[svn-r22254] Description:

	Bring r22085:22251 from trunk to revise_chunks branch.

	Also tackle some testing issues in test/objcopy.c test and clean up
some warnings.

Tested on:
        FreeBSD/32 8.2 (loyalty) w/gcc4.6, w/C++ & FORTRAN, in debug mode
        FreeBSD/64 8.2 (freedom) w/gcc4.6, w/C++ & FORTRAN, in debug mode
        Linux/32 2.6 (jam) w/PGI compilers, w/default API=1.8.x,
                w/C++ & FORTRAN, w/threadsafe, in debug mode
        Linux/64-amd64 2.6 (koala) w/Intel compilers, w/default API=1.6.x,
                w/C++ & FORTRAN, in production mode
        Solaris/32 2.10 (linew) w/deprecated symbols disabled, w/C++ & FORTRAN,
                w/szip filter, w/threadsafe, in production mode
        Linux/PPC 2.6 (ostrich) w/C++ & FORTRAN, w/threadsafe, in debug mode
        Linux/64-ia64 2.6 (ember) w/Intel compilers, w/paralle, C++ & FORTRAN,
                in production mode
        Mac OS X/32 10.7.3 (amazon) in debug mode
        Mac OS X/32 10.7.3 (amazon) w/C++ & FORTRAN, w/threadsafe,
                in production mode
        Mac OS X/32 10.7.3 (amazon) w/parallel, in debug mode

1 files changed, 292 insertions, 144 deletions

diff --git a/src/H5FDcore.c b/src/H5FDcore.c
index 7fa0e7c..cc48e51 100644
--- a/src/H5FDcore.c
+++ b/src/H5FDcore.c
@@ -38,8 +38,24 @@
 /* The driver identification number, initialized at runtime */
 static hid_t H5FD_CORE_g = 0;
 
-/*
- * The description of a file belonging to this driver. The `eoa' and `eof'
+/* Since Windows doesn't follow the rest of the world when it comes
+ * to POSIX I/O types, some typedefs and constants are needed to avoid
+ * making the code messy with #ifdefs.
+ * NOTE: These are only used when writing data to the backing store on
+ * file close.
+ */
+#ifdef H5_HAVE_WIN32_API
+typedef unsigned int    h5_core_io_t;
+typedef int             h5_core_io_ret_t;
+static int H5_CORE_MAX_IO_BYTES_g = INT_MAX;
+#else
+/* Unix, everyone else */
+typedef size_t          h5_core_io_t;
+typedef ssize_t         h5_core_io_ret_t;
+static size_t H5_CORE_MAX_IO_BYTES_g = SSIZET_MAX;
+#endif /* H5_HAVE_WIN32_API */
+
+/* The description of a file belonging to this driver. The `eoa' and `eof'
  * determine the amount of hdf5 address space in use and the high-water mark
  * of the file (the current size of the underlying memory).
  */
@@ -54,8 +70,7 @@ typedef struct H5FD_core_t {
     int		fd;			/*backing store file descriptor	*/
     /* Information for determining uniqueness of a file with a backing store */
 #ifndef H5_HAVE_WIN32_API
-    /*
-     * On most systems the combination of device and i-node number uniquely
+    /* On most systems the combination of device and i-node number uniquely
      * identify a file.
      */
     dev_t       device;                 /*file device number            */
@@ -65,19 +80,28 @@ typedef struct H5FD_core_t {
     ino_t       inode;                  /*file i-node number            */
 #endif /*H5_VMS*/
 #else
-    /*
-     * On H5_HAVE_WIN32_API the low-order word of a unique identifier associated with the
-     * file and the volume serial number uniquely identify a file. This number
-     * (which, both? -rpm) may change when the system is restarted or when the
-     * file is opened. After a process opens a file, the identifier is
-     * constant until the file is closed. An application can use this
-     * identifier and the volume serial number to determine whether two
-     * handles refer to the same file.
+    /* Files in windows are uniquely identified by the volume serial
+     * number and the file index (both low and high parts).
+     *
+     * There are caveats where these numbers can change, especially
+     * on FAT file systems.  On NTFS, however, a file should keep
+     * those numbers the same until renamed or deleted (though you
+     * can use ReplaceFile() on NTFS to keep the numbers the same
+     * while renaming).
+     *
+     * See the MSDN "BY_HANDLE_FILE_INFORMATION Structure" entry for
+     * more information.
+     *
+     * http://msdn.microsoft.com/en-us/library/aa363788(v=VS.85).aspx
      */
-    DWORD fileindexlo;
-    DWORD fileindexhi;
-#endif
+    DWORD           nFileIndexLow;
+    DWORD           nFileIndexHigh;
+    DWORD           dwVolumeSerialNumber;
+    
+    HANDLE          hFile;      /* Native windows file handle */
+#endif /* H5_HAVE_WIN32_API */
     hbool_t	dirty;			/*changes not saved?		*/
+    H5FD_file_image_callbacks_t fi_callbacks; /* file image callbacks */
 
