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553 lines
16 KiB
553 lines
16 KiB
.\" -*- nroff -*-
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.\" Copyright 2006 by Theodore Ts'o. All Rights Reserved.
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.\" This file may be copied under the terms of the GNU Public License.
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.\"
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.TH mke2fs.conf 5 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
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.SH NAME
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mke2fs.conf \- Configuration file for mke2fs
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.SH DESCRIPTION
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.I mke2fs.conf
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is the configuration file for
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.BR mke2fs (8).
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It controls the default parameters used by
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.BR mke2fs (8)
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when it is creating ext2, ext3, or ext4 filesystems.
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.PP
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The
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.I mke2fs.conf
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file uses an INI-style format. Stanzas, or top-level sections, are
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delimited by square braces: [ ]. Within each section, each line
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defines a relation, which assigns tags to values, or to a subsection,
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which contains further relations or subsections.
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.\" Tags can be assigned multiple values
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An example of the INI-style format used by this configuration file
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follows below:
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.P
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[section1]
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.br
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tag1 = value_a
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.br
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tag1 = value_b
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.br
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tag2 = value_c
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.P
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[section 2]
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.br
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tag3 = {
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.br
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subtag1 = subtag_value_a
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.br
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subtag1 = subtag_value_b
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.br
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subtag2 = subtag_value_c
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.br
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}
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.br
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tag1 = value_d
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.br
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tag2 = value_e
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.br
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}
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.P
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Comments are delimited by a semicolon (';') or a hash ('#') character
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at the beginning of the comment, and are terminated by the end of
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line character.
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.P
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Tags and values must be quoted using double quotes if they contain
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spaces. Within a quoted string, the standard backslash interpretations
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apply: "\en" (for the newline character),
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"\et" (for the tab character), "\eb" (for the backspace character),
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and "\e\e" (for the backslash character).
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.P
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Some relations expect a boolean value. The parser is quite liberal on
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recognizing ``yes'', '`y'', ``true'', ``t'', ``1'', ``on'', etc. as a
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boolean true value, and ``no'', ``n'', ``false'', ``nil'', ``0'',
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``off'' as a boolean false value.
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.P
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The following stanzas are used in the
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.I mke2fs.conf
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file. They will be described in more detail in future sections of this
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document.
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.TP
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.I [options]
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Contains relations which influence how mke2fs behaves.
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.TP
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.I [defaults]
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Contains relations which define the default parameters
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used by
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.BR mke2fs (8).
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In general, these defaults may be overridden by a definition in the
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.B fs_types
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stanza, or by a command-line option provided by the user.
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.TP
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.I [fs_types]
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Contains relations which define defaults that should be used for specific
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file system and usage types. The file system type and usage type can be
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specified explicitly using
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the
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.BR \-t and \-T
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options to
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.BR mke2fs (8),
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respectively.
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.TP
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.I [devices]
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Contains relations which define defaults for specific devices.
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.SH THE [options] STANZA
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The following relations are defined in the
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.I [options]
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stanza.
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.TP
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.I proceed_delay
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If this relation is set to a positive integer, then mke2fs will
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wait
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.I proceed_delay
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seconds after asking the user for permission to proceed and
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then continue, even if the
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user has not answered the question. Defaults to 0, which means to wait
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until the user answers the question one way or another.
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.TP
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.I sync_kludge
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If this relation is set to a positive integer, then while writing the
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inode table, mke2fs will request the operating system flush out pending
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writes to initialize the inode table every
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.I sync_kludge
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block groups. This is needed to work around buggy kernels that don't
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handle writeback throttling correctly.
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.SH THE [defaults] STANZA
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The following relations are defined in the
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.I [defaults]
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stanza.
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.TP
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.I fs_type
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This relation specifies the default filesystem type if the user does not
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specify it via the
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.B \-t
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option, or if
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.B mke2fs
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is not started using a program name of the form
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.BI mkfs. fs-type\fR.
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If both the user and the
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.B mke2fs.conf
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file do not specify a default filesystem type, mke2fs will use a
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default filesystem type of
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.I ext3
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if a journal was requested via a command-line option, or
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.I ext2
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if not.
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.TP
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.I undo_dir
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This relation specifies the directory where the undo file should be
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stored. It can be overridden via the
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.B E2FSPROGS_UNDO_DIR
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environment variable. If the directory location is set to the value
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.IR none ,
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.B mke2fs
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will not create an undo file.
