On 2015-01-28 at 17:44, Eric Blake wrote:
On 01/26/2015 12:27 PM, Max Reitz wrote:
Every time a reference to a BlockBackend is taken, a notifier for
bdrv_close_all() has to be deposited so the reference holder can
relinquish its reference when bdrv_close_all() is called. That notifier
should be revoked on a bdrv_unref() call.
In addition to the design question about whether NBD exports should be
their own new BB,
@@ -198,8 +207,12 @@ void blk_ref(BlockBackend *blk)
* If this drops it to zero, destroy @blk.
* For convenience, do nothing if @blk is null.
*/
-void blk_unref(BlockBackend *blk)
+void blk_unref(BlockBackend *blk, Notifier *close_all_notifier)
{
+ if (close_all_notifier) {
+ notifier_remove(close_all_notifier);
+ }
+
if (blk) {
Does removing a notifier when blk is NULL make sense?
Considering the pattern is probably "allocate notifier; if that fails,
goto fail; create BB; if that fails, goto fail; ...; fail: blk_unref();
free notifier", the is indeed a case where the notifier may be non-NULL
but not yet registered (if "create BB" failed). Therefore, to simplify
the caller code, notifier_remove() should only be called if blk is not
NULL, right.
Will fix.
Max
