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 #include "tree-mod-log.h"
  27 #include "fs.h"
  28 #include "accessors.h"
  29 #include "extent-tree.h"
  30 #include "root-tree.h"
  31 #include "tree-checker.h"
  32
  33 enum btrfs_qgroup_mode btrfs_qgroup_mode(struct btrfs_fs_info *fs_info)
  34 {
  35         if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
  36                 return BTRFS_QGROUP_MODE_DISABLED;
  37         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE)
  38                 return BTRFS_QGROUP_MODE_SIMPLE;
  39         return BTRFS_QGROUP_MODE_FULL;
  40 }
  41
  42 bool btrfs_qgroup_enabled(struct btrfs_fs_info *fs_info)
  43 {
  44         return btrfs_qgroup_mode(fs_info) != BTRFS_QGROUP_MODE_DISABLED;
  45 }
  46
  47 bool btrfs_qgroup_full_accounting(struct btrfs_fs_info *fs_info)
  48 {
  49         return btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL;
  50 }
  51
  52 /*
  53  * Helpers to access qgroup reservation
  54  *
  55  * Callers should ensure the lock context and type are valid
  56  */
  57
  58 static u64 qgroup_rsv_total(const struct btrfs_qgroup *qgroup)
  59 {
  60         u64 ret = 0;
  61         int i;
  62
  63         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
  64                 ret += qgroup->rsv.values[i];
  65
  66         return ret;
  67 }
  68
  69 #ifdef CONFIG_BTRFS_DEBUG
  70 static const char *qgroup_rsv_type_str(enum btrfs_qgroup_rsv_type type)
  71 {
  72         if (type == BTRFS_QGROUP_RSV_DATA)
  73                 return "data";
  74         if (type == BTRFS_QGROUP_RSV_META_PERTRANS)
  75                 return "meta_pertrans";
  76         if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
  77                 return "meta_prealloc";
  78         return NULL;
  79 }
  80 #endif
  81
  82 static void qgroup_rsv_add(struct btrfs_fs_info *fs_info,
  83                            struct btrfs_qgroup *qgroup, u64 num_bytes,
  84                            enum btrfs_qgroup_rsv_type type)
  85 {
  86         trace_qgroup_update_reserve(fs_info, qgroup, num_bytes, type);
  87         qgroup->rsv.values[type] += num_bytes;
  88 }
  89
  90 static void qgroup_rsv_release(struct btrfs_fs_info *fs_info,
  91                                struct btrfs_qgroup *qgroup, u64 num_bytes,
  92                                enum btrfs_qgroup_rsv_type type)
  93 {
  94         trace_qgroup_update_reserve(fs_info, qgroup, -(s64)num_bytes, type);
  95         if (qgroup->rsv.values[type] >= num_bytes) {
  96                 qgroup->rsv.values[type] -= num_bytes;
  97                 return;
  98         }
  99 #ifdef CONFIG_BTRFS_DEBUG
 100         WARN_RATELIMIT(1,
 101                 "qgroup %llu %s reserved space underflow, have %llu to free %llu",
 102                 qgroup->qgroupid, qgroup_rsv_type_str(type),
 103                 qgroup->rsv.values[type], num_bytes);
 104 #endif
 105         qgroup->rsv.values[type] = 0;
 106 }
 107
 108 static void qgroup_rsv_add_by_qgroup(struct btrfs_fs_info *fs_info,
 109                                      struct btrfs_qgroup *dest,
 110                                      struct btrfs_qgroup *src)
 111 {
 112         int i;
 113
 114         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
 115                 qgroup_rsv_add(fs_info, dest, src->rsv.values[i], i);
 116 }
 117
 118 static void qgroup_rsv_release_by_qgroup(struct btrfs_fs_info *fs_info,
 119                                          struct btrfs_qgroup *dest,
 120                                           struct btrfs_qgroup *src)
 121 {
 122         int i;
 123
 124         for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++)
 125                 qgroup_rsv_release(fs_info, dest, src->rsv.values[i], i);
 126 }
 127
 128 static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,
 129                                            int mod)
 130 {
 131         if (qg->old_refcnt < seq)
 132                 qg->old_refcnt = seq;
 133         qg->old_refcnt += mod;
 134 }
 135
 136 static void btrfs_qgroup_update_new_refcnt(struct btrfs_qgroup *qg, u64 seq,
 137                                            int mod)
 138 {
 139         if (qg->new_refcnt < seq)
 140                 qg->new_refcnt = seq;
 141         qg->new_refcnt += mod;
 142 }
 143
 144 static inline u64 btrfs_qgroup_get_old_refcnt(struct btrfs_qgroup *qg, u64 seq)
 145 {
 146         if (qg->old_refcnt < seq)
 147                 return 0;
 148         return qg->old_refcnt - seq;
 149 }
 150
 151 static inline u64 btrfs_qgroup_get_new_refcnt(struct btrfs_qgroup *qg, u64 seq)
 152 {
 153         if (qg->new_refcnt < seq)
 154                 return 0;
 155         return qg->new_refcnt - seq;
 156 }
 157
 158 /*
 159  * glue structure to represent the relations between qgroups.
 160  */
 161 struct btrfs_qgroup_list {
 162         struct list_head next_group;
 163         struct list_head next_member;
 164         struct btrfs_qgroup *group;
 165         struct btrfs_qgroup *member;
 166 };
 167
 168 static int
 169 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
 170                    int init_flags);
 171 static void qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info);
 172
 173 /* must be called with qgroup_ioctl_lock held */
 174 static struct btrfs_qgroup *find_qgroup_rb(struct btrfs_fs_info *fs_info,
 175                                            u64 qgroupid)
 176 {
 177         struct rb_node *n = fs_info->qgroup_tree.rb_node;
 178         struct btrfs_qgroup *qgroup;
 179
 180         while (n) {
 181                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
 182                 if (qgroup->qgroupid < qgroupid)
 183                         n = n->rb_left;
 184                 else if (qgroup->qgroupid > qgroupid)
 185                         n = n->rb_right;
 186                 else
 187                         return qgroup;
 188         }
 189         return NULL;
 190 }
 191
 192 /*
 193  * Add qgroup to the filesystem's qgroup tree.
 194  *
 195  * Must be called with qgroup_lock held and @prealloc preallocated.
 196  *
 197  * The control on the lifespan of @prealloc would be transferred to this
 198  * function, thus caller should no longer touch @prealloc.
 199  */
 200 static struct btrfs_qgroup *add_qgroup_rb(struct btrfs_fs_info *fs_info,
 201                                           struct btrfs_qgroup *prealloc,
 202                                           u64 qgroupid)
 203 {
 204         struct rb_node **p = &fs_info->qgroup_tree.rb_node;
 205         struct rb_node *parent = NULL;
 206         struct btrfs_qgroup *qgroup;
 207
 208         /* Caller must have pre-allocated @prealloc. */
 209         ASSERT(prealloc);
 210
 211         while (*p) {
 212                 parent = *p;
 213                 qgroup = rb_entry(parent, struct btrfs_qgroup, node);
 214
 215                 if (qgroup->qgroupid < qgroupid) {
 216                         p = &(*p)->rb_left;
 217                 } else if (qgroup->qgroupid > qgroupid) {
 218                         p = &(*p)->rb_right;
 219                 } else {
 220                         kfree(prealloc);
 221                         return qgroup;
 222                 }
 223         }
 224
 225         qgroup = prealloc;
 226         qgroup->qgroupid = qgroupid;
 227         INIT_LIST_HEAD(&qgroup->groups);
 228         INIT_LIST_HEAD(&qgroup->members);
 229         INIT_LIST_HEAD(&qgroup->dirty);
 230         INIT_LIST_HEAD(&qgroup->iterator);
 231         INIT_LIST_HEAD(&qgroup->nested_iterator);
 232
 233         rb_link_node(&qgroup->node, parent, p);
 234         rb_insert_color(&qgroup->node, &fs_info->qgroup_tree);
 235
 236         return qgroup;
 237 }
 238
 239 static void __del_qgroup_rb(struct btrfs_fs_info *fs_info,
 240                             struct btrfs_qgroup *qgroup)
 241 {
 242         struct btrfs_qgroup_list *list;
 243
 244         list_del(&qgroup->dirty);
 245         while (!list_empty(&qgroup->groups)) {
 246                 list = list_first_entry(&qgroup->groups,
 247                                         struct btrfs_qgroup_list, next_group);
 248                 list_del(&list->next_group);
 249                 list_del(&list->next_member);
 250                 kfree(list);
 251         }
 252
 253         while (!list_empty(&qgroup->members)) {
 254                 list = list_first_entry(&qgroup->members,
 255                                         struct btrfs_qgroup_list, next_member);
 256                 list_del(&list->next_group);
 257                 list_del(&list->next_member);
 258                 kfree(list);
 259         }
 260 }
 261
 262 /* must be called with qgroup_lock held */
 263 static int del_qgroup_rb(struct btrfs_fs_info *fs_info, u64 qgroupid)
 264 {
 265         struct btrfs_qgroup *qgroup = find_qgroup_rb(fs_info, qgroupid);
 266
 267         if (!qgroup)
 268                 return -ENOENT;
 269
 270         rb_erase(&qgroup->node, &fs_info->qgroup_tree);
 271         __del_qgroup_rb(fs_info, qgroup);
 272         return 0;
 273 }
 274
 275 /*
 276  * Add relation specified by two qgroups.
 277  *
 278  * Must be called with qgroup_lock held, the ownership of @prealloc is
 279  * transferred to this function and caller should not touch it anymore.
 280  *
 281  * Return: 0        on success
 282  *         -ENOENT  if one of the qgroups is NULL
 283  *         <0       other errors
 284  */
 285 static int __add_relation_rb(struct btrfs_qgroup_list *prealloc,
 286                              struct btrfs_qgroup *member,
 287                              struct btrfs_qgroup *parent)
 288 {
 289         if (!member || !parent) {
 290                 kfree(prealloc);
 291                 return -ENOENT;
 292         }
 293
 294         prealloc->group = parent;
 295         prealloc->member = member;
 296         list_add_tail(&prealloc->next_group, &member->groups);
 297         list_add_tail(&prealloc->next_member, &parent->members);
 298
 299         return 0;
 300 }
 301
 302 /*
 303  * Add relation specified by two qgroup ids.
 304  *
 305  * Must be called with qgroup_lock held.
 306  *
 307  * Return: 0        on success
 308  *         -ENOENT  if one of the ids does not exist
 309  *         <0       other errors
 310  */
 311 static int add_relation_rb(struct btrfs_fs_info *fs_info,
 312                            struct btrfs_qgroup_list *prealloc,
 313                            u64 memberid, u64 parentid)
 314 {
 315         struct btrfs_qgroup *member;
 316         struct btrfs_qgroup *parent;
 317
 318         member = find_qgroup_rb(fs_info, memberid);
 319         parent = find_qgroup_rb(fs_info, parentid);
 320
 321         return __add_relation_rb(prealloc, member, parent);
 322 }
 323
 324 /* Must be called with qgroup_lock held */
 325 static int del_relation_rb(struct btrfs_fs_info *fs_info,
 326                            u64 memberid, u64 parentid)
 327 {
 328         struct btrfs_qgroup *member;
 329         struct btrfs_qgroup *parent;
 330         struct btrfs_qgroup_list *list;
 331
 332         member = find_qgroup_rb(fs_info, memberid);
 333         parent = find_qgroup_rb(fs_info, parentid);
 334         if (!member || !parent)
 335                 return -ENOENT;
 336
 337         list_for_each_entry(list, &member->groups, next_group) {
 338                 if (list->group == parent) {
 339                         list_del(&list->next_group);
 340                         list_del(&list->next_member);
 341                         kfree(list);
 342                         return 0;
 343                 }
 344         }
 345         return -ENOENT;
 346 }
 347
 348 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
 349 int btrfs_verify_qgroup_counts(struct btrfs_fs_info *fs_info, u64 qgroupid,
 350                                u64 rfer, u64 excl)
 351 {
 352         struct btrfs_qgroup *qgroup;
 353
 354         qgroup = find_qgroup_rb(fs_info, qgroupid);
 355         if (!qgroup)
 356                 return -EINVAL;
 357         if (qgroup->rfer != rfer || qgroup->excl != excl)
 358                 return -EINVAL;
 359         return 0;
 360 }
 361 #endif
 362
 363 static void qgroup_mark_inconsistent(struct btrfs_fs_info *fs_info)
 364 {
 365         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
 366                 return;
 367         fs_info->qgroup_flags |= (BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT |
 368                                   BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN |
 369                                   BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING);
 370 }
 371
 372 static void qgroup_read_enable_gen(struct btrfs_fs_info *fs_info,
 373                                    struct extent_buffer *leaf, int slot,
 374                                    struct btrfs_qgroup_status_item *ptr)
 375 {
 376         ASSERT(btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
 377         ASSERT(btrfs_item_size(leaf, slot) >= sizeof(*ptr));
 378         fs_info->qgroup_enable_gen = btrfs_qgroup_status_enable_gen(leaf, ptr);
 379 }
 380
 381 /*
 382  * The full config is read in one go, only called from open_ctree()
 383  * It doesn't use any locking, as at this point we're still single-threaded
 384  */
 385 int btrfs_read_qgroup_config(struct btrfs_fs_info *fs_info)
 386 {
 387         struct btrfs_key key;
 388         struct btrfs_key found_key;
 389         struct btrfs_root *quota_root = fs_info->quota_root;
 390         struct btrfs_path *path = NULL;
 391         struct extent_buffer *l;
 392         int slot;
 393         int ret = 0;
 394         u64 flags = 0;
 395         u64 rescan_progress = 0;
 396
 397         if (!fs_info->quota_root)
 398                 return 0;
 399
 400         fs_info->qgroup_ulist = ulist_alloc(GFP_KERNEL);
 401         if (!fs_info->qgroup_ulist) {
 402                 ret = -ENOMEM;
 403                 goto out;
 404         }
 405
 406         path = btrfs_alloc_path();
 407         if (!path) {
 408                 ret = -ENOMEM;
 409                 goto out;
 410         }
 411
 412         ret = btrfs_sysfs_add_qgroups(fs_info);
 413         if (ret < 0)
 414                 goto out;
 415         /* default this to quota off, in case no status key is found */
 416         fs_info->qgroup_flags = 0;
 417
 418         /*
 419          * pass 1: read status, all qgroup infos and limits
 420          */
 421         key.objectid = 0;
 422         key.type = 0;
 423         key.offset = 0;
 424         ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 1);
 425         if (ret)
 426                 goto out;
 427
 428         while (1) {
 429                 struct btrfs_qgroup *qgroup;
 430
 431                 slot = path->slots[0];
 432                 l = path->nodes[0];
 433                 btrfs_item_key_to_cpu(l, &found_key, slot);
 434
 435                 if (found_key.type == BTRFS_QGROUP_STATUS_KEY) {
 436                         struct btrfs_qgroup_status_item *ptr;
 437
 438                         ptr = btrfs_item_ptr(l, slot,
 439                                              struct btrfs_qgroup_status_item);
 440
 441                         if (btrfs_qgroup_status_version(l, ptr) !=
 442                             BTRFS_QGROUP_STATUS_VERSION) {
 443                                 btrfs_err(fs_info,
 444                                  "old qgroup version, quota disabled");
 445                                 goto out;
 446                         }
 447                         fs_info->qgroup_flags = btrfs_qgroup_status_flags(l, ptr);
 448                         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE) {
 449                                 qgroup_read_enable_gen(fs_info, l, slot, ptr);
 450                         } else if (btrfs_qgroup_status_generation(l, ptr) != fs_info->generation) {
 451                                 qgroup_mark_inconsistent(fs_info);
 452                                 btrfs_err(fs_info,
 453                                         "qgroup generation mismatch, marked as inconsistent");
 454                         }
 455                         rescan_progress = btrfs_qgroup_status_rescan(l, ptr);
 456                         goto next1;
 457                 }
 458
 459                 if (found_key.type != BTRFS_QGROUP_INFO_KEY &&
 460                     found_key.type != BTRFS_QGROUP_LIMIT_KEY)
 461                         goto next1;
 462
 463                 qgroup = find_qgroup_rb(fs_info, found_key.offset);
 464                 if ((qgroup && found_key.type == BTRFS_QGROUP_INFO_KEY) ||
 465                     (!qgroup && found_key.type == BTRFS_QGROUP_LIMIT_KEY)) {
 466                         btrfs_err(fs_info, "inconsistent qgroup config");
 467                         qgroup_mark_inconsistent(fs_info);
 468                 }
 469                 if (!qgroup) {
 470                         struct btrfs_qgroup *prealloc;
 471
 472                         prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
 473                         if (!prealloc) {
 474                                 ret = -ENOMEM;
 475                                 goto out;
 476                         }
 477                         qgroup = add_qgroup_rb(fs_info, prealloc, found_key.offset);
 478                 }
 479                 ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
 480                 if (ret < 0)
 481                         goto out;
 482
 483                 switch (found_key.type) {
 484                 case BTRFS_QGROUP_INFO_KEY: {
 485                         struct btrfs_qgroup_info_item *ptr;
 486
 487                         ptr = btrfs_item_ptr(l, slot,
 488                                              struct btrfs_qgroup_info_item);
 489                         qgroup->rfer = btrfs_qgroup_info_rfer(l, ptr);
 490                         qgroup->rfer_cmpr = btrfs_qgroup_info_rfer_cmpr(l, ptr);
 491                         qgroup->excl = btrfs_qgroup_info_excl(l, ptr);
 492                         qgroup->excl_cmpr = btrfs_qgroup_info_excl_cmpr(l, ptr);
 493                         /* generation currently unused */
 494                         break;
 495                 }
 496                 case BTRFS_QGROUP_LIMIT_KEY: {
 497                         struct btrfs_qgroup_limit_item *ptr;
 498
 499                         ptr = btrfs_item_ptr(l, slot,
 500                                              struct btrfs_qgroup_limit_item);
 501                         qgroup->lim_flags = btrfs_qgroup_limit_flags(l, ptr);
 502                         qgroup->max_rfer = btrfs_qgroup_limit_max_rfer(l, ptr);
 503                         qgroup->max_excl = btrfs_qgroup_limit_max_excl(l, ptr);
 504                         qgroup->rsv_rfer = btrfs_qgroup_limit_rsv_rfer(l, ptr);
 505                         qgroup->rsv_excl = btrfs_qgroup_limit_rsv_excl(l, ptr);
 506                         break;
 507                 }
 508                 }
 509 next1:
 510                 ret = btrfs_next_item(quota_root, path);
 511                 if (ret < 0)
 512                         goto out;
 513                 if (ret)
 514                         break;
 515         }
 516         btrfs_release_path(path);
 517
 518         /*
 519          * pass 2: read all qgroup relations
 520          */
 521         key.objectid = 0;
 522         key.type = BTRFS_QGROUP_RELATION_KEY;
 523         key.offset = 0;
 524         ret = btrfs_search_slot_for_read(quota_root, &key, path, 1, 0);
 525         if (ret)
 526                 goto out;
 527         while (1) {
 528                 struct btrfs_qgroup_list *list = NULL;
 529
 530                 slot = path->slots[0];
 531                 l = path->nodes[0];
 532                 btrfs_item_key_to_cpu(l, &found_key, slot);
 533
 534                 if (found_key.type != BTRFS_QGROUP_RELATION_KEY)
 535                         goto next2;
 536
 537                 if (found_key.objectid > found_key.offset) {
 538                         /* parent <- member, not needed to build config */
 539                         /* FIXME should we omit the key completely? */
 540                         goto next2;
 541                 }
 542
 543                 list = kzalloc(sizeof(*list), GFP_KERNEL);
 544                 if (!list) {
 545                         ret = -ENOMEM;
 546                         goto out;
 547                 }
 548                 ret = add_relation_rb(fs_info, list, found_key.objectid,
 549                                       found_key.offset);
 550                 list = NULL;
 551                 if (ret == -ENOENT) {
 552                         btrfs_warn(fs_info,
 553                                 "orphan qgroup relation 0x%llx->0x%llx",
 554                                 found_key.objectid, found_key.offset);
 555                         ret = 0;        /* ignore the error */
 556                 }
 557                 if (ret)
 558                         goto out;
 559 next2:
 560                 ret = btrfs_next_item(quota_root, path);
 561                 if (ret < 0)
 562                         goto out;
 563                 if (ret)
 564                         break;
 565         }
 566 out:
 567         btrfs_free_path(path);
 568         fs_info->qgroup_flags |= flags;
 569         if (ret >= 0) {
 570                 if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_ON)
 571                         set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
 572                 if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN)
 573                         ret = qgroup_rescan_init(fs_info, rescan_progress, 0);
 574         } else {
 575                 ulist_free(fs_info->qgroup_ulist);
 576                 fs_info->qgroup_ulist = NULL;
 577                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
 578                 btrfs_sysfs_del_qgroups(fs_info);
 579         }
 580
 581         return ret < 0 ? ret : 0;
 582 }
 583
 584 /*
 585  * Called in close_ctree() when quota is still enabled.  This verifies we don't
 586  * leak some reserved space.
 587  *
 588  * Return false if no reserved space is left.
 589  * Return true if some reserved space is leaked.
 590  */
 591 bool btrfs_check_quota_leak(struct btrfs_fs_info *fs_info)
 592 {
 593         struct rb_node *node;
 594         bool ret = false;
 595
 596         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED)
 597                 return ret;
 598         /*
 599          * Since we're unmounting, there is no race and no need to grab qgroup
 600          * lock.  And here we don't go post-order to provide a more user
 601          * friendly sorted result.
 602          */
 603         for (node = rb_first(&fs_info->qgroup_tree); node; node = rb_next(node)) {
 604                 struct btrfs_qgroup *qgroup;
 605                 int i;
 606
 607                 qgroup = rb_entry(node, struct btrfs_qgroup, node);
 608                 for (i = 0; i < BTRFS_QGROUP_RSV_LAST; i++) {
 609                         if (qgroup->rsv.values[i]) {
 610                                 ret = true;
 611                                 btrfs_warn(fs_info,
 612                 "qgroup %hu/%llu has unreleased space, type %d rsv %llu",
 613                                    btrfs_qgroup_level(qgroup->qgroupid),
 614                                    btrfs_qgroup_subvolid(qgroup->qgroupid),
 615                                    i, qgroup->rsv.values[i]);
 616                         }
 617                 }
 618         }
 619         return ret;
 620 }
 621
 622 /*
 623  * This is called from close_ctree() or open_ctree() or btrfs_quota_disable(),
 624  * first two are in single-threaded paths.And for the third one, we have set
 625  * quota_root to be null with qgroup_lock held before, so it is safe to clean
 626  * up the in-memory structures without qgroup_lock held.
 627  */
 628 void btrfs_free_qgroup_config(struct btrfs_fs_info *fs_info)
 629 {
 630         struct rb_node *n;
 631         struct btrfs_qgroup *qgroup;
 632
 633         while ((n = rb_first(&fs_info->qgroup_tree))) {
 634                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
 635                 rb_erase(n, &fs_info->qgroup_tree);
 636                 __del_qgroup_rb(fs_info, qgroup);
 637                 btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
 638                 kfree(qgroup);
 639         }
 640         /*
 641          * We call btrfs_free_qgroup_config() when unmounting
 642          * filesystem and disabling quota, so we set qgroup_ulist
 643          * to be null here to avoid double free.
 644          */
 645         ulist_free(fs_info->qgroup_ulist);
 646         fs_info->qgroup_ulist = NULL;
 647         btrfs_sysfs_del_qgroups(fs_info);
 648 }
 649
 650 static int add_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
 651                                     u64 dst)
 652 {
 653         int ret;
 654         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 655         struct btrfs_path *path;
 656         struct btrfs_key key;
 657
 658         path = btrfs_alloc_path();
 659         if (!path)
 660                 return -ENOMEM;
 661
 662         key.objectid = src;
 663         key.type = BTRFS_QGROUP_RELATION_KEY;
 664         key.offset = dst;
 665
 666         ret = btrfs_insert_empty_item(trans, quota_root, path, &key, 0);
 667
 668         btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 669
 670         btrfs_free_path(path);
 671         return ret;
 672 }
 673
 674 static int del_qgroup_relation_item(struct btrfs_trans_handle *trans, u64 src,
 675                                     u64 dst)
 676 {
 677         int ret;
 678         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 679         struct btrfs_path *path;
 680         struct btrfs_key key;
 681
 682         path = btrfs_alloc_path();
 683         if (!path)
 684                 return -ENOMEM;
 685
 686         key.objectid = src;
 687         key.type = BTRFS_QGROUP_RELATION_KEY;
 688         key.offset = dst;
 689
 690         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
 691         if (ret < 0)
 692                 goto out;
 693
 694         if (ret > 0) {
 695                 ret = -ENOENT;
 696                 goto out;
 697         }
 698
 699         ret = btrfs_del_item(trans, quota_root, path);
 700 out:
 701         btrfs_free_path(path);
 702         return ret;
 703 }
 704
 705 static int add_qgroup_item(struct btrfs_trans_handle *trans,
 706                            struct btrfs_root *quota_root, u64 qgroupid)
 707 {
 708         int ret;
 709         struct btrfs_path *path;
 710         struct btrfs_qgroup_info_item *qgroup_info;
 711         struct btrfs_qgroup_limit_item *qgroup_limit;
 712         struct extent_buffer *leaf;
 713         struct btrfs_key key;
 714
 715         if (btrfs_is_testing(quota_root->fs_info))
 716                 return 0;
 717
 718         path = btrfs_alloc_path();
 719         if (!path)
 720                 return -ENOMEM;
 721
 722         key.objectid = 0;
 723         key.type = BTRFS_QGROUP_INFO_KEY;
 724         key.offset = qgroupid;
 725
 726         /*
 727          * Avoid a transaction abort by catching -EEXIST here. In that
 728          * case, we proceed by re-initializing the existing structure
 729          * on disk.
 730          */
 731
 732         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
 733                                       sizeof(*qgroup_info));
 734         if (ret && ret != -EEXIST)
 735                 goto out;
 736
 737         leaf = path->nodes[0];
 738         qgroup_info = btrfs_item_ptr(leaf, path->slots[0],
 739                                  struct btrfs_qgroup_info_item);
 740         btrfs_set_qgroup_info_generation(leaf, qgroup_info, trans->transid);
 741         btrfs_set_qgroup_info_rfer(leaf, qgroup_info, 0);
 742         btrfs_set_qgroup_info_rfer_cmpr(leaf, qgroup_info, 0);
 743         btrfs_set_qgroup_info_excl(leaf, qgroup_info, 0);
 744         btrfs_set_qgroup_info_excl_cmpr(leaf, qgroup_info, 0);
 745
 746         btrfs_mark_buffer_dirty(trans, leaf);
 747
 748         btrfs_release_path(path);
 749
 750         key.type = BTRFS_QGROUP_LIMIT_KEY;
 751         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
 752                                       sizeof(*qgroup_limit));
 753         if (ret && ret != -EEXIST)
 754                 goto out;
 755
 756         leaf = path->nodes[0];
 757         qgroup_limit = btrfs_item_ptr(leaf, path->slots[0],
 758                                   struct btrfs_qgroup_limit_item);
 759         btrfs_set_qgroup_limit_flags(leaf, qgroup_limit, 0);
 760         btrfs_set_qgroup_limit_max_rfer(leaf, qgroup_limit, 0);
 761         btrfs_set_qgroup_limit_max_excl(leaf, qgroup_limit, 0);
 762         btrfs_set_qgroup_limit_rsv_rfer(leaf, qgroup_limit, 0);
 763         btrfs_set_qgroup_limit_rsv_excl(leaf, qgroup_limit, 0);
 764
 765         btrfs_mark_buffer_dirty(trans, leaf);
 766
 767         ret = 0;
 768 out:
 769         btrfs_free_path(path);
 770         return ret;
 771 }
 772
 773 static int del_qgroup_item(struct btrfs_trans_handle *trans, u64 qgroupid)
 774 {
 775         int ret;
 776         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 777         struct btrfs_path *path;
 778         struct btrfs_key key;
 779
 780         path = btrfs_alloc_path();
 781         if (!path)
 782                 return -ENOMEM;
 783
 784         key.objectid = 0;
 785         key.type = BTRFS_QGROUP_INFO_KEY;
 786         key.offset = qgroupid;
 787         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
 788         if (ret < 0)
 789                 goto out;
 790
 791         if (ret > 0) {
 792                 ret = -ENOENT;
 793                 goto out;
 794         }
 795
 796         ret = btrfs_del_item(trans, quota_root, path);
 797         if (ret)
 798                 goto out;
 799
 800         btrfs_release_path(path);
 801
 802         key.type = BTRFS_QGROUP_LIMIT_KEY;
 803         ret = btrfs_search_slot(trans, quota_root, &key, path, -1, 1);
 804         if (ret < 0)
 805                 goto out;
 806
 807         if (ret > 0) {
 808                 ret = -ENOENT;
 809                 goto out;
 810         }
 811
 812         ret = btrfs_del_item(trans, quota_root, path);
 813
 814 out:
 815         btrfs_free_path(path);
 816         return ret;
 817 }
 818
 819 static int update_qgroup_limit_item(struct btrfs_trans_handle *trans,
 820                                     struct btrfs_qgroup *qgroup)
 821 {
 822         struct btrfs_root *quota_root = trans->fs_info->quota_root;
 823         struct btrfs_path *path;
 824         struct btrfs_key key;
 825         struct extent_buffer *l;
 826         struct btrfs_qgroup_limit_item *qgroup_limit;
 827         int ret;
 828         int slot;
 829
 830         key.objectid = 0;
 831         key.type = BTRFS_QGROUP_LIMIT_KEY;
 832         key.offset = qgroup->qgroupid;
 833
 834         path = btrfs_alloc_path();
 835         if (!path)
 836                 return -ENOMEM;
 837
 838         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
 839         if (ret > 0)
 840                 ret = -ENOENT;
 841
 842         if (ret)
 843                 goto out;
 844
 845         l = path->nodes[0];
 846         slot = path->slots[0];
 847         qgroup_limit = btrfs_item_ptr(l, slot, struct btrfs_qgroup_limit_item);
 848         btrfs_set_qgroup_limit_flags(l, qgroup_limit, qgroup->lim_flags);
 849         btrfs_set_qgroup_limit_max_rfer(l, qgroup_limit, qgroup->max_rfer);
 850         btrfs_set_qgroup_limit_max_excl(l, qgroup_limit, qgroup->max_excl);
 851         btrfs_set_qgroup_limit_rsv_rfer(l, qgroup_limit, qgroup->rsv_rfer);
 852         btrfs_set_qgroup_limit_rsv_excl(l, qgroup_limit, qgroup->rsv_excl);
 853
 854         btrfs_mark_buffer_dirty(trans, l);
 855
 856 out:
 857         btrfs_free_path(path);
 858         return ret;
 859 }
 860
 861 static int update_qgroup_info_item(struct btrfs_trans_handle *trans,
 862                                    struct btrfs_qgroup *qgroup)
 863 {
 864         struct btrfs_fs_info *fs_info = trans->fs_info;
 865         struct btrfs_root *quota_root = fs_info->quota_root;
 866         struct btrfs_path *path;
 867         struct btrfs_key key;
 868         struct extent_buffer *l;
 869         struct btrfs_qgroup_info_item *qgroup_info;
 870         int ret;
 871         int slot;
 872
 873         if (btrfs_is_testing(fs_info))
 874                 return 0;
 875
 876         key.objectid = 0;
 877         key.type = BTRFS_QGROUP_INFO_KEY;
 878         key.offset = qgroup->qgroupid;
 879
 880         path = btrfs_alloc_path();
 881         if (!path)
 882                 return -ENOMEM;
 883
 884         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
 885         if (ret > 0)
 886                 ret = -ENOENT;
 887
 888         if (ret)
 889                 goto out;
 890
 891         l = path->nodes[0];
 892         slot = path->slots[0];
 893         qgroup_info = btrfs_item_ptr(l, slot, struct btrfs_qgroup_info_item);
 894         btrfs_set_qgroup_info_generation(l, qgroup_info, trans->transid);
 895         btrfs_set_qgroup_info_rfer(l, qgroup_info, qgroup->rfer);
 896         btrfs_set_qgroup_info_rfer_cmpr(l, qgroup_info, qgroup->rfer_cmpr);
 897         btrfs_set_qgroup_info_excl(l, qgroup_info, qgroup->excl);
 898         btrfs_set_qgroup_info_excl_cmpr(l, qgroup_info, qgroup->excl_cmpr);
 899
 900         btrfs_mark_buffer_dirty(trans, l);
 901
 902 out:
 903         btrfs_free_path(path);
 904         return ret;
 905 }
 906
 907 static int update_qgroup_status_item(struct btrfs_trans_handle *trans)
 908 {
 909         struct btrfs_fs_info *fs_info = trans->fs_info;
 910         struct btrfs_root *quota_root = fs_info->quota_root;
 911         struct btrfs_path *path;
 912         struct btrfs_key key;
 913         struct extent_buffer *l;
 914         struct btrfs_qgroup_status_item *ptr;
 915         int ret;
 916         int slot;
 917
 918         key.objectid = 0;
 919         key.type = BTRFS_QGROUP_STATUS_KEY;
 920         key.offset = 0;
 921
 922         path = btrfs_alloc_path();
 923         if (!path)
 924                 return -ENOMEM;
 925
 926         ret = btrfs_search_slot(trans, quota_root, &key, path, 0, 1);
 927         if (ret > 0)
 928                 ret = -ENOENT;
 929
 930         if (ret)
 931                 goto out;
 932
 933         l = path->nodes[0];
 934         slot = path->slots[0];
 935         ptr = btrfs_item_ptr(l, slot, struct btrfs_qgroup_status_item);
 936         btrfs_set_qgroup_status_flags(l, ptr, fs_info->qgroup_flags &
 937                                       BTRFS_QGROUP_STATUS_FLAGS_MASK);
 938         btrfs_set_qgroup_status_generation(l, ptr, trans->transid);
 939         btrfs_set_qgroup_status_rescan(l, ptr,
 940                                 fs_info->qgroup_rescan_progress.objectid);
 941
 942         btrfs_mark_buffer_dirty(trans, l);
 943
 944 out:
 945         btrfs_free_path(path);
 946         return ret;
 947 }
 948
 949 /*
 950  * called with qgroup_lock held
 951  */
 952 static int btrfs_clean_quota_tree(struct btrfs_trans_handle *trans,
 953                                   struct btrfs_root *root)
 954 {
 955         struct btrfs_path *path;
 956         struct btrfs_key key;
 957         struct extent_buffer *leaf = NULL;
 958         int ret;
 959         int nr = 0;
 960
 961         path = btrfs_alloc_path();
 962         if (!path)
 963                 return -ENOMEM;
 964
 965         key.objectid = 0;
 966         key.offset = 0;
 967         key.type = 0;
 968
 969         while (1) {
 970                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 971                 if (ret < 0)
 972                         goto out;
 973                 leaf = path->nodes[0];
 974                 nr = btrfs_header_nritems(leaf);
 975                 if (!nr)
 976                         break;
 977                 /*
 978                  * delete the leaf one by one
 979                  * since the whole tree is going
 980                  * to be deleted.
 981                  */
 982                 path->slots[0] = 0;
 983                 ret = btrfs_del_items(trans, root, path, 0, nr);
 984                 if (ret)
 985                         goto out;
 986
 987                 btrfs_release_path(path);
 988         }
 989         ret = 0;
 990 out:
 991         btrfs_free_path(path);
 992         return ret;
 993 }
 994
 995 int btrfs_quota_enable(struct btrfs_fs_info *fs_info,
 996                        struct btrfs_ioctl_quota_ctl_args *quota_ctl_args)
 997 {
 998         struct btrfs_root *quota_root;
 999         struct btrfs_root *tree_root = fs_info->tree_root;
1000         struct btrfs_path *path = NULL;
1001         struct btrfs_qgroup_status_item *ptr;
1002         struct extent_buffer *leaf;
1003         struct btrfs_key key;
1004         struct btrfs_key found_key;
1005         struct btrfs_qgroup *qgroup = NULL;
1006         struct btrfs_qgroup *prealloc = NULL;
1007         struct btrfs_trans_handle *trans = NULL;
1008         struct ulist *ulist = NULL;
1009         const bool simple = (quota_ctl_args->cmd == BTRFS_QUOTA_CTL_ENABLE_SIMPLE_QUOTA);
1010         int ret = 0;
1011         int slot;
1012
1013         /*
1014          * We need to have subvol_sem write locked, to prevent races between
1015          * concurrent tasks trying to enable quotas, because we will unlock
1016          * and relock qgroup_ioctl_lock before setting fs_info->quota_root
1017          * and before setting BTRFS_FS_QUOTA_ENABLED.
1018          */
1019         lockdep_assert_held_write(&fs_info->subvol_sem);
1020
1021         if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
1022                 btrfs_err(fs_info,
1023                           "qgroups are currently unsupported in extent tree v2");
1024                 return -EINVAL;
1025         }
1026
1027         mutex_lock(&fs_info->qgroup_ioctl_lock);
1028         if (fs_info->quota_root)
1029                 goto out;
1030
1031         ulist = ulist_alloc(GFP_KERNEL);
1032         if (!ulist) {
1033                 ret = -ENOMEM;
1034                 goto out;
1035         }
1036
1037         ret = btrfs_sysfs_add_qgroups(fs_info);
1038         if (ret < 0)
1039                 goto out;
1040
1041         /*
1042          * Unlock qgroup_ioctl_lock before starting the transaction. This is to
1043          * avoid lock acquisition inversion problems (reported by lockdep) between
1044          * qgroup_ioctl_lock and the vfs freeze semaphores, acquired when we
1045          * start a transaction.
1046          * After we started the transaction lock qgroup_ioctl_lock again and
1047          * check if someone else created the quota root in the meanwhile. If so,
1048          * just return success and release the transaction handle.
1049          *
1050          * Also we don't need to worry about someone else calling
1051          * btrfs_sysfs_add_qgroups() after we unlock and getting an error because
1052          * that function returns 0 (success) when the sysfs entries already exist.
1053          */
1054         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1055
1056         /*
1057          * 1 for quota root item
1058          * 1 for BTRFS_QGROUP_STATUS item
1059          *
1060          * Yet we also need 2*n items for a QGROUP_INFO/QGROUP_LIMIT items
1061          * per subvolume. However those are not currently reserved since it
1062          * would be a lot of overkill.
1063          */
1064         trans = btrfs_start_transaction(tree_root, 2);
1065
1066         mutex_lock(&fs_info->qgroup_ioctl_lock);
1067         if (IS_ERR(trans)) {
1068                 ret = PTR_ERR(trans);
1069                 trans = NULL;
1070                 goto out;
1071         }
1072
1073         if (fs_info->quota_root)
1074                 goto out;
1075
1076         fs_info->qgroup_ulist = ulist;
1077         ulist = NULL;
1078
1079         /*
1080          * initially create the quota tree
1081          */
1082         quota_root = btrfs_create_tree(trans, BTRFS_QUOTA_TREE_OBJECTID);
1083         if (IS_ERR(quota_root)) {
1084                 ret =  PTR_ERR(quota_root);
1085                 btrfs_abort_transaction(trans, ret);
1086                 goto out;
1087         }
1088
1089         path = btrfs_alloc_path();
1090         if (!path) {
1091                 ret = -ENOMEM;
1092                 btrfs_abort_transaction(trans, ret);
1093                 goto out_free_root;
1094         }
1095
1096         key.objectid = 0;
1097         key.type = BTRFS_QGROUP_STATUS_KEY;
1098         key.offset = 0;
1099
1100         ret = btrfs_insert_empty_item(trans, quota_root, path, &key,
1101                                       sizeof(*ptr));
1102         if (ret) {
1103                 btrfs_abort_transaction(trans, ret);
1104                 goto out_free_path;
1105         }
1106
1107         leaf = path->nodes[0];
1108         ptr = btrfs_item_ptr(leaf, path->slots[0],
1109                                  struct btrfs_qgroup_status_item);
1110         btrfs_set_qgroup_status_generation(leaf, ptr, trans->transid);
1111         btrfs_set_qgroup_status_version(leaf, ptr, BTRFS_QGROUP_STATUS_VERSION);
1112         fs_info->qgroup_flags = BTRFS_QGROUP_STATUS_FLAG_ON;
1113         if (simple) {
1114                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE;
1115                 btrfs_set_qgroup_status_enable_gen(leaf, ptr, trans->transid);
1116         } else {
1117                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1118         }
1119         btrfs_set_qgroup_status_flags(leaf, ptr, fs_info->qgroup_flags &
1120                                       BTRFS_QGROUP_STATUS_FLAGS_MASK);
1121         btrfs_set_qgroup_status_rescan(leaf, ptr, 0);
1122
1123         btrfs_mark_buffer_dirty(trans, leaf);
1124
1125         key.objectid = 0;
1126         key.type = BTRFS_ROOT_REF_KEY;
1127         key.offset = 0;
1128
1129         btrfs_release_path(path);
1130         ret = btrfs_search_slot_for_read(tree_root, &key, path, 1, 0);
1131         if (ret > 0)
1132                 goto out_add_root;
1133         if (ret < 0) {
1134                 btrfs_abort_transaction(trans, ret);
1135                 goto out_free_path;
1136         }
1137
1138         while (1) {
1139                 slot = path->slots[0];
1140                 leaf = path->nodes[0];
1141                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
1142
1143                 if (found_key.type == BTRFS_ROOT_REF_KEY) {
1144
1145                         /* Release locks on tree_root before we access quota_root */
1146                         btrfs_release_path(path);
1147
1148                         /* We should not have a stray @prealloc pointer. */
1149                         ASSERT(prealloc == NULL);
1150                         prealloc = kzalloc(sizeof(*prealloc), GFP_NOFS);
1151                         if (!prealloc) {
1152                                 ret = -ENOMEM;
1153                                 btrfs_abort_transaction(trans, ret);
1154                                 goto out_free_path;
1155                         }
1156
1157                         ret = add_qgroup_item(trans, quota_root,
1158                                               found_key.offset);
1159                         if (ret) {
1160                                 btrfs_abort_transaction(trans, ret);
1161                                 goto out_free_path;
1162                         }
1163
1164                         qgroup = add_qgroup_rb(fs_info, prealloc, found_key.offset);
1165                         prealloc = NULL;
1166                         if (IS_ERR(qgroup)) {
1167                                 ret = PTR_ERR(qgroup);
1168                                 btrfs_abort_transaction(trans, ret);
1169                                 goto out_free_path;
1170                         }
1171                         ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1172                         if (ret < 0) {
1173                                 btrfs_abort_transaction(trans, ret);
1174                                 goto out_free_path;
1175                         }
1176                         ret = btrfs_search_slot_for_read(tree_root, &found_key,
1177                                                          path, 1, 0);
1178                         if (ret < 0) {
1179                                 btrfs_abort_transaction(trans, ret);
1180                                 goto out_free_path;
1181                         }
1182                         if (ret > 0) {
1183                                 /*
1184                                  * Shouldn't happen, but in case it does we
1185                                  * don't need to do the btrfs_next_item, just
1186                                  * continue.
1187                                  */
1188                                 continue;
1189                         }
1190                 }
1191                 ret = btrfs_next_item(tree_root, path);
1192                 if (ret < 0) {
1193                         btrfs_abort_transaction(trans, ret);
1194                         goto out_free_path;
1195                 }
1196                 if (ret)
1197                         break;
1198         }
1199
1200 out_add_root:
1201         btrfs_release_path(path);
1202         ret = add_qgroup_item(trans, quota_root, BTRFS_FS_TREE_OBJECTID);
1203         if (ret) {
1204                 btrfs_abort_transaction(trans, ret);
1205                 goto out_free_path;
1206         }
1207
1208         ASSERT(prealloc == NULL);
1209         prealloc = kzalloc(sizeof(*prealloc), GFP_NOFS);
1210         if (!prealloc) {
1211                 ret = -ENOMEM;
1212                 goto out_free_path;
1213         }
1214         qgroup = add_qgroup_rb(fs_info, prealloc, BTRFS_FS_TREE_OBJECTID);
1215         prealloc = NULL;
1216         ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1217         if (ret < 0) {
1218                 btrfs_abort_transaction(trans, ret);
1219                 goto out_free_path;
1220         }
1221
1222         fs_info->qgroup_enable_gen = trans->transid;
1223
1224         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1225         /*
1226          * Commit the transaction while not holding qgroup_ioctl_lock, to avoid
1227          * a deadlock with tasks concurrently doing other qgroup operations, such
1228          * adding/removing qgroups or adding/deleting qgroup relations for example,
1229          * because all qgroup operations first start or join a transaction and then
1230          * lock the qgroup_ioctl_lock mutex.
1231          * We are safe from a concurrent task trying to enable quotas, by calling
1232          * this function, since we are serialized by fs_info->subvol_sem.
1233          */
1234         ret = btrfs_commit_transaction(trans);
1235         trans = NULL;
1236         mutex_lock(&fs_info->qgroup_ioctl_lock);
1237         if (ret)
1238                 goto out_free_path;
1239
1240         /*
1241          * Set quota enabled flag after committing the transaction, to avoid
1242          * deadlocks on fs_info->qgroup_ioctl_lock with concurrent snapshot
1243          * creation.
