[svn-r761] Changes since 19981013

----------------------

./src/H5.c
	Fixed a signed vs. unsigned comparison.

./src/H5D.c
	Setting a fill value of all zeros will cause the fill value to
	be written to the dataset instead of relying on the low-level
	file driver initializing unwritten areas with zero.

./src/H5D.c
./src/H5F.c
./src/H5Fprivate.h
./src/H5G.c
./src/H5Gpkg.h
./src/H5Gprivate.h
./src/H5O.c
./src/H5T.c
	More file mounting stuff.

./src/H5I.c
	Fixed a bug where trying to close an invalid object id caused
	a core dump.  For instance, H5Gclose(-1).

./MANIFEST
./test/Makefile.in
./test/mount.c		[NEW]
	Mounting tests.

./src/H5R.c
	Fixed a couple (herr_t)NULL casts.

11 files changed, 215 insertions, 85 deletions

diff --git a/src/H5.c b/src/H5.c
index fa6eba3..3fc25d7 100644
--- a/src/H5.c
+++ b/src/H5.c
@@ -1172,7 +1172,7 @@ H5_trace (hbool_t returning, const char *func, const char *type, ...)
     }
 
     /* Clear array sizes */
-    for (i=0; i<NELMTS(asize); i++) asize[i] = -1;
+    for (i=0; i<(hssize_t)NELMTS(asize); i++) asize[i] = -1;
 
     /* Parse the argument types */
     for (argno=0; *type; argno++, type+=HDisupper(*type)?2:1) {
diff --git a/src/H5D.c b/src/H5D.c
index 27b46ca..6f5ca00 100644
--- a/src/H5D.c
+++ b/src/H5D.c
@@ -832,10 +832,12 @@ H5D_new(const H5D_create_t *create_parms)
         HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
 		     "memory allocation failed");
     }
-    if(create_parms!=NULL)
+    if(create_parms!=NULL) {
         ret_value->create_parms = H5P_copy (H5P_DATASET_CREATE, create_parms);
-    else
-        ret_value->create_parms = H5P_copy (H5P_DATASET_CREATE, &H5D_create_dflt);
+    } else {
+        ret_value->create_parms = H5P_copy (H5P_DATASET_CREATE,
+					    &H5D_create_dflt);
+    }
     H5F_addr_undef(&(ret_value->ent.header));
 
     /* Success */
@@ -887,17 +889,28 @@ H5D_create(H5G_entry_t *loc, const char *name, const H5T_t *type,
     intn		i, ndims;
     hsize_t		max_dim[H5O_LAYOUT_NDIMS];
     H5O_efl_t		*efl = NULL;
-    H5F_t		*f = loc->file;
+    H5F_t		*f = NULL;
 
     FUNC_ENTER(H5D_create, NULL);
 
     /* check args */
-    assert (f);
     assert (loc);
     assert (name && *name);
     assert (type);
     assert (space);
     assert (create_parms);
+    if (create_parms->pline.nfilters>0 &&
+	H5D_CHUNKED!=create_parms->layout) {
+	HGOTO_ERROR (H5E_DATASET, H5E_BADVALUE, NULL,
+		     "filters can only be used with chunked layout");
+    }
+
+    /* What file is the dataset being added to? */
+    if (NULL==(f=H5G_insertion_file(loc, name))) {
+	HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL,
+		    "unable to locate insertion point");
+    }
+
 #ifdef HAVE_PARALLEL
     /* If MPIO is used, no filter support yet. */
     if (f->shared->access_parms->driver == H5F_LOW_MPIO &&
@@ -906,12 +919,7 @@ H5D_create(H5G_entry_t *loc, const char *name, const H5T_t *type,
 		     "Parallel IO does not support filters yet");
     }
 #endif
-    if (create_parms->pline.nfilters>0 &&
-	H5D_CHUNKED!=create_parms->layout) {
-	HGOTO_ERROR (H5E_DATASET, H5E_BADVALUE, NULL,
-		     "filters can only be used with chunked layout");
-    }
-
+    
     /* Initialize the dataset object */
     if (NULL==(new_dset = H5D_new(create_parms))) {
         HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
@@ -1118,8 +1126,9 @@ H5D_create(H5G_entry_t *loc, const char *name, const H5T_t *type,
  * Modifications:
  * 	Robb Matzke, 9 Jun 1998
  *	The data space message is no longer cached in the dataset struct.
- *  Quincey Koziol, 12 Oct 1998
- *  Moved guts of function into H5D_open_oid
+ *	
+ *  	Quincey Koziol, 12 Oct 1998
+ *  	Moved guts of function into H5D_open_oid
  *
  *-------------------------------------------------------------------------
  */
@@ -1204,14 +1213,16 @@ H5D_open_oid(H5D_t *dataset, H5G_entry_t *ent)
     }
 
