summaryrefslogtreecommitdiffstats
path: root/fs/bcachefs/thread_with_file.c
blob: b1af7ac430f662aa2b827d0c6550ef6187089352 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
// SPDX-License-Identifier: GPL-2.0
#ifndef NO_BCACHEFS_FS

#include "bcachefs.h"
#include "thread_with_file.h"

#include <linux/anon_inodes.h>
#include <linux/file.h>
#include <linux/kthread.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/sched/sysctl.h>

void bch2_thread_with_file_exit(struct thread_with_file *thr)
{
	if (thr->task) {
		kthread_stop(thr->task);
		put_task_struct(thr->task);
	}
}

int bch2_run_thread_with_file(struct thread_with_file *thr,
			      const struct file_operations *fops,
			      int (*fn)(void *))
{
	struct file *file = NULL;
	int ret, fd = -1;
	unsigned fd_flags = O_CLOEXEC;

	if (fops->read && fops->write)
		fd_flags |= O_RDWR;
	else if (fops->read)
		fd_flags |= O_RDONLY;
	else if (fops->write)
		fd_flags |= O_WRONLY;

	char name[TASK_COMM_LEN];
	get_task_comm(name, current);

	thr->ret = 0;
	thr->task = kthread_create(fn, thr, "%s", name);
	ret = PTR_ERR_OR_ZERO(thr->task);
	if (ret)
		return ret;

	ret = get_unused_fd_flags(fd_flags);
	if (ret < 0)
		goto err;
	fd = ret;

	file = anon_inode_getfile(name, fops, thr, fd_flags);
	ret = PTR_ERR_OR_ZERO(file);
	if (ret)
		goto err;

	get_task_struct(thr->task);
	wake_up_process(thr->task);
	fd_install(fd, file);
	return fd;
err:
	if (fd >= 0)
		put_unused_fd(fd);
	if (thr->task)
		kthread_stop(thr->task);
	return ret;
}

/* stdio_redirect */

static bool stdio_redirect_has_input(struct stdio_redirect *stdio)
{
	return stdio->input.buf.nr || stdio->done;
}

static bool stdio_redirect_has_output(struct stdio_redirect *stdio)
{
	return stdio->output.buf.nr || stdio->done;
}

#define STDIO_REDIRECT_BUFSIZE		4096

static bool stdio_redirect_has_input_space(struct stdio_redirect *stdio)
{
	return stdio->input.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
}

static bool stdio_redirect_has_output_space(struct stdio_redirect *stdio)
{
	return stdio->output.buf.nr < STDIO_REDIRECT_BUFSIZE || stdio->done;
}

static void stdio_buf_init(struct stdio_buf *buf)
{
	spin_lock_init(&buf->lock);
	init_waitqueue_head(&buf->wait);
	darray_init(&buf->buf);
}

/* thread_with_stdio */

static void thread_with_stdio_done(struct thread_with_stdio *thr)
{
	thr->thr.done = true;
	thr->stdio.done = true;
	wake_up(&thr->stdio.input.wait);
	wake_up(&thr->stdio.output.wait);
}

static ssize_t thread_with_stdio_read(struct file *file, char __user *ubuf,
				      size_t len, loff_t *ppos)
{
	struct thread_with_stdio *thr =
		container_of(file->private_data, struct thread_with_stdio, thr);
	struct stdio_buf *buf = &thr->stdio.output;
	size_t copied = 0, b;
	int ret = 0;

	if (!(file->f_flags & O_NONBLOCK)) {
		ret = wait_event_interruptible(buf->wait, stdio_redirect_has_output(&thr->stdio));
		if (ret)
			return ret;
	} else if (!stdio_redirect_has_output(&thr->stdio))
		return -EAGAIN;

	while (len && buf->buf.nr) {
		if (fault_in_writeable(ubuf, len) == len) {
			ret = -EFAULT;
			break;
		}

		spin_lock_irq(&buf->lock);
		b = min_t(size_t, len, buf->buf.nr);

		if (b && !copy_to_user_nofault(ubuf, buf->buf.data, b)) {
			ubuf	+= b;
			len	-= b;
			copied	+= b;
			buf->buf.nr -= b;
			memmove(buf->buf.data,
				buf->buf.data + b,
				buf->buf.nr);
		}
		spin_unlock_irq(&buf->lock);
	}

	return copied ?: ret;
}

static int thread_with_stdio_release(struct inode *inode, struct file *file)
{
	struct thread_with_stdio *thr =
		container_of(file->private_data, struct thread_with_stdio, thr);

	thread_with_stdio_done(thr);
	bch2_thread_with_file_exit(&thr->thr);
	darray_exit(&thr->stdio.input.buf);
	darray_exit(&thr->stdio.output.buf);
	thr->ops->exit(thr);
	return 0;
}

