block: Fix error path in bdrv_backing_update_filename()

kevmw · kevmw · commit 6473069416dd · 2017-11-17T13:35:59.000+01:00
error_setg_errno() takes a positive errno code. Spotted by Coverity
(CID 1381628).

Signed-off-by: Kevin Wolf &lt;kwolf@redhat.com&gt;
Reviewed-by: Alberto Garcia &lt;berto@igalia.com&gt;
Reviewed-by: Eric Blake &lt;eblake@redhat.com&gt;
Reviewed-by: Stefan Hajnoczi &lt;stefanha@redhat.com&gt;
diff --git a/block.c b/block.c
@@ -998,7 +998,7 @@ static int bdrv_backing_update_filename(BdrvChild *c, BlockDriverState *base,
     ret = bdrv_change_backing_file(parent, filename,
                                    base->drv ? base->drv->format_name : "");
     if (ret < 0) {
-        error_setg_errno(errp, ret, "Could not update backing file link");
+        error_setg_errno(errp, -ret, "Could not update backing file link");
     }
 
     if (!(orig_flags & BDRV_O_RDWR)) {

Original file line number	Diff line number	Diff line change
`@@ -998,7 +998,7 @@ static int bdrv_backing_update_filename(BdrvChild c, BlockDriverState base,`
`998`	`998`	`ret = bdrv_change_backing_file(parent, filename,`
`999`	`999`	`base->drv ? base->drv->format_name : "");`
`1000`	`1000`	`if (ret < 0) {`
`1001`		`- error_setg_errno(errp, ret, "Could not update backing file link");`
	`1001`	`+ error_setg_errno(errp, -ret, "Could not update backing file link");`
`1002`	`1002`	`}`
`1003`	`1003`
`1004`	`1004`	`if (!(orig_flags & BDRV_O_RDWR)) {`