xref: /linux/fs/bcachefs/io_write.c (revision 90d32e92011eaae8e70a9169b4e7acf4ca8f9d3a)
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 	__bch2_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 	/*
203 	 * Crazy performance optimization:
204 	 * Every extent update needs to also update the inode: the inode trigger
205 	 * will set bi->journal_seq to the journal sequence number of this
206 	 * transaction - for fsync.
207 	 *
208 	 * But if that's the only reason we're updating the inode (we're not
209 	 * updating bi_size or bi_sectors), then we don't need the inode update
210 	 * to be journalled - if we crash, the bi_journal_seq update will be
211 	 * lost, but that's fine.
212 	 */
213 	unsigned inode_update_flags = BTREE_UPDATE_nojournal;
214 
215 	struct btree_iter iter;
216 	struct bkey_s_c k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_inodes,
217 			      SPOS(0,
218 				   extent_iter->pos.inode,
219 				   extent_iter->snapshot),
220 			      BTREE_ITER_cached);
221 	int ret = bkey_err(k);
222 	if (unlikely(ret))
223 		return ret;
224 
225 	/*
226 	 * varint_decode_fast(), in the inode .invalid method, reads up to 7
227 	 * bytes past the end of the buffer:
228 	 */
229 	struct bkey_i *k_mut = bch2_trans_kmalloc_nomemzero(trans, bkey_bytes(k.k) + 8);
230 	ret = PTR_ERR_OR_ZERO(k_mut);
231 	if (unlikely(ret))
232 		goto err;
233 
234 	bkey_reassemble(k_mut, k);
235 
236 	if (unlikely(k_mut->k.type != KEY_TYPE_inode_v3)) {
237 		k_mut = bch2_inode_to_v3(trans, k_mut);
238 		ret = PTR_ERR_OR_ZERO(k_mut);
239 		if (unlikely(ret))
240 			goto err;
241 	}
242 
243 	struct bkey_i_inode_v3 *inode = bkey_i_to_inode_v3(k_mut);
244 
245 	if (!(le64_to_cpu(inode->v.bi_flags) & BCH_INODE_i_size_dirty) &&
246 	    new_i_size > le64_to_cpu(inode->v.bi_size)) {
247 		inode->v.bi_size = cpu_to_le64(new_i_size);
248 		inode_update_flags = 0;
249 	}
250 
251 	if (i_sectors_delta) {
252 		le64_add_cpu(&inode->v.bi_sectors, i_sectors_delta);
253 		inode_update_flags = 0;
254 	}
255 
256 	if (inode->k.p.snapshot != iter.snapshot) {
257 		inode->k.p.snapshot = iter.snapshot;
258 		inode_update_flags = 0;
259 	}
260 
261 	ret = bch2_trans_update(trans, &iter, &inode->k_i,
262 				BTREE_UPDATE_internal_snapshot_node|
263 				inode_update_flags);
264 err:
265 	bch2_trans_iter_exit(trans, &iter);
266 	return ret;
267 }
268 
269 int bch2_extent_update(struct btree_trans *trans,
270 		       subvol_inum inum,
271 		       struct btree_iter *iter,
272 		       struct bkey_i *k,
273 		       struct disk_reservation *disk_res,
274 		       u64 new_i_size,
275 		       s64 *i_sectors_delta_total,
276 		       bool check_enospc)
277 {
278 	struct bpos next_pos;
279 	bool usage_increasing;
280 	s64 i_sectors_delta = 0, disk_sectors_delta = 0;
281 	int ret;
282 
283 	/*
284 	 * This traverses us the iterator without changing iter->path->pos to
285 	 * search_key() (which is pos + 1 for extents): we want there to be a
286 	 * path already traversed at iter->pos because
287 	 * bch2_trans_extent_update() will use it to attempt extent merging
288 	 */
289 	ret = __bch2_btree_iter_traverse(iter);
290 	if (ret)
291 		return ret;
292 
293 	ret = bch2_extent_trim_atomic(trans, iter, k);
294 	if (ret)
295 		return ret;
296 
297 	next_pos = k->k.p;
298 
299 	ret = bch2_sum_sector_overwrites(trans, iter, k,
300 			&usage_increasing,
301 			&i_sectors_delta,
302 			&disk_sectors_delta);
303 	if (ret)
304 		return ret;
305 
306 	if (disk_res &&
307 	    disk_sectors_delta > (s64) disk_res->sectors) {
308 		ret = bch2_disk_reservation_add(trans->c, disk_res,
309 					disk_sectors_delta - disk_res->sectors,
310 					!check_enospc || !usage_increasing
311 					? BCH_DISK_RESERVATION_NOFAIL : 0);
312 		if (ret)
313 			return ret;
314 	}
315 
316 	/*
317 	 * Note:
318 	 * We always have to do an inode update - even when i_size/i_sectors
319 	 * aren't changing - for fsync to work properly; fsync relies on
320 	 * inode->bi_journal_seq which is updated by the trigger code:
321 	 */
322 	ret =   bch2_extent_update_i_size_sectors(trans, iter,
323 						  min(k->k.p.offset << 9, new_i_size),
324 						  i_sectors_delta) ?:
325 		bch2_trans_update(trans, iter, k, 0) ?:
326 		bch2_trans_commit(trans, disk_res, NULL,
327 				BCH_TRANS_COMMIT_no_check_rw|
328 				BCH_TRANS_COMMIT_no_enospc);
329 	if (unlikely(ret))
330 		return ret;
331 
332 	if (i_sectors_delta_total)
333 		*i_sectors_delta_total += i_sectors_delta;
334 	bch2_btree_iter_set_pos(iter, next_pos);
335 	return 0;
336 }
337 
338 static int bch2_write_index_default(struct bch_write_op *op)
339 {
340 	struct bch_fs *c = op->c;
341 	struct bkey_buf sk;
342 	struct keylist *keys = &op->insert_keys;
343 	struct bkey_i *k = bch2_keylist_front(keys);
344 	struct btree_trans *trans = bch2_trans_get(c);
345 	struct btree_iter iter;
346 	subvol_inum inum = {
347 		.subvol = op->subvol,
348 		.inum	= k->k.p.inode,
349 	};
350 	int ret;
351 
352 	BUG_ON(!inum.subvol);
353 
354 	bch2_bkey_buf_init(&sk);
355 
356 	do {
357 		bch2_trans_begin(trans);
358 
359 		k = bch2_keylist_front(keys);
360 		bch2_bkey_buf_copy(&sk, c, k);
361 
362 		ret = bch2_subvolume_get_snapshot(trans, inum.subvol,
363 						  &sk.k->k.p.snapshot);
364 		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
365 			continue;
366 		if (ret)
367 			break;
368 
369 		bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
370 				     bkey_start_pos(&sk.k->k),
371 				     BTREE_ITER_slots|BTREE_ITER_intent);
372 
373 		ret =   bch2_bkey_set_needs_rebalance(c, sk.k, &op->opts) ?:
374 			bch2_extent_update(trans, inum, &iter, sk.k,
375 					&op->res,
376 					op->new_i_size, &op->i_sectors_delta,
377 					op->flags & BCH_WRITE_CHECK_ENOSPC);
378 		bch2_trans_iter_exit(trans, &iter);
379 
380 		if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
381 			continue;
382 		if (ret)
383 			break;
384 
385 		if (bkey_ge(iter.pos, k->k.p))
386 			bch2_keylist_pop_front(&op->insert_keys);
387 		else
388 			bch2_cut_front(iter.pos, k);
389 	} while (!bch2_keylist_empty(keys));
390 
391 	bch2_trans_put(trans);
392 	bch2_bkey_buf_exit(&sk, c);
393 
394 	return ret;
395 }
396 
