locks: add new struct list_head to struct file_lock

...that we can use to queue file_locks to per-ctx list_heads. Go ahead
and convert locks_delete_lock and locks_dispose_list to use it instead
of the fl_block list.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Acked-by: Christoph Hellwig <hch@lst.de>

2 files changed, 6 insertions, 3 deletions

diff --git a/fs/locks.c b/fs/locks.c
index 59e2f905e4ff..bfe5f17401de 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -207,6 +207,7 @@ static struct kmem_cache *filelock_cache __read_mostly;
 static void locks_init_lock_heads(struct file_lock *fl)
 {
         INIT_HLIST_NODE(&fl->fl_link);
+        INIT_LIST_HEAD(&fl->fl_list);
         INIT_LIST_HEAD(&fl->fl_block);
         init_waitqueue_head(&fl->fl_wait);
 }
@@ -243,6 +244,7 @@ EXPORT_SYMBOL_GPL(locks_release_private);
 void locks_free_lock(struct file_lock *fl)
 {
         BUG_ON(waitqueue_active(&fl->fl_wait));
+        BUG_ON(!list_empty(&fl->fl_list));
         BUG_ON(!list_empty(&fl->fl_block));
         BUG_ON(!hlist_unhashed(&fl->fl_link));
 
@@ -257,8 +259,8 @@ locks_dispose_list(struct list_head *dispose)
         struct file_lock *fl;
 
         while (!list_empty(dispose)) {
-                fl = list_first_entry(dispose, struct file_lock, fl_block);
-                list_del_init(&fl->fl_block);
+                fl = list_first_entry(dispose, struct file_lock, fl_list);
+                list_del_init(&fl->fl_list);
                 locks_free_lock(fl);
         }
 }
@@ -691,7 +693,7 @@ static void locks_delete_lock(struct file_lock **thisfl_p,
 
         locks_unlink_lock(thisfl_p);
         if (dispose)
-                list_add(&fl->fl_block, dispose);
+                list_add(&fl->fl_list, dispose);
         else
                 locks_free_lock(fl);
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 42efe13077b6..cd6818115162 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -934,6 +934,7 @@ int locks_in_grace(struct net *);
  */
 struct file_lock {
         struct file_lock *fl_next;      /* singly linked list for this inode  */
+        struct list_head fl_list;       /* link into file_lock_context */
         struct hlist_node fl_link;      /* node in global lists */
         struct list_head fl_block;      /* circular list of blocked processes */
         fl_owner_t fl_owner;