xref: /linux/fs/bcachefs/ec.c (revision dbcedec3a31119d7594baacc743300d127c99c56)
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 *s = bkey_s_c_to_stripe(k).v;
135 	unsigned i, nr_data = s->nr_blocks - s->nr_redundant;
136 
137 	prt_printf(out, "algo %u sectors %u blocks %u:%u csum %u gran %u",
138 	       s->algorithm,
139 	       le16_to_cpu(s->sectors),
140 	       nr_data,
141 	       s->nr_redundant,
142 	       s->csum_type,
143 	       1U << s->csum_granularity_bits);
144 
145 	for (i = 0; i < s->nr_blocks; i++) {
146 		const struct bch_extent_ptr *ptr = s->ptrs + i;
147 		struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
148 		u32 offset;
149 		u64 b = sector_to_bucket_and_offset(ca, ptr->offset, &offset);
150 
151 		prt_printf(out, " %u:%llu:%u", ptr->dev, b, offset);
152 		if (i < nr_data)
153 			prt_printf(out, "#%u", stripe_blockcount_get(s, i));
154 		prt_printf(out, " gen %u", ptr->gen);
155 		if (ptr_stale(ca, ptr))
156 			prt_printf(out, " stale");
157 	}
158 }
159 
160 /* Triggers: */
161 
162 static int bch2_trans_mark_stripe_bucket(struct btree_trans *trans,
163 					 struct bkey_s_c_stripe s,
164 					 unsigned idx, bool deleting)
165 {
166 	struct bch_fs *c = trans->c;
167 	const struct bch_extent_ptr *ptr = &s.v->ptrs[idx];
168 	struct btree_iter iter;
169 	struct bkey_i_alloc_v4 *a;
170 	enum bch_data_type data_type = idx >= s.v->nr_blocks - s.v->nr_redundant
171 		? BCH_DATA_parity : 0;
172 	s64 sectors = data_type ? le16_to_cpu(s.v->sectors) : 0;
173 	int ret = 0;
174 
175 	if (deleting)
176 		sectors = -sectors;
177 
178 	a = bch2_trans_start_alloc_update(trans, &iter, PTR_BUCKET_POS(c, ptr));
179 	if (IS_ERR(a))
180 		return PTR_ERR(a);
181 
182 	ret = bch2_check_bucket_ref(trans, s.s_c, ptr, sectors, data_type,
183 				    a->v.gen, a->v.data_type,
184 				    a->v.dirty_sectors);
185 	if (ret)
186 		goto err;
187 
188 	if (!deleting) {
189 		if (bch2_trans_inconsistent_on(a->v.stripe ||
190 					       a->v.stripe_redundancy, trans,
191 				"bucket %llu:%llu gen %u data type %s dirty_sectors %u: multiple stripes using same bucket (%u, %llu)",
192 				iter.pos.inode, iter.pos.offset, a->v.gen,
193 				bch2_data_type_str(a->v.data_type),
194 				a->v.dirty_sectors,
195 				a->v.stripe, s.k->p.offset)) {
196 			ret = -EIO;
197 			goto err;
198 		}
199 
200 		if (bch2_trans_inconsistent_on(data_type && a->v.dirty_sectors, trans,
201 				"bucket %llu:%llu gen %u data type %s dirty_sectors %u: data already in stripe bucket %llu",
202 				iter.pos.inode, iter.pos.offset, a->v.gen,
203 				bch2_data_type_str(a->v.data_type),
204 				a->v.dirty_sectors,
205 				s.k->p.offset)) {
206 			ret = -EIO;
207 			goto err;
208 		}
209 
210 		a->v.stripe		= s.k->p.offset;
211 		a->v.stripe_redundancy	= s.v->nr_redundant;
212 		a->v.data_type		= BCH_DATA_stripe;
213 	} else {
214 		if (bch2_trans_inconsistent_on(a->v.stripe != s.k->p.offset ||
215 					       a->v.stripe_redundancy != s.v->nr_redundant, trans,
216 				"bucket %llu:%llu gen %u: not marked as stripe when deleting stripe %llu (got %u)",
217 				iter.pos.inode, iter.pos.offset, a->v.gen,
218 				s.k->p.offset, a->v.stripe)) {
219 			ret = -EIO;
220 			goto err;
221 		}
222 
223 		a->v.stripe		= 0;
224 		a->v.stripe_redundancy	= 0;
225 		a->v.data_type		= alloc_data_type(a->v, BCH_DATA_user);
226 	}
227 
228 	a->v.dirty_sectors += sectors;
229 	if (data_type)
230 		a->v.data_type = !deleting ? data_type : 0;
231 
232 	ret = bch2_trans_update(trans, &iter, &a->k_i, 0);
233 	if (ret)
234 		goto err;
235 err:
236 	bch2_trans_iter_exit(trans, &iter);
237 	return ret;
238 }
239 
240 static int mark_stripe_bucket(struct btree_trans *trans,
241 			      struct bkey_s_c k,
242 			      unsigned ptr_idx,
243 			      unsigned flags)
244 {
245 	struct bch_fs *c = trans->c;
246 	const struct bch_stripe *s = bkey_s_c_to_stripe(k).v;
247 	unsigned nr_data = s->nr_blocks - s->nr_redundant;
248 	bool parity = ptr_idx >= nr_data;
249 	enum bch_data_type data_type = parity ? BCH_DATA_parity : BCH_DATA_stripe;
250 	s64 sectors = parity ? le16_to_cpu(s->sectors) : 0;
251 	const struct bch_extent_ptr *ptr = s->ptrs + ptr_idx;
252 	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
253 	struct bucket old, new, *g;
254 	struct printbuf buf = PRINTBUF;
255 	int ret = 0;
256 
257 	BUG_ON(!(flags & BTREE_TRIGGER_GC));
258 
259 	/* * XXX doesn't handle deletion */
260 
261 	percpu_down_read(&c->mark_lock);
262 	g = PTR_GC_BUCKET(ca, ptr);
263 
264 	if (g->dirty_sectors ||
265 	    (g->stripe && g->stripe != k.k->p.offset)) {
266 		bch2_fs_inconsistent(c,
267 			      "bucket %u:%zu gen %u: multiple stripes using same bucket\n%s",
268 			      ptr->dev, PTR_BUCKET_NR(ca, ptr), g->gen,
269 			      (bch2_bkey_val_to_text(&buf, c, k), buf.buf));
270 		ret = -EINVAL;
271 		goto err;
272 	}
273 
274 	bucket_lock(g);
275 	old = *g;
276 
277 	ret = bch2_check_bucket_ref(trans, k, ptr, sectors, data_type,
278 				    g->gen, g->data_type,
279 				    g->dirty_sectors);
280 	if (ret)
281 		goto err;
282 
283 	g->data_type = data_type;
284 	g->dirty_sectors += sectors;
285 
286 	g->stripe		= k.k->p.offset;
287 	g->stripe_redundancy	= s->nr_redundant;
288 	new = *g;
289 err:
290 	bucket_unlock(g);
291 	if (!ret)
292 		bch2_dev_usage_update_m(c, ca, &old, &new);
293 	percpu_up_read(&c->mark_lock);
294 	printbuf_exit(&buf);
295 	return ret;
296 }
297 
298 int bch2_trigger_stripe(struct btree_trans *trans,
299 			enum btree_id btree_id, unsigned level,
300 			struct bkey_s_c old, struct bkey_s _new,
301 			unsigned flags)
302 {
303 	struct bkey_s_c new = _new.s_c;
304 	struct bch_fs *c = trans->c;
305 	u64 idx = new.k->p.offset;
306 	const struct bch_stripe *old_s = old.k->type == KEY_TYPE_stripe
307 		? bkey_s_c_to_stripe(old).v : NULL;
308 	const struct bch_stripe *new_s = new.k->type == KEY_TYPE_stripe
309 		? bkey_s_c_to_stripe(new).v : NULL;
310 
311 	if (flags & BTREE_TRIGGER_TRANSACTIONAL) {
312 		/*
313 		 * If the pointers aren't changing, we don't need to do anything:
314 		 */
315 		if (new_s && old_s &&
316 		    new_s->nr_blocks	== old_s->nr_blocks &&
317 		    new_s->nr_redundant	== old_s->nr_redundant &&
318 		    !memcmp(old_s->ptrs, new_s->ptrs,
319 			    new_s->nr_blocks * sizeof(struct bch_extent_ptr)))
320 			return 0;
321 
322 		BUG_ON(new_s && old_s &&
323 		       (new_s->nr_blocks	!= old_s->nr_blocks ||
324 			new_s->nr_redundant	!= old_s->nr_redundant));
325 
326 		if (new_s) {
327 			s64 sectors = le16_to_cpu(new_s->sectors);
328 
329 			struct bch_replicas_padded r;
330 			bch2_bkey_to_replicas(&r.e, new);
331 			int ret = bch2_update_replicas_list(trans, &r.e, sectors * new_s->nr_redundant);
332 			if (ret)
333 				return ret;
334 		}
335 
336 		if (old_s) {
337 			s64 sectors = -((s64) le16_to_cpu(old_s->sectors));
338 
339 			struct bch_replicas_padded r;
340 			bch2_bkey_to_replicas(&r.e, old);
341 			int ret = bch2_update_replicas_list(trans, &r.e, sectors * old_s->nr_redundant);
342 			if (ret)
343 				return ret;
344 		}
345 
346 		unsigned nr_blocks = new_s ? new_s->nr_blocks : old_s->nr_blocks;
347 		for (unsigned i = 0; i < nr_blocks; i++) {
348 			if (new_s && old_s &&
349 			    !memcmp(&new_s->ptrs[i],
350 				    &old_s->ptrs[i],
351 				    sizeof(new_s->ptrs[i])))
352 				continue;
353 
354 			if (new_s) {
355 				int ret = bch2_trans_mark_stripe_bucket(trans,
356 						bkey_s_c_to_stripe(new), i, false);
357 				if (ret)
358 					return ret;
359 			}
360 
361 			if (old_s) {
362 				int ret = bch2_trans_mark_stripe_bucket(trans,
363 						bkey_s_c_to_stripe(old), i, true);
364 				if (ret)
365 					return ret;
366 			}
367 		}
368 	}
369 
370 	if (flags & BTREE_TRIGGER_ATOMIC) {
371 		struct stripe *m = genradix_ptr(&c->stripes, idx);
372 
373 		if (!m) {
