Re: Mount Permissions (btrfs subvolumes)

[Greg Wooledge <greg@wooledge.org>]

On Sun, Jun 04, 2023 at 11:00:18PM -0400, ce wrote:
> On 6/4/23 5:46 PM, Greg Wooledge <greg@wooledge.org> wrote:
> > What kind of hardware is this file system on?
> >
> > What kind of file system is it?
> >
> > How did you mount it?  (Show the command you used, and any output that
> > it produced.)
> >
> > What does "mount" with no arguments say about the file system?  (Hint:
> > you can grep for the name of the file system.)
> >
> > What does the root level of the file system look like in "ls -la"?
> >
> > What did you EXPECT it to look like?
> 
> sid amd64 with btrfs
> 
> /etc/fstab:
> 
> ```
> LABEL=part2 /mnt/part2 btrfs compress=lzo 0 1
> ```
> 
> $ ls -l /mnt/part2
> ```
> drwxr-xr-x 1 me root 34 May 01 00:40 @subvolume
> ```
> 
> $ ls -l /mnt/part2/@subvolume
> 
> Some entries have user `me` but most entries have user `fuse`.
> 
> Idk what mount says it's mounted automatically.
> 
> chmod allows changing the group.
> 
> Let's see what a reboot does.

OK, thank you for the details.  Unfortunately, I know nothing about btrfs,
so I can't provide much help beyond this.  I can only address this part:

> Idk what mount says it's mounted automatically.

You can run the command "mount" with no arguments to see the details of
each mounted file system.  You don't even have to be root.  I don't know
how btrfs subvolumes work, so I don't know whether they appear in the
output of mount, but you could try it and see.