[PATCH] xfstests: add support for ext4dev FSTYP

[sergey ivanov]

On Wed, Jun 1, 2011 at 2:37 AM, Amir Goldstein <amir73il at gmail.com> wrote:

> On Wed, Jun 1, 2011 at 8:34 AM, Eric Sandeen <sandeen at redhat.com> wrote:
> > On 6/1/11 12:22 AM, Eric Sandeen wrote:
> >> On 5/31/11 11:56 PM, Amir Goldstein wrote:
> >>> On Wed, Jun 1, 2011 at 7:37 AM, Eric Sandeen <sandeen at redhat.com>
> wrote:
> >>>> On 5/31/11 10:13 PM, Amir Goldstein wrote:
> >>>>> From: Amir Goldstein <amir73il at users.sf.net>
> >>>>>
> >>>>> blkid knows to identify the ext4dev FSTYP of a partition that was
> >>>>> formatted with mkfs.ext4dev.
> >>>>> quota tools and various util-linux utils are also aware of ext4dev,
> >>>>> so ext4dev shares the same capabilities as ext4.
> >>>>>
> >>>>> While testing on Fedora 15, we encoutered a buggy fsck utility, which
> >>>>> invokes fsck.ext4, even though it was called with -t ext4dev
> argument.
> >>>>> In our setup fsck.ext4dev knows about new fs features that fsck.ext4
> >>>>> doesn't know, so the generic_fs_check fails.
> >>>>> Since we have no real use of the extra capabilities provided by fsck
> util,
> >>>>> we decided to invoke fsck.$FSTYP directly to avoid this issue.
> >>>>
> >>>> Adding ext4dev to every case seems harmless enough.  TBH I thought I
> had
> >>>> it there already but I guess not.
> >>>>
> >>>> I'm less certain of the change from fsck -t $FSTYP to fsck.$FSTYP
> >>>>
> >>>> What issue are you avoiding?  wouldn't fsck -t ext4dev invoke
> fsck.ext4dev anyway?
> >>>>
> >>>> It seems like it should be harmless, but I don't understand how it
> helps you.
> >>>>
> >>>
> >>> As I wrote in the patch description, the fsck utility in Fedora 15
> invokes
> >>> fsck.ext4 for some reason when calling fsck -t ext4dev.
> >>
> >> Oh, right.
> >>
> >>> this fails because fsck.ext4 doesn't know the snapshot feature.
> >>> I didn't debug fsck utility for that. it seemed pointless.
> >>
> >> Did you file a bug with Fedora?  I'd rather fix the root cause than work
> around it...
> >> Feel free to cc: me on the bug.
>
> No, I didn't file a bug.
> In any case, it was Sergey, who tested and reported the problem on F15.
>
> Would you agree to fix the problem in xfstests now, so that F15 users can
> test ext4dev and fix the bug in fsck regardless?
>
> >
> > RHEL6 does the same; mkfs.ext4dev then fsck -t ext4dev invokes fsck.ext4;
> but this
> > is because blkid identifies it as ext4, not ext4dev, despite the test_fs
> flag being set.
> >
> > ISTR this is due to some tortured logic about when ext4dev isn't ext4dev,
> but
> > I don't remember the details... I don't know if this is the same
> situation
> > you're seeing; just to double check - does blkid correctly identify it as
> ext4dev
> > on F15?
>
>
> For me (on Ubuntu) blkid identifies ext4dev, but maybe the tortured logic
> finds unknown features a justification for declaring ext4dev?
> Segrey, can you answer the question for F15?
> Did you set FSTYP to ext4dev manually or did blkid identified it for you?
>

Amir, Fedora's fsck behaves differently on ext4dev and next4. When I made
next4 partition on Fedora-15 by
{{{
mkfs  -t next4 /dev/sdd9
}}}
it requires "export FSTYP=next4" to be defined and exported in local.conf.
It mounts partition with
{{{
mount -t next4 /dev/sdd9 /mnt/sdd9
}}}
But on attempt to fsck it calls wrong fsck, as you reported:
{{{
[seriv at pimbra xfstests]$ sudo fsck -t next4 /dev/sdd9
fsck from util-linux 2.19.1
e2fsck 1.41.14 (22-Dec-2010)
/dev/sdd9 has unsupported feature(s): FEATURE_C7 FEATURE_C8 FEATURE_R7
e2fsck: Get a newer version of e2fsck!
}}}

And the problem can be easily traced to this wrong call:
{{{
[seriv at pimbra xfstests]$ sudo strace -o /var/log/fsck.strace fsck -t next4
/dev/sdd9
fsck from util-linux 2.19.1
e2fsck 1.41.14 (22-Dec-2010)
/dev/sdd9 has unsupported feature(s): FEATURE_C7 FEATURE_C8 FEATURE_R7
e2fsck: Get a newer version of e2fsck!
[seriv at pimbra xfstests]$ grep sbin /var/log/fsck.strace
execve("/sbin/fsck", ["fsck", "-t", "next4", "/dev/sdd9"], [/* 17 vars */])
= 0
stat("/sbin/fsck.ext4", {st_mode=S_IFREG|0755, st_size=194280, ...}) = 0
}}}

But it's not the case for ext4dev, with it I even don't need "-t ext4dev",
it is recognized by blkid:
{{{
[seriv at pimbra xfstests]$ sudo mkfs -t ext4dev /dev/sdd9
mke2fs 1.41.14-next3-1.0.13-7 (24-May-2011)
[skip]
This filesystem will be automatically checked every 27 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.
[seriv at pimbra xfstests]$ sudo mount /dev/sdd9 /mnt/sdd9
[seriv at pimbra xfstests]$ mount | grep sdd9
/dev/sdd9 on /mnt/sdd9 type ext4dev (rw)
[seriv at pimbra xfstests]$ sudo umount /dev/sdd9
[seriv at pimbra xfstests]$ sudo fsck /dev/sdd9
fsck from util-linux 2.19.1
e2fsck 1.41.14-next3-1.0.13-7 (24-May-2011)
The test_fs flag is set (and ext4 is available).  Clear<y>?
}}}
and at this point in another session
{{{
[seriv at pimbra xfstests]$ pgrep -f -l fsck
4365 sudo fsck /dev/sdd9
4366 fsck /dev/sdd9
4367 fsck.ext4dev /dev/sdd9
}}}

So I'd like this patch to be applied to xfstests to be able to use it on the
different filesystems, - if not, then why have this FSTYP and not rely upon
blkid
-- 
  Regards,
   Sergey Ivanov.
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