[svn-r11215] Purpose:

    Bug fix & code cleanup

Description:
    Fix another bug in the file mounting code and refactor the unmount
code that it is simpler.

Platforms tested:
    FreeBSD 4.11 (sleipnir)
    Linux 2.4
    Too minor to require h5committest

7 files changed, 327 insertions, 252 deletions

diff --git a/src/H5F.c b/src/H5F.c
index ea9e608..4cd5b67 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -60,12 +60,6 @@ typedef struct H5F_olist_t {
     int   max_index;            /* Maximum # of IDs to put into array */
 } H5F_olist_t;    
 
-/* Struct for tracking "shared" file structs */
-typedef struct H5F_sfile_node_t {
-    H5F_file_t *shared;         /* Pointer to "shared" struct */
-    struct H5F_sfile_node_t *next;   /* Pointer to next node */
-} H5F_sfile_node_t;
-
 /* PRIVATE PROTOTYPES */
 
 #ifdef NOT_YET
@@ -81,23 +75,12 @@ static unsigned H5F_get_objects(const H5F_t *f, unsigned types, int max_objs, hi
 static int H5F_get_objects_cb(void *obj_ptr, hid_t obj_id, void *key);
 static herr_t H5F_get_vfd_handle(const H5F_t *file, hid_t fapl, void** file_handle);
 
-/* Routines to operate on the shared file list */
-static herr_t H5F_shared_add(H5F_file_t *shared);
-static H5F_file_t * H5F_shared_search(H5FD_t *lf);
-static herr_t H5F_shared_remove(H5F_file_t *shared);
-
 /* Declare a free list to manage the H5F_t struct */
 H5FL_DEFINE_STATIC(H5F_t);
 
 /* Declare a free list to manage the H5F_file_t struct */
 H5FL_DEFINE_STATIC(H5F_file_t);
 
-/* Declare a free list to manage the H5F_sfile_node_t struct */
-H5FL_DEFINE_STATIC(H5F_sfile_node_t);
-
-/* Declare a local variable to track the shared file information */
-H5F_sfile_node_t *H5F_sfile_head_g = NULL;
-
 
 /*-------------------------------------------------------------------------
  * Function:	H5F_init
@@ -452,7 +435,7 @@ H5F_term_interface(void)
             H5I_clear_type(H5I_FILE, FALSE);
 	} else {
             /* Make certain we've cleaned up all the shared file objects */
-            HDassert(H5F_sfile_head_g == NULL);
+            H5F_sfile_assert_num(0);
 
 	    H5I_dec_type_ref(H5I_FILE);
 	    H5_interface_initialize_g = 0;
@@ -1535,7 +1518,7 @@ H5F_new(H5F_file_t *shared, hid_t fcpl_id, hid_t fapl_id)
 	    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to create open object data structure")
 
         /* Add new "shared" struct to list of open files */
-        if(H5F_shared_add(f->shared) < 0)
+        if(H5F_sfile_add(f->shared) < 0)
 	    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to append to list of open files")
     } /* end else */
     
@@ -1601,7 +1584,7 @@ H5F_dest(H5F_t *f, hid_t dxpl_id)
 
     if (1==f->shared->nrefs) {
         /* Remove shared file struct from list of open files */
-        if(H5F_shared_remove(f->shared) < 0) {
+        if(H5F_sfile_remove(f->shared) < 0) {
             HERROR(H5E_FILE, H5E_CANTRELEASE, "problems closing file");
             ret_value = FAIL; /*but keep going*/
         } /* end if */
@@ -1811,7 +1794,7 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, hid_t d
     } /* end if */
 
     /* Is the file already open? */
-    if ((shared = H5F_shared_search(lf)) != NULL) {
+    if ((shared = H5F_sfile_search(lf)) != NULL) {
 	/*
 	 * The file is already open, so use that one instead of the one we
 	 * just opened. We only one one H5FD_t* per file so one doesn't
@@ -2579,6 +2562,24 @@ H5F_close(H5F_t *f)
     HDassert(f);
     HDassert(f->file_id > 0);   /* This routine should only be called when a file ID's ref count drops to zero */
 
