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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   4  * Copyright 2012 Google, Inc.
   5  */
   6
   7 #include "bcachefs.h"
   8 #include "alloc_foreground.h"
   9 #include "bkey_buf.h"
  10 #include "bset.h"
  11 #include "btree_update.h"
  12 #include "buckets.h"
  13 #include "checksum.h"
  14 #include "clock.h"
  15 #include "compress.h"
  16 #include "debug.h"
  17 #include "ec.h"
  18 #include "error.h"
  19 #include "extent_update.h"
  20 #include "inode.h"
  21 #include "io_write.h"
  22 #include "journal.h"
  23 #include "keylist.h"
  24 #include "move.h"
  25 #include "nocow_locking.h"
  26 #include "rebalance.h"
  27 #include "subvolume.h"
  28 #include "super.h"
  29 #include "super-io.h"
  30 #include "trace.h"
  31
  32 #include <linux/blkdev.h>
  33 #include <linux/prefetch.h>
  34 #include <linux/random.h>
  35 #include <linux/sched/mm.h>
  36
  37 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
  38
  39 static inline void bch2_congested_acct(struct bch_dev *ca, u64 io_latency,
  40                                        u64 now, int rw)
  41 {
  42         u64 latency_capable =
  43                 ca->io_latency[rw].quantiles.entries[QUANTILE_IDX(1)].m;
  44         /* ideally we'd be taking into account the device's variance here: */
  45         u64 latency_threshold = latency_capable << (rw == READ ? 2 : 3);
  46         s64 latency_over = io_latency - latency_threshold;
  47
  48         if (latency_threshold && latency_over > 0) {
  49                 /*
  50                  * bump up congested by approximately latency_over * 4 /
  51                  * latency_threshold - we don't need much accuracy here so don't
  52                  * bother with the divide:
  53                  */
  54                 if (atomic_read(&ca->congested) < CONGESTED_MAX)
  55                         atomic_add(latency_over >>
  56                                    max_t(int, ilog2(latency_threshold) - 2, 0),
  57                                    &ca->congested);
  58
  59                 ca->congested_last = now;
  60         } else if (atomic_read(&ca->congested) > 0) {
  61                 atomic_dec(&ca->congested);
  62         }
  63 }
  64
  65 void bch2_latency_acct(struct bch_dev *ca, u64 submit_time, int rw)
  66 {
  67         atomic64_t *latency = &ca->cur_latency[rw];
  68         u64 now = local_clock();
  69         u64 io_latency = time_after64(now, submit_time)
  70                 ? now - submit_time
  71                 : 0;
  72         u64 old, new, v = atomic64_read(latency);
  73
  74         do {
  75                 old = v;
  76
  77                 /*
  78                  * If the io latency was reasonably close to the current
  79                  * latency, skip doing the update and atomic operation - most of
  80                  * the time:
  81                  */
  82                 if (abs((int) (old - io_latency)) < (old >> 1) &&
  83                     now & ~(~0U << 5))
  84                         break;
  85
  86                 new = ewma_add(old, io_latency, 5);
  87         } while ((v = atomic64_cmpxchg(latency, old, new)) != old);
  88
  89         bch2_congested_acct(ca, io_latency, now, rw);
  90
  91         __time_stats_update(&ca->io_latency[rw].stats, submit_time, now);
  92 }
  93
  94 #endif
  95
  96 /* Allocate, free from mempool: */
  97
  98 void bch2_bio_free_pages_pool(struct bch_fs *c, struct bio *bio)
  99 {
 100         struct bvec_iter_all iter;
 101         struct bio_vec *bv;
 102
 103         bio_for_each_segment_all(bv, bio, iter)
 104                 if (bv->bv_page != ZERO_PAGE(0))
 105                         mempool_free(bv->bv_page, &c->bio_bounce_pages);
 106         bio->bi_vcnt = 0;
 107 }
 108
 109 static struct page *__bio_alloc_page_pool(struct bch_fs *c, bool *using_mempool)
 110 {
 111         struct page *page;
 112
 113         if (likely(!*using_mempool)) {
 114                 page = alloc_page(GFP_NOFS);
 115                 if (unlikely(!page)) {
 116                         mutex_lock(&c->bio_bounce_pages_lock);
 117                         *using_mempool = true;
 118                         goto pool_alloc;
 119
 120                 }
 121         } else {
 122 pool_alloc:
 123                 page = mempool_alloc(&c->bio_bounce_pages, GFP_NOFS);
 124         }
 125
 126         return page;
 127 }
 128
 129 void bch2_bio_alloc_pages_pool(struct bch_fs *c, struct bio *bio,
 130                                size_t size)
 131 {
 132         bool using_mempool = false;
 133
 134         while (size) {
 135                 struct page *page = __bio_alloc_page_pool(c, &using_mempool);
 136                 unsigned len = min_t(size_t, PAGE_SIZE, size);
 137
 138                 BUG_ON(!bio_add_page(bio, page, len, 0));
 139                 size -= len;
 140         }
 141
 142         if (using_mempool)
 143                 mutex_unlock(&c->bio_bounce_pages_lock);
 144 }
 145
 146 /* Extent update path: */
 147
 148 int bch2_sum_sector_overwrites(struct btree_trans *trans,
 149                                struct btree_iter *extent_iter,
 150                                struct bkey_i *new,
 151                                bool *usage_increasing,
 152                                s64 *i_sectors_delta,
 153                                s64 *disk_sectors_delta)
 154 {
 155         struct bch_fs *c = trans->c;
 156         struct btree_iter iter;
 157         struct bkey_s_c old;
 158         unsigned new_replicas = bch2_bkey_replicas(c, bkey_i_to_s_c(new));
 159         bool new_compressed = bch2_bkey_sectors_compressed(bkey_i_to_s_c(new));
 160         int ret = 0;
 161
 162         *usage_increasing       = false;
 163         *i_sectors_delta        = 0;
 164         *disk_sectors_delta     = 0;
 165
 166         bch2_trans_copy_iter(&iter, extent_iter);
 167
 168         for_each_btree_key_upto_continue_norestart(iter,
 169                                 new->k.p, BTREE_ITER_SLOTS, old, ret) {
 170                 s64 sectors = min(new->k.p.offset, old.k->p.offset) -
 171                         max(bkey_start_offset(&new->k),
 172                             bkey_start_offset(old.k));
 173
 174                 *i_sectors_delta += sectors *
 175                         (bkey_extent_is_allocation(&new->k) -
 176                          bkey_extent_is_allocation(old.k));
 177
 178                 *disk_sectors_delta += sectors * bch2_bkey_nr_ptrs_allocated(bkey_i_to_s_c(new));
 179                 *disk_sectors_delta -= new->k.p.snapshot == old.k->p.snapshot
 180                         ? sectors * bch2_bkey_nr_ptrs_fully_allocated(old)
 181                         : 0;
 182
 183                 if (!*usage_increasing &&
 184                     (new->k.p.snapshot != old.k->p.snapshot ||
 185                      new_replicas > bch2_bkey_replicas(c, old) ||
 186                      (!new_compressed && bch2_bkey_sectors_compressed(old))))
 187                         *usage_increasing = true;
 188
 189                 if (bkey_ge(old.k->p, new->k.p))
 190                         break;
 191         }
 192
 193         bch2_trans_iter_exit(trans, &iter);
 194         return ret;
 195 }
 196
 197 static inline int bch2_extent_update_i_size_sectors(struct btree_trans *trans,
 198                                                     struct btree_iter *extent_iter,
 199                                                     u64 new_i_size,
 200                                                     s64 i_sectors_delta)
 201 {
 202         struct btree_iter iter;
 203         struct bkey_i *k;
 204         struct bkey_i_inode_v3 *inode;
 205         /*
 206          * Crazy performance optimization:
 207          * Every extent update needs to also update the inode: the inode trigger
 208          * will set bi->journal_seq to the journal sequence number of this
 209          * transaction - for fsync.
 210          *
 211          * But if that's the only reason we're updating the inode (we're not
 212          * updating bi_size or bi_sectors), then we don't need the inode update
 213          * to be journalled - if we crash, the bi_journal_seq update will be
 214          * lost, but that's fine.
 215          */
 216         unsigned inode_update_flags = BTREE_UPDATE_NOJOURNAL;
 217         int ret;
 218
 219         k = bch2_bkey_get_mut_noupdate(trans, &iter, BTREE_ID_inodes,
 220                               SPOS(0,
 221                                    extent_iter->pos.inode,
 222                                    extent_iter->snapshot),
 223                               BTREE_ITER_CACHED);
 224         ret = PTR_ERR_OR_ZERO(k);
 225         if (unlikely(ret))
 226                 return ret;
 227
 228         if (unlikely(k->k.type != KEY_TYPE_inode_v3)) {
 229                 k = bch2_inode_to_v3(trans, k);
 230                 ret = PTR_ERR_OR_ZERO(k);
 231                 if (unlikely(ret))
 232                         goto err;
 233         }
 234
 235         inode = bkey_i_to_inode_v3(k);
 236
 237         if (!(le64_to_cpu(inode->v.bi_flags) & BCH_INODE_i_size_dirty) &&
 238             new_i_size > le64_to_cpu(inode->v.bi_size)) {
 239                 inode->v.bi_size = cpu_to_le64(new_i_size);
 240                 inode_update_flags = 0;
 241         }
 242
 243         if (i_sectors_delta) {
 244                 le64_add_cpu(&inode->v.bi_sectors, i_sectors_delta);
 245                 inode_update_flags = 0;
 246         }
 247
 248         if (inode->k.p.snapshot != iter.snapshot) {
 249                 inode->k.p.snapshot = iter.snapshot;
 250                 inode_update_flags = 0;
 251         }
 252
 253         ret = bch2_trans_update(trans, &iter, &inode->k_i,
 254                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
 255                                 inode_update_flags);
 256 err:
 257         bch2_trans_iter_exit(trans, &iter);
 258         return ret;
 259 }
 260
 261 int bch2_extent_update(struct btree_trans *trans,
 262                        subvol_inum inum,
 263                        struct btree_iter *iter,
 264                        struct bkey_i *k,
 265                        struct disk_reservation *disk_res,
 266                        u64 new_i_size,
 267                        s64 *i_sectors_delta_total,
 268                        bool check_enospc)
 269 {
 270         struct bpos next_pos;
 271         bool usage_increasing;
 272         s64 i_sectors_delta = 0, disk_sectors_delta = 0;
 273         int ret;
 274
 275         /*
 276          * This traverses us the iterator without changing iter->path->pos to
 277          * search_key() (which is pos + 1 for extents): we want there to be a
 278          * path already traversed at iter->pos because
 279          * bch2_trans_extent_update() will use it to attempt extent merging
 280          */
 281         ret = __bch2_btree_iter_traverse(iter);
 282         if (ret)
 283                 return ret;
 284
 285         ret = bch2_extent_trim_atomic(trans, iter, k);
 286         if (ret)
 287                 return ret;
 288
 289         next_pos = k->k.p;
 290
 291         ret = bch2_sum_sector_overwrites(trans, iter, k,
 292                         &usage_increasing,
 293                         &i_sectors_delta,
 294                         &disk_sectors_delta);
 295         if (ret)
 296                 return ret;
 297
 298         if (disk_res &&
 299             disk_sectors_delta > (s64) disk_res->sectors) {
 300                 ret = bch2_disk_reservation_add(trans->c, disk_res,
 301                                         disk_sectors_delta - disk_res->sectors,
 302                                         !check_enospc || !usage_increasing
 303                                         ? BCH_DISK_RESERVATION_NOFAIL : 0);
 304                 if (ret)
 305                         return ret;
 306         }
 307
 308         /*
 309          * Note:
 310          * We always have to do an inode update - even when i_size/i_sectors
 311          * aren't changing - for fsync to work properly; fsync relies on
 312          * inode->bi_journal_seq which is updated by the trigger code:
 313          */
 314         ret =   bch2_extent_update_i_size_sectors(trans, iter,
 315                                                   min(k->k.p.offset << 9, new_i_size),
 316                                                   i_sectors_delta) ?:
 317                 bch2_trans_update(trans, iter, k, 0) ?:
 318                 bch2_trans_commit(trans, disk_res, NULL,
 319                                 BCH_TRANS_COMMIT_no_check_rw|
 320                                 BCH_TRANS_COMMIT_no_enospc);
 321         if (unlikely(ret))
 322                 return ret;
 323
 324         if (i_sectors_delta_total)
 325                 *i_sectors_delta_total += i_sectors_delta;
 326         bch2_btree_iter_set_pos(iter, next_pos);
 327         return 0;
 328 }
 329
 330 static int bch2_write_index_default(struct bch_write_op *op)
 331 {
 332         struct bch_fs *c = op->c;
 333         struct bkey_buf sk;
 334         struct keylist *keys = &op->insert_keys;
 335         struct bkey_i *k = bch2_keylist_front(keys);
 336         struct btree_trans *trans = bch2_trans_get(c);
 337         struct btree_iter iter;
 338         subvol_inum inum = {
 339                 .subvol = op->subvol,
 340                 .inum   = k->k.p.inode,
 341         };
 342         int ret;
 343
 344         BUG_ON(!inum.subvol);
 345
 346         bch2_bkey_buf_init(&sk);
 347
 348         do {
 349                 bch2_trans_begin(trans);
 350
 351                 k = bch2_keylist_front(keys);
 352                 bch2_bkey_buf_copy(&sk, c, k);
 353
 354                 ret = bch2_subvolume_get_snapshot(trans, inum.subvol,
 355                                                   &sk.k->k.p.snapshot);
 356                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 357                         continue;
 358                 if (ret)
 359                         break;
 360
 361                 bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
 362                                      bkey_start_pos(&sk.k->k),
 363                                      BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 364
 365                 ret =   bch2_bkey_set_needs_rebalance(c, sk.k, &op->opts) ?:
 366                         bch2_extent_update(trans, inum, &iter, sk.k,
 367                                         &op->res,
 368                                         op->new_i_size, &op->i_sectors_delta,
 369                                         op->flags & BCH_WRITE_CHECK_ENOSPC);
 370                 bch2_trans_iter_exit(trans, &iter);
 371
 372                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 373                         continue;
 374                 if (ret)
 375                         break;
 376
 377                 if (bkey_ge(iter.pos, k->k.p))
 378                         bch2_keylist_pop_front(&op->insert_keys);
 379                 else
 380                         bch2_cut_front(iter.pos, k);
 381         } while (!bch2_keylist_empty(keys));
 382
 383         bch2_trans_put(trans);
 384         bch2_bkey_buf_exit(&sk, c);
 385
 386         return ret;
 387 }
 388
 389 /* Writes */
 390
 391 void bch2_submit_wbio_replicas(struct bch_write_bio *wbio, struct bch_fs *c,
 392                                enum bch_data_type type,
 393                                const struct bkey_i *k,
 394                                bool nocow)
 395 {
 396         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(bkey_i_to_s_c(k));
 397         struct bch_write_bio *n;
 398
 399         BUG_ON(c->opts.nochanges);
 400
 401         bkey_for_each_ptr(ptrs, ptr) {
 402                 BUG_ON(!bch2_dev_exists2(c, ptr->dev));
 403
 404                 struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
 405
 406                 if (to_entry(ptr + 1) < ptrs.end) {
 407                         n = to_wbio(bio_alloc_clone(NULL, &wbio->bio,
 408                                                 GFP_NOFS, &ca->replica_set));
 409
 410                         n->bio.bi_end_io        = wbio->bio.bi_end_io;
 411                         n->bio.bi_private       = wbio->bio.bi_private;
 412                         n->parent               = wbio;
 413                         n->split                = true;
 414                         n->bounce               = false;
