Bug 24736

Summary:	Squashfs: Default compression method was changed from gzip to xz (lzma2), request to change it back to gzip
Product:	Mageia	Reporter:	Thomas Bigot <thomas.bigot>
Component:	RPM Packages	Assignee:	Thomas Backlund <tmb>
Status:	RESOLVED WONTFIX	QA Contact:
Severity:	normal
Priority:	Normal	CC:	marja11
Version:	Cauldron
Target Milestone:	---
Hardware:	All
OS:	Linux
Whiteboard:
Source RPM:	squashfs-tools-4.3-10.mga7.src.rpm	CVE:
Status comment:

Description Thomas Bigot 2019-04-29 16:57:28 CEST

Description of problem:
On Jan 25 2011, the default compression method was changed:
“build and use xz sypport by default”
in spec file: “COMP_DEFAULT=xz”

XZ is not available on old systems (CentOS 6 for instance). This change of default can cause strange behaviour like generating a squashfs volume not readable on some machines, only when the volume was produced on a Mageia system. Some programs like Singularity (https://github.com/sylabs/singularity) just use the default host system compression method and hence produce non widely distributable squashfs images.

Could the default compression method be restored as squashfs default one (gzip) ?

Comment 1 Marja Van Waes 2019-05-01 09:22:03 CEST

(In reply to Thomas Bigot from comment #0)
> Description of problem:
> On Jan 25 2011, the default compression method was changed:
> “build and use xz sypport by default”
> in spec file: “COMP_DEFAULT=xz”
> 
> XZ is not available on old systems (CentOS 6 for instance). 

CentOS 6 isn't even fully supported anymore, it only gets critical security updates and The CentOS team recommends moving workloads from CentOS Linux 6 to CentOS Linux 7. 

I'll assign this report to our squashfs-tools, though, for him to decide.

> This change of
> default can cause strange behaviour like generating a squashfs volume not
> readable on some machines, only when the volume was produced on a Mageia
> system. Some programs like Singularity
> (https://github.com/sylabs/singularity) just use the default host system
> compression method and hence produce non widely distributable squashfs
> images.
> 
> Could the default compression method be restored as squashfs default one
> (gzip) ?

Summary: Squashfs: Default compression method was changed from gzip to xz (lzma2) => Squashfs: Default compression method was changed from gzip to xz (lzma2), request to change it back to gzip
Assignee: bugsquad => tmb
CC: (none) => marja11

Comment 2 Thomas Backlund 2019-05-01 10:38:08 CEST

Yeah, sorry, but we wont reverse an 8+ year old change.

It would mean changing several things in the distro and buildsystem to start enforcing xz all over, so a lot of work for no real gain for us.

You should already be planning for moving to CentOS 7 (unless you are waiting for CentOS 8)

Or find a way to pass "-comp gzip" to your mksquashfs

Status: NEW => RESOLVED
Resolution: (none) => WONTFIX