File util-linux-flock-limitations.patch of Package util-linux
From f4d9018183ff9a6cd6a77bf33461b60570ec7622 Mon Sep 17 00:00:00 2001 From: Stanislav Brabec <sbrabec@suse.cz> Date: Fri, 25 Mar 2022 09:26:48 +0100 Subject: flock: Decribe limitations of flock: deadlock, NFS, CIFS The flock(1) does not refer to limitations of flock(2). Provide an documentation entry point for solving of problems with flock on NFS and CIFS and mention risk of deadlock. Signed-off-by: Stanislav Brabec <sbrabec@suse.cz> Signed-off-by: Karel Zak <kzak@redhat.com> --- sys-utils/flock.1.adoc | 6 ++++++ 1 file changed, 6 insertions(+) Index: util-linux-2.37.4/sys-utils/flock.1.adoc =================================================================== --- util-linux-2.37.4.orig/sys-utils/flock.1.adoc +++ util-linux-2.37.4/sys-utils/flock.1.adoc @@ -95,6 +95,12 @@ The command uses <sysexits.h> exit statu When using the _command_ variant, and executing the child worked, then the exit status is that of the child command. +== NOTES + +*flock* does not detect deadlock. See *flock*(2) for details. + +Some file systems (e. g. NFS and CIFS) have a limited implementation of *flock*(2) and flock may always fail. For details see *flock*(2), *nfs*(5) and *mount.cifs*(8). Depending on mount options, flock can always fail there. + == EXAMPLES Note that "shell> " in examples is a command line prompt. Index: util-linux-2.37.4/sys-utils/flock.1 =================================================================== --- util-linux-2.37.4.orig/sys-utils/flock.1 +++ util-linux-2.37.4/sys-utils/flock.1 @@ -109,6 +109,11 @@ Display help text and exit. The command uses <sysexits.h> exit status values for everything, except when using either of the options \fB\-n\fP or \fB\-w\fP which report a failure to acquire the lock with an exit status given by the \fB\-E\fP option, or 1 by default. The exit status given by \fB\-E\fP has to be in the range of 0 to 255. .sp When using the \fIcommand\fP variant, and executing the child worked, then the exit status is that of the child command. +.SH "NOTES" +.sp +\fBflock\fP does not detect deadlock. See \fBflock\fP(2) for details. +.sp +Some file systems (e. g. NFS and CIFS) have a limited implementation of \fBflock\fP(2) and flock may always fail. For details see \fBflock\fP(2), \fBnfs\fP(5) and \fBmount.cifs\fP(8). Depending on mount options, flock can always fail there. .SH "EXAMPLES" .sp Note that "shell> " in examples is a command line prompt.
