xref: /openbmc/linux/fs/btrfs/qgroup.c (revision cd238eff)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2011 STRATO.  All rights reserved.
4  */
5 
6 #include <linux/sched.h>
7 #include <linux/pagemap.h>
8 #include <linux/writeback.h>
9 #include <linux/blkdev.h>
10 #include <linux/rbtree.h>
11 #include <linux/slab.h>
12 #include <linux/workqueue.h>
13 #include <linux/btrfs.h>
14 #include <linux/sizes.h>
15 
16 #include "ctree.h"
17 #include "transaction.h"
18 #include "disk-io.h"
19 #include "locking.h"
20 #include "ulist.h"
21 #include "backref.h"
22 #include "extent_io.h"
23 #include "qgroup.h"
24 
25 
26 /* TODO XXX FIXME
27  *  - subvol delete -> delete when ref goes to 0? delete limits also?
28  *  - reorganize keys
29  *  - compressed
30  *  - sync
31  *  - copy also limits on subvol creation
32  *  - limit
33  *  - caches for ulists
34  *  - performance benchmarks
35  *  - check all ioctl parameters
36  */
37 
38 /*
39  * Helpers to access qgroup reservation
40  *
41  * Callers should ensure the lock context and type are valid
42  */
43 
44 static u64 qgroup_rsv_total(const struct btrfs_qgroup *qgroup)
45 {
46 	u64 ret = 0;
47 	int i;
48 
49 	for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
50 		ret += qgroup->rsv.values[i];
51 
52 	return ret;
53 }
54 
55 #ifdef CONFIG_BTRFS_DEBUG
56 static const char *qgroup_rsv_type_str(enum btrfs_qgroup_rsv_type type)
57 {
58 	if (type == BTRFS_QGROUP_RSV_DATA)
59 		return "data";
60 	if (type == BTRFS_QGROUP_RSV_META_PERTRANS)
61 		return "meta_pertrans";
62 	if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
63 		return "meta_prealloc";
64 	return NULL;
65 }
66 #endif
67 
68 static void qgroup_rsv_add(struct btrfs_fs_info *fs_info,
69 			   struct btrfs_qgroup *qgroup, u64 num_bytes,
70 			   enum btrfs_qgroup_rsv_type type)
71 {
72 	trace_qgroup_update_reserve(fs_info, qgroup, num_bytes, type);
73 	qgroup->rsv.values[type] += num_bytes;
74 }
75 
76 static void qgroup_rsv_release(struct btrfs_fs_info *fs_info,
77 			       struct btrfs_qgroup *qgroup, u64 num_bytes,
78 			       enum btrfs_qgroup_rsv_type type)
79 {
80 	trace_qgroup_update_reserve(fs_info, qgroup, -(s64)num_bytes, type);
81 	if (qgroup->rsv.values[type] >= num_bytes) {
82 		qgroup->rsv.values[type] -= num_bytes;
83 		return;
84 	}
85 #ifdef CONFIG_BTRFS_DEBUG
86 	WARN_RATELIMIT(1,
87 		"qgroup %llu %s reserved space underflow, have %llu to free %llu",
88 		qgroup->qgroupid, qgroup_rsv_type_str(type),
89 		qgroup->rsv.values[type], num_bytes);
90 #endif
91 	qgroup->rsv.values[type] = 0;
92 }
93 
94 static void qgroup_rsv_add_by_qgroup(struct btrfs_fs_info *fs_info,
95 				     struct btrfs_qgroup *dest,
96 				     struct btrfs_qgroup *src)
97 {
98 	int i;
99 
100 	for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
101 		qgroup_rsv_add(fs_info, dest, src->rsv.values[i], i);
102 }
103 
104 static void qgroup_rsv_release_by_qgroup(struct btrfs_fs_info *fs_info,
105 					 struct btrfs_qgroup *dest,
106 					  struct btrfs_qgroup *src)
107 {
108 	int i;
109 
110 	for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
111 		qgroup_rsv_release(fs_info, dest, src->rsv.values[i], i);
112 }
113 
114 static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,
115 					   int mod)
116 {
117 	if (qg->old_refcnt < seq)
118 		qg->old_refcnt = seq;
119 	qg->old_refcnt += mod;
120 }
121 
122 static void btrfs_qgroup_update_new_refcnt(struct btrfs_qgroup *qg, u64 seq,
123 					   int mod)
124 {
125 	if (qg->new_refcnt < seq)
126 		qg->new_refcnt = seq;
127 	qg->new_refcnt += mod;
128 }
129 
130 static inline u64 btrfs_qgroup_get_old_refcnt(struct btrfs_qgroup *qg, u64 seq)
131 {
132 	if (qg->old_refcnt < seq)
133 		return 0;
134 	return qg->old_refcnt - seq;
135 }
136 
137 static inline u64 btrfs_qgroup_get_new_refcnt(struct btrfs_qgroup *qg, u64 seq)
138 {
139 	if (qg->new_refcnt < seq)
140 		return 0;
141 	return qg->new_refcnt - seq;
142 }
143 
144 /*
145  * glue structure to represent the relations between qgroups.
146  */
147 struct btrfs_qgroup_list {
148 	struct list_head next_group;
149 	struct list_head next_member;
150 	struct btrfs_qgroup *group;
151 	struct btrfs_qgroup *member;
152 };
153 
154 static inline u64 qgroup_to_aux(struct btrfs_qgroup *qg)
155 {
156 	return (u64)(uintptr_t)qg;
157 }
158 
159 static inline struct btrfs_qgroup* unode_aux_to_qgroup(struct ulist_node *n)
160 {
161 	return (struct btrfs_qgroup *)(uintptr_t)n->aux;
162 }
163 
164 static int
165 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
166 		   int init_flags);
167 static void qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info);
168 
169 /* must be called with qgroup_ioctl_lock held */
170 static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
171 					   u64 qgroupid)
172 {
173 	struct rb_node *n = fs_info->qgroup_tree.rb_node;
174 	struct btrfs_qgroup *qgroup;
175 
176 	while (n) {
177 		qgroup = rb_entry(n, struct btrfs_qgroup, node);
178 		if (qgroup->qgroupid < qgroupid)
179 			n = n->rb_left;
180 		else if (qgroup->qgroupid > qgroupid)
181 			n = n->rb_right;
182 		else
183 			return qgroup;
184 	}
185 	return NULL;
186 }
187 
188 /* must be called with qgroup_lock held */
189 static struct btrfs_qgroup *add_qgroup_rb(struct btrfs_fs_info *fs_info,
190 					  u64 qgroupid)
191 {
192 	struct rb_node **p = &fs_info->qgroup_tree.rb_node;
193 	struct rb_node *parent = NULL;
194 	struct btrfs_qgroup *qgroup;
195 
196 	while (*p) {
197 		parent = *p;
198 		qgroup = rb_entry(parent, struct btrfs_qgroup, node);
199 
200 		if (qgroup->qgroupid < qgroupid)
201 			p = &(*p)->rb_left;
202 		else if (qgroup->qgroupid > qgroupid)
203 			p = &(*p)->rb_right;
204 		else
205 			return qgroup;
206 	}
207 
208 	qgroup = kzalloc(sizeof(*qgroup), GFP_ATOMIC);
209 	if (!qgroup)
210 		return ERR_PTR(-ENOMEM);
211 
212 	qgroup->qgroupid = qgroupid;
213 	INIT_LIST_HEAD(&qgroup->groups);
214 	INIT_LIST_HEAD(&qgroup->members);
215 	INIT_LIST_HEAD(&qgroup->dirty);
216 
217 	rb_link_node(&qgroup->node, parent, p);
218 	rb_insert_color(&qgroup->node, &fs_info->qgroup_tree);
219 
220 	return qgroup;
221 }
222 
223 static void __del_qgroup_rb(struct btrfs_qgroup *qgroup)
224 {
225 	struct btrfs_qgroup_list *list;
226 
227 	list_del(&qgroup->dirty);
228 	while (!list_empty(&qgroup->groups)) {
229 		list = list_first_entry(&qgroup->groups,
230 					struct btrfs_qgroup_list, next_group);
231 		list_del(&list->next_group);
232 		list_del(&list->next_member);
233 		kfree(list);
234 	}
235 
236 	while (!list_empty(&qgroup->members)) {
237 		list = list_first_entry(&qgroup->members,
238 					struct btrfs_qgroup_list, next_member);
239 		list_del(&list->next_group);
240 		list_del(&list->next_member);
241 		kfree(list);
242 	}
243 	kfree(qgroup);
244 }
245 
246 /* must be called with qgroup_lock held */
247 static int del_qgroup_rb(struct btrfs_fs_info *fs_info, u64 qgroupid)
248 {
249 	struct btrfs_qgroup *qgroup = find_qgroup_rb(fs_info, qgroupid);
250 
251 	if (!qgroup)
252 		return -ENOENT;
253 
254 	rb_erase(&qgroup->node, &fs_info->qgroup_tree);
255 	__del_qgroup_rb(qgroup);
256 	return 0;
257 }
258 
259 /* must be called with qgroup_lock held */
260 static int add_relation_rb(struct btrfs_fs_info *fs_info,
261 			   u64 memberid, u64 parentid)
262 {
263 	struct btrfs_qgroup *member;
264 	struct btrfs_qgroup *parent;
265 	struct btrfs_qgroup_list *list;
266 
267 	member = find_qgroup_rb(fs_info, memberid);
268 	parent = find_qgroup_rb(fs_info, parentid);
269 	if (!member || !parent)
270 		return -ENOENT;
271 
272 	list = kzalloc(sizeof(*list), GFP_ATOMIC);
273 	if (!list)
274 		return -ENOMEM;
275 
276 	list->group = parent;
277 	list->member = member;
278 	list_add_tail(&list->next_group, &member->groups);
279 	list_add_tail(&list->next_member, &parent->members);
280 
281 	return 0;
282 }
283 
284 /* must be called with qgroup_lock held */
285 static int del_relation_rb(struct btrfs_fs_info *fs_info,
286 			   u64 memberid, u64 parentid)
287 {
288 	struct btrfs_qgroup *member;
289 	struct btrfs_qgroup *parent;
290 	struct btrfs_qgroup_list *list;
291 
292 	member = find_qgroup_rb(fs_info, memberid);
293 	parent = find_qgroup_rb(fs_info, parentid);
294 	if (!member || !parent)
295 		return -ENOENT;
296 
297 	list_for_each_entry(list, &member->groups, next_group) {
298 		if (list->group == parent) {
299 			list_del(&list->next_group);
300 			list_del(&list->next_member);
301 			kfree(list);
302 			return 0;
303 		}
304 	}
305 	return -ENOENT;
306 }
307 
308 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
309 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
310 			       u64 rfer, u64 excl)
311 {
312 	struct btrfs_qgroup *qgroup;
313 
314 	qgroup = find_qgroup_rb(fs_info, qgroupid);
315 	if (!qgroup)
316 		return -EINVAL;
317 	if (qgroup->rfer != rfer || qgroup->excl != excl)
318 		return -EINVAL;
319 	return 0;
320 }
321 #endif
322 
323 /*
324  * The full config is read in one go, only called from open_ctree()
325  * It doesn't use any locking, as at this point we're still single-threaded
326  */
327 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
328 {
329 	struct btrfs_key key;
330 	struct btrfs_key found_key;
331 	struct btrfs_root *quota_root = fs_info->quota_root;
332 	struct btrfs_path *path = NULL;
333 	struct extent_buffer *l;
334 	int slot;
335 	int ret = 0;
336 	u64 flags = 0;
337 	u64 rescan_progress = 0;
338 
339 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
340 		return 0;
341 
342 	fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
343 	if (!fs_info->qgroup_ulist) {
344 		ret = -ENOMEM;
345 		goto out;
346 	}
347 
348 	path = btrfs_alloc_path();
349 	if (!path) {
350 		ret = -ENOMEM;
351 		goto out;
352 	}
353 
354 	/* default this to quota off, in case no status key is found */
355 	fs_info->qgroup_flags = 0;
356 
357 	/*
358 	 * pass 1: read status, all qgroup infos and limits
359 	 */
360 	key.objectid = 0;
361 	key.type = 0;
362 	key.offset = 0;
363 	ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 1);
364 	if (ret)
365 		goto out;
366 
367 	while (1) {
368 		struct btrfs_qgroup *qgroup;
369 
370 		slot = path->slots[0];
371 		l = path->nodes[0];
372 		btrfs_item_key_to_cpu(l, &found_key, slot);
373 
374 		if (found_key.type == BTRFS_QGROUP_STATUS_KEY) {
375 			struct btrfs_qgroup_status_item *ptr;
376 
377 			ptr = btrfs_item_ptr(l, slot,
378 					     struct btrfs_qgroup_status_item);
379 
380 			if (btrfs_qgroup_status_version(l, ptr) !=
381 			    BTRFS_QGROUP_STATUS_VERSION) {
382 				btrfs_err(fs_info,
383 				 "old qgroup version, quota disabled");
384 				goto out;
385 			}
386 			if (btrfs_qgroup_status_generation(l, ptr) !=
387 			    fs_info->generation) {
388 				flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
389 				btrfs_err(fs_info,
390 					"qgroup generation mismatch, marked as inconsistent");
391 			}
392 			fs_info->qgroup_flags = btrfs_qgroup_status_flags(l,
393 									  ptr);
394 			rescan_progress = btrfs_qgroup_status_rescan(l, ptr);
395 			goto next1;
396 		}
397 
398 		if (found_key.type != BTRFS_QGROUP_INFO_KEY &&
399 		    found_key.type != BTRFS_QGROUP_LIMIT_KEY)
400 			goto next1;
401 
402 		qgroup = find_qgroup_rb(fs_info, found_key.offset);
403 		if ((qgroup && found_key.type == BTRFS_QGROUP_INFO_KEY) ||
404 		    (!qgroup && found_key.type == BTRFS_QGROUP_LIMIT_KEY)) {
405 			btrfs_err(fs_info, "inconsistent qgroup config");
406 			flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
407 		}
408 		if (!qgroup) {
409 			qgroup = add_qgroup_rb(fs_info, found_key.offset);
410 			if (IS_ERR(qgroup)) {
411 				ret = PTR_ERR(qgroup);
412 				goto out;
413 			}
414 		}
415 		switch (found_key.type) {
416 		case BTRFS_QGROUP_INFO_KEY: {
417 			struct btrfs_qgroup_info_item *ptr;
418 
419 			ptr = btrfs_item_ptr(l, slot,
420 					     struct btrfs_qgroup_info_item);
421 			qgroup->rfer = btrfs_qgroup_info_rfer(l, ptr);
422 			qgroup->rfer_cmpr = btrfs_qgroup_info_rfer_cmpr(l, ptr);
423 			qgroup->excl = btrfs_qgroup_info_excl(l, ptr);
424 			qgroup->excl_cmpr = btrfs_qgroup_info_excl_cmpr(l, ptr);
425 			/* generation currently unused */
426 			break;
427 		}
428 		case BTRFS_QGROUP_LIMIT_KEY: {
429 			struct btrfs_qgroup_limit_item *ptr;
430 
431 			ptr = btrfs_item_ptr(l, slot,
432 					     struct btrfs_qgroup_limit_item);
433 			qgroup->lim_flags = btrfs_qgroup_limit_flags(l, ptr);
434 			qgroup->max_rfer = btrfs_qgroup_limit_max_rfer(l, ptr);
435 			qgroup->max_excl = btrfs_qgroup_limit_max_excl(l, ptr);
436 			qgroup->rsv_rfer = btrfs_qgroup_limit_rsv_rfer(l, ptr);
437 			qgroup->rsv_excl = btrfs_qgroup_limit_rsv_excl(l, ptr);
438 			break;
439 		}
440 		}
441 next1:
442 		ret = btrfs_next_item(quota_root, path);
443 		if (ret < 0)
444 			goto out;
445 		if (ret)
446 			break;
447 	}
448 	btrfs_release_path(path);
449 
450 	/*
451 	 * pass 2: read all qgroup relations
452 	 */
453 	key.objectid = 0;
454 	key.type = BTRFS_QGROUP_RELATION_KEY;
455 	key.offset = 0;
456 	ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 0);
457 	if (ret)
458 		goto out;
459 	while (1) {
460 		slot = path->slots[0];
461 		l = path->nodes[0];
462 		btrfs_item_key_to_cpu(l, &found_key, slot);
463 
464 		if (found_key.type != BTRFS_QGROUP_RELATION_KEY)
465 			goto next2;
466 
467 		if (found_key.objectid > found_key.offset) {
468 			/* parent <- member, not needed to build config */
469 			/* FIXME should we omit the key completely? */
470 			goto next2;
471 		}
472 
473 		ret = add_relation_rb(fs_info, found_key.objectid,
474 				      found_key.offset);
475 		if (ret == -ENOENT) {
476 			btrfs_warn(fs_info,
477 				"orphan qgroup relation 0x%llx->0x%llx",
478 				found_key.objectid, found_key.offset);
479 			ret = 0;	/* ignore the error */
480 		}
481 		if (ret)
482 			goto out;
483 next2:
484 		ret = btrfs_next_item(quota_root, path);
485 		if (ret < 0)
486 			goto out;
487 		if (ret)
488 			break;
489 	}
490 out:
491 	fs_info->qgroup_flags |= flags;
492 	if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON))
493 		clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
494 	else if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN &&
495 		 ret >= 0)
496 		ret = qgroup_rescan_init(fs_info, rescan_progress, 0);
497 	btrfs_free_path(path);
498 
499 	if (ret < 0) {
500 		ulist_free(fs_info->qgroup_ulist);
501 		fs_info->qgroup_ulist = NULL;
502 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
503 	}
504 
505 	return ret < 0 ? ret : 0;
506 }
507 
508 /*
509  * This is called from close_ctree() or open_ctree() or btrfs_quota_disable(),
510  * first two are in single-threaded paths.And for the third one, we have set
511  * quota_root to be null with qgroup_lock held before, so it is safe to clean
512  * up the in-memory structures without qgroup_lock held.
