xref: /openbmc/linux/fs/btrfs/qgroup.c (revision 068b88cc)
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 fuer 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 umounting
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 	/*
898 	 * 1 for quota root item
899 	 * 1 for BTRFS_QGROUP_STATUS item
900 	 *
901 	 * Yet we also need 2*n items for a QGROUP_INFO/QGROUP_LIMIT items
902 	 * per subvolume. However those are not currently reserved since it
903 	 * would be a lot of overkill.
904 	 */
905 	trans = btrfs_start_transaction(tree_root, 2);
906 	if (IS_ERR(trans)) {
907 		ret = PTR_ERR(trans);
908 		trans = NULL;
909 		goto out;
910 	}
911 
912 	fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
913 	if (!fs_info->qgroup_ulist) {
914 		ret = -ENOMEM;
915 		btrfs_abort_transaction(trans, ret);
916 		goto out;
917 	}
918 
919 	/*
920 	 * initially create the quota tree
921 	 */
922 	quota_root = btrfs_create_tree(trans, fs_info,
923 				       BTRFS_QUOTA_TREE_OBJECTID);
924 	if (IS_ERR(quota_root)) {
925 		ret =  PTR_ERR(quota_root);
926 		btrfs_abort_transaction(trans, ret);
927 		goto out;
928 	}
929 
930 	path = btrfs_alloc_path();
931 	if (!path) {
932 		ret = -ENOMEM;
933 		btrfs_abort_transaction(trans, ret);
934 		goto out_free_root;
935 	}
936 
937 	key.objectid = 0;
938 	key.type = BTRFS_QGROUP_STATUS_KEY;
939 	key.offset = 0;
940 
941 	ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
942 				      sizeof(*ptr));
943 	if (ret) {
944 		btrfs_abort_transaction(trans, ret);
945 		goto out_free_path;
946 	}
947 
948 	leaf = path->nodes[0];
949 	ptr = btrfs_item_ptr(leaf, path->slots[0],
950 				 struct btrfs_qgroup_status_item);
951 	btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
952 	btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
953 	fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON |
954 				BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
955 	btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags);
956 	btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
957 
958 	btrfs_mark_buffer_dirty(leaf);
959 
960 	key.objectid = 0;
961 	key.type = BTRFS_ROOT_REF_KEY;
962 	key.offset = 0;
963 
964 	btrfs_release_path(path);
965 	ret = btrfs_search_slot_for_read(tree_root, &key, path, 1, 0);
966 	if (ret > 0)
967 		goto out_add_root;
968 	if (ret < 0) {
969 		btrfs_abort_transaction(trans, ret);
970 		goto out_free_path;
971 	}
972 
973 	while (1) {
974 		slot = path->slots[0];
975 		leaf = path->nodes[0];
976 		btrfs_item_key_to_cpu(leaf, &found_key, slot);
977 
978 		if (found_key.type == BTRFS_ROOT_REF_KEY) {
979 			ret = add_qgroup_item(trans, quota_root,
980 					      found_key.offset);
981 			if (ret) {
982 				btrfs_abort_transaction(trans, ret);
983 				goto out_free_path;
984 			}
985 
986 			qgroup = add_qgroup_rb(fs_info, found_key.offset);
987 			if (IS_ERR(qgroup)) {
988 				ret = PTR_ERR(qgroup);
989 				btrfs_abort_transaction(trans, ret);
990 				goto out_free_path;
991 			}
992 		}
993 		ret = btrfs_next_item(tree_root, path);
994 		if (ret < 0) {
995 			btrfs_abort_transaction(trans, ret);
996 			goto out_free_path;
997 		}
998 		if (ret)
999 			break;
1000 	}
1001 
1002 out_add_root:
1003 	btrfs_release_path(path);
1004 	ret = add_qgroup_item(trans, quota_root, BTRFS_FS_TREE_OBJECTID);
1005 	if (ret) {
1006 		btrfs_abort_transaction(trans, ret);
1007 		goto out_free_path;
1008 	}
1009 
1010 	qgroup = add_qgroup_rb(fs_info, BTRFS_FS_TREE_OBJECTID);
1011 	if (IS_ERR(qgroup)) {
1012 		ret = PTR_ERR(qgroup);
1013 		btrfs_abort_transaction(trans, ret);
1014 		goto out_free_path;
1015 	}
1016 	spin_lock(&fs_info->qgroup_lock);
1017 	fs_info->quota_root = quota_root;
1018 	set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1019 	spin_unlock(&fs_info->qgroup_lock);
1020 
1021 	ret = btrfs_commit_transaction(trans);
1022 	trans = NULL;
1023 	if (ret)
1024 		goto out_free_path;
1025 
1026 	ret = qgroup_rescan_init(fs_info, 0, 1);
1027 	if (!ret) {
1028 	        qgroup_rescan_zero_tracking(fs_info);
1029 	        btrfs_queue_work(fs_info->qgroup_rescan_workers,
1030 	                         &fs_info->qgroup_rescan_work);
1031 	}
1032 
1033 out_free_path:
1034 	btrfs_free_path(path);
1035 out_free_root:
1036 	if (ret) {
1037 		free_extent_buffer(quota_root->node);
1038 		free_extent_buffer(quota_root->commit_root);
1039 		kfree(quota_root);
1040 	}
1041 out:
1042 	if (ret) {
1043 		ulist_free(fs_info->qgroup_ulist);
1044 		fs_info->qgroup_ulist = NULL;
1045 		if (trans)
1046 			btrfs_end_transaction(trans);
1047 	}
1048 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1049 	return ret;
1050 }
1051 
1052 int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
1053 {
1054 	struct btrfs_root *quota_root;
1055 	struct btrfs_trans_handle *trans = NULL;
1056 	int ret = 0;
1057 
1058 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1059 	if (!fs_info->quota_root)
1060 		goto out;
1061 
1062 	/*
1063 	 * 1 For the root item
1064 	 *
1065 	 * We should also reserve enough items for the quota tree deletion in
1066 	 * btrfs_clean_quota_tree but this is not done.
1067 	 */
1068 	trans = btrfs_start_transaction(fs_info->tree_root, 1);
1069 	if (IS_ERR(trans)) {
1070 		ret = PTR_ERR(trans);
1071 		goto out;
1072 	}
1073 
1074 	clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1075 	btrfs_qgroup_wait_for_completion(fs_info, false);
1076 	spin_lock(&fs_info->qgroup_lock);
1077 	quota_root = fs_info->quota_root;
1078 	fs_info->quota_root = NULL;
1079 	fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
1080 	spin_unlock(&fs_info->qgroup_lock);
1081 
1082 	btrfs_free_qgroup_config(fs_info);
1083 
1084 	ret = btrfs_clean_quota_tree(trans, quota_root);
1085 	if (ret) {
1086 		btrfs_abort_transaction(trans, ret);
1087 		goto end_trans;
1088 	}
1089 
1090 	ret = btrfs_del_root(trans, &quota_root->root_key);
1091 	if (ret) {
1092 		btrfs_abort_transaction(trans, ret);
1093 		goto end_trans;
1094 	}
1095 
1096 	list_del(&quota_root->dirty_list);
1097 
1098 	btrfs_tree_lock(quota_root->node);
1099 	clean_tree_block(fs_info, quota_root->node);
1100 	btrfs_tree_unlock(quota_root->node);
1101 	btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1);
1102 
1103 	free_extent_buffer(quota_root->node);
1104 	free_extent_buffer(quota_root->commit_root);
1105 	kfree(quota_root);
1106 
1107 end_trans:
1108 	ret = btrfs_end_transaction(trans);
1109 out:
1110 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1111 	return ret;
1112 }
1113 
1114 static void qgroup_dirty(struct btrfs_fs_info *fs_info,
1115 			 struct btrfs_qgroup *qgroup)
1116 {
1117 	if (list_empty(&qgroup->dirty))
1118 		list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
1119 }
1120 
1121 /*
1122  * The easy accounting, we're updating qgroup relationship whose child qgroup
1123  * only has exclusive extents.
1124  *
1125  * In this case, all exclsuive extents will also be exlusive for parent, so
1126  * excl/rfer just get added/removed.
1127  *
1128  * So is qgroup reservation space, which should also be added/removed to
1129  * parent.
1130  * Or when child tries to release reservation space, parent will underflow its
1131  * reservation (for relationship adding case).
1132  *
1133  * Caller should hold fs_info->qgroup_lock.
1134  */
1135 static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
1136 				    struct ulist *tmp, u64 ref_root,
1137 				    struct btrfs_qgroup *src, int sign)
1138 {
1139 	struct btrfs_qgroup *qgroup;
1140 	struct btrfs_qgroup_list *glist;
1141 	struct ulist_node *unode;
1142 	struct ulist_iterator uiter;
1143 	u64 num_bytes = src->excl;
1144 	int ret = 0;
1145 
1146 	qgroup = find_qgroup_rb(fs_info, ref_root);
1147 	if (!qgroup)
1148 		goto out;
1149 
1150 	qgroup->rfer += sign * num_bytes;
1151 	qgroup->rfer_cmpr += sign * num_bytes;
1152 
1153 	WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1154 	qgroup->excl += sign * num_bytes;
1155 	qgroup->excl_cmpr += sign * num_bytes;
1156 
1157 	if (sign > 0)
1158 		qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1159 	else
1160 		qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1161 
1162 	qgroup_dirty(fs_info, qgroup);
1163 
1164 	/* Get all of the parent groups that contain this qgroup */
1165 	list_for_each_entry(glist, &qgroup->groups, next_group) {
1166 		ret = ulist_add(tmp, glist->group->qgroupid,
1167 				qgroup_to_aux(glist->group), GFP_ATOMIC);
1168 		if (ret < 0)
1169 			goto out;
1170 	}
1171 
1172 	/* Iterate all of the parents and adjust their reference counts */
1173 	ULIST_ITER_INIT(&uiter);
1174 	while ((unode = ulist_next(tmp, &uiter))) {
1175 		qgroup = unode_aux_to_qgroup(unode);
1176 		qgroup->rfer += sign * num_bytes;
1177 		qgroup->rfer_cmpr += sign * num_bytes;
1178 		WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1179 		qgroup->excl += sign * num_bytes;
1180 		if (sign > 0)
1181 			qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1182 		else
1183 			qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1184 		qgroup->excl_cmpr += sign * num_bytes;
1185 		qgroup_dirty(fs_info, qgroup);
1186 
1187 		/* Add any parents of the parents */
1188 		list_for_each_entry(glist, &qgroup->groups, next_group) {
1189 			ret = ulist_add(tmp, glist->group->qgroupid,
1190 					qgroup_to_aux(glist->group), GFP_ATOMIC);
1191 			if (ret < 0)
1192 				goto out;
1193 		}
1194 	}
1195 	ret = 0;
1196 out:
1197 	return ret;
1198 }
1199 
1200 
1201 /*
1202  * Quick path for updating qgroup with only excl refs.
1203  *
1204  * In that case, just update all parent will be enough.
1205  * Or we needs to do a full rescan.
1206  * Caller should also hold fs_info->qgroup_lock.
1207  *
1208  * Return 0 for quick update, return >0 for need to full rescan
1209  * and mark INCONSISTENT flag.
1210  * Return < 0 for other error.
