git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/rebalance.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "bcachefs.h"
   4 #include "alloc_foreground.h"
   5 #include "btree_iter.h"
   6 #include "btree_update.h"
   7 #include "btree_write_buffer.h"
   8 #include "buckets.h"
   9 #include "clock.h"
  10 #include "compress.h"
  11 #include "disk_groups.h"
  12 #include "errcode.h"
  13 #include "error.h"
  14 #include "inode.h"
  15 #include "move.h"
  16 #include "rebalance.h"
  17 #include "subvolume.h"
  18 #include "super-io.h"
  19 #include "trace.h"
  20
  21 #include <linux/freezer.h>
  22 #include <linux/kthread.h>
  23 #include <linux/sched/cputime.h>
  24
  25 #define REBALANCE_WORK_SCAN_OFFSET      (U64_MAX - 1)
  26
  27 static const char * const bch2_rebalance_state_strs[] = {
  28 #define x(t) #t,
  29         BCH_REBALANCE_STATES()
  30         NULL
  31 #undef x
  32 };
  33
  34 static int __bch2_set_rebalance_needs_scan(struct btree_trans *trans, u64 inum)
  35 {
  36         struct btree_iter iter;
  37         struct bkey_s_c k;
  38         struct bkey_i_cookie *cookie;
  39         u64 v;
  40         int ret;
  41
  42         bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
  43                              SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
  44                              BTREE_ITER_INTENT);
  45         k = bch2_btree_iter_peek_slot(&iter);
  46         ret = bkey_err(k);
  47         if (ret)
  48                 goto err;
  49
  50         v = k.k->type == KEY_TYPE_cookie
  51                 ? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
  52                 : 0;
  53
  54         cookie = bch2_trans_kmalloc(trans, sizeof(*cookie));
  55         ret = PTR_ERR_OR_ZERO(cookie);
  56         if (ret)
  57                 goto err;
  58
  59         bkey_cookie_init(&cookie->k_i);
  60         cookie->k.p = iter.pos;
  61         cookie->v.cookie = cpu_to_le64(v + 1);
  62
  63         ret = bch2_trans_update(trans, &iter, &cookie->k_i, 0);
  64 err:
  65         bch2_trans_iter_exit(trans, &iter);
  66         return ret;
  67 }
  68
  69 int bch2_set_rebalance_needs_scan(struct bch_fs *c, u64 inum)
  70 {
  71         int ret = bch2_trans_do(c, NULL, NULL, BTREE_INSERT_NOFAIL|BTREE_INSERT_LAZY_RW,
  72                             __bch2_set_rebalance_needs_scan(trans, inum));
  73         rebalance_wakeup(c);
  74         return ret;
  75 }
  76
  77 int bch2_set_fs_needs_rebalance(struct bch_fs *c)
  78 {
  79         return bch2_set_rebalance_needs_scan(c, 0);
  80 }
  81
  82 static int bch2_clear_rebalance_needs_scan(struct btree_trans *trans, u64 inum, u64 cookie)
  83 {
  84         struct btree_iter iter;
  85         struct bkey_s_c k;
  86         u64 v;
  87         int ret;
  88
  89         bch2_trans_iter_init(trans, &iter, BTREE_ID_rebalance_work,
  90                              SPOS(inum, REBALANCE_WORK_SCAN_OFFSET, U32_MAX),
  91                              BTREE_ITER_INTENT);
  92         k = bch2_btree_iter_peek_slot(&iter);
  93         ret = bkey_err(k);
  94         if (ret)
  95                 goto err;
  96
  97         v = k.k->type == KEY_TYPE_cookie
  98                 ? le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie)
  99                 : 0;
 100
 101         if (v == cookie)
 102                 ret = bch2_btree_delete_at(trans, &iter, 0);
 103 err:
 104         bch2_trans_iter_exit(trans, &iter);
 105         return ret;
 106 }
 107
 108 static struct bkey_s_c next_rebalance_entry(struct btree_trans *trans,
 109                                             struct btree_iter *work_iter)
 110 {
 111         return !kthread_should_stop()
 112                 ? bch2_btree_iter_peek(work_iter)
 113                 : bkey_s_c_null;
 114 }
 115
 116 static int bch2_bkey_clear_needs_rebalance(struct btree_trans *trans,
 117                                            struct btree_iter *iter,
 118                                            struct bkey_s_c k)
 119 {
 120         struct bkey_i *n = bch2_bkey_make_mut(trans, iter, &k, 0);
 121         int ret = PTR_ERR_OR_ZERO(n);
 122         if (ret)
 123                 return ret;
 124
 125         extent_entry_drop(bkey_i_to_s(n),
 126                           (void *) bch2_bkey_rebalance_opts(bkey_i_to_s_c(n)));
