Adding upstream version 4.22.0.upstream/4.22.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 891 insertions, 0 deletions

diff --git a/upstream/fedora-rawhide/man8/mkfs.ext2.8 b/upstream/fedora-rawhide/man8/mkfs.ext2.8
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+.\" -*- nroff -*-
+.\" Copyright 1993, 1994, 1995 by Theodore Ts'o.  All Rights Reserved.
+.\" This file may be copied under the terms of the GNU Public License.
+.\"
+.TH MKE2FS 8 "February 2023" "E2fsprogs version 1.47.0"
+.SH NAME
+mke2fs \- create an ext2/ext3/ext4 file system
+.SH SYNOPSIS
+.B mke2fs
+[
+.B \-c
+|
+.B \-l
+.I filename
+]
+[
+.B \-b
+.I block-size
+]
+[
+.B \-C
+.I cluster-size
+]
+[
+.B \-d
+.I root-directory
+]
+[
+.B \-D
+]
+[
+.B \-g
+.I blocks-per-group
+]
+[
+.B \-G
+.I number-of-groups
+]
+[
+.B \-i
+.I bytes-per-inode
+]
+[
+.B \-I
+.I inode-size
+]
+[
+.B \-j
+]
+[
+.B \-J
+.I journal-options
+]
+[
+.B \-N
+.I number-of-inodes
+]
+[
+.B \-n
+]
+[
+.B \-m
+.I reserved-blocks-percentage
+]
+[
+.B \-o
+.I creator-os
+]
+[
+.B \-O
+[^]\fIfeature\fR[,...]
+]
+[
+.B \-q
+]
+[
+.B \-r
+.I fs-revision-level
+]
+[
+.B \-E
+.I extended-options
+]
+[
+.B \-v
+]
+[
+.B \-F
+]
+[
+.B \-L
+.I volume-label
+]
+[
+.B \-M
+.I last-mounted-directory
+]
+[
+.B \-S
+]
+[
+.B \-t
+.I fs-type
+]
+[
+.B \-T
+.I usage-type
+]
+[
+.B \-U
+.I UUID
+]
+[
+.B \-V
+]
+[
+.B \-e
+.I errors-behavior
+]
+[
+.B \-z
+.I undo_file
+]
+.I device
+[
+.I fs-size
+]
+.sp
+.B "mke2fs \-O journal_dev"
+[
+.B \-b
+.I block-size
+]
+.\" No external-journal specific journal options yet (size is ignored)
+.\" [
+.\" .B \-J
+.\" .I journal-options
+.\" ]
+[
+.B \-L
+.I volume-label
+]
+[
+.B \-n
+]
+[
+.B \-q
+]
+[
+.B \-v
+]
+.I external-journal
+[
+.I fs-size
+]
+.SH DESCRIPTION
+.B mke2fs
+is used to create an ext2, ext3, or ext4 file system, usually in a disk
+partition (or file) named by
+.IR device .
+.PP
+The file system size is specified by
+.IR fs-size .
+If
+.I fs-size
+does not have a suffix, it is interpreted as power-of-two kilobytes,
+unless the
+.B \-b
+.I blocksize
+option is specified, in which case
+.I fs-size
+is interpreted as the number of
+.I blocksize
+blocks.   If the fs-size is suffixed by 'k', 'm', 'g', 't'
+(either upper-case or lower-case), then it is interpreted in
+power-of-two kilobytes, megabytes, gigabytes, terabytes, etc.
+If
+.I fs-size
+is omitted,
+.B mke2fs
+will create the file system based on the device size.
+.PP
+If
+.B mke2fs
+is run as
+.B mkfs.XXX
+(i.e.,
+.BR mkfs.ext2 ,
+.BR mkfs.ext3 ,
+or
+.BR mkfs.ext4 )
+the option
+.B \-t
+.I XXX
+is implied; so
+.B mkfs.ext3
+will create a file system for use with ext3,
+.B mkfs.ext4
+will create a file system for use with ext4, and so on.
