Commit 519be989 authored by David Howells's avatar David Howells Committed by Steve French
Browse files

cifs: Add a tracepoint to track credits involved in R/W requests 



Add a tracepoint to track the credit changes and server in_flight value
involved in the lifetime of a R/W request, logging it against the
request/subreq debugging ID.  This requires the debugging IDs to be
recorded in the cifs_credits struct.

The tracepoint can be enabled with:

	echo 1 >/sys/kernel/debug/tracing/events/cifs/smb3_rw_credits/enable

Also add a three-state flag to struct cifs_credits to note if we're
interested in determining when the in_flight contribution ends and, if so,
to track whether we've decremented the contribution yet.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarPaulo Alcantara (Red Hat) <pc@manguebit.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 61ea6b3a

fs/smb/client/cifsglob.h

+10 −7
Original line number Diff line number Diff line
@@ -290,7 +290,7 @@ struct smb_version_operations { 
	int (*check_receive)(struct mid_q_entry *, struct TCP_Server_Info *,

			     bool);

	void (*add_credits)(struct TCP_Server_Info *server,

			    const struct cifs_credits *credits,

			    struct cifs_credits *credits,

			    const int optype);

	void (*set_credits)(struct TCP_Server_Info *, const int);

	int * (*get_credits_field)(struct TCP_Server_Info *, const int);
@@ -550,8 +550,8 @@ struct smb_version_operations { 
				size_t *, struct cifs_credits *);

	/* adjust previously taken mtu credits to request size */

	int (*adjust_credits)(struct TCP_Server_Info *server,

			      struct cifs_credits *credits,

			      const unsigned int payload_size);

			      struct cifs_io_subrequest *subreq,

			      unsigned int /*enum smb3_rw_credits_trace*/ trace);

	/* check if we need to issue closedir */

	bool (*dir_needs_close)(struct cifsFileInfo *);

	long (*fallocate)(struct file *, struct cifs_tcon *, int, loff_t,
@@ -848,6 +848,9 @@ static inline void cifs_server_unlock(struct TCP_Server_Info *server) 
struct cifs_credits {

	unsigned int value;

	unsigned int instance;

	unsigned int in_flight_check;

	unsigned int rreq_debug_id;

	unsigned int rreq_debug_index;

};



static inline unsigned int
@@ -873,7 +876,7 @@ has_credits(struct TCP_Server_Info *server, int *credits, int num_credits) 
}



static inline void

add_credits(struct TCP_Server_Info *server, const struct cifs_credits *credits,

add_credits(struct TCP_Server_Info *server, struct cifs_credits *credits,

	    const int optype)

{

	server->ops->add_credits(server, credits, optype);
@@ -897,11 +900,11 @@ set_credits(struct TCP_Server_Info *server, const int val) 
}



static inline int

adjust_credits(struct TCP_Server_Info *server, struct cifs_credits *credits,

	       const unsigned int payload_size)

adjust_credits(struct TCP_Server_Info *server, struct cifs_io_subrequest *subreq,

	       unsigned int /* enum smb3_rw_credits_trace */ trace)

{

	return server->ops->adjust_credits ?

		server->ops->adjust_credits(server, credits, payload_size) : 0;

		server->ops->adjust_credits(server, subreq, trace) : 0;

}



static inline __le64

fs/smb/client/file.c

+31 −1
Original line number Diff line number Diff line
@@ -80,6 +80,16 @@ static void cifs_prepare_write(struct netfs_io_subrequest *subreq) 
		return netfs_prepare_write_failed(subreq);

	}



	wdata->credits.rreq_debug_id = subreq->rreq->debug_id;

	wdata->credits.rreq_debug_index = subreq->debug_index;

	wdata->credits.in_flight_check = 1;

	trace_smb3_rw_credits(wdata->rreq->debug_id,

			      wdata->subreq.debug_index,

			      wdata->credits.value,

			      server->credits, server->in_flight,

			      wdata->credits.value,

			      cifs_trace_rw_credits_write_prepare);



#ifdef CONFIG_CIFS_SMB_DIRECT

	if (server->smbd_conn)

		subreq->max_nr_segs = server->smbd_conn->max_frmr_depth;
@@ -101,7 +111,7 @@ static void cifs_issue_write(struct netfs_io_subrequest *subreq) 
		goto fail;

	}



	rc = adjust_credits(wdata->server, &wdata->credits, wdata->subreq.len);

	rc = adjust_credits(wdata->server, wdata, cifs_trace_rw_credits_issue_write_adjust);

	if (rc)

		goto fail;
@@ -158,7 +168,18 @@ static bool cifs_clamp_length(struct netfs_io_subrequest *subreq) 
		return false;

