fs/btrfs/qgroup.c

   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/sched/mm.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 #include "block-group.h"
  25 #include "sysfs.h"
  26
  27 /* TODO XXX FIXME
  28  *  - subvol delete -> delete when ref goes to 0? delete limits also?
  29  *  - reorganize keys
  30  *  - compressed
  31  *  - sync
  32  *  - copy also limits on subvol creation
  33  *  - limit
  34  *  - caches for ulists
  35  *  - performance benchmarks
  36  *  - check all ioctl parameters
  37  */
  38
  39 /*
  40  * Helpers to access qgroup reservation
  41  *
  42  * Callers should ensure the lock context and type are valid
  43  */
  44
  45 static u64 qgroup_rsv_total(const struct btrfs_qgroup *qgroup)
  46 {
  47         u64 ret = 0;
  48         int i;
  49
  50         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
  51                 ret += qgroup->rsv.values[i];
  52
  53         return ret;
  54 }
  55
  56 #ifdef CONFIG_BTRFS_DEBUG
  57 static const char *qgroup_rsv_type_str(enum btrfs_qgroup_rsv_type type)
  58 {
  59         if (type == BTRFS_QGROUP_RSV_DATA)
  60                 return "data";
  61         if (type == BTRFS_QGROUP_RSV_META_PERTRANS)
  62                 return "meta_pertrans";
  63         if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
  64                 return "meta_prealloc";
  65         return NULL;
  66 }
  67 #endif
  68
  69 static void qgroup_rsv_add(struct btrfs_fs_info *fs_info,
  70                            struct btrfs_qgroup *qgroup, u64 num_bytes,
  71                            enum btrfs_qgroup_rsv_type type)
  72 {
  73         trace_qgroup_update_reserve(fs_info, qgroup, num_bytes, type);
  74         qgroup->rsv.values[type] += num_bytes;
  75 }
  76
  77 static void qgroup_rsv_release(struct btrfs_fs_info *fs_info,
  78                                struct btrfs_qgroup *qgroup, u64 num_bytes,
  79                                enum btrfs_qgroup_rsv_type type)
  80 {
  81         trace_qgroup_update_reserve(fs_info, qgroup, -(s64)num_bytes, type);
  82         if (qgroup->rsv.values[type] >= num_bytes) {
  83                 qgroup->rsv.values[type] -= num_bytes;
  84                 return;
  85         }
  86 #ifdef CONFIG_BTRFS_DEBUG
  87         WARN_RATELIMIT(1,
  88                 "qgroup %llu %s reserved space underflow, have %llu to free %llu",
  89                 qgroup->qgroupid, qgroup_rsv_type_str(type),
  90                 qgroup->rsv.values[type], num_bytes);
  91 #endif
  92         qgroup->rsv.values[type] = 0;
  93 }
  94
  95 static void qgroup_rsv_add_by_qgroup(struct btrfs_fs_info *fs_info,
  96                                      struct btrfs_qgroup *dest,
  97                                      struct btrfs_qgroup *src)
  98 {
  99         int i;
 100
 101         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
 102                 qgroup_rsv_add(fs_info, dest, src->rsv.values[i], i);
 103 }
 104
 105 static void qgroup_rsv_release_by_qgroup(struct btrfs_fs_info *fs_info,
 106                                          struct btrfs_qgroup *dest,
 107                                           struct btrfs_qgroup *src)
 108 {
 109         int i;
 110
 111         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
 112                 qgroup_rsv_release(fs_info, dest, src->rsv.values[i], i);
 113 }
 114
 115 static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,
 116                                            int mod)
 117 {
 118         if (qg->old_refcnt < seq)
 119                 qg->old_refcnt = seq;
 120         qg->old_refcnt += mod;
 121 }
 122
 123 static void btrfs_qgroup_update_new_refcnt(struct btrfs_qgroup *qg, u64 seq,
 124                                            int mod)
 125 {
 126         if (qg->new_refcnt < seq)
 127                 qg->new_refcnt = seq;
 128         qg->new_refcnt += mod;
 129 }
 130
 131 static inline u64 btrfs_qgroup_get_old_refcnt(struct btrfs_qgroup *qg, u64 seq)
 132 {
 133         if (qg->old_refcnt < seq)
 134                 return 0;
 135         return qg->old_refcnt - seq;
 136 }
 137
 138 static inline u64 btrfs_qgroup_get_new_refcnt(struct btrfs_qgroup *qg, u64 seq)
 139 {
 140         if (qg->new_refcnt < seq)
 141                 return 0;
 142         return qg->new_refcnt - seq;
 143 }
 144
 145 /*
 146  * glue structure to represent the relations between qgroups.
 147  */
 148 struct btrfs_qgroup_list {
 149         struct list_head next_group;
 150         struct list_head next_member;
 151         struct btrfs_qgroup *group;
 152         struct btrfs_qgroup *member;
 153 };
 154
 155 static inline u64 qgroup_to_aux(struct btrfs_qgroup *qg)
 156 {
 157         return (u64)(uintptr_t)qg;
 158 }
 159
 160 static inline struct btrfs_qgroup* unode_aux_to_qgroup(struct ulist_node *n)
 161 {
 162         return (struct btrfs_qgroup *)(uintptr_t)n->aux;
 163 }
 164
 165 static int
 166 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
 167                    int init_flags);
 168 static void qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info);
 169
 170 /* must be called with qgroup_ioctl_lock held */
 171 static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
 172                                            u64 qgroupid)
 173 {
 174         struct rb_node *n = fs_info->qgroup_tree.rb_node;
 175         struct btrfs_qgroup *qgroup;
 176
 177         while (n) {
 178                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
 179                 if (qgroup->qgroupid < qgroupid)
 180                         n = n->rb_left;
 181                 else if (qgroup->qgroupid > qgroupid)
 182                         n = n->rb_right;
 183                 else
 184                         return qgroup;
 185         }
 186         return NULL;
 187 }
 188
 189 /* must be called with qgroup_lock held */
 190 static struct btrfs_qgroup *add_qgroup_rb(struct btrfs_fs_info *fs_info,
 191                                           u64 qgroupid)
 192 {
 193         struct rb_node **p = &fs_info->qgroup_tree.rb_node;
 194         struct rb_node *parent = NULL;
 195         struct btrfs_qgroup *qgroup;
 196
 197         while (*p) {
 198                 parent = *p;
 199                 qgroup = rb_entry(parent, struct btrfs_qgroup, node);
 200
 201                 if (qgroup->qgroupid < qgroupid)
 202                         p = &(*p)->rb_left;
 203                 else if (qgroup->qgroupid > qgroupid)
 204                         p = &(*p)->rb_right;
 205                 else
 206                         return qgroup;
 207         }
 208
 209         qgroup = kzalloc(sizeof(*qgroup), GFP_ATOMIC);
 210         if (!qgroup)
 211                 return ERR_PTR(-ENOMEM);
 212
 213         qgroup->qgroupid = qgroupid;
 214         INIT_LIST_HEAD(&qgroup->groups);
 215         INIT_LIST_HEAD(&qgroup->members);
 216         INIT_LIST_HEAD(&qgroup->dirty);
 217
 218         rb_link_node(&qgroup->node, parent, p);
 219         rb_insert_color(&qgroup->node, &fs_info->qgroup_tree);
 220
 221         return qgroup;
 222 }
 223
 224 static void __del_qgroup_rb(struct btrfs_fs_info *fs_info,
 225                             struct btrfs_qgroup *qgroup)
 226 {
 227         struct btrfs_qgroup_list *list;
 228
 229         list_del(&qgroup->dirty);
 230         while (!list_empty(&qgroup->groups)) {
 231                 list = list_first_entry(&qgroup->groups,
 232                                         struct btrfs_qgroup_list, next_group);
 233                 list_del(&list->next_group);
 234                 list_del(&list->next_member);
 235                 kfree(list);
 236         }
 237
 238         while (!list_empty(&qgroup->members)) {
 239                 list = list_first_entry(&qgroup->members,
 240                                         struct btrfs_qgroup_list, next_member);
 241                 list_del(&list->next_group);
 242                 list_del(&list->next_member);
 243                 kfree(list);
 244         }
 245 }
 246
 247 /* must be called with qgroup_lock held */
 248 static int del_qgroup_rb(struct btrfs_fs_info *fs_info, u64 qgroupid)
 249 {
 250         struct btrfs_qgroup *qgroup = find_qgroup_rb(fs_info, qgroupid);
 251
 252         if (!qgroup)
 253                 return -ENOENT;
 254
 255         rb_erase(&qgroup->node, &fs_info->qgroup_tree);
 256         __del_qgroup_rb(fs_info, qgroup);
 257         return 0;
 258 }
 259
 260 /* must be called with qgroup_lock held */
 261 static int add_relation_rb(struct btrfs_fs_info *fs_info,
 262                            u64 memberid, u64 parentid)
 263 {
 264         struct btrfs_qgroup *member;
 265         struct btrfs_qgroup *parent;
 266         struct btrfs_qgroup_list *list;
 267
 268         member = find_qgroup_rb(fs_info, memberid);
 269         parent = find_qgroup_rb(fs_info, parentid);
 270         if (!member || !parent)
 271                 return -ENOENT;
 272
 273         list = kzalloc(sizeof(*list), GFP_ATOMIC);
 274         if (!list)
 275                 return -ENOMEM;
 276
 277         list->group = parent;
 278         list->member = member;
 279         list_add_tail(&list->next_group, &member->groups);
 280         list_add_tail(&list->next_member, &parent->members);
 281
 282         return 0;
 283 }
 284
 285 /* must be called with qgroup_lock held */
 286 static int del_relation_rb(struct btrfs_fs_info *fs_info,
 287                            u64 memberid, u64 parentid)
 288 {
 289         struct btrfs_qgroup *member;
 290         struct btrfs_qgroup *parent;
 291         struct btrfs_qgroup_list *list;
 292
 293         member = find_qgroup_rb(fs_info, memberid);
 294         parent = find_qgroup_rb(fs_info, parentid);
 295         if (!member || !parent)
 296                 return -ENOENT;
 297
 298         list_for_each_entry(list, &member->groups, next_group) {
 299                 if (list->group == parent) {
 300                         list_del(&list->next_group);
 301                         list_del(&list->next_member);
 302                         kfree(list);
 303                         return 0;
 304                 }
 305         }
 306         return -ENOENT;
 307 }
 308
 309 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 310 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
 311                                u64 rfer, u64 excl)
 312 {
 313         struct btrfs_qgroup *qgroup;
 314
 315         qgroup = find_qgroup_rb(fs_info, qgroupid);
 316         if (!qgroup)
 317                 return -EINVAL;
 318         if (qgroup->rfer != rfer || qgroup->excl != excl)
 319                 return -EINVAL;
 320         return 0;
 321 }
 322 #endif
 323
 324 /*
 325  * The full config is read in one go, only called from open_ctree()
 326  * It doesn't use any locking, as at this point we're still single-threaded
 327  */
 328 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
 329 {
 330         struct btrfs_key key;
 331         struct btrfs_key found_key;
 332         struct btrfs_root *quota_root = fs_info->quota_root;
 333         struct btrfs_path *path = NULL;
 334         struct extent_buffer *l;
 335         int slot;
 336         int ret = 0;
 337         u64 flags = 0;
 338         u64 rescan_progress = 0;
 339
 340         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
 341                 return 0;
 342
 343         fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
 344         if (!fs_info->qgroup_ulist) {
 345                 ret = -ENOMEM;
 346                 goto out;
 347         }
 348
 349         path = btrfs_alloc_path();
 350         if (!path) {
 351                 ret = -ENOMEM;
 352                 goto out;
 353         }
 354
 355         ret = btrfs_sysfs_add_qgroups(fs_info);
 356         if (ret < 0)
 357                 goto out;
 358         /* default this to quota off, in case no status key is found */
 359         fs_info->qgroup_flags = 0;
 360
 361         /*
 362          * pass 1: read status, all qgroup infos and limits
 363          */
 364         key.objectid = 0;
 365         key.type = 0;
 366         key.offset = 0;
 367         ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 1);
 368         if (ret)
 369                 goto out;
 370
 371         while (1) {
 372                 struct btrfs_qgroup *qgroup;
 373
 374                 slot = path->slots[0];
 375                 l = path->nodes[0];
 376                 btrfs_item_key_to_cpu(l, &found_key, slot);
 377
 378                 if (found_key.type == BTRFS_QGROUP_STATUS_KEY) {
 379                         struct btrfs_qgroup_status_item *ptr;
 380
 381                         ptr = btrfs_item_ptr(l, slot,
 382                                              struct btrfs_qgroup_status_item);
 383
 384                         if (btrfs_qgroup_status_version(l, ptr) !=
 385                             BTRFS_QGROUP_STATUS_VERSION) {
 386                                 btrfs_err(fs_info,
 387                                  "old qgroup version, quota disabled");
 388                                 goto out;
 389                         }
 390                         if (btrfs_qgroup_status_generation(l, ptr) !=
 391                             fs_info->generation) {
 392                                 flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
 393                                 btrfs_err(fs_info,
 394                                         "qgroup generation mismatch, marked as inconsistent");
 395                         }
 396                         fs_info->qgroup_flags = btrfs_qgroup_status_flags(l,
 397                                                                           ptr);
 398                         rescan_progress = btrfs_qgroup_status_rescan(l, ptr);
 399                         goto next1;
 400                 }
 401
 402                 if (found_key.type != BTRFS_QGROUP_INFO_KEY &&
 403                     found_key.type != BTRFS_QGROUP_LIMIT_KEY)
 404                         goto next1;
 405
 406                 qgroup = find_qgroup_rb(fs_info, found_key.offset);
 407                 if ((qgroup && found_key.type == BTRFS_QGROUP_INFO_KEY) ||
 408                     (!qgroup && found_key.type == BTRFS_QGROUP_LIMIT_KEY)) {
 409                         btrfs_err(fs_info, "inconsistent qgroup config");
 410                         flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
 411                 }
 412                 if (!qgroup) {
 413                         qgroup = add_qgroup_rb(fs_info, found_key.offset);
 414                         if (IS_ERR(qgroup)) {
 415                                 ret = PTR_ERR(qgroup);
 416                                 goto out;
 417                         }
 418                 }
 419                 ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
 420                 if (ret < 0)
 421                         goto out;
 422
 423                 switch (found_key.type) {
 424                 case BTRFS_QGROUP_INFO_KEY: {
 425                         struct btrfs_qgroup_info_item *ptr;
 426
 427                         ptr = btrfs_item_ptr(l, slot,
 428                                              struct btrfs_qgroup_info_item);
 429                         qgroup->rfer = btrfs_qgroup_info_rfer(l, ptr);
 430                         qgroup->rfer_cmpr = btrfs_qgroup_info_rfer_cmpr(l, ptr);
 431                         qgroup->excl = btrfs_qgroup_info_excl(l, ptr);
 432                         qgroup->excl_cmpr = btrfs_qgroup_info_excl_cmpr(l, ptr);
 433                         /* generation currently unused */
 434                         break;
 435                 }
 436                 case BTRFS_QGROUP_LIMIT_KEY: {
 437                         struct btrfs_qgroup_limit_item *ptr;
 438
 439                         ptr = btrfs_item_ptr(l, slot,
 440                                              struct btrfs_qgroup_limit_item);
 441                         qgroup->lim_flags = btrfs_qgroup_limit_flags(l, ptr);
 442                         qgroup->max_rfer = btrfs_qgroup_limit_max_rfer(l, ptr);
 443                         qgroup->max_excl = btrfs_qgroup_limit_max_excl(l, ptr);
 444                         qgroup->rsv_rfer = btrfs_qgroup_limit_rsv_rfer(l, ptr);
 445                         qgroup->rsv_excl = btrfs_qgroup_limit_rsv_excl(l, ptr);
 446                         break;
 447                 }
 448                 }
 449 next1:
 450                 ret = btrfs_next_item(quota_root, path);
 451                 if (ret < 0)
 452                         goto out;
 453                 if (ret)
 454                         break;
 455         }
 456         btrfs_release_path(path);
 457
 458         /*
 459          * pass 2: read all qgroup relations
 460          */
 461         key.objectid = 0;
 462         key.type = BTRFS_QGROUP_RELATION_KEY;
 463         key.offset = 0;
 464         ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 0);
 465         if (ret)
 466                 goto out;
 467         while (1) {
 468                 slot = path->slots[0];
 469                 l = path->nodes[0];
 470                 btrfs_item_key_to_cpu(l, &found_key, slot);
 471
 472                 if (found_key.type != BTRFS_QGROUP_RELATION_KEY)
 473                         goto next2;
 474
 475                 if (found_key.objectid > found_key.offset) {
 476                         /* parent <- member, not needed to build config */
 477                         /* FIXME should we omit the key completely? */
 478                         goto next2;
 479                 }
 480
 481                 ret = add_relation_rb(fs_info, found_key.objectid,
 482                                       found_key.offset);
 483                 if (ret == -ENOENT) {
 484                         btrfs_warn(fs_info,
 485                                 "orphan qgroup relation 0x%llx->0x%llx",
 486                                 found_key.objectid, found_key.offset);
 487                         ret = 0;        /* ignore the error */
 488                 }
 489                 if (ret)
 490                         goto out;
 491 next2:
 492                 ret = btrfs_next_item(quota_root, path);
 493                 if (ret < 0)
 494                         goto out;
 495                 if (ret)
 496                         break;
 497         }
 498 out:
 499         btrfs_free_path(path);
 500         fs_info->qgroup_flags |= flags;
 501         if (!(fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON))
 502                 clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
 503         else if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN &&
 504                  ret >= 0)
 505                 ret = qgroup_rescan_init(fs_info, rescan_progress, 0);
 506
 507         if (ret < 0) {
 508                 ulist_free(fs_info->qgroup_ulist);
 509                 fs_info->qgroup_ulist = NULL;
 510                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
 511                 btrfs_sysfs_del_qgroups(fs_info);
 512         }
 513
 514         return ret < 0 ? ret : 0;
 515 }
 516
 517 /*
 518  * Called in close_ctree() when quota is still enabled.  This verifies we don't
 519  * leak some reserved space.
 520  *
 521  * Return false if no reserved space is left.
 522  * Return true if some reserved space is leaked.
 523  */
 524 bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info)
 525 {
 526         struct rb_node *node;
 527         bool ret = false;
 528
 529         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
 530                 return ret;
 531         /*
 532          * Since we're unmounting, there is no race and no need to grab qgroup
 533          * lock.  And here we don't go post-order to provide a more user
 534          * friendly sorted result.
 535          */
 536         for (node = rb_first(&fs_info->qgroup_tree); node; node = rb_next(node)) {
 537                 struct btrfs_qgroup *qgroup;
 538                 int i;
 539
 540                 qgroup = rb_entry(node, struct btrfs_qgroup, node);
 541                 for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++) {
 542                         if (qgroup->rsv.values[i]) {
 543                                 ret = true;
 544                                 btrfs_warn(fs_info,
 545                 "qgroup %hu/%llu has unreleased space, type %d rsv %llu",
 546                                    btrfs_qgroup_level(qgroup->qgroupid),
 547                                    btrfs_qgroup_subvolid(qgroup->qgroupid),
 548                                    i, qgroup->rsv.values[i]);
 549                         }
 550                 }
 551         }
 552         return ret;
 553 }
 554
 555 /*
 556  * This is called from close_ctree() or open_ctree() or btrfs_quota_disable(),
 557  * first two are in single-threaded paths.And for the third one, we have set
 558  * quota_root to be null with qgroup_lock held before, so it is safe to clean
 559  * up the in-memory structures without qgroup_lock held.
