Add tracepoint to catch potential cases where a pending operation overlapping a
reconnect could fail and incorrectly refund its credits causing the client
to think it has more credits available than the server thinks it does.
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/cifs/smb2ops.c | 6 ++++++
fs/cifs/trace.h | 30 ++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 23118b7a2bbc..61ecf7eb8842 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -74,6 +74,12 @@ smb2_add_credits(struct TCP_Server_Info *server,
const unsigned int add,
int *val, rc = 0;
spin_lock(&server->req_lock);
val = server->ops->get_credits_field(server, optype);
+
+ /* eg found case where write overlapping reconnect messed up credits */
+ if (((optype & CIFS_OP_MASK) == CIFS_NEG_OP) && (*val != 0))
+ trace_smb3_reconnect_with_invalid_credits(server->CurrentMid,
+ server->hostname, *val);
+
*val += add;
if (*val > 65000) {
*val = 65000; /* Don't get near 64K credits, avoid srv bugs */
diff --git a/fs/cifs/trace.h b/fs/cifs/trace.h
index d4aed5217a56..43e5bd417b81 100644
--- a/fs/cifs/trace.h
+++ b/fs/cifs/trace.h
@@ -486,6 +486,36 @@ DEFINE_EVENT(smb3_reconnect_class, smb3_##name, \
DEFINE_SMB3_RECONNECT_EVENT(reconnect);
DEFINE_SMB3_RECONNECT_EVENT(partial_send_reconnect);
+DECLARE_EVENT_CLASS(smb3_credit_class,
+ TP_PROTO(__u64 currmid,
+ char *hostname,
+ int credits),
+ TP_ARGS(currmid, hostname, credits),
+ TP_STRUCT__entry(
+ __field(__u64, currmid)
+ __field(char *, hostname)
+ __field(int, credits)
+ ),
+ TP_fast_assign(
+ __entry->currmid = currmid;
+ __entry->hostname = hostname;
+ __entry->credits = credits;
+ ),
+ TP_printk("server=%s current_mid=0x%llx credits=%d",
+ __entry->hostname,
+ __entry->currmid,
+ __entry->credits)
+)
+
+#define DEFINE_SMB3_CREDIT_EVENT(name) \
+DEFINE_EVENT(smb3_credit_class, smb3_##name, \
+ TP_PROTO(__u64 currmid, \
+ char *hostname, \
+ int credits), \
+ TP_ARGS(currmid, hostname, credits))
+
+DEFINE_SMB3_CREDIT_EVENT(reconnect_with_invalid_credits);
+
#endif /* _CIFS_TRACE_H */
#undef TRACE_INCLUDE_PATH
--
2.17.1
--
Thanks,
Steve
From 971b5a5926d52186b7428b6f4ae2a0f6794552e2 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Sat, 1 Sep 2018 01:10:17 -0500
Subject: [PATCH] smb3: add tracepoint to catch cases where credit refund of
failed op overlaps reconnect
Add tracepoint to catch potential cases where a pending operation overlapping a
reconnect could fail and incorrectly refund its credits causing the client
to think it has more credits available than the server thinks it does.
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
---
fs/cifs/smb2ops.c | 6 ++++++
fs/cifs/trace.h | 30 ++++++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 23118b7a2bbc..61ecf7eb8842 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -74,6 +74,12 @@ smb2_add_credits(struct TCP_Server_Info *server, const unsigned int add,
int *val, rc = 0;
spin_lock(&server->req_lock);
val = server->ops->get_credits_field(server, optype);
+
+ /* eg found case where write overlapping reconnect messed up credits */
+ if (((optype & CIFS_OP_MASK) == CIFS_NEG_OP) && (*val != 0))
+ trace_smb3_reconnect_with_invalid_credits(server->CurrentMid,
+ server->hostname, *val);
+
*val += add;
if (*val > 65000) {
*val = 65000; /* Don't get near 64K credits, avoid srv bugs */
diff --git a/fs/cifs/trace.h b/fs/cifs/trace.h
index d4aed5217a56..43e5bd417b81 100644
--- a/fs/cifs/trace.h
+++ b/fs/cifs/trace.h
@@ -486,6 +486,36 @@ DEFINE_EVENT(smb3_reconnect_class, smb3_##name, \
DEFINE_SMB3_RECONNECT_EVENT(reconnect);
DEFINE_SMB3_RECONNECT_EVENT(partial_send_reconnect);
+DECLARE_EVENT_CLASS(smb3_credit_class,
+ TP_PROTO(__u64 currmid,
+ char *hostname,
+ int credits),
+ TP_ARGS(currmid, hostname, credits),
+ TP_STRUCT__entry(
+ __field(__u64, currmid)
+ __field(char *, hostname)
+ __field(int, credits)
+ ),
+ TP_fast_assign(
+ __entry->currmid = currmid;
+ __entry->hostname = hostname;
+ __entry->credits = credits;
+ ),
+ TP_printk("server=%s current_mid=0x%llx credits=%d",
+ __entry->hostname,
+ __entry->currmid,
+ __entry->credits)
+)
+
+#define DEFINE_SMB3_CREDIT_EVENT(name) \
+DEFINE_EVENT(smb3_credit_class, smb3_##name, \
+ TP_PROTO(__u64 currmid, \
+ char *hostname, \
+ int credits), \
+ TP_ARGS(currmid, hostname, credits))
+
+DEFINE_SMB3_CREDIT_EVENT(reconnect_with_invalid_credits);
+
#endif /* _CIFS_TRACE_H */
#undef TRACE_INCLUDE_PATH
--
2.17.1
