E2FSCK linux command manual
E2FSCK(8) E2FSCK(8)
NAME
e2fsck - check a Linux ext2/ext3 file system
SYNOPSIS
e2fsck [ -pacnyrdfkvstDFSV ] [ -b superblock ] [ -B blocksize ] [
-l|-L bad_blocks_file ] [ -C fd ] [ -j external-journal ] [ -E
extended_options ] device
DESCRIPTION
e2fsck is used to check a Linux second extended file system (ext2fs).
E2fsck also supports ext2 filesystems countaining a journal, which are
also sometimes known as ext3 filesystems, by first applying the jour-
nal to the filesystem before continuing with normal e2fsck processing.
After the journal has been applied, a filesystem will normally be
marked as clean. Hence, for ext3 filesystems, e2fsck will normally
run the journal and exit, unless its superblock indicates that further
checking is required.
device is the device file where the filesystem is stored (e.g.
/dev/hdc1).
OPTIONS
-a This option does the same thing as the -p option. It is pro-
vided for backwards compatibility only; it is suggested that
people use -p option whenever possible.
-b superblock
Instead of using the normal superblock, use an alternative
superblock specified by superblock. This option is normally
used when the primary superblock has been corrupted. The loca-
tion of the backup superblock is dependent on the filesystem's
blocksize. For filesystems with 1k blocksizes, a backup
superblock can be found at block 8193; for filesystems with 2k
blocksizes, at block 16384; and for 4k blocksizes, at block
32768.
Additional backup superblocks can be determined by using the
mke2fs program using the -n option to print out where the
superblocks were created. The -b option to mke2fs, which
specifies blocksize of the filesystem must be specified in
order for the superblock locations that are printed out to be
accurate.
If an alternative superblock is specified and the filesystem is
not opened read-only, e2fsck will make sure that the primary
superblock is updated appropriately upon completion of the
filesystem check.
-B blocksize
Normally, e2fsck will search for the superblock at various dif-
ferent block sizes in an attempt to find the appropriate block
size. This search can be fooled in some cases. This option
forces e2fsck to only try locating the superblock at a particu-
lar blocksize. If the superblock is not found, e2fsck will
terminate with a fatal error.
-c This option causes e2fsck to run the badblocks(8) program to
find any blocks which are bad on the filesystem, and then marks
them as bad by adding them to the bad block inode. If this
option is specified twice, then the bad block scan will be done
using a non-destructive read-write test.
-C fd This option causes e2fsck to write completion information to
the specified file descriptor so that the progress of the
filesystem check can be monitored. This option is typically
used by programs which are running e2fsck. If the file
descriptor specified is 0, e2fsck will print a completion bar
as it goes about its business. This requires that e2fsck is
running on a video console or terminal.
-d Print debugging output (useless unless you are debugging
e2fsck).
-D Optimize directories in filesystem. This option causes e2fsck
to try to optimize all directories, either by reindexing them
if the filesystem supports directory indexing, or by sorting
and compressing directories for smaller directories, or for
filesystems using traditional linear directories.
-E extended_options
Set e2fsck extended options. Extended options are comma sepa-
rated, and may take an argument using the equals ('=') sign.
The following options are supported:
ea_ver=extended_attribute_version
Assume the format of the extended attribute blocks
in the filesystem is the specified version number.
The version number may be 1 or 2. The default
extended attribute version format is 2.
-f Force checking even if the file system seems clean.
-F Flush the filesystem device's buffer caches before beginning.
Only really useful for doing e2fsck time trials.
-j external-journal
Set the pathname where the external-journal for this filesystem
can be found.
-k When combined with the -c option, any existing bad blocks in
the bad blocks list are preserved, and any new bad blocks found
by running badblocks(8) will be added to the existing bad
blocks list.
-l filename
Add the block numbers listed in the file specified by filename
to the list of bad blocks. The format of this file is the same
as the one generated by the badblocks(8) program. Note that
the block numbers are based on the blocksize of the filesystem.
Hence, badblocks(8) must be given the blocksize of the filesys-
tem in order to obtain correct results. As a result, it is
much simpler and safer to use the -c option to e2fsck, since it
will assure that the correct parameters are passed to the bad-
blocks program.
-L filename
Set the bad blocks list to be the list of blocks specified by
filename. (This option is the same as the -l option, except
the bad blocks list is cleared before the blocks listed in the
file are added to the bad blocks list.)
-n Open the filesystem read-only, and assume an answer of 'no' to
all questions. Allows e2fsck to be used non-interactively.
(Note: if the -c, -l, or -L options are specified in addition
to the -n option, then the filesystem will be opened read-
write, to permit the bad-blocks list to be updated. However,
no other changes will be made to the filesystem.)
-p Automatically repair ("preen") the file system without any
questions.
-r This option does nothing at all; it is provided only for back-
wards compatibility.
-s This option will byte-swap the filesystem so that it is using
the normalized, standard byte-order (which is i386 or little
endian). If the filesystem is already in the standard byte-
order, e2fsck will take no action.
-S This option will byte-swap the filesystem, regardless of its
current byte-order.
-t Print timing statistics for e2fsck. If this option is used
twice, additional timing statistics are printed on a pass by
pass basis.
-v Verbose mode.
-V Print version information and exit.
-y Assume an answer of 'yes' to all questions; allows e2fsck to be
used non-interactively.
EXIT CODE
The exit code returned by e2fsck is the sum of the following condi-
tions:
0 - No errors
1 - File system errors corrected
2 - File system errors corrected, system should
be rebooted
4 - File system errors left uncorrected
8 - Operational error
16 - Usage or syntax error
32 - E2fsck canceled by user request
128 - Shared library error
SIGNALS
The following signals have the following effect when sent to e2fsck.
SIGUSR1
This signal causes e2fsck to start displaying a completion bar.
(See discussion of the -C option.)
SIGUSR2
This signal causes e2fsck to stop displaying a completion bar.
REPORTING BUGS
Almost any piece of software will have bugs. If you manage to find a
filesystem which causes e2fsck to crash, or which e2fsck is unable to
repair, please report it to the author.
Please include as much information as possible in your bug report.
Ideally, include a complete transcript of the e2fsck run, so I can see
exactly what error messages are displayed. If you have a writeable
filesystem where the transcript can be stored, the script(1) program
is a handy way to save the output of e2fsck to a file.
It is also useful to send the output of dumpe2fs(8). If a specific
inode or inodes seems to be giving e2fsck trouble, try running the
debugfs(8) command and send the output of the stat(1u) command run on
the relevant inode(s). If the inode is a directory, the debugfs dump
command will allow you to extract the contents of the directory inode,
which can sent to me after being first run through uuencode(1).
Always include the full version string which e2fsck displays when it
is run, so I know which version you are running.
AUTHOR
This version of e2fsck was written by Theodore Ts'o .
SEE ALSO
mke2fs(8), tune2fs(8), dumpe2fs(8), debugfs(8)
E2fsprogs version 1.35 February 2004 E2FSCK(8)