Hello, Jan. On Mon, Nov 28, 2016 at 11:07:18AM +0100, Jan Kara wrote: > As I'm looking into the code, we need a serialization between bdev writeback > and blkdev_put(). That should be doable if we use writeback_single_inode() > for writing bdev inode instead of simple filemap_fdatawrite() and then use > inode_wait_for_writeback() in blkdev_put() but it needs some careful > thought. It's kinda weird that sync() is ends up accessing bdev's without any synchronization. Can't we just make iterate_bdevs() grab bd_mutex and verify bd_disk isn't NULL before calling into the callback? > Frankly that whole idea of tearing block devices down on last close is a > major headache and keeps biting us. I'm wondering whether it is still worth > it these days... Yeah, it'd be great if we can follow a more conventional lifetime pattern here. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>