1244          */
1245         spin_lock(&fs_info->qgroup_lock);
1246         fs_info->quota_root = quota_root;
1247         set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1248         if (simple)
1249                 btrfs_set_fs_incompat(fs_info, SIMPLE_QUOTA);
1250         spin_unlock(&fs_info->qgroup_lock);
1251
1252         /* Skip rescan for simple qgroups. */
1253         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
1254                 goto out_free_path;
1255
1256         ret = qgroup_rescan_init(fs_info, 0, 1);
1257         if (!ret) {
1258                 qgroup_rescan_zero_tracking(fs_info);
1259                 fs_info->qgroup_rescan_running = true;
1260                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
1261                                  &fs_info->qgroup_rescan_work);
1262         } else {
1263                 /*
1264                  * We have set both BTRFS_FS_QUOTA_ENABLED and
1265                  * BTRFS_QGROUP_STATUS_FLAG_ON, so we can only fail with
1266                  * -EINPROGRESS. That can happen because someone started the
1267                  * rescan worker by calling quota rescan ioctl before we
1268                  * attempted to initialize the rescan worker. Failure due to
1269                  * quotas disabled in the meanwhile is not possible, because
1270                  * we are holding a write lock on fs_info->subvol_sem, which
1271                  * is also acquired when disabling quotas.
1272                  * Ignore such error, and any other error would need to undo
1273                  * everything we did in the transaction we just committed.
1274                  */
1275                 ASSERT(ret == -EINPROGRESS);
1276                 ret = 0;
1277         }
1278
1279 out_free_path:
1280         btrfs_free_path(path);
1281 out_free_root:
1282         if (ret)
1283                 btrfs_put_root(quota_root);
1284 out:
1285         if (ret) {
1286                 ulist_free(fs_info->qgroup_ulist);
1287                 fs_info->qgroup_ulist = NULL;
1288                 btrfs_sysfs_del_qgroups(fs_info);
1289         }
1290         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1291         if (ret && trans)
1292                 btrfs_end_transaction(trans);
1293         else if (trans)
1294                 ret = btrfs_end_transaction(trans);
1295         ulist_free(ulist);
1296         kfree(prealloc);
1297         return ret;
1298 }
1299
1300 /*
1301  * It is possible to have outstanding ordered extents which reserved bytes
1302  * before we disabled. We need to fully flush delalloc, ordered extents, and a
1303  * commit to ensure that we don't leak such reservations, only to have them
1304  * come back if we re-enable.
1305  *
1306  * - enable simple quotas
1307  * - reserve space
1308  * - release it, store rsv_bytes in OE
1309  * - disable quotas
1310  * - enable simple quotas (qgroup rsv are all 0)
1311  * - OE finishes
1312  * - run delayed refs
1313  * - free rsv_bytes, resulting in miscounting or even underflow
1314  */
1315 static int flush_reservations(struct btrfs_fs_info *fs_info)
1316 {
1317         struct btrfs_trans_handle *trans;
1318         int ret;
1319
1320         ret = btrfs_start_delalloc_roots(fs_info, LONG_MAX, false);
1321         if (ret)
1322                 return ret;
1323         btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1324         trans = btrfs_join_transaction(fs_info->tree_root);
1325         if (IS_ERR(trans))
1326                 return PTR_ERR(trans);
1327         ret = btrfs_commit_transaction(trans);
1328
1329         return ret;
1330 }
1331
1332 int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
1333 {
1334         struct btrfs_root *quota_root;
1335         struct btrfs_trans_handle *trans = NULL;
1336         int ret = 0;
1337
1338         /*
1339          * We need to have subvol_sem write locked to prevent races with
1340          * snapshot creation.
1341          */
1342         lockdep_assert_held_write(&fs_info->subvol_sem);
1343
1344         /*
1345          * Lock the cleaner mutex to prevent races with concurrent relocation,
1346          * because relocation may be building backrefs for blocks of the quota
1347          * root while we are deleting the root. This is like dropping fs roots
1348          * of deleted snapshots/subvolumes, we need the same protection.
1349          *
1350          * This also prevents races between concurrent tasks trying to disable
1351          * quotas, because we will unlock and relock qgroup_ioctl_lock across
1352          * BTRFS_FS_QUOTA_ENABLED changes.
1353          */
1354         mutex_lock(&fs_info->cleaner_mutex);
1355
1356         mutex_lock(&fs_info->qgroup_ioctl_lock);
1357         if (!fs_info->quota_root)
1358                 goto out;
1359
1360         /*
1361          * Unlock the qgroup_ioctl_lock mutex before waiting for the rescan worker to
1362          * complete. Otherwise we can deadlock because btrfs_remove_qgroup() needs
1363          * to lock that mutex while holding a transaction handle and the rescan
1364          * worker needs to commit a transaction.
1365          */
1366         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1367
1368         /*
1369          * Request qgroup rescan worker to complete and wait for it. This wait
1370          * must be done before transaction start for quota disable since it may
1371          * deadlock with transaction by the qgroup rescan worker.
1372          */
1373         clear_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1374         btrfs_qgroup_wait_for_completion(fs_info, false);
1375
1376         ret = flush_reservations(fs_info);
1377         if (ret)
1378                 goto out_unlock_cleaner;
1379
1380         /*
1381          * 1 For the root item
1382          *
1383          * We should also reserve enough items for the quota tree deletion in
1384          * btrfs_clean_quota_tree but this is not done.
1385          *
1386          * Also, we must always start a transaction without holding the mutex
1387          * qgroup_ioctl_lock, see btrfs_quota_enable().
1388          */
1389         trans = btrfs_start_transaction(fs_info->tree_root, 1);
1390
1391         mutex_lock(&fs_info->qgroup_ioctl_lock);
1392         if (IS_ERR(trans)) {
1393                 ret = PTR_ERR(trans);
1394                 trans = NULL;
1395                 set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
1396                 goto out;
1397         }
1398
1399         if (!fs_info->quota_root)
1400                 goto out;
1401
1402         spin_lock(&fs_info->qgroup_lock);
1403         quota_root = fs_info->quota_root;
1404         fs_info->quota_root = NULL;
1405         fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
1406         fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE;
1407         fs_info->qgroup_drop_subtree_thres = BTRFS_MAX_LEVEL;
1408         spin_unlock(&fs_info->qgroup_lock);
1409
1410         btrfs_free_qgroup_config(fs_info);
1411
1412         ret = btrfs_clean_quota_tree(trans, quota_root);
1413         if (ret) {
1414                 btrfs_abort_transaction(trans, ret);
1415                 goto out;
1416         }
1417
1418         ret = btrfs_del_root(trans, &quota_root->root_key);
1419         if (ret) {
1420                 btrfs_abort_transaction(trans, ret);
1421                 goto out;
1422         }
1423
1424         spin_lock(&fs_info->trans_lock);
1425         list_del(&quota_root->dirty_list);
1426         spin_unlock(&fs_info->trans_lock);
1427
1428         btrfs_tree_lock(quota_root->node);
1429         btrfs_clear_buffer_dirty(trans, quota_root->node);
1430         btrfs_tree_unlock(quota_root->node);
1431         btrfs_free_tree_block(trans, btrfs_root_id(quota_root),
1432                               quota_root->node, 0, 1);
1433
1434         btrfs_put_root(quota_root);
1435
1436 out:
1437         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1438         if (ret && trans)
1439                 btrfs_end_transaction(trans);
1440         else if (trans)
1441                 ret = btrfs_commit_transaction(trans);
1442 out_unlock_cleaner:
1443         mutex_unlock(&fs_info->cleaner_mutex);
1444
1445         return ret;
1446 }
1447
1448 static void qgroup_dirty(struct btrfs_fs_info *fs_info,
1449                          struct btrfs_qgroup *qgroup)
1450 {
1451         if (list_empty(&qgroup->dirty))
1452                 list_add(&qgroup->dirty, &fs_info->dirty_qgroups);
1453 }
1454
1455 static void qgroup_iterator_add(struct list_head *head, struct btrfs_qgroup *qgroup)
1456 {
1457         if (!list_empty(&qgroup->iterator))
1458                 return;
1459
1460         list_add_tail(&qgroup->iterator, head);
1461 }
1462
1463 static void qgroup_iterator_clean(struct list_head *head)
1464 {
1465         while (!list_empty(head)) {
1466                 struct btrfs_qgroup *qgroup;
1467
1468                 qgroup = list_first_entry(head, struct btrfs_qgroup, iterator);
1469                 list_del_init(&qgroup->iterator);
1470         }
1471 }
1472
1473 /*
1474  * The easy accounting, we're updating qgroup relationship whose child qgroup
1475  * only has exclusive extents.
1476  *
1477  * In this case, all exclusive extents will also be exclusive for parent, so
1478  * excl/rfer just get added/removed.
1479  *
1480  * So is qgroup reservation space, which should also be added/removed to
1481  * parent.
1482  * Or when child tries to release reservation space, parent will underflow its
1483  * reservation (for relationship adding case).
1484  *
1485  * Caller should hold fs_info->qgroup_lock.
1486  */
1487 static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info, u64 ref_root,
1488                                     struct btrfs_qgroup *src, int sign)
1489 {
1490         struct btrfs_qgroup *qgroup;
1491         struct btrfs_qgroup *cur;
1492         LIST_HEAD(qgroup_list);
1493         u64 num_bytes = src->excl;
1494         int ret = 0;
1495
1496         qgroup = find_qgroup_rb(fs_info, ref_root);
1497         if (!qgroup)
1498                 goto out;
1499
1500         qgroup_iterator_add(&qgroup_list, qgroup);
1501         list_for_each_entry(cur, &qgroup_list, iterator) {
1502                 struct btrfs_qgroup_list *glist;
1503
1504                 qgroup->rfer += sign * num_bytes;
1505                 qgroup->rfer_cmpr += sign * num_bytes;
1506
1507                 WARN_ON(sign < 0 && qgroup->excl < num_bytes);
1508                 qgroup->excl += sign * num_bytes;
1509                 qgroup->excl_cmpr += sign * num_bytes;
1510
1511                 if (sign > 0)
1512                         qgroup_rsv_add_by_qgroup(fs_info, qgroup, src);
1513                 else
1514                         qgroup_rsv_release_by_qgroup(fs_info, qgroup, src);
1515                 qgroup_dirty(fs_info, qgroup);
1516
1517                 /* Append parent qgroups to @qgroup_list. */
1518                 list_for_each_entry(glist, &qgroup->groups, next_group)
1519                         qgroup_iterator_add(&qgroup_list, glist->group);
1520         }
1521         ret = 0;
1522 out:
1523         qgroup_iterator_clean(&qgroup_list);
1524         return ret;
1525 }
1526
1527
1528 /*
1529  * Quick path for updating qgroup with only excl refs.
1530  *
1531  * In that case, just update all parent will be enough.
1532  * Or we needs to do a full rescan.
1533  * Caller should also hold fs_info->qgroup_lock.
1534  *
1535  * Return 0 for quick update, return >0 for need to full rescan
1536  * and mark INCONSISTENT flag.
1537  * Return < 0 for other error.
1538  */
1539 static int quick_update_accounting(struct btrfs_fs_info *fs_info,
1540                                    u64 src, u64 dst, int sign)
1541 {
1542         struct btrfs_qgroup *qgroup;
1543         int ret = 1;
1544         int err = 0;
1545
1546         qgroup = find_qgroup_rb(fs_info, src);
1547         if (!qgroup)
1548                 goto out;
1549         if (qgroup->excl == qgroup->rfer) {
1550                 ret = 0;
1551                 err = __qgroup_excl_accounting(fs_info, dst, qgroup, sign);
1552                 if (err < 0) {
1553                         ret = err;
1554                         goto out;
1555                 }
1556         }
1557 out:
1558         if (ret)
1559                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
1560         return ret;
1561 }
1562
1563 int btrfs_add_qgroup_relation(struct btrfs_trans_handle *trans, u64 src, u64 dst)
1564 {
1565         struct btrfs_fs_info *fs_info = trans->fs_info;
1566         struct btrfs_qgroup *parent;
1567         struct btrfs_qgroup *member;
1568         struct btrfs_qgroup_list *list;
1569         struct btrfs_qgroup_list *prealloc = NULL;
1570         int ret = 0;
1571
1572         /* Check the level of src and dst first */
1573         if (btrfs_qgroup_level(src) >= btrfs_qgroup_level(dst))
1574                 return -EINVAL;
1575
1576         mutex_lock(&fs_info->qgroup_ioctl_lock);
1577         if (!fs_info->quota_root) {
1578                 ret = -ENOTCONN;
1579                 goto out;
1580         }
1581         member = find_qgroup_rb(fs_info, src);
1582         parent = find_qgroup_rb(fs_info, dst);
1583         if (!member || !parent) {
1584                 ret = -EINVAL;
1585                 goto out;
1586         }
1587
1588         /* check if such qgroup relation exist firstly */
1589         list_for_each_entry(list, &member->groups, next_group) {
1590                 if (list->group == parent) {
1591                         ret = -EEXIST;
1592                         goto out;
1593                 }
1594         }
1595
1596         prealloc = kzalloc(sizeof(*list), GFP_NOFS);
1597         if (!prealloc) {
1598                 ret = -ENOMEM;
1599                 goto out;
1600         }
1601         ret = add_qgroup_relation_item(trans, src, dst);
1602         if (ret)
1603                 goto out;
1604
1605         ret = add_qgroup_relation_item(trans, dst, src);
1606         if (ret) {
1607                 del_qgroup_relation_item(trans, src, dst);
1608                 goto out;
1609         }
1610
1611         spin_lock(&fs_info->qgroup_lock);
1612         ret = __add_relation_rb(prealloc, member, parent);
1613         prealloc = NULL;
1614         if (ret < 0) {
1615                 spin_unlock(&fs_info->qgroup_lock);
1616                 goto out;
1617         }
1618         ret = quick_update_accounting(fs_info, src, dst, 1);
1619         spin_unlock(&fs_info->qgroup_lock);
1620 out:
1621         kfree(prealloc);
1622         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1623         return ret;
1624 }
1625
1626 static int __del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1627                                  u64 dst)
1628 {
1629         struct btrfs_fs_info *fs_info = trans->fs_info;
1630         struct btrfs_qgroup *parent;
1631         struct btrfs_qgroup *member;
1632         struct btrfs_qgroup_list *list;
1633         bool found = false;
1634         int ret = 0;
1635         int ret2;
1636
1637         if (!fs_info->quota_root) {
1638                 ret = -ENOTCONN;
1639                 goto out;
1640         }
1641
1642         member = find_qgroup_rb(fs_info, src);
1643         parent = find_qgroup_rb(fs_info, dst);
1644         /*
1645          * The parent/member pair doesn't exist, then try to delete the dead
1646          * relation items only.
1647          */
1648         if (!member || !parent)
1649                 goto delete_item;
1650
1651         /* check if such qgroup relation exist firstly */
1652         list_for_each_entry(list, &member->groups, next_group) {
1653                 if (list->group == parent) {
1654                         found = true;
1655                         break;
1656                 }
1657         }
1658
1659 delete_item:
1660         ret = del_qgroup_relation_item(trans, src, dst);
1661         if (ret < 0 && ret != -ENOENT)
1662                 goto out;
1663         ret2 = del_qgroup_relation_item(trans, dst, src);
1664         if (ret2 < 0 && ret2 != -ENOENT)
1665                 goto out;
1666
1667         /* At least one deletion succeeded, return 0 */
1668         if (!ret || !ret2)
1669                 ret = 0;
1670
1671         if (found) {
1672                 spin_lock(&fs_info->qgroup_lock);
1673                 del_relation_rb(fs_info, src, dst);
1674                 ret = quick_update_accounting(fs_info, src, dst, -1);
1675                 spin_unlock(&fs_info->qgroup_lock);
1676         }
1677 out:
1678         return ret;
1679 }
1680
1681 int btrfs_del_qgroup_relation(struct btrfs_trans_handle *trans, u64 src,
1682                               u64 dst)
1683 {
1684         struct btrfs_fs_info *fs_info = trans->fs_info;
1685         int ret = 0;
1686
1687         mutex_lock(&fs_info->qgroup_ioctl_lock);
1688         ret = __del_qgroup_relation(trans, src, dst);
1689         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1690
1691         return ret;
1692 }
1693
1694 int btrfs_create_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1695 {
1696         struct btrfs_fs_info *fs_info = trans->fs_info;
1697         struct btrfs_root *quota_root;
1698         struct btrfs_qgroup *qgroup;
1699         struct btrfs_qgroup *prealloc = NULL;
1700         int ret = 0;
1701
1702         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED)
1703                 return 0;
1704
1705         mutex_lock(&fs_info->qgroup_ioctl_lock);
1706         if (!fs_info->quota_root) {
1707                 ret = -ENOTCONN;
1708                 goto out;
1709         }
1710         quota_root = fs_info->quota_root;
1711         qgroup = find_qgroup_rb(fs_info, qgroupid);
1712         if (qgroup) {
1713                 ret = -EEXIST;
1714                 goto out;
1715         }
1716
1717         prealloc = kzalloc(sizeof(*prealloc), GFP_NOFS);
1718         if (!prealloc) {
1719                 ret = -ENOMEM;
1720                 goto out;
1721         }
1722
1723         ret = add_qgroup_item(trans, quota_root, qgroupid);
1724         if (ret)
1725                 goto out;
1726
1727         spin_lock(&fs_info->qgroup_lock);
1728         qgroup = add_qgroup_rb(fs_info, prealloc, qgroupid);
1729         spin_unlock(&fs_info->qgroup_lock);
1730         prealloc = NULL;
1731
1732         ret = btrfs_sysfs_add_one_qgroup(fs_info, qgroup);
1733 out:
1734         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1735         kfree(prealloc);
1736         return ret;
1737 }
1738
1739 static bool qgroup_has_usage(struct btrfs_qgroup *qgroup)
1740 {
1741         return (qgroup->rfer > 0 || qgroup->rfer_cmpr > 0 ||
1742                 qgroup->excl > 0 || qgroup->excl_cmpr > 0 ||
1743                 qgroup->rsv.values[BTRFS_QGROUP_RSV_DATA] > 0 ||
1744                 qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PREALLOC] > 0 ||
1745                 qgroup->rsv.values[BTRFS_QGROUP_RSV_META_PERTRANS] > 0);
1746 }
1747
1748 int btrfs_remove_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid)
1749 {
1750         struct btrfs_fs_info *fs_info = trans->fs_info;
1751         struct btrfs_qgroup *qgroup;
1752         struct btrfs_qgroup_list *list;
1753         int ret = 0;
1754
1755         mutex_lock(&fs_info->qgroup_ioctl_lock);
1756         if (!fs_info->quota_root) {
1757                 ret = -ENOTCONN;
1758                 goto out;
1759         }
1760
1761         qgroup = find_qgroup_rb(fs_info, qgroupid);
1762         if (!qgroup) {
1763                 ret = -ENOENT;
1764                 goto out;
1765         }
1766
1767         if (is_fstree(qgroupid) && qgroup_has_usage(qgroup)) {
1768                 ret = -EBUSY;
1769                 goto out;
1770         }
1771
1772         /* Check if there are no children of this qgroup */
1773         if (!list_empty(&qgroup->members)) {
1774                 ret = -EBUSY;
1775                 goto out;
1776         }
1777
1778         ret = del_qgroup_item(trans, qgroupid);
1779         if (ret && ret != -ENOENT)
1780                 goto out;
1781
1782         while (!list_empty(&qgroup->groups)) {
1783                 list = list_first_entry(&qgroup->groups,
1784                                         struct btrfs_qgroup_list, next_group);
1785                 ret = __del_qgroup_relation(trans, qgroupid,
1786                                             list->group->qgroupid);
1787                 if (ret)
1788                         goto out;
1789         }
1790
1791         spin_lock(&fs_info->qgroup_lock);
1792         del_qgroup_rb(fs_info, qgroupid);
1793         spin_unlock(&fs_info->qgroup_lock);
1794
1795         /*
1796          * Remove the qgroup from sysfs now without holding the qgroup_lock
1797          * spinlock, since the sysfs_remove_group() function needs to take
1798          * the mutex kernfs_mutex through kernfs_remove_by_name_ns().
1799          */
1800         btrfs_sysfs_del_one_qgroup(fs_info, qgroup);
1801         kfree(qgroup);
1802 out:
1803         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1804         return ret;
1805 }
1806
1807 int btrfs_limit_qgroup(struct btrfs_trans_handle *trans, u64 qgroupid,
1808                        struct btrfs_qgroup_limit *limit)
1809 {
1810         struct btrfs_fs_info *fs_info = trans->fs_info;
1811         struct btrfs_qgroup *qgroup;
1812         int ret = 0;
1813         /* Sometimes we would want to clear the limit on this qgroup.
1814          * To meet this requirement, we treat the -1 as a special value
1815          * which tell kernel to clear the limit on this qgroup.
1816          */
1817         const u64 CLEAR_VALUE = -1;
1818
1819         mutex_lock(&fs_info->qgroup_ioctl_lock);
1820         if (!fs_info->quota_root) {
1821                 ret = -ENOTCONN;
1822                 goto out;
1823         }
1824
1825         qgroup = find_qgroup_rb(fs_info, qgroupid);
1826         if (!qgroup) {
1827                 ret = -ENOENT;
1828                 goto out;
1829         }
1830
1831         spin_lock(&fs_info->qgroup_lock);
1832         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_RFER) {
1833                 if (limit->max_rfer == CLEAR_VALUE) {
1834                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1835                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_RFER;
1836                         qgroup->max_rfer = 0;
1837                 } else {
1838                         qgroup->max_rfer = limit->max_rfer;
1839                 }
1840         }
1841         if (limit->flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) {
1842                 if (limit->max_excl == CLEAR_VALUE) {
1843                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1844                         limit->flags &= ~BTRFS_QGROUP_LIMIT_MAX_EXCL;
1845                         qgroup->max_excl = 0;
1846                 } else {
1847                         qgroup->max_excl = limit->max_excl;
1848                 }
1849         }
1850         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_RFER) {
1851                 if (limit->rsv_rfer == CLEAR_VALUE) {
1852                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1853                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_RFER;
1854                         qgroup->rsv_rfer = 0;
1855                 } else {
1856                         qgroup->rsv_rfer = limit->rsv_rfer;
1857                 }
1858         }
1859         if (limit->flags & BTRFS_QGROUP_LIMIT_RSV_EXCL) {
1860                 if (limit->rsv_excl == CLEAR_VALUE) {
1861                         qgroup->lim_flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1862                         limit->flags &= ~BTRFS_QGROUP_LIMIT_RSV_EXCL;
1863                         qgroup->rsv_excl = 0;
1864                 } else {
1865                         qgroup->rsv_excl = limit->rsv_excl;
1866                 }
1867         }
1868         qgroup->lim_flags |= limit->flags;
1869
1870         spin_unlock(&fs_info->qgroup_lock);
1871
1872         ret = update_qgroup_limit_item(trans, qgroup);
1873         if (ret) {
1874                 qgroup_mark_inconsistent(fs_info);
1875                 btrfs_info(fs_info, "unable to update quota limit for %llu",
1876                        qgroupid);
1877         }
1878
1879 out:
1880         mutex_unlock(&fs_info->qgroup_ioctl_lock);
1881         return ret;
1882 }
1883
1884 /*
1885  * Inform qgroup to trace one dirty extent, its info is recorded in @record.
1886  * So qgroup can account it at transaction committing time.