 560  */
 561 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
 562 {
 563         struct rb_node *n;
 564         struct btrfs_qgroup *qgroup;
 565
 566         while ((n = rb_first(&fs_info->qgroup_tree))) {
 567                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
 568                 rb_erase(n, &fs_info->qgroup_tree);
 569                 __del_qgroup_rb(fs_info, qgroup);
 570                 btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
 571                 kfree(qgroup);
 572         }
 573         /*
 574          * We call btrfs_free_qgroup_config() when unmounting
 575          * filesystem and disabling quota, so we set qgroup_ulist
 576          * to be null here to avoid double free.
 577          */
 578         ulist_free(fs_info->qgroup_ulist);
 579         fs_info->qgroup_ulist = NULL;
 580         btrfs_sysfs_del_qgroups(fs_info);
 581 }
 582
 583 static int add_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
 584                                     u64 dst)
 585 {
 586         int ret;
 587         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 588         struct btrfs_path *path;
 589         struct btrfs_key key;
 590
 591         path = btrfs_alloc_path();
 592         if (!path)
 593                 return -ENOMEM;
 594
 595         key.objectid = src;
 596         key.type = BTRFS_QGROUP_RELATION_KEY;
 597         key.offset = dst;
 598
 599         ret = btrfs_insert_empty_item(trans, quota_root, path, &key, 0);
 600
 601         btrfs_mark_buffer_dirty(path->nodes[0]);
 602
 603         btrfs_free_path(path);
 604         return ret;
 605 }
 606
 607 static int del_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
 608                                     u64 dst)
 609 {
 610         int ret;
 611         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 612         struct btrfs_path *path;
 613         struct btrfs_key key;
 614
 615         path = btrfs_alloc_path();
 616         if (!path)
 617                 return -ENOMEM;
 618
 619         key.objectid = src;
 620         key.type = BTRFS_QGROUP_RELATION_KEY;
 621         key.offset = dst;
 622
 623         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
 624         if (ret < 0)
 625                 goto out;
 626
 627         if (ret > 0) {
 628                 ret = -ENOENT;
 629                 goto out;
 630         }
 631
 632         ret = btrfs_del_item(trans, quota_root, path);
 633 out:
 634         btrfs_free_path(path);
 635         return ret;
 636 }
 637
 638 static int add_qgroup_item(struct btrfs_trans_handle *trans,
 639                            struct btrfs_root *quota_root, u64 qgroupid)
 640 {
 641         int ret;
 642         struct btrfs_path *path;
 643         struct btrfs_qgroup_info_item *qgroup_info;
 644         struct btrfs_qgroup_limit_item *qgroup_limit;
 645         struct extent_buffer *leaf;
 646         struct btrfs_key key;
 647
 648         if (btrfs_is_testing(quota_root->fs_info))
 649                 return 0;
 650
 651         path = btrfs_alloc_path();
 652         if (!path)
 653                 return -ENOMEM;
 654
 655         key.objectid = 0;
 656         key.type = BTRFS_QGROUP_INFO_KEY;
 657         key.offset = qgroupid;
 658
 659         /*
 660          * Avoid a transaction abort by catching -EEXIST here. In that
 661          * case, we proceed by re-initializing the existing structure
 662          * on disk.
 663          */
 664
 665         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
 666                                       sizeof(*qgroup_info));
 667         if (ret && ret != -EEXIST)
 668                 goto out;
 669
 670         leaf = path->nodes[0];
 671         qgroup_info = btrfs_item_ptr(leaf, path->slots[0],
 672                                  struct btrfs_qgroup_info_item);
 673         btrfs_set_qgroup_info_generation(leaf, qgroup_info, trans->transid);
 674         btrfs_set_qgroup_info_rfer(leaf, qgroup_info, 0);
 675         btrfs_set_qgroup_info_rfer_cmpr(leaf, qgroup_info, 0);
 676         btrfs_set_qgroup_info_excl(leaf, qgroup_info, 0);
 677         btrfs_set_qgroup_info_excl_cmpr(leaf, qgroup_info, 0);
 678
 679         btrfs_mark_buffer_dirty(leaf);
 680
 681         btrfs_release_path(path);
 682
 683         key.type = BTRFS_QGROUP_LIMIT_KEY;
 684         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
 685                                       sizeof(*qgroup_limit));
 686         if (ret && ret != -EEXIST)
 687                 goto out;
 688
 689         leaf = path->nodes[0];
 690         qgroup_limit = btrfs_item_ptr(leaf, path->slots[0],
 691                                   struct btrfs_qgroup_limit_item);
 692         btrfs_set_qgroup_limit_flags(leaf, qgroup_limit, 0);
 693         btrfs_set_qgroup_limit_max_rfer(leaf, qgroup_limit, 0);
 694         btrfs_set_qgroup_limit_max_excl(leaf, qgroup_limit, 0);
 695         btrfs_set_qgroup_limit_rsv_rfer(leaf, qgroup_limit, 0);
 696         btrfs_set_qgroup_limit_rsv_excl(leaf, qgroup_limit, 0);
 697
 698         btrfs_mark_buffer_dirty(leaf);
 699
 700         ret = 0;
 701 out:
 702         btrfs_free_path(path);
 703         return ret;
 704 }
 705
 706 static int del_qgroup_item(struct btrfs_trans_handle *trans, u64 qgroupid)
 707 {
 708         int ret;
 709         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 710         struct btrfs_path *path;
 711         struct btrfs_key key;
 712
 713         path = btrfs_alloc_path();
 714         if (!path)
 715                 return -ENOMEM;
 716
 717         key.objectid = 0;
 718         key.type = BTRFS_QGROUP_INFO_KEY;
 719         key.offset = qgroupid;
 720         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
 721         if (ret < 0)
 722                 goto out;
 723
 724         if (ret > 0) {
 725                 ret = -ENOENT;
 726                 goto out;
 727         }
 728
 729         ret = btrfs_del_item(trans, quota_root, path);
 730         if (ret)
 731                 goto out;
 732
 733         btrfs_release_path(path);
 734
 735         key.type = BTRFS_QGROUP_LIMIT_KEY;
 736         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
 737         if (ret < 0)
 738                 goto out;
 739
 740         if (ret > 0) {
 741                 ret = -ENOENT;
 742                 goto out;
 743         }
 744
 745         ret = btrfs_del_item(trans, quota_root, path);
 746
 747 out:
 748         btrfs_free_path(path);
 749         return ret;
 750 }
 751
 752 static int update_qgroup_limit_item(struct btrfs_trans_handle *trans,
 753                                     struct btrfs_qgroup *qgroup)
 754 {
 755         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 756         struct btrfs_path *path;
 757         struct btrfs_key key;
 758         struct extent_buffer *l;
 759         struct btrfs_qgroup_limit_item *qgroup_limit;
 760         int ret;
 761         int slot;
 762
 763         key.objectid = 0;
 764         key.type = BTRFS_QGROUP_LIMIT_KEY;
 765         key.offset = qgroup->qgroupid;
 766
 767         path = btrfs_alloc_path();
 768         if (!path)
 769                 return -ENOMEM;
 770
 771         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
 772         if (ret > 0)
 773                 ret = -ENOENT;
 774
 775         if (ret)
 776                 goto out;
 777
 778         l = path->nodes[0];
 779         slot = path->slots[0];
 780         qgroup_limit = btrfs_item_ptr(l, slot, struct btrfs_qgroup_limit_item);
 781         btrfs_set_qgroup_limit_flags(l, qgroup_limit, qgroup->lim_flags);
 782         btrfs_set_qgroup_limit_max_rfer(l, qgroup_limit, qgroup->max_rfer);
 783         btrfs_set_qgroup_limit_max_excl(l, qgroup_limit, qgroup->max_excl);
 784         btrfs_set_qgroup_limit_rsv_rfer(l, qgroup_limit, qgroup->rsv_rfer);
 785         btrfs_set_qgroup_limit_rsv_excl(l, qgroup_limit, qgroup->rsv_excl);
 786
 787         btrfs_mark_buffer_dirty(l);
 788
 789 out:
 790         btrfs_free_path(path);
 791         return ret;
 792 }
 793
 794 static int update_qgroup_info_item(struct btrfs_trans_handle *trans,
 795                                    struct btrfs_qgroup *qgroup)
 796 {
 797         struct btrfs_fs_info *fs_info = trans->fs_info;
 798         struct btrfs_root *quota_root = fs_info->quota_root;
 799         struct btrfs_path *path;
 800         struct btrfs_key key;
 801         struct extent_buffer *l;
 802         struct btrfs_qgroup_info_item *qgroup_info;
 803         int ret;
 804         int slot;
 805
 806         if (btrfs_is_testing(fs_info))
 807                 return 0;
 808
 809         key.objectid = 0;
 810         key.type = BTRFS_QGROUP_INFO_KEY;
 811         key.offset = qgroup->qgroupid;
 812
 813         path = btrfs_alloc_path();
 814         if (!path)
 815                 return -ENOMEM;
 816
 817         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
 818         if (ret > 0)
 819                 ret = -ENOENT;
 820
 821         if (ret)
 822                 goto out;
 823
 824         l = path->nodes[0];
 825         slot = path->slots[0];
 826         qgroup_info = btrfs_item_ptr(l, slot, struct btrfs_qgroup_info_item);
 827         btrfs_set_qgroup_info_generation(l, qgroup_info, trans->transid);
 828         btrfs_set_qgroup_info_rfer(l, qgroup_info, qgroup->rfer);
 829         btrfs_set_qgroup_info_rfer_cmpr(l, qgroup_info, qgroup->rfer_cmpr);
 830         btrfs_set_qgroup_info_excl(l, qgroup_info, qgroup->excl);
 831         btrfs_set_qgroup_info_excl_cmpr(l, qgroup_info, qgroup->excl_cmpr);
 832
 833         btrfs_mark_buffer_dirty(l);
 834
 835 out:
 836         btrfs_free_path(path);
 837         return ret;
 838 }
 839
 840 static int update_qgroup_status_item(struct btrfs_trans_handle *trans)
 841 {
 842         struct btrfs_fs_info *fs_info = trans->fs_info;
 843         struct btrfs_root *quota_root = fs_info->quota_root;
 844         struct btrfs_path *path;
 845         struct btrfs_key key;
 846         struct extent_buffer *l;
 847         struct btrfs_qgroup_status_item *ptr;
 848         int ret;
 849         int slot;
 850
 851         key.objectid = 0;
 852         key.type = BTRFS_QGROUP_STATUS_KEY;
 853         key.offset = 0;
 854
 855         path = btrfs_alloc_path();
 856         if (!path)
 857                 return -ENOMEM;
 858
 859         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
 860         if (ret > 0)
 861                 ret = -ENOENT;
 862
 863         if (ret)
 864                 goto out;
 865
 866         l = path->nodes[0];
 867         slot = path->slots[0];
 868         ptr = btrfs_item_ptr(l, slot, struct btrfs_qgroup_status_item);
 869         btrfs_set_qgroup_status_flags(l, ptr, fs_info->qgroup_flags);
 870         btrfs_set_qgroup_status_generation(l, ptr, trans->transid);
 871         btrfs_set_qgroup_status_rescan(l, ptr,
 872                                 fs_info->qgroup_rescan_progress.objectid);
 873
 874         btrfs_mark_buffer_dirty(l);
 875
 876 out:
 877         btrfs_free_path(path);
 878         return ret;
 879 }
 880
 881 /*
 882  * called with qgroup_lock held
 883  */
 884 static int btrfs_clean_quota_tree(struct btrfs_trans_handle *trans,
 885                                   struct btrfs_root *root)
 886 {
 887         struct btrfs_path *path;
 888         struct btrfs_key key;
 889         struct extent_buffer *leaf = NULL;
 890         int ret;
 891         int nr = 0;
 892
 893         path = btrfs_alloc_path();
 894         if (!path)
 895                 return -ENOMEM;
 896
 897         path->leave_spinning = 1;
 898
 899         key.objectid = 0;
 900         key.offset = 0;
 901         key.type = 0;
 902
 903         while (1) {
 904                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 905                 if (ret < 0)
 906                         goto out;
 907                 leaf = path->nodes[0];
 908                 nr = btrfs_header_nritems(leaf);
 909                 if (!nr)
 910                         break;
 911                 /*
 912                  * delete the leaf one by one
 913                  * since the whole tree is going
 914                  * to be deleted.
 915                  */
 916                 path->slots[0] = 0;
 917                 ret = btrfs_del_items(trans, root, path, 0, nr);
 918                 if (ret)
 919                         goto out;
 920
 921                 btrfs_release_path(path);
 922         }
 923         ret = 0;
 924 out:
 925         btrfs_free_path(path);
 926         return ret;
 927 }
 928
 929 int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
 930 {
 931         struct btrfs_root *quota_root;
 932         struct btrfs_root *tree_root = fs_info->tree_root;
 933         struct btrfs_path *path = NULL;
 934         struct btrfs_qgroup_status_item *ptr;
 935         struct extent_buffer *leaf;
 936         struct btrfs_key key;
 937         struct btrfs_key found_key;
 938         struct btrfs_qgroup *qgroup = NULL;
 939         struct btrfs_trans_handle *trans = NULL;
 940         struct ulist *ulist = NULL;
 941         int ret = 0;
 942         int slot;
 943
 944         /*
 945          * We need to have subvol_sem write locked, to prevent races between
 946          * concurrent tasks trying to enable quotas, because we will unlock
 947          * and relock qgroup_ioctl_lock before setting fs_info->quota_root
 948          * and before setting BTRFS_FS_QUOTA_ENABLED.
 949          */
 950         lockdep_assert_held_write(&fs_info->subvol_sem);
 951
 952         mutex_lock(&fs_info->qgroup_ioctl_lock);
 953         if (fs_info->quota_root)
 954                 goto out;
 955
 956         ulist = ulist_alloc(GFP_KERNEL);
 957         if (!ulist) {
 958                 ret = -ENOMEM;
 959                 goto out;
 960         }
 961
 962         ret = btrfs_sysfs_add_qgroups(fs_info);
 963         if (ret < 0)
 964                 goto out;
 965
 966         /*
 967          * Unlock qgroup_ioctl_lock before starting the transaction. This is to
 968          * avoid lock acquisition inversion problems (reported by lockdep) between
 969          * qgroup_ioctl_lock and the vfs freeze semaphores, acquired when we
 970          * start a transaction.
 971          * After we started the transaction lock qgroup_ioctl_lock again and
 972          * check if someone else created the quota root in the meanwhile. If so,
 973          * just return success and release the transaction handle.
 974          *
 975          * Also we don't need to worry about someone else calling
 976          * btrfs_sysfs_add_qgroups() after we unlock and getting an error because
 977          * that function returns 0 (success) when the sysfs entries already exist.
 978          */
 979         mutex_unlock(&fs_info->qgroup_ioctl_lock);
 980
 981         /*
 982          * 1 for quota root item
 983          * 1 for BTRFS_QGROUP_STATUS item
 984          *
 985          * Yet we also need 2*n items for a QGROUP_INFO/QGROUP_LIMIT items
 986          * per subvolume. However those are not currently reserved since it
 987          * would be a lot of overkill.
 988          */
 989         trans = btrfs_start_transaction(tree_root, 2);
 990
 991         mutex_lock(&fs_info->qgroup_ioctl_lock);
 992         if (IS_ERR(trans)) {
 993                 ret = PTR_ERR(trans);
 994                 trans = NULL;
 995                 goto out;
 996         }
 997
 998         if (fs_info->quota_root)
 999                 goto out;
1000
1001         fs_info->qgroup_ulist = ulist;
1002         ulist = NULL;
1003
1004         /*
1005          * initially create the quota tree
1006          */
1007         quota_root = btrfs_create_tree(trans, BTRFS_QUOTA_TREE_OBJECTID);
1008         if (IS_ERR(quota_root)) {
1009                 ret =  PTR_ERR(quota_root);
1010                 btrfs_abort_transaction(trans, ret);
1011                 goto out;
1012         }
1013
1014         path = btrfs_alloc_path();
1015         if (!path) {
1016                 ret = -ENOMEM;
1017                 btrfs_abort_transaction(trans, ret);
1018                 goto out_free_root;
1019         }
1020
1021         key.objectid = 0;
1022         key.type = BTRFS_QGROUP_STATUS_KEY;
1023         key.offset = 0;
1024
1025         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
1026                                       sizeof(*ptr));
1027         if (ret) {
1028                 btrfs_abort_transaction(trans, ret);
1029                 goto out_free_path;
1030         }
1031
1032         leaf = path->nodes[0];
1033         ptr = btrfs_item_ptr(leaf, path->slots[0],
1034                                  struct btrfs_qgroup_status_item);
1035         btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
1036         btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
1037         fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON |
1038                                 BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1039         btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags);
1040         btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
1041
1042         btrfs_mark_buffer_dirty(leaf);
1043
1044         key.objectid = 0;
1045         key.type = BTRFS_ROOT_REF_KEY;
1046         key.offset = 0;
1047
1048         btrfs_release_path(path);
1049         ret = btrfs_search_slot_for_read(tree_root, &key, path, 1, 0);
1050         if (ret > 0)
1051                 goto out_add_root;
1052         if (ret < 0) {
1053                 btrfs_abort_transaction(trans, ret);
1054                 goto out_free_path;
1055         }
1056
1057         while (1) {
1058                 slot = path->slots[0];
1059                 leaf = path->nodes[0];
1060                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1061
1062                 if (found_key.type == BTRFS_ROOT_REF_KEY) {
1063
1064                         /* Release locks on tree_root before we access quota_root */
1065                         btrfs_release_path(path);
1066
1067                         ret = add_qgroup_item(trans, quota_root,
1068                                               found_key.offset);
1069                         if (ret) {
1070                                 btrfs_abort_transaction(trans, ret);
1071                                 goto out_free_path;
1072                         }
1073
1074                         qgroup = add_qgroup_rb(fs_info, found_key.offset);
1075                         if (IS_ERR(qgroup)) {
1076                                 ret = PTR_ERR(qgroup);
1077                                 btrfs_abort_transaction(trans, ret);
1078                                 goto out_free_path;
1079                         }
1080                         ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1081                         if (ret < 0) {
1082                                 btrfs_abort_transaction(trans, ret);
1083                                 goto out_free_path;
1084                         }
1085                         ret = btrfs_search_slot_for_read(tree_root, &found_key,
1086                                                          path, 1, 0);
1087                         if (ret < 0) {
1088                                 btrfs_abort_transaction(trans, ret);
1089                                 goto out_free_path;
1090                         }
1091                         if (ret > 0) {
1092                                 /*
1093                                  * Shouldn't happen, but in case it does we
1094                                  * don't need to do the btrfs_next_item, just
1095                                  * continue.
1096                                  */
1097                                 continue;
1098                         }
1099                 }
1100                 ret = btrfs_next_item(tree_root, path);
1101                 if (ret < 0) {
1102                         btrfs_abort_transaction(trans, ret);
1103                         goto out_free_path;
1104                 }
1105                 if (ret)
1106                         break;
1107         }
1108
1109 out_add_root:
1110         btrfs_release_path(path);
1111         ret = add_qgroup_item(trans, quota_root, BTRFS_FS_TREE_OBJECTID);
1112         if (ret) {
1113                 btrfs_abort_transaction(trans, ret);
1114                 goto out_free_path;
1115         }
1116
1117         qgroup = add_qgroup_rb(fs_info, BTRFS_FS_TREE_OBJECTID);
1118         if (IS_ERR(qgroup)) {
1119                 ret = PTR_ERR(qgroup);
1120                 btrfs_abort_transaction(trans, ret);
1121                 goto out_free_path;
1122         }
1123         ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1124         if (ret < 0) {
1125                 btrfs_abort_transaction(trans, ret);
1126                 goto out_free_path;
1127         }
1128
1129         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1130         /*
1131          * Commit the transaction while not holding qgroup_ioctl_lock, to avoid
1132          * a deadlock with tasks concurrently doing other qgroup operations, such
1133          * adding/removing qgroups or adding/deleting qgroup relations for example,
1134          * because all qgroup operations first start or join a transaction and then
1135          * lock the qgroup_ioctl_lock mutex.