 415                         n->put_bio              = true;
 416                         n->bio.bi_opf           = wbio->bio.bi_opf;
 417                         bio_inc_remaining(&wbio->bio);
 418                 } else {
 419                         n = wbio;
 420                         n->split                = false;
 421                 }
 422
 423                 n->c                    = c;
 424                 n->dev                  = ptr->dev;
 425                 n->have_ioref           = nocow || bch2_dev_get_ioref(ca,
 426                                         type == BCH_DATA_btree ? READ : WRITE);
 427                 n->nocow                = nocow;
 428                 n->submit_time          = local_clock();
 429                 n->inode_offset         = bkey_start_offset(&k->k);
 430                 n->bio.bi_iter.bi_sector = ptr->offset;
 431
 432                 if (likely(n->have_ioref)) {
 433                         this_cpu_add(ca->io_done->sectors[WRITE][type],
 434                                      bio_sectors(&n->bio));
 435
 436                         bio_set_dev(&n->bio, ca->disk_sb.bdev);
 437
 438                         if (type != BCH_DATA_btree && unlikely(c->opts.no_data_io)) {
 439                                 bio_endio(&n->bio);
 440                                 continue;
 441                         }
 442
 443                         submit_bio(&n->bio);
 444                 } else {
 445                         n->bio.bi_status        = BLK_STS_REMOVED;
 446                         bio_endio(&n->bio);
 447                 }
 448         }
 449 }
 450
 451 static void __bch2_write(struct bch_write_op *);
 452
 453 static void bch2_write_done(struct closure *cl)
 454 {
 455         struct bch_write_op *op = container_of(cl, struct bch_write_op, cl);
 456         struct bch_fs *c = op->c;
 457
 458         EBUG_ON(op->open_buckets.nr);
 459
 460         time_stats_update(&c->times[BCH_TIME_data_write], op->start_time);
 461         bch2_disk_reservation_put(c, &op->res);
 462
 463         if (!(op->flags & BCH_WRITE_MOVE))
 464                 bch2_write_ref_put(c, BCH_WRITE_REF_write);
 465         bch2_keylist_free(&op->insert_keys, op->inline_keys);
 466
 467         EBUG_ON(cl->parent);
 468         closure_debug_destroy(cl);
 469         if (op->end_io)
 470                 op->end_io(op);
 471 }
 472
 473 static noinline int bch2_write_drop_io_error_ptrs(struct bch_write_op *op)
 474 {
 475         struct keylist *keys = &op->insert_keys;
 476         struct bch_extent_ptr *ptr;
 477         struct bkey_i *src, *dst = keys->keys, *n;
 478
 479         for (src = keys->keys; src != keys->top; src = n) {
 480                 n = bkey_next(src);
 481
 482                 if (bkey_extent_is_direct_data(&src->k)) {
 483                         bch2_bkey_drop_ptrs(bkey_i_to_s(src), ptr,
 484                                             test_bit(ptr->dev, op->failed.d));
 485
 486                         if (!bch2_bkey_nr_ptrs(bkey_i_to_s_c(src)))
 487                                 return -EIO;
 488                 }
 489
 490                 if (dst != src)
 491                         memmove_u64s_down(dst, src, src->k.u64s);
 492                 dst = bkey_next(dst);
 493         }
 494
 495         keys->top = dst;
 496         return 0;
 497 }
 498
 499 /**
 500  * __bch2_write_index - after a write, update index to point to new data
 501  * @op:         bch_write_op to process
 502  */
 503 static void __bch2_write_index(struct bch_write_op *op)
 504 {
 505         struct bch_fs *c = op->c;
 506         struct keylist *keys = &op->insert_keys;
 507         unsigned dev;
 508         int ret = 0;
 509
 510         if (unlikely(op->flags & BCH_WRITE_IO_ERROR)) {
 511                 ret = bch2_write_drop_io_error_ptrs(op);
 512                 if (ret)
 513                         goto err;
 514         }
 515
 516         if (!bch2_keylist_empty(keys)) {
 517                 u64 sectors_start = keylist_sectors(keys);
 518
 519                 ret = !(op->flags & BCH_WRITE_MOVE)
 520                         ? bch2_write_index_default(op)
 521                         : bch2_data_update_index_update(op);
 522
 523                 BUG_ON(bch2_err_matches(ret, BCH_ERR_transaction_restart));
 524                 BUG_ON(keylist_sectors(keys) && !ret);
 525
 526                 op->written += sectors_start - keylist_sectors(keys);
 527
 528                 if (ret && !bch2_err_matches(ret, EROFS)) {
 529                         struct bkey_i *insert = bch2_keylist_front(&op->insert_keys);
 530
 531                         bch_err_inum_offset_ratelimited(c,
 532                                 insert->k.p.inode, insert->k.p.offset << 9,
 533                                 "write error while doing btree update: %s",
 534                                 bch2_err_str(ret));
 535                 }
 536
 537                 if (ret)
 538                         goto err;
 539         }
 540 out:
 541         /* If some a bucket wasn't written, we can't erasure code it: */
 542         for_each_set_bit(dev, op->failed.d, BCH_SB_MEMBERS_MAX)
 543                 bch2_open_bucket_write_error(c, &op->open_buckets, dev);
 544
 545         bch2_open_buckets_put(c, &op->open_buckets);
 546         return;
 547 err:
 548         keys->top = keys->keys;
 549         op->error = ret;
 550         op->flags |= BCH_WRITE_DONE;
 551         goto out;
 552 }
 553
 554 static inline void __wp_update_state(struct write_point *wp, enum write_point_state state)
 555 {
 556         if (state != wp->state) {
 557                 u64 now = ktime_get_ns();
 558
 559                 if (wp->last_state_change &&
 560                     time_after64(now, wp->last_state_change))
 561                         wp->time[wp->state] += now - wp->last_state_change;
 562                 wp->state = state;
 563                 wp->last_state_change = now;
 564         }
 565 }
 566
 567 static inline void wp_update_state(struct write_point *wp, bool running)
 568 {
 569         enum write_point_state state;
 570
 571         state = running                  ? WRITE_POINT_running :
 572                 !list_empty(&wp->writes) ? WRITE_POINT_waiting_io
 573                                          : WRITE_POINT_stopped;
 574
 575         __wp_update_state(wp, state);
 576 }
 577
 578 static CLOSURE_CALLBACK(bch2_write_index)
 579 {
 580         closure_type(op, struct bch_write_op, cl);
 581         struct write_point *wp = op->wp;
 582         struct workqueue_struct *wq = index_update_wq(op);
 583         unsigned long flags;
 584
 585         if ((op->flags & BCH_WRITE_DONE) &&
 586             (op->flags & BCH_WRITE_MOVE))
 587                 bch2_bio_free_pages_pool(op->c, &op->wbio.bio);
 588
 589         spin_lock_irqsave(&wp->writes_lock, flags);
 590         if (wp->state == WRITE_POINT_waiting_io)
 591                 __wp_update_state(wp, WRITE_POINT_waiting_work);
 592         list_add_tail(&op->wp_list, &wp->writes);
 593         spin_unlock_irqrestore (&wp->writes_lock, flags);
 594
 595         queue_work(wq, &wp->index_update_work);
 596 }
 597
 598 static inline void bch2_write_queue(struct bch_write_op *op, struct write_point *wp)
 599 {
 600         op->wp = wp;
 601
 602         if (wp->state == WRITE_POINT_stopped) {
 603                 spin_lock_irq(&wp->writes_lock);
 604                 __wp_update_state(wp, WRITE_POINT_waiting_io);
 605                 spin_unlock_irq(&wp->writes_lock);
 606         }
 607 }
 608
 609 void bch2_write_point_do_index_updates(struct work_struct *work)
 610 {
 611         struct write_point *wp =
 612                 container_of(work, struct write_point, index_update_work);
 613         struct bch_write_op *op;
 614
 615         while (1) {
 616                 spin_lock_irq(&wp->writes_lock);
 617                 op = list_first_entry_or_null(&wp->writes, struct bch_write_op, wp_list);
 618                 if (op)
 619                         list_del(&op->wp_list);
 620                 wp_update_state(wp, op != NULL);
 621                 spin_unlock_irq(&wp->writes_lock);
 622
 623                 if (!op)
 624                         break;
 625
 626                 op->flags |= BCH_WRITE_IN_WORKER;
 627
 628                 __bch2_write_index(op);
 629
 630                 if (!(op->flags & BCH_WRITE_DONE))
 631                         __bch2_write(op);
 632                 else
 633                         bch2_write_done(&op->cl);
 634         }
 635 }
 636
 637 static void bch2_write_endio(struct bio *bio)
 638 {
 639         struct closure *cl              = bio->bi_private;
 640         struct bch_write_op *op         = container_of(cl, struct bch_write_op, cl);
 641         struct bch_write_bio *wbio      = to_wbio(bio);
 642         struct bch_write_bio *parent    = wbio->split ? wbio->parent : NULL;
 643         struct bch_fs *c                = wbio->c;
 644         struct bch_dev *ca              = bch_dev_bkey_exists(c, wbio->dev);
 645
 646         if (bch2_dev_inum_io_err_on(bio->bi_status, ca, BCH_MEMBER_ERROR_write,
 647                                     op->pos.inode,
 648                                     wbio->inode_offset << 9,
 649                                     "data write error: %s",
 650                                     bch2_blk_status_to_str(bio->bi_status))) {
 651                 set_bit(wbio->dev, op->failed.d);
 652                 op->flags |= BCH_WRITE_IO_ERROR;
 653         }
 654
 655         if (wbio->nocow)
 656                 set_bit(wbio->dev, op->devs_need_flush->d);
 657
 658         if (wbio->have_ioref) {
 659                 bch2_latency_acct(ca, wbio->submit_time, WRITE);
 660                 percpu_ref_put(&ca->io_ref);
 661         }
 662
 663         if (wbio->bounce)
 664                 bch2_bio_free_pages_pool(c, bio);
 665
 666         if (wbio->put_bio)
 667                 bio_put(bio);
 668
 669         if (parent)
 670                 bio_endio(&parent->bio);
 671         else
 672                 closure_put(cl);
 673 }
 674
 675 static void init_append_extent(struct bch_write_op *op,
 676                                struct write_point *wp,
 677                                struct bversion version,
 678                                struct bch_extent_crc_unpacked crc)
 679 {
 680         struct bkey_i_extent *e;
 681
 682         op->pos.offset += crc.uncompressed_size;
 683
 684         e = bkey_extent_init(op->insert_keys.top);
 685         e->k.p          = op->pos;
 686         e->k.size       = crc.uncompressed_size;
 687         e->k.version    = version;
 688
 689         if (crc.csum_type ||
 690             crc.compression_type ||
 691             crc.nonce)
 692                 bch2_extent_crc_append(&e->k_i, crc);
 693
 694         bch2_alloc_sectors_append_ptrs_inlined(op->c, wp, &e->k_i, crc.compressed_size,
 695                                        op->flags & BCH_WRITE_CACHED);
 696
 697         bch2_keylist_push(&op->insert_keys);
 698 }
 699
 700 static struct bio *bch2_write_bio_alloc(struct bch_fs *c,
 701                                         struct write_point *wp,
 702                                         struct bio *src,
 703                                         bool *page_alloc_failed,
 704                                         void *buf)
 705 {
 706         struct bch_write_bio *wbio;
 707         struct bio *bio;
 708         unsigned output_available =
 709                 min(wp->sectors_free << 9, src->bi_iter.bi_size);
 710         unsigned pages = DIV_ROUND_UP(output_available +
 711                                       (buf
 712                                        ? ((unsigned long) buf & (PAGE_SIZE - 1))
 713                                        : 0), PAGE_SIZE);
 714
 715         pages = min(pages, BIO_MAX_VECS);
 716
 717         bio = bio_alloc_bioset(NULL, pages, 0,
 718                                GFP_NOFS, &c->bio_write);
 719         wbio                    = wbio_init(bio);
 720         wbio->put_bio           = true;
 721         /* copy WRITE_SYNC flag */
 722         wbio->bio.bi_opf        = src->bi_opf;
 723
 724         if (buf) {
 725                 bch2_bio_map(bio, buf, output_available);
 726                 return bio;
 727         }
 728
 729         wbio->bounce            = true;
 730
 731         /*
 732          * We can't use mempool for more than c->sb.encoded_extent_max
 733          * worth of pages, but we'd like to allocate more if we can:
 734          */
 735         bch2_bio_alloc_pages_pool(c, bio,
 736                                   min_t(unsigned, output_available,
 737                                         c->opts.encoded_extent_max));
 738
 739         if (bio->bi_iter.bi_size < output_available)
 740                 *page_alloc_failed =
 741                         bch2_bio_alloc_pages(bio,
 742                                              output_available -
 743                                              bio->bi_iter.bi_size,
 744                                              GFP_NOFS) != 0;
 745
 746         return bio;
 747 }
 748
 749 static int bch2_write_rechecksum(struct bch_fs *c,
 750                                  struct bch_write_op *op,
 751                                  unsigned new_csum_type)
 752 {
 753         struct bio *bio = &op->wbio.bio;
 754         struct bch_extent_crc_unpacked new_crc;
 755         int ret;
 756
 757         /* bch2_rechecksum_bio() can't encrypt or decrypt data: */
 758
 759         if (bch2_csum_type_is_encryption(op->crc.csum_type) !=
 760             bch2_csum_type_is_encryption(new_csum_type))
 761                 new_csum_type = op->crc.csum_type;
 762
 763         ret = bch2_rechecksum_bio(c, bio, op->version, op->crc,
 764                                   NULL, &new_crc,
 765                                   op->crc.offset, op->crc.live_size,
 766                                   new_csum_type);
 767         if (ret)
 768                 return ret;
 769
 770         bio_advance(bio, op->crc.offset << 9);
 771         bio->bi_iter.bi_size = op->crc.live_size << 9;
 772         op->crc = new_crc;
 773         return 0;
 774 }
 775
 776 static int bch2_write_decrypt(struct bch_write_op *op)
 777 {
 778         struct bch_fs *c = op->c;
 779         struct nonce nonce = extent_nonce(op->version, op->crc);
 780         struct bch_csum csum;
 781         int ret;
 782
 783         if (!bch2_csum_type_is_encryption(op->crc.csum_type))
 784                 return 0;
 785
 786         /*
 787          * If we need to decrypt data in the write path, we'll no longer be able
 788          * to verify the existing checksum (poly1305 mac, in this case) after
 789          * it's decrypted - this is the last point we'll be able to reverify the
 790          * checksum:
 791          */
 792         csum = bch2_checksum_bio(c, op->crc.csum_type, nonce, &op->wbio.bio);
 793         if (bch2_crc_cmp(op->crc.csum, csum) && !c->opts.no_data_io)
 794                 return -EIO;
 795
 796         ret = bch2_encrypt_bio(c, op->crc.csum_type, nonce, &op->wbio.bio);
 797         op->crc.csum_type = 0;
 798         op->crc.csum = (struct bch_csum) { 0, 0 };
 799         return ret;
 800 }
 801
 802 static enum prep_encoded_ret {
 803         PREP_ENCODED_OK,
 804         PREP_ENCODED_ERR,
 805         PREP_ENCODED_CHECKSUM_ERR,
 806         PREP_ENCODED_DO_WRITE,
 807 } bch2_write_prep_encoded_data(struct bch_write_op *op, struct write_point *wp)
 808 {
 809         struct bch_fs *c = op->c;
 810         struct bio *bio = &op->wbio.bio;
 811
 812         if (!(op->flags & BCH_WRITE_DATA_ENCODED))
 813                 return PREP_ENCODED_OK;
 814
 815         BUG_ON(bio_sectors(bio) != op->crc.compressed_size);
 816
 817         /* Can we just write the entire extent as is? */
 818         if (op->crc.uncompressed_size == op->crc.live_size &&
 819             op->crc.uncompressed_size <= c->opts.encoded_extent_max >> 9 &&
 820             op->crc.compressed_size <= wp->sectors_free &&
 821             (op->crc.compression_type == bch2_compression_opt_to_type(op->compression_opt) ||
 822              op->incompressible)) {
 823                 if (!crc_is_compressed(op->crc) &&
 824                     op->csum_type != op->crc.csum_type &&
 825                     bch2_write_rechecksum(c, op, op->csum_type) &&
 826                     !c->opts.no_data_io)
 827                         return PREP_ENCODED_CHECKSUM_ERR;
 828
