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TOMOYO Linux Cross Reference
Linux/fs/btrfs/qgroup.c

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  1 // SPDX-License-Identifier: GPL-2.0
  2 /*
  3  * Copyright (C) 2011 STRATO.  All rights reserved.
  4  */
  5 
  6 #include <linux/sched.h>
  7 #include <linux/pagemap.h>
  8 #include <linux/writeback.h>
  9 #include <linux/blkdev.h>
 10 #include <linux/rbtree.h>
 11 #include <linux/slab.h>
 12 #include <linux/workqueue.h>
 13 #include <linux/btrfs.h>
 14 #include <linux/sizes.h>
 15 
 16 #include "ctree.h"
 17 #include "transaction.h"
 18 #include "disk-io.h"
 19 #include "locking.h"
 20 #include "ulist.h"
 21 #include "backref.h"
 22 #include "extent_io.h"
 23 #include "qgroup.h"
 24 
 25 
 26 /* TODO XXX FIXME
 27  *  - subvol delete -> delete when ref goes to 0? delete limits also?
 28  *  - reorganize keys
 29  *  - compressed
 30  *  - sync
 31  *  - copy also limits on subvol creation
 32  *  - limit
 33  *  - caches for ulists
 34  *  - performance benchmarks
 35  *  - check all ioctl parameters
 36  */
 37 
 38 /*
 39  * Helpers to access qgroup reservation
 40  *
 41  * Callers should ensure the lock context and type are valid
 42  */
 43 
 44 static u64 qgroup_rsv_total(const struct btrfs_qgroup *qgroup)
 45 {
 46         u64 ret = 0;
 47         int i;
 48 
 49         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
 50                 ret += qgroup->rsv.values[i];
 51 
 52         return ret;
 53 }
 54 
 55 #ifdef CONFIG_BTRFS_DEBUG
 56 static const char *qgroup_rsv_type_str(enum btrfs_qgroup_rsv_type type)
 57 {
 58         if (type == BTRFS_QGROUP_RSV_DATA)
 59                 return "data";
 60         if (type == BTRFS_QGROUP_RSV_META_PERTRANS)
 61                 return "meta_pertrans";
 62         if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
 63                 return "meta_prealloc";
 64         return NULL;
 65 }
 66 #endif
 67 
 68 static void qgroup_rsv_add(struct btrfs_fs_info *fs_info,
 69                            struct btrfs_qgroup *qgroup, u64 num_bytes,
 70                            enum btrfs_qgroup_rsv_type type)
 71 {
 72         trace_qgroup_update_reserve(fs_info, qgroup, num_bytes, type);
 73         qgroup->rsv.values[type] += num_bytes;
 74 }
 75 
 76 static void qgroup_rsv_release(struct btrfs_fs_info *fs_info,
 77                                struct btrfs_qgroup *qgroup, u64 num_bytes,
 78                                enum btrfs_qgroup_rsv_type type)
 79 {
 80         trace_qgroup_update_reserve(fs_info, qgroup, -(s64)num_bytes, type);
 81         if (qgroup->rsv.values[type] >= num_bytes) {
 82                 qgroup->rsv.values[type] -= num_bytes;
 83                 return;
 84         }
 85 #ifdef CONFIG_BTRFS_DEBUG
 86         WARN_RATELIMIT(1,
 87                 "qgroup %llu %s reserved space underflow, have %llu to free %llu",
 88                 qgroup->qgroupid, qgroup_rsv_type_str(type),
 89                 qgroup->rsv.values[type], num_bytes);
 90 #endif
 91         qgroup->rsv.values[type] = 0;
 92 }
 93 
 94 static void qgroup_rsv_add_by_qgroup(struct btrfs_fs_info *fs_info,
 95                                      struct btrfs_qgroup *dest,
 96                                      struct btrfs_qgroup *src)
 97 {
 98         int i;
 99 
100         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
101                 qgroup_rsv_add(fs_info, dest, src->rsv.values[i], i);
102 }
103 
104 static void qgroup_rsv_release_by_qgroup(struct btrfs_fs_info *fs_info,
105                                          struct btrfs_qgroup *dest,
106                                           struct btrfs_qgroup *src)
107 {
108         int i;
109 
110         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
111                 qgroup_rsv_release(fs_info, dest, src->rsv.values[i], i);
112 }
113 
114 static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,
115                                            int mod)
116 {
117         if (qg->old_refcnt < seq)
118                 qg->old_refcnt = seq;
119         qg->old_refcnt += mod;
120 }
121 
122 static void btrfs_qgroup_update_new_refcnt(struct btrfs_qgroup *qg, u64 seq,
123                                            int mod)
124 {
125         if (qg->new_refcnt < seq)
126                 qg->new_refcnt = seq;
127         qg->new_refcnt += mod;
128 }
129 
130 static inline u64 btrfs_qgroup_get_old_refcnt(struct btrfs_qgroup *qg, u64 seq)
131 {
132         if (qg->old_refcnt < seq)
133                 return 0;
134         return qg->old_refcnt - seq;
135 }
136 
137 static inline u64 btrfs_qgroup_get_new_refcnt(struct btrfs_qgroup *qg, u64 seq)
138 {
139         if (qg->new_refcnt < seq)
140                 return 0;
141         return qg->new_refcnt - seq;
142 }
143 
144 /*
145  * glue structure to represent the relations between qgroups.
146  */
147 struct btrfs_qgroup_list {
148         struct list_head next_group;
149         struct list_head next_member;
150         struct btrfs_qgroup *group;
151         struct btrfs_qgroup *member;
152 };
153 
154 static inline u64 qgroup_to_aux(struct btrfs_qgroup *qg)
155 {
156         return (u64)(uintptr_t)qg;
157 }
158 
159 static inline struct btrfs_qgroup* unode_aux_to_qgroup(struct ulist_node *n)
160 {
161         return (struct btrfs_qgroup *)(uintptr_t)n->aux;
162 }
163 
164 static int
165 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
166                    int init_flags);
167 static void qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info);
168 
169 /* must be called with qgroup_ioctl_lock held */
170 static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
171                                            u64 qgroupid)
172 {
173         struct rb_node *n = fs_info->qgroup_tree.rb_node;
174         struct btrfs_qgroup *qgroup;
175 
176         while (n) {
177                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
178                 if (qgroup->qgroupid < qgroupid)
179                         n = n->rb_left;
180                 else if (qgroup->qgroupid > qgroupid)
181                         n = n->rb_right;
182                 else
183                         return qgroup;
184         }
185         return NULL;
186 }
187 
188 /* must be called with qgroup_lock held */
189 static struct btrfs_qgroup *add_qgroup_rb(struct btrfs_fs_info *fs_info,
190                                           u64 qgroupid)
191 {
192         struct rb_node **p = &fs_info->qgroup_tree.rb_node;
193         struct rb_node *parent = NULL;
194         struct btrfs_qgroup *qgroup;
195 
196         while (*p) {
197                 parent = *p;
198                 qgroup = rb_entry(parent, struct btrfs_qgroup, node);
199 
200                 if (qgroup->qgroupid < qgroupid)
201                         p = &(*p)->rb_left;
202                 else if (qgroup->qgroupid > qgroupid)
203                         p = &(*p)->rb_right;
204                 else
205                         return qgroup;
206         }
207 
208         qgroup = kzalloc(sizeof(*qgroup), GFP_ATOMIC);
209         if (!qgroup)
210                 return ERR_PTR(-ENOMEM);
211 
212         qgroup->qgroupid = qgroupid;
213         INIT_LIST_HEAD(&qgroup->groups);
214         INIT_LIST_HEAD(&qgroup->members);
215         INIT_LIST_HEAD(&qgroup->dirty);
216 
217         rb_link_node(&qgroup->node, parent, p);
218         rb_insert_color(&qgroup->node, &fs_info->qgroup_tree);
219 
220         return qgroup;
221 }
222 
223 static void __del_qgroup_rb(struct btrfs_qgroup *qgroup)
224 {
225         struct btrfs_qgroup_list *list;
226 
227         list_del(&qgroup->dirty);
228         while (!list_empty(&qgroup->groups)) {
229                 list = list_first_entry(&qgroup->groups,
230                                         struct btrfs_qgroup_list, next_group);
231                 list_del(&list->next_group);
232                 list_del(&list->next_member);
233                 kfree(list);
234         }
235 
236         while (!list_empty(&qgroup->members)) {
237                 list = list_first_entry(&qgroup->members,
238                                         struct btrfs_qgroup_list, next_member);
239                 list_del(&list->next_group);
240                 list_del(&list->next_member);
241                 kfree(list);
242         }
243         kfree(qgroup);
244 }
245 
246 /* must be called with qgroup_lock held */
247 static int del_qgroup_rb(struct btrfs_fs_info *fs_info, u64 qgroupid)
248 {
249         struct btrfs_qgroup *qgroup = find_qgroup_rb(fs_info, qgroupid);
250 
251         if (!qgroup)
252                 return -ENOENT;
253 
254         rb_erase(&qgroup->node, &fs_info->qgroup_tree);
255         __del_qgroup_rb(qgroup);
256         return 0;
257 }
258 
259 /* must be called with qgroup_lock held */
260 static int add_relation_rb(struct btrfs_fs_info *fs_info,
261                            u64 memberid, u64 parentid)
262 {
263         struct btrfs_qgroup *member;
264         struct btrfs_qgroup *parent;
265         struct btrfs_qgroup_list *list;
266 
267         member = find_qgroup_rb(fs_info, memberid);
268         parent = find_qgroup_rb(fs_info, parentid);
269         if (!member || !parent)
270                 return -ENOENT;
271 
272         list = kzalloc(sizeof(*list), GFP_ATOMIC);
273         if (!list)
274                 return -ENOMEM;
275 
276         list->group = parent;
277         list->member = member;
278         list_add_tail(&list->next_group, &member->groups);
279         list_add_tail(&list->next_member, &parent->members);
280 
281         return 0;
282 }
283 
284 /* must be called with qgroup_lock held */
285 static int del_relation_rb(struct btrfs_fs_info *fs_info,
286                            u64 memberid, u64 parentid)
287 {
288         struct btrfs_qgroup *member;
289         struct btrfs_qgroup *parent;
290         struct btrfs_qgroup_list *list;
291 
292         member = find_qgroup_rb(fs_info, memberid);
293         parent = find_qgroup_rb(fs_info, parentid);
294         if (!member || !parent)
295                 return -ENOENT;
296 
297         list_for_each_entry(list, &member->groups, next_group) {
298                 if (list->group == parent) {
299                         list_del(&list->next_group);
300                         list_del(&list->next_member);
301                         kfree(list);
302                         return 0;
303                 }
304         }
305         return -ENOENT;
306 }
307 
308 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
309 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
310                                u64 rfer, u64 excl)
311 {
312         struct btrfs_qgroup *qgroup;
313 
314         qgroup = find_qgroup_rb(fs_info, qgroupid);
315         if (!qgroup)
316                 return -EINVAL;
317         if (qgroup->rfer != rfer || qgroup->excl != excl)
318                 return -EINVAL;
319         return 0;
320 }
321 #endif
322 
323 /*
324  * The full config is read in one go, only called from open_ctree()
325  * It doesn't use any locking, as at this point we're still single-threaded
326  */
327 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
328 {
329         struct btrfs_key key;
330         struct btrfs_key found_key;
331         struct btrfs_root *quota_root = fs_info->quota_root;
332         struct btrfs_path *path = NULL;
333         struct extent_buffer *l;
334         int slot;
335         int ret = 0;
336         u64 flags = 0;
337         u64 rescan_progress = 0;
338 
339         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
340                 return 0;
341 
342         fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
343         if (!fs_info->qgroup_ulist) {
344                 ret = -ENOMEM;
345                 goto out;
346         }
347 
348         path = btrfs_alloc_path();
349         if (!path) {
350                 ret = -ENOMEM;
351                 goto out;
352         }
353 
354         /* default this to quota off, in case no status key is found */
355         fs_info->qgroup_flags = 0;
356 
357         /*
358          * pass 1: read status, all qgroup infos and limits
359          */
360         key.objectid = 0;
361         key.type = 0;
362         key.offset = 0;
363         ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 1);
364         if (ret)
365                 goto out;
366 
367         while (1) {
368                 struct btrfs_qgroup *qgroup;
369 
370                 slot = path->slots[0];
371                 l = path->nodes[0];
372                 btrfs_item_key_to_cpu(l, &found_key, slot);
373 
374                 if (found_key.type == BTRFS_QGROUP_STATUS_KEY) {
375                         struct btrfs_qgroup_status_item *ptr;
376 
377                         ptr = btrfs_item_ptr(l, slot,
378                                              struct btrfs_qgroup_status_item);
379 
380                         if (btrfs_qgroup_status_version(l, ptr) !=
381                             BTRFS_QGROUP_STATUS_VERSION) {
382                                 btrfs_err(fs_info,
383                                  "old qgroup version, quota disabled");
384                                 goto out;
385                         }
386                         if (btrfs_qgroup_status_generation(l, ptr) !=
387                             fs_info->generation) {
388                                 flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
389                                 btrfs_err(fs_info,
390                                         "qgroup generation mismatch, marked as inconsistent");
391                         }
392                         fs_info->qgroup_flags = btrfs_qgroup_status_flags(l,
393                                                                           ptr);
394                         rescan_progress = btrfs_qgroup_status_rescan(l, ptr);
395                         goto next1;
396                 }
397 
398                 if (found_key.type != BTRFS_QGROUP_INFO_KEY &&
399                     found_key.type != BTRFS_QGROUP_LIMIT_KEY)
400                         goto next1;
401 
402                 qgroup = find_qgroup_rb(fs_info, found_key.offset);
403                 if ((qgroup && found_key.type == BTRFS_QGROUP_INFO_KEY) ||
404                     (!qgroup && found_key.type == BTRFS_QGROUP_LIMIT_KEY)) {
405                         btrfs_err(fs_info, "inconsistent qgroup config");
406                         flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
407                 }
408                 if (!qgroup) {
409                         qgroup = add_qgroup_rb(fs_info, found_key.offset);
410                         if (IS_ERR(qgroup)) {
411                                 ret = PTR_ERR(qgroup);
412                                 goto out;
413                         }
414                 }
415                 switch (found_key.type) {
416                 case BTRFS_QGROUP_INFO_KEY: {
417                         struct btrfs_qgroup_info_item *ptr;
418 
419                         ptr = btrfs_item_ptr(l, slot,
420                                              struct btrfs_qgroup_info_item);
421                         qgroup->rfer = btrfs_qgroup_info_rfer(l, ptr);
422                         qgroup->rfer_cmpr = btrfs_qgroup_info_rfer_cmpr(l, ptr);
423                         qgroup->excl = btrfs_qgroup_info_excl(l, ptr);
424                         qgroup->excl_cmpr = btrfs_qgroup_info_excl_cmpr(l, ptr);
425                         /* generation currently unused */
426                         break;
427                 }
428                 case BTRFS_QGROUP_LIMIT_KEY: {
429                         struct btrfs_qgroup_limit_item *ptr;
430 
431                         ptr = btrfs_item_ptr(l, slot,
432                                              struct btrfs_qgroup_limit_item);
433                         qgroup->lim_flags = btrfs_qgroup_limit_flags(l, ptr);
434                         qgroup->max_rfer = btrfs_qgroup_limit_max_rfer(l, ptr);
435                         qgroup->max_excl = btrfs_qgroup_limit_max_excl(l, ptr);
436                         qgroup->rsv_rfer = btrfs_qgroup_limit_rsv_rfer(l, ptr);
437                         qgroup->rsv_excl = btrfs_qgroup_limit_rsv_excl(l, ptr);
438                         break;
439                 }
440                 }
441 next1:
442                 ret = btrfs_next_item(quota_root, path);
443                 if (ret < 0)
444                         goto out;
445                 if (ret)
446                         break;
447         }
448         btrfs_release_path(path);
449 
450         /*
451          * pass 2: read all qgroup relations
452          */
453         key.objectid = 0;
454         key.type = BTRFS_QGROUP_RELATION_KEY;
455         key.offset = 0;
456         ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 0);
457         if (ret)
458                 goto out;
459         while (1) {
460                 slot = path->slots[0];
461                 l = path->nodes[0];
462                 btrfs_item_key_to_cpu(l, &found_key, slot);
463 
464                 if (found_key.type != BTRFS_QGROUP_RELATION_KEY)
465                         goto next2;
466 
467                 if (found_key.objectid > found_key.offset) {
468                         /* parent <- member, not needed to build config */
469                         /* FIXME should we omit the key completely? */
470                         goto next2;
471                 }
472 
473                 ret = add_relation_rb(fs_info, found_key.objectid,
474                                       found_key.offset);
475                 if (ret == -ENOENT) {
476                         btrfs_warn(fs_info,
477                                 "orphan qgroup relation 0x%llx->0x%llx",
478                                 found_key.objectid, found_key.offset);
479                         ret = 0;        /* ignore the error */
480                 }
481                 if (ret)
482                         goto out;
483 next2:
484                 ret = btrfs_next_item(quota_root, path);
485                 if (ret < 0)
486                         goto out;
487                 if (ret)
488                         break;
489         }
490 out:
491         fs_info->qgroup_flags |= flags;
492         if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON))
493                 clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
494         else if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN &&
495                  ret >= 0)
496                 ret = qgroup_rescan_init(fs_info, rescan_progress, 0);
497         btrfs_free_path(path);
498 
499         if (ret < 0) {
500                 ulist_free(fs_info->qgroup_ulist);
501                 fs_info->qgroup_ulist = NULL;
502                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
503         }
504 
505         return ret < 0 ? ret : 0;
506 }
507 
508 /*
509  * This is called from close_ctree() or open_ctree() or btrfs_quota_disable(),
510  * first two are in single-threaded paths.And for the third one, we have set
511  * quota_root to be null with qgroup_lock held before, so it is safe to clean
512  * up the in-memory structures without qgroup_lock held.