     /* Information from file open flags, for SWMR access */
     hbool_t     swmr_read;      /* Whether the file is open for SWMR read access */
@@ -92,8 +116,7 @@ typedef struct H5FD_core_fapl_t {
 /* Allocate memory in multiples of this size by default */
 #define H5FD_CORE_INCREMENT		8192
 
-/*
- * These macros check for overflow of various quantities.  These macros
+/* These macros check for overflow of various quantities.  These macros
  * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
  *
  * ADDR_OVERFLOW:	Checks whether a file address of type `haddr_t'
@@ -203,8 +226,6 @@ H5FD_core_init_interface(void)
  * Programmer:	Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 hid_t
@@ -261,15 +282,6 @@ H5FD_core_term(void)
  * Programmer:	Robb Matzke
  *		Thursday, February 19, 1998
  *
- * Modifications:
- * 		Robb Matzke, 1999-10-19
- *		Added the BACKING_STORE argument. If set then the entire file
- *		contents are flushed to a file with the same name as this
- *		core file.
- *
- *		Raymond Lu, 2001-10-25
- *		Changed the file access list to the new generic list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -308,14 +320,6 @@ done:
  * Programmer:	Robb Matzke
  *              Tuesday, August 10, 1999
  *
- * Modifications:
- *		Robb Matzke, 1999-10-19
- *		Added the BACKING_STORE argument.
- *
- *		Raymond Lu
- *		2001-10-25
- *		Changed file access list to the new generic property list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -358,8 +362,6 @@ done:
  * Programmer:	Robb Matzke
  *              Friday, August 13, 1999
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 static void *
@@ -399,16 +401,6 @@ done:
  * Programmer:	Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *		Robb Matzke, 1999-10-19
- *		The backing store file is created and opened if specified.
- *
- *              Raymond Lu, 2006-11-30
- *              Enabled the driver to read an existing file depending on
- *              the setting of the backing_store and file open flags.
- *
- *              Allen Byrne, 2008-1-23
- *              changed if of fapl_id to assert
  *-------------------------------------------------------------------------
  */
 static H5FD_t *
@@ -420,11 +412,11 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     H5FD_core_fapl_t	*fa=NULL;
     H5P_genplist_t *plist;      /* Property list pointer */
 #ifdef H5_HAVE_WIN32_API
-    HFILE filehandle;
     struct _BY_HANDLE_FILE_INFORMATION fileinfo;
 #endif
     h5_stat_t		sb;
     int			fd=-1;
+    H5FD_file_image_info_t   file_image_info;
     H5FD_t		*ret_value;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -447,10 +439,32 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     if(H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
     if(H5F_ACC_EXCL & flags) o_flags |= O_EXCL;
 
