[svn-r13465] Description:

	Fix bug in external links when "strong" file close degree is used.

	Make external link callbacks use standard error reporting mechanisms.

	Other minor code cleanups...

Tested on:
	Mac OS X/32 10.4.8 (amazon)
	FreeBSD/32 6.2 (duty)

11 files changed, 398 insertions, 185 deletions

diff --git a/src/H5F.c b/src/H5F.c
index fd8dc24..bd51aa9 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -972,27 +972,6 @@ done:
  *		matzke@llnl.gov
  *		Jul 18 1997
  *
- * Modifications:
- *
- * 	Robb Matzke, 1998-10-14
- *	Nothing happens unless the reference count for the H5F_t goes to
- *	zero.  The reference counts are decremented here.
- *
- * 	Robb Matzke, 1999-02-19
- *	More careful about decrementing reference counts so they don't go
- *	negative or wrap around to some huge value.  Nothing happens if a
- *	reference count is already zero.
- *
- *      Robb Matzke, 2000-10-31
- *      H5FL_FREE() aborts if called with a null pointer (unlike the
- *      original H5MM_free()).
- *
- *      Pedro Vicente, <pvn@ncsa.uiuc.edu> 18 Sep 2002
- *      Added `id to name' support.
- *
- *      James Laird, 2007-1-29
- *      H5F_dest now frees superblock extension oloc.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1004,6 +983,7 @@ H5F_dest(H5F_t *f, hid_t dxpl_id)
 
     /* Sanity check */
     HDassert(f);
+    HDassert(f->shared);
 
     if(1 == f->shared->nrefs) {
         /* Flush at this point since the file will be closed */
@@ -1085,6 +1065,7 @@ H5F_dest(H5F_t *f, hid_t dxpl_id)
     f->mtab.nalloc = 0;
     if(H5FO_top_dest(f) < 0)
         HDONE_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "problems closing file")
+    f->shared = NULL;
     H5FL_FREE(H5F_t, f);
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1566,9 +1547,8 @@ H5Fopen(const char *filename, unsigned flags, hid_t fapl_id)
     new_file->file_id = ret_value;
 
 done:
-    if(ret_value < 0 && new_file)
-        if(H5F_close(new_file) < 0)
-            HDONE_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "problems closing file")
+    if(ret_value < 0 && new_file && H5F_try_close(new_file) < 0)
+        HDONE_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "problems closing file")
 
     FUNC_LEAVE_API(ret_value)
 } /* end H5Fopen() */
@@ -1674,50 +1654,6 @@ done:
  *		matzke@llnl.gov
  *		Aug 29 1997
  *
- * Modifications:
- *              rky 1998-08-28
- *		Only p0 writes metadata to disk.
- *
- * 		Robb Matzke, 1998-10-16
- *		Added the `scope' argument to indicate what should be
- *		flushed. If the value is H5F_SCOPE_GLOBAL then the entire
- *		virtual file is flushed; a value of H5F_SCOPE_LOCAL means
- *		that only the specified file is flushed.  A value of
- *		H5F_SCOPE_DOWN means flush the specified file and all
- *		children.
- *
- * 		Robb Matzke, 1999-08-02
- *		If ALLOC_ONLY is non-zero then all this function does is
- *		allocate space for the userblock and superblock. Also
- *		rewritten to use the virtual file layer.
- *
- * 		Robb Matzke, 1999-08-16
- *		The driver information block is encoded and either allocated
- *		or written to disk.
- *
- *		Raymond Lu, 2001-10-14
- *              Changed to new generic property list.
- *
- *		Quincey Koziol, 2002-05-20
- *              Added 'closing' parameter
- *
- *		Quincey Koziol, 2002-06-05
- *              Added boot block & driver info block checksumming, to avoid
- *              writing them out when they haven't changed.
- *
- *		Quincey Koziol, 2002-06-06
- *              Return the remainders of the metadata & "small data" blocks to
- *              the free list of blocks for the file.
- *
- *              Bill Wendling, 2003-03-18
- *              Modified the flags being passed in to be one flag instead
- *              of several.
- *
- *		John Mainzer, 2005-01-07
- *		H5AC (and H5C) now have their own system of flags.  Hence
- *		we must now translate between the H5F_FLUSH flags and the
- *		H5AC flags.  Added code to handle this detail.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1835,19 +1771,6 @@ done:
  * Programmer:	Robb Matzke
  *		Tuesday, September 23, 1997
  *
- * Modifications:
- * 		Robb Matzke, 1998-10-14
- *		Nothing happens unless the H5F_t reference count is one (the
- *		file is flushed anyway).  The reference count is decremented
- *		by H5F_dest().
- *
- * 		Robb Matzke, 1999-08-02
- *		Modified to use the virtual file layer.
- *
- *		Bill Wendling, 2003-03-18
- *		Modified H5F_flush call to take one flag instead of
- *		several Boolean flags.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1919,6 +1842,7 @@ H5F_try_close(H5F_t *f)
 
