fuse: fix reserved request wake up

Use wake_up_all instead of wake_up in put_reserved_req(), otherwise it is
possible that the right task is not woken up.

Also create a separate reserved_req_waitq in addition to the blocked_waitq,
since they fulfill totally separate functions.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fuse/dev.c

@@ -129,7 +129,7 @@ static struct fuse_req *get_reserved_req(struct fuse_conn *fc,
 	struct fuse_file *ff = file->private_data;
 
 	do {
-		wait_event(fc->blocked_waitq, ff->reserved_req);
+		wait_event(fc->reserved_req_waitq, ff->reserved_req);
 		spin_lock(&fc->lock);
 		if (ff->reserved_req) {
 			req = ff->reserved_req;
@@ -155,7 +155,7 @@ static void put_reserved_req(struct fuse_conn *fc, struct fuse_req *req)
 	fuse_request_init(req);
 	BUG_ON(ff->reserved_req);
 	ff->reserved_req = req;
-	wake_up(&fc->blocked_waitq);
+	wake_up_all(&fc->reserved_req_waitq);
 	spin_unlock(&fc->lock);
 	fput(file);
 }

fs/fuse/fuse_i.h

@@ -289,6 +289,9 @@ struct fuse_conn {
 	/** waitq for blocked connection */
 	wait_queue_head_t blocked_waitq;
 
+	/** waitq for reserved requests */
+	wait_queue_head_t reserved_req_waitq;
+
 	/** The next unique request id */
 	u64 reqctr;
 

fs/fuse/inode.c

@@ -232,6 +232,7 @@ static void fuse_put_super(struct super_block *sb)
 	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 	wake_up_all(&fc->waitq);
 	wake_up_all(&fc->blocked_waitq);
+	wake_up_all(&fc->reserved_req_waitq);
 	mutex_lock(&fuse_mutex);
 	list_del(&fc->entry);
 	fuse_ctl_remove_conn(fc);
@@ -410,6 +411,7 @@ static struct fuse_conn *new_conn(void)
 		atomic_set(&fc->count, 1);
 		init_waitqueue_head(&fc->waitq);
 		init_waitqueue_head(&fc->blocked_waitq);
+		init_waitqueue_head(&fc->reserved_req_waitq);
 		INIT_LIST_HEAD(&fc->pending);
 		INIT_LIST_HEAD(&fc->processing);
 		INIT_LIST_HEAD(&fc->io);