fs/bcachefs/rebalance.c

   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 "io_write.h"
  17 #include "move.h"
  18 #include "rebalance.h"
  19 #include "subvolume.h"
  20 #include "super-io.h"
  21 #include "trace.h"
  22
  23 #include <linux/freezer.h>
  24 #include <linux/kthread.h>
  25 #include <linux/sched/cputime.h>
  26
  27 #define REBALANCE_WORK_SCAN_OFFSET      (U64_MAX - 1)
  28
  29 static const char * const bch2_rebalance_state_strs[] = {
  30 #define x(t) #t,
  31         BCH_REBALANCE_STATES()
  32         NULL
  33 #undef x
  34 };
  35
  36 static int __bch2_set_rebalance_needs_scan(struct btree_trans *trans, u64 inum)
  37 {
  38         struct btree_iter iter;
  39         struct bkey_s_c k;
  40         struct bkey_i_cookie *cookie;
  41         u64 v;
  42         int ret;
  43
  44         bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
  45                              SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
  46                              BTREE_ITER_intent);
  47         k = bch2_btree_iter_peek_slot(&iter);
  48         ret = bkey_err(k);
  49         if (ret)
  50                 goto err;
  51
  52         v = k.k->type == KEY_TYPE_cookie
  53                 ? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
  54                 : 0;
  55
  56         cookie = bch2_trans_kmalloc(trans, sizeof(*cookie));
  57         ret = PTR_ERR_OR_ZERO(cookie);
  58         if (ret)
  59                 goto err;
  60
  61         bkey_cookie_init(&cookie->k_i);
  62         cookie->k.p = iter.pos;
  63         cookie->v.cookie = cpu_to_le64(v + 1);
  64
  65         ret = bch2_trans_update(trans, &iter, &cookie->k_i, 0);
  66 err:
  67         bch2_trans_iter_exit(trans, &iter);
  68         return ret;
  69 }
  70
  71 int bch2_set_rebalance_needs_scan(struct bch_fs *c, u64 inum)
  72 {
  73         int ret = bch2_trans_commit_do(c, NULL, NULL,
  74                                        BCH_TRANS_COMMIT_no_enospc|
  75                                        BCH_TRANS_COMMIT_lazy_rw,
  76                             __bch2_set_rebalance_needs_scan(trans, inum));
  77         rebalance_wakeup(c);
  78         return ret;
  79 }
  80
  81 int bch2_set_fs_needs_rebalance(struct bch_fs *c)
  82 {
  83         return bch2_set_rebalance_needs_scan(c, 0);
  84 }
  85
  86 static int bch2_clear_rebalance_needs_scan(struct btree_trans *trans, u64 inum, u64 cookie)
  87 {
  88         struct btree_iter iter;
  89         struct bkey_s_c k;
  90         u64 v;
  91         int ret;
  92
  93         bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
  94                              SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
  95                              BTREE_ITER_intent);
  96         k = bch2_btree_iter_peek_slot(&iter);
  97         ret = bkey_err(k);
  98         if (ret)
  99                 goto err;
 100
 101         v = k.k->type == KEY_TYPE_cookie
 102                 ? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
 103                 : 0;
 104
 105         if (v == cookie)
 106                 ret = bch2_btree_delete_at(trans, &iter, 0);
 107 err:
 108         bch2_trans_iter_exit(trans, &iter);
 109         return ret;
 110 }
 111
 112 static struct bkey_s_c next_rebalance_entry(struct btree_trans *trans,
 113                                             struct btree_iter *work_iter)
 114 {
 115         return !kthread_should_stop()
 116                 ? bch2_btree_iter_peek(work_iter)
 117                 : bkey_s_c_null;
 118 }
 119
 120 static int bch2_bkey_clear_needs_rebalance(struct btree_trans *trans,
 121                                            struct btree_iter *iter,
 122                                            struct bkey_s_c k)
 123 {
 124         struct bkey_i *n = bch2_bkey_make_mut(trans, iter, &k, 0);
 125         int ret = PTR_ERR_OR_ZERO(n);
 126         if (ret)
 127                 return ret;
 128
 129         extent_entry_drop(bkey_i_to_s(n),
 130                           (void *) bch2_bkey_rebalance_opts(bkey_i_to_s_c(n)));
 131         return bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc);
 132 }
 133
 134 static struct bkey_s_c next_rebalance_extent(struct btree_trans *trans,
 135                         struct bpos work_pos,
 136                         struct btree_iter *extent_iter,
 137                         struct data_update_opts *data_opts)
 138 {
 139         struct bch_fs *c = trans->c;
 140         struct bkey_s_c k;
 141
 142         bch2_trans_iter_exit(trans, extent_iter);
 143         bch2_trans_iter_init(trans, extent_iter,
 144                              work_pos.inode ? BTREE_ID_extents : BTREE_ID_reflink,
 145                              work_pos,
 146                              BTREE_ITER_all_snapshots);
 147         k = bch2_btree_iter_peek_slot(extent_iter);
 148         if (bkey_err(k))
 149                 return k;
 150
 151         const struct bch_extent_rebalance *r = k.k ? bch2_bkey_rebalance_opts(k) : NULL;
 152         if (!r) {
 153                 /* raced due to btree write buffer, nothing to do */
 154                 return bkey_s_c_null;
 155         }
 156
 157         memset(data_opts, 0, sizeof(*data_opts));
 158
 159         data_opts->rewrite_ptrs         =
 160                 bch2_bkey_ptrs_need_rebalance(c, k, r->target, r->compression);
 161         data_opts->target               = r->target;
 162         data_opts->write_flags          |= BCH_WRITE_ONLY_SPECIFIED_DEVS;
 163
 164         if (!data_opts->rewrite_ptrs) {
 165                 /*
 166                  * device we would want to write to offline? devices in target
 167                  * changed?