513  */
514 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
515 {
516         struct rb_node *n;
517         struct btrfs_qgroup *qgroup;
518 
519         while ((n = rb_first(&fs_info->qgroup_tree))) {
520                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
521                 rb_erase(n, &fs_info->qgroup_tree);
522                 __del_qgroup_rb(qgroup);
523         }
524         /*
525          * We call btrfs_free_qgroup_config() when unmounting
526          * filesystem and disabling quota, so we set qgroup_ulist
527          * to be null here to avoid double free.
528          */
529         ulist_free(fs_info->qgroup_ulist);
530         fs_info->qgroup_ulist = NULL;
531 }
532 
533 static int add_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
534                                     u64 dst)
535 {
536         int ret;
537         struct btrfs_root *quota_root = trans->fs_info->quota_root;
538         struct btrfs_path *path;
539         struct btrfs_key key;
540 
541         path = btrfs_alloc_path();
542         if (!path)
543                 return -ENOMEM;
544 
545         key.objectid = src;
546         key.type = BTRFS_QGROUP_RELATION_KEY;
547         key.offset = dst;
548 
549         ret = btrfs_insert_empty_item(trans, quota_root, path, &key, 0);
550 
551         btrfs_mark_buffer_dirty(path->nodes[0]);
552 
553         btrfs_free_path(path);
554         return ret;
555 }
556 
557 static int del_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
558                                     u64 dst)
559 {
560         int ret;
561         struct btrfs_root *quota_root = trans->fs_info->quota_root;
562         struct btrfs_path *path;
563         struct btrfs_key key;
564 
565         path = btrfs_alloc_path();
566         if (!path)
567                 return -ENOMEM;
568 
569         key.objectid = src;
570         key.type = BTRFS_QGROUP_RELATION_KEY;
571         key.offset = dst;
572 
573         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
574         if (ret < 0)
575                 goto out;
576 
577         if (ret > 0) {
578                 ret = -ENOENT;
579                 goto out;
580         }
581 
582         ret = btrfs_del_item(trans, quota_root, path);
583 out:
584         btrfs_free_path(path);
585         return ret;
586 }
587 
588 static int add_qgroup_item(struct btrfs_trans_handle *trans,
589                            struct btrfs_root *quota_root, u64 qgroupid)
590 {
591         int ret;
592         struct btrfs_path *path;
593         struct btrfs_qgroup_info_item *qgroup_info;
594         struct btrfs_qgroup_limit_item *qgroup_limit;
595         struct extent_buffer *leaf;
596         struct btrfs_key key;
597 
598         if (btrfs_is_testing(quota_root->fs_info))
599                 return 0;
600 
601         path = btrfs_alloc_path();
602         if (!path)
603                 return -ENOMEM;
604 
605         key.objectid = 0;
606         key.type = BTRFS_QGROUP_INFO_KEY;
607         key.offset = qgroupid;
608 
609         /*
610          * Avoid a transaction abort by catching -EEXIST here. In that
611          * case, we proceed by re-initializing the existing structure
612          * on disk.
613          */
614 
615         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
616                                       sizeof(*qgroup_info));
617         if (ret && ret != -EEXIST)
618                 goto out;
619 
620         leaf = path->nodes[0];
621         qgroup_info = btrfs_item_ptr(leaf, path->slots[0],
622                                  struct btrfs_qgroup_info_item);
623         btrfs_set_qgroup_info_generation(leaf, qgroup_info, trans->transid);
624         btrfs_set_qgroup_info_rfer(leaf, qgroup_info, 0);
625         btrfs_set_qgroup_info_rfer_cmpr(leaf, qgroup_info, 0);
626         btrfs_set_qgroup_info_excl(leaf, qgroup_info, 0);
627         btrfs_set_qgroup_info_excl_cmpr(leaf, qgroup_info, 0);
628 
629         btrfs_mark_buffer_dirty(leaf);
630 
631         btrfs_release_path(path);
632 
633         key.type = BTRFS_QGROUP_LIMIT_KEY;
634         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
635                                       sizeof(*qgroup_limit));
636         if (ret && ret != -EEXIST)
637                 goto out;
638 
639         leaf = path->nodes[0];
640         qgroup_limit = btrfs_item_ptr(leaf, path->slots[0],
641                                   struct btrfs_qgroup_limit_item);
642         btrfs_set_qgroup_limit_flags(leaf, qgroup_limit, 0);
643         btrfs_set_qgroup_limit_max_rfer(leaf, qgroup_limit, 0);
644         btrfs_set_qgroup_limit_max_excl(leaf, qgroup_limit, 0);
645         btrfs_set_qgroup_limit_rsv_rfer(leaf, qgroup_limit, 0);
646         btrfs_set_qgroup_limit_rsv_excl(leaf, qgroup_limit, 0);
647 
648         btrfs_mark_buffer_dirty(leaf);
649 
650         ret = 0;
651 out:
652         btrfs_free_path(path);
653         return ret;
654 }
655 
656 static int del_qgroup_item(struct btrfs_trans_handle *trans, u64 qgroupid)
657 {
658         int ret;
659         struct btrfs_root *quota_root = trans->fs_info->quota_root;
660         struct btrfs_path *path;
661         struct btrfs_key key;
662 
663         path = btrfs_alloc_path();
664         if (!path)
665                 return -ENOMEM;
666 
667         key.objectid = 0;
668         key.type = BTRFS_QGROUP_INFO_KEY;
669         key.offset = qgroupid;
670         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
671         if (ret < 0)
672                 goto out;
673 
674         if (ret > 0) {
675                 ret = -ENOENT;
676                 goto out;
677         }
678 
679         ret = btrfs_del_item(trans, quota_root, path);
680         if (ret)
681                 goto out;
682 
683         btrfs_release_path(path);
684 
685         key.type = BTRFS_QGROUP_LIMIT_KEY;
686         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
687         if (ret < 0)
688                 goto out;
689 
690         if (ret > 0) {
691                 ret = -ENOENT;
692                 goto out;
693         }
694 
695         ret = btrfs_del_item(trans, quota_root, path);
696 
697 out:
698         btrfs_free_path(path);
699         return ret;
700 }
701 
702 static int update_qgroup_limit_item(struct btrfs_trans_handle *trans,
703                                     struct btrfs_qgroup *qgroup)
704 {
705         struct btrfs_root *quota_root = trans->fs_info->quota_root;
706         struct btrfs_path *path;
707         struct btrfs_key key;
708         struct extent_buffer *l;
709         struct btrfs_qgroup_limit_item *qgroup_limit;
710         int ret;
711         int slot;
712 
713         key.objectid = 0;
714         key.type = BTRFS_QGROUP_LIMIT_KEY;
715         key.offset = qgroup->qgroupid;
716 
717         path = btrfs_alloc_path();
718         if (!path)
719                 return -ENOMEM;
720 
721         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
722         if (ret > 0)
723                 ret = -ENOENT;
724 
725         if (ret)
726                 goto out;
727 
728         l = path->nodes[0];
729         slot = path->slots[0];
730         qgroup_limit = btrfs_item_ptr(l, slot, struct btrfs_qgroup_limit_item);
731         btrfs_set_qgroup_limit_flags(l, qgroup_limit, qgroup->lim_flags);
732         btrfs_set_qgroup_limit_max_rfer(l, qgroup_limit, qgroup->max_rfer);
733         btrfs_set_qgroup_limit_max_excl(l, qgroup_limit, qgroup->max_excl);
734         btrfs_set_qgroup_limit_rsv_rfer(l, qgroup_limit, qgroup->rsv_rfer);
735         btrfs_set_qgroup_limit_rsv_excl(l, qgroup_limit, qgroup->rsv_excl);
736 
737         btrfs_mark_buffer_dirty(l);
738 
739 out:
740         btrfs_free_path(path);
741         return ret;
742 }
743 
744 static int update_qgroup_info_item(struct btrfs_trans_handle *trans,
745                                    struct btrfs_qgroup *qgroup)
746 {
747         struct btrfs_fs_info *fs_info = trans->fs_info;
748         struct btrfs_root *quota_root = fs_info->quota_root;
749         struct btrfs_path *path;
750         struct btrfs_key key;
751         struct extent_buffer *l;
752         struct btrfs_qgroup_info_item *qgroup_info;
753         int ret;
754         int slot;
755 
756         if (btrfs_is_testing(fs_info))
757                 return 0;
758 
759         key.objectid = 0;
760         key.type = BTRFS_QGROUP_INFO_KEY;
761         key.offset = qgroup->qgroupid;
762 
763         path = btrfs_alloc_path();
764         if (!path)
765                 return -ENOMEM;
766 
767         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
768         if (ret > 0)
769                 ret = -ENOENT;
770 
771         if (ret)
772                 goto out;
773 
774         l = path->nodes[0];
775         slot = path->slots[0];
776         qgroup_info = btrfs_item_ptr(l, slot, struct btrfs_qgroup_info_item);
777         btrfs_set_qgroup_info_generation(l, qgroup_info, trans->transid);
778         btrfs_set_qgroup_info_rfer(l, qgroup_info, qgroup->rfer);
779         btrfs_set_qgroup_info_rfer_cmpr(l, qgroup_info, qgroup->rfer_cmpr);
780         btrfs_set_qgroup_info_excl(l, qgroup_info, qgroup->excl);
781         btrfs_set_qgroup_info_excl_cmpr(l, qgroup_info, qgroup->excl_cmpr);
782 
783         btrfs_mark_buffer_dirty(l);
784 
785 out:
786         btrfs_free_path(path);
787         return ret;
788 }
789 
790 static int update_qgroup_status_item(struct btrfs_trans_handle *trans)
791 {
792         struct btrfs_fs_info *fs_info = trans->fs_info;
793         struct btrfs_root *quota_root = fs_info->quota_root;
794         struct btrfs_path *path;
795         struct btrfs_key key;
796         struct extent_buffer *l;
797         struct btrfs_qgroup_status_item *ptr;
798         int ret;
799         int slot;
800 
801         key.objectid = 0;
802         key.type = BTRFS_QGROUP_STATUS_KEY;
803         key.offset = 0;
804 
805         path = btrfs_alloc_path();
806         if (!path)
807                 return -ENOMEM;
808 
809         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
810         if (ret > 0)
811                 ret = -ENOENT;
812 
813         if (ret)
814                 goto out;
815 
816         l = path->nodes[0];
817         slot = path->slots[0];
818         ptr = btrfs_item_ptr(l, slot, struct btrfs_qgroup_status_item);
819         btrfs_set_qgroup_status_flags(l, ptr, fs_info->qgroup_flags);
820         btrfs_set_qgroup_status_generation(l, ptr, trans->transid);
821         btrfs_set_qgroup_status_rescan(l, ptr,
822                                 fs_info->qgroup_rescan_progress.objectid);
823 
824         btrfs_mark_buffer_dirty(l);
825 
826 out:
827         btrfs_free_path(path);
828         return ret;
829 }
830 
831 /*
832  * called with qgroup_lock held
833  */
834 static int btrfs_clean_quota_tree(struct btrfs_trans_handle *trans,
835                                   struct btrfs_root *root)
836 {
837         struct btrfs_path *path;
838         struct btrfs_key key;
839         struct extent_buffer *leaf = NULL;
840         int ret;
841         int nr = 0;
842 
843         path = btrfs_alloc_path();
844         if (!path)
845                 return -ENOMEM;
846 
847         path->leave_spinning = 1;
848 
849         key.objectid = 0;
850         key.offset = 0;
851         key.type = 0;
852 
853         while (1) {
854                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
855                 if (ret < 0)
856                         goto out;
857                 leaf = path->nodes[0];
858                 nr = btrfs_header_nritems(leaf);
859                 if (!nr)
860                         break;
861                 /*
862                  * delete the leaf one by one
863                  * since the whole tree is going
864                  * to be deleted.
865                  */
866                 path->slots[0] = 0;
867                 ret = btrfs_del_items(trans, root, path, 0, nr);
868                 if (ret)
869                         goto out;
870 
871                 btrfs_release_path(path);
872         }
873         ret = 0;
874 out:
875         btrfs_free_path(path);
876         return ret;
877 }
878 
879 int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
880 {
881         struct btrfs_root *quota_root;
882         struct btrfs_root *tree_root = fs_info->tree_root;
883         struct btrfs_path *path = NULL;
884         struct btrfs_qgroup_status_item *ptr;
885         struct extent_buffer *leaf;
886         struct btrfs_key key;
887         struct btrfs_key found_key;
888         struct btrfs_qgroup *qgroup = NULL;
889         struct btrfs_trans_handle *trans = NULL;
890         int ret = 0;
891         int slot;
892 
893         mutex_lock(&fs_info->qgroup_ioctl_lock);
894         if (fs_info->quota_root)
895                 goto out;
896 
897         fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
898         if (!fs_info->qgroup_ulist) {
899                 ret = -ENOMEM;
900                 goto out;
901         }
902 
903         /*
904          * 1 for quota root item
905          * 1 for BTRFS_QGROUP_STATUS item
906          *
907          * Yet we also need 2*n items for a QGROUP_INFO/QGROUP_LIMIT items
908          * per subvolume. However those are not currently reserved since it
909          * would be a lot of overkill.
910          */
911         trans = btrfs_start_transaction(tree_root, 2);
912         if (IS_ERR(trans)) {
913                 ret = PTR_ERR(trans);
914                 trans = NULL;
915                 goto out;
916         }
917 
918         /*
919          * initially create the quota tree
920          */
921         quota_root = btrfs_create_tree(trans, BTRFS_QUOTA_TREE_OBJECTID);
922         if (IS_ERR(quota_root)) {
923                 ret =  PTR_ERR(quota_root);
924                 btrfs_abort_transaction(trans, ret);
925                 goto out;
926         }
927 
928         path = btrfs_alloc_path();
929         if (!path) {
930                 ret = -ENOMEM;
931                 btrfs_abort_transaction(trans, ret);
932                 goto out_free_root;
933         }
934 
935         key.objectid = 0;
936         key.type = BTRFS_QGROUP_STATUS_KEY;
937         key.offset = 0;
938 
939         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
940                                       sizeof(*ptr));
941         if (ret) {
942                 btrfs_abort_transaction(trans, ret);
943                 goto out_free_path;
944         }
945 
946         leaf = path->nodes[0];
947         ptr = btrfs_item_ptr(leaf, path->slots[0],
948                                  struct btrfs_qgroup_status_item);
949         btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
950         btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
951         fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON |
952                                 BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
953         btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags);
954         btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
955 
956         btrfs_mark_buffer_dirty(leaf);
957 
958         key.objectid = 0;
959         key.type = BTRFS_ROOT_REF_KEY;
960         key.offset = 0;
961 
962         btrfs_release_path(path);
963         ret = btrfs_search_slot_for_read(tree_root, &key, path, 1, 0);
964         if (ret > 0)
965                 goto out_add_root;
966         if (ret < 0) {
967                 btrfs_abort_transaction(trans, ret);
968                 goto out_free_path;
969         }
970 
971         while (1) {
972                 slot = path->slots[0];
973                 leaf = path->nodes[0];
974                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
975 
976                 if (found_key.type == BTRFS_ROOT_REF_KEY) {
977                         ret = add_qgroup_item(trans, quota_root,
978                                               found_key.offset);
979                         if (ret) {
980                                 btrfs_abort_transaction(trans, ret);
981                                 goto out_free_path;
982                         }
983 
984                         qgroup = add_qgroup_rb(fs_info, found_key.offset);
985                         if (IS_ERR(qgroup)) {
986                                 ret = PTR_ERR(qgroup);
987                                 btrfs_abort_transaction(trans, ret);
988                                 goto out_free_path;
989                         }
990                 }
991                 ret = btrfs_next_item(tree_root, path);
992                 if (ret < 0) {
993                         btrfs_abort_transaction(trans, ret);
994                         goto out_free_path;
995                 }
996                 if (ret)
997                         break;
998         }
999 
1000 out_add_root:
1001         btrfs_release_path(path);
1002         ret = add_qgroup_item(trans, quota_root, BTRFS_FS_TREE_OBJECTID);
1003         if (ret) {
1004                 btrfs_abort_transaction(trans, ret);
1005                 goto out_free_path;
1006         }
1007 
1008         qgroup = add_qgroup_rb(fs_info, BTRFS_FS_TREE_OBJECTID);
1009         if (IS_ERR(qgroup)) {
1010                 ret = PTR_ERR(qgroup);
1011                 btrfs_abort_transaction(trans, ret);
1012                 goto out_free_path;
1013         }
1014 
1015         ret = btrfs_commit_transaction(trans);
1016         trans = NULL;
1017         if (ret)
1018                 goto out_free_path;
1019 
1020         /*
1021          * Set quota enabled flag after committing the transaction, to avoid
1022          * deadlocks on fs_info->qgroup_ioctl_lock with concurrent snapshot
1023          * creation.
1024          */
1025         spin_lock(&fs_info->qgroup_lock);
1026         fs_info->quota_root = quota_root;
1027         set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1028         spin_unlock(&fs_info->qgroup_lock);
1029 
1030         ret = qgroup_rescan_init(fs_info, 0, 1);
1031         if (!ret) {
1032                 qgroup_rescan_zero_tracking(fs_info);
1033                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
1034                                  &fs_info->qgroup_rescan_work);
1035         }
1036 
1037 out_free_path:
1038         btrfs_free_path(path);
1039 out_free_root:
1040         if (ret) {
1041                 free_extent_buffer(quota_root->node);
1042                 free_extent_buffer(quota_root->commit_root);
1043                 kfree(quota_root);
1044         }
1045 out:
1046         if (ret) {
1047                 ulist_free(fs_info->qgroup_ulist);
1048                 fs_info->qgroup_ulist = NULL;
1049                 if (trans)
1050                         btrfs_end_transaction(trans);
1051         }
1052         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1053         return ret;
1054 }
1055 
1056 int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
1057 {
1058         struct btrfs_root *quota_root;
1059         struct btrfs_trans_handle *trans = NULL;
1060         int ret = 0;
1061 
1062         mutex_lock(&fs_info->qgroup_ioctl_lock);
1063         if (!fs_info->quota_root)
1064                 goto out;
1065 
1066         /*
1067          * 1 For the root item
1068          *
1069          * We should also reserve enough items for the quota tree deletion in
1070          * btrfs_clean_quota_tree but this is not done.
