GNU bug report logs - #79139
cp --reflink truncates sparse files on ZFS

Previous Next

Full log

Message #46 received at 79139 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Pádraig Brady <P <at> draigBrady.com>
Cc: 79139 <at> debbugs.gnu.org, bug-gnulib <at> gnu.org, Leah Neukirchen <leah <at> vuxu.org>
Subject: Re: bug#79139: cp --reflink truncates sparse files on ZFS
Date: Sat, 2 Aug 2025 09:03:38 -0700

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

On 2025-08-02 01:32, Pádraig Brady wrote:

> it's worth mentioning run-time vs build-time checks. 

Yes, and this could be documented more. I installed the attached.

> For reference I made some notes on various version compat at:
> http://pixelbeat/programming/linux_binary_compatibility.html

I needed to use this URL:

https://www.pixelbeat.org/programming/linux_binary_compatibility.html

> the gnulib workaround isn't too onerous as SYS_BUFZISE_MAX is large,
> and I expect the glibc fix will be backported to glibc 2.41 systems 
> promptly anyway.

Yes, I went through similar thought processes. It didn't seem worth the 
hassle to do the extra glibc runtime checks. Gnulib has always used 
static checks for glibc versions, even in areas where this is serious 
business (e.g., malloc misbehavior). So far, nobody has reported an 
issue for this. Maybe people who build for older kernels (which is 
dubious if you ask me) aren't building for older glibcs (which is even 
more dubious).

[0001-More-copy_file_range-commentary.patch (text/x-patch, attachment)]

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.