.\"
.TH TUNE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
.SH NAME
-tune2fs \- adjust tunable filesystem parameters on ext2/ext3 filesystems
+tune2fs \- adjust tunable filesystem parameters on ext2/ext3/ext4 filesystems
.SH SYNOPSIS
.B tune2fs
[
.RI [^] feature [,...]
]
[
+.B \-Q
+.I quota-options
+]
+[
.B \-T
.I time-last-checked
]
.B \-U
.I UUID
]
+[
+.B \-z
+.I undo_file
+]
device
.SH DESCRIPTION
.BI tune2fs
allows the system administrator to adjust various tunable filesystem
-parameters on Linux ext2/ext3 filesystems.
+parameters on Linux ext2, ext3, or ext4 filesystems. The current values
+of these options can be displayed by using the
+.B -l
+option to
+.BR tune2fs (8)
+program, or by using the
+.BR dumpe2fs (8)
+program.
+.PP
+The
+.I device
+specifier can either be a filename (i.e., /dev/sda1), or a LABEL or UUID
+specifier: "\fBLABEL=\fIvolume-name\fR" or "\fBUUID=\fIuuid\fR". (i.e.,
+LABEL=home or UUID=e40486c6-84d5-4f2f-b99c-032281799c9d).
.SH OPTIONS
.TP
.BI \-c " max-mount-counts"
The following extended options are supported:
.RS 1.2i
.TP
+.B clear_mmp
+Reset the MMP block (if any) back to the clean state. Use only if
+absolutely certain the device is not currently mounted or being
+fscked, or major filesystem corruption can result. Needs '-f'.
+.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 filesystem for a RAID array with
.I stride-size
and
.IR tea .
.TP
+.BI mount_opts= mount_option_string
+Set a set of default mount options which will be used when the file
+system is mounted. Unlike the bitmask-based default mount options which
+can be specified with the
+.B -o
+option,
+.I mount_option_string
+is an arbitrary string with a maximum length of 63 bytes, which is
+stored in the superblock.
+.IP
+The ext4 file system driver will first apply
+the bitmask-based default options, and then parse the
+.IR mount_option_string ,
+before parsing the mount options passed from the
+.BR mount (8)
+program.
+.IP
+This superblock setting is only honored in 2.6.35+ kernels;
+and not at all by the ext2 and ext3 file system drivers.
+.TP
.B test_fs
Set a flag in the filesystem superblock indicating that it may be
mounted using experimental kernel code, such as the ext4dev filesystem.
filesystem feature from a filesystem which has
an external journal (or is corrupted
such that it appears to have an external journal), but that
-external journal is not available.
+external journal is not available. If the filesystem appears to require
+journal replay, the
+.B \-f
+flag must be specified twice to proceed.
.sp
.B WARNING:
Removing an external journal from a filesystem which was not cleanly unmounted
.TP
.B \-i " \fIinterval-between-checks\fR[\fBd\fR|\fBm\fR|\fBw\fR]"
Adjust the maximal time between two filesystem checks.
-No postfix or
+No suffix or
.B d
-result in days,
+will interpret the number
+.I interval-between-checks
+as days,
.B m
-in months, and
+as months, and
.B w
-in weeks. A value of zero will disable the time-dependent checking.
+as weeks. A value of zero will disable the time-dependent checking.
.sp
It is strongly recommended that either
.B \-c
.I journal-size
megabytes. The size of the journal must be at least 1024 filesystem blocks
(i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.)
-and may be no more than 102,400 filesystem blocks.
+and may be no more than 10,240,000 filesystem blocks.
There must be enough free space in the filesystem to create a journal of
that size.
+.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.
@JDEV@.TP
@JDEV@.BI device= external-journal
@JDEV@Attach the filesystem to the journal block device located on
@JDEV@options can be given for a filesystem.
.TP
.B \-l
-List the contents of the filesystem superblock.
+List the contents of the filesystem superblock, including the current
+values of the parameters that can be set via this program.
.TP
.BI \-L " volume-label"
Set the volume label of the filesystem.
Enable debugging code for this filesystem.
.TP
.B bsdgroups
-Emulate BSD behaviour when creating new files: they will take the group-id
-of the directory in which they were created. The standard System V behaviour
+Emulate BSD behavior when creating new files: they will take the group-id
+of the directory in which they were created. The standard System V behavior
is the default, where newly created files take on the fsgid of the current
process, unless the directory has the setgid bit set, in which case it takes
the gid from the parent directory, and also gets the setgid bit set if it is
written into the main filesystem after its metadata has been committed
to the journal. This may increase throughput, however, it may allow old
data to appear in files after a crash and journal recovery.
+.TP
+.B nobarrier
+The file system will be mounted with barrier operations in the journal
+disabled. (This option is currently only supported by the ext4 file
+system driver in 2.6.35+ kernels.)
+.TP
+.B block_validity
+The file system will be mounted with the block_validity option enabled,
+which causes extra checks to be performed after reading or writing from
+the file system. This prevents corrupted metadata blocks from causing
+file system damage by overwriting parts of the inode table or block
+group descriptors. This comes at the cost of increased memory and CPU
+overhead, so it is enabled only for debugging purposes. (This option is
+currently only supported by the ext4 file system driver in 2.6.35+
+kernels.)
