Commit 6d82c27a authored by Shyam Prasad N's avatar Shyam Prasad N Committed by Steve French
Browse files

cifs: Identify a connection by a conn_id. 



Introduced a new field conn_id in TCP_Server_Info structure.
This is a non-persistent unique identifier maintained by the client
for a connection to a file server. For this, a global counter named
tcpSesNextId is maintained. On allocating a new TCP_Server_Info,
this counter is incremented and assigned.

Changed the dynamic tracepoints related to reconnects and
crediting to be more informative (with conn_id printed).
Debugging a crediting issue helped me understand the
important things to print here.

Always call dynamic tracepoints outside the scope of spinlocks.
To do this, copy out the credits and in_flight fields of the
server struct before dropping the lock.

Signed-off-by: default avatarShyam Prasad N <sprasad@microsoft.com>
Reviewed-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 7de03948

fs/cifs/cifsfs.c

+1 −0
Original line number Diff line number Diff line
@@ -1525,6 +1525,7 @@ init_cifs(void) 
 */

	atomic_set(&sesInfoAllocCount, 0);

	atomic_set(&tconInfoAllocCount, 0);

	atomic_set(&tcpSesNextId, 0);

	atomic_set(&tcpSesAllocCount, 0);

	atomic_set(&tcpSesReconnectCount, 0);

	atomic_set(&tconInfoReconnectCount, 0);

fs/cifs/cifsglob.h

+2 −0
Original line number Diff line number Diff line
@@ -577,6 +577,7 @@ inc_rfc1001_len(void *buf, int count) 
struct TCP_Server_Info {

	struct list_head tcp_ses_list;

	struct list_head smb_ses_list;

	__u64 conn_id; /* connection identifier (useful for debugging) */

	int srv_count; /* reference counter */

	/* 15 character server name + 0x20 16th byte indicating type = srv */

	char server_RFC1001_name[RFC1001_NAME_LEN_WITH_NULL];
@@ -1846,6 +1847,7 @@ GLOBAL_EXTERN spinlock_t GlobalMid_Lock; /* protects above & list operations */ 
 */

GLOBAL_EXTERN atomic_t sesInfoAllocCount;

GLOBAL_EXTERN atomic_t tconInfoAllocCount;

GLOBAL_EXTERN atomic_t tcpSesNextId;

GLOBAL_EXTERN atomic_t tcpSesAllocCount;

GLOBAL_EXTERN atomic_t tcpSesReconnectCount;

GLOBAL_EXTERN atomic_t tconInfoReconnectCount;

fs/cifs/connect.c

+7 −4
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ cifs_reconnect(struct TCP_Server_Info *server) 
	server->max_read = 0;



	cifs_dbg(FYI, "Mark tcp session as need reconnect\n");

	trace_smb3_reconnect(server->CurrentMid, server->hostname);

	trace_smb3_reconnect(server->CurrentMid, server->conn_id, server->hostname);



	/* before reconnecting the tcp session, mark the smb session (uid)

		and the tid bad so they are not used until reconnected */
@@ -846,7 +846,7 @@ static void 
smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server)

{

	struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buffer;

	int scredits = server->credits;

	int scredits, in_flight;



	/*

	 * SMB1 does not use credits.
@@ -857,12 +857,14 @@ smb2_add_credits_from_hdr(char *buffer, struct TCP_Server_Info *server) 
	if (shdr->CreditRequest) {

		spin_lock(&server->req_lock);

		server->credits += le16_to_cpu(shdr->CreditRequest);

		scredits = server->credits;

		in_flight = server->in_flight;

		spin_unlock(&server->req_lock);

		wake_up(&server->request_q);



		trace_smb3_add_credits(server->CurrentMid,

				server->hostname, scredits,

				le16_to_cpu(shdr->CreditRequest));

				server->conn_id, server->hostname, scredits,

				le16_to_cpu(shdr->CreditRequest), in_flight);

		cifs_server_dbg(FYI, "%s: added %u credits total=%d\n",

				__func__, le16_to_cpu(shdr->CreditRequest),

				scredits);
@@ -1317,6 +1319,7 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx) 
		goto out_err_crypto_release;

	}



	tcp_ses->conn_id = atomic_inc_return(&tcpSesNextId);

	tcp_ses->noblockcnt = ctx->rootfs;

	tcp_ses->noblocksnd = ctx->noblocksnd || ctx->rootfs;

	tcp_ses->noautotune = ctx->noautotune;

fs/cifs/smb2ops.c

+47 −16
Original line number Diff line number Diff line
@@ -63,17 +63,19 @@ smb2_add_credits(struct TCP_Server_Info *server, 
		 const struct cifs_credits *credits, const int optype)

{

	int *val, rc = -1;

	int scredits, in_flight;

	unsigned int add = credits->value;

	unsigned int instance = credits->instance;

	bool reconnect_detected = false;

	bool reconnect_with_invalid_credits = false;



	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, add);

		reconnect_with_invalid_credits = true;



	if ((instance == 0) || (instance == server->reconnect_instance))

