Re: Bug#921146: Program mksquashfs from squashfs-tools 1:4.3-11 does not make use all CPU cores

[Phillip Lougher]

On Fri, Aug 2, 2019 at 1:35 AM Theodore Y. Ts'o <tytso@xxxxxxx> wrote:
>
> Phillip,
>

Hi Theodore (Ted),

Thank-you for your kind and well intentioned email.  It has
de-escalated tensions on my side.

It is very late here, and so I can only be brief, but, I want this
said as soon as possible.

> Peace.

Yes, I would very much like that to happen.

>
> You may not like the fact that David Oberhollenzer (GitHub username
> AgentD) started an effort to implement a new set of tools to generate
> squashfs images on April 30th, 2019, and called it squashfs-tools-ng.
>
> However, it's really not fair to complain that there is a "violation
> of copyright" given that all of squashfs-tools was released is under
> the GPL.  Using some text from squashfs-tools in the package
> description or documentation of squashfs-tools-ng is totally allowed
> under the GPL.  You could complain that they didn't include an
> acknowledgement that text was taken from your program.  But then give
> them time to fix up the acknowledgements.  Assuming good faith is
> always a good default.
>
> The other thing that you've complained about is that some folks have
> (inaccurately, in your view) described squashfs-tools as not being
> maintained.  I'd encourage you to take a step back, and consider how
> this might be quite understandable how they might have gotten that
> impression.
>
> First of all, let's look on the documentation in kernel source tree,
> located at Documentation/filesystems/squashfs.txt.  It states that
> squashfs-tools's web site is www.squashfs.org, and the git tree is at
> git://git.kernel.org/pub/scm/fs/squashfs/squashfs-tools.git.
>
> The web site www.squashfs.org is not currently responding, but
> according to the Internet Archive, it was redirecting to
> http://squashfs.sourceforge.net/.  This web site describes the latest
> version of squashfs-tools is 4.2, released in February 2011, It
> apparently wasn't updated when squashfs-tools 4.3 was released in May
> 2014.
>

I gave up on Sourceforge many years ago when it came unusable (in my
opinion) due to too many adverts.

If I knew how to remove Squashfs from Sourceforge to save confusion I
would have done so.

> The git.kernel.org tree is identical to the sourceforge.net's git
> tree.  That tree's most recent commit is from August 2017, e38956b9
> ("squashfs-tools: Add zstd support").  Now, the fascinating thing is
> that the github tree has a completely different commit-id for the same
> commit is 61133613 ("squashfs-tools: Add zstd support").  The git
> commit that the two trees have in common is 9c1db6d1 from September
> 2014.
>
> Reconstructing the git history, you didn't make any commits between
> September 2014 and March 2017.  At that time, you merged a number of
> github pull requests between 2014 and 2017, but then exported them as
> patches and applied them on the kernel.org/sourceforge git trees.
> Why, I'm not sure.
>

I clicked the web merge button on GitHub, and then ended up with the
patches in the GitHUb repository (which I didn't use at the time), and
synced manually with kernel.org/sourceforge.

Blame lack of knowledge of GitHub. on my behalf.  I tend to prefer
command-interfaces which can be scripted.

> In August 2017, you stopped updating the kernel.org and sourceforge
> git trees, and abandoned them.  After that for the rest of 2017, you
> merged one more pull request, and applied one commit to add the -nold
> option.  In 2018, there were only two commits, in February and June.
> And then nothing until April 2019 (about the time that squash-tools-ng
> was started/announced), there has been a flurry of activity, including
> merging github pull requests from 2017 and 2018, antd you've done a
> lot of work since then.
>

The start of development in April and the co-incidence with the
squashfs-tools-ng project is purely coincidental.   I didn't know
anything about squashfs-tools-ng until Matt Turner of Gentoo mentioned
it in an issue on GitHub
(https://github.com/plougher/squashfs-tools/issues/25) nine days ago.

I didn't know about this co-incidence until you pointed it out.  This
in fact may explain some of the mis-understanding.

I meant to do some development on Squashfs-tools over the last
Christmas vacation.  I don't want to go into private family details.
but two deaths and a stroke in the family meant I had more important
things to deal with.  April was then the first opportunity I got to do
some development.

I try to keep people up to date with my intentions and commitments,
and I mentioned all this in another issue on GitHub
(https://github.com/plougher/squashfs-tools/issues/54).

