summaryrefslogtreecommitdiff
path: root/fs/bcachefs/rebalance.c
blob: 22d1017aa49b975756905a9a69ce8bcd82416ca3 (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
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
// SPDX-License-Identifier: GPL-2.0

#include "bcachefs.h"
#include "alloc_background.h"
#include "alloc_foreground.h"
#include "btree_iter.h"
#include "btree_update.h"
#include "btree_write_buffer.h"
#include "buckets.h"
#include "clock.h"
#include "compress.h"
#include "disk_groups.h"
#include "errcode.h"
#include "error.h"
#include "inode.h"
#include "move.h"
#include "rebalance.h"
#include "subvolume.h"
#include "super-io.h"
#include "trace.h"

#include <linux/freezer.h>
#include <linux/kthread.h>
#include <linux/sched/cputime.h>

#define REBALANCE_WORK_SCAN_OFFSET	(U64_MAX - 1)

static const char * const bch2_rebalance_state_strs[] = {
#define x(t) #t,
	BCH_REBALANCE_STATES()
	NULL
#undef x
};

static int __bch2_set_rebalance_needs_scan(struct btree_trans *trans, u64 inum)
{
	struct btree_iter iter;
	struct bkey_s_c k;
	struct bkey_i_cookie *cookie;
	u64 v;
	int ret;

	bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
			     SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
			     BTREE_ITER_INTENT);
	k = bch2_btree_iter_peek_slot(&iter);
	ret = bkey_err(k);
	if (ret)
		goto err;

	v = k.k->type == KEY_TYPE_cookie
		? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
		: 0;

	cookie = bch2_trans_kmalloc(trans, sizeof(*cookie));
	ret = PTR_ERR_OR_ZERO(cookie);
	if (ret)
		goto err;

	bkey_cookie_init(&cookie->k_i);
	cookie->k.p = iter.pos;
	cookie->v.cookie = cpu_to_le64(v + 1);

	ret = bch2_trans_update(trans, &iter, &cookie->k_i, 0);
err:
	bch2_trans_iter_exit(trans, &iter);
	return ret;
}

int bch2_set_rebalance_needs_scan(struct bch_fs *c, u64 inum)
{
	int ret = bch2_trans_do(c, NULL, NULL, BCH_TRANS_COMMIT_no_enospc|BCH_TRANS_COMMIT_lazy_rw,
			    __bch2_set_rebalance_needs_scan(trans, inum));
	rebalance_wakeup(c);
	return ret;
}

int bch2_set_fs_needs_rebalance(struct bch_fs *c)
{
	return bch2_set_rebalance_needs_scan(c, 0);
}

static int bch2_clear_rebalance_needs_scan(struct btree_trans *trans, u64 inum, u64 cookie)
{
	struct btree_iter iter;
	struct bkey_s_c k;
	u64 v;
	int ret;

	bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
			     SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
			     BTREE_ITER_INTENT);
	k = bch2_btree_iter_peek_slot(&iter);
	ret = bkey_err(k);
	if (ret)
		goto err;

	v = k.k->type == KEY_TYPE_cookie
		? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
		: 0;

	if (v == cookie)
		ret = bch2_btree_delete_at(trans, &iter, 0);
err:
	bch2_trans_iter_exit(trans, &iter);
	return ret;
}

static struct bkey_s_c next_rebalance_entry(struct btree_trans *trans,
					    struct btree_iter *work_iter)
{
	return !kthread_should_stop()
		? bch2_btree_iter_peek(work_iter)
		: bkey_s_c_null;
}

static int bch2_bkey_clear_needs_rebalance(struct btree_trans *trans,
					   struct btree_iter *iter,
					   struct bkey_s_c k)
{
	struct bkey_i *n = bch2_bkey_make_mut(trans, iter, &k, 0);
	int ret = PTR_ERR_OR_ZERO(n);
	if (ret)
		return ret;