 168                  *
 169                  * We'll now need a full scan before this extent is picked up
 170                  * again:
 171                  */
 172                 int ret = bch2_bkey_clear_needs_rebalance(trans, extent_iter, k);
 173                 if (ret)
 174                         return bkey_s_c_err(ret);
 175                 return bkey_s_c_null;
 176         }
 177
 178         if (trace_rebalance_extent_enabled()) {
 179                 struct printbuf buf = PRINTBUF;
 180
 181                 prt_str(&buf, "target=");
 182                 bch2_target_to_text(&buf, c, r->target);
 183                 prt_str(&buf, " compression=");
 184                 bch2_compression_opt_to_text(&buf, r->compression);
 185                 prt_str(&buf, " ");
 186                 bch2_bkey_val_to_text(&buf, c, k);
 187
 188                 trace_rebalance_extent(c, buf.buf);
 189                 printbuf_exit(&buf);
 190         }
 191
 192         return k;
 193 }
 194
 195 noinline_for_stack
 196 static int do_rebalance_extent(struct moving_context *ctxt,
 197                                struct bpos work_pos,
 198                                struct btree_iter *extent_iter)
 199 {
 200         struct btree_trans *trans = ctxt->trans;
 201         struct bch_fs *c = trans->c;
 202         struct bch_fs_rebalance *r = &trans->c->rebalance;
 203         struct data_update_opts data_opts;
 204         struct bch_io_opts io_opts;
 205         struct bkey_s_c k;
 206         struct bkey_buf sk;
 207         int ret;
 208
 209         ctxt->stats = &r->work_stats;
 210         r->state = BCH_REBALANCE_working;
 211
 212         bch2_bkey_buf_init(&sk);
 213
 214         ret = bkey_err(k = next_rebalance_extent(trans, work_pos,
 215                                                  extent_iter, &data_opts));
 216         if (ret || !k.k)
 217                 goto out;
 218
 219         ret = bch2_move_get_io_opts_one(trans, &io_opts, k);
 220         if (ret)
 221                 goto out;
 222
 223         atomic64_add(k.k->size, &ctxt->stats->sectors_seen);
 224
 225         /*
 226          * The iterator gets unlocked by __bch2_read_extent - need to
 227          * save a copy of @k elsewhere:
 228          */
 229         bch2_bkey_buf_reassemble(&sk, c, k);
 230         k = bkey_i_to_s_c(sk.k);
 231
 232         ret = bch2_move_extent(ctxt, NULL, extent_iter, k, io_opts, data_opts);
 233         if (ret) {
 234                 if (bch2_err_matches(ret, ENOMEM)) {
 235                         /* memory allocation failure, wait for some IO to finish */
 236                         bch2_move_ctxt_wait_for_io(ctxt);
 237                         ret = -BCH_ERR_transaction_restart_nested;
 238                 }
 239
 240                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 241                         goto out;
 242
 243                 /* skip it and continue, XXX signal failure */
 244                 ret = 0;
 245         }
 246 out:
 247         bch2_bkey_buf_exit(&sk, c);
 248         return ret;
 249 }
 250
 251 static bool rebalance_pred(struct bch_fs *c, void *arg,
 252                            struct bkey_s_c k,
 253                            struct bch_io_opts *io_opts,
 254                            struct data_update_opts *data_opts)
 255 {
 256         unsigned target, compression;
 257
 258         if (k.k->p.inode) {
 259                 target          = io_opts->background_target;
 260                 compression     = background_compression(*io_opts);
 261         } else {
 262                 const struct bch_extent_rebalance *r = bch2_bkey_rebalance_opts(k);
 263
 264                 target          = r ? r->target : io_opts->background_target;
 265                 compression     = r ? r->compression : background_compression(*io_opts);
 266         }
 267
 268         data_opts->rewrite_ptrs         = bch2_bkey_ptrs_need_rebalance(c, k, target, compression);
 269         data_opts->target               = target;
 270         data_opts->write_flags          |= BCH_WRITE_ONLY_SPECIFIED_DEVS;
