Index: src/rrd_resize.c
===================================================================
--- src/rrd_resize.c	(revision 1598)
+++ src/rrd_resize.c	(working copy)
@@ -93,7 +93,7 @@
     }
     rrdnew.stat_head->float_cookie = rrd_file->file_len +
         (rrdold.stat_head->ds_cnt * sizeof(rrd_value_t) * modify);
-    rrd_out_file = rrd_open(outfilename, &rrdnew, RRD_READWRITE | RRD_CREAT);
+    rrd_out_file = rrd_open(outfilename, &rrdnew, RRD_READWRITE | RRD_CREAT | RRD_CREAT_SETSIZE);
     if (rrd_out_file == NULL) {
         rrd_set_error("Can't create '%s': %s", outfilename,
                       rrd_strerror(errno));
Index: src/rrd_create.c
===================================================================
--- src/rrd_create.c	(revision 1598)
+++ src/rrd_create.c	(working copy)
@@ -671,36 +671,31 @@
     rrd_t *rrd)
 {
     unsigned long i, ii;
-    int       rrd_file;
     rrd_value_t *unknown;
     int       unkn_cnt;
     rrd_file_t *rrd_file_dn;
     rrd_t     rrd_dn;
-    unsigned  flags = O_WRONLY | O_CREAT | O_TRUNC;
+    unsigned  rrd_flags = RRD_READWRITE | RRD_CREAT;
 
-#if defined(_WIN32) && !defined(__CYGWIN__) && !defined(__CYGWIN32__)
-    flags |= O_BINARY;
-#endif
-
-    if ((rrd_file = open(file_name, flags, 0666)) < 0) {
+    if ((rrd_file_dn = rrd_open(file_name, rrd, rrd_flags)) == NULL) {
         rrd_set_error("creating '%s': %s", file_name, rrd_strerror(errno));
         rrd_free2(rrd);
         return (-1);
     }
 
-    write(rrd_file, rrd->stat_head, sizeof(stat_head_t));
+    rrd_write(rrd_file_dn, rrd->stat_head, sizeof(stat_head_t));
 
-    write(rrd_file, rrd->ds_def, sizeof(ds_def_t) * rrd->stat_head->ds_cnt);
+    rrd_write(rrd_file_dn, rrd->ds_def, sizeof(ds_def_t) * rrd->stat_head->ds_cnt);
 
-    write(rrd_file, rrd->rra_def,
+    rrd_write(rrd_file_dn, rrd->rra_def,
           sizeof(rra_def_t) * rrd->stat_head->rra_cnt);
 
-    write(rrd_file, rrd->live_head, sizeof(live_head_t));
+    rrd_write(rrd_file_dn, rrd->live_head, sizeof(live_head_t));
 
     if ((rrd->pdp_prep = calloc(1, sizeof(pdp_prep_t))) == NULL) {
         rrd_set_error("allocating pdp_prep");
         rrd_free2(rrd);
-        close(rrd_file);
+        rrd_close(rrd_file_dn);
         return (-1);
     }
 
@@ -711,12 +706,12 @@
         rrd->live_head->last_up % rrd->stat_head->pdp_step;
 
     for (i = 0; i < rrd->stat_head->ds_cnt; i++)
-        write(rrd_file, rrd->pdp_prep, sizeof(pdp_prep_t));
+        rrd_write(rrd_file_dn, rrd->pdp_prep, sizeof(pdp_prep_t));
 
     if ((rrd->cdp_prep = calloc(1, sizeof(cdp_prep_t))) == NULL) {
         rrd_set_error("allocating cdp_prep");
         rrd_free2(rrd);
-        close(rrd_file);
+        rrd_close(rrd_file_dn);
         return (-1);
     }
 
@@ -753,7 +748,7 @@
         }
 
         for (ii = 0; ii < rrd->stat_head->ds_cnt; ii++) {
-            write(rrd_file, rrd->cdp_prep, sizeof(cdp_prep_t));
+            rrd_write(rrd_file_dn, rrd->cdp_prep, sizeof(cdp_prep_t));
         }
     }
 
@@ -763,7 +758,7 @@
     if ((rrd->rra_ptr = calloc(1, sizeof(rra_ptr_t))) == NULL) {
         rrd_set_error("allocating rra_ptr");
         rrd_free2(rrd);
-        close(rrd_file);
+        rrd_close(rrd_file_dn);
         return (-1);
     }
 
@@ -773,14 +768,14 @@
      * the pointer a priori. */
     for (i = 0; i < rrd->stat_head->rra_cnt; i++) {
         rrd->rra_ptr->cur_row = rra_random_row(&rrd->rra_def[i]);
-        write(rrd_file, rrd->rra_ptr, sizeof(rra_ptr_t));
+        rrd_write(rrd_file_dn, rrd->rra_ptr, sizeof(rra_ptr_t));
     }
 
