[Ocfs2-devel] [PATCH] ocfs2: Do not lock/unlock() inode DLM lock

[rgoldwyn at suse.de]

From: Goldwyn Rodrigues <rgoldwyn at suse.com>

DLM does not cache locks. So, blocking lock and unlock
will only make the performance worse where contention over
the locks is high.

Signed-off-by: Goldwyn Rodrigues <rgoldwyn at suse.com>
---
 fs/ocfs2/dlmglue.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 20276e3..f92612e 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -2432,12 +2432,6 @@ bail:
  * done this we have to return AOP_TRUNCATED_PAGE so the aop method
  * that called us can bubble that back up into the VFS who will then
  * immediately retry the aop call.
- *
- * We do a blocking lock and immediate unlock before returning, though, so that
- * the lock has a great chance of being cached on this node by the time the VFS
- * calls back to retry the aop.    This has a potential to livelock as nodes
- * ping locks back and forth, but that's a risk we're willing to take to avoid
- * the lock inversion simply.
  */
 int ocfs2_inode_lock_with_page(struct inode *inode,
 			      struct buffer_head **ret_bh,
@@ -2449,8 +2443,6 @@ int ocfs2_inode_lock_with_page(struct inode *inode,
 	ret = ocfs2_inode_lock_full(inode, ret_bh, ex, OCFS2_LOCK_NONBLOCK);
 	if (ret == -EAGAIN) {
 		unlock_page(page);
-		if (ocfs2_inode_lock(inode, ret_bh, ex) == 0)
-			ocfs2_inode_unlock(inode, ex);
 		ret = AOP_TRUNCATED_PAGE;
 	}
 
-- 
2.6.2