lslocks(8) — Linux manual page

LSLOCKS(8)                System Administration                LSLOCKS(8)

NAME         top

       lslocks - list local system locks

SYNOPSIS         top

       lslocks [options]

DESCRIPTION         top

       lslocks lists information about all the currently held file locks
       in a Linux system.

OPTIONS         top

       -b, --bytes
           Print sizes in bytes rather than in human-readable form.

           By default, sizes are shown in units that are powers of 1024
           bytes. The formal abbreviations for these units (KiB, MiB,
           GiB, ...) are further shortened to just their first letter: K,
           M, G, ....

       -H, --list-columns
           List the columns that can be specified with the --output
           option. Can be used with --json or --raw to get the list in a
           machine-readable format.

       -i, --noinaccessible
           Ignore lock files which are inaccessible for the current user.

       -J, --json
           Use JSON output format.

       -n, --noheadings
           Do not print a header line.

       -o, --output list
           Specify which output columns to print. Use --help to get a
           list of all supported columns.

           The default list of columns may be extended if list is
           specified in the format +list (e.g., lslocks -o +BLOCKER).

       --output-all
           Output all available columns.

       -p, --pid pid
           Display only the locks held by the process with this pid.

       -r, --raw
           Use the raw output format.

       -u, --notruncate
           Do not truncate text in columns.

       -h, --help
           Display help text and exit.

       -V, --version
           Display version and exit.

OUTPUT         top

       COMMAND
           The command name of the process holding the lock.

       PID
           The process ID of the process.

       TYPE
           The type of lock; can be LEASE (created with fcntl(2)), FLOCK
           (created with flock(2)), POSIX (created with fcntl(2) and
           lockf(3)) or OFDLCK (created with fcntl(2)).

       SIZE
           Size of the locked file.

       INODE
           The inode number.

       MAJ:MIN
           The major:minor device number.

       MODE
           The lock’s access permissions (read, write). If the process is
           blocked and waiting for the lock, then the mode is postfixed
           with an '*' (asterisk).

       M
           Whether the lock is mandatory; 0 means no (meaning the lock is
           only advisory), 1 means yes. (See fcntl(2).)

       START
           Relative byte offset of the lock.

       END
           Ending offset of the lock.

       PATH
           Full path of the lock. If none is found, or there are no
           permissions to read the path, it will fall back to the
           device’s mountpoint and "..." is appended to the path. The
           path might be truncated; use --notruncate to get the full
           path.

       BLOCKER
           The PID of the process which blocks the lock.

       HOLDERS
           The holder(s) of the lock. The format of the holder is
           PID,COMMAND,FD. If a lock is an open file description-oriented
           lock, there can be more than one holder for the lock. See the
           NOTES below.

NOTES         top

       The lslocks command is meant to replace the lslk(8) command,
       originally written by Victor A. Abell <abe@purdue.edu> and
       unmaintained since 2001.

       "The process holding the lock" for leases, FLOCK locks, and OFD
       locks is a fake-concept. They are associated with the open file
       description on which they are acquired. With fork(2) and/or
       cmsg(3), multiple processes can share an open file description. So
       the holder process of a lease (or a lock) is not uniquely
       determined. lslocks shows the one of the holder processes in
       COMMAND and PID columns.

AUTHORS         top

       Davidlohr Bueso <dave@gnu.org>

SEE ALSO         top

       flock(1), fcntl(2), lockf(3)

REPORTING BUGS         top

       For bug reports, use the issue tracker
       <https://github.com/util-linux/util-linux/issues>.

AVAILABILITY         top

       The lslocks command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>. This page is
       part of the util-linux (a random collection of Linux utilities)
       project. Information about the project can be found at 
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
       bug report for this manual page, send it to
       util-linux@vger.kernel.org. This page was obtained from the
       project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2025-08-11. (At that time, the date of the most recent commit that
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       or you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a
       mail to man-pages@man7.org

util-linux 2.42-start-521-ec46  2025-08-09                     LSLOCKS(8)

Pages that refer to this page: lsfd(1),  fcntl(2),  fcntl_locking(2),  flock(2),  proc_locks(5)

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