[PULL 2/2] block/export: call blk_set_dev_ops(blk, NULL, NULL)

[Eric Blake]

From: Stefan Hajnoczi <stefanha@redhat.com>

Most export types install BlockDeviceOps pointers. It is easy to forget
to remove them because that happens automatically via the "drive" qdev
property in hw/ but not block/export/.

Put blk_set_dev_ops(blk, NULL, NULL) calls in the core export.c code so
the export types don't need to remember.

This fixes the nbd and vhost-user-blk export types.

Fixes: fd6afc501a01 ("nbd/server: Use drained block ops to quiesce the server")
Fixes: ca858a5fe94c ("vhost-user-blk-server: notify client about disk resize")
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20230502211119.720647-1-stefanha@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/export/export.c    | 2 ++
 block/export/vduse-blk.c | 1 -
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/export/export.c b/block/export/export.c
index e3fee606116..62c7c22d45d 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -192,6 +192,7 @@ BlockExport *blk_exp_add(BlockExportOptions *export, Error 
**errp)
     return exp;

 fail:
+    blk_set_dev_ops(exp->blk, NULL, NULL);
     blk_unref(blk);
     aio_context_release(ctx);
     if (exp) {
@@ -219,6 +220,7 @@ static void blk_exp_delete_bh(void *opaque)
     assert(exp->refcount == 0);
     QLIST_REMOVE(exp, next);
     exp->drv->delete(exp);
+    blk_set_dev_ops(exp->blk, NULL, NULL);
     blk_unref(exp->blk);
     qapi_event_send_block_export_deleted(exp->id);
     g_free(exp->id);
diff --git a/block/export/vduse-blk.c b/block/export/vduse-blk.c
index f7ae44e3cea..b53ef39da02 100644
--- a/block/export/vduse-blk.c
+++ b/block/export/vduse-blk.c
@@ -346,7 +346,6 @@ static void vduse_blk_exp_delete(BlockExport *exp)

     blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
                                     vblk_exp);
-    blk_set_dev_ops(exp->blk, NULL, NULL);
     ret = vduse_dev_destroy(vblk_exp->dev);
     if (ret != -EBUSY) {
         unlink(vblk_exp->recon_file);
-- 
2.40.1