Ubuntu Manpage: mkfs.erofs - tool to create an EROFS filesystem

NAME

       mkfs.erofs - tool to create an EROFS filesystem

SYNOPSIS

       mkfs.erofs [OPTIONS] DESTINATION SOURCE

DESCRIPTION

       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 DESTINATION image file from SOURCE directory.

OPTIONS

-z compression-algorithm [,#]
Set an algorithm for file compression, which can be set with an optional compression level
separated by a comma.

-C max-pcluster-size
Specify the maximum size of compress physical cluster in bytes. It may enable big pcluster feature
if needed (Linux v5.13+).

-d # Specify the level of debugging messages. The default is 2, which shows basic warning messages.

-x # Specify the upper limit of an xattr which is still inlined. The default is 2. Disable storing
xattrs if < 0.

-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:

legacy-compress
Disable "decompression in-place" and "compacted indexes" support, which is used when
generating EROFS images for kernel version < 5.3.

force-inode-compact
Forcely generate compact inodes (32-byte inodes) to output.

force-inode-extended
Forcely generate extended inodes (64-byte inodes) to output.

noinline_data
Don't inline regular files for FSDAX support (Linux v5.15+).

force-inode-blockmap
Forcely generate inode chunk format in 4-byte block address array.

force-chunk-indexes
Forcely generate inode chunk format in 8-byte chunk indexes (with device id).

-T # Set all files to the given UNIX timestamp. Reproducible builds requires setting all to a specific
one.

-U UUID
Set the universally unique identifier (UUID) of the filesystem to UUID. The format of the UUID is
a series of hex digits separated by hyphens, like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16".

--all-root
Make all files owned by root.

--blobdev file
Specify another extra blob device to store chunk-based data.

--chunksize #
Generate chunk-based files with #-byte chunks.

--compress-hints file
If the optional --compress-hints file argument is given, mkfs.erofs uses it to apply the per-file
compression strategy. Each line is defined by tokens separated by spaces in the following form:
<pcluster-in-bytes> <match-pattern>

--exclude-path=path
Ignore file that matches the exact literal path. You may give multiple `--exclude-path' options.

--exclude-regex=regex
Ignore files that match the given regular expression. You may give multiple `--exclude-regex`
options.

--file-contexts=file
Specify a file_contexts file to setup / override selinux labels.

--force-uid=UID
Set all file uids to UID.

--force-gid=GID
Set all file gids to GID.

--help Display this help and exit.

--max-extent-bytes #
Specify maximum decompressed extent size # in bytes.

AUTHOR

       This  version  of  mkfs.erofs is written by Li Guifu <blucerlee@gmail.com>, Miao Xie <miaoxie@huawei.com>
       and Gao Xiang <xiang@kernel.org> with continuously improvements from others.

       This manual page was written by Gao Xiang <xiang@kernel.org>.

AVAILABILITY