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_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         return k;
 175 }
 176
 177 noinline_for_stack
 178 static int do_rebalance_extent(struct moving_context *ctxt,
 179                                struct bpos work_pos,
 180                                struct btree_iter *extent_iter)
 181 {
 182         struct btree_trans *trans = ctxt->trans;
 183         struct bch_fs *c = trans->c;
 184         struct bch_fs_rebalance *r = &trans->c->rebalance;
 185         struct data_update_opts data_opts;
 186         struct bch_io_opts io_opts;
 187         struct bkey_s_c k;
 188         struct bkey_buf sk;
 189         int ret;
 190
 191         ctxt->stats = &r->work_stats;
 192         r->state = BCH_REBALANCE_working;
 193
 194         bch2_bkey_buf_init(&sk);
 195
 196         ret = bkey_err(k = next_rebalance_extent(trans, work_pos,
 197                                                  extent_iter, &data_opts));
 198         if (ret || !k.k)
 199                 goto out;
 200
 201         ret = bch2_move_get_io_opts_one(trans, &io_opts, k);
 202         if (ret)
 203                 goto out;
 204
 205         atomic64_add(k.k->size, &ctxt->stats->sectors_seen);
 206
 207         /*
 208          * The iterator gets unlocked by __bch2_read_extent - need to
 209          * save a copy of @k elsewhere:
 210          */
 211         bch2_bkey_buf_reassemble(&sk, c, k);
 212         k = bkey_i_to_s_c(sk.k);
 213
 214         ret = bch2_move_extent(ctxt, NULL, extent_iter, k, io_opts, data_opts);
 215         if (ret) {
 216                 if (bch2_err_matches(ret, ENOMEM)) {
 217                         /* memory allocation failure, wait for some IO to finish */
 218                         bch2_move_ctxt_wait_for_io(ctxt);
 219                         ret = -BCH_ERR_transaction_restart_nested;
 220                 }
 221
 222                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 223                         goto out;
 224
 225                 /* skip it and continue, XXX signal failure */
 226                 ret = 0;
 227         }
 228 out:
 229         bch2_bkey_buf_exit(&sk, c);
 230         return ret;
 231 }
 232
 233 static bool rebalance_pred(struct bch_fs *c, void *arg,
 234                            struct bkey_s_c k,
 235                            struct bch_io_opts *io_opts,
 236                            struct data_update_opts *data_opts)
 237 {
 238         unsigned target, compression;
 239
 240         if (k.k->p.inode) {
 241                 target          = io_opts->background_target;
 242                 compression     = io_opts->background_compression ?: io_opts->compression;
 243         } else {
 244                 const struct bch_extent_rebalance *r = bch2_bkey_rebalance_opts(k);
 245
 246                 target          = r ? r->target : io_opts->background_target;
 247                 compression     = r ? r->compression :
 248                         (io_opts->background_compression ?: io_opts->compression);
 249         }
 250
 251         data_opts->rewrite_ptrs         = bch2_bkey_ptrs_need_rebalance(c, k, target, compression);
 252         data_opts->target               = target;
 253         return data_opts->rewrite_ptrs != 0;
 254 }
 255
 256 static int do_rebalance_scan(struct moving_context *ctxt, u64 inum, u64 cookie)
 257 {
 258         struct btree_trans *trans = ctxt->trans;
 259         struct bch_fs_rebalance *r = &trans->c->rebalance;
 260         int ret;
 261
 262         bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
 263         ctxt->stats = &r->scan_stats;
 264
 265         if (!inum) {
 266                 r->scan_start   = BBPOS_MIN;
 267                 r->scan_end     = BBPOS_MAX;
 268         } else {
 269                 r->scan_start   = BBPOS(BTREE_ID_extents, POS(inum, 0));
 270                 r->scan_end     = BBPOS(BTREE_ID_extents, POS(inum, U64_MAX));
 271         }
 272
 273         r->state = BCH_REBALANCE_scanning;
 274
 275         ret = __bch2_move_data(ctxt, r->scan_start, r->scan_end, rebalance_pred, NULL) ?:
 276                 commit_do(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
 277                           bch2_clear_rebalance_needs_scan(trans, inum, cookie));
 278
 279         bch2_move_stats_exit(&r->scan_stats, trans->c);
 280         return ret;
 281 }
 282
 283 static void rebalance_wait(struct bch_fs *c)
 284 {
 285         struct bch_fs_rebalance *r = &c->rebalance;
 286         struct io_clock *clock = &c->io_clock[WRITE];
 287         u64 now = atomic64_read(&clock->now);
 288         u64 min_member_capacity = bch2_min_rw_member_capacity(c);
 289
 290         if (min_member_capacity == U64_MAX)
 291                 min_member_capacity = 128 * 2048;
 292
 293         r->wait_iotime_end              = now + (min_member_capacity >> 6);
 294
 295         if (r->state != BCH_REBALANCE_waiting) {
 296                 r->wait_iotime_start    = now;
 297                 r->wait_wallclock_start = ktime_get_real_ns();
 298                 r->state                = BCH_REBALANCE_waiting;
 299         }
 300
 301         bch2_kthread_io_clock_wait(clock, r->wait_iotime_end, MAX_SCHEDULE_TIMEOUT);
 302 }
 303
 304 static int do_rebalance(struct moving_context *ctxt)
 305 {
 306         struct btree_trans *trans = ctxt->trans;
 307         struct bch_fs *c = trans->c;
 308         struct bch_fs_rebalance *r = &c->rebalance;
 309         struct btree_iter rebalance_work_iter, extent_iter = { NULL };
