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 77 config EROFS_FS_BACKED_BY_FILE
78 bool "File-backed EROFS filesystem sup 78 bool "File-backed EROFS filesystem support"
79 depends on EROFS_FS 79 depends on EROFS_FS
80 default y 80 default y
81 help 81 help
82 This allows EROFS to use filesystem 82 This allows EROFS to use filesystem image files directly, without
83 the intercession of loopback block d 83 the intercession of loopback block devices or likewise. It is
84 particularly useful for container im 84 particularly useful for container images with numerous blobs and
85 other sandboxes, where loop devices 85 other sandboxes, where loop devices behave intricately. It can also
86 be used to simplify error-prone life 86 be used to simplify error-prone lifetime management of unnecessary
87 virtual block devices. 87 virtual block devices.
88 88
89 Note that this feature, along with o 89 Note that this feature, along with ongoing fanotify pre-content
90 hooks, will eventually replace "EROF 90 hooks, will eventually replace "EROFS over fscache."
91 91
92 If you don't want to enable this fea 92 If you don't want to enable this feature, say N.
93 93
94 config EROFS_FS_ZIP 94 config EROFS_FS_ZIP
95 bool "EROFS Data Compression Support" 95 bool "EROFS Data Compression Support"
96 depends on EROFS_FS 96 depends on EROFS_FS
97 select LZ4_DECOMPRESS 97 select LZ4_DECOMPRESS
98 default y 98 default y
99 help 99 help
100 Enable fixed-sized output compressio 100 Enable fixed-sized output compression for EROFS.
101 101
102 If you don't want to enable compress 102 If you don't want to enable compression feature, say N.
103 103
104 config EROFS_FS_ZIP_LZMA 104 config EROFS_FS_ZIP_LZMA
105 bool "EROFS LZMA compressed data suppo 105 bool "EROFS LZMA compressed data support"
106 depends on EROFS_FS_ZIP 106 depends on EROFS_FS_ZIP
107 select XZ_DEC 107 select XZ_DEC
108 select XZ_DEC_MICROLZMA 108 select XZ_DEC_MICROLZMA
109 help 109 help
110 Saying Y here includes support for r 110 Saying Y here includes support for reading EROFS file systems
111 containing LZMA compressed data, spe 111 containing LZMA compressed data, specifically called microLZMA. It
112 gives better compression ratios than 112 gives better compression ratios than the default LZ4 format, at the
113 expense of more CPU overhead. 113 expense of more CPU overhead.
114 114
115 If unsure, say N. 115 If unsure, say N.
116 116
117 config EROFS_FS_ZIP_DEFLATE 117 config EROFS_FS_ZIP_DEFLATE
118 bool "EROFS DEFLATE compressed data su 118 bool "EROFS DEFLATE compressed data support"
119 depends on EROFS_FS_ZIP 119 depends on EROFS_FS_ZIP
120 select ZLIB_INFLATE 120 select ZLIB_INFLATE
121 help 121 help
122 Saying Y here includes support for r 122 Saying Y here includes support for reading EROFS file systems
123 containing DEFLATE compressed data. 123 containing DEFLATE compressed data. It gives better compression
124 ratios than the default LZ4 format, 124 ratios than the default LZ4 format, while it costs more CPU
125 overhead. 125 overhead.
126 126
127 DEFLATE support is an experimental f 127 DEFLATE support is an experimental feature for now and so most
128 file systems will be readable withou 128 file systems will be readable without selecting this option.
129 129
130 If unsure, say N. 130 If unsure, say N.
131 131
132 config EROFS_FS_ZIP_ZSTD 132 config EROFS_FS_ZIP_ZSTD
133 bool "EROFS Zstandard compressed data 133 bool "EROFS Zstandard compressed data support"
134 depends on EROFS_FS_ZIP 134 depends on EROFS_FS_ZIP
135 select ZSTD_DECOMPRESS 135 select ZSTD_DECOMPRESS
136 help 136 help
137 Saying Y here includes support for r 137 Saying Y here includes support for reading EROFS file systems
138 containing Zstandard compressed data 138 containing Zstandard compressed data. It gives better compression
139 ratios than the default LZ4 format, 139 ratios than the default LZ4 format, while it costs more CPU
140 overhead. 140 overhead.
141 141
142 Zstandard support is an experimental 142 Zstandard support is an experimental feature for now and so most
143 file systems will be readable withou 143 file systems will be readable without selecting this option.
144 144
145 If unsure, say N. 145 If unsure, say N.
146 146
147 config EROFS_FS_ONDEMAND 147 config EROFS_FS_ONDEMAND
148 bool "EROFS fscache-based on-demand re 148 bool "EROFS fscache-based on-demand read support (deprecated)"
149 depends on EROFS_FS 149 depends on EROFS_FS
150 select NETFS_SUPPORT 150 select NETFS_SUPPORT
151 select FSCACHE 151 select FSCACHE
152 select CACHEFILES 152 select CACHEFILES
153 select CACHEFILES_ONDEMAND 153 select CACHEFILES_ONDEMAND
154 help 154 help
155 This permits EROFS to use fscache-ba 155 This permits EROFS to use fscache-backed data blobs with on-demand
156 read support. 156 read support.
157 157
158 It is now deprecated and scheduled t 158 It is now deprecated and scheduled to be removed from the kernel
159 after fanotify pre-content hooks are 159 after fanotify pre-content hooks are landed.
160 160
161 If unsure, say N. 161 If unsure, say N.
162 162
163 config EROFS_FS_PCPU_KTHREAD 163 config EROFS_FS_PCPU_KTHREAD
164 bool "EROFS per-cpu decompression kthr 164 bool "EROFS per-cpu decompression kthread workers"
165 depends on EROFS_FS_ZIP 165 depends on EROFS_FS_ZIP
166 help 166 help
167 Saying Y here enables per-CPU kthrea 167 Saying Y here enables per-CPU kthread workers pool to carry out
168 async decompression for low latencie 168 async decompression for low latencies on some architectures.
169 169
170 If unsure, say N. 170 If unsure, say N.
171 171
172 config EROFS_FS_PCPU_KTHREAD_HIPRI 172 config EROFS_FS_PCPU_KTHREAD_HIPRI
173 bool "EROFS high priority per-CPU kthr 173 bool "EROFS high priority per-CPU kthread workers"
174 depends on EROFS_FS_ZIP && EROFS_FS_PC 174 depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD
175 default y 175 default y
176 help 176 help
177 This permits EROFS to configure per- 177 This permits EROFS to configure per-CPU kthread workers to run
178 at higher priority. 178 at higher priority.
179 179
180 If unsure, say N. 180 If unsure, say N.
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