397 /* Writes */
398 
399 void bch2_submit_wbio_replicas(struct bch_write_bio *wbio, struct bch_fs *c,
400 			       enum bch_data_type type,
401 			       const struct bkey_i *k,
402 			       bool nocow)
403 {
404 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(bkey_i_to_s_c(k));
405 	struct bch_write_bio *n;
406 
407 	BUG_ON(c->opts.nochanges);
408 
409 	bkey_for_each_ptr(ptrs, ptr) {
410 		struct bch_dev *ca = nocow
411 			? bch2_dev_have_ref(c, ptr->dev)
412 			: bch2_dev_get_ioref(c, ptr->dev, type == BCH_DATA_btree ? READ : WRITE);
413 
414 		if (to_entry(ptr + 1) < ptrs.end) {
415 			n = to_wbio(bio_alloc_clone(NULL, &wbio->bio, GFP_NOFS, &c->replica_set));
416 
417 			n->bio.bi_end_io	= wbio->bio.bi_end_io;
418 			n->bio.bi_private	= wbio->bio.bi_private;
419 			n->parent		= wbio;
420 			n->split		= true;
421 			n->bounce		= false;
422 			n->put_bio		= true;
423 			n->bio.bi_opf		= wbio->bio.bi_opf;
424 			bio_inc_remaining(&wbio->bio);
425 		} else {
426 			n = wbio;
427 			n->split		= false;
428 		}
429 
430 		n->c			= c;
431 		n->dev			= ptr->dev;
432 		n->have_ioref		= ca != NULL;
433 		n->nocow		= nocow;
434 		n->submit_time		= local_clock();
435 		n->inode_offset		= bkey_start_offset(&k->k);
436 		if (nocow)
437 			n->nocow_bucket	= PTR_BUCKET_NR(ca, ptr);
438 		n->bio.bi_iter.bi_sector = ptr->offset;
439 
440 		if (likely(n->have_ioref)) {
441 			this_cpu_add(ca->io_done->sectors[WRITE][type],
442 				     bio_sectors(&n->bio));
443 
444 			bio_set_dev(&n->bio, ca->disk_sb.bdev);
445 
446 			if (type != BCH_DATA_btree && unlikely(c->opts.no_data_io)) {
447 				bio_endio(&n->bio);
448 				continue;
449 			}
450 
451 			submit_bio(&n->bio);
452 		} else {
453 			n->bio.bi_status	= BLK_STS_REMOVED;
454 			bio_endio(&n->bio);
455 		}
456 	}
457 }
458 
459 static void __bch2_write(struct bch_write_op *);
460 
461 static void bch2_write_done(struct closure *cl)
462 {
463 	struct bch_write_op *op = container_of(cl, struct bch_write_op, cl);
464 	struct bch_fs *c = op->c;
465 
466 	EBUG_ON(op->open_buckets.nr);
467 
468 	bch2_time_stats_update(&c->times[BCH_TIME_data_write], op->start_time);
469 	bch2_disk_reservation_put(c, &op->res);
470 
471 	if (!(op->flags & BCH_WRITE_MOVE))
472 		bch2_write_ref_put(c, BCH_WRITE_REF_write);
473 	bch2_keylist_free(&op->insert_keys, op->inline_keys);
474 
475 	EBUG_ON(cl->parent);
476 	closure_debug_destroy(cl);
477 	if (op->end_io)
478 		op->end_io(op);
479 }
480 
481 static noinline int bch2_write_drop_io_error_ptrs(struct bch_write_op *op)
482 {
483 	struct keylist *keys = &op->insert_keys;
484 	struct bkey_i *src, *dst = keys->keys, *n;
485 
486 	for (src = keys->keys; src != keys->top; src = n) {
487 		n = bkey_next(src);
488 
489 		if (bkey_extent_is_direct_data(&src->k)) {
490 			bch2_bkey_drop_ptrs(bkey_i_to_s(src), ptr,
491 					    test_bit(ptr->dev, op->failed.d));
492 
493 			if (!bch2_bkey_nr_ptrs(bkey_i_to_s_c(src)))
494 				return -EIO;
495 		}
496 
497 		if (dst != src)
498 			memmove_u64s_down(dst, src, src->k.u64s);
499 		dst = bkey_next(dst);
500 	}
501 
502 	keys->top = dst;
503 	return 0;
504 }
505 
506 /**
507  * __bch2_write_index - after a write, update index to point to new data
508  * @op:		bch_write_op to process
509  */
510 static void __bch2_write_index(struct bch_write_op *op)
511 {
512 	struct bch_fs *c = op->c;
513 	struct keylist *keys = &op->insert_keys;
514 	unsigned dev;
515 	int ret = 0;
516 
517 	if (unlikely(op->flags & BCH_WRITE_IO_ERROR)) {
518 		ret = bch2_write_drop_io_error_ptrs(op);
519 		if (ret)
520 			goto err;
521 	}
522 
523 	if (!bch2_keylist_empty(keys)) {
524 		u64 sectors_start = keylist_sectors(keys);
525 
526 		ret = !(op->flags & BCH_WRITE_MOVE)
527 			? bch2_write_index_default(op)
528 			: bch2_data_update_index_update(op);
529 
530 		BUG_ON(bch2_err_matches(ret, BCH_ERR_transaction_restart));
531 		BUG_ON(keylist_sectors(keys) && !ret);
532 
533 		op->written += sectors_start - keylist_sectors(keys);
534 
535 		if (ret && !bch2_err_matches(ret, EROFS)) {
536 			struct bkey_i *insert = bch2_keylist_front(&op->insert_keys);
537 
538 			bch_err_inum_offset_ratelimited(c,
539 				insert->k.p.inode, insert->k.p.offset << 9,
540 				"%s write error while doing btree update: %s",
541 				op->flags & BCH_WRITE_MOVE ? "move" : "user",
542 				bch2_err_str(ret));
543 		}
544 
545 		if (ret)
546 			goto err;
547 	}
548 out:
549 	/* If some a bucket wasn't written, we can't erasure code it: */
550 	for_each_set_bit(dev, op->failed.d, BCH_SB_MEMBERS_MAX)
551 		bch2_open_bucket_write_error(c, &op->open_buckets, dev);
552 
553 	bch2_open_buckets_put(c, &op->open_buckets);
554 	return;
555 err:
556 	keys->top = keys->keys;
557 	op->error = ret;
558 	op->flags |= BCH_WRITE_DONE;
559 	goto out;
560 }
561 
562 static inline void __wp_update_state(struct write_point *wp, enum write_point_state state)
563 {
564 	if (state != wp->state) {
565 		u64 now = ktime_get_ns();
566 
567 		if (wp->last_state_change &&
568 		    time_after64(now, wp->last_state_change))
569 			wp->time[wp->state] += now - wp->last_state_change;
570 		wp->state = state;
571 		wp->last_state_change = now;
572 	}
573 }
574 
575 static inline void wp_update_state(struct write_point *wp, bool running)
576 {
577 	enum write_point_state state;
578 
579 	state = running			 ? WRITE_POINT_running :
580 		!list_empty(&wp->writes) ? WRITE_POINT_waiting_io
581 					 : WRITE_POINT_stopped;
582 
583 	__wp_update_state(wp, state);
584 }
585 
586 static CLOSURE_CALLBACK(bch2_write_index)
587 {
588 	closure_type(op, struct bch_write_op, cl);
589 	struct write_point *wp = op->wp;
590 	struct workqueue_struct *wq = index_update_wq(op);
591 	unsigned long flags;
592 
593 	if ((op->flags & BCH_WRITE_DONE) &&
594 	    (op->flags & BCH_WRITE_MOVE))
595 		bch2_bio_free_pages_pool(op->c, &op->wbio.bio);
596 
597 	spin_lock_irqsave(&wp->writes_lock, flags);
598 	if (wp->state == WRITE_POINT_waiting_io)
599 		__wp_update_state(wp, WRITE_POINT_waiting_work);
600 	list_add_tail(&op->wp_list, &wp->writes);
601 	spin_unlock_irqrestore (&wp->writes_lock, flags);
602 
603 	queue_work(wq, &wp->index_update_work);
604 }
605 
606 static inline void bch2_write_queue(struct bch_write_op *op, struct write_point *wp)
607 {
608 	op->wp = wp;
609 
610 	if (wp->state == WRITE_POINT_stopped) {
611 		spin_lock_irq(&wp->writes_lock);
612 		__wp_update_state(wp, WRITE_POINT_waiting_io);
613 		spin_unlock_irq(&wp->writes_lock);
614 	}
615 }
616 
617 void bch2_write_point_do_index_updates(struct work_struct *work)
618 {
619 	struct write_point *wp =
620 		container_of(work, struct write_point, index_update_work);
621 	struct bch_write_op *op;
622 
623 	while (1) {
624 		spin_lock_irq(&wp->writes_lock);
625 		op = list_first_entry_or_null(&wp->writes, struct bch_write_op, wp_list);
626 		if (op)
627 			list_del(&op->wp_list);
628 		wp_update_state(wp, op != NULL);
629 		spin_unlock_irq(&wp->writes_lock);
630 
631 		if (!op)
632 			break;
633 
634 		op->flags |= BCH_WRITE_IN_WORKER;
635 
636 		__bch2_write_index(op);
637 
638 		if (!(op->flags & BCH_WRITE_DONE))
639 			__bch2_write(op);
640 		else
641 			bch2_write_done(&op->cl);
642 	}
643 }
644 
645 static void bch2_write_endio(struct bio *bio)
646 {
647 	struct closure *cl		= bio->bi_private;
648 	struct bch_write_op *op		= container_of(cl, struct bch_write_op, cl);
649 	struct bch_write_bio *wbio	= to_wbio(bio);
650 	struct bch_write_bio *parent	= wbio->split ? wbio->parent : NULL;
651 	struct bch_fs *c		= wbio->c;
652 	struct bch_dev *ca		= wbio->have_ioref
653 		? bch2_dev_have_ref(c, wbio->dev)
654 		: NULL;
655 
656 	if (bch2_dev_inum_io_err_on(bio->bi_status, ca, BCH_MEMBER_ERROR_write,
657 				    op->pos.inode,
658 				    wbio->inode_offset << 9,
659 				    "data write error: %s",
660 				    bch2_blk_status_to_str(bio->bi_status))) {
661 		set_bit(wbio->dev, op->failed.d);
662 		op->flags |= BCH_WRITE_IO_ERROR;
663 	}
664 
665 	if (wbio->nocow) {
666 		bch2_bucket_nocow_unlock(&c->nocow_locks,
667 					 POS(ca->dev_idx, wbio->nocow_bucket),
668 					 BUCKET_NOCOW_LOCK_UPDATE);
669 		set_bit(wbio->dev, op->devs_need_flush->d);
670 	}
671 
672 	if (wbio->have_ioref) {
673 		bch2_latency_acct(ca, wbio->submit_time, WRITE);
674 		percpu_ref_put(&ca->io_ref);
675 	}
676 
677 	if (wbio->bounce)
678 		bch2_bio_free_pages_pool(c, bio);
679 
680 	if (wbio->put_bio)
681 		bio_put(bio);
682 
683 	if (parent)
684 		bio_endio(&parent->bio);
685 	else
686 		closure_put(cl);
687 }
688 
689 static void init_append_extent(struct bch_write_op *op,
690 			       struct write_point *wp,
691 			       struct bversion version,
692 			       struct bch_extent_crc_unpacked crc)
693 {
694 	struct bkey_i_extent *e;
695 
696 	op->pos.offset += crc.uncompressed_size;
697 
698 	e = bkey_extent_init(op->insert_keys.top);
699 	e->k.p		= op->pos;
700 	e->k.size	= crc.uncompressed_size;
701 	e->k.version	= version;
702 
703 	if (crc.csum_type ||
704 	    crc.compression_type ||
705 	    crc.nonce)
706 		bch2_extent_crc_append(&e->k_i, crc);
707 
708 	bch2_alloc_sectors_append_ptrs_inlined(op->c, wp, &e->k_i, crc.compressed_size,
709 				       op->flags & BCH_WRITE_CACHED);
710 
711 	bch2_keylist_push(&op->insert_keys);
712 }
713 
714 static struct bio *bch2_write_bio_alloc(struct bch_fs *c,
715 					struct write_point *wp,
716 					struct bio *src,
717 					bool *page_alloc_failed,
718 					void *buf)
719 {
720 	struct bch_write_bio *wbio;
721 	struct bio *bio;
722 	unsigned output_available =
723 		min(wp->sectors_free << 9, src->bi_iter.bi_size);
724 	unsigned pages = DIV_ROUND_UP(output_available +
725 				      (buf
726 				       ? ((unsigned long) buf & (PAGE_SIZE - 1))
727 				       : 0), PAGE_SIZE);
728 
729 	pages = min(pages, BIO_MAX_VECS);
730 
731 	bio = bio_alloc_bioset(NULL, pages, 0,
732 			       GFP_NOFS, &c->bio_write);
733 	wbio			= wbio_init(bio);
734 	wbio->put_bio		= true;
735 	/* copy WRITE_SYNC flag */
736 	wbio->bio.bi_opf	= src->bi_opf;
737 
738 	if (buf) {
739 		bch2_bio_map(bio, buf, output_available);
740 		return bio;
741 	}
742 
743 	wbio->bounce		= true;
744 
745 	/*
746 	 * We can't use mempool for more than c->sb.encoded_extent_max
747 	 * worth of pages, but we'd like to allocate more if we can:
748 	 */
749 	bch2_bio_alloc_pages_pool(c, bio,
750 				  min_t(unsigned, output_available,
751 					c->opts.encoded_extent_max));
752 
753 	if (bio->bi_iter.bi_size < output_available)
754 		*page_alloc_failed =
755 			bch2_bio_alloc_pages(bio,
756 					     output_available -
757 					     bio->bi_iter.bi_size,
758 					     GFP_NOFS) != 0;
759 
760 	return bio;
761 }
762 
763 static int bch2_write_rechecksum(struct bch_fs *c,
764 				 struct bch_write_op *op,
765 				 unsigned new_csum_type)
766 {
767 	struct bio *bio = &op->wbio.bio;
768 	struct bch_extent_crc_unpacked new_crc;
769 	int ret;
770 
771 	/* bch2_rechecksum_bio() can't encrypt or decrypt data: */
772 
773 	if (bch2_csum_type_is_encryption(op->crc.csum_type) !=
774 	    bch2_csum_type_is_encryption(new_csum_type))
775 		new_csum_type = op->crc.csum_type;
776 
777 	ret = bch2_rechecksum_bio(c, bio, op->version, op->crc,
778 				  NULL, &new_crc,
779 				  op->crc.offset, op->crc.live_size,
780 				  new_csum_type);
781 	if (ret)
782 		return ret;
783 
784 	bio_advance(bio, op->crc.offset << 9);
785 	bio->bi_iter.bi_size = op->crc.live_size << 9;
786 	op->crc = new_crc;
787 	return 0;
788 }
789 
790 static int bch2_write_decrypt(struct bch_write_op *op)
791 {
792 	struct bch_fs *c = op->c;
793 	struct nonce nonce = extent_nonce(op->version, op->crc);
794 	struct bch_csum csum;
795 	int ret;
796 
797 	if (!bch2_csum_type_is_encryption(op->crc.csum_type))
798 		return 0;
799 
800 	/*
801 	 * If we need to decrypt data in the write path, we'll no longer be able
802 	 * to verify the existing checksum (poly1305 mac, in this case) after
803 	 * it's decrypted - this is the last point we'll be able to reverify the
804 	 * checksum:
805 	 */
806 	csum = bch2_checksum_bio(c, op->crc.csum_type, nonce, &op->wbio.bio);
807 	if (bch2_crc_cmp(op->crc.csum, csum) && !c->opts.no_data_io)
808 		return -EIO;
809 
810 	ret = bch2_encrypt_bio(c, op->crc.csum_type, nonce, &op->wbio.bio);
811 	op->crc.csum_type = 0;
812 	op->crc.csum = (struct bch_csum) { 0, 0 };
813 	return ret;
814 }
815 
816 static enum prep_encoded_ret {
817 	PREP_ENCODED_OK,
818 	PREP_ENCODED_ERR,
819 	PREP_ENCODED_CHECKSUM_ERR,
820 	PREP_ENCODED_DO_WRITE,
821 } bch2_write_prep_encoded_data(struct bch_write_op *op, struct write_point *wp)
822 {
823 	struct bch_fs *c = op->c;
824 	struct bio *bio = &op->wbio.bio;
825 
826 	if (!(op->flags & BCH_WRITE_DATA_ENCODED))
827 		return PREP_ENCODED_OK;
828 
829 	BUG_ON(bio_sectors(bio) != op->crc.compressed_size);
830 
831 	/* Can we just write the entire extent as is? */
832 	if (op->crc.uncompressed_size == op->crc.live_size &&
833 	    op->crc.uncompressed_size <= c->opts.encoded_extent_max >> 9 &&
834 	    op->crc.compressed_size <= wp->sectors_free &&
835 	    (op->crc.compression_type == bch2_compression_opt_to_type(op->compression_opt) ||
836 	     op->incompressible)) {
837 		if (!crc_is_compressed(op->crc) &&
838 		    op->csum_type != op->crc.csum_type &&
839 		    bch2_write_rechecksum(c, op, op->csum_type) &&
840 		    !c->opts.no_data_io)
841 			return PREP_ENCODED_CHECKSUM_ERR;
842 
843 		return PREP_ENCODED_DO_WRITE;
844 	}
845 
846 	/*
847 	 * If the data is compressed and we couldn't write the entire extent as
848 	 * is, we have to decompress it:
849 	 */
850 	if (crc_is_compressed(op->crc)) {
851 		struct bch_csum csum;
852 
853 		if (bch2_write_decrypt(op))
854 			return PREP_ENCODED_CHECKSUM_ERR;
855 
856 		/* Last point we can still verify checksum: */
857 		csum = bch2_checksum_bio(c, op->crc.csum_type,
858 					 extent_nonce(op->version, op->crc),
859 					 bio);
860 		if (bch2_crc_cmp(op->crc.csum, csum) && !c->opts.no_data_io)
861 			return PREP_ENCODED_CHECKSUM_ERR;
862 
863 		if (bch2_bio_uncompress_inplace(c, bio, &op->crc))
864 			return PREP_ENCODED_ERR;
865 	}
866 
867 	/*
868 	 * No longer have compressed data after this point - data might be
869 	 * encrypted:
870 	 */
871 
872 	/*
873 	 * If the data is checksummed and we're only writing a subset,
874 	 * rechecksum and adjust bio to point to currently live data:
875 	 */
876 	if ((op->crc.live_size != op->crc.uncompressed_size ||
877 	     op->crc.csum_type != op->csum_type) &&
878 	    bch2_write_rechecksum(c, op, op->csum_type) &&
879 	    !c->opts.no_data_io)
880 		return PREP_ENCODED_CHECKSUM_ERR;
881 
882 	/*
883 	 * If we want to compress the data, it has to be decrypted:
884 	 */
885 	if ((op->compression_opt ||
886 	     bch2_csum_type_is_encryption(op->crc.csum_type) !=
887 	     bch2_csum_type_is_encryption(op->csum_type)) &&
888 	    bch2_write_decrypt(op))
889 		return PREP_ENCODED_CHECKSUM_ERR;
890 
891 	return PREP_ENCODED_OK;
892 }
893 
894 static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp,
895 			     struct bio **_dst)
896 {
897 	struct bch_fs *c = op->c;
898 	struct bio *src = &op->wbio.bio, *dst = src;
899 	struct bvec_iter saved_iter;
900 	void *ec_buf;
901 	unsigned total_output = 0, total_input = 0;
902 	bool bounce = false;
903 	bool page_alloc_failed = false;
904 	int ret, more = 0;
905 
906 	BUG_ON(!bio_sectors(src));
907 
908 	ec_buf = bch2_writepoint_ec_buf(c, wp);
909 
910 	switch (bch2_write_prep_encoded_data(op, wp)) {
911 	case PREP_ENCODED_OK:
912 		break;
913 	case PREP_ENCODED_ERR:
914 		ret = -EIO;
915 		goto err;
916 	case PREP_ENCODED_CHECKSUM_ERR:
917 		goto csum_err;
918 	case PREP_ENCODED_DO_WRITE:
919 		/* XXX look for bug here */
920 		if (ec_buf) {
921 			dst = bch2_write_bio_alloc(c, wp, src,
922 						   &page_alloc_failed,
923 						   ec_buf);
924 			bio_copy_data(dst, src);
925 			bounce = true;
926 		}
927 		init_append_extent(op, wp, op->version, op->crc);
928 		goto do_write;
929 	}
930 
931 	if (ec_buf ||
932 	    op->compression_opt ||
933 	    (op->csum_type &&
934 	     !(op->flags & BCH_WRITE_PAGES_STABLE)) ||
935 	    (bch2_csum_type_is_encryption(op->csum_type) &&
936 	     !(op->flags & BCH_WRITE_PAGES_OWNED))) {
937 		dst = bch2_write_bio_alloc(c, wp, src,
938 					   &page_alloc_failed,
939 					   ec_buf);
940 		bounce = true;
941 	}
942 
943 	saved_iter = dst->bi_iter;
944 
945 	do {
946 		struct bch_extent_crc_unpacked crc = { 0 };
947 		struct bversion version = op->version;
948 		size_t dst_len = 0, src_len = 0;
949 
950 		if (page_alloc_failed &&
951 		    dst->bi_iter.bi_size  < (wp->sectors_free << 9) &&
952 		    dst->bi_iter.bi_size < c->opts.encoded_extent_max)
953 			break;
954 
955 		BUG_ON(op->compression_opt &&
956 		       (op->flags & BCH_WRITE_DATA_ENCODED) &&
957 		       bch2_csum_type_is_encryption(op->crc.csum_type));
958 		BUG_ON(op->compression_opt && !bounce);
959 
960 		crc.compression_type = op->incompressible
961 			? BCH_COMPRESSION_TYPE_incompressible
962 			: op->compression_opt
963 			? bch2_bio_compress(c, dst, &dst_len, src, &src_len,
964 					    op->compression_opt)
965 			: 0;
966 		if (!crc_is_compressed(crc)) {
967 			dst_len = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
968 			dst_len = min_t(unsigned, dst_len, wp->sectors_free << 9);
969 
970 			if (op->csum_type)
971 				dst_len = min_t(unsigned, dst_len,
972 						c->opts.encoded_extent_max);
973 
974 			if (bounce) {
975 				swap(dst->bi_iter.bi_size, dst_len);
976 				bio_copy_data(dst, src);
977 				swap(dst->bi_iter.bi_size, dst_len);
978 			}
979 
980 			src_len = dst_len;
981 		}
982 
983 		BUG_ON(!src_len || !dst_len);
984 
985 		if (bch2_csum_type_is_encryption(op->csum_type)) {
986 			if (bversion_zero(version)) {
987 				version.lo = atomic64_inc_return(&c->key_version);
988 			} else {
989 				crc.nonce = op->nonce;
990 				op->nonce += src_len >> 9;
991 			}
992 		}
993 
994 		if ((op->flags & BCH_WRITE_DATA_ENCODED) &&
995 		    !crc_is_compressed(crc) &&
996 		    bch2_csum_type_is_encryption(op->crc.csum_type) ==
997 		    bch2_csum_type_is_encryption(op->csum_type)) {
998 			u8 compression_type = crc.compression_type;
999 			u16 nonce = crc.nonce;
1000 			/*
1001 			 * Note: when we're using rechecksum(), we need to be
1002 			 * checksumming @src because it has all the data our
1003 			 * existing checksum covers - if we bounced (because we
1004 			 * were trying to compress), @dst will only have the
1005 			 * part of the data the new checksum will cover.
