1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 2
3 config EROFS_FS 3 config EROFS_FS
4 tristate "EROFS filesystem support" 4 tristate "EROFS filesystem support"
5 depends on BLOCK 5 depends on BLOCK
6 select FS_IOMAP 6 select FS_IOMAP
7 select LIBCRC32C 7 select LIBCRC32C
8 help 8 help
9 EROFS (Enhanced Read-Only File Syste 9 EROFS (Enhanced Read-Only File System) is a lightweight read-only
10 file system with modern designs (e.g 10 file system with modern designs (e.g. no buffer heads, inline
11 xattrs/data, chunk-based deduplicati 11 xattrs/data, chunk-based deduplication, multiple devices, etc.) for
12 scenarios which need high-performanc 12 scenarios which need high-performance read-only solutions, e.g.
13 smartphones with Android OS, LiveCDs 13 smartphones with Android OS, LiveCDs and high-density hosts with
14 numerous containers; 14 numerous containers;
15 15
16 It also provides fixed-sized output 16 It also provides fixed-sized output compression support in order to
17 improve storage density as well as k 17 improve storage density as well as keep relatively higher compression
18 ratios and implements in-place decom 18 ratios and implements in-place decompression to reuse the file page
19 for compressed data temporarily with 19 for compressed data temporarily with proper strategies, which is
20 quite useful to ensure guaranteed en 20 quite useful to ensure guaranteed end-to-end runtime decompression
21 performance under extremely memory p 21 performance under extremely memory pressure without extra cost.
22 22
23 See the documentation at <file:Docum 23 See the documentation at <file:Documentation/filesystems/erofs.rst>
24 and the web pages at <https://erofs. 24 and the web pages at <https://erofs.docs.kernel.org> for more details.
25 25
26 If unsure, say N. 26 If unsure, say N.
27 27
28 config EROFS_FS_DEBUG 28 config EROFS_FS_DEBUG
29 bool "EROFS debugging feature" 29 bool "EROFS debugging feature"
30 depends on EROFS_FS 30 depends on EROFS_FS
31 help 31 help
32 Print debugging messages and enable 32 Print debugging messages and enable more BUG_ONs which check
33 filesystem consistency and find pote 33 filesystem consistency and find potential issues aggressively,
34 which can be used for Android eng bu 34 which can be used for Android eng build, for example.
35 35
36 For daily use, say N. 36 For daily use, say N.
37 37
38 config EROFS_FS_XATTR 38 config EROFS_FS_XATTR
39 bool "EROFS extended attributes" 39 bool "EROFS extended attributes"
40 depends on EROFS_FS 40 depends on EROFS_FS
41 select XXHASH 41 select XXHASH
42 default y 42 default y
43 help 43 help
44 Extended attributes are name:value p 44 Extended attributes are name:value pairs associated with inodes by
45 the kernel or by users (see the attr 45 the kernel or by users (see the attr(5) manual page, or visit
46 <http://acl.bestbits.at/> for detail 46 <http://acl.bestbits.at/> for details).
47 47
48 If unsure, say N. 48 If unsure, say N.
49 49
50 config EROFS_FS_POSIX_ACL 50 config EROFS_FS_POSIX_ACL
51 bool "EROFS Access Control Lists" 51 bool "EROFS Access Control Lists"
52 depends on EROFS_FS_XATTR 52 depends on EROFS_FS_XATTR
53 select FS_POSIX_ACL 53 select FS_POSIX_ACL
54 default y 54 default y
55 help 55 help
56 Posix Access Control Lists (ACLs) su 56 Posix Access Control Lists (ACLs) support permissions for users and
57 groups beyond the owner/group/world 57 groups beyond the owner/group/world scheme.
58 58
59 To learn more about Access Control L 59 To learn more about Access Control Lists, visit the POSIX ACLs for
60 Linux website <http://acl.bestbits.a 60 Linux website <http://acl.bestbits.at/>.
61 61
62 If you don't know what Access Contro 62 If you don't know what Access Control Lists are, say N.
63 63
64 config EROFS_FS_SECURITY 64 config EROFS_FS_SECURITY
65 bool "EROFS Security Labels" 65 bool "EROFS Security Labels"
66 depends on EROFS_FS_XATTR 66 depends on EROFS_FS_XATTR
67 default y 67 default y
68 help 68 help
69 Security labels provide an access co 69 Security labels provide an access control facility to support Linux
70 Security Models (LSMs) accepted by A 70 Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
71 Linux. This option enables an extend 71 Linux. This option enables an extended attribute handler for file
72 security labels in the erofs filesys 72 security labels in the erofs filesystem, so that it requires enabling
73 the extended attribute support in ad 73 the extended attribute support in advance.
