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
28 static const char * const bch2_rebalance_state_strs[] = {
29 #define x(t) #t,
30 BCH_REBALANCE_STATES()
31 NULL
32 #undef x
33 };
34
35 static 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);
65 err:
66 bch2_trans_iter_exit(trans, &iter);
67 return ret;
68 }
69
70 int 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
78 int bch2_set_fs_needs_rebalance(struct bch_fs *c)
79 {
80 return bch2_set_rebalance_needs_scan(c, 0);
81 }
82
83 static 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);
104 err:
105 bch2_trans_iter_exit(trans, &iter);
106 return ret;
107 }
108
109 static 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
117 static 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
131 static 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
191 noinline_for_stack
192 static 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 }
242 out:
243 bch2_bkey_buf_exit(&sk, c);
244 return ret;
245 }
246
247 static 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
269 static 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
296 static 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
317 static 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_trans_begin(trans);
327
328 bch2_move_stats_init(&r->work_stats, "rebalance_work");
329 bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
330
331 bch2_trans_iter_init(trans, &rebalance_work_iter,
332 BTREE_ID_rebalance_work, POS_MIN,
333 BTREE_ITER_all_snapshots);
334
335 while (!bch2_move_ratelimit(ctxt)) {
336 if (!r->enabled) {
337 bch2_moving_ctxt_flush_all(ctxt);
338 kthread_wait_freezable(r->enabled ||
339 kthread_should_stop());
340 }
341
342 if (kthread_should_stop())
343 break;
344
345 bch2_trans_begin(trans);
346
347 ret = bkey_err(k = next_rebalance_entry(trans, &rebalance_work_iter));
348 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
349 continue;
350 if (ret || !k.k)
351 break;
352
353 ret = k.k->type == KEY_TYPE_cookie
354 ? do_rebalance_scan(ctxt, k.k->p.inode,
355 le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie))
356 : do_rebalance_extent(ctxt, k.k->p, &extent_iter);
357
358 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
359 continue;
360 if (ret)
361 break;
362
363 bch2_btree_iter_advance(&rebalance_work_iter);
364 }
365
366 bch2_trans_iter_exit(trans, &extent_iter);
367 bch2_trans_iter_exit(trans, &rebalance_work_iter);
368 bch2_move_stats_exit(&r->scan_stats, c);
369
370 if (!ret &&
371 !kthread_should_stop() &&
372 !atomic64_read(&r->work_stats.sectors_seen) &&
373 !atomic64_read(&r->scan_stats.sectors_seen)) {
374 bch2_moving_ctxt_flush_all(ctxt);
375 bch2_trans_unlock_long(trans);
376 rebalance_wait(c);
377 }
378
379 if (!bch2_err_matches(ret, EROFS))
380 bch_err_fn(c, ret);
381 return ret;
382 }
383
384 static int bch2_rebalance_thread(void *arg)
385 {
386 struct bch_fs *c = arg;
387 struct bch_fs_rebalance *r = &c->rebalance;
388 struct moving_context ctxt;
389
390 set_freezable();
391
392 bch2_moving_ctxt_init(&ctxt, c, NULL, &r->work_stats,
393 writepoint_ptr(&c->rebalance_write_point),
394 true);
395
396 while (!kthread_should_stop() && !do_rebalance(&ctxt))
397 ;
398
399 bch2_moving_ctxt_exit(&ctxt);
400
401 return 0;
402 }
403
404 void bch2_rebalance_status_to_text(struct printbuf *out, struct bch_fs *c)
405 {
406 struct bch_fs_rebalance *r = &c->rebalance;
407
408 prt_str(out, bch2_rebalance_state_strs[r->state]);
409 prt_newline(out);
410 printbuf_indent_add(out, 2);
411
412 switch (r->state) {
413 case BCH_REBALANCE_waiting: {
414 u64 now = atomic64_read(&c->io_clock[WRITE].now);
415
416 prt_str(out, "io wait duration: ");
417 bch2_prt_human_readable_s64(out, (r->wait_iotime_end - r->wait_iotime_start) << 9);
418 prt_newline(out);
419
420 prt_str(out, "io wait remaining: ");
421 bch2_prt_human_readable_s64(out, (r->wait_iotime_end - now) << 9);
422 prt_newline(out);
423
424 prt_str(out, "duration waited: ");
425 bch2_pr_time_units(out, ktime_get_real_ns() - r->wait_wallclock_start);
426 prt_newline(out);
427 break;
428 }
429 case BCH_REBALANCE_working:
430 bch2_move_stats_to_text(out, &r->work_stats);
431 break;
432 case BCH_REBALANCE_scanning:
433 bch2_move_stats_to_text(out, &r->scan_stats);
434 break;
435 }
436 prt_newline(out);
437 printbuf_indent_sub(out, 2);
438 }
439
440 void bch2_rebalance_stop(struct bch_fs *c)
441 {
442 struct task_struct *p;
443
444 c->rebalance.pd.rate.rate = UINT_MAX;
445 bch2_ratelimit_reset(&c->rebalance.pd.rate);
446
447 p = rcu_dereference_protected(c->rebalance.thread, 1);
448 c->rebalance.thread = NULL;
449
450 if (p) {
451 /* for sychronizing with rebalance_wakeup() */
452 synchronize_rcu();
453
454 kthread_stop(p);
455 put_task_struct(p);
456 }
457 }
458
459 int bch2_rebalance_start(struct bch_fs *c)
460 {
461 struct task_struct *p;
462 int ret;
463
464 if (c->rebalance.thread)
465 return 0;
466
467 if (c->opts.nochanges)
468 return 0;
469
470 p = kthread_create(bch2_rebalance_thread, c, "bch-rebalance/%s", c->name);
471 ret = PTR_ERR_OR_ZERO(p);
472 bch_err_msg(c, ret, "creating rebalance thread");
473 if (ret)
474 return ret;
475
476 get_task_struct(p);
477 rcu_assign_pointer(c->rebalance.thread, p);
478 wake_up_process(p);
479 return 0;
480 }
481
482 void bch2_fs_rebalance_init(struct bch_fs *c)
483 {
484 bch2_pd_controller_init(&c->rebalance.pd);
485 }
486
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