[PVFS2-developers] romio/pvfs2 auto-filesystem detection

[Pete Wyckoff]

The code in mpich2/src/mpi/romio/adio/common/ad_fstype.c
uses statfs() to determine the filesystem type in an
MPI_File_open() call when there is no "pvfs2:" or similar
prefix.  There's a section in there for many filesystems
to compare the f_type field returned from statfs(), each
of which is similar to:

    # ifdef PVFS2_SUPER_MAGIC
	if (fsbuf.f_type == PVFS2_SUPER_MAGIC) {
	    *fstype = ADIO_PVFS2;
	    return;
	}
    # endif

But nothing defines PVFS2_SUPER_MAGIC.

I have an older mpich2-0.96p2 tree that has in
src/mpi/romio/adio/common/ad_fstype.c:

    /* XXX: any way to do this so we don't need the magic number here? */
    #define PVFS2_SUPER_MAGIC 0x20030528

But that has been excised in the 1.0.1 tree.  (And I use this romio
version in our production mpich1 tree.)

It is nowhere in the pvfs2 source either, but we do have a PVFS2_MAGIC
constant deep in a kernel header.

Where should the define live?

		-- Pete