1006 			 *
1007 			 * But normally we want to be checksumming post bounce,
1008 			 * because part of the reason for bouncing is so the
1009 			 * data can't be modified (by userspace) while it's in
1010 			 * flight.
1011 			 */
1012 			if (bch2_rechecksum_bio(c, src, version, op->crc,
1013 					&crc, &op->crc,
1014 					src_len >> 9,
1015 					bio_sectors(src) - (src_len >> 9),
1016 					op->csum_type))
1017 				goto csum_err;
1018 			/*
1019 			 * rchecksum_bio sets compression_type on crc from op->crc,
1020 			 * this isn't always correct as sometimes we're changing
1021 			 * an extent from uncompressed to incompressible.
1022 			 */
1023 			crc.compression_type = compression_type;
1024 			crc.nonce = nonce;
1025 		} else {
1026 			if ((op->flags & BCH_WRITE_DATA_ENCODED) &&
1027 			    bch2_rechecksum_bio(c, src, version, op->crc,
1028 					NULL, &op->crc,
1029 					src_len >> 9,
1030 					bio_sectors(src) - (src_len >> 9),
1031 					op->crc.csum_type))
1032 				goto csum_err;
1033 
1034 			crc.compressed_size	= dst_len >> 9;
1035 			crc.uncompressed_size	= src_len >> 9;
1036 			crc.live_size		= src_len >> 9;
1037 
1038 			swap(dst->bi_iter.bi_size, dst_len);
1039 			ret = bch2_encrypt_bio(c, op->csum_type,
1040 					       extent_nonce(version, crc), dst);
1041 			if (ret)
1042 				goto err;
1043 
1044 			crc.csum = bch2_checksum_bio(c, op->csum_type,
1045 					 extent_nonce(version, crc), dst);
1046 			crc.csum_type = op->csum_type;
1047 			swap(dst->bi_iter.bi_size, dst_len);
1048 		}
1049 
1050 		init_append_extent(op, wp, version, crc);
1051 
1052 		if (dst != src)
1053 			bio_advance(dst, dst_len);
1054 		bio_advance(src, src_len);
1055 		total_output	+= dst_len;
1056 		total_input	+= src_len;
1057 	} while (dst->bi_iter.bi_size &&
1058 		 src->bi_iter.bi_size &&
1059 		 wp->sectors_free &&
1060 		 !bch2_keylist_realloc(&op->insert_keys,
1061 				      op->inline_keys,
1062 				      ARRAY_SIZE(op->inline_keys),
1063 				      BKEY_EXTENT_U64s_MAX));
1064 
1065 	more = src->bi_iter.bi_size != 0;
1066 
1067 	dst->bi_iter = saved_iter;
1068 
1069 	if (dst == src && more) {
1070 		BUG_ON(total_output != total_input);
1071 
1072 		dst = bio_split(src, total_input >> 9,
1073 				GFP_NOFS, &c->bio_write);
1074 		wbio_init(dst)->put_bio	= true;
1075 		/* copy WRITE_SYNC flag */
1076 		dst->bi_opf		= src->bi_opf;
1077 	}
1078 
1079 	dst->bi_iter.bi_size = total_output;
1080 do_write:
1081 	*_dst = dst;
1082 	return more;
1083 csum_err:
1084 	bch_err(c, "%s writ error: error verifying existing checksum while rewriting existing data (memory corruption?)",
1085 		op->flags & BCH_WRITE_MOVE ? "move" : "user");
1086 	ret = -EIO;
1087 err:
1088 	if (to_wbio(dst)->bounce)
1089 		bch2_bio_free_pages_pool(c, dst);
1090 	if (to_wbio(dst)->put_bio)
1091 		bio_put(dst);
1092 
1093 	return ret;
1094 }
1095 
1096 static bool bch2_extent_is_writeable(struct bch_write_op *op,
1097 				     struct bkey_s_c k)
1098 {
1099 	struct bch_fs *c = op->c;
1100 	struct bkey_s_c_extent e;
1101 	struct extent_ptr_decoded p;
1102 	const union bch_extent_entry *entry;
1103 	unsigned replicas = 0;
1104 
1105 	if (k.k->type != KEY_TYPE_extent)
1106 		return false;
1107 
1108 	e = bkey_s_c_to_extent(k);
1109 
1110 	rcu_read_lock();
1111 	extent_for_each_ptr_decode(e, p, entry) {
1112 		if (crc_is_encoded(p.crc) || p.has_ec) {
1113 			rcu_read_unlock();
1114 			return false;
1115 		}
1116 
1117 		replicas += bch2_extent_ptr_durability(c, &p);
1118 	}
1119 	rcu_read_unlock();
1120 
1121 	return replicas >= op->opts.data_replicas;
1122 }
1123 
1124 static int bch2_nocow_write_convert_one_unwritten(struct btree_trans *trans,
1125 						  struct btree_iter *iter,
1126 						  struct bkey_i *orig,
1127 						  struct bkey_s_c k,
1128 						  u64 new_i_size)
1129 {
1130 	if (!bch2_extents_match(bkey_i_to_s_c(orig), k)) {
1131 		/* trace this */
1132 		return 0;
1133 	}
1134 
1135 	struct bkey_i *new = bch2_bkey_make_mut_noupdate(trans, k);
1136 	int ret = PTR_ERR_OR_ZERO(new);
1137 	if (ret)
1138 		return ret;
1139 
1140 	bch2_cut_front(bkey_start_pos(&orig->k), new);
1141 	bch2_cut_back(orig->k.p, new);
1142 
1143 	struct bkey_ptrs ptrs = bch2_bkey_ptrs(bkey_i_to_s(new));
1144 	bkey_for_each_ptr(ptrs, ptr)
1145 		ptr->unwritten = 0;
1146 
1147 	/*
1148 	 * Note that we're not calling bch2_subvol_get_snapshot() in this path -
1149 	 * that was done when we kicked off the write, and here it's important
1150 	 * that we update the extent that we wrote to - even if a snapshot has
1151 	 * since been created. The write is still outstanding, so we're ok
1152 	 * w.r.t. snapshot atomicity:
1153 	 */
1154 	return  bch2_extent_update_i_size_sectors(trans, iter,
1155 					min(new->k.p.offset << 9, new_i_size), 0) ?:
1156 		bch2_trans_update(trans, iter, new,
1157 				  BTREE_UPDATE_internal_snapshot_node);
1158 }
1159 
1160 static void bch2_nocow_write_convert_unwritten(struct bch_write_op *op)
1161 {