1887  *
1888  * No lock version, caller must acquire delayed ref lock and allocated memory,
1889  * then call btrfs_qgroup_trace_extent_post() after exiting lock context.
1890  *
1891  * Return 0 for success insert
1892  * Return >0 for existing record, caller can free @record safely.
1893  * Error is not possible
1894  */
1895 int btrfs_qgroup_trace_extent_nolock(struct btrfs_fs_info *fs_info,
1896                                 struct btrfs_delayed_ref_root *delayed_refs,
1897                                 struct btrfs_qgroup_extent_record *record)
1898 {
1899         struct rb_node **p = &delayed_refs->dirty_extent_root.rb_node;
1900         struct rb_node *parent_node = NULL;
1901         struct btrfs_qgroup_extent_record *entry;
1902         u64 bytenr = record->bytenr;
1903
1904         if (!btrfs_qgroup_full_accounting(fs_info))
1905                 return 1;
1906
1907         lockdep_assert_held(&delayed_refs->lock);
1908         trace_btrfs_qgroup_trace_extent(fs_info, record);
1909
1910         while (*p) {
1911                 parent_node = *p;
1912                 entry = rb_entry(parent_node, struct btrfs_qgroup_extent_record,
1913                                  node);
1914                 if (bytenr < entry->bytenr) {
1915                         p = &(*p)->rb_left;
1916                 } else if (bytenr > entry->bytenr) {
1917                         p = &(*p)->rb_right;
1918                 } else {
1919                         if (record->data_rsv && !entry->data_rsv) {
1920                                 entry->data_rsv = record->data_rsv;
1921                                 entry->data_rsv_refroot =
1922                                         record->data_rsv_refroot;
1923                         }
1924                         return 1;
1925                 }
1926         }
1927
1928         rb_link_node(&record->node, parent_node, p);
1929         rb_insert_color(&record->node, &delayed_refs->dirty_extent_root);
1930         return 0;
1931 }
1932
1933 /*
1934  * Post handler after qgroup_trace_extent_nolock().
1935  *
1936  * NOTE: Current qgroup does the expensive backref walk at transaction
1937  * committing time with TRANS_STATE_COMMIT_DOING, this blocks incoming
1938  * new transaction.
1939  * This is designed to allow btrfs_find_all_roots() to get correct new_roots
1940  * result.
1941  *
1942  * However for old_roots there is no need to do backref walk at that time,
1943  * since we search commit roots to walk backref and result will always be
1944  * correct.
1945  *
1946  * Due to the nature of no lock version, we can't do backref there.
1947  * So we must call btrfs_qgroup_trace_extent_post() after exiting
1948  * spinlock context.
1949  *
1950  * TODO: If we can fix and prove btrfs_find_all_roots() can get correct result
1951  * using current root, then we can move all expensive backref walk out of
1952  * transaction committing, but not now as qgroup accounting will be wrong again.
1953  */
1954 int btrfs_qgroup_trace_extent_post(struct btrfs_trans_handle *trans,
1955                                    struct btrfs_qgroup_extent_record *qrecord)
1956 {
1957         struct btrfs_backref_walk_ctx ctx = { 0 };
1958         int ret;
1959
1960         if (!btrfs_qgroup_full_accounting(trans->fs_info))
1961                 return 0;
1962         /*
1963          * We are always called in a context where we are already holding a
1964          * transaction handle. Often we are called when adding a data delayed
1965          * reference from btrfs_truncate_inode_items() (truncating or unlinking),
1966          * in which case we will be holding a write lock on extent buffer from a
1967          * subvolume tree. In this case we can't allow btrfs_find_all_roots() to
1968          * acquire fs_info->commit_root_sem, because that is a higher level lock
1969          * that must be acquired before locking any extent buffers.
1970          *
1971          * So we want btrfs_find_all_roots() to not acquire the commit_root_sem
1972          * but we can't pass it a non-NULL transaction handle, because otherwise
1973          * it would not use commit roots and would lock extent buffers, causing
1974          * a deadlock if it ends up trying to read lock the same extent buffer
1975          * that was previously write locked at btrfs_truncate_inode_items().
1976          *
1977          * So pass a NULL transaction handle to btrfs_find_all_roots() and
1978          * explicitly tell it to not acquire the commit_root_sem - if we are
1979          * holding a transaction handle we don't need its protection.
1980          */
1981         ASSERT(trans != NULL);
1982
1983         if (trans->fs_info->qgroup_flags & BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING)
1984                 return 0;
1985
1986         ctx.bytenr = qrecord->bytenr;
1987         ctx.fs_info = trans->fs_info;
1988
1989         ret = btrfs_find_all_roots(&ctx, true);
1990         if (ret < 0) {
1991                 qgroup_mark_inconsistent(trans->fs_info);
1992                 btrfs_warn(trans->fs_info,
1993 "error accounting new delayed refs extent (err code: %d), quota inconsistent",
1994                         ret);
1995                 return 0;
1996         }
1997
1998         /*
1999          * Here we don't need to get the lock of
2000          * trans->transaction->delayed_refs, since inserted qrecord won't
2001          * be deleted, only qrecord->node may be modified (new qrecord insert)
2002          *
2003          * So modifying qrecord->old_roots is safe here
2004          */
2005         qrecord->old_roots = ctx.roots;
2006         return 0;
2007 }
2008
2009 /*
2010  * Inform qgroup to trace one dirty extent, specified by @bytenr and
2011  * @num_bytes.
2012  * So qgroup can account it at commit trans time.
2013  *
2014  * Better encapsulated version, with memory allocation and backref walk for
2015  * commit roots.
2016  * So this can sleep.
2017  *
2018  * Return 0 if the operation is done.
2019  * Return <0 for error, like memory allocation failure or invalid parameter
2020  * (NULL trans)
2021  */
2022 int btrfs_qgroup_trace_extent(struct btrfs_trans_handle *trans, u64 bytenr,
2023                               u64 num_bytes)
2024 {
2025         struct btrfs_fs_info *fs_info = trans->fs_info;
2026         struct btrfs_qgroup_extent_record *record;
2027         struct btrfs_delayed_ref_root *delayed_refs;
2028         int ret;
2029
2030         if (!btrfs_qgroup_full_accounting(fs_info) || bytenr == 0 || num_bytes == 0)
2031                 return 0;
2032         record = kzalloc(sizeof(*record), GFP_NOFS);
2033         if (!record)
2034                 return -ENOMEM;
2035
2036         delayed_refs = &trans->transaction->delayed_refs;
2037         record->bytenr = bytenr;
2038         record->num_bytes = num_bytes;
2039         record->old_roots = NULL;
2040
2041         spin_lock(&delayed_refs->lock);
2042         ret = btrfs_qgroup_trace_extent_nolock(fs_info, delayed_refs, record);
2043         spin_unlock(&delayed_refs->lock);
2044         if (ret > 0) {
2045                 kfree(record);
2046                 return 0;
2047         }
2048         return btrfs_qgroup_trace_extent_post(trans, record);
2049 }
2050
2051 /*
2052  * Inform qgroup to trace all leaf items of data
2053  *
2054  * Return 0 for success
2055  * Return <0 for error(ENOMEM)
2056  */
2057 int btrfs_qgroup_trace_leaf_items(struct btrfs_trans_handle *trans,
2058                                   struct extent_buffer *eb)
2059 {
2060         struct btrfs_fs_info *fs_info = trans->fs_info;
2061         int nr = btrfs_header_nritems(eb);
2062         int i, extent_type, ret;
2063         struct btrfs_key key;
2064         struct btrfs_file_extent_item *fi;
2065         u64 bytenr, num_bytes;
2066
2067         /* We can be called directly from walk_up_proc() */
2068         if (!btrfs_qgroup_full_accounting(fs_info))
2069                 return 0;
2070
2071         for (i = 0; i < nr; i++) {
2072                 btrfs_item_key_to_cpu(eb, &key, i);
2073
2074                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2075                         continue;
2076
2077                 fi = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
2078                 /* filter out non qgroup-accountable extents  */
2079                 extent_type = btrfs_file_extent_type(eb, fi);
2080
2081                 if (extent_type == BTRFS_FILE_EXTENT_INLINE)
2082                         continue;
2083
2084                 bytenr = btrfs_file_extent_disk_bytenr(eb, fi);
2085                 if (!bytenr)
2086                         continue;
2087
2088                 num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
2089
2090                 ret = btrfs_qgroup_trace_extent(trans, bytenr, num_bytes);
2091                 if (ret)
2092                         return ret;
2093         }
2094         cond_resched();
2095         return 0;
2096 }
2097
2098 /*
2099  * Walk up the tree from the bottom, freeing leaves and any interior
2100  * nodes which have had all slots visited. If a node (leaf or
2101  * interior) is freed, the node above it will have it's slot
2102  * incremented. The root node will never be freed.
2103  *
2104  * At the end of this function, we should have a path which has all
2105  * slots incremented to the next position for a search. If we need to
2106  * read a new node it will be NULL and the node above it will have the
2107  * correct slot selected for a later read.
2108  *
2109  * If we increment the root nodes slot counter past the number of
2110  * elements, 1 is returned to signal completion of the search.
2111  */
2112 static int adjust_slots_upwards(struct btrfs_path *path, int root_level)
2113 {
2114         int level = 0;
2115         int nr, slot;
2116         struct extent_buffer *eb;
2117
2118         if (root_level == 0)
2119                 return 1;
2120
2121         while (level <= root_level) {
2122                 eb = path->nodes[level];
2123                 nr = btrfs_header_nritems(eb);
2124                 path->slots[level]++;
2125                 slot = path->slots[level];
2126                 if (slot >= nr || level == 0) {
2127                         /*
2128                          * Don't free the root -  we will detect this
2129                          * condition after our loop and return a
2130                          * positive value for caller to stop walking the tree.
2131                          */
2132                         if (level != root_level) {
2133                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
2134                                 path->locks[level] = 0;
2135
2136                                 free_extent_buffer(eb);
2137                                 path->nodes[level] = NULL;
2138                                 path->slots[level] = 0;
2139                         }
2140                 } else {
2141                         /*
2142                          * We have a valid slot to walk back down
2143                          * from. Stop here so caller can process these
2144                          * new nodes.
2145                          */
2146                         break;
2147                 }
2148
2149                 level++;
2150         }
2151
2152         eb = path->nodes[root_level];
2153         if (path->slots[root_level] >= btrfs_header_nritems(eb))
2154                 return 1;
2155
2156         return 0;
2157 }
2158
2159 /*
2160  * Helper function to trace a subtree tree block swap.
2161  *
2162  * The swap will happen in highest tree block, but there may be a lot of
2163  * tree blocks involved.
2164  *
2165  * For example:
2166  *  OO = Old tree blocks
2167  *  NN = New tree blocks allocated during balance
2168  *
2169  *           File tree (257)                  Reloc tree for 257
2170  * L2              OO                                NN
2171  *               /    \                            /    \
2172  * L1          OO      OO (a)                    OO      NN (a)
2173  *            / \     / \                       / \     / \
2174  * L0       OO   OO OO   OO                   OO   OO NN   NN
2175  *                  (b)  (c)                          (b)  (c)
2176  *
2177  * When calling qgroup_trace_extent_swap(), we will pass:
2178  * @src_eb = OO(a)
2179  * @dst_path = [ nodes[1] = NN(a), nodes[0] = NN(c) ]
2180  * @dst_level = 0
2181  * @root_level = 1
2182  *
2183  * In that case, qgroup_trace_extent_swap() will search from OO(a) to
2184  * reach OO(c), then mark both OO(c) and NN(c) as qgroup dirty.
2185  *
2186  * The main work of qgroup_trace_extent_swap() can be split into 3 parts:
2187  *
2188  * 1) Tree search from @src_eb
2189  *    It should acts as a simplified btrfs_search_slot().
2190  *    The key for search can be extracted from @dst_path->nodes[dst_level]
2191  *    (first key).
2192  *
2193  * 2) Mark the final tree blocks in @src_path and @dst_path qgroup dirty
2194  *    NOTE: In above case, OO(a) and NN(a) won't be marked qgroup dirty.
2195  *    They should be marked during previous (@dst_level = 1) iteration.
2196  *
2197  * 3) Mark file extents in leaves dirty
2198  *    We don't have good way to pick out new file extents only.
2199  *    So we still follow the old method by scanning all file extents in
2200  *    the leave.
2201  *
2202  * This function can free us from keeping two paths, thus later we only need
2203  * to care about how to iterate all new tree blocks in reloc tree.
2204  */
2205 static int qgroup_trace_extent_swap(struct btrfs_trans_handle* trans,
2206                                     struct extent_buffer *src_eb,
2207                                     struct btrfs_path *dst_path,
2208                                     int dst_level, int root_level,
2209                                     bool trace_leaf)
2210 {
2211         struct btrfs_key key;
2212         struct btrfs_path *src_path;
2213         struct btrfs_fs_info *fs_info = trans->fs_info;
2214         u32 nodesize = fs_info->nodesize;
2215         int cur_level = root_level;
2216         int ret;
2217
2218         BUG_ON(dst_level > root_level);
2219         /* Level mismatch */
2220         if (btrfs_header_level(src_eb) != root_level)
2221                 return -EINVAL;
2222
2223         src_path = btrfs_alloc_path();
2224         if (!src_path) {
2225                 ret = -ENOMEM;
2226                 goto out;
2227         }
2228
2229         if (dst_level)
2230                 btrfs_node_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
2231         else
2232                 btrfs_item_key_to_cpu(dst_path->nodes[dst_level], &key, 0);
2233
2234         /* For src_path */
2235         atomic_inc(&src_eb->refs);
2236         src_path->nodes[root_level] = src_eb;
2237         src_path->slots[root_level] = dst_path->slots[root_level];
2238         src_path->locks[root_level] = 0;
2239
2240         /* A simplified version of btrfs_search_slot() */
2241         while (cur_level >= dst_level) {
2242                 struct btrfs_key src_key;
2243                 struct btrfs_key dst_key;
2244
2245                 if (src_path->nodes[cur_level] == NULL) {
2246                         struct extent_buffer *eb;
2247                         int parent_slot;
2248
2249                         eb = src_path->nodes[cur_level + 1];
2250                         parent_slot = src_path->slots[cur_level + 1];
2251
2252                         eb = btrfs_read_node_slot(eb, parent_slot);
2253                         if (IS_ERR(eb)) {
2254                                 ret = PTR_ERR(eb);
2255                                 goto out;
2256                         }
2257
2258                         src_path->nodes[cur_level] = eb;
2259
2260                         btrfs_tree_read_lock(eb);
2261                         src_path->locks[cur_level] = BTRFS_READ_LOCK;
2262                 }
2263
2264                 src_path->slots[cur_level] = dst_path->slots[cur_level];
2265                 if (cur_level) {
2266                         btrfs_node_key_to_cpu(dst_path->nodes[cur_level],
2267                                         &dst_key, dst_path->slots[cur_level]);
2268                         btrfs_node_key_to_cpu(src_path->nodes[cur_level],
2269                                         &src_key, src_path->slots[cur_level]);
2270                 } else {
2271                         btrfs_item_key_to_cpu(dst_path->nodes[cur_level],
2272                                         &dst_key, dst_path->slots[cur_level]);
2273                         btrfs_item_key_to_cpu(src_path->nodes[cur_level],
2274                                         &src_key, src_path->slots[cur_level]);
2275                 }
2276                 /* Content mismatch, something went wrong */
2277                 if (btrfs_comp_cpu_keys(&dst_key, &src_key)) {
2278                         ret = -ENOENT;
2279                         goto out;
2280                 }
2281                 cur_level--;
2282         }
2283
2284         /*
2285          * Now both @dst_path and @src_path have been populated, record the tree
2286          * blocks for qgroup accounting.
2287          */
2288         ret = btrfs_qgroup_trace_extent(trans, src_path->nodes[dst_level]->start,
2289                                         nodesize);
2290         if (ret < 0)
2291                 goto out;
2292         ret = btrfs_qgroup_trace_extent(trans, dst_path->nodes[dst_level]->start,
2293                                         nodesize);
2294         if (ret < 0)
2295                 goto out;
2296
2297         /* Record leaf file extents */
2298         if (dst_level == 0 && trace_leaf) {
2299                 ret = btrfs_qgroup_trace_leaf_items(trans, src_path->nodes[0]);
2300                 if (ret < 0)
2301                         goto out;
2302                 ret = btrfs_qgroup_trace_leaf_items(trans, dst_path->nodes[0]);
2303         }
2304 out:
2305         btrfs_free_path(src_path);
2306         return ret;
2307 }
2308
2309 /*
2310  * Helper function to do recursive generation-aware depth-first search, to
2311  * locate all new tree blocks in a subtree of reloc tree.
2312  *
2313  * E.g. (OO = Old tree blocks, NN = New tree blocks, whose gen == last_snapshot)
2314  *         reloc tree
2315  * L2         NN (a)
2316  *          /    \
2317  * L1    OO        NN (b)
2318  *      /  \      /  \
2319  * L0  OO  OO    OO  NN
2320  *               (c) (d)
2321  * If we pass:
2322  * @dst_path = [ nodes[1] = NN(b), nodes[0] = NULL ],
2323  * @cur_level = 1
2324  * @root_level = 1
2325  *
2326  * We will iterate through tree blocks NN(b), NN(d) and info qgroup to trace
2327  * above tree blocks along with their counter parts in file tree.
2328  * While during search, old tree blocks OO(c) will be skipped as tree block swap
2329  * won't affect OO(c).
2330  */
2331 static int qgroup_trace_new_subtree_blocks(struct btrfs_trans_handle* trans,
2332                                            struct extent_buffer *src_eb,
2333                                            struct btrfs_path *dst_path,
2334                                            int cur_level, int root_level,
2335                                            u64 last_snapshot, bool trace_leaf)
2336 {
2337         struct btrfs_fs_info *fs_info = trans->fs_info;
2338         struct extent_buffer *eb;
2339         bool need_cleanup = false;
2340         int ret = 0;
2341         int i;
2342
2343         /* Level sanity check */
2344         if (cur_level < 0 || cur_level >= BTRFS_MAX_LEVEL - 1 ||
2345             root_level < 0 || root_level >= BTRFS_MAX_LEVEL - 1 ||
2346             root_level < cur_level) {
2347                 btrfs_err_rl(fs_info,
2348                         "%s: bad levels, cur_level=%d root_level=%d",
2349                         __func__, cur_level, root_level);
2350                 return -EUCLEAN;
2351         }
2352
2353         /* Read the tree block if needed */
2354         if (dst_path->nodes[cur_level] == NULL) {
2355                 int parent_slot;
2356                 u64 child_gen;
2357
2358                 /*
2359                  * dst_path->nodes[root_level] must be initialized before
2360                  * calling this function.
2361                  */
2362                 if (cur_level == root_level) {
2363                         btrfs_err_rl(fs_info,
2364         "%s: dst_path->nodes[%d] not initialized, root_level=%d cur_level=%d",
2365                                 __func__, root_level, root_level, cur_level);
2366                         return -EUCLEAN;
2367                 }
2368
2369                 /*
2370                  * We need to get child blockptr/gen from parent before we can
2371                  * read it.
2372                   */
2373                 eb = dst_path->nodes[cur_level + 1];
2374                 parent_slot = dst_path->slots[cur_level + 1];
2375                 child_gen = btrfs_node_ptr_generation(eb, parent_slot);
2376
2377                 /* This node is old, no need to trace */
2378                 if (child_gen < last_snapshot)
2379                         goto out;
2380
2381                 eb = btrfs_read_node_slot(eb, parent_slot);
2382                 if (IS_ERR(eb)) {
2383                         ret = PTR_ERR(eb);
2384                         goto out;
2385                 }
2386
2387                 dst_path->nodes[cur_level] = eb;
2388                 dst_path->slots[cur_level] = 0;
2389
2390                 btrfs_tree_read_lock(eb);
2391                 dst_path->locks[cur_level] = BTRFS_READ_LOCK;
2392                 need_cleanup = true;
2393         }
2394
2395         /* Now record this tree block and its counter part for qgroups */
2396         ret = qgroup_trace_extent_swap(trans, src_eb, dst_path, cur_level,
2397                                        root_level, trace_leaf);
2398         if (ret < 0)
2399                 goto cleanup;
2400
2401         eb = dst_path->nodes[cur_level];
2402
2403         if (cur_level > 0) {
2404                 /* Iterate all child tree blocks */
2405                 for (i = 0; i < btrfs_header_nritems(eb); i++) {
2406                         /* Skip old tree blocks as they won't be swapped */
2407                         if (btrfs_node_ptr_generation(eb, i) < last_snapshot)
2408                                 continue;
2409                         dst_path->slots[cur_level] = i;
2410
2411                         /* Recursive call (at most 7 times) */
2412                         ret = qgroup_trace_new_subtree_blocks(trans, src_eb,
2413                                         dst_path, cur_level - 1, root_level,
2414                                         last_snapshot, trace_leaf);
2415                         if (ret < 0)
2416                                 goto cleanup;
2417                 }
2418         }
2419
2420 cleanup:
2421         if (need_cleanup) {
2422                 /* Clean up */
2423                 btrfs_tree_unlock_rw(dst_path->nodes[cur_level],
2424                                      dst_path->locks[cur_level]);
2425                 free_extent_buffer(dst_path->nodes[cur_level]);
2426                 dst_path->nodes[cur_level] = NULL;
2427                 dst_path->slots[cur_level] = 0;
2428                 dst_path->locks[cur_level] = 0;
2429         }
2430 out:
2431         return ret;
2432 }
2433
2434 static int qgroup_trace_subtree_swap(struct btrfs_trans_handle *trans,
2435                                 struct extent_buffer *src_eb,
2436                                 struct extent_buffer *dst_eb,
2437                                 u64 last_snapshot, bool trace_leaf)
2438 {
2439         struct btrfs_fs_info *fs_info = trans->fs_info;
2440         struct btrfs_path *dst_path = NULL;
2441         int level;
2442         int ret;
2443
2444         if (!btrfs_qgroup_full_accounting(fs_info))
2445                 return 0;
2446
2447         /* Wrong parameter order */
2448         if (btrfs_header_generation(src_eb) > btrfs_header_generation(dst_eb)) {
2449                 btrfs_err_rl(fs_info,
2450                 "%s: bad parameter order, src_gen=%llu dst_gen=%llu", __func__,
2451                              btrfs_header_generation(src_eb),
2452                              btrfs_header_generation(dst_eb));
2453                 return -EUCLEAN;
2454         }
2455
2456         if (!extent_buffer_uptodate(src_eb) || !extent_buffer_uptodate(dst_eb)) {
2457                 ret = -EIO;
2458                 goto out;
2459         }
2460
2461         level = btrfs_header_level(dst_eb);
2462         dst_path = btrfs_alloc_path();
2463         if (!dst_path) {
2464                 ret = -ENOMEM;
2465                 goto out;
2466         }
2467         /* For dst_path */
2468         atomic_inc(&dst_eb->refs);
2469         dst_path->nodes[level] = dst_eb;
2470         dst_path->slots[level] = 0;
2471         dst_path->locks[level] = 0;
2472
2473         /* Do the generation aware breadth-first search */
2474         ret = qgroup_trace_new_subtree_blocks(trans, src_eb, dst_path, level,
2475                                               level, last_snapshot, trace_leaf);
2476         if (ret < 0)
2477                 goto out;
2478         ret = 0;
2479
2480 out:
2481         btrfs_free_path(dst_path);
2482         if (ret < 0)
2483                 qgroup_mark_inconsistent(fs_info);
2484         return ret;
2485 }
2486
2487 /*
2488  * Inform qgroup to trace a whole subtree, including all its child tree
2489  * blocks and data.
