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Diffstat (limited to 'man5/proc_locks.5')
| -rw-r--r-- | man5/proc_locks.5 | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/man5/proc_locks.5 b/man5/proc_locks.5 new file mode 100644 index 0000000..c33ec82 --- /dev/null +++ b/man5/proc_locks.5 @@ -0,0 +1,122 @@ +.\" Copyright (C) 1994, 1995, Daniel Quinlan <quinlan@yggdrasil.com> +.\" Copyright (C) 2002-2008, 2017, Michael Kerrisk <mtk.manpages@gmail.com> +.\" Copyright (C) 2023, Alejandro Colomar <alx@kernel.org> +.\" +.\" SPDX-License-Identifier: GPL-3.0-or-later +.\" +.TH proc_locks 5 2023-11-19 "Linux man-pages 6.7" +.SH NAME +/proc/locks \- current file locks and leases +.SH DESCRIPTION +.TP +.I /proc/locks +This file shows current file locks +(\c +.BR flock (2) +and +.BR fcntl (2)) +and leases +(\c +.BR fcntl (2)). +.IP +An example of the content shown in this file is the following: +.IP +.in +4n +.EX +1: POSIX ADVISORY READ 5433 08:01:7864448 128 128 +2: FLOCK ADVISORY WRITE 2001 08:01:7864554 0 EOF +3: FLOCK ADVISORY WRITE 1568 00:2f:32388 0 EOF +4: POSIX ADVISORY WRITE 699 00:16:28457 0 EOF +5: POSIX ADVISORY WRITE 764 00:16:21448 0 0 +6: POSIX ADVISORY READ 3548 08:01:7867240 1 1 +7: POSIX ADVISORY READ 3548 08:01:7865567 1826 2335 +8: OFDLCK ADVISORY WRITE \-1 08:01:8713209 128 191 +.EE +.in +.IP +The fields shown in each line are as follows: +.RS +.IP [1] 5 +The ordinal position of the lock in the list. +.IP [2] +The lock type. +Values that may appear here include: +.RS +.TP +.B FLOCK +This is a BSD file lock created using +.BR flock (2). +.TP +.B OFDLCK +This is an open file description (OFD) lock created using +.BR fcntl (2). +.TP +.B POSIX +This is a POSIX byte-range lock created using +.BR fcntl (2). +.RE +.IP [3] +Among the strings that can appear here are the following: +.RS +.TP +.B ADVISORY +This is an advisory lock. +.TP +.B MANDATORY +This is a mandatory lock. +.RE +.IP [4] +The type of lock. +Values that can appear here are: +.RS +.TP +.B READ +This is a POSIX or OFD read lock, or a BSD shared lock. +.TP +.B WRITE +This is a POSIX or OFD write lock, or a BSD exclusive lock. +.RE +.IP [5] +The PID of the process that owns the lock. +.IP +Because OFD locks are not owned by a single process +(since multiple processes may have file descriptors that +refer to the same open file description), +the value \-1 is displayed in this field for OFD locks. +(Before Linux 4.14, +.\" commit 9d5b86ac13c573795525ecac6ed2db39ab23e2a8 +a bug meant that the PID of the process that +initially acquired the lock was displayed instead of the value \-1.) +.IP [6] +Three colon-separated subfields that identify the major and minor device +ID of the device containing the filesystem where the locked file resides, +followed by the inode number of the locked file. +.IP [7] +The byte offset of the first byte of the lock. +For BSD locks, this value is always 0. +.IP [8] +The byte offset of the last byte of the lock. +.B EOF +in this field means that the lock extends to the end of the file. +For BSD locks, the value shown is always +.IR EOF . +.RE +.IP +Since Linux 4.9, +.\" commit d67fd44f697dff293d7cdc29af929241b669affe +the list of locks shown in +.I /proc/locks +is filtered to show just the locks for the processes in the PID +namespace (see +.BR pid_namespaces (7)) +for which the +.I /proc +filesystem was mounted. +(In the initial PID namespace, +there is no filtering of the records shown in this file.) +.IP +The +.BR lslocks (8) +command provides a bit more information about each lock. +.SH SEE ALSO +.BR proc (5) |