1136          * We are safe from a concurrent task trying to enable quotas, by calling
1137          * this function, since we are serialized by fs_info->subvol_sem.
1138          */
1139         ret = btrfs_commit_transaction(trans);
1140         trans = NULL;
1141         mutex_lock(&fs_info->qgroup_ioctl_lock);
1142         if (ret)
1143                 goto out_free_path;
1144
1145         /*
1146          * Set quota enabled flag after committing the transaction, to avoid
1147          * deadlocks on fs_info->qgroup_ioctl_lock with concurrent snapshot
1148          * creation.
1149          */
1150         spin_lock(&fs_info->qgroup_lock);
1151         fs_info->quota_root = quota_root;
1152         set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1153         spin_unlock(&fs_info->qgroup_lock);
1154
1155         ret = qgroup_rescan_init(fs_info, 0, 1);
1156         if (!ret) {
1157                 qgroup_rescan_zero_tracking(fs_info);
1158                 fs_info->qgroup_rescan_running = true;
1159                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
1160                                  &fs_info->qgroup_rescan_work);
1161         } else {
1162                 /*
1163                  * We have set both BTRFS_FS_QUOTA_ENABLED and
1164                  * BTRFS_QGROUP_STATUS_FLAG_ON, so we can only fail with
1165                  * -EINPROGRESS. That can happen because someone started the
1166                  * rescan worker by calling quota rescan ioctl before we
1167                  * attempted to initialize the rescan worker. Failure due to
1168                  * quotas disabled in the meanwhile is not possible, because
1169                  * we are holding a write lock on fs_info->subvol_sem, which
1170                  * is also acquired when disabling quotas.
1171                  * Ignore such error, and any other error would need to undo
1172                  * everything we did in the transaction we just committed.
1173                  */
1174                 ASSERT(ret == -EINPROGRESS);
1175                 ret = 0;
1176         }
1177
1178 out_free_path:
1179         btrfs_free_path(path);
1180 out_free_root:
1181         if (ret)
1182                 btrfs_put_root(quota_root);
1183 out:
1184         if (ret) {
1185                 ulist_free(fs_info->qgroup_ulist);
1186                 fs_info->qgroup_ulist = NULL;
1187                 btrfs_sysfs_del_qgroups(fs_info);
1188         }
1189         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1190         if (ret && trans)
1191                 btrfs_end_transaction(trans);
1192         else if (trans)
1193                 ret = btrfs_end_transaction(trans);
1194         ulist_free(ulist);
1195         return ret;
1196 }
1197
1198 int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
1199 {
1200         struct btrfs_root *quota_root;
1201         struct btrfs_trans_handle *trans = NULL;
1202         int ret = 0;
1203
1204         /*
1205          * We need to have subvol_sem write locked to prevent races with
1206          * snapshot creation.
1207          */
1208         lockdep_assert_held_write(&fs_info->subvol_sem);
1209
1210         /*
1211          * Lock the cleaner mutex to prevent races with concurrent relocation,
1212          * because relocation may be building backrefs for blocks of the quota
1213          * root while we are deleting the root. This is like dropping fs roots
1214          * of deleted snapshots/subvolumes, we need the same protection.
1215          *
1216          * This also prevents races between concurrent tasks trying to disable
1217          * quotas, because we will unlock and relock qgroup_ioctl_lock across
1218          * BTRFS_FS_QUOTA_ENABLED changes.
1219          */
1220         mutex_lock(&fs_info->cleaner_mutex);
1221
1222         mutex_lock(&fs_info->qgroup_ioctl_lock);
1223         if (!fs_info->quota_root)
1224                 goto out;
1225
1226         /*
1227          * Unlock the qgroup_ioctl_lock mutex before waiting for the rescan worker to
1228          * complete. Otherwise we can deadlock because btrfs_remove_qgroup() needs
1229          * to lock that mutex while holding a transaction handle and the rescan
1230          * worker needs to commit a transaction.
1231          */
1232         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1233
1234         /*
1235          * Request qgroup rescan worker to complete and wait for it. This wait
1236          * must be done before transaction start for quota disable since it may
1237          * deadlock with transaction by the qgroup rescan worker.
1238          */
1239         clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1240         btrfs_qgroup_wait_for_completion(fs_info, false);
1241
1242         /*
1243          * 1 For the root item
1244          *
1245          * We should also reserve enough items for the quota tree deletion in
1246          * btrfs_clean_quota_tree but this is not done.
1247          *
1248          * Also, we must always start a transaction without holding the mutex
1249          * qgroup_ioctl_lock, see btrfs_quota_enable().
1250          */
1251         trans = btrfs_start_transaction(fs_info->tree_root, 1);
1252
1253         mutex_lock(&fs_info->qgroup_ioctl_lock);
1254         if (IS_ERR(trans)) {
1255                 ret = PTR_ERR(trans);
1256                 trans = NULL;
1257                 set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1258                 goto out;
1259         }
1260
1261         if (!fs_info->quota_root)
1262                 goto out;
1263
1264         spin_lock(&fs_info->qgroup_lock);
1265         quota_root = fs_info->quota_root;
1266         fs_info->quota_root = NULL;
1267         fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
1268         spin_unlock(&fs_info->qgroup_lock);
1269
1270         btrfs_free_qgroup_config(fs_info);
1271
1272         ret = btrfs_clean_quota_tree(trans, quota_root);
1273         if (ret) {
1274                 btrfs_abort_transaction(trans, ret);
1275                 goto out;
1276         }
1277
1278         ret = btrfs_del_root(trans, &quota_root->root_key);
1279         if (ret) {
1280                 btrfs_abort_transaction(trans, ret);
1281                 goto out;
1282         }
1283
1284         spin_lock(&fs_info->trans_lock);
1285         list_del(&quota_root->dirty_list);
1286         spin_unlock(&fs_info->trans_lock);
1287
1288         btrfs_tree_lock(quota_root->node);
1289         btrfs_clean_tree_block(quota_root->node);
1290         btrfs_tree_unlock(quota_root->node);
1291         btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1);
1292
1293         btrfs_put_root(quota_root);
1294
1295 out:
1296         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1297         if (ret && trans)
1298                 btrfs_end_transaction(trans);
1299         else if (trans)
1300                 ret = btrfs_end_transaction(trans);
1301         mutex_unlock(&fs_info->cleaner_mutex);
1302
1303         return ret;
1304 }
1305
1306 static void qgroup_dirty(struct btrfs_fs_info *fs_info,
1307                          struct btrfs_qgroup *qgroup)
1308 {
1309         if (list_empty(&qgroup->dirty))
1310                 list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
1311 }
1312
1313 /*
1314  * The easy accounting, we're updating qgroup relationship whose child qgroup
1315  * only has exclusive extents.
1316  *
1317  * In this case, all exclusive extents will also be exclusive for parent, so
1318  * excl/rfer just get added/removed.
1319  *
1320  * So is qgroup reservation space, which should also be added/removed to
1321  * parent.
1322  * Or when child tries to release reservation space, parent will underflow its
1323  * reservation (for relationship adding case).
1324  *
1325  * Caller should hold fs_info->qgroup_lock.
1326  */
1327 static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
1328                                     struct ulist *tmp, u64 ref_root,
1329                                     struct btrfs_qgroup *src, int sign)
1330 {
1331         struct btrfs_qgroup *qgroup;
1332         struct btrfs_qgroup_list *glist;
1333         struct ulist_node *unode;
1334         struct ulist_iterator uiter;
1335         u64 num_bytes = src->excl;
1336         int ret = 0;
1337
1338         qgroup = find_qgroup_rb(fs_info, ref_root);
1339         if (!qgroup)
1340                 goto out;
1341
1342         qgroup->rfer += sign * num_bytes;
1343         qgroup->rfer_cmpr += sign * num_bytes;
1344
1345         WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1346         qgroup->excl += sign * num_bytes;
1347         qgroup->excl_cmpr += sign * num_bytes;
1348
1349         if (sign > 0)
1350                 qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1351         else
1352                 qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1353
1354         qgroup_dirty(fs_info, qgroup);
1355
1356         /* Get all of the parent groups that contain this qgroup */
1357         list_for_each_entry(glist, &qgroup->groups, next_group) {
1358                 ret = ulist_add(tmp, glist->group->qgroupid,
1359                                 qgroup_to_aux(glist->group), GFP_ATOMIC);
1360                 if (ret < 0)
1361                         goto out;
1362         }
1363
1364         /* Iterate all of the parents and adjust their reference counts */
1365         ULIST_ITER_INIT(&uiter);
1366         while ((unode = ulist_next(tmp, &uiter))) {
1367                 qgroup = unode_aux_to_qgroup(unode);
1368                 qgroup->rfer += sign * num_bytes;
1369                 qgroup->rfer_cmpr += sign * num_bytes;
1370                 WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1371                 qgroup->excl += sign * num_bytes;
1372                 if (sign > 0)
1373                         qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1374                 else
1375                         qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1376                 qgroup->excl_cmpr += sign * num_bytes;
1377                 qgroup_dirty(fs_info, qgroup);
1378
1379                 /* Add any parents of the parents */
1380                 list_for_each_entry(glist, &qgroup->groups, next_group) {
1381                         ret = ulist_add(tmp, glist->group->qgroupid,
1382                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
1383                         if (ret < 0)
1384                                 goto out;
1385                 }
1386         }
1387         ret = 0;
1388 out:
1389         return ret;
1390 }
1391
1392
1393 /*
1394  * Quick path for updating qgroup with only excl refs.
1395  *
1396  * In that case, just update all parent will be enough.
1397  * Or we needs to do a full rescan.
1398  * Caller should also hold fs_info->qgroup_lock.
1399  *
1400  * Return 0 for quick update, return >0 for need to full rescan
1401  * and mark INCONSISTENT flag.
1402  * Return < 0 for other error.
1403  */
1404 static int quick_update_accounting(struct btrfs_fs_info *fs_info,
1405                                    struct ulist *tmp, u64 src, u64 dst,
1406                                    int sign)
1407 {
1408         struct btrfs_qgroup *qgroup;
1409         int ret = 1;
1410         int err = 0;
1411
1412         qgroup = find_qgroup_rb(fs_info, src);
1413         if (!qgroup)
1414                 goto out;
1415         if (qgroup->excl == qgroup->rfer) {
1416                 ret = 0;
1417                 err = __qgroup_excl_accounting(fs_info, tmp, dst,
1418                                                qgroup, sign);
1419                 if (err < 0) {
1420                         ret = err;
1421                         goto out;
1422                 }
1423         }
1424 out:
1425         if (ret)
1426                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1427         return ret;
1428 }
1429
1430 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1431                               u64 dst)
1432 {
1433         struct btrfs_fs_info *fs_info = trans->fs_info;
1434         struct btrfs_qgroup *parent;
1435         struct btrfs_qgroup *member;
1436         struct btrfs_qgroup_list *list;
1437         struct ulist *tmp;
1438         unsigned int nofs_flag;
1439         int ret = 0;
1440
1441         /* Check the level of src and dst first */
1442         if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
1443                 return -EINVAL;
1444
1445         /* We hold a transaction handle open, must do a NOFS allocation. */
1446         nofs_flag = memalloc_nofs_save();
1447         tmp = ulist_alloc(GFP_KERNEL);
1448         memalloc_nofs_restore(nofs_flag);
1449         if (!tmp)
1450                 return -ENOMEM;
1451
1452         mutex_lock(&fs_info->qgroup_ioctl_lock);
1453         if (!fs_info->quota_root) {
1454                 ret = -ENOTCONN;
1455                 goto out;
1456         }
1457         member = find_qgroup_rb(fs_info, src);
1458         parent = find_qgroup_rb(fs_info, dst);
1459         if (!member || !parent) {
1460                 ret = -EINVAL;
1461                 goto out;
1462         }
1463
1464         /* check if such qgroup relation exist firstly */
1465         list_for_each_entry(list, &member->groups, next_group) {
1466                 if (list->group == parent) {
1467                         ret = -EEXIST;
1468                         goto out;
1469                 }
1470         }
1471
1472         ret = add_qgroup_relation_item(trans, src, dst);
1473         if (ret)
1474                 goto out;
1475
1476         ret = add_qgroup_relation_item(trans, dst, src);
1477         if (ret) {
1478                 del_qgroup_relation_item(trans, src, dst);
1479                 goto out;
1480         }
1481
1482         spin_lock(&fs_info->qgroup_lock);
1483         ret = add_relation_rb(fs_info, src, dst);
1484         if (ret < 0) {
1485                 spin_unlock(&fs_info->qgroup_lock);
1486                 goto out;
1487         }
1488         ret = quick_update_accounting(fs_info, tmp, src, dst, 1);
1489         spin_unlock(&fs_info->qgroup_lock);
1490 out:
1491         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1492         ulist_free(tmp);
1493         return ret;
1494 }
1495
1496 static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1497                                  u64 dst)
1498 {
1499         struct btrfs_fs_info *fs_info = trans->fs_info;
1500         struct btrfs_qgroup *parent;
1501         struct btrfs_qgroup *member;
1502         struct btrfs_qgroup_list *list;
1503         struct ulist *tmp;
1504         bool found = false;
1505         unsigned int nofs_flag;
1506         int ret = 0;
1507         int ret2;
1508
1509         /* We hold a transaction handle open, must do a NOFS allocation. */
1510         nofs_flag = memalloc_nofs_save();
1511         tmp = ulist_alloc(GFP_KERNEL);
1512         memalloc_nofs_restore(nofs_flag);
1513         if (!tmp)
1514                 return -ENOMEM;
1515
1516         if (!fs_info->quota_root) {
1517                 ret = -ENOTCONN;
1518                 goto out;
1519         }
1520
1521         member = find_qgroup_rb(fs_info, src);
1522         parent = find_qgroup_rb(fs_info, dst);
1523         /*
1524          * The parent/member pair doesn't exist, then try to delete the dead
1525          * relation items only.
1526          */
1527         if (!member || !parent)
1528                 goto delete_item;
1529
1530         /* check if such qgroup relation exist firstly */
1531         list_for_each_entry(list, &member->groups, next_group) {
1532                 if (list->group == parent) {
1533                         found = true;
1534                         break;
1535                 }
1536         }
1537
1538 delete_item:
1539         ret = del_qgroup_relation_item(trans, src, dst);
1540         if (ret < 0 && ret != -ENOENT)
1541                 goto out;
1542         ret2 = del_qgroup_relation_item(trans, dst, src);
1543         if (ret2 < 0 && ret2 != -ENOENT)
1544                 goto out;
1545
1546         /* At least one deletion succeeded, return 0 */
1547         if (!ret || !ret2)
1548                 ret = 0;
1549
1550         if (found) {
1551                 spin_lock(&fs_info->qgroup_lock);
1552                 del_relation_rb(fs_info, src, dst);
1553                 ret = quick_update_accounting(fs_info, tmp, src, dst, -1);
1554                 spin_unlock(&fs_info->qgroup_lock);
1555         }
1556 out:
1557         ulist_free(tmp);
1558         return ret;
1559 }
1560
1561 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1562                               u64 dst)
1563 {
1564         struct btrfs_fs_info *fs_info = trans->fs_info;
1565         int ret = 0;
1566
1567         mutex_lock(&fs_info->qgroup_ioctl_lock);
1568         ret = __del_qgroup_relation(trans, src, dst);
1569         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1570
1571         return ret;
1572 }
1573
1574 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1575 {
1576         struct btrfs_fs_info *fs_info = trans->fs_info;
1577         struct btrfs_root *quota_root;
1578         struct btrfs_qgroup *qgroup;
1579         int ret = 0;
1580
1581         mutex_lock(&fs_info->qgroup_ioctl_lock);
1582         if (!fs_info->quota_root) {
1583                 ret = -ENOTCONN;
1584                 goto out;
1585         }
1586         quota_root = fs_info->quota_root;
1587         qgroup = find_qgroup_rb(fs_info, qgroupid);
1588         if (qgroup) {
1589                 ret = -EEXIST;
1590                 goto out;
1591         }
1592
1593         ret = add_qgroup_item(trans, quota_root, qgroupid);
1594         if (ret)
1595                 goto out;
1596
1597         spin_lock(&fs_info->qgroup_lock);
1598         qgroup = add_qgroup_rb(fs_info, qgroupid);
1599         spin_unlock(&fs_info->qgroup_lock);
1600
1601         if (IS_ERR(qgroup)) {
1602                 ret = PTR_ERR(qgroup);
1603                 goto out;
1604         }
1605         ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1606 out:
1607         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1608         return ret;
1609 }
1610
1611 static bool qgroup_has_usage(struct btrfs_qgroup *qgroup)
1612 {
1613         return (qgroup->rfer > 0 || qgroup->rfer_cmpr > 0 ||
1614                 qgroup->excl > 0 || qgroup->excl_cmpr > 0 ||
1615                 qgroup->rsv.values[BTRFS_QGROUP_RSV_DATA] > 0 ||
1616                 qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC] > 0 ||
1617                 qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS] > 0);
1618 }
1619
1620 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1621 {
1622         struct btrfs_fs_info *fs_info = trans->fs_info;
1623         struct btrfs_qgroup *qgroup;
1624         struct btrfs_qgroup_list *list;
1625         int ret = 0;
1626
1627         mutex_lock(&fs_info->qgroup_ioctl_lock);
1628         if (!fs_info->quota_root) {
1629                 ret = -ENOTCONN;
1630                 goto out;
1631         }
1632
1633         qgroup = find_qgroup_rb(fs_info, qgroupid);
1634         if (!qgroup) {
1635                 ret = -ENOENT;
1636                 goto out;
1637         }
1638
1639         if (is_fstree(qgroupid) && qgroup_has_usage(qgroup)) {
1640                 ret = -EBUSY;
1641                 goto out;
1642         }
1643
1644         /* Check if there are no children of this qgroup */
1645         if (!list_empty(&qgroup->members)) {
1646                 ret = -EBUSY;
1647                 goto out;
1648         }
1649
1650         ret = del_qgroup_item(trans, qgroupid);
1651         if (ret && ret != -ENOENT)
1652                 goto out;
1653
1654         while (!list_empty(&qgroup->groups)) {
1655                 list = list_first_entry(&qgroup->groups,
1656                                         struct btrfs_qgroup_list, next_group);
1657                 ret = __del_qgroup_relation(trans, qgroupid,
1658                                             list->group->qgroupid);
1659                 if (ret)
1660                         goto out;
1661         }
1662
1663         spin_lock(&fs_info->qgroup_lock);
1664         del_qgroup_rb(fs_info, qgroupid);
1665         spin_unlock(&fs_info->qgroup_lock);
1666
1667         /*
1668          * Remove the qgroup from sysfs now without holding the qgroup_lock
1669          * spinlock, since the sysfs_remove_group() function needs to take
1670          * the mutex kernfs_mutex through kernfs_remove_by_name_ns().
1671          */
1672         btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
1673         kfree(qgroup);
1674 out:
1675         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1676         return ret;
1677 }
1678
1679 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
1680                        struct btrfs_qgroup_limit *limit)
1681 {
1682         struct btrfs_fs_info *fs_info = trans->fs_info;
1683         struct btrfs_qgroup *qgroup;
1684         int ret = 0;
1685         /* Sometimes we would want to clear the limit on this qgroup.
1686          * To meet this requirement, we treat the -1 as a special value
1687          * which tell kernel to clear the limit on this qgroup.
