GNU bug report logs - #22768
Crash safety

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Message #44 received at 22768 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Antonio Diaz Diaz <antonio <at> gnu.org>, 22768 <at> debbugs.gnu.org
Cc: Yanyan Jiang <jiangyy <at> outlook.com>
Subject: Re: bug#22768: Crash safety
Date: Sun, 28 Feb 2016 00:26:58 -0800

[Message part 1 (text/plain, inline)]

Antonio Diaz Diaz wrote:

> ddrescue already provides the option '-y, --synchronous' for a somewhat
> similar functionality.

OK, let's do it as --synchronous, long-only.  If the need keeps growing we can 
add -y.

> Just now my preference is to make the behavior optional

On second thought, as Bob Proulx suggested, this is a better approach.  I tried 
the a synchronous gzip on a contrived example (compressing 1000 empty files on 
an ext4 file system on an actual hard drive with options relatime, seclabel, 
data=ordered) and synchronizing made gzip 700x slower.  Most people will prefer 
the old behavior, where gzip is faster and is unsafe mostly just in theory.

I'm attaching the patches I installed recently in this area, to help fix this 
problem.  I'll follow up on your other recent email in another message soon.

[0001-gzip-fdatasync-output-dir-before-unlinking.patch (text/x-diff, attachment)]

[0002-gzip-use-constants-not-fileno.patch (text/x-diff, attachment)]

[0003-gzip-new-option-synchronous.patch (text/x-diff, attachment)]

[0004-misc-update-version-copyright.patch (text/x-diff, attachment)]

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