 127         return bch2_trans_commit(trans, NULL, NULL, BTREE_INSERT_NOFAIL);
 128 }
 129
 130 static struct bkey_s_c next_rebalance_extent(struct btree_trans *trans,
 131                         struct bpos work_pos,
 132                         struct btree_iter *extent_iter,
 133                         struct data_update_opts *data_opts)
 134 {
 135         struct bch_fs *c = trans->c;
 136         struct bkey_s_c k;
 137
 138         bch2_trans_iter_exit(trans, extent_iter);
 139         bch2_trans_iter_init(trans, extent_iter,
 140                              work_pos.inode ? BTREE_ID_extents : BTREE_ID_reflink,
 141                              work_pos,
 142                              BTREE_ITER_ALL_SNAPSHOTS);
 143         k = bch2_btree_iter_peek_slot(extent_iter);
 144         if (bkey_err(k))
 145                 return k;
 146
 147         const struct bch_extent_rebalance *r = k.k ? bch2_bkey_rebalance_opts(k) : NULL;
 148         if (!r) {
 149                 /* raced due to btree write buffer, nothing to do */
 150                 return bkey_s_c_null;
 151         }
 152
 153         memset(data_opts, 0, sizeof(*data_opts));
 154
 155         data_opts->rewrite_ptrs         =
 156                 bch2_bkey_ptrs_need_rebalance(c, k, r->target, r->compression);
 157         data_opts->target               = r->target;
 158
 159         if (!data_opts->rewrite_ptrs) {
 160                 /*
 161                  * device we would want to write to offline? devices in target
 162                  * changed?
 163                  *
 164                  * We'll now need a full scan before this extent is picked up
 165                  * again:
 166                  */
 167                 int ret = bch2_bkey_clear_needs_rebalance(trans, extent_iter, k);
 168                 if (ret)
 169                         return bkey_s_c_err(ret);
 170                 return bkey_s_c_null;
 171         }
 172
 173         return k;
 174 }
 175
 176 noinline_for_stack
 177 static int do_rebalance_extent(struct moving_context *ctxt,
 178                                struct bpos work_pos,
 179                                struct btree_iter *extent_iter)
 180 {
 181         struct btree_trans *trans = ctxt->trans;
 182         struct bch_fs *c = trans->c;
 183         struct bch_fs_rebalance *r = &trans->c->rebalance;
 184         struct data_update_opts data_opts;
 185         struct bch_io_opts io_opts;
 186         struct bkey_s_c k;
 187         struct bkey_buf sk;
 188         int ret;
 189
 190         ctxt->stats = &r->work_stats;
 191         r->state = BCH_REBALANCE_working;
 192
 193         bch2_bkey_buf_init(&sk);
 194
 195         ret = bkey_err(k = next_rebalance_extent(trans, work_pos,
 196                                                  extent_iter, &data_opts));
 197         if (ret || !k.k)
 198                 goto out;
 199
 200         ret = bch2_move_get_io_opts_one(trans, &io_opts, k);
 201         if (ret)
 202                 goto out;
 203
 204         atomic64_add(k.k->size, &ctxt->stats->sectors_seen);
 205
 206         /*
 207          * The iterator gets unlocked by __bch2_read_extent - need to
 208          * save a copy of @k elsewhere:
 209          */
 210         bch2_bkey_buf_reassemble(&sk, c, k);
 211         k = bkey_i_to_s_c(sk.k);
 212
 213         ret = bch2_move_extent(ctxt, NULL, extent_iter, k, io_opts, data_opts);
 214         if (ret) {
 215                 if (bch2_err_matches(ret, ENOMEM)) {
 216                         /* memory allocation failure, wait for some IO to finish */
 217                         bch2_move_ctxt_wait_for_io(ctxt);
 218                         ret = -BCH_ERR_transaction_restart_nested;
 219                 }
 220
 221                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 222                         goto out;
 223
 224                 /* skip it and continue, XXX signal failure */
 225                 ret = 0;
 226         }
 227 out:
 228         bch2_bkey_buf_exit(&sk, c);
 229         return ret;
 230 }
 231
 232 static bool rebalance_pred(struct bch_fs *c, void *arg,
 233                            struct bkey_s_c k,
 234                            struct bch_io_opts *io_opts,
 235                            struct data_update_opts *data_opts)