     /* write the empty data area */
     if ((unknown = (rrd_value_t *) malloc(512 * sizeof(rrd_value_t))) == NULL) {
         rrd_set_error("allocating unknown");
         rrd_free2(rrd);
-        close(rrd_file);
+        rrd_close(rrd_file_dn);
         return (-1);
     }
     for (i = 0; i < 512; ++i)
@@ -791,22 +786,27 @@
         unkn_cnt += rrd->stat_head->ds_cnt * rrd->rra_def[i].row_cnt;
 
     while (unkn_cnt > 0) {
-        write(rrd_file, unknown, sizeof(rrd_value_t) * min(unkn_cnt, 512));
+        if(rrd_write(rrd_file_dn, unknown, sizeof(rrd_value_t) * min(unkn_cnt, 512)) < 0)
+        {
+            rrd_set_error("creating rrd: %s", rrd_strerror(errno));
+            return -1;
+        }
 
         unkn_cnt -= 512;
     }
     free(unknown);
-    fdatasync(rrd_file);
     rrd_free2(rrd);
-    if (close(rrd_file) == -1) {
+    if (rrd_close(rrd_file_dn) == -1) {
         rrd_set_error("creating rrd: %s", rrd_strerror(errno));
         return -1;
     }
     /* flush all we don't need out of the cache */
-    rrd_file_dn = rrd_open(file_name, &rrd_dn, RRD_READONLY);
-    rrd_dontneed(rrd_file_dn, &rrd_dn);
-    rrd_free(&rrd_dn);
-    rrd_close(rrd_file_dn);
+    if((rrd_file_dn = rrd_open(file_name, &rrd_dn, RRD_READONLY)) != NULL)
+    {
+        rrd_dontneed(rrd_file_dn, &rrd_dn);
+        /* rrd_free(&rrd_dn); */
+        rrd_close(rrd_file_dn);
+    }
     return (0);
 }
 
Index: src/rrd_tool.h
===================================================================
--- src/rrd_tool.h	(revision 1598)
+++ src/rrd_tool.h	(working copy)
@@ -97,6 +97,7 @@
 #define RRD_CREAT       (1<<2)
 #define RRD_READAHEAD   (1<<3)
 #define RRD_COPY        (1<<4)
+#define RRD_CREAT_SETSIZE (1<<5)
 
     enum cf_en cf_conv(
     const char *string);
Index: src/rrd_open.c
===================================================================
--- src/rrd_open.c	(revision 1598)
+++ src/rrd_open.c	(working copy)
@@ -79,13 +79,14 @@
     rrd_file_t *rrd_file = NULL;
     off_t     newfile_size = 0;
 
-    if (rdwr & RRD_CREAT) {
+    if ((rdwr & RRD_CREAT) && (rdwr & RRD_CREAT_SETSIZE)) {
         /* yes bad inline signaling alert, we are using the
            floatcookie to pass the size in ... only used in resize */
         newfile_size = (off_t) rrd->stat_head->float_cookie;
         free(rrd->stat_head);
     }
-    rrd_init(rrd);
+    if(!(rdwr & RRD_CREAT))
+        rrd_init(rrd);
     rrd_file = malloc(sizeof(rrd_file_t));
     if (rrd_file == NULL) {
         rrd_set_error("allocating rrd_file descriptor for '%s'", file_name);
@@ -170,7 +171,13 @@
            }
         }
 */
+
 #ifdef HAVE_MMAP
+    if(rrd_file->file_len == 0 && (rdwr & RRD_CREAT))
+    {
+        rrd_file->file_start = NULL;
+        goto out_done;
+    }
     data = mmap(0, rrd_file->file_len, mm_prot, mm_flags,
                 rrd_file->fd, offset);
 
@@ -535,10 +542,36 @@
     size_t count)
 {
 #ifdef HAVE_MMAP
+    /* These flags are used if creating a new RRD */
+    int       mm_prot = PROT_READ | PROT_WRITE, mm_flags = MAP_SHARED;
+    int old_size = rrd_file->file_len;
+    int new_size = rrd_file->file_len;
     if (count == 0)
         return 0;
     if (buf == NULL)
         return -1;      /* EINVAL */
+    
+    if((rrd_file->pos + count) > old_size)
+    {
+        new_size = rrd_file->pos + count; 
+        rrd_file->file_len = new_size;
+        lseek(rrd_file->fd, new_size - 1, SEEK_SET);
+        write(rrd_file->fd, "\0", 1);   /* poke */
+        lseek(rrd_file->fd, 0, SEEK_SET);
+        if(rrd_file->file_start == NULL)
+        {
+            rrd_file->file_start = mmap(0, new_size, mm_prot, mm_flags,
+                rrd_file->fd, 0);
+        }
+        else
+            rrd_file->file_start = mremap(rrd_file->file_start, old_size, new_size, MREMAP_MAYMOVE); 
+
+        if (rrd_file->file_start == MAP_FAILED) {
+            rrd_set_error("m(re)maping file : %s", 
+                      rrd_strerror(errno));
+            return -1;
+        }
+    }
     memcpy(rrd_file->file_start + rrd_file->pos, buf, count);
     rrd_file->pos += count;
     return count;       /* mimmic write() semantics */
