Add an errortag mount option that enables an errortag with the default injection frequency. This allows injecting errors into the mount process instead of just on live file systems, and thus test mount error handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Signed-off-by: Carlos Maiolino <cem@kernel.org>