1162 	struct bch_fs *c = op->c;
1163 	struct btree_trans *trans = bch2_trans_get(c);
1164 
1165 	for_each_keylist_key(&op->insert_keys, orig) {
1166 		int ret = for_each_btree_key_upto_commit(trans, iter, BTREE_ID_extents,
1167 				     bkey_start_pos(&orig->k), orig->k.p,
1168 				     BTREE_ITER_intent, k,
1169 				     NULL, NULL, BCH_TRANS_COMMIT_no_enospc, ({
1170 			bch2_nocow_write_convert_one_unwritten(trans, &iter, orig, k, op->new_i_size);
1171 		}));
1172 
1173 		if (ret && !bch2_err_matches(ret, EROFS)) {
1174 			struct bkey_i *insert = bch2_keylist_front(&op->insert_keys);
1175 
1176 			bch_err_inum_offset_ratelimited(c,
1177 				insert->k.p.inode, insert->k.p.offset << 9,
1178 				"%s write error while doing btree update: %s",
1179 				op->flags & BCH_WRITE_MOVE ? "move" : "user",
1180 				bch2_err_str(ret));
1181 		}
1182 
1183 		if (ret) {
1184 			op->error = ret;
1185 			break;
1186 		}
1187 	}
1188 
1189 	bch2_trans_put(trans);
1190 }
1191 
1192 static void __bch2_nocow_write_done(struct bch_write_op *op)
1193 {
1194 	if (unlikely(op->flags & BCH_WRITE_IO_ERROR)) {
1195 		op->error = -EIO;
1196 	} else if (unlikely(op->flags & BCH_WRITE_CONVERT_UNWRITTEN))
1197 		bch2_nocow_write_convert_unwritten(op);
1198 }
1199 
1200 static CLOSURE_CALLBACK(bch2_nocow_write_done)
1201 {
1202 	closure_type(op, struct bch_write_op, cl);
1203 
1204 	__bch2_nocow_write_done(op);
1205 	bch2_write_done(cl);
1206 }
1207 
1208 struct bucket_to_lock {
1209 	struct bpos		b;
1210 	unsigned		gen;
1211 	struct nocow_lock_bucket *l;
1212 };
1213 
1214 static void bch2_nocow_write(struct bch_write_op *op)
1215 {
1216 	struct bch_fs *c = op->c;
1217 	struct btree_trans *trans;
1218 	struct btree_iter iter;
1219 	struct bkey_s_c k;
1220 	DARRAY_PREALLOCATED(struct bucket_to_lock, 3) buckets;
1221 	u32 snapshot;
1222 	struct bucket_to_lock *stale_at;
1223 	int ret;
1224 
1225 	if (op->flags & BCH_WRITE_MOVE)
1226 		return;
1227 
1228 	darray_init(&buckets);
1229 	trans = bch2_trans_get(c);
1230 retry:
1231 	bch2_trans_begin(trans);
1232 
1233 	ret = bch2_subvolume_get_snapshot(trans, op->subvol, &snapshot);
1234 	if (unlikely(ret))
1235 		goto err;
1236 
1237 	bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
1238 			     SPOS(op->pos.inode, op->pos.offset, snapshot),
1239 			     BTREE_ITER_slots);
1240 	while (1) {
1241 		struct bio *bio = &op->wbio.bio;
1242 
1243 		buckets.nr = 0;
1244 
1245 		ret = bch2_trans_relock(trans);
1246 		if (ret)
1247 			break;
1248 
1249 		k = bch2_btree_iter_peek_slot(&iter);
1250 		ret = bkey_err(k);
1251 		if (ret)
1252 			break;
1253 
1254 		/* fall back to normal cow write path? */
1255 		if (unlikely(k.k->p.snapshot != snapshot ||
1256 			     !bch2_extent_is_writeable(op, k)))
1257 			break;
1258 
1259 		if (bch2_keylist_realloc(&op->insert_keys,
1260 					 op->inline_keys,
1261 					 ARRAY_SIZE(op->inline_keys),
1262 					 k.k->u64s))
1263 			break;
1264 
1265 		/* Get iorefs before dropping btree locks: */
1266 		struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
1267 		bkey_for_each_ptr(ptrs, ptr) {
1268 			struct bch_dev *ca = bch2_dev_get_ioref(c, ptr->dev, WRITE);
1269 			if (unlikely(!ca))
1270 				goto err_get_ioref;
1271 
1272 			struct bpos b = PTR_BUCKET_POS(ca, ptr);
1273 			struct nocow_lock_bucket *l =
1274 				bucket_nocow_lock(&c->nocow_locks, bucket_to_u64(b));
1275 			prefetch(l);
1276 
1277 			/* XXX allocating memory with btree locks held - rare */
1278 			darray_push_gfp(&buckets, ((struct bucket_to_lock) {
1279 						   .b = b, .gen = ptr->gen, .l = l,
1280 						   }), GFP_KERNEL|__GFP_NOFAIL);
1281 
1282 			if (ptr->unwritten)
1283 				op->flags |= BCH_WRITE_CONVERT_UNWRITTEN;
1284 		}
1285 
1286 		/* Unlock before taking nocow locks, doing IO: */
1287 		bkey_reassemble(op->insert_keys.top, k);
1288 		bch2_trans_unlock(trans);
1289 
1290 		bch2_cut_front(op->pos, op->insert_keys.top);
1291 		if (op->flags & BCH_WRITE_CONVERT_UNWRITTEN)
1292 			bch2_cut_back(POS(op->pos.inode, op->pos.offset + bio_sectors(bio)), op->insert_keys.top);
1293 
1294 		darray_for_each(buckets, i) {
1295 			struct bch_dev *ca = bch2_dev_have_ref(c, i->b.inode);
1296 
1297 			__bch2_bucket_nocow_lock(&c->nocow_locks, i->l,
1298 						 bucket_to_u64(i->b),
1299 						 BUCKET_NOCOW_LOCK_UPDATE);
1300 
1301 			rcu_read_lock();
1302 			bool stale = gen_after(*bucket_gen(ca, i->b.offset), i->gen);
1303 			rcu_read_unlock();
1304 
1305 			if (unlikely(stale)) {
1306 				stale_at = i;
1307 				goto err_bucket_stale;
1308 			}
1309 		}
1310 
1311 		bio = &op->wbio.bio;
1312 		if (k.k->p.offset < op->pos.offset + bio_sectors(bio)) {
1313 			bio = bio_split(bio, k.k->p.offset - op->pos.offset,
1314 					GFP_KERNEL, &c->bio_write);
1315 			wbio_init(bio)->put_bio = true;
1316 			bio->bi_opf = op->wbio.bio.bi_opf;
1317 		} else {
1318 			op->flags |= BCH_WRITE_DONE;
1319 		}
1320 
1321 		op->pos.offset += bio_sectors(bio);
1322 		op->written += bio_sectors(bio);
