1MKFS.EROFS(1) General Commands Manual MKFS.EROFS(1)
2
6 mkfs.erofs - tool to create an EROFS filesystem
7
9 mkfs.erofs [OPTIONS] DESTINATION SOURCE
10
12 EROFS is a new enhanced lightweight linux read-only filesystem with
13 modern designs (eg. no buffer head, reduced metadata, inline xat‐
14 trs/data, etc.) for scenarios which need high-performance read-only re‐
15 quirements, e.g. Android OS for smartphones and LIVECDs.
16 It also provides fixed-sized output compression support, which improves
18 storage density, keeps relatively higher compression ratios, which is
19 more useful to achieve high performance for embedded devices with lim‐
20 ited memory since it has unnoticable memory overhead and page cache
21 thrashing.
22 mkfs.erofs is used to create such EROFS filesystem DESTINATION image
24 file from SOURCE directory.
25
27 -z compression-algorithm [,#]
28 Set an algorithm for file compression, which can be set with an
29 optional compression level separated by a comma.
30 -C max-pcluster-size
32 Specify the maximum size of compress physical cluster in bytes.
33 It may enable big pcluster feature if needed (Linux v5.13+).
34 -d # Specify the level of debugging messages. The default is 2, which
36 shows basic warning messages.
37 -x # Specify the upper limit of an xattr which is still inlined. The
39 default is 2. Disable storing xattrs if < 0.
40 -E extended-option [,...]
42 Set extended options for the filesystem. Extended options are
43 comma separated, and may take an argument using the equals ('=')
44 sign. The following extended options are supported:
45 legacy-compress
47 Disable "decompression in-place" and "compacted in‐
48 dexes" support, which is used when generating EROFS
49 images for kernel version < 5.3.
50 force-inode-compact
52 Forcely generate compact inodes (32-byte inodes) to
53 output.
54 force-inode-extended
56 Forcely generate extended inodes (64-byte inodes) to
57 output.
58 noinline_data
60 Don't inline regular files for FSDAX support (Linux
61 v5.15+).
62 force-inode-blockmap
64 Forcely generate inode chunk format in 4-byte block
65 address array.
66 force-chunk-indexes
68 Forcely generate inode chunk format in 8-byte chunk
69 indexes (with device id).
70 -T # Set all files to the given UNIX timestamp. Reproducible builds
72 requires setting all to a specific one.
73 -U UUID
75 Set the universally unique identifier (UUID) of the filesystem
76 to UUID. The format of the UUID is a series of hex digits sepa‐
77 rated by hyphens, like this:
78 "c1b9d5a2-f162-11cf-9ece-0020afc76f16".
79 --all-root
81 Make all files owned by root.
82 --blobdev file
84 Specify another extra blob device to store chunk-based data.
85 --chunksize #
87 Generate chunk-based files with #-byte chunks.
88 --compress-hints file
90 If the optional --compress-hints file argument is given,
91 mkfs.erofs uses it to apply the per-file compression strategy.
92 Each line is defined by tokens separated by spaces in the fol‐
93 lowing form:
94 <pcluster-in-bytes> <match-pattern>
95 --exclude-path=path
97 Ignore file that matches the exact literal path. You may give
98 multiple `--exclude-path' options.
99 --exclude-regex=regex
101 Ignore files that match the given regular expression. You may
102 give multiple `--exclude-regex` options.
103 --file-contexts=file
105 Specify a file_contexts file to setup / override selinux labels.
106 --force-uid=UID
108 Set all file uids to UID.
109 --force-gid=GID
111 Set all file gids to GID.
112 --help Display this help and exit.
114 --max-extent-bytes #
116 Specify maximum decompressed extent size # in bytes.
117
119 This version of mkfs.erofs is written by Li Guifu <blucer‐
120 lee@gmail.com>, Miao Xie <miaoxie@huawei.com> and Gao Xiang <xiang@ker‐
121 nel.org> with continuously improvements from others.
122 This manual page was written by Gao Xiang <xiang@kernel.org>.
124
126 mkfs.erofs is part of erofs-utils package and is available from
127 git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git.
128
130 mkfs(8).
131 MKFS.EROFS(1)