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, 2 deletions

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 33a6de6fc612..4c29cd7cc8e6 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -202,7 +202,7 @@ static int ocfs2_init_global_system_inodes(struct ocfs2_super *osb)
 
         mlog_entry_void();
 
-        new = ocfs2_iget(osb, osb->root_blkno);
+        new = ocfs2_iget(osb, osb->root_blkno, OCFS2_FI_FLAG_SYSFILE);
         if (IS_ERR(new)) {
                 status = PTR_ERR(new);
                 mlog_errno(status);
@@ -210,7 +210,7 @@ static int ocfs2_init_global_system_inodes(struct ocfs2_super *osb)
         }
         osb->root_inode = new;
 
-        new = ocfs2_iget(osb, osb->system_dir_blkno);
+        new = ocfs2_iget(osb, osb->system_dir_blkno, OCFS2_FI_FLAG_SYSFILE);
         if (IS_ERR(new)) {
                 status = PTR_ERR(new);
                 mlog_errno(status);