Attachment 909193 Details for Bug 1017478 – The upstream patch

The upstream patch

bz1017478.diff (text/plain), 1.93 KB, created by Steve Dickson on 2014-06-16 16:08:57 UTC

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Creator: Steve Dickson

Created: 2014-06-16 16:08:57 UTC

Size: 1.93 KB

patch

obsolete

>commit e449654fdb3f19aafc569df47d12bffdf6276236
>Author: Michael Kerrisk <mtk.manpages@gmail.com>
>Date:   Sun Apr 27 10:03:41 2014 +0200
>
>    flock.2: Add more details on NFS, including Linux 2.6.37 changes
>    
>    Also: move NOTES text describing interaction of fcntl()
>    and flock() locks.
>    
>    Reviewed-by: NeilBrown <neilb@suse.de>
>    Reported-by: NeilBrown <neilb@suse.de>
>    Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
>
>diff --git a/man2/flock.2 b/man2/flock.2
>index 324f37d..e7c9c3d 100644
>--- a/man2/flock.2
>+++ b/man2/flock.2
>@@ -32,7 +32,7 @@
> .\" FIXME: Maybe document LOCK_MAND, LOCK_RW, LOCK_READ, LOCK_WRITE
> .\"        which only have effect for SAMBA.
> .\"
>-.TH FLOCK 2 2014-04-22 "Linux" "Linux Programmer's Manual"
>+.TH FLOCK 2 2014-04-27 "Linux" "Linux Programmer's Manual"
> .SH NAME
> flock \- apply or remove an advisory lock on an open file
> .SH SYNOPSIS
>@@ -146,12 +146,36 @@ possibly implemented in terms of
> .BR fcntl (2),
> appears on most UNIX systems.
> .SH NOTES
>+In Linux kernels up to 2.6.11,
> .BR flock ()
>-does not lock files over NFS.
>-Use
>+does not lock files over NFS
>+(i.e., the scope of locks was limited to the local system).
>+Instead, one could use
> .BR fcntl (2)
>-instead: that does work over NFS, given a sufficiently recent version of
>+byte-range locking, which does work over NFS,
>+given a sufficiently recent version of
> Linux and a server which supports locking.
>+Since Linux 2.6.12, NFS clients support
>+.BR flock ()
>+locks by emulating them as byte-range locks on the entire file.
>+This means that
>+.BR fcntl (2)
>+and
>+.BR flock ()
>+locks
>+.I do
>+interact with one another over NFS.
>+Since Linux 2.6.37,
>+.\" commit 5eebde23223aeb0ad2d9e3be6590ff8bbfab0fc2
>+the kernel supports a compatibility mode that allows
>+.BR flock ()
>+locks (and also
>+.BR fcntl (2)
>+byte region locks) to be treated as local;
>+see the discussion of the
>+.I "local_lock"
>+option in
>+.BR nfs (5).
> .PP
> Since kernel 2.0,
> .BR flock ()

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