     /* Get the optional fill value message */
-    if (NULL==H5O_read(&(dataset->ent), H5O_FILL, 0, &(dataset->create_parms->fill))) {
+    if (NULL==H5O_read(&(dataset->ent), H5O_FILL, 0,
+		       &(dataset->create_parms->fill))) {
         H5E_clear();
         HDmemset(&(dataset->create_parms->fill), 0,
                 sizeof(dataset->create_parms->fill));
     }
 
     /* Get the optional filters message */
-    if (NULL==H5O_read (&(dataset->ent), H5O_PLINE, 0, &(dataset->create_parms->pline))) {
+    if (NULL==H5O_read (&(dataset->ent), H5O_PLINE, 0,
+			&(dataset->create_parms->pline))) {
         H5E_clear ();
         HDmemset (&(dataset->create_parms->pline), 0,
                 sizeof(dataset->create_parms->pline));
@@ -1219,7 +1230,7 @@ H5D_open_oid(H5D_t *dataset, H5G_entry_t *ent)
 
 #ifdef HAVE_PARALLEL
     /* If MPIO is used, no filter support yet. */
-    if (dataset.ent.file->shared->access_parms->driver == H5F_LOW_MPIO &&
+    if (dataset->ent.file->shared->access_parms->driver == H5F_LOW_MPIO &&
             dataset->create_parms->pline.nfilters>0){
         HGOTO_ERROR (H5E_DATASET, H5E_UNSUPPORTED, FAIL,
 		     "Parallel IO does not support filters yet");
@@ -1255,12 +1266,14 @@ H5D_open_oid(H5D_t *dataset, H5G_entry_t *ent)
             break;
 
         default:
-            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "not implemented yet");
+            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL,
+			"not implemented yet");
     }
 
     /* Get the external file list message, which might not exist */
-    if (NULL==H5O_read (&(dataset->ent), H5O_EFL, 0, &(dataset->create_parms->efl)) &&
-            !H5F_addr_defined (&(dataset->layout.addr))) {
+    if (NULL==H5O_read (&(dataset->ent), H5O_EFL, 0,
+			&(dataset->create_parms->efl)) &&
+	!H5F_addr_defined (&(dataset->layout.addr))) {
         HGOTO_ERROR (H5E_DATASET, H5E_CANTINIT, FAIL,
 		     "storage address is undefined an no external file list");
     }
@@ -1270,7 +1283,8 @@ H5D_open_oid(H5D_t *dataset, H5G_entry_t *ent)
      * This is especially important for parallel I/O where the B-tree must
      * be fully populated before I/O can happen.
      */
-    if ((dataset->ent.file->intent & H5F_ACC_RDWR) && H5D_CHUNKED==dataset->layout.type) {
+    if ((dataset->ent.file->intent & H5F_ACC_RDWR) &&
+	H5D_CHUNKED==dataset->layout.type) {
         if (H5D_init_storage(dataset, space)<0) {
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL,
                 "unable to initialize file storage");
@@ -1831,7 +1845,8 @@ H5D_write(H5D_t *dataset, const H5T_t *mem_type, const H5S_t *mem_space,
      * turns off background preservation.
      */
 #ifdef QAK
-    printf("%s: check 0.5, nelmts=%d, mem_space->rank=%d\n",FUNC,(int)nelmts,mem_space->extent.u.simple.rank);
+    printf("%s: check 0.5, nelmts=%d, mem_space->rank=%d\n", FUNC,
+	   (int)nelmts, mem_space->extent.u.simple.rank);
 #endif /* QAK */
     if (nelmts!=H5S_get_select_npoints (file_space)) {
 	HGOTO_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL,
@@ -2266,8 +2281,7 @@ H5D_init_storage(H5D_t *dset, const H5S_t *space)
     intn		ndims;
     hsize_t		dim[H5O_LAYOUT_NDIMS];
     hsize_t		npoints, ptsperbuf;
-    size_t		i, size, bufsize=8*1024;
-    hbool_t		all_zero;
+    size_t		size, bufsize=8*1024;
     hid_t		buf_id = -1;
     haddr_t		addr;
     herr_t		ret_value = FAIL;
@@ -2280,18 +2294,13 @@ H5D_init_storage(H5D_t *dset, const H5S_t *space)
     switch (dset->layout.type) {
     case H5D_CONTIGUOUS:
 	/*
-	 * If the fill value is non-zero then write the fill value to the
-	 * specified selection.
+	 * If the fill value is set then write it to the specified selection
+	 * even if it is all zero.  This allows the application to force
+	 * filling when the underlying storage isn't initialized to zero.
 	 */
-	for (i=0, all_zero=TRUE; i<dset->create_parms->fill.size; i++) {
-	    if (((uint8*)(dset->create_parms->fill.buf))[i]) {
-		all_zero = FALSE;
-		break;
-	    }
-	}
 	npoints = H5S_get_simple_extent_npoints(space);
-
-	if (!all_zero && npoints==H5S_get_select_npoints(space)) {
+	if (dset->create_parms->fill.buf &&
+	    npoints==H5S_get_select_npoints(space)) {
 	    /*
 	     * Fill the entire current extent with the fill value.  We can do
 	     * this quite efficiently by making sure we copy the fill value
@@ -2330,7 +2339,7 @@ H5D_init_storage(H5D_t *dset, const H5S_t *space)
 		npoints -= MIN(ptsperbuf, npoints);
 		H5F_addr_inc(&addr, size);
 	    }
-	} else if (!all_zero) {
+	} else if (dset->create_parms->fill.buf) {
 	    /*
 	     * Fill the specified selection with the fill value.
 	     */
diff --git a/src/H5F.c b/src/H5F.c
index 9436104..ac5d2fd 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -289,7 +289,7 @@ H5Fget_create_plist(hid_t file_id)
     H5TRACE1("i","i",file_id);
 