     /* Sanity check */
     HDassert(f);
+    HDassert(f->shared);
 
     /* Check if this file is already in the process of closing */
     if(f->closing)
@@ -2903,6 +2827,88 @@ H5F_use_latest_format(const H5F_t *f)
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5F_get_fc_degree
+ *
+ * Purpose:	Retrieve the 'file close degree' for the file.
+ *
+ * Return:	Success:	Non-negative, the 'file close degree'
+ *
+ * 		Failure:	(can't happen)
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Mar  5 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+H5F_close_degree_t
+H5F_get_fc_degree(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOFUNC here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_get_fc_degree)
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->fc_degree)
+} /* end H5F_get_fc_degree() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_incr_nopen_objs
+ *
+ * Purpose:	Increment the number of open objects for a file.
+ *
+ * Return:	Success:	The number of open objects, after the increment
+ *
+ * 		Failure:	(can't happen)
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Mar  6 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+unsigned
+H5F_incr_nopen_objs(H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOFUNC here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_incr_nopen_objs)
+
+    HDassert(f);
+
+    FUNC_LEAVE_NOAPI(++f->nopen_objs)
+} /* end H5F_incr_nopen_objs() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_decr_nopen_objs
+ *
+ * Purpose:	Decrement the number of open objects for a file.
+ *
+ * Return:	Success:	The number of open objects, after the decrement
+ *
+ * 		Failure:	(can't happen)
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Mar  6 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+unsigned
+H5F_decr_nopen_objs(H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOFUNC here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_decr_nopen_objs)
+
+    HDassert(f);
+
+    FUNC_LEAVE_NOAPI(--f->nopen_objs)
+} /* end H5F_decr_nopen_objs() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5F_block_read
  *
  * Purpose:	Reads some data from a file/server/etc into a buffer.
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index e8df026..616bb81 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -162,7 +162,6 @@ H5FL_EXTERN(H5F_file_t);
 
 /* General routines */
 H5_DLL herr_t H5F_init(void);
-H5_DLL herr_t H5F_try_close(H5F_t *f);
 H5_DLL haddr_t H5F_locate_signature(H5FD_t *file, hid_t dxpl_id);
 
 /* File mount related routines */
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 1084ab5..264218f 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -255,7 +255,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_RDCC_NBYTES(F)      ((F)->shared->rdcc_nbytes)
 #define H5F_RDCC_W0(F)          ((F)->shared->rdcc_w0)
 /* Check for file driver feature enabled */
-#define H5F_HAS_FEATURE(F,FL)   ((F)->shared->lf->feature_flags&(FL))
+#define H5F_HAS_FEATURE(F,FL)   ((F)->shared->lf->feature_flags & (FL))
 /* B-tree node raw page */
 #define H5F_GRP_BTREE_SHARED(F) ((F)->shared->grp_btree_shared)
 /* Base address of file */
@@ -265,6 +265,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_GC_REF(F)           ((F)->shared->gc_ref)
 #define H5F_USE_LATEST_FORMAT(F) ((F)->shared->latest_format)
 #define H5F_INTENT(F)           ((F)->intent)
+#define H5F_GET_FC_DEGREE(F)    ((F)->shared->fc_degree)
 #else /* H5F_PACKAGE */
 #define H5F_FCPL(F)             (H5F_get_fcpl(F))
 #define H5F_SIZEOF_ADDR(F)      (H5F_sizeof_addr(F))
@@ -281,6 +282,7 @@ typedef struct H5F_t H5F_t;
 #define H5F_GC_REF(F)           (H5F_gc_ref(F))
 #define H5F_USE_LATEST_FORMAT(F) (H5F_use_latest_format(F))
 #define H5F_INTENT(F)           (H5F_get_intent(F))
+#define H5F_GET_FC_DEGREE(F)    (H5F_get_fc_degree(F))
 #endif /* H5F_PACKAGE */
 