+    /* Perform checks for "semi" file close degree here, since closing the
+     * file is not allowed if there are objects still open */
+    if(f->shared->fc_degree == H5F_CLOSE_SEMI) {
+        unsigned nopen_files = 0;       /* Number of open files in file/mount hierarchy */
+        unsigned nopen_objs = 0;        /* Number of open objects in file/mount hierarchy */
+
+        /* Get the number of open objects and open files on this file/mount hierarchy */
+        if(H5F_mount_count_ids(f, &nopen_files, &nopen_objs) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_MOUNT, FAIL, "problem checking mount hierarchy")
+
+        /* If there are no other file IDs open on this file/mount hier., but
+         * there are still open objects, issue an error and bail out now,
+         * without decrementing the file ID's reference count and triggering
+         * a "real" attempt at closing the file */
+        if(nopen_files == 1 && nopen_objs > 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close file, there are objects still open")
+    } /* end if */
+
     /* Reset the file ID for this file */
     f->file_id = -1;
 
@@ -2781,43 +2782,15 @@ done:
 herr_t
 H5Fclose(hid_t file_id)
 {
-    H5F_t	*f;
     herr_t	ret_value = SUCCEED;
 
     FUNC_ENTER_API(H5Fclose, FAIL)
     H5TRACE1("e","i",file_id);
 
     /* Check/fix arguments. */
-    if (NULL == (f = H5I_object_verify(file_id,H5I_FILE)))
+    if (H5I_FILE != H5I_get_type(file_id))
 	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file ID")
 
