On 2021/9/1 下午9:48, Matthias Brugger wrote:
On 01/09/2021 13:36, Tom Rini wrote:
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.korni...@gmail.com>
Reviewed-by: Qu Wenruo <w...@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!
It's a bugfix, as loading files from BTRFS, at least in openSUSE does not work
without it.
Just to be extra accurate, the original code always accesses subvol 5 as
the entrance point, thus for openSUSE or any other distros setting other
default subvolume, this will cause behavior difference between kernel
and u-boot, thus unable to find the correct /boot path.
This problem is cause by my rework using btrfs-progs code. All my fault.
Btrfs-progs never needs to bother the default subvolume, as it has no
way to "mount" the fs nor explore the directories/files structure.
Thus it's a regression, and I'm not sure if we should use Fixes: tag.
Just in case, the fixes tag is:
Fixes: f06bfcf54d0e ("fs: btrfs: Crossport open_ctree_fs_info() from
btrfs-progs")
Thank all guys involved in this case.
Qu
Thanks for the quick answer!
Matthias
