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 select XXHASH 42 default y 43 help 44 Extended attributes are name:value pairs associated with inodes by 45 the kernel or by users (see the attr(5) manual page, or visit 46 <http://acl.bestbits.at/> for details). 47 48 If unsure, say N. 49 50config EROFS_FS_POSIX_ACL 51 bool "EROFS Access Control Lists" 52 depends on EROFS_FS_XATTR 53 select FS_POSIX_ACL 54 default y 55 help 56 Posix Access Control Lists (ACLs) support permissions for users and 57 groups beyond the owner/group/world scheme. 58 59 To learn more about Access Control Lists, visit the POSIX ACLs for 60 Linux website <http://acl.bestbits.at/>. 61 62 If you don't know what Access Control Lists are, say N. 63 64config EROFS_FS_SECURITY 65 bool "EROFS Security Labels" 66 depends on EROFS_FS_XATTR 67 default y 68 help 69 Security labels provide an access control facility to support Linux 70 Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO 71 Linux. This option enables an extended attribute handler for file 72 security labels in the erofs filesystem, so that it requires enabling 73 the extended attribute support in advance. 74 75 If you are not using a security module, say N. 76 77config EROFS_FS_ZIP 78 bool "EROFS Data Compression Support" 79 depends on EROFS_FS 80 select LZ4_DECOMPRESS 81 default y 82 help 83 Enable fixed-sized output compression for EROFS. 84 85 If you don't want to enable compression feature, say N. 86 87config EROFS_FS_ZIP_LZMA 88 bool "EROFS LZMA compressed data support" 89 depends on EROFS_FS_ZIP 90 select XZ_DEC 91 select XZ_DEC_MICROLZMA 92 help 93 Saying Y here includes support for reading EROFS file systems 94 containing LZMA compressed data, specifically called microLZMA. it 95 gives better compression ratios than the LZ4 algorithm, at the 96 expense of more CPU overhead. 97 98 LZMA support is an experimental feature for now and so most file 99 systems will be readable without selecting this option. 100 101 If unsure, say N. 102 103config EROFS_FS_ZIP_DEFLATE 104 bool "EROFS DEFLATE compressed data support" 105 depends on EROFS_FS_ZIP 106 select ZLIB_INFLATE 107 help 108 Saying Y here includes support for reading EROFS file systems 109 containing DEFLATE compressed data. It gives better compression 110 ratios than the default LZ4 format, while it costs more CPU 111 overhead. 112 113 DEFLATE support is an experimental feature for now and so most 114 file systems will be readable without selecting this option. 115 116 If unsure, say N. 117 118config EROFS_FS_ONDEMAND 119 bool "EROFS fscache-based on-demand read support" 120 depends on CACHEFILES_ONDEMAND && (EROFS_FS=m && FSCACHE || EROFS_FS=y && FSCACHE=y) 121 default n 122 help 123 This permits EROFS to use fscache-backed data blobs with on-demand 124 read support. 125 126 If unsure, say N. 127 128config EROFS_FS_PCPU_KTHREAD 129 bool "EROFS per-cpu decompression kthread workers" 130 depends on EROFS_FS_ZIP 131 help 132 Saying Y here enables per-CPU kthread workers pool to carry out 133 async decompression for low latencies on some architectures. 134 135 If unsure, say N. 136 137config EROFS_FS_PCPU_KTHREAD_HIPRI 138 bool "EROFS high priority per-CPU kthread workers" 139 depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD 140 default y 141 help 142 This permits EROFS to configure per-CPU kthread workers to run 143 at higher priority. 144 145 If unsure, say N. 146