	}



	rdata->credits.in_flight_check = 1;

	rdata->credits.rreq_debug_id = rreq->debug_id;

	rdata->credits.rreq_debug_index = subreq->debug_index;



	trace_smb3_rw_credits(rdata->rreq->debug_id,

			      rdata->subreq.debug_index,

			      rdata->credits.value,

			      server->credits, server->in_flight, 0,

			      cifs_trace_rw_credits_read_submit);



	subreq->len = min_t(size_t, subreq->len, rsize);



#ifdef CONFIG_CIFS_SMB_DIRECT

	if (server->smbd_conn)

		subreq->max_nr_segs = server->smbd_conn->max_frmr_depth;
@@ -289,6 +310,15 @@ static void cifs_free_subrequest(struct netfs_io_subrequest *subreq) 
#endif

	}



	if (rdata->credits.value != 0)

		trace_smb3_rw_credits(rdata->rreq->debug_id,

				      rdata->subreq.debug_index,

				      rdata->credits.value,

				      rdata->server ? rdata->server->credits : 0,

				      rdata->server ? rdata->server->in_flight : 0,

				      -rdata->credits.value,

				      cifs_trace_rw_credits_free_subreq);



	add_credits_and_wake_if(rdata->server, &rdata->credits, 0);

	if (rdata->have_xid)

		free_xid(rdata->xid);

fs/smb/client/smb1ops.c

+1 −1
Original line number Diff line number Diff line
@@ -108,7 +108,7 @@ cifs_find_mid(struct TCP_Server_Info *server, char *buffer) 


static void

cifs_add_credits(struct TCP_Server_Info *server,

		 const struct cifs_credits *credits, const int optype)

		 struct cifs_credits *credits, const int optype)

{

	spin_lock(&server->req_lock);

	server->credits += credits->value;

fs/smb/client/smb2ops.c

+37 −5
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ change_conf(struct TCP_Server_Info *server) 


static void

smb2_add_credits(struct TCP_Server_Info *server,

		 const struct cifs_credits *credits, const int optype)

		 struct cifs_credits *credits, const int optype)

{

	int *val, rc = -1;

	int scredits, in_flight;
@@ -94,7 +94,21 @@ smb2_add_credits(struct TCP_Server_Info *server, 
					    server->conn_id, server->hostname, *val,

					    add, server->in_flight);

	}

	WARN_ON_ONCE(server->in_flight == 0);

	if (credits->in_flight_check > 1) {

		pr_warn_once("rreq R=%08x[%x] Credits not in flight\n",

			     credits->rreq_debug_id, credits->rreq_debug_index);

	} else {

		credits->in_flight_check = 2;

	}

	if (WARN_ON_ONCE(server->in_flight == 0)) {

		pr_warn_once("rreq R=%08x[%x] Zero in_flight\n",

			     credits->rreq_debug_id, credits->rreq_debug_index);

		trace_smb3_rw_credits(credits->rreq_debug_id,

				      credits->rreq_debug_index,

				      credits->value,

				      server->credits, server->in_flight, 0,

				      cifs_trace_rw_credits_zero_in_flight);

	}

	server->in_flight--;

	if (server->in_flight == 0 &&

	   ((optype & CIFS_OP_MASK) != CIFS_NEG_OP) &&
@@ -283,16 +297,23 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, size_t size, 


static int

smb2_adjust_credits(struct TCP_Server_Info *server,

		    struct cifs_credits *credits,

		    const unsigned int payload_size)

		    struct cifs_io_subrequest *subreq,

		    unsigned int /*enum smb3_rw_credits_trace*/ trace)

{

	int new_val = DIV_ROUND_UP(payload_size, SMB2_MAX_BUFFER_SIZE);

	struct cifs_credits *credits = &subreq->credits;

	int new_val = DIV_ROUND_UP(subreq->subreq.len, SMB2_MAX_BUFFER_SIZE);

	int scredits, in_flight;



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

		return 0;



	if (credits->value < new_val) {

		trace_smb3_rw_credits(subreq->rreq->debug_id,

				      subreq->subreq.debug_index,

				      credits->value,

				      server->credits, server->in_flight,

				      new_val - credits->value,

				      cifs_trace_rw_credits_no_adjust_up);

		trace_smb3_too_many_credits(server->CurrentMid,

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

		cifs_server_dbg(VFS, "request has less credits (%d) than required (%d)",
@@ -308,6 +329,12 @@ smb2_adjust_credits(struct TCP_Server_Info *server, 
		in_flight = server->in_flight;

		spin_unlock(&server->req_lock);



		trace_smb3_rw_credits(subreq->rreq->debug_id,

				      subreq->subreq.debug_index,

				      credits->value,

				      server->credits, server->in_flight,

				      new_val - credits->value,

				      cifs_trace_rw_credits_old_session);

		trace_smb3_reconnect_detected(server->CurrentMid,

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

			credits->value - new_val, in_flight);
@@ -316,6 +343,11 @@ smb2_adjust_credits(struct TCP_Server_Info *server, 
		return -EAGAIN;

