E2FSCK

Section: Maintenance Commands (8)
Updated: July 2000
Index Return to Main Contents

Copyright 1993, 1994, 1995 by Theodore Ts'o. All Rights Reserved.
This file may be copied under the terms of the GNU Public License.

NAME

e2fsck - check a Linux second extended file system

SYNOPSIS

e2fsck [ -pacnyrdfvstFSV ] [ -b superblock ] [ -B blocksize ] [ -l|-L bad_blocks_file ] [ -C fd ] device

DESCRIPTION

e2fsck is used to check a Linux second extended file system.

device: is the special file corresponding to the device (e.g /dev/hdc1).

OPTIONS

-a: This option does the same thing as the -p option. It is provided 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 location 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. 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 different 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 particular 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.
-C: 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).
-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.
-l filename: Add the blocks 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.
-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 backwards 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 conditions:
0 - No errors
1 - File system errors corrected
2 - File system errors corrected, system should
be rebooted if file system was mounted
4 - File system errors left uncorrected
8 - Operational error
16 - Usage or syntax error
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 <tytso@mit.edu>.

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