fix rrd_create behaviour when mmaping on a full filesystem by actually 'filling'...

[rrdtool.git] / src / rrd_open.c

diff --git a/src/rrd_open.c b/src/rrd_open.c
index 7c508ff..117c79c 100644 (file)
--- a/src/rrd_open.c
+++ b/src/rrd_open.c
@@ -248,6 +248,38 @@ rrd_file_t *rrd_open(
 */
 
 #ifdef HAVE_MMAP
+       /* force allocating the file on the underlaying filesystem to prevent any
+        * future bus error when the filesystem is full and attempting to write
+        * trough the file mapping. Filling the file using memset on the file
+        * mapping can also lead some bus error, so we use the old fashioned
+        * write().
+        */
+    if (rdwr & RRD_CREAT) {
+               char     buf[4096];
+               unsigned i;
+
+               memset(buf, DNAN, sizeof buf);
+               lseek(rrd_simple_file->fd, offset, SEEK_SET);
+        
+               for (i = 0; i < (newfile_size - 1) / sizeof buf; ++i)
+               {
+                       if (write(rrd_simple_file->fd, buf, sizeof buf) == -1)
+                       {
+                               rrd_set_error("write '%s': %s", file_name, rrd_strerror(errno));
+                               goto out_close;
+                       }
+               }
+               
+               if (write(rrd_simple_file->fd, buf,
+                                       (newfile_size - 1) % sizeof buf) == -1)
+               {
+                       rrd_set_error("write '%s': %s", file_name, rrd_strerror(errno));
+                       goto out_close;
+               }
+
+               lseek(rrd_simple_file->fd, 0, SEEK_SET);
+    }
+
     data = mmap(0, rrd_file->file_len, 
         rrd_simple_file->mm_prot, rrd_simple_file->mm_flags,
         rrd_simple_file->fd, offset);
@@ -260,7 +292,6 @@ rrd_file_t *rrd_open(
     }
     rrd_simple_file->file_start = data;
     if (rdwr & RRD_CREAT) {
-        memset(data, DNAN, newfile_size - 1);
         goto out_done;
     }
 #endif