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 comment field. The
-c only takes affect when the lock is being set using
the -d, -h, -n, -u, or -w options.
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System Administration Commands lockfs(1M)
-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 incon-
sistency. They may only be unlocked after successful
repair by fsck, which is usually done automatically (see
mountufs(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. Addi-
tional 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 sys-
tem, 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.
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System Administration Commands lockfs(1M)
-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(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
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System Administration Commands lockfs(1M)
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
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System Administration Commands lockfs(1M)
example#
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Availability SUNWcsu
SEE ALSO
kill(1), mountufs(1M), sync(1M), attributes(5), large-
file(5), ufs(7FS),
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.
SunOS 5.11 Last change: 2 Jan 2008 5
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