From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 References: <20180627012421.80B8F24E094@nmr-admin> <3681004.ZGfTzPZDUK@merkaba> <102c5f41-7fa8-267c-973a-176d3c3d4f57@gmail.com> In-Reply-To: <102c5f41-7fa8-267c-973a-176d3c3d4f57@gmail.com> From: Geert Uytterhoeven Date: Fri, 29 Jun 2018 10:51:12 +0200 Message-ID: Subject: Re: Subject: [PATCH RFC] block: fix Amiga RDB partition support for disks >= 2 TB To: Michael Schmitz Cc: Martin Steigerwald , Jens Axboe , jdow , linux-m68k , linux-block@vger.kernel.org Content-Type: text/plain; charset="UTF-8" List-ID: Hi Michael, On Fri, Jun 29, 2018 at 10:43 AM Michael Schmitz wrote: > Am 28.06.18 um 21:25 schrieb Geert Uytterhoeven: > >>> Do we really need the warning? > >>> Once the parsing is fixed doing 64-bit math, it does not matter for > >>> Linux anymore. > >> Well, irony of this is: In my case the RDB has been created on a machine > >> with a native OS. So Linux warns me about something I already did so on > >> the native OS without any warning. In this case AmigaOS 4.0. > > Exactly. > > > > So moving a disk partitioned under AmigaOS 4.0 to a system running an > > older version of AmigaOS can fail miserably. Not a Linux issue. > > Linux also doesn't warn about disks with GPT failing to work on old MSDOS. > > Would MSDOS recognize the GPT partition as 'probably FAT', and attempt > to use it? No idea... Probably some old Windows or MacOS versions will just suggest to format your "new" disk ;-) But it's up to the person (which is not Linux) formatting the disk to not try to use it on systems that cannot handle it, and may destroy it. > > Let me clarify: what exactly would the kernel option allow? When to use it? > > Whether to use it if safe (on Linux). But whatever Linux does (after > this patch), access will go to the right area of the disk (as specified > by the RDB) so Linux won't any longer stomp on anything that would have > mattered to 32 bit disk drivers. So it really should be safe. Personally, I see no reason to depend on a kernel option, if it is safe to use. Just use it. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds