xref: /linux/fs/bcachefs/ec.c (revision 7255fcc80d4b525cc10cfaaf7f485830d4ed2000)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 /* erasure coding */
4 
5 #include "bcachefs.h"
6 #include "alloc_background.h"
7 #include "alloc_foreground.h"
8 #include "backpointers.h"
9 #include "bkey_buf.h"
10 #include "bset.h"
11 #include "btree_gc.h"
12 #include "btree_update.h"
13 #include "btree_write_buffer.h"
14 #include "buckets.h"
15 #include "checksum.h"
16 #include "disk_groups.h"
17 #include "ec.h"
18 #include "error.h"
19 #include "io_read.h"
20 #include "keylist.h"
21 #include "recovery.h"
22 #include "replicas.h"
23 #include "super-io.h"
24 #include "util.h"
25 
26 #include <linux/sort.h>
27 
28 #ifdef __KERNEL__
29 
30 #include <linux/raid/pq.h>
31 #include <linux/raid/xor.h>
32 
33 static void raid5_recov(unsigned disks, unsigned failed_idx,
34 			size_t size, void **data)
35 {
36 	unsigned i = 2, nr;
37 
38 	BUG_ON(failed_idx >= disks);
39 
40 	swap(data[0], data[failed_idx]);
41 	memcpy(data[0], data[1], size);
42 
43 	while (i < disks) {
44 		nr = min_t(unsigned, disks - i, MAX_XOR_BLOCKS);
45 		xor_blocks(nr, size, data[0], data + i);
46 		i += nr;
47 	}
48 
49 	swap(data[0], data[failed_idx]);
50 }
51 
52 static void raid_gen(int nd, int np, size_t size, void **v)
53 {
54 	if (np >= 1)
55 		raid5_recov(nd + np, nd, size, v);
56 	if (np >= 2)
57 		raid6_call.gen_syndrome(nd + np, size, v);
58 	BUG_ON(np > 2);
59 }
60 
61 static void raid_rec(int nr, int *ir, int nd, int np, size_t size, void **v)
62 {
63 	switch (nr) {
64 	case 0:
65 		break;
66 	case 1:
67 		if (ir[0] < nd + 1)
68 			raid5_recov(nd + 1, ir[0], size, v);
69 		else
70 			raid6_call.gen_syndrome(nd + np, size, v);
71 		break;
72 	case 2:
73 		if (ir[1] < nd) {
74 			/* data+data failure. */
75 			raid6_2data_recov(nd + np, size, ir[0], ir[1], v);
76 		} else if (ir[0] < nd) {
77 			/* data + p/q failure */
78 
79 			if (ir[1] == nd) /* data + p failure */
80 				raid6_datap_recov(nd + np, size, ir[0], v);
81 			else { /* data + q failure */
82 				raid5_recov(nd + 1, ir[0], size, v);
83 				raid6_call.gen_syndrome(nd + np, size, v);
84 			}
85 		} else {
86 			raid_gen(nd, np, size, v);
87 		}
88 		break;
89 	default:
90 		BUG();
91 	}
92 }
93 
94 #else
95 
96 #include <raid/raid.h>
97 
98 #endif
99 
100 struct ec_bio {
101 	struct bch_dev		*ca;
102 	struct ec_stripe_buf	*buf;
103 	size_t			idx;
104 	struct bio		bio;
105 };
106 
107 /* Stripes btree keys: */
108 
109 int bch2_stripe_invalid(struct bch_fs *c, struct bkey_s_c k,
110 			enum bkey_invalid_flags flags,
111 			struct printbuf *err)
112 {
113 	const struct bch_stripe *s = bkey_s_c_to_stripe(k).v;
114 	int ret = 0;
115 
116 	bkey_fsck_err_on(bkey_eq(k.k->p, POS_MIN) ||
117 			 bpos_gt(k.k->p, POS(0, U32_MAX)), c, err,
118 			 stripe_pos_bad,
119 			 "stripe at bad pos");
120 
121 	bkey_fsck_err_on(bkey_val_u64s(k.k) < stripe_val_u64s(s), c, err,
122 			 stripe_val_size_bad,
123 			 "incorrect value size (%zu < %u)",
124 			 bkey_val_u64s(k.k), stripe_val_u64s(s));
125 
126 	ret = bch2_bkey_ptrs_invalid(c, k, flags, err);
127 fsck_err:
128 	return ret;
129 }
130 
131 void bch2_stripe_to_text(struct printbuf *out, struct bch_fs *c,
132 			 struct bkey_s_c k)
133 {
134 	const struct bch_stripe *sp = bkey_s_c_to_stripe(k).v;
135 	struct bch_stripe s = {};
136 
137 	memcpy(&s, sp, min(sizeof(s), bkey_val_bytes(k.k)));
138 
139 	unsigned nr_data = s.nr_blocks - s.nr_redundant;
140 
141 	prt_printf(out, "algo %u sectors %u blocks %u:%u csum ",
142 		   s.algorithm,
143 		   le16_to_cpu(s.sectors),
144 		   nr_data,
145 		   s.nr_redundant);
146 	bch2_prt_csum_type(out, s.csum_type);
147 	prt_printf(out, " gran %u", 1U << s.csum_granularity_bits);
148 
149 	for (unsigned i = 0; i < s.nr_blocks; i++) {
150 		const struct bch_extent_ptr *ptr = sp->ptrs + i;
151 
152 		if ((void *) ptr >= bkey_val_end(k))
153 			break;
154 
155 		bch2_extent_ptr_to_text(out, c, ptr);
156 
157 		if (s.csum_type < BCH_CSUM_NR &&
158 		    i < nr_data &&
159 		    stripe_blockcount_offset(&s, i) < bkey_val_bytes(k.k))
160 			prt_printf(out,  "#%u", stripe_blockcount_get(sp, i));
161 	}
162 }
163 
164 /* Triggers: */
165 
166 static int bch2_trans_mark_stripe_bucket(struct btree_trans *trans,
167 					 struct bkey_s_c_stripe s,
168 					 unsigned idx, bool deleting)
169 {
170 	struct bch_fs *c = trans->c;
171 	const struct bch_extent_ptr *ptr = &s.v->ptrs[idx];
172 	struct btree_iter iter;
173 	struct bkey_i_alloc_v4 *a;
174 	enum bch_data_type data_type = idx >= s.v->nr_blocks - s.v->nr_redundant
175 		? BCH_DATA_parity : 0;
176 	s64 sectors = data_type ? le16_to_cpu(s.v->sectors) : 0;
177 	int ret = 0;
178 
179 	if (deleting)
180 		sectors = -sectors;
181 
182 	a = bch2_trans_start_alloc_update(trans, &iter, PTR_BUCKET_POS(c, ptr));
183 	if (IS_ERR(a))
184 		return PTR_ERR(a);
185 
186 	ret = bch2_check_bucket_ref(trans, s.s_c, ptr, sectors, data_type,
187 				    a->v.gen, a->v.data_type,
188 				    a->v.dirty_sectors);
189 	if (ret)
190 		goto err;
191 
192 	if (!deleting) {
193 		if (bch2_trans_inconsistent_on(a->v.stripe ||
194 					       a->v.stripe_redundancy, trans,
195 				"bucket %llu:%llu gen %u data type %s dirty_sectors %u: multiple stripes using same bucket (%u, %llu)",
196 				iter.pos.inode, iter.pos.offset, a->v.gen,
197 				bch2_data_type_str(a->v.data_type),
198 				a->v.dirty_sectors,
199 				a->v.stripe, s.k->p.offset)) {
200 			ret = -EIO;
201 			goto err;
202 		}
203 
204 		if (bch2_trans_inconsistent_on(data_type && a->v.dirty_sectors, trans,
205 				"bucket %llu:%llu gen %u data type %s dirty_sectors %u: data already in stripe bucket %llu",
206 				iter.pos.inode, iter.pos.offset, a->v.gen,
207 				bch2_data_type_str(a->v.data_type),
208 				a->v.dirty_sectors,
209 				s.k->p.offset)) {
210 			ret = -EIO;
211 			goto err;
212 		}
213 
214 		a->v.stripe		= s.k->p.offset;
215 		a->v.stripe_redundancy	= s.v->nr_redundant;
216 		a->v.data_type		= BCH_DATA_stripe;
217 	} else {
218 		if (bch2_trans_inconsistent_on(a->v.stripe != s.k->p.offset ||
219 					       a->v.stripe_redundancy != s.v->nr_redundant, trans,
220 				"bucket %llu:%llu gen %u: not marked as stripe when deleting stripe %llu (got %u)",
221 				iter.pos.inode, iter.pos.offset, a->v.gen,
222 				s.k->p.offset, a->v.stripe)) {
223 			ret = -EIO;
224 			goto err;
225 		}
226 
227 		a->v.stripe		= 0;
228 		a->v.stripe_redundancy	= 0;
229 		a->v.data_type		= alloc_data_type(a->v, BCH_DATA_user);
230 	}
231 
232 	a->v.dirty_sectors += sectors;
233 	if (data_type)
234 		a->v.data_type = !deleting ? data_type : 0;
235 
236 	ret = bch2_trans_update(trans, &iter, &a->k_i, 0);
237 	if (ret)
238 		goto err;
239 err:
240 	bch2_trans_iter_exit(trans, &iter);
241 	return ret;
242 }
243 
244 static int mark_stripe_bucket(struct btree_trans *trans,
245 			      struct bkey_s_c k,
246 			      unsigned ptr_idx,
247 			      unsigned flags)
248 {
249 	struct bch_fs *c = trans->c;
250 	const struct bch_stripe *s = bkey_s_c_to_stripe(k).v;
251 	unsigned nr_data = s->nr_blocks - s->nr_redundant;
252 	bool parity = ptr_idx >= nr_data;
253 	enum bch_data_type data_type = parity ? BCH_DATA_parity : BCH_DATA_stripe;
254 	s64 sectors = parity ? le16_to_cpu(s->sectors) : 0;
255 	const struct bch_extent_ptr *ptr = s->ptrs + ptr_idx;
256 	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
257 	struct bucket old, new, *g;
258 	struct printbuf buf = PRINTBUF;
259 	int ret = 0;
260 
261 	BUG_ON(!(flags & BTREE_TRIGGER_GC));
262 
263 	/* * XXX doesn't handle deletion */
264 
265 	percpu_down_read(&c->mark_lock);
266 	g = PTR_GC_BUCKET(ca, ptr);
267 
268 	if (g->dirty_sectors ||
269 	    (g->stripe && g->stripe != k.k->p.offset)) {
270 		bch2_fs_inconsistent(c,
271 			      "bucket %u:%zu gen %u: multiple stripes using same bucket\n%s",
272 			      ptr->dev, PTR_BUCKET_NR(ca, ptr), g->gen,
273 			      (bch2_bkey_val_to_text(&buf, c, k), buf.buf));
274 		ret = -EINVAL;
275 		goto err;
276 	}
277 
278 	bucket_lock(g);
279 	old = *g;
280 
281 	ret = bch2_check_bucket_ref(trans, k, ptr, sectors, data_type,
282 				    g->gen, g->data_type,
283 				    g->dirty_sectors);
284 	if (ret)
285 		goto err;
286 
287 	g->data_type = data_type;
288 	g->dirty_sectors += sectors;
289 
290 	g->stripe		= k.k->p.offset;
291 	g->stripe_redundancy	= s->nr_redundant;
292 	new = *g;
293 err:
294 	bucket_unlock(g);
295 	if (!ret)
296 		bch2_dev_usage_update_m(c, ca, &old, &new);
297 	percpu_up_read(&c->mark_lock);
298 	printbuf_exit(&buf);
299 	return ret;
300 }
301 
302 int bch2_trigger_stripe(struct btree_trans *trans,
303 			enum btree_id btree_id, unsigned level,
304 			struct bkey_s_c old, struct bkey_s _new,
305 			unsigned flags)
306 {
307 	struct bkey_s_c new = _new.s_c;
308 	struct bch_fs *c = trans->c;
309 	u64 idx = new.k->p.offset;
310 	const struct bch_stripe *old_s = old.k->type == KEY_TYPE_stripe
311 		? bkey_s_c_to_stripe(old).v : NULL;
312 	const struct bch_stripe *new_s = new.k->type == KEY_TYPE_stripe
313 		? bkey_s_c_to_stripe(new).v : NULL;
314 
315 	if (flags & BTREE_TRIGGER_TRANSACTIONAL) {
316 		/*
317 		 * If the pointers aren't changing, we don't need to do anything:
318 		 */
319 		if (new_s && old_s &&
320 		    new_s->nr_blocks	== old_s->nr_blocks &&
321 		    new_s->nr_redundant	== old_s->nr_redundant &&
322 		    !memcmp(old_s->ptrs, new_s->ptrs,
323 			    new_s->nr_blocks * sizeof(struct bch_extent_ptr)))
324 			return 0;
325 
326 		BUG_ON(new_s && old_s &&
327 		       (new_s->nr_blocks	!= old_s->nr_blocks ||
328 			new_s->nr_redundant	!= old_s->nr_redundant));
329 
330 		if (new_s) {
331 			s64 sectors = le16_to_cpu(new_s->sectors);
332 
333 			struct bch_replicas_padded r;
334 			bch2_bkey_to_replicas(&r.e, new);
335 			int ret = bch2_update_replicas_list(trans, &r.e, sectors * new_s->nr_redundant);
336 			if (ret)
337 				return ret;
338 		}
339 
340 		if (old_s) {
341 			s64 sectors = -((s64) le16_to_cpu(old_s->sectors));
342 
343 			struct bch_replicas_padded r;
344 			bch2_bkey_to_replicas(&r.e, old);
345 			int ret = bch2_update_replicas_list(trans, &r.e, sectors * old_s->nr_redundant);
346 			if (ret)
347 				return ret;
348 		}
349 
350 		unsigned nr_blocks = new_s ? new_s->nr_blocks : old_s->nr_blocks;
351 		for (unsigned i = 0; i < nr_blocks; i++) {
352 			if (new_s && old_s &&
353 			    !memcmp(&new_s->ptrs[i],
354 				    &old_s->ptrs[i],
355 				    sizeof(new_s->ptrs[i])))
356 				continue;
357 
358 			if (new_s) {
359 				int ret = bch2_trans_mark_stripe_bucket(trans,
360 						bkey_s_c_to_stripe(new), i, false);
361 				if (ret)
362 					return ret;
363 			}
364 
365 			if (old_s) {
366 				int ret = bch2_trans_mark_stripe_bucket(trans,
367 						bkey_s_c_to_stripe(old), i, true);
368 				if (ret)
369 					return ret;
370 			}
371 		}
372 	}
373 
374 	if (flags & BTREE_TRIGGER_ATOMIC) {
375 		struct stripe *m = genradix_ptr(&c->stripes, idx);
376 
377 		if (!m) {
378 			struct printbuf buf1 = PRINTBUF;
379 			struct printbuf buf2 = PRINTBUF;
380 
381 			bch2_bkey_val_to_text(&buf1, c, old);
382 			bch2_bkey_val_to_text(&buf2, c, new);
383 			bch_err_ratelimited(c, "error marking nonexistent stripe %llu while marking\n"
384 					    "old %s\n"
385 					    "new %s", idx, buf1.buf, buf2.buf);
386 			printbuf_exit(&buf2);
387 			printbuf_exit(&buf1);
388 			bch2_inconsistent_error(c);
389 			return -1;
390 		}
391 
392 		if (!new_s) {
393 			bch2_stripes_heap_del(c, m, idx);
394 
395 			memset(m, 0, sizeof(*m));
396 		} else {
397 			m->sectors	= le16_to_cpu(new_s->sectors);
398 			m->algorithm	= new_s->algorithm;
399 			m->nr_blocks	= new_s->nr_blocks;
400 			m->nr_redundant	= new_s->nr_redundant;
401 			m->blocks_nonempty = 0;
402 
403 			for (unsigned i = 0; i < new_s->nr_blocks; i++)
404 				m->blocks_nonempty += !!stripe_blockcount_get(new_s, i);
405 
406 			if (!old_s)
407 				bch2_stripes_heap_insert(c, m, idx);
408 			else
409 				bch2_stripes_heap_update(c, m, idx);
410 		}
411 	}
412 
413 	if (flags & BTREE_TRIGGER_GC) {
414 		struct gc_stripe *m =
415 			genradix_ptr_alloc(&c->gc_stripes, idx, GFP_KERNEL);
416 
417 		if (!m) {
418 			bch_err(c, "error allocating memory for gc_stripes, idx %llu",
419 				idx);
420 			return -BCH_ERR_ENOMEM_mark_stripe;
421 		}
422 		/*
423 		 * This will be wrong when we bring back runtime gc: we should
424 		 * be unmarking the old key and then marking the new key
425 		 */
426 		m->alive	= true;
427 		m->sectors	= le16_to_cpu(new_s->sectors);
428 		m->nr_blocks	= new_s->nr_blocks;
429 		m->nr_redundant	= new_s->nr_redundant;
430 
431 		for (unsigned i = 0; i < new_s->nr_blocks; i++)
432 			m->ptrs[i] = new_s->ptrs[i];
433 
434 		bch2_bkey_to_replicas(&m->r.e, new);
435 
436 		/*
437 		 * gc recalculates this field from stripe ptr
438 		 * references:
439 		 */
440 		memset(m->block_sectors, 0, sizeof(m->block_sectors));
441 
442 		for (unsigned i = 0; i < new_s->nr_blocks; i++) {
443 			int ret = mark_stripe_bucket(trans, new, i, flags);
444 			if (ret)
445 				return ret;
446 		}
447 
448 		int ret = bch2_update_replicas(c, new, &m->r.e,
449 				      ((s64) m->sectors * m->nr_redundant),
450 				      0, true);
451 		if (ret) {
452 			struct printbuf buf = PRINTBUF;
453 
454 			bch2_bkey_val_to_text(&buf, c, new);
455 			bch2_fs_fatal_error(c, ": no replicas entry for %s", buf.buf);
456 			printbuf_exit(&buf);
457 			return ret;
458 		}
459 	}
460 
461 	return 0;
462 }
463 
464 /* returns blocknr in stripe that we matched: */
465 static const struct bch_extent_ptr *bkey_matches_stripe(struct bch_stripe *s,
466 						struct bkey_s_c k, unsigned *block)
467 {
468 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
469 	unsigned i, nr_data = s->nr_blocks - s->nr_redundant;
470 
471 	bkey_for_each_ptr(ptrs, ptr)
472 		for (i = 0; i < nr_data; i++)
473 			if (__bch2_ptr_matches_stripe(&s->ptrs[i], ptr,
474 						      le16_to_cpu(s->sectors))) {
475 				*block = i;
476 				return ptr;
477 			}
478 
479 	return NULL;
480 }
481 
482 static bool extent_has_stripe_ptr(struct bkey_s_c k, u64 idx)
483 {
484 	switch (k.k->type) {
485 	case KEY_TYPE_extent: {
486 		struct bkey_s_c_extent e = bkey_s_c_to_extent(k);
487 		const union bch_extent_entry *entry;
488 
489 		extent_for_each_entry(e, entry)
490 			if (extent_entry_type(entry) ==
491 			    BCH_EXTENT_ENTRY_stripe_ptr &&
492 			    entry->stripe_ptr.idx == idx)
493 				return true;
494 
495 		break;
496 	}
497 	}
498 
499 	return false;
500 }
501 
502 /* Stripe bufs: */
503 
504 static void ec_stripe_buf_exit(struct ec_stripe_buf *buf)
505 {
506 	if (buf->key.k.type == KEY_TYPE_stripe) {
507 		struct bkey_i_stripe *s = bkey_i_to_stripe(&buf->key);
508 		unsigned i;
509 
510 		for (i = 0; i < s->v.nr_blocks; i++) {
511 			kvfree(buf->data[i]);
512 			buf->data[i] = NULL;
513 		}
514 	}
515 }
516 
517 /* XXX: this is a non-mempoolified memory allocation: */
518 static int ec_stripe_buf_init(struct ec_stripe_buf *buf,
519 			      unsigned offset, unsigned size)
520 {
521 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
522 	unsigned csum_granularity = 1U << v->csum_granularity_bits;
523 	unsigned end = offset + size;
524 	unsigned i;
525 
526 	BUG_ON(end > le16_to_cpu(v->sectors));
527 
528 	offset	= round_down(offset, csum_granularity);
529 	end	= min_t(unsigned, le16_to_cpu(v->sectors),
530 			round_up(end, csum_granularity));
531 
532 	buf->offset	= offset;
533 	buf->size	= end - offset;
534 
535 	memset(buf->valid, 0xFF, sizeof(buf->valid));
536 
537 	for (i = 0; i < v->nr_blocks; i++) {
538 		buf->data[i] = kvmalloc(buf->size << 9, GFP_KERNEL);
539 		if (!buf->data[i])
540 			goto err;
541 	}
542 
543 	return 0;
544 err:
545 	ec_stripe_buf_exit(buf);
546 	return -BCH_ERR_ENOMEM_stripe_buf;
547 }
548 
549 /* Checksumming: */
550 
551 static struct bch_csum ec_block_checksum(struct ec_stripe_buf *buf,
552 					 unsigned block, unsigned offset)
553 {
554 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
555 	unsigned csum_granularity = 1 << v->csum_granularity_bits;
556 	unsigned end = buf->offset + buf->size;
557 	unsigned len = min(csum_granularity, end - offset);
558 
559 	BUG_ON(offset >= end);
560 	BUG_ON(offset <  buf->offset);
561 	BUG_ON(offset & (csum_granularity - 1));
562 	BUG_ON(offset + len != le16_to_cpu(v->sectors) &&
563 	       (len & (csum_granularity - 1)));
564 
565 	return bch2_checksum(NULL, v->csum_type,
566 			     null_nonce(),
567 			     buf->data[block] + ((offset - buf->offset) << 9),
568 			     len << 9);
569 }
570 
571 static void ec_generate_checksums(struct ec_stripe_buf *buf)
572 {
573 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
574 	unsigned i, j, csums_per_device = stripe_csums_per_device(v);
575 
576 	if (!v->csum_type)
577 		return;
578 
579 	BUG_ON(buf->offset);
580 	BUG_ON(buf->size != le16_to_cpu(v->sectors));
581 
582 	for (i = 0; i < v->nr_blocks; i++)
583 		for (j = 0; j < csums_per_device; j++)
584 			stripe_csum_set(v, i, j,
585 				ec_block_checksum(buf, i, j << v->csum_granularity_bits));
586 }
587 
588 static void ec_validate_checksums(struct bch_fs *c, struct ec_stripe_buf *buf)
589 {
590 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
591 	unsigned csum_granularity = 1 << v->csum_granularity_bits;
592 	unsigned i;
593 
594 	if (!v->csum_type)
595 		return;
596 
597 	for (i = 0; i < v->nr_blocks; i++) {
598 		unsigned offset = buf->offset;
599 		unsigned end = buf->offset + buf->size;
600 
601 		if (!test_bit(i, buf->valid))
602 			continue;
603 
604 		while (offset < end) {
605 			unsigned j = offset >> v->csum_granularity_bits;