1211  */
1212 static int quick_update_accounting(struct btrfs_fs_info *fs_info,
1213 				   struct ulist *tmp, u64 src, u64 dst,
1214 				   int sign)
1215 {
1216 	struct btrfs_qgroup *qgroup;
1217 	int ret = 1;
1218 	int err = 0;
1219 
1220 	qgroup = find_qgroup_rb(fs_info, src);
1221 	if (!qgroup)
1222 		goto out;
1223 	if (qgroup->excl == qgroup->rfer) {
1224 		ret = 0;
1225 		err = __qgroup_excl_accounting(fs_info, tmp, dst,
1226 					       qgroup, sign);
1227 		if (err < 0) {
1228 			ret = err;
1229 			goto out;
1230 		}
1231 	}
1232 out:
1233 	if (ret)
1234 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1235 	return ret;
1236 }
1237 
1238 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1239 			      u64 dst)
1240 {
1241 	struct btrfs_fs_info *fs_info = trans->fs_info;
1242 	struct btrfs_root *quota_root;
1243 	struct btrfs_qgroup *parent;
1244 	struct btrfs_qgroup *member;
1245 	struct btrfs_qgroup_list *list;
1246 	struct ulist *tmp;
1247 	int ret = 0;
1248 
1249 	/* Check the level of src and dst first */
1250 	if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
1251 		return -EINVAL;
1252 
1253 	tmp = ulist_alloc(GFP_KERNEL);
1254 	if (!tmp)
1255 		return -ENOMEM;
1256 
1257 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1258 	quota_root = fs_info->quota_root;
1259 	if (!quota_root) {
1260 		ret = -EINVAL;
1261 		goto out;
1262 	}
1263 	member = find_qgroup_rb(fs_info, src);
1264 	parent = find_qgroup_rb(fs_info, dst);
1265 	if (!member || !parent) {
1266 		ret = -EINVAL;
1267 		goto out;
1268 	}
1269 
1270 	/* check if such qgroup relation exist firstly */
1271 	list_for_each_entry(list, &member->groups, next_group) {
1272 		if (list->group == parent) {
1273 			ret = -EEXIST;
1274 			goto out;
1275 		}
1276 	}
1277 
1278 	ret = add_qgroup_relation_item(trans, src, dst);
1279 	if (ret)
1280 		goto out;
1281 
1282 	ret = add_qgroup_relation_item(trans, dst, src);
1283 	if (ret) {
1284 		del_qgroup_relation_item(trans, src, dst);
1285 		goto out;
1286 	}
1287 
1288 	spin_lock(&fs_info->qgroup_lock);
1289 	ret = add_relation_rb(fs_info, src, dst);
1290 	if (ret < 0) {
1291 		spin_unlock(&fs_info->qgroup_lock);
1292 		goto out;
1293 	}
1294 	ret = quick_update_accounting(fs_info, tmp, src, dst, 1);
1295 	spin_unlock(&fs_info->qgroup_lock);
1296 out:
1297 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1298 	ulist_free(tmp);
1299 	return ret;
1300 }
1301 
1302 static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1303 				 u64 dst)
1304 {
1305 	struct btrfs_fs_info *fs_info = trans->fs_info;
1306 	struct btrfs_root *quota_root;
1307 	struct btrfs_qgroup *parent;
1308 	struct btrfs_qgroup *member;
1309 	struct btrfs_qgroup_list *list;
1310 	struct ulist *tmp;
1311 	int ret = 0;
1312 	int err;
1313 
1314 	tmp = ulist_alloc(GFP_KERNEL);
1315 	if (!tmp)
1316 		return -ENOMEM;
1317 
1318 	quota_root = fs_info->quota_root;
1319 	if (!quota_root) {
1320 		ret = -EINVAL;
1321 		goto out;
1322 	}
1323 
1324 	member = find_qgroup_rb(fs_info, src);
1325 	parent = find_qgroup_rb(fs_info, dst);
1326 	if (!member || !parent) {
1327 		ret = -EINVAL;
1328 		goto out;
1329 	}
1330 
1331 	/* check if such qgroup relation exist firstly */
1332 	list_for_each_entry(list, &member->groups, next_group) {
1333 		if (list->group == parent)
1334 			goto exist;
1335 	}
1336 	ret = -ENOENT;
1337 	goto out;
1338 exist:
1339 	ret = del_qgroup_relation_item(trans, src, dst);
1340 	err = del_qgroup_relation_item(trans, dst, src);
1341 	if (err && !ret)
1342 		ret = err;
1343 
1344 	spin_lock(&fs_info->qgroup_lock);
1345 	del_relation_rb(fs_info, src, dst);
1346 	ret = quick_update_accounting(fs_info, tmp, src, dst, -1);
1347 	spin_unlock(&fs_info->qgroup_lock);
1348 out:
1349 	ulist_free(tmp);
1350 	return ret;
1351 }
1352 
1353 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1354 			      u64 dst)
1355 {
1356 	struct btrfs_fs_info *fs_info = trans->fs_info;
1357 	int ret = 0;
1358 
1359 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1360 	ret = __del_qgroup_relation(trans, src, dst);
1361 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1362 
1363 	return ret;
1364 }
1365 
1366 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1367 {
1368 	struct btrfs_fs_info *fs_info = trans->fs_info;
1369 	struct btrfs_root *quota_root;
1370 	struct btrfs_qgroup *qgroup;
1371 	int ret = 0;
1372 
1373 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1374 	quota_root = fs_info->quota_root;
1375 	if (!quota_root) {
1376 		ret = -EINVAL;
1377 		goto out;
1378 	}
1379 	qgroup = find_qgroup_rb(fs_info, qgroupid);
1380 	if (qgroup) {
1381 		ret = -EEXIST;
1382 		goto out;
1383 	}
1384 
1385 	ret = add_qgroup_item(trans, quota_root, qgroupid);
1386 	if (ret)
1387 		goto out;
1388 
1389 	spin_lock(&fs_info->qgroup_lock);
1390 	qgroup = add_qgroup_rb(fs_info, qgroupid);
1391 	spin_unlock(&fs_info->qgroup_lock);
1392 
1393 	if (IS_ERR(qgroup))
1394 		ret = PTR_ERR(qgroup);
1395 out:
1396 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1397 	return ret;
1398 }
1399 
1400 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1401 {
1402 	struct btrfs_fs_info *fs_info = trans->fs_info;
1403 	struct btrfs_root *quota_root;
1404 	struct btrfs_qgroup *qgroup;
1405 	struct btrfs_qgroup_list *list;
1406 	int ret = 0;
1407 
1408 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1409 	quota_root = fs_info->quota_root;
1410 	if (!quota_root) {
1411 		ret = -EINVAL;
1412 		goto out;
1413 	}
1414 
1415 	qgroup = find_qgroup_rb(fs_info, qgroupid);
1416 	if (!qgroup) {
1417 		ret = -ENOENT;
1418 		goto out;
1419 	} else {
1420 		/* check if there are no children of this qgroup */
1421 		if (!list_empty(&qgroup->members)) {
1422 			ret = -EBUSY;
1423 			goto out;
1424 		}
1425 	}
1426 	ret = del_qgroup_item(trans, qgroupid);
1427 	if (ret && ret != -ENOENT)
1428 		goto out;
1429 
1430 	while (!list_empty(&qgroup->groups)) {
1431 		list = list_first_entry(&qgroup->groups,
1432 					struct btrfs_qgroup_list, next_group);
1433 		ret = __del_qgroup_relation(trans, qgroupid,
1434 					    list->group->qgroupid);
1435 		if (ret)
1436 			goto out;
1437 	}
1438 
1439 	spin_lock(&fs_info->qgroup_lock);
1440 	del_qgroup_rb(fs_info, qgroupid);
1441 	spin_unlock(&fs_info->qgroup_lock);
1442 out:
1443 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1444 	return ret;
1445 }
1446 
1447 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
1448 		       struct btrfs_qgroup_limit *limit)
1449 {
1450 	struct btrfs_fs_info *fs_info = trans->fs_info;
1451 	struct btrfs_root *quota_root;
1452 	struct btrfs_qgroup *qgroup;
1453 	int ret = 0;
1454 	/* Sometimes we would want to clear the limit on this qgroup.
1455 	 * To meet this requirement, we treat the -1 as a special value
1456 	 * which tell kernel to clear the limit on this qgroup.
