loop += Nicholas, who has been working on btrfs integration. Cheers, -- Cyril Brulebois (k...@debian.org) <https://debamax.com/> D-I release manager -- Release team member -- Freelance Consultant
Osamu Aoki <os...@debian.org> (2021-02-20): > Hi, > > Knowing bulleseye 11 release is near and this issue may stay, people > may need to work around this issue of btrfs subvolume as root > partition. Here is my WORKAROUND suggestion. > > (Please note that my patch proposal in my original bug report is not- > yet tested well.) > > The current Debian Grub2 code at /etc/grub.d/30_os-prober requires to > access some root partion contents from the btrfs ID 5 (FS_TREE) to > function well. (subvol=/) > > If you want to use timeshift (Ubuntu origin?) or snapper (Suse origin > ?), they seem to use non-ID-5 subvol for the system install, i.e., > root-FS. People use these tools on Debian too. > > https://qa.debian.org/popcon-graph.php?packages=timeshift+snapper+snapper-gui+btrbk+btrfsmaintenance+duperemove&show_installed=on&want_legend=on&want_ticks=on&from_date=&to_date=&hlght_date=&date_fmt=%25Y-%25m&beenhere=1 > > > === WORKAROUND === > > Let's suppose your another linux installation on another formatted in > btrfs at partion "/dev/nvme1n1p1" has its root-FS content in > "subvol=@", please perform followings: > > ----- > $ sudo mount -t btrfs -o subvol=/,defaults /dev/nvme1n1p1 /mnt > $ cd /mnt > $ sudo ln -sf @/boot boot > $ sudo ln -sf @/etc etc > $ sudo ln -sf @/usr usr > $ sudo ln -sf @/lib lib > $ sudo ln -sf @/initrd.img initrd.img > $ sudo ln -sf @/vmlinuz vmlinuz > $ sudo ln -sf @/initrd.img.old initrd.img.old > $ sudo ln -sf @/vmlinuz.old vmlinuz.old > $ sudo btrfs subvol set-default /mnt/@ > $ cd / > $ sudo umount /mnt > ----- > > This assumes you do not have conflicting contents in subvol=/. > > If you happen to use other subvol for the root-FS content, replace its > subvol name in place of "@". > > > === Additional Tips === > > You can convert a system from EXT2/3/4 to btrfs as follows by booting > system from another system on the multiboot set-up. > > File system conversion is trivial as described in > https://btrfs.wiki.kernel.org/index.php/Conversion_from_Ext3 > > ----- > $ sudo fsck.ext3 -f /dev/xxx > $ sudo btrfs-convert /dev/xxx > $ sudo mount -t btrfs /dev/xxx /mnt > ----- > > You need to make some adjustment to cope with new filesystem ant its > new blkid by adjustng at least /etc/fstab and /boot/grub/grub.cfg . > > Please note UUID of partition changes after btrfs-convert. > Please check > > ----- > --- fstab.orig 2021-02-19 14:49:32.768895933 +0900 > +++ fstab 2021-02-19 14:49:19.860921576 +0900 > @@ -6,6 +6,6 @@ > # > # <file system> <mount point> <type> <options> <dump> <pass> > # / was on /dev/nvme1n1p1 during installation > -UUID=491a357c-822f-4f38-b56e-b998baea81a5 / ext4 > errors=remount-ro 0 1 > +UUID=9be0d928-5892-4cdd-a647-1e8cce937b2e / btrfs defaults > 0 1 > # /boot/efi was on /dev/nvme0n1p1 during installation > ----- > > > Also, you need to update many relevant parts of grub.cfg, too. Roughly > as ... > ----- > --- grub.cfg-orig 2021-02-17 09:32:35.855910912 +0900 > +++ grub.cfg 2021-02-19 14:26:12.728005239 +0900 > ... > -insmod ext2 > +insmod btrfs > ... > - search --no-floppy --fs-uuid --set=root 491a357c-822f-4f38-b56e- > b998baea81a5 > + search --no-floppy --fs-uuid --set=root 9be0d928-5892-4cdd-a647- > 1e8cce937b2e > ... > - linux /boot/vmlinuz-5.10.0-3-amd64 root=UUID=491a357c-822f- > 4f38-b56e-b998baea81a5 ro quiet > + linux /boot/vmlinuz-5.10.0-3-amd64 root=UUID=9be0d928-5892- > 4cdd-a647-1e8cce937b2e ro quiet > ... > ----- > > The UUID change to the "linux ..." line is important since it will > affect how this alternative partion update is grub configuration. > > If you wish to move all this nely migrated system to a subvolume, just > snapshot it to "@" or anything you like using "btrfs subvolume snapshot > /mnt /@" command. > > Of course, if your new system is at subvol=@, you need to adjust > /etc/fstab as; > > ----- > --- fstab.orig 2021-02-19 14:49:32.768895933 +0900 > +++ fstab 2021-02-19 14:49:19.860921576 +0900 > @@ -6,6 +6,6 @@ > # > # <file system> <mount point> <type> <options> <dump> <pass> > # / was on /dev/nvme1n1p1 during installation > -UUID=491a357c-822f-4f38-b56e-b998baea81a5 / ext4 > errors=remount-ro 0 1 > +UUID=9be0d928-5892-4cdd-a647-1e8cce937b2e / btrfs > subvol=@,defaults 0 1 > # /boot/efi was on /dev/nvme0n1p1 during installation > ----- > > And then move on to use WORKAROUND as described in the above. > > On Fri, 2021-02-19 at 14:12 +0000, Debian Bug Tracking System wrote: > > ... > > You can follow progress on this Bug here: 983107: > > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=983107.
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