static ssize_t thread_with_stdio_write(struct file *file, const char __user *ubuf,
				       size_t len, loff_t *ppos)
{
	struct thread_with_stdio *thr =
		container_of(file->private_data, struct thread_with_stdio, thr);
	struct stdio_buf *buf = &thr->stdio.input;
	size_t copied = 0;
	ssize_t ret = 0;

	while (len) {
		if (thr->thr.done) {
			ret = -EPIPE;
			break;
		}

		size_t b = len - fault_in_readable(ubuf, len);
		if (!b) {
			ret = -EFAULT;
			break;
		}

		spin_lock(&buf->lock);
		if (buf->buf.nr < STDIO_REDIRECT_BUFSIZE)
			darray_make_room_gfp(&buf->buf,
				min(b, STDIO_REDIRECT_BUFSIZE - buf->buf.nr), GFP_NOWAIT);
		b = min(len, darray_room(buf->buf));

		if (b && !copy_from_user_nofault(&darray_top(buf->buf), ubuf, b)) {
			buf->buf.nr += b;
			ubuf	+= b;
			len	-= b;
			copied	+= b;
		}
		spin_unlock(&buf->lock);

		if (b) {
			wake_up(&buf->wait);
		} else {
			if ((file->f_flags & O_NONBLOCK)) {
				ret = -EAGAIN;
				break;
			}

			ret = wait_event_interruptible(buf->wait,
					stdio_redirect_has_input_space(&thr->stdio));
			if (ret)
				break;
		}
	}

	return copied ?: ret;
}

static __poll_t thread_with_stdio_poll(struct file *file, struct poll_table_struct *wait)
{
	struct thread_with_stdio *thr =
		container_of(file->private_data, struct thread_with_stdio, thr);

	poll_wait(file, &thr->stdio.output.wait, wait);
	poll_wait(file, &thr->stdio.input.wait, wait);

	__poll_t mask = 0;

	if (stdio_redirect_has_output(&thr->stdio))
		mask |= EPOLLIN;
	if (stdio_redirect_has_input_space(&thr->stdio))
		mask |= EPOLLOUT;
	if (thr->thr.done)
		mask |= EPOLLHUP|EPOLLERR;
	return mask;
}

static __poll_t thread_with_stdout_poll(struct file *file, struct poll_table_struct *wait)
{
	struct thread_with_stdio *thr =
		container_of(file->private_data, struct thread_with_stdio, thr);

	poll_wait(file, &thr->stdio.output.wait, wait);

	__poll_t mask = 0;

	if (stdio_redirect_has_output(&thr->stdio))
		mask |= EPOLLIN;
	if (thr->thr.done)
		mask |= EPOLLHUP|EPOLLERR;
	return mask;
}

static int thread_with_stdio_flush(struct file *file, fl_owner_t id)
{
	struct thread_with_stdio *thr =
		container_of(file->private_data, struct thread_with_stdio, thr);

	return thr->thr.ret;
}

static long thread_with_stdio_ioctl(struct file *file, unsigned int cmd, unsigned long p)
{
	struct thread_with_stdio *thr =
		container_of(file->private_data, struct thread_with_stdio, thr);

	if (thr->ops->unlocked_ioctl)
		return thr->ops->unlocked_ioctl(thr, cmd, p);
	return -ENOTTY;
}

static const struct file_operations thread_with_stdio_fops = {
	.llseek		= no_llseek,
	.read		= thread_with_stdio_read,
	.write		= thread_with_stdio_write,
	.poll		= thread_with_stdio_poll,
	.flush		= thread_with_stdio_flush,
	.release	= thread_with_stdio_release,
	.unlocked_ioctl	= thread_with_stdio_ioctl,
};

static const struct file_operations thread_with_stdout_fops = {
	.llseek		= no_llseek,
	.read		= thread_with_stdio_read,
	.poll		= thread_with_stdout_poll,
	.flush		= thread_with_stdio_flush,
	.release	= thread_with_stdio_release,
	.unlocked_ioctl	= thread_with_stdio_ioctl,
};

static int thread_with_stdio_fn(void *arg)
{
	struct thread_with_stdio *thr = arg;

	thr->thr.ret = thr->ops->fn(thr);

	thread_with_stdio_done(thr);
	return 0;
}

void bch2_thread_with_stdio_init(struct thread_with_stdio *thr,
				 const struct thread_with_stdio_ops *ops)
{
	stdio_buf_init(&thr->stdio.input);
	stdio_buf_init(&thr->stdio.output);
	thr->ops = ops;
}