 236 {
 237         unsigned target, compression;
 238
 239         if (k.k->p.inode) {
 240                 target          = io_opts->background_target;
 241                 compression     = io_opts->background_compression ?: io_opts->compression;
 242         } else {
 243                 const struct bch_extent_rebalance *r = bch2_bkey_rebalance_opts(k);
 244
 245                 target          = r ? r->target : io_opts->background_target;
 246                 compression     = r ? r->compression :
 247                         (io_opts->background_compression ?: io_opts->compression);
 248         }
 249
 250         data_opts->rewrite_ptrs         = bch2_bkey_ptrs_need_rebalance(c, k, target, compression);
 251         data_opts->target               = target;
 252         return data_opts->rewrite_ptrs != 0;
 253 }
 254
 255 static int do_rebalance_scan(struct moving_context *ctxt, u64 inum, u64 cookie)
 256 {
 257         struct btree_trans *trans = ctxt->trans;
 258         struct bch_fs_rebalance *r = &trans->c->rebalance;
 259         int ret;
 260
 261         bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
 262         ctxt->stats = &r->scan_stats;
 263
 264         if (!inum) {
 265                 r->scan_start   = BBPOS_MIN;
 266                 r->scan_end     = BBPOS_MAX;
 267         } else {
 268                 r->scan_start   = BBPOS(BTREE_ID_extents, POS(inum, 0));
 269                 r->scan_end     = BBPOS(BTREE_ID_extents, POS(inum, U64_MAX));
 270         }
 271
 272         r->state = BCH_REBALANCE_scanning;
 273
 274         ret = __bch2_move_data(ctxt, r->scan_start, r->scan_end, rebalance_pred, NULL) ?:
 275                 commit_do(trans, NULL, NULL, BTREE_INSERT_NOFAIL,
 276                           bch2_clear_rebalance_needs_scan(trans, inum, cookie));
 277
 278         bch2_move_stats_exit(&r->scan_stats, trans->c);
 279         return ret;
 280 }
 281
 282 static void rebalance_wait(struct bch_fs *c)
 283 {
 284         struct bch_fs_rebalance *r = &c->rebalance;
 285         struct bch_dev *ca;
 286         struct io_clock *clock = &c->io_clock[WRITE];
 287         u64 now = atomic64_read(&clock->now);
 288         u64 min_member_capacity = 128 * 2048;
 289         unsigned i;
 290
 291         for_each_rw_member(ca, c, i)
 292                 min_member_capacity = min(min_member_capacity,
 293                                           ca->mi.nbuckets * ca->mi.bucket_size);
 294
 295         r->wait_iotime_end              = now + (min_member_capacity >> 6);
 296
 297         if (r->state != BCH_REBALANCE_waiting) {
 298                 r->wait_iotime_start    = now;
 299                 r->wait_wallclock_start = ktime_get_real_ns();
 300                 r->state                = BCH_REBALANCE_waiting;
 301         }
 302
 303         bch2_kthread_io_clock_wait(clock, r->wait_iotime_end, MAX_SCHEDULE_TIMEOUT);
 304 }
 305
 306 static int do_rebalance(struct moving_context *ctxt)
 307 {
 308         struct btree_trans *trans = ctxt->trans;
 309         struct bch_fs *c = trans->c;
 310         struct bch_fs_rebalance *r = &c->rebalance;
 311         struct btree_iter rebalance_work_iter, extent_iter = { NULL };
 312         struct bkey_s_c k;
 313         int ret = 0;
 314
 315         bch2_move_stats_init(&r->work_stats, "rebalance_work");
 316         bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
 317
 318         bch2_trans_iter_init(trans, &rebalance_work_iter,
 319                              BTREE_ID_rebalance_work, POS_MIN,
 320                              BTREE_ITER_ALL_SNAPSHOTS);
 321
 322         while (!bch2_move_ratelimit(ctxt) &&
 323                !kthread_wait_freezable(r->enabled)) {
 324                 bch2_trans_begin(trans);
 325
 326                 ret = bkey_err(k = next_rebalance_entry(trans, &rebalance_work_iter));
 327                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 328                         continue;
 329                 if (ret || !k.k)
 330                         break;
 331
 332                 ret = k.k->type == KEY_TYPE_cookie
 333                         ? do_rebalance_scan(ctxt, k.k->p.inode,
 334                                             le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie))