+.PP
+The defaults of the parameters for the newly created file system, if not
+overridden by the options listed below, are controlled by the
+.B /etc/mke2fs.conf
+configuration file.  See the
+.BR mke2fs.conf (5)
+manual page for more details.
+.SH OPTIONS
+.TP
+.BI \-b " block-size"
+Specify the size of blocks in bytes.  Valid block-size values are powers of two
+from 1024 up to 65536 (however note that the kernel is able to mount only
+file systems with block-size smaller or equal to the system page size - 4k on
+x86 systems, up to 64k on ppc64 or aarch64 depending on kernel configuration).
+If omitted, block-size is heuristically determined by the file system size and
+the expected usage of the file system (see the
+.B \-T
+option).  In most common cases, the default block size is 4k. If
+.I block-size
+is preceded by a negative sign ('-'), then
+.B mke2fs
+will use heuristics to determine the
+appropriate block size, with the constraint that the block size will be
+at least
+.I block-size
+bytes.  This is useful for certain hardware devices which require that
+the blocksize be a multiple of 2k.
+.TP
+.B \-c
+Check the device for bad blocks before creating the file system.  If
+this option is specified twice, then a slower read-write
+test is used instead of a fast read-only test.
+.TP
+.B \-C " cluster-size"
+Specify the size of cluster in bytes for file systems using the bigalloc
+feature.  Valid cluster-size values are from 2048 to 256M bytes per
+cluster.  This can only be specified if the bigalloc feature is
+enabled.  (See the
+.B ext4 (5)
+man page for more details about bigalloc.)   The default cluster size if
+bigalloc is enabled is 16 times the block size.
+.TP
+.BI \-d " root-directory"
+Copy the contents of the given directory into the root directory of the
+file system.
+.TP
+.B \-D
+Use direct I/O when writing to the disk.  This avoids mke2fs dirtying a
+lot of buffer cache memory, which may impact other applications running
+on a busy server.  This option will cause mke2fs to run much more
+slowly, however, so there is a tradeoff to using direct I/O.
+.TP
+.BI \-e " error-behavior"
+Change the behavior of the kernel code when errors are detected.
+In all cases, a file system error will cause
+.BR e2fsck (8)
+to check the file system on the next boot.
+.I error-behavior
+can be one of the following:
+.RS 1.2i
+.TP 1.2i
+.B continue
+Continue normal execution.
+.TP
+.B remount-ro
+Remount file system read-only.
+.TP
+.B panic
+Cause a kernel panic.
+.RE
+.TP
+.BI \-E " extended-options"
+Set extended options for the file system.  Extended options are comma
+separated, and may take an argument using the equals ('=') sign.  The
+.B \-E
+option used to be
+.B \-R
+in earlier versions of
+.BR mke2fs .
+The
+.B \-R
+option is still accepted for backwards compatibility, but is deprecated.
+The following extended options are supported:
+.RS 1.2i
+.TP
+.BI encoding= encoding-name
+Enable the
+.I casefold
+feature in the super block and set
+.I encoding-name
+as the encoding to be used.  If
+.I encoding-name
+is not specified, the encoding defined in
+.BR mke2fs.conf (5)
+is used.
+.TP
+.BI encoding_flags= encoding-flags
+Define parameters for file name character encoding operations.  If a
+flag is not changed using this parameter, its default value is used.
+.I encoding-flags
+should be a comma-separated lists of flags to be enabled.  To disable a
+flag, add it to the list with the prefix "no".
+
+The only flag that can be set right now is
+.I strict
+which means that invalid strings should be rejected by the file system.
+In the default configuration, the
+.I strict
+flag is disabled.
+.TP
+.BI mmp_update_interval= interval
+Adjust the initial MMP update interval to
+.I interval
+seconds.  Specifying an
+.I interval
+of 0 means to use the default interval.  The specified interval must
+be less than 300 seconds.  Requires that the
+.B mmp
+feature be enabled.