2490  * The root tree block is specified by @root_eb.
2491  *
2492  * Normally used by relocation(tree block swap) and subvolume deletion.
2493  *
2494  * Return 0 for success
2495  * Return <0 for error(ENOMEM or tree search error)
2496  */
2497 int btrfs_qgroup_trace_subtree(struct btrfs_trans_handle *trans,
2498                                struct extent_buffer *root_eb,
2499                                u64 root_gen, int root_level)
2500 {
2501         struct btrfs_fs_info *fs_info = trans->fs_info;
2502         int ret = 0;
2503         int level;
2504         u8 drop_subptree_thres;
2505         struct extent_buffer *eb = root_eb;
2506         struct btrfs_path *path = NULL;
2507
2508         ASSERT(0 <= root_level && root_level < BTRFS_MAX_LEVEL);
2509         ASSERT(root_eb != NULL);
2510
2511         if (!btrfs_qgroup_full_accounting(fs_info))
2512                 return 0;
2513
2514         spin_lock(&fs_info->qgroup_lock);
2515         drop_subptree_thres = fs_info->qgroup_drop_subtree_thres;
2516         spin_unlock(&fs_info->qgroup_lock);
2517
2518         /*
2519          * This function only gets called for snapshot drop, if we hit a high
2520          * node here, it means we are going to change ownership for quite a lot
2521          * of extents, which will greatly slow down btrfs_commit_transaction().
2522          *
2523          * So here if we find a high tree here, we just skip the accounting and
2524          * mark qgroup inconsistent.
2525          */
2526         if (root_level >= drop_subptree_thres) {
2527                 qgroup_mark_inconsistent(fs_info);
2528                 return 0;
2529         }
2530
2531         if (!extent_buffer_uptodate(root_eb)) {
2532                 struct btrfs_tree_parent_check check = {
2533                         .has_first_key = false,
2534                         .transid = root_gen,
2535                         .level = root_level
2536                 };
2537
2538                 ret = btrfs_read_extent_buffer(root_eb, &check);
2539                 if (ret)
2540                         goto out;
2541         }
2542
2543         if (root_level == 0) {
2544                 ret = btrfs_qgroup_trace_leaf_items(trans, root_eb);
2545                 goto out;
2546         }
2547
2548         path = btrfs_alloc_path();
2549         if (!path)
2550                 return -ENOMEM;
2551
2552         /*
2553          * Walk down the tree.  Missing extent blocks are filled in as
2554          * we go. Metadata is accounted every time we read a new
2555          * extent block.
2556          *
2557          * When we reach a leaf, we account for file extent items in it,
2558          * walk back up the tree (adjusting slot pointers as we go)
2559          * and restart the search process.
2560          */
2561         atomic_inc(&root_eb->refs);     /* For path */
2562         path->nodes[root_level] = root_eb;
2563         path->slots[root_level] = 0;
2564         path->locks[root_level] = 0; /* so release_path doesn't try to unlock */
2565 walk_down:
2566         level = root_level;
2567         while (level >= 0) {
2568                 if (path->nodes[level] == NULL) {
2569                         int parent_slot;
2570                         u64 child_bytenr;
2571
2572                         /*
2573                          * We need to get child blockptr from parent before we
2574                          * can read it.
2575                           */
2576                         eb = path->nodes[level + 1];
2577                         parent_slot = path->slots[level + 1];
2578                         child_bytenr = btrfs_node_blockptr(eb, parent_slot);
2579
2580                         eb = btrfs_read_node_slot(eb, parent_slot);
2581                         if (IS_ERR(eb)) {
2582                                 ret = PTR_ERR(eb);
2583                                 goto out;
2584                         }
2585
2586                         path->nodes[level] = eb;
2587                         path->slots[level] = 0;
2588
2589                         btrfs_tree_read_lock(eb);
2590                         path->locks[level] = BTRFS_READ_LOCK;
2591
2592                         ret = btrfs_qgroup_trace_extent(trans, child_bytenr,
2593                                                         fs_info->nodesize);
2594                         if (ret)
2595                                 goto out;
2596                 }
2597
2598                 if (level == 0) {
2599                         ret = btrfs_qgroup_trace_leaf_items(trans,
2600                                                             path->nodes[level]);
2601                         if (ret)
2602                                 goto out;
2603
2604                         /* Nonzero return here means we completed our search */
2605                         ret = adjust_slots_upwards(path, root_level);
2606                         if (ret)
2607                                 break;
2608
2609                         /* Restart search with new slots */
2610                         goto walk_down;
2611                 }
2612
2613                 level--;
2614         }
2615
2616         ret = 0;
2617 out:
2618         btrfs_free_path(path);
2619
2620         return ret;
2621 }
2622
2623 static void qgroup_iterator_nested_add(struct list_head *head, struct btrfs_qgroup *qgroup)
2624 {
2625         if (!list_empty(&qgroup->nested_iterator))
2626                 return;
2627
2628         list_add_tail(&qgroup->nested_iterator, head);
2629 }
2630
2631 static void qgroup_iterator_nested_clean(struct list_head *head)
2632 {
2633         while (!list_empty(head)) {
2634                 struct btrfs_qgroup *qgroup;
2635
2636                 qgroup = list_first_entry(head, struct btrfs_qgroup, nested_iterator);
2637                 list_del_init(&qgroup->nested_iterator);
2638         }
2639 }
2640
2641 #define UPDATE_NEW      0
2642 #define UPDATE_OLD      1
2643 /*
2644  * Walk all of the roots that points to the bytenr and adjust their refcnts.
2645  */
2646 static void qgroup_update_refcnt(struct btrfs_fs_info *fs_info,
2647                                  struct ulist *roots, struct list_head *qgroups,
2648                                  u64 seq, int update_old)
2649 {
2650         struct ulist_node *unode;
2651         struct ulist_iterator uiter;
2652         struct btrfs_qgroup *qg;
2653
2654         if (!roots)
2655                 return;
2656         ULIST_ITER_INIT(&uiter);
2657         while ((unode = ulist_next(roots, &uiter))) {
2658                 LIST_HEAD(tmp);
2659
2660                 qg = find_qgroup_rb(fs_info, unode->val);
2661                 if (!qg)
2662                         continue;
2663
2664                 qgroup_iterator_nested_add(qgroups, qg);
2665                 qgroup_iterator_add(&tmp, qg);
2666                 list_for_each_entry(qg, &tmp, iterator) {
2667                         struct btrfs_qgroup_list *glist;
2668
2669                         if (update_old)
2670                                 btrfs_qgroup_update_old_refcnt(qg, seq, 1);
2671                         else
2672                                 btrfs_qgroup_update_new_refcnt(qg, seq, 1);
2673
2674                         list_for_each_entry(glist, &qg->groups, next_group) {
2675                                 qgroup_iterator_nested_add(qgroups, glist->group);
2676                                 qgroup_iterator_add(&tmp, glist->group);
2677                         }
2678                 }
2679                 qgroup_iterator_clean(&tmp);
2680         }
2681 }
2682
2683 /*
2684  * Update qgroup rfer/excl counters.
2685  * Rfer update is easy, codes can explain themselves.
2686  *
2687  * Excl update is tricky, the update is split into 2 parts.
2688  * Part 1: Possible exclusive <-> sharing detect:
2689  *      |       A       |       !A      |
2690  *  -------------------------------------
2691  *  B   |       *       |       -       |
2692  *  -------------------------------------
2693  *  !B  |       +       |       **      |
2694  *  -------------------------------------
2695  *
2696  * Conditions:
2697  * A:   cur_old_roots < nr_old_roots    (not exclusive before)
2698  * !A:  cur_old_roots == nr_old_roots   (possible exclusive before)
2699  * B:   cur_new_roots < nr_new_roots    (not exclusive now)
2700  * !B:  cur_new_roots == nr_new_roots   (possible exclusive now)
2701  *
2702  * Results:
2703  * +: Possible sharing -> exclusive     -: Possible exclusive -> sharing
2704  * *: Definitely not changed.           **: Possible unchanged.
2705  *
2706  * For !A and !B condition, the exception is cur_old/new_roots == 0 case.
2707  *
2708  * To make the logic clear, we first use condition A and B to split
2709  * combination into 4 results.
2710  *
2711  * Then, for result "+" and "-", check old/new_roots == 0 case, as in them
2712  * only on variant maybe 0.
2713  *
2714  * Lastly, check result **, since there are 2 variants maybe 0, split them
2715  * again(2x2).
2716  * But this time we don't need to consider other things, the codes and logic
2717  * is easy to understand now.
2718  */
2719 static void qgroup_update_counters(struct btrfs_fs_info *fs_info,
2720                                    struct list_head *qgroups, u64 nr_old_roots,
2721                                    u64 nr_new_roots, u64 num_bytes, u64 seq)
2722 {
2723         struct btrfs_qgroup *qg;
2724
2725         list_for_each_entry(qg, qgroups, nested_iterator) {
2726                 u64 cur_new_count, cur_old_count;
2727                 bool dirty = false;
2728
2729                 cur_old_count = btrfs_qgroup_get_old_refcnt(qg, seq);
2730                 cur_new_count = btrfs_qgroup_get_new_refcnt(qg, seq);
2731
2732                 trace_qgroup_update_counters(fs_info, qg, cur_old_count,
2733                                              cur_new_count);
2734
2735                 /* Rfer update part */
2736                 if (cur_old_count == 0 && cur_new_count > 0) {
2737                         qg->rfer += num_bytes;
2738                         qg->rfer_cmpr += num_bytes;
2739                         dirty = true;
2740                 }
2741                 if (cur_old_count > 0 && cur_new_count == 0) {
2742                         qg->rfer -= num_bytes;
2743                         qg->rfer_cmpr -= num_bytes;
2744                         dirty = true;
2745                 }
2746
2747                 /* Excl update part */
2748                 /* Exclusive/none -> shared case */
2749                 if (cur_old_count == nr_old_roots &&
2750                     cur_new_count < nr_new_roots) {
2751                         /* Exclusive -> shared */
2752                         if (cur_old_count != 0) {
2753                                 qg->excl -= num_bytes;
2754                                 qg->excl_cmpr -= num_bytes;
2755                                 dirty = true;
2756                         }
2757                 }
2758
2759                 /* Shared -> exclusive/none case */
2760                 if (cur_old_count < nr_old_roots &&
2761                     cur_new_count == nr_new_roots) {
2762                         /* Shared->exclusive */
2763                         if (cur_new_count != 0) {
2764                                 qg->excl += num_bytes;
2765                                 qg->excl_cmpr += num_bytes;
2766                                 dirty = true;
2767                         }
2768                 }
2769
2770                 /* Exclusive/none -> exclusive/none case */
2771                 if (cur_old_count == nr_old_roots &&
2772                     cur_new_count == nr_new_roots) {
2773                         if (cur_old_count == 0) {
2774                                 /* None -> exclusive/none */
2775
2776                                 if (cur_new_count != 0) {
2777                                         /* None -> exclusive */
2778                                         qg->excl += num_bytes;
2779                                         qg->excl_cmpr += num_bytes;
2780                                         dirty = true;
2781                                 }
2782                                 /* None -> none, nothing changed */
2783                         } else {
2784                                 /* Exclusive -> exclusive/none */
2785
2786                                 if (cur_new_count == 0) {
2787                                         /* Exclusive -> none */
2788                                         qg->excl -= num_bytes;
2789                                         qg->excl_cmpr -= num_bytes;
2790                                         dirty = true;
2791                                 }
2792                                 /* Exclusive -> exclusive, nothing changed */
2793                         }
2794                 }
2795
2796                 if (dirty)
2797                         qgroup_dirty(fs_info, qg);
2798         }
2799 }
2800
2801 /*
2802  * Check if the @roots potentially is a list of fs tree roots
2803  *
2804  * Return 0 for definitely not a fs/subvol tree roots ulist
2805  * Return 1 for possible fs/subvol tree roots in the list (considering an empty
2806  *          one as well)
2807  */
2808 static int maybe_fs_roots(struct ulist *roots)
2809 {
2810         struct ulist_node *unode;
2811         struct ulist_iterator uiter;
2812
2813         /* Empty one, still possible for fs roots */
2814         if (!roots || roots->nnodes == 0)
2815                 return 1;
2816
2817         ULIST_ITER_INIT(&uiter);
2818         unode = ulist_next(roots, &uiter);
2819         if (!unode)
2820                 return 1;
2821
2822         /*
2823          * If it contains fs tree roots, then it must belong to fs/subvol
2824          * trees.
2825          * If it contains a non-fs tree, it won't be shared with fs/subvol trees.
2826          */
2827         return is_fstree(unode->val);
2828 }
2829
2830 int btrfs_qgroup_account_extent(struct btrfs_trans_handle *trans, u64 bytenr,
2831                                 u64 num_bytes, struct ulist *old_roots,
2832                                 struct ulist *new_roots)
2833 {
2834         struct btrfs_fs_info *fs_info = trans->fs_info;
2835         LIST_HEAD(qgroups);
2836         u64 seq;
2837         u64 nr_new_roots = 0;
2838         u64 nr_old_roots = 0;
2839         int ret = 0;
2840
2841         /*
2842          * If quotas get disabled meanwhile, the resources need to be freed and
2843          * we can't just exit here.
2844          */
2845         if (!btrfs_qgroup_full_accounting(fs_info) ||
2846             fs_info->qgroup_flags & BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING)
2847                 goto out_free;
2848
2849         if (new_roots) {
2850                 if (!maybe_fs_roots(new_roots))
2851                         goto out_free;
2852                 nr_new_roots = new_roots->nnodes;
2853         }
2854         if (old_roots) {
2855                 if (!maybe_fs_roots(old_roots))
2856                         goto out_free;
2857                 nr_old_roots = old_roots->nnodes;
2858         }
2859
2860         /* Quick exit, either not fs tree roots, or won't affect any qgroup */
2861         if (nr_old_roots == 0 && nr_new_roots == 0)
2862                 goto out_free;
2863
2864         trace_btrfs_qgroup_account_extent(fs_info, trans->transid, bytenr,
2865                                         num_bytes, nr_old_roots, nr_new_roots);
2866
2867         mutex_lock(&fs_info->qgroup_rescan_lock);
2868         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
2869                 if (fs_info->qgroup_rescan_progress.objectid <= bytenr) {
2870                         mutex_unlock(&fs_info->qgroup_rescan_lock);
2871                         ret = 0;
2872                         goto out_free;
2873                 }
2874         }
2875         mutex_unlock(&fs_info->qgroup_rescan_lock);
2876
2877         spin_lock(&fs_info->qgroup_lock);
2878         seq = fs_info->qgroup_seq;
2879
2880         /* Update old refcnts using old_roots */
2881         qgroup_update_refcnt(fs_info, old_roots, &qgroups, seq, UPDATE_OLD);
2882
2883         /* Update new refcnts using new_roots */
2884         qgroup_update_refcnt(fs_info, new_roots, &qgroups, seq, UPDATE_NEW);
2885
2886         qgroup_update_counters(fs_info, &qgroups, nr_old_roots, nr_new_roots,
2887                                num_bytes, seq);
2888
2889         /*
2890          * We're done using the iterator, release all its qgroups while holding
2891          * fs_info->qgroup_lock so that we don't race with btrfs_remove_qgroup()
2892          * and trigger use-after-free accesses to qgroups.
2893          */
2894         qgroup_iterator_nested_clean(&qgroups);
2895
2896         /*
2897          * Bump qgroup_seq to avoid seq overlap
2898          */
2899         fs_info->qgroup_seq += max(nr_old_roots, nr_new_roots) + 1;
2900         spin_unlock(&fs_info->qgroup_lock);
2901 out_free:
2902         ulist_free(old_roots);
2903         ulist_free(new_roots);
2904         return ret;
2905 }
2906
2907 int btrfs_qgroup_account_extents(struct btrfs_trans_handle *trans)
2908 {
2909         struct btrfs_fs_info *fs_info = trans->fs_info;
2910         struct btrfs_qgroup_extent_record *record;
2911         struct btrfs_delayed_ref_root *delayed_refs;
2912         struct ulist *new_roots = NULL;
2913         struct rb_node *node;
2914         u64 num_dirty_extents = 0;
2915         u64 qgroup_to_skip;
2916         int ret = 0;
2917
2918         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
2919                 return 0;
2920
2921         delayed_refs = &trans->transaction->delayed_refs;
2922         qgroup_to_skip = delayed_refs->qgroup_to_skip;
2923         while ((node = rb_first(&delayed_refs->dirty_extent_root))) {
2924                 record = rb_entry(node, struct btrfs_qgroup_extent_record,
2925                                   node);
2926
2927                 num_dirty_extents++;
2928                 trace_btrfs_qgroup_account_extents(fs_info, record);
2929
2930                 if (!ret && !(fs_info->qgroup_flags &
2931                               BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING)) {
2932                         struct btrfs_backref_walk_ctx ctx = { 0 };
2933
2934                         ctx.bytenr = record->bytenr;
2935                         ctx.fs_info = fs_info;
2936
2937                         /*
2938                          * Old roots should be searched when inserting qgroup
2939                          * extent record.
2940                          *
2941                          * But for INCONSISTENT (NO_ACCOUNTING) -> rescan case,
2942                          * we may have some record inserted during
2943                          * NO_ACCOUNTING (thus no old_roots populated), but
2944                          * later we start rescan, which clears NO_ACCOUNTING,
2945                          * leaving some inserted records without old_roots
2946                          * populated.
2947                          *
2948                          * Those cases are rare and should not cause too much
2949                          * time spent during commit_transaction().
2950                          */
2951                         if (!record->old_roots) {
2952                                 /* Search commit root to find old_roots */
2953                                 ret = btrfs_find_all_roots(&ctx, false);
2954                                 if (ret < 0)
2955                                         goto cleanup;
2956                                 record->old_roots = ctx.roots;
2957                                 ctx.roots = NULL;
2958                         }
2959
2960                         /*
2961                          * Use BTRFS_SEQ_LAST as time_seq to do special search,
2962                          * which doesn't lock tree or delayed_refs and search
2963                          * current root. It's safe inside commit_transaction().
2964                          */
2965                         ctx.trans = trans;
2966                         ctx.time_seq = BTRFS_SEQ_LAST;
2967                         ret = btrfs_find_all_roots(&ctx, false);
2968                         if (ret < 0)
2969                                 goto cleanup;
2970                         new_roots = ctx.roots;
2971                         if (qgroup_to_skip) {
2972                                 ulist_del(new_roots, qgroup_to_skip, 0);
2973                                 ulist_del(record->old_roots, qgroup_to_skip,
2974                                           0);
2975                         }
2976                         ret = btrfs_qgroup_account_extent(trans, record->bytenr,
2977                                                           record->num_bytes,
2978                                                           record->old_roots,
2979                                                           new_roots);
2980                         record->old_roots = NULL;
2981                         new_roots = NULL;
2982                 }
2983                 /* Free the reserved data space */
2984                 btrfs_qgroup_free_refroot(fs_info,
2985                                 record->data_rsv_refroot,
2986                                 record->data_rsv,
2987                                 BTRFS_QGROUP_RSV_DATA);
2988 cleanup:
2989                 ulist_free(record->old_roots);
2990                 ulist_free(new_roots);
2991                 new_roots = NULL;
2992                 rb_erase(node, &delayed_refs->dirty_extent_root);
2993                 kfree(record);
2994
2995         }
2996         trace_qgroup_num_dirty_extents(fs_info, trans->transid,
2997                                        num_dirty_extents);
2998         return ret;
2999 }
3000
3001 /*
3002  * Writes all changed qgroups to disk.
3003  * Called by the transaction commit path and the qgroup assign ioctl.
3004  */
3005 int btrfs_run_qgroups(struct btrfs_trans_handle *trans)
3006 {
3007         struct btrfs_fs_info *fs_info = trans->fs_info;
3008         int ret = 0;
3009
3010         /*
3011          * In case we are called from the qgroup assign ioctl, assert that we
3012          * are holding the qgroup_ioctl_lock, otherwise we can race with a quota
3013          * disable operation (ioctl) and access a freed quota root.
3014          */
3015         if (trans->transaction->state != TRANS_STATE_COMMIT_DOING)
3016                 lockdep_assert_held(&fs_info->qgroup_ioctl_lock);
3017
3018         if (!fs_info->quota_root)
3019                 return ret;
3020
3021         spin_lock(&fs_info->qgroup_lock);
3022         while (!list_empty(&fs_info->dirty_qgroups)) {
3023                 struct btrfs_qgroup *qgroup;
3024                 qgroup = list_first_entry(&fs_info->dirty_qgroups,
3025                                           struct btrfs_qgroup, dirty);
3026                 list_del_init(&qgroup->dirty);
3027                 spin_unlock(&fs_info->qgroup_lock);
3028                 ret = update_qgroup_info_item(trans, qgroup);
3029                 if (ret)
3030                         qgroup_mark_inconsistent(fs_info);
3031                 ret = update_qgroup_limit_item(trans, qgroup);
3032                 if (ret)
3033                         qgroup_mark_inconsistent(fs_info);
3034                 spin_lock(&fs_info->qgroup_lock);
3035         }
3036         if (btrfs_qgroup_enabled(fs_info))
3037                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_ON;
3038         else
3039                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_ON;
3040         spin_unlock(&fs_info->qgroup_lock);
3041
3042         ret = update_qgroup_status_item(trans);
3043         if (ret)
3044                 qgroup_mark_inconsistent(fs_info);
3045
3046         return ret;
3047 }
3048
3049 int btrfs_qgroup_check_inherit(struct btrfs_fs_info *fs_info,
3050                                struct btrfs_qgroup_inherit *inherit,
3051                                size_t size)
3052 {
3053         if (inherit->flags & ~BTRFS_QGROUP_INHERIT_FLAGS_SUPP)
3054                 return -EOPNOTSUPP;
3055         if (size < sizeof(*inherit) || size > PAGE_SIZE)
3056                 return -EINVAL;
3057
3058         /*
3059          * In the past we allowed btrfs_qgroup_inherit to specify to copy
3060          * rfer/excl numbers directly from other qgroups.  This behavior has
3061          * been disabled in userspace for a very long time, but here we should
3062          * also disable it in kernel, as this behavior is known to mark qgroup
3063          * inconsistent, and a rescan would wipe out the changes anyway.
3064          *
3065          * Reject any btrfs_qgroup_inherit with num_ref_copies or num_excl_copies.