 335                         : do_rebalance_extent(ctxt, k.k->p, &extent_iter);
 336
 337                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 338                         continue;
 339                 if (ret)
 340                         break;
 341
 342                 bch2_btree_iter_advance(&rebalance_work_iter);
 343         }
 344
 345         bch2_trans_iter_exit(trans, &extent_iter);
 346         bch2_trans_iter_exit(trans, &rebalance_work_iter);
 347         bch2_move_stats_exit(&r->scan_stats, c);
 348
 349         if (!ret &&
 350             !kthread_should_stop() &&
 351             !atomic64_read(&r->work_stats.sectors_seen) &&
 352             !atomic64_read(&r->scan_stats.sectors_seen)) {
 353                 bch2_trans_unlock(trans);
 354                 rebalance_wait(c);
 355         }
 356
 357         bch_err_fn(c, ret);
 358         return ret;
 359 }
 360
 361 static int bch2_rebalance_thread(void *arg)
 362 {
 363         struct bch_fs *c = arg;
 364         struct bch_fs_rebalance *r = &c->rebalance;
 365         struct moving_context ctxt;
 366         int ret;
 367
 368         set_freezable();
 369
 370         bch2_moving_ctxt_init(&ctxt, c, NULL, &r->work_stats,
 371                               writepoint_ptr(&c->rebalance_write_point),
 372                               true);
 373
 374         while (!kthread_should_stop() &&
 375                !(ret = do_rebalance(&ctxt)))
 376                 ;
 377
 378         bch2_moving_ctxt_exit(&ctxt);
 379
 380         return 0;
 381 }
 382
 383 void bch2_rebalance_status_to_text(struct printbuf *out, struct bch_fs *c)
 384 {
 385         struct bch_fs_rebalance *r = &c->rebalance;
 386
 387         prt_str(out, bch2_rebalance_state_strs[r->state]);
 388         prt_newline(out);
 389         printbuf_indent_add(out, 2);
 390
 391         switch (r->state) {
 392         case BCH_REBALANCE_waiting: {
 393                 u64 now = atomic64_read(&c->io_clock[WRITE].now);
 394
 395                 prt_str(out, "io wait duration:  ");
 396                 bch2_prt_human_readable_s64(out, r->wait_iotime_end - r->wait_iotime_start);
 397                 prt_newline(out);
 398
 399                 prt_str(out, "io wait remaining: ");
 400                 bch2_prt_human_readable_s64(out, r->wait_iotime_end - now);
 401                 prt_newline(out);
 402
 403                 prt_str(out, "duration waited:   ");
 404                 bch2_pr_time_units(out, ktime_get_real_ns() - r->wait_wallclock_start);
 405                 prt_newline(out);
 406                 break;
 407         }
 408         case BCH_REBALANCE_working:
 409                 bch2_move_stats_to_text(out, &r->work_stats);
 410                 break;
 411         case BCH_REBALANCE_scanning:
 412                 bch2_move_stats_to_text(out, &r->scan_stats);
 413                 break;
 414         }
 415         prt_newline(out);
 416         printbuf_indent_sub(out, 2);
 417 }
 418
 419 void bch2_rebalance_stop(struct bch_fs *c)
 420 {
 421         struct task_struct *p;
 422
 423         c->rebalance.pd.rate.rate = UINT_MAX;
 424         bch2_ratelimit_reset(&c->rebalance.pd.rate);
 425
 426         p = rcu_dereference_protected(c->rebalance.thread, 1);
 427         c->rebalance.thread = NULL;
 428
 429         if (p) {
 430                 /* for sychronizing with rebalance_wakeup() */
 431                 synchronize_rcu();
 432
 433                 kthread_stop(p);
 434                 put_task_struct(p);
 435         }
 436 }
 437
 438 int bch2_rebalance_start(struct bch_fs *c)
 439 {
 440         struct task_struct *p;
 441         int ret;
 442
 443         if (c->rebalance.thread)
 444                 return 0;
 445
 446         if (c->opts.nochanges)
 447                 return 0;
 448
 449         p = kthread_create(bch2_rebalance_thread, c, "bch-rebalance/%s", c->name);
 450         ret = PTR_ERR_OR_ZERO(p);
 451         if (ret) {
 452                 bch_err_msg(c, ret, "creating rebalance thread");
 453                 return ret;
 454         }
 455
 456         get_task_struct(p);
 457         rcu_assign_pointer(c->rebalance.thread, p);
 458         wake_up_process(p);
 459         return 0;
 460 }
 461
 462 void bch2_fs_rebalance_init(struct bch_fs *c)
 463 {
 464         bch2_pd_controller_init(&c->rebalance.pd);
 465 }