LOCKFS(8) Maintenance Commands and Procedures LOCKFS(8)

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 system 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 comment 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(8)). 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(8) 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 whitespace. Note that file-system
can be a directory rather than the specific name of a file system,
such as / or /usr. For example, if you specify /export/home as an
argument to a lockfs command and /export/home is mounted on the root
(/) file system, the lockfs command will take effect on the root file
system.

USAGE

See largefile(7) 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 comment 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#

SEE ALSO

kill(1), mount_ufs(8), sync(8), attributes(7), largefile(7), ufs(4FS),

DIAGNOSTICS

file system: Not owner

You must be root to use this command.


file system :Deadlock condition detected/avoided

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


file system: Device busy

Another process is setting the lock on file system.


January 2, 2008 LOCKFS(8)