 
@@ -405,6 +407,7 @@ struct H5RC_t;
 /* Private functions */
 H5_DLL H5F_t *H5F_open(const char *name, unsigned flags, hid_t fcpl_id,
     hid_t fapl_id, hid_t dxpl_id);
+H5_DLL herr_t H5F_try_close(H5F_t *f);
 
 /* Functions than retrieve values from the file struct */
 H5_DLL hid_t H5F_get_driver_id(const H5F_t *f);
@@ -421,6 +424,8 @@ H5_DLL int H5F_mpi_get_rank(const H5F_t *f);
 H5_DLL MPI_Comm H5F_mpi_get_comm(const H5F_t *f);
 H5_DLL int H5F_mpi_get_size(const H5F_t *f);
 #endif /* H5_HAVE_PARALLEL */
+H5_DLL unsigned H5F_incr_nopen_objs(H5F_t *f);
+H5_DLL unsigned H5F_decr_nopen_objs(H5F_t *f);
 
 /* Functions than check file mounting information */
 H5_DLL hbool_t H5F_is_mount(const H5F_t *file);
@@ -440,6 +445,7 @@ H5_DLL struct H5RC_t *H5F_grp_btree_shared(const H5F_t *f);
 H5_DLL size_t H5F_sieve_buf_size(const H5F_t *f);
 H5_DLL unsigned H5F_gc_ref(const H5F_t *f);
 H5_DLL hbool_t H5F_use_latest_format(const H5F_t *f);
+H5_DLL H5F_close_degree_t H5F_get_fc_degree(const H5F_t *f);
 
 /* Functions that operate on blocks of bytes wrt super block */
 H5_DLL herr_t H5F_block_read(const H5F_t *f, H5FD_mem_t type, haddr_t addr,
diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index 547502d..0df22bb 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -613,8 +613,8 @@ H5F_super_read(H5F_t *f, hid_t dxpl_id, H5G_loc_t *root_loc)
             H5O_msg_reset(H5O_DRVINFO_ID, &drvinfo);
         } /* end else */
 
-        /* Close the extension.  Bump the version number to avoid closing the
-         * file (since this will be the only open object).
+        /* Close the extension.  Twiddle the number of open objects to avoid
+         * closing the file (since this will be the only open object).
          */
         f->nopen_objs++;
         if(H5O_close(&ext_loc) < 0)
diff --git a/src/H5Gloc.c b/src/H5Gloc.c
index d447d20..247f185 100644
--- a/src/H5Gloc.c
+++ b/src/H5Gloc.c
@@ -133,23 +133,13 @@ H5G_loc(hid_t loc_id, H5G_loc_t *loc)
             {
                 H5F_t	*f;
 
+                /* Get the file struct */
                 if(NULL == (f = H5I_object(loc_id)))
                     HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file ID")
-                if(NULL == (loc->oloc = H5G_oloc(H5G_rootof(f))))
-                    HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get object location for root group")
-                if(NULL == (loc->path = H5G_nameof(H5G_rootof(f))))
-                    HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get path for root group")
-
-                /* Patch up root group's object location to reflect this file */
-                /* (Since the root group info is only stored once for files which
-                 *  share an underlying low-level file)
-                 */
-                /* (but only for non-mounted files) */
-                if(!H5F_is_mount(f))
-                {
-                    loc->oloc->file = f;
-                    loc->oloc->holding_file = FALSE;
-                }
+
+                /* Construct a group location for root group of the file */
+                if(H5G_loc_root(f, loc) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, FAIL, "unable to create location for file")
             } /* end case */
             break;
 