+.TP
+.BI stride= stride-size
+Configure the file system for a RAID array with
+.I stride-size
+file system blocks. This is the number of blocks read or written to disk
+before moving to the next disk, which is sometimes referred to as the
+.I chunk size.
+This mostly affects placement of file system metadata like bitmaps at
+.B mke2fs
+time to avoid placing them on a single disk, which can hurt performance.
+It may also be used by the block allocator.
+.TP
+.BI stripe_width= stripe-width
+Configure the file system for a RAID array with
+.I stripe-width
+file system blocks per stripe. This is typically stride-size * N, where
+N is the number of data-bearing disks in the RAID (e.g. for RAID 5 there is one
+parity disk, so N will be the number of disks in the array minus 1).
+This allows the block allocator to prevent read-modify-write of the
+parity in a RAID stripe if possible when the data is written.
+.TP
+.BI offset= offset
+Create the file system at an offset from the beginning of the device or
+file.  This can be useful when creating disk images for virtual machines.
+.TP
+.BI resize= max-online-resize
+Reserve enough space so that the block group descriptor table can grow
+to support a file system that has
+.I max-online-resize
+blocks.
+.TP
+.B lazy_itable_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
+If enabled and the uninit_bg feature is enabled, the inode table will
+not be fully initialized by
+.BR mke2fs .
+This speeds up file system
+initialization noticeably, but it requires the kernel to finish
+initializing the file system in the background when the file system is
+first mounted.  If the option value is omitted, it defaults to 1 to
+enable lazy inode table zeroing.
+.TP
+.B lazy_journal_init\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
+If enabled, the journal inode will not be fully zeroed out by
+.BR mke2fs .
+This speeds up file system initialization noticeably, but carries some
+small risk if the system crashes before the journal has been overwritten
+entirely one time.  If the option value is omitted, it defaults to 1 to
+enable lazy journal inode zeroing.
+.TP
+.B assume_storage_prezeroed\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
+If enabled,
+.BR mke2fs
+assumes that the storage device has been prezeroed, skips zeroing the journal
+and inode tables, and annotates the block group flags to signal that the inode
+table has been zeroed.
+.TP
+.B no_copy_xattrs
+Normally
+.B mke2fs
+will copy the extended attributes of the files in the directory
+hierarchy specified via the (optional)
+.B \-d
+option.  This will disable the copy and leaves the files in the newly
+created file system without any extended attributes.
+.TP
+.BI num_backup_sb= <0|1|2>
+If the
+.B sparse_super2
+file system feature is enabled this option controls whether there will
+be 0, 1, or 2 backup superblocks created in the file system.
+.TP
+.B packed_meta_blocks\fR[\fB= \fI<0 to disable, 1 to enable>\fR]
+Place the allocation bitmaps and the inode table at the beginning of the
+disk.  This option requires that the flex_bg file system feature to be
+enabled in order for it to have effect, and will also create the journal
+at the beginning of the file system.  This option is useful for flash
+devices that use SLC flash at the beginning of the disk.
+It also maximizes the range of contiguous data blocks, which
+can be useful for certain specialized use cases, such as supported
+Shingled Drives.
+.TP
+.BI root_owner [=uid:gid]
+Specify the numeric user and group ID of the root directory.  If no UID:GID
+is specified, use the user and group ID of the user running \fBmke2fs\fR.
+In \fBmke2fs\fR 1.42 and earlier the UID and GID of the root directory were
+set by default to the UID and GID of the user running the mke2fs command.
+The \fBroot_owner=\fR option allows explicitly specifying these values,
+and avoid side-effects for users that do not expect the contents of the
+file system to change based on the user running \fBmke2fs\fR.
+.TP
+.B test_fs
+Set a flag in the file system superblock indicating that it may be
+mounted using experimental kernel code, such as the ext4dev file system.
+.TP
+.BI orphan_file_size= size
+Set size of the file for tracking unlinked but still open inodes and inodes
+with truncate in progress. Larger file allows for better scalability, reserving
+a few blocks per cpu is ideal.