-    /* Perform checks for "semi" file close degree here, since closing the
-     * file ID will mess things up if we need to return FAIL */
-    if(f->shared->fc_degree == H5F_CLOSE_SEMI) {
-        int ref_count;                  /* Reference count for file's ID */
-
-        /* Get the reference count for this ID */
-        if((ref_count = H5I_get_ref(file_id)) < 0)
-            HGOTO_ERROR (H5E_ATOM, H5E_CANTGET, FAIL, "can't get ID ref count")
-
-        /* If we will be decrementing the reference count to zero, check for objects open */
-        if(ref_count == 1) {
-            unsigned nopen_files = 0;       /* Number of open files in file/mount hierarchy */
-            unsigned nopen_objs = 0;        /* Number of open objects in file/mount hierarchy */
-
-            /* Get the number of open objects and open files on this file/mount hierarchy */
-            if(H5F_mount_count_ids(f, &nopen_files, &nopen_objs) < 0)
-                HGOTO_ERROR(H5E_SYM, H5E_MOUNT, FAIL, "problem checking mount hierarchy")
-
-            /* If there are no other file IDs open on this file/mount hier., but
-             * there are still open objects, issue an error and bail out now,
-             * before decrementing the file ID's reference count and triggering
-             * a "real" attempt at closing the file */
-            if(nopen_files == 1 && nopen_objs > 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "can't close file, there are objects still open")
-        } /* end if */
-    } /* end if */
-
     /*
      * Decrement reference count on atom.  When it reaches zero the file will
      * be closed.
@@ -4163,142 +4136,3 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Fget_name() */
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5F_shared_add
- *
- * Purpose:	Add a "shared" file struct to the list of open files
- *
- * Return:	SUCCEED/FAIL
- *
- * Programmer:	Quincey Koziol
- *              Monday, July 18, 2005
- *
- * Modifications:
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5F_shared_add(H5F_file_t *shared)
-{
-    H5F_sfile_node_t *new_shared;              /* New shared file node */
-    herr_t ret_value = SUCCEED;         /* Return value */
-    
-    FUNC_ENTER_NOAPI_NOINIT(H5F_shared_add)
-
-    /* Sanity check */
-    HDassert(shared);
-
-    /* Allocate new shared file node */
-    if (NULL == (new_shared = H5FL_CALLOC(H5F_sfile_node_t)))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
-
-    /* Set shared file value */
-    new_shared->shared = shared;
-
-    /* Prepend to list of shared files open */
-    new_shared->next = H5F_sfile_head_g;
-    H5F_sfile_head_g = new_shared;
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_shared_add() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5F_shared_search
- *
- * Purpose:	Search for a "shared" file with low-level file info that
- *              matches
- *
- * Return:	Non-NULL on success / NULL on failure
- *
- * Programmer:	Quincey Koziol
- *              Monday, July 18, 2005
- *
- * Modifications:
- *
- *-------------------------------------------------------------------------
- */
-static H5F_file_t *
-H5F_shared_search(H5FD_t *lf)
-{
-    H5F_sfile_node_t *curr;             /* Current shared file node */
-    H5F_file_t *ret_value = NULL;       /* Return value */
-    
-    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_shared_search)
-
-    /* Sanity check */
-    HDassert(lf);
-
-    /* Iterate through low-level files for matching low-level file info */
-    curr = H5F_sfile_head_g;
-    while(curr) {
-        /* Check for match */
-        if(0==H5FD_cmp(curr->shared->lf, lf))
-            HGOTO_DONE(curr->shared)
-
-        /* Advance to next shared file node */
-        curr = curr->next;
-    } /* end while */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_shared_search() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5F_shared_remove
- *
- * Purpose:	Remove a "shared" file struct from the list of open files
- *
- * Return:	SUCCEED/FAIL
- *
- * Programmer:	Quincey Koziol
- *              Monday, July 18, 2005
- *
- * Modifications:
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5F_shared_remove(H5F_file_t *shared)
-{
-    H5F_sfile_node_t *curr;             /* Current shared file node */
-    H5F_sfile_node_t *last;             /* Last shared file node */
-    herr_t ret_value = SUCCEED;         /* Return value */
-    
-    FUNC_ENTER_NOAPI_NOINIT(H5F_shared_remove)
-
-    /* Sanity check */
-    HDassert(shared);
-
-    /* Locate shared file node with correct shared file */
-    last = NULL;
-    curr = H5F_sfile_head_g;
-    while(curr && curr->shared != shared) {
-        /* Advance to next node */
-        last = curr;
-        curr = curr->next;
-    } /* end while */
-
-    /* Indicate error if the node wasn't found */
-    if(curr == NULL)
-	HGOTO_ERROR(H5E_FILE, H5E_NOTFOUND, FAIL, "can't find shared file info")
-
-    /* Remove node found from list */
-    if(last != NULL)
-        /* Removing middle or tail node in list */
-        last->next = curr->next;
-    else
-        /* Removing head node in list */
-        H5F_sfile_head_g = curr->next;
-
-    /* Release the shared file node struct */
-    /* (the shared file info itself is freed elsewhere) */
-    H5FL_FREE(H5F_sfile_node_t, curr);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_shared_remove() */
-
diff --git a/src/H5Fmount.c b/src/H5Fmount.c
index 7e234a5..18feb9c 100644
--- a/src/H5Fmount.c
+++ b/src/H5Fmount.c
@@ -34,7 +34,7 @@
 NAME
    H5F_init_mount_interface -- Initialize interface-specific information
 USAGE
-    herr_t H5T_init_mount_interface()
+    herr_t H5F_init_mount_interface()
    
 RETURNS
     Non-negative on success/Negative on failure
@@ -256,15 +256,15 @@ static herr_t
 H5F_unmount(H5G_entry_t *loc, const char *name, hid_t dxpl_id)
 {
     H5G_t	*mounted = NULL;	/*mount point group		*/
+    H5G_t	*child_group = NULL;	/* Child's group in parent mtab	*/
+    H5F_t	*child_file = NULL;	/* Child's file in parent mtab	*/
     H5G_entry_t	*mnt_ent = NULL;	/*mounted symbol table entry	*/
     H5F_t	*child = NULL;		/*mounted file			*/
     H5F_t	*parent = NULL;		/*file where mounted		*/
     H5G_entry_t	*ent = NULL;		/*temporary symbol table entry	*/
-    H5G_entry_t mnt_open_ent;       /* entry used to open mount point*/
-    herr_t	ret_value = FAIL;	/*return value			*/
-    unsigned	i;			/*coutners			*/
-    unsigned	lt, rt, md=0;	        /*binary search indices		*/
-    int 	cmp;		        /*binary search comparison value*/
+    H5G_entry_t mnt_open_ent;           /* entry used to open mount point*/
+    int         child_idx;              /* Index of child in parent's mtab */
+    herr_t	ret_value = SUCCEED;	/*return value			*/
     
