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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@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
This commit is contained in:
Steve French 2018-09-01 01:10:17 -05:00
parent ce7fb50f92
commit b340a4d4aa
2 changed files with 36 additions and 0 deletions
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6
fs/cifs/smb2ops.c
View File

@ -74,6 +74,12 @@ smb2_add_credits(struct TCP_Server_Info *server, const unsigned int add,
int *val, rc = 0; int *val, rc = 0;
spin_lock(&server->req_lock); spin_lock(&server->req_lock);
val = server->ops->get_credits_field(server, optype); 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; *val += add;
if (*val > 65000) { if (*val > 65000) {
*val = 65000; /* Don't get near 64K credits, avoid srv bugs */ *val = 65000; /* Don't get near 64K credits, avoid srv bugs */

30
fs/cifs/trace.h
View File

@ -486,6 +486,36 @@ DEFINE_EVENT(smb3_reconnect_class, smb3_##name, \
DEFINE_SMB3_RECONNECT_EVENT(reconnect); DEFINE_SMB3_RECONNECT_EVENT(reconnect);
DEFINE_SMB3_RECONNECT_EVENT(partial_send_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 */ #endif /* _CIFS_TRACE_H */
#undef TRACE_INCLUDE_PATH #undef TRACE_INCLUDE_PATH