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, 2 insertions, 1 deletions

diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index f92bf1dd379..fd9734def55 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -1493,7 +1493,8 @@ static int ocfs2_queue_orphans(struct ocfs2_super *osb,
 			if (de->name_len == 2 && !strncmp("..", de->name, 2))
 				continue;
 
-			iter = ocfs2_iget(osb, le64_to_cpu(de->inode));
+			iter = ocfs2_iget(osb, le64_to_cpu(de->inode),
+					  OCFS2_FI_FLAG_NOLOCK);
 			if (IS_ERR(iter))
 				continue;