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From: C Anthony Risinger <>
Subject: default subvolume abilities/restrictions
Date: Wed, 19 May 2010 01:50:27 -0500	[thread overview]
Message-ID: <> (raw)


i'm working on an initrd hook
[] to support
non-volatile system rollbacks (promoting a temporary rollback snapshot
to the new active/default).  when the system is installed to the
default/"." subvolume (as many users probably initially do), it is
more difficult/messier to manage system state; there are empty folders
in each "child" snapshot where a subvolume used to exist (this seems
like BUG to me, dir should not exist?) in the default subvolume. these
grow/vary with time.  to work around this and for cleaner
implementation, i'll intend to permanently boot a named subvolume
[__active] (though its contents may be swapped out).  ultimately, i
have to tell the user to manually remove the old junk (/usr, /etc,
/var, etc...) from the default subvolume (since its really in the
/__active subvolume)

moving along to a question... can the default subvolume be

what would have been useful, would be the ability to generate an
empty, parent subvolume to _contain_ the current one, and rename it to
__active.  btrfs gives rise to a "subroot" structure; the structure
beneath the root.

is something like this possible or can be added?

an alternative idea i had was "promoting" a subvolume to be the new
root, and anything "above" the new root is lost/forgotten.  then i
could create the subroot structure in a subvol, snapshot the default
subvol to where i want it, and promote the subvol to be the new root.
like a permanent pivot_root/chroot.

great stuff,

C Anthony

             reply	other threads:[~2010-05-19  6:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-19  6:50 C Anthony Risinger [this message]
2010-05-19 14:20 ` default subvolume abilities/restrictions Chris Ball
2010-05-19 14:55   ` C Anthony Risinger
2010-05-19 11:56 R: " kreijack
2010-05-19 14:01 ` C Anthony Risinger
2010-05-19 17:58   ` Goffredo Baroncelli
2010-06-12  5:24   ` C Anthony Risinger
2010-06-12 23:06     ` C Anthony Risinger
2010-06-13  0:22       ` David Brown
2010-06-13  1:06         ` C Anthony Risinger
2010-06-13 17:47           ` C Anthony Risinger
2010-06-18 21:01             ` C Anthony Risinger
2010-06-29 13:20               ` Hubert Kario
2010-06-29 15:23                 ` Goffredo Baroncelli

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