374 			struct printbuf buf1 = PRINTBUF;
375 			struct printbuf buf2 = PRINTBUF;
376 
377 			bch2_bkey_val_to_text(&buf1, c, old);
378 			bch2_bkey_val_to_text(&buf2, c, new);
379 			bch_err_ratelimited(c, "error marking nonexistent stripe %llu while marking\n"
380 					    "old %s\n"
381 					    "new %s", idx, buf1.buf, buf2.buf);
382 			printbuf_exit(&buf2);
383 			printbuf_exit(&buf1);
384 			bch2_inconsistent_error(c);
385 			return -1;
386 		}
387 
388 		if (!new_s) {
389 			bch2_stripes_heap_del(c, m, idx);
390 
391 			memset(m, 0, sizeof(*m));
392 		} else {
393 			m->sectors	= le16_to_cpu(new_s->sectors);
394 			m->algorithm	= new_s->algorithm;
395 			m->nr_blocks	= new_s->nr_blocks;
396 			m->nr_redundant	= new_s->nr_redundant;
397 			m->blocks_nonempty = 0;
398 
399 			for (unsigned i = 0; i < new_s->nr_blocks; i++)
400 				m->blocks_nonempty += !!stripe_blockcount_get(new_s, i);
401 
402 			if (!old_s)
403 				bch2_stripes_heap_insert(c, m, idx);
404 			else
405 				bch2_stripes_heap_update(c, m, idx);
406 		}
407 	}
408 
409 	if (flags & BTREE_TRIGGER_GC) {
410 		struct gc_stripe *m =
411 			genradix_ptr_alloc(&c->gc_stripes, idx, GFP_KERNEL);
412 
413 		if (!m) {
414 			bch_err(c, "error allocating memory for gc_stripes, idx %llu",
415 				idx);
416 			return -BCH_ERR_ENOMEM_mark_stripe;
417 		}
418 		/*
419 		 * This will be wrong when we bring back runtime gc: we should
420 		 * be unmarking the old key and then marking the new key
421 		 */
422 		m->alive	= true;
423 		m->sectors	= le16_to_cpu(new_s->sectors);
424 		m->nr_blocks	= new_s->nr_blocks;
425 		m->nr_redundant	= new_s->nr_redundant;
426 
427 		for (unsigned i = 0; i < new_s->nr_blocks; i++)
428 			m->ptrs[i] = new_s->ptrs[i];
429 
430 		bch2_bkey_to_replicas(&m->r.e, new);
431 
432 		/*
433 		 * gc recalculates this field from stripe ptr
434 		 * references:
435 		 */
436 		memset(m->block_sectors, 0, sizeof(m->block_sectors));
437 
438 		for (unsigned i = 0; i < new_s->nr_blocks; i++) {
439 			int ret = mark_stripe_bucket(trans, new, i, flags);
440 			if (ret)
441 				return ret;
442 		}
443 
444 		int ret = bch2_update_replicas(c, new, &m->r.e,
445 				      ((s64) m->sectors * m->nr_redundant),
446 				      0, true);
447 		if (ret) {
448 			struct printbuf buf = PRINTBUF;
449 
450 			bch2_bkey_val_to_text(&buf, c, new);
451 			bch2_fs_fatal_error(c, ": no replicas entry for %s", buf.buf);
452 			printbuf_exit(&buf);
453 			return ret;
454 		}
455 	}
456 
457 	return 0;
458 }
459 
460 /* returns blocknr in stripe that we matched: */
461 static const struct bch_extent_ptr *bkey_matches_stripe(struct bch_stripe *s,
462 						struct bkey_s_c k, unsigned *block)
463 {
464 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
465 	unsigned i, nr_data = s->nr_blocks - s->nr_redundant;
466 
467 	bkey_for_each_ptr(ptrs, ptr)
468 		for (i = 0; i < nr_data; i++)
469 			if (__bch2_ptr_matches_stripe(&s->ptrs[i], ptr,
470 						      le16_to_cpu(s->sectors))) {
471 				*block = i;
472 				return ptr;
473 			}
474 
475 	return NULL;
476 }
477 
478 static bool extent_has_stripe_ptr(struct bkey_s_c k, u64 idx)
479 {
480 	switch (k.k->type) {
481 	case KEY_TYPE_extent: {
482 		struct bkey_s_c_extent e = bkey_s_c_to_extent(k);
483 		const union bch_extent_entry *entry;
484 
485 		extent_for_each_entry(e, entry)
486 			if (extent_entry_type(entry) ==
487 			    BCH_EXTENT_ENTRY_stripe_ptr &&
488 			    entry->stripe_ptr.idx == idx)
489 				return true;
490 
491 		break;
492 	}
493 	}
494 
495 	return false;
496 }
497 
498 /* Stripe bufs: */
499 
500 static void ec_stripe_buf_exit(struct ec_stripe_buf *buf)
501 {
502 	if (buf->key.k.type == KEY_TYPE_stripe) {
503 		struct bkey_i_stripe *s = bkey_i_to_stripe(&buf->key);
504 		unsigned i;
505 
506 		for (i = 0; i < s->v.nr_blocks; i++) {
507 			kvfree(buf->data[i]);
508 			buf->data[i] = NULL;
509 		}
510 	}
511 }
512 
513 /* XXX: this is a non-mempoolified memory allocation: */
514 static int ec_stripe_buf_init(struct ec_stripe_buf *buf,
515 			      unsigned offset, unsigned size)
516 {
517 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
518 	unsigned csum_granularity = 1U << v->csum_granularity_bits;
519 	unsigned end = offset + size;
520 	unsigned i;
521 
522 	BUG_ON(end > le16_to_cpu(v->sectors));
523 
524 	offset	= round_down(offset, csum_granularity);
525 	end	= min_t(unsigned, le16_to_cpu(v->sectors),
526 			round_up(end, csum_granularity));
527 
528 	buf->offset	= offset;
529 	buf->size	= end - offset;
530 
531 	memset(buf->valid, 0xFF, sizeof(buf->valid));
532 
533 	for (i = 0; i < v->nr_blocks; i++) {
534 		buf->data[i] = kvmalloc(buf->size << 9, GFP_KERNEL);
535 		if (!buf->data[i])
536 			goto err;
537 	}
538 
539 	return 0;
540 err:
541 	ec_stripe_buf_exit(buf);
542 	return -BCH_ERR_ENOMEM_stripe_buf;
543 }
544 
545 /* Checksumming: */
546 
547 static struct bch_csum ec_block_checksum(struct ec_stripe_buf *buf,
548 					 unsigned block, unsigned offset)
549 {
550 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
551 	unsigned csum_granularity = 1 << v->csum_granularity_bits;
552 	unsigned end = buf->offset + buf->size;
553 	unsigned len = min(csum_granularity, end - offset);
554 
555 	BUG_ON(offset >= end);
556 	BUG_ON(offset <  buf->offset);
557 	BUG_ON(offset & (csum_granularity - 1));
558 	BUG_ON(offset + len != le16_to_cpu(v->sectors) &&
559 	       (len & (csum_granularity - 1)));
560 
561 	return bch2_checksum(NULL, v->csum_type,
562 			     null_nonce(),
563 			     buf->data[block] + ((offset - buf->offset) << 9),
564 			     len << 9);
565 }
566 
567 static void ec_generate_checksums(struct ec_stripe_buf *buf)
568 {
569 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
570 	unsigned i, j, csums_per_device = stripe_csums_per_device(v);
571 
572 	if (!v->csum_type)
573 		return;
574 
575 	BUG_ON(buf->offset);
576 	BUG_ON(buf->size != le16_to_cpu(v->sectors));
577 
578 	for (i = 0; i < v->nr_blocks; i++)
579 		for (j = 0; j < csums_per_device; j++)
580 			stripe_csum_set(v, i, j,
581 				ec_block_checksum(buf, i, j << v->csum_granularity_bits));
582 }
583 
584 static void ec_validate_checksums(struct bch_fs *c, struct ec_stripe_buf *buf)
585 {
586 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
587 	unsigned csum_granularity = 1 << v->csum_granularity_bits;
588 	unsigned i;
589 
590 	if (!v->csum_type)
591 		return;
592 
593 	for (i = 0; i < v->nr_blocks; i++) {
594 		unsigned offset = buf->offset;
595 		unsigned end = buf->offset + buf->size;
596 
597 		if (!test_bit(i, buf->valid))
598 			continue;
599 
600 		while (offset < end) {
601 			unsigned j = offset >> v->csum_granularity_bits;
602 			unsigned len = min(csum_granularity, end - offset);
603 			struct bch_csum want = stripe_csum_get(v, i, j);
604 			struct bch_csum got = ec_block_checksum(buf, i, offset);
605 
606 			if (bch2_crc_cmp(want, got)) {
607 				struct printbuf err = PRINTBUF;
608 				struct bch_dev *ca = bch_dev_bkey_exists(c, v->ptrs[i].dev);
609 
610 				prt_printf(&err, "stripe checksum error: expected %0llx:%0llx got %0llx:%0llx (type %s)\n",
611 					   want.hi, want.lo,
612 					   got.hi, got.lo,
613 					   bch2_csum_types[v->csum_type]);
614 				prt_printf(&err, "  for %ps at %u of\n  ", (void *) _RET_IP_, i);
615 				bch2_bkey_val_to_text(&err, c, bkey_i_to_s_c(&buf->key));
616 				bch_err_ratelimited(ca, "%s", err.buf);
617 				printbuf_exit(&err);
618 
619 				clear_bit(i, buf->valid);
620 
621 				bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
622 				break;
623 			}
624 
625 			offset += len;
626 		}
627 	}
628 }
629 
630 /* Erasure coding: */
631 
632 static void ec_generate_ec(struct ec_stripe_buf *buf)
633 {
634 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
635 	unsigned nr_data = v->nr_blocks - v->nr_redundant;