 829                 return PREP_ENCODED_DO_WRITE;
 830         }
 831
 832         /*
 833          * If the data is compressed and we couldn't write the entire extent as
 834          * is, we have to decompress it:
 835          */
 836         if (crc_is_compressed(op->crc)) {
 837                 struct bch_csum csum;
 838
 839                 if (bch2_write_decrypt(op))
 840                         return PREP_ENCODED_CHECKSUM_ERR;
 841
 842                 /* Last point we can still verify checksum: */
 843                 csum = bch2_checksum_bio(c, op->crc.csum_type,
 844                                          extent_nonce(op->version, op->crc),
 845                                          bio);
 846                 if (bch2_crc_cmp(op->crc.csum, csum) && !c->opts.no_data_io)
 847                         return PREP_ENCODED_CHECKSUM_ERR;
 848
 849                 if (bch2_bio_uncompress_inplace(c, bio, &op->crc))
 850                         return PREP_ENCODED_ERR;
 851         }
 852
 853         /*
 854          * No longer have compressed data after this point - data might be
 855          * encrypted:
 856          */
 857
 858         /*
 859          * If the data is checksummed and we're only writing a subset,
 860          * rechecksum and adjust bio to point to currently live data:
 861          */
 862         if ((op->crc.live_size != op->crc.uncompressed_size ||
 863              op->crc.csum_type != op->csum_type) &&
 864             bch2_write_rechecksum(c, op, op->csum_type) &&
 865             !c->opts.no_data_io)
 866                 return PREP_ENCODED_CHECKSUM_ERR;
 867
 868         /*
 869          * If we want to compress the data, it has to be decrypted:
 870          */
 871         if ((op->compression_opt ||
 872              bch2_csum_type_is_encryption(op->crc.csum_type) !=
 873              bch2_csum_type_is_encryption(op->csum_type)) &&
 874             bch2_write_decrypt(op))
 875                 return PREP_ENCODED_CHECKSUM_ERR;
 876
 877         return PREP_ENCODED_OK;
 878 }
 879
 880 static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
 881                              struct bio **_dst)
 882 {
 883         struct bch_fs *c = op->c;
 884         struct bio *src = &op->wbio.bio, *dst = src;
 885         struct bvec_iter saved_iter;
 886         void *ec_buf;
 887         unsigned total_output = 0, total_input = 0;
 888         bool bounce = false;
 889         bool page_alloc_failed = false;
 890         int ret, more = 0;
 891
 892         BUG_ON(!bio_sectors(src));
 893
 894         ec_buf = bch2_writepoint_ec_buf(c, wp);
 895
 896         switch (bch2_write_prep_encoded_data(op, wp)) {
 897         case PREP_ENCODED_OK:
 898                 break;
 899         case PREP_ENCODED_ERR:
 900                 ret = -EIO;
 901                 goto err;
 902         case PREP_ENCODED_CHECKSUM_ERR:
 903                 goto csum_err;
 904         case PREP_ENCODED_DO_WRITE:
 905                 /* XXX look for bug here */
 906                 if (ec_buf) {
 907                         dst = bch2_write_bio_alloc(c, wp, src,
 908                                                    &page_alloc_failed,
 909                                                    ec_buf);
 910                         bio_copy_data(dst, src);
 911                         bounce = true;
 912                 }
 913                 init_append_extent(op, wp, op->version, op->crc);
 914                 goto do_write;
 915         }
 916
 917         if (ec_buf ||
 918             op->compression_opt ||
 919             (op->csum_type &&
 920              !(op->flags & BCH_WRITE_PAGES_STABLE)) ||
 921             (bch2_csum_type_is_encryption(op->csum_type) &&
 922              !(op->flags & BCH_WRITE_PAGES_OWNED))) {
 923                 dst = bch2_write_bio_alloc(c, wp, src,
 924                                            &page_alloc_failed,
 925                                            ec_buf);
 926                 bounce = true;
 927         }
 928
 929         saved_iter = dst->bi_iter;
 930
 931         do {
 932                 struct bch_extent_crc_unpacked crc = { 0 };
 933                 struct bversion version = op->version;
 934                 size_t dst_len = 0, src_len = 0;
 935
 936                 if (page_alloc_failed &&
 937                     dst->bi_iter.bi_size  < (wp->sectors_free << 9) &&
 938                     dst->bi_iter.bi_size < c->opts.encoded_extent_max)
 939                         break;
 940
 941                 BUG_ON(op->compression_opt &&
 942                        (op->flags & BCH_WRITE_DATA_ENCODED) &&
 943                        bch2_csum_type_is_encryption(op->crc.csum_type));
 944                 BUG_ON(op->compression_opt && !bounce);
 945
 946                 crc.compression_type = op->incompressible
 947                         ? BCH_COMPRESSION_TYPE_incompressible
 948                         : op->compression_opt
 949                         ? bch2_bio_compress(c, dst, &dst_len, src, &src_len,
 950                                             op->compression_opt)
 951                         : 0;
 952                 if (!crc_is_compressed(crc)) {
 953                         dst_len = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
 954                         dst_len = min_t(unsigned, dst_len, wp->sectors_free << 9);
 955
 956                         if (op->csum_type)
 957                                 dst_len = min_t(unsigned, dst_len,
 958                                                 c->opts.encoded_extent_max);
 959
 960                         if (bounce) {
 961                                 swap(dst->bi_iter.bi_size, dst_len);
 962                                 bio_copy_data(dst, src);
 963                                 swap(dst->bi_iter.bi_size, dst_len);
 964                         }
 965
 966                         src_len = dst_len;
 967                 }
 968
 969                 BUG_ON(!src_len || !dst_len);
 970
 971                 if (bch2_csum_type_is_encryption(op->csum_type)) {
 972                         if (bversion_zero(version)) {
 973                                 version.lo = atomic64_inc_return(&c->key_version);
 974                         } else {
 975                                 crc.nonce = op->nonce;
 976                                 op->nonce += src_len >> 9;
 977                         }
 978                 }
 979
 980                 if ((op->flags & BCH_WRITE_DATA_ENCODED) &&
 981                     !crc_is_compressed(crc) &&
 982                     bch2_csum_type_is_encryption(op->crc.csum_type) ==
 983                     bch2_csum_type_is_encryption(op->csum_type)) {
 984                         u8 compression_type = crc.compression_type;
 985                         u16 nonce = crc.nonce;
 986                         /*
 987                          * Note: when we're using rechecksum(), we need to be
 988                          * checksumming @src because it has all the data our
 989                          * existing checksum covers - if we bounced (because we
 990                          * were trying to compress), @dst will only have the
 991                          * part of the data the new checksum will cover.
 992                          *
 993                          * But normally we want to be checksumming post bounce,
 994                          * because part of the reason for bouncing is so the
 995                          * data can't be modified (by userspace) while it's in
 996                          * flight.
 997                          */
 998                         if (bch2_rechecksum_bio(c, src, version, op->crc,
 999                                         &crc, &op->crc,
1000                                         src_len >> 9,
1001                                         bio_sectors(src) - (src_len >> 9),
1002                                         op->csum_type))
1003                                 goto csum_err;
1004                         /*
1005                          * rchecksum_bio sets compression_type on crc from op->crc,
1006                          * this isn't always correct as sometimes we're changing
1007                          * an extent from uncompressed to incompressible.
