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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, fs_info,
922                                        BTRFS_QUOTA_TREE_OBJECTID);
923         if (IS_ERR(quota_root)) {
924                 ret =  PTR_ERR(quota_root);
925                 btrfs_abort_transaction(trans, ret);
926                 goto out;
927         }
928 
929         path = btrfs_alloc_path();
930         if (!path) {
931                 ret = -ENOMEM;
932                 btrfs_abort_transaction(trans, ret);
933                 goto out_free_root;
934         }
935 
936         key.objectid = 0;
937         key.type = BTRFS_QGROUP_STATUS_KEY;
938         key.offset = 0;
939 
940         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
941                                       sizeof(*ptr));
942         if (ret) {
943                 btrfs_abort_transaction(trans, ret);
944                 goto out_free_path;
945         }
946 
947         leaf = path->nodes[0];
948         ptr = btrfs_item_ptr(leaf, path->slots[0],
949                                  struct btrfs_qgroup_status_item);
950         btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
951         btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
952         fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON |
953                                 BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
954         btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags);
955         btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
956 
957         btrfs_mark_buffer_dirty(leaf);
958 
959         key.objectid = 0;
960         key.type = BTRFS_ROOT_REF_KEY;
961         key.offset = 0;
962 
963         btrfs_release_path(path);
964         ret = btrfs_search_slot_for_read(tree_root, &key, path, 1, 0);
965         if (ret > 0)
966                 goto out_add_root;
967         if (ret < 0) {
968                 btrfs_abort_transaction(trans, ret);
969                 goto out_free_path;
970         }
971 
972         while (1) {
973                 slot = path->slots[0];
974                 leaf = path->nodes[0];
975                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
976 
977                 if (found_key.type == BTRFS_ROOT_REF_KEY) {
978                         ret = add_qgroup_item(trans, quota_root,
979                                               found_key.offset);
980                         if (ret) {
981                                 btrfs_abort_transaction(trans, ret);
982                                 goto out_free_path;
983                         }
984 
985                         qgroup = add_qgroup_rb(fs_info, found_key.offset);
986                         if (IS_ERR(qgroup)) {
987                                 ret = PTR_ERR(qgroup);
988                                 btrfs_abort_transaction(trans, ret);
989                                 goto out_free_path;
990                         }
991                 }
992                 ret = btrfs_next_item(tree_root, path);
993                 if (ret < 0) {
994                         btrfs_abort_transaction(trans, ret);
995                         goto out_free_path;
996                 }
997                 if (ret)
998                         break;
999         }
1000 
1001 out_add_root:
1002         btrfs_release_path(path);
1003         ret = add_qgroup_item(trans, quota_root, BTRFS_FS_TREE_OBJECTID);
1004         if (ret) {
1005                 btrfs_abort_transaction(trans, ret);
1006                 goto out_free_path;
1007         }
1008 
1009         qgroup = add_qgroup_rb(fs_info, BTRFS_FS_TREE_OBJECTID);
1010         if (IS_ERR(qgroup)) {
1011                 ret = PTR_ERR(qgroup);
1012                 btrfs_abort_transaction(trans, ret);
1013                 goto out_free_path;
1014         }
1015 
1016         ret = btrfs_commit_transaction(trans);
1017         trans = NULL;
1018         if (ret)
1019                 goto out_free_path;
1020 
1021         /*
1022          * Set quota enabled flag after committing the transaction, to avoid
1023          * deadlocks on fs_info->qgroup_ioctl_lock with concurrent snapshot
1024          * creation.
1025          */
1026         spin_lock(&fs_info->qgroup_lock);
1027         fs_info->quota_root = quota_root;
1028         set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1029         spin_unlock(&fs_info->qgroup_lock);
1030 
1031         ret = qgroup_rescan_init(fs_info, 0, 1);
1032         if (!ret) {
1033                 qgroup_rescan_zero_tracking(fs_info);
1034                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
1035                                  &fs_info->qgroup_rescan_work);
1036         }
1037 
1038 out_free_path:
1039         btrfs_free_path(path);
1040 out_free_root:
1041         if (ret) {
1042                 free_extent_buffer(quota_root->node);
1043                 free_extent_buffer(quota_root->commit_root);
1044                 kfree(quota_root);
1045         }
1046 out:
1047         if (ret) {
1048                 ulist_free(fs_info->qgroup_ulist);
1049                 fs_info->qgroup_ulist = NULL;
1050                 if (trans)
1051                         btrfs_end_transaction(trans);
1052         }
1053         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1054         return ret;
1055 }
1056 
1057 int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
1058 {
1059         struct btrfs_root *quota_root;
1060         struct btrfs_trans_handle *trans = NULL;
1061         int ret = 0;
1062 
1063         mutex_lock(&fs_info->qgroup_ioctl_lock);
1064         if (!fs_info->quota_root)
1065                 goto out;
1066 
1067         /*
1068          * 1 For the root item
1069          *
1070          * We should also reserve enough items for the quota tree deletion in
1071          * btrfs_clean_quota_tree but this is not done.
1072          */
1073         trans = btrfs_start_transaction(fs_info->tree_root, 1);
1074         if (IS_ERR(trans)) {
1075                 ret = PTR_ERR(trans);
1076                 goto out;
1077         }
1078 
1079         clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1080         btrfs_qgroup_wait_for_completion(fs_info, false);
1081         spin_lock(&fs_info->qgroup_lock);
1082         quota_root = fs_info->quota_root;
1083         fs_info->quota_root = NULL;
1084         fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
1085         spin_unlock(&fs_info->qgroup_lock);
1086 
1087         btrfs_free_qgroup_config(fs_info);
1088 
1089         ret = btrfs_clean_quota_tree(trans, quota_root);
1090         if (ret) {
1091                 btrfs_abort_transaction(trans, ret);
1092                 goto end_trans;
1093         }
1094 
1095         ret = btrfs_del_root(trans, &quota_root->root_key);
1096         if (ret) {
1097                 btrfs_abort_transaction(trans, ret);
1098                 goto end_trans;
1099         }
1100 
1101         list_del(&quota_root->dirty_list);
1102 
1103         btrfs_tree_lock(quota_root->node);
1104         clean_tree_block(fs_info, quota_root->node);
1105         btrfs_tree_unlock(quota_root->node);
1106         btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1);
1107 
1108         free_extent_buffer(quota_root->node);
1109         free_extent_buffer(quota_root->commit_root);
1110         kfree(quota_root);
1111 
1112 end_trans:
1113         ret = btrfs_end_transaction(trans);
1114 out:
1115         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1116         return ret;
1117 }
1118 
1119 static void qgroup_dirty(struct btrfs_fs_info *fs_info,
1120                          struct btrfs_qgroup *qgroup)
1121 {
1122         if (list_empty(&qgroup->dirty))
1123                 list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
1124 }
1125 
1126 /*
1127  * The easy accounting, we're updating qgroup relationship whose child qgroup
1128  * only has exclusive extents.
1129  *
1130  * In this case, all exclusive extents will also be exclusive for parent, so
1131  * excl/rfer just get added/removed.
1132  *
1133  * So is qgroup reservation space, which should also be added/removed to
1134  * parent.
1135  * Or when child tries to release reservation space, parent will underflow its
1136  * reservation (for relationship adding case).
1137  *
1138  * Caller should hold fs_info->qgroup_lock.
1139  */
1140 static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
1141                                     struct ulist *tmp, u64 ref_root,
1142                                     struct btrfs_qgroup *src, int sign)
1143 {
1144         struct btrfs_qgroup *qgroup;
1145         struct btrfs_qgroup_list *glist;
1146         struct ulist_node *unode;
1147         struct ulist_iterator uiter;
1148         u64 num_bytes = src->excl;
1149         int ret = 0;
1150 
1151         qgroup = find_qgroup_rb(fs_info, ref_root);
1152         if (!qgroup)
1153                 goto out;
1154 
1155         qgroup->rfer += sign * num_bytes;
1156         qgroup->rfer_cmpr += sign * num_bytes;
1157 
1158         WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1159         qgroup->excl += sign * num_bytes;
1160         qgroup->excl_cmpr += sign * num_bytes;
1161 
1162         if (sign > 0)
1163                 qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1164         else
1165                 qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1166 
1167         qgroup_dirty(fs_info, qgroup);
1168 
1169         /* Get all of the parent groups that contain this qgroup */
1170         list_for_each_entry(glist, &qgroup->groups, next_group) {
1171                 ret = ulist_add(tmp, glist->group->qgroupid,
1172                                 qgroup_to_aux(glist->group), GFP_ATOMIC);
1173                 if (ret < 0)
1174                         goto out;
1175         }
1176 
1177         /* Iterate all of the parents and adjust their reference counts */
1178         ULIST_ITER_INIT(&uiter);
1179         while ((unode = ulist_next(tmp, &uiter))) {
1180                 qgroup = unode_aux_to_qgroup(unode);
1181                 qgroup->rfer += sign * num_bytes;
1182                 qgroup->rfer_cmpr += sign * num_bytes;
1183                 WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1184                 qgroup->excl += sign * num_bytes;
1185                 if (sign > 0)
1186                         qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1187                 else
1188                         qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1189                 qgroup->excl_cmpr += sign * num_bytes;
1190                 qgroup_dirty(fs_info, qgroup);
1191 
1192                 /* Add any parents of the parents */
1193                 list_for_each_entry(glist, &qgroup->groups, next_group) {
1194                         ret = ulist_add(tmp, glist->group->qgroupid,
1195                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
1196                         if (ret < 0)
1197                                 goto out;
1198                 }
1199         }
1200         ret = 0;
1201 out:
1202         return ret;
1203 }
1204 
1205 
1206 /*
1207  * Quick path for updating qgroup with only excl refs.
1208  *
1209  * In that case, just update all parent will be enough.
1210  * Or we needs to do a full rescan.
1211  * Caller should also hold fs_info->qgroup_lock.
1212  *
1213  * Return 0 for quick update, return >0 for need to full rescan
1214  * and mark INCONSISTENT flag.
1215  * Return < 0 for other error.