636 	unsigned bytes = le16_to_cpu(v->sectors) << 9;
637 
638 	raid_gen(nr_data, v->nr_redundant, bytes, buf->data);
639 }
640 
641 static unsigned ec_nr_failed(struct ec_stripe_buf *buf)
642 {
643 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
644 
645 	return v->nr_blocks - bitmap_weight(buf->valid, v->nr_blocks);
646 }
647 
648 static int ec_do_recov(struct bch_fs *c, struct ec_stripe_buf *buf)
649 {
650 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
651 	unsigned i, failed[BCH_BKEY_PTRS_MAX], nr_failed = 0;
652 	unsigned nr_data = v->nr_blocks - v->nr_redundant;
653 	unsigned bytes = buf->size << 9;
654 
655 	if (ec_nr_failed(buf) > v->nr_redundant) {
656 		bch_err_ratelimited(c,
657 			"error doing reconstruct read: unable to read enough blocks");
658 		return -1;
659 	}
660 
661 	for (i = 0; i < nr_data; i++)
662 		if (!test_bit(i, buf->valid))
663 			failed[nr_failed++] = i;
664 
665 	raid_rec(nr_failed, failed, nr_data, v->nr_redundant, bytes, buf->data);
666 	return 0;
667 }
668 
669 /* IO: */
670 
671 static void ec_block_endio(struct bio *bio)
672 {
673 	struct ec_bio *ec_bio = container_of(bio, struct ec_bio, bio);
674 	struct bch_stripe *v = &bkey_i_to_stripe(&ec_bio->buf->key)->v;
675 	struct bch_extent_ptr *ptr = &v->ptrs[ec_bio->idx];
676 	struct bch_dev *ca = ec_bio->ca;
677 	struct closure *cl = bio->bi_private;
678 
679 	if (bch2_dev_io_err_on(bio->bi_status, ca,
680 			       bio_data_dir(bio)
681 			       ? BCH_MEMBER_ERROR_write
682 			       : BCH_MEMBER_ERROR_read,
683 			       "erasure coding %s error: %s",
684 			       bio_data_dir(bio) ? "write" : "read",
685 			       bch2_blk_status_to_str(bio->bi_status)))
686 		clear_bit(ec_bio->idx, ec_bio->buf->valid);
687 
688 	if (ptr_stale(ca, ptr)) {
689 		bch_err_ratelimited(ca->fs,
690 				    "error %s stripe: stale pointer after io",
691 				    bio_data_dir(bio) == READ ? "reading from" : "writing to");
692 		clear_bit(ec_bio->idx, ec_bio->buf->valid);
693 	}
694 
695 	bio_put(&ec_bio->bio);
696 	percpu_ref_put(&ca->io_ref);
697 	closure_put(cl);
698 }
699 
700 static void ec_block_io(struct bch_fs *c, struct ec_stripe_buf *buf,
701 			blk_opf_t opf, unsigned idx, struct closure *cl)
702 {
703 	struct bch_stripe *v = &bkey_i_to_stripe(&buf->key)->v;
704 	unsigned offset = 0, bytes = buf->size << 9;
705 	struct bch_extent_ptr *ptr = &v->ptrs[idx];
706 	struct bch_dev *ca = bch_dev_bkey_exists(c, ptr->dev);
707 	enum bch_data_type data_type = idx < v->nr_blocks - v->nr_redundant
708 		? BCH_DATA_user
709 		: BCH_DATA_parity;
710 	int rw = op_is_write(opf);
711 
712 	if (ptr_stale(ca, ptr)) {
713 		bch_err_ratelimited(c,
714 				    "error %s stripe: stale pointer",
715 				    rw == READ ? "reading from" : "writing to");
716 		clear_bit(idx, buf->valid);
717 		return;
718 	}
719 
720 	if (!bch2_dev_get_ioref(ca, rw)) {
721 		clear_bit(idx, buf->valid);
722 		return;
723 	}
724 
725 	this_cpu_add(ca->io_done->sectors[rw][data_type], buf->size);
726 
727 	while (offset < bytes) {
728 		unsigned nr_iovecs = min_t(size_t, BIO_MAX_VECS,
729 					   DIV_ROUND_UP(bytes, PAGE_SIZE));
730 		unsigned b = min_t(size_t, bytes - offset,
731 				   nr_iovecs << PAGE_SHIFT);
732 		struct ec_bio *ec_bio;
733 
734 		ec_bio = container_of(bio_alloc_bioset(ca->disk_sb.bdev,
735 						       nr_iovecs,
736 						       opf,
737 						       GFP_KERNEL,
738 						       &c->ec_bioset),
739 				      struct ec_bio, bio);
740 
741 		ec_bio->ca			= ca;
742 		ec_bio->buf			= buf;
743 		ec_bio->idx			= idx;
744 
745 		ec_bio->bio.bi_iter.bi_sector	= ptr->offset + buf->offset + (offset >> 9);
746 		ec_bio->bio.bi_end_io		= ec_block_endio;
747 		ec_bio->bio.bi_private		= cl;
748 
749 		bch2_bio_map(&ec_bio->bio, buf->data[idx] + offset, b);
750 
751 		closure_get(cl);
752 		percpu_ref_get(&ca->io_ref);
753 
754 		submit_bio(&ec_bio->bio);
755 
756 		offset += b;
757 	}
758 
759 	percpu_ref_put(&ca->io_ref);
760 }
761 
762 static int get_stripe_key_trans(struct btree_trans *trans, u64 idx,
763 				struct ec_stripe_buf *stripe)
764 {
765 	struct btree_iter iter;
766 	struct bkey_s_c k;
767 	int ret;
768 
769 	k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_stripes,
770 			       POS(0, idx), BTREE_ITER_SLOTS);
771 	ret = bkey_err(k);
772 	if (ret)
773 		goto err;
774 	if (k.k->type != KEY_TYPE_stripe) {
775 		ret = -ENOENT;
776 		goto err;
777 	}
778 	bkey_reassemble(&stripe->key, k);
779 err:
780 	bch2_trans_iter_exit(trans, &iter);
781 	return ret;
782 }
783 
784 /* recovery read path: */
785 int bch2_ec_read_extent(struct btree_trans *trans, struct bch_read_bio *rbio)
786 {
787 	struct bch_fs *c = trans->c;
788 	struct ec_stripe_buf *buf;
789 	struct closure cl;
790 	struct bch_stripe *v;
791 	unsigned i, offset;
792 	int ret = 0;
793 
794 	closure_init_stack(&cl);
795 
796 	BUG_ON(!rbio->pick.has_ec);
797 
798 	buf = kzalloc(sizeof(*buf), GFP_NOFS);
799 	if (!buf)
800 		return -BCH_ERR_ENOMEM_ec_read_extent;
801 
802 	ret = lockrestart_do(trans, get_stripe_key_trans(trans, rbio->pick.ec.idx, buf));
803 	if (ret) {
804 		bch_err_ratelimited(c,
805 			"error doing reconstruct read: error %i looking up stripe", ret);
806 		kfree(buf);
807 		return -EIO;
808 	}
809 
810 	v = &bkey_i_to_stripe(&buf->key)->v;
811 
812 	if (!bch2_ptr_matches_stripe(v, rbio->pick)) {
813 		bch_err_ratelimited(c,
814 			"error doing reconstruct read: pointer doesn't match stripe");
815 		ret = -EIO;
816 		goto err;
817 	}
818 
819 	offset = rbio->bio.bi_iter.bi_sector - v->ptrs[rbio->pick.ec.block].offset;
820 	if (offset + bio_sectors(&rbio->bio) > le16_to_cpu(v->sectors)) {
821 		bch_err_ratelimited(c,
822 			"error doing reconstruct read: read is bigger than stripe");
823 		ret = -EIO;
824 		goto err;
825 	}
826 
827 	ret = ec_stripe_buf_init(buf, offset, bio_sectors(&rbio->bio));
828 	if (ret)
829 		goto err;
830 
831 	for (i = 0; i < v->nr_blocks; i++)
832 		ec_block_io(c, buf, REQ_OP_READ, i, &cl);
833 
834 	closure_sync(&cl);
835 
836 	if (ec_nr_failed(buf) > v->nr_redundant) {
837 		bch_err_ratelimited(c,
838 			"error doing reconstruct read: unable to read enough blocks");
839 		ret = -EIO;
840 		goto err;
841 	}
842 
843 	ec_validate_checksums(c, buf);
844 
845 	ret = ec_do_recov(c, buf);
846 	if (ret)
847 		goto err;
848 
849 	memcpy_to_bio(&rbio->bio, rbio->bio.bi_iter,
850 		      buf->data[rbio->pick.ec.block] + ((offset - buf->offset) << 9));
851 err:
852 	ec_stripe_buf_exit(buf);
853 	kfree(buf);
854 	return ret;
855 }
856 
857 /* stripe bucket accounting: */
858 
859 static int __ec_stripe_mem_alloc(struct bch_fs *c, size_t idx, gfp_t gfp)
860 {
861 	ec_stripes_heap n, *h = &c->ec_stripes_heap;
862 
863 	if (idx >= h->size) {
864 		if (!init_heap(&n, max(1024UL, roundup_pow_of_two(idx + 1)), gfp))
865 			return -BCH_ERR_ENOMEM_ec_stripe_mem_alloc;
866 
867 		mutex_lock(&c->ec_stripes_heap_lock);
868 		if (n.size > h->size) {
869 			memcpy(n.data, h->data, h->used * sizeof(h->data[0]));
870 			n.used = h->used;
871 			swap(*h, n);
872 		}
873 		mutex_unlock(&c->ec_stripes_heap_lock);
874 
875 		free_heap(&n);
876 	}
877 
878 	if (!genradix_ptr_alloc(&c->stripes, idx, gfp))
879 		return -BCH_ERR_ENOMEM_ec_stripe_mem_alloc;
880 
881 	if (c->gc_pos.phase != GC_PHASE_NOT_RUNNING &&
882 	    !genradix_ptr_alloc(&c->gc_stripes, idx, gfp))
883 		return -BCH_ERR_ENOMEM_ec_stripe_mem_alloc;
884 
885 	return 0;
886 }
887 
888 static int ec_stripe_mem_alloc(struct btree_trans *trans,
889 			       struct btree_iter *iter)
890 {
891 	return allocate_dropping_locks_errcode(trans,
892 			__ec_stripe_mem_alloc(trans->c, iter->pos.offset, _gfp));
893 }
894 
895 /*
896  * Hash table of open stripes:
897  * Stripes that are being created or modified are kept in a hash table, so that
898  * stripe deletion can skip them.
