fuse: wakeup pollers on connection release/abort

If a fuse dev connection is broken, wake up any
processes that are blocking, in a poll system call,
on one of the files in the now defunct filesystem.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index cf8d28d..213d3cf 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1910,6 +1910,21 @@
 		kfree(dequeue_forget(fc, 1, NULL));
 }
 
+static void end_polls(struct fuse_conn *fc)
+{
+	struct rb_node *p;
+
+	p = rb_first(&fc->polled_files);
+
+	while (p) {
+		struct fuse_file *ff;
+		ff = rb_entry(p, struct fuse_file, polled_node);
+		wake_up_interruptible_all(&ff->poll_wait);
+
+		p = rb_next(p);
+	}
+}
+
 /*
  * Abort all requests.
  *
@@ -1937,6 +1952,7 @@
 		fc->blocked = 0;
 		end_io_requests(fc);
 		end_queued_requests(fc);
+		end_polls(fc);
 		wake_up_all(&fc->waitq);
 		wake_up_all(&fc->blocked_waitq);
 		kill_fasync(&fc->fasync, SIGIO, POLL_IN);
@@ -1953,6 +1969,7 @@
 		fc->connected = 0;
 		fc->blocked = 0;
 		end_queued_requests(fc);
+		end_polls(fc);
 		wake_up_all(&fc->blocked_waitq);
 		spin_unlock(&fc->lock);
 		fuse_conn_put(fc);