1216  */
1217 static int quick_update_accounting(struct btrfs_fs_info *fs_info,
1218                                    struct ulist *tmp, u64 src, u64 dst,
1219                                    int sign)
1220 {
1221         struct btrfs_qgroup *qgroup;
1222         int ret = 1;
1223         int err = 0;
1224 
1225         qgroup = find_qgroup_rb(fs_info, src);
1226         if (!qgroup)
1227                 goto out;
1228         if (qgroup->excl == qgroup->rfer) {
1229                 ret = 0;
1230                 err = __qgroup_excl_accounting(fs_info, tmp, dst,
1231                                                qgroup, sign);
1232                 if (err < 0) {
1233                         ret = err;
1234                         goto out;
1235                 }
1236         }
1237 out:
1238         if (ret)
1239                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1240         return ret;
1241 }
1242 
1243 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1244                               u64 dst)
1245 {
1246         struct btrfs_fs_info *fs_info = trans->fs_info;
1247         struct btrfs_root *quota_root;
1248         struct btrfs_qgroup *parent;
1249         struct btrfs_qgroup *member;
1250         struct btrfs_qgroup_list *list;
1251         struct ulist *tmp;
1252         int ret = 0;
1253 
1254         /* Check the level of src and dst first */
1255         if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
1256                 return -EINVAL;
1257 
1258         tmp = ulist_alloc(GFP_KERNEL);
1259         if (!tmp)
1260                 return -ENOMEM;
1261 
1262         mutex_lock(&fs_info->qgroup_ioctl_lock);
1263         quota_root = fs_info->quota_root;
1264         if (!quota_root) {
1265                 ret = -EINVAL;
1266                 goto out;
1267         }
1268         member = find_qgroup_rb(fs_info, src);
1269         parent = find_qgroup_rb(fs_info, dst);
1270         if (!member || !parent) {
1271                 ret = -EINVAL;
1272                 goto out;
1273         }
1274 
1275         /* check if such qgroup relation exist firstly */
1276         list_for_each_entry(list, &member->groups, next_group) {
1277                 if (list->group == parent) {
1278                         ret = -EEXIST;
1279                         goto out;
1280                 }
1281         }
1282 
1283         ret = add_qgroup_relation_item(trans, src, dst);
1284         if (ret)
1285                 goto out;
1286 
1287         ret = add_qgroup_relation_item(trans, dst, src);
1288         if (ret) {
1289                 del_qgroup_relation_item(trans, src, dst);
1290                 goto out;
1291         }
1292 
1293         spin_lock(&fs_info->qgroup_lock);
1294         ret = add_relation_rb(fs_info, src, dst);
1295         if (ret < 0) {
1296                 spin_unlock(&fs_info->qgroup_lock);
1297                 goto out;
1298         }
1299         ret = quick_update_accounting(fs_info, tmp, src, dst, 1);
1300         spin_unlock(&fs_info->qgroup_lock);
1301 out:
1302         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1303         ulist_free(tmp);
1304         return ret;
1305 }
1306 
1307 static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1308                                  u64 dst)
1309 {
1310         struct btrfs_fs_info *fs_info = trans->fs_info;
1311         struct btrfs_root *quota_root;
1312         struct btrfs_qgroup *parent;
1313         struct btrfs_qgroup *member;
1314         struct btrfs_qgroup_list *list;
1315         struct ulist *tmp;
1316         int ret = 0;
1317         int err;
1318 
1319         tmp = ulist_alloc(GFP_KERNEL);
1320         if (!tmp)
1321                 return -ENOMEM;
1322 
1323         quota_root = fs_info->quota_root;
1324         if (!quota_root) {
1325                 ret = -EINVAL;
1326                 goto out;
1327         }
1328 
1329         member = find_qgroup_rb(fs_info, src);
1330         parent = find_qgroup_rb(fs_info, dst);
1331         if (!member || !parent) {
1332                 ret = -EINVAL;
1333                 goto out;
1334         }
1335 
1336         /* check if such qgroup relation exist firstly */
1337         list_for_each_entry(list, &member->groups, next_group) {
1338                 if (list->group == parent)
1339                         goto exist;
1340         }
1341         ret = -ENOENT;
1342         goto out;
1343 exist:
1344         ret = del_qgroup_relation_item(trans, src, dst);
1345         err = del_qgroup_relation_item(trans, dst, src);
1346         if (err && !ret)
1347                 ret = err;
1348 
1349         spin_lock(&fs_info->qgroup_lock);
1350         del_relation_rb(fs_info, src, dst);
1351         ret = quick_update_accounting(fs_info, tmp, src, dst, -1);
1352         spin_unlock(&fs_info->qgroup_lock);
1353 out:
1354         ulist_free(tmp);
1355         return ret;
1356 }
1357 
1358 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1359                               u64 dst)
1360 {
1361         struct btrfs_fs_info *fs_info = trans->fs_info;
1362         int ret = 0;
1363 
1364         mutex_lock(&fs_info->qgroup_ioctl_lock);
1365         ret = __del_qgroup_relation(trans, src, dst);
1366         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1367 
1368         return ret;
1369 }
1370 
1371 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1372 {
1373         struct btrfs_fs_info *fs_info = trans->fs_info;
1374         struct btrfs_root *quota_root;
1375         struct btrfs_qgroup *qgroup;
1376         int ret = 0;
1377 
1378         mutex_lock(&fs_info->qgroup_ioctl_lock);
1379         quota_root = fs_info->quota_root;
1380         if (!quota_root) {
1381                 ret = -EINVAL;
1382                 goto out;
1383         }
1384         qgroup = find_qgroup_rb(fs_info, qgroupid);
1385         if (qgroup) {
1386                 ret = -EEXIST;
1387                 goto out;
1388         }
1389 
1390         ret = add_qgroup_item(trans, quota_root, qgroupid);
1391         if (ret)
1392                 goto out;
1393 
1394         spin_lock(&fs_info->qgroup_lock);
1395         qgroup = add_qgroup_rb(fs_info, qgroupid);
1396         spin_unlock(&fs_info->qgroup_lock);
1397 
1398         if (IS_ERR(qgroup))
1399                 ret = PTR_ERR(qgroup);
1400 out:
1401         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1402         return ret;
1403 }
1404 
1405 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1406 {
1407         struct btrfs_fs_info *fs_info = trans->fs_info;
1408         struct btrfs_root *quota_root;
1409         struct btrfs_qgroup *qgroup;
1410         struct btrfs_qgroup_list *list;
1411         int ret = 0;
1412 
1413         mutex_lock(&fs_info->qgroup_ioctl_lock);
1414         quota_root = fs_info->quota_root;
1415         if (!quota_root) {
1416                 ret = -EINVAL;
1417                 goto out;
1418         }
1419 
1420         qgroup = find_qgroup_rb(fs_info, qgroupid);
1421         if (!qgroup) {
1422                 ret = -ENOENT;
1423                 goto out;
1424         }
1425 
1426         /* Check if there are no children of this qgroup */
1427         if (!list_empty(&qgroup->members)) {
1428                 ret = -EBUSY;
1429                 goto out;
1430         }
1431 
1432         ret = del_qgroup_item(trans, qgroupid);
1433         if (ret && ret != -ENOENT)
1434                 goto out;
1435 
1436         while (!list_empty(&qgroup->groups)) {
1437                 list = list_first_entry(&qgroup->groups,
1438                                         struct btrfs_qgroup_list, next_group);
1439                 ret = __del_qgroup_relation(trans, qgroupid,
1440                                             list->group->qgroupid);
1441                 if (ret)
1442                         goto out;
1443         }
1444 
1445         spin_lock(&fs_info->qgroup_lock);
1446         del_qgroup_rb(fs_info, qgroupid);
1447         spin_unlock(&fs_info->qgroup_lock);
1448 out:
1449         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1450         return ret;
1451 }
1452 
1453 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
1454                        struct btrfs_qgroup_limit *limit)
1455 {
1456         struct btrfs_fs_info *fs_info = trans->fs_info;
1457         struct btrfs_root *quota_root;
1458         struct btrfs_qgroup *qgroup;
1459         int ret = 0;
1460         /* Sometimes we would want to clear the limit on this qgroup.
1461          * To meet this requirement, we treat the -1 as a special value
1462          * which tell kernel to clear the limit on this qgroup.
1463          */
1464         const u64 CLEAR_VALUE = -1;
1465 
1466         mutex_lock(&fs_info->qgroup_ioctl_lock);
1467         quota_root = fs_info->quota_root;
1468         if (!quota_root) {
1469                 ret = -EINVAL;
1470                 goto out;
1471         }
1472 
1473         qgroup = find_qgroup_rb(fs_info, qgroupid);
1474         if (!qgroup) {
1475                 ret = -ENOENT;
1476                 goto out;
1477         }
1478 
1479         spin_lock(&fs_info->qgroup_lock);
1480         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_RFER) {
1481                 if (limit->max_rfer == CLEAR_VALUE) {
1482                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1483                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1484                         qgroup->max_rfer = 0;
1485                 } else {
1486                         qgroup->max_rfer = limit->max_rfer;
1487                 }
1488         }
1489         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
1490                 if (limit->max_excl == CLEAR_VALUE) {
1491                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1492                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1493                         qgroup->max_excl = 0;
1494                 } else {
1495                         qgroup->max_excl = limit->max_excl;
1496                 }
1497         }
1498         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_RFER) {
1499                 if (limit->rsv_rfer == CLEAR_VALUE) {
1500                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1501                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1502                         qgroup->rsv_rfer = 0;
1503                 } else {
1504                         qgroup->rsv_rfer = limit->rsv_rfer;
1505                 }
1506         }
1507         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_EXCL) {
1508                 if (limit->rsv_excl == CLEAR_VALUE) {
1509                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1510                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1511                         qgroup->rsv_excl = 0;
1512                 } else {
1513                         qgroup->rsv_excl = limit->rsv_excl;
1514                 }
1515         }
1516         qgroup->lim_flags |= limit->flags;
1517 
1518         spin_unlock(&fs_info->qgroup_lock);
1519 
1520         ret = update_qgroup_limit_item(trans, qgroup);
1521         if (ret) {
1522                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1523                 btrfs_info(fs_info, "unable to update quota limit for %llu",
1524                        qgroupid);
1525         }
1526 
1527 out:
1528         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1529         return ret;
1530 }
1531 
1532 int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
1533                                 struct btrfs_delayed_ref_root *delayed_refs,
1534                                 struct btrfs_qgroup_extent_record *record)
1535 {
1536         struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
1537         struct rb_node *parent_node = NULL;
1538         struct btrfs_qgroup_extent_record *entry;
1539         u64 bytenr = record->bytenr;
1540 
1541         lockdep_assert_held(&delayed_refs->lock);
1542         trace_btrfs_qgroup_trace_extent(fs_info, record);
1543 
1544         while (*p) {
1545                 parent_node = *p;
1546                 entry = rb_entry(parent_node, struct btrfs_qgroup_extent_record,
1547                                  node);
1548                 if (bytenr < entry->bytenr) {
1549                         p = &(*p)->rb_left;
1550                 } else if (bytenr > entry->bytenr) {
1551                         p = &(*p)->rb_right;
1552                 } else {
1553                         if (record->data_rsv && !entry->data_rsv) {
1554                                 entry->data_rsv = record->data_rsv;
1555                                 entry->data_rsv_refroot =
1556                                         record->data_rsv_refroot;
1557                         }
1558                         return 1;
1559                 }
1560         }
1561 
1562         rb_link_node(&record->node, parent_node, p);
1563         rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
1564         return 0;
1565 }
1566 
1567 int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
1568                                    struct btrfs_qgroup_extent_record *qrecord)
1569 {
1570         struct ulist *old_root;
1571         u64 bytenr = qrecord->bytenr;
1572         int ret;
1573 
1574         ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false);
1575         if (ret < 0) {
1576                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1577                 btrfs_warn(fs_info,
1578 "error accounting new delayed refs extent (err code: %d), quota inconsistent",
1579                         ret);
1580                 return 0;
1581         }
1582 
1583         /*
1584          * Here we don't need to get the lock of
1585          * trans->transaction->delayed_refs, since inserted qrecord won't
1586          * be deleted, only qrecord->node may be modified (new qrecord insert)
1587          *
1588          * So modifying qrecord->old_roots is safe here
1589          */
1590         qrecord->old_roots = old_root;
1591         return 0;
1592 }
1593 
1594 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
1595                               u64 num_bytes, gfp_t gfp_flag)
1596 {
1597         struct btrfs_fs_info *fs_info = trans->fs_info;
1598         struct btrfs_qgroup_extent_record *record;
1599         struct btrfs_delayed_ref_root *delayed_refs;
1600         int ret;
1601 
1602         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)
1603             || bytenr == 0 || num_bytes == 0)
1604                 return 0;
1605         record = kzalloc(sizeof(*record), gfp_flag);
1606         if (!record)
1607                 return -ENOMEM;
1608 
1609         delayed_refs = &trans->transaction->delayed_refs;
1610         record->bytenr = bytenr;
1611         record->num_bytes = num_bytes;
1612         record->old_roots = NULL;
1613 
1614         spin_lock(&delayed_refs->lock);
1615         ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record);
1616         spin_unlock(&delayed_refs->lock);
1617         if (ret > 0) {
1618                 kfree(record);
1619                 return 0;
1620         }
1621         return btrfs_qgroup_trace_extent_post(fs_info, record);
1622 }
1623 
1624 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
1625                                   struct extent_buffer *eb)
1626 {
1627         struct btrfs_fs_info *fs_info = trans->fs_info;
1628         int nr = btrfs_header_nritems(eb);
1629         int i, extent_type, ret;
1630         struct btrfs_key key;
1631         struct btrfs_file_extent_item *fi;
1632         u64 bytenr, num_bytes;
1633 
1634         /* We can be called directly from walk_up_proc() */
1635         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1636                 return 0;
1637 
1638         for (i = 0; i < nr; i++) {
1639                 btrfs_item_key_to_cpu(eb, &key, i);
1640 
1641                 if (key.type != BTRFS_EXTENT_DATA_KEY)
1642                         continue;
1643 
1644                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
1645                 /* filter out non qgroup-accountable extents  */
1646                 extent_type = btrfs_file_extent_type(eb, fi);
1647 
1648                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
1649                         continue;
1650 
1651                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
1652                 if (!bytenr)
1653                         continue;
1654 
1655                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
1656 
1657                 ret = btrfs_qgroup_trace_extent(trans, bytenr, num_bytes,
1658                                                 GFP_NOFS);
1659                 if (ret)
1660                         return ret;
1661         }
1662         cond_resched();
1663         return 0;
1664 }
1665 
1666 /*
1667  * Walk up the tree from the bottom, freeing leaves and any interior
1668  * nodes which have had all slots visited. If a node (leaf or
1669  * interior) is freed, the node above it will have it's slot
1670  * incremented. The root node will never be freed.
1671  *
1672  * At the end of this function, we should have a path which has all
1673  * slots incremented to the next position for a search. If we need to
1674  * read a new node it will be NULL and the node above it will have the
1675  * correct slot selected for a later read.
1676  *
1677  * If we increment the root nodes slot counter past the number of
1678  * elements, 1 is returned to signal completion of the search.
1679  */
1680 static int adjust_slots_upwards(struct btrfs_path *path, int root_level)
1681 {
1682         int level = 0;
1683         int nr, slot;
1684         struct extent_buffer *eb;
1685 
1686         if (root_level == 0)
1687                 return 1;
1688 
1689         while (level <= root_level) {
1690                 eb = path->nodes[level];
1691                 nr = btrfs_header_nritems(eb);
1692                 path->slots[level]++;
1693                 slot = path->slots[level];
1694                 if (slot >= nr || level == 0) {
1695                         /*
1696                          * Don't free the root -  we will detect this
1697                          * condition after our loop and return a
1698                          * positive value for caller to stop walking the tree.
1699                          */
1700                         if (level != root_level) {
1701                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
1702                                 path->locks[level] = 0;
1703 
1704                                 free_extent_buffer(eb);
1705                                 path->nodes[level] = NULL;
1706                                 path->slots[level] = 0;
1707                         }
1708                 } else {
1709                         /*
1710                          * We have a valid slot to walk back down
1711                          * from. Stop here so caller can process these
1712                          * new nodes.
1713                          */
1714                         break;
1715                 }
1716 
1717                 level++;
1718         }
1719 
1720         eb = path->nodes[root_level];
1721         if (path->slots[root_level] >= btrfs_header_nritems(eb))
1722                 return 1;
1723 
1724         return 0;
1725 }
1726 
1727 /*
1728  * Helper function to trace a subtree tree block swap.
1729  *
1730  * The swap will happen in highest tree block, but there may be a lot of
1731  * tree blocks involved.
1732  *
1733  * For example:
1734  *  OO = Old tree blocks
1735  *  NN = New tree blocks allocated during balance
1736  *
1737  *           File tree (257)                  Reloc tree for 257
1738  * L2              OO                                NN
1739  *               /    \                            /    \
1740  * L1          OO      OO (a)                    OO      NN (a)
1741  *            / \     / \                       / \     / \
1742  * L0       OO   OO OO   OO                   OO   OO NN   NN
1743  *                  (b)  (c)                          (b)  (c)
1744  *
1745  * When calling qgroup_trace_extent_swap(), we will pass:
1746  * @src_eb = OO(a)
1747  * @dst_path = [ nodes[1] = NN(a), nodes[0] = NN(c) ]
1748  * @dst_level = 0
1749  * @root_level = 1
1750  *
1751  * In that case, qgroup_trace_extent_swap() will search from OO(a) to
1752  * reach OO(c), then mark both OO(c) and NN(c) as qgroup dirty.