 310         struct bkey_s_c k;
 311         int ret = 0;
 312
 313         bch2_move_stats_init(&r->work_stats, "rebalance_work");
 314         bch2_move_stats_init(&r->scan_stats, "rebalance_scan");
 315
 316         bch2_trans_iter_init(trans, &rebalance_work_iter,
 317                              BTREE_ID_rebalance_work, POS_MIN,
 318                              BTREE_ITER_ALL_SNAPSHOTS);
 319
 320         while (!bch2_move_ratelimit(ctxt) &&
 321                !kthread_wait_freezable(r->enabled)) {
 322                 bch2_trans_begin(trans);
 323
 324                 ret = bkey_err(k = next_rebalance_entry(trans, &rebalance_work_iter));
 325                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 326                         continue;
 327                 if (ret || !k.k)
 328                         break;
 329
 330                 ret = k.k->type == KEY_TYPE_cookie
 331                         ? do_rebalance_scan(ctxt, k.k->p.inode,
 332                                             le64_to_cpu(bkey_s_c_to_cookie(k).v->cookie))
 333                         : do_rebalance_extent(ctxt, k.k->p, &extent_iter);
 334
 335                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 336                         continue;
 337                 if (ret)
 338                         break;
 339
 340                 bch2_btree_iter_advance(&rebalance_work_iter);
 341         }
 342
 343         bch2_trans_iter_exit(trans, &extent_iter);
 344         bch2_trans_iter_exit(trans, &rebalance_work_iter);
 345         bch2_move_stats_exit(&r->scan_stats, c);
 346
 347         if (!ret &&
 348             !kthread_should_stop() &&
 349             !atomic64_read(&r->work_stats.sectors_seen) &&
 350             !atomic64_read(&r->scan_stats.sectors_seen)) {
 351                 bch2_trans_unlock_long(trans);
 352                 rebalance_wait(c);
 353         }
 354
 355         if (!bch2_err_matches(ret, EROFS))
 356                 bch_err_fn(c, ret);
 357         return ret;
 358 }
 359
 360 static int bch2_rebalance_thread(void *arg)
 361 {
 362         struct bch_fs *c = arg;
 363         struct bch_fs_rebalance *r = &c->rebalance;
 364         struct moving_context ctxt;
 365         int ret;
 366
 367         set_freezable();
 368
 369         bch2_moving_ctxt_init(&ctxt, c, NULL, &r->work_stats,
 370                               writepoint_ptr(&c->rebalance_write_point),
 371                               true);
 372
 373         while (!kthread_should_stop() &&
 374                !(ret = do_rebalance(&ctxt)))
 375                 ;
 376
 377         bch2_moving_ctxt_exit(&ctxt);
 378
 379         return 0;
 380 }
 381
 382 void bch2_rebalance_status_to_text(struct printbuf *out, struct bch_fs *c)
 383 {
 384         struct bch_fs_rebalance *r = &c->rebalance;
 385
 386         prt_str(out, bch2_rebalance_state_strs[r->state]);
 387         prt_newline(out);
 388         printbuf_indent_add(out, 2);
 389
 390         switch (r->state) {
 391         case BCH_REBALANCE_waiting: {
 392                 u64 now = atomic64_read(&c->io_clock[WRITE].now);
 393
 394                 prt_str(out, "io wait duration:  ");
 395                 bch2_prt_human_readable_s64(out, r->wait_iotime_end - r->wait_iotime_start);
 396                 prt_newline(out);
 397
 398                 prt_str(out, "io wait remaining: ");
 399                 bch2_prt_human_readable_s64(out, r->wait_iotime_end - now);
 400                 prt_newline(out);
 401
 402                 prt_str(out, "duration waited:   ");
 403                 bch2_pr_time_units(out, ktime_get_real_ns() - r->wait_wallclock_start);
 404                 prt_newline(out);
 405                 break;
 406         }
 407         case BCH_REBALANCE_working:
 408                 bch2_move_stats_to_text(out, &r->work_stats);
 409                 break;
 410         case BCH_REBALANCE_scanning:
 411                 bch2_move_stats_to_text(out, &r->scan_stats);
 412                 break;
 413         }
 414         prt_newline(out);
 415         printbuf_indent_sub(out, 2);
 416 }
 417
 418 void bch2_rebalance_stop(struct bch_fs *c)
 419 {
 420         struct task_struct *p;
 421
 422         c->rebalance.pd.rate.rate = UINT_MAX;
 423         bch2_ratelimit_reset(&c->rebalance.pd.rate);
 424
 425         p = rcu_dereference_protected(c->rebalance.thread, 1);
 426         c->rebalance.thread = NULL;
 427
 428         if (p) {
 429                 /* for sychronizing with rebalance_wakeup() */
 430                 synchronize_rcu();
 431
 432                 kthread_stop(p);
 433                 put_task_struct(p);
 434         }
 435 }
 436
 437 int bch2_rebalance_start(struct bch_fs *c)
 438 {
 439         struct task_struct *p;
 440         int ret;
 441
 442         if (c->rebalance.thread)
 443                 return 0;
 444
 445         if (c->opts.nochanges)
 446                 return 0;
 447
 448         p = kthread_create(bch2_rebalance_thread, c, "bch-rebalance/%s", c->name);
 449         ret = PTR_ERR_OR_ZERO(p);
 450         if (ret) {
 451                 bch_err_msg(c, ret, "creating rebalance thread");
 452                 return ret;
 453         }
 454
 455         get_task_struct(p);
 456         rcu_assign_pointer(c->rebalance.thread, p);
 457         wake_up_process(p);
 458         return 0;
 459 }
 460
 461 void bch2_fs_rebalance_init(struct bch_fs *c)
 462 {
 463         bch2_pd_controller_init(&c->rebalance.pd);
 464 }