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authorMark Fasheh <mark.fasheh@oracle.com>2006-09-22 17:28:19 -0700
committerMark Fasheh <mark.fasheh@oracle.com>2006-09-24 13:50:46 -0700
commit24c19ef40474c3930597f31ae233dc06319bd881 (patch)
treee05b1cf72435d25bf47e67b206aa376bbea33b7d /fs/ocfs2/cluster
parentf9e2d82e6395cfa0802446b54b63cc412089d82c (diff)
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>
Diffstat (limited to 'fs/ocfs2/cluster')
-rw-r--r--fs/ocfs2/cluster/tcp_internal.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/ocfs2/cluster/tcp_internal.h b/fs/ocfs2/cluster/tcp_internal.h
index da42b515cd1..4b46aac7d24 100644
--- a/fs/ocfs2/cluster/tcp_internal.h
+++ b/fs/ocfs2/cluster/tcp_internal.h
@@ -44,6 +44,9 @@
* locking semantics of the file system using the protocol. It should
* be somewhere else, I'm sure, but right now it isn't.
*
+ * New in version 4:
+ * - Remove i_generation from lock names for better stat performance.
+ *
* New in version 3:
* - Replace dentry votes with a cluster lock
*
@@ -51,7 +54,7 @@
* - full 64 bit i_size in the metadata lock lvbs
* - introduction of "rw" lock and pushing meta/data locking down
*/
-#define O2NET_PROTOCOL_VERSION 3ULL
+#define O2NET_PROTOCOL_VERSION 4ULL
struct o2net_handshake {
__be64 protocol_version;
__be64 connector_id;