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

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

On Fri, 16 Jan 2009 20:16:55 +0900, "Csaba Kos" wrote:
> On Fri, Jan 16, 2009 at 8:07 PM, Ryusuke Konishi wrote:
> > On Fri, 16 Jan 2009 19:22:46 +0900, "Csaba Kos" wrote:
> >> Hi!
> >>
> >> Sorry to chime in uncalled, but I noticed that you are trying to mount
> >> "/dev/sdb".
> >> I have to admit that it has been a while since I last mounted a
> >> pendrive from the
> >> command line, so I might be wrong, but usually one mounts partitions
> >> on the device,
> >>  like "/dev/sdb1", and not the device itself.
> >
> > No, no. That's OK.
> > NILFS does not overwrite the partition table block, so is available
> > for the device itself.
> > Of course, it's unless there's a bug for this usage ;)
> Ah, sorry, I didn't know about that and thank you for the heads up. So
> sdb and sdb1 is basically equivalent for nilfs?

No. If you did mkfs for sdb, the mount device must be sdb (not sdb1),
and the opposite is true.  So they differ.

> Is this a nilfs-specific feature?

I believe most filesystems can do this.
One of the merits to use device itself is that it can align the
disk area without inserting offset sectors.

Since performance of flash devices is often sensitive to alignment of
sectors, this style is occasionally used.

Cheers,
Ryusuke

> Regards,
> 
> Csaba
> 
> >
> > Ryusuke
> >
> >> Regards,
> >>
> >> Csaba Kos
> >>
> >> On Fri, Jan 16, 2009 at 6:38 PM, Milos Jana <milosdsax-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> >> > user@laptop:~/prog/sources/nilfs-utils-2.0.6$ sudo fsck0.nilfs2 /dev/sdb
> >> > [sudo] password for user:
> >> > Super-block:
> >> >   revision = 2.0, checksum = OK
> >> >   blocksize = 4096
> >> >   write time = 2008-12-28 09:48:42
> >> >   indicated partial segment: blocknr = 4263936
> >> >   segnum = 2082, seq = 11746, cno=6661
> >> >
> >> > empty or bad segment: segnum = 2082, blocknr = 4263936
> >> > The latest segment is lost. Trying rollback recovery..
> >> > .
> >> > Searching the latest checkpoint.
> >> > Selected segment: blocknr = 4261888
> >> >   segnum = 2081, seq = 11745, cno=6660
> >> >   creation time = 2008-12-28 09:48:34
> >> > Do you wish to overwrite super block (y/N)? Y
> >> > Recovery will complete on mount.
> >> > user@laptop:~/prog/sources/nilfs-utils-2.0.6$ sudo mount /media/pendrive/
> >> > mount.nilfs2: Error while mounting /dev/sdb on /media/pendrive: Invalid
> >> > argument
> >> >
> >> > dmesg returns the same errors:
> >> > [ 553.003240] NILFS warning: Segment magic number invalid
> >> > [ 553.003248] NILFS: error searching super root.
> >> >
> >> > On Fri, Jan 16, 2009 at 8:55 AM, Ryusuke Konishi <ryusuke-sG5X7nlA6pw@public.gmane.org> wrote:
> >> >>
> >> >> On Thu, 15 Jan 2009 19:10:19 +0100, "Milos Jana" wrote:
> >> >> > Nilfs-utils compiled properly with patch after following instructions
> >> >> > from
> >> >> > your previous post. Here is what came out:
> >> >> >
> >> >> > user@laptop:~$ sudo fsck0.nilfs2 /dev/sdb
> >> >> > Super-block:
> >> >> >   revision = 2.0, checksum = OK
> >> >> >   blocksize = 4096
> >> >> >   write time = 2008-12-28 09:48:42
> >> >> >   indicated partial segment: blocknr = 4263936
> >> >> >   segnum = 2082, seq = 11746, cno=6661
> >> >> >
> >> >> > Clean FS.
> >> >> >
> >> >> > user@laptop:~$ sudo mount /media/pendrive/
> >> >> > mount.nilfs2: Error while mounting /dev/sdb on /media/pendrive: Invalid
> >> >> > argument
> >> >>
> >> >> Hmm, that's weird.
> >> >>
> >> >> The partition was cleanly unmounted, but the final segment seems not
> >> >> to be written to the disk.
> >> >>
> >> >> Maybe, we need 'force' option to treat such situation.
> >> >>
> >> >> In the meatime, could you try the following (additional) patch?
> >> >>
> >> >> Regards,
> >> >> Ryusuke
> >> >> --
> >> >>
> >> >> diff --git a/sbin/mkfs/fsck0.nilfs2.c b/sbin/mkfs/fsck0.nilfs2.c
> >> >> index d3d335f..0d51e54 100644
> >> >> --- a/sbin/mkfs/fsck0.nilfs2.c
> >> >> +++ b/sbin/mkfs/fsck0.nilfs2.c
> >> >> @@ -905,10 +905,12 @@ static void nilfs_fsck(const char *device)
> >> >>        print_pseg_message(&pseg_ref, "    indicated partial segment");
> >> >>        fputc('\n', stderr);
> >> >>
> >> >> +#if 0
> >> >>        if (le16_to_cpu(sb.s_state) & NILFS_VALID_FS) {
> >> >>                fprintf(stderr, "Clean FS.\n");
> >> >>                goto out_clean;
> >> >>        }
> >> >> +#endif
> >> >>
> >> >>        if (nilfs_do_recovery(devfd, &pseg_ref) == 0)
> >> >>                goto out;
> >> >
> >> >
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> >> >
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