[cyphar]

This is something that reiserfs was trying to solve (though unfortunately we all know what happened with Hans and Nina Reiser), so most of the ideas have been left on the table.

But yeah, the solution he proposed was to start combining different information namespaces (such as the "metadata" namespace that you are alluding to) into the filesystem namespace, as well as allowing for the filesystem to be pluggable so people could write databases that could be searched with the filesystem.

So your example would look like

    for i in "$(ls)"; do echo $i/..../size; done

And you could do something like

    echo 1000 | tee */..../uid

Which would be equivalent to a chown.