1// SPDX-License-Identifier: GPL-2.0
2
3#include "bcachefs.h"
4#include "alloc_background.h"
5#include "alloc_foreground.h"
6#include "btree_iter.h"
7#include "btree_update.h"
8#include "btree_write_buffer.h"
9#include "buckets.h"
10#include "clock.h"
11#include "compress.h"
12#include "disk_groups.h"
13#include "errcode.h"
14#include "error.h"
15#include "inode.h"
16#include "move.h"
17#include "rebalance.h"
18#include "subvolume.h"
19#include "super-io.h"
20#include "trace.h"
21
22#include <linux/freezer.h>
23#include <linux/kthread.h>
24#include <linux/sched/cputime.h>
25
26#define REBALANCE_WORK_SCAN_OFFSET	(U64_MAX - 1)
27
28static const char * const bch2_rebalance_state_strs[] = {
29#define x(t) #t,
30	BCH_REBALANCE_STATES()
31	NULL
32#undef x
33};
34
35static int __bch2_set_rebalance_needs_scan(struct btree_trans *trans, u64 inum)
36{
37	struct btree_iter iter;
38	struct bkey_s_c k;
39	struct bkey_i_cookie *cookie;
40	u64 v;
41	int ret;
42
43	bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
44			     SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
45			     BTREE_ITER_INTENT);
46	k = bch2_btree_iter_peek_slot(&iter);
47	ret = bkey_err(k);
48	if (ret)
49		goto err;
50
51	v = k.k->type == KEY_TYPE_cookie
52		? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
53		: 0;
54
55	cookie = bch2_trans_kmalloc(trans, sizeof(*cookie));
56	ret = PTR_ERR_OR_ZERO(cookie);
57	if (ret)
58		goto err;
59
60	bkey_cookie_init(&cookie->k_i);
61	cookie->k.p = iter.pos;
62	cookie->v.cookie = cpu_to_le64(v + 1);
63
64	ret = bch2_trans_update(trans, &iter, &cookie->k_i, 0);
65err:
66	bch2_trans_iter_exit(trans, &iter);
67	return ret;
68}
69
70int bch2_set_rebalance_needs_scan(struct bch_fs *c, u64 inum)
71{
72	int ret = bch2_trans_do(c, NULL, NULL, BCH_TRANS_COMMIT_no_enospc|BCH_TRANS_COMMIT_lazy_rw,
73			    __bch2_set_rebalance_needs_scan(trans, inum));
74	rebalance_wakeup(c);
75	return ret;
76}
77
78int bch2_set_fs_needs_rebalance(struct bch_fs *c)
79{
80	return bch2_set_rebalance_needs_scan(c, 0);
81}
82
83static int bch2_clear_rebalance_needs_scan(struct btree_trans *trans, u64 inum, u64 cookie)
84{
85	struct btree_iter iter;
86	struct bkey_s_c k;
87	u64 v;
88	int ret;
89
90	bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
91			     SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
92			     BTREE_ITER_INTENT);
93	k = bch2_btree_iter_peek_slot(&iter);
94	ret = bkey_err(k);
95	if (ret)
96		goto err;
97
98	v = k.k->type == KEY_TYPE_cookie
99		? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
100		: 0;
101
102	if (v == cookie)
103		ret = bch2_btree_delete_at(trans, &iter, 0);
104err:
105	bch2_trans_iter_exit(trans, &iter);
106	return ret;
107}
108
109static struct bkey_s_c next_rebalance_entry(struct btree_trans *trans,
110					    struct btree_iter *work_iter)
111{
112	return !kthread_should_stop()
113		? bch2_btree_iter_peek(work_iter)
114		: bkey_s_c_null;
115}
116
117static int bch2_bkey_clear_needs_rebalance(struct btree_trans *trans,
118					   struct btree_iter *iter,
119					   struct bkey_s_c k)
120{
121	struct bkey_i *n = bch2_bkey_make_mut(trans, iter, &k, 0);
122	int ret = PTR_ERR_OR_ZERO(n);
123	if (ret)
124		return ret;
125
126	extent_entry_drop(bkey_i_to_s(n),
127			  (void *) bch2_bkey_rebalance_opts(bkey_i_to_s_c(n)));
128	return bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc);
