blob: 7ae87cc4a163fc0dfcae0f65e6d25e9b185c4b91 [file] [log] [blame]
Jens Axboe2056a782006-03-23 20:00:26 +01001/*
Jens Axboe0fe23472006-09-04 15:41:16 +02002 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
Jens Axboe2056a782006-03-23 20:00:26 +01003 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
Jens Axboe2056a782006-03-23 20:00:26 +010018#include <linux/kernel.h>
19#include <linux/blkdev.h>
20#include <linux/blktrace_api.h>
21#include <linux/percpu.h>
22#include <linux/init.h>
23#include <linux/mutex.h>
24#include <linux/debugfs.h>
Olaf Kirchbe1c6342006-12-01 10:39:12 +010025#include <linux/time.h>
Jens Axboe2056a782006-03-23 20:00:26 +010026#include <asm/uaccess.h>
27
Jens Axboe2056a782006-03-23 20:00:26 +010028static unsigned int blktrace_seq __read_mostly = 1;
29
30/*
Olaf Kirchbe1c6342006-12-01 10:39:12 +010031 * Send out a notify message.
32 */
Jens Axboea8630552006-12-04 09:30:58 +010033static void trace_note(struct blk_trace *bt, pid_t pid, int action,
34 const void *data, size_t len)
Olaf Kirchbe1c6342006-12-01 10:39:12 +010035{
36 struct blk_io_trace *t;
Olaf Kirchbe1c6342006-12-01 10:39:12 +010037
38 t = relay_reserve(bt->rchan, sizeof(*t) + len);
Jens Axboed3d9d2a2006-12-04 09:27:41 +010039 if (t) {
40 const int cpu = smp_processor_id();
Olaf Kirchbe1c6342006-12-01 10:39:12 +010041
Jens Axboed3d9d2a2006-12-04 09:27:41 +010042 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
Ingo Molnar2997c8c2008-01-11 13:35:54 +010043 t->time = ktime_to_ns(ktime_get());
Jens Axboed3d9d2a2006-12-04 09:27:41 +010044 t->device = bt->dev;
45 t->action = action;
46 t->pid = pid;
47 t->cpu = cpu;
48 t->pdu_len = len;
49 memcpy((void *) t + sizeof(*t), data, len);
50 }
Olaf Kirchbe1c6342006-12-01 10:39:12 +010051}
52
53/*
Jens Axboe2056a782006-03-23 20:00:26 +010054 * Send out a notify for this process, if we haven't done so since a trace
55 * started
56 */
57static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
58{
Jens Axboea8630552006-12-04 09:30:58 +010059 tsk->btrace_seq = blktrace_seq;
60 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
Olaf Kirchbe1c6342006-12-01 10:39:12 +010061}
Jens Axboe2056a782006-03-23 20:00:26 +010062
Olaf Kirchbe1c6342006-12-01 10:39:12 +010063static void trace_note_time(struct blk_trace *bt)
64{
65 struct timespec now;
66 unsigned long flags;
67 u32 words[2];
68
69 getnstimeofday(&now);
70 words[0] = now.tv_sec;
71 words[1] = now.tv_nsec;
72
73 local_irq_save(flags);
74 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
75 local_irq_restore(flags);
Jens Axboe2056a782006-03-23 20:00:26 +010076}
77
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020078void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
79{
80 int n;
81 va_list args;
Jens Axboe64565912008-05-28 14:45:33 +020082 char *buf;
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020083
Jens Axboe64565912008-05-28 14:45:33 +020084 preempt_disable();
85 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020086 va_start(args, fmt);
Jens Axboe64565912008-05-28 14:45:33 +020087 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020088 va_end(args);
89
Jens Axboe64565912008-05-28 14:45:33 +020090 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
91 preempt_enable();
Alan D. Brunelle9d5f09a2008-05-27 14:54:41 +020092}
93EXPORT_SYMBOL_GPL(__trace_note_message);
94
Jens Axboe2056a782006-03-23 20:00:26 +010095static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
96 pid_t pid)
97{
98 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
99 return 1;
100 if (sector < bt->start_lba || sector > bt->end_lba)
101 return 1;
102 if (bt->pid && pid != bt->pid)
103 return 1;
104
105 return 0;
106}
107
108/*
109 * Data direction bit lookup
110 */
111static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) };
112
113/*
114 * Bio action bits of interest
115 */
Jens Axboe7457e6e2006-07-23 02:12:01 +0200116static u32 bio_act[9] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD), 0, 0, 0, BLK_TC_ACT(BLK_TC_META) };
Jens Axboe2056a782006-03-23 20:00:26 +0100117
118/*
119 * More could be added as needed, taking care to increment the decrementer
120 * to get correct indexing
121 */
122#define trace_barrier_bit(rw) \
123 (((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0))
124#define trace_sync_bit(rw) \
125 (((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1))
Nathan Scott40359cc2006-07-06 10:03:28 +0200126#define trace_ahead_bit(rw) \
Milton Millerad01b1c2006-07-25 15:04:13 +0200127 (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD))
Jens Axboe7457e6e2006-07-23 02:12:01 +0200128#define trace_meta_bit(rw) \
129 (((rw) & (1 << BIO_RW_META)) >> (BIO_RW_META - 3))
Jens Axboe2056a782006-03-23 20:00:26 +0100130
131/*
132 * The worker for the various blk_add_trace*() types. Fills out a
133 * blk_io_trace structure and places it in a per-cpu subbuffer.
