On Wed, Sep 01, 2021 at 01:28:30PM +0200, Matthias Brugger wrote:
Hi Tom,
On 02/08/2021 01:06, Qu Wenruo wrote:
On 2021/8/2 上午4:52, Matwey V. Kornilov wrote:
BTRFS volume consists of a number of subvolumes which can be mounted separately from each other. The top-level subvolume always exists even if no subvolumes were created manually. A subvolume can be denoted as the default subvolume i.e. the subvolume which is mounted by default.
The default "default subvolume" is the top-level one, but this is far from the common practices used in the wild. For instance, openSUSE provides an OS snapshot/rollback feature based on BTRFS. To achieve this, the actual OS root filesystem is located into a separate subvolume which is "default" but not "top-level". That means that the /boot/dtb/ directory is also located inside this default subvolume instead of top-level one.
However, the existing btrfs u-boot driver always uses the top-level subvolume as the filesystem root. This behaviour 1) is inconsistent with
mount /dev/sda1 /target
command, which mount the default subvolume 2) leads to the issues when /boot/dtb cannot be found properly (see the reference).
I also noticed the problem in the past, but forgot to fix it....
This patch uses the default subvolume as the filesystem root to overcome mentioned issues.
Reference: https://bugzilla.suse.com/show_bug.cgi?id=1185656 Signed-off-by: Matwey V. Kornilov matwey.kornilov@gmail.com
Reviewed-by: Qu Wenruo wqu@suse.com
I can see that this patch is marked in your patchwork queue as "Need Review / ACK". Qu is one of our core btrfs developer who reviewed the patch. Apart from that we have it running on openSUSE on top of v2021.07 for some time without any issues.
Ah, yup. Qu is one of the people I do look for to have reviewed a btrfs patch before I apply it (and I throw things under Need Review / ACK as a note-to-self to make sure a patch does have one, when I can expect one, before applying, FWIW).
Would it be possible to merge this for v2021.10 or do you see any blocker here?
I think I had mentally filed it was feature not bugfix and was going to hold off, but since you're asking, yes, I can grab it for this release. Thanks!