Re: [PATCH v4 1/3] fs: hoist EFSCORRUPTED definition into uapi header

[Theodore Y. Ts'o]

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@xxxxxxxxxxxxxxx
> Suggested-by: Dave Chinner <david@xxxxxxxxxxxxx>
> Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>

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