513  */
514 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
515 {
516 	struct rb_node *n;
517 	struct btrfs_qgroup *qgroup;
518 
519 	while ((n = rb_first(&fs_info->qgroup_tree))) {
520 		qgroup = rb_entry(n, struct btrfs_qgroup, node);
521 		rb_erase(n, &fs_info->qgroup_tree);
522 		__del_qgroup_rb(qgroup);
523 	}
524 	/*
525 	 * We call btrfs_free_qgroup_config() when unmounting
526 	 * filesystem and disabling quota, so we set qgroup_ulist
527 	 * to be null here to avoid double free.
528 	 */
529 	ulist_free(fs_info->qgroup_ulist);
530 	fs_info->qgroup_ulist = NULL;
531 }
532 
533 static int add_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
534 				    u64 dst)
535 {
536 	int ret;
537 	struct btrfs_root *quota_root = trans->fs_info->quota_root;
538 	struct btrfs_path *path;
539 	struct btrfs_key key;
540 
541 	path = btrfs_alloc_path();
542 	if (!path)
543 		return -ENOMEM;
544 
545 	key.objectid = src;
546 	key.type = BTRFS_QGROUP_RELATION_KEY;
547 	key.offset = dst;
548 
549 	ret = btrfs_insert_empty_item(trans, quota_root, path, &key, 0);
550 
551 	btrfs_mark_buffer_dirty(path->nodes[0]);
552 
553 	btrfs_free_path(path);
554 	return ret;
555 }
556 
557 static int del_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
558 				    u64 dst)
559 {
560 	int ret;
561 	struct btrfs_root *quota_root = trans->fs_info->quota_root;
562 	struct btrfs_path *path;
563 	struct btrfs_key key;
564 
565 	path = btrfs_alloc_path();
566 	if (!path)
567 		return -ENOMEM;
568 
569 	key.objectid = src;
570 	key.type = BTRFS_QGROUP_RELATION_KEY;
571 	key.offset = dst;
572 
573 	ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
574 	if (ret < 0)
575 		goto out;
576 
577 	if (ret > 0) {
578 		ret = -ENOENT;
579 		goto out;
580 	}
581 
582 	ret = btrfs_del_item(trans, quota_root, path);
583 out:
584 	btrfs_free_path(path);
585 	return ret;
586 }
587 
588 static int add_qgroup_item(struct btrfs_trans_handle *trans,
589 			   struct btrfs_root *quota_root, u64 qgroupid)
590 {
591 	int ret;
592 	struct btrfs_path *path;
593 	struct btrfs_qgroup_info_item *qgroup_info;
594 	struct btrfs_qgroup_limit_item *qgroup_limit;
595 	struct extent_buffer *leaf;
596 	struct btrfs_key key;
597 
598 	if (btrfs_is_testing(quota_root->fs_info))
599 		return 0;
600 
601 	path = btrfs_alloc_path();
602 	if (!path)
603 		return -ENOMEM;
604 
605 	key.objectid = 0;
606 	key.type = BTRFS_QGROUP_INFO_KEY;
607 	key.offset = qgroupid;
608 
609 	/*
610 	 * Avoid a transaction abort by catching -EEXIST here. In that
611 	 * case, we proceed by re-initializing the existing structure
612 	 * on disk.
613 	 */
614 
615 	ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
616 				      sizeof(*qgroup_info));
617 	if (ret && ret != -EEXIST)
618 		goto out;
619 
620 	leaf = path->nodes[0];
621 	qgroup_info = btrfs_item_ptr(leaf, path->slots[0],
622 				 struct btrfs_qgroup_info_item);
623 	btrfs_set_qgroup_info_generation(leaf, qgroup_info, trans->transid);
624 	btrfs_set_qgroup_info_rfer(leaf, qgroup_info, 0);
625 	btrfs_set_qgroup_info_rfer_cmpr(leaf, qgroup_info, 0);
626 	btrfs_set_qgroup_info_excl(leaf, qgroup_info, 0);
627 	btrfs_set_qgroup_info_excl_cmpr(leaf, qgroup_info, 0);
628 
629 	btrfs_mark_buffer_dirty(leaf);
630 
631 	btrfs_release_path(path);
632 
633 	key.type = BTRFS_QGROUP_LIMIT_KEY;
634 	ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
635 				      sizeof(*qgroup_limit));
636 	if (ret && ret != -EEXIST)
637 		goto out;
638 
639 	leaf = path->nodes[0];
640 	qgroup_limit = btrfs_item_ptr(leaf, path->slots[0],
641 				  struct btrfs_qgroup_limit_item);
642 	btrfs_set_qgroup_limit_flags(leaf, qgroup_limit, 0);
643 	btrfs_set_qgroup_limit_max_rfer(leaf, qgroup_limit, 0);
644 	btrfs_set_qgroup_limit_max_excl(leaf, qgroup_limit, 0);
645 	btrfs_set_qgroup_limit_rsv_rfer(leaf, qgroup_limit, 0);
646 	btrfs_set_qgroup_limit_rsv_excl(leaf, qgroup_limit, 0);
647 
648 	btrfs_mark_buffer_dirty(leaf);
649 
650 	ret = 0;
651 out:
652 	btrfs_free_path(path);
653 	return ret;
654 }
655 
656 static int del_qgroup_item(struct btrfs_trans_handle *trans, u64 qgroupid)
657 {
658 	int ret;
659 	struct btrfs_root *quota_root = trans->fs_info->quota_root;
660 	struct btrfs_path *path;
661 	struct btrfs_key key;
662 
663 	path = btrfs_alloc_path();
664 	if (!path)
665 		return -ENOMEM;
666 
667 	key.objectid = 0;
668 	key.type = BTRFS_QGROUP_INFO_KEY;
669 	key.offset = qgroupid;
670 	ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
671 	if (ret < 0)
672 		goto out;
673 
674 	if (ret > 0) {
675 		ret = -ENOENT;
676 		goto out;
677 	}
678 
679 	ret = btrfs_del_item(trans, quota_root, path);
680 	if (ret)
681 		goto out;
682 
683 	btrfs_release_path(path);
684 
685 	key.type = BTRFS_QGROUP_LIMIT_KEY;
686 	ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
687 	if (ret < 0)
688 		goto out;
689 
690 	if (ret > 0) {
691 		ret = -ENOENT;
692 		goto out;
693 	}
694 
695 	ret = btrfs_del_item(trans, quota_root, path);
696 
697 out:
698 	btrfs_free_path(path);
699 	return ret;
700 }
701 
702 static int update_qgroup_limit_item(struct btrfs_trans_handle *trans,
703 				    struct btrfs_qgroup *qgroup)
704 {
705 	struct btrfs_root *quota_root = trans->fs_info->quota_root;
706 	struct btrfs_path *path;
707 	struct btrfs_key key;
708 	struct extent_buffer *l;
709 	struct btrfs_qgroup_limit_item *qgroup_limit;
710 	int ret;
711 	int slot;
712 
713 	key.objectid = 0;
714 	key.type = BTRFS_QGROUP_LIMIT_KEY;
715 	key.offset = qgroup->qgroupid;
716 
717 	path = btrfs_alloc_path();
718 	if (!path)
719 		return -ENOMEM;
720 
721 	ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
722 	if (ret > 0)
723 		ret = -ENOENT;
724 
725 	if (ret)
726 		goto out;
727 
728 	l = path->nodes[0];
729 	slot = path->slots[0];
730 	qgroup_limit = btrfs_item_ptr(l, slot, struct btrfs_qgroup_limit_item);
731 	btrfs_set_qgroup_limit_flags(l, qgroup_limit, qgroup->lim_flags);
732 	btrfs_set_qgroup_limit_max_rfer(l, qgroup_limit, qgroup->max_rfer);
733 	btrfs_set_qgroup_limit_max_excl(l, qgroup_limit, qgroup->max_excl);
734 	btrfs_set_qgroup_limit_rsv_rfer(l, qgroup_limit, qgroup->rsv_rfer);
735 	btrfs_set_qgroup_limit_rsv_excl(l, qgroup_limit, qgroup->rsv_excl);
736 
737 	btrfs_mark_buffer_dirty(l);
738 
739 out:
740 	btrfs_free_path(path);
741 	return ret;
742 }
743 
744 static int update_qgroup_info_item(struct btrfs_trans_handle *trans,
745 				   struct btrfs_qgroup *qgroup)
746 {
747 	struct btrfs_fs_info *fs_info = trans->fs_info;
748 	struct btrfs_root *quota_root = fs_info->quota_root;
749 	struct btrfs_path *path;
750 	struct btrfs_key key;
751 	struct extent_buffer *l;
752 	struct btrfs_qgroup_info_item *qgroup_info;
753 	int ret;
754 	int slot;
755 
756 	if (btrfs_is_testing(fs_info))
757 		return 0;
758 
759 	key.objectid = 0;
760 	key.type = BTRFS_QGROUP_INFO_KEY;
761 	key.offset = qgroup->qgroupid;
762 
763 	path = btrfs_alloc_path();
764 	if (!path)
765 		return -ENOMEM;
766 
767 	ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
768 	if (ret > 0)
769 		ret = -ENOENT;
770 
771 	if (ret)
772 		goto out;
773 
774 	l = path->nodes[0];
775 	slot = path->slots[0];
776 	qgroup_info = btrfs_item_ptr(l, slot, struct btrfs_qgroup_info_item);
777 	btrfs_set_qgroup_info_generation(l, qgroup_info, trans->transid);
778 	btrfs_set_qgroup_info_rfer(l, qgroup_info, qgroup->rfer);
779 	btrfs_set_qgroup_info_rfer_cmpr(l, qgroup_info, qgroup->rfer_cmpr);
780 	btrfs_set_qgroup_info_excl(l, qgroup_info, qgroup->excl);
781 	btrfs_set_qgroup_info_excl_cmpr(l, qgroup_info, qgroup->excl_cmpr);
782 
783 	btrfs_mark_buffer_dirty(l);
784 
785 out:
786 	btrfs_free_path(path);
787 	return ret;
788 }
789 
790 static int update_qgroup_status_item(struct btrfs_trans_handle *trans)
791 {
792 	struct btrfs_fs_info *fs_info = trans->fs_info;
793 	struct btrfs_root *quota_root = fs_info->quota_root;
794 	struct btrfs_path *path;
795 	struct btrfs_key key;
796 	struct extent_buffer *l;
797 	struct btrfs_qgroup_status_item *ptr;
798 	int ret;
799 	int slot;
800 
801 	key.objectid = 0;
802 	key.type = BTRFS_QGROUP_STATUS_KEY;
803 	key.offset = 0;
804 
805 	path = btrfs_alloc_path();
806 	if (!path)
807 		return -ENOMEM;
808 
809 	ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
810 	if (ret > 0)
811 		ret = -ENOENT;
812 
813 	if (ret)
814 		goto out;
815 
816 	l = path->nodes[0];
817 	slot = path->slots[0];
818 	ptr = btrfs_item_ptr(l, slot, struct btrfs_qgroup_status_item);
819 	btrfs_set_qgroup_status_flags(l, ptr, fs_info->qgroup_flags);
820 	btrfs_set_qgroup_status_generation(l, ptr, trans->transid);
821 	btrfs_set_qgroup_status_rescan(l, ptr,
822 				fs_info->qgroup_rescan_progress.objectid);
823 
824 	btrfs_mark_buffer_dirty(l);
825 
826 out:
827 	btrfs_free_path(path);
828 	return ret;
829 }
830 
831 /*
832  * called with qgroup_lock held
833  */
834 static int btrfs_clean_quota_tree(struct btrfs_trans_handle *trans,
835 				  struct btrfs_root *root)
836 {
837 	struct btrfs_path *path;
838 	struct btrfs_key key;
839 	struct extent_buffer *leaf = NULL;
840 	int ret;
841 	int nr = 0;
842 
843 	path = btrfs_alloc_path();
844 	if (!path)
845 		return -ENOMEM;
846 
847 	path->leave_spinning = 1;
848 
849 	key.objectid = 0;
850 	key.offset = 0;
851 	key.type = 0;
852 
853 	while (1) {
854 		ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
855 		if (ret < 0)
856 			goto out;
857 		leaf = path->nodes[0];
858 		nr = btrfs_header_nritems(leaf);
859 		if (!nr)
860 			break;
861 		/*
862 		 * delete the leaf one by one
863 		 * since the whole tree is going
864 		 * to be deleted.
865 		 */
866 		path->slots[0] = 0;
867 		ret = btrfs_del_items(trans, root, path, 0, nr);
868 		if (ret)
869 			goto out;
870 
871 		btrfs_release_path(path);
872 	}
873 	ret = 0;
874 out:
875 	btrfs_free_path(path);
876 	return ret;
877 }
878 
879 int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
880 {
881 	struct btrfs_root *quota_root;
882 	struct btrfs_root *tree_root = fs_info->tree_root;
883 	struct btrfs_path *path = NULL;
884 	struct btrfs_qgroup_status_item *ptr;
885 	struct extent_buffer *leaf;
886 	struct btrfs_key key;
887 	struct btrfs_key found_key;
888 	struct btrfs_qgroup *qgroup = NULL;
889 	struct btrfs_trans_handle *trans = NULL;
890 	int ret = 0;
891 	int slot;
892 
893 	mutex_lock(&fs_info->qgroup_ioctl_lock);
894 	if (fs_info->quota_root)
895 		goto out;
896 
897 	fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
898 	if (!fs_info->qgroup_ulist) {
899 		ret = -ENOMEM;
900 		goto out;
901 	}
902 
903 	/*
904 	 * 1 for quota root item
905 	 * 1 for BTRFS_QGROUP_STATUS item
906 	 *
907 	 * Yet we also need 2*n items for a QGROUP_INFO/QGROUP_LIMIT items
908 	 * per subvolume. However those are not currently reserved since it
909 	 * would be a lot of overkill.
910 	 */
911 	trans = btrfs_start_transaction(tree_root, 2);
912 	if (IS_ERR(trans)) {
913 		ret = PTR_ERR(trans);
914 		trans = NULL;
915 		goto out;
916 	}
917 
918 	/*
919 	 * initially create the quota tree
920 	 */
921 	quota_root = btrfs_create_tree(trans, BTRFS_QUOTA_TREE_OBJECTID);
922 	if (IS_ERR(quota_root)) {
923 		ret =  PTR_ERR(quota_root);
924 		btrfs_abort_transaction(trans, ret);
925 		goto out;
926 	}
927 
928 	path = btrfs_alloc_path();
929 	if (!path) {
930 		ret = -ENOMEM;
931 		btrfs_abort_transaction(trans, ret);
932 		goto out_free_root;
933 	}
934 
935 	key.objectid = 0;
936 	key.type = BTRFS_QGROUP_STATUS_KEY;
937 	key.offset = 0;
938 
939 	ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
940 				      sizeof(*ptr));
941 	if (ret) {
942 		btrfs_abort_transaction(trans, ret);
943 		goto out_free_path;
944 	}
945 
946 	leaf = path->nodes[0];
947 	ptr = btrfs_item_ptr(leaf, path->slots[0],
948 				 struct btrfs_qgroup_status_item);
949 	btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
950 	btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
951 	fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON |
952 				BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
953 	btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags);
954 	btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
955 
956 	btrfs_mark_buffer_dirty(leaf);
957 
958 	key.objectid = 0;
959 	key.type = BTRFS_ROOT_REF_KEY;
960 	key.offset = 0;
961 
962 	btrfs_release_path(path);
963 	ret = btrfs_search_slot_for_read(tree_root, &key, path, 1, 0);
964 	if (ret > 0)
965 		goto out_add_root;
966 	if (ret < 0) {
967 		btrfs_abort_transaction(trans, ret);
968 		goto out_free_path;
969 	}
970 
971 	while (1) {
972 		slot = path->slots[0];
973 		leaf = path->nodes[0];
974 		btrfs_item_key_to_cpu(leaf, &found_key, slot);
975 
976 		if (found_key.type == BTRFS_ROOT_REF_KEY) {
977 			ret = add_qgroup_item(trans, quota_root,
978 					      found_key.offset);
979 			if (ret) {
980 				btrfs_abort_transaction(trans, ret);
981 				goto out_free_path;
982 			}
983 
984 			qgroup = add_qgroup_rb(fs_info, found_key.offset);
985 			if (IS_ERR(qgroup)) {
986 				ret = PTR_ERR(qgroup);
987 				btrfs_abort_transaction(trans, ret);
988 				goto out_free_path;
989 			}
990 		}
991 		ret = btrfs_next_item(tree_root, path);
992 		if (ret < 0) {
993 			btrfs_abort_transaction(trans, ret);
994 			goto out_free_path;
995 		}
996 		if (ret)
997 			break;
998 	}
999 
1000 out_add_root:
1001 	btrfs_release_path(path);
1002 	ret = add_qgroup_item(trans, quota_root, BTRFS_FS_TREE_OBJECTID);
1003 	if (ret) {
1004 		btrfs_abort_transaction(trans, ret);
1005 		goto out_free_path;
1006 	}
1007 
1008 	qgroup = add_qgroup_rb(fs_info, BTRFS_FS_TREE_OBJECTID);
1009 	if (IS_ERR(qgroup)) {
1010 		ret = PTR_ERR(qgroup);
1011 		btrfs_abort_transaction(trans, ret);
1012 		goto out_free_path;
1013 	}
1014 
1015 	ret = btrfs_commit_transaction(trans);
1016 	trans = NULL;
1017 	if (ret)
1018 		goto out_free_path;
1019 
1020 	/*
1021 	 * Set quota enabled flag after committing the transaction, to avoid
1022 	 * deadlocks on fs_info->qgroup_ioctl_lock with concurrent snapshot
1023 	 * creation.
1024 	 */
1025 	spin_lock(&fs_info->qgroup_lock);
1026 	fs_info->quota_root = quota_root;
1027 	set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1028 	spin_unlock(&fs_info->qgroup_lock);
1029 
1030 	ret = qgroup_rescan_init(fs_info, 0, 1);
1031 	if (!ret) {
1032 	        qgroup_rescan_zero_tracking(fs_info);
1033 	        btrfs_queue_work(fs_info->qgroup_rescan_workers,
1034 	                         &fs_info->qgroup_rescan_work);
1035 	}
1036 
1037 out_free_path:
1038 	btrfs_free_path(path);
1039 out_free_root:
1040 	if (ret) {
1041 		free_extent_buffer(quota_root->node);
1042 		free_extent_buffer(quota_root->commit_root);
1043 		kfree(quota_root);
1044 	}
1045 out:
1046 	if (ret) {
1047 		ulist_free(fs_info->qgroup_ulist);
1048 		fs_info->qgroup_ulist = NULL;
1049 		if (trans)
1050 			btrfs_end_transaction(trans);
1051 	}
1052 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1053 	return ret;
1054 }
1055 
1056 int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
1057 {
1058 	struct btrfs_root *quota_root;
1059 	struct btrfs_trans_handle *trans = NULL;
1060 	int ret = 0;
1061 
1062 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1063 	if (!fs_info->quota_root)
1064 		goto out;
1065 
1066 	/*
1067 	 * 1 For the root item
1068 	 *
1069 	 * We should also reserve enough items for the quota tree deletion in
1070 	 * btrfs_clean_quota_tree but this is not done.