606 			unsigned len = min(csum_granularity, end - offset);
607 			struct bch_csum want = stripe_csum_get(v, i, j);
608 			struct bch_csum got = ec_block_checksum(buf, i, offset);
609 
610 			if (bch2_crc_cmp(want, got)) {
611 				struct printbuf err = PRINTBUF;
612 				struct bch_dev *ca = bch_dev_bkey_exists(c, v->ptrs[i].dev);
613 
614 				prt_str(&err, "stripe ");
615 				bch2_csum_err_msg(&err, v->csum_type, want, got);
616 				prt_printf(&err, "  for %ps at %u of\n  ", (void *) _RET_IP_, i);
617 				bch2_bkey_val_to_text(&err, c, bkey_i_to_s_c(&buf->key));
618 				bch_err_ratelimited(ca, "%s", err.buf);
619 				printbuf_exit(&err);
620 
621 				clear_bit(i, buf->valid);
622 
623 				bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
624 				break;
625 			}
626 
627 			offset += len;
628 		}
629 	}
630 }
631 
632 /* Erasure coding: */
633 
634 static void ec_generate_ec(struct ec_stripe_buf *buf)
635 {
636 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
637 	unsigned nr_data = v->nr_blocks - v->nr_redundant;
638 	unsigned bytes = le16_to_cpu(v->sectors) << 9;
639 
640 	raid_gen(nr_data, v->nr_redundant, bytes, buf->data);
641 }
642 
643 static unsigned ec_nr_failed(struct ec_stripe_buf *buf)
644 {
645 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
646 
647 	return v->nr_blocks - bitmap_weight(buf->valid, v->nr_blocks);
648 }
649 
650 static int ec_do_recov(struct bch_fs *c, struct ec_stripe_buf *buf)
651 {
652 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
653 	unsigned i, failed[BCH_BKEY_PTRS_MAX], nr_failed = 0;
654 	unsigned nr_data = v->nr_blocks - v->nr_redundant;
655 	unsigned bytes = buf->size << 9;
656 
657 	if (ec_nr_failed(buf) > v->nr_redundant) {
658 		bch_err_ratelimited(c,
659 			"error doing reconstruct read: unable to read enough blocks");
660 		return -1;
661 	}
662 
663 	for (i = 0; i < nr_data; i++)
664 		if (!test_bit(i, buf->valid))
665 			failed[nr_failed++] = i;
666 
667 	raid_rec(nr_failed, failed, nr_data, v->nr_redundant, bytes, buf->data);
668 	return 0;
669 }
670 
671 /* IO: */
672 
673 static void ec_block_endio(struct bio *bio)
674 {
675 	struct ec_bio *ec_bio = container_of(bio, struct ec_bio, bio);
676 	struct bch_stripe *v = &bkey_i_to_stripe(&ec_bio->buf->key)->v;
677 	struct bch_extent_ptr *ptr = &v->ptrs[ec_bio->idx];
678 	struct bch_dev *ca = ec_bio->ca;
679 	struct closure *cl = bio->bi_private;
680 
681 	if (bch2_dev_io_err_on(bio->bi_status, ca,
682 			       bio_data_dir(bio)
683 			       ? BCH_MEMBER_ERROR_write
684 			       : BCH_MEMBER_ERROR_read,
685 			       "erasure coding %s error: %s",
686 			       bio_data_dir(bio) ? "write" : "read",
687 			       bch2_blk_status_to_str(bio->bi_status)))
688 		clear_bit(ec_bio->idx, ec_bio->buf->valid);
689 
690 	if (ptr_stale(ca, ptr)) {
691 		bch_err_ratelimited(ca->fs,
692 				    "error %s stripe: stale pointer after io",
693 				    bio_data_dir(bio) == READ ? "reading from" : "writing to");
694 		clear_bit(ec_bio->idx, ec_bio->buf->valid);
695 	}
696 
697 	bio_put(&ec_bio->bio);
698 	percpu_ref_put(&ca->io_ref);
699 	closure_put(cl);
700 }
701 
702 static void ec_block_io(struct bch_fs *c, struct ec_stripe_buf *buf,
703 			blk_opf_t opf, unsigned idx, struct closure *cl)
704 {
705 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
706 	unsigned offset = 0, bytes = buf->size << 9;
707 	struct bch_extent_ptr *ptr = &v->ptrs[idx];
708 	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
709 	enum bch_data_type data_type = idx < v->nr_blocks - v->nr_redundant
710 		? BCH_DATA_user
711 		: BCH_DATA_parity;
712 	int rw = op_is_write(opf);
713 
714 	if (ptr_stale(ca, ptr)) {
715 		bch_err_ratelimited(c,
716 				    "error %s stripe: stale pointer",
717 				    rw == READ ? "reading from" : "writing to");
718 		clear_bit(idx, buf->valid);
719 		return;
720 	}
721 
722 	if (!bch2_dev_get_ioref(ca, rw)) {
723 		clear_bit(idx, buf->valid);
724 		return;
725 	}
726 
727 	this_cpu_add(ca->io_done->sectors[rw][data_type], buf->size);
728 
729 	while (offset < bytes) {
730 		unsigned nr_iovecs = min_t(size_t, BIO_MAX_VECS,
731 					   DIV_ROUND_UP(bytes, PAGE_SIZE));
732 		unsigned b = min_t(size_t, bytes - offset,
733 				   nr_iovecs << PAGE_SHIFT);
734 		struct ec_bio *ec_bio;
735 
736 		ec_bio = container_of(bio_alloc_bioset(ca->disk_sb.bdev,
737 						       nr_iovecs,
738 						       opf,
739 						       GFP_KERNEL,
740 						       &c->ec_bioset),
741 				      struct ec_bio, bio);
742 
743 		ec_bio->ca			= ca;
744 		ec_bio->buf			= buf;
745 		ec_bio->idx			= idx;
746 
747 		ec_bio->bio.bi_iter.bi_sector	= ptr->offset + buf->offset + (offset >> 9);
748 		ec_bio->bio.bi_end_io		= ec_block_endio;
749 		ec_bio->bio.bi_private		= cl;
750 
751 		bch2_bio_map(&ec_bio->bio, buf->data[idx] + offset, b);
752 
753 		closure_get(cl);
754 		percpu_ref_get(&ca->io_ref);
755 
756 		submit_bio(&ec_bio->bio);
757 
758 		offset += b;
759 	}
760 
761 	percpu_ref_put(&ca->io_ref);
762 }
763 
764 static int get_stripe_key_trans(struct btree_trans *trans, u64 idx,
765 				struct ec_stripe_buf *stripe)
766 {
767 	struct btree_iter iter;
768 	struct bkey_s_c k;
769 	int ret;
770 
771 	k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_stripes,
772 			       POS(0, idx), BTREE_ITER_SLOTS);
773 	ret = bkey_err(k);
774 	if (ret)
775 		goto err;
776 	if (k.k->type != KEY_TYPE_stripe) {
777 		ret = -ENOENT;
778 		goto err;
779 	}
780 	bkey_reassemble(&stripe->key, k);
781 err:
782 	bch2_trans_iter_exit(trans, &iter);
783 	return ret;
784 }
785 
786 /* recovery read path: */
787 int bch2_ec_read_extent(struct btree_trans *trans, struct bch_read_bio *rbio)
788 {
789 	struct bch_fs *c = trans->c;
790 	struct ec_stripe_buf *buf;
791 	struct closure cl;
792 	struct bch_stripe *v;
793 	unsigned i, offset;
794 	int ret = 0;
795 
796 	closure_init_stack(&cl);
797 
798 	BUG_ON(!rbio->pick.has_ec);
799 
800 	buf = kzalloc(sizeof(*buf), GFP_NOFS);
801 	if (!buf)
802 		return -BCH_ERR_ENOMEM_ec_read_extent;
803 
804 	ret = lockrestart_do(trans, get_stripe_key_trans(trans, rbio->pick.ec.idx, buf));
805 	if (ret) {
806 		bch_err_ratelimited(c,
807 			"error doing reconstruct read: error %i looking up stripe", ret);
808 		kfree(buf);
809 		return -EIO;
810 	}
811 
812 	v = &bkey_i_to_stripe(&buf->key)->v;
813 
814 	if (!bch2_ptr_matches_stripe(v, rbio->pick)) {
815 		bch_err_ratelimited(c,
816 			"error doing reconstruct read: pointer doesn't match stripe");
817 		ret = -EIO;
818 		goto err;
819 	}
820 
821 	offset = rbio->bio.bi_iter.bi_sector - v->ptrs[rbio->pick.ec.block].offset;
822 	if (offset + bio_sectors(&rbio->bio) > le16_to_cpu(v->sectors)) {
823 		bch_err_ratelimited(c,
824 			"error doing reconstruct read: read is bigger than stripe");
825 		ret = -EIO;
826 		goto err;
827 	}
828 
829 	ret = ec_stripe_buf_init(buf, offset, bio_sectors(&rbio->bio));
830 	if (ret)
831 		goto err;
832 
833 	for (i = 0; i < v->nr_blocks; i++)
834 		ec_block_io(c, buf, REQ_OP_READ, i, &cl);
835 
836 	closure_sync(&cl);
837 
838 	if (ec_nr_failed(buf) > v->nr_redundant) {
839 		bch_err_ratelimited(c,
840 			"error doing reconstruct read: unable to read enough blocks");
841 		ret = -EIO;
842 		goto err;
843 	}
844 
845 	ec_validate_checksums(c, buf);
846 
847 	ret = ec_do_recov(c, buf);
848 	if (ret)
849 		goto err;
850 
851 	memcpy_to_bio(&rbio->bio, rbio->bio.bi_iter,
852 		      buf->data[rbio->pick.ec.block] + ((offset - buf->offset) << 9));
853 err:
854 	ec_stripe_buf_exit(buf);
855 	kfree(buf);
856 	return ret;
857 }
858 
859 /* stripe bucket accounting: */
860 
861 static int __ec_stripe_mem_alloc(struct bch_fs *c, size_t idx, gfp_t gfp)
862 {
863 	ec_stripes_heap n, *h = &c->ec_stripes_heap;
864 
865 	if (idx >= h->size) {
866 		if (!init_heap(&n, max(1024UL, roundup_pow_of_two(idx + 1)), gfp))
867 			return -BCH_ERR_ENOMEM_ec_stripe_mem_alloc;
868 
869 		mutex_lock(&c->ec_stripes_heap_lock);
870 		if (n.size > h->size) {
871 			memcpy(n.data, h->data, h->used * sizeof(h->data[0]));
872 			n.used = h->used;
873 			swap(*h, n);
874 		}
875 		mutex_unlock(&c->ec_stripes_heap_lock);
876 
877 		free_heap(&n);
878 	}
879 
880 	if (!genradix_ptr_alloc(&c->stripes, idx, gfp))
881 		return -BCH_ERR_ENOMEM_ec_stripe_mem_alloc;
882 
883 	if (c->gc_pos.phase != GC_PHASE_NOT_RUNNING &&
884 	    !genradix_ptr_alloc(&c->gc_stripes, idx, gfp))
885 		return -BCH_ERR_ENOMEM_ec_stripe_mem_alloc;
886 
887 	return 0;
888 }
889 
890 static int ec_stripe_mem_alloc(struct btree_trans *trans,
891 			       struct btree_iter *iter)
892 {
893 	return allocate_dropping_locks_errcode(trans,
894 			__ec_stripe_mem_alloc(trans->c, iter->pos.offset, _gfp));
895 }
896 
897 /*
898  * Hash table of open stripes:
899  * Stripes that are being created or modified are kept in a hash table, so that
900  * stripe deletion can skip them.
