Your message dated Sat, 10 Oct 2026 13:38:21 +0200
with message-id <[email protected]>
and subject line Fixed in 4.100
has caused the Debian Bug report #960358,
regarding exim4-base: spec.txt, NFS and file locking
to be marked as done.
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If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
960358: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=960358
Debian Bug Tracking System
Contact [email protected] with problems
--- Begin Message ---
Package: exim4-base
Version: 4.93-15
Severity: normal
In /usr/share/doc/exim4-base/spec.txt.gz :
--------
In order to append to an NFS file safely from more than one host, it is
necessary to take out a lock before opening the file, and the lock file
achieves this. Otherwise, even with fcntl() locking, there is a risk of file
corruption.
--------
I don't see why. If used correctly, fcntl() locking should be
sufficient under NFS. And if fcntl() locking is broken, lock files
won't prevent corruption anyway: even if you have the lock, there
is no guarantee that the client will synchronize the changes with
the server before another process gets the lock and do changes
(this is the problem I had with shared zsh history, which often
got corrupted even though zsh used some form of locking... until
I patched it in 2008 to use fcntl() locking).
-- Package-specific info:
Exim version 4.93 #5 built 25-Apr-2020 12:10:47
Copyright (c) University of Cambridge, 1995 - 2018
(c) The Exim Maintainers and contributors in ACKNOWLEDGMENTS file, 2007 - 2018
Berkeley DB: Berkeley DB 5.3.28: (September 9, 2013)
Support for: crypteq iconv() IPv6 GnuTLS move_frozen_messages DANE DKIM DNSSEC
Event I18N OCSP PRDR SOCKS TCP_Fast_Open
Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch cdb dbm dbmjz
dbmnz dnsdb dsearch nis nis0 passwd
Authenticators: cram_md5 plaintext
Routers: accept dnslookup ipliteral manualroute queryprogram redirect
Transports: appendfile/maildir/mailstore autoreply lmtp pipe smtp
Fixed never_users: 0
Configure owner: 0:0
Size of off_t: 8
Configuration file search path is
/etc/exim4/exim4.conf:/var/lib/exim4/config.autogenerated
Configuration file is /var/lib/exim4/config.autogenerated
-- System Information:
Debian Release: bullseye/sid
APT prefers unstable-debug
APT policy: (500, 'unstable-debug'), (500, 'stable-updates'), (500,
'unstable'), (500, 'testing'), (500, 'stable'), (1, 'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 5.4.0-4-amd64 (SMP w/12 CPU cores)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE,
TAINT_UNSIGNED_MODULE
Locale: LANG=POSIX, LC_CTYPE=C.UTF-8 (charmap=UTF-8), LANGUAGE=POSIX
(charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages exim4-base depends on:
ii adduser 3.118
ii anacron 2.3-29
ii cron [cron-daemon] 3.0pl1-136
ii debconf [debconf-2.0] 1.5.74
ii exim4-config [exim4-config-2] 4.93-15
ii libc6 2.30-4
ii libdb5.3 5.3.28+dfsg1-0.6
ii lsb-base 11.1.0
ii netbase 6.1
ii systemd-sysv 245-2
Versions of packages exim4-base recommends:
ii mailutils [mailx] 1:3.7-2.1
ii psmisc 23.3-1
Versions of packages exim4-base suggests:
ii emacs-gtk [mail-reader] 1:26.3+1-1
pn exim4-doc-html | exim4-doc-info <none>
pn eximon4 <none>
ii file 1:5.38-4
ii gnutls-bin 3.6.13-2
ii mailutils [mail-reader] 1:3.7-2.1
ii mutt [mail-reader] 1.13.2-1
ii openssl 1.1.1g-1
pn spf-tools-perl <none>
pn swaks <none>
-- debconf information excluded
--
Vincent Lefèvre <[email protected]> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
--- End Message ---
--- Begin Message ---
Version: 4.100-1
This was fixed in 4.100 with commit
1da9c193f2851ca19edf72ac626d133521586491
Docs: correct NFS file locking advice for appendfile (closes #3147)
The use_lockfile description claimed fcntl() locking risks file corruption
on NFS while a lock file prevents it. As pointed out in the exim-users
thread [1] and Debian #960358 [2], that is unfounded: if fcntl() over NFS
works, it is sufficient; if it does not, a lock file does not rescue the
situation either (client-side caching can still let stale writes reach
the server). Rewrite the paragraph and soften the matching "always use
lock files" advice in the file option description.
cu Andreas
--- End Message ---