 271         return data_opts->rewrite_ptrs != 0;
 272 }
 273
 274 static int do_rebalance_scan(struct moving_context *ctxt, u64 inum, u64 cookie)
 275 {
 276         struct btree_trans *trans = ctxt->trans;
 277         struct bch_fs_rebalance *r = &trans->c->rebalance;
 278         int ret;
 279
 280         bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
 281         ctxt->stats = &r->scan_stats;
 282
 283         if (!inum) {
 284                 r->scan_start   = BBPOS_MIN;
 285                 r->scan_end     = BBPOS_MAX;
 286         } else {
 287                 r->scan_start   = BBPOS(BTREE_ID_extents, POS(inum, 0));
 288                 r->scan_end     = BBPOS(BTREE_ID_extents, POS(inum, U64_MAX));
 289         }
 290
 291         r->state = BCH_REBALANCE_scanning;
 292
 293         ret = __bch2_move_data(ctxt, r->scan_start, r->scan_end, rebalance_pred, NULL) ?:
 294                 commit_do(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
 295                           bch2_clear_rebalance_needs_scan(trans, inum, cookie));
 296
 297         bch2_move_stats_exit(&r->scan_stats, trans->c);
 298         return ret;
 299 }
 300
 301 static void rebalance_wait(struct bch_fs *c)
 302 {
 303         struct bch_fs_rebalance *r = &c->rebalance;
 304         struct io_clock *clock = &c->io_clock[WRITE];
 305         u64 now = atomic64_read(&clock->now);
 306         u64 min_member_capacity = bch2_min_rw_member_capacity(c);
 307
 308         if (min_member_capacity == U64_MAX)
 309                 min_member_capacity = 128 * 2048;
 310
 311         r->wait_iotime_end              = now + (min_member_capacity >> 6);
 312
 313         if (r->state != BCH_REBALANCE_waiting) {
 314                 r->wait_iotime_start    = now;
 315                 r->wait_wallclock_start = ktime_get_real_ns();
 316                 r->state                = BCH_REBALANCE_waiting;
 317         }
 318
 319         bch2_kthread_io_clock_wait(clock, r->wait_iotime_end, MAX_SCHEDULE_TIMEOUT);
 320 }
 321
 322 static int do_rebalance(struct moving_context *ctxt)
 323 {
 324         struct btree_trans *trans = ctxt->trans;
 325         struct bch_fs *c = trans->c;
 326         struct bch_fs_rebalance *r = &c->rebalance;
 327         struct btree_iter rebalance_work_iter, extent_iter = { NULL };
 328         struct bkey_s_c k;
 329         int ret = 0;
 330
 331         bch2_trans_begin(trans);
 332
 333         bch2_move_stats_init(&r->work_stats, "rebalance_work");
 334         bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
 335
 336         bch2_trans_iter_init(trans, &rebalance_work_iter,
 337                              BTREE_ID_rebalance_work, POS_MIN,
 338                              BTREE_ITER_all_snapshots);
 339
 340         while (!bch2_move_ratelimit(ctxt)) {
 341                 if (!r->enabled) {
 342                         bch2_moving_ctxt_flush_all(ctxt);
 343                         kthread_wait_freezable(r->enabled ||
 344                                                kthread_should_stop());
 345                 }
 346
 347                 if (kthread_should_stop())
 348                         break;
 349
 350                 bch2_trans_begin(trans);
 351
 352                 ret = bkey_err(k = next_rebalance_entry(trans, &rebalance_work_iter));
 353                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 354                         continue;
 355                 if (ret || !k.k)
 356                         break;
 357
 358                 ret = k.k->type == KEY_TYPE_cookie
 359                         ? do_rebalance_scan(ctxt, k.k->p.inode,
 360                                             le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie))
 361                         : do_rebalance_extent(ctxt, k.k->p, &extent_iter);
 362
 363                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 364                         continue;
 365                 if (ret)
 366                         break;
 367
 368                 bch2_btree_iter_advance(&rebalance_work_iter);
