On 13/06/2025 at 19:21, Pascal Hambourg wrote:
/etc/mke2fs.conf from e2fsprogs sets the default block size to 4096, so ext* filesystems created with the default block size are safe with 4k page size. However it sets blocksize = -1 for filesystems created with "largefile" or "largefile4" usage (-T). These usages can be selected in the installer. Back to mke2fs(8) man page:If omitted, block-size is heuristically determined by the file system size and the expected usage of the file system (see the -T option). In most common cases, the default block size is 4k. If block-size is preceded by a negative sign ('-'), then mke2fs will use heuristics to determine the appropriate block size, with the constraint that the block size will be at least block-size bytes.I have no details nor experience about mke2fs heuristics, but from the above a block size above 4k might be chosen under specific conditions when the page size is 64k. Maybe someone can shed some light here and advise if the same check as btrfs should be suggested.
It was confirmed in #1106757 [1] that specifying "largefile" or "largefile4" usage type results in 64k block size with bookworm ppc64el kernel (64k page size), and this is not supported by trixie ppc64el default kernel (4k page size).
[1] <https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1106757#105>