899  */
900 
901 static bool __bch2_stripe_is_open(struct bch_fs *c, u64 idx)
902 {
903 	unsigned hash = hash_64(idx, ilog2(ARRAY_SIZE(c->ec_stripes_new)));
904 	struct ec_stripe_new *s;
905 
906 	hlist_for_each_entry(s, &c->ec_stripes_new[hash], hash)
907 		if (s->idx == idx)
908 			return true;
909 	return false;
910 }
911 
912 static bool bch2_stripe_is_open(struct bch_fs *c, u64 idx)
913 {
914 	bool ret = false;
915 
916 	spin_lock(&c->ec_stripes_new_lock);
917 	ret = __bch2_stripe_is_open(c, idx);
918 	spin_unlock(&c->ec_stripes_new_lock);
919 
920 	return ret;
921 }
922 
923 static bool bch2_try_open_stripe(struct bch_fs *c,
924 				 struct ec_stripe_new *s,
925 				 u64 idx)
926 {
927 	bool ret;
928 
929 	spin_lock(&c->ec_stripes_new_lock);
930 	ret = !__bch2_stripe_is_open(c, idx);
931 	if (ret) {
932 		unsigned hash = hash_64(idx, ilog2(ARRAY_SIZE(c->ec_stripes_new)));
933 
934 		s->idx = idx;
935 		hlist_add_head(&s->hash, &c->ec_stripes_new[hash]);
936 	}
937 	spin_unlock(&c->ec_stripes_new_lock);
938 
939 	return ret;
940 }
941 
942 static void bch2_stripe_close(struct bch_fs *c, struct ec_stripe_new *s)
943 {
944 	BUG_ON(!s->idx);
945 
946 	spin_lock(&c->ec_stripes_new_lock);
947 	hlist_del_init(&s->hash);
948 	spin_unlock(&c->ec_stripes_new_lock);
949 
950 	s->idx = 0;
951 }
952 
953 /* Heap of all existing stripes, ordered by blocks_nonempty */
954 
955 static u64 stripe_idx_to_delete(struct bch_fs *c)
956 {
957 	ec_stripes_heap *h = &c->ec_stripes_heap;
958 
959 	lockdep_assert_held(&c->ec_stripes_heap_lock);
960 
961 	if (h->used &&
962 	    h->data[0].blocks_nonempty == 0 &&
963 	    !bch2_stripe_is_open(c, h->data[0].idx))
964 		return h->data[0].idx;
965 
966 	return 0;
967 }
968 
969 static inline int ec_stripes_heap_cmp(ec_stripes_heap *h,
970 				      struct ec_stripe_heap_entry l,
971 				      struct ec_stripe_heap_entry r)
972 {
973 	return ((l.blocks_nonempty > r.blocks_nonempty) -
974 		(l.blocks_nonempty < r.blocks_nonempty));
975 }
976 
977 static inline void ec_stripes_heap_set_backpointer(ec_stripes_heap *h,
978 						   size_t i)
979 {
980 	struct bch_fs *c = container_of(h, struct bch_fs, ec_stripes_heap);
981 
982 	genradix_ptr(&c->stripes, h->data[i].idx)->heap_idx = i;
983 }
984 
985 static void heap_verify_backpointer(struct bch_fs *c, size_t idx)
986 {
987 	ec_stripes_heap *h = &c->ec_stripes_heap;
988 	struct stripe *m = genradix_ptr(&c->stripes, idx);
989 
990 	BUG_ON(m->heap_idx >= h->used);
991 	BUG_ON(h->data[m->heap_idx].idx != idx);
992 }
993 
994 void bch2_stripes_heap_del(struct bch_fs *c,
995 			   struct stripe *m, size_t idx)
996 {
997 	mutex_lock(&c->ec_stripes_heap_lock);
998 	heap_verify_backpointer(c, idx);
999 
1000 	heap_del(&c->ec_stripes_heap, m->heap_idx,
1001 		 ec_stripes_heap_cmp,
1002 		 ec_stripes_heap_set_backpointer);
1003 	mutex_unlock(&c->ec_stripes_heap_lock);
1004 }
1005 
1006 void bch2_stripes_heap_insert(struct bch_fs *c,
1007 			      struct stripe *m, size_t idx)
1008 {
1009 	mutex_lock(&c->ec_stripes_heap_lock);
1010 	BUG_ON(heap_full(&c->ec_stripes_heap));
1011 
1012 	heap_add(&c->ec_stripes_heap, ((struct ec_stripe_heap_entry) {
1013 			.idx = idx,
1014 			.blocks_nonempty = m->blocks_nonempty,
1015 		}),
1016 		 ec_stripes_heap_cmp,
1017 		 ec_stripes_heap_set_backpointer);
1018 
1019 	heap_verify_backpointer(c, idx);
1020 	mutex_unlock(&c->ec_stripes_heap_lock);
1021 }
1022 
1023 void bch2_stripes_heap_update(struct bch_fs *c,
1024 			      struct stripe *m, size_t idx)
1025 {
1026 	ec_stripes_heap *h = &c->ec_stripes_heap;
1027 	bool do_deletes;
1028 	size_t i;
1029 
1030 	mutex_lock(&c->ec_stripes_heap_lock);
1031 	heap_verify_backpointer(c, idx);
1032 
1033 	h->data[m->heap_idx].blocks_nonempty = m->blocks_nonempty;
1034 
1035 	i = m->heap_idx;
1036 	heap_sift_up(h,	  i, ec_stripes_heap_cmp,
1037 		     ec_stripes_heap_set_backpointer);
1038 	heap_sift_down(h, i, ec_stripes_heap_cmp,
1039 		       ec_stripes_heap_set_backpointer);
1040 
1041 	heap_verify_backpointer(c, idx);
1042 
1043 	do_deletes = stripe_idx_to_delete(c) != 0;
1044 	mutex_unlock(&c->ec_stripes_heap_lock);
1045 
1046 	if (do_deletes)
1047 		bch2_do_stripe_deletes(c);
1048 }
1049 
1050 /* stripe deletion */
1051 
1052 static int ec_stripe_delete(struct btree_trans *trans, u64 idx)
1053 {
1054 	struct bch_fs *c = trans->c;
1055 	struct btree_iter iter;
1056 	struct bkey_s_c k;
1057 	struct bkey_s_c_stripe s;
1058 	int ret;
1059 
1060 	k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_stripes, POS(0, idx),
1061 			       BTREE_ITER_INTENT);
1062 	ret = bkey_err(k);
1063 	if (ret)
1064 		goto err;
1065 
1066 	if (k.k->type != KEY_TYPE_stripe) {
1067 		bch2_fs_inconsistent(c, "attempting to delete nonexistent stripe %llu", idx);
1068 		ret = -EINVAL;
1069 		goto err;
1070 	}
1071 
1072 	s = bkey_s_c_to_stripe(k);
1073 	for (unsigned i = 0; i < s.v->nr_blocks; i++)
1074 		if (stripe_blockcount_get(s.v, i)) {
1075 			struct printbuf buf = PRINTBUF;
1076 
1077 			bch2_bkey_val_to_text(&buf, c, k);
1078 			bch2_fs_inconsistent(c, "attempting to delete nonempty stripe %s", buf.buf);
1079 			printbuf_exit(&buf);
1080 			ret = -EINVAL;
1081 			goto err;
1082 		}
1083 
1084 	ret = bch2_btree_delete_at(trans, &iter, 0);
1085 err:
1086 	bch2_trans_iter_exit(trans, &iter);
1087 	return ret;
1088 }
1089 
1090 static void ec_stripe_delete_work(struct work_struct *work)
1091 {
1092 	struct bch_fs *c =
1093 		container_of(work, struct bch_fs, ec_stripe_delete_work);
1094 
1095 	while (1) {
1096 		mutex_lock(&c->ec_stripes_heap_lock);
1097 		u64 idx = stripe_idx_to_delete(c);
1098 		mutex_unlock(&c->ec_stripes_heap_lock);
1099 
1100 		if (!idx)
1101 			break;
1102 
1103 		int ret = bch2_trans_do(c, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
1104 					ec_stripe_delete(trans, idx));
1105 		bch_err_fn(c, ret);
1106 		if (ret)
1107 			break;
1108 	}
1109 
1110 	bch2_write_ref_put(c, BCH_WRITE_REF_stripe_delete);
1111 }
1112 
1113 void bch2_do_stripe_deletes(struct bch_fs *c)
1114 {
1115 	if (bch2_write_ref_tryget(c, BCH_WRITE_REF_stripe_delete) &&
1116 	    !queue_work(c->write_ref_wq, &c->ec_stripe_delete_work))
1117 		bch2_write_ref_put(c, BCH_WRITE_REF_stripe_delete);
1118 }
1119 
1120 /* stripe creation: */
1121 
1122 static int ec_stripe_key_update(struct btree_trans *trans,
1123 				struct bkey_i_stripe *new,
1124 				bool create)
1125 {
1126 	struct bch_fs *c = trans->c;
1127 	struct btree_iter iter;
1128 	struct bkey_s_c k;
1129 	int ret;
1130 
1131 	k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_stripes,
1132 			       new->k.p, BTREE_ITER_INTENT);
1133 	ret = bkey_err(k);
1134 	if (ret)
1135 		goto err;
1136 
1137 	if (k.k->type != (create ? KEY_TYPE_deleted : KEY_TYPE_stripe)) {
1138 		bch2_fs_inconsistent(c, "error %s stripe: got existing key type %s",
1139 				     create ? "creating" : "updating",
1140 				     bch2_bkey_types[k.k->type]);
1141 		ret = -EINVAL;
1142 		goto err;
1143 	}
1144 
1145 	if (k.k->type == KEY_TYPE_stripe) {
1146 		const struct bch_stripe *old = bkey_s_c_to_stripe(k).v;
1147 		unsigned i;
1148 
1149 		if (old->nr_blocks != new->v.nr_blocks) {
1150 			bch_err(c, "error updating stripe: nr_blocks does not match");
1151 			ret = -EINVAL;
1152 			goto err;
1153 		}
1154 
1155 		for (i = 0; i < new->v.nr_blocks; i++) {
1156 			unsigned v = stripe_blockcount_get(old, i);
1157 
1158 			BUG_ON(v &&
1159 			       (old->ptrs[i].dev != new->v.ptrs[i].dev ||
1160 				old->ptrs[i].gen != new->v.ptrs[i].gen ||
1161 				old->ptrs[i].offset != new->v.ptrs[i].offset));
1162 
1163 			stripe_blockcount_set(&new->v, i, v);
1164 		}
1165 	}
1166 
1167 	ret = bch2_trans_update(trans, &iter, &new->k_i, 0);
1168 err:
1169 	bch2_trans_iter_exit(trans, &iter);
1170 	return ret;
1171 }
1172 
1173 static int ec_stripe_update_extent(struct btree_trans *trans,
1174 				   struct bpos bucket, u8 gen,
1175 				   struct ec_stripe_buf *s,
1176 				   struct bpos *bp_pos)
1177 {
1178 	struct bch_stripe *v = &bkey_i_to_stripe(&s->key)->v;
1179 	struct bch_fs *c = trans->c;
1180 	struct bch_backpointer bp;
1181 	struct btree_iter iter;
1182 	struct bkey_s_c k;
1183 	const struct bch_extent_ptr *ptr_c;
1184 	struct bch_extent_ptr *ptr, *ec_ptr = NULL;
1185 	struct bch_extent_stripe_ptr stripe_ptr;
1186 	struct bkey_i *n;
1187 	int ret, dev, block;
1188 
1189 	ret = bch2_get_next_backpointer(trans, bucket, gen,
1190 				bp_pos, &bp, BTREE_ITER_CACHED);
1191 	if (ret)
1192 		return ret;
1193 	if (bpos_eq(*bp_pos, SPOS_MAX))
1194 		return 0;
1195 
1196 	if (bp.level) {
1197 		struct printbuf buf = PRINTBUF;
1198 		struct btree_iter node_iter;
1199 		struct btree *b;
1200 
1201 		b = bch2_backpointer_get_node(trans, &node_iter, *bp_pos, bp);
1202 		bch2_trans_iter_exit(trans, &node_iter);
1203 
1204 		if (!b)
1205 			return 0;
1206 
1207 		prt_printf(&buf, "found btree node in erasure coded bucket: b=%px\n", b);
1208 		bch2_backpointer_to_text(&buf, &bp);
1209 
1210 		bch2_fs_inconsistent(c, "%s", buf.buf);
1211 		printbuf_exit(&buf);
1212 		return -EIO;
1213 	}
1214 
1215 	k = bch2_backpointer_get_key(trans, &iter, *bp_pos, bp, BTREE_ITER_INTENT);
1216 	ret = bkey_err(k);
1217 	if (ret)
1218 		return ret;
1219 	if (!k.k) {
1220 		/*
1221 		 * extent no longer exists - we could flush the btree
1222 		 * write buffer and retry to verify, but no need:
1223 		 */
1224 		return 0;
1225 	}
1226 
1227 	if (extent_has_stripe_ptr(k, s->key.k.p.offset))
1228 		goto out;
1229 
1230 	ptr_c = bkey_matches_stripe(v, k, &block);
1231 	/*
1232 	 * It doesn't generally make sense to erasure code cached ptrs:
1233 	 * XXX: should we be incrementing a counter?