1071 	 */
1072 	trans = btrfs_start_transaction(fs_info->tree_root, 1);
1073 	if (IS_ERR(trans)) {
1074 		ret = PTR_ERR(trans);
1075 		goto out;
1076 	}
1077 
1078 	clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1079 	btrfs_qgroup_wait_for_completion(fs_info, false);
1080 	spin_lock(&fs_info->qgroup_lock);
1081 	quota_root = fs_info->quota_root;
1082 	fs_info->quota_root = NULL;
1083 	fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
1084 	spin_unlock(&fs_info->qgroup_lock);
1085 
1086 	btrfs_free_qgroup_config(fs_info);
1087 
1088 	ret = btrfs_clean_quota_tree(trans, quota_root);
1089 	if (ret) {
1090 		btrfs_abort_transaction(trans, ret);
1091 		goto end_trans;
1092 	}
1093 
1094 	ret = btrfs_del_root(trans, &quota_root->root_key);
1095 	if (ret) {
1096 		btrfs_abort_transaction(trans, ret);
1097 		goto end_trans;
1098 	}
1099 
1100 	list_del(&quota_root->dirty_list);
1101 
1102 	btrfs_tree_lock(quota_root->node);
1103 	btrfs_clean_tree_block(quota_root->node);
1104 	btrfs_tree_unlock(quota_root->node);
1105 	btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1);
1106 
1107 	free_extent_buffer(quota_root->node);
1108 	free_extent_buffer(quota_root->commit_root);
1109 	kfree(quota_root);
1110 
1111 end_trans:
1112 	ret = btrfs_end_transaction(trans);
1113 out:
1114 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1115 	return ret;
1116 }
1117 
1118 static void qgroup_dirty(struct btrfs_fs_info *fs_info,
1119 			 struct btrfs_qgroup *qgroup)
1120 {
1121 	if (list_empty(&qgroup->dirty))
1122 		list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
1123 }
1124 
1125 /*
1126  * The easy accounting, we're updating qgroup relationship whose child qgroup
1127  * only has exclusive extents.
1128  *
1129  * In this case, all exclusive extents will also be exclusive for parent, so
1130  * excl/rfer just get added/removed.
1131  *
1132  * So is qgroup reservation space, which should also be added/removed to
1133  * parent.
1134  * Or when child tries to release reservation space, parent will underflow its
1135  * reservation (for relationship adding case).
1136  *
1137  * Caller should hold fs_info->qgroup_lock.
1138  */
1139 static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
1140 				    struct ulist *tmp, u64 ref_root,
1141 				    struct btrfs_qgroup *src, int sign)
1142 {
1143 	struct btrfs_qgroup *qgroup;
1144 	struct btrfs_qgroup_list *glist;
1145 	struct ulist_node *unode;
1146 	struct ulist_iterator uiter;
1147 	u64 num_bytes = src->excl;
1148 	int ret = 0;
1149 
1150 	qgroup = find_qgroup_rb(fs_info, ref_root);
1151 	if (!qgroup)
1152 		goto out;
1153 
1154 	qgroup->rfer += sign * num_bytes;
1155 	qgroup->rfer_cmpr += sign * num_bytes;
1156 
1157 	WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1158 	qgroup->excl += sign * num_bytes;
1159 	qgroup->excl_cmpr += sign * num_bytes;
1160 
1161 	if (sign > 0)
1162 		qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1163 	else
1164 		qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1165 
1166 	qgroup_dirty(fs_info, qgroup);
1167 
1168 	/* Get all of the parent groups that contain this qgroup */
1169 	list_for_each_entry(glist, &qgroup->groups, next_group) {
1170 		ret = ulist_add(tmp, glist->group->qgroupid,
1171 				qgroup_to_aux(glist->group), GFP_ATOMIC);
1172 		if (ret < 0)
1173 			goto out;
1174 	}
1175 
1176 	/* Iterate all of the parents and adjust their reference counts */
1177 	ULIST_ITER_INIT(&uiter);
1178 	while ((unode = ulist_next(tmp, &uiter))) {
1179 		qgroup = unode_aux_to_qgroup(unode);
1180 		qgroup->rfer += sign * num_bytes;
1181 		qgroup->rfer_cmpr += sign * num_bytes;
1182 		WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1183 		qgroup->excl += sign * num_bytes;
1184 		if (sign > 0)
1185 			qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1186 		else
1187 			qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1188 		qgroup->excl_cmpr += sign * num_bytes;
1189 		qgroup_dirty(fs_info, qgroup);
1190 
1191 		/* Add any parents of the parents */
1192 		list_for_each_entry(glist, &qgroup->groups, next_group) {
1193 			ret = ulist_add(tmp, glist->group->qgroupid,
1194 					qgroup_to_aux(glist->group), GFP_ATOMIC);
1195 			if (ret < 0)
1196 				goto out;
1197 		}
1198 	}
1199 	ret = 0;
1200 out:
1201 	return ret;
1202 }
1203 
1204 
1205 /*
1206  * Quick path for updating qgroup with only excl refs.
1207  *
1208  * In that case, just update all parent will be enough.
1209  * Or we needs to do a full rescan.
1210  * Caller should also hold fs_info->qgroup_lock.
1211  *
1212  * Return 0 for quick update, return >0 for need to full rescan
1213  * and mark INCONSISTENT flag.
1214  * Return < 0 for other error.
1215  */
1216 static int quick_update_accounting(struct btrfs_fs_info *fs_info,
1217 				   struct ulist *tmp, u64 src, u64 dst,
1218 				   int sign)
1219 {
1220 	struct btrfs_qgroup *qgroup;
1221 	int ret = 1;
1222 	int err = 0;
1223 
1224 	qgroup = find_qgroup_rb(fs_info, src);
1225 	if (!qgroup)
1226 		goto out;
1227 	if (qgroup->excl == qgroup->rfer) {
1228 		ret = 0;
1229 		err = __qgroup_excl_accounting(fs_info, tmp, dst,
1230 					       qgroup, sign);
1231 		if (err < 0) {
1232 			ret = err;
1233 			goto out;
1234 		}
1235 	}
1236 out:
1237 	if (ret)
1238 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1239 	return ret;
1240 }
1241 
1242 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1243 			      u64 dst)
1244 {
1245 	struct btrfs_fs_info *fs_info = trans->fs_info;
1246 	struct btrfs_root *quota_root;
1247 	struct btrfs_qgroup *parent;
1248 	struct btrfs_qgroup *member;
1249 	struct btrfs_qgroup_list *list;
1250 	struct ulist *tmp;
1251 	int ret = 0;
1252 
1253 	/* Check the level of src and dst first */
1254 	if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
1255 		return -EINVAL;
1256 
1257 	tmp = ulist_alloc(GFP_KERNEL);
1258 	if (!tmp)
1259 		return -ENOMEM;
1260 
1261 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1262 	quota_root = fs_info->quota_root;
1263 	if (!quota_root) {
1264 		ret = -EINVAL;
1265 		goto out;
1266 	}
1267 	member = find_qgroup_rb(fs_info, src);
1268 	parent = find_qgroup_rb(fs_info, dst);
1269 	if (!member || !parent) {
1270 		ret = -EINVAL;
1271 		goto out;
1272 	}
1273 
1274 	/* check if such qgroup relation exist firstly */
1275 	list_for_each_entry(list, &member->groups, next_group) {
1276 		if (list->group == parent) {
1277 			ret = -EEXIST;
1278 			goto out;
1279 		}
1280 	}
1281 
1282 	ret = add_qgroup_relation_item(trans, src, dst);
1283 	if (ret)
1284 		goto out;
1285 
1286 	ret = add_qgroup_relation_item(trans, dst, src);
1287 	if (ret) {
1288 		del_qgroup_relation_item(trans, src, dst);
1289 		goto out;
1290 	}
1291 
1292 	spin_lock(&fs_info->qgroup_lock);
1293 	ret = add_relation_rb(fs_info, src, dst);
1294 	if (ret < 0) {
1295 		spin_unlock(&fs_info->qgroup_lock);
1296 		goto out;
1297 	}
1298 	ret = quick_update_accounting(fs_info, tmp, src, dst, 1);
1299 	spin_unlock(&fs_info->qgroup_lock);
1300 out:
1301 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1302 	ulist_free(tmp);
1303 	return ret;
1304 }
1305 
1306 static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1307 				 u64 dst)
1308 {
1309 	struct btrfs_fs_info *fs_info = trans->fs_info;
1310 	struct btrfs_root *quota_root;
1311 	struct btrfs_qgroup *parent;
1312 	struct btrfs_qgroup *member;
1313 	struct btrfs_qgroup_list *list;
1314 	struct ulist *tmp;
1315 	int ret = 0;
1316 	int err;
1317 
1318 	tmp = ulist_alloc(GFP_KERNEL);
1319 	if (!tmp)
1320 		return -ENOMEM;
1321 
1322 	quota_root = fs_info->quota_root;
1323 	if (!quota_root) {
1324 		ret = -EINVAL;
1325 		goto out;
1326 	}
1327 
1328 	member = find_qgroup_rb(fs_info, src);
1329 	parent = find_qgroup_rb(fs_info, dst);
1330 	if (!member || !parent) {
1331 		ret = -EINVAL;
1332 		goto out;
1333 	}
1334 
1335 	/* check if such qgroup relation exist firstly */
1336 	list_for_each_entry(list, &member->groups, next_group) {
1337 		if (list->group == parent)
1338 			goto exist;
1339 	}
1340 	ret = -ENOENT;
1341 	goto out;
1342 exist:
1343 	ret = del_qgroup_relation_item(trans, src, dst);
1344 	err = del_qgroup_relation_item(trans, dst, src);
1345 	if (err && !ret)
1346 		ret = err;
1347 
1348 	spin_lock(&fs_info->qgroup_lock);
1349 	del_relation_rb(fs_info, src, dst);
1350 	ret = quick_update_accounting(fs_info, tmp, src, dst, -1);
1351 	spin_unlock(&fs_info->qgroup_lock);
1352 out:
1353 	ulist_free(tmp);
1354 	return ret;
1355 }
1356 
1357 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1358 			      u64 dst)
1359 {
1360 	struct btrfs_fs_info *fs_info = trans->fs_info;
1361 	int ret = 0;
1362 
1363 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1364 	ret = __del_qgroup_relation(trans, src, dst);
1365 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1366 
1367 	return ret;
1368 }
1369 
1370 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1371 {
1372 	struct btrfs_fs_info *fs_info = trans->fs_info;
1373 	struct btrfs_root *quota_root;
1374 	struct btrfs_qgroup *qgroup;
1375 	int ret = 0;
1376 
1377 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1378 	quota_root = fs_info->quota_root;
1379 	if (!quota_root) {
1380 		ret = -EINVAL;
1381 		goto out;
1382 	}
1383 	qgroup = find_qgroup_rb(fs_info, qgroupid);
1384 	if (qgroup) {
1385 		ret = -EEXIST;
1386 		goto out;
1387 	}
1388 
1389 	ret = add_qgroup_item(trans, quota_root, qgroupid);
1390 	if (ret)
1391 		goto out;
1392 
1393 	spin_lock(&fs_info->qgroup_lock);
1394 	qgroup = add_qgroup_rb(fs_info, qgroupid);
1395 	spin_unlock(&fs_info->qgroup_lock);
1396 
1397 	if (IS_ERR(qgroup))
1398 		ret = PTR_ERR(qgroup);
1399 out:
1400 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1401 	return ret;
1402 }
1403 
1404 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1405 {
1406 	struct btrfs_fs_info *fs_info = trans->fs_info;
1407 	struct btrfs_root *quota_root;
1408 	struct btrfs_qgroup *qgroup;
1409 	struct btrfs_qgroup_list *list;
1410 	int ret = 0;
1411 
1412 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1413 	quota_root = fs_info->quota_root;
1414 	if (!quota_root) {
1415 		ret = -EINVAL;
1416 		goto out;
1417 	}
1418 
1419 	qgroup = find_qgroup_rb(fs_info, qgroupid);
1420 	if (!qgroup) {
1421 		ret = -ENOENT;
1422 		goto out;
1423 	}
1424 
1425 	/* Check if there are no children of this qgroup */
1426 	if (!list_empty(&qgroup->members)) {
1427 		ret = -EBUSY;
1428 		goto out;
1429 	}
1430 
1431 	ret = del_qgroup_item(trans, qgroupid);
1432 	if (ret && ret != -ENOENT)
1433 		goto out;
1434 
1435 	while (!list_empty(&qgroup->groups)) {
1436 		list = list_first_entry(&qgroup->groups,
1437 					struct btrfs_qgroup_list, next_group);
1438 		ret = __del_qgroup_relation(trans, qgroupid,
1439 					    list->group->qgroupid);
1440 		if (ret)
1441 			goto out;
1442 	}
1443 
1444 	spin_lock(&fs_info->qgroup_lock);
1445 	del_qgroup_rb(fs_info, qgroupid);
1446 	spin_unlock(&fs_info->qgroup_lock);
1447 out:
1448 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1449 	return ret;
1450 }
1451 
1452 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
1453 		       struct btrfs_qgroup_limit *limit)
1454 {
1455 	struct btrfs_fs_info *fs_info = trans->fs_info;
1456 	struct btrfs_root *quota_root;
1457 	struct btrfs_qgroup *qgroup;
1458 	int ret = 0;
1459 	/* Sometimes we would want to clear the limit on this qgroup.
1460 	 * To meet this requirement, we treat the -1 as a special value
1461 	 * which tell kernel to clear the limit on this qgroup.
1462 	 */
1463 	const u64 CLEAR_VALUE = -1;
1464 
1465 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1466 	quota_root = fs_info->quota_root;
1467 	if (!quota_root) {
1468 		ret = -EINVAL;
1469 		goto out;
1470 	}
1471 
1472 	qgroup = find_qgroup_rb(fs_info, qgroupid);
1473 	if (!qgroup) {
1474 		ret = -ENOENT;
1475 		goto out;
1476 	}
1477 
1478 	spin_lock(&fs_info->qgroup_lock);
1479 	if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_RFER) {
1480 		if (limit->max_rfer == CLEAR_VALUE) {
1481 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1482 			limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1483 			qgroup->max_rfer = 0;
1484 		} else {
1485 			qgroup->max_rfer = limit->max_rfer;
1486 		}
1487 	}
1488 	if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
1489 		if (limit->max_excl == CLEAR_VALUE) {
1490 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1491 			limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1492 			qgroup->max_excl = 0;
1493 		} else {
1494 			qgroup->max_excl = limit->max_excl;
1495 		}
1496 	}
1497 	if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_RFER) {
1498 		if (limit->rsv_rfer == CLEAR_VALUE) {
1499 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1500 			limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1501 			qgroup->rsv_rfer = 0;
1502 		} else {
1503 			qgroup->rsv_rfer = limit->rsv_rfer;
1504 		}
1505 	}
1506 	if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_EXCL) {
1507 		if (limit->rsv_excl == CLEAR_VALUE) {
1508 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1509 			limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1510 			qgroup->rsv_excl = 0;
1511 		} else {
1512 			qgroup->rsv_excl = limit->rsv_excl;
1513 		}
1514 	}
1515 	qgroup->lim_flags |= limit->flags;
1516 
1517 	spin_unlock(&fs_info->qgroup_lock);
1518 
1519 	ret = update_qgroup_limit_item(trans, qgroup);
1520 	if (ret) {
1521 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1522 		btrfs_info(fs_info, "unable to update quota limit for %llu",
1523 		       qgroupid);
1524 	}
1525 
1526 out:
1527 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1528 	return ret;
1529 }
1530 
1531 int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
1532 				struct btrfs_delayed_ref_root *delayed_refs,
1533 				struct btrfs_qgroup_extent_record *record)
1534 {
1535 	struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
1536 	struct rb_node *parent_node = NULL;
1537 	struct btrfs_qgroup_extent_record *entry;
1538 	u64 bytenr = record->bytenr;
1539 
1540 	lockdep_assert_held(&delayed_refs->lock);
1541 	trace_btrfs_qgroup_trace_extent(fs_info, record);
1542 
1543 	while (*p) {
1544 		parent_node = *p;
1545 		entry = rb_entry(parent_node, struct btrfs_qgroup_extent_record,
1546 				 node);
1547 		if (bytenr < entry->bytenr) {
1548 			p = &(*p)->rb_left;
1549 		} else if (bytenr > entry->bytenr) {
1550 			p = &(*p)->rb_right;
1551 		} else {
1552 			if (record->data_rsv && !entry->data_rsv) {
1553 				entry->data_rsv = record->data_rsv;
1554 				entry->data_rsv_refroot =
1555 					record->data_rsv_refroot;
1556 			}
1557 			return 1;
1558 		}
1559 	}
1560 
1561 	rb_link_node(&record->node, parent_node, p);
1562 	rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
1563 	return 0;
1564 }
1565 
1566 int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
1567 				   struct btrfs_qgroup_extent_record *qrecord)
1568 {
1569 	struct ulist *old_root;
1570 	u64 bytenr = qrecord->bytenr;
1571 	int ret;
1572 
1573 	ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false);
1574 	if (ret < 0) {
1575 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1576 		btrfs_warn(fs_info,
1577 "error accounting new delayed refs extent (err code: %d), quota inconsistent",
1578 			ret);
1579 		return 0;
1580 	}
1581 
1582 	/*
1583 	 * Here we don't need to get the lock of
1584 	 * trans->transaction->delayed_refs, since inserted qrecord won't
1585 	 * be deleted, only qrecord->node may be modified (new qrecord insert)
1586 	 *
1587 	 * So modifying qrecord->old_roots is safe here
1588 	 */
1589 	qrecord->old_roots = old_root;
1590 	return 0;
1591 }
1592 
1593 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
1594 			      u64 num_bytes, gfp_t gfp_flag)
1595 {
1596 	struct btrfs_fs_info *fs_info = trans->fs_info;
1597 	struct btrfs_qgroup_extent_record *record;
1598 	struct btrfs_delayed_ref_root *delayed_refs;
1599 	int ret;
1600 
1601 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)
1602 	    || bytenr == 0 || num_bytes == 0)
1603 		return 0;
1604 	record = kzalloc(sizeof(*record), gfp_flag);
1605 	if (!record)
1606 		return -ENOMEM;
1607 
1608 	delayed_refs = &trans->transaction->delayed_refs;
1609 	record->bytenr = bytenr;
1610 	record->num_bytes = num_bytes;
1611 	record->old_roots = NULL;
1612 
1613 	spin_lock(&delayed_refs->lock);
1614 	ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record);
1615 	spin_unlock(&delayed_refs->lock);
1616 	if (ret > 0) {
1617 		kfree(record);
1618 		return 0;
1619 	}
1620 	return btrfs_qgroup_trace_extent_post(fs_info, record);
1621 }
1622 
1623 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
1624 				  struct extent_buffer *eb)
1625 {
1626 	struct btrfs_fs_info *fs_info = trans->fs_info;
1627 	int nr = btrfs_header_nritems(eb);
1628 	int i, extent_type, ret;
1629 	struct btrfs_key key;
1630 	struct btrfs_file_extent_item *fi;
1631 	u64 bytenr, num_bytes;
1632 
1633 	/* We can be called directly from walk_up_proc() */
1634 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1635 		return 0;
1636 
1637 	for (i = 0; i < nr; i++) {
1638 		btrfs_item_key_to_cpu(eb, &key, i);
1639 
1640 		if (key.type != BTRFS_EXTENT_DATA_KEY)
1641 			continue;
1642 
1643 		fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
1644 		/* filter out non qgroup-accountable extents  */
1645 		extent_type = btrfs_file_extent_type(eb, fi);
1646 
1647 		if (extent_type == BTRFS_FILE_EXTENT_INLINE)
1648 			continue;
1649 
1650 		bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
1651 		if (!bytenr)
1652 			continue;
1653 
1654 		num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
1655 
1656 		ret = btrfs_qgroup_trace_extent(trans, bytenr, num_bytes,
1657 						GFP_NOFS);
1658 		if (ret)
1659 			return ret;
1660 	}
1661 	cond_resched();
1662 	return 0;
1663 }
1664 
1665 /*
1666  * Walk up the tree from the bottom, freeing leaves and any interior
1667  * nodes which have had all slots visited. If a node (leaf or
1668  * interior) is freed, the node above it will have it's slot
1669  * incremented. The root node will never be freed.