1688          */
1689         const u64 CLEAR_VALUE = -1;
1690
1691         mutex_lock(&fs_info->qgroup_ioctl_lock);
1692         if (!fs_info->quota_root) {
1693                 ret = -ENOTCONN;
1694                 goto out;
1695         }
1696
1697         qgroup = find_qgroup_rb(fs_info, qgroupid);
1698         if (!qgroup) {
1699                 ret = -ENOENT;
1700                 goto out;
1701         }
1702
1703         spin_lock(&fs_info->qgroup_lock);
1704         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_RFER) {
1705                 if (limit->max_rfer == CLEAR_VALUE) {
1706                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1707                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1708                         qgroup->max_rfer = 0;
1709                 } else {
1710                         qgroup->max_rfer = limit->max_rfer;
1711                 }
1712         }
1713         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
1714                 if (limit->max_excl == CLEAR_VALUE) {
1715                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1716                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1717                         qgroup->max_excl = 0;
1718                 } else {
1719                         qgroup->max_excl = limit->max_excl;
1720                 }
1721         }
1722         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_RFER) {
1723                 if (limit->rsv_rfer == CLEAR_VALUE) {
1724                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1725                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1726                         qgroup->rsv_rfer = 0;
1727                 } else {
1728                         qgroup->rsv_rfer = limit->rsv_rfer;
1729                 }
1730         }
1731         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_EXCL) {
1732                 if (limit->rsv_excl == CLEAR_VALUE) {
1733                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1734                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1735                         qgroup->rsv_excl = 0;
1736                 } else {
1737                         qgroup->rsv_excl = limit->rsv_excl;
1738                 }
1739         }
1740         qgroup->lim_flags |= limit->flags;
1741
1742         spin_unlock(&fs_info->qgroup_lock);
1743
1744         ret = update_qgroup_limit_item(trans, qgroup);
1745         if (ret) {
1746                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1747                 btrfs_info(fs_info, "unable to update quota limit for %llu",
1748                        qgroupid);
1749         }
1750
1751 out:
1752         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1753         return ret;
1754 }
1755
1756 int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
1757                                 struct btrfs_delayed_ref_root *delayed_refs,
1758                                 struct btrfs_qgroup_extent_record *record)
1759 {
1760         struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
1761         struct rb_node *parent_node = NULL;
1762         struct btrfs_qgroup_extent_record *entry;
1763         u64 bytenr = record->bytenr;
1764
1765         lockdep_assert_held(&delayed_refs->lock);
1766         trace_btrfs_qgroup_trace_extent(fs_info, record);
1767
1768         while (*p) {
1769                 parent_node = *p;
1770                 entry = rb_entry(parent_node, struct btrfs_qgroup_extent_record,
1771                                  node);
1772                 if (bytenr < entry->bytenr) {
1773                         p = &(*p)->rb_left;
1774                 } else if (bytenr > entry->bytenr) {
1775                         p = &(*p)->rb_right;
1776                 } else {
1777                         if (record->data_rsv && !entry->data_rsv) {
1778                                 entry->data_rsv = record->data_rsv;
1779                                 entry->data_rsv_refroot =
1780                                         record->data_rsv_refroot;
1781                         }
1782                         return 1;
1783                 }
1784         }
1785
1786         rb_link_node(&record->node, parent_node, p);
1787         rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
1788         return 0;
1789 }
1790
1791 int btrfs_qgroup_trace_extent_post(struct btrfs_fs_info *fs_info,
1792                                    struct btrfs_qgroup_extent_record *qrecord)
1793 {
1794         struct ulist *old_root;
1795         u64 bytenr = qrecord->bytenr;
1796         int ret;
1797
1798         ret = btrfs_find_all_roots(NULL, fs_info, bytenr, 0, &old_root, false);
1799         if (ret < 0) {
1800                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1801                 btrfs_warn(fs_info,
1802 "error accounting new delayed refs extent (err code: %d), quota inconsistent",
1803                         ret);
1804                 return 0;
1805         }
1806
1807         /*
1808          * Here we don't need to get the lock of
1809          * trans->transaction->delayed_refs, since inserted qrecord won't
1810          * be deleted, only qrecord->node may be modified (new qrecord insert)
1811          *
1812          * So modifying qrecord->old_roots is safe here
1813          */
1814         qrecord->old_roots = old_root;
1815         return 0;
1816 }
1817
1818 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
1819                               u64 num_bytes, gfp_t gfp_flag)
1820 {
1821         struct btrfs_fs_info *fs_info = trans->fs_info;
1822         struct btrfs_qgroup_extent_record *record;
1823         struct btrfs_delayed_ref_root *delayed_refs;
1824         int ret;
1825
1826         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)
1827             || bytenr == 0 || num_bytes == 0)
1828                 return 0;
1829         record = kzalloc(sizeof(*record), gfp_flag);
1830         if (!record)
1831                 return -ENOMEM;
1832
1833         delayed_refs = &trans->transaction->delayed_refs;
1834         record->bytenr = bytenr;
1835         record->num_bytes = num_bytes;
1836         record->old_roots = NULL;
1837
1838         spin_lock(&delayed_refs->lock);
1839         ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record);
1840         spin_unlock(&delayed_refs->lock);
1841         if (ret > 0) {
1842                 kfree(record);
1843                 return 0;
1844         }
1845         return btrfs_qgroup_trace_extent_post(fs_info, record);
1846 }
1847
1848 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
1849                                   struct extent_buffer *eb)
1850 {
1851         struct btrfs_fs_info *fs_info = trans->fs_info;
1852         int nr = btrfs_header_nritems(eb);
1853         int i, extent_type, ret;
1854         struct btrfs_key key;
1855         struct btrfs_file_extent_item *fi;
1856         u64 bytenr, num_bytes;
1857
1858         /* We can be called directly from walk_up_proc() */
1859         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1860                 return 0;
1861
1862         for (i = 0; i < nr; i++) {
1863                 btrfs_item_key_to_cpu(eb, &key, i);
1864
1865                 if (key.type != BTRFS_EXTENT_DATA_KEY)
1866                         continue;
1867
1868                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
1869                 /* filter out non qgroup-accountable extents  */
1870                 extent_type = btrfs_file_extent_type(eb, fi);
1871
1872                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
1873                         continue;
1874
1875                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
1876                 if (!bytenr)
1877                         continue;
1878
1879                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
1880
1881                 ret = btrfs_qgroup_trace_extent(trans, bytenr, num_bytes,
1882                                                 GFP_NOFS);
1883                 if (ret)
1884                         return ret;
1885         }
1886         cond_resched();
1887         return 0;
1888 }
1889
1890 /*
1891  * Walk up the tree from the bottom, freeing leaves and any interior
1892  * nodes which have had all slots visited. If a node (leaf or
1893  * interior) is freed, the node above it will have it's slot
1894  * incremented. The root node will never be freed.
1895  *
1896  * At the end of this function, we should have a path which has all
1897  * slots incremented to the next position for a search. If we need to
1898  * read a new node it will be NULL and the node above it will have the
1899  * correct slot selected for a later read.
1900  *
1901  * If we increment the root nodes slot counter past the number of
1902  * elements, 1 is returned to signal completion of the search.
1903  */
1904 static int adjust_slots_upwards(struct btrfs_path *path, int root_level)
1905 {
1906         int level = 0;
1907         int nr, slot;
1908         struct extent_buffer *eb;
1909
1910         if (root_level == 0)
1911                 return 1;
1912
1913         while (level <= root_level) {
1914                 eb = path->nodes[level];
1915                 nr = btrfs_header_nritems(eb);
1916                 path->slots[level]++;
1917                 slot = path->slots[level];
1918                 if (slot >= nr || level == 0) {
1919                         /*
1920                          * Don't free the root -  we will detect this
1921                          * condition after our loop and return a
1922                          * positive value for caller to stop walking the tree.
1923                          */
1924                         if (level != root_level) {
1925                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
1926                                 path->locks[level] = 0;
1927
1928                                 free_extent_buffer(eb);
1929                                 path->nodes[level] = NULL;
1930                                 path->slots[level] = 0;
1931                         }
1932                 } else {
1933                         /*
1934                          * We have a valid slot to walk back down
1935                          * from. Stop here so caller can process these
1936                          * new nodes.
1937                          */
1938                         break;
1939                 }
1940
1941                 level++;
1942         }
1943
1944         eb = path->nodes[root_level];
1945         if (path->slots[root_level] >= btrfs_header_nritems(eb))
1946                 return 1;
1947
1948         return 0;
1949 }
1950
1951 /*
1952  * Helper function to trace a subtree tree block swap.
1953  *
1954  * The swap will happen in highest tree block, but there may be a lot of
1955  * tree blocks involved.
1956  *
1957  * For example:
1958  *  OO = Old tree blocks
1959  *  NN = New tree blocks allocated during balance
1960  *
1961  *           File tree (257)                  Reloc tree for 257
1962  * L2              OO                                NN
1963  *               /    \                            /    \
1964  * L1          OO      OO (a)                    OO      NN (a)
1965  *            / \     / \                       / \     / \
1966  * L0       OO   OO OO   OO                   OO   OO NN   NN
1967  *                  (b)  (c)                          (b)  (c)
1968  *
1969  * When calling qgroup_trace_extent_swap(), we will pass:
1970  * @src_eb = OO(a)
1971  * @dst_path = [ nodes[1] = NN(a), nodes[0] = NN(c) ]
1972  * @dst_level = 0
1973  * @root_level = 1
1974  *
1975  * In that case, qgroup_trace_extent_swap() will search from OO(a) to
1976  * reach OO(c), then mark both OO(c) and NN(c) as qgroup dirty.
1977  *
1978  * The main work of qgroup_trace_extent_swap() can be split into 3 parts:
1979  *
1980  * 1) Tree search from @src_eb
1981  *    It should acts as a simplified btrfs_search_slot().
1982  *    The key for search can be extracted from @dst_path->nodes[dst_level]
1983  *    (first key).
1984  *
1985  * 2) Mark the final tree blocks in @src_path and @dst_path qgroup dirty
1986  *    NOTE: In above case, OO(a) and NN(a) won't be marked qgroup dirty.
1987  *    They should be marked during previous (@dst_level = 1) iteration.
1988  *
1989  * 3) Mark file extents in leaves dirty
1990  *    We don't have good way to pick out new file extents only.
1991  *    So we still follow the old method by scanning all file extents in
1992  *    the leave.
1993  *
1994  * This function can free us from keeping two paths, thus later we only need
1995  * to care about how to iterate all new tree blocks in reloc tree.
1996  */
1997 static int qgroup_trace_extent_swap(struct btrfs_trans_handle* trans,
1998                                     struct extent_buffer *src_eb,
1999                                     struct btrfs_path *dst_path,
2000                                     int dst_level, int root_level,
2001                                     bool trace_leaf)
2002 {
2003         struct btrfs_key key;
2004         struct btrfs_path *src_path;
2005         struct btrfs_fs_info *fs_info = trans->fs_info;
2006         u32 nodesize = fs_info->nodesize;
2007         int cur_level = root_level;
2008         int ret;
2009
2010         BUG_ON(dst_level > root_level);
2011         /* Level mismatch */
2012         if (btrfs_header_level(src_eb) != root_level)
2013                 return -EINVAL;
2014
2015         src_path = btrfs_alloc_path();
2016         if (!src_path) {
2017                 ret = -ENOMEM;
2018                 goto out;
2019         }
2020
2021         if (dst_level)
2022                 btrfs_node_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
2023         else
2024                 btrfs_item_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
2025
2026         /* For src_path */
2027         atomic_inc(&src_eb->refs);
2028         src_path->nodes[root_level] = src_eb;
2029         src_path->slots[root_level] = dst_path->slots[root_level];
2030         src_path->locks[root_level] = 0;
2031
2032         /* A simplified version of btrfs_search_slot() */
2033         while (cur_level >= dst_level) {
2034                 struct btrfs_key src_key;
2035                 struct btrfs_key dst_key;
2036
2037                 if (src_path->nodes[cur_level] == NULL) {
2038                         struct btrfs_key first_key;
2039                         struct extent_buffer *eb;
2040                         int parent_slot;
2041                         u64 child_gen;
2042                         u64 child_bytenr;
2043
2044                         eb = src_path->nodes[cur_level + 1];
2045                         parent_slot = src_path->slots[cur_level + 1];
2046                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
2047                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
2048                         btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
2049
2050                         eb = read_tree_block(fs_info, child_bytenr, child_gen,
2051                                              cur_level, &first_key);
2052                         if (IS_ERR(eb)) {
2053                                 ret = PTR_ERR(eb);
2054                                 goto out;
2055                         } else if (!extent_buffer_uptodate(eb)) {
2056                                 free_extent_buffer(eb);
2057                                 ret = -EIO;
2058                                 goto out;
2059                         }
2060
2061                         src_path->nodes[cur_level] = eb;
2062
2063                         btrfs_tree_read_lock(eb);
2064                         btrfs_set_lock_blocking_read(eb);
2065                         src_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
2066                 }
2067
2068                 src_path->slots[cur_level] = dst_path->slots[cur_level];
2069                 if (cur_level) {
2070                         btrfs_node_key_to_cpu(dst_path->nodes[cur_level],
2071                                         &dst_key, dst_path->slots[cur_level]);
2072                         btrfs_node_key_to_cpu(src_path->nodes[cur_level],
2073                                         &src_key, src_path->slots[cur_level]);
2074                 } else {
2075                         btrfs_item_key_to_cpu(dst_path->nodes[cur_level],
2076                                         &dst_key, dst_path->slots[cur_level]);
2077                         btrfs_item_key_to_cpu(src_path->nodes[cur_level],
2078                                         &src_key, src_path->slots[cur_level]);
2079                 }
2080                 /* Content mismatch, something went wrong */
2081                 if (btrfs_comp_cpu_keys(&dst_key, &src_key)) {
2082                         ret = -ENOENT;
2083                         goto out;
2084                 }
2085                 cur_level--;
2086         }
2087
2088         /*
2089          * Now both @dst_path and @src_path have been populated, record the tree
2090          * blocks for qgroup accounting.
2091          */
2092         ret = btrfs_qgroup_trace_extent(trans, src_path->nodes[dst_level]->start,
2093                         nodesize, GFP_NOFS);
2094         if (ret < 0)
2095                 goto out;
2096         ret = btrfs_qgroup_trace_extent(trans,
2097                         dst_path->nodes[dst_level]->start,
2098                         nodesize, GFP_NOFS);
2099         if (ret < 0)
2100                 goto out;
2101
2102         /* Record leaf file extents */
2103         if (dst_level == 0 && trace_leaf) {
2104                 ret = btrfs_qgroup_trace_leaf_items(trans, src_path->nodes[0]);
2105                 if (ret < 0)
2106                         goto out;
2107                 ret = btrfs_qgroup_trace_leaf_items(trans, dst_path->nodes[0]);
2108         }
2109 out:
2110         btrfs_free_path(src_path);
2111         return ret;
2112 }
2113
2114 /*
2115  * Helper function to do recursive generation-aware depth-first search, to
2116  * locate all new tree blocks in a subtree of reloc tree.
2117  *
2118  * E.g. (OO = Old tree blocks, NN = New tree blocks, whose gen == last_snapshot)
2119  *         reloc tree
2120  * L2         NN (a)
2121  *          /    \
2122  * L1    OO        NN (b)
2123  *      /  \      /  \
2124  * L0  OO  OO    OO  NN
2125  *               (c) (d)
2126  * If we pass:
2127  * @dst_path = [ nodes[1] = NN(b), nodes[0] = NULL ],
2128  * @cur_level = 1
2129  * @root_level = 1
2130  *
2131  * We will iterate through tree blocks NN(b), NN(d) and info qgroup to trace
2132  * above tree blocks along with their counter parts in file tree.
2133  * While during search, old tree blocks OO(c) will be skipped as tree block swap
2134  * won't affect OO(c).
2135  */
2136 static int qgroup_trace_new_subtree_blocks(struct btrfs_trans_handle* trans,
2137                                            struct extent_buffer *src_eb,
2138                                            struct btrfs_path *dst_path,
2139                                            int cur_level, int root_level,
2140                                            u64 last_snapshot, bool trace_leaf)
2141 {
2142         struct btrfs_fs_info *fs_info = trans->fs_info;
2143         struct extent_buffer *eb;
2144         bool need_cleanup = false;
2145         int ret = 0;
2146         int i;
2147
2148         /* Level sanity check */
2149         if (cur_level < 0 || cur_level >= BTRFS_MAX_LEVEL - 1 ||
2150             root_level < 0 || root_level >= BTRFS_MAX_LEVEL - 1 ||
2151             root_level < cur_level) {
2152                 btrfs_err_rl(fs_info,
2153                         "%s: bad levels, cur_level=%d root_level=%d",
2154                         __func__, cur_level, root_level);
2155                 return -EUCLEAN;
2156         }
2157
2158         /* Read the tree block if needed */
2159         if (dst_path->nodes[cur_level] == NULL) {
2160                 struct btrfs_key first_key;
2161                 int parent_slot;
2162                 u64 child_gen;
2163                 u64 child_bytenr;
2164
2165                 /*
2166                  * dst_path->nodes[root_level] must be initialized before
2167                  * calling this function.
2168                  */
2169                 if (cur_level == root_level) {
2170                         btrfs_err_rl(fs_info,
2171         "%s: dst_path->nodes[%d] not initialized, root_level=%d cur_level=%d",
2172                                 __func__, root_level, root_level, cur_level);
2173                         return -EUCLEAN;
2174                 }
2175
2176                 /*
2177                  * We need to get child blockptr/gen from parent before we can
2178                  * read it.
2179                   */
2180                 eb = dst_path->nodes[cur_level + 1];
2181                 parent_slot = dst_path->slots[cur_level + 1];
2182                 child_bytenr = btrfs_node_blockptr(eb, parent_slot);
2183                 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
2184                 btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
2185
2186                 /* This node is old, no need to trace */
2187                 if (child_gen < last_snapshot)
2188                         goto out;
2189
2190                 eb = read_tree_block(fs_info, child_bytenr, child_gen,
2191                                      cur_level, &first_key);
2192                 if (IS_ERR(eb)) {
2193                         ret = PTR_ERR(eb);
2194                         goto out;
2195                 } else if (!extent_buffer_uptodate(eb)) {
2196                         free_extent_buffer(eb);
2197                         ret = -EIO;
2198                         goto out;
2199                 }
2200
2201                 dst_path->nodes[cur_level] = eb;
2202                 dst_path->slots[cur_level] = 0;
2203
2204                 btrfs_tree_read_lock(eb);
2205                 btrfs_set_lock_blocking_read(eb);
2206                 dst_path->locks[cur_level] = BTRFS_READ_LOCK_BLOCKING;
2207                 need_cleanup = true;
2208         }
2209
2210         /* Now record this tree block and its counter part for qgroups */
2211         ret = qgroup_trace_extent_swap(trans, src_eb, dst_path, cur_level,
2212                                        root_level, trace_leaf);
2213         if (ret < 0)
2214                 goto cleanup;
2215
2216         eb = dst_path->nodes[cur_level];
2217
2218         if (cur_level > 0) {
2219                 /* Iterate all child tree blocks */
2220                 for (i = 0; i < btrfs_header_nritems(eb); i++) {
2221                         /* Skip old tree blocks as they won't be swapped */
2222                         if (btrfs_node_ptr_generation(eb, i) < last_snapshot)
2223                                 continue;
2224                         dst_path->slots[cur_level] = i;
2225
2226                         /* Recursive call (at most 7 times) */
2227                         ret = qgroup_trace_new_subtree_blocks(trans, src_eb,
2228                                         dst_path, cur_level - 1, root_level,
2229                                         last_snapshot, trace_leaf);
2230                         if (ret < 0)
2231                                 goto cleanup;
2232                 }
2233         }
2234
2235 cleanup:
2236         if (need_cleanup) {
2237                 /* Clean up */
2238                 btrfs_tree_unlock_rw(dst_path->nodes[cur_level],
2239                                      dst_path->locks[cur_level]);
2240                 free_extent_buffer(dst_path->nodes[cur_level]);
2241                 dst_path->nodes[cur_level] = NULL;
2242                 dst_path->slots[cur_level] = 0;
2243                 dst_path->locks[cur_level] = 0;
2244         }
2245 out:
2246         return ret;
2247 }
2248
2249 static int qgroup_trace_subtree_swap(struct btrfs_trans_handle *trans,
2250                                 struct extent_buffer *src_eb,
2251                                 struct extent_buffer *dst_eb,
2252                                 u64 last_snapshot, bool trace_leaf)
2253 {
2254         struct btrfs_fs_info *fs_info = trans->fs_info;
2255         struct btrfs_path *dst_path = NULL;
2256         int level;
2257         int ret;
2258
2259         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2260                 return 0;
2261
2262         /* Wrong parameter order */
2263         if (btrfs_header_generation(src_eb) > btrfs_header_generation(dst_eb)) {
2264                 btrfs_err_rl(fs_info,
2265                 "%s: bad parameter order, src_gen=%llu dst_gen=%llu", __func__,
2266                              btrfs_header_generation(src_eb),
2267                              btrfs_header_generation(dst_eb));
2268                 return -EUCLEAN;
2269         }
2270
2271         if (!extent_buffer_uptodate(src_eb) || !extent_buffer_uptodate(dst_eb)) {
2272                 ret = -EIO;
2273                 goto out;
2274         }
2275
2276         level = btrfs_header_level(dst_eb);
2277         dst_path = btrfs_alloc_path();
2278         if (!dst_path) {
2279                 ret = -ENOMEM;
2280                 goto out;
2281         }
2282         /* For dst_path */
2283         atomic_inc(&dst_eb->refs);
2284         dst_path->nodes[level] = dst_eb;
2285         dst_path->slots[level] = 0;
2286         dst_path->locks[level] = 0;
2287
2288         /* Do the generation aware breadth-first search */
2289         ret = qgroup_trace_new_subtree_blocks(trans, src_eb, dst_path, level,
2290                                               level, last_snapshot, trace_leaf);
2291         if (ret < 0)
2292                 goto out;
2293         ret = 0;
2294
2295 out:
2296         btrfs_free_path(dst_path);
2297         if (ret < 0)
2298                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2299         return ret;
2300 }
2301
2302 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
2303                                struct extent_buffer *root_eb,
2304                                u64 root_gen, int root_level)
2305 {
2306         struct btrfs_fs_info *fs_info = trans->fs_info;
2307         int ret = 0;
2308         int level;
2309         struct extent_buffer *eb = root_eb;
2310         struct btrfs_path *path = NULL;
2311
2312         BUG_ON(root_level < 0 || root_level >= BTRFS_MAX_LEVEL);
2313         BUG_ON(root_eb == NULL);
2314
2315         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2316                 return 0;
2317
2318         if (!extent_buffer_uptodate(root_eb)) {
2319                 ret = btrfs_read_buffer(root_eb, root_gen, root_level, NULL);
2320                 if (ret)
2321                         goto out;
2322         }
2323
2324         if (root_level == 0) {
2325                 ret = btrfs_qgroup_trace_leaf_items(trans, root_eb);
2326                 goto out;
2327         }
2328
2329         path = btrfs_alloc_path();
2330         if (!path)
2331                 return -ENOMEM;
2332
2333         /*
2334          * Walk down the tree.  Missing extent blocks are filled in as
2335          * we go. Metadata is accounted every time we read a new
2336          * extent block.
2337          *
2338          * When we reach a leaf, we account for file extent items in it,
2339          * walk back up the tree (adjusting slot pointers as we go)
2340          * and restart the search process.
2341          */
2342         atomic_inc(&root_eb->refs);     /* For path */
2343         path->nodes[root_level] = root_eb;
2344         path->slots[root_level] = 0;
2345         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
2346 walk_down:
2347         level = root_level;
2348         while (level >= 0) {
2349                 if (path->nodes[level] == NULL) {
2350                         struct btrfs_key first_key;
2351                         int parent_slot;
2352                         u64 child_gen;
2353                         u64 child_bytenr;
2354
2355                         /*
2356                          * We need to get child blockptr/gen from parent before
2357                          * we can read it.
2358                           */
2359                         eb = path->nodes[level + 1];
2360                         parent_slot = path->slots[level + 1];
2361                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
2362                         child_gen = btrfs_node_ptr_generation(eb, parent_slot);
2363                         btrfs_node_key_to_cpu(eb, &first_key, parent_slot);
2364
2365                         eb = read_tree_block(fs_info, child_bytenr, child_gen,
2366                                              level, &first_key);
2367                         if (IS_ERR(eb)) {
2368                                 ret = PTR_ERR(eb);
2369                                 goto out;
2370                         } else if (!extent_buffer_uptodate(eb)) {
2371                                 free_extent_buffer(eb);
2372                                 ret = -EIO;
2373                                 goto out;
2374                         }
2375
2376                         path->nodes[level] = eb;
2377                         path->slots[level] = 0;
2378
2379                         btrfs_tree_read_lock(eb);
2380                         btrfs_set_lock_blocking_read(eb);
2381                         path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
2382
2383                         ret = btrfs_qgroup_trace_extent(trans, child_bytenr,
2384                                                         fs_info->nodesize,
2385                                                         GFP_NOFS);
2386                         if (ret)
2387                                 goto out;
2388                 }
2389
2390                 if (level == 0) {
2391                         ret = btrfs_qgroup_trace_leaf_items(trans,
2392                                                             path->nodes[level]);
2393                         if (ret)
2394                                 goto out;
2395
2396                         /* Nonzero return here means we completed our search */
2397                         ret = adjust_slots_upwards(path, root_level);
2398                         if (ret)
2399                                 break;
2400
2401                         /* Restart search with new slots */
2402                         goto walk_down;
2403                 }
2404
2405                 level--;
2406         }
2407
2408         ret = 0;
2409 out:
2410         btrfs_free_path(path);
2411
2412         return ret;
2413 }
2414
2415 #define UPDATE_NEW      0
2416 #define UPDATE_OLD      1
2417 /*
2418  * Walk all of the roots that points to the bytenr and adjust their refcnts.
2419  */
2420 static int qgroup_update_refcnt(struct btrfs_fs_info *fs_info,
2421                                 struct ulist *roots, struct ulist *tmp,
2422                                 struct ulist *qgroups, u64 seq, int update_old)
2423 {
2424         struct ulist_node *unode;
2425         struct ulist_iterator uiter;
2426         struct ulist_node *tmp_unode;
2427         struct ulist_iterator tmp_uiter;
2428         struct btrfs_qgroup *qg;
2429         int ret = 0;
2430
2431         if (!roots)
2432                 return 0;
2433         ULIST_ITER_INIT(&uiter);
2434         while ((unode = ulist_next(roots, &uiter))) {
2435                 qg = find_qgroup_rb(fs_info, unode->val);
2436                 if (!qg)
2437                         continue;
2438
2439                 ulist_reinit(tmp);
2440                 ret = ulist_add(qgroups, qg->qgroupid, qgroup_to_aux(qg),
2441                                 GFP_ATOMIC);
2442                 if (ret < 0)
2443                         return ret;
2444                 ret = ulist_add(tmp, qg->qgroupid, qgroup_to_aux(qg), GFP_ATOMIC);
2445                 if (ret < 0)
2446                         return ret;
2447                 ULIST_ITER_INIT(&tmp_uiter);
2448                 while ((tmp_unode = ulist_next(tmp, &tmp_uiter))) {
2449                         struct btrfs_qgroup_list *glist;
2450
2451                         qg = unode_aux_to_qgroup(tmp_unode);
2452                         if (update_old)
2453                                 btrfs_qgroup_update_old_refcnt(qg, seq, 1);
2454                         else
2455                                 btrfs_qgroup_update_new_refcnt(qg, seq, 1);
2456                         list_for_each_entry(glist, &qg->groups, next_group) {
2457                                 ret = ulist_add(qgroups, glist->group->qgroupid,
2458                                                 qgroup_to_aux(glist->group),
2459                                                 GFP_ATOMIC);
2460                                 if (ret < 0)
2461                                         return ret;
2462                                 ret = ulist_add(tmp, glist->group->qgroupid,
2463                                                 qgroup_to_aux(glist->group),
2464                                                 GFP_ATOMIC);
2465                                 if (ret < 0)
2466                                         return ret;
2467                         }
2468                 }
2469         }
2470         return 0;
2471 }
2472
2473 /*
2474  * Update qgroup rfer/excl counters.
2475  * Rfer update is easy, codes can explain themselves.
2476  *
2477  * Excl update is tricky, the update is split into 2 parts.
2478  * Part 1: Possible exclusive <-> sharing detect:
2479  *      |       A       |       !A      |
2480  *  -------------------------------------
2481  *  B   |       *       |       -       |
2482  *  -------------------------------------
2483  *  !B  |       +       |       **      |
2484  *  -------------------------------------
2485  *
2486  * Conditions:
2487  * A:   cur_old_roots < nr_old_roots    (not exclusive before)
2488  * !A:  cur_old_roots == nr_old_roots   (possible exclusive before)
2489  * B:   cur_new_roots < nr_new_roots    (not exclusive now)
2490  * !B:  cur_new_roots == nr_new_roots   (possible exclusive now)
2491  *
2492  * Results:
2493  * +: Possible sharing -> exclusive     -: Possible exclusive -> sharing
2494  * *: Definitely not changed.           **: Possible unchanged.
2495  *
2496  * For !A and !B condition, the exception is cur_old/new_roots == 0 case.
2497  *
2498  * To make the logic clear, we first use condition A and B to split
2499  * combination into 4 results.
2500  *
2501  * Then, for result "+" and "-", check old/new_roots == 0 case, as in them
2502  * only on variant maybe 0.
2503  *
2504  * Lastly, check result **, since there are 2 variants maybe 0, split them
2505  * again(2x2).
2506  * But this time we don't need to consider other things, the codes and logic
2507  * is easy to understand now.
2508  */
2509 static int qgroup_update_counters(struct btrfs_fs_info *fs_info,
2510                                   struct ulist *qgroups,
2511                                   u64 nr_old_roots,
2512                                   u64 nr_new_roots,
2513                                   u64 num_bytes, u64 seq)
2514 {
2515         struct ulist_node *unode;
2516         struct ulist_iterator uiter;
2517         struct btrfs_qgroup *qg;
2518         u64 cur_new_count, cur_old_count;
2519
2520         ULIST_ITER_INIT(&uiter);
2521         while ((unode = ulist_next(qgroups, &uiter))) {
2522                 bool dirty = false;
2523
2524                 qg = unode_aux_to_qgroup(unode);
2525                 cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
2526                 cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
2527
2528                 trace_qgroup_update_counters(fs_info, qg, cur_old_count,
2529                                              cur_new_count);
2530
2531                 /* Rfer update part */
2532                 if (cur_old_count == 0 && cur_new_count > 0) {
2533                         qg->rfer += num_bytes;
2534                         qg->rfer_cmpr += num_bytes;
2535                         dirty = true;
2536                 }
2537                 if (cur_old_count > 0 && cur_new_count == 0) {
2538                         qg->rfer -= num_bytes;
2539                         qg->rfer_cmpr -= num_bytes;
2540                         dirty = true;
2541                 }
2542
2543                 /* Excl update part */
2544                 /* Exclusive/none -> shared case */
2545                 if (cur_old_count == nr_old_roots &&
2546                     cur_new_count < nr_new_roots) {
2547                         /* Exclusive -> shared */
2548                         if (cur_old_count != 0) {
2549                                 qg->excl -= num_bytes;
2550                                 qg->excl_cmpr -= num_bytes;
2551                                 dirty = true;
2552                         }
2553                 }
2554
2555                 /* Shared -> exclusive/none case */
2556                 if (cur_old_count < nr_old_roots &&
2557                     cur_new_count == nr_new_roots) {
2558                         /* Shared->exclusive */
2559                         if (cur_new_count != 0) {
2560                                 qg->excl += num_bytes;
2561                                 qg->excl_cmpr += num_bytes;
2562                                 dirty = true;
2563                         }
2564                 }
2565
2566                 /* Exclusive/none -> exclusive/none case */
2567                 if (cur_old_count == nr_old_roots &&
2568                     cur_new_count == nr_new_roots) {
2569                         if (cur_old_count == 0) {
2570                                 /* None -> exclusive/none */
2571
2572                                 if (cur_new_count != 0) {
2573                                         /* None -> exclusive */
2574                                         qg->excl += num_bytes;
2575                                         qg->excl_cmpr += num_bytes;
2576                                         dirty = true;
2577                                 }
2578                                 /* None -> none, nothing changed */
2579                         } else {
2580                                 /* Exclusive -> exclusive/none */
2581
2582                                 if (cur_new_count == 0) {
2583                                         /* Exclusive -> none */
2584                                         qg->excl -= num_bytes;
2585                                         qg->excl_cmpr -= num_bytes;
2586                                         dirty = true;
2587                                 }
2588                                 /* Exclusive -> exclusive, nothing changed */
2589                         }
2590                 }
2591
2592                 if (dirty)
2593                         qgroup_dirty(fs_info, qg);
2594         }
2595         return 0;
2596 }
2597
2598 /*
2599  * Check if the @roots potentially is a list of fs tree roots
2600  *
2601  * Return 0 for definitely not a fs/subvol tree roots ulist
2602  * Return 1 for possible fs/subvol tree roots in the list (considering an empty
2603  *          one as well)
2604  */
2605 static int maybe_fs_roots(struct ulist *roots)
2606 {
2607         struct ulist_node *unode;
2608         struct ulist_iterator uiter;
2609
2610         /* Empty one, still possible for fs roots */
2611         if (!roots || roots->nnodes == 0)
2612                 return 1;
2613
2614         ULIST_ITER_INIT(&uiter);
2615         unode = ulist_next(roots, &uiter);
2616         if (!unode)
2617                 return 1;
2618
2619         /*
2620          * If it contains fs tree roots, then it must belong to fs/subvol
2621          * trees.
2622          * If it contains a non-fs tree, it won't be shared with fs/subvol trees.
2623          */
2624         return is_fstree(unode->val);
2625 }
2626
2627 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
2628                                 u64 num_bytes, struct ulist *old_roots,
2629                                 struct ulist *new_roots)
2630 {
2631         struct btrfs_fs_info *fs_info = trans->fs_info;
2632         struct ulist *qgroups = NULL;
2633         struct ulist *tmp = NULL;
2634         u64 seq;
2635         u64 nr_new_roots = 0;
2636         u64 nr_old_roots = 0;
2637         int ret = 0;
2638
2639         /*
2640          * If quotas get disabled meanwhile, the resouces need to be freed and
2641          * we can't just exit here.
2642          */
2643         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2644                 goto out_free;
2645
2646         if (new_roots) {
2647                 if (!maybe_fs_roots(new_roots))
2648                         goto out_free;
2649                 nr_new_roots = new_roots->nnodes;
2650         }
2651         if (old_roots) {
2652                 if (!maybe_fs_roots(old_roots))
2653                         goto out_free;
2654                 nr_old_roots = old_roots->nnodes;
2655         }
2656
2657         /* Quick exit, either not fs tree roots, or won't affect any qgroup */
2658         if (nr_old_roots == 0 && nr_new_roots == 0)
2659                 goto out_free;
2660
2661         BUG_ON(!fs_info->quota_root);
2662
2663         trace_btrfs_qgroup_account_extent(fs_info, trans->transid, bytenr,
2664                                         num_bytes, nr_old_roots, nr_new_roots);
2665
2666         qgroups = ulist_alloc(GFP_NOFS);
2667         if (!qgroups) {
2668                 ret = -ENOMEM;
2669                 goto out_free;
2670         }
2671         tmp = ulist_alloc(GFP_NOFS);
2672         if (!tmp) {
2673                 ret = -ENOMEM;
2674                 goto out_free;
2675         }
2676
2677         mutex_lock(&fs_info->qgroup_rescan_lock);
2678         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
2679                 if (fs_info->qgroup_rescan_progress.objectid <= bytenr) {
2680                         mutex_unlock(&fs_info->qgroup_rescan_lock);
2681                         ret = 0;
2682                         goto out_free;
2683                 }
2684         }
2685         mutex_unlock(&fs_info->qgroup_rescan_lock);
2686
2687         spin_lock(&fs_info->qgroup_lock);
2688         seq = fs_info->qgroup_seq;
2689
2690         /* Update old refcnts using old_roots */
2691         ret = qgroup_update_refcnt(fs_info, old_roots, tmp, qgroups, seq,
2692                                    UPDATE_OLD);
2693         if (ret < 0)
2694                 goto out;
2695
2696         /* Update new refcnts using new_roots */
2697         ret = qgroup_update_refcnt(fs_info, new_roots, tmp, qgroups, seq,
2698                                    UPDATE_NEW);
2699         if (ret < 0)
2700                 goto out;
2701
2702         qgroup_update_counters(fs_info, qgroups, nr_old_roots, nr_new_roots,
2703                                num_bytes, seq);
2704
2705         /*
2706          * Bump qgroup_seq to avoid seq overlap
2707          */
2708         fs_info->qgroup_seq += max(nr_old_roots, nr_new_roots) + 1;
2709 out:
2710         spin_unlock(&fs_info->qgroup_lock);
2711 out_free:
2712         ulist_free(tmp);
2713         ulist_free(qgroups);
2714         ulist_free(old_roots);
2715         ulist_free(new_roots);
2716         return ret;
2717 }
2718
2719 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
2720 {
2721         struct btrfs_fs_info *fs_info = trans->fs_info;
2722         struct btrfs_qgroup_extent_record *record;
2723         struct btrfs_delayed_ref_root *delayed_refs;
2724         struct ulist *new_roots = NULL;
2725         struct rb_node *node;
2726         u64 num_dirty_extents = 0;
2727         u64 qgroup_to_skip;
2728         int ret = 0;
2729
2730         delayed_refs = &trans->transaction->delayed_refs;
2731         qgroup_to_skip = delayed_refs->qgroup_to_skip;
2732         while ((node = rb_first(&delayed_refs->dirty_extent_root))) {
2733                 record = rb_entry(node, struct btrfs_qgroup_extent_record,
2734                                   node);
2735
2736                 num_dirty_extents++;
2737                 trace_btrfs_qgroup_account_extents(fs_info, record);
2738
2739                 if (!ret) {
2740                         /*
2741                          * Old roots should be searched when inserting qgroup
2742                          * extent record
2743                          */
2744                         if (WARN_ON(!record->old_roots)) {
2745                                 /* Search commit root to find old_roots */
2746                                 ret = btrfs_find_all_roots(NULL, fs_info,
2747                                                 record->bytenr, 0,
2748                                                 &record->old_roots, false);
2749                                 if (ret < 0)
2750                                         goto cleanup;
2751                         }
2752
2753                         /* Free the reserved data space */
2754                         btrfs_qgroup_free_refroot(fs_info,
2755                                         record->data_rsv_refroot,
2756                                         record->data_rsv,
2757                                         BTRFS_QGROUP_RSV_DATA);
2758                         /*
2759                          * Use SEQ_LAST as time_seq to do special search, which
2760                          * doesn't lock tree or delayed_refs and search current
2761                          * root. It's safe inside commit_transaction().
2762                          */
2763                         ret = btrfs_find_all_roots(trans, fs_info,
2764                                 record->bytenr, SEQ_LAST, &new_roots, false);
2765                         if (ret < 0)
2766                                 goto cleanup;
2767                         if (qgroup_to_skip) {
2768                                 ulist_del(new_roots, qgroup_to_skip, 0);
2769                                 ulist_del(record->old_roots, qgroup_to_skip,
2770                                           0);
2771                         }
2772                         ret = btrfs_qgroup_account_extent(trans, record->bytenr,
2773                                                           record->num_bytes,
2774                                                           record->old_roots,
2775                                                           new_roots);
2776                         record->old_roots = NULL;
2777                         new_roots = NULL;
2778                 }
2779 cleanup:
2780                 ulist_free(record->old_roots);
2781                 ulist_free(new_roots);
2782                 new_roots = NULL;
2783                 rb_erase(node, &delayed_refs->dirty_extent_root);
2784                 kfree(record);
2785
2786         }
2787         trace_qgroup_num_dirty_extents(fs_info, trans->transid,
2788                                        num_dirty_extents);
2789         return ret;
2790 }
2791
2792 /*
2793  * Writes all changed qgroups to disk.