1071          */
1072         trans = btrfs_start_transaction(fs_info->tree_root, 1);
1073         if (IS_ERR(trans)) {
1074                 ret = PTR_ERR(trans);
1075                 goto out;
1076         }
1077 
1078         clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1079         btrfs_qgroup_wait_for_completion(fs_info, false);
1080         spin_lock(&fs_info->qgroup_lock);
1081         quota_root = fs_info->quota_root;
1082         fs_info->quota_root = NULL;
1083         fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
1084         spin_unlock(&fs_info->qgroup_lock);
1085 
1086         btrfs_free_qgroup_config(fs_info);
1087 
1088         ret = btrfs_clean_quota_tree(trans, quota_root);
1089         if (ret) {
1090                 btrfs_abort_transaction(trans, ret);
1091                 goto end_trans;
1092         }
1093 
1094         ret = btrfs_del_root(trans, &quota_root->root_key);
1095         if (ret) {
1096                 btrfs_abort_transaction(trans, ret);
1097                 goto end_trans;
1098         }
1099 
1100         list_del(&quota_root->dirty_list);
1101 
1102         btrfs_tree_lock(quota_root->node);
1103         btrfs_clean_tree_block(quota_root->node);
1104         btrfs_tree_unlock(quota_root->node);
1105         btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1);
1106 
1107         free_extent_buffer(quota_root->node);
1108         free_extent_buffer(quota_root->commit_root);
1109         kfree(quota_root);
1110 
1111 end_trans:
1112         ret = btrfs_end_transaction(trans);
1113 out:
1114         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1115         return ret;
1116 }
1117 
1118 static void qgroup_dirty(struct btrfs_fs_info *fs_info,
1119                          struct btrfs_qgroup *qgroup)
1120 {
1121         if (list_empty(&qgroup->dirty))
1122                 list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
1123 }
1124 
1125 /*
1126  * The easy accounting, we're updating qgroup relationship whose child qgroup
1127  * only has exclusive extents.
1128  *
1129  * In this case, all exclusive extents will also be exclusive for parent, so
1130  * excl/rfer just get added/removed.
1131  *
1132  * So is qgroup reservation space, which should also be added/removed to
1133  * parent.
1134  * Or when child tries to release reservation space, parent will underflow its
1135  * reservation (for relationship adding case).
1136  *
1137  * Caller should hold fs_info->qgroup_lock.
1138  */
1139 static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
1140                                     struct ulist *tmp, u64 ref_root,
1141                                     struct btrfs_qgroup *src, int sign)
1142 {
1143         struct btrfs_qgroup *qgroup;
1144         struct btrfs_qgroup_list *glist;
1145         struct ulist_node *unode;
1146         struct ulist_iterator uiter;
1147         u64 num_bytes = src->excl;
1148         int ret = 0;
1149 
1150         qgroup = find_qgroup_rb(fs_info, ref_root);
1151         if (!qgroup)
1152                 goto out;
1153 
1154         qgroup->rfer += sign * num_bytes;
1155         qgroup->rfer_cmpr += sign * num_bytes;
1156 
1157         WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1158         qgroup->excl += sign * num_bytes;
1159         qgroup->excl_cmpr += sign * num_bytes;
1160 
1161         if (sign > 0)
1162                 qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1163         else
1164                 qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1165 
1166         qgroup_dirty(fs_info, qgroup);
1167 
1168         /* Get all of the parent groups that contain this qgroup */
1169         list_for_each_entry(glist, &qgroup->groups, next_group) {
1170                 ret = ulist_add(tmp, glist->group->qgroupid,
1171                                 qgroup_to_aux(glist->group), GFP_ATOMIC);
1172                 if (ret < 0)
1173                         goto out;
1174         }
1175 
1176         /* Iterate all of the parents and adjust their reference counts */
1177         ULIST_ITER_INIT(&uiter);
1178         while ((unode = ulist_next(tmp, &uiter))) {
1179                 qgroup = unode_aux_to_qgroup(unode);
1180                 qgroup->rfer += sign * num_bytes;
1181                 qgroup->rfer_cmpr += sign * num_bytes;
1182                 WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1183                 qgroup->excl += sign * num_bytes;
1184                 if (sign > 0)
1185                         qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1186                 else
1187                         qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1188                 qgroup->excl_cmpr += sign * num_bytes;
1189                 qgroup_dirty(fs_info, qgroup);
1190 
1191                 /* Add any parents of the parents */
1192                 list_for_each_entry(glist, &qgroup->groups, next_group) {
1193                         ret = ulist_add(tmp, glist->group->qgroupid,
1194                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
1195                         if (ret < 0)
1196                                 goto out;
1197                 }
1198         }
1199         ret = 0;
1200 out:
1201         return ret;
1202 }
1203 
1204 
1205 /*
1206  * Quick path for updating qgroup with only excl refs.
1207  *
1208  * In that case, just update all parent will be enough.
1209  * Or we needs to do a full rescan.
1210  * Caller should also hold fs_info->qgroup_lock.
1211  *
1212  * Return 0 for quick update, return >0 for need to full rescan
1213  * and mark INCONSISTENT flag.
1214  * Return < 0 for other error.
1215  */
1216 static int quick_update_accounting(struct btrfs_fs_info *fs_info,
1217                                    struct ulist *tmp, u64 src, u64 dst,
1218                                    int sign)
1219 {
1220         struct btrfs_qgroup *qgroup;
1221         int ret = 1;
1222         int err = 0;
1223 
1224         qgroup = find_qgroup_rb(fs_info, src);
1225         if (!qgroup)
1226                 goto out;
1227         if (qgroup->excl == qgroup->rfer) {
1228                 ret = 0;
1229                 err = __qgroup_excl_accounting(fs_info, tmp, dst,
1230                                                qgroup, sign);
1231                 if (err < 0) {
1232                         ret = err;
1233                         goto out;
1234                 }
1235         }
1236 out:
1237         if (ret)
1238                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1239         return ret;
1240 }
1241 
1242 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1243                               u64 dst)
1244 {
1245         struct btrfs_fs_info *fs_info = trans->fs_info;
1246         struct btrfs_root *quota_root;
1247         struct btrfs_qgroup *parent;
1248         struct btrfs_qgroup *member;
1249         struct btrfs_qgroup_list *list;
1250         struct ulist *tmp;
1251         int ret = 0;
1252 
1253         /* Check the level of src and dst first */
1254         if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
1255                 return -EINVAL;
1256 
1257         tmp = ulist_alloc(GFP_KERNEL);
1258         if (!tmp)
1259                 return -ENOMEM;
1260 
1261         mutex_lock(&fs_info->qgroup_ioctl_lock);
1262         quota_root = fs_info->quota_root;
1263         if (!quota_root) {
1264                 ret = -EINVAL;
1265                 goto out;
1266         }
1267         member = find_qgroup_rb(fs_info, src);
1268         parent = find_qgroup_rb(fs_info, dst);
1269         if (!member || !parent) {
1270                 ret = -EINVAL;
1271                 goto out;
1272         }
1273 
1274         /* check if such qgroup relation exist firstly */
1275         list_for_each_entry(list, &member->groups, next_group) {
1276                 if (list->group == parent) {
1277                         ret = -EEXIST;
1278                         goto out;
1279                 }
1280         }
1281 
1282         ret = add_qgroup_relation_item(trans, src, dst);
1283         if (ret)
1284                 goto out;
1285 
1286         ret = add_qgroup_relation_item(trans, dst, src);
1287         if (ret) {
1288                 del_qgroup_relation_item(trans, src, dst);
1289                 goto out;
1290         }
1291 
1292         spin_lock(&fs_info->qgroup_lock);
1293         ret = add_relation_rb(fs_info, src, dst);
1294         if (ret < 0) {
1295                 spin_unlock(&fs_info->qgroup_lock);
1296                 goto out;
1297         }
1298         ret = quick_update_accounting(fs_info, tmp, src, dst, 1);
1299         spin_unlock(&fs_info->qgroup_lock);
1300 out:
1301         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1302         ulist_free(tmp);
1303         return ret;
1304 }
1305 
1306 static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1307                                  u64 dst)
1308 {
1309         struct btrfs_fs_info *fs_info = trans->fs_info;
1310         struct btrfs_root *quota_root;
1311         struct btrfs_qgroup *parent;
1312         struct btrfs_qgroup *member;
1313         struct btrfs_qgroup_list *list;
1314         struct ulist *tmp;
1315         int ret = 0;
1316         int err;
1317 
1318         tmp = ulist_alloc(GFP_KERNEL);
1319         if (!tmp)
1320                 return -ENOMEM;
1321 
1322         quota_root = fs_info->quota_root;
1323         if (!quota_root) {
1324                 ret = -EINVAL;
1325                 goto out;
1326         }
1327 
1328         member = find_qgroup_rb(fs_info, src);
1329         parent = find_qgroup_rb(fs_info, dst);
1330         if (!member || !parent) {
1331                 ret = -EINVAL;
1332                 goto out;
1333         }
1334 
1335         /* check if such qgroup relation exist firstly */
1336         list_for_each_entry(list, &member->groups, next_group) {
1337                 if (list->group == parent)
1338                         goto exist;
1339         }
1340         ret = -ENOENT;
1341         goto out;
1342 exist:
1343         ret = del_qgroup_relation_item(trans, src, dst);
1344         err = del_qgroup_relation_item(trans, dst, src);
1345         if (err && !ret)
1346                 ret = err;
1347 
1348         spin_lock(&fs_info->qgroup_lock);
1349         del_relation_rb(fs_info, src, dst);
1350         ret = quick_update_accounting(fs_info, tmp, src, dst, -1);
1351         spin_unlock(&fs_info->qgroup_lock);
1352 out:
1353         ulist_free(tmp);
1354         return ret;
1355 }
1356 
1357 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1358                               u64 dst)
1359 {
1360         struct btrfs_fs_info *fs_info = trans->fs_info;
1361         int ret = 0;
1362 
1363         mutex_lock(&fs_info->qgroup_ioctl_lock);
1364         ret = __del_qgroup_relation(trans, src, dst);
1365         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1366 
1367         return ret;
1368 }
1369 
1370 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1371 {
1372         struct btrfs_fs_info *fs_info = trans->fs_info;
1373         struct btrfs_root *quota_root;
1374         struct btrfs_qgroup *qgroup;
1375         int ret = 0;
1376 
1377         mutex_lock(&fs_info->qgroup_ioctl_lock);
1378         quota_root = fs_info->quota_root;
1379         if (!quota_root) {
1380                 ret = -EINVAL;
1381                 goto out;
1382         }
1383         qgroup = find_qgroup_rb(fs_info, qgroupid);
1384         if (qgroup) {
1385                 ret = -EEXIST;
1386                 goto out;
1387         }
1388 
1389         ret = add_qgroup_item(trans, quota_root, qgroupid);
1390         if (ret)
1391                 goto out;
1392 
1393         spin_lock(&fs_info->qgroup_lock);
1394         qgroup = add_qgroup_rb(fs_info, qgroupid);
1395         spin_unlock(&fs_info->qgroup_lock);
1396 
1397         if (IS_ERR(qgroup))
1398                 ret = PTR_ERR(qgroup);
1399 out:
1400         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1401         return ret;
1402 }
1403 
1404 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1405 {
1406         struct btrfs_fs_info *fs_info = trans->fs_info;
1407         struct btrfs_root *quota_root;
1408         struct btrfs_qgroup *qgroup;
1409         struct btrfs_qgroup_list *list;
1410         int ret = 0;
1411 
1412         mutex_lock(&fs_info->qgroup_ioctl_lock);
1413         quota_root = fs_info->quota_root;
1414         if (!quota_root) {
1415                 ret = -EINVAL;
1416                 goto out;
1417         }
1418 
1419         qgroup = find_qgroup_rb(fs_info, qgroupid);
1420         if (!qgroup) {
1421                 ret = -ENOENT;
1422                 goto out;
1423         }
1424 
1425         /* Check if there are no children of this qgroup */
1426         if (!list_empty(&qgroup->members)) {
1427                 ret = -EBUSY;
1428                 goto out;
1429         }
1430 
1431         ret = del_qgroup_item(trans, qgroupid);
1432         if (ret && ret != -ENOENT)
1433                 goto out;
1434 
1435         while (!list_empty(&qgroup->groups)) {
1436                 list = list_first_entry(&qgroup->groups,
1437                                         struct btrfs_qgroup_list, next_group);
1438                 ret = __del_qgroup_relation(trans, qgroupid,
1439                                             list->group->qgroupid);
1440                 if (ret)
1441                         goto out;
1442         }
1443 
1444         spin_lock(&fs_info->qgroup_lock);
1445         del_qgroup_rb(fs_info, qgroupid);
1446         spin_unlock(&fs_info->qgroup_lock);
1447 out:
1448         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1449         return ret;
1450 }
1451 
1452 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
1453                        struct btrfs_qgroup_limit *limit)
1454 {
1455         struct btrfs_fs_info *fs_info = trans->fs_info;
1456         struct btrfs_root *quota_root;
1457         struct btrfs_qgroup *qgroup;
1458         int ret = 0;
1459         /* Sometimes we would want to clear the limit on this qgroup.
1460          * To meet this requirement, we treat the -1 as a special value
1461          * which tell kernel to clear the limit on this qgroup.
1462          */
1463         const u64 CLEAR_VALUE = -1;
1464 
1465         mutex_lock(&fs_info->qgroup_ioctl_lock);
1466         quota_root = fs_info->quota_root;
1467         if (!quota_root) {
1468                 ret = -EINVAL;
1469                 goto out;
1470         }
1471 
1472         qgroup = find_qgroup_rb(fs_info, qgroupid);
1473         if (!qgroup) {
1474                 ret = -ENOENT;
1475                 goto out;
1476         }
1477 
1478         spin_lock(&fs_info->qgroup_lock);
1479         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_RFER) {
1480                 if (limit->max_rfer == CLEAR_VALUE) {
1481                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1482                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1483                         qgroup->max_rfer = 0;
1484                 } else {
1485                         qgroup->max_rfer = limit->max_rfer;
1486                 }
1487         }
1488         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
1489                 if (limit->max_excl == CLEAR_VALUE) {
1490                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1491                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1492                         qgroup->max_excl = 0;
1493                 } else {
1494                         qgroup->max_excl = limit->max_excl;
1495                 }
1496         }
1497         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_RFER) {
1498                 if (limit->rsv_rfer == CLEAR_VALUE) {
1499                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1500                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1501                         qgroup->rsv_rfer = 0;
1502                 } else {
1503                         qgroup->rsv_rfer = limit->rsv_rfer;
1504                 }
1505         }
1506         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_EXCL) {
1507                 if (limit->rsv_excl == CLEAR_VALUE) {
1508                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1509                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1510                         qgroup->rsv_excl = 0;
1511                 } else {
1512                         qgroup->rsv_excl = limit->rsv_excl;
1513                 }
1514         }
1515         qgroup->lim_flags |= limit->flags;
1516 
1517         spin_unlock(&fs_info->qgroup_lock);
1518 
1519         ret = update_qgroup_limit_item(trans, qgroup);
1520         if (ret) {
1521                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1522                 btrfs_info(fs_info, "unable to update quota limit for %llu",
1523                        qgroupid);
1524         }
1525 
1526 out:
1527         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1528         return ret;
1529 }
1530 
1531 int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
1532                                 struct btrfs_delayed_ref_root *delayed_refs,
1533                                 struct btrfs_qgroup_extent_record *record)
1534 {
1535         struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
1536         struct rb_node *parent_node = NULL;
1537         struct btrfs_qgroup_extent_record *entry;
1538         u64 bytenr = record->bytenr;
1539 
1540         lockdep_assert_held(&delayed_refs->lock);
1541         trace_btrfs_qgroup_trace_extent(fs_info, record);
1542 
1543         while (*p) {
1544                 parent_node = *p;
1545                 entry = rb_entry(parent_node, struct btrfs_qgroup_extent_record,
1546                                  node);
1547                 if (bytenr < entry->bytenr) {
1548                         p = &(*p)->rb_left;
1549                 } else if (bytenr > entry->bytenr) {
1550                         p = &(*p)->rb_right;
1551                 } else {
1552                         if (record->data_rsv && !entry->data_rsv) {
1553                                 entry->data_rsv = record->data_rsv;
1554                                 entry->data_rsv_refroot =
1555                                         record->data_rsv_refroot;
1556                         }
1557                         return 1;
1558                 }
1559         }
1560 
1561         rb_link_node(&record->node, parent_node, p);
1562         rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
1563         return 0;
1564 }
1565 
1566 int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
1567                                    struct btrfs_qgroup_extent_record *qrecord)
1568 {
1569         struct ulist *old_root;
1570         u64 bytenr = qrecord->bytenr;
1571         int ret;
1572 
1573         ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false);
1574         if (ret < 0) {
1575                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1576                 btrfs_warn(fs_info,
1577 "error accounting new delayed refs extent (err code: %d), quota inconsistent",
1578                         ret);
1579                 return 0;
1580         }
1581 
1582         /*
1583          * Here we don't need to get the lock of
1584          * trans->transaction->delayed_refs, since inserted qrecord won't
1585          * be deleted, only qrecord->node may be modified (new qrecord insert)
1586          *
1587          * So modifying qrecord->old_roots is safe here
1588          */
1589         qrecord->old_roots = old_root;
1590         return 0;
1591 }
1592 
1593 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
1594                               u64 num_bytes, gfp_t gfp_flag)
1595 {
1596         struct btrfs_fs_info *fs_info = trans->fs_info;
1597         struct btrfs_qgroup_extent_record *record;
1598         struct btrfs_delayed_ref_root *delayed_refs;
1599         int ret;
1600 
1601         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)
1602             || bytenr == 0 || num_bytes == 0)
1603                 return 0;
1604         record = kzalloc(sizeof(*record), gfp_flag);
1605         if (!record)
1606                 return -ENOMEM;
1607 
1608         delayed_refs = &trans->transaction->delayed_refs;
1609         record->bytenr = bytenr;
1610         record->num_bytes = num_bytes;
1611         record->old_roots = NULL;
1612 
1613         spin_lock(&delayed_refs->lock);
1614         ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record);
1615         spin_unlock(&delayed_refs->lock);
1616         if (ret > 0) {
1617                 kfree(record);
1618                 return 0;
1619         }
1620         return btrfs_qgroup_trace_extent_post(fs_info, record);
1621 }
1622 
1623 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
1624                                   struct extent_buffer *eb)
1625 {
1626         struct btrfs_fs_info *fs_info = trans->fs_info;
1627         int nr = btrfs_header_nritems(eb);
1628         int i, extent_type, ret;
1629         struct btrfs_key key;
1630         struct btrfs_file_extent_item *fi;
1631         u64 bytenr, num_bytes;
1632 
1633         /* We can be called directly from walk_up_proc() */
1634         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1635                 return 0;
1636 
1637         for (i = 0; i < nr; i++) {
1638                 btrfs_item_key_to_cpu(eb, &key, i);
1639 
1640                 if (key.type != BTRFS_EXTENT_DATA_KEY)
1641                         continue;
1642 
1643                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
1644                 /* filter out non qgroup-accountable extents  */
1645                 extent_type = btrfs_file_extent_type(eb, fi);
1646 
1647                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
1648                         continue;
1649 
1650                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
1651                 if (!bytenr)
1652                         continue;
1653 
1654                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
1655 
1656                 ret = btrfs_qgroup_trace_extent(trans, bytenr, num_bytes,
1657                                                 GFP_NOFS);
1658                 if (ret)
1659                         return ret;
1660         }
1661         cond_resched();
1662         return 0;
1663 }
1664 
1665 /*
1666  * Walk up the tree from the bottom, freeing leaves and any interior
1667  * nodes which have had all slots visited. If a node (leaf or
1668  * interior) is freed, the node above it will have it's slot
1669  * incremented. The root node will never be freed.