1670  *
1671  * At the end of this function, we should have a path which has all
1672  * slots incremented to the next position for a search. If we need to
1673  * read a new node it will be NULL and the node above it will have the
1674  * correct slot selected for a later read.
1675  *
1676  * If we increment the root nodes slot counter past the number of
1677  * elements, 1 is returned to signal completion of the search.
1678  */
1679 static int adjust_slots_upwards(struct btrfs_path *path, int root_level)
1680 {
1681 	int level = 0;
1682 	int nr, slot;
1683 	struct extent_buffer *eb;
1684 
1685 	if (root_level == 0)
1686 		return 1;
1687 
1688 	while (level <= root_level) {
1689 		eb = path->nodes[level];
1690 		nr = btrfs_header_nritems(eb);
1691 		path->slots[level]++;
1692 		slot = path->slots[level];
1693 		if (slot >= nr || level == 0) {
1694 			/*
1695 			 * Don't free the root -  we will detect this
1696 			 * condition after our loop and return a
1697 			 * positive value for caller to stop walking the tree.
1698 			 */
1699 			if (level != root_level) {
1700 				btrfs_tree_unlock_rw(eb, path->locks[level]);
1701 				path->locks[level] = 0;
1702 
1703 				free_extent_buffer(eb);
1704 				path->nodes[level] = NULL;
1705 				path->slots[level] = 0;
1706 			}
1707 		} else {
1708 			/*
1709 			 * We have a valid slot to walk back down
1710 			 * from. Stop here so caller can process these
1711 			 * new nodes.
1712 			 */
1713 			break;
1714 		}
1715 
1716 		level++;
1717 	}
1718 
1719 	eb = path->nodes[root_level];
1720 	if (path->slots[root_level] >= btrfs_header_nritems(eb))
1721 		return 1;
1722 
1723 	return 0;
1724 }
1725 
1726 /*
1727  * Helper function to trace a subtree tree block swap.
1728  *
1729  * The swap will happen in highest tree block, but there may be a lot of
1730  * tree blocks involved.
1731  *
1732  * For example:
1733  *  OO = Old tree blocks
1734  *  NN = New tree blocks allocated during balance
1735  *
1736  *           File tree (257)                  Reloc tree for 257
1737  * L2              OO                                NN
1738  *               /    \                            /    \
1739  * L1          OO      OO (a)                    OO      NN (a)
1740  *            / \     / \                       / \     / \
1741  * L0       OO   OO OO   OO                   OO   OO NN   NN
1742  *                  (b)  (c)                          (b)  (c)
1743  *
1744  * When calling qgroup_trace_extent_swap(), we will pass:
1745  * @src_eb = OO(a)
1746  * @dst_path = [ nodes[1] = NN(a), nodes[0] = NN(c) ]
1747  * @dst_level = 0
1748  * @root_level = 1
1749  *
1750  * In that case, qgroup_trace_extent_swap() will search from OO(a) to
1751  * reach OO(c), then mark both OO(c) and NN(c) as qgroup dirty.
1752  *
1753  * The main work of qgroup_trace_extent_swap() can be split into 3 parts:
1754  *
1755  * 1) Tree search from @src_eb
1756  *    It should acts as a simplified btrfs_search_slot().
1757  *    The key for search can be extracted from @dst_path->nodes[dst_level]
1758  *    (first key).
1759  *
1760  * 2) Mark the final tree blocks in @src_path and @dst_path qgroup dirty
1761  *    NOTE: In above case, OO(a) and NN(a) won't be marked qgroup dirty.
1762  *    They should be marked during previous (@dst_level = 1) iteration.
1763  *
1764  * 3) Mark file extents in leaves dirty
1765  *    We don't have good way to pick out new file extents only.
1766  *    So we still follow the old method by scanning all file extents in
1767  *    the leave.
1768  *
1769  * This function can free us from keeping two paths, thus later we only need
1770  * to care about how to iterate all new tree blocks in reloc tree.
1771  */
1772 static int qgroup_trace_extent_swap(struct btrfs_trans_handle* trans,
1773 				    struct extent_buffer *src_eb,
1774 				    struct btrfs_path *dst_path,
1775 				    int dst_level, int root_level,
1776 				    bool trace_leaf)
1777 {
1778 	struct btrfs_key key;
1779 	struct btrfs_path *src_path;
1780 	struct btrfs_fs_info *fs_info = trans->fs_info;
1781 	u32 nodesize = fs_info->nodesize;
1782 	int cur_level = root_level;
1783 	int ret;
1784 
1785 	BUG_ON(dst_level > root_level);
1786 	/* Level mismatch */
1787 	if (btrfs_header_level(src_eb) != root_level)
1788 		return -EINVAL;
1789 
1790 	src_path = btrfs_alloc_path();
1791 	if (!src_path) {
1792 		ret = -ENOMEM;
1793 		goto out;
1794 	}
1795 
1796 	if (dst_level)
1797 		btrfs_node_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
1798 	else
1799 		btrfs_item_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
1800 
1801 	/* For src_path */
1802 	extent_buffer_get(src_eb);
1803 	src_path->nodes[root_level] = src_eb;
1804 	src_path->slots[root_level] = dst_path->slots[root_level];
1805 	src_path->locks[root_level] = 0;
1806 
1807 	/* A simplified version of btrfs_search_slot() */
1808 	while (cur_level >= dst_level) {
1809 		struct btrfs_key src_key;
1810 		struct btrfs_key dst_key;
1811 
1812 		if (src_path->nodes[cur_level] == NULL) {
1813 			struct btrfs_key first_key;
1814 			struct extent_buffer *eb;
1815 			int parent_slot;
1816 			u64 child_gen;
1817 			u64 child_bytenr;
1818 
1819 			eb = src_path->nodes[cur_level + 1];
1820 			parent_slot = src_path->slots[cur_level + 1];
1821 			child_bytenr = btrfs_node_blockptr(eb, parent_slot);
1822 			child_gen = btrfs_node_ptr_generation(eb, parent_slot);
1823 			btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
1824 
1825 			eb = read_tree_block(fs_info, child_bytenr, child_gen,
1826 					     cur_level, &first_key);
1827 			if (IS_ERR(eb)) {
1828 				ret = PTR_ERR(eb);
1829 				goto out;
1830 			} else if (!extent_buffer_uptodate(eb)) {
1831 				free_extent_buffer(eb);
1832 				ret = -EIO;
1833 				goto out;
1834 			}
1835 
1836 			src_path->nodes[cur_level] = eb;
1837 
1838 			btrfs_tree_read_lock(eb);
1839 			btrfs_set_lock_blocking_read(eb);
1840 			src_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
1841 		}
1842 
1843 		src_path->slots[cur_level] = dst_path->slots[cur_level];
1844 		if (cur_level) {
1845 			btrfs_node_key_to_cpu(dst_path->nodes[cur_level],
1846 					&dst_key, dst_path->slots[cur_level]);
1847 			btrfs_node_key_to_cpu(src_path->nodes[cur_level],
1848 					&src_key, src_path->slots[cur_level]);
1849 		} else {
1850 			btrfs_item_key_to_cpu(dst_path->nodes[cur_level],
1851 					&dst_key, dst_path->slots[cur_level]);
1852 			btrfs_item_key_to_cpu(src_path->nodes[cur_level],
1853 					&src_key, src_path->slots[cur_level]);
1854 		}
1855 		/* Content mismatch, something went wrong */
1856 		if (btrfs_comp_cpu_keys(&dst_key, &src_key)) {
1857 			ret = -ENOENT;
1858 			goto out;
1859 		}
1860 		cur_level--;
1861 	}
1862 
1863 	/*
1864 	 * Now both @dst_path and @src_path have been populated, record the tree
1865 	 * blocks for qgroup accounting.
1866 	 */
1867 	ret = btrfs_qgroup_trace_extent(trans, src_path->nodes[dst_level]->start,
1868 			nodesize, GFP_NOFS);
1869 	if (ret < 0)
1870 		goto out;
1871 	ret = btrfs_qgroup_trace_extent(trans,
1872 			dst_path->nodes[dst_level]->start,
1873 			nodesize, GFP_NOFS);
1874 	if (ret < 0)
1875 		goto out;
1876 
1877 	/* Record leaf file extents */
1878 	if (dst_level == 0 && trace_leaf) {
1879 		ret = btrfs_qgroup_trace_leaf_items(trans, src_path->nodes[0]);
1880 		if (ret < 0)
1881 			goto out;
1882 		ret = btrfs_qgroup_trace_leaf_items(trans, dst_path->nodes[0]);
1883 	}
1884 out:
1885 	btrfs_free_path(src_path);
1886 	return ret;
1887 }
1888 
1889 /*
1890  * Helper function to do recursive generation-aware depth-first search, to
1891  * locate all new tree blocks in a subtree of reloc tree.
1892  *
1893  * E.g. (OO = Old tree blocks, NN = New tree blocks, whose gen == last_snapshot)
1894  *         reloc tree
1895  * L2         NN (a)
1896  *          /    \
1897  * L1    OO        NN (b)
1898  *      /  \      /  \
1899  * L0  OO  OO    OO  NN
1900  *               (c) (d)
1901  * If we pass:
1902  * @dst_path = [ nodes[1] = NN(b), nodes[0] = NULL ],
1903  * @cur_level = 1
1904  * @root_level = 1
1905  *
1906  * We will iterate through tree blocks NN(b), NN(d) and info qgroup to trace
1907  * above tree blocks along with their counter parts in file tree.
1908  * While during search, old tree blocks OO(c) will be skipped as tree block swap
1909  * won't affect OO(c).
1910  */
1911 static int qgroup_trace_new_subtree_blocks(struct btrfs_trans_handle* trans,
1912 					   struct extent_buffer *src_eb,
1913 					   struct btrfs_path *dst_path,
1914 					   int cur_level, int root_level,
1915 					   u64 last_snapshot, bool trace_leaf)
1916 {
1917 	struct btrfs_fs_info *fs_info = trans->fs_info;
1918 	struct extent_buffer *eb;
1919 	bool need_cleanup = false;
1920 	int ret = 0;
1921 	int i;
1922 
1923 	/* Level sanity check */
1924 	if (cur_level < 0 || cur_level >= BTRFS_MAX_LEVEL - 1 ||
1925 	    root_level < 0 || root_level >= BTRFS_MAX_LEVEL - 1 ||
1926 	    root_level < cur_level) {
1927 		btrfs_err_rl(fs_info,
1928 			"%s: bad levels, cur_level=%d root_level=%d",
1929 			__func__, cur_level, root_level);
1930 		return -EUCLEAN;
1931 	}
1932 
1933 	/* Read the tree block if needed */
1934 	if (dst_path->nodes[cur_level] == NULL) {
1935 		struct btrfs_key first_key;
1936 		int parent_slot;
1937 		u64 child_gen;
1938 		u64 child_bytenr;
1939 
1940 		/*
1941 		 * dst_path->nodes[root_level] must be initialized before
1942 		 * calling this function.
1943 		 */
1944 		if (cur_level == root_level) {
1945 			btrfs_err_rl(fs_info,
1946 	"%s: dst_path->nodes[%d] not initialized, root_level=%d cur_level=%d",
1947 				__func__, root_level, root_level, cur_level);
1948 			return -EUCLEAN;
1949 		}
1950 
1951 		/*
1952 		 * We need to get child blockptr/gen from parent before we can
1953 		 * read it.
1954 		  */
1955 		eb = dst_path->nodes[cur_level + 1];
1956 		parent_slot = dst_path->slots[cur_level + 1];
1957 		child_bytenr = btrfs_node_blockptr(eb, parent_slot);
1958 		child_gen = btrfs_node_ptr_generation(eb, parent_slot);
1959 		btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
1960 
1961 		/* This node is old, no need to trace */
1962 		if (child_gen < last_snapshot)
1963 			goto out;
1964 
1965 		eb = read_tree_block(fs_info, child_bytenr, child_gen,
1966 				     cur_level, &first_key);
1967 		if (IS_ERR(eb)) {
1968 			ret = PTR_ERR(eb);
1969 			goto out;
1970 		} else if (!extent_buffer_uptodate(eb)) {
1971 			free_extent_buffer(eb);
1972 			ret = -EIO;
1973 			goto out;
1974 		}
1975 
1976 		dst_path->nodes[cur_level] = eb;
1977 		dst_path->slots[cur_level] = 0;
1978 
1979 		btrfs_tree_read_lock(eb);
1980 		btrfs_set_lock_blocking_read(eb);
1981 		dst_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
1982 		need_cleanup = true;
1983 	}
1984 
1985 	/* Now record this tree block and its counter part for qgroups */
1986 	ret = qgroup_trace_extent_swap(trans, src_eb, dst_path, cur_level,
1987 				       root_level, trace_leaf);
1988 	if (ret < 0)
1989 		goto cleanup;
1990 
1991 	eb = dst_path->nodes[cur_level];
1992 
1993 	if (cur_level > 0) {
1994 		/* Iterate all child tree blocks */
1995 		for (i = 0; i < btrfs_header_nritems(eb); i++) {
1996 			/* Skip old tree blocks as they won't be swapped */
1997 			if (btrfs_node_ptr_generation(eb, i) < last_snapshot)
1998 				continue;
1999 			dst_path->slots[cur_level] = i;
2000 
2001 			/* Recursive call (at most 7 times) */
2002 			ret = qgroup_trace_new_subtree_blocks(trans, src_eb,
2003 					dst_path, cur_level - 1, root_level,
2004 					last_snapshot, trace_leaf);
2005 			if (ret < 0)
2006 				goto cleanup;
2007 		}
2008 	}
2009 
2010 cleanup:
2011 	if (need_cleanup) {
2012 		/* Clean up */
2013 		btrfs_tree_unlock_rw(dst_path->nodes[cur_level],
2014 				     dst_path->locks[cur_level]);
2015 		free_extent_buffer(dst_path->nodes[cur_level]);
2016 		dst_path->nodes[cur_level] = NULL;
2017 		dst_path->slots[cur_level] = 0;
2018 		dst_path->locks[cur_level] = 0;
2019 	}
2020 out:
2021 	return ret;
2022 }
2023 
2024 static int qgroup_trace_subtree_swap(struct btrfs_trans_handle *trans,
2025 				struct extent_buffer *src_eb,
2026 				struct extent_buffer *dst_eb,
2027 				u64 last_snapshot, bool trace_leaf)
2028 {
2029 	struct btrfs_fs_info *fs_info = trans->fs_info;
2030 	struct btrfs_path *dst_path = NULL;
2031 	int level;
2032 	int ret;
2033 
2034 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2035 		return 0;
2036 
2037 	/* Wrong parameter order */
2038 	if (btrfs_header_generation(src_eb) > btrfs_header_generation(dst_eb)) {
2039 		btrfs_err_rl(fs_info,
2040 		"%s: bad parameter order, src_gen=%llu dst_gen=%llu", __func__,
2041 			     btrfs_header_generation(src_eb),
2042 			     btrfs_header_generation(dst_eb));
2043 		return -EUCLEAN;
2044 	}
2045 
2046 	if (!extent_buffer_uptodate(src_eb) || !extent_buffer_uptodate(dst_eb)) {
2047 		ret = -EIO;
2048 		goto out;
2049 	}
2050 
2051 	level = btrfs_header_level(dst_eb);
2052 	dst_path = btrfs_alloc_path();
2053 	if (!dst_path) {
2054 		ret = -ENOMEM;
2055 		goto out;
2056 	}
2057 	/* For dst_path */
2058 	extent_buffer_get(dst_eb);
2059 	dst_path->nodes[level] = dst_eb;
2060 	dst_path->slots[level] = 0;
2061 	dst_path->locks[level] = 0;
2062 
2063 	/* Do the generation aware breadth-first search */
2064 	ret = qgroup_trace_new_subtree_blocks(trans, src_eb, dst_path, level,
2065 					      level, last_snapshot, trace_leaf);
2066 	if (ret < 0)
2067 		goto out;
2068 	ret = 0;
2069 
2070 out:
2071 	btrfs_free_path(dst_path);
2072 	if (ret < 0)
2073 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2074 	return ret;
2075 }
2076 
2077 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
2078 			       struct extent_buffer *root_eb,
2079 			       u64 root_gen, int root_level)
2080 {
2081 	struct btrfs_fs_info *fs_info = trans->fs_info;
2082 	int ret = 0;
2083 	int level;
2084 	struct extent_buffer *eb = root_eb;
2085 	struct btrfs_path *path = NULL;
2086 
2087 	BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
2088 	BUG_ON(root_eb == NULL);
2089 
2090 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2091 		return 0;
2092 
2093 	if (!extent_buffer_uptodate(root_eb)) {
2094 		ret = btrfs_read_buffer(root_eb, root_gen, root_level, NULL);
2095 		if (ret)
2096 			goto out;
2097 	}
2098 
2099 	if (root_level == 0) {
2100 		ret = btrfs_qgroup_trace_leaf_items(trans, root_eb);
2101 		goto out;
2102 	}
2103 
2104 	path = btrfs_alloc_path();
2105 	if (!path)
2106 		return -ENOMEM;
2107 
2108 	/*
2109 	 * Walk down the tree.  Missing extent blocks are filled in as
2110 	 * we go. Metadata is accounted every time we read a new
2111 	 * extent block.