129}
130
131static struct bkey_s_c next_rebalance_extent(struct btree_trans *trans,
132			struct bpos work_pos,
133			struct btree_iter *extent_iter,
134			struct data_update_opts *data_opts)
135{
136	struct bch_fs *c = trans->c;
137	struct bkey_s_c k;
138
139	bch2_trans_iter_exit(trans, extent_iter);
140	bch2_trans_iter_init(trans, extent_iter,
141			     work_pos.inode ? BTREE_ID_extents : BTREE_ID_reflink,
142			     work_pos,
143			     BTREE_ITER_ALL_SNAPSHOTS);
144	k = bch2_btree_iter_peek_slot(extent_iter);
145	if (bkey_err(k))
146		return k;
147
148	const struct bch_extent_rebalance *r = k.k ? bch2_bkey_rebalance_opts(k) : NULL;
149	if (!r) {
150		/* raced due to btree write buffer, nothing to do */
151		return bkey_s_c_null;
152	}
153
154	memset(data_opts, 0, sizeof(*data_opts));
155
156	data_opts->rewrite_ptrs		=
157		bch2_bkey_ptrs_need_rebalance(c, k, r->target, r->compression);
158	data_opts->target		= r->target;
159
160	if (!data_opts->rewrite_ptrs) {
161		/*
162		 * device we would want to write to offline? devices in target
163		 * changed?
164		 *
165		 * We'll now need a full scan before this extent is picked up
166		 * again:
167		 */
168		int ret = bch2_bkey_clear_needs_rebalance(trans, extent_iter, k);
169		if (ret)
170			return bkey_s_c_err(ret);
171		return bkey_s_c_null;
172	}
173
174	if (trace_rebalance_extent_enabled()) {
175		struct printbuf buf = PRINTBUF;
176
177		prt_str(&buf, "target=");
178		bch2_target_to_text(&buf, c, r->target);
179		prt_str(&buf, " compression=");
180		bch2_compression_opt_to_text(&buf, r->compression);
181		prt_str(&buf, " ");
182		bch2_bkey_val_to_text(&buf, c, k);
183
184		trace_rebalance_extent(c, buf.buf);
185		printbuf_exit(&buf);
186	}
187
188	return k;
189}
190
191noinline_for_stack
192static int do_rebalance_extent(struct moving_context *ctxt,
193			       struct bpos work_pos,
194			       struct btree_iter *extent_iter)
195{
196	struct btree_trans *trans = ctxt->trans;
197	struct bch_fs *c = trans->c;
198	struct bch_fs_rebalance *r = &trans->c->rebalance;
199	struct data_update_opts data_opts;
200	struct bch_io_opts io_opts;
201	struct bkey_s_c k;
202	struct bkey_buf sk;
203	int ret;
204
205	ctxt->stats = &r->work_stats;
206	r->state = BCH_REBALANCE_working;
207
208	bch2_bkey_buf_init(&sk);
209
210	ret = bkey_err(k = next_rebalance_extent(trans, work_pos,
211						 extent_iter, &data_opts));
212	if (ret || !k.k)
213		goto out;
214
215	ret = bch2_move_get_io_opts_one(trans, &io_opts, k);
216	if (ret)
217		goto out;
218
219	atomic64_add(k.k->size, &ctxt->stats->sectors_seen);
220
221	/*
222	 * The iterator gets unlocked by __bch2_read_extent - need to
223	 * save a copy of @k elsewhere:
224	 */
225	bch2_bkey_buf_reassemble(&sk, c, k);
226	k = bkey_i_to_s_c(sk.k);
227
228	ret = bch2_move_extent(ctxt, NULL, extent_iter, k, io_opts, data_opts);
229	if (ret) {
230		if (bch2_err_matches(ret, ENOMEM)) {
231			/* memory allocation failure, wait for some IO to finish */
232			bch2_move_ctxt_wait_for_io(ctxt);
233			ret = -BCH_ERR_transaction_restart_nested;
234		}
235
236		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
237			goto out;
238
239		/* skip it and continue, XXX signal failure */
240		ret = 0;
241	}
242out:
243	bch2_bkey_buf_exit(&sk, c);
244	return ret;
245}
246
247static bool rebalance_pred(struct bch_fs *c, void *arg,