1753  *
1754  * The main work of qgroup_trace_extent_swap() can be split into 3 parts:
1755  *
1756  * 1) Tree search from @src_eb
1757  *    It should acts as a simplified btrfs_search_slot().
1758  *    The key for search can be extracted from @dst_path->nodes[dst_level]
1759  *    (first key).
1760  *
1761  * 2) Mark the final tree blocks in @src_path and @dst_path qgroup dirty
1762  *    NOTE: In above case, OO(a) and NN(a) won't be marked qgroup dirty.
1763  *    They should be marked during previous (@dst_level = 1) iteration.
1764  *
1765  * 3) Mark file extents in leaves dirty
1766  *    We don't have good way to pick out new file extents only.
1767  *    So we still follow the old method by scanning all file extents in
1768  *    the leave.
1769  *
1770  * This function can free us from keeping two paths, thus later we only need
1771  * to care about how to iterate all new tree blocks in reloc tree.
1772  */
1773 static int qgroup_trace_extent_swap(struct btrfs_trans_handle* trans,
1774                                     struct extent_buffer *src_eb,
1775                                     struct btrfs_path *dst_path,
1776                                     int dst_level, int root_level,
1777                                     bool trace_leaf)
1778 {
1779         struct btrfs_key key;
1780         struct btrfs_path *src_path;
1781         struct btrfs_fs_info *fs_info = trans->fs_info;
1782         u32 nodesize = fs_info->nodesize;
1783         int cur_level = root_level;
1784         int ret;
1785 
1786         BUG_ON(dst_level > root_level);
1787         /* Level mismatch */
1788         if (btrfs_header_level(src_eb) != root_level)
1789                 return -EINVAL;
1790 
1791         src_path = btrfs_alloc_path();
1792         if (!src_path) {
1793                 ret = -ENOMEM;
1794                 goto out;
1795         }
1796 
1797         if (dst_level)
1798                 btrfs_node_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
1799         else
1800                 btrfs_item_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
1801 
1802         /* For src_path */
1803         extent_buffer_get(src_eb);
1804         src_path->nodes[root_level] = src_eb;
1805         src_path->slots[root_level] = dst_path->slots[root_level];
1806         src_path->locks[root_level] = 0;
1807 
1808         /* A simplified version of btrfs_search_slot() */
1809         while (cur_level >= dst_level) {
1810                 struct btrfs_key src_key;
1811                 struct btrfs_key dst_key;
1812 
1813                 if (src_path->nodes[cur_level] == NULL) {
1814                         struct btrfs_key first_key;
1815                         struct extent_buffer *eb;
1816                         int parent_slot;
1817                         u64 child_gen;
1818                         u64 child_bytenr;
1819 
1820                         eb = src_path->nodes[cur_level + 1];
1821                         parent_slot = src_path->slots[cur_level + 1];
1822                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
1823                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
1824                         btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
1825 
1826                         eb = read_tree_block(fs_info, child_bytenr, child_gen,
1827                                              cur_level, &first_key);
1828                         if (IS_ERR(eb)) {
1829                                 ret = PTR_ERR(eb);
1830                                 goto out;
1831                         } else if (!extent_buffer_uptodate(eb)) {
1832                                 free_extent_buffer(eb);
1833                                 ret = -EIO;
1834                                 goto out;
1835                         }
1836 
1837                         src_path->nodes[cur_level] = eb;
1838 
1839                         btrfs_tree_read_lock(eb);
1840                         btrfs_set_lock_blocking_read(eb);
1841                         src_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
1842                 }
1843 
1844                 src_path->slots[cur_level] = dst_path->slots[cur_level];
1845                 if (cur_level) {
1846                         btrfs_node_key_to_cpu(dst_path->nodes[cur_level],
1847                                         &dst_key, dst_path->slots[cur_level]);
1848                         btrfs_node_key_to_cpu(src_path->nodes[cur_level],
1849                                         &src_key, src_path->slots[cur_level]);
1850                 } else {
1851                         btrfs_item_key_to_cpu(dst_path->nodes[cur_level],
1852                                         &dst_key, dst_path->slots[cur_level]);
1853                         btrfs_item_key_to_cpu(src_path->nodes[cur_level],
1854                                         &src_key, src_path->slots[cur_level]);
1855                 }
1856                 /* Content mismatch, something went wrong */
1857                 if (btrfs_comp_cpu_keys(&dst_key, &src_key)) {
1858                         ret = -ENOENT;
1859                         goto out;
1860                 }
1861                 cur_level--;
1862         }
1863 
1864         /*
1865          * Now both @dst_path and @src_path have been populated, record the tree
1866          * blocks for qgroup accounting.
1867          */
1868         ret = btrfs_qgroup_trace_extent(trans, src_path->nodes[dst_level]->start,
1869                         nodesize, GFP_NOFS);
1870         if (ret < 0)
1871                 goto out;
1872         ret = btrfs_qgroup_trace_extent(trans,
1873                         dst_path->nodes[dst_level]->start,
1874                         nodesize, GFP_NOFS);
1875         if (ret < 0)
1876                 goto out;
1877 
1878         /* Record leaf file extents */
1879         if (dst_level == 0 && trace_leaf) {
1880                 ret = btrfs_qgroup_trace_leaf_items(trans, src_path->nodes[0]);
1881                 if (ret < 0)
1882                         goto out;
1883                 ret = btrfs_qgroup_trace_leaf_items(trans, dst_path->nodes[0]);
1884         }
1885 out:
1886         btrfs_free_path(src_path);
1887         return ret;
1888 }
1889 
1890 /*
1891  * Helper function to do recursive generation-aware depth-first search, to
1892  * locate all new tree blocks in a subtree of reloc tree.
1893  *
1894  * E.g. (OO = Old tree blocks, NN = New tree blocks, whose gen == last_snapshot)
1895  *         reloc tree
1896  * L2         NN (a)
1897  *          /    \
1898  * L1    OO        NN (b)
1899  *      /  \      /  \
1900  * L0  OO  OO    OO  NN
1901  *               (c) (d)
1902  * If we pass:
1903  * @dst_path = [ nodes[1] = NN(b), nodes[0] = NULL ],
1904  * @cur_level = 1
1905  * @root_level = 1
1906  *
1907  * We will iterate through tree blocks NN(b), NN(d) and info qgroup to trace
1908  * above tree blocks along with their counter parts in file tree.
1909  * While during search, old tree blocks OO(c) will be skipped as tree block swap
1910  * won't affect OO(c).
1911  */
1912 static int qgroup_trace_new_subtree_blocks(struct btrfs_trans_handle* trans,
1913                                            struct extent_buffer *src_eb,
1914                                            struct btrfs_path *dst_path,
1915                                            int cur_level, int root_level,
1916                                            u64 last_snapshot, bool trace_leaf)
1917 {
1918         struct btrfs_fs_info *fs_info = trans->fs_info;
1919         struct extent_buffer *eb;
1920         bool need_cleanup = false;
1921         int ret = 0;
1922         int i;
1923 
1924         /* Level sanity check */
1925         if (cur_level < 0 || cur_level >= BTRFS_MAX_LEVEL - 1 ||
1926             root_level < 0 || root_level >= BTRFS_MAX_LEVEL - 1 ||
1927             root_level < cur_level) {
1928                 btrfs_err_rl(fs_info,
1929                         "%s: bad levels, cur_level=%d root_level=%d",
1930                         __func__, cur_level, root_level);
1931                 return -EUCLEAN;
1932         }
1933 
1934         /* Read the tree block if needed */
1935         if (dst_path->nodes[cur_level] == NULL) {
1936                 struct btrfs_key first_key;
1937                 int parent_slot;
1938                 u64 child_gen;
1939                 u64 child_bytenr;
1940 
1941                 /*
1942                  * dst_path->nodes[root_level] must be initialized before
1943                  * calling this function.
1944                  */
1945                 if (cur_level == root_level) {
1946                         btrfs_err_rl(fs_info,
1947         "%s: dst_path->nodes[%d] not initialized, root_level=%d cur_level=%d",
1948                                 __func__, root_level, root_level, cur_level);
1949                         return -EUCLEAN;
1950                 }
1951 
1952                 /*
1953                  * We need to get child blockptr/gen from parent before we can
1954                  * read it.
1955                   */
1956                 eb = dst_path->nodes[cur_level + 1];
1957                 parent_slot = dst_path->slots[cur_level + 1];
1958                 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
1959                 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
1960                 btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
1961 
1962                 /* This node is old, no need to trace */
1963                 if (child_gen < last_snapshot)
1964                         goto out;
1965 
1966                 eb = read_tree_block(fs_info, child_bytenr, child_gen,
1967                                      cur_level, &first_key);
1968                 if (IS_ERR(eb)) {
1969                         ret = PTR_ERR(eb);
1970                         goto out;
1971                 } else if (!extent_buffer_uptodate(eb)) {
1972                         free_extent_buffer(eb);
1973                         ret = -EIO;
1974                         goto out;
1975                 }
1976 
1977                 dst_path->nodes[cur_level] = eb;
1978                 dst_path->slots[cur_level] = 0;
1979 
1980                 btrfs_tree_read_lock(eb);
1981                 btrfs_set_lock_blocking_read(eb);
1982                 dst_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
1983                 need_cleanup = true;
1984         }
1985 
1986         /* Now record this tree block and its counter part for qgroups */
1987         ret = qgroup_trace_extent_swap(trans, src_eb, dst_path, cur_level,
1988                                        root_level, trace_leaf);
1989         if (ret < 0)
1990                 goto cleanup;
1991 
1992         eb = dst_path->nodes[cur_level];
1993 
1994         if (cur_level > 0) {
1995                 /* Iterate all child tree blocks */
1996                 for (i = 0; i < btrfs_header_nritems(eb); i++) {
1997                         /* Skip old tree blocks as they won't be swapped */
1998                         if (btrfs_node_ptr_generation(eb, i) < last_snapshot)
1999                                 continue;
2000                         dst_path->slots[cur_level] = i;
2001 
2002                         /* Recursive call (at most 7 times) */
2003                         ret = qgroup_trace_new_subtree_blocks(trans, src_eb,
2004                                         dst_path, cur_level - 1, root_level,
2005                                         last_snapshot, trace_leaf);
2006                         if (ret < 0)
2007                                 goto cleanup;
2008                 }
2009         }
2010 
2011 cleanup:
2012         if (need_cleanup) {
2013                 /* Clean up */
2014                 btrfs_tree_unlock_rw(dst_path->nodes[cur_level],
2015                                      dst_path->locks[cur_level]);
2016                 free_extent_buffer(dst_path->nodes[cur_level]);
2017                 dst_path->nodes[cur_level] = NULL;
2018                 dst_path->slots[cur_level] = 0;
2019                 dst_path->locks[cur_level] = 0;
2020         }
2021 out:
2022         return ret;
2023 }
2024 
2025 static int qgroup_trace_subtree_swap(struct btrfs_trans_handle *trans,
2026                                 struct extent_buffer *src_eb,
2027                                 struct extent_buffer *dst_eb,
2028                                 u64 last_snapshot, bool trace_leaf)
2029 {
2030         struct btrfs_fs_info *fs_info = trans->fs_info;
2031         struct btrfs_path *dst_path = NULL;
2032         int level;
2033         int ret;
2034 
2035         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2036                 return 0;
2037 
2038         /* Wrong parameter order */
2039         if (btrfs_header_generation(src_eb) > btrfs_header_generation(dst_eb)) {
2040                 btrfs_err_rl(fs_info,
2041                 "%s: bad parameter order, src_gen=%llu dst_gen=%llu", __func__,
2042                              btrfs_header_generation(src_eb),
2043                              btrfs_header_generation(dst_eb));
2044                 return -EUCLEAN;
2045         }
2046 
2047         if (!extent_buffer_uptodate(src_eb) || !extent_buffer_uptodate(dst_eb)) {
2048                 ret = -EIO;
2049                 goto out;
2050         }
2051 
2052         level = btrfs_header_level(dst_eb);
2053         dst_path = btrfs_alloc_path();
2054         if (!dst_path) {
2055                 ret = -ENOMEM;
2056                 goto out;
2057         }
2058         /* For dst_path */
2059         extent_buffer_get(dst_eb);
2060         dst_path->nodes[level] = dst_eb;
2061         dst_path->slots[level] = 0;
2062         dst_path->locks[level] = 0;
2063 
2064         /* Do the generation aware breadth-first search */
2065         ret = qgroup_trace_new_subtree_blocks(trans, src_eb, dst_path, level,
2066                                               level, last_snapshot, trace_leaf);
2067         if (ret < 0)
2068                 goto out;
2069         ret = 0;
2070 
2071 out:
2072         btrfs_free_path(dst_path);
2073         if (ret < 0)
2074                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2075         return ret;
2076 }
2077 
2078 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
2079                                struct extent_buffer *root_eb,
2080                                u64 root_gen, int root_level)
2081 {
2082         struct btrfs_fs_info *fs_info = trans->fs_info;
2083         int ret = 0;
2084         int level;
2085         struct extent_buffer *eb = root_eb;
2086         struct btrfs_path *path = NULL;
2087 
2088         BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
2089         BUG_ON(root_eb == NULL);
2090 
2091         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2092                 return 0;
2093 
2094         if (!extent_buffer_uptodate(root_eb)) {
2095                 ret = btrfs_read_buffer(root_eb, root_gen, root_level, NULL);
2096                 if (ret)
2097                         goto out;
2098         }
2099 
2100         if (root_level == 0) {
2101                 ret = btrfs_qgroup_trace_leaf_items(trans, root_eb);
2102                 goto out;
2103         }
2104 
2105         path = btrfs_alloc_path();
2106         if (!path)
2107                 return -ENOMEM;
2108 
2109         /*
2110          * Walk down the tree.  Missing extent blocks are filled in as
2111          * we go. Metadata is accounted every time we read a new
2112          * extent block.