1457 	 */
1458 	const u64 CLEAR_VALUE = -1;
1459 
1460 	mutex_lock(&fs_info->qgroup_ioctl_lock);
1461 	quota_root = fs_info->quota_root;
1462 	if (!quota_root) {
1463 		ret = -EINVAL;
1464 		goto out;
1465 	}
1466 
1467 	qgroup = find_qgroup_rb(fs_info, qgroupid);
1468 	if (!qgroup) {
1469 		ret = -ENOENT;
1470 		goto out;
1471 	}
1472 
1473 	spin_lock(&fs_info->qgroup_lock);
1474 	if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_RFER) {
1475 		if (limit->max_rfer == CLEAR_VALUE) {
1476 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1477 			limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1478 			qgroup->max_rfer = 0;
1479 		} else {
1480 			qgroup->max_rfer = limit->max_rfer;
1481 		}
1482 	}
1483 	if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
1484 		if (limit->max_excl == CLEAR_VALUE) {
1485 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1486 			limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1487 			qgroup->max_excl = 0;
1488 		} else {
1489 			qgroup->max_excl = limit->max_excl;
1490 		}
1491 	}
1492 	if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_RFER) {
1493 		if (limit->rsv_rfer == CLEAR_VALUE) {
1494 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1495 			limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1496 			qgroup->rsv_rfer = 0;
1497 		} else {
1498 			qgroup->rsv_rfer = limit->rsv_rfer;
1499 		}
1500 	}
1501 	if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_EXCL) {
1502 		if (limit->rsv_excl == CLEAR_VALUE) {
1503 			qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1504 			limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1505 			qgroup->rsv_excl = 0;
1506 		} else {
1507 			qgroup->rsv_excl = limit->rsv_excl;
1508 		}
1509 	}
1510 	qgroup->lim_flags |= limit->flags;
1511 
1512 	spin_unlock(&fs_info->qgroup_lock);
1513 
1514 	ret = update_qgroup_limit_item(trans, qgroup);
1515 	if (ret) {
1516 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1517 		btrfs_info(fs_info, "unable to update quota limit for %llu",
1518 		       qgroupid);
1519 	}
1520 
1521 out:
1522 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
1523 	return ret;
1524 }
1525 
1526 int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
1527 				struct btrfs_delayed_ref_root *delayed_refs,
1528 				struct btrfs_qgroup_extent_record *record)
1529 {
1530 	struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
1531 	struct rb_node *parent_node = NULL;
1532 	struct btrfs_qgroup_extent_record *entry;
1533 	u64 bytenr = record->bytenr;
1534 
1535 	lockdep_assert_held(&delayed_refs->lock);
1536 	trace_btrfs_qgroup_trace_extent(fs_info, record);
1537 
1538 	while (*p) {
1539 		parent_node = *p;
1540 		entry = rb_entry(parent_node, struct btrfs_qgroup_extent_record,
1541 				 node);
1542 		if (bytenr < entry->bytenr)
1543 			p = &(*p)->rb_left;
1544 		else if (bytenr > entry->bytenr)
1545 			p = &(*p)->rb_right;
1546 		else
1547 			return 1;
1548 	}
1549 
1550 	rb_link_node(&record->node, parent_node, p);
1551 	rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
1552 	return 0;
1553 }
1554 
1555 int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
1556 				   struct btrfs_qgroup_extent_record *qrecord)
1557 {
1558 	struct ulist *old_root;
1559 	u64 bytenr = qrecord->bytenr;
1560 	int ret;
1561 
1562 	ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false);
1563 	if (ret < 0) {
1564 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1565 		btrfs_warn(fs_info,
1566 "error accounting new delayed refs extent (err code: %d), quota inconsistent",
1567 			ret);
1568 		return 0;
1569 	}
1570 
1571 	/*
1572 	 * Here we don't need to get the lock of
1573 	 * trans->transaction->delayed_refs, since inserted qrecord won't
1574 	 * be deleted, only qrecord->node may be modified (new qrecord insert)
1575 	 *
1576 	 * So modifying qrecord->old_roots is safe here
1577 	 */
1578 	qrecord->old_roots = old_root;
1579 	return 0;
1580 }
1581 
1582 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
1583 			      u64 num_bytes, gfp_t gfp_flag)
1584 {
1585 	struct btrfs_fs_info *fs_info = trans->fs_info;
1586 	struct btrfs_qgroup_extent_record *record;
1587 	struct btrfs_delayed_ref_root *delayed_refs;
1588 	int ret;
1589 
1590 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)
1591 	    || bytenr == 0 || num_bytes == 0)
1592 		return 0;
1593 	record = kmalloc(sizeof(*record), gfp_flag);
1594 	if (!record)
1595 		return -ENOMEM;
1596 
1597 	delayed_refs = &trans->transaction->delayed_refs;
1598 	record->bytenr = bytenr;
1599 	record->num_bytes = num_bytes;
1600 	record->old_roots = NULL;
1601 
1602 	spin_lock(&delayed_refs->lock);
1603 	ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record);
1604 	spin_unlock(&delayed_refs->lock);
1605 	if (ret > 0) {
1606 		kfree(record);
1607 		return 0;
1608 	}
1609 	return btrfs_qgroup_trace_extent_post(fs_info, record);
1610 }
1611 
1612 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
1613 				  struct extent_buffer *eb)
1614 {
1615 	struct btrfs_fs_info *fs_info = trans->fs_info;
1616 	int nr = btrfs_header_nritems(eb);
1617 	int i, extent_type, ret;
1618 	struct btrfs_key key;
1619 	struct btrfs_file_extent_item *fi;
1620 	u64 bytenr, num_bytes;
1621 
1622 	/* We can be called directly from walk_up_proc() */
1623 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1624 		return 0;
1625 
1626 	for (i = 0; i < nr; i++) {
1627 		btrfs_item_key_to_cpu(eb, &key, i);
1628 
1629 		if (key.type != BTRFS_EXTENT_DATA_KEY)
1630 			continue;
1631 
1632 		fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
1633 		/* filter out non qgroup-accountable extents  */
1634 		extent_type = btrfs_file_extent_type(eb, fi);
1635 
1636 		if (extent_type == BTRFS_FILE_EXTENT_INLINE)
1637 			continue;
1638 
1639 		bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
1640 		if (!bytenr)
1641 			continue;
1642 
1643 		num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
1644 
1645 		ret = btrfs_qgroup_trace_extent(trans, bytenr, num_bytes,
1646 						GFP_NOFS);
1647 		if (ret)
1648 			return ret;
1649 	}
1650 	cond_resched();
1651 	return 0;
1652 }
1653 
1654 /*
1655  * Walk up the tree from the bottom, freeing leaves and any interior
1656  * nodes which have had all slots visited. If a node (leaf or
1657  * interior) is freed, the node above it will have it's slot
1658  * incremented. The root node will never be freed.
1659  *
1660  * At the end of this function, we should have a path which has all
1661  * slots incremented to the next position for a search. If we need to
1662  * read a new node it will be NULL and the node above it will have the
1663  * correct slot selected for a later read.
1664  *
1665  * If we increment the root nodes slot counter past the number of
1666  * elements, 1 is returned to signal completion of the search.
1667  */
1668 static int adjust_slots_upwards(struct btrfs_path *path, int root_level)
1669 {
1670 	int level = 0;
1671 	int nr, slot;
1672 	struct extent_buffer *eb;
1673 
1674 	if (root_level == 0)
1675 		return 1;
1676 
1677 	while (level <= root_level) {
1678 		eb = path->nodes[level];
1679 		nr = btrfs_header_nritems(eb);
1680 		path->slots[level]++;
1681 		slot = path->slots[level];
1682 		if (slot >= nr || level == 0) {
1683 			/*
1684 			 * Don't free the root -  we will detect this
1685 			 * condition after our loop and return a
1686 			 * positive value for caller to stop walking the tree.
1687 			 */
1688 			if (level != root_level) {
1689 				btrfs_tree_unlock_rw(eb, path->locks[level]);
1690 				path->locks[level] = 0;
1691 
1692 				free_extent_buffer(eb);
1693 				path->nodes[level] = NULL;
1694 				path->slots[level] = 0;
1695 			}
1696 		} else {
1697 			/*
1698 			 * We have a valid slot to walk back down
1699 			 * from. Stop here so caller can process these
1700 			 * new nodes.
1701 			 */
1702 			break;
1703 		}
1704 
1705 		level++;
1706 	}
1707 
1708 	eb = path->nodes[root_level];
1709 	if (path->slots[root_level] >= btrfs_header_nritems(eb))
1710 		return 1;
1711 
1712 	return 0;
1713 }
1714 
1715 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
1716 			       struct extent_buffer *root_eb,
1717 			       u64 root_gen, int root_level)
1718 {
1719 	struct btrfs_fs_info *fs_info = trans->fs_info;
1720 	int ret = 0;
1721 	int level;
1722 	struct extent_buffer *eb = root_eb;
1723 	struct btrfs_path *path = NULL;
1724 
1725 	BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
1726 	BUG_ON(root_eb == NULL);
1727 
1728 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1729 		return 0;
1730 
1731 	if (!extent_buffer_uptodate(root_eb)) {
1732 		ret = btrfs_read_buffer(root_eb, root_gen, root_level, NULL);
1733 		if (ret)
1734 			goto out;
1735 	}
1736 
1737 	if (root_level == 0) {
1738 		ret = btrfs_qgroup_trace_leaf_items(trans, root_eb);
1739 		goto out;
1740 	}
1741 
1742 	path = btrfs_alloc_path();
1743 	if (!path)
1744 		return -ENOMEM;
1745 
1746 	/*
1747 	 * Walk down the tree.  Missing extent blocks are filled in as
1748 	 * we go. Metadata is accounted every time we read a new
1749 	 * extent block.
1750 	 *
1751 	 * When we reach a leaf, we account for file extent items in it,
1752 	 * walk back up the tree (adjusting slot pointers as we go)
1753 	 * and restart the search process.
1754 	 */
1755 	extent_buffer_get(root_eb); /* For path */
1756 	path->nodes[root_level] = root_eb;
1757 	path->slots[root_level] = 0;
1758 	path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
1759 walk_down:
1760 	level = root_level;
1761 	while (level >= 0) {
1762 		if (path->nodes[level] == NULL) {
1763 			struct btrfs_key first_key;
1764 			int parent_slot;
1765 			u64 child_gen;
1766 			u64 child_bytenr;
1767 
1768 			/*
1769 			 * We need to get child blockptr/gen from parent before
1770 			 * we can read it.
1771 			  */
1772 			eb = path->nodes[level + 1];
1773 			parent_slot = path->slots[level + 1];
1774 			child_bytenr = btrfs_node_blockptr(eb, parent_slot);
1775 			child_gen = btrfs_node_ptr_generation(eb, parent_slot);
1776 			btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
1777 
1778 			eb = read_tree_block(fs_info, child_bytenr, child_gen,
1779 					     level, &first_key);
1780 			if (IS_ERR(eb)) {
1781 				ret = PTR_ERR(eb);
1782 				goto out;
1783 			} else if (!extent_buffer_uptodate(eb)) {
1784 				free_extent_buffer(eb);
1785 				ret = -EIO;
1786 				goto out;
1787 			}
1788 
1789 			path->nodes[level] = eb;
1790 			path->slots[level] = 0;
1791 
1792 			btrfs_tree_read_lock(eb);
1793 			btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1794 			path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
1795 
1796 			ret = btrfs_qgroup_trace_extent(trans, child_bytenr,
1797 							fs_info->nodesize,
1798 							GFP_NOFS);
1799 			if (ret)
1800 				goto out;
1801 		}
1802 
1803 		if (level == 0) {
1804 			ret = btrfs_qgroup_trace_leaf_items(trans,
1805 							    path->nodes[level]);
1806 			if (ret)
1807 				goto out;
1808 
1809 			/* Nonzero return here means we completed our search */
1810 			ret = adjust_slots_upwards(path, root_level);
1811 			if (ret)
1812 				break;
1813 
1814 			/* Restart search with new slots */
1815 			goto walk_down;
1816 		}
1817 
1818 		level--;
1819 	}
1820 
1821 	ret = 0;
1822 out:
1823 	btrfs_free_path(path);
1824 
1825 	return ret;
1826 }
1827 
1828 #define UPDATE_NEW	0
1829 #define UPDATE_OLD	1
1830 /*
1831  * Walk all of the roots that points to the bytenr and adjust their refcnts.
1832  */
1833 static int qgroup_update_refcnt(struct btrfs_fs_info *fs_info,
1834 				struct ulist *roots, struct ulist *tmp,
1835 				struct ulist *qgroups, u64 seq, int update_old)
1836 {
1837 	struct ulist_node *unode;
1838 	struct ulist_iterator uiter;
1839 	struct ulist_node *tmp_unode;
1840 	struct ulist_iterator tmp_uiter;
1841 	struct btrfs_qgroup *qg;
1842 	int ret = 0;
1843 
1844 	if (!roots)
1845 		return 0;
1846 	ULIST_ITER_INIT(&uiter);
1847 	while ((unode = ulist_next(roots, &uiter))) {
1848 		qg = find_qgroup_rb(fs_info, unode->val);
1849 		if (!qg)
1850 			continue;
1851 
1852 		ulist_reinit(tmp);
1853 		ret = ulist_add(qgroups, qg->qgroupid, qgroup_to_aux(qg),
1854 				GFP_ATOMIC);
1855 		if (ret < 0)
1856 			return ret;
1857 		ret = ulist_add(tmp, qg->qgroupid, qgroup_to_aux(qg), GFP_ATOMIC);
1858 		if (ret < 0)
1859 			return ret;
1860 		ULIST_ITER_INIT(&tmp_uiter);
1861 		while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
1862 			struct btrfs_qgroup_list *glist;
1863 
1864 			qg = unode_aux_to_qgroup(tmp_unode);
1865 			if (update_old)
1866 				btrfs_qgroup_update_old_refcnt(qg, seq, 1);
1867 			else
1868 				btrfs_qgroup_update_new_refcnt(qg, seq, 1);
1869 			list_for_each_entry(glist, &qg->groups, next_group) {
1870 				ret = ulist_add(qgroups, glist->group->qgroupid,
1871 						qgroup_to_aux(glist->group),
1872 						GFP_ATOMIC);
1873 				if (ret < 0)
1874 					return ret;
1875 				ret = ulist_add(tmp, glist->group->qgroupid,
1876 						qgroup_to_aux(glist->group),
1877 						GFP_ATOMIC);
1878 				if (ret < 0)
1879 					return ret;
1880 			}
1881 		}
1882 	}
1883 	return 0;
1884 }
1885 
1886 /*
1887  * Update qgroup rfer/excl counters.