1008                          */
1009                         crc.compression_type = compression_type;
1010                         crc.nonce = nonce;
1011                 } else {
1012                         if ((op->flags & BCH_WRITE_DATA_ENCODED) &&
1013                             bch2_rechecksum_bio(c, src, version, op->crc,
1014                                         NULL, &op->crc,
1015                                         src_len >> 9,
1016                                         bio_sectors(src) - (src_len >> 9),
1017                                         op->crc.csum_type))
1018                                 goto csum_err;
1019
1020                         crc.compressed_size     = dst_len >> 9;
1021                         crc.uncompressed_size   = src_len >> 9;
1022                         crc.live_size           = src_len >> 9;
1023
1024                         swap(dst->bi_iter.bi_size, dst_len);
1025                         ret = bch2_encrypt_bio(c, op->csum_type,
1026                                                extent_nonce(version, crc), dst);
1027                         if (ret)
1028                                 goto err;
1029
1030                         crc.csum = bch2_checksum_bio(c, op->csum_type,
1031                                          extent_nonce(version, crc), dst);
1032                         crc.csum_type = op->csum_type;
1033                         swap(dst->bi_iter.bi_size, dst_len);
1034                 }
1035
1036                 init_append_extent(op, wp, version, crc);
1037
1038                 if (dst != src)
1039                         bio_advance(dst, dst_len);
1040                 bio_advance(src, src_len);
1041                 total_output    += dst_len;
1042                 total_input     += src_len;
1043         } while (dst->bi_iter.bi_size &&
1044                  src->bi_iter.bi_size &&
1045                  wp->sectors_free &&
1046                  !bch2_keylist_realloc(&op->insert_keys,
1047                                       op->inline_keys,
1048                                       ARRAY_SIZE(op->inline_keys),
1049                                       BKEY_EXTENT_U64s_MAX));
1050
1051         more = src->bi_iter.bi_size != 0;
1052
1053         dst->bi_iter = saved_iter;
1054
1055         if (dst == src && more) {
1056                 BUG_ON(total_output != total_input);
1057
1058                 dst = bio_split(src, total_input >> 9,
1059                                 GFP_NOFS, &c->bio_write);
1060                 wbio_init(dst)->put_bio = true;
1061                 /* copy WRITE_SYNC flag */
1062                 dst->bi_opf             = src->bi_opf;
1063         }
1064
1065         dst->bi_iter.bi_size = total_output;
1066 do_write:
1067         *_dst = dst;
1068         return more;
1069 csum_err:
1070         bch_err(c, "error verifying existing checksum while rewriting existing data (memory corruption?)");
1071         ret = -EIO;
1072 err:
1073         if (to_wbio(dst)->bounce)
1074                 bch2_bio_free_pages_pool(c, dst);
1075         if (to_wbio(dst)->put_bio)
1076                 bio_put(dst);
1077
1078         return ret;
1079 }
1080
1081 static bool bch2_extent_is_writeable(struct bch_write_op *op,
1082                                      struct bkey_s_c k)
1083 {
1084         struct bch_fs *c = op->c;
1085         struct bkey_s_c_extent e;
1086         struct extent_ptr_decoded p;
1087         const union bch_extent_entry *entry;
1088         unsigned replicas = 0;
1089
1090         if (k.k->type != KEY_TYPE_extent)
1091                 return false;
1092
1093         e = bkey_s_c_to_extent(k);
1094         extent_for_each_ptr_decode(e, p, entry) {
1095                 if (crc_is_encoded(p.crc) || p.has_ec)
1096                         return false;
1097
1098                 replicas += bch2_extent_ptr_durability(c, &p);
1099         }
1100
1101         return replicas >= op->opts.data_replicas;
1102 }
1103
1104 static inline void bch2_nocow_write_unlock(struct bch_write_op *op)
1105 {
1106         struct bch_fs *c = op->c;
1107
1108         for_each_keylist_key(&op->insert_keys, k) {
1109                 struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(bkey_i_to_s_c(k));
1110
1111                 bkey_for_each_ptr(ptrs, ptr)
1112                         bch2_bucket_nocow_unlock(&c->nocow_locks,
1113                                                  PTR_BUCKET_POS(c, ptr),
1114                                                  BUCKET_NOCOW_LOCK_UPDATE);
1115         }
1116 }
1117
1118 static int bch2_nocow_write_convert_one_unwritten(struct btree_trans *trans,
1119                                                   struct btree_iter *iter,
1120                                                   struct bkey_i *orig,
1121                                                   struct bkey_s_c k,
1122                                                   u64 new_i_size)
1123 {
1124         if (!bch2_extents_match(bkey_i_to_s_c(orig), k)) {
1125                 /* trace this */
1126                 return 0;
1127         }
1128
1129         struct bkey_i *new = bch2_bkey_make_mut_noupdate(trans, k);
1130         int ret = PTR_ERR_OR_ZERO(new);
1131         if (ret)
1132                 return ret;
1133
1134         bch2_cut_front(bkey_start_pos(&orig->k), new);
1135         bch2_cut_back(orig->k.p, new);
1136
1137         struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
1138         bkey_for_each_ptr(ptrs, ptr)
1139                 ptr->unwritten = 0;
1140
1141         /*
1142          * Note that we're not calling bch2_subvol_get_snapshot() in this path -
1143          * that was done when we kicked off the write, and here it's important
1144          * that we update the extent that we wrote to - even if a snapshot has
1145          * since been created. The write is still outstanding, so we're ok
1146          * w.r.t. snapshot atomicity:
1147          */
1148         return  bch2_extent_update_i_size_sectors(trans, iter,
1149                                         min(new->k.p.offset << 9, new_i_size), 0) ?:
1150                 bch2_trans_update(trans, iter, new,
1151                                   BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
1152 }
1153
1154 static void bch2_nocow_write_convert_unwritten(struct bch_write_op *op)
1155 {
1156         struct bch_fs *c = op->c;
1157         struct btree_trans *trans = bch2_trans_get(c);
1158
1159         for_each_keylist_key(&op->insert_keys, orig) {
1160                 int ret = for_each_btree_key_upto_commit(trans, iter, BTREE_ID_extents,
1161                                      bkey_start_pos(&orig->k), orig->k.p,
1162                                      BTREE_ITER_INTENT, k,
1163                                      NULL, NULL, BCH_TRANS_COMMIT_no_enospc, ({
1164                         bch2_nocow_write_convert_one_unwritten(trans, &iter, orig, k, op->new_i_size);
1165                 }));
1166
1167                 if (ret && !bch2_err_matches(ret, EROFS)) {
1168                         struct bkey_i *insert = bch2_keylist_front(&op->insert_keys);
1169
1170                         bch_err_inum_offset_ratelimited(c,
1171                                 insert->k.p.inode, insert->k.p.offset << 9,
1172                                 "write error while doing btree update: %s",
1173                                 bch2_err_str(ret));
1174                 }
1175
1176                 if (ret) {
1177                         op->error = ret;
1178                         break;
1179                 }
1180         }
1181
1182         bch2_trans_put(trans);
1183 }
1184
1185 static void __bch2_nocow_write_done(struct bch_write_op *op)
1186 {
1187         bch2_nocow_write_unlock(op);
1188
1189         if (unlikely(op->flags & BCH_WRITE_IO_ERROR)) {
1190                 op->error = -EIO;
1191         } else if (unlikely(op->flags & BCH_WRITE_CONVERT_UNWRITTEN))
1192                 bch2_nocow_write_convert_unwritten(op);
1193 }
1194
1195 static CLOSURE_CALLBACK(bch2_nocow_write_done)
1196 {
1197         closure_type(op, struct bch_write_op, cl);
1198
1199         __bch2_nocow_write_done(op);
1200         bch2_write_done(cl);
1201 }
1202
1203 struct bucket_to_lock {
1204         struct bpos             b;
1205         unsigned                gen;
1206         struct nocow_lock_bucket *l;
1207 };
1208
1209 static void bch2_nocow_write(struct bch_write_op *op)
1210 {
1211         struct bch_fs *c = op->c;
1212         struct btree_trans *trans;
1213         struct btree_iter iter;
1214         struct bkey_s_c k;
1215         DARRAY_PREALLOCATED(struct bucket_to_lock, 3) buckets;
1216         u32 snapshot;
1217         struct bucket_to_lock *stale_at;
1218         int ret;
1219
1220         if (op->flags & BCH_WRITE_MOVE)
1221                 return;
1222
1223         darray_init(&buckets);
1224         trans = bch2_trans_get(c);
1225 retry:
1226         bch2_trans_begin(trans);
1227
1228         ret = bch2_subvolume_get_snapshot(trans, op->subvol, &snapshot);
1229         if (unlikely(ret))
1230                 goto err;
1231
1232         bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
1233                              SPOS(op->pos.inode, op->pos.offset, snapshot),
1234                              BTREE_ITER_SLOTS);
1235         while (1) {
1236                 struct bio *bio = &op->wbio.bio;
1237
1238                 buckets.nr = 0;
1239
1240                 k = bch2_btree_iter_peek_slot(&iter);
1241                 ret = bkey_err(k);
1242                 if (ret)
1243                         break;
1244
1245                 /* fall back to normal cow write path? */
1246                 if (unlikely(k.k->p.snapshot != snapshot ||
1247                              !bch2_extent_is_writeable(op, k)))
1248                         break;
1249
1250                 if (bch2_keylist_realloc(&op->insert_keys,
