Comment 12 for bug 293465

On Tue, Dec 23, 2008 at 5:17 AM, Theodore Ts'o <email address hidden> wrote:
> "mke2fs -S" is __very__ dangerous unless you give it exactly the same
> arguments that was used to make the filesystem in the first place (which
> probably in this case was something like "mke2fs -t ext4 /dev/sda1", so
> you have to use "mke2fs -t ext4 -S /dev/sda1" if you want to have any
> hope of mke2fs -S _not_ trashing your filesystem.
>
> In this case it wouldn't have helped you much, given that e2fsck was
> able to use the fallback superblocks just fine. The failure was due to
> a bug in e2fsck -- specifically, an unhandled case where an interior
> node has a corrupted extent header. The cases where this will even
> show up is quite rare; I have one inode out of the 760,486 inodes in use
> that would even potentially be vulnerable to this failure (where the
> extent tree depth is >=2). In any case, I'll get this fixed in the
> next version of e2fsck's maintenance release.
>
> --
> make ext4 as the primary filesystem for GNU/Linux
> https://bugs.launchpad.net/bugs/293465
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>

I did mkfs.ext4 -S