ocfs2: Add ->set_lvb callback in dlmglue
This allows a lock type to set the value block before downconvert.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 9e8ed60..faa6f57 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -131,6 +131,17 @@
int (*check_downconvert)(struct ocfs2_lock_res *, int);
/*
+ * Allows a lock type to populate the lock value block. This
+ * is called on downconvert, and when we drop a lock.
+ *
+ * Locks that want to use this should set LOCK_TYPE_USES_LVB
+ * in the flags field.
+ *
+ * Called with the lockres spinlock held.
+ */
+ void (*set_lvb)(struct ocfs2_lock_res *);
+
+ /*
* LOCK_TYPE_* flags which describe the specific requirements
* of a lock type. Descriptions of each individual flag follow.
*/
@@ -148,7 +159,8 @@
#define LOCK_TYPE_REQUIRES_REFRESH 0x1
/*
- * Indicate that a lock type makes use of the lock value block.
+ * Indicate that a lock type makes use of the lock value block. The
+ * ->set_lvb lock type callback must be defined.
*/
#define LOCK_TYPE_USES_LVB 0x2
@@ -2629,6 +2641,7 @@
int blocking;
int new_level;
int ret = 0;
+ int set_lvb = 0;
mlog_entry_void();
@@ -2703,9 +2716,23 @@
downconvert:
ctl->requeue = 0;
+ if (lockres->l_ops->flags & LOCK_TYPE_USES_LVB) {
+ if (lockres->l_level == LKM_EXMODE)
+ set_lvb = 1;
+
+ /*
+ * We only set the lvb if the lock has been fully
+ * refreshed - otherwise we risk setting stale
+ * data. Otherwise, there's no need to actually clear
+ * out the lvb here as it's value is still valid.
+ */
+ if (set_lvb && !(lockres->l_flags & OCFS2_LOCK_NEEDS_REFRESH))
+ lockres->l_ops->set_lvb(lockres);
+ }
+
ocfs2_prepare_downconvert(lockres, new_level);
spin_unlock_irqrestore(&lockres->l_lock, flags);
- ret = ocfs2_downconvert_lock(osb, lockres, new_level, 0);
+ ret = ocfs2_downconvert_lock(osb, lockres, new_level, set_lvb);
leave:
mlog_exit(ret);
return ret;