1888  * Rfer update is easy, codes can explain themselves.
1889  *
1890  * Excl update is tricky, the update is split into 2 part.
1891  * Part 1: Possible exclusive <-> sharing detect:
1892  *	|	A	|	!A	|
1893  *  -------------------------------------
1894  *  B	|	*	|	-	|
1895  *  -------------------------------------
1896  *  !B	|	+	|	**	|
1897  *  -------------------------------------
1898  *
1899  * Conditions:
1900  * A:	cur_old_roots < nr_old_roots	(not exclusive before)
1901  * !A:	cur_old_roots == nr_old_roots	(possible exclusive before)
1902  * B:	cur_new_roots < nr_new_roots	(not exclusive now)
1903  * !B:	cur_new_roots == nr_new_roots	(possible exclusive now)
1904  *
1905  * Results:
1906  * +: Possible sharing -> exclusive	-: Possible exclusive -> sharing
1907  * *: Definitely not changed.		**: Possible unchanged.
1908  *
1909  * For !A and !B condition, the exception is cur_old/new_roots == 0 case.
1910  *
1911  * To make the logic clear, we first use condition A and B to split
1912  * combination into 4 results.
1913  *
1914  * Then, for result "+" and "-", check old/new_roots == 0 case, as in them
1915  * only on variant maybe 0.
1916  *
1917  * Lastly, check result **, since there are 2 variants maybe 0, split them
1918  * again(2x2).
1919  * But this time we don't need to consider other things, the codes and logic
1920  * is easy to understand now.
1921  */
1922 static int qgroup_update_counters(struct btrfs_fs_info *fs_info,
1923 				  struct ulist *qgroups,
1924 				  u64 nr_old_roots,
1925 				  u64 nr_new_roots,
1926 				  u64 num_bytes, u64 seq)
1927 {
1928 	struct ulist_node *unode;
1929 	struct ulist_iterator uiter;
1930 	struct btrfs_qgroup *qg;
1931 	u64 cur_new_count, cur_old_count;
1932 
1933 	ULIST_ITER_INIT(&uiter);
1934 	while ((unode = ulist_next(qgroups, &uiter))) {
1935 		bool dirty = false;
1936 
1937 		qg = unode_aux_to_qgroup(unode);
1938 		cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
1939 		cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
1940 
1941 		trace_qgroup_update_counters(fs_info, qg, cur_old_count,
1942 					     cur_new_count);
1943 
1944 		/* Rfer update part */
1945 		if (cur_old_count == 0 && cur_new_count > 0) {
1946 			qg->rfer += num_bytes;
1947 			qg->rfer_cmpr += num_bytes;
1948 			dirty = true;
1949 		}
1950 		if (cur_old_count > 0 && cur_new_count == 0) {
1951 			qg->rfer -= num_bytes;
1952 			qg->rfer_cmpr -= num_bytes;
1953 			dirty = true;
1954 		}
1955 
1956 		/* Excl update part */
1957 		/* Exclusive/none -> shared case */
1958 		if (cur_old_count == nr_old_roots &&
1959 		    cur_new_count < nr_new_roots) {
1960 			/* Exclusive -> shared */
1961 			if (cur_old_count != 0) {
1962 				qg->excl -= num_bytes;
1963 				qg->excl_cmpr -= num_bytes;
1964 				dirty = true;
1965 			}
1966 		}
1967 
1968 		/* Shared -> exclusive/none case */
1969 		if (cur_old_count < nr_old_roots &&
1970 		    cur_new_count == nr_new_roots) {
1971 			/* Shared->exclusive */
1972 			if (cur_new_count != 0) {
1973 				qg->excl += num_bytes;
1974 				qg->excl_cmpr += num_bytes;
1975 				dirty = true;
1976 			}
1977 		}
1978 
1979 		/* Exclusive/none -> exclusive/none case */
1980 		if (cur_old_count == nr_old_roots &&
1981 		    cur_new_count == nr_new_roots) {
1982 			if (cur_old_count == 0) {
1983 				/* None -> exclusive/none */
1984 
1985 				if (cur_new_count != 0) {
1986 					/* None -> exclusive */
1987 					qg->excl += num_bytes;
1988 					qg->excl_cmpr += num_bytes;
1989 					dirty = true;
1990 				}
1991 				/* None -> none, nothing changed */
1992 			} else {
1993 				/* Exclusive -> exclusive/none */
1994 
1995 				if (cur_new_count == 0) {
1996 					/* Exclusive -> none */
1997 					qg->excl -= num_bytes;
1998 					qg->excl_cmpr -= num_bytes;
1999 					dirty = true;
2000 				}
2001 				/* Exclusive -> exclusive, nothing changed */
2002 			}
2003 		}
2004 
2005 		if (dirty)
2006 			qgroup_dirty(fs_info, qg);
2007 	}
2008 	return 0;
2009 }
2010 
2011 /*
2012  * Check if the @roots potentially is a list of fs tree roots
2013  *
2014  * Return 0 for definitely not a fs/subvol tree roots ulist
2015  * Return 1 for possible fs/subvol tree roots in the list (considering an empty
2016  *          one as well)
2017  */
2018 static int maybe_fs_roots(struct ulist *roots)
2019 {
2020 	struct ulist_node *unode;
2021 	struct ulist_iterator uiter;
2022 
2023 	/* Empty one, still possible for fs roots */
2024 	if (!roots || roots->nnodes == 0)
2025 		return 1;
2026 
2027 	ULIST_ITER_INIT(&uiter);
2028 	unode = ulist_next(roots, &uiter);
2029 	if (!unode)
2030 		return 1;
2031 
2032 	/*
2033 	 * If it contains fs tree roots, then it must belong to fs/subvol
2034 	 * trees.
2035 	 * If it contains a non-fs tree, it won't be shared with fs/subvol trees.
2036 	 */
2037 	return is_fstree(unode->val);
2038 }
2039 
2040 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
2041 				u64 num_bytes, struct ulist *old_roots,
2042 				struct ulist *new_roots)
2043 {
2044 	struct btrfs_fs_info *fs_info = trans->fs_info;
2045 	struct ulist *qgroups = NULL;
2046 	struct ulist *tmp = NULL;
2047 	u64 seq;
2048 	u64 nr_new_roots = 0;
2049 	u64 nr_old_roots = 0;
2050 	int ret = 0;
2051 
2052 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2053 		return 0;
2054 
2055 	if (new_roots) {
2056 		if (!maybe_fs_roots(new_roots))
2057 			goto out_free;
2058 		nr_new_roots = new_roots->nnodes;
2059 	}
2060 	if (old_roots) {
2061 		if (!maybe_fs_roots(old_roots))
2062 			goto out_free;
2063 		nr_old_roots = old_roots->nnodes;
2064 	}
2065 
2066 	/* Quick exit, either not fs tree roots, or won't affect any qgroup */
2067 	if (nr_old_roots == 0 && nr_new_roots == 0)
2068 		goto out_free;
2069 
2070 	BUG_ON(!fs_info->quota_root);
2071 
2072 	trace_btrfs_qgroup_account_extent(fs_info, trans->transid, bytenr,
2073 					num_bytes, nr_old_roots, nr_new_roots);
2074 
2075 	qgroups = ulist_alloc(GFP_NOFS);
2076 	if (!qgroups) {
2077 		ret = -ENOMEM;
2078 		goto out_free;
2079 	}
2080 	tmp = ulist_alloc(GFP_NOFS);
2081 	if (!tmp) {
2082 		ret = -ENOMEM;
2083 		goto out_free;
2084 	}
2085 
2086 	mutex_lock(&fs_info->qgroup_rescan_lock);
2087 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
2088 		if (fs_info->qgroup_rescan_progress.objectid <= bytenr) {
2089 			mutex_unlock(&fs_info->qgroup_rescan_lock);
2090 			ret = 0;
2091 			goto out_free;
2092 		}
2093 	}
2094 	mutex_unlock(&fs_info->qgroup_rescan_lock);
2095 
2096 	spin_lock(&fs_info->qgroup_lock);
2097 	seq = fs_info->qgroup_seq;
2098 
2099 	/* Update old refcnts using old_roots */
2100 	ret = qgroup_update_refcnt(fs_info, old_roots, tmp, qgroups, seq,
2101 				   UPDATE_OLD);
2102 	if (ret < 0)
2103 		goto out;
2104 
2105 	/* Update new refcnts using new_roots */
2106 	ret = qgroup_update_refcnt(fs_info, new_roots, tmp, qgroups, seq,
2107 				   UPDATE_NEW);
2108 	if (ret < 0)
2109 		goto out;
2110 
2111 	qgroup_update_counters(fs_info, qgroups, nr_old_roots, nr_new_roots,
2112 			       num_bytes, seq);
2113 
2114 	/*
2115 	 * Bump qgroup_seq to avoid seq overlap
2116 	 */
2117 	fs_info->qgroup_seq += max(nr_old_roots, nr_new_roots) + 1;
2118 out:
2119 	spin_unlock(&fs_info->qgroup_lock);
2120 out_free:
2121 	ulist_free(tmp);
2122 	ulist_free(qgroups);
2123 	ulist_free(old_roots);
2124 	ulist_free(new_roots);
2125 	return ret;
2126 }
2127 
2128 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
2129 {
2130 	struct btrfs_fs_info *fs_info = trans->fs_info;
2131 	struct btrfs_qgroup_extent_record *record;
2132 	struct btrfs_delayed_ref_root *delayed_refs;
2133 	struct ulist *new_roots = NULL;
2134 	struct rb_node *node;
2135 	u64 qgroup_to_skip;
2136 	int ret = 0;
2137 
2138 	delayed_refs = &trans->transaction->delayed_refs;
2139 	qgroup_to_skip = delayed_refs->qgroup_to_skip;
2140 	while ((node = rb_first(&delayed_refs->dirty_extent_root))) {
2141 		record = rb_entry(node, struct btrfs_qgroup_extent_record,
2142 				  node);
2143 
2144 		trace_btrfs_qgroup_account_extents(fs_info, record);
2145 
2146 		if (!ret) {
2147 			/*
2148 			 * Old roots should be searched when inserting qgroup
2149 			 * extent record
2150 			 */
2151 			if (WARN_ON(!record->old_roots)) {
2152 				/* Search commit root to find old_roots */
2153 				ret = btrfs_find_all_roots(NULL, fs_info,
2154 						record->bytenr, 0,
2155 						&record->old_roots, false);
2156 				if (ret < 0)
2157 					goto cleanup;
2158 			}
2159 
2160 			/*
2161 			 * Use SEQ_LAST as time_seq to do special search, which
2162 			 * doesn't lock tree or delayed_refs and search current
2163 			 * root. It's safe inside commit_transaction().
2164 			 */
2165 			ret = btrfs_find_all_roots(trans, fs_info,
2166 				record->bytenr, SEQ_LAST, &new_roots, false);
2167 			if (ret < 0)
2168 				goto cleanup;
2169 			if (qgroup_to_skip) {
2170 				ulist_del(new_roots, qgroup_to_skip, 0);
2171 				ulist_del(record->old_roots, qgroup_to_skip,
2172 					  0);
2173 			}
2174 			ret = btrfs_qgroup_account_extent(trans, record->bytenr,
2175 							  record->num_bytes,
2176 							  record->old_roots,
2177 							  new_roots);
2178 			record->old_roots = NULL;
2179 			new_roots = NULL;
2180 		}
2181 cleanup:
2182 		ulist_free(record->old_roots);
2183 		ulist_free(new_roots);
2184 		new_roots = NULL;
2185 		rb_erase(node, &delayed_refs->dirty_extent_root);
2186 		kfree(record);
2187 
2188 	}
2189 	return ret;
2190 }
2191 
2192 /*
2193  * called from commit_transaction. Writes all changed qgroups to disk.