     /* check args */
-    if (H5I_FILE != H5I_get_type(file_id) || NULL==(file=H5I_object(file_id))) {
+    if (H5I_FILE!=H5I_get_type(file_id) || NULL==(file=H5I_object(file_id))) {
 	HRETURN_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file");
     }
     
@@ -1535,15 +1535,29 @@ H5F_flush(H5F_t *f, hbool_t invalidate)
 herr_t
 H5F_close(H5F_t *f)
 {
+    uintn	i;
+
     FUNC_ENTER(H5F_close, FAIL);
 
     /*
+     * Find the root of the virtual file. Then unmount and close each child
+     * before closing the current file.
+     */
+    while (f->mtab.parent) f = f->mtab.parent;
+    for (i=0; i<f->mtab.nmounts; i++) {
+	H5G_close(f->mtab.child[i].group);
+	f->mtab.child[i].file->mtab.parent = NULL;
+	H5F_close(f->mtab.child[i].file);
+    }
+    f->mtab.nmounts = 0;
+
+    /*
      * If object headers are still open then delay deletion of resources until
      * they have all been closed.  Flush all caches and update the object
      * header anyway so that failing to close all objects isn't a major
      * problem.
      */
-    if (f->nopen>0) {
+    if (f->nopen_objs>0) {
 	if (H5F_flush(f, FALSE)<0) {
 	    HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
 			  "unable to flush cache");
@@ -1553,9 +1567,9 @@ H5F_close(H5F_t *f)
 	    fprintf(H5DEBUG(F), "H5F: H5F_close(%s): %u object header%s still "
 		    "open (file close will complete when %s closed)\n",
 		    f->name,
-		    f->nopen,
-		    1 == f->nopen ? " is" : "s are",
-		    1 == f->nopen ? "that header is" : "those headers are");
+		    f->nopen_objs,
+		    1 == f->nopen_objs?" is":"s are",
+		    1 == f->nopen_objs?"that header is":"those headers are");
 	}
 #endif
 	f->close_pending = TRUE;
@@ -1942,6 +1956,7 @@ H5F_mountpoint(H5G_entry_t *find/*in,out*/)
 	if (0==cmp) {
 	    ent = H5G_entof(parent->mtab.child[md].file->shared->root_grp);
 	    *find = *ent;
+	    parent = ent->file;
 	}
     } while (!cmp);
     
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 8ba9613..004c411 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -479,7 +479,7 @@ typedef struct H5F_t {
     uintn		intent;		/* The flags passed to H5F_open()*/
     char		*name;		/* Name used to open file	*/
     H5F_file_t		*shared;	/* The shared file info		*/
-    uintn		nopen;		/* Number of open object headers*/
+    uintn		nopen_objs;	/* Number of open object headers*/
     hbool_t		close_pending;	/* File close is pending	*/
     H5F_mtab_t		mtab;		/* File mount table		*/
 } H5F_t;
diff --git a/src/H5G.c b/src/H5G.c
index e2d0e39..90dd1a9 100644
--- a/src/H5G.c
+++ b/src/H5G.c
@@ -427,7 +427,7 @@ H5Glink(hid_t loc_id, H5G_link_t type, const char *cur_name,
 	HRETURN_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL,
 		       "no new name specified");
     }
-    if (H5G_link (loc, type, cur_name, new_name)<0) {
+    if (H5G_link (loc, type, cur_name, new_name, H5G_TARGET_NORMAL)<0) {
 	HRETURN_ERROR (H5E_SYM, H5E_LINK, FAIL, "unable to create link");
     }
 
