[zrm]

You expect the files to still be accessible using relative paths. What do you expect to happen if your cloud storage file path is 50 characters long and is mounted in a folder which is 4050 characters long when PATH_MAX is 4096?

The sync application itself can handle this using openat(2) or similar and should probably be using that regardless to avoid races.

[dns_snek]

Ah, I forgot that the maximum path length is usually limited by PATH_MAX, it's the path segment that's usually limited by the filesystem.

Point taken, although I still think it's better for cloud storage services to err on the side of compatibility, i.e. what's the lowest common denominator between Linux, macOS, Android, iOS from 10 years ago and Windows 7?