3066          */
3067         if (inherit->num_ref_copies > 0 || inherit->num_excl_copies > 0)
3068                 return -EINVAL;
3069
3070         if (inherit->num_qgroups > PAGE_SIZE)
3071                 return -EINVAL;
3072
3073         if (size != struct_size(inherit, qgroups, inherit->num_qgroups))
3074                 return -EINVAL;
3075
3076         /*
3077          * Now check all the remaining qgroups, they should all:
3078          *
3079          * - Exist
3080          * - Be higher level qgroups.
3081          */
3082         for (int i = 0; i < inherit->num_qgroups; i++) {
3083                 struct btrfs_qgroup *qgroup;
3084                 u64 qgroupid = inherit->qgroups[i];
3085
3086                 if (btrfs_qgroup_level(qgroupid) == 0)
3087                         return -EINVAL;
3088
3089                 spin_lock(&fs_info->qgroup_lock);
3090                 qgroup = find_qgroup_rb(fs_info, qgroupid);
3091                 if (!qgroup) {
3092                         spin_unlock(&fs_info->qgroup_lock);
3093                         return -ENOENT;
3094                 }
3095                 spin_unlock(&fs_info->qgroup_lock);
3096         }
3097         return 0;
3098 }
3099
3100 static int qgroup_auto_inherit(struct btrfs_fs_info *fs_info,
3101                                u64 inode_rootid,
3102                                struct btrfs_qgroup_inherit **inherit)
3103 {
3104         int i = 0;
3105         u64 num_qgroups = 0;
3106         struct btrfs_qgroup *inode_qg;
3107         struct btrfs_qgroup_list *qg_list;
3108         struct btrfs_qgroup_inherit *res;
3109         size_t struct_sz;
3110         u64 *qgids;
3111
3112         if (*inherit)
3113                 return -EEXIST;
3114
3115         inode_qg = find_qgroup_rb(fs_info, inode_rootid);
3116         if (!inode_qg)
3117                 return -ENOENT;
3118
3119         num_qgroups = list_count_nodes(&inode_qg->groups);
3120
3121         if (!num_qgroups)
3122                 return 0;
3123
3124         struct_sz = struct_size(res, qgroups, num_qgroups);
3125         if (struct_sz == SIZE_MAX)
3126                 return -ERANGE;
3127
3128         res = kzalloc(struct_sz, GFP_NOFS);
3129         if (!res)
3130                 return -ENOMEM;
3131         res->num_qgroups = num_qgroups;
3132         qgids = res->qgroups;
3133
3134         list_for_each_entry(qg_list, &inode_qg->groups, next_group)
3135                 qgids[i] = qg_list->group->qgroupid;
3136
3137         *inherit = res;
3138         return 0;
3139 }
3140
3141 /*
3142  * Check if we can skip rescan when inheriting qgroups.  If @src has a single
3143  * @parent, and that @parent is owning all its bytes exclusively, we can skip
3144  * the full rescan, by just adding nodesize to the @parent's excl/rfer.
3145  *
3146  * Return <0 for fatal errors (like srcid/parentid has no qgroup).
3147  * Return 0 if a quick inherit is done.
3148  * Return >0 if a quick inherit is not possible, and a full rescan is needed.
3149  */
3150 static int qgroup_snapshot_quick_inherit(struct btrfs_fs_info *fs_info,
3151                                          u64 srcid, u64 parentid)
3152 {
3153         struct btrfs_qgroup *src;
3154         struct btrfs_qgroup *parent;
3155         struct btrfs_qgroup_list *list;
3156         int nr_parents = 0;
3157
3158         src = find_qgroup_rb(fs_info, srcid);
3159         if (!src)
3160                 return -ENOENT;
3161         parent = find_qgroup_rb(fs_info, parentid);
3162         if (!parent)
3163                 return -ENOENT;
3164
3165         /*
3166          * Source has no parent qgroup, but our new qgroup would have one.
3167          * Qgroup numbers would become inconsistent.
3168          */
3169         if (list_empty(&src->groups))
3170                 return 1;
3171
3172         list_for_each_entry(list, &src->groups, next_group) {
3173                 /* The parent is not the same, quick update is not possible. */
3174                 if (list->group->qgroupid != parentid)
3175                         return 1;
3176                 nr_parents++;
3177                 /*
3178                  * More than one parent qgroup, we can't be sure about accounting
3179                  * consistency.
3180                  */
3181                 if (nr_parents > 1)
3182                         return 1;
3183         }
3184
3185         /*
3186          * The parent is not exclusively owning all its bytes.  We're not sure
3187          * if the source has any bytes not fully owned by the parent.
3188          */
3189         if (parent->excl != parent->rfer)
3190                 return 1;
3191
3192         parent->excl += fs_info->nodesize;
3193         parent->rfer += fs_info->nodesize;
3194         return 0;
3195 }
3196
3197 /*
3198  * Copy the accounting information between qgroups. This is necessary
3199  * when a snapshot or a subvolume is created. Throwing an error will
3200  * cause a transaction abort so we take extra care here to only error
3201  * when a readonly fs is a reasonable outcome.
3202  */
3203 int btrfs_qgroup_inherit(struct btrfs_trans_handle *trans, u64 srcid,
3204                          u64 objectid, u64 inode_rootid,
3205                          struct btrfs_qgroup_inherit *inherit)
3206 {
3207         int ret = 0;
3208         int i;
3209         u64 *i_qgroups;
3210         bool committing = false;
3211         struct btrfs_fs_info *fs_info = trans->fs_info;
3212         struct btrfs_root *quota_root;
3213         struct btrfs_qgroup *srcgroup;
3214         struct btrfs_qgroup *dstgroup;
3215         struct btrfs_qgroup *prealloc;
3216         struct btrfs_qgroup_list **qlist_prealloc = NULL;
3217         bool free_inherit = false;
3218         bool need_rescan = false;
3219         u32 level_size = 0;
3220         u64 nums;
3221
3222         prealloc = kzalloc(sizeof(*prealloc), GFP_NOFS);
3223         if (!prealloc)
3224                 return -ENOMEM;
3225
3226         /*
3227          * There are only two callers of this function.
3228          *
3229          * One in create_subvol() in the ioctl context, which needs to hold
3230          * the qgroup_ioctl_lock.
3231          *
3232          * The other one in create_pending_snapshot() where no other qgroup
3233          * code can modify the fs as they all need to either start a new trans
3234          * or hold a trans handler, thus we don't need to hold
3235          * qgroup_ioctl_lock.
3236          * This would avoid long and complex lock chain and make lockdep happy.
3237          */
3238         spin_lock(&fs_info->trans_lock);
3239         if (trans->transaction->state == TRANS_STATE_COMMIT_DOING)
3240                 committing = true;
3241         spin_unlock(&fs_info->trans_lock);
3242
3243         if (!committing)
3244                 mutex_lock(&fs_info->qgroup_ioctl_lock);
3245         if (!btrfs_qgroup_enabled(fs_info))
3246                 goto out;
3247
3248         quota_root = fs_info->quota_root;
3249         if (!quota_root) {
3250                 ret = -EINVAL;
3251                 goto out;
3252         }
3253
3254         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE && !inherit) {
3255                 ret = qgroup_auto_inherit(fs_info, inode_rootid, &inherit);
3256                 if (ret)
3257                         goto out;
3258                 free_inherit = true;
3259         }
3260
3261         if (inherit) {
3262                 i_qgroups = (u64 *)(inherit + 1);
3263                 nums = inherit->num_qgroups + 2 * inherit->num_ref_copies +
3264                        2 * inherit->num_excl_copies;
3265                 for (i = 0; i < nums; ++i) {
3266                         srcgroup = find_qgroup_rb(fs_info, *i_qgroups);
3267
3268                         /*
3269                          * Zero out invalid groups so we can ignore
3270                          * them later.
3271                          */
3272                         if (!srcgroup ||
3273                             ((srcgroup->qgroupid >> 48) <= (objectid >> 48)))
3274                                 *i_qgroups = 0ULL;
3275
3276                         ++i_qgroups;
3277                 }
3278         }
3279
3280         /*
3281          * create a tracking group for the subvol itself
3282          */
3283         ret = add_qgroup_item(trans, quota_root, objectid);
3284         if (ret)
3285                 goto out;
3286
3287         /*
3288          * add qgroup to all inherited groups
3289          */
3290         if (inherit) {
3291                 i_qgroups = (u64 *)(inherit + 1);
3292                 for (i = 0; i < inherit->num_qgroups; ++i, ++i_qgroups) {
3293                         if (*i_qgroups == 0)
3294                                 continue;
3295                         ret = add_qgroup_relation_item(trans, objectid,
3296                                                        *i_qgroups);
3297                         if (ret && ret != -EEXIST)
3298                                 goto out;
3299                         ret = add_qgroup_relation_item(trans, *i_qgroups,
3300                                                        objectid);
3301                         if (ret && ret != -EEXIST)
3302                                 goto out;
3303                 }
3304                 ret = 0;
3305
3306                 qlist_prealloc = kcalloc(inherit->num_qgroups,
3307                                          sizeof(struct btrfs_qgroup_list *),
3308                                          GFP_NOFS);
3309                 if (!qlist_prealloc) {
3310                         ret = -ENOMEM;
3311                         goto out;
3312                 }
3313                 for (int i = 0; i < inherit->num_qgroups; i++) {
3314                         qlist_prealloc[i] = kzalloc(sizeof(struct btrfs_qgroup_list),
3315                                                     GFP_NOFS);
3316                         if (!qlist_prealloc[i]) {
3317                                 ret = -ENOMEM;
3318                                 goto out;
3319                         }
3320                 }
3321         }
3322
3323         spin_lock(&fs_info->qgroup_lock);
3324
3325         dstgroup = add_qgroup_rb(fs_info, prealloc, objectid);
3326         prealloc = NULL;
3327
3328         if (inherit && inherit->flags & BTRFS_QGROUP_INHERIT_SET_LIMITS) {
3329                 dstgroup->lim_flags = inherit->lim.flags;
3330                 dstgroup->max_rfer = inherit->lim.max_rfer;
3331                 dstgroup->max_excl = inherit->lim.max_excl;
3332                 dstgroup->rsv_rfer = inherit->lim.rsv_rfer;
3333                 dstgroup->rsv_excl = inherit->lim.rsv_excl;
3334
3335                 qgroup_dirty(fs_info, dstgroup);
3336         }
3337
3338         if (srcid && btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL) {
3339                 srcgroup = find_qgroup_rb(fs_info, srcid);
3340                 if (!srcgroup)
3341                         goto unlock;
3342
3343                 /*
3344                  * We call inherit after we clone the root in order to make sure
3345                  * our counts don't go crazy, so at this point the only
3346                  * difference between the two roots should be the root node.
3347                  */
3348                 level_size = fs_info->nodesize;
3349                 dstgroup->rfer = srcgroup->rfer;
3350                 dstgroup->rfer_cmpr = srcgroup->rfer_cmpr;
3351                 dstgroup->excl = level_size;
3352                 dstgroup->excl_cmpr = level_size;
3353                 srcgroup->excl = level_size;
3354                 srcgroup->excl_cmpr = level_size;
3355
3356                 /* inherit the limit info */
3357                 dstgroup->lim_flags = srcgroup->lim_flags;
3358                 dstgroup->max_rfer = srcgroup->max_rfer;
3359                 dstgroup->max_excl = srcgroup->max_excl;
3360                 dstgroup->rsv_rfer = srcgroup->rsv_rfer;
3361                 dstgroup->rsv_excl = srcgroup->rsv_excl;
3362
3363                 qgroup_dirty(fs_info, dstgroup);
3364                 qgroup_dirty(fs_info, srcgroup);
3365
3366                 /*
3367                  * If the source qgroup has parent but the new one doesn't,
3368                  * we need a full rescan.
3369                  */
3370                 if (!inherit && !list_empty(&srcgroup->groups))
3371                         need_rescan = true;
3372         }
3373
3374         if (!inherit)
3375                 goto unlock;
3376
3377         i_qgroups = (u64 *)(inherit + 1);
3378         for (i = 0; i < inherit->num_qgroups; ++i) {
3379                 if (*i_qgroups) {
3380                         ret = add_relation_rb(fs_info, qlist_prealloc[i], objectid,
3381                                               *i_qgroups);
3382                         qlist_prealloc[i] = NULL;
3383                         if (ret)
3384                                 goto unlock;
3385                 }
3386                 if (srcid) {
3387                         /* Check if we can do a quick inherit. */
3388                         ret = qgroup_snapshot_quick_inherit(fs_info, srcid, *i_qgroups);
3389                         if (ret < 0)
3390                                 goto unlock;
3391                         if (ret > 0)
3392                                 need_rescan = true;
3393                         ret = 0;
3394                 }
3395                 ++i_qgroups;
3396         }
3397
3398         for (i = 0; i <  inherit->num_ref_copies; ++i, i_qgroups += 2) {
3399                 struct btrfs_qgroup *src;
3400                 struct btrfs_qgroup *dst;
3401
3402                 if (!i_qgroups[0] || !i_qgroups[1])
3403                         continue;
3404
3405                 src = find_qgroup_rb(fs_info, i_qgroups[0]);
3406                 dst = find_qgroup_rb(fs_info, i_qgroups[1]);
3407
3408                 if (!src || !dst) {
3409                         ret = -EINVAL;
3410                         goto unlock;
3411                 }
3412
3413                 dst->rfer = src->rfer - level_size;
3414                 dst->rfer_cmpr = src->rfer_cmpr - level_size;
3415
3416                 /* Manually tweaking numbers certainly needs a rescan */
3417                 need_rescan = true;
3418         }
3419         for (i = 0; i <  inherit->num_excl_copies; ++i, i_qgroups += 2) {
3420                 struct btrfs_qgroup *src;
3421                 struct btrfs_qgroup *dst;
3422
3423                 if (!i_qgroups[0] || !i_qgroups[1])
3424                         continue;
3425
3426                 src = find_qgroup_rb(fs_info, i_qgroups[0]);
3427                 dst = find_qgroup_rb(fs_info, i_qgroups[1]);
3428
3429                 if (!src || !dst) {
3430                         ret = -EINVAL;
3431                         goto unlock;
3432                 }
3433
3434                 dst->excl = src->excl + level_size;
3435                 dst->excl_cmpr = src->excl_cmpr + level_size;
3436                 need_rescan = true;
3437         }
3438
3439 unlock:
3440         spin_unlock(&fs_info->qgroup_lock);
3441         if (!ret)
3442                 ret = btrfs_sysfs_add_one_qgroup(fs_info, dstgroup);
3443 out:
3444         if (!committing)
3445                 mutex_unlock(&fs_info->qgroup_ioctl_lock);
3446         if (need_rescan)
3447                 qgroup_mark_inconsistent(fs_info);
3448         if (qlist_prealloc) {
3449                 for (int i = 0; i < inherit->num_qgroups; i++)
3450                         kfree(qlist_prealloc[i]);
3451                 kfree(qlist_prealloc);
3452         }
3453         if (free_inherit)
3454                 kfree(inherit);
3455         kfree(prealloc);
3456         return ret;
3457 }
3458
3459 static bool qgroup_check_limits(const struct btrfs_qgroup *qg, u64 num_bytes)
3460 {
3461         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_RFER) &&
3462             qgroup_rsv_total(qg) + (s64)qg->rfer + num_bytes > qg->max_rfer)
3463                 return false;
3464
3465         if ((qg->lim_flags & BTRFS_QGROUP_LIMIT_MAX_EXCL) &&
3466             qgroup_rsv_total(qg) + (s64)qg->excl + num_bytes > qg->max_excl)
3467                 return false;
3468
3469         return true;
3470 }
3471
3472 static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes, bool enforce,
3473                           enum btrfs_qgroup_rsv_type type)
3474 {
3475         struct btrfs_qgroup *qgroup;
3476         struct btrfs_fs_info *fs_info = root->fs_info;
3477         u64 ref_root = root->root_key.objectid;
3478         int ret = 0;
3479         LIST_HEAD(qgroup_list);
3480
3481         if (!is_fstree(ref_root))
3482                 return 0;
3483
3484         if (num_bytes == 0)
3485                 return 0;
3486
3487         if (test_bit(BTRFS_FS_QUOTA_OVERRIDE, &fs_info->flags) &&
3488             capable(CAP_SYS_RESOURCE))
3489                 enforce = false;
3490
3491         spin_lock(&fs_info->qgroup_lock);
3492         if (!fs_info->quota_root)
3493                 goto out;
3494
3495         qgroup = find_qgroup_rb(fs_info, ref_root);
3496         if (!qgroup)
3497                 goto out;
3498
3499         qgroup_iterator_add(&qgroup_list, qgroup);
3500         list_for_each_entry(qgroup, &qgroup_list, iterator) {
3501                 struct btrfs_qgroup_list *glist;
3502
3503                 if (enforce && !qgroup_check_limits(qgroup, num_bytes)) {
3504                         ret = -EDQUOT;
3505                         goto out;
3506                 }
3507
3508                 list_for_each_entry(glist, &qgroup->groups, next_group)
3509                         qgroup_iterator_add(&qgroup_list, glist->group);
3510         }
3511
3512         ret = 0;
3513         /*
3514          * no limits exceeded, now record the reservation into all qgroups
3515          */
3516         list_for_each_entry(qgroup, &qgroup_list, iterator)
3517                 qgroup_rsv_add(fs_info, qgroup, num_bytes, type);
3518
3519 out:
3520         qgroup_iterator_clean(&qgroup_list);
3521         spin_unlock(&fs_info->qgroup_lock);
3522         return ret;
3523 }
3524
3525 /*
3526  * Free @num_bytes of reserved space with @type for qgroup.  (Normally level 0
3527  * qgroup).
3528  *
3529  * Will handle all higher level qgroup too.
3530  *
3531  * NOTE: If @num_bytes is (u64)-1, this means to free all bytes of this qgroup.
3532  * This special case is only used for META_PERTRANS type.
3533  */
3534 void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
3535                                u64 ref_root, u64 num_bytes,
3536                                enum btrfs_qgroup_rsv_type type)
3537 {
3538         struct btrfs_qgroup *qgroup;
3539         LIST_HEAD(qgroup_list);
3540
3541         if (!is_fstree(ref_root))
3542                 return;
3543
3544         if (num_bytes == 0)
3545                 return;
3546
3547         if (num_bytes == (u64)-1 && type != BTRFS_QGROUP_RSV_META_PERTRANS) {
3548                 WARN(1, "%s: Invalid type to free", __func__);
3549                 return;
3550         }
3551         spin_lock(&fs_info->qgroup_lock);
3552
3553         if (!fs_info->quota_root)
3554                 goto out;
3555
3556         qgroup = find_qgroup_rb(fs_info, ref_root);
3557         if (!qgroup)
3558                 goto out;
3559
3560         if (num_bytes == (u64)-1)
3561                 /*
3562                  * We're freeing all pertrans rsv, get reserved value from
3563                  * level 0 qgroup as real num_bytes to free.
3564                  */
3565                 num_bytes = qgroup->rsv.values[type];
3566
3567         qgroup_iterator_add(&qgroup_list, qgroup);
3568         list_for_each_entry(qgroup, &qgroup_list, iterator) {
3569                 struct btrfs_qgroup_list *glist;
3570
3571                 qgroup_rsv_release(fs_info, qgroup, num_bytes, type);
3572                 list_for_each_entry(glist, &qgroup->groups, next_group) {
3573                         qgroup_iterator_add(&qgroup_list, glist->group);
3574                 }
3575         }
3576 out:
3577         qgroup_iterator_clean(&qgroup_list);
3578         spin_unlock(&fs_info->qgroup_lock);
3579 }
3580
3581 /*
3582  * Check if the leaf is the last leaf. Which means all node pointers
3583  * are at their last position.
3584  */
3585 static bool is_last_leaf(struct btrfs_path *path)
3586 {
3587         int i;
3588
3589         for (i = 1; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
3590                 if (path->slots[i] != btrfs_header_nritems(path->nodes[i]) - 1)
3591                         return false;
3592         }
3593         return true;
3594 }
3595
3596 /*
3597  * returns < 0 on error, 0 when more leafs are to be scanned.
3598  * returns 1 when done.
3599  */
3600 static int qgroup_rescan_leaf(struct btrfs_trans_handle *trans,
3601                               struct btrfs_path *path)
3602 {
3603         struct btrfs_fs_info *fs_info = trans->fs_info;
3604         struct btrfs_root *extent_root;
3605         struct btrfs_key found;
3606         struct extent_buffer *scratch_leaf = NULL;
3607         u64 num_bytes;
3608         bool done;
3609         int slot;
3610         int ret;
3611
3612         if (!btrfs_qgroup_full_accounting(fs_info))
3613                 return 1;
3614
3615         mutex_lock(&fs_info->qgroup_rescan_lock);
3616         extent_root = btrfs_extent_root(fs_info,
3617                                 fs_info->qgroup_rescan_progress.objectid);
3618         ret = btrfs_search_slot_for_read(extent_root,
3619                                          &fs_info->qgroup_rescan_progress,
3620                                          path, 1, 0);
3621
3622         btrfs_debug(fs_info,
3623                 "current progress key (%llu %u %llu), search_slot ret %d",
3624                 fs_info->qgroup_rescan_progress.objectid,
3625                 fs_info->qgroup_rescan_progress.type,
3626                 fs_info->qgroup_rescan_progress.offset, ret);
3627
3628         if (ret) {
3629                 /*
3630                  * The rescan is about to end, we will not be scanning any
3631                  * further blocks. We cannot unset the RESCAN flag here, because
3632                  * we want to commit the transaction if everything went well.
3633                  * To make the live accounting work in this phase, we set our
3634                  * scan progress pointer such that every real extent objectid
3635                  * will be smaller.
