From 16d5b9567ad5241b5c6e0cc4778c1af6c04bb801 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Wed, 13 Sep 2006 21:10:12 -0700 Subject: ocfs2: Add ->check_downconvert callback in dlmglue This will allow lock types to force a requeue of a lock downconvert. Signed-off-by: Mark Fasheh --- fs/ocfs2/dlmglue.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-) (limited to 'fs/ocfs2') diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c index ebc4a49801bd..9e8ed607173b 100644 --- a/fs/ocfs2/dlmglue.c +++ b/fs/ocfs2/dlmglue.c @@ -118,6 +118,18 @@ struct ocfs2_lock_res_ops { int (*unblock)(struct ocfs2_lock_res *, struct ocfs2_unblock_ctl *); void (*post_unlock)(struct ocfs2_super *, struct ocfs2_lock_res *); + /* + * Allow a lock type to add checks to determine whether it is + * safe to downconvert a lock. Return 0 to re-queue the + * downconvert at a later time, nonzero to continue. + * + * For most locks, the default checks that there are no + * incompatible holders are sufficient. + * + * Called with the lockres spinlock held. + */ + int (*check_downconvert)(struct ocfs2_lock_res *, int); + /* * LOCK_TYPE_* flags which describe the specific requirements * of a lock type. Descriptions of each individual flag follow. @@ -2657,6 +2669,12 @@ recheck: && (lockres->l_flags & OCFS2_LOCK_REFRESHING)) goto leave_requeue; + new_level = ocfs2_highest_compat_lock_level(lockres->l_blocking); + + if (lockres->l_ops->check_downconvert + && !lockres->l_ops->check_downconvert(lockres, new_level)) + goto leave_requeue; + /* If we get here, then we know that there are no more * incompatible holders (and anyone asking for an incompatible * lock is blocked). We can now downconvert the lock */ @@ -2684,7 +2702,6 @@ recheck: downconvert: ctl->requeue = 0; - new_level = ocfs2_highest_compat_lock_level(lockres->l_blocking); ocfs2_prepare_downconvert(lockres, new_level); spin_unlock_irqrestore(&lockres->l_lock, flags); -- cgit v1.2.3