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| System Administration Commands | lockfs(1M) |
| | lockfs - change or report file system
locks |
SYNOPSIS
| | /usr/sbin/lockfs [-adefhnuw] [-c string] [file-system ...] |
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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.
The following options (described below) 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.
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The following options are supported. You must be super-user to use
any of the following options, with the exception of -a.
- -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(1M)).
elocked file systems can be unmounted.
- -f
- Flush all transactions
out of the log and write the transactions to the master file system. This
option is valid only if logging has been enabled on the file system.
- -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.
- -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.
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The following operands are supported.
-
file-system
- A list of path names separated
by white spaces.
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See largefile(5)
for the description of the behavior of lockfs when encountering
files greater than or equal to 2 Gbyte ( 231
bytes).
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| | Example 1. lockfs with the a option.
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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#
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Example 2. lockfs with the w option.
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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.
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example# /usr/sbin/lockfs -w -c "lockfs: write lock example" /var
example# /usr/sbin/lockfs -a
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| Filesystem | Locktype | Comment |
| / | unlock | |
| /var | write | lockfs: write lock example |
example#
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Example 3. lockfs with the u option.
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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.
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example# /usr/sbin/lockfs -uc "lockfs: unlock example" /var
example# /usr/sbin/lockfs /var
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| Filesystem | Locktype | Comment |
| /var | unlock | lockfs: unlock example |
example#
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See attributes(5)
for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| Availability | SUNWcsu |
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-
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.
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