@@ -839,15 +839,21 @@ H5G_basename(const char *name, size_t *size_p)
  *		understood by this function (unless it appears as an entry in
  *		the symbol table).
  *
- *		Symbolic links are followed automatically, but if
- *		FOLLOW_SLINK is false and the last component of the name is a
- *		symbolic link then that link is not followed.  At most NLINKS
- *		are followed and the next link generates an error.
+ *		Symbolic links are followed automatically, but if TARGET
+ *		includes the H5G_TARGET_SLINK bit and the last component of
+ *		the name is a symbolic link then that link is not followed.
+ *		The *NLINKS value is decremented each time a link is followed
+ *		and link traversal fails if the value would become negative.
+ *		If NLINKS is the null pointer then a default value is used.
  *
  *		Mounted files are handled by calling H5F_mountpoint() after
  *		each step of the translation.  If the input argument to that
  *		function is a mount point then the argument shall be replaced
  *		with information about the root group of the mounted file.
+ *		But if TARGET includes the H5G_TARGET_MOUNT bit and the last
+ *		component of the name is a mount point then H5F_mountpoint()
+ *		is not called and information about the mount point itself is
+ *		returned.
  *		
  * Errors:
  *
@@ -871,7 +877,7 @@ H5G_basename(const char *name, size_t *size_p)
 static herr_t
 H5G_namei(H5G_entry_t *loc_ent, const char *name, const char **rest/*out*/,
 	  H5G_entry_t *grp_ent/*out*/, H5G_entry_t *obj_ent/*out*/,
-	  hbool_t follow_slink, intn *nlinks)
+	  uintn target, intn *nlinks)
 {
     H5G_entry_t		_grp_ent;	/*entry for current group	*/
     H5G_entry_t		_obj_ent;	/*entry found			*/
@@ -944,11 +950,12 @@ H5G_namei(H5G_entry_t *loc_ent, const char *name, const char **rest/*out*/,
 
 	/*
 	 * If we found a symbolic link then we should follow it.  But if this
-	 * is the last component of the name and FOLLOW_SLINK is zero then we
-	 * don't follow it.
+	 * is the last component of the name and the H5G_TARGET_SLINK bit of
+	 * TARGET is set then we don't follow it.
 	 */
 	if (H5G_CACHED_SLINK==obj_ent->type &&
-	    (follow_slink || ((s=H5G_component(name+nchars, NULL)) && *s))) {
+	    (0==(target & H5G_TARGET_SLINK) ||
+	     ((s=H5G_component(name+nchars, NULL)) && *s))) {
 	    if ((*nlinks)-- <= 0) {
 		HRETURN_ERROR (H5E_SYM, H5E_SLINK, FAIL,
 			       "too many symbolic links");
@@ -959,8 +966,17 @@ H5G_namei(H5G_entry_t *loc_ent, const char *name, const char **rest/*out*/,
 	    }
 	}
 
+	/*
+	 * Resolve mount points to the mounted group.  Do not do this step if
+	 * the H5G_TARGET_MOUNT bit of TARGET is set and this is the last
+	 * component of the name.
+	 */
+	if (0==(target & H5G_TARGET_MOUNT) ||
+	    ((s=H5G_component(name+nchars, NULL)) && *s)) {
+	    H5F_mountpoint(obj_ent/*in,out*/);
+	}
+	
 	/* next component */
-	H5F_mountpoint(obj_ent/*in,out*/);
 	name += nchars;
     }
     if (rest) *rest = name; /*final null */
@@ -1014,7 +1030,8 @@ H5G_traverse_slink (H5G_entry_t *grp_ent/*in,out*/,
     linkval = H5MM_xstrdup (clv);
 
     /* Traverse the link */
-    if (H5G_namei (grp_ent, linkval, NULL, grp_ent, obj_ent, TRUE, nlinks)) {
+    if (H5G_namei (grp_ent, linkval, NULL, grp_ent, obj_ent, H5G_TARGET_NORMAL,
+		   nlinks)) {
 	HGOTO_ERROR (H5E_SYM, H5E_NOTFOUND, FAIL,
 		     "unable to follow symbolic link");
     }
@@ -1101,8 +1118,8 @@ H5G_mkroot (H5F_t *f, H5G_entry_t *ent)
     }
     f->shared->root_grp->ent = *ent;
     f->shared->root_grp->nref = 1;
-    assert (1==f->nopen);
-    f->nopen = 0;
+    assert (1==f->nopen_objs);
+    f->nopen_objs = 0;
 