901  */
902 
903 static bool __bch2_stripe_is_open(struct bch_fs *c, u64 idx)
904 {
905 	unsigned hash = hash_64(idx, ilog2(ARRAY_SIZE(c->ec_stripes_new)));
906 	struct ec_stripe_new *s;
907 
908 	hlist_for_each_entry(s, &c->ec_stripes_new[hash], hash)
909 		if (s->idx == idx)
910 			return true;
911 	return false;
912 }
913 
914 static bool bch2_stripe_is_open(struct bch_fs *c, u64 idx)
915 {
916 	bool ret = false;
917 
918 	spin_lock(&c->ec_stripes_new_lock);
919 	ret = __bch2_stripe_is_open(c, idx);
920 	spin_unlock(&c->ec_stripes_new_lock);
921 
922 	return ret;
923 }
924 
925 static bool bch2_try_open_stripe(struct bch_fs *c,
926 				 struct ec_stripe_new *s,
927 				 u64 idx)
928 {
929 	bool ret;
930 
931 	spin_lock(&c->ec_stripes_new_lock);
932 	ret = !__bch2_stripe_is_open(c, idx);
933 	if (ret) {
934 		unsigned hash = hash_64(idx, ilog2(ARRAY_SIZE(c->ec_stripes_new)));
935 
936 		s->idx = idx;
937 		hlist_add_head(&s->hash, &c->ec_stripes_new[hash]);
938 	}
939 	spin_unlock(&c->ec_stripes_new_lock);
940 
941 	return ret;
942 }
943 
944 static void bch2_stripe_close(struct bch_fs *c, struct ec_stripe_new *s)
945 {
946 	BUG_ON(!s->idx);
947 
948 	spin_lock(&c->ec_stripes_new_lock);
949 	hlist_del_init(&s->hash);
950 	spin_unlock(&c->ec_stripes_new_lock);
951 
952 	s->idx = 0;
953 }
954 
955 /* Heap of all existing stripes, ordered by blocks_nonempty */
956 
957 static u64 stripe_idx_to_delete(struct bch_fs *c)
958 {
959 	ec_stripes_heap *h = &c->ec_stripes_heap;
960 
961 	lockdep_assert_held(&c->ec_stripes_heap_lock);
962 
963 	if (h->used &&
964 	    h->data[0].blocks_nonempty == 0 &&
965 	    !bch2_stripe_is_open(c, h->data[0].idx))
966 		return h->data[0].idx;
967 
968 	return 0;
969 }
970 
971 static inline int ec_stripes_heap_cmp(ec_stripes_heap *h,
972 				      struct ec_stripe_heap_entry l,
973 				      struct ec_stripe_heap_entry r)
974 {
975 	return ((l.blocks_nonempty > r.blocks_nonempty) -
976 		(l.blocks_nonempty < r.blocks_nonempty));
977 }
978 
979 static inline void ec_stripes_heap_set_backpointer(ec_stripes_heap *h,
980 						   size_t i)
981 {
982 	struct bch_fs *c = container_of(h, struct bch_fs, ec_stripes_heap);
983 
984 	genradix_ptr(&c->stripes, h->data[i].idx)->heap_idx = i;
985 }
986 
987 static void heap_verify_backpointer(struct bch_fs *c, size_t idx)
988 {
989 	ec_stripes_heap *h = &c->ec_stripes_heap;
990 	struct stripe *m = genradix_ptr(&c->stripes, idx);
991 
992 	BUG_ON(m->heap_idx >= h->used);
993 	BUG_ON(h->data[m->heap_idx].idx != idx);
994 }
995 
996 void bch2_stripes_heap_del(struct bch_fs *c,
997 			   struct stripe *m, size_t idx)
998 {
999 	mutex_lock(&c->ec_stripes_heap_lock);
1000 	heap_verify_backpointer(c, idx);
1001 
1002 	heap_del(&c->ec_stripes_heap, m->heap_idx,
1003 		 ec_stripes_heap_cmp,
1004 		 ec_stripes_heap_set_backpointer);
1005 	mutex_unlock(&c->ec_stripes_heap_lock);
1006 }
1007 
1008 void bch2_stripes_heap_insert(struct bch_fs *c,
1009 			      struct stripe *m, size_t idx)
1010 {
1011 	mutex_lock(&c->ec_stripes_heap_lock);
1012 	BUG_ON(heap_full(&c->ec_stripes_heap));
1013 
1014 	heap_add(&c->ec_stripes_heap, ((struct ec_stripe_heap_entry) {
1015 			.idx = idx,
1016 			.blocks_nonempty = m->blocks_nonempty,
1017 		}),
1018 		 ec_stripes_heap_cmp,
1019 		 ec_stripes_heap_set_backpointer);
1020 
1021 	heap_verify_backpointer(c, idx);
1022 	mutex_unlock(&c->ec_stripes_heap_lock);
1023 }
1024 
1025 void bch2_stripes_heap_update(struct bch_fs *c,
1026 			      struct stripe *m, size_t idx)
1027 {
1028 	ec_stripes_heap *h = &c->ec_stripes_heap;
1029 	bool do_deletes;
1030 	size_t i;
1031 
1032 	mutex_lock(&c->ec_stripes_heap_lock);
1033 	heap_verify_backpointer(c, idx);
1034 
1035 	h->data[m->heap_idx].blocks_nonempty = m->blocks_nonempty;
1036 
1037 	i = m->heap_idx;
1038 	heap_sift_up(h,	  i, ec_stripes_heap_cmp,
1039 		     ec_stripes_heap_set_backpointer);
1040 	heap_sift_down(h, i, ec_stripes_heap_cmp,
1041 		       ec_stripes_heap_set_backpointer);
1042 
1043 	heap_verify_backpointer(c, idx);
1044 
1045 	do_deletes = stripe_idx_to_delete(c) != 0;
1046 	mutex_unlock(&c->ec_stripes_heap_lock);
1047 
1048 	if (do_deletes)
1049 		bch2_do_stripe_deletes(c);
1050 }
1051 
1052 /* stripe deletion */
1053 
1054 static int ec_stripe_delete(struct btree_trans *trans, u64 idx)
1055 {
1056 	struct bch_fs *c = trans->c;
1057 	struct btree_iter iter;
1058 	struct bkey_s_c k;
1059 	struct bkey_s_c_stripe s;
1060 	int ret;
1061 
1062 	k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_stripes, POS(0, idx),
1063 			       BTREE_ITER_INTENT);
1064 	ret = bkey_err(k);
1065 	if (ret)
1066 		goto err;
1067 
1068 	if (k.k->type != KEY_TYPE_stripe) {
1069 		bch2_fs_inconsistent(c, "attempting to delete nonexistent stripe %llu", idx);
1070 		ret = -EINVAL;
1071 		goto err;
1072 	}
1073 
1074 	s = bkey_s_c_to_stripe(k);
1075 	for (unsigned i = 0; i < s.v->nr_blocks; i++)
1076 		if (stripe_blockcount_get(s.v, i)) {
1077 			struct printbuf buf = PRINTBUF;
1078 
1079 			bch2_bkey_val_to_text(&buf, c, k);
1080 			bch2_fs_inconsistent(c, "attempting to delete nonempty stripe %s", buf.buf);
1081 			printbuf_exit(&buf);
1082 			ret = -EINVAL;
1083 			goto err;
1084 		}
1085 
1086 	ret = bch2_btree_delete_at(trans, &iter, 0);
1087 err:
1088 	bch2_trans_iter_exit(trans, &iter);
1089 	return ret;
1090 }
1091 
1092 static void ec_stripe_delete_work(struct work_struct *work)
1093 {
1094 	struct bch_fs *c =
1095 		container_of(work, struct bch_fs, ec_stripe_delete_work);
1096 
1097 	while (1) {
1098 		mutex_lock(&c->ec_stripes_heap_lock);
1099 		u64 idx = stripe_idx_to_delete(c);
1100 		mutex_unlock(&c->ec_stripes_heap_lock);
1101 
1102 		if (!idx)
1103 			break;
1104 
1105 		int ret = bch2_trans_do(c, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
1106 					ec_stripe_delete(trans, idx));
1107 		bch_err_fn(c, ret);
1108 		if (ret)
1109 			break;
1110 	}
1111 
1112 	bch2_write_ref_put(c, BCH_WRITE_REF_stripe_delete);
1113 }
1114 
1115 void bch2_do_stripe_deletes(struct bch_fs *c)
1116 {
1117 	if (bch2_write_ref_tryget(c, BCH_WRITE_REF_stripe_delete) &&
1118 	    !queue_work(c->write_ref_wq, &c->ec_stripe_delete_work))
1119 		bch2_write_ref_put(c, BCH_WRITE_REF_stripe_delete);
1120 }
1121 
1122 /* stripe creation: */
1123 
1124 static int ec_stripe_key_update(struct btree_trans *trans,
1125 				struct bkey_i_stripe *new,
1126 				bool create)
1127 {
1128 	struct bch_fs *c = trans->c;
1129 	struct btree_iter iter;
1130 	struct bkey_s_c k;
1131 	int ret;
1132 
1133 	k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_stripes,
1134 			       new->k.p, BTREE_ITER_INTENT);
1135 	ret = bkey_err(k);
1136 	if (ret)
1137 		goto err;
1138 
1139 	if (k.k->type != (create ? KEY_TYPE_deleted : KEY_TYPE_stripe)) {
1140 		bch2_fs_inconsistent(c, "error %s stripe: got existing key type %s",
1141 				     create ? "creating" : "updating",
1142 				     bch2_bkey_types[k.k->type]);
1143 		ret = -EINVAL;
1144 		goto err;
1145 	}
1146 
1147 	if (k.k->type == KEY_TYPE_stripe) {
1148 		const struct bch_stripe *old = bkey_s_c_to_stripe(k).v;
1149 		unsigned i;
1150 
1151 		if (old->nr_blocks != new->v.nr_blocks) {
1152 			bch_err(c, "error updating stripe: nr_blocks does not match");
1153 			ret = -EINVAL;
1154 			goto err;
1155 		}
1156 
1157 		for (i = 0; i < new->v.nr_blocks; i++) {
1158 			unsigned v = stripe_blockcount_get(old, i);
1159 
1160 			BUG_ON(v &&
1161 			       (old->ptrs[i].dev != new->v.ptrs[i].dev ||
1162 				old->ptrs[i].gen != new->v.ptrs[i].gen ||
1163 				old->ptrs[i].offset != new->v.ptrs[i].offset));
1164 
1165 			stripe_blockcount_set(&new->v, i, v);
1166 		}
1167 	}
1168 
1169 	ret = bch2_trans_update(trans, &iter, &new->k_i, 0);
1170 err:
1171 	bch2_trans_iter_exit(trans, &iter);
1172 	return ret;
1173 }
1174 
1175 static int ec_stripe_update_extent(struct btree_trans *trans,
1176 				   struct bpos bucket, u8 gen,
1177 				   struct ec_stripe_buf *s,
1178 				   struct bpos *bp_pos)
1179 {
1180 	struct bch_stripe *v = &bkey_i_to_stripe(&s->key)->v;
1181 	struct bch_fs *c = trans->c;
1182 	struct bch_backpointer bp;
1183 	struct btree_iter iter;
1184 	struct bkey_s_c k;
1185 	const struct bch_extent_ptr *ptr_c;
1186 	struct bch_extent_ptr *ptr, *ec_ptr = NULL;
1187 	struct bch_extent_stripe_ptr stripe_ptr;
1188 	struct bkey_i *n;
1189 	int ret, dev, block;
1190 
1191 	ret = bch2_get_next_backpointer(trans, bucket, gen,
1192 				bp_pos, &bp, BTREE_ITER_CACHED);
1193 	if (ret)
1194 		return ret;
1195 	if (bpos_eq(*bp_pos, SPOS_MAX))
1196 		return 0;
1197 
1198 	if (bp.level) {
1199 		struct printbuf buf = PRINTBUF;
1200 		struct btree_iter node_iter;
1201 		struct btree *b;
1202 
1203 		b = bch2_backpointer_get_node(trans, &node_iter, *bp_pos, bp);
1204 		bch2_trans_iter_exit(trans, &node_iter);
1205 
1206 		if (!b)
1207 			return 0;
1208 
1209 		prt_printf(&buf, "found btree node in erasure coded bucket: b=%px\n", b);
1210 		bch2_backpointer_to_text(&buf, &bp);
1211 
1212 		bch2_fs_inconsistent(c, "%s", buf.buf);
1213 		printbuf_exit(&buf);
1214 		return -EIO;
1215 	}
1216 
1217 	k = bch2_backpointer_get_key(trans, &iter, *bp_pos, bp, BTREE_ITER_INTENT);
1218 	ret = bkey_err(k);
1219 	if (ret)
1220 		return ret;
1221 	if (!k.k) {
1222 		/*
1223 		 * extent no longer exists - we could flush the btree
1224 		 * write buffer and retry to verify, but no need:
1225 		 */
1226 		return 0;
1227 	}
1228 
1229 	if (extent_has_stripe_ptr(k, s->key.k.p.offset))
1230 		goto out;
1231 
1232 	ptr_c = bkey_matches_stripe(v, k, &block);
1233 	/*
1234 	 * It doesn't generally make sense to erasure code cached ptrs:
1235 	 * XXX: should we be incrementing a counter?