     FUNC_ENTER_NOAPI_NOINIT(H5F_unmount)
 
@@ -283,37 +283,27 @@ H5F_unmount(H5G_entry_t *loc, const char *name, hid_t dxpl_id)
     child = H5G_fileof(mounted);
     mnt_ent = H5G_entof(mounted);
     ent = H5G_entof(child->shared->root_grp);
+    child_idx = -1;
 
     if (child->mtab.parent && H5F_addr_eq(mnt_ent->header, ent->header)) {
+        unsigned	u;		/*counters			*/
+
 	/*
 	 * We've been given the root group of the child.  We do a reverse
 	 * lookup in the parent's mount table to find the correct entry.
 	 */
 	parent = child->mtab.parent;
-	for (i=0; i<parent->mtab.nmounts; i++) {
-	    if (parent->mtab.child[i].file==child) {
-                /* Search the open IDs replace names to reflect unmount operation */
-                if (H5G_replace_name( H5G_UNKNOWN, mnt_ent, mnt_ent->user_path_r, NULL, NULL, NULL, OP_UNMOUNT )<0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to replace name ")
-
-		/* Unmount the child */
-		parent->mtab.nmounts -= 1;
-                if(H5G_unmount(parent->mtab.child[md].group)<0)
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to reset group mounted flag")
-		if(H5G_close(parent->mtab.child[i].group)<0)
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close unmounted group")
-		child->mtab.parent = NULL;
-		if(H5F_try_close(child)<0)
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "unable to close unmounted file")
-
-                /* Eliminate the mount point from the table */
-		HDmemmove(parent->mtab.child+i, parent->mtab.child+i+1,
-                    (parent->mtab.nmounts-i)* sizeof(parent->mtab.child[0]));
-		ret_value = SUCCEED;
+	for (u=0; u<parent->mtab.nmounts; u++) {
+	    if (parent->mtab.child[u].file==child) {
+                /* Found the correct index */
+                child_idx = u;
+                break;
 	    }
 	}
-	HDassert(ret_value>=0);
     } else {
+        unsigned lt, rt, md=0;	        /*binary search indices		*/
+        int 	cmp;		        /*binary search comparison value*/
+
 	/*
 	 * We've been given the mount point in the parent.  We use a binary
 	 * search in the parent to locate the mounted file, if any.
@@ -335,22 +325,37 @@ H5F_unmount(H5G_entry_t *loc, const char *name, hid_t dxpl_id)
 	if (cmp)
 	    HGOTO_ERROR(H5E_FILE, H5E_MOUNT, FAIL, "not a mount point")
 
