Validate the symlink xattr is stored on first data
object of the symlink along with backtrace if
'mds_symlink_recovery' option is enabled and
vice-versa.
Also add 'string_wrapper' class to decode bufferlist
to string. This helps 'ceph-dencoder' tool to decode
the symlink target stored, which is used in tests to
validate.
Signed-off-by: Kotresh HR <khiremat@redhat.com>
Fixes: https://tracker.ceph.com/issues/46166