2194  */
2195 int btrfs_run_qgroups(struct btrfs_trans_handle *trans)
2196 {
2197 	struct btrfs_fs_info *fs_info = trans->fs_info;
2198 	struct btrfs_root *quota_root = fs_info->quota_root;
2199 	int ret = 0;
2200 
2201 	if (!quota_root)
2202 		return ret;
2203 
2204 	spin_lock(&fs_info->qgroup_lock);
2205 	while (!list_empty(&fs_info->dirty_qgroups)) {
2206 		struct btrfs_qgroup *qgroup;
2207 		qgroup = list_first_entry(&fs_info->dirty_qgroups,
2208 					  struct btrfs_qgroup, dirty);
2209 		list_del_init(&qgroup->dirty);
2210 		spin_unlock(&fs_info->qgroup_lock);
2211 		ret = update_qgroup_info_item(trans, qgroup);
2212 		if (ret)
2213 			fs_info->qgroup_flags |=
2214 					BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2215 		ret = update_qgroup_limit_item(trans, qgroup);
2216 		if (ret)
2217 			fs_info->qgroup_flags |=
2218 					BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2219 		spin_lock(&fs_info->qgroup_lock);
2220 	}
2221 	if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2222 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_ON;
2223 	else
2224 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
2225 	spin_unlock(&fs_info->qgroup_lock);
2226 
2227 	ret = update_qgroup_status_item(trans);
2228 	if (ret)
2229 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2230 
2231 	return ret;
2232 }
2233 
2234 /*
2235  * Copy the accounting information between qgroups. This is necessary
2236  * when a snapshot or a subvolume is created. Throwing an error will
2237  * cause a transaction abort so we take extra care here to only error
2238  * when a readonly fs is a reasonable outcome.
2239  */
2240 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
2241 			 u64 objectid, struct btrfs_qgroup_inherit *inherit)
2242 {
2243 	int ret = 0;
2244 	int i;
2245 	u64 *i_qgroups;
2246 	struct btrfs_fs_info *fs_info = trans->fs_info;
2247 	struct btrfs_root *quota_root = fs_info->quota_root;
2248 	struct btrfs_qgroup *srcgroup;
2249 	struct btrfs_qgroup *dstgroup;
2250 	u32 level_size = 0;
2251 	u64 nums;
2252 
2253 	mutex_lock(&fs_info->qgroup_ioctl_lock);
2254 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2255 		goto out;
2256 
2257 	if (!quota_root) {
2258 		ret = -EINVAL;
2259 		goto out;
2260 	}
2261 
2262 	if (inherit) {
2263 		i_qgroups = (u64 *)(inherit + 1);
2264 		nums = inherit->num_qgroups + 2 * inherit->num_ref_copies +
2265 		       2 * inherit->num_excl_copies;
2266 		for (i = 0; i < nums; ++i) {
2267 			srcgroup = find_qgroup_rb(fs_info, *i_qgroups);
2268 
2269 			/*
2270 			 * Zero out invalid groups so we can ignore
2271 			 * them later.
2272 			 */
2273 			if (!srcgroup ||
2274 			    ((srcgroup->qgroupid >> 48) <= (objectid >> 48)))
2275 				*i_qgroups = 0ULL;
2276 
2277 			++i_qgroups;
2278 		}
2279 	}
2280 
2281 	/*
2282 	 * create a tracking group for the subvol itself
2283 	 */
2284 	ret = add_qgroup_item(trans, quota_root, objectid);
2285 	if (ret)
2286 		goto out;
2287 
2288 	/*
2289 	 * add qgroup to all inherited groups
2290 	 */
2291 	if (inherit) {
2292 		i_qgroups = (u64 *)(inherit + 1);
2293 		for (i = 0; i < inherit->num_qgroups; ++i, ++i_qgroups) {
2294 			if (*i_qgroups == 0)
2295 				continue;
2296 			ret = add_qgroup_relation_item(trans, objectid,
2297 						       *i_qgroups);
2298 			if (ret && ret != -EEXIST)
2299 				goto out;
2300 			ret = add_qgroup_relation_item(trans, *i_qgroups,
2301 						       objectid);
2302 			if (ret && ret != -EEXIST)
2303 				goto out;
2304 		}
2305 		ret = 0;
2306 	}
2307 
2308 
2309 	spin_lock(&fs_info->qgroup_lock);
2310 
2311 	dstgroup = add_qgroup_rb(fs_info, objectid);
2312 	if (IS_ERR(dstgroup)) {
2313 		ret = PTR_ERR(dstgroup);
2314 		goto unlock;
2315 	}
2316 
2317 	if (inherit && inherit->flags & BTRFS_QGROUP_INHERIT_SET_LIMITS) {
2318 		dstgroup->lim_flags = inherit->lim.flags;
2319 		dstgroup->max_rfer = inherit->lim.max_rfer;
2320 		dstgroup->max_excl = inherit->lim.max_excl;
2321 		dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
2322 		dstgroup->rsv_excl = inherit->lim.rsv_excl;
2323 
2324 		ret = update_qgroup_limit_item(trans, dstgroup);
2325 		if (ret) {
2326 			fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2327 			btrfs_info(fs_info,
2328 				   "unable to update quota limit for %llu",
2329 				   dstgroup->qgroupid);
2330 			goto unlock;
2331 		}
2332 	}
2333 
2334 	if (srcid) {
2335 		srcgroup = find_qgroup_rb(fs_info, srcid);
2336 		if (!srcgroup)
2337 			goto unlock;
2338 
2339 		/*
2340 		 * We call inherit after we clone the root in order to make sure
2341 		 * our counts don't go crazy, so at this point the only
2342 		 * difference between the two roots should be the root node.
2343 		 */
2344 		level_size = fs_info->nodesize;
2345 		dstgroup->rfer = srcgroup->rfer;
2346 		dstgroup->rfer_cmpr = srcgroup->rfer_cmpr;
2347 		dstgroup->excl = level_size;
2348 		dstgroup->excl_cmpr = level_size;
2349 		srcgroup->excl = level_size;
2350 		srcgroup->excl_cmpr = level_size;
2351 
2352 		/* inherit the limit info */
2353 		dstgroup->lim_flags = srcgroup->lim_flags;
2354 		dstgroup->max_rfer = srcgroup->max_rfer;
2355 		dstgroup->max_excl = srcgroup->max_excl;
2356 		dstgroup->rsv_rfer = srcgroup->rsv_rfer;
2357 		dstgroup->rsv_excl = srcgroup->rsv_excl;
2358 
2359 		qgroup_dirty(fs_info, dstgroup);
2360 		qgroup_dirty(fs_info, srcgroup);
2361 	}
2362 
2363 	if (!inherit)
2364 		goto unlock;
2365 
2366 	i_qgroups = (u64 *)(inherit + 1);
2367 	for (i = 0; i < inherit->num_qgroups; ++i) {
2368 		if (*i_qgroups) {
2369 			ret = add_relation_rb(fs_info, objectid, *i_qgroups);
2370 			if (ret)
2371 				goto unlock;
2372 		}
2373 		++i_qgroups;
2374 	}
2375 
2376 	for (i = 0; i <  inherit->num_ref_copies; ++i, i_qgroups += 2) {
2377 		struct btrfs_qgroup *src;
2378 		struct btrfs_qgroup *dst;
2379 
2380 		if (!i_qgroups[0] || !i_qgroups[1])
2381 			continue;
2382 
2383 		src = find_qgroup_rb(fs_info, i_qgroups[0]);
2384 		dst = find_qgroup_rb(fs_info, i_qgroups[1]);
2385 
2386 		if (!src || !dst) {
2387 			ret = -EINVAL;
2388 			goto unlock;
2389 		}
2390 
2391 		dst->rfer = src->rfer - level_size;
2392 		dst->rfer_cmpr = src->rfer_cmpr - level_size;
2393 	}
2394 	for (i = 0; i <  inherit->num_excl_copies; ++i, i_qgroups += 2) {
2395 		struct btrfs_qgroup *src;
2396 		struct btrfs_qgroup *dst;
2397 
2398 		if (!i_qgroups[0] || !i_qgroups[1])
2399 			continue;
2400 
2401 		src = find_qgroup_rb(fs_info, i_qgroups[0]);
2402 		dst = find_qgroup_rb(fs_info, i_qgroups[1]);
2403 
2404 		if (!src || !dst) {
2405 			ret = -EINVAL;
2406 			goto unlock;
2407 		}
2408 
2409 		dst->excl = src->excl + level_size;
2410 		dst->excl_cmpr = src->excl_cmpr + level_size;
2411 	}
2412 
2413 unlock:
2414 	spin_unlock(&fs_info->qgroup_lock);
2415 out:
2416 	mutex_unlock(&fs_info->qgroup_ioctl_lock);
2417 	return ret;
2418 }
2419 
2420 /*
2421  * Two limits to commit transaction in advance.
2422  *
2423  * For RATIO, it will be 1/RATIO of the remaining limit
2424  * (excluding data and prealloc meta) as threshold.
2425  * For SIZE, it will be in byte unit as threshold.
2426  */
2427 #define QGROUP_PERTRANS_RATIO		32
2428 #define QGROUP_PERTRANS_SIZE		SZ_32M
2429 static bool qgroup_check_limits(struct btrfs_fs_info *fs_info,
2430 				const struct btrfs_qgroup *qg, u64 num_bytes)
2431 {
2432 	u64 limit;
2433 	u64 threshold;
2434 
2435 	if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
2436 	    qgroup_rsv_total(qg) + (s64)qg->rfer + num_bytes > qg->max_rfer)
2437 		return false;
2438 
2439 	if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
2440 	    qgroup_rsv_total(qg) + (s64)qg->excl + num_bytes > qg->max_excl)
2441 		return false;
2442 
2443 	/*
2444 	 * Even if we passed the check, it's better to check if reservation
2445 	 * for meta_pertrans is pushing us near limit.
2446 	 * If there is too much pertrans reservation or it's near the limit,
2447 	 * let's try commit transaction to free some, using transaction_kthread
2448 	 */
2449 	if ((qg->lim_flags & (BTRFS_QGROUP_LIMIT_MAX_RFER |
2450 			      BTRFS_QGROUP_LIMIT_MAX_EXCL))) {
2451 		if (qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL)
2452 			limit = qg->max_excl;
2453 		else
2454 			limit = qg->max_rfer;
2455 		threshold = (limit - qg->rsv.values[BTRFS_QGROUP_RSV_DATA] -
2456 			    qg->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC]) /
2457 			    QGROUP_PERTRANS_RATIO;
2458 		threshold = min_t(u64, threshold, QGROUP_PERTRANS_SIZE);
2459 
2460 		/*
2461 		 * Use transaction_kthread to commit transaction, so we no
2462 		 * longer need to bother nested transaction nor lock context.