+.TP
+.B discard
+Attempt to discard blocks at mkfs time (discarding blocks initially is useful
+on solid state devices and sparse / thin-provisioned storage). When the device
+advertises that discard also zeroes data (any subsequent read after the discard
+and before write returns zero), then mark all not-yet-zeroed inode tables as
+zeroed. This significantly speeds up file system initialization. This is set
+as default.
+.TP
+.B nodiscard
+Do not attempt to discard blocks at mkfs time.
+.TP
+.B quotatype
+Specify the which  quota types (usrquota, grpquota, prjquota) which
+should be enabled in the created file system.  The argument of this
+extended option should be a colon separated list.  This option has
+effect only if the
+.B quota
+feature is set.   The default quota types to be initialized if this
+option is not specified is both user and group quotas.  If the project
+feature is enabled that project quotas will be initialized as well.
+.RE
+.TP
+.B \-F
+Force
+.B mke2fs
+to create a file system, even if the specified device is not a partition
+on a block special device, or if other parameters do not make sense.
+In order to force
+.B mke2fs
+to create a file system even if the file system appears to be in use
+or is mounted (a truly dangerous thing to do), this option must be
+specified twice.
+.TP
+.BI \-g " blocks-per-group"
+Specify the number of blocks in a block group.  There is generally no
+reason for the user to ever set this parameter, as the default is optimal
+for the file system.  (For administrators who are creating
+file systems on RAID arrays, it is preferable to use the
+.I stride
+RAID parameter as part of the
+.B \-E
+option rather than manipulating the number of blocks per group.)
+This option is generally used by developers who
+are developing test cases.
+.IP
+If the bigalloc feature is enabled, the
+.B \-g
+option will specify the number of clusters in a block group.
+.TP
+.BI \-G " number-of-groups"
+Specify the number of block groups that will be packed together to
+create a larger virtual block group (or "flex_bg group") in an
+ext4 file system.  This improves meta-data locality and performance
+on meta-data heavy workloads.  The number of groups must be a power
+of 2 and may only be specified if the
+.B flex_bg
+file system feature is enabled.
+.TP
+.BI \-i " bytes-per-inode"
+Specify the bytes/inode ratio.
+.B mke2fs
+creates an inode for every
+.I bytes-per-inode
+bytes of space on the disk.  The larger the
+.I bytes-per-inode
+ratio, the fewer inodes will be created.  This value generally shouldn't
+be smaller than the blocksize of the file system, since in that case more
+inodes would be made than can ever be used.  Be warned that it is not
+possible to change this ratio on a file system after it is created, so be
+careful deciding the correct value for this parameter.  Note that resizing
+a file system changes the number of inodes to maintain this ratio.
+.TP
+.BI \-I " inode-size"
+Specify the size of each inode in bytes.
+The
+.I inode-size
+value must be a power of 2 larger or equal to 128.  The larger the
+.I inode-size
+the more space the inode table will consume, and this reduces the usable
+space in the file system and can also negatively impact performance.
+It is not
+possible to change this value after the file system is created.
+.IP
+File systems with an inode size of 128 bytes do not support timestamps
+beyond January 19, 2038.  Inodes which are 256 bytes or larger will
+support extended timestamps, project id's, and the ability to store some
+extended attributes in the inode table for improved performance.
+.IP
+The default inode size is controlled by the
+.BR mke2fs.conf (5)
+file.  In the
+.B mke2fs.conf
+file shipped with e2fsprogs, the default inode size is 256 bytes for
+most file systems, except for small file systems where the inode size
+will be 128 bytes.
+.TP
+.B \-j
+Create the file system with an ext3 journal.  If the
+.B \-J
+option is not specified, the default journal parameters will be used to
+create an appropriately sized journal (given the size of the file system)
+stored within the file system.  Note that you must be using a kernel
+which has ext3 support in order to actually make use of the journal.
+.TP
+.BI \-J " journal-options"
+Create the ext3 journal using options specified on the command-line.
