From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Date: Thu, 2 Dec 2010 16:54:13 +0000 (+0000)
Subject: block: Fix the use of protocols in backing files
X-Git-Tag: v0.14.0-rc0~347
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=df2dbb4a508ebea7bcacff3f07caecbae969d528;p=thirdparty%2Fqemu.git

block: Fix the use of protocols in backing files

Backing filenames may contain a protocol.  The code currently doesn't
consider this case and produces filenames that embed "<protocol>:".
Don't combine filenames if the backing filename contains a protocol.

Based on an earlier patch by Anthony Liguori <aliguori@us.ibm.com>.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---

diff --git a/block.c b/block.c
index 65fce8031a9..b4aaf416401 100644
--- a/block.c
+++ b/block.c
@@ -611,10 +611,18 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
         BlockDriver *back_drv = NULL;
 
         bs->backing_hd = bdrv_new("");
-        path_combine(backing_filename, sizeof(backing_filename),
-                     filename, bs->backing_file);
-        if (bs->backing_format[0] != '\0')
+
+        if (path_has_protocol(bs->backing_file)) {
+            pstrcpy(backing_filename, sizeof(backing_filename),
+                    bs->backing_file);
+        } else {
+            path_combine(backing_filename, sizeof(backing_filename),
+                         filename, bs->backing_file);
+        }
+
+        if (bs->backing_format[0] != '\0') {
             back_drv = bdrv_find_format(bs->backing_format);
+        }
 
         /* backing files always opened read-only */
         back_flags =