[PATCH 2/9] UML - Fix off-by-one bug in VM file creation

[Jeff Dike]

Fix an off-by-one bug in temp file creation.  Seeking to the desired
length and writing a byte resulted in the file being one byte longer
than expected.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>

Index: linux-2.6.17/arch/um/os-Linux/mem.c
===================================================================
--- linux-2.6.17.orig/arch/um/os-Linux/mem.c	2006-06-29 10:42:11.000000000 -0400
+++ linux-2.6.17/arch/um/os-Linux/mem.c	2006-06-29 11:42:23.000000000 -0400
@@ -210,8 +210,11 @@ int create_tmp_file(unsigned long long l
 		exit(1);
 	}
 
-        if (lseek64(fd, len, SEEK_SET) < 0) {
- 		perror("os_seek_file");
+	/* Seek to len - 1 because writing a character there will
+	 * increase the file size by one byte, to the desired length.
+	 */
+	if (lseek64(fd, len - 1, SEEK_SET) < 0) {
+		perror("os_seek_file");
 		exit(1);
 	}
 

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