134 */
135void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
136 int rw, u32 what, int error, int pdu_len, void *pdu_data)
137{
138 struct task_struct *tsk = current;
139 struct blk_io_trace *t;
140 unsigned long flags;
141 unsigned long *sequence;
142 pid_t pid;
143 int cpu;
144
145 if (unlikely(bt->trace_state != Blktrace_running))
146 return;
147
148 what |= ddir_act[rw & WRITE];
149 what |= bio_act[trace_barrier_bit(rw)];
150 what |= bio_act[trace_sync_bit(rw)];
Nathan Scott40359cc2006-07-06 10:03:28 +0200151 what |= bio_act[trace_ahead_bit(rw)];
Jens Axboe7457e6e2006-07-23 02:12:01 +0200152 what |= bio_act[trace_meta_bit(rw)];
Jens Axboe2056a782006-03-23 20:00:26 +0100153
154 pid = tsk->pid;
155 if (unlikely(act_log_check(bt, what, sector, pid)))
156 return;
157
158 /*
159 * A word about the locking here - we disable interrupts to reserve
160 * some space in the relay per-cpu buffer, to prevent an irq
161 * from coming in and stepping on our toes. Once reserved, it's
162 * enough to get preemption disabled to prevent read of this data
163 * before we are through filling it. get_cpu()/put_cpu() does this
164 * for us
165 */
166 local_irq_save(flags);
167
168 if (unlikely(tsk->btrace_seq != blktrace_seq))
169 trace_note_tsk(bt, tsk);
170
171 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
172 if (t) {
173 cpu = smp_processor_id();
174 sequence = per_cpu_ptr(bt->sequence, cpu);
175
176 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
177 t->sequence = ++(*sequence);
Ingo Molnar2997c8c2008-01-11 13:35:54 +0100178 t->time = ktime_to_ns(ktime_get());
Jens Axboe2056a782006-03-23 20:00:26 +0100179 t->sector = sector;
180 t->bytes = bytes;
181 t->action = what;
182 t->pid = pid;
183 t->device = bt->dev;
184 t->cpu = cpu;
185 t->error = error;
186 t->pdu_len = pdu_len;
187
188 if (pdu_len)
189 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
190 }
191
192 local_irq_restore(flags);
193}
194
195EXPORT_SYMBOL_GPL(__blk_add_trace);
196
197static struct dentry *blk_tree_root;
Jens Axboe11a57152008-01-11 13:37:01 +0100198static DEFINE_MUTEX(blk_tree_mutex);
Jens Axboe2056a782006-03-23 20:00:26 +0100199static unsigned int root_users;
200
201static inline void blk_remove_root(void)
202{
203 if (blk_tree_root) {
204 debugfs_remove(blk_tree_root);
205 blk_tree_root = NULL;
206 }
207}
208
209static void blk_remove_tree(struct dentry *dir)
210{
211 mutex_lock(&blk_tree_mutex);
212 debugfs_remove(dir);
213 if (--root_users == 0)
214 blk_remove_root();
215 mutex_unlock(&blk_tree_mutex);
216}
217
218static struct dentry *blk_create_tree(const char *blk_name)
219{
220 struct dentry *dir = NULL;
Aneesh Kumar K.V35fc51e2007-11-21 12:25:41 +0100221 int created = 0;
Jens Axboe2056a782006-03-23 20:00:26 +0100222
223 mutex_lock(&blk_tree_mutex);
224
225 if (!blk_tree_root) {
226 blk_tree_root = debugfs_create_dir("block", NULL);
227 if (!blk_tree_root)
228 goto err;
Aneesh Kumar K.V35fc51e2007-11-21 12:25:41 +0100229 created = 1;
Jens Axboe2056a782006-03-23 20:00:26 +0100230 }
231
232 dir = debugfs_create_dir(blk_name, blk_tree_root);
233 if (dir)
234 root_users++;
Aneesh Kumar K.V35fc51e2007-11-21 12:25:41 +0100235 else {
