diff --git a/CREDITS.txt b/CREDITS.txt
index 558e359..91ab093 100644
--- a/CREDITS.txt
+++ b/CREDITS.txt
@@ -109,6 +109,9 @@ Bug fixes:
 Bug fixes:
     Lauri Kasanen
 
+Bug fixes:
+    Andreas Karlsson
+
 Other stuff:
     Your name here! Patches go to icculus@icculus.org ...
 
diff --git a/platform/posix.c b/platform/posix.c
index 652d9f7..85568ea 100644
--- a/platform/posix.c
+++ b/platform/posix.c
@@ -390,7 +390,8 @@ int __PHYSFS_platformEOF(void *opaque)
 int __PHYSFS_platformFlush(void *opaque)
 {
     int fd = *((int *) opaque);
-    BAIL_IF_MACRO(fsync(fd) == -1, strerror(errno), 0);
+    if ((fcntl(fd, F_GETFL) & O_ACCMODE) != O_RDONLY)
+        BAIL_IF_MACRO(fsync(fd) == -1, strerror(errno), 0);
     return(1);
 } /* __PHYSFS_platformFlush */