Re: rollback of a snapshot is just read-only

[Juergen Sauer <juergen.sauer@automatix.de>]

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Am 24.04.2015 um 16:08 schrieb Lentes, Bernd:
> Hi,
> 
> it should be just a small problem, but it is one. How can I rollback t
o a snapshot of my root filesystem ?
> Googeling, I found a lot of solutions, each different.
> I finally choosed this one: https://btrfs.wiki.kernel.org/index.php/Us
eCases#I_want_to_be_able_to_do_rollbacks_with_Btrfs
> 
> I made the snapshot, changed some configuration, and afterwards I'd li
ke to rollback to the snapshot:
> 
> - btrfs subvolume snapshot -r  /  /.snapshots/vor_nvidia
> 
> - change some configuration
> 
> - btrfs subvolume set-default 625 (id of the snapshot)
> 
> - reboot
...

It seems, that you has set the RO "readonly" flag on the subvolume.
The btrfs tool may se/unset the flag like

# mount /dev/sdXY /mnt -o subvol=/
# btrfs su list .
ID 258 gen 13711 top level 5 path backup
[ ... ]
# btrfs prop list backup
ro                  Set/get read-only flag of subvolume.
compression         Set/get compression for a file or directory

root@pc6:/mnt# btrfs prop get backup
ro=true
root@pc6:/mnt# btrfs prop set backup ro false
root@pc6:/mnt# btrfs prop get backup
ro=false

This worked on:
root@pc6:/mnt# uname -a ; btrfs --version
Linux pc6 3.19.3-3-ARCH #1 SMP PREEMPT Wed Apr 8 14:10:00 CEST 2015
x86_64 GNU/Linux
btrfs-progs v3.19

mit freundlichen Grüßen
Jürgen Sauer
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