2112 	 *
2113 	 * When we reach a leaf, we account for file extent items in it,
2114 	 * walk back up the tree (adjusting slot pointers as we go)
2115 	 * and restart the search process.
2116 	 */
2117 	extent_buffer_get(root_eb); /* For path */
2118 	path->nodes[root_level] = root_eb;
2119 	path->slots[root_level] = 0;
2120 	path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
2121 walk_down:
2122 	level = root_level;
2123 	while (level >= 0) {
2124 		if (path->nodes[level] == NULL) {
2125 			struct btrfs_key first_key;
2126 			int parent_slot;
2127 			u64 child_gen;
2128 			u64 child_bytenr;
2129 
2130 			/*
2131 			 * We need to get child blockptr/gen from parent before
2132 			 * we can read it.
2133 			  */
2134 			eb = path->nodes[level + 1];
2135 			parent_slot = path->slots[level + 1];
2136 			child_bytenr = btrfs_node_blockptr(eb, parent_slot);
2137 			child_gen = btrfs_node_ptr_generation(eb, parent_slot);
2138 			btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
2139 
2140 			eb = read_tree_block(fs_info, child_bytenr, child_gen,
2141 					     level, &first_key);
2142 			if (IS_ERR(eb)) {
2143 				ret = PTR_ERR(eb);
2144 				goto out;
2145 			} else if (!extent_buffer_uptodate(eb)) {
2146 				free_extent_buffer(eb);
2147 				ret = -EIO;
2148 				goto out;
2149 			}
2150 
2151 			path->nodes[level] = eb;
2152 			path->slots[level] = 0;
2153 
2154 			btrfs_tree_read_lock(eb);
2155 			btrfs_set_lock_blocking_read(eb);
2156 			path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
2157 
2158 			ret = btrfs_qgroup_trace_extent(trans, child_bytenr,
2159 							fs_info->nodesize,
2160 							GFP_NOFS);
2161 			if (ret)
2162 				goto out;
2163 		}
2164 
2165 		if (level == 0) {
2166 			ret = btrfs_qgroup_trace_leaf_items(trans,
2167 							    path->nodes[level]);
2168 			if (ret)
2169 				goto out;
2170 
2171 			/* Nonzero return here means we completed our search */
2172 			ret = adjust_slots_upwards(path, root_level);
2173 			if (ret)
2174 				break;
2175 
2176 			/* Restart search with new slots */
2177 			goto walk_down;
2178 		}
2179 
2180 		level--;
2181 	}
2182 
2183 	ret = 0;
2184 out:
2185 	btrfs_free_path(path);
2186 
2187 	return ret;
2188 }
2189 
2190 #define UPDATE_NEW	0
2191 #define UPDATE_OLD	1
2192 /*
2193  * Walk all of the roots that points to the bytenr and adjust their refcnts.
2194  */
2195 static int qgroup_update_refcnt(struct btrfs_fs_info *fs_info,
2196 				struct ulist *roots, struct ulist *tmp,
2197 				struct ulist *qgroups, u64 seq, int update_old)
2198 {
2199 	struct ulist_node *unode;
2200 	struct ulist_iterator uiter;
2201 	struct ulist_node *tmp_unode;
2202 	struct ulist_iterator tmp_uiter;
2203 	struct btrfs_qgroup *qg;
2204 	int ret = 0;
2205 
2206 	if (!roots)
2207 		return 0;
2208 	ULIST_ITER_INIT(&uiter);
2209 	while ((unode = ulist_next(roots, &uiter))) {
2210 		qg = find_qgroup_rb(fs_info, unode->val);
2211 		if (!qg)
2212 			continue;
2213 
2214 		ulist_reinit(tmp);
2215 		ret = ulist_add(qgroups, qg->qgroupid, qgroup_to_aux(qg),
2216 				GFP_ATOMIC);
2217 		if (ret < 0)
2218 			return ret;
2219 		ret = ulist_add(tmp, qg->qgroupid, qgroup_to_aux(qg), GFP_ATOMIC);
2220 		if (ret < 0)
2221 			return ret;
2222 		ULIST_ITER_INIT(&tmp_uiter);
2223 		while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
2224 			struct btrfs_qgroup_list *glist;
2225 
2226 			qg = unode_aux_to_qgroup(tmp_unode);
2227 			if (update_old)
2228 				btrfs_qgroup_update_old_refcnt(qg, seq, 1);
2229 			else
2230 				btrfs_qgroup_update_new_refcnt(qg, seq, 1);
2231 			list_for_each_entry(glist, &qg->groups, next_group) {
2232 				ret = ulist_add(qgroups, glist->group->qgroupid,
2233 						qgroup_to_aux(glist->group),
2234 						GFP_ATOMIC);
2235 				if (ret < 0)
2236 					return ret;
2237 				ret = ulist_add(tmp, glist->group->qgroupid,
2238 						qgroup_to_aux(glist->group),
2239 						GFP_ATOMIC);
2240 				if (ret < 0)
2241 					return ret;
2242 			}
2243 		}
2244 	}
2245 	return 0;
2246 }
2247 
2248 /*
2249  * Update qgroup rfer/excl counters.
2250  * Rfer update is easy, codes can explain themselves.
2251  *
2252  * Excl update is tricky, the update is split into 2 part.
2253  * Part 1: Possible exclusive <-> sharing detect:
2254  *	|	A	|	!A	|
2255  *  -------------------------------------
2256  *  B	|	*	|	-	|
2257  *  -------------------------------------
2258  *  !B	|	+	|	**	|
2259  *  -------------------------------------
2260  *
2261  * Conditions:
2262  * A:	cur_old_roots < nr_old_roots	(not exclusive before)
2263  * !A:	cur_old_roots == nr_old_roots	(possible exclusive before)
2264  * B:	cur_new_roots < nr_new_roots	(not exclusive now)
2265  * !B:	cur_new_roots == nr_new_roots	(possible exclusive now)
2266  *
2267  * Results:
2268  * +: Possible sharing -> exclusive	-: Possible exclusive -> sharing
2269  * *: Definitely not changed.		**: Possible unchanged.
2270  *
2271  * For !A and !B condition, the exception is cur_old/new_roots == 0 case.
2272  *
2273  * To make the logic clear, we first use condition A and B to split
2274  * combination into 4 results.
2275  *
2276  * Then, for result "+" and "-", check old/new_roots == 0 case, as in them
2277  * only on variant maybe 0.
2278  *
2279  * Lastly, check result **, since there are 2 variants maybe 0, split them
2280  * again(2x2).
2281  * But this time we don't need to consider other things, the codes and logic
2282  * is easy to understand now.
2283  */
2284 static int qgroup_update_counters(struct btrfs_fs_info *fs_info,
2285 				  struct ulist *qgroups,
2286 				  u64 nr_old_roots,
2287 				  u64 nr_new_roots,
2288 				  u64 num_bytes, u64 seq)
2289 {
2290 	struct ulist_node *unode;
2291 	struct ulist_iterator uiter;
2292 	struct btrfs_qgroup *qg;
2293 	u64 cur_new_count, cur_old_count;
2294 
2295 	ULIST_ITER_INIT(&uiter);
2296 	while ((unode = ulist_next(qgroups, &uiter))) {
2297 		bool dirty = false;
2298 
2299 		qg = unode_aux_to_qgroup(unode);
2300 		cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
2301 		cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
2302 
2303 		trace_qgroup_update_counters(fs_info, qg, cur_old_count,
2304 					     cur_new_count);
2305 
2306 		/* Rfer update part */
2307 		if (cur_old_count == 0 && cur_new_count > 0) {
2308 			qg->rfer += num_bytes;
2309 			qg->rfer_cmpr += num_bytes;
2310 			dirty = true;
2311 		}
2312 		if (cur_old_count > 0 && cur_new_count == 0) {
2313 			qg->rfer -= num_bytes;
2314 			qg->rfer_cmpr -= num_bytes;
2315 			dirty = true;
2316 		}
2317 
2318 		/* Excl update part */
2319 		/* Exclusive/none -> shared case */
2320 		if (cur_old_count == nr_old_roots &&
2321 		    cur_new_count < nr_new_roots) {
2322 			/* Exclusive -> shared */
2323 			if (cur_old_count != 0) {
2324 				qg->excl -= num_bytes;
2325 				qg->excl_cmpr -= num_bytes;
2326 				dirty = true;
2327 			}
2328 		}
2329 
2330 		/* Shared -> exclusive/none case */
2331 		if (cur_old_count < nr_old_roots &&
2332 		    cur_new_count == nr_new_roots) {
2333 			/* Shared->exclusive */
2334 			if (cur_new_count != 0) {
2335 				qg->excl += num_bytes;
2336 				qg->excl_cmpr += num_bytes;
2337 				dirty = true;
2338 			}
2339 		}
2340 
2341 		/* Exclusive/none -> exclusive/none case */
2342 		if (cur_old_count == nr_old_roots &&
2343 		    cur_new_count == nr_new_roots) {
2344 			if (cur_old_count == 0) {
2345 				/* None -> exclusive/none */
2346 
2347 				if (cur_new_count != 0) {
2348 					/* None -> exclusive */
2349 					qg->excl += num_bytes;
2350 					qg->excl_cmpr += num_bytes;
2351 					dirty = true;
2352 				}
2353 				/* None -> none, nothing changed */
2354 			} else {
2355 				/* Exclusive -> exclusive/none */
2356 
2357 				if (cur_new_count == 0) {
2358 					/* Exclusive -> none */
2359 					qg->excl -= num_bytes;
2360 					qg->excl_cmpr -= num_bytes;
2361 					dirty = true;
2362 				}
2363 				/* Exclusive -> exclusive, nothing changed */
2364 			}
2365 		}
2366 
2367 		if (dirty)
2368 			qgroup_dirty(fs_info, qg);
2369 	}
2370 	return 0;
2371 }
2372 
2373 /*
2374  * Check if the @roots potentially is a list of fs tree roots
2375  *
2376  * Return 0 for definitely not a fs/subvol tree roots ulist
2377  * Return 1 for possible fs/subvol tree roots in the list (considering an empty
2378  *          one as well)
2379  */
2380 static int maybe_fs_roots(struct ulist *roots)
2381 {
2382 	struct ulist_node *unode;
2383 	struct ulist_iterator uiter;
2384 
2385 	/* Empty one, still possible for fs roots */
2386 	if (!roots || roots->nnodes == 0)
2387 		return 1;
2388 
2389 	ULIST_ITER_INIT(&uiter);
2390 	unode = ulist_next(roots, &uiter);
2391 	if (!unode)
2392 		return 1;
2393 
2394 	/*
2395 	 * If it contains fs tree roots, then it must belong to fs/subvol
2396 	 * trees.
2397 	 * If it contains a non-fs tree, it won't be shared with fs/subvol trees.
2398 	 */
2399 	return is_fstree(unode->val);
2400 }
2401 
2402 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
2403 				u64 num_bytes, struct ulist *old_roots,
2404 				struct ulist *new_roots)
2405 {
2406 	struct btrfs_fs_info *fs_info = trans->fs_info;
2407 	struct ulist *qgroups = NULL;
2408 	struct ulist *tmp = NULL;
2409 	u64 seq;
2410 	u64 nr_new_roots = 0;
2411 	u64 nr_old_roots = 0;
2412 	int ret = 0;
2413 
2414 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2415 		return 0;
2416 
2417 	if (new_roots) {
2418 		if (!maybe_fs_roots(new_roots))
2419 			goto out_free;
2420 		nr_new_roots = new_roots->nnodes;
2421 	}
2422 	if (old_roots) {
2423 		if (!maybe_fs_roots(old_roots))
2424 			goto out_free;
2425 		nr_old_roots = old_roots->nnodes;
2426 	}
2427 
2428 	/* Quick exit, either not fs tree roots, or won't affect any qgroup */
2429 	if (nr_old_roots == 0 && nr_new_roots == 0)
2430 		goto out_free;
2431 
2432 	BUG_ON(!fs_info->quota_root);
2433 
2434 	trace_btrfs_qgroup_account_extent(fs_info, trans->transid, bytenr,
2435 					num_bytes, nr_old_roots, nr_new_roots);
2436 
2437 	qgroups = ulist_alloc(GFP_NOFS);
2438 	if (!qgroups) {
2439 		ret = -ENOMEM;
2440 		goto out_free;
2441 	}
2442 	tmp = ulist_alloc(GFP_NOFS);
2443 	if (!tmp) {
2444 		ret = -ENOMEM;
2445 		goto out_free;
2446 	}
2447 
2448 	mutex_lock(&fs_info->qgroup_rescan_lock);
2449 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
2450 		if (fs_info->qgroup_rescan_progress.objectid <= bytenr) {
2451 			mutex_unlock(&fs_info->qgroup_rescan_lock);
2452 			ret = 0;
2453 			goto out_free;
2454 		}
2455 	}
2456 	mutex_unlock(&fs_info->qgroup_rescan_lock);
2457 
2458 	spin_lock(&fs_info->qgroup_lock);
2459 	seq = fs_info->qgroup_seq;
2460 
2461 	/* Update old refcnts using old_roots */
2462 	ret = qgroup_update_refcnt(fs_info, old_roots, tmp, qgroups, seq,
2463 				   UPDATE_OLD);
2464 	if (ret < 0)
2465 		goto out;
2466 
2467 	/* Update new refcnts using new_roots */
2468 	ret = qgroup_update_refcnt(fs_info, new_roots, tmp, qgroups, seq,
2469 				   UPDATE_NEW);
2470 	if (ret < 0)
2471 		goto out;
2472 
2473 	qgroup_update_counters(fs_info, qgroups, nr_old_roots, nr_new_roots,
2474 			       num_bytes, seq);
2475 
2476 	/*
2477 	 * Bump qgroup_seq to avoid seq overlap
2478 	 */
2479 	fs_info->qgroup_seq += max(nr_old_roots, nr_new_roots) + 1;
2480 out:
2481 	spin_unlock(&fs_info->qgroup_lock);
2482 out_free:
2483 	ulist_free(tmp);
2484 	ulist_free(qgroups);
2485 	ulist_free(old_roots);
2486 	ulist_free(new_roots);
2487 	return ret;
2488 }
2489 
2490 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
2491 {
2492 	struct btrfs_fs_info *fs_info = trans->fs_info;
2493 	struct btrfs_qgroup_extent_record *record;
2494 	struct btrfs_delayed_ref_root *delayed_refs;
2495 	struct ulist *new_roots = NULL;
2496 	struct rb_node *node;
2497 	u64 num_dirty_extents = 0;
2498 	u64 qgroup_to_skip;
2499 	int ret = 0;
2500 
2501 	delayed_refs = &trans->transaction->delayed_refs;
2502 	qgroup_to_skip = delayed_refs->qgroup_to_skip;
2503 	while ((node = rb_first(&delayed_refs->dirty_extent_root))) {
2504 		record = rb_entry(node, struct btrfs_qgroup_extent_record,
2505 				  node);
2506 
2507 		num_dirty_extents++;
2508 		trace_btrfs_qgroup_account_extents(fs_info, record);
2509 
2510 		if (!ret) {
2511 			/*
2512 			 * Old roots should be searched when inserting qgroup
2513 			 * extent record
2514 			 */
2515 			if (WARN_ON(!record->old_roots)) {
2516 				/* Search commit root to find old_roots */
2517 				ret = btrfs_find_all_roots(NULL, fs_info,
2518 						record->bytenr, 0,
2519 						&record->old_roots, false);
2520 				if (ret < 0)
2521 					goto cleanup;
2522 			}
2523 
2524 			/* Free the reserved data space */
2525 			btrfs_qgroup_free_refroot(fs_info,
2526 					record->data_rsv_refroot,
2527 					record->data_rsv,
2528 					BTRFS_QGROUP_RSV_DATA);
2529 			/*
2530 			 * Use SEQ_LAST as time_seq to do special search, which
2531 			 * doesn't lock tree or delayed_refs and search current
2532 			 * root. It's safe inside commit_transaction().
