Re: libsa and 4K devices

[mlelstv%serpens.de@localhost (Michael van Elst)]

nick.hudson%gmx.co.uk@localhost (Nick Hudson) writes:

>https://github.com/skrll/src/commit/a5432c0ce71ea2fd1b7ad22ff6c26d01f4dca7=
>1a


When looking at this, I got a few more issues:

- The copied filesystem code in libsa uses absolute disk offsets
  in bytes to locate superblocks. A backend that uses physical blocks
  cannot easily address such offsets if it doesn't know the block
  size.
  The filesystem code deduces this as fsize >> fsbtodb, but both
  values are only available after reading the superblock.

- fsck_msdos (used by arm64.img as the EFI partition is mounted)
  fails for large sectors. The bootblock (with disk info) is
  always read as 512 bytes.

- When testing in qemu, you can emulate a specific disk geometry
  including large sectors, but you cannot use a physical disk
  with large sectors as backend. Qemu will use I/O transfers
  as small as 512 bytes and it won't accept a block device.