+    /* Retrieve initial file image info */
+    if(H5P_get(plist, H5F_ACS_FILE_IMAGE_INFO_NAME, &file_image_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get initial file image info")
+
+    /* If the file image exists and this is an open, make sure the file doesn't exist */
+    HDassert(((file_image_info.buffer != NULL) && (file_image_info.size > 0)) ||
+             ((file_image_info.buffer == NULL) && (file_image_info.size == 0)));
+    if((file_image_info.buffer != NULL) && !(H5F_ACC_CREAT & flags)) {
+        if(HDopen(name, o_flags, 0666) >= 0)
+            HGOTO_ERROR(H5E_FILE, H5E_FILEEXISTS, NULL, "file already exists")
+        
+        /* If backing store is requested, create and stat the file
+         * Note: We are forcing the O_CREAT flag here, even though this is 
+         * technically an open.
+         */
+        if(fa->backing_store) {
+            if((fd = HDopen(name, o_flags | O_CREAT, 0666)) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to create file")
+            if(HDfstat(fd, &sb) < 0)
+                HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
+        } /* end if */
+    }  /* end if */
     /* Open backing store, and get stat() from file.  The only case that backing
      * store is off is when  the backing_store flag is off and H5F_ACC_CREAT is
      * on. */
-    if(fa->backing_store || !(H5F_ACC_CREAT & flags)) {
+    else if(fa->backing_store || !(H5F_ACC_CREAT & flags)) {
         if(fa && (fd = HDopen(name, o_flags, 0666)) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file")
         if(HDfstat(fd, &sb) < 0)
@@ -464,8 +478,7 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     if(name && *name)
         file->name = H5MM_xstrdup(name);
 
-    /*
-     * The increment comes from either the file access property list or the
+    /* The increment comes from either the file access property list or the
      * default value. But if the file access property list was zero then use
      * the default value instead.
      */
@@ -474,13 +487,22 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     /* If save data in backing store. */
     file->backing_store = fa->backing_store;
 
+    /* Save file image callbacks */
+    file->fi_callbacks = file_image_info.callbacks;
+
     if(fd >= 0) {
         /* Retrieve information for determining uniqueness of file */
 #ifdef H5_HAVE_WIN32_API
-        filehandle = _get_osfhandle(fd);
-        (void)GetFileInformationByHandle((HANDLE)filehandle, &fileinfo);
-        file->fileindexhi = fileinfo.nFileIndexHigh;
-        file->fileindexlo = fileinfo.nFileIndexLow;
+        file->hFile = (HANDLE)_get_osfhandle(fd);
+        if(INVALID_HANDLE_VALUE == file->hFile)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to get Windows file handle")
+
+        if(!GetFileInformationByHandle((HANDLE)file->hFile, &fileinfo))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to get Windows file information")
+
+        file->nFileIndexHigh = fileinfo.nFileIndexHigh;
+        file->nFileIndexLow = fileinfo.nFileIndexLow;
+        file->dwVolumeSerialNumber = fileinfo.dwVolumeSerialNumber;
 #else /* H5_HAVE_WIN32_API */
         file->device = sb.st_dev;
 #ifdef H5_VMS
@@ -499,20 +521,70 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
         size_t size;
 
         /* Retrieve file size */
-	size = (size_t)sb.st_size;
+        if(file_image_info.buffer && file_image_info.size > 0)
+            size = file_image_info.size;
+        else
+            size = (size_t)sb.st_size;
 
         /* Check if we should allocate the memory buffer and read in existing data */
         if(size) {
-            /* Allocate memory for the file's data */
-            if(NULL == (file->mem = (unsigned char*)H5MM_malloc(size)))
-                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate memory block")
+            /* Allocate memory for the file's data, using the file image callback if available. */
+            if(file->fi_callbacks.image_malloc) {
+                if(NULL == (file->mem = (unsigned char*)file->fi_callbacks.image_malloc(size, H5FD_FILE_IMAGE_OP_FILE_OPEN, file->fi_callbacks.udata)))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "image malloc callback failed")
+            } /* end if */
+            else {
+                if(NULL == (file->mem = (unsigned char*)H5MM_malloc(size)))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "unable to allocate memory block")
+            } /* end else */
 
             /* Set up data structures */
             file->eof = size;
 