1234 	 */
1235 	if (!ptr_c || ptr_c->cached)
1236 		goto out;
1237 
1238 	dev = v->ptrs[block].dev;
1239 
1240 	n = bch2_trans_kmalloc(trans, bkey_bytes(k.k) + sizeof(stripe_ptr));
1241 	ret = PTR_ERR_OR_ZERO(n);
1242 	if (ret)
1243 		goto out;
1244 
1245 	bkey_reassemble(n, k);
1246 
1247 	bch2_bkey_drop_ptrs(bkey_i_to_s(n), ptr, ptr->dev != dev);
1248 	ec_ptr = bch2_bkey_has_device(bkey_i_to_s(n), dev);
1249 	BUG_ON(!ec_ptr);
1250 
1251 	stripe_ptr = (struct bch_extent_stripe_ptr) {
1252 		.type = 1 << BCH_EXTENT_ENTRY_stripe_ptr,
1253 		.block		= block,
1254 		.redundancy	= v->nr_redundant,
1255 		.idx		= s->key.k.p.offset,
1256 	};
1257 
1258 	__extent_entry_insert(n,
1259 			(union bch_extent_entry *) ec_ptr,
1260 			(union bch_extent_entry *) &stripe_ptr);
1261 
1262 	ret = bch2_trans_update(trans, &iter, n, 0);
1263 out:
1264 	bch2_trans_iter_exit(trans, &iter);
1265 	return ret;
1266 }
1267 
1268 static int ec_stripe_update_bucket(struct btree_trans *trans, struct ec_stripe_buf *s,
1269 				   unsigned block)
1270 {
1271 	struct bch_fs *c = trans->c;
1272 	struct bch_stripe *v = &bkey_i_to_stripe(&s->key)->v;
1273 	struct bch_extent_ptr bucket = v->ptrs[block];
1274 	struct bpos bucket_pos = PTR_BUCKET_POS(c, &bucket);
1275 	struct bpos bp_pos = POS_MIN;
1276 	int ret = 0;
1277 
1278 	while (1) {
1279 		ret = commit_do(trans, NULL, NULL,
1280 				BCH_TRANS_COMMIT_no_check_rw|
1281 				BCH_TRANS_COMMIT_no_enospc,
1282 			ec_stripe_update_extent(trans, bucket_pos, bucket.gen,
1283 						s, &bp_pos));
1284 		if (ret)
1285 			break;
1286 		if (bkey_eq(bp_pos, POS_MAX))
1287 			break;
1288 
1289 		bp_pos = bpos_nosnap_successor(bp_pos);
1290 	}
1291 
1292 	return ret;
1293 }
1294 
1295 static int ec_stripe_update_extents(struct bch_fs *c, struct ec_stripe_buf *s)
1296 {
1297 	struct btree_trans *trans = bch2_trans_get(c);
1298 	struct bch_stripe *v = &bkey_i_to_stripe(&s->key)->v;
1299 	unsigned i, nr_data = v->nr_blocks - v->nr_redundant;
1300 	int ret = 0;
1301 
1302 	ret = bch2_btree_write_buffer_flush_sync(trans);
1303 	if (ret)
1304 		goto err;
1305 
1306 	for (i = 0; i < nr_data; i++) {
1307 		ret = ec_stripe_update_bucket(trans, s, i);
1308 		if (ret)
1309 			break;
1310 	}
1311 err:
1312 	bch2_trans_put(trans);
1313 
1314 	return ret;
1315 }
1316 
1317 static void zero_out_rest_of_ec_bucket(struct bch_fs *c,
1318 				       struct ec_stripe_new *s,
1319 				       unsigned block,
1320 				       struct open_bucket *ob)
1321 {
1322 	struct bch_dev *ca = bch_dev_bkey_exists(c, ob->dev);
1323 	unsigned offset = ca->mi.bucket_size - ob->sectors_free;
1324 	int ret;
1325 
1326 	if (!bch2_dev_get_ioref(ca, WRITE)) {
1327 		s->err = -BCH_ERR_erofs_no_writes;
1328 		return;
1329 	}
1330 
1331 	memset(s->new_stripe.data[block] + (offset << 9),
1332 	       0,
1333 	       ob->sectors_free << 9);
1334 
1335 	ret = blkdev_issue_zeroout(ca->disk_sb.bdev,
1336 			ob->bucket * ca->mi.bucket_size + offset,
1337 			ob->sectors_free,
1338 			GFP_KERNEL, 0);
1339 
1340 	percpu_ref_put(&ca->io_ref);
1341 
1342 	if (ret)
1343 		s->err = ret;
1344 }
1345 
1346 void bch2_ec_stripe_new_free(struct bch_fs *c, struct ec_stripe_new *s)
1347 {
1348 	if (s->idx)
1349 		bch2_stripe_close(c, s);
1350 	kfree(s);
1351 }
1352 
1353 /*
1354  * data buckets of new stripe all written: create the stripe
1355  */
1356 static void ec_stripe_create(struct ec_stripe_new *s)
1357 {
1358 	struct bch_fs *c = s->c;
1359 	struct open_bucket *ob;
1360 	struct bch_stripe *v = &bkey_i_to_stripe(&s->new_stripe.key)->v;
1361 	unsigned i, nr_data = v->nr_blocks - v->nr_redundant;
1362 	int ret;
1363 
1364 	BUG_ON(s->h->s == s);
1365 
1366 	closure_sync(&s->iodone);
1367 
1368 	if (!s->err) {
1369 		for (i = 0; i < nr_data; i++)
1370 			if (s->blocks[i]) {
1371 				ob = c->open_buckets + s->blocks[i];
1372 
1373 				if (ob->sectors_free)
1374 					zero_out_rest_of_ec_bucket(c, s, i, ob);
1375 			}
1376 	}
1377 
1378 	if (s->err) {
1379 		if (!bch2_err_matches(s->err, EROFS))
1380 			bch_err(c, "error creating stripe: error writing data buckets");
1381 		goto err;
1382 	}
1383 
1384 	if (s->have_existing_stripe) {
1385 		ec_validate_checksums(c, &s->existing_stripe);
1386 
1387 		if (ec_do_recov(c, &s->existing_stripe)) {
1388 			bch_err(c, "error creating stripe: error reading existing stripe");
1389 			goto err;
1390 		}
1391 
1392 		for (i = 0; i < nr_data; i++)
1393 			if (stripe_blockcount_get(&bkey_i_to_stripe(&s->existing_stripe.key)->v, i))
1394 				swap(s->new_stripe.data[i],
1395 				     s->existing_stripe.data[i]);
1396 
1397 		ec_stripe_buf_exit(&s->existing_stripe);
1398 	}
1399 
1400 	BUG_ON(!s->allocated);
1401 	BUG_ON(!s->idx);
1402 
1403 	ec_generate_ec(&s->new_stripe);
1404 
1405 	ec_generate_checksums(&s->new_stripe);
1406 
1407 	/* write p/q: */
1408 	for (i = nr_data; i < v->nr_blocks; i++)
1409 		ec_block_io(c, &s->new_stripe, REQ_OP_WRITE, i, &s->iodone);
1410 	closure_sync(&s->iodone);
1411 
1412 	if (ec_nr_failed(&s->new_stripe)) {
1413 		bch_err(c, "error creating stripe: error writing redundancy buckets");
1414 		goto err;
1415 	}
1416 
1417 	ret = bch2_trans_do(c, &s->res, NULL,
1418 			    BCH_TRANS_COMMIT_no_check_rw|
1419 			    BCH_TRANS_COMMIT_no_enospc,
1420 			    ec_stripe_key_update(trans,
1421 					bkey_i_to_stripe(&s->new_stripe.key),
1422 					!s->have_existing_stripe));
1423 	bch_err_msg(c, ret, "creating stripe key");
1424 	if (ret) {
1425 		goto err;
1426 	}
1427 
1428 	ret = ec_stripe_update_extents(c, &s->new_stripe);
1429 	bch_err_msg(c, ret, "error updating extents");
1430 	if (ret)
1431 		goto err;
1432 err:
1433 	bch2_disk_reservation_put(c, &s->res);
1434 
1435 	for (i = 0; i < v->nr_blocks; i++)
1436 		if (s->blocks[i]) {
1437 			ob = c->open_buckets + s->blocks[i];
1438 
1439 			if (i < nr_data) {
1440 				ob->ec = NULL;
1441 				__bch2_open_bucket_put(c, ob);
1442 			} else {
1443 				bch2_open_bucket_put(c, ob);
1444 			}
1445 		}
1446 
1447 	mutex_lock(&c->ec_stripe_new_lock);
1448 	list_del(&s->list);
1449 	mutex_unlock(&c->ec_stripe_new_lock);
1450 	wake_up(&c->ec_stripe_new_wait);
1451 
1452 	ec_stripe_buf_exit(&s->existing_stripe);
1453 	ec_stripe_buf_exit(&s->new_stripe);
1454 	closure_debug_destroy(&s->iodone);
1455 
1456 	ec_stripe_new_put(c, s, STRIPE_REF_stripe);
1457 }
1458 
1459 static struct ec_stripe_new *get_pending_stripe(struct bch_fs *c)
1460 {
1461 	struct ec_stripe_new *s;
1462 
1463 	mutex_lock(&c->ec_stripe_new_lock);
1464 	list_for_each_entry(s, &c->ec_stripe_new_list, list)
1465 		if (!atomic_read(&s->ref[STRIPE_REF_io]))
1466 			goto out;
1467 	s = NULL;
1468 out:
1469 	mutex_unlock(&c->ec_stripe_new_lock);
1470 
1471 	return s;
1472 }
1473 
1474 static void ec_stripe_create_work(struct work_struct *work)
1475 {
1476 	struct bch_fs *c = container_of(work,
1477 		struct bch_fs, ec_stripe_create_work);
1478 	struct ec_stripe_new *s;
1479 
1480 	while ((s = get_pending_stripe(c)))
1481 		ec_stripe_create(s);
1482 
1483 	bch2_write_ref_put(c, BCH_WRITE_REF_stripe_create);
1484 }
1485 
1486 void bch2_ec_do_stripe_creates(struct bch_fs *c)
1487 {
1488 	bch2_write_ref_get(c, BCH_WRITE_REF_stripe_create);
1489 
1490 	if (!queue_work(system_long_wq, &c->ec_stripe_create_work))
1491 		bch2_write_ref_put(c, BCH_WRITE_REF_stripe_create);
1492 }
1493 
1494 static void ec_stripe_set_pending(struct bch_fs *c, struct ec_stripe_head *h)
1495 {
