System Administration Commands                         lockfs(1M)

NAME
     lockfs - change or report file system locks

SYNOPSIS
     /usr/sbin/lockfs [-adefhnuw] [-c string] [file-system...]

DESCRIPTION
     lockfs is used to change and report the status of file  sys-
     tem  locks.  lockfs  reports the lock status and unlocks the
     file systems that were improperly left locked.

     Using lockfs to lock a file system  is  discouraged  because
     this  requires  extensive knowledge of SunOS internals to be
     used effectively and correctly.

     When invoked with no arguments, lockfs lists  the  UFS  file
     systems  that  are  locked. If file-system is not specified,
     and -a is specified, lockfs is run on all mounted, UFS  type
     file systems.

OPTIONS
     The options are  mutually  exclusive:  wndheuf.  If  you  do
     specify  more  than one of these options on a lockfs command
     line, the utility does not protest and invokes only the last
     option specified.  In particular, you cannot specify a flush
     (-f) and a lock (for example, -w) on the same command  line.
     However,  all locking operations implicitly perform a flush,
     so the -f is superfluous when specifying a lock.

     You must be super-user to use any of the following  options,
     with the exception of -a, -f and -v.

     The following options are supported.

     -a              Apply command to all mounted, UFS type  file
                     systems.  file-system  is ignored when -a is
                     specified.



     -c string       Accept a string that is passed as  the  com-
                     ment  field.  The  -c only takes affect when
                     the lock is being set using the -d, -h,  -n,
                     -u, or -w options.



     -d              Delete-lock  (dlock)  the  specified   file-
                     system.  dlock  suspends  access  that could
                     remove directory entries.



     -e              Error-lock  (elock)  the   specified   file-
                     system. elock blocks all local access to the
                     locked file system and  returns  EWOULDBLOCK
                     on  all  remote  access.  File  systems  are
                     elocked by  UFS  on  detection  of  internal
                     inconsistency.  They  may  only  be unlocked
                     after successful repair by  fsck,  which  is
                     usually      done     automatically     (see
                     mount_ufs(1M)).  elocked file systems can be
                     unmounted.



     -f              Force a synchronous flush of all  data  that
                     is  dirty  at the time fsflush is run to its
                     backing store for the named file system  (or
                     for all file systems.)

                     It is a  more  reliable  method  than  using
                     sync(1M)  because  it  does not return until
                     all possible data has been  pushed.  In  the
                     case   of   UFS   filesystems  with  logging
                     enabled,  the  log  is  also  rolled  before
                     returning.   Additional data can be modified
                     by the time fsflush exits, so using  one  of
                     the  locking options is more likely to be of
                     general use.



     -h              Hard-lock (hlock) the specified file-system.
                     hlock  returns  an  error on every access to
                     the  locked  file  system,  and  cannot   be
                     unlocked.   hlocked   file  systems  can  be
                     unmounted.



     -n              Name-lock (nlock) the specified file-system.
                     nlock suspends accesses that could change or
                     remove existing directories entries.



     -u              Unlock (ulock)  the  specified  file-system.
                     ulock awakens suspended accesses.



     -v              Enable verbose output.




     -w              Write-lock  (wlock)  the   specified   file-
                     system.  wlock  suspends  writes  that would
                     modify the file system. Access times are not
                     kept while a file system is write-locked.



OPERANDS
     The following operands are supported.

     file-system     A list of  path  names  separated  by  white
                     spaces.



USAGE
     See largefile(5) for the  description  of  the  behavior  of
     lockfs  when  encountering  files greater than or equal to 2
     Gbyte ( 2**31 bytes).

EXAMPLES
     Example 1: Using lockfs -a

     In the following examples, filesystem is the pathname of the
     mounted-on  directory  (mount  point).  Locktype  is  one of
     "write,"  "name,"  "delete,"  "hard,"  or  "unlock".    When
     enclosed in parenthesis, the lock is being set. Comment is a
     string set by the process that last issued a lock command.

     The following example shows the lockfs output when only  the
     -a option is specified.

     example#  /usr/sbin/lockfs -a

     Filesystem           Locktype               Comment
     /                    unlock
     /var                 unlock


     example#

     Example 2: Using lockfs -w

     The following example shows the lockfs output  when  the  -w
     option  is  used  to write lock the /var file system and the
     comment string is set using the -c option.
      The -a option is then specified on a separate command line.

     example#  /usr/sbin/lockfs -w -c "lockfs: write lock example" /var
     example#  /usr/sbin/lockfs -a

     Filesystem           Locktype              Comment

     /                    unlock
     /var                 write                 lockfs: write lock example


     example#

     Example 3: Using lockfs -u

     The following example shows the lockfs output  when  the  -u
     option  is  used to unlock the /var file system and the com-
     ment string is set using the -c option.

     example#  /usr/sbin/lockfs -uc "lockfs: unlock example" /var
     example#  /usr/sbin/lockfs /var

     Filesystem           Locktype              Comment
     /var                 unlock                lockfs: unlock example


     example#

ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:

     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Availability                | SUNWcsu                     |
    |_____________________________|_____________________________|


SEE ALSO
     kill(1),  mount_ufs(1M),  sync(1M),  attributes(5),   large-
     file(5), ufs(7FS),

     System Administration Guide: Basic Administration

DIAGNOSTICS
     file system: Not owner

         You must be root to use this command.



     file system :Deadlockcondition detected/avoided

         A file is enabled for accounting or  swapping,  on  file
         system.


     file system: Devicebusy

         Another process is setting the lock on file system.