-	/* Unmount the child */
-	parent->mtab.nmounts -= 1;
-	if(H5G_unmount(parent->mtab.child[md].group)<0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to reset group mounted flag")
-	if(H5G_close(parent->mtab.child[md].group)<0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close unmounted group")
-	parent->mtab.child[md].file->mtab.parent = NULL;
-	if(H5F_try_close(parent->mtab.child[md].file)<0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "unable to close unmounted file")
-
-        /* Eliminate the mount point from the table */
-	HDmemmove(parent->mtab.child+md, parent->mtab.child+md+1,
-            (parent->mtab.nmounts-md)*sizeof(parent->mtab.child[0]));
-	ret_value = SUCCEED;
+        /* Found the correct index */
+        child_idx = md;
+        mnt_ent = ent;
     }
-    
+
+    HDassert(child_idx >= 0);
+
+    /* Search the open IDs replace names to reflect unmount operation */
+    if (H5G_replace_name(H5G_UNKNOWN, mnt_ent, mnt_ent->user_path_r, NULL, NULL, NULL, OP_UNMOUNT )<0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to replace name ")
+
+    /* Save the information about the child from the mount table */
+    child_group = parent->mtab.child[child_idx].group;
+    child_file = parent->mtab.child[child_idx].file;
+
+    /* Eliminate the mount point from the table */
+    HDmemmove(parent->mtab.child+child_idx, parent->mtab.child+child_idx+1,
+        (parent->mtab.nmounts-child_idx)*sizeof(parent->mtab.child[0]));
+    parent->mtab.nmounts -= 1;
+
+    /* Unmount the child file from the parent file */
+    if(H5G_unmount(child_group)<0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to reset group mounted flag")
+    if(H5G_close(child_group)<0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close unmounted group")
+
+    /* Detach child file from parent & see if it should close */
+    child_file->mtab.parent = NULL;
+    if(H5F_try_close(child_file)<0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "unable to close unmounted file")
+
 done:
     if (mounted)
         if(H5G_close(mounted)<0 && ret_value>=0)
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index 596103e..8e68d0b 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -178,5 +178,10 @@ H5_DLL hsize_t H5F_init_superblock(const H5F_t *f, hid_t dxpl_id);
 H5_DLL herr_t H5F_write_superblock(H5F_t *f, hid_t dxpl_id, uint8_t *buf);
 H5_DLL herr_t H5F_read_superblock(H5F_t *f, hid_t dxpl_id, H5G_entry_t *root_ent, haddr_t addr, uint8_t *buf, size_t buf_size);
 
+/* Shared file list related routines */
+H5_DLL herr_t H5F_sfile_add(H5F_file_t *shared);
+H5_DLL H5F_file_t * H5F_sfile_search(H5FD_t *lf);
+H5_DLL herr_t H5F_sfile_remove(H5F_file_t *shared);
+
 #endif
 
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 52b92dc..697a260 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -481,6 +481,9 @@ H5_DLL herr_t H5F_acs_close(hid_t fapl_id, void *close_data);
 H5_DLL herr_t H5F_acs_copy(hid_t new_fapl_id, hid_t old_fapl_id, 
                             void *close_data);
 
+/* Shared file list related routines */
+H5_DLL herr_t H5F_sfile_assert_num(unsigned n);
+
 /* Debugging functions */
 H5_DLL herr_t H5F_debug(H5F_t *f, hid_t dxpl_id, FILE * stream, int indent, int fwidth);
 