1236 	 */
1237 	if (!ptr_c || ptr_c->cached)
1238 		goto out;
1239 
1240 	dev = v->ptrs[block].dev;
1241 
1242 	n = bch2_trans_kmalloc(trans, bkey_bytes(k.k) + sizeof(stripe_ptr));
1243 	ret = PTR_ERR_OR_ZERO(n);
1244 	if (ret)
1245 		goto out;
1246 
1247 	bkey_reassemble(n, k);
1248 
1249 	bch2_bkey_drop_ptrs(bkey_i_to_s(n), ptr, ptr->dev != dev);
1250 	ec_ptr = bch2_bkey_has_device(bkey_i_to_s(n), dev);
1251 	BUG_ON(!ec_ptr);
1252 
1253 	stripe_ptr = (struct bch_extent_stripe_ptr) {
1254 		.type = 1 << BCH_EXTENT_ENTRY_stripe_ptr,
1255 		.block		= block,
1256 		.redundancy	= v->nr_redundant,
1257 		.idx		= s->key.k.p.offset,
1258 	};
1259 
1260 	__extent_entry_insert(n,
1261 			(union bch_extent_entry *) ec_ptr,
1262 			(union bch_extent_entry *) &stripe_ptr);
1263 
1264 	ret = bch2_trans_update(trans, &iter, n, 0);
1265 out:
1266 	bch2_trans_iter_exit(trans, &iter);
1267 	return ret;
1268 }
1269 
1270 static int ec_stripe_update_bucket(struct btree_trans *trans, struct ec_stripe_buf *s,
1271 				   unsigned block)
1272 {
1273 	struct bch_fs *c = trans->c;
1274 	struct bch_stripe *v = &bkey_i_to_stripe(&s->key)->v;
1275 	struct bch_extent_ptr bucket = v->ptrs[block];
1276 	struct bpos bucket_pos = PTR_BUCKET_POS(c, &bucket);
1277 	struct bpos bp_pos = POS_MIN;
1278 	int ret = 0;
1279 
1280 	while (1) {
1281 		ret = commit_do(trans, NULL, NULL,
1282 				BCH_TRANS_COMMIT_no_check_rw|
1283 				BCH_TRANS_COMMIT_no_enospc,
1284 			ec_stripe_update_extent(trans, bucket_pos, bucket.gen,
1285 						s, &bp_pos));
1286 		if (ret)
1287 			break;
1288 		if (bkey_eq(bp_pos, POS_MAX))
1289 			break;
1290 
1291 		bp_pos = bpos_nosnap_successor(bp_pos);
1292 	}
1293 
1294 	return ret;
1295 }
1296 
1297 static int ec_stripe_update_extents(struct bch_fs *c, struct ec_stripe_buf *s)
1298 {
1299 	struct btree_trans *trans = bch2_trans_get(c);
1300 	struct bch_stripe *v = &bkey_i_to_stripe(&s->key)->v;
1301 	unsigned i, nr_data = v->nr_blocks - v->nr_redundant;
1302 	int ret = 0;
1303 
1304 	ret = bch2_btree_write_buffer_flush_sync(trans);
1305 	if (ret)
1306 		goto err;
1307 
1308 	for (i = 0; i < nr_data; i++) {
1309 		ret = ec_stripe_update_bucket(trans, s, i);
1310 		if (ret)
1311 			break;
1312 	}
1313 err:
1314 	bch2_trans_put(trans);
1315 
1316 	return ret;
1317 }
1318 
1319 static void zero_out_rest_of_ec_bucket(struct bch_fs *c,
1320 				       struct ec_stripe_new *s,
1321 				       unsigned block,
1322 				       struct open_bucket *ob)
1323 {
1324 	struct bch_dev *ca = bch_dev_bkey_exists(c, ob->dev);
1325 	unsigned offset = ca->mi.bucket_size - ob->sectors_free;
1326 	int ret;
1327 
1328 	if (!bch2_dev_get_ioref(ca, WRITE)) {
1329 		s->err = -BCH_ERR_erofs_no_writes;
1330 		return;
1331 	}
1332 
1333 	memset(s->new_stripe.data[block] + (offset << 9),
1334 	       0,
1335 	       ob->sectors_free << 9);
1336 
1337 	ret = blkdev_issue_zeroout(ca->disk_sb.bdev,
1338 			ob->bucket * ca->mi.bucket_size + offset,
1339 			ob->sectors_free,
1340 			GFP_KERNEL, 0);
1341 
1342 	percpu_ref_put(&ca->io_ref);
1343 
1344 	if (ret)
1345 		s->err = ret;
1346 }
1347 
1348 void bch2_ec_stripe_new_free(struct bch_fs *c, struct ec_stripe_new *s)
1349 {
1350 	if (s->idx)
1351 		bch2_stripe_close(c, s);
1352 	kfree(s);
1353 }
1354 
1355 /*
1356  * data buckets of new stripe all written: create the stripe
1357  */
1358 static void ec_stripe_create(struct ec_stripe_new *s)
1359 {
1360 	struct bch_fs *c = s->c;
1361 	struct open_bucket *ob;
1362 	struct bch_stripe *v = &bkey_i_to_stripe(&s->new_stripe.key)->v;
1363 	unsigned i, nr_data = v->nr_blocks - v->nr_redundant;
1364 	int ret;
1365 
1366 	BUG_ON(s->h->s == s);
1367 
1368 	closure_sync(&s->iodone);
1369 
1370 	if (!s->err) {
1371 		for (i = 0; i < nr_data; i++)
1372 			if (s->blocks[i]) {
1373 				ob = c->open_buckets + s->blocks[i];
1374 
1375 				if (ob->sectors_free)
1376 					zero_out_rest_of_ec_bucket(c, s, i, ob);
1377 			}
1378 	}
1379 
1380 	if (s->err) {
1381 		if (!bch2_err_matches(s->err, EROFS))
1382 			bch_err(c, "error creating stripe: error writing data buckets");
1383 		goto err;
1384 	}
1385 
1386 	if (s->have_existing_stripe) {
1387 		ec_validate_checksums(c, &s->existing_stripe);
1388 
1389 		if (ec_do_recov(c, &s->existing_stripe)) {
1390 			bch_err(c, "error creating stripe: error reading existing stripe");
1391 			goto err;
1392 		}
1393 
1394 		for (i = 0; i < nr_data; i++)
1395 			if (stripe_blockcount_get(&bkey_i_to_stripe(&s->existing_stripe.key)->v, i))
1396 				swap(s->new_stripe.data[i],
1397 				     s->existing_stripe.data[i]);
1398 
1399 		ec_stripe_buf_exit(&s->existing_stripe);
1400 	}
1401 
1402 	BUG_ON(!s->allocated);
1403 	BUG_ON(!s->idx);
1404 
1405 	ec_generate_ec(&s->new_stripe);
1406 
1407 	ec_generate_checksums(&s->new_stripe);
1408 
1409 	/* write p/q: */
1410 	for (i = nr_data; i < v->nr_blocks; i++)
1411 		ec_block_io(c, &s->new_stripe, REQ_OP_WRITE, i, &s->iodone);
1412 	closure_sync(&s->iodone);
1413 
1414 	if (ec_nr_failed(&s->new_stripe)) {
1415 		bch_err(c, "error creating stripe: error writing redundancy buckets");
1416 		goto err;
1417 	}
1418 
1419 	ret = bch2_trans_do(c, &s->res, NULL,
1420 			    BCH_TRANS_COMMIT_no_check_rw|
1421 			    BCH_TRANS_COMMIT_no_enospc,
1422 			    ec_stripe_key_update(trans,
1423 					bkey_i_to_stripe(&s->new_stripe.key),
1424 					!s->have_existing_stripe));
1425 	bch_err_msg(c, ret, "creating stripe key");
1426 	if (ret) {
1427 		goto err;
1428 	}
1429 
1430 	ret = ec_stripe_update_extents(c, &s->new_stripe);
1431 	bch_err_msg(c, ret, "error updating extents");
1432 	if (ret)
1433 		goto err;
1434 err:
1435 	bch2_disk_reservation_put(c, &s->res);
1436 
1437 	for (i = 0; i < v->nr_blocks; i++)
1438 		if (s->blocks[i]) {
1439 			ob = c->open_buckets + s->blocks[i];
1440 
1441 			if (i < nr_data) {
1442 				ob->ec = NULL;
1443 				__bch2_open_bucket_put(c, ob);
1444 			} else {
1445 				bch2_open_bucket_put(c, ob);
1446 			}
1447 		}
1448 
1449 	mutex_lock(&c->ec_stripe_new_lock);
1450 	list_del(&s->list);
1451 	mutex_unlock(&c->ec_stripe_new_lock);
1452 	wake_up(&c->ec_stripe_new_wait);
1453 
1454 	ec_stripe_buf_exit(&s->existing_stripe);
1455 	ec_stripe_buf_exit(&s->new_stripe);
1456 	closure_debug_destroy(&s->iodone);
1457 
1458 	ec_stripe_new_put(c, s, STRIPE_REF_stripe);
1459 }
1460 
1461 static struct ec_stripe_new *get_pending_stripe(struct bch_fs *c)
1462 {
1463 	struct ec_stripe_new *s;
1464 
1465 	mutex_lock(&c->ec_stripe_new_lock);
1466 	list_for_each_entry(s, &c->ec_stripe_new_list, list)
1467 		if (!atomic_read(&s->ref[STRIPE_REF_io]))
1468 			goto out;
1469 	s = NULL;
1470 out:
1471 	mutex_unlock(&c->ec_stripe_new_lock);
1472 
1473 	return s;
1474 }
1475 
1476 static void ec_stripe_create_work(struct work_struct *work)
1477 {
1478 	struct bch_fs *c = container_of(work,
1479 		struct bch_fs, ec_stripe_create_work);
1480 	struct ec_stripe_new *s;
1481 
1482 	while ((s = get_pending_stripe(c)))
1483 		ec_stripe_create(s);
1484 
1485 	bch2_write_ref_put(c, BCH_WRITE_REF_stripe_create);
1486 }
1487 
1488 void bch2_ec_do_stripe_creates(struct bch_fs *c)
1489 {
1490 	bch2_write_ref_get(c, BCH_WRITE_REF_stripe_create);
1491 
1492 	if (!queue_work(system_long_wq, &c->ec_stripe_create_work))
1493 		bch2_write_ref_put(c, BCH_WRITE_REF_stripe_create);
1494 }
1495 
1496 static void ec_stripe_set_pending(struct bch_fs *c, struct ec_stripe_head *h)
1497 {
