1# SPDX-License-Identifier: GPL-2.0-only
2
3config EROFS_FS
4	tristate "EROFS filesystem support"
5	depends on BLOCK
6	select CRC32
7	select FS_IOMAP
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 transparent compression and deduplication support to
17	  improve storage density and maintain relatively high compression
18	  ratios, and it implements in-place decompression to temporarily reuse
19	  page cache for compressed data using proper strategies, which is
20	  quite useful for ensuring guaranteed end-to-end runtime decompression
21	  performance under extreme 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
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_BACKED_BY_FILE
78	bool "File-backed EROFS filesystem support"
79	depends on EROFS_FS
80	default y
81	help
82	  This allows EROFS to use filesystem image files directly, without
83	  the intercession of loopback block devices or likewise. It is
84	  particularly useful for container images with numerous blobs and
85	  other sandboxes, where loop devices behave intricately.  It can also
86	  be used to simplify error-prone lifetime management of unnecessary
87	  virtual block devices.
88
89	  Note that this feature, along with ongoing fanotify pre-content
90	  hooks, will eventually replace "EROFS over fscache."
91
92	  If you don't want to enable this feature, say N.
93
94config EROFS_FS_ZIP
95	bool "EROFS Data Compression Support"
96	depends on EROFS_FS
97	select LZ4_DECOMPRESS
98	default y
99	help
100	  Enable transparent compression support for EROFS file systems.
101
102	  If you don't want to enable compression feature, say N.
103
104config EROFS_FS_ZIP_LZMA
105	bool "EROFS LZMA compressed data support"
106	depends on EROFS_FS_ZIP
107	select XZ_DEC
108	select XZ_DEC_MICROLZMA
109	help
110	  Saying Y here includes support for reading EROFS file systems
111	  containing LZMA compressed data, specifically called microLZMA. It
112	  gives better compression ratios than the default LZ4 format, at the
113	  expense of more CPU overhead.
114
115	  If unsure, say N.
116
117config EROFS_FS_ZIP_DEFLATE
118	bool "EROFS DEFLATE compressed data support"
119	depends on EROFS_FS_ZIP
120	select ZLIB_INFLATE
121	help
122	  Saying Y here includes support for reading EROFS file systems
123	  containing DEFLATE compressed data.  It gives better compression
124	  ratios than the default LZ4 format, while it costs more CPU
125	  overhead.
126
127	  DEFLATE support is an experimental feature for now and so most
128	  file systems will be readable without selecting this option.
129
130	  If unsure, say N.
131
132config EROFS_FS_ZIP_ZSTD
133	bool "EROFS Zstandard compressed data support"
134	depends on EROFS_FS_ZIP
135	select ZSTD_DECOMPRESS
136	help
137	  Saying Y here includes support for reading EROFS file systems
138	  containing Zstandard compressed data.  It gives better compression
139	  ratios than the default LZ4 format, while it costs more CPU
140	  overhead.
141
142	  Zstandard support is an experimental feature for now and so most
143	  file systems will be readable without selecting this option.
144
145	  If unsure, say N.
146
147config EROFS_FS_ZIP_ACCEL
148	bool "EROFS hardware decompression support"
149	depends on EROFS_FS_ZIP
150	help
151	  Saying Y here includes hardware accelerator support for reading
152	  EROFS file systems containing compressed data.  It gives better
153	  decompression speed than the software-implemented decompression, and
154	  it costs lower CPU overhead.
155
156	  Hardware accelerator support is an experimental feature for now and
157	  file systems are still readable without selecting this option.
158
159	  If unsure, say N.
160
161config EROFS_FS_ONDEMAND
162	bool "EROFS fscache-based on-demand read support (deprecated)"
163	depends on EROFS_FS
164	select NETFS_SUPPORT
165	select FSCACHE
166	select CACHEFILES
167	select CACHEFILES_ONDEMAND
168	help
169	  This permits EROFS to use fscache-backed data blobs with on-demand
170	  read support.
171
172	  It is now deprecated and scheduled to be removed from the kernel
173	  after fanotify pre-content hooks are landed.
174
175	  If unsure, say N.
176
177config EROFS_FS_PCPU_KTHREAD
178	bool "EROFS per-cpu decompression kthread workers"
179	depends on EROFS_FS_ZIP
180	help
181	  Saying Y here enables per-CPU kthread workers pool to carry out
182	  async decompression for low latencies on some architectures.
183
184	  If unsure, say N.
185
186config EROFS_FS_PCPU_KTHREAD_HIPRI
187	bool "EROFS high priority per-CPU kthread workers"
188	depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD
189	default y
190	help
191	  This permits EROFS to configure per-CPU kthread workers to run
192	  at higher priority.
193
194	  If unsure, say N.
195