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>

Author: Bryan Green

fs/fuse/dev.c

@@ -1910,6 +1910,21 @@ __acquires(fc->lock)
 		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 @@ void fuse_abort_conn(struct fuse_conn *fc)
 		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 @@ int fuse_dev_release(struct inode *inode, struct file *file)
 		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);

fs/fuse/file.c

@@ -222,7 +222,7 @@ static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
 		rb_erase(&ff->polled_node, &fc->polled_files);
 	spin_unlock(&fc->lock);
 
-	wake_up_interruptible_sync(&ff->poll_wait);
+	wake_up_interruptible_all(&ff->poll_wait);
 
 	inarg->fh = ff->fh;
 	inarg->flags = flags;