	extent_entry_drop(bkey_i_to_s(n),
			  (void *) bch2_bkey_rebalance_opts(bkey_i_to_s_c(n)));
	return bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc);
}

static struct bkey_s_c next_rebalance_extent(struct btree_trans *trans,
			struct bpos work_pos,
			struct btree_iter *extent_iter,
			struct data_update_opts *data_opts)
{
	struct bch_fs *c = trans->c;
	struct bkey_s_c k;

	bch2_trans_iter_exit(trans, extent_iter);
	bch2_trans_iter_init(trans, extent_iter,
			     work_pos.inode ? BTREE_ID_extents : BTREE_ID_reflink,
			     work_pos,
			     BTREE_ITER_ALL_SNAPSHOTS);
	k = bch2_btree_iter_peek_slot(extent_iter);
	if (bkey_err(k))
		return k;

	const struct bch_extent_rebalance *r = k.k ? bch2_bkey_rebalance_opts(k) : NULL;
	if (!r) {
		/* raced due to btree write buffer, nothing to do */
		return bkey_s_c_null;
	}

	memset(data_opts, 0, sizeof(*data_opts));

	data_opts->rewrite_ptrs		=
		bch2_bkey_ptrs_need_rebalance(c, k, r->target, r->compression);
	data_opts->target		= r->target;

	if (!data_opts->rewrite_ptrs) {
		/*
		 * device we would want to write to offline? devices in target
		 * changed?
		 *
		 * We'll now need a full scan before this extent is picked up
		 * again:
		 */
		int ret = bch2_bkey_clear_needs_rebalance(trans, extent_iter, k);
		if (ret)
			return bkey_s_c_err(ret);
		return bkey_s_c_null;
	}

	if (trace_rebalance_extent_enabled()) {
		struct printbuf buf = PRINTBUF;

		prt_str(&buf, "target=");
		bch2_target_to_text(&buf, c, r->target);
		prt_str(&buf, " compression=");
		bch2_compression_opt_to_text(&buf, r->compression);
		prt_str(&buf, " ");
		bch2_bkey_val_to_text(&buf, c, k);

		trace_rebalance_extent(c, buf.buf);
		printbuf_exit(&buf);
	}

	return k;
}

noinline_for_stack
static int do_rebalance_extent(struct moving_context *ctxt,
			       struct bpos work_pos,
			       struct btree_iter *extent_iter)
{
	struct btree_trans *trans = ctxt->trans;
	struct bch_fs *c = trans->c;
	struct bch_fs_rebalance *r = &trans->c->rebalance;
	struct data_update_opts data_opts;
	struct bch_io_opts io_opts;
	struct bkey_s_c k;
	struct bkey_buf sk;
	int ret;

	ctxt->stats = &r->work_stats;
	r->state = BCH_REBALANCE_working;

	bch2_bkey_buf_init(&sk);

	ret = bkey_err(k = next_rebalance_extent(trans, work_pos,
						 extent_iter, &data_opts));
	if (ret || !k.k)
		goto out;

	ret = bch2_move_get_io_opts_one(trans, &io_opts, k);
	if (ret)
		goto out;

	atomic64_add(k.k->size, &ctxt->stats->sectors_seen);

	/*
	 * The iterator gets unlocked by __bch2_read_extent - need to
	 * save a copy of @k elsewhere:
	 */
	bch2_bkey_buf_reassemble(&sk, c, k);
	k = bkey_i_to_s_c(sk.k);

	ret = bch2_move_extent(ctxt, NULL, extent_iter, k, io_opts, data_opts);
	if (ret) {
		if (bch2_err_matches(ret, ENOMEM)) {
			/* memory allocation failure, wait for some IO to finish */
			bch2_move_ctxt_wait_for_io(ctxt);
			ret = -BCH_ERR_transaction_restart_nested;
		}

		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
			goto out;

