Index: lighttpd-1.4.x/src/mod_compress.c
===================================================================
--- lighttpd-1.4.x/src/mod_compress.c	(revision 2364)
+++ lighttpd-1.4.x/src/mod_compress.c	(working copy)
@@ -410,6 +410,7 @@
 	void *start;
 	const char *filename = fn->ptr;
 	ssize_t r;
+	struct stat sb;
 
 	/* overflow */
 	if ((off_t)(sce->st.st_size * 1.1) < sce->st.st_size) return -1;
@@ -485,8 +486,24 @@
 		return -1;
 	}
 
+	if (-1 == fstat(ifd, &sb)) {
+		log_error_write(srv, __FILE__, __LINE__, "sbss", "fstat of plain-file", fn, "failed", strerror(errno));
+		close(ofd);
+		close(ifd);
 
-	if (MAP_FAILED == (start = mmap(NULL, sce->st.st_size, PROT_READ, MAP_SHARED, ifd, 0))) {
+		return -1;
+	}
+
+	if (sb.st_ino != sce->st.st_ino || sb.st_dev != sce->st.st_dev || sb.st_mode != sce->st.st_mode || sb.st_size != sce->st.st_size) {
+		/* File changed */
+
+		close(ofd);
+		close(ifd);
+		return -1;
+	}
+
+
+	if (MAP_FAILED == (start = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, ifd, 0))) {
 		log_error_write(srv, __FILE__, __LINE__, "sbss", "mmaping", fn, "failed", strerror(errno));
 
 		close(ofd);
@@ -503,15 +520,15 @@
 	switch(type) {
 #ifdef USE_ZLIB
 	case HTTP_ACCEPT_ENCODING_GZIP:
-		ret = deflate_file_to_buffer_gzip(srv, con, p, start, sce->st.st_size, sce->st.st_mtime);
+		ret = deflate_file_to_buffer_gzip(srv, con, p, start, sb.st_size, sb.st_mtime);
 		break;
 	case HTTP_ACCEPT_ENCODING_DEFLATE:
-		ret = deflate_file_to_buffer_deflate(srv, con, p, start, sce->st.st_size);
+		ret = deflate_file_to_buffer_deflate(srv, con, p, start, sb.st_size);
 		break;
 #endif
 #ifdef USE_BZ2LIB
 	case HTTP_ACCEPT_ENCODING_BZIP2:
-		ret = deflate_file_to_buffer_bzip2(srv, con, p, start, sce->st.st_size);
+		ret = deflate_file_to_buffer_bzip2(srv, con, p, start, sb.st_size);
 		break;
 #endif
 	default:
@@ -530,7 +547,7 @@
 		}
 	}
 
-	munmap(start, sce->st.st_size);
+	munmap(start, sb.st_size);
 	close(ofd);
 	close(ifd);
 
@@ -553,6 +570,7 @@
 	int ret = -1;
 	void *start;
 	buffer *b;
+	struct stat sb;
 
 	/* overflow */
 	if ((off_t)(sce->st.st_size * 1.1) < sce->st.st_size) return -1;
@@ -571,8 +589,21 @@
 		return -1;
 	}
 
+	if (-1 == fstat(ifd, &sb)) {
+		log_error_write(srv, __FILE__, __LINE__, "sbss", "fstat of plain-file", fn, "failed", strerror(errno));
+		close(ifd);
 
-	if (MAP_FAILED == (start = mmap(NULL, sce->st.st_size, PROT_READ, MAP_SHARED, ifd, 0))) {
+		return -1;
+	}
+
+	if (sb.st_ino != sce->st.st_ino || sb.st_dev != sce->st.st_dev || sb.st_mode != sce->st.st_mode || sb.st_size != sce->st.st_size) {
+		/* File changed */
+
+		close(ifd);
+		return -1;
+	}
+
+	if (MAP_FAILED == (start = mmap(NULL, sb.st_size, PROT_READ, MAP_PRIVATE, ifd, 0))) {
 		log_error_write(srv, __FILE__, __LINE__, "sbss", "mmaping", fn, "failed", strerror(errno));
 
 		close(ifd);
@@ -582,15 +613,15 @@
 	switch(type) {
 #ifdef USE_ZLIB
 	case HTTP_ACCEPT_ENCODING_GZIP:
-		ret = deflate_file_to_buffer_gzip(srv, con, p, start, sce->st.st_size, sce->st.st_mtime);
+		ret = deflate_file_to_buffer_gzip(srv, con, p, start, sb.st_size, sb.st_mtime);
 		break;
 	case HTTP_ACCEPT_ENCODING_DEFLATE:
-		ret = deflate_file_to_buffer_deflate(srv, con, p, start, sce->st.st_size);
+		ret = deflate_file_to_buffer_deflate(srv, con, p, start, sb.st_size);
 		break;
 #endif
 #ifdef USE_BZ2LIB
 	case HTTP_ACCEPT_ENCODING_BZIP2:
-		ret = deflate_file_to_buffer_bzip2(srv, con, p, start, sce->st.st_size);
+		ret = deflate_file_to_buffer_bzip2(srv, con, p, start, sb.st_size);
 		break;
 #endif
 	default:
@@ -598,7 +629,7 @@
 		break;
 	}
 
-	munmap(start, sce->st.st_size);
+	munmap(start, sb.st_size);
 	close(ifd);
 
 	if (ret != 0) return -1;