3636                  */
3637                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3638                 btrfs_release_path(path);
3639                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3640                 return ret;
3641         }
3642         done = is_last_leaf(path);
3643
3644         btrfs_item_key_to_cpu(path->nodes[0], &found,
3645                               btrfs_header_nritems(path->nodes[0]) - 1);
3646         fs_info->qgroup_rescan_progress.objectid = found.objectid + 1;
3647
3648         scratch_leaf = btrfs_clone_extent_buffer(path->nodes[0]);
3649         if (!scratch_leaf) {
3650                 ret = -ENOMEM;
3651                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3652                 goto out;
3653         }
3654         slot = path->slots[0];
3655         btrfs_release_path(path);
3656         mutex_unlock(&fs_info->qgroup_rescan_lock);
3657
3658         for (; slot < btrfs_header_nritems(scratch_leaf); ++slot) {
3659                 struct btrfs_backref_walk_ctx ctx = { 0 };
3660
3661                 btrfs_item_key_to_cpu(scratch_leaf, &found, slot);
3662                 if (found.type != BTRFS_EXTENT_ITEM_KEY &&
3663                     found.type != BTRFS_METADATA_ITEM_KEY)
3664                         continue;
3665                 if (found.type == BTRFS_METADATA_ITEM_KEY)
3666                         num_bytes = fs_info->nodesize;
3667                 else
3668                         num_bytes = found.offset;
3669
3670                 ctx.bytenr = found.objectid;
3671                 ctx.fs_info = fs_info;
3672
3673                 ret = btrfs_find_all_roots(&ctx, false);
3674                 if (ret < 0)
3675                         goto out;
3676                 /* For rescan, just pass old_roots as NULL */
3677                 ret = btrfs_qgroup_account_extent(trans, found.objectid,
3678                                                   num_bytes, NULL, ctx.roots);
3679                 if (ret < 0)
3680                         goto out;
3681         }
3682 out:
3683         if (scratch_leaf)
3684                 free_extent_buffer(scratch_leaf);
3685
3686         if (done && !ret) {
3687                 ret = 1;
3688                 fs_info->qgroup_rescan_progress.objectid = (u64)-1;
3689         }
3690         return ret;
3691 }
3692
3693 static bool rescan_should_stop(struct btrfs_fs_info *fs_info)
3694 {
3695         if (btrfs_fs_closing(fs_info))
3696                 return true;
3697         if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
3698                 return true;
3699         if (!btrfs_qgroup_enabled(fs_info))
3700                 return true;
3701         if (fs_info->qgroup_flags & BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN)
3702                 return true;
3703         return false;
3704 }
3705
3706 static void btrfs_qgroup_rescan_worker(struct btrfs_work *work)
3707 {
3708         struct btrfs_fs_info *fs_info = container_of(work, struct btrfs_fs_info,
3709                                                      qgroup_rescan_work);
3710         struct btrfs_path *path;
3711         struct btrfs_trans_handle *trans = NULL;
3712         int err = -ENOMEM;
3713         int ret = 0;
3714         bool stopped = false;
3715         bool did_leaf_rescans = false;
3716
3717         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
3718                 return;
3719
3720         path = btrfs_alloc_path();
3721         if (!path)
3722                 goto out;
3723         /*
3724          * Rescan should only search for commit root, and any later difference
3725          * should be recorded by qgroup
3726          */
3727         path->search_commit_root = 1;
3728         path->skip_locking = 1;
3729
3730         err = 0;
3731         while (!err && !(stopped = rescan_should_stop(fs_info))) {
3732                 trans = btrfs_start_transaction(fs_info->fs_root, 0);
3733                 if (IS_ERR(trans)) {
3734                         err = PTR_ERR(trans);
3735                         break;
3736                 }
3737
3738                 err = qgroup_rescan_leaf(trans, path);
3739                 did_leaf_rescans = true;
3740
3741                 if (err > 0)
3742                         btrfs_commit_transaction(trans);
3743                 else
3744                         btrfs_end_transaction(trans);
3745         }
3746
3747 out:
3748         btrfs_free_path(path);
3749
3750         mutex_lock(&fs_info->qgroup_rescan_lock);
3751         if (err > 0 &&
3752             fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT) {
3753                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3754         } else if (err < 0 || stopped) {
3755                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT;
3756         }
3757         mutex_unlock(&fs_info->qgroup_rescan_lock);
3758
3759         /*
3760          * Only update status, since the previous part has already updated the
3761          * qgroup info, and only if we did any actual work. This also prevents
3762          * race with a concurrent quota disable, which has already set
3763          * fs_info->quota_root to NULL and cleared BTRFS_FS_QUOTA_ENABLED at
3764          * btrfs_quota_disable().
3765          */
3766         if (did_leaf_rescans) {
3767                 trans = btrfs_start_transaction(fs_info->quota_root, 1);
3768                 if (IS_ERR(trans)) {
3769                         err = PTR_ERR(trans);
3770                         trans = NULL;
3771                         btrfs_err(fs_info,
3772                                   "fail to start transaction for status update: %d",
3773                                   err);
3774                 }
3775         } else {
3776                 trans = NULL;
3777         }
3778
3779         mutex_lock(&fs_info->qgroup_rescan_lock);
3780         if (!stopped ||
3781             fs_info->qgroup_flags & BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN)
3782                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3783         if (trans) {
3784                 ret = update_qgroup_status_item(trans);
3785                 if (ret < 0) {
3786                         err = ret;
3787                         btrfs_err(fs_info, "fail to update qgroup status: %d",
3788                                   err);
3789                 }
3790         }
3791         fs_info->qgroup_rescan_running = false;
3792         fs_info->qgroup_flags &= ~BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN;
3793         complete_all(&fs_info->qgroup_rescan_completion);
3794         mutex_unlock(&fs_info->qgroup_rescan_lock);
3795
3796         if (!trans)
3797                 return;
3798
3799         btrfs_end_transaction(trans);
3800
3801         if (stopped) {
3802                 btrfs_info(fs_info, "qgroup scan paused");
3803         } else if (fs_info->qgroup_flags & BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN) {
3804                 btrfs_info(fs_info, "qgroup scan cancelled");
3805         } else if (err >= 0) {
3806                 btrfs_info(fs_info, "qgroup scan completed%s",
3807                         err > 0 ? " (inconsistency flag cleared)" : "");
3808         } else {
3809                 btrfs_err(fs_info, "qgroup scan failed with %d", err);
3810         }
3811 }
3812
3813 /*
3814  * Checks that (a) no rescan is running and (b) quota is enabled. Allocates all
3815  * memory required for the rescan context.
3816  */
3817 static int
3818 qgroup_rescan_init(struct btrfs_fs_info *fs_info, u64 progress_objectid,
3819                    int init_flags)
3820 {
3821         int ret = 0;
3822
3823         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE) {
3824                 btrfs_warn(fs_info, "qgroup rescan init failed, running in simple mode");
3825                 return -EINVAL;
3826         }
3827
3828         if (!init_flags) {
3829                 /* we're resuming qgroup rescan at mount time */
3830                 if (!(fs_info->qgroup_flags &
3831                       BTRFS_QGROUP_STATUS_FLAG_RESCAN)) {
3832                         btrfs_warn(fs_info,
3833                         "qgroup rescan init failed, qgroup rescan is not queued");
3834                         ret = -EINVAL;
3835                 } else if (!(fs_info->qgroup_flags &
3836                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3837                         btrfs_warn(fs_info,
3838                         "qgroup rescan init failed, qgroup is not enabled");
3839                         ret = -EINVAL;
3840                 }
3841
3842                 if (ret)
3843                         return ret;
3844         }
3845
3846         mutex_lock(&fs_info->qgroup_rescan_lock);
3847
3848         if (init_flags) {
3849                 if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
3850                         btrfs_warn(fs_info,
3851                                    "qgroup rescan is already in progress");
3852                         ret = -EINPROGRESS;
3853                 } else if (!(fs_info->qgroup_flags &
3854                              BTRFS_QGROUP_STATUS_FLAG_ON)) {
3855                         btrfs_warn(fs_info,
3856                         "qgroup rescan init failed, qgroup is not enabled");
3857                         ret = -EINVAL;
3858                 } else if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED) {
3859                         /* Quota disable is in progress */
3860                         ret = -EBUSY;
3861                 }
3862
3863                 if (ret) {
3864                         mutex_unlock(&fs_info->qgroup_rescan_lock);
3865                         return ret;
3866                 }
3867                 fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3868         }
3869
3870         memset(&fs_info->qgroup_rescan_progress, 0,
3871                 sizeof(fs_info->qgroup_rescan_progress));
3872         fs_info->qgroup_flags &= ~(BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN |
3873                                    BTRFS_QGROUP_RUNTIME_FLAG_NO_ACCOUNTING);
3874         fs_info->qgroup_rescan_progress.objectid = progress_objectid;
3875         init_completion(&fs_info->qgroup_rescan_completion);
3876         mutex_unlock(&fs_info->qgroup_rescan_lock);
3877
3878         btrfs_init_work(&fs_info->qgroup_rescan_work,
3879                         btrfs_qgroup_rescan_worker, NULL);
3880         return 0;
3881 }
3882
3883 static void
3884 qgroup_rescan_zero_tracking(struct btrfs_fs_info *fs_info)
3885 {
3886         struct rb_node *n;
3887         struct btrfs_qgroup *qgroup;
3888
3889         spin_lock(&fs_info->qgroup_lock);
3890         /* clear all current qgroup tracking information */
3891         for (n = rb_first(&fs_info->qgroup_tree); n; n = rb_next(n)) {
3892                 qgroup = rb_entry(n, struct btrfs_qgroup, node);
3893                 qgroup->rfer = 0;
3894                 qgroup->rfer_cmpr = 0;
3895                 qgroup->excl = 0;
3896                 qgroup->excl_cmpr = 0;
3897                 qgroup_dirty(fs_info, qgroup);
3898         }
3899         spin_unlock(&fs_info->qgroup_lock);
3900 }
3901
3902 int
3903 btrfs_qgroup_rescan(struct btrfs_fs_info *fs_info)
3904 {
3905         int ret = 0;
3906         struct btrfs_trans_handle *trans;
3907
3908         ret = qgroup_rescan_init(fs_info, 0, 1);
3909         if (ret)
3910                 return ret;
3911
3912         /*
3913          * We have set the rescan_progress to 0, which means no more
3914          * delayed refs will be accounted by btrfs_qgroup_account_ref.
3915          * However, btrfs_qgroup_account_ref may be right after its call
3916          * to btrfs_find_all_roots, in which case it would still do the
3917          * accounting.
3918          * To solve this, we're committing the transaction, which will
3919          * ensure we run all delayed refs and only after that, we are
3920          * going to clear all tracking information for a clean start.
3921          */
3922
3923         trans = btrfs_attach_transaction_barrier(fs_info->fs_root);
3924         if (IS_ERR(trans) && trans != ERR_PTR(-ENOENT)) {
3925                 fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3926                 return PTR_ERR(trans);
3927         } else if (trans != ERR_PTR(-ENOENT)) {
3928                 ret = btrfs_commit_transaction(trans);
3929                 if (ret) {
3930                         fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN;
3931                         return ret;
3932                 }
3933         }
3934
3935         qgroup_rescan_zero_tracking(fs_info);
3936
3937         mutex_lock(&fs_info->qgroup_rescan_lock);
3938         fs_info->qgroup_rescan_running = true;
3939         btrfs_queue_work(fs_info->qgroup_rescan_workers,
3940                          &fs_info->qgroup_rescan_work);
3941         mutex_unlock(&fs_info->qgroup_rescan_lock);
3942
3943         return 0;
3944 }
3945
3946 int btrfs_qgroup_wait_for_completion(struct btrfs_fs_info *fs_info,
3947                                      bool interruptible)
3948 {
3949         int running;
3950         int ret = 0;
3951
3952         mutex_lock(&fs_info->qgroup_rescan_lock);
3953         running = fs_info->qgroup_rescan_running;
3954         mutex_unlock(&fs_info->qgroup_rescan_lock);
3955
3956         if (!running)
3957                 return 0;
3958
3959         if (interruptible)
3960                 ret = wait_for_completion_interruptible(
3961                                         &fs_info->qgroup_rescan_completion);
3962         else
3963                 wait_for_completion(&fs_info->qgroup_rescan_completion);
3964
3965         return ret;
3966 }
3967
3968 /*
3969  * this is only called from open_ctree where we're still single threaded, thus
3970  * locking is omitted here.
3971  */
3972 void
3973 btrfs_qgroup_rescan_resume(struct btrfs_fs_info *fs_info)
3974 {
3975         if (fs_info->qgroup_flags & BTRFS_QGROUP_STATUS_FLAG_RESCAN) {
3976                 mutex_lock(&fs_info->qgroup_rescan_lock);
3977                 fs_info->qgroup_rescan_running = true;
3978                 btrfs_queue_work(fs_info->qgroup_rescan_workers,
3979                                  &fs_info->qgroup_rescan_work);
3980                 mutex_unlock(&fs_info->qgroup_rescan_lock);
3981         }
3982 }
3983
3984 #define rbtree_iterate_from_safe(node, next, start)                             \
3985        for (node = start; node && ({ next = rb_next(node); 1;}); node = next)
3986
3987 static int qgroup_unreserve_range(struct btrfs_inode *inode,
3988                                   struct extent_changeset *reserved, u64 start,
3989                                   u64 len)
3990 {
3991         struct rb_node *node;
3992         struct rb_node *next;
3993         struct ulist_node *entry;
3994         int ret = 0;
3995
3996         node = reserved->range_changed.root.rb_node;
3997         if (!node)
3998                 return 0;
3999         while (node) {
4000                 entry = rb_entry(node, struct ulist_node, rb_node);
4001                 if (entry->val < start)
4002                         node = node->rb_right;
4003                 else
4004                         node = node->rb_left;
4005         }
4006
4007         if (entry->val > start && rb_prev(&entry->rb_node))
4008                 entry = rb_entry(rb_prev(&entry->rb_node), struct ulist_node,
4009                                  rb_node);
4010
4011         rbtree_iterate_from_safe(node, next, &entry->rb_node) {
4012                 u64 entry_start;
4013                 u64 entry_end;
4014                 u64 entry_len;
4015                 int clear_ret;
4016
4017                 entry = rb_entry(node, struct ulist_node, rb_node);
4018                 entry_start = entry->val;
4019                 entry_end = entry->aux;
4020                 entry_len = entry_end - entry_start + 1;
4021
4022                 if (entry_start >= start + len)
4023                         break;
4024                 if (entry_start + entry_len <= start)
4025                         continue;
4026                 /*
4027                  * Now the entry is in [start, start + len), revert the
4028                  * EXTENT_QGROUP_RESERVED bit.
4029                  */
4030                 clear_ret = clear_extent_bits(&inode->io_tree, entry_start,
4031                                               entry_end, EXTENT_QGROUP_RESERVED);
4032                 if (!ret && clear_ret < 0)
4033                         ret = clear_ret;
4034
4035                 ulist_del(&reserved->range_changed, entry->val, entry->aux);
4036                 if (likely(reserved->bytes_changed >= entry_len)) {
4037                         reserved->bytes_changed -= entry_len;
4038                 } else {
4039                         WARN_ON(1);
4040                         reserved->bytes_changed = 0;
4041                 }
4042         }
4043
4044         return ret;
4045 }
4046
4047 /*
4048  * Try to free some space for qgroup.
4049  *
4050  * For qgroup, there are only 3 ways to free qgroup space:
4051  * - Flush nodatacow write
4052  *   Any nodatacow write will free its reserved data space at run_delalloc_range().
4053  *   In theory, we should only flush nodatacow inodes, but it's not yet
4054  *   possible, so we need to flush the whole root.
4055  *
4056  * - Wait for ordered extents
4057  *   When ordered extents are finished, their reserved metadata is finally
4058  *   converted to per_trans status, which can be freed by later commit
4059  *   transaction.
4060  *
4061  * - Commit transaction
4062  *   This would free the meta_per_trans space.
4063  *   In theory this shouldn't provide much space, but any more qgroup space
4064  *   is needed.
4065  */
4066 static int try_flush_qgroup(struct btrfs_root *root)
4067 {
4068         struct btrfs_trans_handle *trans;
4069         int ret;
4070
4071         /* Can't hold an open transaction or we run the risk of deadlocking. */
4072         ASSERT(current->journal_info == NULL);
4073         if (WARN_ON(current->journal_info))
4074                 return 0;
4075
4076         /*
4077          * We don't want to run flush again and again, so if there is a running
4078          * one, we won't try to start a new flush, but exit directly.
4079          */
4080         if (test_and_set_bit(BTRFS_ROOT_QGROUP_FLUSHING, &root->state)) {
4081                 wait_event(root->qgroup_flush_wait,
4082                         !test_bit(BTRFS_ROOT_QGROUP_FLUSHING, &root->state));
4083                 return 0;
4084         }
4085
4086         ret = btrfs_start_delalloc_snapshot(root, true);
4087         if (ret < 0)
4088                 goto out;
4089         btrfs_wait_ordered_extents(root, U64_MAX, 0, (u64)-1);
4090
4091         trans = btrfs_attach_transaction_barrier(root);
4092         if (IS_ERR(trans)) {
4093                 ret = PTR_ERR(trans);
4094                 if (ret == -ENOENT)
4095                         ret = 0;
4096                 goto out;
4097         }
4098
4099         ret = btrfs_commit_transaction(trans);
4100 out:
4101         clear_bit(BTRFS_ROOT_QGROUP_FLUSHING, &root->state);
4102         wake_up(&root->qgroup_flush_wait);
4103         return ret;
4104 }
4105
4106 static int qgroup_reserve_data(struct btrfs_inode *inode,
4107                         struct extent_changeset **reserved_ret, u64 start,
4108                         u64 len)
4109 {
4110         struct btrfs_root *root = inode->root;
4111         struct extent_changeset *reserved;
4112         bool new_reserved = false;
4113         u64 orig_reserved;
4114         u64 to_reserve;
4115         int ret;
4116
4117         if (btrfs_qgroup_mode(root->fs_info) == BTRFS_QGROUP_MODE_DISABLED ||
4118             !is_fstree(root->root_key.objectid) || len == 0)
4119                 return 0;
4120
4121         /* @reserved parameter is mandatory for qgroup */
4122         if (WARN_ON(!reserved_ret))
4123                 return -EINVAL;
4124         if (!*reserved_ret) {
4125                 new_reserved = true;
4126                 *reserved_ret = extent_changeset_alloc();
4127                 if (!*reserved_ret)
4128                         return -ENOMEM;
4129         }
4130         reserved = *reserved_ret;
4131         /* Record already reserved space */
4132         orig_reserved = reserved->bytes_changed;
4133         ret = set_record_extent_bits(&inode->io_tree, start,
4134                         start + len -1, EXTENT_QGROUP_RESERVED, reserved);
4135
4136         /* Newly reserved space */
4137         to_reserve = reserved->bytes_changed - orig_reserved;
4138         trace_btrfs_qgroup_reserve_data(&inode->vfs_inode, start, len,
4139                                         to_reserve, QGROUP_RESERVE);
4140         if (ret < 0)
4141                 goto out;
4142         ret = qgroup_reserve(root, to_reserve, true, BTRFS_QGROUP_RSV_DATA);
4143         if (ret < 0)
4144                 goto cleanup;
4145
4146         return ret;
4147
4148 cleanup:
4149         qgroup_unreserve_range(inode, reserved, start, len);
4150 out:
4151         if (new_reserved) {
4152                 extent_changeset_free(reserved);
4153                 *reserved_ret = NULL;
4154         }
4155         return ret;
4156 }
4157
4158 /*
4159  * Reserve qgroup space for range [start, start + len).
4160  *
4161  * This function will either reserve space from related qgroups or do nothing
4162  * if the range is already reserved.
4163  *
4164  * Return 0 for successful reservation
4165  * Return <0 for error (including -EQUOT)
4166  *
4167  * NOTE: This function may sleep for memory allocation, dirty page flushing and
4168  *       commit transaction. So caller should not hold any dirty page locked.
4169  */
4170 int btrfs_qgroup_reserve_data(struct btrfs_inode *inode,
4171                         struct extent_changeset **reserved_ret, u64 start,
4172                         u64 len)
4173 {
4174         int ret;
4175
4176         ret = qgroup_reserve_data(inode, reserved_ret, start, len);
4177         if (ret <= 0 && ret != -EDQUOT)
4178                 return ret;
4179
4180         ret = try_flush_qgroup(inode->root);
4181         if (ret < 0)
4182                 return ret;
4183         return qgroup_reserve_data(inode, reserved_ret, start, len);
4184 }
4185
4186 /* Free ranges specified by @reserved, normally in error path */
4187 static int qgroup_free_reserved_data(struct btrfs_inode *inode,
4188                                      struct extent_changeset *reserved,
4189                                      u64 start, u64 len, u64 *freed_ret)
4190 {
4191         struct btrfs_root *root = inode->root;
4192         struct ulist_node *unode;
4193         struct ulist_iterator uiter;
4194         struct extent_changeset changeset;
4195         u64 freed = 0;
4196         int ret;
4197
4198         extent_changeset_init(&changeset);
4199         len = round_up(start + len, root->fs_info->sectorsize);
4200         start = round_down(start, root->fs_info->sectorsize);
4201
4202         ULIST_ITER_INIT(&uiter);
4203         while ((unode = ulist_next(&reserved->range_changed, &uiter))) {
4204                 u64 range_start = unode->val;
4205                 /* unode->aux is the inclusive end */
4206                 u64 range_len = unode->aux - range_start + 1;
4207                 u64 free_start;
4208                 u64 free_len;
4209
4210                 extent_changeset_release(&changeset);
4211
4212                 /* Only free range in range [start, start + len) */
4213                 if (range_start >= start + len ||
4214                     range_start + range_len <= start)
4215                         continue;
4216                 free_start = max(range_start, start);
4217                 free_len = min(start + len, range_start + range_len) -
4218                            free_start;
4219                 /*
4220                  * TODO: To also modify reserved->ranges_reserved to reflect
4221                  * the modification.
4222                  *
4223                  * However as long as we free qgroup reserved according to
4224                  * EXTENT_QGROUP_RESERVED, we won't double free.
4225                  * So not need to rush.
4226                  */
4227                 ret = clear_record_extent_bits(&inode->io_tree, free_start,
4228                                 free_start + free_len - 1,
4229                                 EXTENT_QGROUP_RESERVED, &changeset);
4230                 if (ret < 0)
4231                         goto out;
4232                 freed += changeset.bytes_changed;
4233         }
4234         btrfs_qgroup_free_refroot(root->fs_info, root->root_key.objectid, freed,
4235                                   BTRFS_QGROUP_RSV_DATA);
4236         if (freed_ret)
4237                 *freed_ret = freed;
4238         ret = 0;
4239 out:
4240         extent_changeset_release(&changeset);
4241         return ret;
4242 }
4243
4244 static int __btrfs_qgroup_release_data(struct btrfs_inode *inode,
4245                         struct extent_changeset *reserved, u64 start, u64 len,
4246                         u64 *released, int free)
4247 {
4248         struct extent_changeset changeset;
4249         int trace_op = QGROUP_RELEASE;
4250         int ret;
4251
4252         if (btrfs_qgroup_mode(inode->root->fs_info) == BTRFS_QGROUP_MODE_DISABLED) {
4253                 extent_changeset_init(&changeset);
4254                 return clear_record_extent_bits(&inode->io_tree, start,
4255                                                 start + len - 1,
4256                                                 EXTENT_QGROUP_RESERVED, &changeset);
4257         }
4258
4259         /* In release case, we shouldn't have @reserved */
4260         WARN_ON(!free && reserved);
4261         if (free && reserved)
4262                 return qgroup_free_reserved_data(inode, reserved, start, len, released);
4263         extent_changeset_init(&changeset);
4264         ret = clear_record_extent_bits(&inode->io_tree, start, start + len -1,
4265                                        EXTENT_QGROUP_RESERVED, &changeset);
4266         if (ret < 0)
4267                 goto out;
4268
4269         if (free)
4270                 trace_op = QGROUP_FREE;
4271         trace_btrfs_qgroup_release_data(&inode->vfs_inode, start, len,
4272                                         changeset.bytes_changed, trace_op);
4273         if (free)
4274                 btrfs_qgroup_free_refroot(inode->root->fs_info,
4275                                 inode->root->root_key.objectid,
4276                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
4277         if (released)
4278                 *released = changeset.bytes_changed;
4279 out:
4280         extent_changeset_release(&changeset);
4281         return ret;
4282 }
4283
4284 /*
4285  * Free a reserved space range from io_tree and related qgroups
4286  *
4287  * Should be called when a range of pages get invalidated before reaching disk.