diff --git a/src/H5Fsfile.c b/src/H5Fsfile.c
new file mode 100644
index 0000000..70eb420
--- /dev/null
+++ b/src/H5Fsfile.c
@@ -0,0 +1,226 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdf.ncsa.uiuc.edu/HDF5/doc/Copyright.html.  If you do not have     *
+ * access to either file, you may request a copy from hdfhelp@ncsa.uiuc.edu. *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+#define H5F_PACKAGE		/*suppress error about including H5Fpkg	  */
+
+/* Packages needed by this file... */
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Fpkg.h"             /* File access				*/
+#include "H5FDprivate.h"	/* File drivers				*/
+#include "H5FLprivate.h"	/* Free lists                           */
+
+/* PRIVATE TYPEDEFS */
+
+/* Struct for tracking "shared" file structs */
+typedef struct H5F_sfile_node_t {
+    H5F_file_t *shared;                 /* Pointer to "shared" file struct */
+    struct H5F_sfile_node_t *next;      /* Pointer to next node */
+} H5F_sfile_node_t;
+
+/* PRIVATE PROTOTYPES */
+
+/* PRIVATE VARIABLES */
+
+/* Declare a free list to manage the H5F_sfile_node_t struct */
+H5FL_DEFINE_STATIC(H5F_sfile_node_t);
+
+/* Declare a local variable to track the shared file information */
+H5F_sfile_node_t *H5F_sfile_head_g = NULL;
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_sfile_assert_empty
+ *
+ * Purpose:	Sanity checking that shared file list is empty
+ *
+ * Return:	SUCCEED/FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, July 25, 2005
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_sfile_assert_num(unsigned n)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_sfile_assert_num)
+
+    if(n == 0) {
+        /* Sanity checking */
+        HDassert(H5F_sfile_head_g == NULL);
+    } /* end if */
+    else {
+        unsigned count;                 /* Number of open shared files */
+        H5F_sfile_node_t *curr;         /* Current shared file node */
+
+        /* Iterate through low-level files for matching low-level file info */
+        curr = H5F_sfile_head_g;
+        count = 0;
+        while(curr) {
+            /* Increment # of open shared file structs */
+            count++;
+
+            /* Advance to next shared file node */
+            curr = curr->next;
+        } /* end while */
+
+        /* Sanity checking */
+        HDassert(count == n);
+    } /* end else */
+
+    FUNC_LEAVE_NOAPI(SUCCEED);
+} /* H5F_sfile_assert_num() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_sfile_add
+ *
+ * Purpose:	Add a "shared" file struct to the list of open files
+ *
+ * Return:	SUCCEED/FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, July 18, 2005
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_sfile_add(H5F_file_t *shared)
+{
+    H5F_sfile_node_t *new_shared;              /* New shared file node */
+    herr_t ret_value = SUCCEED;         /* Return value */
+    
+    FUNC_ENTER_NOAPI_NOINIT(H5F_sfile_add)
+
+    /* Sanity check */
+    HDassert(shared);
+
+    /* Allocate new shared file node */
+    if (NULL == (new_shared = H5FL_CALLOC(H5F_sfile_node_t)))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+    /* Set shared file value */
+    new_shared->shared = shared;
+
+    /* Prepend to list of shared files open */
+    new_shared->next = H5F_sfile_head_g;
+    H5F_sfile_head_g = new_shared;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_sfile_add() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_sfile_search
+ *
+ * Purpose:	Search for a "shared" file with low-level file info that