@@ -230,6 +220,56 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5G_loc_root
+ *
+ * Purpose:	Construct a "group location" for the root group of a file
+ *
+ * Return:	Success:	Non-negative
+ * 		Failure:	Negative
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Mar  5 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5G_loc_root(H5F_t *f, H5G_loc_t *loc)
+{
+    H5G_t *root_grp;                    /* Pointer to root group's info */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(H5G_loc_root, FAIL)
+
+    HDassert(f);
+    HDassert(loc);
+
+    /* Retrieve the root group for the file */
+    root_grp = H5G_rootof(f);
+    HDassert(root_grp);
+
+    /* Build the group location for the root group */
+    if(NULL == (loc->oloc = H5G_oloc(root_grp)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get object location for root group")
+    if(NULL == (loc->path = H5G_nameof(root_grp)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get path for root group")
+
+    /* Patch up root group's object location to reflect this file */
+    /* (Since the root group info is only stored once for files which
+     *  share an underlying low-level file)
+     */
+    /* (but only for non-mounted files) */
+    if(!H5F_is_mount(f)) {
+        loc->oloc->file = f;
+        loc->oloc->holding_file = FALSE;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5G_loc_root() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5G_loc_copy
  *
  * Purpose:	Copy over information for a location
diff --git a/src/H5Gpkg.h b/src/H5Gpkg.h
index b02155d..181d5e4 100644
--- a/src/H5Gpkg.h
+++ b/src/H5Gpkg.h
@@ -533,6 +533,7 @@ H5_DLL H5RS_str_t *H5G_build_fullpath_refstr_str(H5RS_str_t *path_r, const char
 /*
  * These functions operate on group "locations"
  */
+H5_DLL herr_t H5G_loc_root(H5F_t *f, H5G_loc_t *loc);
 H5_DLL herr_t H5G_loc_copy(H5G_loc_t *dst, const H5G_loc_t *src, H5_copy_depth_t depth);
 H5_DLL herr_t H5G_loc_insert(H5G_loc_t *grp_loc, const char *name,
     H5G_loc_t *obj_loc, hid_t dxpl_id);
diff --git a/src/H5I.c b/src/H5I.c
index 771e45d..195bb38 100644
--- a/src/H5I.c
+++ b/src/H5I.c
@@ -2077,15 +2077,11 @@ H5I_get_file_id(hid_t obj_id)
         if(H5I_inc_ref(ret_value) < 0)
             HGOTO_ERROR(H5E_ATOM, H5E_CANTSET, FAIL, "incrementing file ID failed")
     }
-    else if(type == H5I_DATATYPE) {
+    else if(type == H5I_DATATYPE || type == H5I_GROUP || type == H5I_DATASET || type == H5I_ATTR) {
         if(H5G_loc(obj_id, &loc) < 0)
-            HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, FAIL, "not a named datatype")
-        ret_value = H5F_get_id(loc.oloc->file);
-    }
-    else if(type == H5I_GROUP || type == H5I_DATASET || type == H5I_ATTR) {
-        if(H5G_loc(obj_id, &loc) < 0)
-            HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, FAIL, "can't get symbol table info")
-        ret_value = H5F_get_id(loc.oloc->file);
+            HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, FAIL, "can't get object location")
+        if((ret_value = H5F_get_id(loc.oloc->file)) < 0)
+            HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, FAIL, "can't get file ID")
     }
     else
         HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "invalid object ID")
diff --git a/src/H5Lexternal.c b/src/H5Lexternal.c
index 5357f6a..074cb47 100644
--- a/src/H5Lexternal.c
+++ b/src/H5Lexternal.c
@@ -13,19 +13,20 @@
  * access to either file, you may request a copy from help@hdfgroup.org.     *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-#define H5L_PACKAGE		/*suppress error about including H5Lpkg   */
 #define H5G_PACKAGE		/*suppress error about including H5Gpkg   */
+#define H5L_PACKAGE		/*suppress error about including H5Lpkg   */
 
 /* Interface initialization */
 #define H5_INTERFACE_INIT_FUNC	H5L_init_extern_interface
 
 #include "H5private.h"          /* Generic Functions                    */
-#include "H5Lpkg.h"             /* Links                                */
 #include "H5Eprivate.h"         /* Error handling                       */
+#include "H5Gpkg.h"             /* Groups                               */
+#include "H5Iprivate.h"		/* IDs					*/
+#include "H5Lpkg.h"             /* Links                                */
 #include "H5MMprivate.h"        /* Memory management                    */
 #include "H5Opublic.h"         /* File objects                         */
-#include "H5Ppublic.h"         /* Property lists                       */
-#include "H5Gpkg.h"             /* Groups                               */
+#include "H5Pprivate.h"         /* Property lists                       */
 
