ocfs2: Remove i_generation from inode lock names

OCFS2 puts inode meta data in the "lock value block" provided by the DLM.
Typically, i_generation is encoded in the lock name so that a deleted inode
on and a new one in the same block don't share the same lvb.

Unfortunately, that scheme means that the read in ocfs2_read_locked_inode()
is potentially thrown away as soon as the meta data lock is taken - we
cannot encode the lock name without first knowing i_generation, which
requires a disk read.

This patch encodes i_generation in the inode meta data lvb, and removes the
value from the inode meta data lock name. This way, the read can be covered
by a lock, and at the same time we can distinguish between an up to date and
a stale LVB.

This will help cold-cache stat(2) performance in particular.

Since this patch changes the protocol version, we take the opportunity to do
a minor re-organization of two of the LVB fields.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 6fa9788..849c3b4 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -179,7 +179,7 @@ static struct dentry *ocfs2_lookup(struct inode *dir, struct dentry *dentry,
 	if (status < 0)
 		goto bail_add;
 
-	inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno);
+	inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0);
 	if (IS_ERR(inode)) {
 		mlog(ML_ERROR, "Unable to create inode %llu\n",
 		     (unsigned long long)blkno);