-            /* Read in existing data */
-            if(HDread(file->fd, file->mem, size) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to read file")
+            /* If there is an initial file image, copy it, using the callback if possible */
+            if(file_image_info.buffer && file_image_info.size > 0) {
+                if(file->fi_callbacks.image_memcpy) {
+                    if(file->mem != file->fi_callbacks.image_memcpy(file->mem, file_image_info.buffer, size, H5FD_FILE_IMAGE_OP_FILE_OPEN, file->fi_callbacks.udata))
+                        HGOTO_ERROR(H5E_FILE, H5E_CANTCOPY, NULL, "image_memcpy callback failed")
+                } /* end if */
+                else
+                    HDmemcpy(file->mem, file_image_info.buffer, size);
+            } /* end if */
+            /* Read in existing data from the file if there is no image */
+            else {
+                /* Read in existing data, being careful of interrupted system calls,
+                 * partial results, and the end of the file.
+                 */
+                while(size > 0) {
+                    h5_core_io_t        bytes_in        = 0;    /* # of bytes to read       */
+                    h5_core_io_ret_t    bytes_read      = -1;   /* # of bytes actually read */
+                    
+                    /* Trying to read more bytes than the return type can handle is
+                     * undefined behavior in POSIX.
+                     */
+                    if(size > H5_CORE_MAX_IO_BYTES_g)
+                        bytes_in = H5_CORE_MAX_IO_BYTES_g;
+                    else
+                        bytes_in = (h5_core_io_t)size;
+                    
+                    do {
+                        bytes_read = HDread(file->fd, file->mem, bytes_in);
+                    } while(-1 == bytes_read && EINTR == errno);
+                    
+                    if(-1 == bytes_read) { /* error */
+                        int myerrno = errno;
+                        time_t mytime = HDtime(NULL);
+                        HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+
+                        HGOTO_ERROR(H5E_IO, H5E_READERROR, NULL, "file read failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', file->mem = %p, size = %lu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), file->mem, (unsigned long)size, (unsigned long long)myoffset);
+                    } /* end if */
+                    
+                    HDassert(bytes_read >= 0);
+                    HDassert((size_t)bytes_read <= size);
+                    
+                    size -= (size_t)bytes_read;
+                } /* end while */
+            } /* end else */
         } /* end if */
     } /* end if */
 
@@ -559,8 +631,15 @@ H5FD_core_close(H5FD_t *_file)
         HDclose(file->fd);
     if(file->name)
         H5MM_xfree(file->name);
-    if(file->mem)
-        H5MM_xfree(file->mem);
+    if(file->mem) {
+        /* Use image callback if available */
+        if(file->fi_callbacks.image_free) {
+            if(file->fi_callbacks.image_free(file->mem, H5FD_FILE_IMAGE_OP_FILE_CLOSE, file->fi_callbacks.udata) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "image_free callback failed")
+        } /* end if */
+        else
+            H5MM_xfree(file->mem);
+    } /* end if */
     HDmemset(file, 0, sizeof(H5FD_core_t));
     H5MM_xfree(file);
 
@@ -585,13 +664,6 @@ done:
  * Programmer:	Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *              Neil Fortner
- *              Tuesday, March 9, 2010
- *              Modified function to compare low level file information if
- *              a backing store is opened for both files, similar to the
- *              sec2 file driver.
- *
  *-------------------------------------------------------------------------
  */
 static int
@@ -606,11 +678,14 @@ H5FD_core_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
     if(f1->fd >= 0 && f2->fd >= 0) {
         /* Compare low level file information for backing store */
 #ifdef H5_HAVE_WIN32_API
-        if (f1->fileindexhi < f2->fileindexhi) HGOTO_DONE(-1)
-        if (f1->fileindexhi > f2->fileindexhi) HGOTO_DONE(1)
+        if(f1->dwVolumeSerialNumber < f2->dwVolumeSerialNumber) HGOTO_DONE(-1)
+        if(f1->dwVolumeSerialNumber > f2->dwVolumeSerialNumber) HGOTO_DONE(1)
 
-        if (f1->fileindexlo < f2->fileindexlo) HGOTO_DONE(-1)
-        if (f1->fileindexlo > f2->fileindexlo) HGOTO_DONE(1)
+        if(f1->nFileIndexHigh < f2->nFileIndexHigh) HGOTO_DONE(-1)
+        if(f1->nFileIndexHigh > f2->nFileIndexHigh) HGOTO_DONE(1)
+
+        if(f1->nFileIndexLow < f2->nFileIndexLow) HGOTO_DONE(-1)
+        if(f1->nFileIndexLow > f2->nFileIndexLow) HGOTO_DONE(1)
 
