On Fri, Jan 18, 2019 at 05:14:38PM +0100, Jann Horn wrote:

Multiple filesystems can already return EFSCORRUPTED errors to userspace;
however, so far, definitions of EFSCORRUPTED were in filesystem-private
headers.

I wanted to use EUCLEAN to indicate data corruption in the VFS layer;
Dave Chinner says that I should instead hoist the definitions of
EFSCORRUPTED into the UAPI header and then use EFSCORRUPTED.

This patch is marked for stable backport because it is a prerequisite for
the following patch.

Cc: stable@vger.kernel.org
Suggested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Jann Horn <jannh@google.com>

Before we enshrine the overloading of EUCLEAN and EFSCORRUPTED, I
wonder if we should at least consider the option of assigning a new
error code number for EFSCORRUPTED.  The downside of doing this is
that for a while, older versions glibc won't have strerror/perror
translation for the new error code.  On the other hand, I'm not sure
it will be that much more confusing to the average user than
"Structure needs cleaning".  :-)

The upside of assigning a new error code is that in a year or two,
we'll actually have an intelligible error message showing up in log
files and in user's terminals.

					- Ted