1496 	struct ec_stripe_new *s = h->s;
1497 
1498 	BUG_ON(!s->allocated && !s->err);
1499 
1500 	h->s		= NULL;
1501 	s->pending	= true;
1502 
1503 	mutex_lock(&c->ec_stripe_new_lock);
1504 	list_add(&s->list, &c->ec_stripe_new_list);
1505 	mutex_unlock(&c->ec_stripe_new_lock);
1506 
1507 	ec_stripe_new_put(c, s, STRIPE_REF_io);
1508 }
1509 
1510 void bch2_ec_bucket_cancel(struct bch_fs *c, struct open_bucket *ob)
1511 {
1512 	struct ec_stripe_new *s = ob->ec;
1513 
1514 	s->err = -EIO;
1515 }
1516 
1517 void *bch2_writepoint_ec_buf(struct bch_fs *c, struct write_point *wp)
1518 {
1519 	struct open_bucket *ob = ec_open_bucket(c, &wp->ptrs);
1520 	struct bch_dev *ca;
1521 	unsigned offset;
1522 
1523 	if (!ob)
1524 		return NULL;
1525 
1526 	BUG_ON(!ob->ec->new_stripe.data[ob->ec_idx]);
1527 
1528 	ca	= bch_dev_bkey_exists(c, ob->dev);
1529 	offset	= ca->mi.bucket_size - ob->sectors_free;
1530 
1531 	return ob->ec->new_stripe.data[ob->ec_idx] + (offset << 9);
1532 }
1533 
1534 static int unsigned_cmp(const void *_l, const void *_r)
1535 {
1536 	unsigned l = *((const unsigned *) _l);
1537 	unsigned r = *((const unsigned *) _r);
1538 
1539 	return cmp_int(l, r);
1540 }
1541 
1542 /* pick most common bucket size: */
1543 static unsigned pick_blocksize(struct bch_fs *c,
1544 			       struct bch_devs_mask *devs)
1545 {
1546 	unsigned nr = 0, sizes[BCH_SB_MEMBERS_MAX];
1547 	struct {
1548 		unsigned nr, size;
1549 	} cur = { 0, 0 }, best = { 0, 0 };
1550 
1551 	for_each_member_device_rcu(c, ca, devs)
1552 		sizes[nr++] = ca->mi.bucket_size;
1553 
1554 	sort(sizes, nr, sizeof(unsigned), unsigned_cmp, NULL);
1555 
1556 	for (unsigned i = 0; i < nr; i++) {
1557 		if (sizes[i] != cur.size) {
1558 			if (cur.nr > best.nr)
1559 				best = cur;
1560 
1561 			cur.nr = 0;
1562 			cur.size = sizes[i];
1563 		}
1564 
1565 		cur.nr++;
1566 	}
1567 
1568 	if (cur.nr > best.nr)
1569 		best = cur;
1570 
1571 	return best.size;
1572 }
1573 
1574 static bool may_create_new_stripe(struct bch_fs *c)
1575 {
1576 	return false;
1577 }
1578 
1579 static void ec_stripe_key_init(struct bch_fs *c,
1580 			       struct bkey_i *k,
1581 			       unsigned nr_data,
1582 			       unsigned nr_parity,
1583 			       unsigned stripe_size)
1584 {
1585 	struct bkey_i_stripe *s = bkey_stripe_init(k);
1586 	unsigned u64s;
1587 
1588 	s->v.sectors			= cpu_to_le16(stripe_size);
1589 	s->v.algorithm			= 0;
1590 	s->v.nr_blocks			= nr_data + nr_parity;
1591 	s->v.nr_redundant		= nr_parity;
1592 	s->v.csum_granularity_bits	= ilog2(c->opts.encoded_extent_max >> 9);
1593 	s->v.csum_type			= BCH_CSUM_crc32c;
1594 	s->v.pad			= 0;
1595 
1596 	while ((u64s = stripe_val_u64s(&s->v)) > BKEY_VAL_U64s_MAX) {
1597 		BUG_ON(1 << s->v.csum_granularity_bits >=
1598 		       le16_to_cpu(s->v.sectors) ||
1599 		       s->v.csum_granularity_bits == U8_MAX);
1600 		s->v.csum_granularity_bits++;
1601 	}
1602 
1603 	set_bkey_val_u64s(&s->k, u64s);
1604 }
1605 
1606 static int ec_new_stripe_alloc(struct bch_fs *c, struct ec_stripe_head *h)
1607 {
1608 	struct ec_stripe_new *s;
1609 
1610 	lockdep_assert_held(&h->lock);
1611 
1612 	s = kzalloc(sizeof(*s), GFP_KERNEL);
1613 	if (!s)
1614 		return -BCH_ERR_ENOMEM_ec_new_stripe_alloc;
1615 
1616 	mutex_init(&s->lock);
1617 	closure_init(&s->iodone, NULL);
1618 	atomic_set(&s->ref[STRIPE_REF_stripe], 1);
1619 	atomic_set(&s->ref[STRIPE_REF_io], 1);
1620 	s->c		= c;
1621 	s->h		= h;
1622 	s->nr_data	= min_t(unsigned, h->nr_active_devs,
1623 				BCH_BKEY_PTRS_MAX) - h->redundancy;
1624 	s->nr_parity	= h->redundancy;
1625 
1626 	ec_stripe_key_init(c, &s->new_stripe.key,
1627 			   s->nr_data, s->nr_parity, h->blocksize);
1628 
1629 	h->s = s;
1630 	return 0;
1631 }
1632 
1633 static struct ec_stripe_head *
1634 ec_new_stripe_head_alloc(struct bch_fs *c, unsigned target,
1635 			 unsigned algo, unsigned redundancy,
1636 			 enum bch_watermark watermark)
1637 {
1638 	struct ec_stripe_head *h;
1639 
1640 	h = kzalloc(sizeof(*h), GFP_KERNEL);
1641 	if (!h)
1642 		return NULL;
1643 
1644 	mutex_init(&h->lock);
1645 	BUG_ON(!mutex_trylock(&h->lock));
1646 
1647 	h->target	= target;
1648 	h->algo		= algo;
1649 	h->redundancy	= redundancy;
1650 	h->watermark	= watermark;
1651 
1652 	rcu_read_lock();
1653 	h->devs = target_rw_devs(c, BCH_DATA_user, target);
1654 
1655 	for_each_member_device_rcu(c, ca, &h->devs)
1656 		if (!ca->mi.durability)
1657 			__clear_bit(ca->dev_idx, h->devs.d);
1658 
1659 	h->blocksize = pick_blocksize(c, &h->devs);
1660 
1661 	for_each_member_device_rcu(c, ca, &h->devs)
1662 		if (ca->mi.bucket_size == h->blocksize)
1663 			h->nr_active_devs++;
1664 
1665 	rcu_read_unlock();
1666 
1667 	/*
1668 	 * If we only have redundancy + 1 devices, we're better off with just
1669 	 * replication:
1670 	 */
1671 	if (h->nr_active_devs < h->redundancy + 2)
1672 		bch_err(c, "insufficient devices available to create stripe (have %u, need %u) - mismatched bucket sizes?",
1673 			h->nr_active_devs, h->redundancy + 2);
1674 
1675 	list_add(&h->list, &c->ec_stripe_head_list);
1676 	return h;
1677 }
1678 
1679 void bch2_ec_stripe_head_put(struct bch_fs *c, struct ec_stripe_head *h)
1680 {
1681 	if (h->s &&
1682 	    h->s->allocated &&
1683 	    bitmap_weight(h->s->blocks_allocated,
1684 			  h->s->nr_data) == h->s->nr_data)
1685 		ec_stripe_set_pending(c, h);
1686 
1687 	mutex_unlock(&h->lock);
1688 }
1689 
1690 static struct ec_stripe_head *
1691 __bch2_ec_stripe_head_get(struct btree_trans *trans,
1692 			  unsigned target,
1693 			  unsigned algo,
1694 			  unsigned redundancy,
1695 			  enum bch_watermark watermark)
1696 {
1697 	struct bch_fs *c = trans->c;
1698 	struct ec_stripe_head *h;
1699 	int ret;
1700 
1701 	if (!redundancy)
1702 		return NULL;
1703 
1704 	ret = bch2_trans_mutex_lock(trans, &c->ec_stripe_head_lock);
1705 	if (ret)
1706 		return ERR_PTR(ret);
1707 
1708 	if (test_bit(BCH_FS_going_ro, &c->flags)) {
1709 		h = ERR_PTR(-BCH_ERR_erofs_no_writes);
1710 		goto found;
1711 	}
1712 
1713 	list_for_each_entry(h, &c->ec_stripe_head_list, list)
1714 		if (h->target		== target &&
1715 		    h->algo		== algo &&
1716 		    h->redundancy	== redundancy &&
1717 		    h->watermark	== watermark) {
1718 			ret = bch2_trans_mutex_lock(trans, &h->lock);
1719 			if (ret)
1720 				h = ERR_PTR(ret);
1721 			goto found;
1722 		}
1723 
1724 	h = ec_new_stripe_head_alloc(c, target, algo, redundancy, watermark);
1725 found:
1726 	if (!IS_ERR_OR_NULL(h) &&
1727 	    h->nr_active_devs < h->redundancy + 2) {
1728 		mutex_unlock(&h->lock);
1729 		h = NULL;
1730 	}
1731 	mutex_unlock(&c->ec_stripe_head_lock);
1732 	return h;
1733 }
1734 
1735 static int new_stripe_alloc_buckets(struct btree_trans *trans, struct ec_stripe_head *h,
1736 				    enum bch_watermark watermark, struct closure *cl)
1737 {
1738 	struct bch_fs *c = trans->c;
1739 	struct bch_devs_mask devs = h->devs;
1740 	struct open_bucket *ob;
1741 	struct open_buckets buckets;
1742 	struct bch_stripe *v = &bkey_i_to_stripe(&h->s->new_stripe.key)->v;
1743 	unsigned i, j, nr_have_parity = 0, nr_have_data = 0;
1744 	bool have_cache = true;
1745 	int ret = 0;
1746 
1747 	BUG_ON(v->nr_blocks	!= h->s->nr_data + h->s->nr_parity);
1748 	BUG_ON(v->nr_redundant	!= h->s->nr_parity);
1749 
1750 	for_each_set_bit(i, h->s->blocks_gotten, v->nr_blocks) {
1751 		__clear_bit(v->ptrs[i].dev, devs.d);
1752 		if (i < h->s->nr_data)
1753 			nr_have_data++;
1754 		else