+Journal options are comma
+separated, and may take an argument using the equals ('=')  sign.
+The following journal options are supported:
+.RS 1.2i
+.TP
+.BI size= journal-size
+Create an internal journal (i.e., stored inside the file system) of size
+.I journal-size
+megabytes.
+The size of the journal must be at least 1024 file system blocks
+(i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.)
+and may be no more than 10,240,000 file system blocks or half the total
+file system size (whichever is smaller)
+.TP
+.BI fast_commit_size= fast-commit-size
+Create an additional fast commit journal area of size
+.I fast-commit-size
+kilobytes.
+This option is only valid if
+.B fast_commit
+feature is enabled
+on the file system. If this option is not specified and if
+.B fast_commit
+feature is turned on, fast commit area size defaults to
+.I journal-size
+/ 64 megabytes. The total size of the journal with
+.B fast_commit
+feature set is
+.I journal-size
++ (
+.I fast-commit-size
+* 1024) megabytes. The total journal size may be no more than
+10,240,000 file system blocks or half the total file system size
+(whichever is smaller).
+.TP
+.BI location =journal-location
+Specify the location of the journal.  The argument
+.I journal-location
+can either be specified as a block number, or if the number has a units
+suffix (e.g., 'M', 'G', etc.) interpret it as the offset from the
+beginning of the file system.
+.TP
+.BI device= external-journal
+Attach the file system to the journal block device located on
+.IR external-journal .
+The external
+journal must already have been created using the command
+.IP
+.B mke2fs -O journal_dev
+.I external-journal
+.IP
+Note that
+.I external-journal
+must have been created with the
+same block size as the new file system.
+In addition, while there is support for attaching
+multiple file systems to a single external journal,
+the Linux kernel and
+.BR e2fsck (8)
+do not currently support shared external journals yet.
+.IP
+Instead of specifying a device name directly,
+.I external-journal
+can also be specified by either
+.BI LABEL= label
+or
+.BI UUID= UUID
+to locate the external journal by either the volume label or UUID
+stored in the ext2 superblock at the start of the journal.  Use
+.BR dumpe2fs (8)
+to display a journal device's volume label and UUID.  See also the
+.B -L
+option of
+.BR tune2fs (8).
+.RE
+.IP
+Only one of the
+.BR size " or " device
+options can be given for a file system.
+.TP
+.BI \-l " filename"
+Read the bad blocks list from
+.IR filename .
+Note that the block numbers in the bad block list must be generated
+using the same block size as used by
+.BR mke2fs .
+As a result, the
+.B \-c
+option to
+.B mke2fs
+is a much simpler and less error-prone method of checking a disk for bad
+blocks before formatting it, as
+.B mke2fs
+will automatically pass the correct parameters to the
+.B badblocks
+program.
+.TP
+.BI \-L " new-volume-label"
+Set the volume label for the file system to
+.IR new-volume-label .
+The maximum length of the
+volume label is 16 bytes.
+.TP
+.BI \-m " reserved-blocks-percentage"
+Specify the percentage of the file system blocks reserved for
+the super-user.  This avoids fragmentation, and allows root-owned
+daemons, such as
+.BR syslogd (8),
+to continue to function correctly after non-privileged processes are
+prevented from writing to the file system.  The default percentage
+is 5%.
+.TP
+.BI \-M " last-mounted-directory"
+Set the last mounted directory for the file system.  This might be useful
+for the sake of utilities that key off of the last mounted directory to
+determine where the file system should be mounted.
+.TP
+.B \-n
+Causes
+.B mke2fs
+to not actually create a file system, but display what it
+would do if it were to create a file system.  This can be used to
+determine the location of the backup superblocks for a particular
+file system, so long as the
+.B mke2fs
+parameters that were passed when the
+file system was originally created are used again.  (With the
+.B \-n
+option added, of course!)
+.TP
+.BI \-N " number-of-inodes"
+Overrides the default calculation of the number of inodes that should be
+reserved for the file system (which is based on the number of blocks and
+the
+.I bytes-per-inode
+ratio).  This allows the user to specify the number
+of desired inodes directly.