1670  *
1671  * At the end of this function, we should have a path which has all
1672  * slots incremented to the next position for a search. If we need to
1673  * read a new node it will be NULL and the node above it will have the
1674  * correct slot selected for a later read.
1675  *
1676  * If we increment the root nodes slot counter past the number of
1677  * elements, 1 is returned to signal completion of the search.
1678  */
1679 static int adjust_slots_upwards(struct btrfs_path *path, int root_level)
1680 {
1681         int level = 0;
1682         int nr, slot;
1683         struct extent_buffer *eb;
1684 
1685         if (root_level == 0)
1686                 return 1;
1687 
1688         while (level <= root_level) {
1689                 eb = path->nodes[level];
1690                 nr = btrfs_header_nritems(eb);
1691                 path->slots[level]++;
1692                 slot = path->slots[level];
1693                 if (slot >= nr || level == 0) {
1694                         /*
1695                          * Don't free the root -  we will detect this
1696                          * condition after our loop and return a
1697                          * positive value for caller to stop walking the tree.
1698                          */
1699                         if (level != root_level) {
1700                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
1701                                 path->locks[level] = 0;
1702 
1703                                 free_extent_buffer(eb);
1704                                 path->nodes[level] = NULL;
1705                                 path->slots[level] = 0;
1706                         }
1707                 } else {
1708                         /*
1709                          * We have a valid slot to walk back down
1710                          * from. Stop here so caller can process these
1711                          * new nodes.
1712                          */
1713                         break;
1714                 }
1715 
1716                 level++;
1717         }
1718 
1719         eb = path->nodes[root_level];
1720         if (path->slots[root_level] >= btrfs_header_nritems(eb))
1721                 return 1;
1722 
1723         return 0;
1724 }
1725 
1726 /*
1727  * Helper function to trace a subtree tree block swap.
1728  *
1729  * The swap will happen in highest tree block, but there may be a lot of
1730  * tree blocks involved.
1731  *
1732  * For example:
1733  *  OO = Old tree blocks
1734  *  NN = New tree blocks allocated during balance
1735  *
1736  *           File tree (257)                  Reloc tree for 257
1737  * L2              OO                                NN
1738  *               /    \                            /    \
1739  * L1          OO      OO (a)                    OO      NN (a)
1740  *            / \     / \                       / \     / \
1741  * L0       OO   OO OO   OO                   OO   OO NN   NN
1742  *                  (b)  (c)                          (b)  (c)
1743  *
1744  * When calling qgroup_trace_extent_swap(), we will pass:
1745  * @src_eb = OO(a)
1746  * @dst_path = [ nodes[1] = NN(a), nodes[0] = NN(c) ]
1747  * @dst_level = 0
1748  * @root_level = 1
1749  *
1750  * In that case, qgroup_trace_extent_swap() will search from OO(a) to
1751  * reach OO(c), then mark both OO(c) and NN(c) as qgroup dirty.
1752  *
1753  * The main work of qgroup_trace_extent_swap() can be split into 3 parts:
1754  *
1755  * 1) Tree search from @src_eb
1756  *    It should acts as a simplified btrfs_search_slot().
1757  *    The key for search can be extracted from @dst_path->nodes[dst_level]
1758  *    (first key).
1759  *
1760  * 2) Mark the final tree blocks in @src_path and @dst_path qgroup dirty
1761  *    NOTE: In above case, OO(a) and NN(a) won't be marked qgroup dirty.
1762  *    They should be marked during previous (@dst_level = 1) iteration.
1763  *
1764  * 3) Mark file extents in leaves dirty
1765  *    We don't have good way to pick out new file extents only.
1766  *    So we still follow the old method by scanning all file extents in
1767  *    the leave.
1768  *
1769  * This function can free us from keeping two paths, thus later we only need
1770  * to care about how to iterate all new tree blocks in reloc tree.
1771  */
1772 static int qgroup_trace_extent_swap(struct btrfs_trans_handle* trans,
1773                                     struct extent_buffer *src_eb,
1774                                     struct btrfs_path *dst_path,
1775                                     int dst_level, int root_level,
1776                                     bool trace_leaf)
1777 {
1778         struct btrfs_key key;
1779         struct btrfs_path *src_path;
1780         struct btrfs_fs_info *fs_info = trans->fs_info;
1781         u32 nodesize = fs_info->nodesize;
1782         int cur_level = root_level;
1783         int ret;
1784 
1785         BUG_ON(dst_level > root_level);
1786         /* Level mismatch */
1787         if (btrfs_header_level(src_eb) != root_level)
1788                 return -EINVAL;
1789 
1790         src_path = btrfs_alloc_path();
1791         if (!src_path) {
1792                 ret = -ENOMEM;
1793                 goto out;
1794         }
1795 
1796         if (dst_level)
1797                 btrfs_node_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
1798         else
1799                 btrfs_item_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
1800 
1801         /* For src_path */
1802         extent_buffer_get(src_eb);
1803         src_path->nodes[root_level] = src_eb;
1804         src_path->slots[root_level] = dst_path->slots[root_level];
1805         src_path->locks[root_level] = 0;
1806 
1807         /* A simplified version of btrfs_search_slot() */
1808         while (cur_level >= dst_level) {
1809                 struct btrfs_key src_key;
1810                 struct btrfs_key dst_key;
1811 
1812                 if (src_path->nodes[cur_level] == NULL) {
1813                         struct btrfs_key first_key;
1814                         struct extent_buffer *eb;
1815                         int parent_slot;
1816                         u64 child_gen;
1817                         u64 child_bytenr;
1818 
1819                         eb = src_path->nodes[cur_level + 1];
1820                         parent_slot = src_path->slots[cur_level + 1];
1821                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
1822                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
1823                         btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
1824 
1825                         eb = read_tree_block(fs_info, child_bytenr, child_gen,
1826                                              cur_level, &first_key);
1827                         if (IS_ERR(eb)) {
1828                                 ret = PTR_ERR(eb);
1829                                 goto out;
1830                         } else if (!extent_buffer_uptodate(eb)) {
1831                                 free_extent_buffer(eb);
1832                                 ret = -EIO;
1833                                 goto out;
1834                         }
1835 
1836                         src_path->nodes[cur_level] = eb;
1837 
1838                         btrfs_tree_read_lock(eb);
1839                         btrfs_set_lock_blocking_read(eb);
1840                         src_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
1841                 }
1842 
1843                 src_path->slots[cur_level] = dst_path->slots[cur_level];
1844                 if (cur_level) {
1845                         btrfs_node_key_to_cpu(dst_path->nodes[cur_level],
1846                                         &dst_key, dst_path->slots[cur_level]);
1847                         btrfs_node_key_to_cpu(src_path->nodes[cur_level],
1848                                         &src_key, src_path->slots[cur_level]);
1849                 } else {
1850                         btrfs_item_key_to_cpu(dst_path->nodes[cur_level],
1851                                         &dst_key, dst_path->slots[cur_level]);
1852                         btrfs_item_key_to_cpu(src_path->nodes[cur_level],
1853                                         &src_key, src_path->slots[cur_level]);
1854                 }
1855                 /* Content mismatch, something went wrong */
1856                 if (btrfs_comp_cpu_keys(&dst_key, &src_key)) {
1857                         ret = -ENOENT;
1858                         goto out;
1859                 }
1860                 cur_level--;
1861         }
1862 
1863         /*
1864          * Now both @dst_path and @src_path have been populated, record the tree
1865          * blocks for qgroup accounting.
1866          */
1867         ret = btrfs_qgroup_trace_extent(trans, src_path->nodes[dst_level]->start,
1868                         nodesize, GFP_NOFS);
1869         if (ret < 0)
1870                 goto out;
1871         ret = btrfs_qgroup_trace_extent(trans,
1872                         dst_path->nodes[dst_level]->start,
1873                         nodesize, GFP_NOFS);
1874         if (ret < 0)
1875                 goto out;
1876 
1877         /* Record leaf file extents */
1878         if (dst_level == 0 && trace_leaf) {
1879                 ret = btrfs_qgroup_trace_leaf_items(trans, src_path->nodes[0]);
1880                 if (ret < 0)
1881                         goto out;
1882                 ret = btrfs_qgroup_trace_leaf_items(trans, dst_path->nodes[0]);
1883         }
1884 out:
1885         btrfs_free_path(src_path);
1886         return ret;
1887 }
1888 
1889 /*
1890  * Helper function to do recursive generation-aware depth-first search, to
1891  * locate all new tree blocks in a subtree of reloc tree.
1892  *
1893  * E.g. (OO = Old tree blocks, NN = New tree blocks, whose gen == last_snapshot)
1894  *         reloc tree
1895  * L2         NN (a)
1896  *          /    \
1897  * L1    OO        NN (b)
1898  *      /  \      /  \
1899  * L0  OO  OO    OO  NN
1900  *               (c) (d)
1901  * If we pass:
1902  * @dst_path = [ nodes[1] = NN(b), nodes[0] = NULL ],
1903  * @cur_level = 1
1904  * @root_level = 1
1905  *
1906  * We will iterate through tree blocks NN(b), NN(d) and info qgroup to trace
1907  * above tree blocks along with their counter parts in file tree.
1908  * While during search, old tree blocks OO(c) will be skipped as tree block swap
1909  * won't affect OO(c).
1910  */
1911 static int qgroup_trace_new_subtree_blocks(struct btrfs_trans_handle* trans,
1912                                            struct extent_buffer *src_eb,
1913                                            struct btrfs_path *dst_path,
1914                                            int cur_level, int root_level,
1915                                            u64 last_snapshot, bool trace_leaf)
1916 {
1917         struct btrfs_fs_info *fs_info = trans->fs_info;
1918         struct extent_buffer *eb;
1919         bool need_cleanup = false;
1920         int ret = 0;
1921         int i;
1922 
1923         /* Level sanity check */
1924         if (cur_level < 0 || cur_level >= BTRFS_MAX_LEVEL - 1 ||
1925             root_level < 0 || root_level >= BTRFS_MAX_LEVEL - 1 ||
1926             root_level < cur_level) {
1927                 btrfs_err_rl(fs_info,
1928                         "%s: bad levels, cur_level=%d root_level=%d",
1929                         __func__, cur_level, root_level);
1930                 return -EUCLEAN;
1931         }
1932 
1933         /* Read the tree block if needed */
1934         if (dst_path->nodes[cur_level] == NULL) {
1935                 struct btrfs_key first_key;
1936                 int parent_slot;
1937                 u64 child_gen;
1938                 u64 child_bytenr;
1939 
1940                 /*
1941                  * dst_path->nodes[root_level] must be initialized before
1942                  * calling this function.
1943                  */
1944                 if (cur_level == root_level) {
1945                         btrfs_err_rl(fs_info,
1946         "%s: dst_path->nodes[%d] not initialized, root_level=%d cur_level=%d",
1947                                 __func__, root_level, root_level, cur_level);
1948                         return -EUCLEAN;
1949                 }
1950 
1951                 /*
1952                  * We need to get child blockptr/gen from parent before we can
1953                  * read it.
1954                   */
1955                 eb = dst_path->nodes[cur_level + 1];
1956                 parent_slot = dst_path->slots[cur_level + 1];
1957                 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
1958                 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
1959                 btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
1960 
1961                 /* This node is old, no need to trace */
1962                 if (child_gen < last_snapshot)
1963                         goto out;
1964 
1965                 eb = read_tree_block(fs_info, child_bytenr, child_gen,
1966                                      cur_level, &first_key);
1967                 if (IS_ERR(eb)) {
1968                         ret = PTR_ERR(eb);
1969                         goto out;
1970                 } else if (!extent_buffer_uptodate(eb)) {
1971                         free_extent_buffer(eb);
1972                         ret = -EIO;
1973                         goto out;
1974                 }
1975 
1976                 dst_path->nodes[cur_level] = eb;
1977                 dst_path->slots[cur_level] = 0;
1978 
1979                 btrfs_tree_read_lock(eb);
1980                 btrfs_set_lock_blocking_read(eb);
1981                 dst_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
1982                 need_cleanup = true;
1983         }
1984 
1985         /* Now record this tree block and its counter part for qgroups */
1986         ret = qgroup_trace_extent_swap(trans, src_eb, dst_path, cur_level,
1987                                        root_level, trace_leaf);
1988         if (ret < 0)
1989                 goto cleanup;
1990 
1991         eb = dst_path->nodes[cur_level];
1992 
1993         if (cur_level > 0) {
1994                 /* Iterate all child tree blocks */
1995                 for (i = 0; i < btrfs_header_nritems(eb); i++) {
1996                         /* Skip old tree blocks as they won't be swapped */
1997                         if (btrfs_node_ptr_generation(eb, i) < last_snapshot)
1998                                 continue;
1999                         dst_path->slots[cur_level] = i;
2000 
2001                         /* Recursive call (at most 7 times) */
2002                         ret = qgroup_trace_new_subtree_blocks(trans, src_eb,
2003                                         dst_path, cur_level - 1, root_level,
2004                                         last_snapshot, trace_leaf);
2005                         if (ret < 0)
2006                                 goto cleanup;
2007                 }
2008         }
2009 
2010 cleanup:
2011         if (need_cleanup) {
2012                 /* Clean up */
2013                 btrfs_tree_unlock_rw(dst_path->nodes[cur_level],
2014                                      dst_path->locks[cur_level]);
2015                 free_extent_buffer(dst_path->nodes[cur_level]);
2016                 dst_path->nodes[cur_level] = NULL;
2017                 dst_path->slots[cur_level] = 0;
2018                 dst_path->locks[cur_level] = 0;
2019         }
2020 out:
2021         return ret;
2022 }
2023 
2024 static int qgroup_trace_subtree_swap(struct btrfs_trans_handle *trans,
2025                                 struct extent_buffer *src_eb,
2026                                 struct extent_buffer *dst_eb,
2027                                 u64 last_snapshot, bool trace_leaf)
2028 {
2029         struct btrfs_fs_info *fs_info = trans->fs_info;
2030         struct btrfs_path *dst_path = NULL;
2031         int level;
2032         int ret;
2033 
2034         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2035                 return 0;
2036 
2037         /* Wrong parameter order */
2038         if (btrfs_header_generation(src_eb) > btrfs_header_generation(dst_eb)) {
2039                 btrfs_err_rl(fs_info,
2040                 "%s: bad parameter order, src_gen=%llu dst_gen=%llu", __func__,
2041                              btrfs_header_generation(src_eb),
2042                              btrfs_header_generation(dst_eb));
2043                 return -EUCLEAN;
2044         }
2045 
2046         if (!extent_buffer_uptodate(src_eb) || !extent_buffer_uptodate(dst_eb)) {
2047                 ret = -EIO;
2048                 goto out;
2049         }
2050 
2051         level = btrfs_header_level(dst_eb);
2052         dst_path = btrfs_alloc_path();
2053         if (!dst_path) {
2054                 ret = -ENOMEM;
2055                 goto out;
2056         }
2057         /* For dst_path */
2058         extent_buffer_get(dst_eb);
2059         dst_path->nodes[level] = dst_eb;
2060         dst_path->slots[level] = 0;
2061         dst_path->locks[level] = 0;
2062 
2063         /* Do the generation aware breadth-first search */
2064         ret = qgroup_trace_new_subtree_blocks(trans, src_eb, dst_path, level,
2065                                               level, last_snapshot, trace_leaf);
2066         if (ret < 0)
2067                 goto out;
2068         ret = 0;
2069 
2070 out:
2071         btrfs_free_path(dst_path);
2072         if (ret < 0)
2073                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2074         return ret;
2075 }
2076 
2077 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
2078                                struct extent_buffer *root_eb,
2079                                u64 root_gen, int root_level)
2080 {
2081         struct btrfs_fs_info *fs_info = trans->fs_info;
2082         int ret = 0;
2083         int level;
2084         struct extent_buffer *eb = root_eb;
2085         struct btrfs_path *path = NULL;
2086 
2087         BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
2088         BUG_ON(root_eb == NULL);
2089 
2090         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2091                 return 0;
2092 
2093         if (!extent_buffer_uptodate(root_eb)) {
2094                 ret = btrfs_read_buffer(root_eb, root_gen, root_level, NULL);
2095                 if (ret)
2096                         goto out;
2097         }
2098 
2099         if (root_level == 0) {
2100                 ret = btrfs_qgroup_trace_leaf_items(trans, root_eb);
2101                 goto out;
2102         }
2103 
2104         path = btrfs_alloc_path();
2105         if (!path)
2106                 return -ENOMEM;
2107 
2108         /*
2109          * Walk down the tree.  Missing extent blocks are filled in as
2110          * we go. Metadata is accounted every time we read a new
2111          * extent block.
