this gets rid of the

#ifdef XFS_BMAP_TRACE
        static char             fname[] = "xfs_iextents_copy";
#endif

ugliness littered in the bmap code for tracing, and instead just uses 
gcc's __FUNCTION__, which never gets out of sync with the actual 
function name....

It also makes some of this tracing more consistently use the

#define        XFS_BMBT_TRACE_ARGBI(c,b,i)     \
        xfs_bmbt_trace_argbi(__FUNCTION__, c, b, i, __LINE__)

type constructs, to automatically pick up the gcc extensions.

the vn tracing could probably get a similar treatment, so that every 
call to vn_trace_foo wouldn't have to include a function name and a 
__builtin_return_address, but could be done via macros... it's currently 
a mishmash of __FUNCTION__ and "function" *shrug* what do you think?

-Eric