2113          *
2114          * When we reach a leaf, we account for file extent items in it,
2115          * walk back up the tree (adjusting slot pointers as we go)
2116          * and restart the search process.
2117          */
2118         extent_buffer_get(root_eb); /* For path */
2119         path->nodes[root_level] = root_eb;
2120         path->slots[root_level] = 0;
2121         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
2122 walk_down:
2123         level = root_level;
2124         while (level >= 0) {
2125                 if (path->nodes[level] == NULL) {
2126                         struct btrfs_key first_key;
2127                         int parent_slot;
2128                         u64 child_gen;
2129                         u64 child_bytenr;
2130 
2131                         /*
2132                          * We need to get child blockptr/gen from parent before
2133                          * we can read it.
2134                           */
2135                         eb = path->nodes[level + 1];
2136                         parent_slot = path->slots[level + 1];
2137                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
2138                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
2139                         btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
2140 
2141                         eb = read_tree_block(fs_info, child_bytenr, child_gen,
2142                                              level, &first_key);
2143                         if (IS_ERR(eb)) {
2144                                 ret = PTR_ERR(eb);
2145                                 goto out;
2146                         } else if (!extent_buffer_uptodate(eb)) {
2147                                 free_extent_buffer(eb);
2148                                 ret = -EIO;
2149                                 goto out;
2150                         }
2151 
2152                         path->nodes[level] = eb;
2153                         path->slots[level] = 0;
2154 
2155                         btrfs_tree_read_lock(eb);
2156                         btrfs_set_lock_blocking_read(eb);
2157                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
2158 
2159                         ret = btrfs_qgroup_trace_extent(trans, child_bytenr,
2160                                                         fs_info->nodesize,
2161                                                         GFP_NOFS);
2162                         if (ret)
2163                                 goto out;
2164                 }
2165 
2166                 if (level == 0) {
2167                         ret = btrfs_qgroup_trace_leaf_items(trans,
2168                                                             path->nodes[level]);
2169                         if (ret)
2170                                 goto out;
2171 
2172                         /* Nonzero return here means we completed our search */
2173                         ret = adjust_slots_upwards(path, root_level);
2174                         if (ret)
2175                                 break;
2176 
2177                         /* Restart search with new slots */
2178                         goto walk_down;
2179                 }
2180 
2181                 level--;
2182         }
2183 
2184         ret = 0;
2185 out:
2186         btrfs_free_path(path);
2187 
2188         return ret;
2189 }
2190 
2191 #define UPDATE_NEW      0
2192 #define UPDATE_OLD      1
2193 /*
2194  * Walk all of the roots that points to the bytenr and adjust their refcnts.
2195  */
2196 static int qgroup_update_refcnt(struct btrfs_fs_info *fs_info,
2197                                 struct ulist *roots, struct ulist *tmp,
2198                                 struct ulist *qgroups, u64 seq, int update_old)
2199 {
2200         struct ulist_node *unode;
2201         struct ulist_iterator uiter;
2202         struct ulist_node *tmp_unode;
2203         struct ulist_iterator tmp_uiter;
2204         struct btrfs_qgroup *qg;
2205         int ret = 0;
2206 
2207         if (!roots)
2208                 return 0;
2209         ULIST_ITER_INIT(&uiter);
2210         while ((unode = ulist_next(roots, &uiter))) {
2211                 qg = find_qgroup_rb(fs_info, unode->val);
2212                 if (!qg)
2213                         continue;
2214 
2215                 ulist_reinit(tmp);
2216                 ret = ulist_add(qgroups, qg->qgroupid, qgroup_to_aux(qg),
2217                                 GFP_ATOMIC);
2218                 if (ret < 0)
2219                         return ret;
2220                 ret = ulist_add(tmp, qg->qgroupid, qgroup_to_aux(qg), GFP_ATOMIC);
2221                 if (ret < 0)
2222                         return ret;
2223                 ULIST_ITER_INIT(&tmp_uiter);
2224                 while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
2225                         struct btrfs_qgroup_list *glist;
2226 
2227                         qg = unode_aux_to_qgroup(tmp_unode);
2228                         if (update_old)
2229                                 btrfs_qgroup_update_old_refcnt(qg, seq, 1);
2230                         else
2231                                 btrfs_qgroup_update_new_refcnt(qg, seq, 1);
2232                         list_for_each_entry(glist, &qg->groups, next_group) {
2233                                 ret = ulist_add(qgroups, glist->group->qgroupid,
2234                                                 qgroup_to_aux(glist->group),
2235                                                 GFP_ATOMIC);
2236                                 if (ret < 0)
2237                                         return ret;
2238                                 ret = ulist_add(tmp, glist->group->qgroupid,
2239                                                 qgroup_to_aux(glist->group),
2240                                                 GFP_ATOMIC);
2241                                 if (ret < 0)
2242                                         return ret;
2243                         }
2244                 }
2245         }
2246         return 0;
2247 }
2248 
2249 /*
2250  * Update qgroup rfer/excl counters.
2251  * Rfer update is easy, codes can explain themselves.
2252  *
2253  * Excl update is tricky, the update is split into 2 part.
2254  * Part 1: Possible exclusive <-> sharing detect:
2255  *      |       A       |       !A      |
2256  *  -------------------------------------
2257  *  B   |       *       |       -       |
2258  *  -------------------------------------
2259  *  !B  |       +       |       **      |
2260  *  -------------------------------------
2261  *
2262  * Conditions:
2263  * A:   cur_old_roots < nr_old_roots    (not exclusive before)
2264  * !A:  cur_old_roots == nr_old_roots   (possible exclusive before)
2265  * B:   cur_new_roots < nr_new_roots    (not exclusive now)
2266  * !B:  cur_new_roots == nr_new_roots   (possible exclusive now)
2267  *
2268  * Results:
2269  * +: Possible sharing -> exclusive     -: Possible exclusive -> sharing
2270  * *: Definitely not changed.           **: Possible unchanged.
2271  *
2272  * For !A and !B condition, the exception is cur_old/new_roots == 0 case.
2273  *
2274  * To make the logic clear, we first use condition A and B to split
2275  * combination into 4 results.
2276  *
2277  * Then, for result "+" and "-", check old/new_roots == 0 case, as in them
2278  * only on variant maybe 0.
2279  *
2280  * Lastly, check result **, since there are 2 variants maybe 0, split them
2281  * again(2x2).
2282  * But this time we don't need to consider other things, the codes and logic
2283  * is easy to understand now.
2284  */
2285 static int qgroup_update_counters(struct btrfs_fs_info *fs_info,
2286                                   struct ulist *qgroups,
2287                                   u64 nr_old_roots,
2288                                   u64 nr_new_roots,
2289                                   u64 num_bytes, u64 seq)
2290 {
2291         struct ulist_node *unode;
2292         struct ulist_iterator uiter;
2293         struct btrfs_qgroup *qg;
2294         u64 cur_new_count, cur_old_count;
2295 
2296         ULIST_ITER_INIT(&uiter);
2297         while ((unode = ulist_next(qgroups, &uiter))) {
2298                 bool dirty = false;
2299 
2300                 qg = unode_aux_to_qgroup(unode);
2301                 cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
2302                 cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
2303 
2304                 trace_qgroup_update_counters(fs_info, qg, cur_old_count,
2305                                              cur_new_count);
2306 
2307                 /* Rfer update part */
2308                 if (cur_old_count == 0 && cur_new_count > 0) {
2309                         qg->rfer += num_bytes;
2310                         qg->rfer_cmpr += num_bytes;
2311                         dirty = true;
2312                 }
2313                 if (cur_old_count > 0 && cur_new_count == 0) {
2314                         qg->rfer -= num_bytes;
2315                         qg->rfer_cmpr -= num_bytes;
2316                         dirty = true;
2317                 }
2318 
2319                 /* Excl update part */
2320                 /* Exclusive/none -> shared case */
2321                 if (cur_old_count == nr_old_roots &&
2322                     cur_new_count < nr_new_roots) {
2323                         /* Exclusive -> shared */
2324                         if (cur_old_count != 0) {
2325                                 qg->excl -= num_bytes;
2326                                 qg->excl_cmpr -= num_bytes;
2327                                 dirty = true;
2328                         }
2329                 }
2330 
2331                 /* Shared -> exclusive/none case */
2332                 if (cur_old_count < nr_old_roots &&
2333                     cur_new_count == nr_new_roots) {
2334                         /* Shared->exclusive */
2335                         if (cur_new_count != 0) {
2336                                 qg->excl += num_bytes;
2337                                 qg->excl_cmpr += num_bytes;
2338                                 dirty = true;
2339                         }
2340                 }
2341 
2342                 /* Exclusive/none -> exclusive/none case */
2343                 if (cur_old_count == nr_old_roots &&
2344                     cur_new_count == nr_new_roots) {
2345                         if (cur_old_count == 0) {
2346                                 /* None -> exclusive/none */
2347 
2348                                 if (cur_new_count != 0) {
2349                                         /* None -> exclusive */
2350                                         qg->excl += num_bytes;
2351                                         qg->excl_cmpr += num_bytes;
2352                                         dirty = true;
2353                                 }
2354                                 /* None -> none, nothing changed */
2355                         } else {
2356                                 /* Exclusive -> exclusive/none */
2357 
2358                                 if (cur_new_count == 0) {
2359                                         /* Exclusive -> none */
2360                                         qg->excl -= num_bytes;
2361                                         qg->excl_cmpr -= num_bytes;
2362                                         dirty = true;
2363                                 }
2364                                 /* Exclusive -> exclusive, nothing changed */
2365                         }
2366                 }
2367 
2368                 if (dirty)
2369                         qgroup_dirty(fs_info, qg);
2370         }
2371         return 0;
2372 }
2373 
2374 /*
2375  * Check if the @roots potentially is a list of fs tree roots
2376  *
2377  * Return 0 for definitely not a fs/subvol tree roots ulist
2378  * Return 1 for possible fs/subvol tree roots in the list (considering an empty
2379  *          one as well)
2380  */
2381 static int maybe_fs_roots(struct ulist *roots)
2382 {
2383         struct ulist_node *unode;
2384         struct ulist_iterator uiter;
2385 
2386         /* Empty one, still possible for fs roots */
2387         if (!roots || roots->nnodes == 0)
2388                 return 1;
2389 
2390         ULIST_ITER_INIT(&uiter);
2391         unode = ulist_next(roots, &uiter);
2392         if (!unode)
2393                 return 1;
2394 
2395         /*
2396          * If it contains fs tree roots, then it must belong to fs/subvol
2397          * trees.
2398          * If it contains a non-fs tree, it won't be shared with fs/subvol trees.
2399          */
2400         return is_fstree(unode->val);
2401 }
2402 
2403 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
2404                                 u64 num_bytes, struct ulist *old_roots,
2405                                 struct ulist *new_roots)
2406 {
2407         struct btrfs_fs_info *fs_info = trans->fs_info;
2408         struct ulist *qgroups = NULL;
2409         struct ulist *tmp = NULL;
2410         u64 seq;
2411         u64 nr_new_roots = 0;
2412         u64 nr_old_roots = 0;
2413         int ret = 0;
2414 
2415         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2416                 return 0;
2417 
2418         if (new_roots) {
2419                 if (!maybe_fs_roots(new_roots))
2420                         goto out_free;
2421                 nr_new_roots = new_roots->nnodes;
2422         }
2423         if (old_roots) {
2424                 if (!maybe_fs_roots(old_roots))
2425                         goto out_free;
2426                 nr_old_roots = old_roots->nnodes;
2427         }
2428 
2429         /* Quick exit, either not fs tree roots, or won't affect any qgroup */
2430         if (nr_old_roots == 0 && nr_new_roots == 0)
2431                 goto out_free;
2432 
2433         BUG_ON(!fs_info->quota_root);
2434 
2435         trace_btrfs_qgroup_account_extent(fs_info, trans->transid, bytenr,
2436                                         num_bytes, nr_old_roots, nr_new_roots);
2437 
2438         qgroups = ulist_alloc(GFP_NOFS);
2439         if (!qgroups) {
2440                 ret = -ENOMEM;
2441                 goto out_free;
2442         }
2443         tmp = ulist_alloc(GFP_NOFS);
2444         if (!tmp) {
2445                 ret = -ENOMEM;
2446                 goto out_free;
2447         }
2448 
2449         mutex_lock(&fs_info->qgroup_rescan_lock);
2450         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
2451                 if (fs_info->qgroup_rescan_progress.objectid <= bytenr) {
2452                         mutex_unlock(&fs_info->qgroup_rescan_lock);
2453                         ret = 0;
2454                         goto out_free;
2455                 }
2456         }
2457         mutex_unlock(&fs_info->qgroup_rescan_lock);
2458 
2459         spin_lock(&fs_info->qgroup_lock);
2460         seq = fs_info->qgroup_seq;
2461 
2462         /* Update old refcnts using old_roots */
2463         ret = qgroup_update_refcnt(fs_info, old_roots, tmp, qgroups, seq,
2464                                    UPDATE_OLD);
2465         if (ret < 0)
2466                 goto out;
2467 
2468         /* Update new refcnts using new_roots */
2469         ret = qgroup_update_refcnt(fs_info, new_roots, tmp, qgroups, seq,
2470                                    UPDATE_NEW);
2471         if (ret < 0)
2472                 goto out;
2473 
2474         qgroup_update_counters(fs_info, qgroups, nr_old_roots, nr_new_roots,
2475                                num_bytes, seq);
2476 
2477         /*
2478          * Bump qgroup_seq to avoid seq overlap
2479          */
2480         fs_info->qgroup_seq += max(nr_old_roots, nr_new_roots) + 1;
2481 out:
2482         spin_unlock(&fs_info->qgroup_lock);
2483 out_free:
2484         ulist_free(tmp);
2485         ulist_free(qgroups);
2486         ulist_free(old_roots);
2487         ulist_free(new_roots);
2488         return ret;
2489 }
2490 
2491 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
2492 {
2493         struct btrfs_fs_info *fs_info = trans->fs_info;
2494         struct btrfs_qgroup_extent_record *record;
2495         struct btrfs_delayed_ref_root *delayed_refs;
2496         struct ulist *new_roots = NULL;
2497         struct rb_node *node;
2498         u64 num_dirty_extents = 0;
2499         u64 qgroup_to_skip;
2500         int ret = 0;
2501 
2502         delayed_refs = &trans->transaction->delayed_refs;
2503         qgroup_to_skip = delayed_refs->qgroup_to_skip;
2504         while ((node = rb_first(&delayed_refs->dirty_extent_root))) {
2505                 record = rb_entry(node, struct btrfs_qgroup_extent_record,
2506                                   node);
2507 
2508                 num_dirty_extents++;
2509                 trace_btrfs_qgroup_account_extents(fs_info, record);
2510 
2511                 if (!ret) {
2512                         /*
2513                          * Old roots should be searched when inserting qgroup
2514                          * extent record
2515                          */
2516                         if (WARN_ON(!record->old_roots)) {
2517                                 /* Search commit root to find old_roots */
2518                                 ret = btrfs_find_all_roots(NULL, fs_info,
2519                                                 record->bytenr, 0,
2520                                                 &record->old_roots, false);
2521                                 if (ret < 0)
2522                                         goto cleanup;
2523                         }
2524 
2525                         /* Free the reserved data space */
2526                         btrfs_qgroup_free_refroot(fs_info,
2527                                         record->data_rsv_refroot,
2528                                         record->data_rsv,
2529                                         BTRFS_QGROUP_RSV_DATA);
2530                         /*
2531                          * Use SEQ_LAST as time_seq to do special search, which
2532                          * doesn't lock tree or delayed_refs and search current
2533                          * root. It's safe inside commit_transaction().
