Provided by: ufsutils_8.2-3_amd64 bug


     fsck.ffs, fsck.ufs — file system consistency check and interactive repair


     fsck.ffs [-BFprfny] [-b block] [-c level] [-m mode] filesystem ...


     The specified disk partitions and/or file systems are checked.  In "preen" or "check clean"
     mode the clean flag of each file system's superblock is examined and only those file systems
     that are not marked clean are checked.  File systems are marked clean when they are
     unmounted, when they have been mounted read-only, or when fsck.ffs runs on them
     successfully.  If the -f option is specified, the file systems will be checked regardless of
     the state of their clean flag.

     The kernel takes care that only a restricted class of innocuous file system inconsistencies
     can happen unless hardware or software failures intervene.  These are limited to the

           Unreferenced inodes
           Link counts in inodes too large
           Missing blocks in the free map
           Blocks in the free map also in files
           Counts in the super-block wrong

     These are the only inconsistencies that fsck.ffs with the -p option will correct; if it
     encounters other inconsistencies, it exits with an abnormal return status and an automatic
     reboot will then fail.  For each corrected inconsistency one or more lines will be printed
     identifying the file system on which the correction will take place, and the nature of the
     correction.  After successfully correcting a file system, fsck.ffs will print the number of
     files on that file system, the number of used and free blocks, and the percentage of

     If sent a QUIT signal, fsck.ffs will finish the file system checks, then exit with an
     abnormal return status that causes an automatic reboot to fail.  This is useful when you
     want to finish the file system checks during an automatic reboot, but do not want the
     machine to come up multiuser after the checks complete.

     If fsck.ffs receives a SIGINFO (see the “status” argument for stty(1)) signal, a line will
     be written to the standard output indicating the name of the device currently being checked,
     the current phase number and phase-specific progress information.

     Without the -p option, fsck.ffs audits and interactively repairs inconsistent conditions for
     file systems.  If the file system is inconsistent the operator is prompted for concurrence
     before each correction is attempted.  It should be noted that some of the corrective actions
     which are not correctable under the -p option will result in some loss of data.  The amount
     and severity of data lost may be determined from the diagnostic output.  The default action
     for each consistency correction is to wait for the operator to respond yes or no.  If the
     operator does not have write permission on the file system fsck.ffs will default to a -n

     The following flags are interpreted by fsck.ffs:

     -F      Determine whether the file system needs to be cleaned immediately in foreground, or
             if its cleaning can be deferred to background.  To be eligible for background
             cleaning it must have been running with soft updates, not have been marked as
             needing a foreground check, and be mounted and writable when the background check is
             to be done.  If these conditions are met, then fsck.ffs exits with a zero exit
             status.  Otherwise it exits with a non-zero exit status.  If the file system is
             clean, it will exit with a non-zero exit status so that the clean status of the file
             system can be verified and reported during the foreground checks.  Note that when
             invoked with the -F flag, no cleanups are done.  The only thing that fsck.ffs does
             is to determine whether a foreground or background check is needed and exit with an
             appropriate status code.

     -B      A check is done on the specified and possibly active file system.  The set of
             corrections that can be done is limited to those done when running in preen mode
             (see the -p flag).  If unexpected errors are found, the file system is marked as
             needing a foreground check and fsck.ffs exits without attempting any further

     -b      Use the block specified immediately after the flag as the super block for the file
             system.  An alternate super block is usually located at block 32 for UFS1, and block
             160 for UFS2.

     -C      Check if file system was dismounted cleanly.  If so, skip file system checks (like
             "preen").  However, if the file system was not cleanly dismounted, do full checks,
             as if fsck.ffs was invoked without -C.

     -c      Convert the file system to the specified level.  Note that the level of a file
             system can only be raised.  There are currently four levels defined:

             0       The file system is in the old (static table) format.

             1       The file system is in the new (dynamic table) format.

             2       The file system supports 32-bit uid's and gid's, short symbolic links are
                     stored in the inode, and directories have an added field showing the file

             3       If maxcontig is greater than one, build the free segment maps to aid in
                     finding contiguous sets of blocks.  If maxcontig is equal to one, delete any
                     existing segment maps.

             In interactive mode, fsck.ffs will list the conversion to be made and ask whether
             the conversion should be done.  If a negative answer is given, no further operations
             are done on the file system.  In preen mode, the conversion is listed and done if
             possible without user interaction.  Conversion in preen mode is best used when all
             the file systems are being converted at once.  The format of a file system can be
             determined from the first line of output from dumpfs(8).

             This option implies the -f flag.

     -f      Force fsck.ffs to check ‘clean’ file systems when preening.

     -m      Use the mode specified in octal immediately after the flag as the permission bits to
             use when creating the lost+found directory rather than the default 1777.  In
             particular, systems that do not wish to have lost files accessible by all users on
             the system should use a more restrictive set of permissions such as 700.

     -n      Assume a no response to all questions asked by fsck.ffs except for ‘CONTINUE?’,
             which is assumed to be affirmative; do not open the file system for writing.

     -p      Preen file systems (see above).

     -r      Free up excess unused inodes.  Decreasing the number of preallocated inodes reduces
             the running time of future runs of fsck.ffs and frees up space that can allocated to
             files.  The -r option is ignored when running in preen mode.

     -y      Assume a yes response to all questions asked by fsck.ffs; this should be used with
             great caution as this is a free license to continue after essentially unlimited
             trouble has been encountered.

     Inconsistencies checked are as follows:

     1.   Blocks claimed by more than one inode or the free map.
     2.   Blocks claimed by an inode outside the range of the file system.
     3.   Incorrect link counts.
     4.   Size checks:
                Directory size not a multiple of DIRBLKSIZ.
                Partially truncated file.
     5.   Bad inode format.
     6.   Blocks not accounted for anywhere.
     7.   Directory checks:
                File pointing to unallocated inode.
                Inode number out of range.
                Directories with unallocated blocks (holes).
                Dot or dot-dot not the first two entries of a directory or having the wrong inode
     8.   Super Block checks:
                More blocks for inodes than there are in the file system.
                Bad free block map format.
                Total free block and/or free inode count incorrect.

     Orphaned files and directories (allocated but unreferenced) are, with the operator's
     concurrence, reconnected by placing them in the lost+found directory.  The name assigned is
     the inode number.  If the lost+found directory does not exist, it is created.  If there is
     insufficient space its size is increased.

     The full foreground fsck.ffs checks for many more problems that may occur after an
     unrecoverable disk write error.  Thus, it is recommended that you perform foreground
     fsck.ffs on your systems periodically and whenever you encounter unrecoverable disk write
     errors or file-system-related panics.


     /etc/fstab  contains default list of file systems to check.


     The fsck.ffs utility exits 0 on success, and >0 if an error occurs.

     If the option -F is used, fsck.ffs exits 7 if the file system is clean.


     The diagnostics produced by fsck.ffs are fully enumerated and explained in Appendix A of
     Fsck - The UNIX File System Check Program.


     fs(5), fstab(5), fsck(8), fsdb(8), reboot(8)