		*val += add;

	else
@@ -99,14 +101,26 @@ smb2_add_credits(struct TCP_Server_Info *server, 
			server->oplock_credits++;

		}

	}

	scredits = *val;

	in_flight = server->in_flight;

	spin_unlock(&server->req_lock);

	wake_up(&server->request_q);



	if (reconnect_detected) {

		trace_smb3_reconnect_detected(server->CurrentMid,

			server->conn_id, server->hostname, scredits, add, in_flight);



		cifs_dbg(FYI, "trying to put %d credits from the old server instance %d\n",

			 add, instance);

	}



	if (reconnect_with_invalid_credits) {

		trace_smb3_reconnect_with_invalid_credits(server->CurrentMid,

			server->conn_id, server->hostname, scredits, add, in_flight);

		cifs_dbg(FYI, "Negotiate operation when server credits is non-zero. Optype: %d, server credits: %d, credits added: %d\n",

			 optype, scredits, add);

	}



	if (server->tcpStatus == CifsNeedReconnect

	    || server->tcpStatus == CifsExiting)

		return;
@@ -125,23 +139,30 @@ smb2_add_credits(struct TCP_Server_Info *server, 
		cifs_dbg(FYI, "disabling oplocks\n");

		break;

	default:

		trace_smb3_add_credits(server->CurrentMid,

			server->hostname, rc, add);

		cifs_dbg(FYI, "%s: added %u credits total=%d\n", __func__, add, rc);

		/* change_conf rebalanced credits for different types */

		break;

	}



	trace_smb3_add_credits(server->CurrentMid,

			server->conn_id, server->hostname, scredits, add, in_flight);

	cifs_dbg(FYI, "%s: added %u credits total=%d\n", __func__, add, scredits);

}



static void

smb2_set_credits(struct TCP_Server_Info *server, const int val)

{

	int scredits, in_flight;



	spin_lock(&server->req_lock);

	server->credits = val;

	if (val == 1)

		server->reconnect_instance++;

	scredits = server->credits;

	in_flight = server->in_flight;

	spin_unlock(&server->req_lock);



	trace_smb3_set_credits(server->CurrentMid,

			server->hostname, val, val);

			server->conn_id, server->hostname, scredits, val, in_flight);

	cifs_dbg(FYI, "%s: set %u credits\n", __func__, val);



	/* don't log while holding the lock */
@@ -173,7 +194,7 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size, 
		      unsigned int *num, struct cifs_credits *credits)

{

	int rc = 0;

	unsigned int scredits;

	unsigned int scredits, in_flight;



	spin_lock(&server->req_lock);

	while (1) {
@@ -210,17 +231,18 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size, 
				DIV_ROUND_UP(*num, SMB2_MAX_BUFFER_SIZE);

			credits->instance = server->reconnect_instance;

			server->credits -= credits->value;

			scredits = server->credits;

			server->in_flight++;

			if (server->in_flight > server->max_in_flight)

				server->max_in_flight = server->in_flight;

			break;

		}

	}

	scredits = server->credits;

	in_flight = server->in_flight;

	spin_unlock(&server->req_lock);



	trace_smb3_add_credits(server->CurrentMid,

			server->hostname, scredits, -(credits->value));

			server->conn_id, server->hostname, scredits, -(credits->value), in_flight);

	cifs_dbg(FYI, "%s: removed %u credits total=%d\n",

			__func__, credits->value, scredits);
@@ -233,14 +255,14 @@ smb2_adjust_credits(struct TCP_Server_Info *server, 
		    const unsigned int payload_size)

{

	int new_val = DIV_ROUND_UP(payload_size, SMB2_MAX_BUFFER_SIZE);

	int scredits;

	int scredits, in_flight;



	if (!credits->value || credits->value == new_val)

		return 0;



	if (credits->value < new_val) {

		trace_smb3_too_many_credits(server->CurrentMid,

				server->hostname, 0, credits->value - new_val);

				server->conn_id, server->hostname, 0, credits->value - new_val, 0);

		cifs_server_dbg(VFS, "request has less credits (%d) than required (%d)",

				credits->value, new_val);
@@ -250,9 +272,13 @@ smb2_adjust_credits(struct TCP_Server_Info *server, 
	spin_lock(&server->req_lock);



	if (server->reconnect_instance != credits->instance) {

		scredits = server->credits;

		in_flight = server->in_flight;

		spin_unlock(&server->req_lock);



		trace_smb3_reconnect_detected(server->CurrentMid,

			server->hostname, 0, 0);

			server->conn_id, server->hostname, scredits,

			credits->value - new_val, in_flight);

		cifs_server_dbg(VFS, "trying to return %d credits to old session\n",

			 credits->value - new_val);

		return -EAGAIN;
@@ -260,15 +286,18 @@ smb2_adjust_credits(struct TCP_Server_Info *server, 


	server->credits += credits->value - new_val;

	scredits = server->credits;

	in_flight = server->in_flight;

	spin_unlock(&server->req_lock);

	wake_up(&server->request_q);

	credits->value = new_val;



	trace_smb3_add_credits(server->CurrentMid,

			server->hostname, scredits, credits->value - new_val);

			server->conn_id, server->hostname, scredits,

			credits->value - new_val, in_flight);

	cifs_dbg(FYI, "%s: adjust added %u credits total=%d\n",

			__func__, credits->value - new_val, scredits);



	credits->value = new_val;



	return 0;