2534                          */
2535                         ret = btrfs_find_all_roots(trans, fs_info,
2536                                 record->bytenr, SEQ_LAST, &new_roots, false);
2537                         if (ret < 0)
2538                                 goto cleanup;
2539                         if (qgroup_to_skip) {
2540                                 ulist_del(new_roots, qgroup_to_skip, 0);
2541                                 ulist_del(record->old_roots, qgroup_to_skip,
2542                                           0);
2543                         }
2544                         ret = btrfs_qgroup_account_extent(trans, record->bytenr,
2545                                                           record->num_bytes,
2546                                                           record->old_roots,
2547                                                           new_roots);
2548                         record->old_roots = NULL;
2549                         new_roots = NULL;
2550                 }
2551 cleanup:
2552                 ulist_free(record->old_roots);
2553                 ulist_free(new_roots);
2554                 new_roots = NULL;
2555                 rb_erase(node, &delayed_refs->dirty_extent_root);
2556                 kfree(record);
2557 
2558         }
2559         trace_qgroup_num_dirty_extents(fs_info, trans->transid,
2560                                        num_dirty_extents);
2561         return ret;
2562 }
2563 
2564 /*
2565  * called from commit_transaction. Writes all changed qgroups to disk.
2566  */
2567 int btrfs_run_qgroups(struct btrfs_trans_handle *trans)
2568 {
2569         struct btrfs_fs_info *fs_info = trans->fs_info;
2570         struct btrfs_root *quota_root = fs_info->quota_root;
2571         int ret = 0;
2572 
2573         if (!quota_root)
2574                 return ret;
2575 
2576         spin_lock(&fs_info->qgroup_lock);
2577         while (!list_empty(&fs_info->dirty_qgroups)) {
2578                 struct btrfs_qgroup *qgroup;
2579                 qgroup = list_first_entry(&fs_info->dirty_qgroups,
2580                                           struct btrfs_qgroup, dirty);
2581                 list_del_init(&qgroup->dirty);
2582                 spin_unlock(&fs_info->qgroup_lock);
2583                 ret = update_qgroup_info_item(trans, qgroup);
2584                 if (ret)
2585                         fs_info->qgroup_flags |=
2586                                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2587                 ret = update_qgroup_limit_item(trans, qgroup);
2588                 if (ret)
2589                         fs_info->qgroup_flags |=
2590                                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2591                 spin_lock(&fs_info->qgroup_lock);
2592         }
2593         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2594                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_ON;
2595         else
2596                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
2597         spin_unlock(&fs_info->qgroup_lock);
2598 
2599         ret = update_qgroup_status_item(trans);
2600         if (ret)
2601                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2602 
2603         return ret;
2604 }
2605 
2606 /*
2607  * Copy the accounting information between qgroups. This is necessary
2608  * when a snapshot or a subvolume is created. Throwing an error will
2609  * cause a transaction abort so we take extra care here to only error
2610  * when a readonly fs is a reasonable outcome.
2611  */
2612 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
2613                          u64 objectid, struct btrfs_qgroup_inherit *inherit)
2614 {
2615         int ret = 0;
2616         int i;
2617         u64 *i_qgroups;
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         mutex_lock(&fs_info->qgroup_ioctl_lock);
2626         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2627                 goto out;
2628 
2629         quota_root = fs_info->quota_root;
2630         if (!quota_root) {
2631                 ret = -EINVAL;
2632                 goto out;
2633         }
2634 
2635         if (inherit) {
2636                 i_qgroups = (u64 *)(inherit + 1);
2637                 nums = inherit->num_qgroups + 2 * inherit->num_ref_copies +
2638                        2 * inherit->num_excl_copies;
2639                 for (i = 0; i < nums; ++i) {
2640                         srcgroup = find_qgroup_rb(fs_info, *i_qgroups);
2641 
2642                         /*
2643                          * Zero out invalid groups so we can ignore
2644                          * them later.
2645                          */
2646                         if (!srcgroup ||
2647                             ((srcgroup->qgroupid >> 48) <= (objectid >> 48)))
2648                                 *i_qgroups = 0ULL;
2649 
2650                         ++i_qgroups;
2651                 }
2652         }
2653 
2654         /*
2655          * create a tracking group for the subvol itself
2656          */
2657         ret = add_qgroup_item(trans, quota_root, objectid);
2658         if (ret)
2659                 goto out;
2660 
2661         /*
2662          * add qgroup to all inherited groups
2663          */
2664         if (inherit) {
2665                 i_qgroups = (u64 *)(inherit + 1);
2666                 for (i = 0; i < inherit->num_qgroups; ++i, ++i_qgroups) {
2667                         if (*i_qgroups == 0)
2668                                 continue;
2669                         ret = add_qgroup_relation_item(trans, objectid,
2670                                                        *i_qgroups);
2671                         if (ret && ret != -EEXIST)
2672                                 goto out;
2673                         ret = add_qgroup_relation_item(trans, *i_qgroups,
2674                                                        objectid);
2675                         if (ret && ret != -EEXIST)
2676                                 goto out;
2677                 }
2678                 ret = 0;
2679         }
2680 
2681 
2682         spin_lock(&fs_info->qgroup_lock);
2683 
2684         dstgroup = add_qgroup_rb(fs_info, objectid);
2685         if (IS_ERR(dstgroup)) {
2686                 ret = PTR_ERR(dstgroup);
2687                 goto unlock;
2688         }
2689 
2690         if (inherit && inherit->flags & BTRFS_QGROUP_INHERIT_SET_LIMITS) {
2691                 dstgroup->lim_flags = inherit->lim.flags;
2692                 dstgroup->max_rfer = inherit->lim.max_rfer;
2693                 dstgroup->max_excl = inherit->lim.max_excl;
2694                 dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
2695                 dstgroup->rsv_excl = inherit->lim.rsv_excl;
2696 
2697                 ret = update_qgroup_limit_item(trans, dstgroup);
2698                 if (ret) {
2699                         fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2700                         btrfs_info(fs_info,
2701                                    "unable to update quota limit for %llu",
2702                                    dstgroup->qgroupid);
2703                         goto unlock;
2704                 }
2705         }
2706 
2707         if (srcid) {
2708                 srcgroup = find_qgroup_rb(fs_info, srcid);
2709                 if (!srcgroup)
2710                         goto unlock;
2711 
2712                 /*
2713                  * We call inherit after we clone the root in order to make sure
2714                  * our counts don't go crazy, so at this point the only
2715                  * difference between the two roots should be the root node.
2716                  */
2717                 level_size = fs_info->nodesize;
2718                 dstgroup->rfer = srcgroup->rfer;
2719                 dstgroup->rfer_cmpr = srcgroup->rfer_cmpr;
2720                 dstgroup->excl = level_size;
2721                 dstgroup->excl_cmpr = level_size;
2722                 srcgroup->excl = level_size;
2723                 srcgroup->excl_cmpr = level_size;
2724 
2725                 /* inherit the limit info */
2726                 dstgroup->lim_flags = srcgroup->lim_flags;
2727                 dstgroup->max_rfer = srcgroup->max_rfer;
2728                 dstgroup->max_excl = srcgroup->max_excl;
2729                 dstgroup->rsv_rfer = srcgroup->rsv_rfer;
2730                 dstgroup->rsv_excl = srcgroup->rsv_excl;
2731 
2732                 qgroup_dirty(fs_info, dstgroup);
2733                 qgroup_dirty(fs_info, srcgroup);
2734         }
2735 
2736         if (!inherit)
2737                 goto unlock;
2738 
2739         i_qgroups = (u64 *)(inherit + 1);
2740         for (i = 0; i < inherit->num_qgroups; ++i) {
2741                 if (*i_qgroups) {
2742                         ret = add_relation_rb(fs_info, objectid, *i_qgroups);
2743                         if (ret)
2744                                 goto unlock;
2745                 }
2746                 ++i_qgroups;
2747         }
2748 
2749         for (i = 0; i <  inherit->num_ref_copies; ++i, i_qgroups += 2) {
2750                 struct btrfs_qgroup *src;
2751                 struct btrfs_qgroup *dst;
2752 
2753                 if (!i_qgroups[0] || !i_qgroups[1])
2754                         continue;
2755 
2756                 src = find_qgroup_rb(fs_info, i_qgroups[0]);
2757                 dst = find_qgroup_rb(fs_info, i_qgroups[1]);
2758 
2759                 if (!src || !dst) {
2760                         ret = -EINVAL;
2761                         goto unlock;
2762                 }
2763 
2764                 dst->rfer = src->rfer - level_size;
2765                 dst->rfer_cmpr = src->rfer_cmpr - level_size;
2766         }
2767         for (i = 0; i <  inherit->num_excl_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->excl = src->excl + level_size;
2783                 dst->excl_cmpr = src->excl_cmpr + level_size;
2784         }
2785 
2786 unlock:
2787         spin_unlock(&fs_info->qgroup_lock);
2788 out:
2789         mutex_unlock(&fs_info->qgroup_ioctl_lock);
2790         return ret;
2791 }
2792 
2793 /*
2794  * Two limits to commit transaction in advance.
2795  *
2796  * For RATIO, it will be 1/RATIO of the remaining limit as threshold.
2797  * For SIZE, it will be in byte unit as threshold.
2798  */
2799 #define QGROUP_FREE_RATIO               32
2800 #define QGROUP_FREE_SIZE                SZ_32M
2801 static bool qgroup_check_limits(struct btrfs_fs_info *fs_info,
2802                                 const struct btrfs_qgroup *qg, u64 num_bytes)
2803 {
2804         u64 free;
2805         u64 threshold;
2806 
2807         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
2808             qgroup_rsv_total(qg) + (s64)qg->rfer + num_bytes > qg->max_rfer)
2809                 return false;
2810 
2811         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
2812             qgroup_rsv_total(qg) + (s64)qg->excl + num_bytes > qg->max_excl)
2813                 return false;
2814 
2815         /*
2816          * Even if we passed the check, it's better to check if reservation
2817          * for meta_pertrans is pushing us near limit.
2818          * If there is too much pertrans reservation or it's near the limit,
2819          * let's try commit transaction to free some, using transaction_kthread
2820          */
2821         if ((qg->lim_flags & (BTRFS_QGROUP_LIMIT_MAX_RFER |
2822                               BTRFS_QGROUP_LIMIT_MAX_EXCL))) {
2823                 if (qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
2824                         free = qg->max_excl - qgroup_rsv_total(qg) - qg->excl;
2825                         threshold = min_t(u64, qg->max_excl / QGROUP_FREE_RATIO,
2826                                           QGROUP_FREE_SIZE);
2827                 } else {
2828                         free = qg->max_rfer - qgroup_rsv_total(qg) - qg->rfer;
2829                         threshold = min_t(u64, qg->max_rfer / QGROUP_FREE_RATIO,
2830                                           QGROUP_FREE_SIZE);
2831                 }
2832 
2833                 /*
2834                  * Use transaction_kthread to commit transaction, so we no
2835                  * longer need to bother nested transaction nor lock context.