 #else
 #ifdef H5_DEV_T_IS_SCALAR
@@ -685,9 +760,11 @@ H5FD_core_query(const H5FD_t * _file, unsigned long *flags /* out */)
         *flags |= H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
         *flags |= H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
         *flags |= H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
+        *flags |= H5FD_FEAT_ALLOW_FILE_IMAGE;   /* OK to use file image feature with this VFD */
+        *flags |= H5FD_FEAT_CAN_USE_FILE_IMAGE_CALLBACKS;       /* OK to use file image callbacks with this VFD */
 
         /* If the backing store is open, a POSIX file handle is available */
-        if(file->fd >= 0 && file->backing_store)
+        if(file && file->fd >= 0 && file->backing_store)
             *flags |= H5FD_FEAT_POSIX_COMPAT_HANDLE; /* VFD handle is POSIX I/O call compatible */
     } /* end if */
 
@@ -709,11 +786,6 @@ H5FD_core_query(const H5FD_t * _file, unsigned long *flags /* out */)
  * Programmer:	Robb Matzke
  *              Monday, August  2, 1999
  *
- * Modifications:
- *              Raymond Lu
- *              21 Dec. 2006
- *              Added the parameter TYPE.  It's only used for MULTI driver.
- *
  *-------------------------------------------------------------------------
  */
 static haddr_t
@@ -741,11 +813,6 @@ H5FD_core_get_eoa(const H5FD_t *_file, H5FD_mem_t UNUSED type)
  * Programmer:	Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *              Raymond Lu
- *              21 Dec. 2006
- *              Added the parameter TYPE.  It's only used for MULTI driver.
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -782,8 +849,6 @@ done:
  * Programmer:	Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 static haddr_t
@@ -807,8 +872,6 @@ H5FD_core_get_eof(const H5FD_t *_file)
  * Programmer:     Raymond Lu
  *                 Sept. 16, 2002
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -874,8 +937,6 @@ done:
  * Programmer:	Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 /* ARGSUSED */
@@ -888,8 +949,8 @@ H5FD_core_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, hadd
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    assert(file && file->pub.cls);
-    assert(buf);
+    HDassert(file && file->pub.cls);
+    HDassert(buf);
 
     /* Check for overflow conditions */
     if (HADDR_UNDEF == addr)
@@ -947,8 +1008,6 @@ done:
  * Programmer:	Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 /* ARGSUSED */
@@ -985,9 +1044,16 @@ H5FD_core_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, had
         if((addr + size) % file->increment)
             new_eof += file->increment;
 
-        /* (Re)allocate memory for the file buffer */
-        if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate memory block of %llu bytes", (unsigned long long)new_eof)
+        /* (Re)allocate memory for the file buffer, using callbacks if available */
+        if(file->fi_callbacks.image_realloc) {
+            if(NULL == (x = (unsigned char *)file->fi_callbacks.image_realloc(file->mem, new_eof, H5FD_FILE_IMAGE_OP_FILE_RESIZE, file->fi_callbacks.udata)))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block of %llu bytes with callback", (unsigned long long)new_eof)
+        } /* end if */
+        else {
+            if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block of %llu bytes", (unsigned long long)new_eof)
+        } /* end else */
+
 #ifdef H5_CLEAR_MEMORY
 HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
 #endif /* H5_CLEAR_MEMORY */
@@ -998,6 +1064,8 @@ HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
 
     /* Write from BUF to memory */
     HDmemcpy(file->mem + addr, buf, size);
+
+    /* Mark memory buffer as modified */
     file->dirty = TRUE;
 
 done:
@@ -1018,10 +1086,6 @@ done:
  * Programmer:	Robb Matzke
  *              Friday, October 15, 1999
  *
- * Modifications:
- *              Raymond Lu, 2006-11-30
- *              Added a condition check for backing store flag, for an
- *              existing file can be opened for read and write now.
  *-------------------------------------------------------------------------
  */
 /* ARGSUSED */
@@ -1040,19 +1104,40 @@ H5FD_core_flush(H5FD_t *_file, hid_t UNUSED dxpl_id, unsigned UNUSED closing)
 
         if (0!=HDlseek(file->fd, (off_t)0, SEEK_SET))
             HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "error seeking in backing store")
+        
+        while (size > 0) {
 
