mkfs.bcachefs defaults to block size 512 for a device with block size 512

[myxoid]

Public documentation says the block size defaults to 4096.

bcachefs-tools built at b34d1341919c4edd3251c7f69c2588acd1196d71

I used mkfs.bcachefs rather than bcachefs format, but from reading the code, that should make no difference.

The man page does list defaults for a few things, but not the block size.

---

Looking at the code, this line:

opt_set(fs_opts, block_size, max_dev_block_size);

could be replaced with:

opt_set(fs_opts, block_size, max(4096, max_dev_block_size));

Or the documentation could be adjusted to say "block_size (default: maximum of all supplied device blocks sizes)".

---

It would be nice to a have stub man pages for the mkfs.* commands explaining that they are equivalent to ...

---

Total pedantry: Unless you are checking that all block sizes are powers of two, you should be calculating LCM instead of max, initialising lcm_dev_block_size to 1, not 0, and checking that the user-supplied block size % LCM block size is zero.