2112          *
2113          * When we reach a leaf, we account for file extent items in it,
2114          * walk back up the tree (adjusting slot pointers as we go)
2115          * and restart the search process.
2116          */
2117         extent_buffer_get(root_eb); /* For path */
2118         path->nodes[root_level] = root_eb;
2119         path->slots[root_level] = 0;
2120         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
2121 walk_down:
2122         level = root_level;
2123         while (level >= 0) {
2124                 if (path->nodes[level] == NULL) {
2125                         struct btrfs_key first_key;
2126                         int parent_slot;
2127                         u64 child_gen;
2128                         u64 child_bytenr;
2129 
2130                         /*
2131                          * We need to get child blockptr/gen from parent before
2132                          * we can read it.
2133                           */
2134                         eb = path->nodes[level + 1];
2135                         parent_slot = path->slots[level + 1];
2136                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
2137                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
2138                         btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
2139 
2140                         eb = read_tree_block(fs_info, child_bytenr, child_gen,
2141                                              level, &first_key);
2142                         if (IS_ERR(eb)) {
2143                                 ret = PTR_ERR(eb);
2144                                 goto out;
2145                         } else if (!extent_buffer_uptodate(eb)) {
2146                                 free_extent_buffer(eb);
2147                                 ret = -EIO;
2148                                 goto out;
2149                         }
2150 
2151                         path->nodes[level] = eb;
2152                         path->slots[level] = 0;
2153 
2154                         btrfs_tree_read_lock(eb);
2155                         btrfs_set_lock_blocking_read(eb);
2156                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
2157 
2158                         ret = btrfs_qgroup_trace_extent(trans, child_bytenr,
2159                                                         fs_info->nodesize,
2160                                                         GFP_NOFS);
2161                         if (ret)
2162                                 goto out;
2163                 }
2164 
2165                 if (level == 0) {
2166                         ret = btrfs_qgroup_trace_leaf_items(trans,
2167                                                             path->nodes[level]);
2168                         if (ret)
2169                                 goto out;
2170 
2171                         /* Nonzero return here means we completed our search */
2172                         ret = adjust_slots_upwards(path, root_level);
2173                         if (ret)
2174                                 break;
2175 
2176                         /* Restart search with new slots */
2177                         goto walk_down;
2178                 }
2179 
2180                 level--;
2181         }
2182 
2183         ret = 0;
2184 out:
2185         btrfs_free_path(path);
2186 
2187         return ret;
2188 }
2189 
2190 #define UPDATE_NEW      0
2191 #define UPDATE_OLD      1
2192 /*
2193  * Walk all of the roots that points to the bytenr and adjust their refcnts.
2194  */
2195 static int qgroup_update_refcnt(struct btrfs_fs_info *fs_info,
2196                                 struct ulist *roots, struct ulist *tmp,
2197                                 struct ulist *qgroups, u64 seq, int update_old)
2198 {
2199         struct ulist_node *unode;
2200         struct ulist_iterator uiter;
2201         struct ulist_node *tmp_unode;
2202         struct ulist_iterator tmp_uiter;
2203         struct btrfs_qgroup *qg;
2204         int ret = 0;
2205 
2206         if (!roots)
2207                 return 0;
2208         ULIST_ITER_INIT(&uiter);
2209         while ((unode = ulist_next(roots, &uiter))) {
2210                 qg = find_qgroup_rb(fs_info, unode->val);
2211                 if (!qg)
2212                         continue;
2213 
2214                 ulist_reinit(tmp);
2215                 ret = ulist_add(qgroups, qg->qgroupid, qgroup_to_aux(qg),
2216                                 GFP_ATOMIC);
2217                 if (ret < 0)
2218                         return ret;
2219                 ret = ulist_add(tmp, qg->qgroupid, qgroup_to_aux(qg), GFP_ATOMIC);
2220                 if (ret < 0)
2221                         return ret;
2222                 ULIST_ITER_INIT(&tmp_uiter);
2223                 while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
2224                         struct btrfs_qgroup_list *glist;
2225 
2226                         qg = unode_aux_to_qgroup(tmp_unode);
2227                         if (update_old)
2228                                 btrfs_qgroup_update_old_refcnt(qg, seq, 1);
2229                         else
2230                                 btrfs_qgroup_update_new_refcnt(qg, seq, 1);
2231                         list_for_each_entry(glist, &qg->groups, next_group) {
2232                                 ret = ulist_add(qgroups, glist->group->qgroupid,
2233                                                 qgroup_to_aux(glist->group),
2234                                                 GFP_ATOMIC);
2235                                 if (ret < 0)
2236                                         return ret;
2237                                 ret = ulist_add(tmp, glist->group->qgroupid,
2238                                                 qgroup_to_aux(glist->group),
2239                                                 GFP_ATOMIC);
2240                                 if (ret < 0)
2241                                         return ret;
2242                         }
2243                 }
2244         }
2245         return 0;
2246 }
2247 
2248 /*
2249  * Update qgroup rfer/excl counters.
2250  * Rfer update is easy, codes can explain themselves.
2251  *
2252  * Excl update is tricky, the update is split into 2 part.
2253  * Part 1: Possible exclusive <-> sharing detect:
2254  *      |       A       |       !A      |
2255  *  -------------------------------------
2256  *  B   |       *       |       -       |
2257  *  -------------------------------------
2258  *  !B  |       +       |       **      |
2259  *  -------------------------------------
2260  *
2261  * Conditions:
2262  * A:   cur_old_roots < nr_old_roots    (not exclusive before)
2263  * !A:  cur_old_roots == nr_old_roots   (possible exclusive before)
2264  * B:   cur_new_roots < nr_new_roots    (not exclusive now)
2265  * !B:  cur_new_roots == nr_new_roots   (possible exclusive now)
2266  *
2267  * Results:
2268  * +: Possible sharing -> exclusive     -: Possible exclusive -> sharing
2269  * *: Definitely not changed.           **: Possible unchanged.
2270  *
2271  * For !A and !B condition, the exception is cur_old/new_roots == 0 case.
2272  *
2273  * To make the logic clear, we first use condition A and B to split
2274  * combination into 4 results.
2275  *
2276  * Then, for result "+" and "-", check old/new_roots == 0 case, as in them
2277  * only on variant maybe 0.
2278  *
2279  * Lastly, check result **, since there are 2 variants maybe 0, split them
2280  * again(2x2).
2281  * But this time we don't need to consider other things, the codes and logic
2282  * is easy to understand now.
2283  */
2284 static int qgroup_update_counters(struct btrfs_fs_info *fs_info,
2285                                   struct ulist *qgroups,
2286                                   u64 nr_old_roots,
2287                                   u64 nr_new_roots,
2288                                   u64 num_bytes, u64 seq)
2289 {
2290         struct ulist_node *unode;
2291         struct ulist_iterator uiter;
2292         struct btrfs_qgroup *qg;
2293         u64 cur_new_count, cur_old_count;
2294 
2295         ULIST_ITER_INIT(&uiter);
2296         while ((unode = ulist_next(qgroups, &uiter))) {
2297                 bool dirty = false;
2298 
2299                 qg = unode_aux_to_qgroup(unode);
2300                 cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
2301                 cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
2302 
2303                 trace_qgroup_update_counters(fs_info, qg, cur_old_count,
2304                                              cur_new_count);
2305 
2306                 /* Rfer update part */
2307                 if (cur_old_count == 0 && cur_new_count > 0) {
2308                         qg->rfer += num_bytes;
2309                         qg->rfer_cmpr += num_bytes;
2310                         dirty = true;
2311                 }
2312                 if (cur_old_count > 0 && cur_new_count == 0) {
2313                         qg->rfer -= num_bytes;
2314                         qg->rfer_cmpr -= num_bytes;
2315                         dirty = true;
2316                 }
2317 
2318                 /* Excl update part */
2319                 /* Exclusive/none -> shared case */
2320                 if (cur_old_count == nr_old_roots &&
2321                     cur_new_count < nr_new_roots) {
2322                         /* Exclusive -> shared */
2323                         if (cur_old_count != 0) {
2324                                 qg->excl -= num_bytes;
2325                                 qg->excl_cmpr -= num_bytes;
2326                                 dirty = true;
2327                         }
2328                 }
2329 
2330                 /* Shared -> exclusive/none case */
2331                 if (cur_old_count < nr_old_roots &&
2332                     cur_new_count == nr_new_roots) {
2333                         /* Shared->exclusive */
2334                         if (cur_new_count != 0) {
2335                                 qg->excl += num_bytes;
2336                                 qg->excl_cmpr += num_bytes;
2337                                 dirty = true;
2338                         }
2339                 }
2340 
2341                 /* Exclusive/none -> exclusive/none case */
2342                 if (cur_old_count == nr_old_roots &&
2343                     cur_new_count == nr_new_roots) {
2344                         if (cur_old_count == 0) {
2345                                 /* None -> exclusive/none */
2346 
2347                                 if (cur_new_count != 0) {
2348                                         /* None -> exclusive */
2349                                         qg->excl += num_bytes;
2350                                         qg->excl_cmpr += num_bytes;
2351                                         dirty = true;
2352                                 }
2353                                 /* None -> none, nothing changed */
2354                         } else {
2355                                 /* Exclusive -> exclusive/none */
2356 
2357                                 if (cur_new_count == 0) {
2358                                         /* Exclusive -> none */
2359                                         qg->excl -= num_bytes;
2360                                         qg->excl_cmpr -= num_bytes;
2361                                         dirty = true;
2362                                 }
2363                                 /* Exclusive -> exclusive, nothing changed */
2364                         }
2365                 }
2366 
2367                 if (dirty)
2368                         qgroup_dirty(fs_info, qg);
2369         }
2370         return 0;
2371 }
2372 
2373 /*
2374  * Check if the @roots potentially is a list of fs tree roots
2375  *
2376  * Return 0 for definitely not a fs/subvol tree roots ulist
2377  * Return 1 for possible fs/subvol tree roots in the list (considering an empty
2378  *          one as well)
2379  */
2380 static int maybe_fs_roots(struct ulist *roots)
2381 {
2382         struct ulist_node *unode;
2383         struct ulist_iterator uiter;
2384 
2385         /* Empty one, still possible for fs roots */
2386         if (!roots || roots->nnodes == 0)
2387                 return 1;
2388 
2389         ULIST_ITER_INIT(&uiter);
2390         unode = ulist_next(roots, &uiter);
2391         if (!unode)
2392                 return 1;
2393 
2394         /*
2395          * If it contains fs tree roots, then it must belong to fs/subvol
2396          * trees.
2397          * If it contains a non-fs tree, it won't be shared with fs/subvol trees.
2398          */
2399         return is_fstree(unode->val);
2400 }
2401 
2402 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
2403                                 u64 num_bytes, struct ulist *old_roots,
2404                                 struct ulist *new_roots)
2405 {
2406         struct btrfs_fs_info *fs_info = trans->fs_info;
2407         struct ulist *qgroups = NULL;
2408         struct ulist *tmp = NULL;
2409         u64 seq;
2410         u64 nr_new_roots = 0;
2411         u64 nr_old_roots = 0;
2412         int ret = 0;
2413 
2414         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2415                 return 0;
2416 
2417         if (new_roots) {
2418                 if (!maybe_fs_roots(new_roots))
2419                         goto out_free;
2420                 nr_new_roots = new_roots->nnodes;
2421         }
2422         if (old_roots) {
2423                 if (!maybe_fs_roots(old_roots))
2424                         goto out_free;
2425                 nr_old_roots = old_roots->nnodes;
2426         }
2427 
2428         /* Quick exit, either not fs tree roots, or won't affect any qgroup */
2429         if (nr_old_roots == 0 && nr_new_roots == 0)
2430                 goto out_free;
2431 
2432         BUG_ON(!fs_info->quota_root);
2433 
2434         trace_btrfs_qgroup_account_extent(fs_info, trans->transid, bytenr,
2435                                         num_bytes, nr_old_roots, nr_new_roots);
2436 
2437         qgroups = ulist_alloc(GFP_NOFS);
2438         if (!qgroups) {
2439                 ret = -ENOMEM;
2440                 goto out_free;
2441         }
2442         tmp = ulist_alloc(GFP_NOFS);
2443         if (!tmp) {
2444                 ret = -ENOMEM;
2445                 goto out_free;
2446         }
2447 
2448         mutex_lock(&fs_info->qgroup_rescan_lock);
2449         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
2450                 if (fs_info->qgroup_rescan_progress.objectid <= bytenr) {
2451                         mutex_unlock(&fs_info->qgroup_rescan_lock);
2452                         ret = 0;
2453                         goto out_free;
2454                 }
2455         }
2456         mutex_unlock(&fs_info->qgroup_rescan_lock);
2457 
2458         spin_lock(&fs_info->qgroup_lock);
2459         seq = fs_info->qgroup_seq;
2460 
2461         /* Update old refcnts using old_roots */
2462         ret = qgroup_update_refcnt(fs_info, old_roots, tmp, qgroups, seq,
2463                                    UPDATE_OLD);
2464         if (ret < 0)
2465                 goto out;
2466 
2467         /* Update new refcnts using new_roots */
2468         ret = qgroup_update_refcnt(fs_info, new_roots, tmp, qgroups, seq,
2469                                    UPDATE_NEW);
2470         if (ret < 0)
2471                 goto out;
2472 
2473         qgroup_update_counters(fs_info, qgroups, nr_old_roots, nr_new_roots,
2474                                num_bytes, seq);
2475 
2476         /*
2477          * Bump qgroup_seq to avoid seq overlap
2478          */
2479         fs_info->qgroup_seq += max(nr_old_roots, nr_new_roots) + 1;
2480 out:
2481         spin_unlock(&fs_info->qgroup_lock);
2482 out_free:
2483         ulist_free(tmp);
2484         ulist_free(qgroups);
2485         ulist_free(old_roots);
2486         ulist_free(new_roots);
2487         return ret;
2488 }
2489 
2490 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
2491 {
2492         struct btrfs_fs_info *fs_info = trans->fs_info;
2493         struct btrfs_qgroup_extent_record *record;
2494         struct btrfs_delayed_ref_root *delayed_refs;
2495         struct ulist *new_roots = NULL;
2496         struct rb_node *node;
2497         u64 num_dirty_extents = 0;
2498         u64 qgroup_to_skip;
2499         int ret = 0;
2500 
2501         delayed_refs = &trans->transaction->delayed_refs;
2502         qgroup_to_skip = delayed_refs->qgroup_to_skip;
2503         while ((node = rb_first(&delayed_refs->dirty_extent_root))) {
2504                 record = rb_entry(node, struct btrfs_qgroup_extent_record,
2505                                   node);
2506 
2507                 num_dirty_extents++;
2508                 trace_btrfs_qgroup_account_extents(fs_info, record);
2509 
2510                 if (!ret) {
2511                         /*
2512                          * Old roots should be searched when inserting qgroup
2513                          * extent record
2514                          */
2515                         if (WARN_ON(!record->old_roots)) {
2516                                 /* Search commit root to find old_roots */
2517                                 ret = btrfs_find_all_roots(NULL, fs_info,
2518                                                 record->bytenr, 0,
2519                                                 &record->old_roots, false);
2520                                 if (ret < 0)
2521                                         goto cleanup;
2522                         }
2523 
2524                         /* Free the reserved data space */
2525                         btrfs_qgroup_free_refroot(fs_info,
2526                                         record->data_rsv_refroot,
2527                                         record->data_rsv,
2528                                         BTRFS_QGROUP_RSV_DATA);
2529                         /*
2530                          * Use SEQ_LAST as time_seq to do special search, which
2531                          * doesn't lock tree or delayed_refs and search current
2532                          * root. It's safe inside commit_transaction().
2533                          */
2534                         ret = btrfs_find_all_roots(trans, fs_info,
2535                                 record->bytenr, SEQ_LAST, &new_roots, false);
2536                         if (ret < 0)
2537                                 goto cleanup;
2538                         if (qgroup_to_skip) {
2539                                 ulist_del(new_roots, qgroup_to_skip, 0);
2540                                 ulist_del(record->old_roots, qgroup_to_skip,
2541                                           0);
2542                         }
2543                         ret = btrfs_qgroup_account_extent(trans, record->bytenr,
2544                                                           record->num_bytes,
2545                                                           record->old_roots,
2546                                                           new_roots);
2547                         record->old_roots = NULL;
2548                         new_roots = NULL;
2549                 }
2550 cleanup:
2551                 ulist_free(record->old_roots);
2552                 ulist_free(new_roots);
2553                 new_roots = NULL;
2554                 rb_erase(node, &delayed_refs->dirty_extent_root);
2555                 kfree(record);
2556 
2557         }
2558         trace_qgroup_num_dirty_extents(fs_info, trans->transid,
2559                                        num_dirty_extents);
2560         return ret;
2561 }
2562 
2563 /*
2564  * called from commit_transaction. Writes all changed qgroups to disk.