2794  * Called by the transaction commit path and the qgroup assign ioctl.
2795  */
2796 int btrfs_run_qgroups(struct btrfs_trans_handle *trans)
2797 {
2798         struct btrfs_fs_info *fs_info = trans->fs_info;
2799         int ret = 0;
2800
2801         /*
2802          * In case we are called from the qgroup assign ioctl, assert that we
2803          * are holding the qgroup_ioctl_lock, otherwise we can race with a quota
2804          * disable operation (ioctl) and access a freed quota root.
2805          */
2806         if (trans->transaction->state != TRANS_STATE_COMMIT_DOING)
2807                 lockdep_assert_held(&fs_info->qgroup_ioctl_lock);
2808
2809         if (!fs_info->quota_root)
2810                 return ret;
2811
2812         spin_lock(&fs_info->qgroup_lock);
2813         while (!list_empty(&fs_info->dirty_qgroups)) {
2814                 struct btrfs_qgroup *qgroup;
2815                 qgroup = list_first_entry(&fs_info->dirty_qgroups,
2816                                           struct btrfs_qgroup, dirty);
2817                 list_del_init(&qgroup->dirty);
2818                 spin_unlock(&fs_info->qgroup_lock);
2819                 ret = update_qgroup_info_item(trans, qgroup);
2820                 if (ret)
2821                         fs_info->qgroup_flags |=
2822                                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2823                 ret = update_qgroup_limit_item(trans, qgroup);
2824                 if (ret)
2825                         fs_info->qgroup_flags |=
2826                                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2827                 spin_lock(&fs_info->qgroup_lock);
2828         }
2829         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2830                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_ON;
2831         else
2832                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
2833         spin_unlock(&fs_info->qgroup_lock);
2834
2835         ret = update_qgroup_status_item(trans);
2836         if (ret)
2837                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
2838
2839         return ret;
2840 }
2841
2842 /*
2843  * Copy the accounting information between qgroups. This is necessary
2844  * when a snapshot or a subvolume is created. Throwing an error will
2845  * cause a transaction abort so we take extra care here to only error
2846  * when a readonly fs is a reasonable outcome.
2847  */
2848 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
2849                          u64 objectid, struct btrfs_qgroup_inherit *inherit)
2850 {
2851         int ret = 0;
2852         int i;
2853         u64 *i_qgroups;
2854         bool committing = false;
2855         struct btrfs_fs_info *fs_info = trans->fs_info;
2856         struct btrfs_root *quota_root;
2857         struct btrfs_qgroup *srcgroup;
2858         struct btrfs_qgroup *dstgroup;
2859         bool need_rescan = false;
2860         u32 level_size = 0;
2861         u64 nums;
2862
2863         /*
2864          * There are only two callers of this function.
2865          *
2866          * One in create_subvol() in the ioctl context, which needs to hold
2867          * the qgroup_ioctl_lock.
2868          *
2869          * The other one in create_pending_snapshot() where no other qgroup
2870          * code can modify the fs as they all need to either start a new trans
2871          * or hold a trans handler, thus we don't need to hold
2872          * qgroup_ioctl_lock.
2873          * This would avoid long and complex lock chain and make lockdep happy.
2874          */
2875         spin_lock(&fs_info->trans_lock);
2876         if (trans->transaction->state == TRANS_STATE_COMMIT_DOING)
2877                 committing = true;
2878         spin_unlock(&fs_info->trans_lock);
2879
2880         if (!committing)
2881                 mutex_lock(&fs_info->qgroup_ioctl_lock);
2882         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
2883                 goto out;
2884
2885         quota_root = fs_info->quota_root;
2886         if (!quota_root) {
2887                 ret = -EINVAL;
2888                 goto out;
2889         }
2890
2891         if (inherit) {
2892                 i_qgroups = (u64 *)(inherit + 1);
2893                 nums = inherit->num_qgroups + 2 * inherit->num_ref_copies +
2894                        2 * inherit->num_excl_copies;
2895                 for (i = 0; i < nums; ++i) {
2896                         srcgroup = find_qgroup_rb(fs_info, *i_qgroups);
2897
2898                         /*
2899                          * Zero out invalid groups so we can ignore
2900                          * them later.
2901                          */
2902                         if (!srcgroup ||
2903                             ((srcgroup->qgroupid >> 48) <= (objectid >> 48)))
2904                                 *i_qgroups = 0ULL;
2905
2906                         ++i_qgroups;
2907                 }
2908         }
2909
2910         /*
2911          * create a tracking group for the subvol itself
2912          */
2913         ret = add_qgroup_item(trans, quota_root, objectid);
2914         if (ret)
2915                 goto out;
2916
2917         /*
2918          * add qgroup to all inherited groups
2919          */
2920         if (inherit) {
2921                 i_qgroups = (u64 *)(inherit + 1);
2922                 for (i = 0; i < inherit->num_qgroups; ++i, ++i_qgroups) {
2923                         if (*i_qgroups == 0)
2924                                 continue;
2925                         ret = add_qgroup_relation_item(trans, objectid,
2926                                                        *i_qgroups);
2927                         if (ret && ret != -EEXIST)
2928                                 goto out;
2929                         ret = add_qgroup_relation_item(trans, *i_qgroups,
2930                                                        objectid);
2931                         if (ret && ret != -EEXIST)
2932                                 goto out;
2933                 }
2934                 ret = 0;
2935         }
2936
2937
2938         spin_lock(&fs_info->qgroup_lock);
2939
2940         dstgroup = add_qgroup_rb(fs_info, objectid);
2941         if (IS_ERR(dstgroup)) {
2942                 ret = PTR_ERR(dstgroup);
2943                 goto unlock;
2944         }
2945
2946         if (inherit && inherit->flags & BTRFS_QGROUP_INHERIT_SET_LIMITS) {
2947                 dstgroup->lim_flags = inherit->lim.flags;
2948                 dstgroup->max_rfer = inherit->lim.max_rfer;
2949                 dstgroup->max_excl = inherit->lim.max_excl;
2950                 dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
2951                 dstgroup->rsv_excl = inherit->lim.rsv_excl;
2952
2953                 qgroup_dirty(fs_info, dstgroup);
2954         }
2955
2956         if (srcid) {
2957                 srcgroup = find_qgroup_rb(fs_info, srcid);
2958                 if (!srcgroup)
2959                         goto unlock;
2960
2961                 /*
2962                  * We call inherit after we clone the root in order to make sure
2963                  * our counts don't go crazy, so at this point the only
2964                  * difference between the two roots should be the root node.
2965                  */
2966                 level_size = fs_info->nodesize;
2967                 dstgroup->rfer = srcgroup->rfer;
2968                 dstgroup->rfer_cmpr = srcgroup->rfer_cmpr;
2969                 dstgroup->excl = level_size;
2970                 dstgroup->excl_cmpr = level_size;
2971                 srcgroup->excl = level_size;
2972                 srcgroup->excl_cmpr = level_size;
2973
2974                 /* inherit the limit info */
2975                 dstgroup->lim_flags = srcgroup->lim_flags;
2976                 dstgroup->max_rfer = srcgroup->max_rfer;
2977                 dstgroup->max_excl = srcgroup->max_excl;
2978                 dstgroup->rsv_rfer = srcgroup->rsv_rfer;
2979                 dstgroup->rsv_excl = srcgroup->rsv_excl;
2980
2981                 qgroup_dirty(fs_info, dstgroup);
2982                 qgroup_dirty(fs_info, srcgroup);
2983         }
2984
2985         if (!inherit)
2986                 goto unlock;
2987
2988         i_qgroups = (u64 *)(inherit + 1);
2989         for (i = 0; i < inherit->num_qgroups; ++i) {
2990                 if (*i_qgroups) {
2991                         ret = add_relation_rb(fs_info, objectid, *i_qgroups);
2992                         if (ret)
2993                                 goto unlock;
2994                 }
2995                 ++i_qgroups;
2996
2997                 /*
2998                  * If we're doing a snapshot, and adding the snapshot to a new
2999                  * qgroup, the numbers are guaranteed to be incorrect.
3000                  */
3001                 if (srcid)
3002                         need_rescan = true;
3003         }
3004
3005         for (i = 0; i <  inherit->num_ref_copies; ++i, i_qgroups += 2) {
3006                 struct btrfs_qgroup *src;
3007                 struct btrfs_qgroup *dst;
3008
3009                 if (!i_qgroups[0] || !i_qgroups[1])
3010                         continue;
3011
3012                 src = find_qgroup_rb(fs_info, i_qgroups[0]);
3013                 dst = find_qgroup_rb(fs_info, i_qgroups[1]);
3014
3015                 if (!src || !dst) {
3016                         ret = -EINVAL;
3017                         goto unlock;
3018                 }
3019
3020                 dst->rfer = src->rfer - level_size;
3021                 dst->rfer_cmpr = src->rfer_cmpr - level_size;
3022
3023                 /* Manually tweaking numbers certainly needs a rescan */
3024                 need_rescan = true;
3025         }
3026         for (i = 0; i <  inherit->num_excl_copies; ++i, i_qgroups += 2) {
3027                 struct btrfs_qgroup *src;
3028                 struct btrfs_qgroup *dst;
3029
3030                 if (!i_qgroups[0] || !i_qgroups[1])
3031                         continue;
3032
3033                 src = find_qgroup_rb(fs_info, i_qgroups[0]);
3034                 dst = find_qgroup_rb(fs_info, i_qgroups[1]);
3035
3036                 if (!src || !dst) {
3037                         ret = -EINVAL;
3038                         goto unlock;
3039                 }
3040
3041                 dst->excl = src->excl + level_size;
3042                 dst->excl_cmpr = src->excl_cmpr + level_size;
3043                 need_rescan = true;
3044         }
3045
3046 unlock:
3047         spin_unlock(&fs_info->qgroup_lock);
3048         if (!ret)
3049                 ret = btrfs_sysfs_add_one_qgroup(fs_info, dstgroup);
3050 out:
3051         if (!committing)
3052                 mutex_unlock(&fs_info->qgroup_ioctl_lock);
3053         if (need_rescan)
3054                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3055         return ret;
3056 }
3057
3058 static bool qgroup_check_limits(const struct btrfs_qgroup *qg, u64 num_bytes)
3059 {
3060         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
3061             qgroup_rsv_total(qg) + (s64)qg->rfer + num_bytes > qg->max_rfer)
3062                 return false;
3063
3064         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
3065             qgroup_rsv_total(qg) + (s64)qg->excl + num_bytes > qg->max_excl)
3066                 return false;
3067
3068         return true;
3069 }
3070
3071 static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce,
3072                           enum btrfs_qgroup_rsv_type type)
3073 {
3074         struct btrfs_qgroup *qgroup;
3075         struct btrfs_fs_info *fs_info = root->fs_info;
3076         u64 ref_root = root->root_key.objectid;
3077         int ret = 0;
3078         struct ulist_node *unode;
3079         struct ulist_iterator uiter;
3080
3081         if (!is_fstree(ref_root))
3082                 return 0;
3083
3084         if (num_bytes == 0)
3085                 return 0;
3086
3087         if (test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags) &&
3088             capable(CAP_SYS_RESOURCE))
3089                 enforce = false;
3090
3091         spin_lock(&fs_info->qgroup_lock);
3092         if (!fs_info->quota_root)
3093                 goto out;
3094
3095         qgroup = find_qgroup_rb(fs_info, ref_root);
3096         if (!qgroup)
3097                 goto out;
3098
3099         /*
3100          * in a first step, we check all affected qgroups if any limits would
3101          * be exceeded
3102          */
3103         ulist_reinit(fs_info->qgroup_ulist);
3104         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
3105                         qgroup_to_aux(qgroup), GFP_ATOMIC);
3106         if (ret < 0)
3107                 goto out;
3108         ULIST_ITER_INIT(&uiter);
3109         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
3110                 struct btrfs_qgroup *qg;
3111                 struct btrfs_qgroup_list *glist;
3112
3113                 qg = unode_aux_to_qgroup(unode);
3114
3115                 if (enforce && !qgroup_check_limits(qg, num_bytes)) {
3116                         ret = -EDQUOT;
3117                         goto out;
3118                 }
3119
3120                 list_for_each_entry(glist, &qg->groups, next_group) {
3121                         ret = ulist_add(fs_info->qgroup_ulist,
3122                                         glist->group->qgroupid,
3123                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
3124                         if (ret < 0)
3125                                 goto out;
3126                 }
3127         }
3128         ret = 0;
3129         /*
3130          * no limits exceeded, now record the reservation into all qgroups
3131          */
3132         ULIST_ITER_INIT(&uiter);
3133         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
3134                 struct btrfs_qgroup *qg;
3135
3136                 qg = unode_aux_to_qgroup(unode);
3137
3138                 qgroup_rsv_add(fs_info, qg, num_bytes, type);
3139         }
3140
3141 out:
3142         spin_unlock(&fs_info->qgroup_lock);
3143         return ret;
3144 }
3145
3146 /*
3147  * Free @num_bytes of reserved space with @type for qgroup.  (Normally level 0
3148  * qgroup).
3149  *
3150  * Will handle all higher level qgroup too.
3151  *
3152  * NOTE: If @num_bytes is (u64)-1, this means to free all bytes of this qgroup.
3153  * This special case is only used for META_PERTRANS type.
3154  */
3155 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
3156                                u64 ref_root, u64 num_bytes,
3157                                enum btrfs_qgroup_rsv_type type)
3158 {
3159         struct btrfs_qgroup *qgroup;
3160         struct ulist_node *unode;
3161         struct ulist_iterator uiter;
3162         int ret = 0;
3163
3164         if (!is_fstree(ref_root))
3165                 return;
3166
3167         if (num_bytes == 0)
3168                 return;
3169
3170         if (num_bytes == (u64)-1 && type != BTRFS_QGROUP_RSV_META_PERTRANS) {
3171                 WARN(1, "%s: Invalid type to free", __func__);
3172                 return;
3173         }
3174         spin_lock(&fs_info->qgroup_lock);
3175
3176         if (!fs_info->quota_root)
3177                 goto out;
3178
3179         qgroup = find_qgroup_rb(fs_info, ref_root);
3180         if (!qgroup)
3181                 goto out;
3182
3183         if (num_bytes == (u64)-1)
3184                 /*
3185                  * We're freeing all pertrans rsv, get reserved value from
3186                  * level 0 qgroup as real num_bytes to free.
3187                  */
3188                 num_bytes = qgroup->rsv.values[type];
3189
3190         ulist_reinit(fs_info->qgroup_ulist);
3191         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
3192                         qgroup_to_aux(qgroup), GFP_ATOMIC);
3193         if (ret < 0)
3194                 goto out;
3195         ULIST_ITER_INIT(&uiter);
3196         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
3197                 struct btrfs_qgroup *qg;
3198                 struct btrfs_qgroup_list *glist;
3199
3200                 qg = unode_aux_to_qgroup(unode);
3201
3202                 qgroup_rsv_release(fs_info, qg, num_bytes, type);
3203
3204                 list_for_each_entry(glist, &qg->groups, next_group) {
3205                         ret = ulist_add(fs_info->qgroup_ulist,
3206                                         glist->group->qgroupid,
3207                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
3208                         if (ret < 0)
3209                                 goto out;
3210                 }
3211         }
3212
3213 out:
3214         spin_unlock(&fs_info->qgroup_lock);
3215 }
3216
3217 /*
3218  * Check if the leaf is the last leaf. Which means all node pointers
3219  * are at their last position.
3220  */
3221 static bool is_last_leaf(struct btrfs_path *path)
3222 {
3223         int i;
3224
3225         for (i = 1; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
3226                 if (path->slots[i] != btrfs_header_nritems(path->nodes[i]) - 1)
3227                         return false;
3228         }
3229         return true;
3230 }
3231
3232 /*
3233  * returns < 0 on error, 0 when more leafs are to be scanned.
3234  * returns 1 when done.
3235  */
3236 static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
3237                               struct btrfs_path *path)
3238 {
3239         struct btrfs_fs_info *fs_info = trans->fs_info;
3240         struct btrfs_key found;
3241         struct extent_buffer *scratch_leaf = NULL;
3242         struct ulist *roots = NULL;
3243         u64 num_bytes;
3244         bool done;
3245         int slot;
3246         int ret;
3247
3248         mutex_lock(&fs_info->qgroup_rescan_lock);
3249         ret = btrfs_search_slot_for_read(fs_info->extent_root,
3250                                          &fs_info->qgroup_rescan_progress,
3251                                          path, 1, 0);
3252
3253         btrfs_debug(fs_info,
3254                 "current progress key (%llu %u %llu), search_slot ret %d",
3255                 fs_info->qgroup_rescan_progress.objectid,
3256                 fs_info->qgroup_rescan_progress.type,
3257                 fs_info->qgroup_rescan_progress.offset, ret);
3258
3259         if (ret) {
3260                 /*
3261                  * The rescan is about to end, we will not be scanning any
3262                  * further blocks. We cannot unset the RESCAN flag here, because
3263                  * we want to commit the transaction if everything went well.
3264                  * To make the live accounting work in this phase, we set our
3265                  * scan progress pointer such that every real extent objectid
3266                  * will be smaller.
3267                  */
3268                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3269                 btrfs_release_path(path);
3270                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3271                 return ret;
3272         }
3273         done = is_last_leaf(path);
3274
3275         btrfs_item_key_to_cpu(path->nodes[0], &found,
3276                               btrfs_header_nritems(path->nodes[0]) - 1);
3277         fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
3278
3279         scratch_leaf = btrfs_clone_extent_buffer(path->nodes[0]);
3280         if (!scratch_leaf) {
3281                 ret = -ENOMEM;
3282                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3283                 goto out;
3284         }
3285         slot = path->slots[0];
3286         btrfs_release_path(path);
3287         mutex_unlock(&fs_info->qgroup_rescan_lock);
3288
3289         for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
3290                 btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
3291                 if (found.type != BTRFS_EXTENT_ITEM_KEY &&
3292                     found.type != BTRFS_METADATA_ITEM_KEY)
3293                         continue;
3294                 if (found.type == BTRFS_METADATA_ITEM_KEY)
3295                         num_bytes = fs_info->nodesize;
3296                 else
3297                         num_bytes = found.offset;
3298
3299                 ret = btrfs_find_all_roots(NULL, fs_info, found.objectid, 0,
3300                                            &roots, false);
3301                 if (ret < 0)
3302                         goto out;
3303                 /* For rescan, just pass old_roots as NULL */
3304                 ret = btrfs_qgroup_account_extent(trans, found.objectid,
3305                                                   num_bytes, NULL, roots);
3306                 if (ret < 0)
3307                         goto out;
3308         }
3309 out:
3310         if (scratch_leaf)
3311                 free_extent_buffer(scratch_leaf);
3312
3313         if (done && !ret) {
3314                 ret = 1;
3315                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3316         }
3317         return ret;
3318 }
3319
3320 static bool rescan_should_stop(struct btrfs_fs_info *fs_info)
3321 {
3322         return btrfs_fs_closing(fs_info) ||
3323                 test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state) ||
3324                 !test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
3325 }
3326
3327 static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
3328 {
3329         struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
3330                                                      qgroup_rescan_work);
3331         struct btrfs_path *path;
3332         struct btrfs_trans_handle *trans = NULL;
3333         int err = -ENOMEM;
3334         int ret = 0;
3335         bool stopped = false;
3336         bool did_leaf_rescans = false;
3337
3338         path = btrfs_alloc_path();
3339         if (!path)
3340                 goto out;
3341         /*
3342          * Rescan should only search for commit root, and any later difference
3343          * should be recorded by qgroup
3344          */
3345         path->search_commit_root = 1;
3346         path->skip_locking = 1;
3347
3348         err = 0;
3349         while (!err && !(stopped = rescan_should_stop(fs_info))) {
3350                 trans = btrfs_start_transaction(fs_info->fs_root, 0);
3351                 if (IS_ERR(trans)) {
3352                         err = PTR_ERR(trans);
3353                         break;
3354                 }
3355
3356                 err = qgroup_rescan_leaf(trans, path);
3357                 did_leaf_rescans = true;
3358
3359                 if (err > 0)
3360                         btrfs_commit_transaction(trans);
3361                 else
3362                         btrfs_end_transaction(trans);
3363         }
3364
3365 out:
3366         btrfs_free_path(path);
3367
3368         mutex_lock(&fs_info->qgroup_rescan_lock);
3369         if (err > 0 &&
3370             fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
3371                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3372         } else if (err < 0 || stopped) {
3373                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3374         }
3375         mutex_unlock(&fs_info->qgroup_rescan_lock);
3376
3377         /*
3378          * Only update status, since the previous part has already updated the
3379          * qgroup info, and only if we did any actual work. This also prevents
3380          * race with a concurrent quota disable, which has already set
3381          * fs_info->quota_root to NULL and cleared BTRFS_FS_QUOTA_ENABLED at
3382          * btrfs_quota_disable().
3383          */
3384         if (did_leaf_rescans) {
3385                 trans = btrfs_start_transaction(fs_info->quota_root, 1);
3386                 if (IS_ERR(trans)) {
3387                         err = PTR_ERR(trans);
3388                         trans = NULL;
3389                         btrfs_err(fs_info,
3390                                   "fail to start transaction for status update: %d",
3391                                   err);
3392                 }
3393         } else {
3394                 trans = NULL;
3395         }
3396
3397         mutex_lock(&fs_info->qgroup_rescan_lock);
3398         if (!stopped)
3399                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3400         if (trans) {
3401                 ret = update_qgroup_status_item(trans);
3402                 if (ret < 0) {
3403                         err = ret;
3404                         btrfs_err(fs_info, "fail to update qgroup status: %d",
3405                                   err);
3406                 }
3407         }
3408         fs_info->qgroup_rescan_running = false;
3409         complete_all(&fs_info->qgroup_rescan_completion);
3410         mutex_unlock(&fs_info->qgroup_rescan_lock);
3411
3412         if (!trans)
3413                 return;
3414
3415         btrfs_end_transaction(trans);
3416
3417         if (stopped) {
3418                 btrfs_info(fs_info, "qgroup scan paused");
3419         } else if (err >= 0) {
3420                 btrfs_info(fs_info, "qgroup scan completed%s",
3421                         err > 0 ? " (inconsistency flag cleared)" : "");
3422         } else {
3423                 btrfs_err(fs_info, "qgroup scan failed with %d", err);
3424         }
3425 }
3426
3427 /*
3428  * Checks that (a) no rescan is running and (b) quota is enabled. Allocates all
3429  * memory required for the rescan context.
3430  */
3431 static int
3432 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
3433                    int init_flags)
3434 {
3435         int ret = 0;
3436
3437         if (!init_flags) {
3438                 /* we're resuming qgroup rescan at mount time */
3439                 if (!(fs_info->qgroup_flags &
3440                       BTRFS_QGROUP_STATUS_FLAG_RESCAN)) {
3441                         btrfs_warn(fs_info,
3442                         "qgroup rescan init failed, qgroup rescan is not queued");
3443                         ret = -EINVAL;
3444                 } else if (!(fs_info->qgroup_flags &
3445                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3446                         btrfs_warn(fs_info,
3447                         "qgroup rescan init failed, qgroup is not enabled");
3448                         ret = -EINVAL;
3449                 }
3450
3451                 if (ret)
3452                         return ret;
3453         }
3454
3455         mutex_lock(&fs_info->qgroup_rescan_lock);
3456
3457         if (init_flags) {
3458                 if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
3459                         btrfs_warn(fs_info,
3460                                    "qgroup rescan is already in progress");
3461                         ret = -EINPROGRESS;
3462                 } else if (!(fs_info->qgroup_flags &
3463                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3464                         btrfs_warn(fs_info,
3465                         "qgroup rescan init failed, qgroup is not enabled");
3466                         ret = -EINVAL;
3467                 } else if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
3468                         /* Quota disable is in progress */
3469                         ret = -EBUSY;
3470                 }
3471
3472                 if (ret) {
3473                         mutex_unlock(&fs_info->qgroup_rescan_lock);
3474                         return ret;
3475                 }
3476                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3477         }
3478
3479         memset(&fs_info->qgroup_rescan_progress, 0,
3480                 sizeof(fs_info->qgroup_rescan_progress));
3481         fs_info->qgroup_rescan_progress.objectid = progress_objectid;
3482         init_completion(&fs_info->qgroup_rescan_completion);
3483         mutex_unlock(&fs_info->qgroup_rescan_lock);
3484
3485         btrfs_init_work(&fs_info->qgroup_rescan_work,
3486                         btrfs_qgroup_rescan_worker, NULL, NULL);
3487         return 0;
3488 }
3489
3490 static void
3491 qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info)
3492 {
3493         struct rb_node *n;
3494         struct btrfs_qgroup *qgroup;
3495
3496         spin_lock(&fs_info->qgroup_lock);
3497         /* clear all current qgroup tracking information */
3498         for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
3499                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
3500                 qgroup->rfer = 0;
3501                 qgroup->rfer_cmpr = 0;
3502                 qgroup->excl = 0;
3503                 qgroup->excl_cmpr = 0;
3504                 qgroup_dirty(fs_info, qgroup);
3505         }
3506         spin_unlock(&fs_info->qgroup_lock);
3507 }
3508
3509 int
3510 btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
3511 {
3512         int ret = 0;
3513         struct btrfs_trans_handle *trans;
3514
3515         ret = qgroup_rescan_init(fs_info, 0, 1);
3516         if (ret)
3517                 return ret;
3518
3519         /*
3520          * We have set the rescan_progress to 0, which means no more
3521          * delayed refs will be accounted by btrfs_qgroup_account_ref.
3522          * However, btrfs_qgroup_account_ref may be right after its call
3523          * to btrfs_find_all_roots, in which case it would still do the
3524          * accounting.
3525          * To solve this, we're committing the transaction, which will
3526          * ensure we run all delayed refs and only after that, we are
3527          * going to clear all tracking information for a clean start.
3528          */
3529
3530         trans = btrfs_join_transaction(fs_info->fs_root);
3531         if (IS_ERR(trans)) {
3532                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3533                 return PTR_ERR(trans);
3534         }
3535         ret = btrfs_commit_transaction(trans);
3536         if (ret) {
3537                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3538                 return ret;
3539         }
3540
3541         qgroup_rescan_zero_tracking(fs_info);
3542
3543         mutex_lock(&fs_info->qgroup_rescan_lock);
3544         fs_info->qgroup_rescan_running = true;
3545         btrfs_queue_work(fs_info->qgroup_rescan_workers,
3546                          &fs_info->qgroup_rescan_work);
3547         mutex_unlock(&fs_info->qgroup_rescan_lock);
3548
3549         return 0;
3550 }
3551
3552 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
3553                                      bool interruptible)
3554 {
3555         int running;
3556         int ret = 0;
3557
3558         mutex_lock(&fs_info->qgroup_rescan_lock);
3559         running = fs_info->qgroup_rescan_running;
3560         mutex_unlock(&fs_info->qgroup_rescan_lock);
3561
3562         if (!running)
3563                 return 0;
3564
3565         if (interruptible)
3566                 ret = wait_for_completion_interruptible(
3567                                         &fs_info->qgroup_rescan_completion);
3568         else
3569                 wait_for_completion(&fs_info->qgroup_rescan_completion);
3570
3571         return ret;
3572 }
3573
3574 /*
3575  * this is only called from open_ctree where we're still single threaded, thus
3576  * locking is omitted here.
3577  */
3578 void
3579 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
3580 {
3581         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
3582                 mutex_lock(&fs_info->qgroup_rescan_lock);
3583                 fs_info->qgroup_rescan_running = true;
3584                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
3585                                  &fs_info->qgroup_rescan_work);
3586                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3587         }
3588 }
3589
3590 #define rbtree_iterate_from_safe(node, next, start)                             \
3591        for (node = start; node && ({ next = rb_next(node); 1;}); node = next)
3592
3593 static int qgroup_unreserve_range(struct btrfs_inode *inode,
3594                                   struct extent_changeset *reserved, u64 start,
3595                                   u64 len)
3596 {
3597         struct rb_node *node;
3598         struct rb_node *next;
3599         struct ulist_node *entry;
3600         int ret = 0;
3601
3602         node = reserved->range_changed.root.rb_node;
3603         if (!node)
3604                 return 0;
3605         while (node) {
3606                 entry = rb_entry(node, struct ulist_node, rb_node);
3607                 if (entry->val < start)
3608                         node = node->rb_right;
3609                 else
3610                         node = node->rb_left;
3611         }
3612
3613         if (entry->val > start && rb_prev(&entry->rb_node))
3614                 entry = rb_entry(rb_prev(&entry->rb_node), struct ulist_node,
3615                                  rb_node);
3616
3617         rbtree_iterate_from_safe(node, next, &entry->rb_node) {
3618                 u64 entry_start;
3619                 u64 entry_end;
3620                 u64 entry_len;
3621                 int clear_ret;
3622
3623                 entry = rb_entry(node, struct ulist_node, rb_node);
3624                 entry_start = entry->val;
3625                 entry_end = entry->aux;
3626                 entry_len = entry_end - entry_start + 1;
3627
3628                 if (entry_start >= start + len)
3629                         break;
3630                 if (entry_start + entry_len <= start)
3631                         continue;
3632                 /*
3633                  * Now the entry is in [start, start + len), revert the
3634                  * EXTENT_QGROUP_RESERVED bit.
3635                  */
3636                 clear_ret = clear_extent_bits(&inode->io_tree, entry_start,
3637                                               entry_end, EXTENT_QGROUP_RESERVED);
3638                 if (!ret && clear_ret < 0)
3639                         ret = clear_ret;
3640
3641                 ulist_del(&reserved->range_changed, entry->val, entry->aux);
3642                 if (likely(reserved->bytes_changed >= entry_len)) {
3643                         reserved->bytes_changed -= entry_len;
3644                 } else {
3645                         WARN_ON(1);
3646                         reserved->bytes_changed = 0;
3647                 }
3648         }
3649
3650         return ret;
3651 }
3652
3653 /*
3654  * Try to free some space for qgroup.
3655  *
3656  * For qgroup, there are only 3 ways to free qgroup space:
3657  * - Flush nodatacow write
3658  *   Any nodatacow write will free its reserved data space at run_delalloc_range().
3659  *   In theory, we should only flush nodatacow inodes, but it's not yet
3660  *   possible, so we need to flush the whole root.
3661  *
3662  * - Wait for ordered extents
3663  *   When ordered extents are finished, their reserved metadata is finally
3664  *   converted to per_trans status, which can be freed by later commit
3665  *   transaction.
3666  *
3667  * - Commit transaction
3668  *   This would free the meta_per_trans space.
3669  *   In theory this shouldn't provide much space, but any more qgroup space
3670  *   is needed.
3671  */
3672 static int try_flush_qgroup(struct btrfs_root *root)
3673 {
3674         struct btrfs_trans_handle *trans;
3675         int ret;
3676         bool can_commit = true;
3677
3678         /*
3679          * If current process holds a transaction, we shouldn't flush, as we
3680          * assume all space reservation happens before a transaction handle is
3681          * held.
3682          *
3683          * But there are cases like btrfs_delayed_item_reserve_metadata() where
3684          * we try to reserve space with one transction handle already held.
3685          * In that case we can't commit transaction, but at least try to end it
3686          * and hope the started data writes can free some space.
3687          */
3688         if (current->journal_info &&
3689             current->journal_info != BTRFS_SEND_TRANS_STUB)
3690                 can_commit = false;
3691
3692         /*
3693          * We don't want to run flush again and again, so if there is a running
3694          * one, we won't try to start a new flush, but exit directly.
3695          */
3696         if (test_and_set_bit(BTRFS_ROOT_QGROUP_FLUSHING, &root->state)) {
3697                 /*
3698                  * We are already holding a transaction, thus we can block other
3699                  * threads from flushing.  So exit right now. This increases
3700                  * the chance of EDQUOT for heavy load and near limit cases.
3701                  * But we can argue that if we're already near limit, EDQUOT is
3702                  * unavoidable anyway.
3703                  */
3704                 if (!can_commit)
3705                         return 0;
3706
3707                 wait_event(root->qgroup_flush_wait,
3708                         !test_bit(BTRFS_ROOT_QGROUP_FLUSHING, &root->state));
3709                 return 0;
3710         }
3711
3712         ret = btrfs_start_delalloc_snapshot(root);
3713         if (ret < 0)
3714                 goto out;
3715         btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
3716
3717         trans = btrfs_join_transaction(root);
3718         if (IS_ERR(trans)) {
3719                 ret = PTR_ERR(trans);
3720                 goto out;
3721         }
3722
3723         if (can_commit)
3724                 ret = btrfs_commit_transaction(trans);
3725         else
3726                 ret = btrfs_end_transaction(trans);
3727 out:
3728         clear_bit(BTRFS_ROOT_QGROUP_FLUSHING, &root->state);
3729         wake_up(&root->qgroup_flush_wait);
3730         return ret;
3731 }
3732
3733 static int qgroup_reserve_data(struct btrfs_inode *inode,
3734                         struct extent_changeset **reserved_ret, u64 start,
3735                         u64 len)
3736 {
3737         struct btrfs_root *root = inode->root;
3738         struct extent_changeset *reserved;
3739         bool new_reserved = false;
3740         u64 orig_reserved;
3741         u64 to_reserve;
3742         int ret;
3743
3744         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags) ||
3745             !is_fstree(root->root_key.objectid) || len == 0)
3746                 return 0;
3747
3748         /* @reserved parameter is mandatory for qgroup */
3749         if (WARN_ON(!reserved_ret))
3750                 return -EINVAL;
3751         if (!*reserved_ret) {
3752                 new_reserved = true;
3753                 *reserved_ret = extent_changeset_alloc();
3754                 if (!*reserved_ret)
3755                         return -ENOMEM;
3756         }
3757         reserved = *reserved_ret;
3758         /* Record already reserved space */
3759         orig_reserved = reserved->bytes_changed;
3760         ret = set_record_extent_bits(&inode->io_tree, start,
3761                         start + len -1, EXTENT_QGROUP_RESERVED, reserved);
3762
3763         /* Newly reserved space */
3764         to_reserve = reserved->bytes_changed - orig_reserved;
3765         trace_btrfs_qgroup_reserve_data(&inode->vfs_inode, start, len,
3766                                         to_reserve, QGROUP_RESERVE);
3767         if (ret < 0)
3768                 goto out;
3769         ret = qgroup_reserve(root, to_reserve, true, BTRFS_QGROUP_RSV_DATA);
3770         if (ret < 0)
3771                 goto cleanup;
3772
3773         return ret;
3774
3775 cleanup:
3776         qgroup_unreserve_range(inode, reserved, start, len);
3777 out:
3778         if (new_reserved) {
3779                 extent_changeset_release(reserved);
3780                 kfree(reserved);
3781                 *reserved_ret = NULL;
3782         }
3783         return ret;
3784 }
3785
3786 /*
3787  * Reserve qgroup space for range [start, start + len).
3788  *
3789  * This function will either reserve space from related qgroups or do nothing
3790  * if the range is already reserved.
3791  *
3792  * Return 0 for successful reservation
3793  * Return <0 for error (including -EQUOT)
3794  *
3795  * NOTE: This function may sleep for memory allocation, dirty page flushing and
3796  *       commit transaction. So caller should not hold any dirty page locked.
3797  */
3798 int btrfs_qgroup_reserve_data(struct btrfs_inode *inode,
3799                         struct extent_changeset **reserved_ret, u64 start,
3800                         u64 len)
3801 {
3802         int ret;
3803
3804         ret = qgroup_reserve_data(inode, reserved_ret, start, len);
3805         if (ret <= 0 && ret != -EDQUOT)
3806                 return ret;
3807
3808         ret = try_flush_qgroup(inode->root);
3809         if (ret < 0)
3810                 return ret;
3811         return qgroup_reserve_data(inode, reserved_ret, start, len);
3812 }
3813
3814 /* Free ranges specified by @reserved, normally in error path */
3815 static int qgroup_free_reserved_data(struct btrfs_inode *inode,
3816                         struct extent_changeset *reserved, u64 start, u64 len)
3817 {
3818         struct btrfs_root *root = inode->root;
3819         struct ulist_node *unode;
3820         struct ulist_iterator uiter;
3821         struct extent_changeset changeset;
3822         int freed = 0;
3823         int ret;
3824
3825         extent_changeset_init(&changeset);
3826         len = round_up(start + len, root->fs_info->sectorsize);
3827         start = round_down(start, root->fs_info->sectorsize);
3828
3829         ULIST_ITER_INIT(&uiter);
3830         while ((unode = ulist_next(&reserved->range_changed, &uiter))) {
3831                 u64 range_start = unode->val;
3832                 /* unode->aux is the inclusive end */
3833                 u64 range_len = unode->aux - range_start + 1;
3834                 u64 free_start;
3835                 u64 free_len;
3836
3837                 extent_changeset_release(&changeset);
3838
3839                 /* Only free range in range [start, start + len) */
3840                 if (range_start >= start + len ||
3841                     range_start + range_len <= start)
3842                         continue;
3843                 free_start = max(range_start, start);
3844                 free_len = min(start + len, range_start + range_len) -
3845                            free_start;
3846                 /*
3847                  * TODO: To also modify reserved->ranges_reserved to reflect
3848                  * the modification.
3849                  *
3850                  * However as long as we free qgroup reserved according to
3851                  * EXTENT_QGROUP_RESERVED, we won't double free.
3852                  * So not need to rush.
3853                  */
3854                 ret = clear_record_extent_bits(&inode->io_tree, free_start,
3855                                 free_start + free_len - 1,
3856                                 EXTENT_QGROUP_RESERVED, &changeset);
3857                 if (ret < 0)
3858                         goto out;
3859                 freed += changeset.bytes_changed;
3860         }
3861         btrfs_qgroup_free_refroot(root->fs_info, root->root_key.objectid, freed,
3862                                   BTRFS_QGROUP_RSV_DATA);
3863         ret = freed;
3864 out:
3865         extent_changeset_release(&changeset);
3866         return ret;
3867 }
3868
3869 static int __btrfs_qgroup_release_data(struct btrfs_inode *inode,
3870                         struct extent_changeset *reserved, u64 start, u64 len,
3871                         int free)
3872 {
3873         struct extent_changeset changeset;
3874         int trace_op = QGROUP_RELEASE;
3875         int ret;
3876
3877         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &inode->root->fs_info->flags))
3878                 return 0;
3879
3880         /* In release case, we shouldn't have @reserved */
3881         WARN_ON(!free && reserved);
3882         if (free && reserved)
3883                 return qgroup_free_reserved_data(inode, reserved, start, len);
3884         extent_changeset_init(&changeset);
3885         ret = clear_record_extent_bits(&inode->io_tree, start, start + len -1,
3886                                        EXTENT_QGROUP_RESERVED, &changeset);
3887         if (ret < 0)
3888                 goto out;
3889
3890         if (free)
3891                 trace_op = QGROUP_FREE;
3892         trace_btrfs_qgroup_release_data(&inode->vfs_inode, start, len,
3893                                         changeset.bytes_changed, trace_op);
3894         if (free)
3895                 btrfs_qgroup_free_refroot(inode->root->fs_info,
3896                                 inode->root->root_key.objectid,
3897                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
3898         ret = changeset.bytes_changed;
3899 out:
3900         extent_changeset_release(&changeset);
3901         return ret;
3902 }
3903
3904 /*
3905  * Free a reserved space range from io_tree and related qgroups
3906  *
3907  * Should be called when a range of pages get invalidated before reaching disk.
3908  * Or for error cleanup case.
3909  * if @reserved is given, only reserved range in [@start, @start + @len) will
3910  * be freed.
3911  *
3912  * For data written to disk, use btrfs_qgroup_release_data().
3913  *
3914  * NOTE: This function may sleep for memory allocation.
3915  */
3916 int btrfs_qgroup_free_data(struct btrfs_inode *inode,
3917                         struct extent_changeset *reserved, u64 start, u64 len)
3918 {
3919         return __btrfs_qgroup_release_data(inode, reserved, start, len, 1);
3920 }
3921
3922 /*
3923  * Release a reserved space range from io_tree only.
3924  *
3925  * Should be called when a range of pages get written to disk and corresponding
3926  * FILE_EXTENT is inserted into corresponding root.
3927  *
3928  * Since new qgroup accounting framework will only update qgroup numbers at
3929  * commit_transaction() time, its reserved space shouldn't be freed from
3930  * related qgroups.
3931  *
3932  * But we should release the range from io_tree, to allow further write to be
3933  * COWed.
3934  *
3935  * NOTE: This function may sleep for memory allocation.
3936  */
3937 int btrfs_qgroup_release_data(struct btrfs_inode *inode, u64 start, u64 len)
3938 {
3939         return __btrfs_qgroup_release_data(inode, NULL, start, len, 0);
3940 }
3941
3942 static void add_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3943                               enum btrfs_qgroup_rsv_type type)
3944 {
3945         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3946             type != BTRFS_QGROUP_RSV_META_PERTRANS)
3947                 return;
3948         if (num_bytes == 0)
3949                 return;
3950
3951         spin_lock(&root->qgroup_meta_rsv_lock);
3952         if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
3953                 root->qgroup_meta_rsv_prealloc += num_bytes;
3954         else
3955                 root->qgroup_meta_rsv_pertrans += num_bytes;
3956         spin_unlock(&root->qgroup_meta_rsv_lock);
3957 }
3958
3959 static int sub_root_meta_rsv(struct btrfs_root *root, int num_bytes,
3960                              enum btrfs_qgroup_rsv_type type)
3961 {
3962         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
3963             type != BTRFS_QGROUP_RSV_META_PERTRANS)
3964                 return 0;
3965         if (num_bytes == 0)
3966                 return 0;
3967
3968         spin_lock(&root->qgroup_meta_rsv_lock);
3969         if (type == BTRFS_QGROUP_RSV_META_PREALLOC) {
3970                 num_bytes = min_t(u64, root->qgroup_meta_rsv_prealloc,
3971                                   num_bytes);
3972                 root->qgroup_meta_rsv_prealloc -= num_bytes;
3973         } else {
3974                 num_bytes = min_t(u64, root->qgroup_meta_rsv_pertrans,
3975                                   num_bytes);
3976                 root->qgroup_meta_rsv_pertrans -= num_bytes;
3977         }
3978         spin_unlock(&root->qgroup_meta_rsv_lock);
3979         return num_bytes;
3980 }
3981
3982 int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
3983                               enum btrfs_qgroup_rsv_type type, bool enforce)
3984 {
3985         struct btrfs_fs_info *fs_info = root->fs_info;
3986         int ret;
3987
3988         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
3989             !is_fstree(root->root_key.objectid) || num_bytes == 0)
3990                 return 0;
3991
3992         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
3993         trace_qgroup_meta_reserve(root, (s64)num_bytes, type);
3994         ret = qgroup_reserve(root, num_bytes, enforce, type);
3995         if (ret < 0)
3996                 return ret;
3997         /*
3998          * Record what we have reserved into root.
3999          *
4000          * To avoid quota disabled->enabled underflow.
4001          * In that case, we may try to free space we haven't reserved
4002          * (since quota was disabled), so record what we reserved into root.
4003          * And ensure later release won't underflow this number.
4004          */
4005         add_root_meta_rsv(root, num_bytes, type);
4006         return ret;
4007 }
4008
4009 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
4010                                 enum btrfs_qgroup_rsv_type type, bool enforce)
4011 {
4012         int ret;
4013
4014         ret = btrfs_qgroup_reserve_meta(root, num_bytes, type, enforce);
4015         if (ret <= 0 && ret != -EDQUOT)
4016                 return ret;
4017
4018         ret = try_flush_qgroup(root);
4019         if (ret < 0)
4020                 return ret;
4021         return btrfs_qgroup_reserve_meta(root, num_bytes, type, enforce);
4022 }
4023
4024 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root)
4025 {
4026         struct btrfs_fs_info *fs_info = root->fs_info;
4027
4028         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
4029             !is_fstree(root->root_key.objectid))
4030                 return;
4031
4032         /* TODO: Update trace point to handle such free */
4033         trace_qgroup_meta_free_all_pertrans(root);
4034         /* Special value -1 means to free all reserved space */
4035         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid, (u64)-1,
4036                                   BTRFS_QGROUP_RSV_META_PERTRANS);
4037 }
4038
4039 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
4040                               enum btrfs_qgroup_rsv_type type)
4041 {
4042         struct btrfs_fs_info *fs_info = root->fs_info;
4043
4044         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
4045             !is_fstree(root->root_key.objectid))
4046                 return;
4047
4048         /*
4049          * reservation for META_PREALLOC can happen before quota is enabled,
4050          * which can lead to underflow.
4051          * Here ensure we will only free what we really have reserved.
4052          */
4053         num_bytes = sub_root_meta_rsv(root, num_bytes, type);
4054         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
4055         trace_qgroup_meta_reserve(root, -(s64)num_bytes, type);
4056         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
4057                                   num_bytes, type);
4058 }
4059
4060 static void qgroup_convert_meta(struct btrfs_fs_info *fs_info, u64 ref_root,
4061                                 int num_bytes)
4062 {
4063         struct btrfs_qgroup *qgroup;
4064         struct ulist_node *unode;
4065         struct ulist_iterator uiter;
4066         int ret = 0;
4067
4068         if (num_bytes == 0)
4069                 return;
4070         if (!fs_info->quota_root)
4071                 return;
4072
4073         spin_lock(&fs_info->qgroup_lock);
4074         qgroup = find_qgroup_rb(fs_info, ref_root);
4075         if (!qgroup)
4076                 goto out;
4077         ulist_reinit(fs_info->qgroup_ulist);
4078         ret = ulist_add(fs_info->qgroup_ulist, qgroup->qgroupid,
4079                        qgroup_to_aux(qgroup), GFP_ATOMIC);
4080         if (ret < 0)
4081                 goto out;
4082         ULIST_ITER_INIT(&uiter);
4083         while ((unode = ulist_next(fs_info->qgroup_ulist, &uiter))) {
4084                 struct btrfs_qgroup *qg;
4085                 struct btrfs_qgroup_list *glist;
4086
4087                 qg = unode_aux_to_qgroup(unode);
4088
4089                 qgroup_rsv_release(fs_info, qg, num_bytes,
4090                                 BTRFS_QGROUP_RSV_META_PREALLOC);
4091                 qgroup_rsv_add(fs_info, qg, num_bytes,
4092                                 BTRFS_QGROUP_RSV_META_PERTRANS);
4093                 list_for_each_entry(glist, &qg->groups, next_group) {
4094                         ret = ulist_add(fs_info->qgroup_ulist,
4095                                         glist->group->qgroupid,
4096                                         qgroup_to_aux(glist->group), GFP_ATOMIC);
4097                         if (ret < 0)
4098                                 goto out;
4099                 }
4100         }
4101 out:
4102         spin_unlock(&fs_info->qgroup_lock);
4103 }
4104
4105 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes)
4106 {
4107         struct btrfs_fs_info *fs_info = root->fs_info;
4108
4109         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
4110             !is_fstree(root->root_key.objectid))
4111                 return;
4112         /* Same as btrfs_qgroup_free_meta_prealloc() */
4113         num_bytes = sub_root_meta_rsv(root, num_bytes,
4114                                       BTRFS_QGROUP_RSV_META_PREALLOC);
4115         trace_qgroup_meta_convert(root, num_bytes);
4116         qgroup_convert_meta(fs_info, root->root_key.objectid, num_bytes);
4117         if (!sb_rdonly(fs_info->sb))
4118                 add_root_meta_rsv(root, num_bytes, BTRFS_QGROUP_RSV_META_PERTRANS);
4119 }
4120
4121 /*
4122  * Check qgroup reserved space leaking, normally at destroy inode
4123  * time
4124  */
4125 void btrfs_qgroup_check_reserved_leak(struct btrfs_inode *inode)
4126 {
4127         struct extent_changeset changeset;
4128         struct ulist_node *unode;
4129         struct ulist_iterator iter;
4130         int ret;
4131
4132         extent_changeset_init(&changeset);
4133         ret = clear_record_extent_bits(&inode->io_tree, 0, (u64)-1,
4134                         EXTENT_QGROUP_RESERVED, &changeset);
4135
4136         WARN_ON(ret < 0);
4137         if (WARN_ON(changeset.bytes_changed)) {
4138                 ULIST_ITER_INIT(&iter);
4139                 while ((unode = ulist_next(&changeset.range_changed, &iter))) {
4140                         btrfs_warn(inode->root->fs_info,
4141                 "leaking qgroup reserved space, ino: %llu, start: %llu, end: %llu",
4142                                 btrfs_ino(inode), unode->val, unode->aux);
4143                 }
4144                 btrfs_qgroup_free_refroot(inode->root->fs_info,
4145                                 inode->root->root_key.objectid,
4146                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
4147
4148         }
4149         extent_changeset_release(&changeset);
4150 }
4151
4152 void btrfs_qgroup_init_swapped_blocks(
4153         struct btrfs_qgroup_swapped_blocks *swapped_blocks)
4154 {
4155         int i;
4156
4157         spin_lock_init(&swapped_blocks->lock);
4158         for (i = 0; i < BTRFS_MAX_LEVEL; i++)
4159                 swapped_blocks->blocks[i] = RB_ROOT;
4160         swapped_blocks->swapped = false;
4161 }
4162
4163 /*
4164  * Delete all swapped blocks record of @root.
4165  * Every record here means we skipped a full subtree scan for qgroup.
4166  *
4167  * Gets called when committing one transaction.
4168  */
4169 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root)
4170 {
4171         struct btrfs_qgroup_swapped_blocks *swapped_blocks;
4172         int i;
4173
4174         swapped_blocks = &root->swapped_blocks;
4175
4176         spin_lock(&swapped_blocks->lock);
4177         if (!swapped_blocks->swapped)
4178                 goto out;
4179         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
4180                 struct rb_root *cur_root = &swapped_blocks->blocks[i];
4181                 struct btrfs_qgroup_swapped_block *entry;
4182                 struct btrfs_qgroup_swapped_block *next;
4183
4184                 rbtree_postorder_for_each_entry_safe(entry, next, cur_root,
4185                                                      node)
4186                         kfree(entry);
4187                 swapped_blocks->blocks[i] = RB_ROOT;
4188         }
4189         swapped_blocks->swapped = false;
4190 out:
4191         spin_unlock(&swapped_blocks->lock);
4192 }
4193
4194 /*
4195  * Add subtree roots record into @subvol_root.
4196  *
4197  * @subvol_root:        tree root of the subvolume tree get swapped
4198  * @bg:                 block group under balance
4199  * @subvol_parent/slot: pointer to the subtree root in subvolume tree
4200  * @reloc_parent/slot:  pointer to the subtree root in reloc tree
4201  *                      BOTH POINTERS ARE BEFORE TREE SWAP
4202  * @last_snapshot:      last snapshot generation of the subvolume tree
4203  */
4204 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
4205                 struct btrfs_root *subvol_root,
4206                 struct btrfs_block_group *bg,
4207                 struct extent_buffer *subvol_parent, int subvol_slot,
4208                 struct extent_buffer *reloc_parent, int reloc_slot,
4209                 u64 last_snapshot)
4210 {
4211         struct btrfs_fs_info *fs_info = subvol_root->fs_info;
4212         struct btrfs_qgroup_swapped_blocks *blocks = &subvol_root->swapped_blocks;
4213         struct btrfs_qgroup_swapped_block *block;
4214         struct rb_node **cur;
4215         struct rb_node *parent = NULL;
4216         int level = btrfs_header_level(subvol_parent) - 1;
4217         int ret = 0;
4218
4219         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
4220                 return 0;
4221
4222         if (btrfs_node_ptr_generation(subvol_parent, subvol_slot) >
4223             btrfs_node_ptr_generation(reloc_parent, reloc_slot)) {
4224                 btrfs_err_rl(fs_info,
4225                 "%s: bad parameter order, subvol_gen=%llu reloc_gen=%llu",
4226                         __func__,
4227                         btrfs_node_ptr_generation(subvol_parent, subvol_slot),
4228                         btrfs_node_ptr_generation(reloc_parent, reloc_slot));
4229                 return -EUCLEAN;
4230         }
4231
4232         block = kmalloc(sizeof(*block), GFP_NOFS);
4233         if (!block) {
4234                 ret = -ENOMEM;
4235                 goto out;
4236         }
4237
4238         /*
4239          * @reloc_parent/slot is still before swap, while @block is going to
4240          * record the bytenr after swap, so we do the swap here.
4241          */
4242         block->subvol_bytenr = btrfs_node_blockptr(reloc_parent, reloc_slot);
4243         block->subvol_generation = btrfs_node_ptr_generation(reloc_parent,
4244                                                              reloc_slot);
4245         block->reloc_bytenr = btrfs_node_blockptr(subvol_parent, subvol_slot);
4246         block->reloc_generation = btrfs_node_ptr_generation(subvol_parent,
4247                                                             subvol_slot);
4248         block->last_snapshot = last_snapshot;
4249         block->level = level;
4250
4251         /*
4252          * If we have bg == NULL, we're called from btrfs_recover_relocation(),
4253          * no one else can modify tree blocks thus we qgroup will not change
4254          * no matter the value of trace_leaf.
4255          */
4256         if (bg && bg->flags & BTRFS_BLOCK_GROUP_DATA)
4257                 block->trace_leaf = true;
4258         else
4259                 block->trace_leaf = false;
4260         btrfs_node_key_to_cpu(reloc_parent, &block->first_key, reloc_slot);
4261
4262         /* Insert @block into @blocks */
4263         spin_lock(&blocks->lock);
4264         cur = &blocks->blocks[level].rb_node;
4265         while (*cur) {
4266                 struct btrfs_qgroup_swapped_block *entry;
4267
4268                 parent = *cur;
4269                 entry = rb_entry(parent, struct btrfs_qgroup_swapped_block,
4270                                  node);
4271
4272                 if (entry->subvol_bytenr < block->subvol_bytenr) {
4273                         cur = &(*cur)->rb_left;
4274                 } else if (entry->subvol_bytenr > block->subvol_bytenr) {
4275                         cur = &(*cur)->rb_right;
4276                 } else {
4277                         if (entry->subvol_generation !=
4278                                         block->subvol_generation ||
4279                             entry->reloc_bytenr != block->reloc_bytenr ||
4280                             entry->reloc_generation !=
4281                                         block->reloc_generation) {
4282                                 /*
4283                                  * Duplicated but mismatch entry found.
4284                                  * Shouldn't happen.
4285                                  *
4286                                  * Marking qgroup inconsistent should be enough
4287                                  * for end users.
4288                                  */
4289                                 WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
4290                                 ret = -EEXIST;
4291                         }
4292                         kfree(block);
4293                         goto out_unlock;
4294                 }
4295         }
4296         rb_link_node(&block->node, parent, cur);
4297         rb_insert_color(&block->node, &blocks->blocks[level]);
4298         blocks->swapped = true;
4299 out_unlock:
4300         spin_unlock(&blocks->lock);
4301 out:
4302         if (ret < 0)
4303                 fs_info->qgroup_flags |=
4304                         BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
4305         return ret;
4306 }
4307
4308 /*
4309  * Check if the tree block is a subtree root, and if so do the needed
4310  * delayed subtree trace for qgroup.
4311  *
4312  * This is called during btrfs_cow_block().
4313  */
4314 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
4315                                          struct btrfs_root *root,
4316                                          struct extent_buffer *subvol_eb)
4317 {
4318         struct btrfs_fs_info *fs_info = root->fs_info;
4319         struct btrfs_qgroup_swapped_blocks *blocks = &root->swapped_blocks;
4320         struct btrfs_qgroup_swapped_block *block;
4321         struct extent_buffer *reloc_eb = NULL;
4322         struct rb_node *node;
4323         bool found = false;
4324         bool swapped = false;
4325         int level = btrfs_header_level(subvol_eb);
4326         int ret = 0;
4327         int i;
4328
4329         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
4330                 return 0;
4331         if (!is_fstree(root->root_key.objectid) || !root->reloc_root)
4332                 return 0;
4333
4334         spin_lock(&blocks->lock);
4335         if (!blocks->swapped) {
4336                 spin_unlock(&blocks->lock);
4337                 return 0;
4338         }
4339         node = blocks->blocks[level].rb_node;
4340
4341         while (node) {
4342                 block = rb_entry(node, struct btrfs_qgroup_swapped_block, node);
4343                 if (block->subvol_bytenr < subvol_eb->start) {
4344                         node = node->rb_left;
4345                 } else if (block->subvol_bytenr > subvol_eb->start) {
4346                         node = node->rb_right;
4347                 } else {
4348                         found = true;
4349                         break;
4350                 }
4351         }
4352         if (!found) {
4353                 spin_unlock(&blocks->lock);
4354                 goto out;
4355         }
4356         /* Found one, remove it from @blocks first and update blocks->swapped */
4357         rb_erase(&block->node, &blocks->blocks[level]);
4358         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
4359                 if (RB_EMPTY_ROOT(&blocks->blocks[i])) {
4360                         swapped = true;
4361                         break;
4362                 }
4363         }
4364         blocks->swapped = swapped;
4365         spin_unlock(&blocks->lock);
4366
4367         /* Read out reloc subtree root */
4368         reloc_eb = read_tree_block(fs_info, block->reloc_bytenr,
4369                                    block->reloc_generation, block->level,
4370                                    &block->first_key);
4371         if (IS_ERR(reloc_eb)) {
4372                 ret = PTR_ERR(reloc_eb);
4373                 reloc_eb = NULL;
4374                 goto free_out;
4375         }
4376         if (!extent_buffer_uptodate(reloc_eb)) {
4377                 ret = -EIO;
4378                 goto free_out;
4379         }
4380
4381         ret = qgroup_trace_subtree_swap(trans, reloc_eb, subvol_eb,
4382                         block->last_snapshot, block->trace_leaf);
4383 free_out:
4384         kfree(block);
4385         free_extent_buffer(reloc_eb);
4386 out:
4387         if (ret < 0) {
4388                 btrfs_err_rl(fs_info,
4389                              "failed to account subtree at bytenr %llu: %d",
4390                              subvol_eb->start, ret);
4391                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
4392         }
4393         return ret;
4394 }
4395
4396 void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans)
4397 {
4398         struct btrfs_qgroup_extent_record *entry;
4399         struct btrfs_qgroup_extent_record *next;
4400         struct rb_root *root;
4401
4402         root = &trans->delayed_refs.dirty_extent_root;
4403         rbtree_postorder_for_each_entry_safe(entry, next, root, node) {
4404                 ulist_free(entry->old_roots);
4405                 kfree(entry);
4406         }
4407         *root = RB_ROOT;
4408 }