ocfs2: Teach ocfs2_drop_lock() to use ->set_lvb() callback

With this, we don't need to pass an additional struct with function pointer.

Now that the callbacks are fully used, comment the remaining API.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 182ff24..de88706 100644 (file)
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -107,6 +107,14 @@ static void ocfs2_dentry_post_unlock(struct ocfs2_super *osb,
  * OCFS2 Lock Resource Operations
  *
  * These fine tune the behavior of the generic dlmglue locking infrastructure.
+ *
+ * The most basic of lock types can point ->l_priv to their respective
+ * struct ocfs2_super and allow the default actions to manage things.
+ *
+ * Right now, each lock type also needs to implement an init function,
+ * and trivial lock/unlock wrappers. ocfs2_simple_drop_lockres()
+ * should be called when the lock is no longer needed (i.e., object
+ * destruction time).
  */
 struct ocfs2_lock_res_ops {
        /*
@@ -115,6 +123,15 @@ struct ocfs2_lock_res_ops {
         */
        struct ocfs2_super * (*get_osb)(struct ocfs2_lock_res *);
 
+       /*
+        * Optionally called in the downconvert (or "vote") thread
+        * after a successful downconvert. The lockres will not be
+        * referenced after this callback is called, so it is safe to
+        * free memory, etc.
+        *
+        * The exact semantics of when this is called are controlled
+        * by ->downconvert_worker()
+        */
        void (*post_unlock)(struct ocfs2_super *, struct ocfs2_lock_res *);
 
        /*
@@ -2230,16 +2247,8 @@ complete_unlock:
        mlog_exit_void();
 }
 
-typedef void (ocfs2_pre_drop_cb_t)(struct ocfs2_lock_res *, void *);
-
-struct drop_lock_cb {
-       ocfs2_pre_drop_cb_t     *drop_func;
-       void                    *drop_data;
-};
-
 static int ocfs2_drop_lock(struct ocfs2_super *osb,
-                          struct ocfs2_lock_res *lockres,
-                          struct drop_lock_cb *dcb)
+                          struct ocfs2_lock_res *lockres)
 {
        enum dlm_status status;
        unsigned long flags;
@@ -2274,8 +2283,12 @@ static int ocfs2_drop_lock(struct ocfs2_super *osb,
                spin_lock_irqsave(&lockres->l_lock, flags);
        }
 
-       if (dcb)
-               dcb->drop_func(lockres, dcb->drop_data);
+       if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
+               if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
+                   lockres->l_level == LKM_EXMODE &&
+                   !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
+                       lockres->l_ops->set_lvb(lockres);
+       }
 
        if (lockres->l_flags & OCFS2_LOCK_BUSY)
                mlog(ML_ERROR, "destroying busy lock: \"%s\"\n",
@@ -2355,7 +2368,7 @@ void ocfs2_simple_drop_lockres(struct ocfs2_super *osb,
        int ret;
 
        ocfs2_mark_lockres_freeing(lockres);
-       ret = ocfs2_drop_lock(osb, lockres, NULL);
+       ret = ocfs2_drop_lock(osb, lockres);
        if (ret)
                mlog_errno(ret);
 }
@@ -2366,22 +2379,9 @@ static void ocfs2_drop_osb_locks(struct ocfs2_super *osb)
        ocfs2_simple_drop_lockres(osb, &osb->osb_rename_lockres);
 }
 
-static void ocfs2_meta_pre_drop(struct ocfs2_lock_res *lockres, void *data)
-{
-       struct inode *inode = data;
-
-       /* the metadata lock requires a bit more work as we have an
-        * LVB to worry about. */
-       if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
-           lockres->l_level == LKM_EXMODE &&
-           !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
-               __ocfs2_stuff_meta_lvb(inode);
-}
-
 int ocfs2_drop_inode_locks(struct inode *inode)
 {
        int status, err;
-       struct drop_lock_cb meta_dcb = { ocfs2_meta_pre_drop, inode, };
 
        mlog_entry_void();
 
@@ -2389,24 +2389,21 @@ int ocfs2_drop_inode_locks(struct inode *inode)
         * ocfs2_clear_inode has done it for us. */
 
        err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
-                             &OCFS2_I(inode)->ip_data_lockres,
-                             NULL);
+                             &OCFS2_I(inode)->ip_data_lockres);
        if (err < 0)
                mlog_errno(err);
 
        status = err;
 
        err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
-                             &OCFS2_I(inode)->ip_meta_lockres,
-                             &meta_dcb);
+                             &OCFS2_I(inode)->ip_meta_lockres);
        if (err < 0)
                mlog_errno(err);
        if (err < 0 && !status)
                status = err;
 
        err = ocfs2_drop_lock(OCFS2_SB(inode->i_sb),
-                             &OCFS2_I(inode)->ip_rw_lockres,
-                             NULL);
+                             &OCFS2_I(inode)->ip_rw_lockres);
        if (err < 0)
                mlog_errno(err);
        if (err < 0 && !status)