4288  * Or for error cleanup case.
4289  * if @reserved is given, only reserved range in [@start, @start + @len) will
4290  * be freed.
4291  *
4292  * For data written to disk, use btrfs_qgroup_release_data().
4293  *
4294  * NOTE: This function may sleep for memory allocation.
4295  */
4296 int btrfs_qgroup_free_data(struct btrfs_inode *inode,
4297                            struct extent_changeset *reserved,
4298                            u64 start, u64 len, u64 *freed)
4299 {
4300         return __btrfs_qgroup_release_data(inode, reserved, start, len, freed, 1);
4301 }
4302
4303 /*
4304  * Release a reserved space range from io_tree only.
4305  *
4306  * Should be called when a range of pages get written to disk and corresponding
4307  * FILE_EXTENT is inserted into corresponding root.
4308  *
4309  * Since new qgroup accounting framework will only update qgroup numbers at
4310  * commit_transaction() time, its reserved space shouldn't be freed from
4311  * related qgroups.
4312  *
4313  * But we should release the range from io_tree, to allow further write to be
4314  * COWed.
4315  *
4316  * NOTE: This function may sleep for memory allocation.
4317  */
4318 int btrfs_qgroup_release_data(struct btrfs_inode *inode, u64 start, u64 len, u64 *released)
4319 {
4320         return __btrfs_qgroup_release_data(inode, NULL, start, len, released, 0);
4321 }
4322
4323 static void add_root_meta_rsv(struct btrfs_root *root, int num_bytes,
4324                               enum btrfs_qgroup_rsv_type type)
4325 {
4326         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
4327             type != BTRFS_QGROUP_RSV_META_PERTRANS)
4328                 return;
4329         if (num_bytes == 0)
4330                 return;
4331
4332         spin_lock(&root->qgroup_meta_rsv_lock);
4333         if (type == BTRFS_QGROUP_RSV_META_PREALLOC)
4334                 root->qgroup_meta_rsv_prealloc += num_bytes;
4335         else
4336                 root->qgroup_meta_rsv_pertrans += num_bytes;
4337         spin_unlock(&root->qgroup_meta_rsv_lock);
4338 }
4339
4340 static int sub_root_meta_rsv(struct btrfs_root *root, int num_bytes,
4341                              enum btrfs_qgroup_rsv_type type)
4342 {
4343         if (type != BTRFS_QGROUP_RSV_META_PREALLOC &&
4344             type != BTRFS_QGROUP_RSV_META_PERTRANS)
4345                 return 0;
4346         if (num_bytes == 0)
4347                 return 0;
4348
4349         spin_lock(&root->qgroup_meta_rsv_lock);
4350         if (type == BTRFS_QGROUP_RSV_META_PREALLOC) {
4351                 num_bytes = min_t(u64, root->qgroup_meta_rsv_prealloc,
4352                                   num_bytes);
4353                 root->qgroup_meta_rsv_prealloc -= num_bytes;
4354         } else {
4355                 num_bytes = min_t(u64, root->qgroup_meta_rsv_pertrans,
4356                                   num_bytes);
4357                 root->qgroup_meta_rsv_pertrans -= num_bytes;
4358         }
4359         spin_unlock(&root->qgroup_meta_rsv_lock);
4360         return num_bytes;
4361 }
4362
4363 int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
4364                               enum btrfs_qgroup_rsv_type type, bool enforce)
4365 {
4366         struct btrfs_fs_info *fs_info = root->fs_info;
4367         int ret;
4368
4369         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED ||
4370             !is_fstree(root->root_key.objectid) || num_bytes == 0)
4371                 return 0;
4372
4373         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
4374         trace_qgroup_meta_reserve(root, (s64)num_bytes, type);
4375         ret = qgroup_reserve(root, num_bytes, enforce, type);
4376         if (ret < 0)
4377                 return ret;
4378         /*
4379          * Record what we have reserved into root.
4380          *
4381          * To avoid quota disabled->enabled underflow.
4382          * In that case, we may try to free space we haven't reserved
4383          * (since quota was disabled), so record what we reserved into root.
4384          * And ensure later release won't underflow this number.
4385          */
4386         add_root_meta_rsv(root, num_bytes, type);
4387         return ret;
4388 }
4389
4390 int __btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes,
4391                                 enum btrfs_qgroup_rsv_type type, bool enforce,
4392                                 bool noflush)
4393 {
4394         int ret;
4395
4396         ret = btrfs_qgroup_reserve_meta(root, num_bytes, type, enforce);
4397         if ((ret <= 0 && ret != -EDQUOT) || noflush)
4398                 return ret;
4399
4400         ret = try_flush_qgroup(root);
4401         if (ret < 0)
4402                 return ret;
4403         return btrfs_qgroup_reserve_meta(root, num_bytes, type, enforce);
4404 }
4405
4406 /*
4407  * Per-transaction meta reservation should be all freed at transaction commit
4408  * time
4409  */
4410 void btrfs_qgroup_free_meta_all_pertrans(struct btrfs_root *root)
4411 {
4412         struct btrfs_fs_info *fs_info = root->fs_info;
4413
4414         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED ||
4415             !is_fstree(root->root_key.objectid))
4416                 return;
4417
4418         /* TODO: Update trace point to handle such free */
4419         trace_qgroup_meta_free_all_pertrans(root);
4420         /* Special value -1 means to free all reserved space */
4421         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid, (u64)-1,
4422                                   BTRFS_QGROUP_RSV_META_PERTRANS);
4423 }
4424
4425 void __btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes,
4426                               enum btrfs_qgroup_rsv_type type)
4427 {
4428         struct btrfs_fs_info *fs_info = root->fs_info;
4429
4430         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED ||
4431             !is_fstree(root->root_key.objectid))
4432                 return;
4433
4434         /*
4435          * reservation for META_PREALLOC can happen before quota is enabled,
4436          * which can lead to underflow.
4437          * Here ensure we will only free what we really have reserved.
4438          */
4439         num_bytes = sub_root_meta_rsv(root, num_bytes, type);
4440         BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
4441         trace_qgroup_meta_reserve(root, -(s64)num_bytes, type);
4442         btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
4443                                   num_bytes, type);
4444 }
4445
4446 static void qgroup_convert_meta(struct btrfs_fs_info *fs_info, u64 ref_root,
4447                                 int num_bytes)
4448 {
4449         struct btrfs_qgroup *qgroup;
4450         LIST_HEAD(qgroup_list);
4451
4452         if (num_bytes == 0)
4453                 return;
4454         if (!fs_info->quota_root)
4455                 return;
4456
4457         spin_lock(&fs_info->qgroup_lock);
4458         qgroup = find_qgroup_rb(fs_info, ref_root);
4459         if (!qgroup)
4460                 goto out;
4461
4462         qgroup_iterator_add(&qgroup_list, qgroup);
4463         list_for_each_entry(qgroup, &qgroup_list, iterator) {
4464                 struct btrfs_qgroup_list *glist;
4465
4466                 qgroup_rsv_release(fs_info, qgroup, num_bytes,
4467                                 BTRFS_QGROUP_RSV_META_PREALLOC);
4468                 if (!sb_rdonly(fs_info->sb))
4469                         qgroup_rsv_add(fs_info, qgroup, num_bytes,
4470                                        BTRFS_QGROUP_RSV_META_PERTRANS);
4471
4472                 list_for_each_entry(glist, &qgroup->groups, next_group)
4473                         qgroup_iterator_add(&qgroup_list, glist->group);
4474         }
4475 out:
4476         qgroup_iterator_clean(&qgroup_list);
4477         spin_unlock(&fs_info->qgroup_lock);
4478 }
4479
4480 /*
4481  * Convert @num_bytes of META_PREALLOCATED reservation to META_PERTRANS.
4482  *
4483  * This is called when preallocated meta reservation needs to be used.
4484  * Normally after btrfs_join_transaction() call.
4485  */
4486 void btrfs_qgroup_convert_reserved_meta(struct btrfs_root *root, int num_bytes)
4487 {
4488         struct btrfs_fs_info *fs_info = root->fs_info;
4489
4490         if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_DISABLED ||
4491             !is_fstree(root->root_key.objectid))
4492                 return;
4493         /* Same as btrfs_qgroup_free_meta_prealloc() */
4494         num_bytes = sub_root_meta_rsv(root, num_bytes,
4495                                       BTRFS_QGROUP_RSV_META_PREALLOC);
4496         trace_qgroup_meta_convert(root, num_bytes);
4497         qgroup_convert_meta(fs_info, root->root_key.objectid, num_bytes);
4498 }
4499
4500 /*
4501  * Check qgroup reserved space leaking, normally at destroy inode
4502  * time
4503  */
4504 void btrfs_qgroup_check_reserved_leak(struct btrfs_inode *inode)
4505 {
4506         struct extent_changeset changeset;
4507         struct ulist_node *unode;
4508         struct ulist_iterator iter;
4509         int ret;
4510
4511         extent_changeset_init(&changeset);
4512         ret = clear_record_extent_bits(&inode->io_tree, 0, (u64)-1,
4513                         EXTENT_QGROUP_RESERVED, &changeset);
4514
4515         WARN_ON(ret < 0);
4516         if (WARN_ON(changeset.bytes_changed)) {
4517                 ULIST_ITER_INIT(&iter);
4518                 while ((unode = ulist_next(&changeset.range_changed, &iter))) {
4519                         btrfs_warn(inode->root->fs_info,
4520                 "leaking qgroup reserved space, ino: %llu, start: %llu, end: %llu",
4521                                 btrfs_ino(inode), unode->val, unode->aux);
4522                 }
4523                 btrfs_qgroup_free_refroot(inode->root->fs_info,
4524                                 inode->root->root_key.objectid,
4525                                 changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
4526
4527         }
4528         extent_changeset_release(&changeset);
4529 }
4530
4531 void btrfs_qgroup_init_swapped_blocks(
4532         struct btrfs_qgroup_swapped_blocks *swapped_blocks)
4533 {
4534         int i;
4535
4536         spin_lock_init(&swapped_blocks->lock);
4537         for (i = 0; i < BTRFS_MAX_LEVEL; i++)
4538                 swapped_blocks->blocks[i] = RB_ROOT;
4539         swapped_blocks->swapped = false;
4540 }
4541
4542 /*
4543  * Delete all swapped blocks record of @root.
4544  * Every record here means we skipped a full subtree scan for qgroup.
4545  *
4546  * Gets called when committing one transaction.
4547  */
4548 void btrfs_qgroup_clean_swapped_blocks(struct btrfs_root *root)
4549 {
4550         struct btrfs_qgroup_swapped_blocks *swapped_blocks;
4551         int i;
4552
4553         swapped_blocks = &root->swapped_blocks;
4554
4555         spin_lock(&swapped_blocks->lock);
4556         if (!swapped_blocks->swapped)
4557                 goto out;
4558         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
4559                 struct rb_root *cur_root = &swapped_blocks->blocks[i];
4560                 struct btrfs_qgroup_swapped_block *entry;
4561                 struct btrfs_qgroup_swapped_block *next;
4562
4563                 rbtree_postorder_for_each_entry_safe(entry, next, cur_root,
4564                                                      node)
4565                         kfree(entry);
4566                 swapped_blocks->blocks[i] = RB_ROOT;
4567         }
4568         swapped_blocks->swapped = false;
4569 out:
4570         spin_unlock(&swapped_blocks->lock);
4571 }
4572
4573 /*
4574  * Add subtree roots record into @subvol_root.
4575  *
4576  * @subvol_root:        tree root of the subvolume tree get swapped
4577  * @bg:                 block group under balance
4578  * @subvol_parent/slot: pointer to the subtree root in subvolume tree
4579  * @reloc_parent/slot:  pointer to the subtree root in reloc tree
4580  *                      BOTH POINTERS ARE BEFORE TREE SWAP
4581  * @last_snapshot:      last snapshot generation of the subvolume tree
4582  */
4583 int btrfs_qgroup_add_swapped_blocks(struct btrfs_trans_handle *trans,
4584                 struct btrfs_root *subvol_root,
4585                 struct btrfs_block_group *bg,
4586                 struct extent_buffer *subvol_parent, int subvol_slot,
4587                 struct extent_buffer *reloc_parent, int reloc_slot,
4588                 u64 last_snapshot)
4589 {
4590         struct btrfs_fs_info *fs_info = subvol_root->fs_info;
4591         struct btrfs_qgroup_swapped_blocks *blocks = &subvol_root->swapped_blocks;
4592         struct btrfs_qgroup_swapped_block *block;
4593         struct rb_node **cur;
4594         struct rb_node *parent = NULL;
4595         int level = btrfs_header_level(subvol_parent) - 1;
4596         int ret = 0;
4597
4598         if (!btrfs_qgroup_full_accounting(fs_info))
4599                 return 0;
4600
4601         if (btrfs_node_ptr_generation(subvol_parent, subvol_slot) >
4602             btrfs_node_ptr_generation(reloc_parent, reloc_slot)) {
4603                 btrfs_err_rl(fs_info,
4604                 "%s: bad parameter order, subvol_gen=%llu reloc_gen=%llu",
4605                         __func__,
4606                         btrfs_node_ptr_generation(subvol_parent, subvol_slot),
4607                         btrfs_node_ptr_generation(reloc_parent, reloc_slot));
4608                 return -EUCLEAN;
4609         }
4610
4611         block = kmalloc(sizeof(*block), GFP_NOFS);
4612         if (!block) {
4613                 ret = -ENOMEM;
4614                 goto out;
4615         }
4616
4617         /*
4618          * @reloc_parent/slot is still before swap, while @block is going to
4619          * record the bytenr after swap, so we do the swap here.
4620          */
4621         block->subvol_bytenr = btrfs_node_blockptr(reloc_parent, reloc_slot);
4622         block->subvol_generation = btrfs_node_ptr_generation(reloc_parent,
4623                                                              reloc_slot);
4624         block->reloc_bytenr = btrfs_node_blockptr(subvol_parent, subvol_slot);
4625         block->reloc_generation = btrfs_node_ptr_generation(subvol_parent,
4626                                                             subvol_slot);
4627         block->last_snapshot = last_snapshot;
4628         block->level = level;
4629
4630         /*
4631          * If we have bg == NULL, we're called from btrfs_recover_relocation(),
4632          * no one else can modify tree blocks thus we qgroup will not change
4633          * no matter the value of trace_leaf.
4634          */
4635         if (bg && bg->flags & BTRFS_BLOCK_GROUP_DATA)
4636                 block->trace_leaf = true;
4637         else
4638                 block->trace_leaf = false;
4639         btrfs_node_key_to_cpu(reloc_parent, &block->first_key, reloc_slot);
4640
4641         /* Insert @block into @blocks */
4642         spin_lock(&blocks->lock);
4643         cur = &blocks->blocks[level].rb_node;
4644         while (*cur) {
4645                 struct btrfs_qgroup_swapped_block *entry;
4646
4647                 parent = *cur;
4648                 entry = rb_entry(parent, struct btrfs_qgroup_swapped_block,
4649                                  node);
4650
4651                 if (entry->subvol_bytenr < block->subvol_bytenr) {
4652                         cur = &(*cur)->rb_left;
4653                 } else if (entry->subvol_bytenr > block->subvol_bytenr) {
4654                         cur = &(*cur)->rb_right;
4655                 } else {
4656                         if (entry->subvol_generation !=
4657                                         block->subvol_generation ||
4658                             entry->reloc_bytenr != block->reloc_bytenr ||
4659                             entry->reloc_generation !=
4660                                         block->reloc_generation) {
4661                                 /*
4662                                  * Duplicated but mismatch entry found.
4663                                  * Shouldn't happen.
4664                                  *
4665                                  * Marking qgroup inconsistent should be enough
4666                                  * for end users.
4667                                  */
4668                                 WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
4669                                 ret = -EEXIST;
4670                         }
4671                         kfree(block);
4672                         goto out_unlock;
4673                 }
4674         }
4675         rb_link_node(&block->node, parent, cur);
4676         rb_insert_color(&block->node, &blocks->blocks[level]);
4677         blocks->swapped = true;
4678 out_unlock:
4679         spin_unlock(&blocks->lock);
4680 out:
4681         if (ret < 0)
4682                 qgroup_mark_inconsistent(fs_info);
4683         return ret;
4684 }
4685
4686 /*
4687  * Check if the tree block is a subtree root, and if so do the needed
4688  * delayed subtree trace for qgroup.
4689  *
4690  * This is called during btrfs_cow_block().
4691  */
4692 int btrfs_qgroup_trace_subtree_after_cow(struct btrfs_trans_handle *trans,
4693                                          struct btrfs_root *root,
4694                                          struct extent_buffer *subvol_eb)
4695 {
4696         struct btrfs_fs_info *fs_info = root->fs_info;
4697         struct btrfs_tree_parent_check check = { 0 };
4698         struct btrfs_qgroup_swapped_blocks *blocks = &root->swapped_blocks;
4699         struct btrfs_qgroup_swapped_block *block;
4700         struct extent_buffer *reloc_eb = NULL;
4701         struct rb_node *node;
4702         bool found = false;
4703         bool swapped = false;
4704         int level = btrfs_header_level(subvol_eb);
4705         int ret = 0;
4706         int i;
4707
4708         if (!btrfs_qgroup_full_accounting(fs_info))
4709                 return 0;
4710         if (!is_fstree(root->root_key.objectid) || !root->reloc_root)
4711                 return 0;
4712
4713         spin_lock(&blocks->lock);
4714         if (!blocks->swapped) {
4715                 spin_unlock(&blocks->lock);
4716                 return 0;
4717         }
4718         node = blocks->blocks[level].rb_node;
4719
4720         while (node) {
4721                 block = rb_entry(node, struct btrfs_qgroup_swapped_block, node);
4722                 if (block->subvol_bytenr < subvol_eb->start) {
4723                         node = node->rb_left;
4724                 } else if (block->subvol_bytenr > subvol_eb->start) {
4725                         node = node->rb_right;
4726                 } else {
4727                         found = true;
4728                         break;
4729                 }
4730         }
4731         if (!found) {
4732                 spin_unlock(&blocks->lock);
4733                 goto out;
4734         }
4735         /* Found one, remove it from @blocks first and update blocks->swapped */
4736         rb_erase(&block->node, &blocks->blocks[level]);
4737         for (i = 0; i < BTRFS_MAX_LEVEL; i++) {
4738                 if (RB_EMPTY_ROOT(&blocks->blocks[i])) {
4739                         swapped = true;
4740                         break;
4741                 }
4742         }
4743         blocks->swapped = swapped;
4744         spin_unlock(&blocks->lock);
4745
4746         check.level = block->level;
4747         check.transid = block->reloc_generation;
4748         check.has_first_key = true;
4749         memcpy(&check.first_key, &block->first_key, sizeof(check.first_key));
4750
4751         /* Read out reloc subtree root */
4752         reloc_eb = read_tree_block(fs_info, block->reloc_bytenr, &check);
4753         if (IS_ERR(reloc_eb)) {
4754                 ret = PTR_ERR(reloc_eb);
4755                 reloc_eb = NULL;
4756                 goto free_out;
4757         }
4758         if (!extent_buffer_uptodate(reloc_eb)) {
4759                 ret = -EIO;
4760                 goto free_out;
4761         }
4762
4763         ret = qgroup_trace_subtree_swap(trans, reloc_eb, subvol_eb,
4764                         block->last_snapshot, block->trace_leaf);
4765 free_out:
4766         kfree(block);
4767         free_extent_buffer(reloc_eb);
4768 out:
4769         if (ret < 0) {
4770                 btrfs_err_rl(fs_info,
4771                              "failed to account subtree at bytenr %llu: %d",
4772                              subvol_eb->start, ret);
4773                 qgroup_mark_inconsistent(fs_info);
4774         }
4775         return ret;
4776 }
4777
4778 void btrfs_qgroup_destroy_extent_records(struct btrfs_transaction *trans)
4779 {
4780         struct btrfs_qgroup_extent_record *entry;
4781         struct btrfs_qgroup_extent_record *next;
4782         struct rb_root *root;
4783
4784         root = &trans->delayed_refs.dirty_extent_root;
4785         rbtree_postorder_for_each_entry_safe(entry, next, root, node) {
4786                 ulist_free(entry->old_roots);
4787                 kfree(entry);
4788         }
4789         *root = RB_ROOT;
4790 }
4791
4792 void btrfs_free_squota_rsv(struct btrfs_fs_info *fs_info, u64 root, u64 rsv_bytes)
4793 {
4794         if (btrfs_qgroup_mode(fs_info) != BTRFS_QGROUP_MODE_SIMPLE)
4795                 return;
4796
4797         if (!is_fstree(root))
4798                 return;
4799
4800         btrfs_qgroup_free_refroot(fs_info, root, rsv_bytes, BTRFS_QGROUP_RSV_DATA);
4801 }
4802
4803 int btrfs_record_squota_delta(struct btrfs_fs_info *fs_info,
4804                               struct btrfs_squota_delta *delta)
4805 {
4806         int ret;
4807         struct btrfs_qgroup *qgroup;
4808         struct btrfs_qgroup *qg;
4809         LIST_HEAD(qgroup_list);
4810         u64 root = delta->root;
4811         u64 num_bytes = delta->num_bytes;
4812         const int sign = (delta->is_inc ? 1 : -1);
4813
4814         if (btrfs_qgroup_mode(fs_info) != BTRFS_QGROUP_MODE_SIMPLE)
4815                 return 0;
4816
4817         if (!is_fstree(root))
4818                 return 0;
4819
4820         /* If the extent predates enabling quotas, don't count it. */
4821         if (delta->generation < fs_info->qgroup_enable_gen)
4822                 return 0;
4823
4824         spin_lock(&fs_info->qgroup_lock);
4825         qgroup = find_qgroup_rb(fs_info, root);
4826         if (!qgroup) {
4827                 ret = -ENOENT;
4828                 goto out;
4829         }
4830
4831         ret = 0;
4832         qgroup_iterator_add(&qgroup_list, qgroup);
4833         list_for_each_entry(qg, &qgroup_list, iterator) {
4834                 struct btrfs_qgroup_list *glist;
4835
4836                 qg->excl += num_bytes * sign;
4837                 qg->rfer += num_bytes * sign;
4838                 qgroup_dirty(fs_info, qg);
4839
4840                 list_for_each_entry(glist, &qg->groups, next_group)
4841                         qgroup_iterator_add(&qgroup_list, glist->group);
4842         }
4843         qgroup_iterator_clean(&qgroup_list);
4844
4845 out:
4846         spin_unlock(&fs_info->qgroup_lock);
4847         return ret;
4848 }