Re: [Bug 485507] RFE: add ext4 to "stat -f" output

[Bauke Jan Douma]

Eric Sandeen wrote on 02/16/2009 06:53 PM:
> Jim Meyering wrote:
> > > > How much code (and how ugly) would be required to distinguish ext4
> > > > from ext[23]?
> > > it'd need to be able to do some parsing of the ext2/3/4 feature flags,
> > > so it'd need to know some ext2/3/4 details.
> > >
> > > lib/blkid/probe.c in e2fsprogs is an example, see probe_ext2,
> > > probe_ext3, etc.  It reads in the superblock and then checks some of the
> > > feature fields, for example:
> > >
> > >         /* Ext4 has at least one feature which ext3 doesn't understand */
> > >         if (!(blkid_le32(es->s_feature_ro_compat) &
> > >               EXT3_FEATURE_RO_COMPAT_UNSUPPORTED) &&
> > >             !(blkid_le32(es->s_feature_incompat) &
> > >               EXT3_FEATURE_INCOMPAT_UNSUPPORTED))
> > >                 return -BLKID_ERR_PARAM;
> > >
> > > so it'd not be rocket science but it might be a lot more fs details than
> > > you'd really want in coreutils, I'm not sure...
> > Would you mind writing some proof-of-concept code for that?
> > If it's not too big or ugly, I'd like to teach stat -f
> > to distinguish ext4 from ext2/3.
>
> Ok, I'll put it on the TODO list.  :)
>
> Thanks,
> -Eric

Might the linux klibc code for fstype be a source for this?
I'm not sure myself, I just looked in those for klibc-1.5.tar.gz,
(dated 2007, the latest?) and there doesn't to be code for ext4...

bjd