[PATCH 1/2] ocfs2: Clean up locking protocol negotiation.

From: Joel Becker
Date: Fri Feb 15 2008 - 21:10:08 EST


The comparison functions for protocol negotiation (introduced in commit
d24fbcda0c4988322949df3d759f1cfb32b32953) were confusing.
Separate out the comparison and value update parts.

Signed-off-by: Joel Becker <joel.becker@xxxxxxxxxx>
---
fs/ocfs2/dlm/dlmdomain.c | 102 ++++++++++++++++++++++------------------------
1 files changed, 49 insertions(+), 53 deletions(-)

diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index 638d2eb..de802a7 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -144,8 +144,6 @@ static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data);
static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
void **ret_data);
-static int dlm_protocol_compare(struct dlm_protocol_version *existing,
- struct dlm_protocol_version *request);

static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);

@@ -681,36 +679,48 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm)
}
EXPORT_SYMBOL_GPL(dlm_unregister_domain);

+/*
+ * Compare a requested locking protocol version against the current one.
+ *
+ * If the major numbers are different, they are incompatible.
+ * If the current minor is greater than the request, they are incompatible.
+ * If the current minor is less than or equal to the request, they are
+ * compatible, and the requester should run at the current minor version.
+ */
+static int dlm_protocol_compatible(struct dlm_protocol_version *existing,
+ struct dlm_protocol_version *request)
+{
+ if (existing->pv_major != request->pv_major)
+ return 0;
+
+ if (existing->pv_minor > request->pv_minor)
+ return 0;
+
+ return 1;
+}
+
static int dlm_query_join_proto_check(char *proto_type, int node,
struct dlm_protocol_version *ours,
struct dlm_protocol_version *request)
{
- int rc;
- struct dlm_protocol_version proto = *request;
+ int compatible = dlm_protocol_compatible(ours, request);

- if (!dlm_protocol_compare(ours, &proto)) {
+ if (compatible)
mlog(0,
"node %u wanted to join with %s locking protocol "
"%u.%u, we respond with %u.%u\n",
node, proto_type,
- request->pv_major,
- request->pv_minor,
- proto.pv_major, proto.pv_minor);
- request->pv_minor = proto.pv_minor;
- rc = 0;
- } else {
+ request->pv_major, request->pv_minor,
+ ours->pv_major, ours->pv_minor);
+ else
mlog(ML_NOTICE,
"Node %u wanted to join with %s locking "
"protocol %u.%u, but we have %u.%u, disallowing\n",
node, proto_type,
- request->pv_major,
- request->pv_minor,
- ours->pv_major,
- ours->pv_minor);
- rc = 1;
- }
+ request->pv_major, request->pv_minor,
+ ours->pv_major, ours->pv_minor);

- return rc;
+ return compatible;
}

static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
@@ -806,21 +816,23 @@ static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
/* Make sure we speak compatible locking protocols. */
if (dlm_query_join_proto_check("DLM", bit,
&dlm->dlm_locking_proto,
- &query->dlm_proto)) {
- response.packet.code =
- JOIN_PROTOCOL_MISMATCH;
- } else if (dlm_query_join_proto_check("fs", bit,
- &dlm->fs_locking_proto,
- &query->fs_proto)) {
- response.packet.code =
- JOIN_PROTOCOL_MISMATCH;
- } else {
+ &query->dlm_proto) &&
+ dlm_query_join_proto_check("fs", bit,
+ &dlm->fs_locking_proto,
+ &query->fs_proto)) {
+ /*
+ * We're compatible, return our
+ * minor number
+ */
response.packet.dlm_minor =
- query->dlm_proto.pv_minor;
+ dlm->dlm_locking_proto.pv_minor;
response.packet.fs_minor =
- query->fs_proto.pv_minor;
+ dlm->fs_locking_proto.pv_minor;
response.packet.code = JOIN_OK;
__dlm_set_joining_node(dlm, query->node_idx);
+ } else {
+ response.packet.code =
+ JOIN_PROTOCOL_MISMATCH;
}
}

@@ -1546,29 +1558,6 @@ leave:
}

/*
- * Compare a requested locking protocol version against the current one.
- *
- * If the major numbers are different, they are incompatible.
- * If the current minor is greater than the request, they are incompatible.
- * If the current minor is less than or equal to the request, they are
- * compatible, and the requester should run at the current minor version.
- */
-static int dlm_protocol_compare(struct dlm_protocol_version *existing,
- struct dlm_protocol_version *request)
-{
- if (existing->pv_major != request->pv_major)
- return 1;
-
- if (existing->pv_minor > request->pv_minor)
- return 1;
-
- if (existing->pv_minor < request->pv_minor)
- request->pv_minor = existing->pv_minor;
-
- return 0;
-}
-
-/*
* dlm_register_domain: one-time setup per "domain".
*
* The filesystem passes in the requested locking version via proto.
@@ -1620,7 +1609,14 @@ retry:
goto retry;
}

- if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
+ if (dlm_protocol_compatible(&dlm->fs_locking_proto, fs_proto)) {
+ /*
+ * We're compatible, and we run at the minor
+ * number negotiated
+ */
+ fs_proto->pv_minor =
+ dlm->fs_locking_proto.pv_minor;
+ } else {
mlog(ML_ERROR,
"Requested locking protocol version is not "
"compatible with already registered domain "
--
1.5.3.8

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