From 72ffaae5e4824671aec0ec3643663a13450c3a44 Mon Sep 17 00:00:00 2001
From: Robert Wang <wdongxu@linux.vnet.ibm.com>
Date: Tue, 9 Aug 2011 16:13:17 +0800
Subject: [PATCH] block.c

---
 block.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 57 insertions(+), 3 deletions(-)

diff --git a/block.c b/block.c
index 26910ca143..41da58980e 100644
--- a/block.c
+++ b/block.c
@@ -29,6 +29,7 @@
 #include "module.h"
 #include "qemu-objects.h"
 #include "qemu-coroutine.h"
+#include "block/add-cow.h"
 
 #ifdef CONFIG_BSD
 #include <sys/types.h>
@@ -324,12 +325,18 @@ static BlockDriver *find_hdev_driver(const char *filename)
     return drv;
 }
 
-BlockDriver *bdrv_find_protocol(const char *filename)
+BlockDriver *bdrv_find_protocol(const char *filename1)
 {
     BlockDriver *drv1;
     char protocol[128];
     int len;
     const char *p;
+    char *filename = NULL;
+    char *cow_file = NULL;
+    char filename_buff[1024];
+    snprintf(filename_buff,sizeof(filename_buff),"%s",filename1);
+    filename = strtok(filename_buff,":");
+    cow_file = strtok(NULL, ":" );
 
     /* TODO Drivers without bdrv_file_open must be specified explicitly */
 
@@ -370,8 +377,19 @@ static int find_image_format(const char *filename, BlockDriver **pdrv)
     BlockDriver *drv1, *drv;
     uint8_t buf[2048];
     BlockDriverState *bs;
+    char *image_file = NULL;
+    char *cow_file = NULL;
+    char filename_buff[1024];
+    snprintf(filename_buff,sizeof(filename_buff),"%s",filename);
+
+    image_file = strtok(filename_buff,":");
+    cow_file = strtok(NULL,":");
+
+    ret = bdrv_file_open(&bs, image_file, 0);
+
+    if(cow_file)
+        sprintf(bs->cow_file,"%s",cow_file);
 
-    ret = bdrv_file_open(&bs, filename, 0);
     if (ret < 0) {
         *pdrv = NULL;
         return ret;
@@ -547,10 +565,18 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
 /*
  * Opens a disk image (raw, qcow2, vmdk, ...)
  */
-int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
+int bdrv_open(BlockDriverState *bs, const char *filename1, int flags,
               BlockDriver *drv)
 {
     int ret;
+    char *filename = NULL;
+    char *cowfile = NULL;
+    struct add_cow_head header;
+
+    char filename_buff[1024];
+    snprintf(filename_buff,sizeof(filename_buff),"%s",filename1);
+    filename = strtok(filename_buff,":");
+    cowfile = strtok(NULL,":");
 
     if (flags & BDRV_O_SNAPSHOT) {
         BlockDriverState *bs1;
@@ -608,6 +634,12 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
         bs->is_temporary = 1;
     }
 
+    if(cowfile) {
+        snprintf(bs->cow_file, sizeof(bs->cow_file), "%s", cowfile);	
+        get_add_cow_head(cowfile, &header);
+        sprintf(bs->backing_file,"%s",header.backing_file);
+    }
+
     /* Find the right image format driver */
     if (!drv) {
         ret = find_image_format(filename, &drv);
@@ -3143,6 +3175,7 @@ int bdrv_img_create(const char *filename, const char *fmt,
     BlockDriver *drv, *proto_drv;
     BlockDriver *backing_drv = NULL;
     int ret = 0;
+    QEMUOptionParameter *cow_file;
 
     /* Find driver and parse its options */
     drv = bdrv_find_format(fmt);
@@ -3219,6 +3252,27 @@ int bdrv_img_create(const char *filename, const char *fmt,
         }
     }
 
+
+    // add cow support
+    if (!strcmp(fmt, "raw")) {
+        cow_file = get_option_parameter(param, BLOCK_OPT_COW_FILE);
+        if(cow_file->value.s && cow_file->value.s) {
+            if( !strcmp(cow_file->value.s,backing_file->value.s)) {
+                error_report("Error: Trying to create an cow file with the "
+                            "same filename as the backing file");
+                ret = -EINVAL;
+                goto out;
+            }
+
+            if( !strcmp(cow_file->value.s, filename)) {
+                error_report("Error: Trying to create an cow file with the "
+                          "same filename as the image file");
+                ret = -EINVAL;
+                goto out;
+            }
+        }
+    }
+
     // The size for the image must always be specified, with one exception:
     // If we are using a backing file, we can obtain the size from there
     size = get_option_parameter(param, BLOCK_OPT_SIZE);
-- 
2.11.4.GIT