plugin_blk.c

/*
 * Copyright (C) 2009 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License (not later!)
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <linux/blktrace_api.h>

#include "trace-cmd.h"

#define MINORBITS	20
#define MINORMASK	((1U << MINORBITS) - 1)
#define MAJOR(dev)	((unsigned int) ((dev) >> MINORBITS))
#define MINOR(dev)	((unsigned int) ((dev) & MINORMASK))
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))

struct blk_data {
	unsigned long long	sector;
	struct event_format	*event;
	unsigned int		action;
	unsigned int		pid;
	unsigned int		device;
	unsigned int		bytes;
	unsigned int		error;
	void			*pdu_data;
	unsigned short		pdu_len;
};

static void fill_rwbs(char *rwbs, int action, unsigned int bytes)
{
	int i = 0;
	int tc = action >> BLK_TC_SHIFT;

	if (action == BLK_TN_MESSAGE) {
		rwbs[i++] = 'N';
		goto out;
	}

#if defined(HAVE_BLK_TC_FLUSH)
	if (tc & BLK_TC_FLUSH)
		rwbs[i++] = 'F';
#endif

	if (tc & BLK_TC_DISCARD)
		rwbs[i++] = 'D';
	else if (tc & BLK_TC_WRITE)
		rwbs[i++] = 'W';
	else if (bytes)
		rwbs[i++] = 'R';
	else
		rwbs[i++] = 'N';

#if defined(HAVE_BLK_TC_FLUSH)
	if (tc & BLK_TC_FUA)
		rwbs[i++] = 'F';
#endif
	if (tc & BLK_TC_AHEAD)
		rwbs[i++] = 'A';
#if !defined(HAVE_BLK_TC_FLUSH)
	if (tc & BLK_TC_BARRIER)
		rwbs[i++] = 'B';
#endif
	if (tc & BLK_TC_SYNC)
		rwbs[i++] = 'S';
	if (tc & BLK_TC_META)
		rwbs[i++] = 'M';
out:
	rwbs[i] = '\0';
}

static int log_action(struct trace_seq *s, struct blk_data *data,
		      const char *act)
{
	char rwbs[6];

	fill_rwbs(rwbs, data->action, data->bytes);
	return trace_seq_printf(s, "%3d,%-3d %2s %3s ",
				MAJOR(data->device),
				MINOR(data->device), act, rwbs);
}

static void blk_log_msg(struct trace_seq *s, void *data, int len)
{
	trace_seq_printf(s, "%.*s", len, (char *)data);
}

static int blk_log_dump_pdu(struct trace_seq *s, const unsigned char *pdu_buf,
			    int pdu_len)
{
	int i, end, ret;

	if (!pdu_len)
		return 1;

	/* find the last zero that needs to be printed */
	for (end = pdu_len - 1; end >= 0; end--)
		if (pdu_buf[end])
			break;
	end++;

	if (!trace_seq_putc(s, '('))
		return 0;

	for (i = 0; i < pdu_len; i++) {

		ret = trace_seq_printf(s, "%s%02x",
				       i == 0 ? "" : " ", pdu_buf[i]);
		if (!ret)
			return ret;

		/*
		 * stop when the rest is just zeroes and indicate so
		 * with a ".." appended
		 */
		if (i == end && end != pdu_len - 1)
			return trace_seq_puts(s, " ..) ");
	}

	return trace_seq_puts(s, ") ");
}

static unsigned int t_sec(int bytes)
{
	return bytes >> 9;
}

static unsigned int be32_to_cpu(unsigned int val)
{
	unsigned int swap;

	if (tracecmd_host_bigendian())
		return val;

	swap = ((val & 0xffULL) << 24) |
		((val & (0xffULL << 8)) << 8) |
		((val & (0xffULL << 16)) >> 8) |
		((val & (0xffULL << 24)) >> 24);

	return swap;
}

static unsigned long long be64_to_cpu(unsigned long long val)
{
	unsigned long long swap;

