On Mon, 2011-09-05 at 16:43 +0200, Björn Kalkbrenner wrote:
> Hi Ilya,
>
> Am 05.09.2011 15:07, schrieb Ilya Dryomov:
> > Well, it's *sort of* expected if you think about it. When you mounted
> > after set-default, your /home is no longer a valid subvolume access
> > point (it was in the default subvolume, until you rebooted). Inside
> > your snapshot /home is just an empty directory (there's more to it,
> > that's why you can't delete it, but that's irrelevant here). However
> > if you mount with subvolid=<objectid>, you point to a subvolume
> > directly, skipping the lookup (which leads to an empty dir if you are
> > inside your snapshot). That's why it works when you use the subvolid.
> > We should probably tune the lookup to make subvol= work in this case.
>
> Ah, thank you very much, that sounds logical with the lookup table and
> the - not valid access point - BUT:
>
> Why could i still manually "mount -o subvol=home /dev/mapper/root /home"
> and home was just empty but mounted (i looked at the mount table output)?
> Shouldn't that give me an error that home can't be found in the lookup
> table?
This is actually because of how the subvolume mounting works internally.
It turns out that currently, the command
mount -o subvol=home /dev/mapper/root /home
effectively does the same thing as
mount /dev/mapper/root /home # Mount the "default" subvolume
mount --bind /home/home /home # Switch to the "home" subvolume
which of course succeeds if /home in your default subvolume is an empty
directory.
Hopefully this can be improved at some point :)
--
Calvin Walton <[email protected]>
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