[v2] xfstests: add support for ext4dev FSTYP

On Fri, Jun 3, 2011 at 8:06 AM, Eric Sandeen <sandeen@redhat.com> wrote:
> On 6/2/11 11:59 PM, Amir G. wrote:
>> On Fri, Jun 3, 2011 at 3:36 AM, Ted Ts'o <tytso@mit.edu> wrote:
>>> On Thu, Jun 02, 2011 at 11:22:53AM -0600, Andreas Dilger wrote:
>>>> On 2011-06-02, at 8:59 AM, Eric Sandeen wrote:
>>>>> I don't really mind adding ext4dev to FSTYP case statements, it
>>>>> -is- something which blkid could, in theory, still return, and
>>>>> making xfstests cope with that and try to invoke fsck -t ext4dev
>>>>> doesn't bother me too much.  It is sadly an fs type embedded into
>>>>> a few tools.
>>>>
>>>> I'm perfectly OK with using ext4dev as a filesystem type that allows testing
>>>> changes to ext4 on a system that is already running ext4 as the root fs.
>>>
>>> My take on this is that way too much time has been spent this subject.
>>
>> No doubt.
>>
>>> Being able to use ext4dev is useful, and given that we have all of
>>> this support in our existing system tools, why not use it to make ext4
>>> development more efficient/easy?  As a bonus you can build the ext4dev
>>> as a module, and that means you the compile/edit/debug cycle can be
>>> much faster since you can avoid doing a reboot, for those
>>> circumstances where using KVM is not possible/convenient.  Personally,
>>> I normally use KVM these days, but I can imagine situations where
>>> using ext4dev would be a better way to go.  For example, I'd probably
>>> use KVM on my laptop, but for testing on production servers in a data
>>> center, I'd probably use ext4dev, for a variety of local deployment
>>> considerations that's not worth going into here.
>>>
>>> That being said, whether or not we modify xfstests seems to be a moot
>>> point.  In order for me to do my bigalloc development, I've been
>>> patching common.rc so that "/sbin/mkfs.$FSTYP" --> "mkfs.$FSTYP" and
>>> "/sbin/fsck -t $FSTYP" --> "fsck.$FSTYP".  It's a 3 line change.  Not
>>> a big deal.  I've been making this change using /bin/ed after
>>> installing xfstests.  So if the XFS folks want to veto this change ---
>>> who cares?  It's not hard to make the change locally in order to make
>>> xfstests.
>>>
>>> On the other hand, given that xfstests is using "mkfs.$FSTYP", I don't
>>> see why it's so important that it clings to "fsck -t $FSTYP" instead
>>> of using "fsck.$FSTYP".  There's no real benefit to calling the fsck
>>> driver; it's just an extra fork and exec, and xfstests is being
>>> inconsistent by insisting on the use of the fsck driver, but not using
>>> the mkfs driver.
>>>
>>> But that being said, hacking xfstests is not hard, and if Dave and/or
>>> Eric feels strongly about resisting this change, it's not worth a lot
>>> of time, one way or another....
>>>
>>>                                                - Ted
>>>
>>
>> I blame only myself for not presenting the case correctly.
>> I made it sound like I am trying to push my own private hack upstream.
>> Actually, all 10 people involved in snapshot development clone my xfstests
>> tree from github, so we have no real need for the upstream change.
>> The reason I was pushing upstream is because I found this feature
>> so useful, I thought other developers may enjoy it as well.
>>
>> Anyone on on this thread not having used ext4dev by next LSF
>> can come to me to claim his beer ;-)
>
> mmm I like beer, I'll see you then!  ;)
>
> -Eric (tucking this email away for future reference... ;)
>

Well, if anyone doesn't like beer, here are my low-tech ext4dev clone
scripts ;-)

ext4: scripts to clone and build ext4dev fs with default config options

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