1251                                          op->inline_keys,
1252                                          ARRAY_SIZE(op->inline_keys),
1253                                          k.k->u64s))
1254                         break;
1255
1256                 /* Get iorefs before dropping btree locks: */
1257                 struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
1258                 bkey_for_each_ptr(ptrs, ptr) {
1259                         struct bpos b = PTR_BUCKET_POS(c, ptr);
1260                         struct nocow_lock_bucket *l =
1261                                 bucket_nocow_lock(&c->nocow_locks, bucket_to_u64(b));
1262                         prefetch(l);
1263
1264                         if (unlikely(!bch2_dev_get_ioref(bch_dev_bkey_exists(c, ptr->dev), WRITE)))
1265                                 goto err_get_ioref;
1266
1267                         /* XXX allocating memory with btree locks held - rare */
1268                         darray_push_gfp(&buckets, ((struct bucket_to_lock) {
1269                                                    .b = b, .gen = ptr->gen, .l = l,
1270                                                    }), GFP_KERNEL|__GFP_NOFAIL);
1271
1272                         if (ptr->unwritten)
1273                                 op->flags |= BCH_WRITE_CONVERT_UNWRITTEN;
1274                 }
1275
1276                 /* Unlock before taking nocow locks, doing IO: */
1277                 bkey_reassemble(op->insert_keys.top, k);
1278                 bch2_trans_unlock(trans);
1279
1280                 bch2_cut_front(op->pos, op->insert_keys.top);
1281                 if (op->flags & BCH_WRITE_CONVERT_UNWRITTEN)
1282                         bch2_cut_back(POS(op->pos.inode, op->pos.offset + bio_sectors(bio)), op->insert_keys.top);
1283
1284                 darray_for_each(buckets, i) {
1285                         struct bch_dev *ca = bch_dev_bkey_exists(c, i->b.inode);
1286
1287                         __bch2_bucket_nocow_lock(&c->nocow_locks, i->l,
1288                                                  bucket_to_u64(i->b),
1289                                                  BUCKET_NOCOW_LOCK_UPDATE);
1290
1291                         rcu_read_lock();
1292                         bool stale = gen_after(*bucket_gen(ca, i->b.offset), i->gen);
1293                         rcu_read_unlock();
1294
1295                         if (unlikely(stale)) {
1296                                 stale_at = i;
1297                                 goto err_bucket_stale;
1298                         }
1299                 }
1300
1301                 bio = &op->wbio.bio;
1302                 if (k.k->p.offset < op->pos.offset + bio_sectors(bio)) {
1303                         bio = bio_split(bio, k.k->p.offset - op->pos.offset,
1304                                         GFP_KERNEL, &c->bio_write);
1305                         wbio_init(bio)->put_bio = true;
1306                         bio->bi_opf = op->wbio.bio.bi_opf;
1307                 } else {
1308                         op->flags |= BCH_WRITE_DONE;
1309                 }
1310
1311                 op->pos.offset += bio_sectors(bio);
1312                 op->written += bio_sectors(bio);
1313
1314                 bio->bi_end_io  = bch2_write_endio;
1315                 bio->bi_private = &op->cl;
1316                 bio->bi_opf |= REQ_OP_WRITE;
1317                 closure_get(&op->cl);
1318                 bch2_submit_wbio_replicas(to_wbio(bio), c, BCH_DATA_user,
1319                                           op->insert_keys.top, true);
1320
1321                 bch2_keylist_push(&op->insert_keys);
1322                 if (op->flags & BCH_WRITE_DONE)
1323                         break;
1324                 bch2_btree_iter_advance(&iter);
1325         }
1326 out:
1327         bch2_trans_iter_exit(trans, &iter);
1328 err:
1329         if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
1330                 goto retry;
1331
1332         if (ret) {
1333                 bch_err_inum_offset_ratelimited(c,
1334                         op->pos.inode, op->pos.offset << 9,
1335                         "%s: btree lookup error %s", __func__, bch2_err_str(ret));
1336                 op->error = ret;
1337                 op->flags |= BCH_WRITE_DONE;
1338         }
1339
1340         bch2_trans_put(trans);
1341         darray_exit(&buckets);
1342
1343         /* fallback to cow write path? */
1344         if (!(op->flags & BCH_WRITE_DONE)) {
1345                 closure_sync(&op->cl);
1346                 __bch2_nocow_write_done(op);
1347                 op->insert_keys.top = op->insert_keys.keys;
1348         } else if (op->flags & BCH_WRITE_SYNC) {
1349                 closure_sync(&op->cl);
1350                 bch2_nocow_write_done(&op->cl.work);
1351         } else {
1352                 /*
1353                  * XXX
1354                  * needs to run out of process context because ei_quota_lock is
1355                  * a mutex
1356                  */
1357                 continue_at(&op->cl, bch2_nocow_write_done, index_update_wq(op));
1358         }
1359         return;
1360 err_get_ioref:
1361         darray_for_each(buckets, i)
1362                 percpu_ref_put(&bch_dev_bkey_exists(c, i->b.inode)->io_ref);
1363
1364         /* Fall back to COW path: */
1365         goto out;
1366 err_bucket_stale:
1367         darray_for_each(buckets, i) {
1368                 bch2_bucket_nocow_unlock(&c->nocow_locks, i->b, BUCKET_NOCOW_LOCK_UPDATE);
1369                 if (i == stale_at)
1370                         break;
1371         }
1372
1373         /* We can retry this: */
1374         ret = -BCH_ERR_transaction_restart;
1375         goto err_get_ioref;
1376 }
1377
1378 static void __bch2_write(struct bch_write_op *op)
1379 {
1380         struct bch_fs *c = op->c;
1381         struct write_point *wp = NULL;
1382         struct bio *bio = NULL;
1383         unsigned nofs_flags;
1384         int ret;
1385
1386         nofs_flags = memalloc_nofs_save();
1387
1388         if (unlikely(op->opts.nocow && c->opts.nocow_enabled)) {
1389                 bch2_nocow_write(op);
1390                 if (op->flags & BCH_WRITE_DONE)
1391                         goto out_nofs_restore;
1392         }
1393 again:
1394         memset(&op->failed, 0, sizeof(op->failed));
1395
1396         do {
1397                 struct bkey_i *key_to_write;
1398                 unsigned key_to_write_offset = op->insert_keys.top_p -
1399                         op->insert_keys.keys_p;
1400
1401                 /* +1 for possible cache device: */
1402                 if (op->open_buckets.nr + op->nr_replicas + 1 >
1403                     ARRAY_SIZE(op->open_buckets.v))
1404                         break;
1405
1406                 if (bch2_keylist_realloc(&op->insert_keys,
1407                                         op->inline_keys,
1408                                         ARRAY_SIZE(op->inline_keys),
1409                                         BKEY_EXTENT_U64s_MAX))
1410                         break;
1411
1412                 /*
1413                  * The copygc thread is now global, which means it's no longer
1414                  * freeing up space on specific disks, which means that
1415                  * allocations for specific disks may hang arbitrarily long:
1416                  */
1417                 ret = bch2_trans_do(c, NULL, NULL, 0,
1418                         bch2_alloc_sectors_start_trans(trans,
1419                                 op->target,
1420                                 op->opts.erasure_code && !(op->flags & BCH_WRITE_CACHED),
1421                                 op->write_point,
1422                                 &op->devs_have,
1423                                 op->nr_replicas,
1424                                 op->nr_replicas_required,
1425                                 op->watermark,
1426                                 op->flags,
1427                                 (op->flags & (BCH_WRITE_ALLOC_NOWAIT|
1428                                               BCH_WRITE_ONLY_SPECIFIED_DEVS))
1429                                 ? NULL : &op->cl, &wp));
1430                 if (unlikely(ret)) {
1431                         if (bch2_err_matches(ret, BCH_ERR_operation_blocked))
1432                                 break;
1433
1434                         goto err;
1435                 }
1436
1437                 EBUG_ON(!wp);
1438
1439                 bch2_open_bucket_get(c, wp, &op->open_buckets);
1440                 ret = bch2_write_extent(op, wp, &bio);
1441
1442                 bch2_alloc_sectors_done_inlined(c, wp);
1443 err:
1444                 if (ret <= 0) {
1445                         op->flags |= BCH_WRITE_DONE;
1446
1447                         if (ret < 0) {
1448                                 if (!(op->flags & BCH_WRITE_ALLOC_NOWAIT))
1449                                         bch_err_inum_offset_ratelimited(c,
1450                                                 op->pos.inode,
1451                                                 op->pos.offset << 9,
1452                                                 "%s(): error: %s", __func__, bch2_err_str(ret));
1453                                 op->error = ret;
1454                                 break;
1455                         }
1456                 }
1457
1458                 bio->bi_end_io  = bch2_write_endio;
1459                 bio->bi_private = &op->cl;
1460                 bio->bi_opf |= REQ_OP_WRITE;
1461
1462                 closure_get(bio->bi_private);
1463
1464                 key_to_write = (void *) (op->insert_keys.keys_p +
1465                                          key_to_write_offset);
1466
1467                 bch2_submit_wbio_replicas(to_wbio(bio), c, BCH_DATA_user,
1468                                           key_to_write, false);
1469         } while (ret);
1470
1471         /*
1472          * Sync or no?
