[exim-dev] Re: [Bug 2834] Directories not removed after av_s…

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Συντάκτης: Andrew C Aitchison
Ημερομηνία:  
Προς: Exim Bugzilla
Υ/ο: exim-dev
Αντικείμενο: [exim-dev] Re: [Bug 2834] Directories not removed after av_scan
On Fri, 20 Oct 2023, Exim Bugzilla via Exim-dev wrote:

> https://bugs.exim.org/show_bug.cgi?id=2834
>
> --- Comment #10 from Piotr Staszeski <tech@???> ---
> Last update
> The issue still exists in newest version 4.96.2. We were mange to investigate
> it deeper and it turned out that the issue is related with 'silly renamed'
> mechanism in NFS.
>
> Long story short, we were monitoring the spool directory using:
> while :; do date; DIR=`date +%s%N`; find /opt/smtp_data/data/spool/scan/ -type
> f -exec mkdir copy/${DIR} ';' -exec cp -v '{}' copy/${DIR} ';'; usleep 100;
> done


Am I right in thinking that you are running this on the client,
not the file-server ?
If the spool and the copy are on the same file-system,
does a hard-link `ln` instead of the `cp -v` give you new information ?
It should also be quicker.

Can you run fuser (or perhaps fuser -v) in the monitor script, just to
confirm that it is exim (and not the scanner) holding the files open ?


> and here is the output:
>
> Wed Oct 18 14:22:05 CEST 2023
> ‘/opt/smtp_data/data/spool/scan/1qt5Yr-00074v-3g/1qt5Yr-00074v-3g.eml’ ->
> ‘copy/1697631725208102956/1qt5Yr-00074v-3g.eml’
> Wed Oct 18 14:22:05 CEST 2023
> ‘/opt/smtp_data/data/spool/scan/1qt5Yr-00074v-3g/.nfs00000000000200b300000016’
> -> ‘copy/1697631725238316816/.nfs00000000000200b300000016’


> Wed Oct 18 14:22:05 CEST 2023
> ‘/opt/smtp_data/data/spool/scan/1qt5Yr-00074v-3g/.nfs00000000000200b300000016’
> -> ‘copy/1697631725446052356/.nfs00000000000200b300000016’
> Wed Oct 18 14:22:05 CEST 2023
>
> For test purpose, we've tried to add sleep 2sec (in spool_mbox.c) after removed
> mail, but before removing directory itself.. but without any success. So. the
> question is why this issue is not present in 4.94.2 ? And how we can fix it, to
> be able to using nfs as a storage ?


I take it you have a good reason to use a (remote) NFS file system
for what is working storage ? I have known people who put the spool
on battery-backed RAM rather than have the delay of spinning rust here.
Of course if your scan happens on another machine you *may* have no
choice.

Of course, this does not explain why something changed after 4.94.2.

----
A quick google for ".nfs files" tells me

http://nfs.sourceforge.net/#faq_d2

NFSv4.1 will get away from this behavior with 
OPEN4_RESULT_PRESERVE_UNLINKED:

http://tools.ietf.org/html/rfc5661#section-18.16.

- is NFS v4.1 an option ?

-- 
Andrew C. Aitchison                      Kendal, UK
                    andrew@???


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