118 119 If unsure, say N. 120 121config EROFS_FS_PCPU_KTHREAD_HIPRI 122 bool "EROFS high priority per-CPU kthread workers" 123 depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD 124 help 125 This permits EROFS to configure per-CPU kthread workers to run 126 at higher priority. 127 128 If unsure, say N. 129