Re: [PATCH v4 0/1] Enforce 4k sectorize by default for mkfs

From: David Sterba <dsterba@suse.cz>
To: Neal Gompa <neal@gompa.dev>
Cc: Linux BTRFS Development <linux-btrfs@vger.kernel.org>,
	Anand Jain <anand.jain@oracle.com>,
	Qu Wenruo <quwenruo.btrfs@gmx.com>, Qu Wenruo <wqu@suse.com>,
	David Sterba <dsterba@suse.cz>, Hector Martin <marcan@marcan.st>,
	Sven Peter <sven@svenpeter.dev>,
	Davide Cavalca <davide@cavalca.name>, Jens Axboe <axboe@fb.com>,
	Asahi Lina <lina@asahilina.net>,
	Asahi Linux <asahi@lists.linux.dev>
Subject: Re: [PATCH v4 0/1] Enforce 4k sectorize by default for mkfs
Date: Wed, 13 Dec 2023 23:25:29 +0100	[thread overview]
Message-ID: <20231213222529.GF3001@twin.jikos.cz> (raw)
In-Reply-To: <20231116160235.2708131-1-neal@gompa.dev>

On Thu, Nov 16, 2023 at 11:02:23AM -0500, Neal Gompa wrote:
> The Fedora Asahi SIG[0] is working on bringing up support for
> Apple Silicon Macintosh computers through the Fedora Asahi Remix[1].
> 
> Apple Silicon Macs are unusual in that they currently require 16k
> page sizes, which means that the current default for mkfs.btrfs(8)
> makes a filesystem that is unreadable on x86 PCs and most other ARM
> PCs.
> 
> This is now even more of a problem within Apple Silicon Macs as it is now
> possible to nest 4K Fedora Linux VMs on 16K Fedora Asahi Remix machines to
> enable performant x86 emulation[2] and the host storage needs to be compatible
> for both environments.
> 
> Thus, I'd like to see us finally make the switchover to 4k sectorsize
> for new filesystems by default, regardless of page size.
> 
> The initial test run by Hector Martin[3] at request of Qu Wenruo
> looked promising[4], and we've been running with this behavior on
> Fedora Linux since Fedora Linux 36 (at around 6.2) with no issues.
> 
> === Changelog ===
> 
> v4: Fixed minor errors in the cover letter and patch subject
> 
> v3: Refreshed cover letter, rebased to latest, updated doc references for v6.7
> 
> v2: Rebased to latest, updated doc references for v6.6
> 
> Final v1: Collected Reviewed-by tags for inclusion.
> 
> RFC v2: Addressed documentation feedback
> 
> RFC v1: Initial submission
> 
> [0]: https://fedoraproject.org/wiki/SIGs/Asahi
> [1]: https://fedora-asahi-remix.org/
> [2]: https://sinrega.org/2023-10-06-using-microvms-for-gaming-on-fedora-asahi/
> [3]: https://lore.kernel.org/linux-btrfs/fdffeecd-964f-0c69-f869-eb9ceca20263@suse.com/T/#m11d7939de96c43b3a7cdabc7c568d8bcafc7ca83
> [4]: https://lore.kernel.org/linux-btrfs/fdffeecd-964f-0c69-f869-eb9ceca20263@suse.com/T/#mf382b78a8122b0cb82147a536c85b6a9098a2895
> 
> Neal Gompa (1):
>   btrfs-progs: mkfs: Enforce 4k sectorsize by default

FYI, current plan is to add the change to 6.7 release with ETA in
January. We've discussed this and given the increasing demand for that
from various distros and testing coverage so done far it seems that it's
sufficient.