Re: [PATCH] Bug fix for ext2.c

[Bean]

On Sun, Mar 15, 2009 at 12:37 AM, Robert Millan <address@hidden> wrote:
> On Sun, Mar 15, 2009 at 12:16:23AM +0800, Bean wrote:
>> Hi,
>>
>> I've discovered a bug in ext2.c, inside grub_ext2_mount. The mount
>> function must return GRUB_ERR_BAD_FS if something goes wrong, because
>> grub_fs_probe would stop as soon as it sees a non-GRUB_ERR_BAD_FS
>> error, thus preventing other fs driver from detecting the correct fs
>> type. This patch fixes the problem.
>
> I think current behaviour is correct.  If a failure is triggered by
> grub_disk_read(), from grub_fs_probe perspective it means something is
> fucked up other than just "this is not the FS we're looking for", so it
> should be aware of the difference.
>
> Or is grub_ext2_read_inode() failure the one that's causing trouble for
> you?

Hi,

ext2 only reads the first two sectors in mount, which is normally ok ,
but there are exceptions. For example, cpio filesystem could be less
one sector. Also, hostfs always return error in its read function,
which would cause ext2 to fail. The effect can be seen in grub-fstest.
hostfs is the first fs driver to register, and the last to query. When
accessing the (host) device, ext2 cause it to fail before hostfs has a
chance to see it.

-- 
Bean