[syslinux] [PATCH] Fix booting off a btrfs subvolume

[Alexander E. Patrakov]

2012/6/5 H. Peter Anvin <hpa at zytor.com>:
> On 06/04/2012 11:10 AM, Alexander E. Patrakov wrote:
>> The attached patch fixes booting off a btrfs subvolume for me.
>>
>> I have only tested the situation when the boot subvolume is made the
>> default subvolume with "btrfs subvolume set-default boot ."
>>
>> Since I am going to remove all traces of btrfs from my computer for
>> reasons unrelated to syslinux, I will not be able to answer any
>> requests for testing modified versions of this patch if they are sent
>> later than tomorrow.
>>
>
> Thank you!  Just one quick question: how was your subvolume mounted?
> Explicitly via mount -o, automatically, or was it the root?

The "boot" subvolume was created (as a non-root subvolume), made the
default subvolume and mounted at /boot via fstab. My root filesystem
is not on the (otherwise empty) btrfs root subvolume. In other words:

root subvolume (subvolid=5) = empty
ID 256 top level 5 path ext2_saved = will revert to this
ID 257 top level 5 path home = mounted at /home via fstab with option
subvol=home
ID 258 top level 5 path gentoo = root filesystem, mounted with
dracut's option rootflags=subvol=gentoo
ID 259 top level 5 path boot = default subvolume, and mounted at /boot
via fstab with no special options

and there are other, non-btrfs partitions.

-- 
Alexander E. Patrakov