	if (tracecmd_host_bigendian())
		return val;

	swap = ((val & 0xffULL) << 56) |
		((val & (0xffULL << 8)) << 40) |
		((val & (0xffULL << 16)) << 24) |
		((val & (0xffULL << 24)) << 8) |
		((val & (0xffULL << 32)) >> 8) |
		((val & (0xffULL << 40)) >> 24) |
		((val & (0xffULL << 48)) >> 40) |
		((val & (0xffULL << 56)) >> 56);

	return swap;
}

static unsigned long long get_pdu_int(void *data)
{
	const unsigned long long *val = data;
	return be64_to_cpu(*val);
}

static void get_pdu_remap(void *pdu_data,
			  struct blk_io_trace_remap *r)
{
	const struct blk_io_trace_remap *__r = pdu_data;
	unsigned long long sector_from = __r->sector_from;

	r->device_from = be32_to_cpu(__r->device_from);
	r->device_to   = be32_to_cpu(__r->device_to);
	r->sector_from = be64_to_cpu(sector_from);
}

static int blk_log_remap(struct trace_seq *s, struct blk_data *data)
{
	struct blk_io_trace_remap r = { .device_from = 0, };

	get_pdu_remap(data->pdu_data, &r);
	return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
				data->sector, t_sec(data->bytes),
				MAJOR(r.device_from), MINOR(r.device_from),
				(unsigned long long)r.sector_from);
}

static int blk_log_split(struct trace_seq *s, struct blk_data *data)
{
	const char *cmd;

	cmd = pevent_data_comm_from_pid(data->event->pevent, data->pid);

	return trace_seq_printf(s, "%llu / %llu [%s]\n", data->sector,
				get_pdu_int(data->pdu_data), cmd);
}

static int blk_log_plug(struct trace_seq *s, struct blk_data *data)
{
	const char *cmd;

	cmd = pevent_data_comm_from_pid(data->event->pevent, data->pid);

	return trace_seq_printf(s, "[%s]\n", cmd);
}

static int blk_log_unplug(struct trace_seq *s, struct blk_data *data)
{
	const char *cmd;

	cmd = pevent_data_comm_from_pid(data->event->pevent, data->pid);

	return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(data->pdu_data));
}

static int blk_log_with_error(struct trace_seq *s, struct blk_data *data)
{
	if (data->action & BLK_TC_ACT(BLK_TC_PC)) {
		blk_log_dump_pdu(s, data->pdu_data, data->pdu_len);
		trace_seq_printf(s, "[%d]\n", data->error);
		return 0;
	} else {
		if (t_sec(data->bytes))
			return trace_seq_printf(s, "%llu + %u [%d]\n",
						data->sector,
						t_sec(data->bytes),
						data->error);
		return trace_seq_printf(s, "%llu [%d]\n",
					data->sector, data->error);
	}
}

static int blk_log_generic(struct trace_seq *s, struct blk_data *data)
{
	const char *cmd;

	cmd = pevent_data_comm_from_pid(data->event->pevent, data->pid);

	if (data->action & BLK_TC_ACT(BLK_TC_PC)) {
		int ret;

		ret = trace_seq_printf(s, "%u ", data->bytes);
		if (!ret)
			return 0;
		ret = blk_log_dump_pdu(s, data->pdu_data, data->pdu_len);
		if (!ret)
			return 0;
		return trace_seq_printf(s, "[%s]\n", cmd);
	} else {
		if (t_sec(data->bytes))
			return trace_seq_printf(s, "%llu + %u [%s]\n",
						data->sector,
						t_sec(data->bytes), cmd);
		return trace_seq_printf(s, "[%s]\n", cmd);
	}
}

