[Qemu-devel] [PATCH 1/2] block: clean up bdrv_open2 structure a bit

[Christoph Hellwig <hch@lst.de>]

Check the whitelist as early as possible instead of continuing the
setup, and move all the error handling code to the end of the
function.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: qemu/block.c
===================================================================
--- qemu.orig/block.c	2010-01-11 17:48:27.811004054 +0100
+++ qemu/block.c	2010-01-11 17:52:15.578006158 +0100
@@ -428,10 +428,16 @@ int bdrv_open2(BlockDriverState *bs, con
             drv = find_image_format(filename);
         }
     }
+
     if (!drv) {
         ret = -ENOENT;
         goto unlink_and_fail;
     }
+    if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv)) {
+        ret = -ENOTSUP;
+        goto unlink_and_fail;
+    }
+
     bs->drv = drv;
     bs->opaque = qemu_mallocz(drv->instance_size);
 
@@ -452,23 +458,17 @@ int bdrv_open2(BlockDriverState *bs, con
             (flags & (BDRV_O_CACHE_MASK|BDRV_O_NATIVE_AIO));
     else
         open_flags = flags & ~(BDRV_O_FILE | BDRV_O_SNAPSHOT);
-    if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv))
-        ret = -ENOTSUP;
-    else
-        ret = drv->bdrv_open(bs, filename, open_flags);
+
+    ret = drv->bdrv_open(bs, filename, open_flags);
     if ((ret == -EACCES || ret == -EPERM) && !(flags & BDRV_O_FILE)) {
         ret = drv->bdrv_open(bs, filename, open_flags & ~BDRV_O_RDWR);
         bs->read_only = 1;
     }
+
     if (ret < 0) {
-        qemu_free(bs->opaque);
-        bs->opaque = NULL;
-        bs->drv = NULL;
-    unlink_and_fail:
-        if (bs->is_temporary)
-            unlink(filename);
-        return ret;
+        goto free_and_fail;
     }
+
     if (drv->bdrv_getlength) {
         bs->total_sectors = bdrv_getlength(bs) >> BDRV_SECTOR_BITS;
     }
@@ -502,6 +502,15 @@ int bdrv_open2(BlockDriverState *bs, con
             bs->change_cb(bs->change_opaque);
     }
     return 0;
+
+free_and_fail:
+    qemu_free(bs->opaque);
+    bs->opaque = NULL;
+    bs->drv = NULL;
+unlink_and_fail:
+    if (bs->is_temporary)
+        unlink(filename);
+    return ret;
 }
 
 void bdrv_close(BlockDriverState *bs)