copyin: fix error handling

Save errno (in retval) before doing anything else, because the
"anything else" (usually com_err()) can call library functions, which
will reset errno.

Fix the error messages to use the message catalog, and don't _ever_
print an error without providing context.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
3 files changed