     FUNC_LEAVE(SUCCEED);
 }
@@ -1146,7 +1163,8 @@ H5G_create(H5G_entry_t *loc, const char *name, size_t size_hint)
     assert(name && *name);
 
     /* lookup name */
-    if (0 == H5G_namei(loc, name, &rest, &grp_ent, NULL, TRUE, NULL)) {
+    if (0 == H5G_namei(loc, name, &rest, &grp_ent, NULL, H5G_TARGET_NORMAL,
+		       NULL)) {
 	HRETURN_ERROR(H5E_SYM, H5E_EXISTS, NULL, "already exists");
     }
     H5E_clear(); /*it's OK that we didn't find it */
@@ -1320,11 +1338,15 @@ H5G_close(H5G_t *grp)
 /*-------------------------------------------------------------------------
  * Function:	H5G_rootof
  *
- * Purpose:	Return a pointer to the root group of the file.
+ * Purpose:	Return a pointer to the root group of the file.  If the file
+ *		is part of a virtual file then the root group of the virtual
+ *		file is returned.
  *
- * Return:	Success:	
+ * Return:	Success:	Ptr to the root group of the file.  Do not
+ *				free the pointer -- it points directly into
+ *				the file struct.
  *
- *		Failure:	
+ *		Failure:	NULL
  *
  * Programmer:	Robb Matzke
  *              Tuesday, October 13, 1998
@@ -1336,8 +1358,8 @@ H5G_close(H5G_t *grp)
 H5G_t *
 H5G_rootof(H5F_t *f)
 {
-    
     FUNC_ENTER(H5G_rootof, NULL);
+    while (f->mtab.parent) f = f->mtab.parent;
     FUNC_LEAVE(f->shared->root_grp);
 }
 
@@ -1378,7 +1400,7 @@ H5G_insert(H5G_entry_t *loc, const char *name, H5G_entry_t *ent)
     /*
      * Look up the name -- it shouldn't exist yet.
      */
-    if (H5G_namei(loc, name, &rest, &grp, NULL, TRUE, NULL) >= 0) {
+    if (H5G_namei(loc, name, &rest, &grp, NULL, H5G_TARGET_NORMAL, NULL)>=0) {
 	HRETURN_ERROR(H5E_SYM, H5E_EXISTS, FAIL, "already exists");
     }
     H5E_clear(); /*it's OK that we didn't find it */
@@ -1409,6 +1431,7 @@ H5G_insert(H5G_entry_t *loc, const char *name, H5G_entry_t *ent)
 		      "unable to increment hard link count");
     }
     if (H5G_stab_insert(&grp, rest, ent) < 0) {
+	H5O_link(ent, -1);
 	HRETURN_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to insert name");
     }
     FUNC_LEAVE(SUCCEED);
@@ -1452,7 +1475,8 @@ H5G_find(H5G_entry_t *loc, const char *name,
     assert (loc);
     assert (name && *name);
 
-    if (H5G_namei(loc, name, NULL, grp_ent, obj_ent, TRUE, NULL)<0) {
+    if (H5G_namei(loc, name, NULL, grp_ent, obj_ent, H5G_TARGET_NORMAL,
+		  NULL)<0) {
 	HRETURN_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found");
     }
     FUNC_LEAVE(SUCCEED);
@@ -1650,7 +1674,7 @@ H5G_loc (hid_t loc_id)
  */
 herr_t
 H5G_link (H5G_entry_t *loc, H5G_link_t type, const char *cur_name,
-	  const char *new_name)
+	  const char *new_name, uintn namei_flags)
 {
     H5G_entry_t		cur_obj;	/*entry for the link tail	*/
     H5G_entry_t		grp_ent;	/*ent for grp containing link hd*/
@@ -1673,7 +1697,8 @@ H5G_link (H5G_entry_t *loc, H5G_link_t type, const char *cur_name,
 	 * Lookup the the new_name so we can get the group which will contain
 	 * the new entry.  The entry shouldn't exist yet.
 	 */
-	if (H5G_namei (loc, new_name, &rest, &grp_ent, NULL, TRUE, NULL)>=0) {
+	if (H5G_namei (loc, new_name, &rest, &grp_ent, NULL, H5G_TARGET_NORMAL,
+		       NULL)>=0) {
 	    HRETURN_ERROR (H5E_SYM, H5E_EXISTS, FAIL, "already exists");
 	}
 	H5E_clear (); /*it's okay that we didn't find it*/
@@ -1738,9 +1763,10 @@ H5G_link (H5G_entry_t *loc, H5G_link_t type, const char *cur_name,
 	break;
 
