Heads up on ext4 changes

[Eric Sandeen]

Tom London wrote:
> On Sat, Oct 11, 2008 at 2:45 PM, Eric Sandeen <sandeen at redhat.com> wrote:
>> Tom London wrote:
>>> On Fri, Oct 10, 2008 at 12:10 PM, Eric Sandeen <sandeen at redhat.com> wrote:
>>>> Eric Sandeen wrote:
>>>>
>>>>> Changing /etc/fstab to list "ext4" for the root fs may be enough, do it
>>>>> before you install the new kernel.
>>>> On further reflection, you will probably just have to do this.
>>>>
>>>> -Eric
>>>>
>>>>> notting suggested a module alias to ext4dev in the ext4.ko module
>>>>> itself, that sounds like a good plan and as long as it gets upstream
>>>>> I'll commit it to Fedora shortly, and I think that should make it all
>>>>> seamless.
>>> I have an 'ext4' FS on a USB hard drive.  When I plug this in, I get a
>>> "Cannot mount volume" popup:
>>>
>>> The volume 'Backup1' uses the ext4dev file system which is not
>>> supported by your system, followed by a dbus-type failure error
>>> message about a minute later.
>>>
>>> This just me, or what additional changes are needed?
>> Do you have the most recent e2fsprogs?  And/or what does blkid
>> /dev/whatever say... if it says ext4dev, try newer e2fsprogs - blkid had
>> a bug that caused it to say "ext4dev" when "ext4" is what we wanted.
>>
>> Going forward I think we'll register both ext4 & ext4dev from the ext4
>> kernel module, at least for a while, so that "mount -t ext4dev" will
>> work still work in the transition period.
>>
>> Sorry for all the hassle :)
>>
>> -Eric
>>
> No hassle, this is fun! ;)
> 
> Anyway:
> 
> [root at tlondon ~]# rpm -q e2fsprogs
> e2fsprogs-1.41.2-2.fc10.i386
> [root at tlondon ~]# blkid /dev/sdb1
> /dev/sdb1: LABEL="Backup1" UUID="7066e635-fe1f-4cf8-94a6-1a3e9229a44c"
> TYPE="ext4"
> [root at tlondon ~]#
> 
> Guessing that something is compiled with 'ext4dev' (not 'ext4'), I did
> 'strings | grep ext4' in the usual places (/bin, /sbin, /usr/bin,
> /usr/sbin/, /usr/libexec, /usr/lib).  Here is what I got (omitting
> those that appeared to have both 'ext4' and ext4dev'):
> 
> /sbin/quotacheck
> ext4dev

crud, you're right:

#define MNTTYPE_EXT4            "ext4dev"       /* ext4 filesystem */

we'll need to update that.

Thanks,
-Eric