248			   struct bkey_s_c k,
249			   struct bch_io_opts *io_opts,
250			   struct data_update_opts *data_opts)
251{
252	unsigned target, compression;
253
254	if (k.k->p.inode) {
255		target		= io_opts->background_target;
256		compression	= background_compression(*io_opts);
257	} else {
258		const struct bch_extent_rebalance *r = bch2_bkey_rebalance_opts(k);
259
260		target		= r ? r->target : io_opts->background_target;
261		compression	= r ? r->compression : background_compression(*io_opts);
262	}
263
264	data_opts->rewrite_ptrs		= bch2_bkey_ptrs_need_rebalance(c, k, target, compression);
265	data_opts->target		= target;
266	return data_opts->rewrite_ptrs != 0;
267}
268
269static int do_rebalance_scan(struct moving_context *ctxt, u64 inum, u64 cookie)
270{
271	struct btree_trans *trans = ctxt->trans;
272	struct bch_fs_rebalance *r = &trans->c->rebalance;
273	int ret;
274
275	bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
276	ctxt->stats = &r->scan_stats;
277
278	if (!inum) {
279		r->scan_start	= BBPOS_MIN;
280		r->scan_end	= BBPOS_MAX;
281	} else {
282		r->scan_start	= BBPOS(BTREE_ID_extents, POS(inum, 0));
283		r->scan_end	= BBPOS(BTREE_ID_extents, POS(inum, U64_MAX));
284	}
285
286	r->state = BCH_REBALANCE_scanning;
287
288	ret = __bch2_move_data(ctxt, r->scan_start, r->scan_end, rebalance_pred, NULL) ?:
289		commit_do(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
290			  bch2_clear_rebalance_needs_scan(trans, inum, cookie));
291
292	bch2_move_stats_exit(&r->scan_stats, trans->c);
293	return ret;
294}
295
296static void rebalance_wait(struct bch_fs *c)
297{
298	struct bch_fs_rebalance *r = &c->rebalance;
299	struct io_clock *clock = &c->io_clock[WRITE];
300	u64 now = atomic64_read(&clock->now);
301	u64 min_member_capacity = bch2_min_rw_member_capacity(c);
302
303	if (min_member_capacity == U64_MAX)
304		min_member_capacity = 128 * 2048;
305
306	r->wait_iotime_end		= now + (min_member_capacity >> 6);
307
308	if (r->state != BCH_REBALANCE_waiting) {
309		r->wait_iotime_start	= now;
310		r->wait_wallclock_start	= ktime_get_real_ns();
311		r->state		= BCH_REBALANCE_waiting;
312	}
313
314	bch2_kthread_io_clock_wait(clock, r->wait_iotime_end, MAX_SCHEDULE_TIMEOUT);
315}
316
317static int do_rebalance(struct moving_context *ctxt)
318{
319	struct btree_trans *trans = ctxt->trans;
320	struct bch_fs *c = trans->c;
321	struct bch_fs_rebalance *r = &c->rebalance;
322	struct btree_iter rebalance_work_iter, extent_iter = { NULL };
323	struct bkey_s_c k;
324	int ret = 0;
325
326	bch2_move_stats_init(&r->work_stats, "rebalance_work");
327	bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
328
329	bch2_trans_iter_init(trans, &rebalance_work_iter,
330			     BTREE_ID_rebalance_work, POS_MIN,
331			     BTREE_ITER_ALL_SNAPSHOTS);
332
333	while (!bch2_move_ratelimit(ctxt)) {
334		if (!r->enabled) {
335			bch2_moving_ctxt_flush_all(ctxt);
336			kthread_wait_freezable(r->enabled ||
337					       kthread_should_stop());
338		}
339
340		if (kthread_should_stop())
341			break;
342
343		bch2_trans_begin(trans);
344
345		ret = bkey_err(k = next_rebalance_entry(trans, &rebalance_work_iter));
346		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
347			continue;
348		if (ret || !k.k)
349			break;
350
351		ret = k.k->type == KEY_TYPE_cookie
352			? do_rebalance_scan(ctxt, k.k->p.inode,