236 /* Delete root only if we created it */
237 if (created)
238 blk_remove_root();
239 }
Jens Axboe2056a782006-03-23 20:00:26 +0100240
241err:
242 mutex_unlock(&blk_tree_mutex);
243 return dir;
244}
245
246static void blk_trace_cleanup(struct blk_trace *bt)
247{
248 relay_close(bt->rchan);
249 debugfs_remove(bt->dropped_file);
250 blk_remove_tree(bt->dir);
251 free_percpu(bt->sequence);
Jens Axboe64565912008-05-28 14:45:33 +0200252 free_percpu(bt->msg_data);
Jens Axboe2056a782006-03-23 20:00:26 +0100253 kfree(bt);
254}
255
Christof Schmitt6da127a2008-01-11 10:09:43 +0100256int blk_trace_remove(struct request_queue *q)
Jens Axboe2056a782006-03-23 20:00:26 +0100257{
258 struct blk_trace *bt;
259
260 bt = xchg(&q->blk_trace, NULL);
261 if (!bt)
262 return -EINVAL;
263
264 if (bt->trace_state == Blktrace_setup ||
265 bt->trace_state == Blktrace_stopped)
266 blk_trace_cleanup(bt);
267
268 return 0;
269}
Christof Schmitt6da127a2008-01-11 10:09:43 +0100270EXPORT_SYMBOL_GPL(blk_trace_remove);
Jens Axboe2056a782006-03-23 20:00:26 +0100271
272static int blk_dropped_open(struct inode *inode, struct file *filp)
273{
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700274 filp->private_data = inode->i_private;
Jens Axboe2056a782006-03-23 20:00:26 +0100275
276 return 0;
277}
278
279static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
280 size_t count, loff_t *ppos)
281{
282 struct blk_trace *bt = filp->private_data;
283 char buf[16];
284
285 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
286
287 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
288}
289
Arjan van de Ven2b8693c2007-02-12 00:55:32 -0800290static const struct file_operations blk_dropped_fops = {
Jens Axboe2056a782006-03-23 20:00:26 +0100291 .owner = THIS_MODULE,
292 .open = blk_dropped_open,
293 .read = blk_dropped_read,
294};
295
296/*
297 * Keep track of how many times we encountered a full subbuffer, to aid
298 * the user space app in telling how many lost events there were.
299 */
300static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
301 void *prev_subbuf, size_t prev_padding)
302{
303 struct blk_trace *bt;
304
305 if (!relay_buf_full(buf))
306 return 1;
307
308 bt = buf->chan->private_data;
309 atomic_inc(&bt->dropped);
310 return 0;
311}
312
313static int blk_remove_buf_file_callback(struct dentry *dentry)
314{
315 debugfs_remove(dentry);
316 return 0;
317}
318
319static struct dentry *blk_create_buf_file_callback(const char *filename,
320 struct dentry *parent,
321 int mode,
322 struct rchan_buf *buf,
323 int *is_global)
324{
325 return debugfs_create_file(filename, mode, parent, buf,
326 &relay_file_operations);
327}
328
329static struct rchan_callbacks blk_relay_callbacks = {
330 .subbuf_start = blk_subbuf_start_callback,
331 .create_buf_file = blk_create_buf_file_callback,
332 .remove_buf_file = blk_remove_buf_file_callback,
333};
334
335/*
336 * Setup everything required to start tracing
337 */
Christof Schmitt6da127a2008-01-11 10:09:43 +0100338int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
Arnd Bergmann171044d42007-10-09 13:23:53 +0200339 struct blk_user_trace_setup *buts)
Jens Axboe2056a782006-03-23 20:00:26 +0100340{
