How do I tell what's loading all these snap filesystems?

[Colin Watson]

On Sat, Dec 07, 2019 at 03:07:33PM +0000, Chris Green wrote:
> I know this pulls in chromium as a snap package and that there's no
> alternative but there seem to be quite a lot of snap filesystems on my
> system now.  Are *all* of these a consequence of chromium or is
> something else using snap that I don't know about?  How can one find
> out what's using a snap filesystem?

All the ones you list are a consequence of chromium, yes.  Note that you
can use "df -x squashfs" if you just want less noise in df output.

>     /dev/loop0            55     55         0 100% /snap/core18/1265
>     /dev/loop1            45     45         0 100% /snap/gtk-common-themes/1353
>     /dev/loop2           154    154         0 100% /snap/chromium/958
>     /dev/loop3            23     23         0 100% /snap/snapd/5306
[...]
>     /dev/loop4            55     55         0 100% /snap/core18/1279
>     /dev/loop5            23     23         0 100% /snap/snapd/5643
> 
> So, obviously, chromium accounts for /snap/chromium/958 and the snap
> daemon accounts for /snap/snapd/5306 (but why is there also
> /snap/snapd/5643?).

snapd keeps some old versions around so that "snap revert" can work.

> However what's using those other /snap filesystems, two of them with
> core18 in the name and /snap/gtk-common-themes/1353?  Is there any way
> of finding out, from the filesystem name, what package/software is
> creating them?

chromium is built with the core18 snap as its base, and connects to
gtk-common-themes.  "snap info --verbose chromium" will show you "base:
core18" among its output, and you should see gtk-common-themes mentioned
in the output of "snap connections".

-- 
Colin Watson                                       [cjwatson at ubuntu.com]