74 74
75 If you are not using a security modu 75 If you are not using a security module, say N.
76 76
77 config EROFS_FS_BACKED_BY_FILE <<
78 bool "File-backed EROFS filesystem sup <<
79 depends on EROFS_FS <<
80 default y <<
81 help <<
82 This allows EROFS to use filesystem <<
83 the intercession of loopback block d <<
84 particularly useful for container im <<
85 other sandboxes, where loop devices <<
86 be used to simplify error-prone life <<
87 virtual block devices. <<
88 <<
89 Note that this feature, along with o <<
90 hooks, will eventually replace "EROF <<
91 <<
92 If you don't want to enable this fea <<
93 <<
94 config EROFS_FS_ZIP 77 config EROFS_FS_ZIP
95 bool "EROFS Data Compression Support" 78 bool "EROFS Data Compression Support"
96 depends on EROFS_FS 79 depends on EROFS_FS
97 select LZ4_DECOMPRESS 80 select LZ4_DECOMPRESS
98 default y 81 default y
99 help 82 help
100 Enable fixed-sized output compressio 83 Enable fixed-sized output compression for EROFS.
101 84
102 If you don't want to enable compress 85 If you don't want to enable compression feature, say N.
103 86
104 config EROFS_FS_ZIP_LZMA 87 config EROFS_FS_ZIP_LZMA
105 bool "EROFS LZMA compressed data suppo 88 bool "EROFS LZMA compressed data support"
106 depends on EROFS_FS_ZIP 89 depends on EROFS_FS_ZIP
107 select XZ_DEC 90 select XZ_DEC
108 select XZ_DEC_MICROLZMA 91 select XZ_DEC_MICROLZMA
109 help 92 help
110 Saying Y here includes support for r 93 Saying Y here includes support for reading EROFS file systems
111 containing LZMA compressed data, spe 94 containing LZMA compressed data, specifically called microLZMA. It
112 gives better compression ratios than 95 gives better compression ratios than the default LZ4 format, at the
113 expense of more CPU overhead. 96 expense of more CPU overhead.
114 97
115 If unsure, say N. 98 If unsure, say N.
116 99
117 config EROFS_FS_ZIP_DEFLATE 100 config EROFS_FS_ZIP_DEFLATE
118 bool "EROFS DEFLATE compressed data su 101 bool "EROFS DEFLATE compressed data support"
119 depends on EROFS_FS_ZIP 102 depends on EROFS_FS_ZIP
120 select ZLIB_INFLATE 103 select ZLIB_INFLATE
121 help 104 help
122 Saying Y here includes support for r 105 Saying Y here includes support for reading EROFS file systems
123 containing DEFLATE compressed data. 106 containing DEFLATE compressed data. It gives better compression
124 ratios than the default LZ4 format, 107 ratios than the default LZ4 format, while it costs more CPU
125 overhead. 108 overhead.
126 109
127 DEFLATE support is an experimental f 110 DEFLATE support is an experimental feature for now and so most
128 file systems will be readable withou 111 file systems will be readable without selecting this option.
129 112
130 If unsure, say N. 113 If unsure, say N.
131 114
132 config EROFS_FS_ZIP_ZSTD 115 config EROFS_FS_ZIP_ZSTD
133 bool "EROFS Zstandard compressed data 116 bool "EROFS Zstandard compressed data support"
134 depends on EROFS_FS_ZIP 117 depends on EROFS_FS_ZIP
135 select ZSTD_DECOMPRESS 118 select ZSTD_DECOMPRESS
136 help 119 help
137 Saying Y here includes support for r 120 Saying Y here includes support for reading EROFS file systems
138 containing Zstandard compressed data 121 containing Zstandard compressed data. It gives better compression
139 ratios than the default LZ4 format, 122 ratios than the default LZ4 format, while it costs more CPU
140 overhead. 123 overhead.
141 124
142 Zstandard support is an experimental 125 Zstandard support is an experimental feature for now and so most
143 file systems will be readable withou 126 file systems will be readable without selecting this option.
144 127
145 If unsure, say N. 128 If unsure, say N.
146 129
147 config EROFS_FS_ONDEMAND 130 config EROFS_FS_ONDEMAND
148 bool "EROFS fscache-based on-demand re !! 131 bool "EROFS fscache-based on-demand read support"
149 depends on EROFS_FS 132 depends on EROFS_FS
150 select NETFS_SUPPORT 133 select NETFS_SUPPORT
151 select FSCACHE 134 select FSCACHE
152 select CACHEFILES 135 select CACHEFILES
153 select CACHEFILES_ONDEMAND 136 select CACHEFILES_ONDEMAND
154 help 137 help
155 This permits EROFS to use fscache-ba 138 This permits EROFS to use fscache-backed data blobs with on-demand
156 read support. 139 read support.
157 <<
158 It is now deprecated and scheduled t <<
159 after fanotify pre-content hooks are <<
160 140
161 If unsure, say N. 141 If unsure, say N.
162 142
163 config EROFS_FS_PCPU_KTHREAD 143 config EROFS_FS_PCPU_KTHREAD
164 bool "EROFS per-cpu decompression kthr 144 bool "EROFS per-cpu decompression kthread workers"
165 depends on EROFS_FS_ZIP 145 depends on EROFS_FS_ZIP
166 help 146 help
167 Saying Y here enables per-CPU kthrea 147 Saying Y here enables per-CPU kthread workers pool to carry out
168 async decompression for low latencie 148 async decompression for low latencies on some architectures.
169 149
170 If unsure, say N. 150 If unsure, say N.
171 151
172 config EROFS_FS_PCPU_KTHREAD_HIPRI 152 config EROFS_FS_PCPU_KTHREAD_HIPRI
173 bool "EROFS high priority per-CPU kthr 153 bool "EROFS high priority per-CPU kthread workers"
174 depends on EROFS_FS_ZIP && EROFS_FS_PC 154 depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD
175 default y 155 default y
176 help 156 help
177 This permits EROFS to configure per- 157 This permits EROFS to configure per-CPU kthread workers to run
178 at higher priority. 158 at higher priority.
179 159
180 If unsure, say N. 160 If unsure, say N.
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