NEWFS_EXT2FS(8) FreeBSD System Manager's Manual NEWFS_EXT2FS(8)
NAME
newfs_ext2fs - construct a new ext2 file system
SYNOPSIS
newfs_ext2fs [-FINqZ] [-b block-size] [-D inodesize] [-f frag-size]
[-i bytes-per-inode] [-m free-space] [-n inodes]
[-O filesystem-format] [-S sector-size] [-s size]
[-V verbose] [-v volname] special
DESCRIPTION
newfs_ext2fs is used to initialize and clear ext2 file systems before
first use. Before running newfs_ext2fs, the disk must be labeled using
disklabel(8). newfs_ext2fs builds a file system on the specified special
device, basing its defaults on the information in the disk label.
Typically the defaults are reasonable, although newfs_ext2fs has numerous
options to allow the defaults to be selectively overridden.
The special file should be a raw device, for example /dev/rsd0a; if a
relative path like sd0a is specified, the corresponding raw device is
used.
Options with numeric arguments may contain an optional (case-insensitive)
suffix:
b Bytes; causes no modification. (Default)
k Kilo; multiply the argument by 1024.
m Mega; multiply the argument by 1048576.
g Giga; multiply the argument by 1073741824.
The following options define the general layout policies.
-b block-size
The block size of the file system, in bytes. It must be a power
of two. The smallest allowable size is 1024 bytes. The default
size depends upon the size of the file system:
file system size block-size
<= 512 MB 1 KB
> 512 MB 4 KB
-D inodesize
Set the inode size. Defaults to 128, and can also be set to 256
for compatibility with ext4.
-F Create a file system image in special. The file system size
needs to be specified with "-s size". No attempts to use or
update the disk label will be made.
-f frag-size
The fragment size of the file system in bytes. It must be the
same as the blocksize, because the current ext2fs implementation
doesn't support fragmentation.
-I Do not require that the file system type listed in the disk label
is `ext2fs'.
-i bytes-per-inode
This specifies the density of inodes in the file system. If
fewer inodes are desired, a larger number should be used; to
create more inodes a smaller number should be given.
-m free-space
The percentage of space reserved from normal users; the minimum
free space threshold. The default value used is 5%.
-N Causes the file system parameters to be printed out without
really creating the file system.
-n inodes
This specifies the number of inodes for the file system. If both
-i and -n are specified then -n takes precedence. The default
number of inodes is calculated from a number of blocks in the
file system.
-O filesystem-format
Select the filesystem-format.
0 `GOOD_OLD_REV'; this option is primarily used to build
root file systems that can be understood by old or
dumb firmware for bootstrap. (default)
1 `DYNAMIC_REV'; various extended (and sometimes
incompatible) features are enabled (though not all
features are supported on OpenBSD). Currently only
the following features are supported:
RESIZE Prepare some reserved structures
which enable future file system
resizing.
FTYPE Store file types in directory
entries to improve performance.
SPARSESUPER Prepare superblock backups for the
fsck_ext2fs(8) utility on not all
but sparse block groups.
LARGEFILE Enable files larger than 2G bytes.
-q Operate in quiet mode. Equivalent to -V 1.
-s size
The size of the file system in sectors. An `s' suffix will be
interpreted as the number of sectors (the default). All other
suffixes are interpreted as per other numeric arguments, except
that the number is converted into sectors by dividing by the
sector size (as specified by -S secsize) after suffix
interpretation.
If no -s size is specified then the filesystem size defaults to
that of the partition or, if -F is specified, the existing file.
If size is negative, the specified size is subtracted from the
default size (reserving space at the end of the partition).
-V verbose
This controls the amount of information written to stdout:
0 No output.
1 Overall size and cylinder group details.
2 A progress bar (dots ending at right hand margin).
3 The first few super-block backup sector numbers are
displayed before the progress bar.
4 All the super-block backup sector numbers are
displayed (no progress bar).
The default is 4. If -N is specified, newfs_ext2fs stops before
outputting the progress bar.
-v volname
This specifies a volume name for the file system.
-Z Pre-zeros the file system image created with -F. This is
necessary if the image is to be used by vnd(4) (which doesn't
support file systems with `holes').
The following option overrides the standard sizes for the disk geometry.
The default value is taken from the disk label. Changing this default is
useful only when using newfs_ext2fs to build a file system whose raw
image will eventually be used on a different type of disk than the one on
which it is initially created (for example on a write-once disk). Note
that changing this value from its default will make it impossible for
fsck_ext2fs(8) to find the alternative superblocks if the standard
superblock is lost.
-S sector-size
The size of a sector in bytes (almost never anything but 512).
Defaults to 512.
NOTES
There is no option to specify the metadata byte order on the file system
to be created because the native ext2 file system is always little endian
even on big endian hosts.
The file system is created with `random' inode generation numbers to
improve NFS security.
The owner and group IDs of the root node and reserved blocks of the new
file system are set to the effective UID and GID of the user initializing
the file system.
For the newfs_ext2fs command to succeed, the disk label should first be
updated such that the fstype field for the partition is set to `ext2fs',
unless -F or -I is used.
The partition size is found using fstat(2), not by inspecting the disk
label. The block size and fragment size will be written back to the disk
label only if the last character of special references the same partition
as the minor device number.
SEE ALSO
fstat(2), disklabel(5), disktab(5), fs(5), disklabel(8), fsck_ext2fs(8),
mount(8), mount_ext2fs(8), newfs(8)
Remy Card, Theodore Ts'o, and Stephen Tweedie, "Design and Implementation
of the Second Extended Filesystem", The Proceedings of the First Dutch
International Symposium on Linux,
http://e2fsprogs.sourceforge.net/ext2intro.html.
HISTORY
The newfs_ext2fs command first appeared in OpenBSD 4.7.
AUTHORS
The newfs_ext2fs command was written by Izumi Tsutsui
<
[email protected]>.
BUGS
The newfs_ext2fs command is still experimental and there are few sanity
checks.
The newfs_ext2fs command doesn't have options to specify each REV1 file
system feature independently.
The newfs_ext2fs command doesn't support the bad block list accounted by
the bad blocks inode.
Many newer ext2 file system features (especially journaling) are not
supported yet.
Some features in file systems created by the newfs_ext2fs command might
not be recognized properly by the fsck_ext2fs(8) utility.
There is no native tool in the OpenBSD distribution for resizing ext2
file systems yet.
FreeBSD 14.1-RELEASE-p8 March 31, 2022 FreeBSD 14.1-RELEASE-p8