Jens Axboe2056a782006-03-23 20:00:26 +0100341 struct blk_trace *old_bt, *bt = NULL;
342 struct dentry *dir = NULL;
Jens Axboe2056a782006-03-23 20:00:26 +0100343 int ret, i;
344
Arnd Bergmann171044d42007-10-09 13:23:53 +0200345 if (!buts->buf_size || !buts->buf_nr)
Jens Axboe2056a782006-03-23 20:00:26 +0100346 return -EINVAL;
347
Christof Schmitt6da127a2008-01-11 10:09:43 +0100348 strcpy(buts->name, name);
Jens Axboe2056a782006-03-23 20:00:26 +0100349
350 /*
351 * some device names have larger paths - convert the slashes
352 * to underscores for this to work as expected
353 */
Arnd Bergmann171044d42007-10-09 13:23:53 +0200354 for (i = 0; i < strlen(buts->name); i++)
355 if (buts->name[i] == '/')
356 buts->name[i] = '_';
Jens Axboe2056a782006-03-23 20:00:26 +0100357
358 ret = -ENOMEM;
359 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
360 if (!bt)
361 goto err;
362
363 bt->sequence = alloc_percpu(unsigned long);
364 if (!bt->sequence)
365 goto err;
366
Jens Axboe64565912008-05-28 14:45:33 +0200367 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG);
368 if (!bt->msg_data)
369 goto err;
370
Jens Axboe2056a782006-03-23 20:00:26 +0100371 ret = -ENOENT;
Arnd Bergmann171044d42007-10-09 13:23:53 +0200372 dir = blk_create_tree(buts->name);
Jens Axboe2056a782006-03-23 20:00:26 +0100373 if (!dir)
374 goto err;
375
376 bt->dir = dir;
Christof Schmitt6da127a2008-01-11 10:09:43 +0100377 bt->dev = dev;
Jens Axboe2056a782006-03-23 20:00:26 +0100378 atomic_set(&bt->dropped, 0);
379
380 ret = -EIO;
381 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
382 if (!bt->dropped_file)
383 goto err;
384
Arnd Bergmann171044d42007-10-09 13:23:53 +0200385 bt->rchan = relay_open("trace", dir, buts->buf_size,
386 buts->buf_nr, &blk_relay_callbacks, bt);
Jens Axboe2056a782006-03-23 20:00:26 +0100387 if (!bt->rchan)
388 goto err;
Jens Axboe2056a782006-03-23 20:00:26 +0100389
Arnd Bergmann171044d42007-10-09 13:23:53 +0200390 bt->act_mask = buts->act_mask;
Jens Axboe2056a782006-03-23 20:00:26 +0100391 if (!bt->act_mask)
392 bt->act_mask = (u16) -1;
393
Arnd Bergmann171044d42007-10-09 13:23:53 +0200394 bt->start_lba = buts->start_lba;
395 bt->end_lba = buts->end_lba;
Jens Axboe2056a782006-03-23 20:00:26 +0100396 if (!bt->end_lba)
397 bt->end_lba = -1ULL;
398
Arnd Bergmann171044d42007-10-09 13:23:53 +0200399 bt->pid = buts->pid;
Jens Axboe2056a782006-03-23 20:00:26 +0100400 bt->trace_state = Blktrace_setup;
401
402 ret = -EBUSY;
403 old_bt = xchg(&q->blk_trace, bt);
404 if (old_bt) {
405 (void) xchg(&q->blk_trace, old_bt);
406 goto err;
407 }
408
409 return 0;
410err:
411 if (dir)
412 blk_remove_tree(dir);
413 if (bt) {
414 if (bt->dropped_file)
415 debugfs_remove(bt->dropped_file);
Alan Sterna1205862006-12-06 20:32:37 -0800416 free_percpu(bt->sequence);
Jens Axboe64565912008-05-28 14:45:33 +0200417 free_percpu(bt->msg_data);
Jens Axboe2056a782006-03-23 20:00:26 +0100418 if (bt->rchan)
419 relay_close(bt->rchan);
420 kfree(bt);
421 }
422 return ret;
423}
424
Christof Schmitt6da127a2008-01-11 10:09:43 +0100425int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
426 char __user *arg)
Arnd Bergmann171044d42007-10-09 13:23:53 +0200427{
428 struct blk_user_trace_setup buts;
