Re: [PATCH 0/2] btrfs: port to new mount api

[David Sterba <dsterba@suse.cz>]

On Tue, Jun 27, 2023 at 11:51:01AM +0000, Johannes Thumshirn wrote:
> On 26.06.23 16:19, Christian Brauner wrote:
> > This whole thing ends up being close to a rewrite in some places. I
> > haven't found a really elegant way to split this into smaller chunks.
> 
> You'll probably hate me for this, but you could split it up a bit by 
> first doing the move of the old mount code into params.c and then do the
> rewrite for the new mount API.

The patch needs more finer split than just that. Replacing the entire
mount code like that will introduce bugs that users will hit for sure.
We have some weird mount option combinations or constraints, and we
don't have a 100% testsuite coverage.

The switch to the new API needs to be done in one patch, that's obvious,
however all the code does not need to be in one patch. I suggest to
split generic preparatory changes, add basic framework for the new API,
then add the easy options, then by one the complicated ones, then do the
switch, then do the cleanup and removal of the old code. Yes it's more
work but if we have to debug anything in the future it'll be narrowed
down to a few short patches.

Previsous work (https://lore.kernel.org/linux-btrfs/20200812163654.17080-1-marcos@mpdesouza.com/)
has patches split but it's not following the suggestions.