server: Add a generic wait queue to the file descriptor object.

server/fd.c

diff --git a/server/fd.c b/server/fd.c
index 6fe4ace..d353aca 100644
--- a/server/fd.c
+++ b/server/fd.c
@@ -173,6 +173,7 @@
     int                  poll_index;  /* index of fd in poll array */
     struct list          read_q;      /* async readers of this fd */
     struct list          write_q;     /* async writers of this fd */
+    struct list          wait_q;      /* other async waiters of this fd */
 };
 
 static void fd_dump( struct object *obj, int verbose );
@@ -1287,6 +1288,7 @@
 
     async_terminate_queue( &fd->read_q, STATUS_CANCELLED );
     async_terminate_queue( &fd->write_q, STATUS_CANCELLED );
+    async_terminate_queue( &fd->wait_q, STATUS_CANCELLED );
 
     remove_fd_locks( fd );
     list_remove( &fd->inode_entry );
@@ -1365,6 +1367,7 @@
     list_init( &fd->locks );
     list_init( &fd->read_q );
     list_init( &fd->write_q );
+    list_init( &fd->wait_q );
 
     if ((fd->poll_index = add_poll_user( fd )) == -1)
     {
@@ -1395,6 +1398,7 @@
     list_init( &fd->locks );
     list_init( &fd->read_q );
     list_init( &fd->write_q );
+    list_init( &fd->wait_q );
     return fd;
 }
 
@@ -1736,6 +1740,9 @@
     case ASYNC_TYPE_WRITE:
         queue = &fd->write_q;
         break;
+    case ASYNC_TYPE_WAIT:
+        queue = &fd->wait_q;
+        break;
     default:
         set_error( STATUS_INVALID_PARAMETER );
         return;
@@ -1751,6 +1758,42 @@
     set_fd_events( fd, fd->fd_ops->get_poll_events( fd ) );
 }
 
+void fd_async_terminate_head( struct fd *fd, int type, unsigned int status )
+{
+    switch (type)
+    {
+    case ASYNC_TYPE_READ:
+        async_terminate_head( &fd->read_q, status );
+        break;
+    case ASYNC_TYPE_WRITE:
+        async_terminate_head( &fd->write_q, status );
+        break;
+    case ASYNC_TYPE_WAIT:
+        async_terminate_head( &fd->wait_q, status );
+        break;
+    default:
+        assert(0);
+    }
+}
+
+void fd_async_terminate_queue( struct fd *fd, int type, unsigned int status )
+{
+    switch (type)
+    {
+    case ASYNC_TYPE_READ:
+        async_terminate_queue( &fd->read_q, status );
+        break;
+    case ASYNC_TYPE_WRITE:
+        async_terminate_queue( &fd->write_q, status );
+        break;
+    case ASYNC_TYPE_WAIT:
+        async_terminate_queue( &fd->wait_q, status );
+        break;
+    default:
+        assert(0);
+    }
+}
+
 void default_fd_queue_async( struct fd *fd, const async_data_t *data, int type, int count )
 {
     fd_queue_async_timeout( fd, data, type, count, NULL );
@@ -1760,6 +1803,7 @@
 {
     async_terminate_queue( &fd->read_q, STATUS_CANCELLED );
     async_terminate_queue( &fd->write_q, STATUS_CANCELLED );
+    async_terminate_queue( &fd->wait_q, STATUS_CANCELLED );
 }
 
 /* default flush() routine */

server/file.h

diff --git a/server/file.h b/server/file.h
index c43352a..507d14c 100644
--- a/server/file.h
+++ b/server/file.h
@@ -70,6 +70,8 @@
 extern void default_poll_event( struct fd *fd, int event );
 extern void fd_queue_async_timeout( struct fd *fd, const async_data_t *data, int type,
                                     int count, const struct timeval *timeout );
+extern void fd_async_terminate_head( struct fd *fd, int type, unsigned int status );
+extern void fd_async_terminate_queue( struct fd *fd, int type, unsigned int status );
 extern void default_fd_queue_async( struct fd *fd, const async_data_t *data, int type, int count );
 extern void default_fd_cancel_async( struct fd *fd );
 extern void no_flush( struct fd *fd, struct event **event );