+.TP
+.BI \-o " creator-os"
+Overrides the default value of the "creator operating system" field of the
+file system.  The creator field is set by default to the name of the OS the
+.B mke2fs
+executable was compiled for.
+.TP
+.B "\-O \fR[^]\fIfeature\fR[,...]"
+Create a file system with the given features (file system options),
+overriding the default file system options.  The features that are
+enabled by default are specified by the
+.I base_features
+relation, either in the
+.I [defaults]
+section in the
+.B /etc/mke2fs.conf
+configuration file,
+or in the
+.I [fs_types]
+subsections for the usage types as specified by the
+.B \-T
+option, further modified by the
+.I features
+relation found in the
+.I [fs_types]
+subsections for the file system and usage types.  See the
+.BR mke2fs.conf (5)
+manual page for more details.
+The file system type-specific configuration setting found in the
+.I [fs_types]
+section will override the global default found in
+.IR [defaults] .
+.sp
+The file system feature set will be further edited
+using either the feature set specified by this option,
+or if this option is not given, by the
+.I default_features
+relation for the file system type being created, or in the
+.I [defaults]
+section of the configuration file.
+.sp
+The file system feature set is comprised of a list of features, separated
+by commas, that are to be enabled.  To disable a feature, simply
+prefix the feature name with a caret ('^') character.
+Features with dependencies will not be removed successfully.
+The pseudo-file system feature "none" will clear all file system features.
+.TP
+For more information about the features which can be set, please see
+the manual page
+.BR ext4 (5).
+.TP
+.B \-q
+Quiet execution.  Useful if
+.B mke2fs
+is run in a script.
+.TP
+.BI \-r " revision"
+Set the file system revision for the new file system.  Note that 1.2
+kernels only support revision 0 file systems.  The default is to
+create revision 1 file systems.
+.TP
+.B \-S
+Write superblock and group descriptors only.  This is an extreme
+measure to be taken only in the very unlikely case that all of
+the superblock and backup superblocks are corrupted, and a last-ditch
+recovery method is desired by experienced users.  It causes
+.B mke2fs
+to reinitialize the superblock and group descriptors, while not
+touching the inode table and the block and inode bitmaps.  The
+.B e2fsck
+program should be run immediately after this option is used, and there
+is no guarantee that any data will be salvageable.  Due to the wide
+variety of possible options to
+.B mke2fs
+that affect the on-disk layout, it is critical to specify exactly
+the same format options, such as blocksize, fs-type, feature flags, and
+other tunables when using this option, or the file system will be further
+corrupted.  In some cases, such as file systems that have been resized,
+or have had features enabled after format time, it is impossible to
+overwrite all of the superblocks correctly, and at least some file system
+corruption will occur.  It is best to run this on a full copy of the
+file system so other options can be tried if this doesn't work.
+.\" .TP
+.\" .BI \-t " test"
+.\" Check the device for bad blocks before creating the file system
+.\" using the specified test.
+.TP
+.BI \-t " fs-type"
+Specify the file system type (i.e., ext2, ext3, ext4, etc.) that is
+to be created.
+If this option is not specified,
+.B mke2fs
+will pick a default either via how
+the command was run (for example, using a name of the form mkfs.ext2,
+mkfs.ext3, etc.) or via a default as defined by the
+.B /etc/mke2fs.conf
+file.   This option controls which file system options are used by
+default, based on the
+.B fstypes
+configuration stanza in
+.BR /etc/mke2fs.conf .
+.sp
+If the
+.B \-O
+option is used to explicitly add or remove file system options that
+should be set in the newly created file system, the
+resulting file system may not be supported by the requested
+.IR fs-type .
+(e.g., "\fBmke2fs \-t ext3 \-O extent /dev/sdXX\fR" will create a
+file system that is not supported by the ext3 implementation as found in
+the Linux kernel; and "\fBmke2fs \-t ext3 \-O ^has_journal /dev/hdXX\fR"
+will create a file system that does not have a journal and hence will not
+be supported by the ext3 file system code in the Linux kernel.)