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.PP
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In addition, any tags that can be specified in a per-file system tags
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subsection as defined below (e.g.,
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.IR blocksize ,
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.IR hash_alg ,
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.IR inode_ratio ,
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.IR inode_size ,
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.IR reserved_ratio ,
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etc.) can also be specified in the
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.I defaults
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stanza to specify the default value to be used if the user does not
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specify one on the command line, and the filesystem-type
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specific section of the configuration file does not specify a default value.
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.SH THE [fs_types] STANZA
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Each tag in the
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.I [fs_types]
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stanza names a filesystem type or usage type which can be specified via the
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.B \-t
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or
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.B \-T
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options to
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.BR mke2fs (8),
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respectively.
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.P
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The
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.B mke2fs
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program constructs a list of fs_types by concatenating the filesystem
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type (i.e., ext2, ext3, etc.) with the usage type list. For most
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configuration options,
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.B mke2fs
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will look for a subsection in the
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.I [fs_types]
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stanza corresponding with each entry in the constructed list, with later
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entries overriding earlier filesystem or usage types.
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For
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example, consider the following
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.B mke2fs.conf
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fragment:
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.P
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[defaults]
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.br
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base_features = sparse_super,filetype,resize_inode,dir_index
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.br
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blocksize = 4096
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.br
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inode_size = 256
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.br
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inode_ratio = 16384
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.br
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.br
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[fs_types]
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.br
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ext3 = {
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.br
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features = has_journal
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.br
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}
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.br
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ext4 = {
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.br
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features = extents,flex_bg
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.br
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inode_size = 256
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.br
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}
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.br
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small = {
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.br
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blocksize = 1024
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.br
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inode_ratio = 4096
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.br
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}
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.br
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floppy = {
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.br
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features = ^resize_inode
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.br
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blocksize = 1024
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.br
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inode_size = 128
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.br
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}
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.P
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If mke2fs started with a program name of
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.BR mke2fs.ext4 ,
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then the filesystem type of ext4 will be used. If the filesystem is
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smaller than 3 megabytes, and no usage type is specified, then
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.B mke2fs
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will use a default
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usage type of
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.IR floppy .
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This results in an fs_types list of "ext4, floppy". Both the ext4
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subsection and the floppy subsection define an
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.I inode_size
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relation, but since the later entries in the fs_types list supersede
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earlier ones, the configuration parameter for fs_types.floppy.inode_size
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will be used, so the filesystem will have an inode size of 128.
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.P
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The exception to this resolution is the
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.I features
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tag, which specifies a set of changes to the features used by the
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filesystem, and which is cumulative. So in the above example, first
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the configuration relation defaults.base_features would enable an
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initial feature set with the sparse_super, filetype, resize_inode, and
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dir_index features enabled. Then configuration relation
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fs_types.ext4.features would enable the extents and flex_bg
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features, and finally the configuration relation
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fs_types.floppy.features would remove
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the resize_inode feature, resulting in a filesystem feature set
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consisting of the sparse_super, filetype, dir_index,
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extents_and flex_bg features.
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.P
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For each filesystem type, the following tags may be used in that
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fs_type's subsection. These tags may also be used in the
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.I default
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section:
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.TP
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.I base_features
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This relation specifies the features which are initially enabled for this
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filesystem type. Only one
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.I base_features
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will be used, so if there are multiple entries in the fs_types list
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whose subsections define the
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.I base_features
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relation, only the last will be used by
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.BR mke2fs (8).
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.TP
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.I enable_periodic_fsck
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This boolean relation specifies whether periodic filesystem checks should be
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enforced at boot time. If set to true, checks will be forced every
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180 days, or after a random number of mounts. These values may
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be changed later via the
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.B -i
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and
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.B -c
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command-line options to
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.BR tune2fs (8).
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.TP
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.I errors
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Change the behavior of the kernel code when errors are detected.
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In all cases, a filesystem error will cause
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.BR e2fsck (8)
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to check the filesystem on the next boot.
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.I errors
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can be one of the following:
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.RS 1.2i
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.TP 1.2i
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.B continue
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Continue normal execution.
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.TP
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.B remount-ro
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Remount filesystem read-only.
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.TP
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.B panic
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Cause a kernel panic.