1755 			nr_have_parity++;
1756 	}
1757 
1758 	BUG_ON(nr_have_data	> h->s->nr_data);
1759 	BUG_ON(nr_have_parity	> h->s->nr_parity);
1760 
1761 	buckets.nr = 0;
1762 	if (nr_have_parity < h->s->nr_parity) {
1763 		ret = bch2_bucket_alloc_set_trans(trans, &buckets,
1764 					    &h->parity_stripe,
1765 					    &devs,
1766 					    h->s->nr_parity,
1767 					    &nr_have_parity,
1768 					    &have_cache, 0,
1769 					    BCH_DATA_parity,
1770 					    watermark,
1771 					    cl);
1772 
1773 		open_bucket_for_each(c, &buckets, ob, i) {
1774 			j = find_next_zero_bit(h->s->blocks_gotten,
1775 					       h->s->nr_data + h->s->nr_parity,
1776 					       h->s->nr_data);
1777 			BUG_ON(j >= h->s->nr_data + h->s->nr_parity);
1778 
1779 			h->s->blocks[j] = buckets.v[i];
1780 			v->ptrs[j] = bch2_ob_ptr(c, ob);
1781 			__set_bit(j, h->s->blocks_gotten);
1782 		}
1783 
1784 		if (ret)
1785 			return ret;
1786 	}
1787 
1788 	buckets.nr = 0;
1789 	if (nr_have_data < h->s->nr_data) {
1790 		ret = bch2_bucket_alloc_set_trans(trans, &buckets,
1791 					    &h->block_stripe,
1792 					    &devs,
1793 					    h->s->nr_data,
1794 					    &nr_have_data,
1795 					    &have_cache, 0,
1796 					    BCH_DATA_user,
1797 					    watermark,
1798 					    cl);
1799 
1800 		open_bucket_for_each(c, &buckets, ob, i) {
1801 			j = find_next_zero_bit(h->s->blocks_gotten,
1802 					       h->s->nr_data, 0);
1803 			BUG_ON(j >= h->s->nr_data);
1804 
1805 			h->s->blocks[j] = buckets.v[i];
1806 			v->ptrs[j] = bch2_ob_ptr(c, ob);
1807 			__set_bit(j, h->s->blocks_gotten);
1808 		}
1809 
1810 		if (ret)
1811 			return ret;
1812 	}
1813 
1814 	return 0;
1815 }
1816 
1817 /* XXX: doesn't obey target: */
1818 static s64 get_existing_stripe(struct bch_fs *c,
1819 			       struct ec_stripe_head *head)
1820 {
1821 	ec_stripes_heap *h = &c->ec_stripes_heap;
1822 	struct stripe *m;
1823 	size_t heap_idx;
1824 	u64 stripe_idx;
1825 	s64 ret = -1;
1826 
1827 	if (may_create_new_stripe(c))
1828 		return -1;
1829 
1830 	mutex_lock(&c->ec_stripes_heap_lock);
1831 	for (heap_idx = 0; heap_idx < h->used; heap_idx++) {
1832 		/* No blocks worth reusing, stripe will just be deleted: */
1833 		if (!h->data[heap_idx].blocks_nonempty)
1834 			continue;
1835 
1836 		stripe_idx = h->data[heap_idx].idx;
1837 
1838 		m = genradix_ptr(&c->stripes, stripe_idx);
1839 
1840 		if (m->algorithm	== head->algo &&
1841 		    m->nr_redundant	== head->redundancy &&
1842 		    m->sectors		== head->blocksize &&
1843 		    m->blocks_nonempty	< m->nr_blocks - m->nr_redundant &&
1844 		    bch2_try_open_stripe(c, head->s, stripe_idx)) {
1845 			ret = stripe_idx;
1846 			break;
1847 		}
1848 	}
1849 	mutex_unlock(&c->ec_stripes_heap_lock);
1850 	return ret;
1851 }
1852 
1853 static int __bch2_ec_stripe_head_reuse(struct btree_trans *trans, struct ec_stripe_head *h)
1854 {
1855 	struct bch_fs *c = trans->c;
1856 	struct bch_stripe *new_v = &bkey_i_to_stripe(&h->s->new_stripe.key)->v;
1857 	struct bch_stripe *existing_v;
1858 	unsigned i;
1859 	s64 idx;
1860 	int ret;
1861 
1862 	/*
1863 	 * If we can't allocate a new stripe, and there's no stripes with empty
1864 	 * blocks for us to reuse, that means we have to wait on copygc:
1865 	 */
1866 	idx = get_existing_stripe(c, h);
1867 	if (idx < 0)
1868 		return -BCH_ERR_stripe_alloc_blocked;
1869 
1870 	ret = get_stripe_key_trans(trans, idx, &h->s->existing_stripe);
1871 	bch2_fs_fatal_err_on(ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart), c,
1872 			     "reading stripe key: %s", bch2_err_str(ret));
1873 	if (ret) {
1874 		bch2_stripe_close(c, h->s);
1875 		return ret;
1876 	}
1877 
1878 	existing_v = &bkey_i_to_stripe(&h->s->existing_stripe.key)->v;
1879 
1880 	BUG_ON(existing_v->nr_redundant != h->s->nr_parity);
1881 	h->s->nr_data = existing_v->nr_blocks -
1882 		existing_v->nr_redundant;
1883 
1884 	ret = ec_stripe_buf_init(&h->s->existing_stripe, 0, h->blocksize);
1885 	if (ret) {
1886 		bch2_stripe_close(c, h->s);
1887 		return ret;
1888 	}
1889 
1890 	BUG_ON(h->s->existing_stripe.size != h->blocksize);
1891 	BUG_ON(h->s->existing_stripe.size != le16_to_cpu(existing_v->sectors));
1892 
1893 	/*
1894 	 * Free buckets we initially allocated - they might conflict with
1895 	 * blocks from the stripe we're reusing:
1896 	 */
1897 	for_each_set_bit(i, h->s->blocks_gotten, new_v->nr_blocks) {
1898 		bch2_open_bucket_put(c, c->open_buckets + h->s->blocks[i]);
1899 		h->s->blocks[i] = 0;
1900 	}
1901 	memset(h->s->blocks_gotten, 0, sizeof(h->s->blocks_gotten));
1902 	memset(h->s->blocks_allocated, 0, sizeof(h->s->blocks_allocated));
1903 
1904 	for (i = 0; i < existing_v->nr_blocks; i++) {
1905 		if (stripe_blockcount_get(existing_v, i)) {
1906 			__set_bit(i, h->s->blocks_gotten);
1907 			__set_bit(i, h->s->blocks_allocated);
1908 		}
1909 
1910 		ec_block_io(c, &h->s->existing_stripe, READ, i, &h->s->iodone);
1911 	}
1912 
1913 	bkey_copy(&h->s->new_stripe.key, &h->s->existing_stripe.key);
1914 	h->s->have_existing_stripe = true;
1915 
1916 	return 0;
1917 }
1918 
1919 static int __bch2_ec_stripe_head_reserve(struct btree_trans *trans, struct ec_stripe_head *h)
1920 {
1921 	struct bch_fs *c = trans->c;
1922 	struct btree_iter iter;
1923 	struct bkey_s_c k;
1924 	struct bpos min_pos = POS(0, 1);
1925 	struct bpos start_pos = bpos_max(min_pos, POS(0, c->ec_stripe_hint));
1926 	int ret;
1927 
1928 	if (!h->s->res.sectors) {
1929 		ret = bch2_disk_reservation_get(c, &h->s->res,
1930 					h->blocksize,
1931 					h->s->nr_parity,
1932 					BCH_DISK_RESERVATION_NOFAIL);
1933 		if (ret)
1934 			return ret;
1935 	}
1936 
1937 	for_each_btree_key_norestart(trans, iter, BTREE_ID_stripes, start_pos,
1938 			   BTREE_ITER_SLOTS|BTREE_ITER_INTENT, k, ret) {
1939 		if (bkey_gt(k.k->p, POS(0, U32_MAX))) {
1940 			if (start_pos.offset) {
1941 				start_pos = min_pos;
1942 				bch2_btree_iter_set_pos(&iter, start_pos);
1943 				continue;
1944 			}
1945 
1946 			ret = -BCH_ERR_ENOSPC_stripe_create;
1947 			break;
1948 		}
1949 
1950 		if (bkey_deleted(k.k) &&
1951 		    bch2_try_open_stripe(c, h->s, k.k->p.offset))
1952 			break;
1953 	}
1954 
1955 	c->ec_stripe_hint = iter.pos.offset;
1956 
1957 	if (ret)
1958 		goto err;
1959 
1960 	ret = ec_stripe_mem_alloc(trans, &iter);
1961 	if (ret) {
1962 		bch2_stripe_close(c, h->s);
1963 		goto err;
1964 	}
1965 
1966 	h->s->new_stripe.key.k.p = iter.pos;
1967 out:
1968 	bch2_trans_iter_exit(trans, &iter);
1969 	return ret;
1970 err:
1971 	bch2_disk_reservation_put(c, &h->s->res);
1972 	goto out;
1973 }
1974 
1975 struct ec_stripe_head *bch2_ec_stripe_head_get(struct btree_trans *trans,
1976 					       unsigned target,
1977 					       unsigned algo,
1978 					       unsigned redundancy,
1979 					       enum bch_watermark watermark,
1980 					       struct closure *cl)
1981 {
1982 	struct bch_fs *c = trans->c;
1983 	struct ec_stripe_head *h;
1984 	bool waiting = false;
1985 	int ret;
1986 
1987 	h = __bch2_ec_stripe_head_get(trans, target, algo, redundancy, watermark);
1988 	if (IS_ERR_OR_NULL(h))
1989 		return h;
1990 
1991 	if (!h->s) {
1992 		ret = ec_new_stripe_alloc(c, h);
1993 		if (ret) {
1994 			bch_err(c, "failed to allocate new stripe");
1995 			goto err;
1996 		}
1997 	}
1998 
1999 	if (h->s->allocated)
2000 		goto allocated;
2001 
2002 	if (h->s->have_existing_stripe)
2003 		goto alloc_existing;
2004 
2005 	/* First, try to allocate a full stripe: */
