[petsc-dev] HDF5 without H5Pset_fapl_mpio

[Jed Brown]

The current code just charges along if H5Pset_fapl_mpio is not
available, but then H5Fcreate fails because ranks are fighting for a new
file.

  #000: H5F.c line 491 in H5Fcreate(): unable to create file              
    major: File accessibilty                                                       
    minor: Unable to open file                                                                             
  #001: H5Fint.c line 1305 in H5F_open(): unable to lock the file
    major: File accessibilty
    minor: Unable to open file
  #002: H5FD.c line 1839 in H5FD_lock(): driver lock request failed
    major: Virtual File Layer
    minor: Can't update object
  #003: H5FDsec2.c line 940 in H5FD_sec2_lock(): unable to lock file, errno = 11, error message = 'Resource temporarily unavailable'
    major: File accessibilty
    minor: Bad file ID accessed

Seems to me that if the size of the communicator is 1, we shouldn't
bother trying H5Pset_fapl_mpio and if the comm is larger than 1, we need
to *fail* with a sensible error message if H5Pset_fapl_mpio is not
available.  Does that sound right to the people that use HDF5 more
heavily?

  #if defined(PETSC_HAVE_H5PSET_FAPL_MPIO)
    PetscStackCallHDF5(H5Pset_fapl_mpio,(plist_id, PetscObjectComm((PetscObject)viewer), info));
  #endif
    /* Create or open the file collectively */
    switch (hdf5->btype) {
    case FILE_MODE_READ:
      PetscStackCallHDF5Return(hdf5->file_id,H5Fopen,(name, H5F_ACC_RDONLY, plist_id));
      break;
    case FILE_MODE_APPEND:
      PetscStackCallHDF5Return(hdf5->file_id,H5Fopen,(name, H5F_ACC_RDWR, plist_id));
      break;
    case FILE_MODE_WRITE:
      PetscStackCallHDF5Return(hdf5->file_id,H5Fcreate,(name, H5F_ACC_TRUNC, H5P_DEFAULT, plist_id));
      break;
    default:
      SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ORDER, "Must call PetscViewerFileSetMode() before PetscViewerFileSetName()");
    }