Re: [PATCH] Improve ext2 driver to allow embedding of the boot loader code.

[Andrey Borzenkov]

On Tue, Jan 21, 2014 at 12:32 PM, Vladimir 'φ-coder/phcoder'
Serbinenko <address@hidden> wrote:
> On 21.01.2014 09:28, Andrey Borzenkov wrote:
>> On Tue, Jan 21, 2014 at 12:14 PM, Vladimir 'φ-coder/phcoder'
>> Serbinenko <address@hidden> wrote:
>>> On 10.01.2014 08:49, Dr. Tilmann Bubeck wrote:
>>>>
>>>> The blocklist is fixed and stable and will never change.
>>> What guarantees that it won't change on grub-setup invocation? I'm under
>>> impression that it will change on every grub-setup invocation as file
>>> gets recreated.
>>>
>>
>> If I read code correctly, it checks current size and if new core.img
>> fits, space is reused. So we could effectively make it preallocate
>> reasonable size (or even unreasonable - I guess 10MB will be enough
>> for foreseeable future) the very first time it is done.
>>
> It still doesn't solve the problem that during operations file becomes a
> normal file and OS is allowed to rearrange the blocks as it sees fit.

Would this be acceptable - use external utility to allocate
EXT2_BOOT_LOADER_INO space of sufficient size once (outside of grub at
all) and allow embedding into extX if this space exists? Do not mess
with with it in grub-setup itself?

We could then speak with ext2 folks to add option to mke2fs/une2fs in
the long run it it does not exist yet.