2006 	ret =   new_stripe_alloc_buckets(trans, h, BCH_WATERMARK_stripe, NULL) ?:
2007 		__bch2_ec_stripe_head_reserve(trans, h);
2008 	if (!ret)
2009 		goto allocate_buf;
2010 	if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||
2011 	    bch2_err_matches(ret, ENOMEM))
2012 		goto err;
2013 
2014 	/*
2015 	 * Not enough buckets available for a full stripe: we must reuse an
2016 	 * existing stripe:
2017 	 */
2018 	while (1) {
2019 		ret = __bch2_ec_stripe_head_reuse(trans, h);
2020 		if (!ret)
2021 			break;
2022 		if (waiting || !cl || ret != -BCH_ERR_stripe_alloc_blocked)
2023 			goto err;
2024 
2025 		if (watermark == BCH_WATERMARK_copygc) {
2026 			ret =   new_stripe_alloc_buckets(trans, h, watermark, NULL) ?:
2027 				__bch2_ec_stripe_head_reserve(trans, h);
2028 			if (ret)
2029 				goto err;
2030 			goto allocate_buf;
2031 		}
2032 
2033 		/* XXX freelist_wait? */
2034 		closure_wait(&c->freelist_wait, cl);
2035 		waiting = true;
2036 	}
2037 
2038 	if (waiting)
2039 		closure_wake_up(&c->freelist_wait);
2040 alloc_existing:
2041 	/*
2042 	 * Retry allocating buckets, with the watermark for this
2043 	 * particular write:
2044 	 */
2045 	ret = new_stripe_alloc_buckets(trans, h, watermark, cl);
2046 	if (ret)
2047 		goto err;
2048 
2049 allocate_buf:
2050 	ret = ec_stripe_buf_init(&h->s->new_stripe, 0, h->blocksize);
2051 	if (ret)
2052 		goto err;
2053 
2054 	h->s->allocated = true;
2055 allocated:
2056 	BUG_ON(!h->s->idx);
2057 	BUG_ON(!h->s->new_stripe.data[0]);
2058 	BUG_ON(trans->restarted);
2059 	return h;
2060 err:
2061 	bch2_ec_stripe_head_put(c, h);
2062 	return ERR_PTR(ret);
2063 }
2064 
2065 static void __bch2_ec_stop(struct bch_fs *c, struct bch_dev *ca)
2066 {
2067 	struct ec_stripe_head *h;
2068 	struct open_bucket *ob;
2069 	unsigned i;
2070 
2071 	mutex_lock(&c->ec_stripe_head_lock);
2072 	list_for_each_entry(h, &c->ec_stripe_head_list, list) {
2073 		mutex_lock(&h->lock);
2074 		if (!h->s)
2075 			goto unlock;
2076 
2077 		if (!ca)
2078 			goto found;
2079 
2080 		for (i = 0; i < bkey_i_to_stripe(&h->s->new_stripe.key)->v.nr_blocks; i++) {
2081 			if (!h->s->blocks[i])
2082 				continue;
2083 
2084 			ob = c->open_buckets + h->s->blocks[i];
2085 			if (ob->dev == ca->dev_idx)
2086 				goto found;
2087 		}
2088 		goto unlock;
2089 found:
2090 		h->s->err = -BCH_ERR_erofs_no_writes;
2091 		ec_stripe_set_pending(c, h);
2092 unlock:
2093 		mutex_unlock(&h->lock);
2094 	}
2095 	mutex_unlock(&c->ec_stripe_head_lock);
2096 }
2097 
2098 void bch2_ec_stop_dev(struct bch_fs *c, struct bch_dev *ca)
2099 {
2100 	__bch2_ec_stop(c, ca);
2101 }
2102 
2103 void bch2_fs_ec_stop(struct bch_fs *c)
2104 {
2105 	__bch2_ec_stop(c, NULL);
2106 }
2107 
2108 static bool bch2_fs_ec_flush_done(struct bch_fs *c)
2109 {
2110 	bool ret;
2111 
2112 	mutex_lock(&c->ec_stripe_new_lock);
2113 	ret = list_empty(&c->ec_stripe_new_list);
2114 	mutex_unlock(&c->ec_stripe_new_lock);
2115 
2116 	return ret;
2117 }
2118 
2119 void bch2_fs_ec_flush(struct bch_fs *c)
2120 {
2121 	wait_event(c->ec_stripe_new_wait, bch2_fs_ec_flush_done(c));
2122 }
2123 
2124 int bch2_stripes_read(struct bch_fs *c)
2125 {
2126 	int ret = bch2_trans_run(c,
2127 		for_each_btree_key(trans, iter, BTREE_ID_stripes, POS_MIN,
2128 				   BTREE_ITER_PREFETCH, k, ({
2129 			if (k.k->type != KEY_TYPE_stripe)
2130 				continue;
2131 
2132 			ret = __ec_stripe_mem_alloc(c, k.k->p.offset, GFP_KERNEL);
2133 			if (ret)
2134 				break;
2135 
2136 			const struct bch_stripe *s = bkey_s_c_to_stripe(k).v;
2137 
2138 			struct stripe *m = genradix_ptr(&c->stripes, k.k->p.offset);
2139 			m->sectors	= le16_to_cpu(s->sectors);
2140 			m->algorithm	= s->algorithm;
2141 			m->nr_blocks	= s->nr_blocks;
2142 			m->nr_redundant	= s->nr_redundant;
2143 			m->blocks_nonempty = 0;
2144 
2145 			for (unsigned i = 0; i < s->nr_blocks; i++)
2146 				m->blocks_nonempty += !!stripe_blockcount_get(s, i);
2147 
2148 			bch2_stripes_heap_insert(c, m, k.k->p.offset);
2149 			0;
2150 		})));
2151 	bch_err_fn(c, ret);
2152 	return ret;
2153 }
2154 
2155 void bch2_stripes_heap_to_text(struct printbuf *out, struct bch_fs *c)
2156 {
2157 	ec_stripes_heap *h = &c->ec_stripes_heap;
2158 	struct stripe *m;
2159 	size_t i;
2160 
2161 	mutex_lock(&c->ec_stripes_heap_lock);
2162 	for (i = 0; i < min_t(size_t, h->used, 50); i++) {
2163 		m = genradix_ptr(&c->stripes, h->data[i].idx);
2164 
2165 		prt_printf(out, "%zu %u/%u+%u", h->data[i].idx,
2166 		       h->data[i].blocks_nonempty,
2167 		       m->nr_blocks - m->nr_redundant,
2168 		       m->nr_redundant);
2169 		if (bch2_stripe_is_open(c, h->data[i].idx))
2170 			prt_str(out, " open");
2171 		prt_newline(out);
2172 	}
2173 	mutex_unlock(&c->ec_stripes_heap_lock);
2174 }
2175 
2176 void bch2_new_stripes_to_text(struct printbuf *out, struct bch_fs *c)
2177 {
2178 	struct ec_stripe_head *h;
2179 	struct ec_stripe_new *s;
2180 
2181 	mutex_lock(&c->ec_stripe_head_lock);
2182 	list_for_each_entry(h, &c->ec_stripe_head_list, list) {
2183 		prt_printf(out, "target %u algo %u redundancy %u %s:\n",
2184 		       h->target, h->algo, h->redundancy,
2185 		       bch2_watermarks[h->watermark]);
2186 
2187 		if (h->s)
2188 			prt_printf(out, "\tidx %llu blocks %u+%u allocated %u\n",
2189 			       h->s->idx, h->s->nr_data, h->s->nr_parity,
2190 			       bitmap_weight(h->s->blocks_allocated,
2191 					     h->s->nr_data));
2192 	}
2193 	mutex_unlock(&c->ec_stripe_head_lock);
2194 
2195 	prt_printf(out, "in flight:\n");
2196 
2197 	mutex_lock(&c->ec_stripe_new_lock);
2198 	list_for_each_entry(s, &c->ec_stripe_new_list, list) {
2199 		prt_printf(out, "\tidx %llu blocks %u+%u ref %u %u %s\n",
2200 			   s->idx, s->nr_data, s->nr_parity,
2201 			   atomic_read(&s->ref[STRIPE_REF_io]),
2202 			   atomic_read(&s->ref[STRIPE_REF_stripe]),
2203 			   bch2_watermarks[s->h->watermark]);
2204 	}
2205 	mutex_unlock(&c->ec_stripe_new_lock);
2206 }
2207 
2208 void bch2_fs_ec_exit(struct bch_fs *c)
2209 {
2210 	struct ec_stripe_head *h;
2211 	unsigned i;
2212 
2213 	while (1) {
2214 		mutex_lock(&c->ec_stripe_head_lock);
2215 		h = list_first_entry_or_null(&c->ec_stripe_head_list,
2216 					     struct ec_stripe_head, list);
2217 		if (h)
2218 			list_del(&h->list);
2219 		mutex_unlock(&c->ec_stripe_head_lock);
2220 		if (!h)
2221 			break;
2222 
2223 		if (h->s) {
2224 			for (i = 0; i < bkey_i_to_stripe(&h->s->new_stripe.key)->v.nr_blocks; i++)
2225 				BUG_ON(h->s->blocks[i]);
2226 
2227 			kfree(h->s);
2228 		}
2229 		kfree(h);
2230 	}
2231 
2232 	BUG_ON(!list_empty(&c->ec_stripe_new_list));
2233 
2234 	free_heap(&c->ec_stripes_heap);
2235 	genradix_free(&c->stripes);
2236 	bioset_exit(&c->ec_bioset);
2237 }
2238 
2239 void bch2_fs_ec_init_early(struct bch_fs *c)
2240 {
2241 	spin_lock_init(&c->ec_stripes_new_lock);
2242 	mutex_init(&c->ec_stripes_heap_lock);
2243 
2244 	INIT_LIST_HEAD(&c->ec_stripe_head_list);
2245 	mutex_init(&c->ec_stripe_head_lock);
2246 
2247 	INIT_LIST_HEAD(&c->ec_stripe_new_list);
2248 	mutex_init(&c->ec_stripe_new_lock);
2249 	init_waitqueue_head(&c->ec_stripe_new_wait);
2250 
2251 	INIT_WORK(&c->ec_stripe_create_work, ec_stripe_create_work);
2252 	INIT_WORK(&c->ec_stripe_delete_work, ec_stripe_delete_work);
2253 }
2254 
2255 int bch2_fs_ec_init(struct bch_fs *c)
2256 {
2257 	return bioset_init(&c->ec_bioset, 1, offsetof(struct ec_bio, bio),
2258 			   BIOSET_NEED_BVECS);
2259 }
2260