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.\" Copyright (c) 2019 Gao Xiang <>
mkfs.erofs \- tool to create an EROFS filesystem
EROFS is a new enhanced lightweight linux read-only filesystem with modern
designs (eg. no buffer head, reduced metadata, inline xattrs/data, etc.) for
scenarios which need high-performance read-only requirements, e.g. Android OS
for smartphones and LIVECDs.
It also provides fixed-sized output compression support, which improves storage
density, keeps relatively higher compression ratios, which is more useful to
achieve high performance for embedded devices with limited memory since it has
unnoticable memory overhead and page cache thrashing.
mkfs.erofs is used to create such EROFS filesystem \fIDESTINATION\fR image file
from \fISOURCE\fR directory.
.BI "\-z " compression-algorithm " [" ",#" "]"
Set an algorithm for file compression, which can be set with an optional
compression level separated by a comma.
.BI "\-d " #
Specify the level of debugging messages. The default is 0.
.BI "\-x " #
Specify the upper limit of an xattr which is still inlined. The default is 2.
Disable storing xattrs if < 0.
.BI "\-E " extended-option " [,...]"
Set extended options for the filesystem. Extended options are comma separated,
and may take an argument using the equals ('=') sign.
The following extended options are supported:
.RS 1.2i
.BI legacy-compress
Disable "decompression in-place" and "compacted indexes" support, which is used
when generating EROFS images for kernel version < 5.3.
.BI force-inode-compact
Forcely generate compact inodes (32-byte inodes) to output.
.BI force-inode-extended
Forcely generate extended inodes (64-byte inodes) to output.
.BI "\-T " #
Set all files to the given UNIX timestamp. Reproducible builds requires setting
all to a specific one.
.BI "\-U " UUID
Set the universally unique identifier (UUID) of the filesystem to
The format of the UUID is a series of hex digits separated by hyphens,
like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16".
.BI "\-\-exclude-path=" path
Ignore file that matches the exact literal path.
You may give multiple `--exclude-path' options.
.BI "\-\-exclude-regex=" regex
Ignore files that match the given regular expression.
You may give multiple `--exclude-regex` options.
.BI "\-\-file-contexts=" file
Specify a \fIfile_contexts\fR file to setup / override selinux labels.
.B \-\-help
Display this help and exit.
This version of \fBmkfs.erofs\fR is written by Li Guifu <>,
Miao Xie <> and Gao Xiang <> with
continuously improvements from others.
This manual page was written by Gao Xiang <>.
\fBmkfs.erofs\fR is part of erofs-utils package and is available from
.BR mkfs (8).