     case H5G_LINK_HARD:
-	if (H5G_find (loc, cur_name, NULL, &cur_obj)<0) {
-	    HRETURN_ERROR (H5E_SYM, H5E_NOTFOUND, FAIL,
-			   "source object not found");
+	if (H5G_namei(loc, cur_name, NULL, NULL, &cur_obj, namei_flags,
+		      NULL)<0) {
+	    HRETURN_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL,
+			  "source object not found");
 	}
 	if (H5G_insert (loc, new_name, &cur_obj)<0) {
 	    HRETURN_ERROR (H5E_SYM, H5E_CANTINIT, FAIL,
@@ -1793,7 +1819,7 @@ H5G_get_objinfo (H5G_entry_t *loc, const char *name, hbool_t follow_link,
 
     /* Find the object's symbol table entry */
     if (H5G_namei (loc, name, NULL, &grp_ent/*out*/, &obj_ent/*out*/,
-		   follow_link, NULL)<0) {
+		   follow_link?H5G_TARGET_NORMAL:H5G_TARGET_SLINK, NULL)<0) {
 	HRETURN_ERROR (H5E_SYM, H5E_NOTFOUND, FAIL, "unable to stat object");
     }
 
@@ -1889,8 +1915,8 @@ H5G_linkval (H5G_entry_t *loc, const char *name, size_t size, char *buf/*out*/)
      * Get the symbol table entry for the link head and the symbol table
      * entry for the group in which the link head appears.
      */
-    if (H5G_namei (loc, name, NULL, &grp_ent/*out*/, &obj_ent/*out*/, FALSE,
-		   NULL)<0) {
+    if (H5G_namei (loc, name, NULL, &grp_ent/*out*/, &obj_ent/*out*/,
+		   H5G_TARGET_SLINK, NULL)<0) {
 	HRETURN_ERROR (H5E_SYM, H5E_NOTFOUND, FAIL,
 		       "symbolic link was not found");
     }
@@ -1947,7 +1973,8 @@ H5G_set_comment(H5G_entry_t *loc, const char *name, const char *buf)
     FUNC_ENTER(H5G_set_comment, FAIL);
 
     /* Get the symbol table entry for the object */
-    if (H5G_namei(loc, name, NULL, NULL, &obj_ent/*out*/, TRUE, NULL)<0) {
+    if (H5G_namei(loc, name, NULL, NULL, &obj_ent/*out*/, H5G_TARGET_NORMAL,
+		  NULL)<0) {
 	HRETURN_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found");
     }
 
@@ -1996,7 +2023,8 @@ H5G_get_comment(H5G_entry_t *loc, const char *name, size_t bufsize, char *buf)
     FUNC_ENTER(H5G_get_comment, FAIL);
 
     /* Get the symbol table entry for the object */
-    if (H5G_namei(loc, name, NULL, NULL, &obj_ent/*out*/, TRUE, NULL)<0) {
+    if (H5G_namei(loc, name, NULL, NULL, &obj_ent/*out*/, H5G_TARGET_NORMAL,
+		  NULL)<0) {
 	HRETURN_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found");
     }
 
@@ -2043,7 +2071,8 @@ H5G_unlink(H5G_entry_t *loc, const char *name)
     assert(name && *name);
 
     /* Get the entry for the group that contains the object to be unlinked */
-    if (H5G_namei(loc, name, NULL, &grp_ent, &obj_ent, FALSE, NULL)<0) {
+    if (H5G_namei(loc, name, NULL, &grp_ent, &obj_ent,
+		  H5G_TARGET_SLINK|H5G_TARGET_MOUNT, NULL)<0) {
 	HRETURN_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found");
     }
     if (!H5F_addr_defined(&(grp_ent.header))) {
@@ -2113,7 +2142,8 @@ H5G_move(H5G_entry_t *loc, const char *src_name, const char *dst_name)
 			      "unable to read symbolic link value");
 	    }
 	} while (linkval[lv_size-1]);
-	if (H5G_link(loc, H5G_LINK_SOFT, linkval, dst_name)<0) {
+	if (H5G_link(loc, H5G_LINK_SOFT, linkval, dst_name,
+		     H5G_TARGET_NORMAL)<0) {
 	    HRETURN_ERROR(H5E_SYM, H5E_CANTINIT, FAIL,
 			  "unable to rename symbolic link");
 	}
@@ -2123,7 +2153,8 @@ H5G_move(H5G_entry_t *loc, const char *src_name, const char *dst_name)
 	/*
 	 * Rename the object.
 	 */
-	if (H5G_link(loc, H5G_LINK_HARD, src_name, dst_name)<0) {
+	if (H5G_link(loc, H5G_LINK_HARD, src_name, dst_name,
+		     H5G_TARGET_MOUNT)<0) {
 	    HRETURN_ERROR(H5E_SYM, H5E_CANTINIT, FAIL,
 			  "unable to register new name for object");
 	}
@@ -2137,3 +2168,55 @@ H5G_move(H5G_entry_t *loc, const char *src_name, const char *dst_name)
 