2836                  */
2837                 if (free < threshold)
2838                         btrfs_commit_transaction_locksafe(fs_info);
2839         }
2840 
2841         return true;
2842 }
2843 
2844 static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce,
2845                           enum btrfs_qgroup_rsv_type type)
2846 {
2847         struct btrfs_root *quota_root;
2848         struct btrfs_qgroup *qgroup;
2849         struct btrfs_fs_info *fs_info = root->fs_info;
2850         u64 ref_root = root->root_key.objectid;
2851         int ret = 0;
2852         struct ulist_node *unode;
2853         struct ulist_iterator uiter;
2854 
2855         if (!is_fstree(ref_root))
2856                 return 0;
2857 
2858         if (num_bytes == 0)
2859                 return 0;
2860 
2861         if (test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags) &&
2862             capable(CAP_SYS_RESOURCE))
2863                 enforce = false;
2864 
2865         spin_lock(&fs_info->qgroup_lock);
2866         quota_root = fs_info->quota_root;
2867         if (!quota_root)
2868                 goto out;
2869 
2870         qgroup = find_qgroup_rb(fs_info, ref_root);
2871         if (!qgroup)
2872                 goto out;
2873 
2874         /*
2875          * in a first step, we check all affected qgroups if any limits would
2876          * be exceeded
2877          */
2878         ulist_reinit(fs_info->qgroup_ulist);
2879         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2880                         qgroup_to_aux(qgroup), GFP_ATOMIC);
2881         if (ret < 0)
2882                 goto out;
2883         ULIST_ITER_INIT(&uiter);
2884         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2885                 struct btrfs_qgroup *qg;
2886                 struct btrfs_qgroup_list *glist;
2887 
2888                 qg = unode_aux_to_qgroup(unode);
2889 
2890                 if (enforce && !qgroup_check_limits(fs_info, qg, num_bytes)) {
2891                         ret = -EDQUOT;
2892                         goto out;
2893                 }
2894 
2895                 list_for_each_entry(glist, &qg->groups, next_group) {
2896                         ret = ulist_add(fs_info->qgroup_ulist,
2897                                         glist->group->qgroupid,
2898                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
2899                         if (ret < 0)
2900                                 goto out;
2901                 }
2902         }
2903         ret = 0;
2904         /*
2905          * no limits exceeded, now record the reservation into all qgroups
2906          */
2907         ULIST_ITER_INIT(&uiter);
2908         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2909                 struct btrfs_qgroup *qg;
2910 
2911                 qg = unode_aux_to_qgroup(unode);
2912 
2913                 qgroup_rsv_add(fs_info, qg, num_bytes, type);
2914         }
2915 
2916 out:
2917         spin_unlock(&fs_info->qgroup_lock);
2918         return ret;
2919 }
2920 
2921 /*
2922  * Free @num_bytes of reserved space with @type for qgroup.  (Normally level 0
2923  * qgroup).
2924  *
2925  * Will handle all higher level qgroup too.
2926  *
2927  * NOTE: If @num_bytes is (u64)-1, this means to free all bytes of this qgroup.
2928  * This special case is only used for META_PERTRANS type.
2929  */
2930 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
2931                                u64 ref_root, u64 num_bytes,
2932                                enum btrfs_qgroup_rsv_type type)
2933 {
2934         struct btrfs_root *quota_root;
2935         struct btrfs_qgroup *qgroup;
2936         struct ulist_node *unode;
2937         struct ulist_iterator uiter;
2938         int ret = 0;
2939 
2940         if (!is_fstree(ref_root))
2941                 return;
2942 
2943         if (num_bytes == 0)
2944                 return;
2945 
2946         if (num_bytes == (u64)-1 && type != BTRFS_QGROUP_RSV_META_PERTRANS) {
2947                 WARN(1, "%s: Invalid type to free", __func__);
2948                 return;
2949         }
2950         spin_lock(&fs_info->qgroup_lock);
2951 
2952         quota_root = fs_info->quota_root;
2953         if (!quota_root)
2954                 goto out;
2955 
2956         qgroup = find_qgroup_rb(fs_info, ref_root);
2957         if (!qgroup)
2958                 goto out;
2959 
2960         if (num_bytes == (u64)-1)
2961                 /*
2962                  * We're freeing all pertrans rsv, get reserved value from
2963                  * level 0 qgroup as real num_bytes to free.
2964                  */
2965                 num_bytes = qgroup->rsv.values[type];
2966 
2967         ulist_reinit(fs_info->qgroup_ulist);
2968         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
2969                         qgroup_to_aux(qgroup), GFP_ATOMIC);
2970         if (ret < 0)
2971                 goto out;
2972         ULIST_ITER_INIT(&uiter);
2973         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
2974                 struct btrfs_qgroup *qg;
2975                 struct btrfs_qgroup_list *glist;
2976 
2977                 qg = unode_aux_to_qgroup(unode);
2978 
2979                 qgroup_rsv_release(fs_info, qg, num_bytes, type);
2980 
2981                 list_for_each_entry(glist, &qg->groups, next_group) {
2982                         ret = ulist_add(fs_info->qgroup_ulist,
2983                                         glist->group->qgroupid,
2984                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
2985                         if (ret < 0)
2986                                 goto out;
2987                 }
2988         }
2989 
2990 out:
2991         spin_unlock(&fs_info->qgroup_lock);
2992 }
2993 
2994 /*
2995  * Check if the leaf is the last leaf. Which means all node pointers
2996  * are at their last position.
2997  */
2998 static bool is_last_leaf(struct btrfs_path *path)
2999 {
3000         int i;
3001 
3002         for (i = 1; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
3003                 if (path->slots[i] != btrfs_header_nritems(path->nodes[i]) - 1)
3004                         return false;
3005         }
3006         return true;
3007 }
3008 
3009 /*
3010  * returns < 0 on error, 0 when more leafs are to be scanned.
3011  * returns 1 when done.
3012  */
3013 static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
3014                               struct btrfs_path *path)
3015 {
3016         struct btrfs_fs_info *fs_info = trans->fs_info;
3017         struct btrfs_key found;
3018         struct extent_buffer *scratch_leaf = NULL;
3019         struct ulist *roots = NULL;
3020         u64 num_bytes;
3021         bool done;
3022         int slot;
3023         int ret;
3024 
3025         mutex_lock(&fs_info->qgroup_rescan_lock);
3026         ret = btrfs_search_slot_for_read(fs_info->extent_root,
3027                                          &fs_info->qgroup_rescan_progress,
3028                                          path, 1, 0);
3029 
3030         btrfs_debug(fs_info,
3031                 "current progress key (%llu %u %llu), search_slot ret %d",
3032                 fs_info->qgroup_rescan_progress.objectid,
3033                 fs_info->qgroup_rescan_progress.type,
3034                 fs_info->qgroup_rescan_progress.offset, ret);
3035 
3036         if (ret) {
3037                 /*
3038                  * The rescan is about to end, we will not be scanning any
3039                  * further blocks. We cannot unset the RESCAN flag here, because
3040                  * we want to commit the transaction if everything went well.
3041                  * To make the live accounting work in this phase, we set our
3042                  * scan progress pointer such that every real extent objectid
3043                  * will be smaller.
3044                  */
3045                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3046                 btrfs_release_path(path);
3047                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3048                 return ret;
3049         }
3050         done = is_last_leaf(path);
3051 
3052         btrfs_item_key_to_cpu(path->nodes[0], &found,
3053                               btrfs_header_nritems(path->nodes[0]) - 1);
3054         fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
3055 
3056         scratch_leaf = btrfs_clone_extent_buffer(path->nodes[0]);
3057         if (!scratch_leaf) {
3058                 ret = -ENOMEM;
3059                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3060                 goto out;
3061         }
3062         slot = path->slots[0];
3063         btrfs_release_path(path);
3064         mutex_unlock(&fs_info->qgroup_rescan_lock);
3065 
3066         for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
3067                 btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
3068                 if (found.type != BTRFS_EXTENT_ITEM_KEY &&
3069                     found.type != BTRFS_METADATA_ITEM_KEY)
3070                         continue;
3071                 if (found.type == BTRFS_METADATA_ITEM_KEY)
3072                         num_bytes = fs_info->nodesize;
3073                 else
3074                         num_bytes = found.offset;
3075 
3076                 ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0,
3077                                            &roots, false);
3078                 if (ret < 0)
3079                         goto out;
3080                 /* For rescan, just pass old_roots as NULL */
3081                 ret = btrfs_qgroup_account_extent(trans, found.objectid,
3082                                                   num_bytes, NULL, roots);
3083                 if (ret < 0)
3084                         goto out;
3085         }
3086 out:
3087         if (scratch_leaf)
3088                 free_extent_buffer(scratch_leaf);
3089 
3090         if (done && !ret) {
3091                 ret = 1;
3092                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3093         }
3094         return ret;
3095 }
3096 
3097 static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
3098 {
3099         struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
3100                                                      qgroup_rescan_work);
3101         struct btrfs_path *path;
3102         struct btrfs_trans_handle *trans = NULL;
3103         int err = -ENOMEM;
3104         int ret = 0;
3105 
3106         path = btrfs_alloc_path();
3107         if (!path)
3108                 goto out;
3109         /*
3110          * Rescan should only search for commit root, and any later difference
3111          * should be recorded by qgroup
3112          */
3113         path->search_commit_root = 1;
3114         path->skip_locking = 1;
3115 
3116         err = 0;
3117         while (!err && !btrfs_fs_closing(fs_info)) {
3118                 trans = btrfs_start_transaction(fs_info->fs_root, 0);
3119                 if (IS_ERR(trans)) {
3120                         err = PTR_ERR(trans);
3121                         break;
3122                 }
3123                 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
3124                         err = -EINTR;
3125                 } else {
3126                         err = qgroup_rescan_leaf(trans, path);
3127                 }
3128                 if (err > 0)
3129                         btrfs_commit_transaction(trans);
3130                 else
3131                         btrfs_end_transaction(trans);
3132         }
3133 
3134 out:
3135         btrfs_free_path(path);
3136 
3137         mutex_lock(&fs_info->qgroup_rescan_lock);
3138         if (!btrfs_fs_closing(fs_info))
3139                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3140 
3141         if (err > 0 &&
3142             fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
3143                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3144         } else if (err < 0) {
3145                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3146         }
3147         mutex_unlock(&fs_info->qgroup_rescan_lock);
3148 
3149         /*
3150          * only update status, since the previous part has already updated the
3151          * qgroup info.
3152          */
3153         trans = btrfs_start_transaction(fs_info->quota_root, 1);
3154         if (IS_ERR(trans)) {
3155                 err = PTR_ERR(trans);
3156                 btrfs_err(fs_info,
3157                           "fail to start transaction for status update: %d",
3158                           err);
3159                 goto done;
3160         }
3161         ret = update_qgroup_status_item(trans);
3162         if (ret < 0) {
3163                 err = ret;
3164                 btrfs_err(fs_info, "fail to update qgroup status: %d", err);
3165         }
3166         btrfs_end_transaction(trans);
3167 
3168         if (btrfs_fs_closing(fs_info)) {
3169                 btrfs_info(fs_info, "qgroup scan paused");
3170         } else if (err >= 0) {
3171                 btrfs_info(fs_info, "qgroup scan completed%s",
3172                         err > 0 ? " (inconsistency flag cleared)" : "");
3173         } else {
3174                 btrfs_err(fs_info, "qgroup scan failed with %d", err);
3175         }
3176 
3177 done:
3178         mutex_lock(&fs_info->qgroup_rescan_lock);
3179         fs_info->qgroup_rescan_running = false;
3180         mutex_unlock(&fs_info->qgroup_rescan_lock);
3181         complete_all(&fs_info->qgroup_rescan_completion);
3182 }
3183 
3184 /*
3185  * Checks that (a) no rescan is running and (b) quota is enabled. Allocates all
3186  * memory required for the rescan context.
3187  */
3188 static int
3189 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
3190                    int init_flags)
3191 {
3192         int ret = 0;
3193 
3194         if (!init_flags) {
3195                 /* we're resuming qgroup rescan at mount time */
3196                 if (!(fs_info->qgroup_flags &
3197                       BTRFS_QGROUP_STATUS_FLAG_RESCAN)) {
3198                         btrfs_warn(fs_info,
3199                         "qgroup rescan init failed, qgroup is not enabled");
3200                         ret = -EINVAL;
3201                 } else if (!(fs_info->qgroup_flags &
3202                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3203                         btrfs_warn(fs_info,
3204                         "qgroup rescan init failed, qgroup rescan is not queued");
3205                         ret = -EINVAL;
3206                 }
3207 
3208                 if (ret)
3209                         return ret;
3210         }
3211 
3212         mutex_lock(&fs_info->qgroup_rescan_lock);
3213         spin_lock(&fs_info->qgroup_lock);
3214 
3215         if (init_flags) {
3216                 if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
3217                         btrfs_warn(fs_info,
3218                                    "qgroup rescan is already in progress");
3219                         ret = -EINPROGRESS;
3220                 } else if (!(fs_info->qgroup_flags &
3221                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3222                         btrfs_warn(fs_info,
3223                         "qgroup rescan init failed, qgroup is not enabled");
3224                         ret = -EINVAL;
3225                 }
3226 
3227                 if (ret) {
3228                         spin_unlock(&fs_info->qgroup_lock);
3229                         mutex_unlock(&fs_info->qgroup_rescan_lock);
3230                         return ret;
3231                 }
3232                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3233         }
3234 
3235         memset(&fs_info->qgroup_rescan_progress, 0,
3236                 sizeof(fs_info->qgroup_rescan_progress));
3237         fs_info->qgroup_rescan_progress.objectid = progress_objectid;
3238         init_completion(&fs_info->qgroup_rescan_completion);
3239         fs_info->qgroup_rescan_running = true;
3240 
3241         spin_unlock(&fs_info->qgroup_lock);
3242         mutex_unlock(&fs_info->qgroup_rescan_lock);
3243 
3244         memset(&fs_info->qgroup_rescan_work, 0,
3245                sizeof(fs_info->qgroup_rescan_work));
3246         btrfs_init_work(&fs_info->qgroup_rescan_work,
3247                         btrfs_qgroup_rescan_helper,
3248                         btrfs_qgroup_rescan_worker, NULL, NULL);
3249         return 0;
3250 }
3251 
3252 static void
3253 qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info)
3254 {
3255         struct rb_node *n;
3256         struct btrfs_qgroup *qgroup;
3257 
3258         spin_lock(&fs_info->qgroup_lock);
3259         /* clear all current qgroup tracking information */
3260         for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
3261                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
3262                 qgroup->rfer = 0;
3263                 qgroup->rfer_cmpr = 0;
3264                 qgroup->excl = 0;
3265                 qgroup->excl_cmpr = 0;
3266                 qgroup_dirty(fs_info, qgroup);
3267         }
3268         spin_unlock(&fs_info->qgroup_lock);
3269 }
3270 
3271 int
3272 btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
3273 {
3274         int ret = 0;
3275         struct btrfs_trans_handle *trans;
3276 
3277         ret = qgroup_rescan_init(fs_info, 0, 1);
3278         if (ret)
3279                 return ret;
3280 
3281         /*
3282          * We have set the rescan_progress to 0, which means no more
3283          * delayed refs will be accounted by btrfs_qgroup_account_ref.
