Make sure disk writes really made it to disk before we report I/O
completion to the guest domain.  The DMA_MULTI_THREAD functionality
from the qemu-dm IDE emulation should make the performance overhead
of synchronous writes bearable, or at least comparable to native
hardware.

Signed-off-by: Rik van Riel <riel@redhat.com>

--- xen-unstable-10712/tools/ioemu/block-bochs.c.osync	2006-07-28 02:15:56.000000000 -0400
+++ xen-unstable-10712/tools/ioemu/block-bochs.c	2006-07-28 02:21:08.000000000 -0400
@@ -91,7 +91,7 @@
     int fd, i;
     struct bochs_header bochs;
 
-    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
+    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE | O_SYNC);
     if (fd < 0) {
         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
         if (fd < 0)
--- xen-unstable-10712/tools/ioemu/block.c.osync	2006-07-28 02:15:56.000000000 -0400
+++ xen-unstable-10712/tools/ioemu/block.c	2006-07-28 02:19:27.000000000 -0400
@@ -677,7 +677,7 @@
     int rv;
 #endif
 
-    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
+    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE | O_SYNC);
     if (fd < 0) {
         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
         if (fd < 0)
--- xen-unstable-10712/tools/ioemu/block-cloop.c.osync	2006-07-28 02:15:56.000000000 -0400
+++ xen-unstable-10712/tools/ioemu/block-cloop.c	2006-07-28 02:17:13.000000000 -0400
@@ -55,7 +55,7 @@
     BDRVCloopState *s = bs->opaque;
     uint32_t offsets_size,max_compressed_block_size=1,i;
 
-    s->fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
+    s->fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE | O_SYNC);
     if (s->fd < 0)
         return -1;
     bs->read_only = 1;
--- xen-unstable-10712/tools/ioemu/block-cow.c.osync	2006-07-28 02:15:56.000000000 -0400
+++ xen-unstable-10712/tools/ioemu/block-cow.c	2006-07-28 02:21:34.000000000 -0400
@@ -69,7 +69,7 @@
     struct cow_header_v2 cow_header;
     int64_t size;
 
-    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
+    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE | O_SYNC);
     if (fd < 0) {
         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
         if (fd < 0)
--- xen-unstable-10712/tools/ioemu/block-qcow.c.osync	2006-07-28 02:15:56.000000000 -0400
+++ xen-unstable-10712/tools/ioemu/block-qcow.c	2006-07-28 02:20:05.000000000 -0400
@@ -95,7 +95,7 @@
     int fd, len, i, shift;
     QCowHeader header;
     
-    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
+    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE | O_SYNC);
     if (fd < 0) {
         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
         if (fd < 0)
--- xen-unstable-10712/tools/ioemu/block-vmdk.c.osync	2006-07-28 02:15:56.000000000 -0400
+++ xen-unstable-10712/tools/ioemu/block-vmdk.c	2006-07-28 02:20:20.000000000 -0400
@@ -96,7 +96,7 @@
     uint32_t magic;
     int l1_size;
 
-    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE);
+    fd = open(filename, O_RDWR | O_BINARY | O_LARGEFILE | O_SYNC);
     if (fd < 0) {
         fd = open(filename, O_RDONLY | O_BINARY | O_LARGEFILE);
         if (fd < 0)