 static hid_t H5L_extern_traverse(const char UNUSED *link_name, hid_t cur_group,
     void * udata, size_t UNUSED udata_size, hid_t lapl_id);
@@ -92,74 +93,117 @@ static hid_t
 H5L_extern_traverse(const char UNUSED *link_name, hid_t cur_group,
     void * udata, size_t UNUSED udata_size, hid_t lapl_id)
 {
-    hid_t         fid;
-    char         *file_name;
-    char         *obj_name;
-    ssize_t       prefix_len;           /* External link prefix length */
-    size_t        fname_len;
-    hbool_t       fname_alloc = FALSE;
-    unsigned      intent;
-    hid_t         fapl_id;
-    hid_t         ret_value = -1;
-
-    file_name = (char *) udata;
+    H5P_genplist_t *plist;              /* Property list pointer */
+    char       *my_prefix;              /* Library's copy of the prefix */
+    H5G_loc_t   root_loc;               /* Location of root group in external file */
+    H5G_loc_t   loc;                    /* Location of object */
+    H5F_t	*ext_file = NULL;	/* File struct for external file */
+    char       *file_name = (char *)udata;
+    char       *obj_name;
+    size_t      fname_len;
+    hbool_t     fname_alloc = FALSE;
+    unsigned    intent;
+    hid_t       fapl_id = -1;
+    hid_t       ret_value = -1;
+
+    FUNC_ENTER_NOAPI(H5L_extern_traverse, FAIL)
+
+    /* Sanity checks */
+    HDassert(file_name);
+
+    /* Gather some information from the external link's user data */
     fname_len = HDstrlen(file_name);
-    obj_name = ((char *) udata) + fname_len + 1;
+    obj_name = ((char *)udata) + fname_len + 1;
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(lapl_id, H5P_LINK_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get the current prefix */
+    if(H5P_get(plist, H5L_ACS_ELINK_PREFIX_NAME, &my_prefix) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get external link prefix")
 
-    /* See if the external link prefix property is set */
-    if((prefix_len = H5Pget_elink_prefix(lapl_id, NULL, (size_t)0)) < 0)
-        goto error;
+    /* Check for prefix being set, if so, prepend it to the filename */
+    if(my_prefix) {
+        size_t prefix_len = HDstrlen(my_prefix);
 
-    /* If so, prepend it to the filename */
-    if(prefix_len > 0)
-    {
         /* Allocate a buffer to hold the filename plus prefix */
-        file_name = H5MM_malloc(prefix_len + fname_len + 1);
+        if(NULL == (file_name = H5MM_malloc(prefix_len + fname_len + 1)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate filename buffer")
         fname_alloc = TRUE;
 
         /* Copy the prefix into the buffer */
-        if(H5Pget_elink_prefix(lapl_id, file_name, (size_t)(prefix_len + 1)) < 0)
-            goto error;
+        HDstrcpy(file_name, my_prefix);
 
         /* Add the external link's filename to the prefix supplied */
         HDstrcat(file_name, udata);
-    }
+    } /* end if */
+
+    /* Get the location for the group holding the external link */
+    if(H5G_loc(cur_group, &loc) < 0)
+        HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't get object location")
 
     /* Whatever access properties and intent the user used on the old file,
      * use the same ones to open the new file.  If this is a bad default,
      * users can override this callback using H5Lregister.
      */
-    if((fid = H5Iget_file_id(cur_group)) < 0)
-        goto error;
-    if(H5Fget_intent(fid, &intent) < 0)
-        goto error;
-    if((fapl_id = H5Fget_access_plist(fid)) < 0)
-        goto error;
-    if(H5Fclose(fid) < 0)
-        goto error;
-
-    if((fid = H5Fopen(file_name, intent, fapl_id)) < 0)
-        goto error;
-
-    ret_value = H5Oopen(fid, obj_name, lapl_id); /* If this fails, our return value will be negative. */
-    if(H5Pclose(fapl_id) < 0)
-        goto error;
-    if(H5Fclose(fid) < 0)
-        goto error;
+    intent = H5F_INTENT(loc.oloc->file);
+    if((fapl_id = H5F_get_access_plist(loc.oloc->file)) < 0)
+        HGOTO_ERROR(H5E_LINK, H5E_CANTGET, FAIL, "can't get file access property list")
+
+    /* Check for non-"weak" file close degree for parent file */
+    if(H5F_GET_FC_DEGREE(loc.oloc->file) != H5F_CLOSE_WEAK) {
+        H5P_genplist_t *fa_plist;      /* Property list pointer */
+        H5F_close_degree_t fc_degree = H5F_CLOSE_WEAK;  /* File close degree */
+
+        /* Get the plist structure */
+        if(NULL == (fa_plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+        /* Set file close degree for new file to "weak" */
+        if(H5P_set(fa_plist, H5F_ACS_CLOSE_DEGREE_NAME, &fc_degree) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file close degree")
+    } /* end if */
+
+    /* Open the external file */
+    /* (extra work with file intent to mask off inappropriate flags) */
+    if(NULL == (ext_file = H5F_open(file_name, ((intent & H5F_ACC_RDWR) ? H5F_ACC_RDWR : H5F_ACC_RDONLY), H5P_FILE_CREATE_DEFAULT, fapl_id, H5AC_dxpl_id)))
+	HGOTO_ERROR(H5E_LINK, H5E_CANTOPENFILE, FAIL, "unable to open external file")
+
+    /* Increment the number of open objects, to hold the file open */
+    H5F_incr_nopen_objs(ext_file);
+
+    /* Retrieve the "group location" for the file's root group */
+    if(H5G_loc_root(ext_file, &root_loc) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, FAIL, "unable to create location for file")
+
+    /* Open the object referenced in the external file */
+    if((ret_value = H5O_open_name(&root_loc, obj_name, lapl_id)) < 0) {
+        H5F_decr_nopen_objs(ext_file);
+        HGOTO_ERROR(H5E_SYM, H5E_CANTOPENOBJ, FAIL, "unable to open object")
+    } /* end if */
+
+    /* Decrement the number of open objects, to let the file close */
+    H5F_decr_nopen_objs(ext_file);
+
+    /* Close the external file */
+    if(H5F_try_close(ext_file) < 0)
+        HGOTO_ERROR(H5E_LINK, H5E_CANTCLOSEFILE, FAIL, "problem closing external file")
+    ext_file = NULL;
 
