fuse: add req flag for private list

When an unlocked request is aborted, it is moved from fpq->io to a private
list.  Then, after unlocking fpq->lock, the private list is processed and
the requests are finished off.

To protect the private list, we need to mark the request with a flag, so if
in the meantime the request is unlocked the list is not corrupted.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

fs/fuse/fuse_i.h

@@ -269,6 +269,7 @@ struct fuse_io_priv {
  * FR_PENDING:		request is not yet in userspace
  * FR_SENT:		request is in userspace, waiting for an answer
  * FR_FINISHED:		request is finished
+ * FR_PRIVATE:		request is on private list
  */
 enum fuse_req_flag {
 	FR_ISREPLY,
@@ -281,6 +282,7 @@ enum fuse_req_flag {
 	FR_PENDING,
 	FR_SENT,
 	FR_FINISHED,
+	FR_PRIVATE,
 };
 
 /**