1473          *
1474          * If we're running asynchronously, wne may still want to block
1475          * synchronously here if we weren't able to submit all of the IO at
1476          * once, as that signals backpressure to the caller.
1477          */
1478         if ((op->flags & BCH_WRITE_SYNC) ||
1479             (!(op->flags & BCH_WRITE_DONE) &&
1480              !(op->flags & BCH_WRITE_IN_WORKER))) {
1481                 closure_sync(&op->cl);
1482                 __bch2_write_index(op);
1483
1484                 if (!(op->flags & BCH_WRITE_DONE))
1485                         goto again;
1486                 bch2_write_done(&op->cl);
1487         } else {
1488                 bch2_write_queue(op, wp);
1489                 continue_at(&op->cl, bch2_write_index, NULL);
1490         }
1491 out_nofs_restore:
1492         memalloc_nofs_restore(nofs_flags);
1493 }
1494
1495 static void bch2_write_data_inline(struct bch_write_op *op, unsigned data_len)
1496 {
1497         struct bio *bio = &op->wbio.bio;
1498         struct bvec_iter iter;
1499         struct bkey_i_inline_data *id;
1500         unsigned sectors;
1501         int ret;
1502
1503         op->flags |= BCH_WRITE_WROTE_DATA_INLINE;
1504         op->flags |= BCH_WRITE_DONE;
1505
1506         bch2_check_set_feature(op->c, BCH_FEATURE_inline_data);
1507
1508         ret = bch2_keylist_realloc(&op->insert_keys, op->inline_keys,
1509                                    ARRAY_SIZE(op->inline_keys),
1510                                    BKEY_U64s + DIV_ROUND_UP(data_len, 8));
1511         if (ret) {
1512                 op->error = ret;
1513                 goto err;
1514         }
1515
1516         sectors = bio_sectors(bio);
1517         op->pos.offset += sectors;
1518
1519         id = bkey_inline_data_init(op->insert_keys.top);
1520         id->k.p         = op->pos;
1521         id->k.version   = op->version;
1522         id->k.size      = sectors;
1523
1524         iter = bio->bi_iter;
1525         iter.bi_size = data_len;
1526         memcpy_from_bio(id->v.data, bio, iter);
1527
1528         while (data_len & 7)
1529                 id->v.data[data_len++] = '\0';
1530         set_bkey_val_bytes(&id->k, data_len);
1531         bch2_keylist_push(&op->insert_keys);
1532
1533         __bch2_write_index(op);
1534 err:
1535         bch2_write_done(&op->cl);
1536 }
1537
1538 /**
1539  * bch2_write() - handle a write to a cache device or flash only volume
1540  * @cl:         &bch_write_op->cl
1541  *
1542  * This is the starting point for any data to end up in a cache device; it could
1543  * be from a normal write, or a writeback write, or a write to a flash only
1544  * volume - it's also used by the moving garbage collector to compact data in
1545  * mostly empty buckets.
1546  *
1547  * It first writes the data to the cache, creating a list of keys to be inserted
1548  * (if the data won't fit in a single open bucket, there will be multiple keys);
1549  * after the data is written it calls bch_journal, and after the keys have been
1550  * added to the next journal write they're inserted into the btree.
1551  *
1552  * If op->discard is true, instead of inserting the data it invalidates the
1553  * region of the cache represented by op->bio and op->inode.
1554  */
1555 CLOSURE_CALLBACK(bch2_write)
1556 {
1557         closure_type(op, struct bch_write_op, cl);
1558         struct bio *bio = &op->wbio.bio;
1559         struct bch_fs *c = op->c;
1560         unsigned data_len;
1561
1562         EBUG_ON(op->cl.parent);
1563         BUG_ON(!op->nr_replicas);
1564         BUG_ON(!op->write_point.v);
1565         BUG_ON(bkey_eq(op->pos, POS_MAX));
1566
1567         op->start_time = local_clock();
1568         bch2_keylist_init(&op->insert_keys, op->inline_keys);
1569         wbio_init(bio)->put_bio = false;
1570
1571         if (bio->bi_iter.bi_size & (c->opts.block_size - 1)) {
1572                 bch_err_inum_offset_ratelimited(c,
1573                         op->pos.inode,
1574                         op->pos.offset << 9,
1575                         "misaligned write");
1576                 op->error = -EIO;
1577                 goto err;
1578         }
1579
1580         if (c->opts.nochanges) {
1581                 op->error = -BCH_ERR_erofs_no_writes;
1582                 goto err;
1583         }
1584
1585         if (!(op->flags & BCH_WRITE_MOVE) &&
1586             !bch2_write_ref_tryget(c, BCH_WRITE_REF_write)) {
1587                 op->error = -BCH_ERR_erofs_no_writes;
1588                 goto err;
1589         }
1590
1591         this_cpu_add(c->counters[BCH_COUNTER_io_write], bio_sectors(bio));
1592         bch2_increment_clock(c, bio_sectors(bio), WRITE);
1593
1594         data_len = min_t(u64, bio->bi_iter.bi_size,
1595                          op->new_i_size - (op->pos.offset << 9));
1596
1597         if (c->opts.inline_data &&
1598             data_len <= min(block_bytes(c) / 2, 1024U)) {
1599                 bch2_write_data_inline(op, data_len);
1600                 return;
1601         }
1602
1603         __bch2_write(op);
1604         return;
1605 err:
1606         bch2_disk_reservation_put(c, &op->res);
1607
1608         closure_debug_destroy(&op->cl);
1609         if (op->end_io)
1610                 op->end_io(op);
1611 }
1612
1613 static const char * const bch2_write_flags[] = {
1614 #define x(f)    #f,
1615         BCH_WRITE_FLAGS()
1616 #undef x
1617         NULL
1618 };
1619
1620 void bch2_write_op_to_text(struct printbuf *out, struct bch_write_op *op)
1621 {
1622         prt_str(out, "pos: ");
1623         bch2_bpos_to_text(out, op->pos);
1624         prt_newline(out);
1625         printbuf_indent_add(out, 2);
1626
1627         prt_str(out, "started: ");
1628         bch2_pr_time_units(out, local_clock() - op->start_time);
1629         prt_newline(out);
1630
1631         prt_str(out, "flags: ");
1632         prt_bitflags(out, bch2_write_flags, op->flags);
1633         prt_newline(out);
1634
1635         prt_printf(out, "ref: %u", closure_nr_remaining(&op->cl));
1636         prt_newline(out);
1637
1638         printbuf_indent_sub(out, 2);
1639 }
1640
1641 void bch2_fs_io_write_exit(struct bch_fs *c)
1642 {
1643         mempool_exit(&c->bio_bounce_pages);
1644         bioset_exit(&c->bio_write);
1645 }
1646
1647 int bch2_fs_io_write_init(struct bch_fs *c)
1648 {
1649         if (bioset_init(&c->bio_write, 1, offsetof(struct bch_write_bio, bio),
1650                         BIOSET_NEED_BVECS))
1651                 return -BCH_ERR_ENOMEM_bio_write_init;
1652
1653         if (mempool_init_page_pool(&c->bio_bounce_pages,
1654                                    max_t(unsigned,
1655                                          c->opts.btree_node_size,
1656                                          c->opts.encoded_extent_max) /
1657                                    PAGE_SIZE, 0))
1658                 return -BCH_ERR_ENOMEM_bio_bounce_pages_init;
1659
1660         return 0;
1661 }