jfs_fsck(8) initiate replay of the JFS transaction log, and check and repair a JFS formatted device


jfs_fsck [ -afnpvV ] [ -j journal_device ] [ --omit_journal_replay ] [ --replay_journal_only ] device


jfs_fsck is used to replay the JFS transaction log, check a JFS formatted device for errors, and fix any errors found.

device is the special file name corresponding to the actual device to be checked (e.g. /dev/hdb1).

jfs_fsck must be run as root.


jfs_fsck should only be used to check an unmounted file system or a file system that is mounted READ ONLY. Using jfs_fsck to check a file system mounted other than READ ONLY could seriously damage the file system!


If no options are selected, the default is -p.

Autocheck mode - Replay the transaction log. Do not continue fsck processing unless the aggregate state is dirty or the log replay failed. Functionally equivalent to -p. Autocheck mode is typically the default mode used when jfs_fsck is called at boot time.
Replay the transaction log and force checking even if the file system appears clean. Repair all problems automatically.
-j journal_device
Specify the journal device.
Open the file system read only. Do not replay the transaction log. Report errors, but do not repair them.
Omit the replay of the transaction log. This option should not be used unless as a last resort (i.e. the log has been severely corrupted and replaying it causes further problems).
Automatically repair ("preen") the file system. Replay the transaction log. Do not continue fsck processing unless the aggregate state is dirty or the log replay failed. Functionally equivalent to -a.
Only replay the transaction log. Do not continue with a full file system check if the replay fails or if the file system is still dirty even after a journal replay. In general, this option should only be used for debugging purposes as it could leave the file system in an unmountable state. This option cannot be used with -f, -n, or --omit_journal_replay.
Verbose messaging - print details and debug statements to stdout.
Print version information and exit (regardless of any other chosen options).


Check the 3rd partition on the 2nd hard disk, print extended information to stdout, replay the transaction log, force complete jfs_fsck checking, and give permission to repair all errors:

jfs_fsck -v -f /dev/hdb3

Check the 5th partition on the 1st hard disk, and report, but do not repair, any errors:

jfs_fsck -n /dev/hda5


The exit code returned by jfs_fsck represents one of the following conditions:

No errors
File system errors corrected and/or transaction log replayed successfully
File system errors corrected, system should be rebooted if file system was mounted
File system errors left uncorrected
Operational error
Usage or syntax error
Shared library error


If you find a bug in JFS or jfs_fsck, please report it via the bug tracking system ("Report Bugs" section) of the JFS project web site:


Please send as much pertinent information as possible, including the complete output of running jfs_fsck with the -v option on the JFS device.


Barry Arndt  ([email protected])
William Braswell, Jr.
jfs_fsck is maintained by IBM.
See the JFS project web site for more details: