[Qemu-devel] [PATCH V4 3/5] block: Check infinite loop in bdrv_img_create()

[Xu Wang]

Backing file loop should be checked before qemu-img create command
execution. If loop was found, qemu-img create should be stopped and
an error was printed.

Signed-off-by: Xu Wang <address@hidden>
---
 block.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/block.c b/block.c
index 3e23b67..9daf63c 100644
--- a/block.c
+++ b/block.c
@@ -4735,15 +4735,15 @@ void bdrv_img_create(const char *filename, const char 
*fmt,
     }
 
     backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
+    backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT);
     if (backing_file && backing_file->value.s) {
-        if (!strcmp(filename, backing_file->value.s)) {
-            error_setg(errp, "Error: Trying to create an image with the "
-                             "same filename as the backing file");
+        if (bdrv_backing_file_loop_check(filename, fmt,
+                                         backing_file->value.s,
+                                         backing_fmt->value.s)) {
+            /* There is loop exists in the backing file chain */
             goto out;
         }
     }
-
-    backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT);
     if (backing_fmt && backing_fmt->value.s) {
         backing_drv = bdrv_find_format(backing_fmt->value.s);
         if (!backing_drv) {
-- 
1.8.1.4