2565  */
2566 int btrfs_run_qgroups(struct btrfs_trans_handle *trans)
2567 {
2568         struct btrfs_fs_info *fs_info = trans->fs_info;
2569         struct btrfs_root *quota_root = fs_info->quota_root;
2570         int ret = 0;
2571 
2572         if (!quota_root)
2573                 return ret;
2574 
2575         spin_lock(&fs_info->qgroup_lock);
2576         while (!list_empty(&fs_info->dirty_qgroups)) {
2577                 struct btrfs_qgroup *qgroup;
2578                 qgroup = list_first_entry(&fs_info->dirty_qgroups,
2579                                           struct btrfs_qgroup, dirty);
2580                 list_del_init(&qgroup->dirty);
2581                 spin_unlock(&fs_info->qgroup_lock);
2582                 ret = update_qgroup_info_item(trans, qgroup);
2583                 if (ret)
2584                         fs_info->qgroup_flags |=
2585                                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2586                 ret = update_qgroup_limit_item(trans, qgroup);
2587                 if (ret)
2588                         fs_info->qgroup_flags |=
2589                                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2590                 spin_lock(&fs_info->qgroup_lock);
2591         }
2592         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2593                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_ON;
2594         else
2595                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
2596         spin_unlock(&fs_info->qgroup_lock);
2597 
2598         ret = update_qgroup_status_item(trans);
2599         if (ret)
2600                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2601 
2602         return ret;
2603 }
2604 
2605 /*
2606  * Copy the accounting information between qgroups. This is necessary
2607  * when a snapshot or a subvolume is created. Throwing an error will
2608  * cause a transaction abort so we take extra care here to only error
2609  * when a readonly fs is a reasonable outcome.
2610  */
2611 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
2612                          u64 objectid, struct btrfs_qgroup_inherit *inherit)
2613 {
2614         int ret = 0;
2615         int i;
2616         u64 *i_qgroups;
2617         bool committing = false;
2618         struct btrfs_fs_info *fs_info = trans->fs_info;
2619         struct btrfs_root *quota_root;
2620         struct btrfs_qgroup *srcgroup;
2621         struct btrfs_qgroup *dstgroup;
2622         u32 level_size = 0;
2623         u64 nums;
2624 
2625         /*
2626          * There are only two callers of this function.
2627          *
2628          * One in create_subvol() in the ioctl context, which needs to hold
2629          * the qgroup_ioctl_lock.
2630          *
2631          * The other one in create_pending_snapshot() where no other qgroup
2632          * code can modify the fs as they all need to either start a new trans
2633          * or hold a trans handler, thus we don't need to hold
2634          * qgroup_ioctl_lock.
2635          * This would avoid long and complex lock chain and make lockdep happy.
2636          */
2637         spin_lock(&fs_info->trans_lock);
2638         if (trans->transaction->state == TRANS_STATE_COMMIT_DOING)
2639                 committing = true;
2640         spin_unlock(&fs_info->trans_lock);
2641 
2642         if (!committing)
2643                 mutex_lock(&fs_info->qgroup_ioctl_lock);
2644         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2645                 goto out;
2646 
2647         quota_root = fs_info->quota_root;
2648         if (!quota_root) {
2649                 ret = -EINVAL;
2650                 goto out;
2651         }
2652 
2653         if (inherit) {
2654                 i_qgroups = (u64 *)(inherit + 1);
2655                 nums = inherit->num_qgroups + 2 * inherit->num_ref_copies +
2656                        2 * inherit->num_excl_copies;
2657                 for (i = 0; i < nums; ++i) {
2658                         srcgroup = find_qgroup_rb(fs_info, *i_qgroups);
2659 
2660                         /*
2661                          * Zero out invalid groups so we can ignore
2662                          * them later.
2663                          */
2664                         if (!srcgroup ||
2665                             ((srcgroup->qgroupid >> 48) <= (objectid >> 48)))
2666                                 *i_qgroups = 0ULL;
2667 
2668                         ++i_qgroups;
2669                 }
2670         }
2671 
2672         /*
2673          * create a tracking group for the subvol itself
2674          */
2675         ret = add_qgroup_item(trans, quota_root, objectid);
2676         if (ret)
2677                 goto out;
2678 
2679         /*
2680          * add qgroup to all inherited groups
2681          */
2682         if (inherit) {
2683                 i_qgroups = (u64 *)(inherit + 1);
2684                 for (i = 0; i < inherit->num_qgroups; ++i, ++i_qgroups) {
2685                         if (*i_qgroups == 0)
2686                                 continue;
2687                         ret = add_qgroup_relation_item(trans, objectid,
2688                                                        *i_qgroups);
2689                         if (ret && ret != -EEXIST)
2690                                 goto out;
2691                         ret = add_qgroup_relation_item(trans, *i_qgroups,
2692                                                        objectid);
2693                         if (ret && ret != -EEXIST)
2694                                 goto out;
2695                 }
2696                 ret = 0;
2697         }
2698 
2699 
2700         spin_lock(&fs_info->qgroup_lock);
2701 
2702         dstgroup = add_qgroup_rb(fs_info, objectid);
2703         if (IS_ERR(dstgroup)) {
2704                 ret = PTR_ERR(dstgroup);
2705                 goto unlock;
2706         }
2707 
2708         if (inherit && inherit->flags & BTRFS_QGROUP_INHERIT_SET_LIMITS) {
2709                 dstgroup->lim_flags = inherit->lim.flags;
2710                 dstgroup->max_rfer = inherit->lim.max_rfer;
2711                 dstgroup->max_excl = inherit->lim.max_excl;
2712                 dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
2713                 dstgroup->rsv_excl = inherit->lim.rsv_excl;
2714 
2715                 ret = update_qgroup_limit_item(trans, dstgroup);
2716                 if (ret) {
2717                         fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2718                         btrfs_info(fs_info,
2719                                    "unable to update quota limit for %llu",
2720                                    dstgroup->qgroupid);
2721                         goto unlock;
2722                 }
2723         }
2724 
2725         if (srcid) {
2726                 srcgroup = find_qgroup_rb(fs_info, srcid);
2727                 if (!srcgroup)
2728                         goto unlock;
2729 
2730                 /*
2731                  * We call inherit after we clone the root in order to make sure
2732                  * our counts don't go crazy, so at this point the only
2733                  * difference between the two roots should be the root node.
2734                  */
2735                 level_size = fs_info->nodesize;
2736                 dstgroup->rfer = srcgroup->rfer;
2737                 dstgroup->rfer_cmpr = srcgroup->rfer_cmpr;
2738                 dstgroup->excl = level_size;
2739                 dstgroup->excl_cmpr = level_size;
2740                 srcgroup->excl = level_size;
2741                 srcgroup->excl_cmpr = level_size;
2742 
2743                 /* inherit the limit info */
2744                 dstgroup->lim_flags = srcgroup->lim_flags;
2745                 dstgroup->max_rfer = srcgroup->max_rfer;
2746                 dstgroup->max_excl = srcgroup->max_excl;
2747                 dstgroup->rsv_rfer = srcgroup->rsv_rfer;
2748                 dstgroup->rsv_excl = srcgroup->rsv_excl;
2749 
2750                 qgroup_dirty(fs_info, dstgroup);
2751                 qgroup_dirty(fs_info, srcgroup);
2752         }
2753 
2754         if (!inherit)
2755                 goto unlock;
2756 
2757         i_qgroups = (u64 *)(inherit + 1);
2758         for (i = 0; i < inherit->num_qgroups; ++i) {
2759                 if (*i_qgroups) {
2760                         ret = add_relation_rb(fs_info, objectid, *i_qgroups);
2761                         if (ret)
2762                                 goto unlock;
2763                 }
2764                 ++i_qgroups;
2765         }
2766 
2767         for (i = 0; i <  inherit->num_ref_copies; ++i, i_qgroups += 2) {
2768                 struct btrfs_qgroup *src;
2769                 struct btrfs_qgroup *dst;
2770 
2771                 if (!i_qgroups[0] || !i_qgroups[1])
2772                         continue;
2773 
2774                 src = find_qgroup_rb(fs_info, i_qgroups[0]);
2775                 dst = find_qgroup_rb(fs_info, i_qgroups[1]);
2776 
2777                 if (!src || !dst) {
2778                         ret = -EINVAL;
2779                         goto unlock;
2780                 }
2781 
2782                 dst->rfer = src->rfer - level_size;
2783                 dst->rfer_cmpr = src->rfer_cmpr - level_size;
2784         }
2785         for (i = 0; i <  inherit->num_excl_copies; ++i, i_qgroups += 2) {
2786                 struct btrfs_qgroup *src;
2787                 struct btrfs_qgroup *dst;
2788 
2789                 if (!i_qgroups[0] || !i_qgroups[1])
2790                         continue;
2791 
2792                 src = find_qgroup_rb(fs_info, i_qgroups[0]);
2793                 dst = find_qgroup_rb(fs_info, i_qgroups[1]);
2794 
2795                 if (!src || !dst) {
2796                         ret = -EINVAL;
2797                         goto unlock;
2798                 }
2799 
2800                 dst->excl = src->excl + level_size;
2801                 dst->excl_cmpr = src->excl_cmpr + level_size;
2802         }
2803 
2804 unlock:
2805         spin_unlock(&fs_info->qgroup_lock);
2806 out:
2807         if (!committing)
2808                 mutex_unlock(&fs_info->qgroup_ioctl_lock);
2809         return ret;
2810 }
2811 
2812 /*
2813  * Two limits to commit transaction in advance.
2814  *
2815  * For RATIO, it will be 1/RATIO of the remaining limit as threshold.
2816  * For SIZE, it will be in byte unit as threshold.
2817  */
2818 #define QGROUP_FREE_RATIO               32
2819 #define QGROUP_FREE_SIZE                SZ_32M
2820 static bool qgroup_check_limits(struct btrfs_fs_info *fs_info,
2821                                 const struct btrfs_qgroup *qg, u64 num_bytes)
2822 {
2823         u64 free;
2824         u64 threshold;
2825 
2826         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
2827             qgroup_rsv_total(qg) + (s64)qg->rfer + num_bytes > qg->max_rfer)
2828                 return false;
2829 
2830         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
2831             qgroup_rsv_total(qg) + (s64)qg->excl + num_bytes > qg->max_excl)
2832                 return false;
2833 
2834         /*
2835          * Even if we passed the check, it's better to check if reservation
2836          * for meta_pertrans is pushing us near limit.
2837          * If there is too much pertrans reservation or it's near the limit,
2838          * let's try commit transaction to free some, using transaction_kthread
2839          */
2840         if ((qg->lim_flags & (BTRFS_QGROUP_LIMIT_MAX_RFER |
2841                               BTRFS_QGROUP_LIMIT_MAX_EXCL))) {
2842                 if (qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
2843                         free = qg->max_excl - qgroup_rsv_total(qg) - qg->excl;
2844                         threshold = min_t(u64, qg->max_excl / QGROUP_FREE_RATIO,
2845                                           QGROUP_FREE_SIZE);
2846                 } else {
2847                         free = qg->max_rfer - qgroup_rsv_total(qg) - qg->rfer;
2848                         threshold = min_t(u64, qg->max_rfer / QGROUP_FREE_RATIO,
2849                                           QGROUP_FREE_SIZE);
2850                 }
2851 
2852                 /*
2853                  * Use transaction_kthread to commit transaction, so we no
2854                  * longer need to bother nested transaction nor lock context.
2855                  */
2856                 if (free < threshold)
2857                         btrfs_commit_transaction_locksafe(fs_info);
2858         }
2859 
2860         return true;
2861 }
2862 
2863 static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce,
2864                           enum btrfs_qgroup_rsv_type type)
2865 {
2866         struct btrfs_root *quota_root;
2867         struct btrfs_qgroup *qgroup;
2868         struct btrfs_fs_info *fs_info = root->fs_info;
2869         u64 ref_root = root->root_key.objectid;
2870         int ret = 0;
2871         struct ulist_node *unode;
2872         struct ulist_iterator uiter;
2873 
2874         if (!is_fstree(ref_root))
2875                 return 0;
2876 
2877         if (num_bytes == 0)
2878                 return 0;
2879 
2880         if (test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags) &&
2881             capable(CAP_SYS_RESOURCE))
2882                 enforce = false;
2883 
2884         spin_lock(&fs_info->qgroup_lock);
2885         quota_root = fs_info->quota_root;
2886         if (!quota_root)
2887                 goto out;
2888 
2889         qgroup = find_qgroup_rb(fs_info, ref_root);
2890         if (!qgroup)
2891                 goto out;
2892 
2893         /*
2894          * in a first step, we check all affected qgroups if any limits would
2895          * be exceeded
2896          */
2897         ulist_reinit(fs_info->qgroup_ulist);
2898         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2899                         qgroup_to_aux(qgroup), GFP_ATOMIC);
2900         if (ret < 0)
2901                 goto out;
2902         ULIST_ITER_INIT(&uiter);
2903         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2904                 struct btrfs_qgroup *qg;
2905                 struct btrfs_qgroup_list *glist;
2906 
2907                 qg = unode_aux_to_qgroup(unode);
2908 
2909                 if (enforce && !qgroup_check_limits(fs_info, qg, num_bytes)) {
2910                         ret = -EDQUOT;
2911                         goto out;
2912                 }
2913 
2914                 list_for_each_entry(glist, &qg->groups, next_group) {
2915                         ret = ulist_add(fs_info->qgroup_ulist,
2916                                         glist->group->qgroupid,
2917                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
2918                         if (ret < 0)
2919                                 goto out;
2920                 }
2921         }
2922         ret = 0;
2923         /*
2924          * no limits exceeded, now record the reservation into all qgroups
2925          */
2926         ULIST_ITER_INIT(&uiter);
2927         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2928                 struct btrfs_qgroup *qg;
2929 
2930                 qg = unode_aux_to_qgroup(unode);
2931 
2932                 qgroup_rsv_add(fs_info, qg, num_bytes, type);
2933         }
2934 
2935 out:
2936         spin_unlock(&fs_info->qgroup_lock);
2937         return ret;
2938 }
2939 
2940 /*
2941  * Free @num_bytes of reserved space with @type for qgroup.  (Normally level 0
2942  * qgroup).
2943  *
2944  * Will handle all higher level qgroup too.
2945  *
2946  * NOTE: If @num_bytes is (u64)-1, this means to free all bytes of this qgroup.
2947  * This special case is only used for META_PERTRANS type.
2948  */
2949 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
2950                                u64 ref_root, u64 num_bytes,
2951                                enum btrfs_qgroup_rsv_type type)
2952 {
2953         struct btrfs_root *quota_root;
2954         struct btrfs_qgroup *qgroup;
2955         struct ulist_node *unode;
2956         struct ulist_iterator uiter;
2957         int ret = 0;
2958 
2959         if (!is_fstree(ref_root))
2960                 return;
2961 
2962         if (num_bytes == 0)
2963                 return;
2964 
2965         if (num_bytes == (u64)-1 && type != BTRFS_QGROUP_RSV_META_PERTRANS) {
2966                 WARN(1, "%s: Invalid type to free", __func__);
2967                 return;
2968         }
2969         spin_lock(&fs_info->qgroup_lock);
2970 
2971         quota_root = fs_info->quota_root;
2972         if (!quota_root)
2973                 goto out;
2974 
2975         qgroup = find_qgroup_rb(fs_info, ref_root);
2976         if (!qgroup)
2977                 goto out;
2978 
2979         if (num_bytes == (u64)-1)
2980                 /*
2981                  * We're freeing all pertrans rsv, get reserved value from
2982                  * level 0 qgroup as real num_bytes to free.
2983                  */
2984                 num_bytes = qgroup->rsv.values[type];
2985 
2986         ulist_reinit(fs_info->qgroup_ulist);
2987         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2988                         qgroup_to_aux(qgroup), GFP_ATOMIC);
2989         if (ret < 0)
2990                 goto out;
2991         ULIST_ITER_INIT(&uiter);
2992         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2993                 struct btrfs_qgroup *qg;
2994                 struct btrfs_qgroup_list *glist;
2995 
2996                 qg = unode_aux_to_qgroup(unode);
2997 
2998                 qgroup_rsv_release(fs_info, qg, num_bytes, type);
2999 
3000                 list_for_each_entry(glist, &qg->groups, next_group) {
3001                         ret = ulist_add(fs_info->qgroup_ulist,
3002                                         glist->group->qgroupid,
3003                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
3004                         if (ret < 0)
3005                                 goto out;
3006                 }
3007         }
3008 
3009 out:
3010         spin_unlock(&fs_info->qgroup_lock);
3011 }
3012 
3013 /*
3014  * Check if the leaf is the last leaf. Which means all node pointers
3015  * are at their last position.
3016  */
3017 static bool is_last_leaf(struct btrfs_path *path)
3018 {
3019         int i;
3020 
3021         for (i = 1; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
3022                 if (path->slots[i] != btrfs_header_nritems(path->nodes[i]) - 1)
3023                         return false;
3024         }
3025         return true;
3026 }
3027 
3028 /*
3029  * returns < 0 on error, 0 when more leafs are to be scanned.
3030  * returns 1 when done.