+.TP
+.B discard
+The file system will be mounted with the discard mount option. This will
+cause the file system driver to attempt to use the trim/discard feature
+of some storage devices (such as SSD's and thin-provisioned drives
+available in some enterprise storage arrays) to inform the storage
+device that blocks belonging to deleted files can be reused for other
+purposes. (This option is currently only supported by the ext4 file
+system driver in 2.6.35+ kernels.)
+.TP
+.B nodelalloc
+The file system will be mounted with the nodelalloc mount option. This
+will disable the delayed allocation feature. (This option is currently
+only supported by the ext4 file system driver in 2.6.35+ kernels.)
.RE
.TP
.BR \-O " [^]\fIfeature\fR[,...]"
features with commas. Filesystem features prefixed with a
caret character ('^') will be cleared in the filesystem's superblock;
filesystem features without a prefix character or prefixed with a plus
-character ('+') will be added to the filesystem.
+character ('+') will be added to the filesystem. For a detailed
+description of the file system features, please see the man page
+.BR ext4 (5).
.IP
The following filesystem features can be set or cleared using
.BR tune2fs :
.RS 1.2i
.TP
-.B large_file
-Filesystem can contain files that are greater than 2GB. (Modern kernels
-set this feature automatically when a file > 2GB is created.)
-.TP
.B dir_index
-Use hashed b-trees to speed up lookups in large directories.
+Use hashed b-trees to speed up lookups for large directories.
+.TP
+.B dir_nlink
+Allow more than 65000 subdirectories per directory.
+.TP
+.B extent
+Enable the use of extent trees to store the location of data blocks in inodes.
+.TP
+.B extra_isize
+Enable the extended inode fields used by ext4.
.TP
.B filetype
Store file type information in directory entries.
.TP
+.B flex_bg
+Allow bitmaps and inode tables for a block group to be placed
+anywhere on the storage media. \fBTune2fs\fR will not reorganize
+the location of the inode tables and allocation bitmaps, as
+.BR mke2fs (8)
+will do when it creates a freshly formatted file system with
+.B flex_bg
+enabled.
+.TP
.B has_journal
Use a journal to ensure filesystem consistency even across unclean shutdowns.
Setting the filesystem feature is equivalent to using the
.B \-j
option.
.TP
-.B sparse_super
-Limit the number of backup superblocks to save space on large filesystems.
+.B huge_file
+Support files larger than 2 terabytes in size.
+.TP
+.B large_file
+Filesystem can contain files that are greater than 2GB.
.TP
.B resize_inode
Reserve space so the block group descriptor table may grow in the
.B Tune2fs
only supports clearing this filesystem feature.
.TP
+.B mmp
+Enable or disable multiple mount protection (MMP) feature.
+.TP
+.B quota
+Enable internal file system quota inodes.
+.TP
+.B read-only
+Force the kernel to mount the file system read-only.
+.TP
+.B sparse_super
+Limit the number of backup superblocks to save space on large filesystems.
+.TP
.B uninit_bg
-Allow the kernel to initialize bitmaps and inode tables and keep a high
-watermark for the unused inodes in a filesystem, to reduce
+Allow the kernel to initialize bitmaps and inode tables lazily, and to
+keep a high watermark for the unused inodes in a filesystem, to reduce
.BR e2fsck (8)
time. This first e2fsck run after enabling this feature will take the
full time, but subsequent e2fsck runs will take only a fraction of the
.B e2fsck -D
can be run to convert existing directories to the hashed B-tree format.
Enabling certain filesystem features may prevent the filesystem from being
-mounted by kernels which do not support those features. In particular the
+mounted by kernels which do not support those features. In particular, the
.BR uninit_bg
and
.BR flex_bg
features are only supported by the ext4 filesystem.
.TP
+.BI \-p " mmp_check_interval"
+Set the desired MMP check interval in seconds. It is 5 seconds by default.
+.TP
.BI \-r " reserved-blocks-count"
Set the number of reserved filesystem blocks.
.TP
+.BI \-Q " quota-options"
+Sets 'quota' feature on the superblock and works on the quota files for the
+given quota type. Quota options could be one or more of the following:
+.RS 1.2i
+.TP
+.BR [^]usrquota
+Sets/clears user quota inode in the superblock.
+.TP
+.BR [^]grpquota
+Sets/clears group quota inode in the superblock.
+.TP
+.BR [^]prjquota
+Sets/clears project quota inode in the superblock.
+.RE
+.TP
.BI \-T " time-last-checked"
Set the time the filesystem was last checked using
.BR e2fsck .
.IR /dev/urandom ,
.B tune2fs
will automatically use a time-based UUID instead of a randomly-generated UUID.
+.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
+tune2fs-\fIdevice\fR.e2undo in the directory specified via the
+\fIE2FSPROGS_UNDO_DIR\fR environment variable.
+
+WARNING: The undo file cannot be used to recover from a power or system crash.
.SH BUGS
We haven't found any bugs yet. That doesn't mean there aren't any...
.SH AUTHOR
.BR debugfs (8),
.BR dumpe2fs (8),
.BR e2fsck (8),
-.BR mke2fs (8)
+.BR mke2fs (8),
+.BR ext4 (5)
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff