Re: [PATCH v2 00/22] Fix error handling during bitmap postcopy

[Eric Blake <eblake@redhat.com>]

On 2/19/20 7:36 AM, Eric Blake wrote:

>> +od: unrecognized option '--endian=big'
>> +Try 'od --help' for more information.
>> +od: invalid -N argument '--endian=big'
>> +qemu-img: Could not open 'TEST_DIR/t.IMGFMT': IMGFMT header exceeds 
>> cluster size
> 
> Which version of od are you using?  I do recall wondering whether 
> reliance on the GNU coreutils extension --endian=big was going to cause 
> problems later - well, here we are, it's later :)
> 
> https://lists.gnu.org/archive/html/qemu-devel/2019-07/msg06781.html

coreutils documents that od --endian was added in 8.23, released in 
2014-07-18.  Per https://wiki.qemu.org/Supported_Build_Platforms, we 
still have support for RHEL 7 through 2022, and it was first released 
2014-06-09 (all other supported distros have newer releases, but I 
didn't check what coreutils version they included, or even if the BSD 
builds which don't use coreutils would also be impacted by this 
problem).  Still, I'd like to know your specific setup, and why the CI 
tools have not flagged it.

But even one counterexample within the bounds of our supported distro 
page is a good argument that use of od --endian is not yet portable. 
Or, if your setup is not on the supported page, it becomes a question of 
whether it should be added or whether you should upgrade to something 
that is supported.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org