		/* skip it and continue, XXX signal failure */
		ret = 0;
	}
out:
	bch2_bkey_buf_exit(&sk, c);
	return ret;
}

static bool rebalance_pred(struct bch_fs *c, void *arg,
			   struct bkey_s_c k,
			   struct bch_io_opts *io_opts,
			   struct data_update_opts *data_opts)
{
	unsigned target, compression;

	if (k.k->p.inode) {
		target		= io_opts->background_target;
		compression	= background_compression(*io_opts);
	} else {
		const struct bch_extent_rebalance *r = bch2_bkey_rebalance_opts(k);

		target		= r ? r->target : io_opts->background_target;
		compression	= r ? r->compression : background_compression(*io_opts);
	}

	data_opts->rewrite_ptrs		= bch2_bkey_ptrs_need_rebalance(c, k, target, compression);
	data_opts->target		= target;
	return data_opts->rewrite_ptrs != 0;
}

static int do_rebalance_scan(struct moving_context *ctxt, u64 inum, u64 cookie)
{
	struct btree_trans *trans = ctxt->trans;
	struct bch_fs_rebalance *r = &trans->c->rebalance;
	int ret;

	bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
	ctxt->stats = &r->scan_stats;

	if (!inum) {
		r->scan_start	= BBPOS_MIN;
		r->scan_end	= BBPOS_MAX;
	} else {
		r->scan_start	= BBPOS(BTREE_ID_extents, POS(inum, 0));
		r->scan_end	= BBPOS(BTREE_ID_extents, POS(inum, U64_MAX));
	}

	r->state = BCH_REBALANCE_scanning;

	ret = __bch2_move_data(ctxt, r->scan_start, r->scan_end, rebalance_pred, NULL) ?:
		commit_do(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
			  bch2_clear_rebalance_needs_scan(trans, inum, cookie));

	bch2_move_stats_exit(&r->scan_stats, trans->c);
	return ret;
}

static void rebalance_wait(struct bch_fs *c)
{
	struct bch_fs_rebalance *r = &c->rebalance;
	struct io_clock *clock = &c->io_clock[WRITE];
	u64 now = atomic64_read(&clock->now);
	u64 min_member_capacity = bch2_min_rw_member_capacity(c);

	if (min_member_capacity == U64_MAX)
		min_member_capacity = 128 * 2048;

	r->wait_iotime_end		= now + (min_member_capacity >> 6);

	if (r->state != BCH_REBALANCE_waiting) {
		r->wait_iotime_start	= now;
		r->wait_wallclock_start	= ktime_get_real_ns();
		r->state		= BCH_REBALANCE_waiting;
	}

	bch2_kthread_io_clock_wait(clock, r->wait_iotime_end, MAX_SCHEDULE_TIMEOUT);
}

static int do_rebalance(struct moving_context *ctxt)
{
	struct btree_trans *trans = ctxt->trans;
	struct bch_fs *c = trans->c;
	struct bch_fs_rebalance *r = &c->rebalance;
	struct btree_iter rebalance_work_iter, extent_iter = { NULL };
	struct bkey_s_c k;
	int ret = 0;

	bch2_move_stats_init(&r->work_stats, "rebalance_work");
	bch2_move_stats_init(&r->scan_stats, "rebalance_scan");

	bch2_trans_iter_init(trans, &rebalance_work_iter,
			     BTREE_ID_rebalance_work, POS_MIN,
			     BTREE_ITER_ALL_SNAPSHOTS);

	while (!bch2_move_ratelimit(ctxt)) {
		if (!r->enabled) {
			bch2_moving_ctxt_flush_all(ctxt);
			kthread_wait_freezable(r->enabled ||
					       kthread_should_stop());
		}

		if (kthread_should_stop())
			break;

		bch2_trans_begin(trans);

		ret = bkey_err(k = next_rebalance_entry(trans, &rebalance_work_iter));
		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
			continue;
		if (ret || !k.k)
			break;

		ret = k.k->type == KEY_TYPE_cookie
			? do_rebalance_scan(ctxt, k.k->p.inode,
					    le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie))
			: do_rebalance_extent(ctxt, k.k->p, &extent_iter);