3031  */
3032 static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
3033                               struct btrfs_path *path)
3034 {
3035         struct btrfs_fs_info *fs_info = trans->fs_info;
3036         struct btrfs_key found;
3037         struct extent_buffer *scratch_leaf = NULL;
3038         struct ulist *roots = NULL;
3039         u64 num_bytes;
3040         bool done;
3041         int slot;
3042         int ret;
3043 
3044         mutex_lock(&fs_info->qgroup_rescan_lock);
3045         ret = btrfs_search_slot_for_read(fs_info->extent_root,
3046                                          &fs_info->qgroup_rescan_progress,
3047                                          path, 1, 0);
3048 
3049         btrfs_debug(fs_info,
3050                 "current progress key (%llu %u %llu), search_slot ret %d",
3051                 fs_info->qgroup_rescan_progress.objectid,
3052                 fs_info->qgroup_rescan_progress.type,
3053                 fs_info->qgroup_rescan_progress.offset, ret);
3054 
3055         if (ret) {
3056                 /*
3057                  * The rescan is about to end, we will not be scanning any
3058                  * further blocks. We cannot unset the RESCAN flag here, because
3059                  * we want to commit the transaction if everything went well.
3060                  * To make the live accounting work in this phase, we set our
3061                  * scan progress pointer such that every real extent objectid
3062                  * will be smaller.
3063                  */
3064                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3065                 btrfs_release_path(path);
3066                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3067                 return ret;
3068         }
3069         done = is_last_leaf(path);
3070 
3071         btrfs_item_key_to_cpu(path->nodes[0], &found,
3072                               btrfs_header_nritems(path->nodes[0]) - 1);
3073         fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
3074 
3075         scratch_leaf = btrfs_clone_extent_buffer(path->nodes[0]);
3076         if (!scratch_leaf) {
3077                 ret = -ENOMEM;
3078                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3079                 goto out;
3080         }
3081         slot = path->slots[0];
3082         btrfs_release_path(path);
3083         mutex_unlock(&fs_info->qgroup_rescan_lock);
3084 
3085         for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
3086                 btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
3087                 if (found.type != BTRFS_EXTENT_ITEM_KEY &&
3088                     found.type != BTRFS_METADATA_ITEM_KEY)
3089                         continue;
3090                 if (found.type == BTRFS_METADATA_ITEM_KEY)
3091                         num_bytes = fs_info->nodesize;
3092                 else
3093                         num_bytes = found.offset;
3094 
3095                 ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0,
3096                                            &roots, false);
3097                 if (ret < 0)
3098                         goto out;
3099                 /* For rescan, just pass old_roots as NULL */
3100                 ret = btrfs_qgroup_account_extent(trans, found.objectid,
3101                                                   num_bytes, NULL, roots);
3102                 if (ret < 0)
3103                         goto out;
3104         }
3105 out:
3106         if (scratch_leaf)
3107                 free_extent_buffer(scratch_leaf);
3108 
3109         if (done && !ret) {
3110                 ret = 1;
3111                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3112         }
3113         return ret;
3114 }
3115 
3116 static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
3117 {
3118         struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
3119                                                      qgroup_rescan_work);
3120         struct btrfs_path *path;
3121         struct btrfs_trans_handle *trans = NULL;
3122         int err = -ENOMEM;
3123         int ret = 0;
3124 
3125         path = btrfs_alloc_path();
3126         if (!path)
3127                 goto out;
3128         /*
3129          * Rescan should only search for commit root, and any later difference
3130          * should be recorded by qgroup
3131          */
3132         path->search_commit_root = 1;
3133         path->skip_locking = 1;
3134 
3135         err = 0;
3136         while (!err && !btrfs_fs_closing(fs_info)) {
3137                 trans = btrfs_start_transaction(fs_info->fs_root, 0);
3138                 if (IS_ERR(trans)) {
3139                         err = PTR_ERR(trans);
3140                         break;
3141                 }
3142                 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
3143                         err = -EINTR;
3144                 } else {
3145                         err = qgroup_rescan_leaf(trans, path);
3146                 }
3147                 if (err > 0)
3148                         btrfs_commit_transaction(trans);
3149                 else
3150                         btrfs_end_transaction(trans);
3151         }
3152 
3153 out:
3154         btrfs_free_path(path);
3155 
3156         mutex_lock(&fs_info->qgroup_rescan_lock);
3157         if (err > 0 &&
3158             fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
3159                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3160         } else if (err < 0) {
3161                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3162         }
3163         mutex_unlock(&fs_info->qgroup_rescan_lock);
3164 
3165         /*
3166          * only update status, since the previous part has already updated the
3167          * qgroup info.
3168          */
3169         trans = btrfs_start_transaction(fs_info->quota_root, 1);
3170         if (IS_ERR(trans)) {
3171                 err = PTR_ERR(trans);
3172                 trans = NULL;
3173                 btrfs_err(fs_info,
3174                           "fail to start transaction for status update: %d",
3175                           err);
3176         }
3177 
3178         mutex_lock(&fs_info->qgroup_rescan_lock);
3179         if (!btrfs_fs_closing(fs_info))
3180                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3181         if (trans) {
3182                 ret = update_qgroup_status_item(trans);
3183                 if (ret < 0) {
3184                         err = ret;
3185                         btrfs_err(fs_info, "fail to update qgroup status: %d",
3186                                   err);
3187                 }
3188         }
3189         fs_info->qgroup_rescan_running = false;
3190         complete_all(&fs_info->qgroup_rescan_completion);
3191         mutex_unlock(&fs_info->qgroup_rescan_lock);
3192 
3193         if (!trans)
3194                 return;
3195 
3196         btrfs_end_transaction(trans);
3197 
3198         if (btrfs_fs_closing(fs_info)) {
3199                 btrfs_info(fs_info, "qgroup scan paused");
3200         } else if (err >= 0) {
3201                 btrfs_info(fs_info, "qgroup scan completed%s",
3202                         err > 0 ? " (inconsistency flag cleared)" : "");
3203         } else {
3204                 btrfs_err(fs_info, "qgroup scan failed with %d", err);
3205         }
3206 }
3207 
3208 /*
3209  * Checks that (a) no rescan is running and (b) quota is enabled. Allocates all
3210  * memory required for the rescan context.
3211  */
3212 static int
3213 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
3214                    int init_flags)
3215 {
3216         int ret = 0;
3217 
3218         if (!init_flags) {
3219                 /* we're resuming qgroup rescan at mount time */
3220                 if (!(fs_info->qgroup_flags &
3221                       BTRFS_QGROUP_STATUS_FLAG_RESCAN)) {
3222                         btrfs_warn(fs_info,
3223                         "qgroup rescan init failed, qgroup is not enabled");
3224                         ret = -EINVAL;
3225                 } else if (!(fs_info->qgroup_flags &
3226                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3227                         btrfs_warn(fs_info,
3228                         "qgroup rescan init failed, qgroup rescan is not queued");
3229                         ret = -EINVAL;
3230                 }
3231 
3232                 if (ret)
3233                         return ret;
3234         }
3235 
3236         mutex_lock(&fs_info->qgroup_rescan_lock);
3237         spin_lock(&fs_info->qgroup_lock);
3238 
3239         if (init_flags) {
3240                 if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
3241                         btrfs_warn(fs_info,
3242                                    "qgroup rescan is already in progress");
3243                         ret = -EINPROGRESS;
3244                 } else if (!(fs_info->qgroup_flags &
3245                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3246                         btrfs_warn(fs_info,
3247                         "qgroup rescan init failed, qgroup is not enabled");
3248                         ret = -EINVAL;
3249                 }
3250 
3251                 if (ret) {
3252                         spin_unlock(&fs_info->qgroup_lock);
3253                         mutex_unlock(&fs_info->qgroup_rescan_lock);
3254                         return ret;
3255                 }
3256                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3257         }
3258 
3259         memset(&fs_info->qgroup_rescan_progress, 0,
3260                 sizeof(fs_info->qgroup_rescan_progress));
3261         fs_info->qgroup_rescan_progress.objectid = progress_objectid;
3262         init_completion(&fs_info->qgroup_rescan_completion);
3263         fs_info->qgroup_rescan_running = true;
3264 
3265         spin_unlock(&fs_info->qgroup_lock);
3266         mutex_unlock(&fs_info->qgroup_rescan_lock);
3267 
3268         memset(&fs_info->qgroup_rescan_work, 0,
3269                sizeof(fs_info->qgroup_rescan_work));
3270         btrfs_init_work(&fs_info->qgroup_rescan_work,
3271                         btrfs_qgroup_rescan_helper,
3272                         btrfs_qgroup_rescan_worker, NULL, NULL);
3273         return 0;
3274 }
3275 
3276 static void
3277 qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info)
3278 {
3279         struct rb_node *n;
3280         struct btrfs_qgroup *qgroup;
3281 
3282         spin_lock(&fs_info->qgroup_lock);
3283         /* clear all current qgroup tracking information */
3284         for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
3285                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
3286                 qgroup->rfer = 0;
3287                 qgroup->rfer_cmpr = 0;
3288                 qgroup->excl = 0;
3289                 qgroup->excl_cmpr = 0;
3290                 qgroup_dirty(fs_info, qgroup);
3291         }
3292         spin_unlock(&fs_info->qgroup_lock);
3293 }
3294 
3295 int
3296 btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
3297 {
3298         int ret = 0;
3299         struct btrfs_trans_handle *trans;
3300 
3301         ret = qgroup_rescan_init(fs_info, 0, 1);
3302         if (ret)
3303                 return ret;
3304 
3305         /*
3306          * We have set the rescan_progress to 0, which means no more
3307          * delayed refs will be accounted by btrfs_qgroup_account_ref.
3308          * However, btrfs_qgroup_account_ref may be right after its call
3309          * to btrfs_find_all_roots, in which case it would still do the
3310          * accounting.
3311          * To solve this, we're committing the transaction, which will
3312          * ensure we run all delayed refs and only after that, we are
3313          * going to clear all tracking information for a clean start.
3314          */
3315 
3316         trans = btrfs_join_transaction(fs_info->fs_root);
3317         if (IS_ERR(trans)) {
3318                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3319                 return PTR_ERR(trans);
3320         }
3321         ret = btrfs_commit_transaction(trans);
3322         if (ret) {
3323                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3324                 return ret;
3325         }
3326 
3327         qgroup_rescan_zero_tracking(fs_info);
3328 
3329         btrfs_queue_work(fs_info->qgroup_rescan_workers,
3330                          &fs_info->qgroup_rescan_work);
3331 
3332         return 0;
3333 }
3334 
3335 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
3336                                      bool interruptible)
3337 {
3338         int running;
3339         int ret = 0;
3340 
3341         mutex_lock(&fs_info->qgroup_rescan_lock);
3342         spin_lock(&fs_info->qgroup_lock);
3343         running = fs_info->qgroup_rescan_running;
3344         spin_unlock(&fs_info->qgroup_lock);
3345         mutex_unlock(&fs_info->qgroup_rescan_lock);
3346 
3347         if (!running)
3348                 return 0;
3349 
3350         if (interruptible)
3351                 ret = wait_for_completion_interruptible(
3352                                         &fs_info->qgroup_rescan_completion);
3353         else
3354                 wait_for_completion(&fs_info->qgroup_rescan_completion);
3355 
3356         return ret;
3357 }
3358 
3359 /*
3360  * this is only called from open_ctree where we're still single threaded, thus
3361  * locking is omitted here.
3362  */
3363 void
3364 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
3365 {
3366         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
3367                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
3368                                  &fs_info->qgroup_rescan_work);
3369 }
3370 
3371 /*
3372  * Reserve qgroup space for range [start, start + len).
3373  *
3374  * This function will either reserve space from related qgroups or doing
3375  * nothing if the range is already reserved.
3376  *
3377  * Return 0 for successful reserve
3378  * Return <0 for error (including -EQUOT)
3379  *
3380  * NOTE: this function may sleep for memory allocation.
3381  *       if btrfs_qgroup_reserve_data() is called multiple times with
3382  *       same @reserved, caller must ensure when error happens it's OK
3383  *       to free *ALL* reserved space.
3384  */
3385 int btrfs_qgroup_reserve_data(struct inode *inode,
3386                         struct extent_changeset **reserved_ret, u64 start,
3387                         u64 len)
3388 {
3389         struct btrfs_root *root = BTRFS_I(inode)->root;
3390         struct ulist_node *unode;
3391         struct ulist_iterator uiter;
3392         struct extent_changeset *reserved;
3393         u64 orig_reserved;
3394         u64 to_reserve;
3395         int ret;
3396 
3397         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags) ||
3398             !is_fstree(root->root_key.objectid) || len == 0)
3399                 return 0;
3400 
3401         /* @reserved parameter is mandatory for qgroup */
3402         if (WARN_ON(!reserved_ret))
3403                 return -EINVAL;
3404         if (!*reserved_ret) {
3405                 *reserved_ret = extent_changeset_alloc();
3406                 if (!*reserved_ret)
3407                         return -ENOMEM;
3408         }
3409         reserved = *reserved_ret;
3410         /* Record already reserved space */
3411         orig_reserved = reserved->bytes_changed;
3412         ret = set_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
3413                         start + len -1, EXTENT_QGROUP_RESERVED, reserved);
3414 
3415         /* Newly reserved space */
3416         to_reserve = reserved->bytes_changed - orig_reserved;
3417         trace_btrfs_qgroup_reserve_data(inode, start, len,
3418                                         to_reserve, QGROUP_RESERVE);
3419         if (ret < 0)
3420                 goto cleanup;
3421         ret = qgroup_reserve(root, to_reserve, true, BTRFS_QGROUP_RSV_DATA);
3422         if (ret < 0)
3423                 goto cleanup;
3424 
3425         return ret;
3426 
3427 cleanup:
3428         /* cleanup *ALL* already reserved ranges */
3429         ULIST_ITER_INIT(&uiter);
3430         while ((unode = ulist_next(&reserved->range_changed, &uiter)))
3431                 clear_extent_bit(&BTRFS_I(inode)->io_tree, unode->val,
3432                                  unode->aux, EXTENT_QGROUP_RESERVED, 0, 0, NULL);
3433         /* Also free data bytes of already reserved one */
3434         btrfs_qgroup_free_refroot(root->fs_info, root->root_key.objectid,
3435                                   orig_reserved, BTRFS_QGROUP_RSV_DATA);
3436         extent_changeset_release(reserved);
3437         return ret;
3438 }
3439 
3440 /* Free ranges specified by @reserved, normally in error path */
3441 static int qgroup_free_reserved_data(struct inode *inode,
3442                         struct extent_changeset *reserved, u64 start, u64 len)
3443 {
3444         struct btrfs_root *root = BTRFS_I(inode)->root;
3445         struct ulist_node *unode;
3446         struct ulist_iterator uiter;
3447         struct extent_changeset changeset;
3448         int freed = 0;
3449         int ret;
3450 
3451         extent_changeset_init(&changeset);
3452         len = round_up(start + len, root->fs_info->sectorsize);
3453         start = round_down(start, root->fs_info->sectorsize);
3454 
3455         ULIST_ITER_INIT(&uiter);
3456         while ((unode = ulist_next(&reserved->range_changed, &uiter))) {
3457                 u64 range_start = unode->val;
3458                 /* unode->aux is the inclusive end */
3459                 u64 range_len = unode->aux - range_start + 1;
3460                 u64 free_start;
3461                 u64 free_len;
3462 
3463                 extent_changeset_release(&changeset);
3464 
3465                 /* Only free range in range [start, start + len) */
3466                 if (range_start >= start + len ||
3467                     range_start + range_len <= start)
3468                         continue;
3469                 free_start = max(range_start, start);
3470                 free_len = min(start + len, range_start + range_len) -
3471                            free_start;
3472                 /*
3473                  * TODO: To also modify reserved->ranges_reserved to reflect
3474                  * the modification.
3475                  *
3476                  * However as long as we free qgroup reserved according to
3477                  * EXTENT_QGROUP_RESERVED, we won't double free.
3478                  * So not need to rush.
3479                  */
3480                 ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree,
3481                                 free_start, free_start + free_len - 1,
3482                                 EXTENT_QGROUP_RESERVED, &changeset);
3483                 if (ret < 0)
3484                         goto out;
3485                 freed += changeset.bytes_changed;
3486         }
3487         btrfs_qgroup_free_refroot(root->fs_info, root->root_key.objectid, freed,
3488                                   BTRFS_QGROUP_RSV_DATA);
3489         ret = freed;
3490 out:
3491         extent_changeset_release(&changeset);
3492         return ret;
3493 }
3494 
3495 static int __btrfs_qgroup_release_data(struct inode *inode,
3496                         struct extent_changeset *reserved, u64 start, u64 len,
3497                         int free)
3498 {
3499         struct extent_changeset changeset;
3500         int trace_op = QGROUP_RELEASE;
3501         int ret;
3502 
3503         if (!test_bit(BTRFS_FS_QUOTA_ENABLED,
3504                       &BTRFS_I(inode)->root->fs_info->flags))
3505                 return 0;
3506 
3507         /* In release case, we shouldn't have @reserved */
3508         WARN_ON(!free && reserved);
3509         if (free && reserved)
3510                 return qgroup_free_reserved_data(inode, reserved, start, len);
3511         extent_changeset_init(&changeset);
3512         ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start, 
3513                         start + len -1, EXTENT_QGROUP_RESERVED, &changeset);
3514         if (ret < 0)
3515                 goto out;
3516 
3517         if (free)
3518                 trace_op = QGROUP_FREE;
3519         trace_btrfs_qgroup_release_data(inode, start, len,
3520                                         changeset.bytes_changed, trace_op);
3521         if (free)
3522                 btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3523                                 BTRFS_I(inode)->root->root_key.objectid,
3524                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3525         ret = changeset.bytes_changed;
3526 out:
3527         extent_changeset_release(&changeset);
3528         return ret;
3529 }
3530 
3531 /*
3532  * Free a reserved space range from io_tree and related qgroups
3533  *
3534  * Should be called when a range of pages get invalidated before reaching disk.
3535  * Or for error cleanup case.