+.TP
+.BI \-T " usage-type[,...]"
+Specify how the file system is going to be used, so that
+.B mke2fs
+can choose optimal file system parameters for that use.  The usage
+types that are supported are defined in the configuration file
+.BR /etc/mke2fs.conf .
+The user may specify one or more usage types
+using a comma separated list.
+.sp
+If this option is is not specified,
+.B mke2fs
+will pick a single default usage type based on the size of the file system to
+be created.  If the file system size is less than 3 megabytes,
+.B mke2fs
+will use the file system type
+.IR floppy .
+If the file system size is greater than or equal to 3 but less than
+512 megabytes,
+.BR mke2fs (8)
+will use the file system type
+.IR small .
+If the file system size is greater than or equal to 4 terabytes but less than
+16 terabytes,
+.BR mke2fs (8)
+will use the file system type
+.IR big .
+If the file system size is greater than or equal to 16 terabytes,
+.BR mke2fs (8)
+will use the file system type
+.IR huge .
+Otherwise,
+.BR mke2fs (8)
+will use the default file system type
+.IR default .
+.TP
+.BI \-U " UUID"
+Set the universally unique identifier (UUID) of the file system to
+.IR UUID .
+The format of the UUID is a series of hex digits separated by hyphens,
+like this:
+"c1b9d5a2-f162-11cf-9ece-0020afc76f16".
+The
+.I UUID
+parameter may also be one of the following:
+.RS 1.2i
+.TP
+.I clear
+clear the file system UUID
+.TP
+.I random
+generate a new randomly-generated UUID
+.TP
+.I time
+generate a new time-based UUID
+.RE
+.TP
+.B \-v
+Verbose execution.
+.TP
+.B \-V
+Print the version number of
+.B mke2fs
+and exit.
+.TP
+.BI \-z " undo_file"
+Before overwriting a file system block, write the old contents of the block to
+an undo file.  This undo file can be used with e2undo(8) to restore the old
+contents of the file system should something go wrong.  If the empty string is
+passed as the undo_file argument, the undo file will be written to a file named
+mke2fs-\fIdevice\fR.e2undo in the directory specified via the
+\fIE2FSPROGS_UNDO_DIR\fR environment variable or the \fIundo_dir\fR directive
+in the configuration file.
+
+WARNING: The undo file cannot be used to recover from a power or system crash.
+.SH ENVIRONMENT
+.TP
+.B MKE2FS_SYNC
+If set to non-zero integer value, its value is used to determine how often
+.BR sync (2)
+is called during inode table initialization.
+.TP
+.B MKE2FS_CONFIG
+Determines the location of the configuration file (see
+.BR mke2fs.conf (5)).
+.TP
+.B MKE2FS_FIRST_META_BG
+If set to non-zero integer value, its value is used to determine first meta
+block group. This is mostly for debugging purposes.
+.TP
+.B MKE2FS_DEVICE_SECTSIZE
+If set to non-zero integer value, its value is used to determine logical
+sector size of the
+.IR device .
+.TP
+.B MKE2FS_DEVICE_PHYS_SECTSIZE
+If set to non-zero integer value, its value is used to determine physical
+sector size of the
+.IR device .
+.TP
+.B MKE2FS_SKIP_CHECK_MSG
+If set, do not show the message of file system automatic check caused by
+mount count or check interval.
+.SH AUTHOR
+This version of
+.B mke2fs
+has been written by Theodore Ts'o <tytso@mit.edu>.
+.SH AVAILABILITY
+.B mke2fs
+is part of the e2fsprogs package and is available from
+http://e2fsprogs.sourceforge.net.
+.SH SEE ALSO
+.BR mke2fs.conf (5),
+.BR badblocks (8),
+.BR dumpe2fs (8),
+.BR e2fsck (8),
+.BR tune2fs (8),
+.BR ext4 (5)