1498 	struct ec_stripe_new *s = h->s;
1499 
1500 	BUG_ON(!s->allocated && !s->err);
1501 
1502 	h->s		= NULL;
1503 	s->pending	= true;
1504 
1505 	mutex_lock(&c->ec_stripe_new_lock);
1506 	list_add(&s->list, &c->ec_stripe_new_list);
1507 	mutex_unlock(&c->ec_stripe_new_lock);
1508 
1509 	ec_stripe_new_put(c, s, STRIPE_REF_io);
1510 }
1511 
1512 void bch2_ec_bucket_cancel(struct bch_fs *c, struct open_bucket *ob)
1513 {
1514 	struct ec_stripe_new *s = ob->ec;
1515 
1516 	s->err = -EIO;
1517 }
1518 
1519 void *bch2_writepoint_ec_buf(struct bch_fs *c, struct write_point *wp)
1520 {
1521 	struct open_bucket *ob = ec_open_bucket(c, &wp->ptrs);
1522 	struct bch_dev *ca;
1523 	unsigned offset;
1524 
1525 	if (!ob)
1526 		return NULL;
1527 
1528 	BUG_ON(!ob->ec->new_stripe.data[ob->ec_idx]);
1529 
1530 	ca	= bch_dev_bkey_exists(c, ob->dev);
1531 	offset	= ca->mi.bucket_size - ob->sectors_free;
1532 
1533 	return ob->ec->new_stripe.data[ob->ec_idx] + (offset << 9);
1534 }
1535 
1536 static int unsigned_cmp(const void *_l, const void *_r)
1537 {
1538 	unsigned l = *((const unsigned *) _l);
1539 	unsigned r = *((const unsigned *) _r);
1540 
1541 	return cmp_int(l, r);
1542 }
1543 
1544 /* pick most common bucket size: */
1545 static unsigned pick_blocksize(struct bch_fs *c,
1546 			       struct bch_devs_mask *devs)
1547 {
1548 	unsigned nr = 0, sizes[BCH_SB_MEMBERS_MAX];
1549 	struct {
1550 		unsigned nr, size;
1551 	} cur = { 0, 0 }, best = { 0, 0 };
1552 
1553 	for_each_member_device_rcu(c, ca, devs)
1554 		sizes[nr++] = ca->mi.bucket_size;
1555 
1556 	sort(sizes, nr, sizeof(unsigned), unsigned_cmp, NULL);
1557 
1558 	for (unsigned i = 0; i < nr; i++) {
1559 		if (sizes[i] != cur.size) {
1560 			if (cur.nr > best.nr)
1561 				best = cur;
1562 
1563 			cur.nr = 0;
1564 			cur.size = sizes[i];
1565 		}
1566 
1567 		cur.nr++;
1568 	}
1569 
1570 	if (cur.nr > best.nr)
1571 		best = cur;
1572 
1573 	return best.size;
1574 }
1575 
1576 static bool may_create_new_stripe(struct bch_fs *c)
1577 {
1578 	return false;
1579 }
1580 
1581 static void ec_stripe_key_init(struct bch_fs *c,
1582 			       struct bkey_i *k,
1583 			       unsigned nr_data,
1584 			       unsigned nr_parity,
1585 			       unsigned stripe_size)
1586 {
1587 	struct bkey_i_stripe *s = bkey_stripe_init(k);
1588 	unsigned u64s;
1589 
1590 	s->v.sectors			= cpu_to_le16(stripe_size);
1591 	s->v.algorithm			= 0;
1592 	s->v.nr_blocks			= nr_data + nr_parity;
1593 	s->v.nr_redundant		= nr_parity;
1594 	s->v.csum_granularity_bits	= ilog2(c->opts.encoded_extent_max >> 9);
1595 	s->v.csum_type			= BCH_CSUM_crc32c;
1596 	s->v.pad			= 0;
1597 
1598 	while ((u64s = stripe_val_u64s(&s->v)) > BKEY_VAL_U64s_MAX) {
1599 		BUG_ON(1 << s->v.csum_granularity_bits >=
1600 		       le16_to_cpu(s->v.sectors) ||
1601 		       s->v.csum_granularity_bits == U8_MAX);
1602 		s->v.csum_granularity_bits++;
1603 	}
1604 
1605 	set_bkey_val_u64s(&s->k, u64s);
1606 }
1607 
1608 static int ec_new_stripe_alloc(struct bch_fs *c, struct ec_stripe_head *h)
1609 {
1610 	struct ec_stripe_new *s;
1611 
1612 	lockdep_assert_held(&h->lock);
1613 
1614 	s = kzalloc(sizeof(*s), GFP_KERNEL);
1615 	if (!s)
1616 		return -BCH_ERR_ENOMEM_ec_new_stripe_alloc;
1617 
1618 	mutex_init(&s->lock);
1619 	closure_init(&s->iodone, NULL);
1620 	atomic_set(&s->ref[STRIPE_REF_stripe], 1);
1621 	atomic_set(&s->ref[STRIPE_REF_io], 1);
1622 	s->c		= c;
1623 	s->h		= h;
1624 	s->nr_data	= min_t(unsigned, h->nr_active_devs,
1625 				BCH_BKEY_PTRS_MAX) - h->redundancy;
1626 	s->nr_parity	= h->redundancy;
1627 
1628 	ec_stripe_key_init(c, &s->new_stripe.key,
1629 			   s->nr_data, s->nr_parity, h->blocksize);
1630 
1631 	h->s = s;
1632 	return 0;
1633 }
1634 
1635 static struct ec_stripe_head *
1636 ec_new_stripe_head_alloc(struct bch_fs *c, unsigned target,
1637 			 unsigned algo, unsigned redundancy,
1638 			 enum bch_watermark watermark)
1639 {
1640 	struct ec_stripe_head *h;
1641 
1642 	h = kzalloc(sizeof(*h), GFP_KERNEL);
1643 	if (!h)
1644 		return NULL;
1645 
1646 	mutex_init(&h->lock);
1647 	BUG_ON(!mutex_trylock(&h->lock));
1648 
1649 	h->target	= target;
1650 	h->algo		= algo;
1651 	h->redundancy	= redundancy;
1652 	h->watermark	= watermark;
1653 
1654 	rcu_read_lock();
1655 	h->devs = target_rw_devs(c, BCH_DATA_user, target);
1656 
1657 	for_each_member_device_rcu(c, ca, &h->devs)
1658 		if (!ca->mi.durability)
1659 			__clear_bit(ca->dev_idx, h->devs.d);
1660 
1661 	h->blocksize = pick_blocksize(c, &h->devs);
1662 
1663 	for_each_member_device_rcu(c, ca, &h->devs)
1664 		if (ca->mi.bucket_size == h->blocksize)
1665 			h->nr_active_devs++;
1666 
1667 	rcu_read_unlock();
1668 
1669 	/*
1670 	 * If we only have redundancy + 1 devices, we're better off with just
1671 	 * replication:
1672 	 */
1673 	if (h->nr_active_devs < h->redundancy + 2)
1674 		bch_err(c, "insufficient devices available to create stripe (have %u, need %u) - mismatched bucket sizes?",
1675 			h->nr_active_devs, h->redundancy + 2);
1676 
1677 	list_add(&h->list, &c->ec_stripe_head_list);
1678 	return h;
1679 }
1680 
1681 void bch2_ec_stripe_head_put(struct bch_fs *c, struct ec_stripe_head *h)
1682 {
1683 	if (h->s &&
1684 	    h->s->allocated &&
1685 	    bitmap_weight(h->s->blocks_allocated,
1686 			  h->s->nr_data) == h->s->nr_data)
1687 		ec_stripe_set_pending(c, h);
1688 
1689 	mutex_unlock(&h->lock);
1690 }
1691 
1692 static struct ec_stripe_head *
1693 __bch2_ec_stripe_head_get(struct btree_trans *trans,
1694 			  unsigned target,
1695 			  unsigned algo,
1696 			  unsigned redundancy,
1697 			  enum bch_watermark watermark)
1698 {
1699 	struct bch_fs *c = trans->c;
1700 	struct ec_stripe_head *h;
1701 	int ret;
1702 
1703 	if (!redundancy)
1704 		return NULL;
1705 
1706 	ret = bch2_trans_mutex_lock(trans, &c->ec_stripe_head_lock);
1707 	if (ret)
1708 		return ERR_PTR(ret);
1709 
1710 	if (test_bit(BCH_FS_going_ro, &c->flags)) {
1711 		h = ERR_PTR(-BCH_ERR_erofs_no_writes);
1712 		goto found;
1713 	}
1714 
1715 	list_for_each_entry(h, &c->ec_stripe_head_list, list)
1716 		if (h->target		== target &&
1717 		    h->algo		== algo &&
1718 		    h->redundancy	== redundancy &&
1719 		    h->watermark	== watermark) {
1720 			ret = bch2_trans_mutex_lock(trans, &h->lock);
1721 			if (ret)
1722 				h = ERR_PTR(ret);
1723 			goto found;
1724 		}
1725 
1726 	h = ec_new_stripe_head_alloc(c, target, algo, redundancy, watermark);
1727 found:
1728 	if (!IS_ERR_OR_NULL(h) &&
1729 	    h->nr_active_devs < h->redundancy + 2) {
1730 		mutex_unlock(&h->lock);
1731 		h = NULL;
1732 	}
1733 	mutex_unlock(&c->ec_stripe_head_lock);
1734 	return h;
1735 }
1736 
1737 static int new_stripe_alloc_buckets(struct btree_trans *trans, struct ec_stripe_head *h,
1738 				    enum bch_watermark watermark, struct closure *cl)
1739 {
1740 	struct bch_fs *c = trans->c;
1741 	struct bch_devs_mask devs = h->devs;
1742 	struct open_bucket *ob;
1743 	struct open_buckets buckets;
1744 	struct bch_stripe *v = &bkey_i_to_stripe(&h->s->new_stripe.key)->v;
1745 	unsigned i, j, nr_have_parity = 0, nr_have_data = 0;
1746 	bool have_cache = true;
1747 	int ret = 0;
1748 
1749 	BUG_ON(v->nr_blocks	!= h->s->nr_data + h->s->nr_parity);
1750 	BUG_ON(v->nr_redundant	!= h->s->nr_parity);
1751 
1752 	for_each_set_bit(i, h->s->blocks_gotten, v->nr_blocks) {
1753 		__clear_bit(v->ptrs[i].dev, devs.d);
1754 		if (i < h->s->nr_data)
1755 			nr_have_data++;
1756 		else
