stuck with ufs CHECK-HASH errors

[Kirk McKusick]

> Date: Mon, 3 Dec 2018 23:08:50 -0800 (PST)
> From: Don Lewis <truckman at FreeBSD.org>
> Subject: Re: stuck with ufs CHECK-HASH errors
> To: Kirk McKusick <mckusick at mckusick.com>
> cc: freebsd-fs at FreeBSD.org
> 
> On  3 Dec, Kirk McKusick wrote:
> > I am working on a fix. Hopefully have it in no more than a day.
> 
> I figured out that ufs_disk_fillout() and therefore sbread() in libufs
> is never getting called.  Therefore the superblock used by cgput() is
> all zeros.  If I change the call to ufs_disk_fillout_blank() in setup()
> to ufs_disk_fillout() then things appear to work much better.

Yeah, that was my first attempt at a fix, but if the superblock has
a check-hash error, then fsck_ffs bails out at the ufs_disk_fillout()
call without getting down to the code that looks for alternate superblocks.
So, cannot use your fix long-term.

	Kirk McKusick