On Mon, 14 Sep 2015 17:39:54 +0100 Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > On Mon, Sep 14, 2015 at 10:19:18AM -0400, Jeff Layton wrote: > > > > + * borrow the infrastructure used by kthreads, and the task can then just > > > > + * called flush_delayed_fput to ensure that the final fput has completed. > > > > > > Are you sure that it's not a typo? > > > > I don't think so, but it could be clearer. Something like this maybe? > > > > "then we can't queue it via task_work_add." > > Huh? > > task_work_add() callbacks *will* run before we return to userland Right, but only just before. We need it to run before we try to set the lease in the context of a fcntl() call. How about this text instead then? I'll fix up the patch if this sounds reasonable: "When fput is called in the context of a userland process, it'll queue the actual work (__fput()) to be done just before returning to userland. In some cases however, we need to ensure that the __fput runs before that point. There is no safe way to flush work that has been queued via task_work_add however, so to do this we borrow the delayed_fput infrastructure that kthreads use. The userland process can use fput_queue() on one or more struct files and then call flush_delayed_fput() to ensure that they are completely closed." -- Jeff Layton <jlayton@xxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