	}



	trace_smb3_rw_credits(subreq->rreq->debug_id,

			      subreq->subreq.debug_index,

			      credits->value,

			      server->credits, server->in_flight,

			      new_val - credits->value, trace);

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

	scredits = server->credits;

	in_flight = server->in_flight;

fs/smb/client/smb2pdu.c

+36 −4
Original line number Diff line number Diff line
@@ -4502,8 +4502,15 @@ smb2_readv_callback(struct mid_q_entry *mid) 
	struct TCP_Server_Info *server = rdata->server;

	struct smb2_hdr *shdr =

				(struct smb2_hdr *)rdata->iov[0].iov_base;

	struct cifs_credits credits = { .value = 0, .instance = 0 };

	struct cifs_credits credits = {

		.value = 0,

		.instance = 0,

		.rreq_debug_id = rdata->rreq->debug_id,

		.rreq_debug_index = rdata->subreq.debug_index,

	};

	struct smb_rqst rqst = { .rq_iov = &rdata->iov[1], .rq_nvec = 1 };

	unsigned int rreq_debug_id = rdata->rreq->debug_id;

	unsigned int subreq_debug_index = rdata->subreq.debug_index;



	if (rdata->got_bytes) {

		rqst.rq_iter	  = rdata->subreq.io_iter;
@@ -4587,10 +4594,16 @@ smb2_readv_callback(struct mid_q_entry *mid) 
		if (rdata->subreq.start < rdata->subreq.rreq->i_size)

			rdata->result = 0;

	}

	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, rdata->credits.value,

			      server->credits, server->in_flight,

			      0, cifs_trace_rw_credits_read_response_clear);

	rdata->credits.value = 0;

	INIT_WORK(&rdata->subreq.work, smb2_readv_worker);

	queue_work(cifsiod_wq, &rdata->subreq.work);

	release_mid(mid);

	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, 0,

			      server->credits, server->in_flight,

			      credits.value, cifs_trace_rw_credits_read_response_add);

	add_credits(server, &credits, 0);

}
@@ -4647,7 +4660,7 @@ smb2_async_readv(struct cifs_io_subrequest *rdata) 
				min_t(int, server->max_credits -

						server->credits, credit_request));



		rc = adjust_credits(server, &rdata->credits, rdata->subreq.len);

		rc = adjust_credits(server, rdata, cifs_trace_rw_credits_call_readv_adjust);

		if (rc)

			goto async_readv_out;
@@ -4766,7 +4779,14 @@ smb2_writev_callback(struct mid_q_entry *mid) 
	struct cifs_tcon *tcon = tlink_tcon(wdata->req->cfile->tlink);

	struct TCP_Server_Info *server = wdata->server;

	struct smb2_write_rsp *rsp = (struct smb2_write_rsp *)mid->resp_buf;

	struct cifs_credits credits = { .value = 0, .instance = 0 };

	struct cifs_credits credits = {

		.value = 0,

		.instance = 0,

		.rreq_debug_id = wdata->rreq->debug_id,

		.rreq_debug_index = wdata->subreq.debug_index,

	};

	unsigned int rreq_debug_id = wdata->rreq->debug_id;

	unsigned int subreq_debug_index = wdata->subreq.debug_index;

	ssize_t result = 0;

	size_t written;
@@ -4837,9 +4857,15 @@ smb2_writev_callback(struct mid_q_entry *mid) 
				      tcon->tid, tcon->ses->Suid,

				      wdata->subreq.start, wdata->subreq.len);



	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, wdata->credits.value,

			      server->credits, server->in_flight,

			      0, cifs_trace_rw_credits_write_response_clear);

	wdata->credits.value = 0;

	cifs_write_subrequest_terminated(wdata, result ?: written, true);

	release_mid(mid);

	trace_smb3_rw_credits(rreq_debug_id, subreq_debug_index, 0,

			      server->credits, server->in_flight,

			      credits.value, cifs_trace_rw_credits_write_response_add);

	add_credits(server, &credits, 0);

}
@@ -4969,7 +4995,7 @@ smb2_async_writev(struct cifs_io_subrequest *wdata) 
				min_t(int, server->max_credits -

						server->credits, credit_request));



		rc = adjust_credits(server, &wdata->credits, io_parms->length);

		rc = adjust_credits(server, wdata, cifs_trace_rw_credits_call_writev_adjust);

		if (rc)

			goto async_writev_out;
@@ -4994,6 +5020,12 @@ smb2_async_writev(struct cifs_io_subrequest *wdata) 
	cifs_small_buf_release(req);

out:

	if (rc) {

		trace_smb3_rw_credits(wdata->rreq->debug_id,

				      wdata->subreq.debug_index,

				      wdata->credits.value,

				      server->credits, server->in_flight,

				      -(int)wdata->credits.value,

				      cifs_trace_rw_credits_write_response_clear);

		add_credits_and_wake_if(wdata->server, &wdata->credits, 0);

		cifs_write_subrequest_terminated(wdata, rc, true);

	}