-    /* Free file_name if it's been allocated */
-    if(fname_alloc)
-        H5MM_xfree(file_name);
-
-    return ret_value;
+done:
+    /* Release resources */
+    if(fapl_id > 0 && H5I_dec_ref(fapl_id) < 0)
+        HDONE_ERROR(H5E_ATOM, H5E_CANTRELEASE, FAIL, "unable to close atom for file access property list")
+    if(ext_file && H5F_try_close(ext_file) < 0)
+        HDONE_ERROR(H5E_LINK, H5E_CANTCLOSEFILE, FAIL, "problem closing external file")
 
-error:
     /* Free file_name if it's been allocated */
     if(fname_alloc)
         H5MM_xfree(file_name);
 
-    return -1;
-}
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5L_extern_traverse() */
 
 
 /*-------------------------------------------------------------------------
@@ -183,18 +227,20 @@ static ssize_t
 H5L_extern_query(const char UNUSED * link_name, void * udata,
     size_t udata_size, void * buf /*out*/, size_t buf_size)
 {
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5L_extern_query)
+
     /* If the buffer is NULL, skip writing anything in it and just return
      * the size needed */
     if(buf) {
         if(udata_size < buf_size)
             buf_size = udata_size;
 
-        /* Copy the udata verbatim up to buf_size*/
+        /* Copy the udata verbatim up to buf_size */
         HDmemcpy(buf, udata, buf_size);
-    }
+    } /* end if */
 
-    return udata_size;
-}
+    FUNC_LEAVE_NOAPI(udata_size)
+} /* end H5L_extern_query() */
 
 
 /*-------------------------------------------------------------------------
@@ -254,7 +300,7 @@ H5Lcreate_external(const char *file_name, const char *obj_name,
 done:
     if(temp_name != NULL)
         H5MM_free(temp_name);
-    FUNC_LEAVE_API(ret_value);
+    FUNC_LEAVE_API(ret_value)
 } /* end H5Lcreate_external() */
 
 
diff --git a/src/H5O.c b/src/H5O.c
index 874b4c8..ca740de 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -195,10 +195,6 @@ hid_t
 H5Oopen(hid_t loc_id, const char *name, hid_t lapl_id)
 {
     H5G_loc_t	loc;
-    H5G_loc_t   obj_loc;                /* Location used to open group */
-    H5G_name_t  obj_path;            	/* Opened object group hier. path */
-    H5O_loc_t   obj_oloc;            	/* Opened object object location */
-    hbool_t     loc_found = FALSE;      /* Entry at 'name' found */
     hid_t       ret_value = FAIL;
 
     FUNC_ENTER_API(H5Oopen, FAIL)
@@ -210,25 +206,11 @@ H5Oopen(hid_t loc_id, const char *name, hid_t lapl_id)
     if(!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")
 