> I say this not to criticize the amount of attention you've paid to
> squashfs-tools, but to point out that when David started work on
> squashfs-tools-ng, it's not unreasonable that he might have gotten the
> impression that development had ceased --- especially if he followed
> the documentation in the kernel sources, and found an extremely
> cobwebby website, and a git tree on git.kernel.org that hadn't been
> updated since 2017, with substantive heavy development basically
> ending in 2014 (which is also when the last release of squashfs-tools
> was cut).

In 2012-2014 I was put into a difficult position.  The previous year I
had started work @ Redhat as a kernel maintainer, which was leaving me
very little free time.

But the tools (especially Mksquashfs) which I had written in my spare
time between 2002-2009, when Squashfs was purely a hobbyist
filesystem, were increasingly breaking.  There were issues with stack
size, overflows, and basically dozens of things which fuzzers and
others like to exploit to produce crashes etc.

I decided I had to do a major rewrite of Mksquashfs.  It took over two
years, working all evenings available (from work) and most weekends
and at the end of it I felt completely burnt out.  My intention was
this should give me space to concentrate on other things for a while,
having cleared up all the issues.

I went on vacation a couple of months after release, deliberately
where there was no internet (off grid).  When I came back I found a
number of highly abusive emails from people, that had gotten more
abusive as I'd not answered them for a week.  I then had what I now
recognise to be a nervous breakdown.  I destroyed all my development
files and notes, and I couldn't bear to look at a line of Squashfs
code for a couple of months.

I obviously came back after a couple of months.  But, I took the
decision to not let Squashfs become the nightmare it had been for a
couple of years.  I would step back and cease to do pro-active
development and concentrate on security issues, bug fixes and
correspondence.

I genuinely felt things were going well and I was getting a good
balance between my life, my job, and Squashfs, until now.

Perhaps that is why I have reacted "so badly" now, it is called dismay.

I can't write anymore as it is already very late.

Best Regards

Phillip



> You don't need to ascribe malice to what might just simply
> be an impression by looking in the official locations in the official
> kernel documentation!
>
> As a fellow kernel file system developer, let me make a few
> suggestions.
>
> * Don't worry about with "competing" software projects.  For a while,
>   a multi-billion dollar company attempted to maintain a BSD-licensed
>   "competition" to some of the programs in e2fsprogs.  This was
>   because Andy Rubin was highly allergic to the GPL way back when.  I
>   pointed the independent implementation was creating invalid file
>   systems, and was buggy, and in general was making that billion
>   dollar company's life harder, not easier.  They eventually gave up
>   on it, and Android uses e2fsprogs these days.
>
>   The whole point of open source is "may the best code win".  If
>   you're convinced that you, as the upstream kernel developer, can do
>   a better job maintaining the userspace tools, then instead of
>   complaining and threatening to sue, just keep your head down, and
>   keep improving your code, and in the end, the best code will win.
>
> * I'd suggest that you make sure there is a single canonical git tree.
>   It appears it's the github version of your git tree.  So... starting
>   with your github tree, do a "git merge" of the master branch from
>   git.kernel.org, and then push updates to github, git.kernel.org, and
>   git.sf.code.net.  It's fine to have multiple mirrors of your git
>   tree.  I maintain multiple copies of git e2fsprogs repo on
>   git.kernel.org, github, and sourceforge.
>
> * Please consider tagging your releases.  There are git tags for
>   squashfs 3.1 and 3.2, but none of your 4.x releases.  It's going to
>   make it much easier for other people to know which git commits
>   correspond to your official releases.  For bonus points, you could
>   use signed git tags.  If you need help getting that set up, please
>   contact me off-line.  I'd be delighted to help you with that.
>
> * Please consider updating the squashfs web site.  I acutally keep a
>   copy of the e2fsprogs.sourceforge.net web site in the e2fsprogs git
>   tree, under the "web" branch.  You can see it here:
>   https://github.com/tytso/e2fsprogs/tree/web
>
> * It can be handy to audit and apply/merge patches being carried by
>   distributions.  Before I took over the Debian maintainership of
>   e2fsprogs, I would periodically scan the debian patches (and I still
>   keep an eye to see what Ubuntu and Fedora have in their local
>   patches).  If any of those patches fix real bugs, I'll pull them
>   into the e2fsprogs git repo, and then send a note to the
>   distribution maintainer that I've done so, and let them know that in
>   the next release, I've included their patch, and so they can drop it
>   from their tree.  That way, I can find and fix bugs introduced by
>   distribution patches.
>
> In general, I've found that keeping on good terms with the
> distribution packagers is really good thing from the perspective of
> the upstream author.
>
> Best regards,
>
>                                                 - Ted
>