2463 		 */
2464 		if (qg->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS] > threshold)
2465 			btrfs_commit_transaction_locksafe(fs_info);
2466 	}
2467 
2468 	return true;
2469 }
2470 
2471 static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce,
2472 			  enum btrfs_qgroup_rsv_type type)
2473 {
2474 	struct btrfs_root *quota_root;
2475 	struct btrfs_qgroup *qgroup;
2476 	struct btrfs_fs_info *fs_info = root->fs_info;
2477 	u64 ref_root = root->root_key.objectid;
2478 	int ret = 0;
2479 	struct ulist_node *unode;
2480 	struct ulist_iterator uiter;
2481 
2482 	if (!is_fstree(ref_root))
2483 		return 0;
2484 
2485 	if (num_bytes == 0)
2486 		return 0;
2487 
2488 	if (test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags) &&
2489 	    capable(CAP_SYS_RESOURCE))
2490 		enforce = false;
2491 
2492 	spin_lock(&fs_info->qgroup_lock);
2493 	quota_root = fs_info->quota_root;
2494 	if (!quota_root)
2495 		goto out;
2496 
2497 	qgroup = find_qgroup_rb(fs_info, ref_root);
2498 	if (!qgroup)
2499 		goto out;
2500 
2501 	/*
2502 	 * in a first step, we check all affected qgroups if any limits would
2503 	 * be exceeded
2504 	 */
2505 	ulist_reinit(fs_info->qgroup_ulist);
2506 	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2507 			qgroup_to_aux(qgroup), GFP_ATOMIC);
2508 	if (ret < 0)
2509 		goto out;
2510 	ULIST_ITER_INIT(&uiter);
2511 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2512 		struct btrfs_qgroup *qg;
2513 		struct btrfs_qgroup_list *glist;
2514 
2515 		qg = unode_aux_to_qgroup(unode);
2516 
2517 		if (enforce && !qgroup_check_limits(fs_info, qg, num_bytes)) {
2518 			ret = -EDQUOT;
2519 			goto out;
2520 		}
2521 
2522 		list_for_each_entry(glist, &qg->groups, next_group) {
2523 			ret = ulist_add(fs_info->qgroup_ulist,
2524 					glist->group->qgroupid,
2525 					qgroup_to_aux(glist->group), GFP_ATOMIC);
2526 			if (ret < 0)
2527 				goto out;
2528 		}
2529 	}
2530 	ret = 0;
2531 	/*
2532 	 * no limits exceeded, now record the reservation into all qgroups
2533 	 */
2534 	ULIST_ITER_INIT(&uiter);
2535 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2536 		struct btrfs_qgroup *qg;
2537 
2538 		qg = unode_aux_to_qgroup(unode);
2539 
2540 		trace_qgroup_update_reserve(fs_info, qg, num_bytes, type);
2541 		qgroup_rsv_add(fs_info, qg, num_bytes, type);
2542 	}
2543 
2544 out:
2545 	spin_unlock(&fs_info->qgroup_lock);
2546 	return ret;
2547 }
2548 
2549 /*
2550  * Free @num_bytes of reserved space with @type for qgroup.  (Normally level 0
2551  * qgroup).
2552  *
2553  * Will handle all higher level qgroup too.
2554  *
2555  * NOTE: If @num_bytes is (u64)-1, this means to free all bytes of this qgroup.
2556  * This special case is only used for META_PERTRANS type.
2557  */
2558 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
2559 			       u64 ref_root, u64 num_bytes,
2560 			       enum btrfs_qgroup_rsv_type type)
2561 {
2562 	struct btrfs_root *quota_root;
2563 	struct btrfs_qgroup *qgroup;
2564 	struct ulist_node *unode;
2565 	struct ulist_iterator uiter;
2566 	int ret = 0;
2567 
2568 	if (!is_fstree(ref_root))
2569 		return;
2570 
2571 	if (num_bytes == 0)
2572 		return;
2573 
2574 	if (num_bytes == (u64)-1 && type != BTRFS_QGROUP_RSV_META_PERTRANS) {
2575 		WARN(1, "%s: Invalid type to free", __func__);
2576 		return;
2577 	}
2578 	spin_lock(&fs_info->qgroup_lock);
2579 
2580 	quota_root = fs_info->quota_root;
2581 	if (!quota_root)
2582 		goto out;
2583 
2584 	qgroup = find_qgroup_rb(fs_info, ref_root);
2585 	if (!qgroup)
2586 		goto out;
2587 
2588 	if (num_bytes == (u64)-1)
2589 		/*
2590 		 * We're freeing all pertrans rsv, get reserved value from
2591 		 * level 0 qgroup as real num_bytes to free.
2592 		 */
2593 		num_bytes = qgroup->rsv.values[type];
2594 
2595 	ulist_reinit(fs_info->qgroup_ulist);
2596 	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2597 			qgroup_to_aux(qgroup), GFP_ATOMIC);
2598 	if (ret < 0)
2599 		goto out;
2600 	ULIST_ITER_INIT(&uiter);
2601 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2602 		struct btrfs_qgroup *qg;
2603 		struct btrfs_qgroup_list *glist;
2604 
2605 		qg = unode_aux_to_qgroup(unode);
2606 
2607 		trace_qgroup_update_reserve(fs_info, qg, -(s64)num_bytes, type);
2608 		qgroup_rsv_release(fs_info, qg, num_bytes, type);
2609 
2610 		list_for_each_entry(glist, &qg->groups, next_group) {
2611 			ret = ulist_add(fs_info->qgroup_ulist,
2612 					glist->group->qgroupid,
2613 					qgroup_to_aux(glist->group), GFP_ATOMIC);
2614 			if (ret < 0)
2615 				goto out;
2616 		}
2617 	}
2618 
2619 out:
2620 	spin_unlock(&fs_info->qgroup_lock);
2621 }
2622 
2623 /*
2624  * Check if the leaf is the last leaf. Which means all node pointers
2625  * are at their last position.
2626  */
2627 static bool is_last_leaf(struct btrfs_path *path)
2628 {
2629 	int i;
2630 
2631 	for (i = 1; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
2632 		if (path->slots[i] != btrfs_header_nritems(path->nodes[i]) - 1)
2633 			return false;
2634 	}
2635 	return true;
2636 }
2637 
2638 /*
2639  * returns < 0 on error, 0 when more leafs are to be scanned.
2640  * returns 1 when done.
2641  */
2642 static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
2643 			      struct btrfs_path *path)
2644 {
2645 	struct btrfs_fs_info *fs_info = trans->fs_info;
2646 	struct btrfs_key found;
2647 	struct extent_buffer *scratch_leaf = NULL;
2648 	struct ulist *roots = NULL;
2649 	u64 num_bytes;
2650 	bool done;
2651 	int slot;
2652 	int ret;
2653 
2654 	mutex_lock(&fs_info->qgroup_rescan_lock);
2655 	ret = btrfs_search_slot_for_read(fs_info->extent_root,
2656 					 &fs_info->qgroup_rescan_progress,
2657 					 path, 1, 0);
2658 
2659 	btrfs_debug(fs_info,
2660 		"current progress key (%llu %u %llu), search_slot ret %d",
2661 		fs_info->qgroup_rescan_progress.objectid,
2662 		fs_info->qgroup_rescan_progress.type,
2663 		fs_info->qgroup_rescan_progress.offset, ret);
2664 
2665 	if (ret) {
2666 		/*
2667 		 * The rescan is about to end, we will not be scanning any
2668 		 * further blocks. We cannot unset the RESCAN flag here, because
2669 		 * we want to commit the transaction if everything went well.
2670 		 * To make the live accounting work in this phase, we set our
2671 		 * scan progress pointer such that every real extent objectid
2672 		 * will be smaller.
2673 		 */
2674 		fs_info->qgroup_rescan_progress.objectid = (u64)-1;
2675 		btrfs_release_path(path);
2676 		mutex_unlock(&fs_info->qgroup_rescan_lock);
2677 		return ret;
2678 	}
2679 	done = is_last_leaf(path);
2680 
2681 	btrfs_item_key_to_cpu(path->nodes[0], &found,
2682 			      btrfs_header_nritems(path->nodes[0]) - 1);
2683 	fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
2684 
2685 	scratch_leaf = btrfs_clone_extent_buffer(path->nodes[0]);
2686 	if (!scratch_leaf) {
2687 		ret = -ENOMEM;
2688 		mutex_unlock(&fs_info->qgroup_rescan_lock);
2689 		goto out;
2690 	}
2691 	extent_buffer_get(scratch_leaf);
2692 	btrfs_tree_read_lock(scratch_leaf);
2693 	btrfs_set_lock_blocking_rw(scratch_leaf, BTRFS_READ_LOCK);
2694 	slot = path->slots[0];
2695 	btrfs_release_path(path);
2696 	mutex_unlock(&fs_info->qgroup_rescan_lock);
2697 
2698 	for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
2699 		btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
2700 		if (found.type != BTRFS_EXTENT_ITEM_KEY &&
2701 		    found.type != BTRFS_METADATA_ITEM_KEY)
2702 			continue;
2703 		if (found.type == BTRFS_METADATA_ITEM_KEY)
2704 			num_bytes = fs_info->nodesize;
2705 		else
2706 			num_bytes = found.offset;
2707 
2708 		ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0,
2709 					   &roots, false);
2710 		if (ret < 0)
2711 			goto out;
2712 		/* For rescan, just pass old_roots as NULL */
2713 		ret = btrfs_qgroup_account_extent(trans, found.objectid,
2714 						  num_bytes, NULL, roots);
2715 		if (ret < 0)
2716 			goto out;
2717 	}
2718 out:
2719 	if (scratch_leaf) {
2720 		btrfs_tree_read_unlock_blocking(scratch_leaf);
2721 		free_extent_buffer(scratch_leaf);
2722 	}
2723 
2724 	if (done && !ret) {
2725 		ret = 1;
2726 		fs_info->qgroup_rescan_progress.objectid = (u64)-1;
2727 	}
2728 	return ret;
2729 }
2730 
2731 static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
2732 {
2733 	struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
2734 						     qgroup_rescan_work);
2735 	struct btrfs_path *path;
2736 	struct btrfs_trans_handle *trans = NULL;
2737 	int err = -ENOMEM;
2738 	int ret = 0;
2739 
2740 	path = btrfs_alloc_path();
2741 	if (!path)
2742 		goto out;
2743 	/*
2744 	 * Rescan should only search for commit root, and any later difference
2745 	 * should be recorded by qgroup
2746 	 */
2747 	path->search_commit_root = 1;
2748 	path->skip_locking = 1;
2749 
2750 	err = 0;
2751 	while (!err && !btrfs_fs_closing(fs_info)) {
2752 		trans = btrfs_start_transaction(fs_info->fs_root, 0);
2753 		if (IS_ERR(trans)) {
2754 			err = PTR_ERR(trans);
2755 			break;
2756 		}
2757 		if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
2758 			err = -EINTR;
2759 		} else {
2760 			err = qgroup_rescan_leaf(trans, path);
2761 		}
2762 		if (err > 0)
2763 			btrfs_commit_transaction(trans);
2764 		else
2765 			btrfs_end_transaction(trans);
2766 	}
2767 
2768 out:
2769 	btrfs_free_path(path);
2770 
2771 	mutex_lock(&fs_info->qgroup_rescan_lock);
2772 	if (!btrfs_fs_closing(fs_info))
2773 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
2774 
2775 	if (err > 0 &&
2776 	    fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
2777 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2778 	} else if (err < 0) {
2779 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2780 	}
2781 	mutex_unlock(&fs_info->qgroup_rescan_lock);
2782 
2783 	/*
2784 	 * only update status, since the previous part has already updated the
2785 	 * qgroup info.
