linux-kernel - Re: [PATCH] add support for larger files in minix filesystem

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Message-ID: <20160109033712.GA5955@ZenIV.linux.org.uk>
Date:	Sat, 9 Jan 2016 03:37:12 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Joshua Hudson <joshudson@...il.com>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] add support for larger files in minix filesystem

On Sun, Nov 01, 2015 at 07:56:36PM -0800, Joshua Hudson wrote:
> From: Joshua Hudson <joshudson@...il.com>
> 
> The Minix v3 filesystem and kernel driver have no actual dependency on files
> being less than 2GB in size; however the kernel does not allow creating a
> file of 2GB or larger on a Minix v3 filesystem. I was able to remove the pseudo-
> dependency easily by changing one line of code (filesystems need to tell VFS
> how big of files they allow).

Umm...  AFAICS, native Minix v3 fsck will throw a fit if it sees anything
between 2Gb and 4Gb and truncate the value.  Seeing that it's their
format _and_ silent changes like that (especially hidden by something like
"you need to binary-patch the field at this offset in superblock first")
are generally considered rude.

I'd suggest you to talk to Minix folks and convince them to raise that limit;
if it's merely a matter of unhappy fsck, it shouldn't be hard, but if their
minix/mfs/*.c code would get unhappy on files longer than 2Gb, it would be
harder and in that case we _really_ shouldn't run around creating such files
there.

Seriously, talk to Minix folks first.