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.RE
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.TP
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.I features
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This relation specifies a comma-separated list of features edit
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requests which modify the feature set
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used by the newly constructed filesystem. The syntax is the same as the
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.B -O
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command-line option to
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.BR mke2fs (8);
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that is, a feature can be prefixed by a caret ('^') symbol to disable
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a named feature. Each
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.I feature
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relation specified in the fs_types list will be applied in the order
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found in the fs_types list.
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.TP
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.I force_undo
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This boolean relation, if set to a value of true, forces
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.B mke2fs
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to always try to create an undo file, even if the undo file might be
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huge and it might extend the time to create the filesystem image
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because the inode table isn't being initialized lazily.
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.TP
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.I default_features
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This relation specifies set of features which should be enabled or
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disabled after applying the features listed in the
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.I base_features
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and
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.I features
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relations. It may be overridden by the
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.B -O
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command-line option to
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.BR mke2fs (8).
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.TP
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.I auto_64-bit_support
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This relation is a boolean which specifies whether
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.BR mke2fs (8)
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|
should automatically add the 64bit feature if the number of blocks for
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the file system requires this feature to be enabled. The resize_inode
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feature is also automatically disabled since it doesn't support 64-bit
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block numbers.
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.TP
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.I default_mntopts
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This relation specifies the set of mount options which should be enabled
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by default. These may be changed at a later time with the
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.B -o
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command-line option to
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.BR tune2fs (8).
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.TP
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.I blocksize
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This relation specifies the default blocksize if the user does not
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specify a blocksize on the command line.
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.TP
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.I lazy_itable_init
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This boolean relation specifies whether the inode table should
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be lazily initialized. It only has meaning if the uninit_bg feature is
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enabled. If lazy_itable_init is true and the uninit_bg feature is
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enabled, the inode table will
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not be fully initialized by
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.BR mke2fs (8).
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This speeds up filesystem
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initialization noticeably, but it requires the kernel to finish
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initializing the filesystem in the background when the filesystem is
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first mounted.
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.TP
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.I lazy_journal_init
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This boolean relation specifies whether the journal inode should be
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lazily initialized. It only has meaning if the has_journal feature is
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enabled. If lazy_journal_init is true, the journal inode will not be
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fully zeroed out by
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.BR mke2fs .
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This speeds up filesystem initialization noticeably, but carries some
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small risk if the system crashes before the journal has been overwritten
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entirely one time.
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.TP
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.I journal_location
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This relation specifies the location of the journal.
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.TP
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.I num_backup_sb
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This relation indicates whether file systems with the
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.B sparse_super2
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feature enabled should be created with 0, 1, or 2 backup superblocks.
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.TP
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.I packed_meta_blocks
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This boolean relation specifies whether the allocation bitmaps, inode
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table, and journal should be located at the beginning of the file system.
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.TP
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.I inode_ratio
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This relation specifies the default inode ratio if the user does not
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specify one on the command line.
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.TP
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.I inode_size
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This relation specifies the default inode size if the user does not
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specify one on the command line.
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.TP
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.I reserved_ratio
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This relation specifies the default percentage of filesystem blocks
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reserved for the super-user, if the user does not specify one on the command
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line.
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.TP
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.I hash_alg
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This relation specifies the default hash algorithm used for the
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new filesystems with hashed b-tree directories. Valid algorithms
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accepted are:
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.IR legacy ,
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.IR half_md4 ,
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and
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.IR tea .
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.TP
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.I flex_bg_size
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This relation specifies the number of block groups that will be packed
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together to create one large virtual block group on an ext4 filesystem.
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This improves meta-data locality and performance on meta-data heavy
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workloads. The number of groups must be a power of 2 and may only be
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specified if the flex_bg filesystem feature is enabled.
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.TP
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.I options
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This relation specifies additional extended options which should be
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treated by
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.BR mke2fs (8)
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as if they were prepended to the argument of the
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.B -E
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option. This can be used to configure the default extended options used
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by
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.BR mke2fs (8)
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on a per-filesystem type basis.
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.TP
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.I discard
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This boolean relation specifies whether the
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.BR mke2fs (8)
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should attempt to discard device prior to filesystem creation.