-        while (size) {
-            ssize_t n;
-
-            H5_CHECK_OVERFLOW(size,hsize_t,size_t);
-            n = HDwrite(file->fd, ptr, (size_t)size);
-            if (n<0 && EINTR==errno)
-                continue;
-            if (n<0)
-                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "error writing backing store")
-            ptr += (size_t)n;
-            size -= (size_t)n;
-        }
+            h5_core_io_t        bytes_in        = 0;    /* # of bytes to write  */
+            h5_core_io_ret_t    bytes_wrote     = -1;   /* # of bytes written   */ 
+
+            /* Trying to write more bytes than the return type can handle is
+             * undefined behavior in POSIX.
+             */
+            if(size > H5_CORE_MAX_IO_BYTES_g)
+                bytes_in = H5_CORE_MAX_IO_BYTES_g;
+            else
+                bytes_in = (h5_core_io_t)size;
+
+            do {
+                bytes_wrote = HDwrite(file->fd, ptr, bytes_in);
+            } while(-1 == bytes_wrote && EINTR == errno);
+            
+            if(-1 == bytes_wrote) { /* error */
+                int myerrno = errno;
+                time_t mytime = HDtime(NULL);
+                HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+
+                HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write to backing store failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', ptr = %p, size = %lu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), ptr, (unsigned long)size, (unsigned long long)myoffset);
+            } /* end if */
+            
+            HDassert(bytes_wrote > 0);
+            HDassert((size_t)bytes_wrote <= size);
+
+            size -= (size_t)bytes_wrote;
+            ptr = (unsigned char *)ptr + bytes_wrote;
+            
+        } /* end while */
+        
         file->dirty = FALSE;
     }
 
@@ -1067,6 +1152,28 @@ done:
  * Purpose:	Makes sure that the true file size is the same (or larger)
  *		than the end-of-address.
  *
+ *		Addendum -- 12/2/11
+ *		For file images opened with the core file driver, it is 
+ *		necessary that we avoid reallocating the core file driver's
+ *		buffer uneccessarily.
+ *
+ *		To this end, I have made the following functional changes
+ *		to this function.  
+ *
+ *		If we are closing, and there is no backing store, this 
+ *		function becomes a no-op.
+ *
+ *		If we are closing, and there is backing store, we set the
+ *		eof to equal the eoa, and truncate the backing store to 
+ *		the new eof
+ *
+ *		If we are not closing, we realloc the buffer to size equal 
+ *		to the smallest multiple of the allocation increment that 
+ *		equals or exceeds the eoa and set the eof accordingly.  
+ *		Note that we no longer truncate	the backing store to the 
+ *		new eof if applicable.
+ *							-- JRM
+ *
  * Return:	Success:	Non-negative
  *		Failure:	Negative
  *
@@ -1077,7 +1184,7 @@ done:
  */
 /* ARGSUSED */
 static herr_t
-H5FD_core_truncate(H5FD_t *_file, hid_t UNUSED dxpl_id, hbool_t UNUSED closing)
+H5FD_core_truncate(H5FD_t *_file, hid_t UNUSED dxpl_id, hbool_t closing)
 {
     H5FD_core_t *file = (H5FD_core_t*)_file;
     size_t new_eof;                             /* New size of memory buffer */
@@ -1087,40 +1194,81 @@ H5FD_core_truncate(H5FD_t *_file, hid_t UNUSED dxpl_id, hbool_t UNUSED closing)
 
     HDassert(file);
 