3284          * However, btrfs_qgroup_account_ref may be right after its call
3285          * to btrfs_find_all_roots, in which case it would still do the
3286          * accounting.
3287          * To solve this, we're committing the transaction, which will
3288          * ensure we run all delayed refs and only after that, we are
3289          * going to clear all tracking information for a clean start.
3290          */
3291 
3292         trans = btrfs_join_transaction(fs_info->fs_root);
3293         if (IS_ERR(trans)) {
3294                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3295                 return PTR_ERR(trans);
3296         }
3297         ret = btrfs_commit_transaction(trans);
3298         if (ret) {
3299                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3300                 return ret;
3301         }
3302 
3303         qgroup_rescan_zero_tracking(fs_info);
3304 
3305         btrfs_queue_work(fs_info->qgroup_rescan_workers,
3306                          &fs_info->qgroup_rescan_work);
3307 
3308         return 0;
3309 }
3310 
3311 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
3312                                      bool interruptible)
3313 {
3314         int running;
3315         int ret = 0;
3316 
3317         mutex_lock(&fs_info->qgroup_rescan_lock);
3318         spin_lock(&fs_info->qgroup_lock);
3319         running = fs_info->qgroup_rescan_running;
3320         spin_unlock(&fs_info->qgroup_lock);
3321         mutex_unlock(&fs_info->qgroup_rescan_lock);
3322 
3323         if (!running)
3324                 return 0;
3325 
3326         if (interruptible)
3327                 ret = wait_for_completion_interruptible(
3328                                         &fs_info->qgroup_rescan_completion);
3329         else
3330                 wait_for_completion(&fs_info->qgroup_rescan_completion);
3331 
3332         return ret;
3333 }
3334 
3335 /*
3336  * this is only called from open_ctree where we're still single threaded, thus
3337  * locking is omitted here.
3338  */
3339 void
3340 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
3341 {
3342         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
3343                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
3344                                  &fs_info->qgroup_rescan_work);
3345 }
3346 
3347 /*
3348  * Reserve qgroup space for range [start, start + len).
3349  *
3350  * This function will either reserve space from related qgroups or doing
3351  * nothing if the range is already reserved.
3352  *
3353  * Return 0 for successful reserve
3354  * Return <0 for error (including -EQUOT)
3355  *
3356  * NOTE: this function may sleep for memory allocation.
3357  *       if btrfs_qgroup_reserve_data() is called multiple times with
3358  *       same @reserved, caller must ensure when error happens it's OK
3359  *       to free *ALL* reserved space.
3360  */
3361 int btrfs_qgroup_reserve_data(struct inode *inode,
3362                         struct extent_changeset **reserved_ret, u64 start,
3363                         u64 len)
3364 {
3365         struct btrfs_root *root = BTRFS_I(inode)->root;
3366         struct ulist_node *unode;
3367         struct ulist_iterator uiter;
3368         struct extent_changeset *reserved;
3369         u64 orig_reserved;
3370         u64 to_reserve;
3371         int ret;
3372 
3373         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags) ||
3374             !is_fstree(root->root_key.objectid) || len == 0)
3375                 return 0;
3376 
3377         /* @reserved parameter is mandatory for qgroup */
3378         if (WARN_ON(!reserved_ret))
3379                 return -EINVAL;
3380         if (!*reserved_ret) {
3381                 *reserved_ret = extent_changeset_alloc();
3382                 if (!*reserved_ret)
3383                         return -ENOMEM;
3384         }
3385         reserved = *reserved_ret;
3386         /* Record already reserved space */
3387         orig_reserved = reserved->bytes_changed;
3388         ret = set_record_extent_bits(&BTRFS_I(inode)->io_tree, start,
3389                         start + len -1, EXTENT_QGROUP_RESERVED, reserved);
3390 
3391         /* Newly reserved space */
3392         to_reserve = reserved->bytes_changed - orig_reserved;
3393         trace_btrfs_qgroup_reserve_data(inode, start, len,
3394                                         to_reserve, QGROUP_RESERVE);
3395         if (ret < 0)
3396                 goto cleanup;
3397         ret = qgroup_reserve(root, to_reserve, true, BTRFS_QGROUP_RSV_DATA);
3398         if (ret < 0)
3399                 goto cleanup;
3400 
3401         return ret;
3402 
3403 cleanup:
3404         /* cleanup *ALL* already reserved ranges */
3405         ULIST_ITER_INIT(&uiter);
3406         while ((unode = ulist_next(&reserved->range_changed, &uiter)))
3407                 clear_extent_bit(&BTRFS_I(inode)->io_tree, unode->val,
3408                                  unode->aux, EXTENT_QGROUP_RESERVED, 0, 0, NULL);
3409         extent_changeset_release(reserved);
3410         return ret;
3411 }
3412 
3413 /* Free ranges specified by @reserved, normally in error path */
3414 static int qgroup_free_reserved_data(struct inode *inode,
3415                         struct extent_changeset *reserved, u64 start, u64 len)
3416 {
3417         struct btrfs_root *root = BTRFS_I(inode)->root;
3418         struct ulist_node *unode;
3419         struct ulist_iterator uiter;
3420         struct extent_changeset changeset;
3421         int freed = 0;
3422         int ret;
3423 
3424         extent_changeset_init(&changeset);
3425         len = round_up(start + len, root->fs_info->sectorsize);
3426         start = round_down(start, root->fs_info->sectorsize);
3427 
3428         ULIST_ITER_INIT(&uiter);
3429         while ((unode = ulist_next(&reserved->range_changed, &uiter))) {
3430                 u64 range_start = unode->val;
3431                 /* unode->aux is the inclusive end */
3432                 u64 range_len = unode->aux - range_start + 1;
3433                 u64 free_start;
3434                 u64 free_len;
3435 
3436                 extent_changeset_release(&changeset);
3437 
3438                 /* Only free range in range [start, start + len) */
3439                 if (range_start >= start + len ||
3440                     range_start + range_len <= start)
3441                         continue;
3442                 free_start = max(range_start, start);
3443                 free_len = min(start + len, range_start + range_len) -
3444                            free_start;
3445                 /*
3446                  * TODO: To also modify reserved->ranges_reserved to reflect
3447                  * the modification.
3448                  *
3449                  * However as long as we free qgroup reserved according to
3450                  * EXTENT_QGROUP_RESERVED, we won't double free.
3451                  * So not need to rush.
3452                  */
3453                 ret = clear_record_extent_bits(&BTRFS_I(inode)->io_failure_tree,
3454                                 free_start, free_start + free_len - 1,
3455                                 EXTENT_QGROUP_RESERVED, &changeset);
3456                 if (ret < 0)
3457                         goto out;
3458                 freed += changeset.bytes_changed;
3459         }
3460         btrfs_qgroup_free_refroot(root->fs_info, root->root_key.objectid, freed,
3461                                   BTRFS_QGROUP_RSV_DATA);
3462         ret = freed;
3463 out:
3464         extent_changeset_release(&changeset);
3465         return ret;
3466 }
3467 
3468 static int __btrfs_qgroup_release_data(struct inode *inode,
3469                         struct extent_changeset *reserved, u64 start, u64 len,
3470                         int free)
3471 {
3472         struct extent_changeset changeset;
3473         int trace_op = QGROUP_RELEASE;
3474         int ret;
3475 
3476         if (!test_bit(BTRFS_FS_QUOTA_ENABLED,
3477                       &BTRFS_I(inode)->root->fs_info->flags))
3478                 return 0;
3479 
3480         /* In release case, we shouldn't have @reserved */
3481         WARN_ON(!free && reserved);
3482         if (free && reserved)
3483                 return qgroup_free_reserved_data(inode, reserved, start, len);
3484         extent_changeset_init(&changeset);
3485         ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, start, 
3486                         start + len -1, EXTENT_QGROUP_RESERVED, &changeset);
3487         if (ret < 0)
3488                 goto out;
3489 
3490         if (free)
3491                 trace_op = QGROUP_FREE;
3492         trace_btrfs_qgroup_release_data(inode, start, len,
3493                                         changeset.bytes_changed, trace_op);
3494         if (free)
3495                 btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3496                                 BTRFS_I(inode)->root->root_key.objectid,
3497                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3498         ret = changeset.bytes_changed;
3499 out:
3500         extent_changeset_release(&changeset);
3501         return ret;
3502 }
3503 
3504 /*
3505  * Free a reserved space range from io_tree and related qgroups
3506  *
3507  * Should be called when a range of pages get invalidated before reaching disk.
3508  * Or for error cleanup case.
3509  * if @reserved is given, only reserved range in [@start, @start + @len) will
3510  * be freed.
3511  *
3512  * For data written to disk, use btrfs_qgroup_release_data().
3513  *
3514  * NOTE: This function may sleep for memory allocation.
3515  */
3516 int btrfs_qgroup_free_data(struct inode *inode,
3517                         struct extent_changeset *reserved, u64 start, u64 len)
3518 {
3519         return __btrfs_qgroup_release_data(inode, reserved, start, len, 1);
3520 }
3521 
3522 /*
3523  * Release a reserved space range from io_tree only.
3524  *
3525  * Should be called when a range of pages get written to disk and corresponding
3526  * FILE_EXTENT is inserted into corresponding root.
3527  *
3528  * Since new qgroup accounting framework will only update qgroup numbers at
3529  * commit_transaction() time, its reserved space shouldn't be freed from
3530  * related qgroups.
3531  *
3532  * But we should release the range from io_tree, to allow further write to be
3533  * COWed.
3534  *
3535  * NOTE: This function may sleep for memory allocation.
3536  */
3537 int btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len)
3538 {
3539         return __btrfs_qgroup_release_data(inode, NULL, start, len, 0);
3540 }
3541 
3542 static void add_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3543                               enum btrfs_qgroup_rsv_type type)
3544 {
3545         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3546             type != BTRFS_QGROUP_RSV_META_PERTRANS)
3547                 return;
3548         if (num_bytes == 0)
3549                 return;
3550 
3551         spin_lock(&root->qgroup_meta_rsv_lock);
3552         if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
3553                 root->qgroup_meta_rsv_prealloc += num_bytes;
3554         else
3555                 root->qgroup_meta_rsv_pertrans += num_bytes;
3556         spin_unlock(&root->qgroup_meta_rsv_lock);
3557 }
3558 
3559 static int sub_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3560                              enum btrfs_qgroup_rsv_type type)
3561 {
3562         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3563             type != BTRFS_QGROUP_RSV_META_PERTRANS)
3564                 return 0;
3565         if (num_bytes == 0)
3566                 return 0;
3567 
3568         spin_lock(&root->qgroup_meta_rsv_lock);
3569         if (type == BTRFS_QGROUP_RSV_META_PREALLOC) {
3570                 num_bytes = min_t(u64, root->qgroup_meta_rsv_prealloc,
3571                                   num_bytes);
3572                 root->qgroup_meta_rsv_prealloc -= num_bytes;
3573         } else {
3574                 num_bytes = min_t(u64, root->qgroup_meta_rsv_pertrans,
3575                                   num_bytes);
3576                 root->qgroup_meta_rsv_pertrans -= num_bytes;
3577         }
3578         spin_unlock(&root->qgroup_meta_rsv_lock);
3579         return num_bytes;
3580 }
3581 
3582 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
3583                                 enum btrfs_qgroup_rsv_type type, bool enforce)
3584 {
3585         struct btrfs_fs_info *fs_info = root->fs_info;
3586         int ret;
3587 
3588         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3589             !is_fstree(root->root_key.objectid) || num_bytes == 0)
3590                 return 0;
3591 
3592         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3593         trace_qgroup_meta_reserve(root, type, (s64)num_bytes);
3594         ret = qgroup_reserve(root, num_bytes, enforce, type);
3595         if (ret < 0)
3596                 return ret;
3597         /*
3598          * Record what we have reserved into root.
3599          *
3600          * To avoid quota disabled->enabled underflow.
3601          * In that case, we may try to free space we haven't reserved
3602          * (since quota was disabled), so record what we reserved into root.
3603          * And ensure later release won't underflow this number.
