Should we support inter-process file locking?

[sbc100]

Right now we simply stub out calls like flock and fcntl+F_SETLK.

At least for the OPFS wasmfs backend it seems like it could be usefull?

I assume that the OPFS filesystem can be shared between multiple running emscripten programs? (or the same program running in multiple tabs?)

Are there any other FS backends that could benefit?

[brandonpayton]

This is something we are exploring with WordPress Playground for use with NODEFS (currently with the legacy FS).

I prototyped an async override for fcntl() to support F_GETLK and F_SETLK so multiple manually-created php-wasm workers could share a SQLite DB file without corruption.

[adamziel]

To close the loop, @brandonpayton implemented fcntl() for WordPress Playground's PHP.wasm in https://github.com/WordPress/wordpress-playground/pull/2231