+ *              matches
+ *
+ * Return:	Non-NULL on success / NULL on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, July 18, 2005
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+H5F_file_t *
+H5F_sfile_search(H5FD_t *lf)
+{
+    H5F_sfile_node_t *curr;             /* Current shared file node */
+    H5F_file_t *ret_value = NULL;       /* Return value */
+    
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5F_sfile_search)
+
+    /* Sanity check */
+    HDassert(lf);
+
+    /* Iterate through low-level files for matching low-level file info */
+    curr = H5F_sfile_head_g;
+    while(curr) {
+        /* Check for match */
+        if(0==H5FD_cmp(curr->shared->lf, lf))
+            HGOTO_DONE(curr->shared)
+
+        /* Advance to next shared file node */
+        curr = curr->next;
+    } /* end while */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_sfile_search() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_sfile_remove
+ *
+ * Purpose:	Remove a "shared" file struct from the list of open files
+ *
+ * Return:	SUCCEED/FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, July 18, 2005
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_sfile_remove(H5F_file_t *shared)
+{
+    H5F_sfile_node_t *curr;             /* Current shared file node */
+    H5F_sfile_node_t *last;             /* Last shared file node */
+    herr_t ret_value = SUCCEED;         /* Return value */
+    
+    FUNC_ENTER_NOAPI_NOINIT(H5F_sfile_remove)
+
+    /* Sanity check */
+    HDassert(shared);
+
+    /* Locate shared file node with correct shared file */
+    last = NULL;
+    curr = H5F_sfile_head_g;
+    while(curr && curr->shared != shared) {
+        /* Advance to next node */
+        last = curr;
+        curr = curr->next;
+    } /* end while */
+
+    /* Indicate error if the node wasn't found */
+    if(curr == NULL)
+	HGOTO_ERROR(H5E_FILE, H5E_NOTFOUND, FAIL, "can't find shared file info")
+
+    /* Remove node found from list */
+    if(last != NULL)
+        /* Removing middle or tail node in list */
+        last->next = curr->next;
+    else
+        /* Removing head node in list */
+        H5F_sfile_head_g = curr->next;
+
+    /* Release the shared file node struct */
+    /* (the shared file info itself is freed elsewhere) */
+    H5FL_FREE(H5F_sfile_node_t, curr);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_sfile_remove() */
+
diff --git a/src/Makefile.am b/src/Makefile.am
index 0644418..7091120 100755
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -48,7 +48,7 @@ libhdf5_la_SOURCES= H5.c H5A.c H5AC.c H5B.c H5B2.c H5B2cache.c H5B2dbg.c      \
         H5Dcontig.c \
         H5Dcompact.c \
         H5Defl.c H5Dio.c H5Distore.c H5Dmpio.c H5Dselect.c H5Dtest.c H5E.c H5F.c \
-        H5Fdbg.c H5Fmount.c H5Fsuper.c H5FD.c H5FDcore.c  \
+        H5Fdbg.c H5Fmount.c H5Fsfile.c H5Fsuper.c H5FD.c H5FDcore.c  \
         H5FDfamily.c H5FDfphdf5.c H5FDlog.c H5FDmpi.c H5FDmpio.c   \
         H5FDmpiposix.c H5FDmulti.c H5FDsec2.c H5FDstdio.c           \
         H5FDstream.c H5FL.c H5FO.c H5FP.c H5FPclient.c H5FPserver.c H5FS.c    \
diff --git a/src/Makefile.in b/src/Makefile.in
index c92dabe..109c53f 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -88,25 +88,26 @@ am_libhdf5_la_OBJECTS = H5.lo H5A.lo H5AC.lo H5B.lo H5B2.lo \
 	H5BTdbg.lo H5BTtest.lo H5C.lo H5D.lo H5Dcontig.lo \
 	H5Dcompact.lo H5Defl.lo H5Dio.lo H5Distore.lo H5Dmpio.lo \
 	H5Dselect.lo H5Dtest.lo H5E.lo H5F.lo H5Fdbg.lo H5Fmount.lo \