1757 			nr_have_parity++;
1758 	}
1759 
1760 	BUG_ON(nr_have_data	> h->s->nr_data);
1761 	BUG_ON(nr_have_parity	> h->s->nr_parity);
1762 
1763 	buckets.nr = 0;
1764 	if (nr_have_parity < h->s->nr_parity) {
1765 		ret = bch2_bucket_alloc_set_trans(trans, &buckets,
1766 					    &h->parity_stripe,
1767 					    &devs,
1768 					    h->s->nr_parity,
1769 					    &nr_have_parity,
1770 					    &have_cache, 0,
1771 					    BCH_DATA_parity,
1772 					    watermark,
1773 					    cl);
1774 
1775 		open_bucket_for_each(c, &buckets, ob, i) {
1776 			j = find_next_zero_bit(h->s->blocks_gotten,
1777 					       h->s->nr_data + h->s->nr_parity,
1778 					       h->s->nr_data);
1779 			BUG_ON(j >= h->s->nr_data + h->s->nr_parity);
1780 
1781 			h->s->blocks[j] = buckets.v[i];
1782 			v->ptrs[j] = bch2_ob_ptr(c, ob);
1783 			__set_bit(j, h->s->blocks_gotten);
1784 		}
1785 
1786 		if (ret)
1787 			return ret;
1788 	}
1789 
1790 	buckets.nr = 0;
1791 	if (nr_have_data < h->s->nr_data) {
1792 		ret = bch2_bucket_alloc_set_trans(trans, &buckets,
1793 					    &h->block_stripe,
1794 					    &devs,
1795 					    h->s->nr_data,
1796 					    &nr_have_data,
1797 					    &have_cache, 0,
1798 					    BCH_DATA_user,
1799 					    watermark,
1800 					    cl);
1801 
1802 		open_bucket_for_each(c, &buckets, ob, i) {
1803 			j = find_next_zero_bit(h->s->blocks_gotten,
1804 					       h->s->nr_data, 0);
1805 			BUG_ON(j >= h->s->nr_data);
1806 
1807 			h->s->blocks[j] = buckets.v[i];
1808 			v->ptrs[j] = bch2_ob_ptr(c, ob);
1809 			__set_bit(j, h->s->blocks_gotten);
1810 		}
1811 
1812 		if (ret)
1813 			return ret;
1814 	}
1815 
1816 	return 0;
1817 }
1818 
1819 /* XXX: doesn't obey target: */
1820 static s64 get_existing_stripe(struct bch_fs *c,
1821 			       struct ec_stripe_head *head)
1822 {
1823 	ec_stripes_heap *h = &c->ec_stripes_heap;
1824 	struct stripe *m;
1825 	size_t heap_idx;
1826 	u64 stripe_idx;
1827 	s64 ret = -1;
1828 
1829 	if (may_create_new_stripe(c))
1830 		return -1;
1831 
1832 	mutex_lock(&c->ec_stripes_heap_lock);
1833 	for (heap_idx = 0; heap_idx < h->used; heap_idx++) {
1834 		/* No blocks worth reusing, stripe will just be deleted: */
1835 		if (!h->data[heap_idx].blocks_nonempty)
1836 			continue;
1837 
1838 		stripe_idx = h->data[heap_idx].idx;
1839 
1840 		m = genradix_ptr(&c->stripes, stripe_idx);
1841 
1842 		if (m->algorithm	== head->algo &&
1843 		    m->nr_redundant	== head->redundancy &&
1844 		    m->sectors		== head->blocksize &&
1845 		    m->blocks_nonempty	< m->nr_blocks - m->nr_redundant &&
1846 		    bch2_try_open_stripe(c, head->s, stripe_idx)) {
1847 			ret = stripe_idx;
1848 			break;
1849 		}
1850 	}
1851 	mutex_unlock(&c->ec_stripes_heap_lock);
1852 	return ret;
1853 }
1854 
1855 static int __bch2_ec_stripe_head_reuse(struct btree_trans *trans, struct ec_stripe_head *h)
1856 {
1857 	struct bch_fs *c = trans->c;
1858 	struct bch_stripe *new_v = &bkey_i_to_stripe(&h->s->new_stripe.key)->v;
1859 	struct bch_stripe *existing_v;
1860 	unsigned i;
1861 	s64 idx;
1862 	int ret;
1863 
1864 	/*
1865 	 * If we can't allocate a new stripe, and there's no stripes with empty
1866 	 * blocks for us to reuse, that means we have to wait on copygc:
1867 	 */
1868 	idx = get_existing_stripe(c, h);
1869 	if (idx < 0)
1870 		return -BCH_ERR_stripe_alloc_blocked;
1871 
1872 	ret = get_stripe_key_trans(trans, idx, &h->s->existing_stripe);
1873 	bch2_fs_fatal_err_on(ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart), c,
1874 			     "reading stripe key: %s", bch2_err_str(ret));
1875 	if (ret) {
1876 		bch2_stripe_close(c, h->s);
1877 		return ret;
1878 	}
1879 
1880 	existing_v = &bkey_i_to_stripe(&h->s->existing_stripe.key)->v;
1881 
1882 	BUG_ON(existing_v->nr_redundant != h->s->nr_parity);
1883 	h->s->nr_data = existing_v->nr_blocks -
1884 		existing_v->nr_redundant;
1885 
1886 	ret = ec_stripe_buf_init(&h->s->existing_stripe, 0, h->blocksize);
1887 	if (ret) {
1888 		bch2_stripe_close(c, h->s);
1889 		return ret;
1890 	}
1891 
1892 	BUG_ON(h->s->existing_stripe.size != h->blocksize);
1893 	BUG_ON(h->s->existing_stripe.size != le16_to_cpu(existing_v->sectors));
1894 
1895 	/*
1896 	 * Free buckets we initially allocated - they might conflict with
1897 	 * blocks from the stripe we're reusing:
1898 	 */
1899 	for_each_set_bit(i, h->s->blocks_gotten, new_v->nr_blocks) {
1900 		bch2_open_bucket_put(c, c->open_buckets + h->s->blocks[i]);
1901 		h->s->blocks[i] = 0;
1902 	}
1903 	memset(h->s->blocks_gotten, 0, sizeof(h->s->blocks_gotten));
1904 	memset(h->s->blocks_allocated, 0, sizeof(h->s->blocks_allocated));
1905 
1906 	for (i = 0; i < existing_v->nr_blocks; i++) {
1907 		if (stripe_blockcount_get(existing_v, i)) {
1908 			__set_bit(i, h->s->blocks_gotten);
1909 			__set_bit(i, h->s->blocks_allocated);
1910 		}
1911 
1912 		ec_block_io(c, &h->s->existing_stripe, READ, i, &h->s->iodone);
1913 	}
1914 
1915 	bkey_copy(&h->s->new_stripe.key, &h->s->existing_stripe.key);
1916 	h->s->have_existing_stripe = true;
1917 
1918 	return 0;
1919 }
1920 
1921 static int __bch2_ec_stripe_head_reserve(struct btree_trans *trans, struct ec_stripe_head *h)
1922 {
1923 	struct bch_fs *c = trans->c;
1924 	struct btree_iter iter;
1925 	struct bkey_s_c k;
1926 	struct bpos min_pos = POS(0, 1);
1927 	struct bpos start_pos = bpos_max(min_pos, POS(0, c->ec_stripe_hint));
1928 	int ret;
1929 
1930 	if (!h->s->res.sectors) {
1931 		ret = bch2_disk_reservation_get(c, &h->s->res,
1932 					h->blocksize,
1933 					h->s->nr_parity,
1934 					BCH_DISK_RESERVATION_NOFAIL);
1935 		if (ret)
1936 			return ret;
1937 	}
1938 
1939 	for_each_btree_key_norestart(trans, iter, BTREE_ID_stripes, start_pos,
1940 			   BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
1941 		if (bkey_gt(k.k->p, POS(0, U32_MAX))) {
1942 			if (start_pos.offset) {
1943 				start_pos = min_pos;
1944 				bch2_btree_iter_set_pos(&iter, start_pos);
1945 				continue;
1946 			}
1947 
1948 			ret = -BCH_ERR_ENOSPC_stripe_create;
1949 			break;
1950 		}
1951 
1952 		if (bkey_deleted(k.k) &&
1953 		    bch2_try_open_stripe(c, h->s, k.k->p.offset))
1954 			break;
1955 	}
1956 
1957 	c->ec_stripe_hint = iter.pos.offset;
1958 
1959 	if (ret)
1960 		goto err;
1961 
1962 	ret = ec_stripe_mem_alloc(trans, &iter);
1963 	if (ret) {
1964 		bch2_stripe_close(c, h->s);
1965 		goto err;
1966 	}
1967 
1968 	h->s->new_stripe.key.k.p = iter.pos;
1969 out:
1970 	bch2_trans_iter_exit(trans, &iter);
1971 	return ret;
1972 err:
1973 	bch2_disk_reservation_put(c, &h->s->res);
1974 	goto out;
1975 }
1976 
1977 struct ec_stripe_head *bch2_ec_stripe_head_get(struct btree_trans *trans,
1978 					       unsigned target,
1979 					       unsigned algo,
1980 					       unsigned redundancy,
1981 					       enum bch_watermark watermark,
1982 					       struct closure *cl)
1983 {
1984 	struct bch_fs *c = trans->c;
1985 	struct ec_stripe_head *h;
1986 	bool waiting = false;
1987 	int ret;
1988 
1989 	h = __bch2_ec_stripe_head_get(trans, target, algo, redundancy, watermark);
1990 	if (IS_ERR_OR_NULL(h))
1991 		return h;
1992 
1993 	if (!h->s) {
1994 		ret = ec_new_stripe_alloc(c, h);
1995 		if (ret) {
1996 			bch_err(c, "failed to allocate new stripe");
1997 			goto err;
1998 		}
1999 	}
2000 
2001 	if (h->s->allocated)
2002 		goto allocated;
2003 
2004 	if (h->s->have_existing_stripe)
2005 		goto alloc_existing;
2006 
2007 	/* First, try to allocate a full stripe: */
