From ac391ce3aa27602c81890e8b7e74bff74eb36e50 Mon Sep 17 00:00:00 2001
From: deen <deen>
Date: Fri, 12 Sep 2008 15:46:21 +0000
Subject: [PATCH] Initialize RPC XID from clock at startup (randomly if clock
is bad).
b=2066
i=adilger
i=robert.read
---
lustre/ChangeLog | 6 +++++
lustre/ptlrpc/client.c | 39 +++++++++++++++++++++++++++++++--
lustre/ptlrpc/ptlrpc_internal.h | 7 ++++++
lustre/ptlrpc/ptlrpc_module.c | 4 +---
4 files changed, 51 insertions(+), 5 deletions(-)
diff --git a/lustre/ChangeLog b/lustre/ChangeLog
index f9ebc36882..4141ff900c 100644
--- a/lustre/ChangeLog
+++ b/lustre/ChangeLog
@@ -1401,6 +1401,12 @@ Bugzilla : 16813
Description: X2 build failures
Details : fix build failures on Cray X2.
+Severity : normal
+Bugzilla : 2066
+Description: xid & resent requests
+Details : Initialize RPC XID from clock at startup (randomly if clock is
+ bad).
+
--------------------------------------------------------------------------------
2007-08-10 Cluster File Systems, Inc. <info@clusterfs.com>
diff --git a/lustre/ptlrpc/client.c b/lustre/ptlrpc/client.c
index 7ce2ef5583..cbe80c696e 100644
--- a/lustre/ptlrpc/client.c
+++ b/lustre/ptlrpc/client.c
@@ -2350,8 +2350,37 @@ void ptlrpc_abort_set(struct ptlrpc_request_set *set)
}
}
-static __u64 ptlrpc_last_xid = 0;
-spinlock_t ptlrpc_last_xid_lock;
+static __u64 ptlrpc_last_xid;
+static spinlock_t ptlrpc_last_xid_lock;
+
+/* Initialize the XID for the node. This is common among all requests on
+ * this node, and only requires the property that it is monotonically
+ * increasing. It does not need to be sequential. Since this is also used
+ * as the RDMA match bits, it is important that a single client NOT have
+ * the same match bits for two different in-flight requests, hence we do
+ * NOT want to have an XID per target or similar.
+ *
+ * To avoid an unlikely collision between match bits after a client reboot
+ * (which would cause old to be delivered into the wrong buffer) we initialize
+ * the XID based on the current time, assuming a maximum RPC rate of 1M RPC/s.
+ * If the time is clearly incorrect, we instead use a 62-bit random number.
+ * In the worst case the random number will overflow 1M RPCs per second in
+ * 9133 years, or permutations thereof.
+ */
+#define YEAR_2004 (1ULL << 30)
+void ptlrpc_init_xid(void)
+{
+ time_t now = cfs_time_current_sec();
+
+ spin_lock_init(&ptlrpc_last_xid_lock);
+ if (now < YEAR_2004) {
+ ll_get_random_bytes(&ptlrpc_last_xid, sizeof(ptlrpc_last_xid));
+ ptlrpc_last_xid >>= 2;
+ ptlrpc_last_xid |= (1ULL << 61);
+ } else {
+ ptlrpc_last_xid = (now << 20);
+ }
+}
__u64 ptlrpc_next_xid(void)
{
@@ -2364,10 +2393,16 @@ __u64 ptlrpc_next_xid(void)
__u64 ptlrpc_sample_next_xid(void)
{
+#if BITS_PER_LONG == 32
+ /* need to avoid possible word tearing on 32-bit systems */
__u64 tmp;
spin_lock(&ptlrpc_last_xid_lock);
tmp = ptlrpc_last_xid + 1;
spin_unlock(&ptlrpc_last_xid_lock);
return tmp;
+#else
+ /* No need to lock, since returned value is racy anyways */
+ return ptlrpc_last_xid + 1;
+#endif
}
EXPORT_SYMBOL(ptlrpc_sample_next_xid);
diff --git a/lustre/ptlrpc/ptlrpc_internal.h b/lustre/ptlrpc/ptlrpc_internal.h
index 4ebb4482ac..bdea8bd672 100644
--- a/lustre/ptlrpc/ptlrpc_internal.h
+++ b/lustre/ptlrpc/ptlrpc_internal.h
@@ -47,6 +47,13 @@ struct ldlm_res_id;
struct ptlrpc_request_set;
extern int test_req_buffer_pressure;
+/* client.c */
+void ptlrpc_init_xid(void);
+
+/* events.c */
+int ptlrpc_init_portals(void);
+void ptlrpc_exit_portals(void);
+
void ptlrpc_request_handle_notconn(struct ptlrpc_request *);
void lustre_assert_wire_constants(void);
int ptlrpc_import_in_recovery(struct obd_import *imp);
diff --git a/lustre/ptlrpc/ptlrpc_module.c b/lustre/ptlrpc/ptlrpc_module.c
index 6bb04f9579..5d7d35eb5f 100644
--- a/lustre/ptlrpc/ptlrpc_module.c
+++ b/lustre/ptlrpc/ptlrpc_module.c
@@ -55,8 +55,6 @@ extern spinlock_t ptlrpc_rs_debug_lock;
extern spinlock_t ptlrpc_all_services_lock;
extern struct semaphore pinger_sem;
extern struct semaphore ptlrpcd_sem;
-extern int ptlrpc_init_portals(void);
-extern void ptlrpc_exit_portals(void);
__init int ptlrpc_init(void)
{
@@ -64,11 +62,11 @@ __init int ptlrpc_init(void)
ENTRY;
lustre_assert_wire_constants();
- spin_lock_init(&ptlrpc_last_xid_lock);
spin_lock_init(&ptlrpc_rs_debug_lock);
spin_lock_init(&ptlrpc_all_services_lock);
init_mutex(&pinger_sem);
init_mutex(&ptlrpcd_sem);
+ ptlrpc_init_xid();
rc = req_layout_init();
if (rc)
--
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