static const struct {
	const char *act[2];
	int	   (*print)(struct trace_seq *s, struct blk_data *data);
} what2act[] = {
	[__BLK_TA_QUEUE]	= {{  "Q", "queue" },	   blk_log_generic },
	[__BLK_TA_BACKMERGE]	= {{  "M", "backmerge" },  blk_log_generic },
	[__BLK_TA_FRONTMERGE]	= {{  "F", "frontmerge" }, blk_log_generic },
	[__BLK_TA_GETRQ]	= {{  "G", "getrq" },	   blk_log_generic },
	[__BLK_TA_SLEEPRQ]	= {{  "S", "sleeprq" },	   blk_log_generic },
	[__BLK_TA_REQUEUE]	= {{  "R", "requeue" },	   blk_log_with_error },
	[__BLK_TA_ISSUE]	= {{  "D", "issue" },	   blk_log_generic },
	[__BLK_TA_COMPLETE]	= {{  "C", "complete" },   blk_log_with_error },
	[__BLK_TA_PLUG]		= {{  "P", "plug" },	   blk_log_plug },
	[__BLK_TA_UNPLUG_IO]	= {{  "U", "unplug_io" },  blk_log_unplug },
	[__BLK_TA_UNPLUG_TIMER]	= {{ "UT", "unplug_timer" }, blk_log_unplug },
	[__BLK_TA_INSERT]	= {{  "I", "insert" },	   blk_log_generic },
	[__BLK_TA_SPLIT]	= {{  "X", "split" },	   blk_log_split },
	[__BLK_TA_BOUNCE]	= {{  "B", "bounce" },	   blk_log_generic },
	[__BLK_TA_REMAP]	= {{  "A", "remap" },	   blk_log_remap },
};

static int blktrace_handler(struct trace_seq *s, struct record *record,
			    struct event_format *event, void *context)
{
	struct format_field *field;
	unsigned long long val;
	void *data = record->data;
	struct blk_data blk_data;
	unsigned short what;
	int long_act = 0;

	field = pevent_find_field(event, "action");
	if (!field)
		return 1;
	if (pevent_read_number_field(field, data, &val))
		return 1;
	blk_data.action = val;

	field = pevent_find_field(event, "bytes");
	if (!field)
		return 1;
	if (pevent_read_number_field(field, data, &val))
		return 1;
	blk_data.bytes = val;

	field = pevent_find_field(event, "device");
	if (!field)
		return 1;
	if (pevent_read_number_field(field, data, &val))
		return 1;
	blk_data.device = val;

	field = pevent_find_field(event, "pdu_len");
	if (!field)
		return 1;
	if (pevent_read_number_field(field, data, &val))
		return 1;
	blk_data.pdu_len = val;

	field = pevent_find_field(event, "data");
	if (!field)
		return 1;
	blk_data.pdu_data = data + field->offset;

	field = pevent_find_field(event, "sector");
	if (!field)
		return 1;
	if (pevent_read_number_field(field, data, &blk_data.sector))
		return 1;

	field = pevent_find_field(event, "pid");
	if (!field)
		return 1;
	if (pevent_read_number_field(field, data, &val))
		return 1;
	blk_data.pid = val;

	field = pevent_find_field(event, "error");
	if (!field)
		return 1;
	if (pevent_read_number_field(field, data, &val))
		return 1;
	blk_data.error = val;

	blk_data.event = event;


	what	   = blk_data.action & ((1 << BLK_TC_SHIFT) - 1);

	if (blk_data.action == BLK_TN_MESSAGE) {
		log_action(s, &blk_data, "m");
		blk_log_msg(s, blk_data.pdu_data, blk_data.pdu_len);
		goto out;
	}

	if (what == 0 || what >= ARRAY_SIZE(what2act))
		trace_seq_printf(s, "Unknown action %x\n", what);
	else {
		log_action(s, &blk_data, what2act[what].act[long_act]);
		what2act[what].print(s, &blk_data);
	}

 out:
	return 0;
}

int PEVENT_PLUGIN_LOADER(struct pevent *pevent)
{
	pevent_register_event_handler(pevent, -1, "ftrace", "blktrace",
				      blktrace_handler, NULL);
	return 0;
}