int __bch2_run_thread_with_stdio(struct thread_with_stdio *thr)
{
	return bch2_run_thread_with_file(&thr->thr, &thread_with_stdio_fops, thread_with_stdio_fn);
}

int bch2_run_thread_with_stdio(struct thread_with_stdio *thr,
			       const struct thread_with_stdio_ops *ops)
{
	bch2_thread_with_stdio_init(thr, ops);

	return __bch2_run_thread_with_stdio(thr);
}

int bch2_run_thread_with_stdout(struct thread_with_stdio *thr,
				const struct thread_with_stdio_ops *ops)
{
	stdio_buf_init(&thr->stdio.input);
	stdio_buf_init(&thr->stdio.output);
	thr->ops = ops;

	return bch2_run_thread_with_file(&thr->thr, &thread_with_stdout_fops, thread_with_stdio_fn);
}
EXPORT_SYMBOL_GPL(bch2_run_thread_with_stdout);

int bch2_stdio_redirect_read(struct stdio_redirect *stdio, char *ubuf, size_t len)
{
	struct stdio_buf *buf = &stdio->input;

	/*
	 * we're waiting on user input (or for the file descriptor to be
	 * closed), don't want a hung task warning:
	 */
	do {
		wait_event_timeout(buf->wait, stdio_redirect_has_input(stdio),
				   sysctl_hung_task_timeout_secs * HZ / 2);
	} while (!stdio_redirect_has_input(stdio));

	if (stdio->done)
		return -1;

	spin_lock(&buf->lock);
	int ret = min(len, buf->buf.nr);
	buf->buf.nr -= ret;
	memcpy(ubuf, buf->buf.data, ret);
	memmove(buf->buf.data,
		buf->buf.data + ret,
		buf->buf.nr);
	spin_unlock(&buf->lock);

	wake_up(&buf->wait);
	return ret;
}

int bch2_stdio_redirect_readline(struct stdio_redirect *stdio, char *ubuf, size_t len)
{
	struct stdio_buf *buf = &stdio->input;
	size_t copied = 0;
	ssize_t ret = 0;
again:
	do {
		wait_event_timeout(buf->wait, stdio_redirect_has_input(stdio),
				   sysctl_hung_task_timeout_secs * HZ / 2);
	} while (!stdio_redirect_has_input(stdio));

	if (stdio->done) {
		ret = -1;
		goto out;
	}

	spin_lock(&buf->lock);
	size_t b = min(len, buf->buf.nr);
	char *n = memchr(buf->buf.data, '\n', b);
	if (n)
		b = min_t(size_t, b, n + 1 - buf->buf.data);
	buf->buf.nr -= b;
	memcpy(ubuf, buf->buf.data, b);
	memmove(buf->buf.data,
		buf->buf.data + b,
		buf->buf.nr);
	ubuf += b;
	len -= b;
	copied += b;
	spin_unlock(&buf->lock);

	wake_up(&buf->wait);

	if (!n && len)
		goto again;
out:
	return copied ?: ret;
}

__printf(3, 0)
static ssize_t bch2_darray_vprintf(darray_char *out, gfp_t gfp, const char *fmt, va_list args)
{
	ssize_t ret;

	do {
		va_list args2;
		size_t len;

		va_copy(args2, args);
		len = vsnprintf(out->data + out->nr, darray_room(*out), fmt, args2);
		va_end(args2);

		if (len + 1 <= darray_room(*out)) {
			out->nr += len;
			return len;
		}

		ret = darray_make_room_gfp(out, len + 1, gfp);
	} while (ret == 0);

	return ret;
}

ssize_t bch2_stdio_redirect_vprintf(struct stdio_redirect *stdio, bool nonblocking,
				    const char *fmt, va_list args)
{
	struct stdio_buf *buf = &stdio->output;
	unsigned long flags;
	ssize_t ret;

again:
	spin_lock_irqsave(&buf->lock, flags);
	ret = bch2_darray_vprintf(&buf->buf, GFP_NOWAIT, fmt, args);
	spin_unlock_irqrestore(&buf->lock, flags);

	if (ret < 0) {
		if (nonblocking)
			return -EAGAIN;

		ret = wait_event_interruptible(buf->wait,
				stdio_redirect_has_output_space(stdio));
		if (ret)
			return ret;
		goto again;
	}

	wake_up(&buf->wait);
	return ret;
}

ssize_t bch2_stdio_redirect_printf(struct stdio_redirect *stdio, bool nonblocking,
				const char *fmt, ...)
{
	va_list args;
	ssize_t ret;

	va_start(args, fmt);
	ret = bch2_stdio_redirect_vprintf(stdio, nonblocking, fmt, args);
	va_end(args);

	return ret;
}

#endif /* NO_BCACHEFS_FS */