From: oetiker <oetiker@a5681a0c-68f1-0310-ab6d-d61299d08faa>
Date: Thu, 21 Apr 2011 06:12:50 +0000 (+0000)
Subject: fix rrd_create behaviour when mmaping on a full filesystem by actually 'filling'... 
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=f6728e9f118acf468a33972792e3a851785bcb8a;p=rrdtool.git

fix rrd_create behaviour when mmaping on a full filesystem by actually 'filling' the file with
zero. -- Francois-Xavier Bourlet francois-xavier.bourlet dotcloud.com


git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@2181 a5681a0c-68f1-0310-ab6d-d61299d08faa
---

diff --git a/src/rrd_open.c b/src/rrd_open.c
index 7c508ff..117c79c 100644
--- 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