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NAME    [Toc]    [Back]

     fsck_ffs - Fast File System consistency check  and  interactive repair

SYNOPSIS    [Toc]    [Back]

     fsck_ffs -p [-f] [-m mode]
     fsck_ffs  [-f]  [-b  block#]  [-c level] [-y] [-n] [-m mode]
[filesystem] ...

DESCRIPTION    [Toc]    [Back]

     The first form of fsck_ffs preens a standard set of filesystems or the
     specified  filesystems.   It  is normally used in the script
/etc/rc during
     automatic reboot.  Here fsck_ffs reads the table  /etc/fstab
to determine
     which  filesystems  to check.  Only partitions in fstab that
are mounted
     ``rw'', ``rq'', or ``ro'' and have non-zero pass numbers are
     Filesystems  with  pass  number  1  (normally  just the root
filesystem) are
     checked one at a time.  When pass 1 completes, all remaining
     are  checked,  running one process per disk drive.  The disk
drive containing
 each filesystem is inferred from the longest  prefix  of
the device
     name  that ends in a digit; the remaining characters are assumed to be the
     partition designator.

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

     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
     filesystem on which the correction will take place, and  the
nature of the
     correction.   After  successfully  correcting  a filesystem,
fsck_ffs will
     print the number of files on that filesystem, the number  of
used and free
     blocks, and the percentage of fragmentation.

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

     Without the -p option, fsck_ffs audits and interactively repairs inconsistent
 conditions for filesystems.  If  the  filesystem  is
     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 filesystem, fsck_ffs will
default to a
     -n action.

     fsck has  more  consistency  checks  than  its  predecessors
check, dcheck,
     fcheck, and icheck combined.

     The following flags are interpreted by fsck_ffs:

     -f      Force checking of file systems.  Normally, if a file
system is
             cleanly unmounted, the kernel  will  set  a  ``clean
flag'' in the
             file  system  superblock and fsck_ffs will not check
the file system.
  This option forces fsck_ffs to check the  file
system, regardless
 of the state of the clean flag.

     -b block#
             Use  the  block specified as the super block for the
             Block 32 is usually an alternate super block.

     -m mode
             Use the mode specified in octal  as  the  permission
bits to use
             when  creating  the lost+found directory rather than
the default
             1700.  In particular, systems that wish to have lost
files accessible
  by  all users on the system should use a less
             set of permissions such as 755.

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

     -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 filesystem for writing.

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

             0        The filesystem is in the old (static table)

             1       The filesystem is in the new (dynamic table)

             2        The  filesystem  supports  32-bit  UIDs and
GIDs, short symbolic
 links are stored in the inode, and directories have
                     an added field showing the file type.

             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

             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
             In  preen mode, the conversion is listed and done if
             without user interaction.  Conversion in preen  mode
is best used
             when  all  the  filesystems  are  being converted at
once.  The format
             of a filesystem can be  determined  from  the  first
line of output
             from dumpfs(8).

     If  no filesystems are given to fsck_ffs then a default list
of filesystems
 is read from the file /etc/fstab.

     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
     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.
          Dot or dot-dot not the first two entries of a directory
or having
          the wrong inode number.
     8.   Super Block checks:
          More  blocks  for inodes than there are in the filesystem.
          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.

     Because of inconsistencies between the block device and  the
buffer cache,
     the raw device should always be used.

FILES    [Toc]    [Back]

     /etc/fstab  contains default list of filesystems to check

DIAGNOSTICS    [Toc]    [Back]

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

SEE ALSO    [Toc]    [Back]

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

OpenBSD      3.6                        November     29,     1994
[ Back ]
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