-    /* Determine new size of memory buffer */
-    H5_ASSIGN_OVERFLOW(new_eof, file->increment * (file->eoa / file->increment), hsize_t, size_t);
-    if(file->eoa % file->increment)
-        new_eof += file->increment;
+    /* if we are closing and not using backing store, do nothing */
+    if(!closing || file->backing_store) {
+        if(closing) /* set eof to eoa */
+            new_eof = file->eoa;
+        else { /* set eof to smallest multiple of increment that exceeds eoa */
+            /* Determine new size of memory buffer */
+            H5_ASSIGN_OVERFLOW(new_eof, file->increment * (file->eoa / file->increment), hsize_t, size_t);
+            if(file->eoa % file->increment)
+                new_eof += file->increment;
+        } /* end else */
+
+        /* Extend the file to make sure it's large enough */
+        if(!H5F_addr_eq(file->eof, (haddr_t)new_eof)) {
+            unsigned char *x;       /* Pointer to new buffer for file data */
+
+            /* (Re)allocate memory for the file buffer, using callback if available */
+            if(file->fi_callbacks.image_realloc) {
+                if(NULL == (x = (unsigned char *)file->fi_callbacks.image_realloc(file->mem, new_eof, H5FD_FILE_IMAGE_OP_FILE_RESIZE, file->fi_callbacks.udata)))
+                  HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block with callback")
+            } /* end if */
+            else {
+                if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block")
+            } /* end else */
 
-    /* Extend the file to make sure it's large enough */
-    if(!H5F_addr_eq(file->eof, (haddr_t)new_eof)) {
-        unsigned char *x;       /* Pointer to new buffer for file data */
-
-        /* (Re)allocate memory for the file buffer */
-        if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate memory block")
 #ifdef H5_CLEAR_MEMORY
-if(file->eof < new_eof)
-    HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
+            if(file->eof < new_eof)
+                HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
 #endif /* H5_CLEAR_MEMORY */
-        file->mem = x;
+            file->mem = x;
 
-        /* Update backing store, if using it */
-        if(file->fd >= 0 && file->backing_store) {
+            /* Update backing store, if using it and if closing */
+            if(closing && (file->fd >= 0) && file->backing_store) {
+#ifdef H5_HAVE_WIN32_API
+                LARGE_INTEGER   li;         /* 64-bit (union) integer for SetFilePointer() call */
+                DWORD           dwPtrLow;   /* Low-order pointer bits from SetFilePointer()
+                                             * Only used as an error code here.
+                                             */
+                DWORD           dwError;    /* DWORD error code from GetLastError() */
+                BOOL            bError;     /* Boolean error flag */
+
+                /* Windows uses this odd QuadPart union for 32/64-bit portability */
+                li.QuadPart = (__int64)file->eoa;
+
+                /* Extend the file to make sure it's large enough.
+                 *
+                 * Since INVALID_SET_FILE_POINTER can technically be a valid return value
+                 * from SetFilePointer(), we also need to check GetLastError().
+                 */
+                dwPtrLow = SetFilePointer(file->hFile, li.LowPart, &li.HighPart, FILE_BEGIN);
+                if(INVALID_SET_FILE_POINTER == dwPtrLow) {
+                    dwError = GetLastError();
+                    if(dwError != NO_ERROR )
+                        HGOTO_ERROR(H5E_FILE, H5E_FILEOPEN, FAIL, "unable to set file pointer")
+                }
+
+                bError = SetEndOfFile(file->hFile);
+                if(0 == bError)
+                    HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+#else /* H5_HAVE_WIN32_API */
 #ifdef H5_VMS
-            /* Reset seek offset to the beginning of the file, so that the file isn't
-             * re-extended later.  This may happen on Open VMS. */
-            if(-1 == HDlseek(file->fd, 0, SEEK_SET))
-                HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
-#endif
+                /* Reset seek offset to the beginning of the file, so that the file isn't
+                 * re-extended later.  This may happen on Open VMS. */
+                if(-1 == HDlseek(file->fd, (HDoff_t)0, SEEK_SET))
+                    HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
+#endif /* H5_VMS */
+                if(-1 == HDftruncate(file->fd, (HDoff_t)new_eof))
+                    HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+#endif /* H5_HAVE_WIN32_API */
+            } /* end if */
 
-            if(-1 == HDftruncate(file->fd, (off_t)new_eof))
-                HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+            /* Update the eof value */
+            file->eof = new_eof;
         } /* end if */
-
-        /* Update the eof value */
-        file->eof = new_eof;
-    } /* end if */
+    } /* end if(file->eof < file->eoa) */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)