1 # SPDX-License-Identifier: GPL-2.0-only 2 3 config 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 and the web pages at <https://erofs.docs.kernel.org> for more details. 25 26 If unsure, say N. 27 28 config 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 38 config 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 50 config 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 64 config 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 77 config 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 87 config 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 default LZ4 format, at the 96 expense of more CPU overhead. 97 98 If unsure, say N. 99 100 config EROFS_FS_ZIP_DEFLATE 101 bool "EROFS DEFLATE compressed data support" 102 depends on EROFS_FS_ZIP 103 select ZLIB_INFLATE 104 help 105 Saying Y here includes support for reading EROFS file systems 106 containing DEFLATE compressed data. It gives better compression 107 ratios than the default LZ4 format, while it costs more CPU 108 overhead. 109 110 DEFLATE support is an experimental feature for now and so most 111 file systems will be readable without selecting this option. 112 113 If unsure, say N. 114 115 config EROFS_FS_ZIP_ZSTD 116 bool "EROFS Zstandard compressed data support" 117 depends on EROFS_FS_ZIP 118 select ZSTD_DECOMPRESS 119 help 120 Saying Y here includes support for reading EROFS file systems 121 containing Zstandard compressed data. It gives better compression 122 ratios than the default LZ4 format, while it costs more CPU 123 overhead. 124 125 Zstandard support is an experimental feature for now and so most 126 file systems will be readable without selecting this option. 127 128 If unsure, say N. 129 130 config EROFS_FS_ONDEMAND 131 bool "EROFS fscache-based on-demand read support" 132 depends on EROFS_FS 133 select NETFS_SUPPORT 134 select FSCACHE 135 select CACHEFILES 136 select CACHEFILES_ONDEMAND 137 help 138 This permits EROFS to use fscache-backed data blobs with on-demand 139 read support. 140 141 If unsure, say N. 142 143 config EROFS_FS_PCPU_KTHREAD 144 bool "EROFS per-cpu decompression kthread workers" 145 depends on EROFS_FS_ZIP 146 help 147 Saying Y here enables per-CPU kthread workers pool to carry out 148 async decompression for low latencies on some architectures. 149 150 If unsure, say N. 151 152 config EROFS_FS_PCPU_KTHREAD_HIPRI 153 bool "EROFS high priority per-CPU kthread workers" 154 depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD 155 default y 156 help 157 This permits EROFS to configure per-CPU kthread workers to run 158 at higher priority. 159 160 If unsure, say N.
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