}
@@ -2371,7 +2400,7 @@ static bool 
smb2_is_status_pending(char *buf, struct TCP_Server_Info *server)

{

	struct smb2_sync_hdr *shdr = (struct smb2_sync_hdr *)buf;

	int scredits;

	int scredits, in_flight;



	if (shdr->Status != STATUS_PENDING)

		return false;
@@ -2380,11 +2409,13 @@ smb2_is_status_pending(char *buf, struct TCP_Server_Info *server) 
		spin_lock(&server->req_lock);

		server->credits += le16_to_cpu(shdr->CreditRequest);

		scredits = server->credits;

		in_flight = server->in_flight;

		spin_unlock(&server->req_lock);

		wake_up(&server->request_q);



		trace_smb3_add_credits(server->CurrentMid,

				server->hostname, scredits, le16_to_cpu(shdr->CreditRequest));

				server->conn_id, server->hostname, scredits,

				le16_to_cpu(shdr->CreditRequest), in_flight);

		cifs_dbg(FYI, "%s: status pending add %u credits total=%d\n",

				__func__, le16_to_cpu(shdr->CreditRequest), scredits);

	}

fs/cifs/trace.h

+26 −10
Original line number Diff line number Diff line
@@ -851,17 +851,21 @@ DEFINE_SMB3_LEASE_ERR_EVENT(lease_err); 


DECLARE_EVENT_CLASS(smb3_reconnect_class,

	TP_PROTO(__u64	currmid,

		__u64 conn_id,

		char *hostname),

	TP_ARGS(currmid, hostname),

	TP_ARGS(currmid, conn_id, hostname),

	TP_STRUCT__entry(

		__field(__u64, currmid)

		__field(__u64, conn_id)

		__field(char *, hostname)

	),

	TP_fast_assign(

		__entry->currmid = currmid;

		__entry->conn_id = conn_id;

		__entry->hostname = hostname;

	),

	TP_printk("server=%s current_mid=0x%llx",

	TP_printk("conn_id=0x%llx server=%s current_mid=%llu",

		__entry->conn_id,

		__entry->hostname,

		__entry->currmid)

)
@@ -869,44 +873,56 @@ DECLARE_EVENT_CLASS(smb3_reconnect_class, 
#define DEFINE_SMB3_RECONNECT_EVENT(name)        \

DEFINE_EVENT(smb3_reconnect_class, smb3_##name,  \

	TP_PROTO(__u64	currmid,		\

		__u64 conn_id,			\

		char *hostname),				\

	TP_ARGS(currmid, hostname))

	TP_ARGS(currmid, conn_id, hostname))



DEFINE_SMB3_RECONNECT_EVENT(reconnect);

DEFINE_SMB3_RECONNECT_EVENT(partial_send_reconnect);



DECLARE_EVENT_CLASS(smb3_credit_class,

	TP_PROTO(__u64	currmid,

		__u64 conn_id,

		char *hostname,

		int credits,

		int credits_to_add),

	TP_ARGS(currmid, hostname, credits, credits_to_add),

		int credits_to_add,

		int in_flight),

	TP_ARGS(currmid, conn_id, hostname, credits, credits_to_add, in_flight),

	TP_STRUCT__entry(

		__field(__u64, currmid)

		__field(__u64, conn_id)

		__field(char *, hostname)

		__field(int, credits)

		__field(int, credits_to_add)

		__field(int, in_flight)

	),

	TP_fast_assign(

		__entry->currmid = currmid;

		__entry->conn_id = conn_id;

		__entry->hostname = hostname;

		__entry->credits = credits;

		__entry->credits_to_add = credits_to_add;

		__entry->in_flight = in_flight;

	),

	TP_printk("server=%s current_mid=0x%llx credits=%d credits_to_add=%d",

	TP_printk("conn_id=0x%llx server=%s current_mid=%llu "

			"credits=%d credit_change=%d in_flight=%d",

		__entry->conn_id,

		__entry->hostname,

		__entry->currmid,

		__entry->credits,

		__entry->credits_to_add)

		__entry->credits_to_add,

		__entry->in_flight)

)



#define DEFINE_SMB3_CREDIT_EVENT(name)        \

DEFINE_EVENT(smb3_credit_class, smb3_##name,  \

	TP_PROTO(__u64	currmid,		\

		__u64 conn_id,			\

		char *hostname,			\

		int  credits,			\

		int  credits_to_add),		\

	TP_ARGS(currmid, hostname, credits, credits_to_add))

		int  credits_to_add,	\

		int in_flight),			\

	TP_ARGS(currmid, conn_id, hostname, credits, credits_to_add, in_flight))



DEFINE_SMB3_CREDIT_EVENT(reconnect_with_invalid_credits);

DEFINE_SMB3_CREDIT_EVENT(reconnect_detected);