Re: [9fans] Union mount directory behavior?

[Russ Cox <rsc@swtch.com>]

> term% ramfs -m /n/ram1
> term% ramfs -m /n/ram2
> term% bind /n/ram1 /n/ram
> term% bind -a /n/ram2 /n/ram
> term% mkdir /n/ram1/test
> term% mkdir /n/ram2/test
> term% touch /n/ram1/test/foo
> term% touch /n/ram2/test/bar
> term% ls -l /n/ram
> d-rwxrwxr-x M 47 nwf nwf 0 Jan 27 23:55 /n/ram/test
> d-rwxrwxr-x M 45 nwf nwf 0 Jan 27 23:55 /n/ram/test
> term% ls -l /n/ram/test
> --rw-rw-r-- M 45 nwf nwf 0 Jan 27 23:55 /n/ram/test/foo
> term% cat /n/ram/test/bar
> cat: can't open /n/ram/test/bar: '/n/ram/test/bar' does not exist
>
> Why don't I see /n/ram/test/bar?

Unions are not recursive.
You put two directories named test in /n/ram.
Because of the -a on the second bind, the one
from ram1 comes first.  When you cd into test,
you get the one from ram1.  That one only contains foo.

Russ