2533 			 */
2534 			ret = btrfs_find_all_roots(trans, fs_info,
2535 				record->bytenr, SEQ_LAST, &new_roots, false);
2536 			if (ret < 0)
2537 				goto cleanup;
2538 			if (qgroup_to_skip) {
2539 				ulist_del(new_roots, qgroup_to_skip, 0);
2540 				ulist_del(record->old_roots, qgroup_to_skip,
2541 					  0);
2542 			}
2543 			ret = btrfs_qgroup_account_extent(trans, record->bytenr,
2544 							  record->num_bytes,
2545 							  record->old_roots,
2546 							  new_roots);
2547 			record->old_roots = NULL;
2548 			new_roots = NULL;
2549 		}
2550 cleanup:
2551 		ulist_free(record->old_roots);
2552 		ulist_free(new_roots);
2553 		new_roots = NULL;
2554 		rb_erase(node, &delayed_refs->dirty_extent_root);
2555 		kfree(record);
2556 
2557 	}
2558 	trace_qgroup_num_dirty_extents(fs_info, trans->transid,
2559 				       num_dirty_extents);
2560 	return ret;
2561 }
2562 
2563 /*
2564  * called from commit_transaction. Writes all changed qgroups to disk.
2565  */
2566 int btrfs_run_qgroups(struct btrfs_trans_handle *trans)
2567 {
2568 	struct btrfs_fs_info *fs_info = trans->fs_info;
2569 	struct btrfs_root *quota_root = fs_info->quota_root;
2570 	int ret = 0;
2571 
2572 	if (!quota_root)
2573 		return ret;
2574 
2575 	spin_lock(&fs_info->qgroup_lock);
2576 	while (!list_empty(&fs_info->dirty_qgroups)) {
2577 		struct btrfs_qgroup *qgroup;
2578 		qgroup = list_first_entry(&fs_info->dirty_qgroups,
2579 					  struct btrfs_qgroup, dirty);
2580 		list_del_init(&qgroup->dirty);
2581 		spin_unlock(&fs_info->qgroup_lock);
2582 		ret = update_qgroup_info_item(trans, qgroup);
2583 		if (ret)
2584 			fs_info->qgroup_flags |=
2585 					BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2586 		ret = update_qgroup_limit_item(trans, qgroup);
2587 		if (ret)
2588 			fs_info->qgroup_flags |=
2589 					BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2590 		spin_lock(&fs_info->qgroup_lock);
2591 	}
2592 	if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2593 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_ON;
2594 	else
2595 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
2596 	spin_unlock(&fs_info->qgroup_lock);
2597 
2598 	ret = update_qgroup_status_item(trans);
2599 	if (ret)
2600 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2601 
2602 	return ret;
2603 }
2604 
2605 /*
2606  * Copy the accounting information between qgroups. This is necessary
2607  * when a snapshot or a subvolume is created. Throwing an error will
2608  * cause a transaction abort so we take extra care here to only error
2609  * when a readonly fs is a reasonable outcome.
2610  */
2611 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
2612 			 u64 objectid, struct btrfs_qgroup_inherit *inherit)
2613 {
2614 	int ret = 0;
2615 	int i;
2616 	u64 *i_qgroups;
2617 	struct btrfs_fs_info *fs_info = trans->fs_info;
2618 	struct btrfs_root *quota_root;
2619 	struct btrfs_qgroup *srcgroup;
2620 	struct btrfs_qgroup *dstgroup;
2621 	u32 level_size = 0;
2622 	u64 nums;
2623 
2624 	mutex_lock(&fs_info->qgroup_ioctl_lock);
2625 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2626 		goto out;
2627 
2628 	quota_root = fs_info->quota_root;
2629 	if (!quota_root) {
2630 		ret = -EINVAL;
2631 		goto out;
2632 	}
2633 
2634 	if (inherit) {
2635 		i_qgroups = (u64 *)(inherit + 1);
2636 		nums = inherit->num_qgroups + 2 * inherit->num_ref_copies +
2637 		       2 * inherit->num_excl_copies;
2638 		for (i = 0; i < nums; ++i) {
2639 			srcgroup = find_qgroup_rb(fs_info, *i_qgroups);
2640 
2641 			/*
2642 			 * Zero out invalid groups so we can ignore
2643 			 * them later.
2644 			 */
2645 			if (!srcgroup ||
2646 			    ((srcgroup->qgroupid >> 48) <= (objectid >> 48)))
2647 				*i_qgroups = 0ULL;
2648 
2649 			++i_qgroups;
2650 		}
2651 	}
2652 
2653 	/*
2654 	 * create a tracking group for the subvol itself
2655 	 */
2656 	ret = add_qgroup_item(trans, quota_root, objectid);
2657 	if (ret)
2658 		goto out;
2659 
2660 	/*
2661 	 * add qgroup to all inherited groups
2662 	 */
2663 	if (inherit) {
2664 		i_qgroups = (u64 *)(inherit + 1);
2665 		for (i = 0; i < inherit->num_qgroups; ++i, ++i_qgroups) {
2666 			if (*i_qgroups == 0)
2667 				continue;
2668 			ret = add_qgroup_relation_item(trans, objectid,
2669 						       *i_qgroups);
2670 			if (ret && ret != -EEXIST)
2671 				goto out;
2672 			ret = add_qgroup_relation_item(trans, *i_qgroups,
2673 						       objectid);
2674 			if (ret && ret != -EEXIST)
2675 				goto out;
2676 		}
2677 		ret = 0;
2678 	}
2679 
2680 
2681 	spin_lock(&fs_info->qgroup_lock);
2682 
2683 	dstgroup = add_qgroup_rb(fs_info, objectid);
2684 	if (IS_ERR(dstgroup)) {
2685 		ret = PTR_ERR(dstgroup);
2686 		goto unlock;
2687 	}
2688 
2689 	if (inherit && inherit->flags & BTRFS_QGROUP_INHERIT_SET_LIMITS) {
2690 		dstgroup->lim_flags = inherit->lim.flags;
2691 		dstgroup->max_rfer = inherit->lim.max_rfer;
2692 		dstgroup->max_excl = inherit->lim.max_excl;
2693 		dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
2694 		dstgroup->rsv_excl = inherit->lim.rsv_excl;
2695 
2696 		ret = update_qgroup_limit_item(trans, dstgroup);
2697 		if (ret) {
2698 			fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2699 			btrfs_info(fs_info,
2700 				   "unable to update quota limit for %llu",
2701 				   dstgroup->qgroupid);
2702 			goto unlock;
2703 		}
2704 	}
2705 
2706 	if (srcid) {
2707 		srcgroup = find_qgroup_rb(fs_info, srcid);
2708 		if (!srcgroup)
2709 			goto unlock;
2710 
2711 		/*
2712 		 * We call inherit after we clone the root in order to make sure
2713 		 * our counts don't go crazy, so at this point the only
2714 		 * difference between the two roots should be the root node.
2715 		 */
2716 		level_size = fs_info->nodesize;
2717 		dstgroup->rfer = srcgroup->rfer;
2718 		dstgroup->rfer_cmpr = srcgroup->rfer_cmpr;
2719 		dstgroup->excl = level_size;
2720 		dstgroup->excl_cmpr = level_size;
2721 		srcgroup->excl = level_size;
2722 		srcgroup->excl_cmpr = level_size;
2723 
2724 		/* inherit the limit info */
2725 		dstgroup->lim_flags = srcgroup->lim_flags;
2726 		dstgroup->max_rfer = srcgroup->max_rfer;
2727 		dstgroup->max_excl = srcgroup->max_excl;
2728 		dstgroup->rsv_rfer = srcgroup->rsv_rfer;
2729 		dstgroup->rsv_excl = srcgroup->rsv_excl;
2730 
2731 		qgroup_dirty(fs_info, dstgroup);
2732 		qgroup_dirty(fs_info, srcgroup);
2733 	}
2734 
2735 	if (!inherit)
2736 		goto unlock;
2737 
2738 	i_qgroups = (u64 *)(inherit + 1);
2739 	for (i = 0; i < inherit->num_qgroups; ++i) {
2740 		if (*i_qgroups) {
2741 			ret = add_relation_rb(fs_info, objectid, *i_qgroups);
2742 			if (ret)
2743 				goto unlock;
2744 		}
2745 		++i_qgroups;
2746 	}
2747 
2748 	for (i = 0; i <  inherit->num_ref_copies; ++i, i_qgroups += 2) {
2749 		struct btrfs_qgroup *src;
2750 		struct btrfs_qgroup *dst;
2751 
2752 		if (!i_qgroups[0] || !i_qgroups[1])
2753 			continue;
2754 
2755 		src = find_qgroup_rb(fs_info, i_qgroups[0]);
2756 		dst = find_qgroup_rb(fs_info, i_qgroups[1]);
2757 
2758 		if (!src || !dst) {
2759 			ret = -EINVAL;
2760 			goto unlock;
2761 		}
2762 
2763 		dst->rfer = src->rfer - level_size;
2764 		dst->rfer_cmpr = src->rfer_cmpr - level_size;
2765 	}
2766 	for (i = 0; i <  inherit->num_excl_copies; ++i, i_qgroups += 2) {
2767 		struct btrfs_qgroup *src;
2768 		struct btrfs_qgroup *dst;
2769 
2770 		if (!i_qgroups[0] || !i_qgroups[1])
2771 			continue;
2772 
2773 		src = find_qgroup_rb(fs_info, i_qgroups[0]);
2774 		dst = find_qgroup_rb(fs_info, i_qgroups[1]);
2775 
2776 		if (!src || !dst) {
2777 			ret = -EINVAL;
2778 			goto unlock;
2779 		}
2780 
2781 		dst->excl = src->excl + level_size;
2782 		dst->excl_cmpr = src->excl_cmpr + level_size;
2783 	}
2784 
2785 unlock:
2786 	spin_unlock(&fs_info->qgroup_lock);
2787 out:
2788 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
2789 	return ret;
2790 }
2791 
2792 /*
2793  * Two limits to commit transaction in advance.
2794  *
2795  * For RATIO, it will be 1/RATIO of the remaining limit as threshold.
2796  * For SIZE, it will be in byte unit as threshold.
2797  */
2798 #define QGROUP_FREE_RATIO		32
2799 #define QGROUP_FREE_SIZE		SZ_32M
2800 static bool qgroup_check_limits(struct btrfs_fs_info *fs_info,
2801 				const struct btrfs_qgroup *qg, u64 num_bytes)
2802 {
2803 	u64 free;
2804 	u64 threshold;
2805 
2806 	if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
2807 	    qgroup_rsv_total(qg) + (s64)qg->rfer + num_bytes > qg->max_rfer)
2808 		return false;
2809 
2810 	if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
2811 	    qgroup_rsv_total(qg) + (s64)qg->excl + num_bytes > qg->max_excl)
2812 		return false;
2813 
2814 	/*
2815 	 * Even if we passed the check, it's better to check if reservation
2816 	 * for meta_pertrans is pushing us near limit.
2817 	 * If there is too much pertrans reservation or it's near the limit,
2818 	 * let's try commit transaction to free some, using transaction_kthread
2819 	 */
2820 	if ((qg->lim_flags & (BTRFS_QGROUP_LIMIT_MAX_RFER |
2821 			      BTRFS_QGROUP_LIMIT_MAX_EXCL))) {
2822 		if (qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
2823 			free = qg->max_excl - qgroup_rsv_total(qg) - qg->excl;
2824 			threshold = min_t(u64, qg->max_excl / QGROUP_FREE_RATIO,
2825 					  QGROUP_FREE_SIZE);
2826 		} else {
2827 			free = qg->max_rfer - qgroup_rsv_total(qg) - qg->rfer;
2828 			threshold = min_t(u64, qg->max_rfer / QGROUP_FREE_RATIO,
2829 					  QGROUP_FREE_SIZE);
2830 		}
2831 
2832 		/*
2833 		 * Use transaction_kthread to commit transaction, so we no
2834 		 * longer need to bother nested transaction nor lock context.
2835 		 */
2836 		if (free < threshold)
2837 			btrfs_commit_transaction_locksafe(fs_info);
2838 	}
2839 
2840 	return true;
2841 }
2842 
2843 static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce,
2844 			  enum btrfs_qgroup_rsv_type type)
2845 {
2846 	struct btrfs_root *quota_root;
2847 	struct btrfs_qgroup *qgroup;
2848 	struct btrfs_fs_info *fs_info = root->fs_info;
2849 	u64 ref_root = root->root_key.objectid;
2850 	int ret = 0;
2851 	struct ulist_node *unode;
2852 	struct ulist_iterator uiter;
2853 
2854 	if (!is_fstree(ref_root))
2855 		return 0;
2856 
2857 	if (num_bytes == 0)
2858 		return 0;
2859 
2860 	if (test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags) &&
2861 	    capable(CAP_SYS_RESOURCE))
2862 		enforce = false;
2863 
2864 	spin_lock(&fs_info->qgroup_lock);
2865 	quota_root = fs_info->quota_root;
2866 	if (!quota_root)
2867 		goto out;
2868 
2869 	qgroup = find_qgroup_rb(fs_info, ref_root);
2870 	if (!qgroup)
2871 		goto out;
2872 
2873 	/*
2874 	 * in a first step, we check all affected qgroups if any limits would
2875 	 * be exceeded
2876 	 */
2877 	ulist_reinit(fs_info->qgroup_ulist);
2878 	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2879 			qgroup_to_aux(qgroup), GFP_ATOMIC);
2880 	if (ret < 0)
2881 		goto out;
2882 	ULIST_ITER_INIT(&uiter);
2883 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2884 		struct btrfs_qgroup *qg;
2885 		struct btrfs_qgroup_list *glist;
2886 
2887 		qg = unode_aux_to_qgroup(unode);
2888 
2889 		if (enforce && !qgroup_check_limits(fs_info, qg, num_bytes)) {
2890 			ret = -EDQUOT;
2891 			goto out;
2892 		}
2893 
2894 		list_for_each_entry(glist, &qg->groups, next_group) {
2895 			ret = ulist_add(fs_info->qgroup_ulist,
2896 					glist->group->qgroupid,
2897 					qgroup_to_aux(glist->group), GFP_ATOMIC);
2898 			if (ret < 0)
2899 				goto out;
2900 		}
2901 	}
2902 	ret = 0;
2903 	/*
2904 	 * no limits exceeded, now record the reservation into all qgroups
2905 	 */
2906 	ULIST_ITER_INIT(&uiter);
2907 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2908 		struct btrfs_qgroup *qg;
2909 
2910 		qg = unode_aux_to_qgroup(unode);
2911 
2912 		qgroup_rsv_add(fs_info, qg, num_bytes, type);
2913 	}
2914 
2915 out:
2916 	spin_unlock(&fs_info->qgroup_lock);
2917 	return ret;
2918 }
2919 
2920 /*
2921  * Free @num_bytes of reserved space with @type for qgroup.  (Normally level 0
2922  * qgroup).
2923  *
2924  * Will handle all higher level qgroup too.
2925  *
2926  * NOTE: If @num_bytes is (u64)-1, this means to free all bytes of this qgroup.
2927  * This special case is only used for META_PERTRANS type.
2928  */
2929 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
2930 			       u64 ref_root, u64 num_bytes,
2931 			       enum btrfs_qgroup_rsv_type type)
2932 {
2933 	struct btrfs_root *quota_root;
2934 	struct btrfs_qgroup *qgroup;
2935 	struct ulist_node *unode;
2936 	struct ulist_iterator uiter;
2937 	int ret = 0;
2938 
2939 	if (!is_fstree(ref_root))
2940 		return;
2941 
2942 	if (num_bytes == 0)
2943 		return;
2944 
2945 	if (num_bytes == (u64)-1 && type != BTRFS_QGROUP_RSV_META_PERTRANS) {
2946 		WARN(1, "%s: Invalid type to free", __func__);
2947 		return;
2948 	}
2949 	spin_lock(&fs_info->qgroup_lock);
2950 
2951 	quota_root = fs_info->quota_root;
2952 	if (!quota_root)
2953 		goto out;
2954 
2955 	qgroup = find_qgroup_rb(fs_info, ref_root);
2956 	if (!qgroup)
2957 		goto out;
2958 
2959 	if (num_bytes == (u64)-1)
2960 		/*
2961 		 * We're freeing all pertrans rsv, get reserved value from
2962 		 * level 0 qgroup as real num_bytes to free.
2963 		 */
2964 		num_bytes = qgroup->rsv.values[type];
2965 
2966 	ulist_reinit(fs_info->qgroup_ulist);
2967 	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2968 			qgroup_to_aux(qgroup), GFP_ATOMIC);
2969 	if (ret < 0)
2970 		goto out;
2971 	ULIST_ITER_INIT(&uiter);
2972 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2973 		struct btrfs_qgroup *qg;
2974 		struct btrfs_qgroup_list *glist;
2975 
2976 		qg = unode_aux_to_qgroup(unode);
2977 
2978 		qgroup_rsv_release(fs_info, qg, num_bytes, type);
2979 
2980 		list_for_each_entry(glist, &qg->groups, next_group) {
2981 			ret = ulist_add(fs_info->qgroup_ulist,
2982 					glist->group->qgroupid,
2983 					qgroup_to_aux(glist->group), GFP_ATOMIC);
2984 			if (ret < 0)
2985 				goto out;
2986 		}
2987 	}
2988 
2989 out:
2990 	spin_unlock(&fs_info->qgroup_lock);
2991 }
2992 
2993 /*
2994  * Check if the leaf is the last leaf. Which means all node pointers
2995  * are at their last position.
2996  */
2997 static bool is_last_leaf(struct btrfs_path *path)
2998 {
2999 	int i;
3000 
3001 	for (i = 1; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
3002 		if (path->slots[i] != btrfs_header_nritems(path->nodes[i]) - 1)
3003 			return false;
3004 	}
3005 	return true;
3006 }
3007 
3008 /*
3009  * returns < 0 on error, 0 when more leafs are to be scanned.
3010  * returns 1 when done.
3011  */
3012 static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
3013 			      struct btrfs_path *path)
3014 {
3015 	struct btrfs_fs_info *fs_info = trans->fs_info;
3016 	struct btrfs_key found;
3017 	struct extent_buffer *scratch_leaf = NULL;
3018 	struct ulist *roots = NULL;
3019 	u64 num_bytes;
3020 	bool done;
3021 	int slot;
3022 	int ret;
3023 
3024 	mutex_lock(&fs_info->qgroup_rescan_lock);
3025 	ret = btrfs_search_slot_for_read(fs_info->extent_root,
3026 					 &fs_info->qgroup_rescan_progress,
3027 					 path, 1, 0);
3028 
3029 	btrfs_debug(fs_info,
3030 		"current progress key (%llu %u %llu), search_slot ret %d",
3031 		fs_info->qgroup_rescan_progress.objectid,
3032 		fs_info->qgroup_rescan_progress.type,
3033 		fs_info->qgroup_rescan_progress.offset, ret);
3034 
3035 	if (ret) {
3036 		/*
3037 		 * The rescan is about to end, we will not be scanning any
3038 		 * further blocks. We cannot unset the RESCAN flag here, because
3039 		 * we want to commit the transaction if everything went well.