-    /* Set up opened group location to fill in */
-    obj_loc.oloc = &obj_oloc;
-    obj_loc.path = &obj_path;
-    H5G_loc_reset(&obj_loc);
-
-    /* Find the object's location */
-    if(H5G_loc_find(&loc, name, &obj_loc/*out*/, lapl_id, H5AC_dxpl_id) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
-    loc_found = TRUE;
-
     /* Open the object */
-    if((ret_value = H5O_open_by_loc(&obj_loc, H5AC_dxpl_id)) < 0)
+    if((ret_value = H5O_open_name(&loc, name, lapl_id)) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTOPENOBJ, FAIL, "unable to open object")
 
 done:
-    if(ret_value < 0 && loc_found)
-        if(H5G_loc_free(&obj_loc) < 0)
-            HDONE_ERROR(H5E_SYM, H5E_CANTRELEASE, FAIL, "can't free location")
-
     FUNC_LEAVE_API(ret_value)
 } /* end H5Oopen() */
 
@@ -817,6 +799,57 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5O_open_name
+ *
+ * Purpose:	Opens an object within an HDF5 file.
+ *
+ * Return:	Success:	An open object identifier
+ *		Failure:	Negative
+ *
+ * Programmer:	Quincey Koziol
+ *		March  5 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5O_open_name(H5G_loc_t *loc, const char *name, hid_t lapl_id)
+{
+    H5G_loc_t   obj_loc;                /* Location used to open group */
+    H5G_name_t  obj_path;            	/* Opened object group hier. path */
+    H5O_loc_t   obj_oloc;            	/* Opened object object location */
+    hbool_t     loc_found = FALSE;      /* Entry at 'name' found */
+    hid_t       ret_value = FAIL;
+
+    FUNC_ENTER_NOAPI(H5O_open_name, FAIL)
+
+    /* Check args */
+    HDassert(loc);
+    HDassert(name && *name);
+
+    /* Set up opened group location to fill in */
+    obj_loc.oloc = &obj_oloc;
+    obj_loc.path = &obj_path;
+    H5G_loc_reset(&obj_loc);
+
+    /* Find the object's location */
+    if(H5G_loc_find(loc, name, &obj_loc/*out*/, lapl_id, H5AC_dxpl_id) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
+    loc_found = TRUE;
+
+    /* Open the object */
+    if((ret_value = H5O_open_by_loc(&obj_loc, H5AC_dxpl_id)) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTOPENOBJ, FAIL, "unable to open object")
+
+done:
+    if(ret_value < 0 && loc_found)
+        if(H5G_loc_free(&obj_loc) < 0)
+            HDONE_ERROR(H5E_SYM, H5E_CANTRELEASE, FAIL, "can't free location")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_open_name() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5O_open_by_loc
  *
  * Purpose:	Opens an object and returns an ID given its group loction.
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index c08b97d..3fb2255 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -435,6 +435,7 @@ H5_DLL herr_t H5O_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr);
 H5_DLL herr_t H5O_get_info(H5O_loc_t *oloc, H5O_info_t *oinfo, hid_t dxpl_id);
 H5_DLL herr_t H5O_obj_type(const H5O_loc_t *loc, H5O_type_t *obj_type, hid_t dxpl_id);
 H5_DLL herr_t H5O_get_create_plist(const H5O_loc_t *loc, hid_t dxpl_id, struct H5P_genplist_t *oc_plist);
+H5_DLL hid_t H5O_open_name(H5G_loc_t *loc, const char *name, hid_t lapl_id);
 
 /* Object header message routines */
 H5_DLL herr_t H5O_msg_create(const H5O_loc_t *loc, unsigned type_id, unsigned mesg_flags,
diff --git a/test/links.c b/test/links.c
index 6b7e5b2..813b232 100644
--- a/test/links.c
+++ b/test/links.c
@@ -2367,7 +2367,7 @@ external_link_toomany(hid_t fapl, hbool_t new_format)
     } H5E_END_TRY;
     if (gid >= 0) {
 	H5_FAILED();
-	puts("    Should have failed for sequence of too many nested links.");
+	printf("%d:    Should have failed for sequence of too many nested links.", __LINE__);
 	goto error;
     }
 
