[0/1] Enforce 4k sectorize by default for mkfs

Message

Neal Gompa March 22, 2023, 10:17 p.m. UTC

The Fedora Asahi SIG[0] is working on bringing up support for
Apple Silicon Macintosh computers through the Asahi Fedora 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.

Soon, this will be even more of a problem within Apple Silicon Macs
as Asahi Lina is working on 4k support to enable x86 emulation[2]
and since Linux does not support dynamically switching page sizes at
runtime, users will likely regularly switch back and forth depending
on their needs.

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
looks promising[4], and I hope we can get this to land upstream soon.

=== Changelog ===

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://asahi-fedora-remix.org/
[2]: https://vt.social/@lina/110060963422545117
[3]: https://lore.kernel.org/linux-btrfs/[e-mail]/T/#m11d7939de96c43b3a7cdabc7c568d8bcafc7ca83
[4]: https://lore.kernel.org/linux-btrfs/[e-mail]/T/#mf382b78a8122b0cb82147a536c85b6a9098a2895

Neal Gompa (1):
  btrfs-progs: mkfs: Enforce 4k sectorsize by default

 Documentation/Subpage.rst    | 15 ++++++++-------
 Documentation/mkfs.btrfs.rst | 13 +++++++++----
 mkfs/main.c                  |  2 +-
 3 files changed, 18 insertions(+), 12 deletions(-)