Re: Can't mount nilfs - error searching super root.

[Ryusuke Konishi <ryusuke-sG5X7nlA6pw@public.gmane.org>]

Hi,
On Wed, 11 Feb 2009 16:09:32 +0100, Milos Jana wrote:
> Uhm... does it mean that data from my pendrive in unrecoverable? Is there
> any chance that future release on fsck0.nilfs will be able to recover it?
> On Fri, Jan 30, 2009 at 1:03 PM, Ryusuke Konishi <ryusuke-sG5X7nlA6pw@public.gmane.org> wrote:

Oh, sorry. I once looked into the fsck0, but it was paused because I
had to do so many things.  I'll increase priority for this if you
really need it.  Meanwhile I'm worrying that the same trouble occurs
again and again even if fsck0 will be improved.

I feel we think removing the cause of the problem because
making better fsck will take some time.
And I wonder why the pendrive does not write all data for cleanly
unmounted partition so often.  It may need bugfix for the device driver,
for example it may have a silent error problem (i.e. it may complete
I/O operations even if it couldn't handle them properly).

Anyway, I will be able to back to fsck0 after a while.

Regards,
Ryusuke

> > Hi,
> > On Sat, 24 Jan 2009 01:13:41 +0100, Milos Jana wrote:
> > > Hi again,
> > >
> > > Looks like I'm unable to mount this drive again. It mounted successfully
> > > several times after following your previous posts, but yesterday the
> > problem
> > > came back. I'm sure that I have been mounting/unmounting my pendrive
> > > properly.
> >
> > Hmm, it's abnormal that this occurs so often.
> > The partition was cleanly unmounted, but the latest segment was not
> > written.
> > The usb device seems to lack proper support of cache flushing if it
> > occurs just before power-off.
> >
> > The usb stack of Linux is often problematic, but this looks terrific.
> >
> > > This time fsck0.nilfs2 doesn't help - it hangs with "Searching the
> > > latest checkpoint." message (see below).
> >
> > All right, I'll look into the hang problem.
> >
> > Please note that the fsck0 is not a complete solution.
> > To make it better, we need a few changes on the disk format.
> >
> > Regards,
> > Ryusuke
> >
> > > user@laptop:~$ sudo mount /media/pendrive/
> > > mount.nilfs2: Error while mounting /dev/sdb on /media/pendrive: Invalid
> > > argument
> > >
> > > user@laptop:~$ dmesg
> > > ...
> > > [22429.446924] NILFS warning: Segment magic number invalid
> > > [22429.446932] NILFS: error searching super root.
> > >
> > > user@laptop:~/prog/sources/nilfs-utils-2.0.6$ sudo fsck0.nilfs2 /dev/sdb
> > #
> > > Nilfs-tools with first patch applied
> > > Super-block:
> > >   revision = 2.0, checksum = OK
> > >   blocksize = 4096
> > >   write time = 2009-01-22 23:40:19
> > >   indicated partial segment: blocknr = 1966080
> > >   segnum = 960, seq = 18266, cno=10169
> > >
> > > Clean FS.
> > >
> > > user@laptop:~/prog/sources/nilfs-utils-2.0.6$ sudo fsck0.nilfs2 /dev/sdb
> > #
> > > Nilfs-tools with additional patch applied
> > > Super-block:
> > >   revision = 2.0, checksum = OK
> > >   blocksize = 4096
> > >   write time = 2009-01-22 23:40:19
> > >   indicated partial segment: blocknr = 1966080
> > >   segnum = 960, seq = 18266, cno=10169
> > >
> > > empty or bad segment: segnum = 960, blocknr = 1966080
> > > The latest segment is lost. Trying rollback recovery..
> > > .
> > > Searching the latest checkpoint.    # here it hanged for like 10 minutes
> > > until I killed it
> >