     FUNC_LEAVE(SUCCEED);
 }
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5G_insertion_file
+ *
+ * Purpose:	Given a location and name that specifies a not-yet-existing
+ *		object return the file into which the object is about to be
+ *		inserted.
+ *
+ * Return:	Success:	File pointer
+ *
+ *		Failure:	NULL
+ *
+ * Programmer:	Robb Matzke
+ *              Wednesday, October 14, 1998
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+H5F_t *
+H5G_insertion_file(H5G_entry_t *loc, const char *name)
+{
+    const char	*rest;
+    H5G_entry_t	grp_ent;
+    size_t	size;
+
+    FUNC_ENTER(H5G_insertion_file, NULL);
+    assert(loc);
+    assert(name && *name);
+
+    /*
+     * Look up the name to get the containing group and to make sure the name
+     * doesn't already exist.
+     */
+    if (H5G_namei(loc, name, &rest, &grp_ent, NULL, H5G_TARGET_NORMAL,
+		  NULL)>=0) {
+	HRETURN_ERROR(H5E_SYM, H5E_EXISTS, NULL, "name already exists");
+    }
+    H5E_clear();
+
+    /* Make sure only the last component wasn't resolved */
+    rest = H5G_component(rest, &size);
+    assert(*rest && size>0);
+    rest = H5G_component(rest+size, NULL);
+    if (*rest) {
+	HRETURN_ERROR(H5E_SYM, H5E_NOTFOUND, NULL,
+		      "insertion point not found");
+    }
+
+    FUNC_LEAVE(grp_ent.file);
+}
diff --git a/src/H5Gpkg.h b/src/H5Gpkg.h
index 74573f3..03a2629 100644
--- a/src/H5Gpkg.h
+++ b/src/H5Gpkg.h
@@ -56,6 +56,15 @@ struct H5G_t {
 };
 
 /*
+ * During name lookups (see H5G_namei()) we sometimes want information about
+ * a symbolic link or a mount point.  The normal operation is to follow the
+ * symbolic link or mount point and return information about its target.
+ */
+#define H5G_TARGET_NORMAL	0x0000
+#define H5G_TARGET_SLINK	0x0001
+#define H5G_TARGET_MOUNT	0x0002
+
+/*
  * These operations can be passed down from the H5G_stab layer to the
  * H5G_node layer through the B-tree layer.
  */
diff --git a/src/H5Gprivate.h b/src/H5Gprivate.h
index 417f011..1cf448f 100644
--- a/src/H5Gprivate.h
+++ b/src/H5Gprivate.h
@@ -109,7 +109,7 @@ H5G_t *H5G_reopen (H5G_t *grp);
 herr_t H5G_close (H5G_t *grp);
 H5G_t *H5G_rootof(H5F_t *f);
 herr_t H5G_link (H5G_entry_t *loc, H5G_link_t type, const char *cur_name,
-		 const char *new_name);
+		 const char *new_name, uintn namei_flags);
 herr_t H5G_get_objinfo (H5G_entry_t *loc, const char *name,
 			hbool_t follow_link, H5G_stat_t *statbuf/*out*/);
 herr_t H5G_linkval (H5G_entry_t *loc, const char *name, size_t size,
@@ -122,6 +122,7 @@ herr_t H5G_move(H5G_entry_t *loc, const char *src_name, const char *dst_name);
 herr_t H5G_unlink(H5G_entry_t *loc, const char *name);
 herr_t H5G_find (H5G_entry_t *loc, const char *name,
 		 H5G_entry_t *grp_ent/*out*/, H5G_entry_t *ent/*out*/);
+H5F_t *H5G_insertion_file(H5G_entry_t *loc, const char *name);
 herr_t H5G_traverse_slink (H5G_entry_t *grp_ent/*in,out*/,
 			   H5G_entry_t *obj_ent/*in,out*/,
 			   intn *nlinks/*in,out*/);
diff --git a/src/H5I.c b/src/H5I.c
index 91c8b1a..6dc7ef3 100644
--- a/src/H5I.c
+++ b/src/H5I.c
@@ -564,8 +564,8 @@ H5I_get_type(hid_t id)
 