3536  * if @reserved is given, only reserved range in [@start, @start + @len) will
3537  * be freed.
3538  *
3539  * For data written to disk, use btrfs_qgroup_release_data().
3540  *
3541  * NOTE: This function may sleep for memory allocation.
3542  */
3543 int btrfs_qgroup_free_data(struct inode *inode,
3544                         struct extent_changeset *reserved, u64 start, u64 len)
3545 {
3546         return __btrfs_qgroup_release_data(inode, reserved, start, len, 1);
3547 }
3548 
3549 /*
3550  * Release a reserved space range from io_tree only.
3551  *
3552  * Should be called when a range of pages get written to disk and corresponding
3553  * FILE_EXTENT is inserted into corresponding root.
3554  *
3555  * Since new qgroup accounting framework will only update qgroup numbers at
3556  * commit_transaction() time, its reserved space shouldn't be freed from
3557  * related qgroups.
3558  *
3559  * But we should release the range from io_tree, to allow further write to be
3560  * COWed.
3561  *
3562  * NOTE: This function may sleep for memory allocation.
3563  */
3564 int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len)
3565 {
3566         return __btrfs_qgroup_release_data(inode, NULL, start, len, 0);
3567 }
3568 
3569 static void add_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3570                               enum btrfs_qgroup_rsv_type type)
3571 {
3572         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3573             type != BTRFS_QGROUP_RSV_META_PERTRANS)
3574                 return;
3575         if (num_bytes == 0)
3576                 return;
3577 
3578         spin_lock(&root->qgroup_meta_rsv_lock);
3579         if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
3580                 root->qgroup_meta_rsv_prealloc += num_bytes;
3581         else
3582                 root->qgroup_meta_rsv_pertrans += num_bytes;
3583         spin_unlock(&root->qgroup_meta_rsv_lock);
3584 }
3585 
3586 static int sub_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3587                              enum btrfs_qgroup_rsv_type type)
3588 {
3589         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3590             type != BTRFS_QGROUP_RSV_META_PERTRANS)
3591                 return 0;
3592         if (num_bytes == 0)
3593                 return 0;
3594 
3595         spin_lock(&root->qgroup_meta_rsv_lock);
3596         if (type == BTRFS_QGROUP_RSV_META_PREALLOC) {
3597                 num_bytes = min_t(u64, root->qgroup_meta_rsv_prealloc,
3598                                   num_bytes);
3599                 root->qgroup_meta_rsv_prealloc -= num_bytes;
3600         } else {
3601                 num_bytes = min_t(u64, root->qgroup_meta_rsv_pertrans,
3602                                   num_bytes);
3603                 root->qgroup_meta_rsv_pertrans -= num_bytes;
3604         }
3605         spin_unlock(&root->qgroup_meta_rsv_lock);
3606         return num_bytes;
3607 }
3608 
3609 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
3610                                 enum btrfs_qgroup_rsv_type type, bool enforce)
3611 {
3612         struct btrfs_fs_info *fs_info = root->fs_info;
3613         int ret;
3614 
3615         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3616             !is_fstree(root->root_key.objectid) || num_bytes == 0)
3617                 return 0;
3618 
3619         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3620         trace_qgroup_meta_reserve(root, (s64)num_bytes, type);
3621         ret = qgroup_reserve(root, num_bytes, enforce, type);
3622         if (ret < 0)
3623                 return ret;
3624         /*
3625          * Record what we have reserved into root.
3626          *
3627          * To avoid quota disabled->enabled underflow.
3628          * In that case, we may try to free space we haven't reserved
3629          * (since quota was disabled), so record what we reserved into root.
3630          * And ensure later release won't underflow this number.
3631          */
3632         add_root_meta_rsv(root, num_bytes, type);
3633         return ret;
3634 }
3635 
3636 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root)
3637 {
3638         struct btrfs_fs_info *fs_info = root->fs_info;
3639 
3640         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3641             !is_fstree(root->root_key.objectid))
3642                 return;
3643 
3644         /* TODO: Update trace point to handle such free */
3645         trace_qgroup_meta_free_all_pertrans(root);
3646         /* Special value -1 means to free all reserved space */
3647         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid, (u64)-1,
3648                                   BTRFS_QGROUP_RSV_META_PERTRANS);
3649 }
3650 
3651 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
3652                               enum btrfs_qgroup_rsv_type type)
3653 {
3654         struct btrfs_fs_info *fs_info = root->fs_info;
3655 
3656         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3657             !is_fstree(root->root_key.objectid))
3658                 return;
3659 
3660         /*
3661          * reservation for META_PREALLOC can happen before quota is enabled,
3662          * which can lead to underflow.
3663          * Here ensure we will only free what we really have reserved.
3664          */
3665         num_bytes = sub_root_meta_rsv(root, num_bytes, type);
3666         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3667         trace_qgroup_meta_reserve(root, -(s64)num_bytes, type);
3668         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
3669                                   num_bytes, type);
3670 }
3671 
3672 static void qgroup_convert_meta(struct btrfs_fs_info *fs_info, u64 ref_root,
3673                                 int num_bytes)
3674 {
3675         struct btrfs_root *quota_root = fs_info->quota_root;
3676         struct btrfs_qgroup *qgroup;
3677         struct ulist_node *unode;
3678         struct ulist_iterator uiter;
3679         int ret = 0;
3680 
3681         if (num_bytes == 0)
3682                 return;
3683         if (!quota_root)
3684                 return;
3685 
3686         spin_lock(&fs_info->qgroup_lock);
3687         qgroup = find_qgroup_rb(fs_info, ref_root);
3688         if (!qgroup)
3689                 goto out;
3690         ulist_reinit(fs_info->qgroup_ulist);
3691         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
3692                        qgroup_to_aux(qgroup), GFP_ATOMIC);
3693         if (ret < 0)
3694                 goto out;
3695         ULIST_ITER_INIT(&uiter);
3696         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
3697                 struct btrfs_qgroup *qg;
3698                 struct btrfs_qgroup_list *glist;
3699 
3700                 qg = unode_aux_to_qgroup(unode);
3701 
3702                 qgroup_rsv_release(fs_info, qg, num_bytes,
3703                                 BTRFS_QGROUP_RSV_META_PREALLOC);
3704                 qgroup_rsv_add(fs_info, qg, num_bytes,
3705                                 BTRFS_QGROUP_RSV_META_PERTRANS);
3706                 list_for_each_entry(glist, &qg->groups, next_group) {
3707                         ret = ulist_add(fs_info->qgroup_ulist,
3708                                         glist->group->qgroupid,
3709                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
3710                         if (ret < 0)
3711                                 goto out;
3712                 }
3713         }
3714 out:
3715         spin_unlock(&fs_info->qgroup_lock);
3716 }
3717 
3718 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes)
3719 {
3720         struct btrfs_fs_info *fs_info = root->fs_info;
3721 
3722         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3723             !is_fstree(root->root_key.objectid))
3724                 return;
3725         /* Same as btrfs_qgroup_free_meta_prealloc() */
3726         num_bytes = sub_root_meta_rsv(root, num_bytes,
3727                                       BTRFS_QGROUP_RSV_META_PREALLOC);
3728         trace_qgroup_meta_convert(root, num_bytes);
3729         qgroup_convert_meta(fs_info, root->root_key.objectid, num_bytes);
3730 }
3731 
3732 /*
3733  * Check qgroup reserved space leaking, normally at destroy inode
3734  * time
3735  */
3736 void btrfs_qgroup_check_reserved_leak(struct inode *inode)
3737 {
3738         struct extent_changeset changeset;
3739         struct ulist_node *unode;
3740         struct ulist_iterator iter;
3741         int ret;
3742 
3743         extent_changeset_init(&changeset);
3744         ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, 0, (u64)-1,
3745                         EXTENT_QGROUP_RESERVED, &changeset);
3746 
3747         WARN_ON(ret < 0);
3748         if (WARN_ON(changeset.bytes_changed)) {
3749                 ULIST_ITER_INIT(&iter);
3750                 while ((unode = ulist_next(&changeset.range_changed, &iter))) {
3751                         btrfs_warn(BTRFS_I(inode)->root->fs_info,
3752                                 "leaking qgroup reserved space, ino: %lu, start: %llu, end: %llu",
3753                                 inode->i_ino, unode->val, unode->aux);
3754                 }
3755                 btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3756                                 BTRFS_I(inode)->root->root_key.objectid,
3757                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3758 
3759         }
3760         extent_changeset_release(&changeset);
3761 }
3762 
3763 void btrfs_qgroup_init_swapped_blocks(
3764         struct btrfs_qgroup_swapped_blocks *swapped_blocks)
3765 {
3766         int i;
3767 
3768         spin_lock_init(&swapped_blocks->lock);
3769         for (i = 0; i < BTRFS_MAX_LEVEL; i++)
3770                 swapped_blocks->blocks[i] = RB_ROOT;
3771         swapped_blocks->swapped = false;
3772 }
3773 
3774 /*
3775  * Delete all swapped blocks record of @root.
3776  * Every record here means we skipped a full subtree scan for qgroup.
3777  *
3778  * Gets called when committing one transaction.
3779  */
3780 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root)
3781 {
3782         struct btrfs_qgroup_swapped_blocks *swapped_blocks;
3783         int i;
3784 
3785         swapped_blocks = &root->swapped_blocks;
3786 
3787         spin_lock(&swapped_blocks->lock);
3788         if (!swapped_blocks->swapped)
3789                 goto out;
3790         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3791                 struct rb_root *cur_root = &swapped_blocks->blocks[i];
3792                 struct btrfs_qgroup_swapped_block *entry;
3793                 struct btrfs_qgroup_swapped_block *next;
3794 
3795                 rbtree_postorder_for_each_entry_safe(entry, next, cur_root,
3796                                                      node)
3797                         kfree(entry);
3798                 swapped_blocks->blocks[i] = RB_ROOT;
3799         }
3800         swapped_blocks->swapped = false;
3801 out:
3802         spin_unlock(&swapped_blocks->lock);
3803 }
3804 
3805 /*
3806  * Add subtree roots record into @subvol_root.
3807  *
3808  * @subvol_root:        tree root of the subvolume tree get swapped
3809  * @bg:                 block group under balance
3810  * @subvol_parent/slot: pointer to the subtree root in subvolume tree
3811  * @reloc_parent/slot:  pointer to the subtree root in reloc tree
3812  *                      BOTH POINTERS ARE BEFORE TREE SWAP
3813  * @last_snapshot:      last snapshot generation of the subvolume tree
3814  */
3815 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
3816                 struct btrfs_root *subvol_root,
3817                 struct btrfs_block_group_cache *bg,
3818                 struct extent_buffer *subvol_parent, int subvol_slot,
3819                 struct extent_buffer *reloc_parent, int reloc_slot,
3820                 u64 last_snapshot)
3821 {
3822         struct btrfs_fs_info *fs_info = subvol_root->fs_info;
3823         struct btrfs_qgroup_swapped_blocks *blocks = &subvol_root->swapped_blocks;
3824         struct btrfs_qgroup_swapped_block *block;
3825         struct rb_node **cur;
3826         struct rb_node *parent = NULL;
3827         int level = btrfs_header_level(subvol_parent) - 1;
3828         int ret = 0;
3829 
3830         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
3831                 return 0;
3832 
3833         if (btrfs_node_ptr_generation(subvol_parent, subvol_slot) >
3834             btrfs_node_ptr_generation(reloc_parent, reloc_slot)) {
3835                 btrfs_err_rl(fs_info,
3836                 "%s: bad parameter order, subvol_gen=%llu reloc_gen=%llu",
3837                         __func__,
3838                         btrfs_node_ptr_generation(subvol_parent, subvol_slot),
3839                         btrfs_node_ptr_generation(reloc_parent, reloc_slot));
3840                 return -EUCLEAN;
3841         }
3842 
3843         block = kmalloc(sizeof(*block), GFP_NOFS);
3844         if (!block) {
3845                 ret = -ENOMEM;
3846                 goto out;
3847         }
3848 
3849         /*
3850          * @reloc_parent/slot is still before swap, while @block is going to
3851          * record the bytenr after swap, so we do the swap here.
3852          */
3853         block->subvol_bytenr = btrfs_node_blockptr(reloc_parent, reloc_slot);
3854         block->subvol_generation = btrfs_node_ptr_generation(reloc_parent,
3855                                                              reloc_slot);
3856         block->reloc_bytenr = btrfs_node_blockptr(subvol_parent, subvol_slot);
3857         block->reloc_generation = btrfs_node_ptr_generation(subvol_parent,
3858                                                             subvol_slot);
3859         block->last_snapshot = last_snapshot;
3860         block->level = level;
3861 
3862         /*
3863          * If we have bg == NULL, we're called from btrfs_recover_relocation(),
3864          * no one else can modify tree blocks thus we qgroup will not change
3865          * no matter the value of trace_leaf.
3866          */
3867         if (bg && bg->flags & BTRFS_BLOCK_GROUP_DATA)
3868                 block->trace_leaf = true;
3869         else
3870                 block->trace_leaf = false;
3871         btrfs_node_key_to_cpu(reloc_parent, &block->first_key, reloc_slot);
3872 
3873         /* Insert @block into @blocks */
3874         spin_lock(&blocks->lock);
3875         cur = &blocks->blocks[level].rb_node;
3876         while (*cur) {
3877                 struct btrfs_qgroup_swapped_block *entry;
3878 
3879                 parent = *cur;
3880                 entry = rb_entry(parent, struct btrfs_qgroup_swapped_block,
3881                                  node);
3882 
3883                 if (entry->subvol_bytenr < block->subvol_bytenr) {
3884                         cur = &(*cur)->rb_left;
3885                 } else if (entry->subvol_bytenr > block->subvol_bytenr) {
3886                         cur = &(*cur)->rb_right;
3887                 } else {
3888                         if (entry->subvol_generation !=
3889                                         block->subvol_generation ||
3890                             entry->reloc_bytenr != block->reloc_bytenr ||
3891                             entry->reloc_generation !=
3892                                         block->reloc_generation) {
3893                                 /*
3894                                  * Duplicated but mismatch entry found.
3895                                  * Shouldn't happen.
3896                                  *
3897                                  * Marking qgroup inconsistent should be enough
3898                                  * for end users.
3899                                  */
3900                                 WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
3901                                 ret = -EEXIST;
3902                         }
3903                         kfree(block);
3904                         goto out_unlock;
3905                 }
3906         }
3907         rb_link_node(&block->node, parent, cur);
3908         rb_insert_color(&block->node, &blocks->blocks[level]);
3909         blocks->swapped = true;
3910 out_unlock:
3911         spin_unlock(&blocks->lock);
3912 out:
3913         if (ret < 0)
3914                 fs_info->qgroup_flags |=
3915                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3916         return ret;
3917 }
3918 
3919 /*
3920  * Check if the tree block is a subtree root, and if so do the needed
3921  * delayed subtree trace for qgroup.
3922  *
3923  * This is called during btrfs_cow_block().
3924  */
3925 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
3926                                          struct btrfs_root *root,
3927                                          struct extent_buffer *subvol_eb)
3928 {
3929         struct btrfs_fs_info *fs_info = root->fs_info;
3930         struct btrfs_qgroup_swapped_blocks *blocks = &root->swapped_blocks;
3931         struct btrfs_qgroup_swapped_block *block;
3932         struct extent_buffer *reloc_eb = NULL;
3933         struct rb_node *node;
3934         bool found = false;
3935         bool swapped = false;
3936         int level = btrfs_header_level(subvol_eb);
3937         int ret = 0;
3938         int i;
3939 
3940         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
3941                 return 0;
3942         if (!is_fstree(root->root_key.objectid) || !root->reloc_root)
3943                 return 0;
3944 
3945         spin_lock(&blocks->lock);
3946         if (!blocks->swapped) {
3947                 spin_unlock(&blocks->lock);
3948                 return 0;
3949         }
3950         node = blocks->blocks[level].rb_node;
3951 
3952         while (node) {
3953                 block = rb_entry(node, struct btrfs_qgroup_swapped_block, node);
3954                 if (block->subvol_bytenr < subvol_eb->start) {
3955                         node = node->rb_left;
3956                 } else if (block->subvol_bytenr > subvol_eb->start) {
3957                         node = node->rb_right;
3958                 } else {
3959                         found = true;
3960                         break;
3961                 }
3962         }
3963         if (!found) {
3964                 spin_unlock(&blocks->lock);
3965                 goto out;
3966         }
3967         /* Found one, remove it from @blocks first and update blocks->swapped */
3968         rb_erase(&block->node, &blocks->blocks[level]);
3969         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3970                 if (RB_EMPTY_ROOT(&blocks->blocks[i])) {
3971                         swapped = true;
3972                         break;
3973                 }
3974         }
3975         blocks->swapped = swapped;
3976         spin_unlock(&blocks->lock);
3977 
3978         /* Read out reloc subtree root */
3979         reloc_eb = read_tree_block(fs_info, block->reloc_bytenr,
3980                                    block->reloc_generation, block->level,
3981                                    &block->first_key);
3982         if (IS_ERR(reloc_eb)) {
3983                 ret = PTR_ERR(reloc_eb);
3984                 reloc_eb = NULL;
3985                 goto free_out;
3986         }
3987         if (!extent_buffer_uptodate(reloc_eb)) {
3988                 ret = -EIO;
3989                 goto free_out;
3990         }
3991 
3992         ret = qgroup_trace_subtree_swap(trans, reloc_eb, subvol_eb,
3993                         block->last_snapshot, block->trace_leaf);
3994 free_out:
3995         kfree(block);
3996         free_extent_buffer(reloc_eb);
3997 out:
3998         if (ret < 0) {
3999                 btrfs_err_rl(fs_info,
4000                              "failed to account subtree at bytenr %llu: %d",
4001                              subvol_eb->start, ret);
4002                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
4003         }
4004         return ret;
4005 }
4006 

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