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.TP
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.I cluster_size
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|
This relation specifies the default cluster size if the bigalloc file
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|
system feature is enabled. It can be overridden via the
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.B \-C
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command line option to
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.BR mke2fs (8)
|
|
.TP
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.I make_hugefiles
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|
This boolean relation enables the creation of pre-allocated files as
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|
part of formatting the file system. The extent tree blocks for these
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|
pre-allocated files will be placed near the beginning of the file
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system, so that if all of the other metadata blocks are also configured
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to be placed near the beginning of the file system (by disabling the
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backup superblocks, using the packed_meta_blocks option, etc.), the data
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blocks of the pre-allocated files will be contiguous.
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.TP
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.I hugefiles_dir
|
|
This relation specifies the directory where huge files are created,
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relative to the filesystem root.
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.TP
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.I hugefiles_uid
|
|
This relation controls the user ownership for all of the files and
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directories created by the
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.I make_hugefiles
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|
feature.
|
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.TP
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.I hugefiles_gid
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|
This relation controls the group ownership for all of the files and
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directories created by the
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.I make_hugefiles
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|
feature.
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.TP
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.I hugefiles_umask
|
|
This relation specifies the umask used when creating the files and
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directories by the
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.I make_hugefiles
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|
feature.
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.TP
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.I num_hugefiles
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|
This relation specifies the number of huge files to be created. If this
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relation is not specified, or is set to zero, and the
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.I hugefiles_size
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|
relation is non-zero, then
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.I make_hugefiles
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|
will create as many huge files as can fit to fill the entire file system.
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.TP
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.I hugefiles_slack
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|
This relation specifies how much space should be reserved for other
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files.
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.TP
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.I hugefiles_size
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|
This relation specifies the size of the huge files. If this relation is
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|
not specified, the default is to fill the entire file system.
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.TP
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.I hugefiles_align
|
|
This relation specifies the alignment for the start block of the huge
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files. It also forces the size of huge files to be a multiple of the
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requested alignment. If this relation is not specified, no alignment
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requirement will be imposed on the huge files.
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|
.TP
|
|
.I hugefiles_align_disk
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|
This relations specifies whether the alignment should be relative to the
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beginning of the hard drive (assuming that the starting offset of the
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partition is available to mke2fs). The default value is false, which
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will cause hugefile alignment to be relative to the beginning of the
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file system.
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.TP
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.I hugefiles_name
|
|
This relation specifies the base file name for the huge files.
|
|
.TP
|
|
.I hugefiles_digits
|
|
This relation specifies the (zero-padded) width of the field for the
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huge file number.
|
|
.TP
|
|
.I zero_hugefiles
|
|
This boolean relation specifies whether or not zero blocks will be
|
|
written to the hugefiles while
|
|
.BR mke2fs (8)
|
|
is creating them. By default, zero blocks will be written to the huge
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|
files to avoid stale data from being made available to potentially
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untrusted user programs, unless the device supports a discard/trim
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operation which will take care of zeroing the device blocks. By setting
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.I zero_hugefiles
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|
to false, this step will always be skipped, which can be useful if it is
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known that the disk has been previously erased, or if the user programs
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that will have access to the huge files are trusted to not reveal stale
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data.
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.TP
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.I encoding
|
|
This relation defines the file name encoding to be used if the casefold
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|
feature is enabled. Currently the only valid encoding is utf8-12.1 or
|
|
utf8, which requests the most recent Unicode version; since 12.1 is the only
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|
available Unicode version, utf8 and utf8-12.1 have the same result.
|
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.I encoding_flags
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|
This relation defines encoding-specific flags. For utf8 encodings, the
|
|
only available flag is strict, which will cause attempts to create file
|
|
names containing invalid Unicode characters to be rejected by the
|
|
kernel. Strict mode is not enabled by default.
|
|
.SH THE [devices] STANZA
|
|
Each tag in the
|
|
.I [devices]
|
|
stanza names device name so that per-device defaults can be specified.
|
|
.TP
|
|
.I fs_type
|
|
This relation specifies the default parameter for the
|
|
.B \-t
|
|
option, if this option isn't specified on the command line.
|
|
.TP
|
|
.I usage_types
|
|
This relation specifies the default parameter for the
|
|
.B \-T
|
|
option, if this option isn't specified on the command line.
|
|
.SH FILES
|
|
.TP
|
|
.I /etc/mke2fs.conf
|
|
The configuration file for
|
|
.BR mke2fs (8).
|
|
.SH SEE ALSO
|
|
.BR mke2fs (8)
|