1323 
1324 		bio->bi_end_io	= bch2_write_endio;
1325 		bio->bi_private	= &op->cl;
1326 		bio->bi_opf |= REQ_OP_WRITE;
1327 		closure_get(&op->cl);
1328 		bch2_submit_wbio_replicas(to_wbio(bio), c, BCH_DATA_user,
1329 					  op->insert_keys.top, true);
1330 
1331 		bch2_keylist_push(&op->insert_keys);
1332 		if (op->flags & BCH_WRITE_DONE)
1333 			break;
1334 		bch2_btree_iter_advance(&iter);
1335 	}
1336 out:
1337 	bch2_trans_iter_exit(trans, &iter);
1338 err:
1339 	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
1340 		goto retry;
1341 
1342 	if (ret) {
1343 		bch_err_inum_offset_ratelimited(c,
1344 			op->pos.inode, op->pos.offset << 9,
1345 			"%s: btree lookup error %s", __func__, bch2_err_str(ret));
1346 		op->error = ret;
1347 		op->flags |= BCH_WRITE_DONE;
1348 	}
1349 
1350 	bch2_trans_put(trans);
1351 	darray_exit(&buckets);
1352 
1353 	/* fallback to cow write path? */
1354 	if (!(op->flags & BCH_WRITE_DONE)) {
1355 		closure_sync(&op->cl);
1356 		__bch2_nocow_write_done(op);
1357 		op->insert_keys.top = op->insert_keys.keys;
1358 	} else if (op->flags & BCH_WRITE_SYNC) {
1359 		closure_sync(&op->cl);
1360 		bch2_nocow_write_done(&op->cl.work);
1361 	} else {
1362 		/*
1363 		 * XXX
1364 		 * needs to run out of process context because ei_quota_lock is
1365 		 * a mutex
1366 		 */
1367 		continue_at(&op->cl, bch2_nocow_write_done, index_update_wq(op));
1368 	}
1369 	return;
1370 err_get_ioref:
1371 	darray_for_each(buckets, i)
1372 		percpu_ref_put(&bch2_dev_have_ref(c, i->b.inode)->io_ref);
1373 
1374 	/* Fall back to COW path: */
1375 	goto out;
1376 err_bucket_stale:
1377 	darray_for_each(buckets, i) {
1378 		bch2_bucket_nocow_unlock(&c->nocow_locks, i->b, BUCKET_NOCOW_LOCK_UPDATE);
1379 		if (i == stale_at)
1380 			break;
1381 	}
1382 
1383 	/* We can retry this: */
1384 	ret = -BCH_ERR_transaction_restart;
1385 	goto err_get_ioref;
1386 }
1387 
1388 static void __bch2_write(struct bch_write_op *op)
1389 {
1390 	struct bch_fs *c = op->c;
1391 	struct write_point *wp = NULL;
1392 	struct bio *bio = NULL;
1393 	unsigned nofs_flags;
1394 	int ret;
1395 
1396 	nofs_flags = memalloc_nofs_save();
1397 
1398 	if (unlikely(op->opts.nocow && c->opts.nocow_enabled)) {
1399 		bch2_nocow_write(op);
1400 		if (op->flags & BCH_WRITE_DONE)
1401 			goto out_nofs_restore;
1402 	}
1403 again:
1404 	memset(&op->failed, 0, sizeof(op->failed));
1405 
1406 	do {
1407 		struct bkey_i *key_to_write;
1408 		unsigned key_to_write_offset = op->insert_keys.top_p -
1409 			op->insert_keys.keys_p;
1410 
1411 		/* +1 for possible cache device: */
1412 		if (op->open_buckets.nr + op->nr_replicas + 1 >
1413 		    ARRAY_SIZE(op->open_buckets.v))
1414 			break;
1415 
1416 		if (bch2_keylist_realloc(&op->insert_keys,
1417 					op->inline_keys,
1418 					ARRAY_SIZE(op->inline_keys),
1419 					BKEY_EXTENT_U64s_MAX))
1420 			break;
1421 
1422 		/*
1423 		 * The copygc thread is now global, which means it's no longer
1424 		 * freeing up space on specific disks, which means that
1425 		 * allocations for specific disks may hang arbitrarily long:
1426 		 */
1427 		ret = bch2_trans_do(c, NULL, NULL, 0,
1428 			bch2_alloc_sectors_start_trans(trans,
1429 				op->target,
1430 				op->opts.erasure_code && !(op->flags & BCH_WRITE_CACHED),
1431 				op->write_point,
1432 				&op->devs_have,
1433 				op->nr_replicas,
1434 				op->nr_replicas_required,
1435 				op->watermark,
1436 				op->flags,
1437 				(op->flags & (BCH_WRITE_ALLOC_NOWAIT|
1438 					      BCH_WRITE_ONLY_SPECIFIED_DEVS))
1439 				? NULL : &op->cl, &wp));
1440 		if (unlikely(ret)) {
1441 			if (bch2_err_matches(ret, BCH_ERR_operation_blocked))
1442 				break;
1443 
1444 			goto err;
1445 		}
1446 
1447 		EBUG_ON(!wp);
1448 
1449 		bch2_open_bucket_get(c, wp, &op->open_buckets);
1450 		ret = bch2_write_extent(op, wp, &bio);
1451 
1452 		bch2_alloc_sectors_done_inlined(c, wp);
1453 err:
1454 		if (ret <= 0) {
1455 			op->flags |= BCH_WRITE_DONE;
1456 
1457 			if (ret < 0) {
1458 				if (!(op->flags & BCH_WRITE_ALLOC_NOWAIT))
1459 					bch_err_inum_offset_ratelimited(c,
1460 						op->pos.inode,
1461 						op->pos.offset << 9,
1462 						"%s(): %s error: %s", __func__,
1463 						op->flags & BCH_WRITE_MOVE ? "move" : "user",
1464 						bch2_err_str(ret));
1465 				op->error = ret;
1466 				break;
1467 			}
1468 		}
1469 
1470 		bio->bi_end_io	= bch2_write_endio;
1471 		bio->bi_private	= &op->cl;
1472 		bio->bi_opf |= REQ_OP_WRITE;
1473 
1474 		closure_get(bio->bi_private);
1475 
1476 		key_to_write = (void *) (op->insert_keys.keys_p +
1477 					 key_to_write_offset);
1478 
1479 		bch2_submit_wbio_replicas(to_wbio(bio), c, BCH_DATA_user,
1480 					  key_to_write, false);
1481 	} while (ret);
1482 
1483 	/*
1484 	 * Sync or no?
1485 	 *
1486 	 * If we're running asynchronously, wne may still want to block
1487 	 * synchronously here if we weren't able to submit all of the IO at
1488 	 * once, as that signals backpressure to the caller.