2786 	 */
2787 	trans = btrfs_start_transaction(fs_info->quota_root, 1);
2788 	if (IS_ERR(trans)) {
2789 		err = PTR_ERR(trans);
2790 		btrfs_err(fs_info,
2791 			  "fail to start transaction for status update: %d",
2792 			  err);
2793 		goto done;
2794 	}
2795 	ret = update_qgroup_status_item(trans);
2796 	if (ret < 0) {
2797 		err = ret;
2798 		btrfs_err(fs_info, "fail to update qgroup status: %d", err);
2799 	}
2800 	btrfs_end_transaction(trans);
2801 
2802 	if (btrfs_fs_closing(fs_info)) {
2803 		btrfs_info(fs_info, "qgroup scan paused");
2804 	} else if (err >= 0) {
2805 		btrfs_info(fs_info, "qgroup scan completed%s",
2806 			err > 0 ? " (inconsistency flag cleared)" : "");
2807 	} else {
2808 		btrfs_err(fs_info, "qgroup scan failed with %d", err);
2809 	}
2810 
2811 done:
2812 	mutex_lock(&fs_info->qgroup_rescan_lock);
2813 	fs_info->qgroup_rescan_running = false;
2814 	mutex_unlock(&fs_info->qgroup_rescan_lock);
2815 	complete_all(&fs_info->qgroup_rescan_completion);
2816 }
2817 
2818 /*
2819  * Checks that (a) no rescan is running and (b) quota is enabled. Allocates all
2820  * memory required for the rescan context.
2821  */
2822 static int
2823 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
2824 		   int init_flags)
2825 {
2826 	int ret = 0;
2827 
2828 	if (!init_flags) {
2829 		/* we're resuming qgroup rescan at mount time */
2830 		if (!(fs_info->qgroup_flags &
2831 		      BTRFS_QGROUP_STATUS_FLAG_RESCAN)) {
2832 			btrfs_warn(fs_info,
2833 			"qgroup rescan init failed, qgroup is not enabled");
2834 			ret = -EINVAL;
2835 		} else if (!(fs_info->qgroup_flags &
2836 			     BTRFS_QGROUP_STATUS_FLAG_ON)) {
2837 			btrfs_warn(fs_info,
2838 			"qgroup rescan init failed, qgroup rescan is not queued");
2839 			ret = -EINVAL;
2840 		}
2841 
2842 		if (ret)
2843 			return ret;
2844 	}
2845 
2846 	mutex_lock(&fs_info->qgroup_rescan_lock);
2847 	spin_lock(&fs_info->qgroup_lock);
2848 
2849 	if (init_flags) {
2850 		if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
2851 			btrfs_warn(fs_info,
2852 				   "qgroup rescan is already in progress");
2853 			ret = -EINPROGRESS;
2854 		} else if (!(fs_info->qgroup_flags &
2855 			     BTRFS_QGROUP_STATUS_FLAG_ON)) {
2856 			btrfs_warn(fs_info,
2857 			"qgroup rescan init failed, qgroup is not enabled");
2858 			ret = -EINVAL;
2859 		}
2860 
2861 		if (ret) {
2862 			spin_unlock(&fs_info->qgroup_lock);
2863 			mutex_unlock(&fs_info->qgroup_rescan_lock);
2864 			return ret;
2865 		}
2866 		fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
2867 	}
2868 
2869 	memset(&fs_info->qgroup_rescan_progress, 0,
2870 		sizeof(fs_info->qgroup_rescan_progress));
2871 	fs_info->qgroup_rescan_progress.objectid = progress_objectid;
2872 	init_completion(&fs_info->qgroup_rescan_completion);
2873 	fs_info->qgroup_rescan_running = true;
2874 
2875 	spin_unlock(&fs_info->qgroup_lock);
2876 	mutex_unlock(&fs_info->qgroup_rescan_lock);
2877 
2878 	memset(&fs_info->qgroup_rescan_work, 0,
2879 	       sizeof(fs_info->qgroup_rescan_work));
2880 	btrfs_init_work(&fs_info->qgroup_rescan_work,
2881 			btrfs_qgroup_rescan_helper,
2882 			btrfs_qgroup_rescan_worker, NULL, NULL);
2883 	return 0;
2884 }
2885 
2886 static void
2887 qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info)
2888 {
2889 	struct rb_node *n;
2890 	struct btrfs_qgroup *qgroup;
2891 
2892 	spin_lock(&fs_info->qgroup_lock);
2893 	/* clear all current qgroup tracking information */
2894 	for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
2895 		qgroup = rb_entry(n, struct btrfs_qgroup, node);
2896 		qgroup->rfer = 0;
2897 		qgroup->rfer_cmpr = 0;
2898 		qgroup->excl = 0;
2899 		qgroup->excl_cmpr = 0;
2900 	}
2901 	spin_unlock(&fs_info->qgroup_lock);
2902 }
2903 
2904 int
2905 btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
2906 {
2907 	int ret = 0;
2908 	struct btrfs_trans_handle *trans;
2909 
2910 	ret = qgroup_rescan_init(fs_info, 0, 1);
2911 	if (ret)
2912 		return ret;
2913 
2914 	/*
2915 	 * We have set the rescan_progress to 0, which means no more
2916 	 * delayed refs will be accounted by btrfs_qgroup_account_ref.
2917 	 * However, btrfs_qgroup_account_ref may be right after its call
2918 	 * to btrfs_find_all_roots, in which case it would still do the
2919 	 * accounting.
2920 	 * To solve this, we're committing the transaction, which will
2921 	 * ensure we run all delayed refs and only after that, we are
2922 	 * going to clear all tracking information for a clean start.
2923 	 */
2924 
2925 	trans = btrfs_join_transaction(fs_info->fs_root);
2926 	if (IS_ERR(trans)) {
2927 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
2928 		return PTR_ERR(trans);
2929 	}
2930 	ret = btrfs_commit_transaction(trans);
2931 	if (ret) {
2932 		fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
2933 		return ret;
2934 	}
2935 
2936 	qgroup_rescan_zero_tracking(fs_info);
2937 
2938 	btrfs_queue_work(fs_info->qgroup_rescan_workers,
2939 			 &fs_info->qgroup_rescan_work);
2940 
2941 	return 0;
2942 }
2943 
2944 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
2945 				     bool interruptible)
2946 {
2947 	int running;
2948 	int ret = 0;
2949 
2950 	mutex_lock(&fs_info->qgroup_rescan_lock);
2951 	spin_lock(&fs_info->qgroup_lock);
2952 	running = fs_info->qgroup_rescan_running;
2953 	spin_unlock(&fs_info->qgroup_lock);
2954 	mutex_unlock(&fs_info->qgroup_rescan_lock);
2955 
2956 	if (!running)
2957 		return 0;
2958 
2959 	if (interruptible)
2960 		ret = wait_for_completion_interruptible(
2961 					&fs_info->qgroup_rescan_completion);
2962 	else
2963 		wait_for_completion(&fs_info->qgroup_rescan_completion);
2964 
2965 	return ret;
2966 }
2967 
2968 /*
2969  * this is only called from open_ctree where we're still single threaded, thus
2970  * locking is omitted here.
2971  */
2972 void
2973 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
2974 {
2975 	if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
2976 		btrfs_queue_work(fs_info->qgroup_rescan_workers,
2977 				 &fs_info->qgroup_rescan_work);
2978 }
2979 
2980 /*
2981  * Reserve qgroup space for range [start, start + len).
2982  *
2983  * This function will either reserve space from related qgroups or doing
2984  * nothing if the range is already reserved.
2985  *
2986  * Return 0 for successful reserve
2987  * Return <0 for error (including -EQUOT)
2988  *
2989  * NOTE: this function may sleep for memory allocation.
2990  *       if btrfs_qgroup_reserve_data() is called multiple times with
2991  *       same @reserved, caller must ensure when error happens it's OK
2992  *       to free *ALL* reserved space.
2993  */
2994 int btrfs_qgroup_reserve_data(struct inode *inode,
2995 			struct extent_changeset **reserved_ret, u64 start,
2996 			u64 len)
2997 {
2998 	struct btrfs_root *root = BTRFS_I(inode)->root;
2999 	struct ulist_node *unode;
3000 	struct ulist_iterator uiter;
3001 	struct extent_changeset *reserved;
3002 	u64 orig_reserved;
3003 	u64 to_reserve;
3004 	int ret;
3005 
3006 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags) ||
3007 	    !is_fstree(root->objectid) || len == 0)
3008 		return 0;
3009 
3010 	/* @reserved parameter is mandatory for qgroup */
3011 	if (WARN_ON(!reserved_ret))
3012 		return -EINVAL;
3013 	if (!*reserved_ret) {
3014 		*reserved_ret = extent_changeset_alloc();
3015 		if (!*reserved_ret)
3016 			return -ENOMEM;
3017 	}
3018 	reserved = *reserved_ret;
3019 	/* Record already reserved space */
3020 	orig_reserved = reserved->bytes_changed;
3021 	ret = set_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
3022 			start + len -1, EXTENT_QGROUP_RESERVED, reserved);
3023 
3024 	/* Newly reserved space */
3025 	to_reserve = reserved->bytes_changed - orig_reserved;
3026 	trace_btrfs_qgroup_reserve_data(inode, start, len,
3027 					to_reserve, QGROUP_RESERVE);
3028 	if (ret < 0)
3029 		goto cleanup;
3030 	ret = qgroup_reserve(root, to_reserve, true, BTRFS_QGROUP_RSV_DATA);
3031 	if (ret < 0)
3032 		goto cleanup;
3033 
3034 	return ret;
3035 
3036 cleanup:
3037 	/* cleanup *ALL* already reserved ranges */
3038 	ULIST_ITER_INIT(&uiter);
3039 	while ((unode = ulist_next(&reserved->range_changed, &uiter)))
3040 		clear_extent_bit(&BTRFS_I(inode)->io_tree, unode->val,
3041 				 unode->aux, EXTENT_QGROUP_RESERVED, 0, 0, NULL);
3042 	extent_changeset_release(reserved);
3043 	return ret;
3044 }
3045 
3046 /* Free ranges specified by @reserved, normally in error path */
3047 static int qgroup_free_reserved_data(struct inode *inode,
3048 			struct extent_changeset *reserved, u64 start, u64 len)
3049 {
3050 	struct btrfs_root *root = BTRFS_I(inode)->root;
3051 	struct ulist_node *unode;
3052 	struct ulist_iterator uiter;
3053 	struct extent_changeset changeset;
3054 	int freed = 0;
3055 	int ret;
3056 
3057 	extent_changeset_init(&changeset);
3058 	len = round_up(start + len, root->fs_info->sectorsize);
3059 	start = round_down(start, root->fs_info->sectorsize);
3060 
3061 	ULIST_ITER_INIT(&uiter);
3062 	while ((unode = ulist_next(&reserved->range_changed, &uiter))) {
3063 		u64 range_start = unode->val;
3064 		/* unode->aux is the inclusive end */
3065 		u64 range_len = unode->aux - range_start + 1;
3066 		u64 free_start;
3067 		u64 free_len;
3068 
3069 		extent_changeset_release(&changeset);
3070 
3071 		/* Only free range in range [start, start + len) */
3072 		if (range_start >= start + len ||
3073 		    range_start + range_len <= start)
3074 			continue;
3075 		free_start = max(range_start, start);
3076 		free_len = min(start + len, range_start + range_len) -
3077 			   free_start;
3078 		/*
3079 		 * TODO: To also modify reserved->ranges_reserved to reflect
3080 		 * the modification.
