bdev: surface the error from sync_blockdev()

When freeze_super() is called, sync_filesystem() will be called which
calls sync_blockdev() and already surfaces any errors. Do the same for
block devices that aren't owned by a superblock and also for filesystems
that don't call sync_blockdev() internally but implicitly rely on
bdev_freeze() to do it.

Link: https://lore.kernel.org/r/20231024-vfs-super-freeze-v2-3-599c19f4faac@kernel.org
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>

block/bdev.c

@@ -245,7 +245,7 @@ int bdev_freeze(struct block_device *bdev)
 	bdev->bd_fsfreeze_sb = sb;
 
 sync:
-	sync_blockdev(bdev);
+	error = sync_blockdev(bdev);
 done:
 	mutex_unlock(&bdev->bd_fsfreeze_mutex);
 	return error;