3604          */
3605         add_root_meta_rsv(root, num_bytes, type);
3606         return ret;
3607 }
3608 
3609 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root)
3610 {
3611         struct btrfs_fs_info *fs_info = root->fs_info;
3612 
3613         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3614             !is_fstree(root->root_key.objectid))
3615                 return;
3616 
3617         /* TODO: Update trace point to handle such free */
3618         trace_qgroup_meta_free_all_pertrans(root);
3619         /* Special value -1 means to free all reserved space */
3620         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid, (u64)-1,
3621                                   BTRFS_QGROUP_RSV_META_PERTRANS);
3622 }
3623 
3624 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
3625                               enum btrfs_qgroup_rsv_type type)
3626 {
3627         struct btrfs_fs_info *fs_info = root->fs_info;
3628 
3629         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3630             !is_fstree(root->root_key.objectid))
3631                 return;
3632 
3633         /*
3634          * reservation for META_PREALLOC can happen before quota is enabled,
3635          * which can lead to underflow.
3636          * Here ensure we will only free what we really have reserved.
3637          */
3638         num_bytes = sub_root_meta_rsv(root, num_bytes, type);
3639         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3640         trace_qgroup_meta_reserve(root, type, -(s64)num_bytes);
3641         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
3642                                   num_bytes, type);
3643 }
3644 
3645 static void qgroup_convert_meta(struct btrfs_fs_info *fs_info, u64 ref_root,
3646                                 int num_bytes)
3647 {
3648         struct btrfs_root *quota_root = fs_info->quota_root;
3649         struct btrfs_qgroup *qgroup;
3650         struct ulist_node *unode;
3651         struct ulist_iterator uiter;
3652         int ret = 0;
3653 
3654         if (num_bytes == 0)
3655                 return;
3656         if (!quota_root)
3657                 return;
3658 
3659         spin_lock(&fs_info->qgroup_lock);
3660         qgroup = find_qgroup_rb(fs_info, ref_root);
3661         if (!qgroup)
3662                 goto out;
3663         ulist_reinit(fs_info->qgroup_ulist);
3664         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
3665                        qgroup_to_aux(qgroup), GFP_ATOMIC);
3666         if (ret < 0)
3667                 goto out;
3668         ULIST_ITER_INIT(&uiter);
3669         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
3670                 struct btrfs_qgroup *qg;
3671                 struct btrfs_qgroup_list *glist;
3672 
3673                 qg = unode_aux_to_qgroup(unode);
3674 
3675                 qgroup_rsv_release(fs_info, qg, num_bytes,
3676                                 BTRFS_QGROUP_RSV_META_PREALLOC);
3677                 qgroup_rsv_add(fs_info, qg, num_bytes,
3678                                 BTRFS_QGROUP_RSV_META_PERTRANS);
3679                 list_for_each_entry(glist, &qg->groups, next_group) {
3680                         ret = ulist_add(fs_info->qgroup_ulist,
3681                                         glist->group->qgroupid,
3682                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
3683                         if (ret < 0)
3684                                 goto out;
3685                 }
3686         }
3687 out:
3688         spin_unlock(&fs_info->qgroup_lock);
3689 }
3690 
3691 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes)
3692 {
3693         struct btrfs_fs_info *fs_info = root->fs_info;
3694 
3695         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3696             !is_fstree(root->root_key.objectid))
3697                 return;
3698         /* Same as btrfs_qgroup_free_meta_prealloc() */
3699         num_bytes = sub_root_meta_rsv(root, num_bytes,
3700                                       BTRFS_QGROUP_RSV_META_PREALLOC);
3701         trace_qgroup_meta_convert(root, num_bytes);
3702         qgroup_convert_meta(fs_info, root->root_key.objectid, num_bytes);
3703 }
3704 
3705 /*
3706  * Check qgroup reserved space leaking, normally at destroy inode
3707  * time
3708  */
3709 void btrfs_qgroup_check_reserved_leak(struct inode *inode)
3710 {
3711         struct extent_changeset changeset;
3712         struct ulist_node *unode;
3713         struct ulist_iterator iter;
3714         int ret;
3715 
3716         extent_changeset_init(&changeset);
3717         ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree, 0, (u64)-1,
3718                         EXTENT_QGROUP_RESERVED, &changeset);
3719 
3720         WARN_ON(ret < 0);
3721         if (WARN_ON(changeset.bytes_changed)) {
3722                 ULIST_ITER_INIT(&iter);
3723                 while ((unode = ulist_next(&changeset.range_changed, &iter))) {
3724                         btrfs_warn(BTRFS_I(inode)->root->fs_info,
3725                                 "leaking qgroup reserved space, ino: %lu, start: %llu, end: %llu",
3726                                 inode->i_ino, unode->val, unode->aux);
3727                 }
3728                 btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
3729                                 BTRFS_I(inode)->root->root_key.objectid,
3730                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3731 
3732         }
3733         extent_changeset_release(&changeset);
3734 }
3735 
3736 void btrfs_qgroup_init_swapped_blocks(
3737         struct btrfs_qgroup_swapped_blocks *swapped_blocks)
3738 {
3739         int i;
3740 
3741         spin_lock_init(&swapped_blocks->lock);
3742         for (i = 0; i < BTRFS_MAX_LEVEL; i++)
3743                 swapped_blocks->blocks[i] = RB_ROOT;
3744         swapped_blocks->swapped = false;
3745 }
3746 
3747 /*
3748  * Delete all swapped blocks record of @root.
3749  * Every record here means we skipped a full subtree scan for qgroup.
3750  *
3751  * Gets called when committing one transaction.
3752  */
3753 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root)
3754 {
3755         struct btrfs_qgroup_swapped_blocks *swapped_blocks;
3756         int i;
3757 
3758         swapped_blocks = &root->swapped_blocks;
3759 
3760         spin_lock(&swapped_blocks->lock);
3761         if (!swapped_blocks->swapped)
3762                 goto out;
3763         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3764                 struct rb_root *cur_root = &swapped_blocks->blocks[i];
3765                 struct btrfs_qgroup_swapped_block *entry;
3766                 struct btrfs_qgroup_swapped_block *next;
3767 
3768                 rbtree_postorder_for_each_entry_safe(entry, next, cur_root,
3769                                                      node)
3770                         kfree(entry);
3771                 swapped_blocks->blocks[i] = RB_ROOT;
3772         }
3773         swapped_blocks->swapped = false;
3774 out:
3775         spin_unlock(&swapped_blocks->lock);
3776 }
3777 
3778 /*
3779  * Add subtree roots record into @subvol_root.
3780  *
3781  * @subvol_root:        tree root of the subvolume tree get swapped
3782  * @bg:                 block group under balance
3783  * @subvol_parent/slot: pointer to the subtree root in subvolume tree
3784  * @reloc_parent/slot:  pointer to the subtree root in reloc tree
3785  *                      BOTH POINTERS ARE BEFORE TREE SWAP
3786  * @last_snapshot:      last snapshot generation of the subvolume tree
3787  */
3788 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
3789                 struct btrfs_root *subvol_root,
3790                 struct btrfs_block_group_cache *bg,
3791                 struct extent_buffer *subvol_parent, int subvol_slot,
3792                 struct extent_buffer *reloc_parent, int reloc_slot,
3793                 u64 last_snapshot)
3794 {
3795         struct btrfs_fs_info *fs_info = subvol_root->fs_info;
3796         struct btrfs_qgroup_swapped_blocks *blocks = &subvol_root->swapped_blocks;
3797         struct btrfs_qgroup_swapped_block *block;
3798         struct rb_node **cur;
3799         struct rb_node *parent = NULL;
3800         int level = btrfs_header_level(subvol_parent) - 1;
3801         int ret = 0;
3802 
3803         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
3804                 return 0;
3805 
3806         if (btrfs_node_ptr_generation(subvol_parent, subvol_slot) >
3807             btrfs_node_ptr_generation(reloc_parent, reloc_slot)) {
3808                 btrfs_err_rl(fs_info,
3809                 "%s: bad parameter order, subvol_gen=%llu reloc_gen=%llu",
3810                         __func__,
3811                         btrfs_node_ptr_generation(subvol_parent, subvol_slot),
3812                         btrfs_node_ptr_generation(reloc_parent, reloc_slot));
3813                 return -EUCLEAN;
3814         }
3815 
3816         block = kmalloc(sizeof(*block), GFP_NOFS);
3817         if (!block) {
3818                 ret = -ENOMEM;
3819                 goto out;
3820         }
3821 
3822         /*
3823          * @reloc_parent/slot is still before swap, while @block is going to
3824          * record the bytenr after swap, so we do the swap here.
3825          */
3826         block->subvol_bytenr = btrfs_node_blockptr(reloc_parent, reloc_slot);
3827         block->subvol_generation = btrfs_node_ptr_generation(reloc_parent,
3828                                                              reloc_slot);
3829         block->reloc_bytenr = btrfs_node_blockptr(subvol_parent, subvol_slot);
3830         block->reloc_generation = btrfs_node_ptr_generation(subvol_parent,
3831                                                             subvol_slot);
3832         block->last_snapshot = last_snapshot;
3833         block->level = level;
3834         if (bg->flags & BTRFS_BLOCK_GROUP_DATA)
3835                 block->trace_leaf = true;
3836         else
3837                 block->trace_leaf = false;
3838         btrfs_node_key_to_cpu(reloc_parent, &block->first_key, reloc_slot);
3839 
3840         /* Insert @block into @blocks */
3841         spin_lock(&blocks->lock);
3842         cur = &blocks->blocks[level].rb_node;
3843         while (*cur) {
3844                 struct btrfs_qgroup_swapped_block *entry;
3845 
3846                 parent = *cur;
3847                 entry = rb_entry(parent, struct btrfs_qgroup_swapped_block,
3848                                  node);
3849 
3850                 if (entry->subvol_bytenr < block->subvol_bytenr) {
3851                         cur = &(*cur)->rb_left;
3852                 } else if (entry->subvol_bytenr > block->subvol_bytenr) {
3853                         cur = &(*cur)->rb_right;
3854                 } else {
3855                         if (entry->subvol_generation !=
3856                                         block->subvol_generation ||
3857                             entry->reloc_bytenr != block->reloc_bytenr ||
3858                             entry->reloc_generation !=
3859                                         block->reloc_generation) {
3860                                 /*
3861                                  * Duplicated but mismatch entry found.
3862                                  * Shouldn't happen.
3863                                  *
3864                                  * Marking qgroup inconsistent should be enough
3865                                  * for end users.
3866                                  */
3867                                 WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
3868                                 ret = -EEXIST;
3869                         }
3870                         kfree(block);
3871                         goto out_unlock;
3872                 }
3873         }
3874         rb_link_node(&block->node, parent, cur);
3875         rb_insert_color(&block->node, &blocks->blocks[level]);
3876         blocks->swapped = true;
3877 out_unlock:
3878         spin_unlock(&blocks->lock);
3879 out:
3880         if (ret < 0)
3881                 fs_info->qgroup_flags |=
3882                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3883         return ret;
3884 }
3885 
3886 /*
3887  * Check if the tree block is a subtree root, and if so do the needed
3888  * delayed subtree trace for qgroup.
3889  *
3890  * This is called during btrfs_cow_block().
3891  */
3892 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
3893                                          struct btrfs_root *root,
3894                                          struct extent_buffer *subvol_eb)
3895 {
3896         struct btrfs_fs_info *fs_info = root->fs_info;
3897         struct btrfs_qgroup_swapped_blocks *blocks = &root->swapped_blocks;
3898         struct btrfs_qgroup_swapped_block *block;
3899         struct extent_buffer *reloc_eb = NULL;
3900         struct rb_node *node;
3901         bool found = false;
3902         bool swapped = false;
3903         int level = btrfs_header_level(subvol_eb);
3904         int ret = 0;
3905         int i;
3906 
3907         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
3908                 return 0;
3909         if (!is_fstree(root->root_key.objectid) || !root->reloc_root)
3910                 return 0;
3911 
3912         spin_lock(&blocks->lock);
3913         if (!blocks->swapped) {
3914                 spin_unlock(&blocks->lock);
3915                 return 0;
3916         }
3917         node = blocks->blocks[level].rb_node;
3918 
3919         while (node) {
3920                 block = rb_entry(node, struct btrfs_qgroup_swapped_block, node);
3921                 if (block->subvol_bytenr < subvol_eb->start) {
3922                         node = node->rb_left;
3923                 } else if (block->subvol_bytenr > subvol_eb->start) {
3924                         node = node->rb_right;
3925                 } else {
3926                         found = true;
3927                         break;
3928                 }
3929         }
3930         if (!found) {
3931                 spin_unlock(&blocks->lock);
3932                 goto out;
3933         }
3934         /* Found one, remove it from @blocks first and update blocks->swapped */
3935         rb_erase(&block->node, &blocks->blocks[level]);
3936         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
3937                 if (RB_EMPTY_ROOT(&blocks->blocks[i])) {
3938                         swapped = true;
3939                         break;
3940                 }
3941         }
3942         blocks->swapped = swapped;
3943         spin_unlock(&blocks->lock);
3944 
3945         /* Read out reloc subtree root */
3946         reloc_eb = read_tree_block(fs_info, block->reloc_bytenr,
3947                                    block->reloc_generation, block->level,
3948                                    &block->first_key);
3949         if (IS_ERR(reloc_eb)) {
3950                 ret = PTR_ERR(reloc_eb);
3951                 reloc_eb = NULL;
3952                 goto free_out;
3953         }
3954         if (!extent_buffer_uptodate(reloc_eb)) {
3955                 ret = -EIO;
3956                 goto free_out;
3957         }
3958 
3959         ret = qgroup_trace_subtree_swap(trans, reloc_eb, subvol_eb,
3960                         block->last_snapshot, block->trace_leaf);
3961 free_out:
3962         kfree(block);
3963         free_extent_buffer(reloc_eb);
3964 out:
3965         if (ret < 0) {
3966                 btrfs_err_rl(fs_info,
3967                              "failed to account subtree at bytenr %llu: %d",
3968                              subvol_eb->start, ret);
3969                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3970         }
3971         return ret;
3972 }
3973 

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