1 # SPDX-License-Identifier: GPL-2.0-only
4 tristate "EROFS filesystem support"
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
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.
23 See the documentation at <file:Documentation/filesystems/erofs.rst>
29 bool "EROFS debugging feature"
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.
39 bool "EROFS extended attributes"
43 Extended attributes are name:value pairs associated with inodes by
44 the kernel or by users (see the attr(5) manual page, or visit
45 <http://acl.bestbits.at/> for details).
49 config EROFS_FS_POSIX_ACL
50 bool "EROFS Access Control Lists"
51 depends on EROFS_FS_XATTR
55 Posix Access Control Lists (ACLs) support permissions for users and
56 groups beyond the owner/group/world scheme.
58 To learn more about Access Control Lists, visit the POSIX ACLs for
59 Linux website <http://acl.bestbits.at/>.
61 If you don't know what Access Control Lists are, say N.
63 config EROFS_FS_SECURITY
64 bool "EROFS Security Labels"
65 depends on EROFS_FS_XATTR
68 Security labels provide an access control facility to support Linux
69 Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
70 Linux. This option enables an extended attribute handler for file
71 security labels in the erofs filesystem, so that it requires enabling
72 the extended attribute support in advance.
74 If you are not using a security module, say N.
77 bool "EROFS Data Compression Support"
82 Enable fixed-sized output compression for EROFS.
84 If you don't want to enable compression feature, say N.
86 config EROFS_FS_ZIP_LZMA
87 bool "EROFS LZMA compressed data support"
88 depends on EROFS_FS_ZIP
90 select XZ_DEC_MICROLZMA
92 Saying Y here includes support for reading EROFS file systems
93 containing LZMA compressed data, specifically called microLZMA. it
94 gives better compression ratios than the LZ4 algorithm, at the
95 expense of more CPU overhead.
97 LZMA support is an experimental feature for now and so most file
98 systems will be readable without selecting this option.
102 config EROFS_FS_ONDEMAND
103 bool "EROFS fscache-based on-demand read support"
104 depends on CACHEFILES_ONDEMAND && (EROFS_FS=m && FSCACHE || EROFS_FS=y && FSCACHE=y)
107 This permits EROFS to use fscache-backed data blobs with on-demand
112 config EROFS_FS_PCPU_KTHREAD
113 bool "EROFS per-cpu decompression kthread workers"
114 depends on EROFS_FS_ZIP
116 Saying Y here enables per-CPU kthread workers pool to carry out
117 async decompression for low latencies on some architectures.
121 config EROFS_FS_PCPU_KTHREAD_HIPRI
122 bool "EROFS high priority per-CPU kthread workers"
123 depends on EROFS_FS_ZIP && EROFS_FS_PCPU_KTHREAD
125 This permits EROFS to configure per-CPU kthread workers to run