353					    le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie))
354			: do_rebalance_extent(ctxt, k.k->p, &extent_iter);
355
356		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
357			continue;
358		if (ret)
359			break;
360
361		bch2_btree_iter_advance(&rebalance_work_iter);
362	}
363
364	bch2_trans_iter_exit(trans, &extent_iter);
365	bch2_trans_iter_exit(trans, &rebalance_work_iter);
366	bch2_move_stats_exit(&r->scan_stats, c);
367
368	if (!ret &&
369	    !kthread_should_stop() &&
370	    !atomic64_read(&r->work_stats.sectors_seen) &&
371	    !atomic64_read(&r->scan_stats.sectors_seen)) {
372		bch2_moving_ctxt_flush_all(ctxt);
373		bch2_trans_unlock_long(trans);
374		rebalance_wait(c);
375	}
376
377	if (!bch2_err_matches(ret, EROFS))
378		bch_err_fn(c, ret);
379	return ret;
380}
381
382static int bch2_rebalance_thread(void *arg)
383{
384	struct bch_fs *c = arg;
385	struct bch_fs_rebalance *r = &c->rebalance;
386	struct moving_context ctxt;
387
388	set_freezable();
389
390	bch2_moving_ctxt_init(&ctxt, c, NULL, &r->work_stats,
391			      writepoint_ptr(&c->rebalance_write_point),
392			      true);
393
394	while (!kthread_should_stop() && !do_rebalance(&ctxt))
395		;
396
397	bch2_moving_ctxt_exit(&ctxt);
398
399	return 0;
400}
401
402void bch2_rebalance_status_to_text(struct printbuf *out, struct bch_fs *c)
403{
404	struct bch_fs_rebalance *r = &c->rebalance;
405
406	prt_str(out, bch2_rebalance_state_strs[r->state]);
407	prt_newline(out);
408	printbuf_indent_add(out, 2);
409
410	switch (r->state) {
411	case BCH_REBALANCE_waiting: {
412		u64 now = atomic64_read(&c->io_clock[WRITE].now);
413
414		prt_str(out, "io wait duration:  ");
415		bch2_prt_human_readable_s64(out, (r->wait_iotime_end - r->wait_iotime_start) << 9);
416		prt_newline(out);
417
418		prt_str(out, "io wait remaining: ");
419		bch2_prt_human_readable_s64(out, (r->wait_iotime_end - now) << 9);
420		prt_newline(out);
421
422		prt_str(out, "duration waited:   ");
423		bch2_pr_time_units(out, ktime_get_real_ns() - r->wait_wallclock_start);
424		prt_newline(out);
425		break;
426	}
427	case BCH_REBALANCE_working:
428		bch2_move_stats_to_text(out, &r->work_stats);
429		break;
430	case BCH_REBALANCE_scanning:
431		bch2_move_stats_to_text(out, &r->scan_stats);
432		break;
433	}
434	prt_newline(out);
435	printbuf_indent_sub(out, 2);
436}
437
438void bch2_rebalance_stop(struct bch_fs *c)
439{
440	struct task_struct *p;
441
442	c->rebalance.pd.rate.rate = UINT_MAX;
443	bch2_ratelimit_reset(&c->rebalance.pd.rate);
444
445	p = rcu_dereference_protected(c->rebalance.thread, 1);
446	c->rebalance.thread = NULL;
447
448	if (p) {
449		/* for sychronizing with rebalance_wakeup() */
450		synchronize_rcu();
451
452		kthread_stop(p);
453		put_task_struct(p);
454	}
455}
456
457int bch2_rebalance_start(struct bch_fs *c)
458{
459	struct task_struct *p;
460	int ret;
461
462	if (c->rebalance.thread)
463		return 0;
464
465	if (c->opts.nochanges)
466		return 0;
467
468	p = kthread_create(bch2_rebalance_thread, c, "bch-rebalance/%s", c->name);
469	ret = PTR_ERR_OR_ZERO(p);
470	bch_err_msg(c, ret, "creating rebalance thread");
471	if (ret)
472		return ret;
473
474	get_task_struct(p);
475	rcu_assign_pointer(c->rebalance.thread, p);
476	wake_up_process(p);
477	return 0;
478}
479
480void bch2_fs_rebalance_init(struct bch_fs *c)
481{
482	bch2_pd_controller_init(&c->rebalance.pd);
483}
484