@@ -3531,7 +3531,7 @@ error:
     return -1;
 }
 
-
+
 /*-------------------------------------------------------------------------
  * Function:    ext_link_endian
  *
@@ -3621,6 +3621,90 @@ error:
     } H5E_END_TRY;
     return -1;
 }
+
+
+/*-------------------------------------------------------------------------
+ * Function:    external_link_strong
+ *
+ * Purpose:     Check that external links work properly when they opened in
+ *              a file with "strong" file close degree.
+ *
+ * Return:      Success:        0
+ *              Failure:        -1
+ *
+ * Programmer:  Quincey Koziol
+ *              Monday, March 5, 2007
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+external_link_strong(hid_t fapl, hbool_t new_format)
+{
+    hid_t       my_fapl;                        /* File access property list */
+    hid_t       fid1 = (-1), fid2 = (-1);       /* File ID */
+    hid_t       gid1 = (-1), gid2 = (-1);       /* Group IDs */
+    char        objname[NAME_BUF_SIZE];         /* Object name */
+    ssize_t     name_len;                       /* Length of object name */
+    char	filename1[NAME_BUF_SIZE],
+                filename2[NAME_BUF_SIZE];
+
+    if(new_format)
+        TESTING("that external files work with strong file close degree (w/new group format)")
+    else
+        TESTING("that external files work with strong file close degree")
+
+    /* Set up filenames */
+    h5_fixname(FILENAME[0], fapl, filename1, sizeof filename1);
+    h5_fixname(FILENAME[1], fapl, filename2, sizeof filename2);
+
+    /* Copy file access property list */
+    if((my_fapl = H5Pcopy(fapl)) < 0) TEST_ERROR
+
+    /* Set strong file close degree */
+    if(H5Pset_fclose_degree(my_fapl, H5F_CLOSE_STRONG) < 0) TEST_ERROR
+
+    /* Create a group at /A/B/C in first file */
+    if((fid1 = H5Fcreate(filename1, H5F_ACC_TRUNC, H5P_DEFAULT, my_fapl)) < 0) TEST_ERROR
+    if((gid1 = H5Gcreate(fid1, "A", (size_t)0)) < 0) TEST_ERROR
+    if(H5Gclose(gid1) < 0) TEST_ERROR
+    if((gid1 = H5Gcreate(fid1, "A/B", (size_t)0)) < 0) TEST_ERROR
+    if(H5Gclose(gid1) < 0) TEST_ERROR
+    if((gid1 = H5Gcreate(fid1, "A/B/C", (size_t)0)) < 0) TEST_ERROR
+    if(H5Gclose(gid1) < 0) TEST_ERROR
+    if(H5Fclose(fid1) < 0) TEST_ERROR
+
+    /* Create an external link /W/X/DLINK in second file to <filename1>:/A/B/C */
+    if((fid2 = H5Fcreate(filename2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0) TEST_ERROR
+    if((gid2 = H5Gcreate(fid2, "/W", (size_t)0)) < 0) TEST_ERROR
+    if(H5Gclose(gid2) < 0) TEST_ERROR
+    if((gid2 = H5Gcreate(fid2, "/W/X", (size_t)0)) < 0) TEST_ERROR
+    if(H5Lcreate_external(filename1, "/A/B/C", gid2, "DLINK", H5P_DEFAULT, H5P_DEFAULT) < 0) TEST_ERROR
+    if(H5Gclose(gid2) < 0) TEST_ERROR
+    if(H5Fclose(fid2) < 0) TEST_ERROR
+
+    /* Access external link from file #1 */
+    if((fid2 = H5Fopen(filename2, H5F_ACC_RDONLY, fapl)) < 0) TEST_ERROR
+    if((gid2 = H5Gopen(fid2, "/W/X/DLINK")) < 0) TEST_ERROR
+    if((name_len = H5Iget_name(gid2, objname, (size_t)NAME_BUF_SIZE )) < 0) TEST_ERROR
+    if(HDstrcmp(objname, "/A/B/C")) TEST_ERROR
+    if(H5Gclose(gid2) < 0) TEST_ERROR
+    if(H5Fclose(fid2) < 0) TEST_ERROR
+
+
+    PASSED();
+    return 0;
+
+error:
+    H5E_BEGIN_TRY {
+        H5Gclose(fapl);
+        H5Gclose(gid2);
+        H5Gclose(gid1);
+        H5Fclose(fid2);
+        H5Fclose(fid1);
+    } H5E_END_TRY;
+    return -1;
+} /* end external_link_strong() */
+
 
 /*-------------------------------------------------------------------------
  * Function:    ud_hard_links
@@ -9552,6 +9636,7 @@ main(void)
             nerrors += external_link_closing((new_format ? fapl2 : fapl), new_format) < 0 ? 1 : 0;
 #endif /* H5_CANNOT_OPEN_TWICE */
             nerrors += external_link_endian((new_format ? fapl2 : fapl), new_format) < 0 ? 1 : 0;
+            nerrors += external_link_strong((new_format ? fapl2 : fapl), new_format) < 0 ? 1 : 0;
 
             /* These tests assume that external links are a form of UD links,
              * so assume that everything that passed for external links