 369         }
 370
 371         bch2_trans_iter_exit(trans, &extent_iter);
 372         bch2_trans_iter_exit(trans, &rebalance_work_iter);
 373         bch2_move_stats_exit(&r->scan_stats, c);
 374
 375         if (!ret &&
 376             !kthread_should_stop() &&
 377             !atomic64_read(&r->work_stats.sectors_seen) &&
 378             !atomic64_read(&r->scan_stats.sectors_seen)) {
 379                 bch2_moving_ctxt_flush_all(ctxt);
 380                 bch2_trans_unlock_long(trans);
 381                 rebalance_wait(c);
 382         }
 383
 384         if (!bch2_err_matches(ret, EROFS))
 385                 bch_err_fn(c, ret);
 386         return ret;
 387 }
 388
 389 static int bch2_rebalance_thread(void *arg)
 390 {
 391         struct bch_fs *c = arg;
 392         struct bch_fs_rebalance *r = &c->rebalance;
 393         struct moving_context ctxt;
 394
 395         set_freezable();
 396
 397         bch2_moving_ctxt_init(&ctxt, c, NULL, &r->work_stats,
 398                               writepoint_ptr(&c->rebalance_write_point),
 399                               true);
 400
 401         while (!kthread_should_stop() && !do_rebalance(&ctxt))
 402                 ;
 403
 404         bch2_moving_ctxt_exit(&ctxt);
 405
 406         return 0;
 407 }
 408
 409 void bch2_rebalance_status_to_text(struct printbuf *out, struct bch_fs *c)
 410 {
 411         struct bch_fs_rebalance *r = &c->rebalance;
 412
 413         prt_str(out, bch2_rebalance_state_strs[r->state]);
 414         prt_newline(out);
 415         printbuf_indent_add(out, 2);
 416
 417         switch (r->state) {
 418         case BCH_REBALANCE_waiting: {
 419                 u64 now = atomic64_read(&c->io_clock[WRITE].now);
 420
 421                 prt_str(out, "io wait duration:  ");
 422                 bch2_prt_human_readable_s64(out, (r->wait_iotime_end - r->wait_iotime_start) << 9);
 423                 prt_newline(out);
 424
 425                 prt_str(out, "io wait remaining: ");
 426                 bch2_prt_human_readable_s64(out, (r->wait_iotime_end - now) << 9);
 427                 prt_newline(out);
 428
 429                 prt_str(out, "duration waited:   ");
 430                 bch2_pr_time_units(out, ktime_get_real_ns() - r->wait_wallclock_start);
 431                 prt_newline(out);
 432                 break;
 433         }
 434         case BCH_REBALANCE_working:
 435                 bch2_move_stats_to_text(out, &r->work_stats);
 436                 break;
 437         case BCH_REBALANCE_scanning:
 438                 bch2_move_stats_to_text(out, &r->scan_stats);
 439                 break;
 440         }
 441         prt_newline(out);
 442         printbuf_indent_sub(out, 2);
 443 }
 444
 445 void bch2_rebalance_stop(struct bch_fs *c)
 446 {
 447         struct task_struct *p;
 448
 449         c->rebalance.pd.rate.rate = UINT_MAX;
 450         bch2_ratelimit_reset(&c->rebalance.pd.rate);
 451
 452         p = rcu_dereference_protected(c->rebalance.thread, 1);
 453         c->rebalance.thread = NULL;
 454
 455         if (p) {
 456                 /* for sychronizing with rebalance_wakeup() */
 457                 synchronize_rcu();
 458
 459                 kthread_stop(p);
 460                 put_task_struct(p);
 461         }
 462 }
 463
 464 int bch2_rebalance_start(struct bch_fs *c)
 465 {
 466         struct task_struct *p;
 467         int ret;
 468
 469         if (c->rebalance.thread)
 470                 return 0;
 471
 472         if (c->opts.nochanges)
 473                 return 0;
 474
 475         p = kthread_create(bch2_rebalance_thread, c, "bch-rebalance/%s", c->name);
 476         ret = PTR_ERR_OR_ZERO(p);
 477         bch_err_msg(c, ret, "creating rebalance thread");
 478         if (ret)
 479                 return ret;
 480
 481         get_task_struct(p);
 482         rcu_assign_pointer(c->rebalance.thread, p);
 483         wake_up_process(p);
 484         return 0;
 485 }
 486
 487 void bch2_fs_rebalance_init(struct bch_fs *c)
 488 {
 489         bch2_pd_controller_init(&c->rebalance.pd);
 490 }