3040 		 * To make the live accounting work in this phase, we set our
3041 		 * scan progress pointer such that every real extent objectid
3042 		 * will be smaller.
3043 		 */
3044 		fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3045 		btrfs_release_path(path);
3046 		mutex_unlock(&fs_info->qgroup_rescan_lock);
3047 		return ret;
3048 	}
3049 	done = is_last_leaf(path);
3050 
3051 	btrfs_item_key_to_cpu(path->nodes[0], &found,
3052 			      btrfs_header_nritems(path->nodes[0]) - 1);
3053 	fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
3054 
3055 	scratch_leaf = btrfs_clone_extent_buffer(path->nodes[0]);
3056 	if (!scratch_leaf) {
3057 		ret = -ENOMEM;
3058 		mutex_unlock(&fs_info->qgroup_rescan_lock);
3059 		goto out;
3060 	}
3061 	slot = path->slots[0];
3062 	btrfs_release_path(path);
3063 	mutex_unlock(&fs_info->qgroup_rescan_lock);
3064 
3065 	for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
3066 		btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
3067 		if (found.type != BTRFS_EXTENT_ITEM_KEY &&
3068 		    found.type != BTRFS_METADATA_ITEM_KEY)
3069 			continue;
3070 		if (found.type == BTRFS_METADATA_ITEM_KEY)
3071 			num_bytes = fs_info->nodesize;
3072 		else
3073 			num_bytes = found.offset;
3074 
3075 		ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0,
3076 					   &roots, false);
3077 		if (ret < 0)
3078 			goto out;
3079 		/* For rescan, just pass old_roots as NULL */
3080 		ret = btrfs_qgroup_account_extent(trans, found.objectid,
3081 						  num_bytes, NULL, roots);
3082 		if (ret < 0)
3083 			goto out;
3084 	}
3085 out:
3086 	if (scratch_leaf)
3087 		free_extent_buffer(scratch_leaf);
3088 
3089 	if (done && !ret) {
3090 		ret = 1;
3091 		fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3092 	}
3093 	return ret;
3094 }
3095 
3096 static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
3097 {
3098 	struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
3099 						     qgroup_rescan_work);
3100 	struct btrfs_path *path;
3101 	struct btrfs_trans_handle *trans = NULL;
3102 	int err = -ENOMEM;
3103 	int ret = 0;
3104 
3105 	path = btrfs_alloc_path();
3106 	if (!path)
3107 		goto out;
3108 	/*
3109 	 * Rescan should only search for commit root, and any later difference
3110 	 * should be recorded by qgroup
3111 	 */
3112 	path->search_commit_root = 1;
3113 	path->skip_locking = 1;
3114 
3115 	err = 0;
3116 	while (!err && !btrfs_fs_closing(fs_info)) {
3117 		trans = btrfs_start_transaction(fs_info->fs_root, 0);
3118 		if (IS_ERR(trans)) {
3119 			err = PTR_ERR(trans);
3120 			break;
3121 		}
3122 		if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
3123 			err = -EINTR;
3124 		} else {
3125 			err = qgroup_rescan_leaf(trans, path);
3126 		}
3127 		if (err > 0)
3128 			btrfs_commit_transaction(trans);
3129 		else
3130 			btrfs_end_transaction(trans);
3131 	}
3132 
3133 out:
3134 	btrfs_free_path(path);
3135 
3136 	mutex_lock(&fs_info->qgroup_rescan_lock);
3137 	if (!btrfs_fs_closing(fs_info))
3138 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3139 
3140 	if (err > 0 &&
3141 	    fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
3142 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3143 	} else if (err < 0) {
3144 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3145 	}
3146 	mutex_unlock(&fs_info->qgroup_rescan_lock);
3147 
3148 	/*
3149 	 * only update status, since the previous part has already updated the
3150 	 * qgroup info.
3151 	 */
3152 	trans = btrfs_start_transaction(fs_info->quota_root, 1);
3153 	if (IS_ERR(trans)) {
3154 		err = PTR_ERR(trans);
3155 		btrfs_err(fs_info,
3156 			  "fail to start transaction for status update: %d",
3157 			  err);
3158 		goto done;
3159 	}
3160 	ret = update_qgroup_status_item(trans);
3161 	if (ret < 0) {
3162 		err = ret;
3163 		btrfs_err(fs_info, "fail to update qgroup status: %d", err);
3164 	}
3165 	btrfs_end_transaction(trans);
3166 
3167 	if (btrfs_fs_closing(fs_info)) {
3168 		btrfs_info(fs_info, "qgroup scan paused");
3169 	} else if (err >= 0) {
3170 		btrfs_info(fs_info, "qgroup scan completed%s",
3171 			err > 0 ? " (inconsistency flag cleared)" : "");
3172 	} else {
3173 		btrfs_err(fs_info, "qgroup scan failed with %d", err);
3174 	}
3175 
3176 done:
3177 	mutex_lock(&fs_info->qgroup_rescan_lock);
3178 	fs_info->qgroup_rescan_running = false;
3179 	mutex_unlock(&fs_info->qgroup_rescan_lock);
3180 	complete_all(&fs_info->qgroup_rescan_completion);
3181 }
3182 
3183 /*
3184  * Checks that (a) no rescan is running and (b) quota is enabled. Allocates all
3185  * memory required for the rescan context.
3186  */
3187 static int
3188 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
3189 		   int init_flags)
3190 {
3191 	int ret = 0;
3192 
3193 	if (!init_flags) {
3194 		/* we're resuming qgroup rescan at mount time */
3195 		if (!(fs_info->qgroup_flags &
3196 		      BTRFS_QGROUP_STATUS_FLAG_RESCAN)) {
3197 			btrfs_warn(fs_info,
3198 			"qgroup rescan init failed, qgroup is not enabled");
3199 			ret = -EINVAL;
3200 		} else if (!(fs_info->qgroup_flags &
3201 			     BTRFS_QGROUP_STATUS_FLAG_ON)) {
3202 			btrfs_warn(fs_info,
3203 			"qgroup rescan init failed, qgroup rescan is not queued");
3204 			ret = -EINVAL;
3205 		}
3206 
3207 		if (ret)
3208 			return ret;
3209 	}
3210 
3211 	mutex_lock(&fs_info->qgroup_rescan_lock);
3212 	spin_lock(&fs_info->qgroup_lock);
3213 
3214 	if (init_flags) {
3215 		if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
3216 			btrfs_warn(fs_info,
3217 				   "qgroup rescan is already in progress");
3218 			ret = -EINPROGRESS;
3219 		} else if (!(fs_info->qgroup_flags &
3220 			     BTRFS_QGROUP_STATUS_FLAG_ON)) {
3221 			btrfs_warn(fs_info,
3222 			"qgroup rescan init failed, qgroup is not enabled");
3223 			ret = -EINVAL;
3224 		}
3225 
3226 		if (ret) {
3227 			spin_unlock(&fs_info->qgroup_lock);
3228 			mutex_unlock(&fs_info->qgroup_rescan_lock);
3229 			return ret;
3230 		}
3231 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3232 	}
3233 
3234 	memset(&fs_info->qgroup_rescan_progress, 0,
3235 		sizeof(fs_info->qgroup_rescan_progress));
3236 	fs_info->qgroup_rescan_progress.objectid = progress_objectid;
3237 	init_completion(&fs_info->qgroup_rescan_completion);
3238 	fs_info->qgroup_rescan_running = true;
3239 
3240 	spin_unlock(&fs_info->qgroup_lock);
3241 	mutex_unlock(&fs_info->qgroup_rescan_lock);
3242 
3243 	memset(&fs_info->qgroup_rescan_work, 0,
3244 	       sizeof(fs_info->qgroup_rescan_work));
3245 	btrfs_init_work(&fs_info->qgroup_rescan_work,
3246 			btrfs_qgroup_rescan_helper,
3247 			btrfs_qgroup_rescan_worker, NULL, NULL);
3248 	return 0;
3249 }
3250 
3251 static void
3252 qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info)
3253 {
3254 	struct rb_node *n;
3255 	struct btrfs_qgroup *qgroup;
3256 
3257 	spin_lock(&fs_info->qgroup_lock);
3258 	/* clear all current qgroup tracking information */
3259 	for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
3260 		qgroup = rb_entry(n, struct btrfs_qgroup, node);
3261 		qgroup->rfer = 0;
3262 		qgroup->rfer_cmpr = 0;
3263 		qgroup->excl = 0;
3264 		qgroup->excl_cmpr = 0;
3265 		qgroup_dirty(fs_info, qgroup);
3266 	}
3267 	spin_unlock(&fs_info->qgroup_lock);
3268 }
3269 
3270 int
3271 btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
3272 {
3273 	int ret = 0;
3274 	struct btrfs_trans_handle *trans;
3275 
3276 	ret = qgroup_rescan_init(fs_info, 0, 1);
3277 	if (ret)
3278 		return ret;
3279 
3280 	/*
3281 	 * We have set the rescan_progress to 0, which means no more
3282 	 * delayed refs will be accounted by btrfs_qgroup_account_ref.
3283 	 * However, btrfs_qgroup_account_ref may be right after its call
3284 	 * to btrfs_find_all_roots, in which case it would still do the
3285 	 * accounting.
3286 	 * To solve this, we're committing the transaction, which will
3287 	 * ensure we run all delayed refs and only after that, we are
3288 	 * going to clear all tracking information for a clean start.
3289 	 */
3290 
3291 	trans = btrfs_join_transaction(fs_info->fs_root);
3292 	if (IS_ERR(trans)) {
3293 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3294 		return PTR_ERR(trans);
3295 	}
3296 	ret = btrfs_commit_transaction(trans);
3297 	if (ret) {
3298 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3299 		return ret;
3300 	}
3301 
3302 	qgroup_rescan_zero_tracking(fs_info);
3303 
3304 	btrfs_queue_work(fs_info->qgroup_rescan_workers,
3305 			 &fs_info->qgroup_rescan_work);
3306 
3307 	return 0;
3308 }
3309 
3310 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
3311 				     bool interruptible)
3312 {
3313 	int running;
3314 	int ret = 0;
3315 
3316 	mutex_lock(&fs_info->qgroup_rescan_lock);
3317 	spin_lock(&fs_info->qgroup_lock);
3318 	running = fs_info->qgroup_rescan_running;
3319 	spin_unlock(&fs_info->qgroup_lock);
3320 	mutex_unlock(&fs_info->qgroup_rescan_lock);
3321 
3322 	if (!running)
3323 		return 0;
3324 
3325 	if (interruptible)
3326 		ret = wait_for_completion_interruptible(
3327 					&fs_info->qgroup_rescan_completion);
3328 	else
3329 		wait_for_completion(&fs_info->qgroup_rescan_completion);
3330 
3331 	return ret;
3332 }
3333 
3334 /*
3335  * this is only called from open_ctree where we're still single threaded, thus
3336  * locking is omitted here.
3337  */
3338 void
3339 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
3340 {
3341 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
3342 		btrfs_queue_work(fs_info->qgroup_rescan_workers,
3343 				 &fs_info->qgroup_rescan_work);
3344 }
3345 
3346 /*
3347  * Reserve qgroup space for range [start, start + len).
3348  *
3349  * This function will either reserve space from related qgroups or doing
3350  * nothing if the range is already reserved.
3351  *
3352  * Return 0 for successful reserve
3353  * Return <0 for error (including -EQUOT)
3354  *
3355  * NOTE: this function may sleep for memory allocation.
3356  *       if btrfs_qgroup_reserve_data() is called multiple times with
3357  *       same @reserved, caller must ensure when error happens it's OK
3358  *       to free *ALL* reserved space.
3359  */
3360 int btrfs_qgroup_reserve_data(struct inode *inode,
3361 			struct extent_changeset **reserved_ret, u64 start,
3362 			u64 len)
3363 {
3364 	struct btrfs_root *root = BTRFS_I(inode)->root;
3365 	struct ulist_node *unode;
3366 	struct ulist_iterator uiter;
3367 	struct extent_changeset *reserved;
3368 	u64 orig_reserved;
3369 	u64 to_reserve;
3370 	int ret;
3371 
3372 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags) ||
3373 	    !is_fstree(root->root_key.objectid) || len == 0)
3374 		return 0;
3375 
3376 	/* @reserved parameter is mandatory for qgroup */
3377 	if (WARN_ON(!reserved_ret))
3378 		return -EINVAL;
3379 	if (!*reserved_ret) {
3380 		*reserved_ret = extent_changeset_alloc();
3381 		if (!*reserved_ret)
3382 			return -ENOMEM;
3383 	}
3384 	reserved = *reserved_ret;
3385 	/* Record already reserved space */
3386 	orig_reserved = reserved->bytes_changed;
3387 	ret = set_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
3388 			start + len -1, EXTENT_QGROUP_RESERVED, reserved);
3389 
3390 	/* Newly reserved space */
3391 	to_reserve = reserved->bytes_changed - orig_reserved;
3392 	trace_btrfs_qgroup_reserve_data(inode, start, len,
3393 					to_reserve, QGROUP_RESERVE);
3394 	if (ret < 0)
3395 		goto cleanup;
3396 	ret = qgroup_reserve(root, to_reserve, true, BTRFS_QGROUP_RSV_DATA);
3397 	if (ret < 0)
3398 		goto cleanup;
3399 
3400 	return ret;
3401 
3402 cleanup:
3403 	/* cleanup *ALL* already reserved ranges */
3404 	ULIST_ITER_INIT(&uiter);
3405 	while ((unode = ulist_next(&reserved->range_changed, &uiter)))
3406 		clear_extent_bit(&BTRFS_I(inode)->io_tree, unode->val,
3407 				 unode->aux, EXTENT_QGROUP_RESERVED, 0, 0, NULL);
3408 	extent_changeset_release(reserved);
3409 	return ret;
3410 }
3411 
3412 /* Free ranges specified by @reserved, normally in error path */
3413 static int qgroup_free_reserved_data(struct inode *inode,
3414 			struct extent_changeset *reserved, u64 start, u64 len)
3415 {
3416 	struct btrfs_root *root = BTRFS_I(inode)->root;
3417 	struct ulist_node *unode;
3418 	struct ulist_iterator uiter;
3419 	struct extent_changeset changeset;
3420 	int freed = 0;
3421 	int ret;
3422 
3423 	extent_changeset_init(&changeset);
3424 	len = round_up(start + len, root->fs_info->sectorsize);
3425 	start = round_down(start, root->fs_info->sectorsize);
3426 
3427 	ULIST_ITER_INIT(&uiter);
3428 	while ((unode = ulist_next(&reserved->range_changed, &uiter))) {
3429 		u64 range_start = unode->val;
3430 		/* unode->aux is the inclusive end */
3431 		u64 range_len = unode->aux - range_start + 1;
3432 		u64 free_start;
3433 		u64 free_len;
3434 
3435 		extent_changeset_release(&changeset);
3436 
3437 		/* Only free range in range [start, start + len) */
3438 		if (range_start >= start + len ||
3439 		    range_start + range_len <= start)
3440 			continue;
3441 		free_start = max(range_start, start);
3442 		free_len = min(start + len, range_start + range_len) -
3443 			   free_start;
3444 		/*
3445 		 * TODO: To also modify reserved->ranges_reserved to reflect
3446 		 * the modification.
3447 		 *
3448 		 * However as long as we free qgroup reserved according to
3449 		 * EXTENT_QGROUP_RESERVED, we won't double free.
3450 		 * So not need to rush.
3451 		 */
3452 		ret = clear_record_extent_bits(&BTRFS_I(inode)->io_failure_tree,
3453 				free_start, free_start + free_len - 1,
3454 				EXTENT_QGROUP_RESERVED, &changeset);
3455 		if (ret < 0)
3456 			goto out;
3457 		freed += changeset.bytes_changed;
3458 	}
3459 	btrfs_qgroup_free_refroot(root->fs_info, root->root_key.objectid, freed,
3460 				  BTRFS_QGROUP_RSV_DATA);
3461 	ret = freed;
3462 out:
3463 	extent_changeset_release(&changeset);
3464 	return ret;
3465 }
3466 
3467 static int __btrfs_qgroup_release_data(struct inode *inode,
3468 			struct extent_changeset *reserved, u64 start, u64 len,
3469 			int free)
3470 {
3471 	struct extent_changeset changeset;
3472 	int trace_op = QGROUP_RELEASE;
3473 	int ret;
3474 
3475 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED,
3476 		      &BTRFS_I(inode)->root->fs_info->flags))
3477 		return 0;
3478 
3479 	/* In release case, we shouldn't have @reserved */
3480 	WARN_ON(!free && reserved);
3481 	if (free && reserved)
3482 		return qgroup_free_reserved_data(inode, reserved, start, len);
3483 	extent_changeset_init(&changeset);
3484 	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
3485 			start + len -1, EXTENT_QGROUP_RESERVED, &changeset);
3486 	if (ret < 0)
3487 		goto out;
3488 
3489 	if (free)
3490 		trace_op = QGROUP_FREE;
3491 	trace_btrfs_qgroup_release_data(inode, start, len,
3492 					changeset.bytes_changed, trace_op);
3493 	if (free)
3494 		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3495 				BTRFS_I(inode)->root->root_key.objectid,
3496 				changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3497 	ret = changeset.bytes_changed;
3498 out:
3499 	extent_changeset_release(&changeset);
3500 	return ret;
3501 }
3502 
3503 /*
3504  * Free a reserved space range from io_tree and related qgroups
3505  *
3506  * Should be called when a range of pages get invalidated before reaching disk.
3507  * Or for error cleanup case.
3508  * if @reserved is given, only reserved range in [@start, @start + @len) will
3509  * be freed.
3510  *
3511  * For data written to disk, use btrfs_qgroup_release_data().