429 int ret;
430
431 ret = copy_from_user(&buts, arg, sizeof(buts));
432 if (ret)
433 return -EFAULT;
434
Christof Schmitt6da127a2008-01-11 10:09:43 +0100435 ret = do_blk_trace_setup(q, name, dev, &buts);
Arnd Bergmann171044d42007-10-09 13:23:53 +0200436 if (ret)
437 return ret;
438
439 if (copy_to_user(arg, &buts, sizeof(buts)))
440 return -EFAULT;
441
442 return 0;
443}
Christof Schmitt6da127a2008-01-11 10:09:43 +0100444EXPORT_SYMBOL_GPL(blk_trace_setup);
Arnd Bergmann171044d42007-10-09 13:23:53 +0200445
Christof Schmitt6da127a2008-01-11 10:09:43 +0100446int blk_trace_startstop(struct request_queue *q, int start)
Jens Axboe2056a782006-03-23 20:00:26 +0100447{
448 struct blk_trace *bt;
449 int ret;
450
451 if ((bt = q->blk_trace) == NULL)
452 return -EINVAL;
453
454 /*
455 * For starting a trace, we can transition from a setup or stopped
456 * trace. For stopping a trace, the state must be running
457 */
458 ret = -EINVAL;
459 if (start) {
460 if (bt->trace_state == Blktrace_setup ||
461 bt->trace_state == Blktrace_stopped) {
462 blktrace_seq++;
463 smp_mb();
464 bt->trace_state = Blktrace_running;
Olaf Kirchbe1c6342006-12-01 10:39:12 +0100465
466 trace_note_time(bt);
Jens Axboe2056a782006-03-23 20:00:26 +0100467 ret = 0;
468 }
469 } else {
470 if (bt->trace_state == Blktrace_running) {
471 bt->trace_state = Blktrace_stopped;
472 relay_flush(bt->rchan);
473 ret = 0;
474 }
475 }
476
477 return ret;
478}
Christof Schmitt6da127a2008-01-11 10:09:43 +0100479EXPORT_SYMBOL_GPL(blk_trace_startstop);
Jens Axboe2056a782006-03-23 20:00:26 +0100480
481/**
482 * blk_trace_ioctl: - handle the ioctls associated with tracing
483 * @bdev: the block device
484 * @cmd: the ioctl cmd
485 * @arg: the argument data, if any
486 *
487 **/
488int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
489{
Jens Axboe165125e2007-07-24 09:28:11 +0200490 struct request_queue *q;
Jens Axboe2056a782006-03-23 20:00:26 +0100491 int ret, start = 0;
Christof Schmitt6da127a2008-01-11 10:09:43 +0100492 char b[BDEVNAME_SIZE];
Jens Axboe2056a782006-03-23 20:00:26 +0100493
494 q = bdev_get_queue(bdev);
495 if (!q)
496 return -ENXIO;
497
498 mutex_lock(&bdev->bd_mutex);
499
500 switch (cmd) {
501 case BLKTRACESETUP:
Jean Delvaref36f21e2008-05-12 14:02:33 -0700502 bdevname(bdev, b);
Christof Schmitt6da127a2008-01-11 10:09:43 +0100503 ret = blk_trace_setup(q, b, bdev->bd_dev, arg);
Jens Axboe2056a782006-03-23 20:00:26 +0100504 break;
505 case BLKTRACESTART:
506 start = 1;
507 case BLKTRACESTOP:
508 ret = blk_trace_startstop(q, start);
509 break;
510 case BLKTRACETEARDOWN:
511 ret = blk_trace_remove(q);
512 break;
513 default:
514 ret = -ENOTTY;
515 break;
516 }
517
518 mutex_unlock(&bdev->bd_mutex);
519 return ret;
520}
521
522/**
523 * blk_trace_shutdown: - stop and cleanup trace structures
524 * @q: the request queue associated with the device
525 *
526 **/
Jens Axboe165125e2007-07-24 09:28:11 +0200527void blk_trace_shutdown(struct request_queue *q)
Jens Axboe2056a782006-03-23 20:00:26 +0100528{
Alexey Dobriyan6c5c9342006-09-29 01:59:40 -0700529 if (q->blk_trace) {
530 blk_trace_startstop(q, 0);
531 blk_trace_remove(q);
532 }
Jens Axboe2056a782006-03-23 20:00:26 +0100533}