-	H5Fsuper.lo H5FD.lo H5FDcore.lo H5FDfamily.lo H5FDfphdf5.lo \
-	H5FDlog.lo H5FDmpi.lo H5FDmpio.lo H5FDmpiposix.lo H5FDmulti.lo \
-	H5FDsec2.lo H5FDstdio.lo H5FDstream.lo H5FL.lo H5FO.lo H5FP.lo \
-	H5FPclient.lo H5FPserver.lo H5FS.lo H5G.lo H5Gent.lo \
-	H5Gnode.lo H5Gstab.lo H5HG.lo H5HGdbg.lo H5HL.lo H5HLdbg.lo \
-	H5HP.lo H5I.lo H5MF.lo H5MM.lo H5MP.lo H5MPtest.lo H5O.lo \
-	H5Oattr.lo H5Obogus.lo H5Ocont.lo H5Odtype.lo H5Oefl.lo \
-	H5Ofill.lo H5Olayout.lo H5Omtime.lo H5Oname.lo H5Onull.lo \
-	H5Opline.lo H5Osdspace.lo H5Oshared.lo H5Ostab.lo H5P.lo \
-	H5Pdcpl.lo H5Pdxpl.lo H5Pfapl.lo H5Pfcpl.lo H5Pocpl.lo \
-	H5Ptest.lo H5R.lo H5RC.lo H5RS.lo H5S.lo H5Sall.lo H5Shyper.lo \
-	H5Smpio.lo H5Snone.lo H5Spoint.lo H5Sselect.lo H5Stest.lo \
-	H5SH.lo H5SHcache.lo H5SHdbg.lo H5SL.lo H5ST.lo H5T.lo \
-	H5Tarray.lo H5Tbit.lo H5Tcommit.lo H5Tcompound.lo H5Tconv.lo \
-	H5Tcset.lo H5Tenum.lo H5Tfields.lo H5Tfixed.lo H5Tfloat.lo \
-	H5Tinit.lo H5Tnative.lo H5Toffset.lo H5Topaque.lo H5Torder.lo \
-	H5Tpad.lo H5Tprecis.lo H5Tstrpad.lo H5Tvlen.lo H5TS.lo H5V.lo \
-	H5Z.lo H5Zdeflate.lo H5Zfletcher32.lo H5Znbit.lo H5Zshuffle.lo \
-	H5Zszip.lo H5Zscaleoffset.lo H5Ztrans.lo
+	H5Fsfile.lo H5Fsuper.lo H5FD.lo H5FDcore.lo H5FDfamily.lo \
+	H5FDfphdf5.lo H5FDlog.lo H5FDmpi.lo H5FDmpio.lo \
+	H5FDmpiposix.lo H5FDmulti.lo H5FDsec2.lo H5FDstdio.lo \
+	H5FDstream.lo H5FL.lo H5FO.lo H5FP.lo H5FPclient.lo \
+	H5FPserver.lo H5FS.lo H5G.lo H5Gent.lo H5Gnode.lo H5Gstab.lo \
+	H5HG.lo H5HGdbg.lo H5HL.lo H5HLdbg.lo H5HP.lo H5I.lo H5MF.lo \
+	H5MM.lo H5MP.lo H5MPtest.lo H5O.lo H5Oattr.lo H5Obogus.lo \
+	H5Ocont.lo H5Odtype.lo H5Oefl.lo H5Ofill.lo H5Olayout.lo \
+	H5Omtime.lo H5Oname.lo H5Onull.lo H5Opline.lo H5Osdspace.lo \
+	H5Oshared.lo H5Ostab.lo H5P.lo H5Pdcpl.lo H5Pdxpl.lo \
+	H5Pfapl.lo H5Pfcpl.lo H5Pocpl.lo H5Ptest.lo H5R.lo H5RC.lo \
+	H5RS.lo H5S.lo H5Sall.lo H5Shyper.lo H5Smpio.lo H5Snone.lo \
+	H5Spoint.lo H5Sselect.lo H5Stest.lo H5SH.lo H5SHcache.lo \
+	H5SHdbg.lo H5SL.lo H5ST.lo H5T.lo H5Tarray.lo H5Tbit.lo \
+	H5Tcommit.lo H5Tcompound.lo H5Tconv.lo H5Tcset.lo H5Tenum.lo \
+	H5Tfields.lo H5Tfixed.lo H5Tfloat.lo H5Tinit.lo H5Tnative.lo \
+	H5Toffset.lo H5Topaque.lo H5Torder.lo H5Tpad.lo H5Tprecis.lo \
+	H5Tstrpad.lo H5Tvlen.lo H5TS.lo H5V.lo H5Z.lo H5Zdeflate.lo \
+	H5Zfletcher32.lo H5Znbit.lo H5Zshuffle.lo H5Zszip.lo \
+	H5Zscaleoffset.lo H5Ztrans.lo
 libhdf5_la_OBJECTS = $(am_libhdf5_la_OBJECTS)
 PROGRAMS = $(noinst_PROGRAMS)
 H5detect_SOURCES = H5detect.c
@@ -380,7 +381,7 @@ libhdf5_la_SOURCES = H5.c H5A.c H5AC.c H5B.c H5B2.c H5B2cache.c H5B2dbg.c      \
         H5Dcontig.c \
         H5Dcompact.c \
         H5Defl.c H5Dio.c H5Distore.c H5Dmpio.c H5Dselect.c H5Dtest.c H5E.c H5F.c \
-        H5Fdbg.c H5Fmount.c H5Fsuper.c H5FD.c H5FDcore.c  \
+        H5Fdbg.c H5Fmount.c H5Fsfile.c H5Fsuper.c H5FD.c H5FDcore.c  \
         H5FDfamily.c H5FDfphdf5.c H5FDlog.c H5FDmpi.c H5FDmpio.c   \
         H5FDmpiposix.c H5FDmulti.c H5FDsec2.c H5FDstdio.c           \
         H5FDstream.c H5FL.c H5FO.c H5FP.c H5FPclient.c H5FPserver.c H5FS.c    \
@@ -583,6 +584,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5FS.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Fdbg.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Fmount.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Fsfile.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Fsuper.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5G.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Gent.Plo@am__quote@