2008 	ret =   new_stripe_alloc_buckets(trans, h, BCH_WATERMARK_stripe, NULL) ?:
2009 		__bch2_ec_stripe_head_reserve(trans, h);
2010 	if (!ret)
2011 		goto allocate_buf;
2012 	if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||
2013 	    bch2_err_matches(ret, ENOMEM))
2014 		goto err;
2015 
2016 	/*
2017 	 * Not enough buckets available for a full stripe: we must reuse an
2018 	 * existing stripe:
2019 	 */
2020 	while (1) {
2021 		ret = __bch2_ec_stripe_head_reuse(trans, h);
2022 		if (!ret)
2023 			break;
2024 		if (waiting || !cl || ret != -BCH_ERR_stripe_alloc_blocked)
2025 			goto err;
2026 
2027 		if (watermark == BCH_WATERMARK_copygc) {
2028 			ret =   new_stripe_alloc_buckets(trans, h, watermark, NULL) ?:
2029 				__bch2_ec_stripe_head_reserve(trans, h);
2030 			if (ret)
2031 				goto err;
2032 			goto allocate_buf;
2033 		}
2034 
2035 		/* XXX freelist_wait? */
2036 		closure_wait(&c->freelist_wait, cl);
2037 		waiting = true;
2038 	}
2039 
2040 	if (waiting)
2041 		closure_wake_up(&c->freelist_wait);
2042 alloc_existing:
2043 	/*
2044 	 * Retry allocating buckets, with the watermark for this
2045 	 * particular write:
2046 	 */
2047 	ret = new_stripe_alloc_buckets(trans, h, watermark, cl);
2048 	if (ret)
2049 		goto err;
2050 
2051 allocate_buf:
2052 	ret = ec_stripe_buf_init(&h->s->new_stripe, 0, h->blocksize);
2053 	if (ret)
2054 		goto err;
2055 
2056 	h->s->allocated = true;
2057 allocated:
2058 	BUG_ON(!h->s->idx);
2059 	BUG_ON(!h->s->new_stripe.data[0]);
2060 	BUG_ON(trans->restarted);
2061 	return h;
2062 err:
2063 	bch2_ec_stripe_head_put(c, h);
2064 	return ERR_PTR(ret);
2065 }
2066 
2067 static void __bch2_ec_stop(struct bch_fs *c, struct bch_dev *ca)
2068 {
2069 	struct ec_stripe_head *h;
2070 	struct open_bucket *ob;
2071 	unsigned i;
2072 
2073 	mutex_lock(&c->ec_stripe_head_lock);
2074 	list_for_each_entry(h, &c->ec_stripe_head_list, list) {
2075 		mutex_lock(&h->lock);
2076 		if (!h->s)
2077 			goto unlock;
2078 
2079 		if (!ca)
2080 			goto found;
2081 
2082 		for (i = 0; i < bkey_i_to_stripe(&h->s->new_stripe.key)->v.nr_blocks; i++) {
2083 			if (!h->s->blocks[i])
2084 				continue;
2085 
2086 			ob = c->open_buckets + h->s->blocks[i];
2087 			if (ob->dev == ca->dev_idx)
2088 				goto found;
2089 		}
2090 		goto unlock;
2091 found:
2092 		h->s->err = -BCH_ERR_erofs_no_writes;
2093 		ec_stripe_set_pending(c, h);
2094 unlock:
2095 		mutex_unlock(&h->lock);
2096 	}
2097 	mutex_unlock(&c->ec_stripe_head_lock);
2098 }
2099 
2100 void bch2_ec_stop_dev(struct bch_fs *c, struct bch_dev *ca)
2101 {
2102 	__bch2_ec_stop(c, ca);
2103 }
2104 
2105 void bch2_fs_ec_stop(struct bch_fs *c)
2106 {
2107 	__bch2_ec_stop(c, NULL);
2108 }
2109 
2110 static bool bch2_fs_ec_flush_done(struct bch_fs *c)
2111 {
2112 	bool ret;
2113 
2114 	mutex_lock(&c->ec_stripe_new_lock);
2115 	ret = list_empty(&c->ec_stripe_new_list);
2116 	mutex_unlock(&c->ec_stripe_new_lock);
2117 
2118 	return ret;
2119 }
2120 
2121 void bch2_fs_ec_flush(struct bch_fs *c)
2122 {
2123 	wait_event(c->ec_stripe_new_wait, bch2_fs_ec_flush_done(c));
2124 }
2125 
2126 int bch2_stripes_read(struct bch_fs *c)
2127 {
2128 	int ret = bch2_trans_run(c,
2129 		for_each_btree_key(trans, iter, BTREE_ID_stripes, POS_MIN,
2130 				   BTREE_ITER_PREFETCH, k, ({
2131 			if (k.k->type != KEY_TYPE_stripe)
2132 				continue;
2133 
2134 			ret = __ec_stripe_mem_alloc(c, k.k->p.offset, GFP_KERNEL);
2135 			if (ret)
2136 				break;
2137 
2138 			const struct bch_stripe *s = bkey_s_c_to_stripe(k).v;
2139 
2140 			struct stripe *m = genradix_ptr(&c->stripes, k.k->p.offset);
2141 			m->sectors	= le16_to_cpu(s->sectors);
2142 			m->algorithm	= s->algorithm;
2143 			m->nr_blocks	= s->nr_blocks;
2144 			m->nr_redundant	= s->nr_redundant;
2145 			m->blocks_nonempty = 0;
2146 
2147 			for (unsigned i = 0; i < s->nr_blocks; i++)
2148 				m->blocks_nonempty += !!stripe_blockcount_get(s, i);
2149 
2150 			bch2_stripes_heap_insert(c, m, k.k->p.offset);
2151 			0;
2152 		})));
2153 	bch_err_fn(c, ret);
2154 	return ret;
2155 }
2156 
2157 void bch2_stripes_heap_to_text(struct printbuf *out, struct bch_fs *c)
2158 {
2159 	ec_stripes_heap *h = &c->ec_stripes_heap;
2160 	struct stripe *m;
2161 	size_t i;
2162 
2163 	mutex_lock(&c->ec_stripes_heap_lock);
2164 	for (i = 0; i < min_t(size_t, h->used, 50); i++) {
2165 		m = genradix_ptr(&c->stripes, h->data[i].idx);
2166 
2167 		prt_printf(out, "%zu %u/%u+%u", h->data[i].idx,
2168 		       h->data[i].blocks_nonempty,
2169 		       m->nr_blocks - m->nr_redundant,
2170 		       m->nr_redundant);
2171 		if (bch2_stripe_is_open(c, h->data[i].idx))
2172 			prt_str(out, " open");
2173 		prt_newline(out);
2174 	}
2175 	mutex_unlock(&c->ec_stripes_heap_lock);
2176 }
2177 
2178 void bch2_new_stripes_to_text(struct printbuf *out, struct bch_fs *c)
2179 {
2180 	struct ec_stripe_head *h;
2181 	struct ec_stripe_new *s;
2182 
2183 	mutex_lock(&c->ec_stripe_head_lock);
2184 	list_for_each_entry(h, &c->ec_stripe_head_list, list) {
2185 		prt_printf(out, "target %u algo %u redundancy %u %s:\n",
2186 		       h->target, h->algo, h->redundancy,
2187 		       bch2_watermarks[h->watermark]);
2188 
2189 		if (h->s)
2190 			prt_printf(out, "\tidx %llu blocks %u+%u allocated %u\n",
2191 			       h->s->idx, h->s->nr_data, h->s->nr_parity,
2192 			       bitmap_weight(h->s->blocks_allocated,
2193 					     h->s->nr_data));
2194 	}
2195 	mutex_unlock(&c->ec_stripe_head_lock);
2196 
2197 	prt_printf(out, "in flight:\n");
2198 
2199 	mutex_lock(&c->ec_stripe_new_lock);
2200 	list_for_each_entry(s, &c->ec_stripe_new_list, list) {
2201 		prt_printf(out, "\tidx %llu blocks %u+%u ref %u %u %s\n",
2202 			   s->idx, s->nr_data, s->nr_parity,
2203 			   atomic_read(&s->ref[STRIPE_REF_io]),
2204 			   atomic_read(&s->ref[STRIPE_REF_stripe]),
2205 			   bch2_watermarks[s->h->watermark]);
2206 	}
2207 	mutex_unlock(&c->ec_stripe_new_lock);
2208 }
2209 
2210 void bch2_fs_ec_exit(struct bch_fs *c)
2211 {
2212 	struct ec_stripe_head *h;
2213 	unsigned i;
2214 
2215 	while (1) {
2216 		mutex_lock(&c->ec_stripe_head_lock);
2217 		h = list_first_entry_or_null(&c->ec_stripe_head_list,
2218 					     struct ec_stripe_head, list);
2219 		if (h)
2220 			list_del(&h->list);
2221 		mutex_unlock(&c->ec_stripe_head_lock);
2222 		if (!h)
2223 			break;
2224 
2225 		if (h->s) {
2226 			for (i = 0; i < bkey_i_to_stripe(&h->s->new_stripe.key)->v.nr_blocks; i++)
2227 				BUG_ON(h->s->blocks[i]);
2228 
2229 			kfree(h->s);
2230 		}
2231 		kfree(h);
2232 	}
2233 
2234 	BUG_ON(!list_empty(&c->ec_stripe_new_list));
2235 
2236 	free_heap(&c->ec_stripes_heap);
2237 	genradix_free(&c->stripes);
2238 	bioset_exit(&c->ec_bioset);
2239 }
2240 
2241 void bch2_fs_ec_init_early(struct bch_fs *c)
2242 {
2243 	spin_lock_init(&c->ec_stripes_new_lock);
2244 	mutex_init(&c->ec_stripes_heap_lock);
2245 
2246 	INIT_LIST_HEAD(&c->ec_stripe_head_list);
2247 	mutex_init(&c->ec_stripe_head_lock);
2248 
2249 	INIT_LIST_HEAD(&c->ec_stripe_new_list);
2250 	mutex_init(&c->ec_stripe_new_lock);
2251 	init_waitqueue_head(&c->ec_stripe_new_wait);
2252 
2253 	INIT_WORK(&c->ec_stripe_create_work, ec_stripe_create_work);
2254 	INIT_WORK(&c->ec_stripe_delete_work, ec_stripe_delete_work);
2255 }
2256 
2257 int bch2_fs_ec_init(struct bch_fs *c)
2258 {
2259 	return bioset_init(&c->ec_bioset, 1, offsetof(struct ec_bio, bio),
2260 			   BIOSET_NEED_BVECS);
2261 }
2262