1489 	 */
1490 	if ((op->flags & BCH_WRITE_SYNC) ||
1491 	    (!(op->flags & BCH_WRITE_DONE) &&
1492 	     !(op->flags & BCH_WRITE_IN_WORKER))) {
1493 		if (closure_sync_timeout(&op->cl, HZ * 10)) {
1494 			bch2_print_allocator_stuck(c);
1495 			closure_sync(&op->cl);
1496 		}
1497 
1498 		__bch2_write_index(op);
1499 
1500 		if (!(op->flags & BCH_WRITE_DONE))
1501 			goto again;
1502 		bch2_write_done(&op->cl);
1503 	} else {
1504 		bch2_write_queue(op, wp);
1505 		continue_at(&op->cl, bch2_write_index, NULL);
1506 	}
1507 out_nofs_restore:
1508 	memalloc_nofs_restore(nofs_flags);
1509 }
1510 
1511 static void bch2_write_data_inline(struct bch_write_op *op, unsigned data_len)
1512 {
1513 	struct bio *bio = &op->wbio.bio;
1514 	struct bvec_iter iter;
1515 	struct bkey_i_inline_data *id;
1516 	unsigned sectors;
1517 	int ret;
1518 
1519 	memset(&op->failed, 0, sizeof(op->failed));
1520 
1521 	op->flags |= BCH_WRITE_WROTE_DATA_INLINE;
1522 	op->flags |= BCH_WRITE_DONE;
1523 
1524 	bch2_check_set_feature(op->c, BCH_FEATURE_inline_data);
1525 
1526 	ret = bch2_keylist_realloc(&op->insert_keys, op->inline_keys,
1527 				   ARRAY_SIZE(op->inline_keys),
1528 				   BKEY_U64s + DIV_ROUND_UP(data_len, 8));
1529 	if (ret) {
1530 		op->error = ret;
1531 		goto err;
1532 	}
1533 
1534 	sectors = bio_sectors(bio);
1535 	op->pos.offset += sectors;
1536 
1537 	id = bkey_inline_data_init(op->insert_keys.top);
1538 	id->k.p		= op->pos;
1539 	id->k.version	= op->version;
1540 	id->k.size	= sectors;
1541 
1542 	iter = bio->bi_iter;
1543 	iter.bi_size = data_len;
1544 	memcpy_from_bio(id->v.data, bio, iter);
1545 
1546 	while (data_len & 7)
1547 		id->v.data[data_len++] = '\0';
1548 	set_bkey_val_bytes(&id->k, data_len);
1549 	bch2_keylist_push(&op->insert_keys);
1550 
1551 	__bch2_write_index(op);
1552 err:
1553 	bch2_write_done(&op->cl);
1554 }
1555 
1556 /**
1557  * bch2_write() - handle a write to a cache device or flash only volume
1558  * @cl:		&bch_write_op->cl
1559  *
1560  * This is the starting point for any data to end up in a cache device; it could
1561  * be from a normal write, or a writeback write, or a write to a flash only
1562  * volume - it's also used by the moving garbage collector to compact data in
1563  * mostly empty buckets.
1564  *
1565  * It first writes the data to the cache, creating a list of keys to be inserted
1566  * (if the data won't fit in a single open bucket, there will be multiple keys);
1567  * after the data is written it calls bch_journal, and after the keys have been
1568  * added to the next journal write they're inserted into the btree.
1569  *
1570  * If op->discard is true, instead of inserting the data it invalidates the
1571  * region of the cache represented by op->bio and op->inode.
1572  */
1573 CLOSURE_CALLBACK(bch2_write)
1574 {
1575 	closure_type(op, struct bch_write_op, cl);
1576 	struct bio *bio = &op->wbio.bio;
1577 	struct bch_fs *c = op->c;
1578 	unsigned data_len;
1579 
1580 	EBUG_ON(op->cl.parent);
1581 	BUG_ON(!op->nr_replicas);
1582 	BUG_ON(!op->write_point.v);
1583 	BUG_ON(bkey_eq(op->pos, POS_MAX));
1584 
1585 	op->nr_replicas_required = min_t(unsigned, op->nr_replicas_required, op->nr_replicas);
1586 	op->start_time = local_clock();
1587 	bch2_keylist_init(&op->insert_keys, op->inline_keys);
1588 	wbio_init(bio)->put_bio = false;
1589 
1590 	if (bio->bi_iter.bi_size & (c->opts.block_size - 1)) {
1591 		bch_err_inum_offset_ratelimited(c,
1592 			op->pos.inode,
1593 			op->pos.offset << 9,
1594 			"%s write error: misaligned write",
1595 			op->flags & BCH_WRITE_MOVE ? "move" : "user");
1596 		op->error = -EIO;
1597 		goto err;
1598 	}
1599 
1600 	if (c->opts.nochanges) {
1601 		op->error = -BCH_ERR_erofs_no_writes;
1602 		goto err;
1603 	}
1604 
1605 	if (!(op->flags & BCH_WRITE_MOVE) &&
1606 	    !bch2_write_ref_tryget(c, BCH_WRITE_REF_write)) {
1607 		op->error = -BCH_ERR_erofs_no_writes;
1608 		goto err;
1609 	}
1610 
1611 	this_cpu_add(c->counters[BCH_COUNTER_io_write], bio_sectors(bio));
1612 	bch2_increment_clock(c, bio_sectors(bio), WRITE);
1613 
1614 	data_len = min_t(u64, bio->bi_iter.bi_size,
1615 			 op->new_i_size - (op->pos.offset << 9));
1616 
1617 	if (c->opts.inline_data &&
1618 	    data_len <= min(block_bytes(c) / 2, 1024U)) {
1619 		bch2_write_data_inline(op, data_len);
1620 		return;
1621 	}
1622 
1623 	__bch2_write(op);
1624 	return;
1625 err:
1626 	bch2_disk_reservation_put(c, &op->res);
1627 
1628 	closure_debug_destroy(&op->cl);
1629 	if (op->end_io)
1630 		op->end_io(op);
1631 }
1632 
1633 static const char * const bch2_write_flags[] = {
1634 #define x(f)	#f,
1635 	BCH_WRITE_FLAGS()
1636 #undef x
1637 	NULL
1638 };
1639 
1640 void bch2_write_op_to_text(struct printbuf *out, struct bch_write_op *op)
1641 {
1642 	prt_str(out, "pos: ");
1643 	bch2_bpos_to_text(out, op->pos);
1644 	prt_newline(out);
1645 	printbuf_indent_add(out, 2);
1646 
1647 	prt_str(out, "started: ");
1648 	bch2_pr_time_units(out, local_clock() - op->start_time);
1649 	prt_newline(out);
1650 
1651 	prt_str(out, "flags: ");
1652 	prt_bitflags(out, bch2_write_flags, op->flags);
1653 	prt_newline(out);
1654 
1655 	prt_printf(out, "ref: %u\n", closure_nr_remaining(&op->cl));
1656 
1657 	printbuf_indent_sub(out, 2);
1658 }
1659 
1660 void bch2_fs_io_write_exit(struct bch_fs *c)
1661 {
1662 	mempool_exit(&c->bio_bounce_pages);
1663 	bioset_exit(&c->replica_set);
1664 	bioset_exit(&c->bio_write);
1665 }
1666 
1667 int bch2_fs_io_write_init(struct bch_fs *c)
1668 {
1669 	if (bioset_init(&c->bio_write,   1, offsetof(struct bch_write_bio, bio), BIOSET_NEED_BVECS) ||
1670 	    bioset_init(&c->replica_set, 4, offsetof(struct bch_write_bio, bio), 0))
1671 		return -BCH_ERR_ENOMEM_bio_write_init;
1672 
1673 	if (mempool_init_page_pool(&c->bio_bounce_pages,
1674 				   max_t(unsigned,
1675 					 c->opts.btree_node_size,
1676 					 c->opts.encoded_extent_max) /
1677 				   PAGE_SIZE, 0))
1678 		return -BCH_ERR_ENOMEM_bio_bounce_pages_init;
1679 
1680 	return 0;
1681 }
1682