3081 		 *
3082 		 * However as long as we free qgroup reserved according to
3083 		 * EXTENT_QGROUP_RESERVED, we won't double free.
3084 		 * So not need to rush.
3085 		 */
3086 		ret = clear_record_extent_bits(&BTRFS_I(inode)->io_failure_tree,
3087 				free_start, free_start + free_len - 1,
3088 				EXTENT_QGROUP_RESERVED, &changeset);
3089 		if (ret < 0)
3090 			goto out;
3091 		freed += changeset.bytes_changed;
3092 	}
3093 	btrfs_qgroup_free_refroot(root->fs_info, root->objectid, freed,
3094 				  BTRFS_QGROUP_RSV_DATA);
3095 	ret = freed;
3096 out:
3097 	extent_changeset_release(&changeset);
3098 	return ret;
3099 }
3100 
3101 static int __btrfs_qgroup_release_data(struct inode *inode,
3102 			struct extent_changeset *reserved, u64 start, u64 len,
3103 			int free)
3104 {
3105 	struct extent_changeset changeset;
3106 	int trace_op = QGROUP_RELEASE;
3107 	int ret;
3108 
3109 	/* In release case, we shouldn't have @reserved */
3110 	WARN_ON(!free && reserved);
3111 	if (free && reserved)
3112 		return qgroup_free_reserved_data(inode, reserved, start, len);
3113 	extent_changeset_init(&changeset);
3114 	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
3115 			start + len -1, EXTENT_QGROUP_RESERVED, &changeset);
3116 	if (ret < 0)
3117 		goto out;
3118 
3119 	if (free)
3120 		trace_op = QGROUP_FREE;
3121 	trace_btrfs_qgroup_release_data(inode, start, len,
3122 					changeset.bytes_changed, trace_op);
3123 	if (free)
3124 		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3125 				BTRFS_I(inode)->root->objectid,
3126 				changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3127 	ret = changeset.bytes_changed;
3128 out:
3129 	extent_changeset_release(&changeset);
3130 	return ret;
3131 }
3132 
3133 /*
3134  * Free a reserved space range from io_tree and related qgroups
3135  *
3136  * Should be called when a range of pages get invalidated before reaching disk.
3137  * Or for error cleanup case.
3138  * if @reserved is given, only reserved range in [@start, @start + @len) will
3139  * be freed.
3140  *
3141  * For data written to disk, use btrfs_qgroup_release_data().
3142  *
3143  * NOTE: This function may sleep for memory allocation.
3144  */
3145 int btrfs_qgroup_free_data(struct inode *inode,
3146 			struct extent_changeset *reserved, u64 start, u64 len)
3147 {
3148 	return __btrfs_qgroup_release_data(inode, reserved, start, len, 1);
3149 }
3150 
3151 /*
3152  * Release a reserved space range from io_tree only.
3153  *
3154  * Should be called when a range of pages get written to disk and corresponding
3155  * FILE_EXTENT is inserted into corresponding root.
3156  *
3157  * Since new qgroup accounting framework will only update qgroup numbers at
3158  * commit_transaction() time, its reserved space shouldn't be freed from
3159  * related qgroups.
3160  *
3161  * But we should release the range from io_tree, to allow further write to be
3162  * COWed.
3163  *
3164  * NOTE: This function may sleep for memory allocation.
3165  */
3166 int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len)
3167 {
3168 	return __btrfs_qgroup_release_data(inode, NULL, start, len, 0);
3169 }
3170 
3171 static void add_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3172 			      enum btrfs_qgroup_rsv_type type)
3173 {
3174 	if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3175 	    type != BTRFS_QGROUP_RSV_META_PERTRANS)
3176 		return;
3177 	if (num_bytes == 0)
3178 		return;
3179 
3180 	spin_lock(&root->qgroup_meta_rsv_lock);
3181 	if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
3182 		root->qgroup_meta_rsv_prealloc += num_bytes;
3183 	else
3184 		root->qgroup_meta_rsv_pertrans += num_bytes;
3185 	spin_unlock(&root->qgroup_meta_rsv_lock);
3186 }
3187 
3188 static int sub_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3189 			     enum btrfs_qgroup_rsv_type type)
3190 {
3191 	if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3192 	    type != BTRFS_QGROUP_RSV_META_PERTRANS)
3193 		return 0;
3194 	if (num_bytes == 0)
3195 		return 0;
3196 
3197 	spin_lock(&root->qgroup_meta_rsv_lock);
3198 	if (type == BTRFS_QGROUP_RSV_META_PREALLOC) {
3199 		num_bytes = min_t(u64, root->qgroup_meta_rsv_prealloc,
3200 				  num_bytes);
3201 		root->qgroup_meta_rsv_prealloc -= num_bytes;
3202 	} else {
3203 		num_bytes = min_t(u64, root->qgroup_meta_rsv_pertrans,
3204 				  num_bytes);
3205 		root->qgroup_meta_rsv_pertrans -= num_bytes;
3206 	}
3207 	spin_unlock(&root->qgroup_meta_rsv_lock);
3208 	return num_bytes;
3209 }
3210 
3211 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
3212 				enum btrfs_qgroup_rsv_type type, bool enforce)
3213 {
3214 	struct btrfs_fs_info *fs_info = root->fs_info;
3215 	int ret;
3216 
3217 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3218 	    !is_fstree(root->objectid) || num_bytes == 0)
3219 		return 0;
3220 
3221 	BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3222 	trace_qgroup_meta_reserve(root, type, (s64)num_bytes);
3223 	ret = qgroup_reserve(root, num_bytes, enforce, type);
3224 	if (ret < 0)
3225 		return ret;
3226 	/*
3227 	 * Record what we have reserved into root.
3228 	 *
3229 	 * To avoid quota disabled->enabled underflow.
3230 	 * In that case, we may try to free space we haven't reserved
3231 	 * (since quota was disabled), so record what we reserved into root.
3232 	 * And ensure later release won't underflow this number.
3233 	 */
3234 	add_root_meta_rsv(root, num_bytes, type);
3235 	return ret;
3236 }
3237 
3238 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root)
3239 {
3240 	struct btrfs_fs_info *fs_info = root->fs_info;
3241 
3242 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3243 	    !is_fstree(root->objectid))
3244 		return;
3245 
3246 	/* TODO: Update trace point to handle such free */
3247 	trace_qgroup_meta_free_all_pertrans(root);
3248 	/* Special value -1 means to free all reserved space */
3249 	btrfs_qgroup_free_refroot(fs_info, root->objectid, (u64)-1,
3250 				  BTRFS_QGROUP_RSV_META_PERTRANS);
3251 }
3252 
3253 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
3254 			      enum btrfs_qgroup_rsv_type type)
3255 {
3256 	struct btrfs_fs_info *fs_info = root->fs_info;
3257 
3258 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3259 	    !is_fstree(root->objectid))
3260 		return;
3261 
3262 	/*
3263 	 * reservation for META_PREALLOC can happen before quota is enabled,
3264 	 * which can lead to underflow.
3265 	 * Here ensure we will only free what we really have reserved.
3266 	 */
3267 	num_bytes = sub_root_meta_rsv(root, num_bytes, type);
3268 	BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3269 	trace_qgroup_meta_reserve(root, type, -(s64)num_bytes);
3270 	btrfs_qgroup_free_refroot(fs_info, root->objectid, num_bytes, type);
3271 }
3272 
3273 static void qgroup_convert_meta(struct btrfs_fs_info *fs_info, u64 ref_root,
3274 				int num_bytes)
3275 {
3276 	struct btrfs_root *quota_root = fs_info->quota_root;
3277 	struct btrfs_qgroup *qgroup;
3278 	struct ulist_node *unode;
3279 	struct ulist_iterator uiter;
3280 	int ret = 0;
3281 
3282 	if (num_bytes == 0)
3283 		return;
3284 	if (!quota_root)
3285 		return;
3286 
3287 	spin_lock(&fs_info->qgroup_lock);
3288 	qgroup = find_qgroup_rb(fs_info, ref_root);
3289 	if (!qgroup)
3290 		goto out;
3291 	ulist_reinit(fs_info->qgroup_ulist);
3292 	ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
3293 		       qgroup_to_aux(qgroup), GFP_ATOMIC);
3294 	if (ret < 0)
3295 		goto out;
3296 	ULIST_ITER_INIT(&uiter);
3297 	while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
3298 		struct btrfs_qgroup *qg;
3299 		struct btrfs_qgroup_list *glist;
3300 
3301 		qg = unode_aux_to_qgroup(unode);
3302 
3303 		qgroup_rsv_release(fs_info, qg, num_bytes,
3304 				BTRFS_QGROUP_RSV_META_PREALLOC);
3305 		qgroup_rsv_add(fs_info, qg, num_bytes,
3306 				BTRFS_QGROUP_RSV_META_PERTRANS);
3307 		list_for_each_entry(glist, &qg->groups, next_group) {
3308 			ret = ulist_add(fs_info->qgroup_ulist,
3309 					glist->group->qgroupid,
3310 					qgroup_to_aux(glist->group), GFP_ATOMIC);
3311 			if (ret < 0)
3312 				goto out;
3313 		}
3314 	}
3315 out:
3316 	spin_unlock(&fs_info->qgroup_lock);
3317 }
3318 
3319 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes)
3320 {
3321 	struct btrfs_fs_info *fs_info = root->fs_info;
3322 
3323 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3324 	    !is_fstree(root->objectid))
3325 		return;
3326 	/* Same as btrfs_qgroup_free_meta_prealloc() */
3327 	num_bytes = sub_root_meta_rsv(root, num_bytes,
3328 				      BTRFS_QGROUP_RSV_META_PREALLOC);
3329 	trace_qgroup_meta_convert(root, num_bytes);
3330 	qgroup_convert_meta(fs_info, root->objectid, num_bytes);
3331 }
3332 
3333 /*
3334  * Check qgroup reserved space leaking, normally at destroy inode
3335  * time
3336  */
3337 void btrfs_qgroup_check_reserved_leak(struct inode *inode)
3338 {
3339 	struct extent_changeset changeset;
3340 	struct ulist_node *unode;
3341 	struct ulist_iterator iter;
3342 	int ret;
3343 
3344 	extent_changeset_init(&changeset);
3345 	ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, 0, (u64)-1,
3346 			EXTENT_QGROUP_RESERVED, &changeset);
3347 
3348 	WARN_ON(ret < 0);
3349 	if (WARN_ON(changeset.bytes_changed)) {
3350 		ULIST_ITER_INIT(&iter);
3351 		while ((unode = ulist_next(&changeset.range_changed, &iter))) {
3352 			btrfs_warn(BTRFS_I(inode)->root->fs_info,
3353 				"leaking qgroup reserved space, ino: %lu, start: %llu, end: %llu",
3354 				inode->i_ino, unode->val, unode->aux);
3355 		}
3356 		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3357 				BTRFS_I(inode)->root->objectid,
3358 				changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3359 
3360 	}
3361 	extent_changeset_release(&changeset);
3362 }
3363