3512  *
3513  * NOTE: This function may sleep for memory allocation.
3514  */
3515 int btrfs_qgroup_free_data(struct inode *inode,
3516 			struct extent_changeset *reserved, u64 start, u64 len)
3517 {
3518 	return __btrfs_qgroup_release_data(inode, reserved, start, len, 1);
3519 }
3520 
3521 /*
3522  * Release a reserved space range from io_tree only.
3523  *
3524  * Should be called when a range of pages get written to disk and corresponding
3525  * FILE_EXTENT is inserted into corresponding root.
3526  *
3527  * Since new qgroup accounting framework will only update qgroup numbers at
3528  * commit_transaction() time, its reserved space shouldn't be freed from
3529  * related qgroups.
3530  *
3531  * But we should release the range from io_tree, to allow further write to be
3532  * COWed.
3533  *
3534  * NOTE: This function may sleep for memory allocation.
3535  */
3536 int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len)
3537 {
3538 	return __btrfs_qgroup_release_data(inode, NULL, start, len, 0);
3539 }
3540 
3541 static void add_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3542 			      enum btrfs_qgroup_rsv_type type)
3543 {
3544 	if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3545 	    type != BTRFS_QGROUP_RSV_META_PERTRANS)
3546 		return;
3547 	if (num_bytes == 0)
3548 		return;
3549 
3550 	spin_lock(&root->qgroup_meta_rsv_lock);
3551 	if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
3552 		root->qgroup_meta_rsv_prealloc += num_bytes;
3553 	else
3554 		root->qgroup_meta_rsv_pertrans += num_bytes;
3555 	spin_unlock(&root->qgroup_meta_rsv_lock);
3556 }
3557 
3558 static int sub_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3559 			     enum btrfs_qgroup_rsv_type type)
3560 {
3561 	if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3562 	    type != BTRFS_QGROUP_RSV_META_PERTRANS)
3563 		return 0;
3564 	if (num_bytes == 0)
3565 		return 0;
3566 
3567 	spin_lock(&root->qgroup_meta_rsv_lock);
3568 	if (type == BTRFS_QGROUP_RSV_META_PREALLOC) {
3569 		num_bytes = min_t(u64, root->qgroup_meta_rsv_prealloc,
3570 				  num_bytes);
3571 		root->qgroup_meta_rsv_prealloc -= num_bytes;
3572 	} else {
3573 		num_bytes = min_t(u64, root->qgroup_meta_rsv_pertrans,
3574 				  num_bytes);
3575 		root->qgroup_meta_rsv_pertrans -= num_bytes;
3576 	}
3577 	spin_unlock(&root->qgroup_meta_rsv_lock);
3578 	return num_bytes;
3579 }
3580 
3581 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
3582 				enum btrfs_qgroup_rsv_type type, bool enforce)
3583 {
3584 	struct btrfs_fs_info *fs_info = root->fs_info;
3585 	int ret;
3586 
3587 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3588 	    !is_fstree(root->root_key.objectid) || num_bytes == 0)
3589 		return 0;
3590 
3591 	BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3592 	trace_qgroup_meta_reserve(root, type, (s64)num_bytes);
3593 	ret = qgroup_reserve(root, num_bytes, enforce, type);
3594 	if (ret < 0)
3595 		return ret;
3596 	/*
3597 	 * Record what we have reserved into root.
3598 	 *
3599 	 * To avoid quota disabled->enabled underflow.
3600 	 * In that case, we may try to free space we haven't reserved
3601 	 * (since quota was disabled), so record what we reserved into root.
3602 	 * And ensure later release won't underflow this number.
3603 	 */
3604 	add_root_meta_rsv(root, num_bytes, type);
3605 	return ret;
3606 }
3607 
3608 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root)
3609 {
3610 	struct btrfs_fs_info *fs_info = root->fs_info;
3611 
3612 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3613 	    !is_fstree(root->root_key.objectid))
3614 		return;
3615 
3616 	/* TODO: Update trace point to handle such free */
3617 	trace_qgroup_meta_free_all_pertrans(root);
3618 	/* Special value -1 means to free all reserved space */
3619 	btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid, (u64)-1,
3620 				  BTRFS_QGROUP_RSV_META_PERTRANS);
3621 }
3622 
3623 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
3624 			      enum btrfs_qgroup_rsv_type type)
3625 {
3626 	struct btrfs_fs_info *fs_info = root->fs_info;
3627 
3628 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3629 	    !is_fstree(root->root_key.objectid))
3630 		return;
3631 
3632 	/*
3633 	 * reservation for META_PREALLOC can happen before quota is enabled,
3634 	 * which can lead to underflow.
3635 	 * Here ensure we will only free what we really have reserved.
3636 	 */
3637 	num_bytes = sub_root_meta_rsv(root, num_bytes, type);
3638 	BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3639 	trace_qgroup_meta_reserve(root, type, -(s64)num_bytes);
3640 	btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
3641 				  num_bytes, type);
3642 }
3643 
3644 static void qgroup_convert_meta(struct btrfs_fs_info *fs_info, u64 ref_root,
3645 				int num_bytes)
3646 {
3647 	struct btrfs_root *quota_root = fs_info->quota_root;
3648 	struct btrfs_qgroup *qgroup;
3649 	struct ulist_node *unode;
3650 	struct ulist_iterator uiter;
3651 	int ret = 0;
3652 
3653 	if (num_bytes == 0)
3654 		return;
3655 	if (!quota_root)
3656 		return;
3657 
3658 	spin_lock(&fs_info->qgroup_lock);
3659 	qgroup = find_qgroup_rb(fs_info, ref_root);
3660 	if (!qgroup)
3661 		goto out;
3662 	ulist_reinit(fs_info->qgroup_ulist);
3663 	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
3664 		       qgroup_to_aux(qgroup), GFP_ATOMIC);
3665 	if (ret < 0)
3666 		goto out;
3667 	ULIST_ITER_INIT(&uiter);
3668 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
3669 		struct btrfs_qgroup *qg;
3670 		struct btrfs_qgroup_list *glist;
3671 
3672 		qg = unode_aux_to_qgroup(unode);
3673 
3674 		qgroup_rsv_release(fs_info, qg, num_bytes,
3675 				BTRFS_QGROUP_RSV_META_PREALLOC);
3676 		qgroup_rsv_add(fs_info, qg, num_bytes,
3677 				BTRFS_QGROUP_RSV_META_PERTRANS);
3678 		list_for_each_entry(glist, &qg->groups, next_group) {
3679 			ret = ulist_add(fs_info->qgroup_ulist,
3680 					glist->group->qgroupid,
3681 					qgroup_to_aux(glist->group), GFP_ATOMIC);
3682 			if (ret < 0)
3683 				goto out;
3684 		}
3685 	}
3686 out:
3687 	spin_unlock(&fs_info->qgroup_lock);
3688 }
3689 
3690 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes)
3691 {
3692 	struct btrfs_fs_info *fs_info = root->fs_info;
3693 
3694 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3695 	    !is_fstree(root->root_key.objectid))
3696 		return;
3697 	/* Same as btrfs_qgroup_free_meta_prealloc() */
3698 	num_bytes = sub_root_meta_rsv(root, num_bytes,
3699 				      BTRFS_QGROUP_RSV_META_PREALLOC);
3700 	trace_qgroup_meta_convert(root, num_bytes);
3701 	qgroup_convert_meta(fs_info, root->root_key.objectid, num_bytes);
3702 }
3703 
3704 /*
3705  * Check qgroup reserved space leaking, normally at destroy inode
3706  * time
3707  */
3708 void btrfs_qgroup_check_reserved_leak(struct inode *inode)
3709 {
3710 	struct extent_changeset changeset;
3711 	struct ulist_node *unode;
3712 	struct ulist_iterator iter;
3713 	int ret;
3714 
3715 	extent_changeset_init(&changeset);
3716 	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, 0, (u64)-1,
3717 			EXTENT_QGROUP_RESERVED, &changeset);
3718 
3719 	WARN_ON(ret < 0);
3720 	if (WARN_ON(changeset.bytes_changed)) {
3721 		ULIST_ITER_INIT(&iter);
3722 		while ((unode = ulist_next(&changeset.range_changed, &iter))) {
3723 			btrfs_warn(BTRFS_I(inode)->root->fs_info,
3724 				"leaking qgroup reserved space, ino: %lu, start: %llu, end: %llu",
3725 				inode->i_ino, unode->val, unode->aux);
3726 		}
3727 		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3728 				BTRFS_I(inode)->root->root_key.objectid,
3729 				changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3730 
3731 	}
3732 	extent_changeset_release(&changeset);
3733 }
3734 
3735 void btrfs_qgroup_init_swapped_blocks(
3736 	struct btrfs_qgroup_swapped_blocks *swapped_blocks)
3737 {
3738 	int i;
3739 
3740 	spin_lock_init(&swapped_blocks->lock);
3741 	for (i = 0; i < BTRFS_MAX_LEVEL; i++)
3742 		swapped_blocks->blocks[i] = RB_ROOT;
3743 	swapped_blocks->swapped = false;
3744 }
3745 
3746 /*
3747  * Delete all swapped blocks record of @root.
3748  * Every record here means we skipped a full subtree scan for qgroup.
3749  *
3750  * Gets called when committing one transaction.
3751  */
3752 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root)
3753 {
3754 	struct btrfs_qgroup_swapped_blocks *swapped_blocks;
3755 	int i;
3756 
3757 	swapped_blocks = &root->swapped_blocks;
3758 
3759 	spin_lock(&swapped_blocks->lock);
3760 	if (!swapped_blocks->swapped)
3761 		goto out;
3762 	for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3763 		struct rb_root *cur_root = &swapped_blocks->blocks[i];
3764 		struct btrfs_qgroup_swapped_block *entry;
3765 		struct btrfs_qgroup_swapped_block *next;
3766 
3767 		rbtree_postorder_for_each_entry_safe(entry, next, cur_root,
3768 						     node)
3769 			kfree(entry);
3770 		swapped_blocks->blocks[i] = RB_ROOT;
3771 	}
3772 	swapped_blocks->swapped = false;
3773 out:
3774 	spin_unlock(&swapped_blocks->lock);
3775 }
3776 
3777 /*
3778  * Add subtree roots record into @subvol_root.
3779  *
3780  * @subvol_root:	tree root of the subvolume tree get swapped
3781  * @bg:			block group under balance
3782  * @subvol_parent/slot:	pointer to the subtree root in subvolume tree
3783  * @reloc_parent/slot:	pointer to the subtree root in reloc tree
3784  *			BOTH POINTERS ARE BEFORE TREE SWAP
3785  * @last_snapshot:	last snapshot generation of the subvolume tree
3786  */
3787 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
3788 		struct btrfs_root *subvol_root,
3789 		struct btrfs_block_group_cache *bg,
3790 		struct extent_buffer *subvol_parent, int subvol_slot,
3791 		struct extent_buffer *reloc_parent, int reloc_slot,
3792 		u64 last_snapshot)
3793 {
3794 	struct btrfs_fs_info *fs_info = subvol_root->fs_info;
3795 	struct btrfs_qgroup_swapped_blocks *blocks = &subvol_root->swapped_blocks;
3796 	struct btrfs_qgroup_swapped_block *block;
3797 	struct rb_node **cur;
3798 	struct rb_node *parent = NULL;
3799 	int level = btrfs_header_level(subvol_parent) - 1;
3800 	int ret = 0;
3801 
3802 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
3803 		return 0;
3804 
3805 	if (btrfs_node_ptr_generation(subvol_parent, subvol_slot) >
3806 	    btrfs_node_ptr_generation(reloc_parent, reloc_slot)) {
3807 		btrfs_err_rl(fs_info,
3808 		"%s: bad parameter order, subvol_gen=%llu reloc_gen=%llu",
3809 			__func__,
3810 			btrfs_node_ptr_generation(subvol_parent, subvol_slot),
3811 			btrfs_node_ptr_generation(reloc_parent, reloc_slot));
3812 		return -EUCLEAN;
3813 	}
3814 
3815 	block = kmalloc(sizeof(*block), GFP_NOFS);
3816 	if (!block) {
3817 		ret = -ENOMEM;
3818 		goto out;
3819 	}
3820 
3821 	/*
3822 	 * @reloc_parent/slot is still before swap, while @block is going to
3823 	 * record the bytenr after swap, so we do the swap here.
3824 	 */
3825 	block->subvol_bytenr = btrfs_node_blockptr(reloc_parent, reloc_slot);
3826 	block->subvol_generation = btrfs_node_ptr_generation(reloc_parent,
3827 							     reloc_slot);
3828 	block->reloc_bytenr = btrfs_node_blockptr(subvol_parent, subvol_slot);
3829 	block->reloc_generation = btrfs_node_ptr_generation(subvol_parent,
3830 							    subvol_slot);
3831 	block->last_snapshot = last_snapshot;
3832 	block->level = level;
3833 
3834 	/*
3835 	 * If we have bg == NULL, we're called from btrfs_recover_relocation(),
3836 	 * no one else can modify tree blocks thus we qgroup will not change
3837 	 * no matter the value of trace_leaf.
3838 	 */
3839 	if (bg && bg->flags & BTRFS_BLOCK_GROUP_DATA)
3840 		block->trace_leaf = true;
3841 	else
3842 		block->trace_leaf = false;
3843 	btrfs_node_key_to_cpu(reloc_parent, &block->first_key, reloc_slot);
3844 
3845 	/* Insert @block into @blocks */
3846 	spin_lock(&blocks->lock);
3847 	cur = &blocks->blocks[level].rb_node;
3848 	while (*cur) {
3849 		struct btrfs_qgroup_swapped_block *entry;
3850 
3851 		parent = *cur;
3852 		entry = rb_entry(parent, struct btrfs_qgroup_swapped_block,
3853 				 node);
3854 
3855 		if (entry->subvol_bytenr < block->subvol_bytenr) {
3856 			cur = &(*cur)->rb_left;
3857 		} else if (entry->subvol_bytenr > block->subvol_bytenr) {
3858 			cur = &(*cur)->rb_right;
3859 		} else {
3860 			if (entry->subvol_generation !=
3861 					block->subvol_generation ||
3862 			    entry->reloc_bytenr != block->reloc_bytenr ||
3863 			    entry->reloc_generation !=
3864 					block->reloc_generation) {
3865 				/*
3866 				 * Duplicated but mismatch entry found.
3867 				 * Shouldn't happen.
3868 				 *
3869 				 * Marking qgroup inconsistent should be enough
3870 				 * for end users.
3871 				 */
3872 				WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
3873 				ret = -EEXIST;
3874 			}
3875 			kfree(block);
3876 			goto out_unlock;
3877 		}
3878 	}
3879 	rb_link_node(&block->node, parent, cur);
3880 	rb_insert_color(&block->node, &blocks->blocks[level]);
3881 	blocks->swapped = true;
3882 out_unlock:
3883 	spin_unlock(&blocks->lock);
3884 out:
3885 	if (ret < 0)
3886 		fs_info->qgroup_flags |=
3887 			BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3888 	return ret;
3889 }
3890 
3891 /*
3892  * Check if the tree block is a subtree root, and if so do the needed
3893  * delayed subtree trace for qgroup.
3894  *
3895  * This is called during btrfs_cow_block().
3896  */
3897 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
3898 					 struct btrfs_root *root,
3899 					 struct extent_buffer *subvol_eb)
3900 {
3901 	struct btrfs_fs_info *fs_info = root->fs_info;
3902 	struct btrfs_qgroup_swapped_blocks *blocks = &root->swapped_blocks;
3903 	struct btrfs_qgroup_swapped_block *block;
3904 	struct extent_buffer *reloc_eb = NULL;
3905 	struct rb_node *node;
3906 	bool found = false;
3907 	bool swapped = false;
3908 	int level = btrfs_header_level(subvol_eb);
3909 	int ret = 0;
3910 	int i;
3911 
3912 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
3913 		return 0;
3914 	if (!is_fstree(root->root_key.objectid) || !root->reloc_root)
3915 		return 0;
3916 
3917 	spin_lock(&blocks->lock);
3918 	if (!blocks->swapped) {
3919 		spin_unlock(&blocks->lock);
3920 		return 0;
3921 	}
3922 	node = blocks->blocks[level].rb_node;
3923 
3924 	while (node) {
3925 		block = rb_entry(node, struct btrfs_qgroup_swapped_block, node);
3926 		if (block->subvol_bytenr < subvol_eb->start) {
3927 			node = node->rb_left;
3928 		} else if (block->subvol_bytenr > subvol_eb->start) {
3929 			node = node->rb_right;
3930 		} else {
3931 			found = true;
3932 			break;
3933 		}
3934 	}
3935 	if (!found) {
3936 		spin_unlock(&blocks->lock);
3937 		goto out;
3938 	}
3939 	/* Found one, remove it from @blocks first and update blocks->swapped */
3940 	rb_erase(&block->node, &blocks->blocks[level]);
3941 	for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3942 		if (RB_EMPTY_ROOT(&blocks->blocks[i])) {
3943 			swapped = true;
3944 			break;
3945 		}
3946 	}
3947 	blocks->swapped = swapped;
3948 	spin_unlock(&blocks->lock);
3949 
3950 	/* Read out reloc subtree root */
3951 	reloc_eb = read_tree_block(fs_info, block->reloc_bytenr,
3952 				   block->reloc_generation, block->level,
3953 				   &block->first_key);
3954 	if (IS_ERR(reloc_eb)) {
3955 		ret = PTR_ERR(reloc_eb);
3956 		reloc_eb = NULL;
3957 		goto free_out;
3958 	}
3959 	if (!extent_buffer_uptodate(reloc_eb)) {
3960 		ret = -EIO;
3961 		goto free_out;
3962 	}
3963 
3964 	ret = qgroup_trace_subtree_swap(trans, reloc_eb, subvol_eb,
3965 			block->last_snapshot, block->trace_leaf);
3966 free_out:
3967 	kfree(block);
3968 	free_extent_buffer(reloc_eb);
3969 out:
3970 	if (ret < 0) {
3971 		btrfs_err_rl(fs_info,
3972 			     "failed to account subtree at bytenr %llu: %d",
3973 			     subvol_eb->start, ret);
3974 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3975 	}
3976 	return ret;
3977 }
3978