		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
			continue;
		if (ret)
			break;

		bch2_btree_iter_advance(&rebalance_work_iter);
	}

	bch2_trans_iter_exit(trans, &extent_iter);
	bch2_trans_iter_exit(trans, &rebalance_work_iter);
	bch2_move_stats_exit(&r->scan_stats, c);

	if (!ret &&
	    !kthread_should_stop() &&
	    !atomic64_read(&r->work_stats.sectors_seen) &&
	    !atomic64_read(&r->scan_stats.sectors_seen)) {
		bch2_moving_ctxt_flush_all(ctxt);
		bch2_trans_unlock_long(trans);
		rebalance_wait(c);
	}

	if (!bch2_err_matches(ret, EROFS))
		bch_err_fn(c, ret);
	return ret;
}

static int bch2_rebalance_thread(void *arg)
{
	struct bch_fs *c = arg;
	struct bch_fs_rebalance *r = &c->rebalance;
	struct moving_context ctxt;

	set_freezable();

	bch2_moving_ctxt_init(&ctxt, c, NULL, &r->work_stats,
			      writepoint_ptr(&c->rebalance_write_point),
			      true);

	while (!kthread_should_stop() && !do_rebalance(&ctxt))
		;

	bch2_moving_ctxt_exit(&ctxt);

	return 0;
}

void bch2_rebalance_status_to_text(struct printbuf *out, struct bch_fs *c)
{
	struct bch_fs_rebalance *r = &c->rebalance;

	prt_str(out, bch2_rebalance_state_strs[r->state]);
	prt_newline(out);
	printbuf_indent_add(out, 2);

	switch (r->state) {
	case BCH_REBALANCE_waiting: {
		u64 now = atomic64_read(&c->io_clock[WRITE].now);

		prt_str(out, "io wait duration:  ");
		bch2_prt_human_readable_s64(out, r->wait_iotime_end - r->wait_iotime_start);
		prt_newline(out);

		prt_str(out, "io wait remaining: ");
		bch2_prt_human_readable_s64(out, r->wait_iotime_end - now);
		prt_newline(out);

		prt_str(out, "duration waited:   ");
		bch2_pr_time_units(out, ktime_get_real_ns() - r->wait_wallclock_start);
		prt_newline(out);
		break;
	}
	case BCH_REBALANCE_working:
		bch2_move_stats_to_text(out, &r->work_stats);
		break;
	case BCH_REBALANCE_scanning:
		bch2_move_stats_to_text(out, &r->scan_stats);
		break;
	}
	prt_newline(out);
	printbuf_indent_sub(out, 2);
}

void bch2_rebalance_stop(struct bch_fs *c)
{
	struct task_struct *p;

	c->rebalance.pd.rate.rate = UINT_MAX;
	bch2_ratelimit_reset(&c->rebalance.pd.rate);

	p = rcu_dereference_protected(c->rebalance.thread, 1);
	c->rebalance.thread = NULL;

	if (p) {
		/* for sychronizing with rebalance_wakeup() */
		synchronize_rcu();

		kthread_stop(p);
		put_task_struct(p);
	}
}

int bch2_rebalance_start(struct bch_fs *c)
{
	struct task_struct *p;
	int ret;

	if (c->rebalance.thread)
		return 0;

	if (c->opts.nochanges)
		return 0;

	p = kthread_create(bch2_rebalance_thread, c, "bch-rebalance/%s", c->name);
	ret = PTR_ERR_OR_ZERO(p);
	bch_err_msg(c, ret, "creating rebalance thread");
	if (ret)
		return ret;

	get_task_struct(p);
	rcu_assign_pointer(c->rebalance.thread, p);
	wake_up_process(p);
	return 0;
}

void bch2_fs_rebalance_init(struct bch_fs *c)
{
	bch2_pd_controller_init(&c->rebalance.pd);
}