     FUNC_ENTER(H5I_get_type, H5I_BADID);
 
-    ret_value = H5I_GROUP(id);
-    assert(ret_value>H5I_BADID && ret_value<H5I_MAXID);
+    if (id>0) ret_value = H5I_GROUP(id);
+    assert(ret_value>=H5I_BADID && ret_value<H5I_MAXID);
 
     FUNC_LEAVE(ret_value);
 }
diff --git a/src/H5O.c b/src/H5O.c
index 233d7f5..4386962 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -244,7 +244,7 @@ H5O_open(H5G_entry_t *obj_ent)
 #endif
 
     /* Increment open-lock counters */
-    obj_ent->file->nopen++;
+    obj_ent->file->nopen_objs++;
     FUNC_LEAVE(SUCCEED);
 }
 
@@ -273,16 +273,16 @@ H5O_close(H5G_entry_t *obj_ent)
     /* Check args */
     assert(obj_ent);
     assert(obj_ent->file);
-    assert(obj_ent->file->nopen > 0);
+    assert(obj_ent->file->nopen_objs > 0);
 
     /* Decrement open-lock counters */
-    --obj_ent->file->nopen;
+    --obj_ent->file->nopen_objs;
 
     /*
      * If the file open-lock count has reached zero and the file has a close
      * pending then close the file.
      */
-    if (0 == obj_ent->file->nopen && obj_ent->file->close_pending) {
+    if (0 == obj_ent->file->nopen_objs && obj_ent->file->close_pending) {
 	H5F_close(obj_ent->file);
     }
 #ifdef H5O_DEBUG
@@ -1203,8 +1203,14 @@ H5O_modify(H5G_entry_t *ent, const H5O_class_t *type, intn overwrite,
 	    } else {
 		/*
 		 * The shared message is stored in some other object header.
-		 * Increment the reference count on that object header.
+		 * The other object header must be in the same file as the
+		 * new object header. Increment the reference count on that
+		 * object header.
 		 */
+		if (sh_mesg->u.ent.file->shared != ent->file->shared) {
+		    HGOTO_ERROR(H5E_OHDR, H5E_LINK, FAIL,
+				"interfile hard links are not allowed");
+		}
 		if (H5O_link (&(sh_mesg->u.ent), 1)<0) {
 		    HGOTO_ERROR (H5E_OHDR, H5E_LINK, FAIL,
 				 "unable to adjust shared object link count");
diff --git a/src/H5R.c b/src/H5R.c
index 88ab707..48051de 100644
--- a/src/H5R.c
+++ b/src/H5R.c
@@ -246,7 +246,7 @@ H5R_dereference(href_t *ref)
      */
     /* Allocate the dataset structure */
     if (NULL==(dataset = H5D_new(NULL))) {
-        HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
+        HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL,
 		     "memory allocation failed");
     }
 
@@ -258,7 +258,7 @@ H5R_dereference(href_t *ref)
 
     /* Open the dataset object */
     if (H5D_open_oid(dataset, &ent) < 0) {
-        HGOTO_ERROR(H5E_DATASET, H5E_NOTFOUND, NULL, "not found");
+        HGOTO_ERROR(H5E_DATASET, H5E_NOTFOUND, FAIL, "not found");
     }
 
     /* Create an atom for the dataset */
diff --git a/src/H5T.c b/src/H5T.c
index 0231a0e..cb72c8c 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -3679,6 +3679,7 @@ herr_t
 H5T_commit (H5G_entry_t *loc, const char *name, H5T_t *type)
 {
     herr_t	ret_value = FAIL;
+    H5F_t	*file = NULL;
     
     FUNC_ENTER (H5T_commit, FAIL);
 
@@ -3699,11 +3700,17 @@ H5T_commit (H5G_entry_t *loc, const char *name, H5T_t *type)
 		       "data type is immutable");
     }
 
+    /* Find the insertion file */
+    if (NULL==(file=H5G_insertion_file(loc, name))) {
+	HRETURN_ERROR(H5E_SYM, H5E_CANTINIT, FAIL,
+		      "unable to find insertion point");
+    }
+
     /*
      * Create the object header and open it for write access. Insert the data
      * type message and then give the object header a name.
      */
-    if (H5O_create (loc->file, 64, &(type->ent))<0) {
+    if (H5O_create (file, 64, &(type->ent))<0) {
 	HGOTO_ERROR (H5E_DATATYPE, H5E_CANTINIT, FAIL,
 		     "unable to create data type object header");
     }