fs/btrfs/inode-item.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include "ctree.h"
   7 #include "fs.h"
   8 #include "messages.h"
   9 #include "inode-item.h"
  10 #include "disk-io.h"
  11 #include "transaction.h"
  12 #include "space-info.h"
  13 #include "accessors.h"
  14 #include "extent-tree.h"
  15 #include "file-item.h"
  16
  17 struct btrfs_inode_ref *btrfs_find_name_in_backref(struct extent_buffer *leaf,
  18                                                    int slot,
  19                                                    const struct fscrypt_str *name)
  20 {
  21         struct btrfs_inode_ref *ref;
  22         unsigned long ptr;
  23         unsigned long name_ptr;
  24         u32 item_size;
  25         u32 cur_offset = 0;
  26         int len;
  27
  28         item_size = btrfs_item_size(leaf, slot);
  29         ptr = btrfs_item_ptr_offset(leaf, slot);
  30         while (cur_offset < item_size) {
  31                 ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
  32                 len = btrfs_inode_ref_name_len(leaf, ref);
  33                 name_ptr = (unsigned long)(ref + 1);
  34                 cur_offset += len + sizeof(*ref);
  35                 if (len != name->len)
  36                         continue;
  37                 if (memcmp_extent_buffer(leaf, name->name, name_ptr,
  38                                          name->len) == 0)
  39                         return ref;
  40         }
  41         return NULL;
  42 }
  43
  44 struct btrfs_inode_extref *btrfs_find_name_in_ext_backref(
  45                 struct extent_buffer *leaf, int slot, u64 ref_objectid,
  46                 const struct fscrypt_str *name)
  47 {
  48         struct btrfs_inode_extref *extref;
  49         unsigned long ptr;
  50         unsigned long name_ptr;
  51         u32 item_size;
  52         u32 cur_offset = 0;
  53         int ref_name_len;
  54
  55         item_size = btrfs_item_size(leaf, slot);
  56         ptr = btrfs_item_ptr_offset(leaf, slot);
  57
  58         /*
  59          * Search all extended backrefs in this item. We're only
  60          * looking through any collisions so most of the time this is
  61          * just going to compare against one buffer. If all is well,
  62          * we'll return success and the inode ref object.
  63          */
  64         while (cur_offset < item_size) {
  65                 extref = (struct btrfs_inode_extref *) (ptr + cur_offset);
  66                 name_ptr = (unsigned long)(&extref->name);
  67                 ref_name_len = btrfs_inode_extref_name_len(leaf, extref);
  68
  69                 if (ref_name_len == name->len &&
  70                     btrfs_inode_extref_parent(leaf, extref) == ref_objectid &&
  71                     (memcmp_extent_buffer(leaf, name->name, name_ptr,
  72                                           name->len) == 0))
  73                         return extref;
  74
  75                 cur_offset += ref_name_len + sizeof(*extref);
  76         }
  77         return NULL;
  78 }
  79
  80 /* Returns NULL if no extref found */
  81 struct btrfs_inode_extref *
  82 btrfs_lookup_inode_extref(struct btrfs_trans_handle *trans,
  83                           struct btrfs_root *root,
  84                           struct btrfs_path *path,
  85                           const struct fscrypt_str *name,
  86                           u64 inode_objectid, u64 ref_objectid, int ins_len,
  87                           int cow)
  88 {
  89         int ret;
  90         struct btrfs_key key;
  91
  92         key.objectid = inode_objectid;
  93         key.type = BTRFS_INODE_EXTREF_KEY;
  94         key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
  95
  96         ret = btrfs_search_slot(trans, root, &key, path, ins_len, cow);
  97         if (ret < 0)
  98                 return ERR_PTR(ret);
  99         if (ret > 0)
 100                 return NULL;
 101         return btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
 102                                               ref_objectid, name);
 103
 104 }
 105
 106 static int btrfs_del_inode_extref(struct btrfs_trans_handle *trans,
 107                                   struct btrfs_root *root,
 108                                   const struct fscrypt_str *name,
 109                                   u64 inode_objectid, u64 ref_objectid,
 110                                   u64 *index)
 111 {
 112         struct btrfs_path *path;
 113         struct btrfs_key key;
 114         struct btrfs_inode_extref *extref;
 115         struct extent_buffer *leaf;
 116         int ret;
 117         int del_len = name->len + sizeof(*extref);
 118         unsigned long ptr;
 119         unsigned long item_start;
 120         u32 item_size;
 121
 122         key.objectid = inode_objectid;
 123         key.type = BTRFS_INODE_EXTREF_KEY;
 124         key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
 125
 126         path = btrfs_alloc_path();
 127         if (!path)
 128                 return -ENOMEM;
 129
 130         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 131         if (ret > 0)
 132                 ret = -ENOENT;
 133         if (ret < 0)
 134                 goto out;
 135
 136         /*
 137          * Sanity check - did we find the right item for this name?
 138          * This should always succeed so error here will make the FS
 139          * readonly.
 140          */
 141         extref = btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
 142                                                 ref_objectid, name);
 143         if (!extref) {
 144                 btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL);
 145                 ret = -EROFS;
 146                 goto out;
 147         }
 148
 149         leaf = path->nodes[0];
 150         item_size = btrfs_item_size(leaf, path->slots[0]);
 151         if (index)
 152                 *index = btrfs_inode_extref_index(leaf, extref);
 153
 154         if (del_len == item_size) {
 155                 /*
 156                  * Common case only one ref in the item, remove the
 157                  * whole item.
 158                  */
 159                 ret = btrfs_del_item(trans, root, path);
 160                 goto out;
 161         }
 162
 163         ptr = (unsigned long)extref;
 164         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 165
 166         memmove_extent_buffer(leaf, ptr, ptr + del_len,
 167                               item_size - (ptr + del_len - item_start));
 168
 169         btrfs_truncate_item(trans, path, item_size - del_len, 1);
 170
 171 out:
 172         btrfs_free_path(path);
 173
 174         return ret;
 175 }
 176
 177 int btrfs_del_inode_ref(struct btrfs_trans_handle *trans,
 178                         struct btrfs_root *root, const struct fscrypt_str *name,
 179                         u64 inode_objectid, u64 ref_objectid, u64 *index)
 180 {
 181         struct btrfs_path *path;
 182         struct btrfs_key key;
 183         struct btrfs_inode_ref *ref;
 184         struct extent_buffer *leaf;
 185         unsigned long ptr;
 186         unsigned long item_start;
 187         u32 item_size;
 188         u32 sub_item_len;
 189         int ret;
 190         int search_ext_refs = 0;
 191         int del_len = name->len + sizeof(*ref);
 192
 193         key.objectid = inode_objectid;
 194         key.offset = ref_objectid;
 195         key.type = BTRFS_INODE_REF_KEY;
 196
 197         path = btrfs_alloc_path();
 198         if (!path)
 199                 return -ENOMEM;
 200
 201         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 202         if (ret > 0) {
 203                 ret = -ENOENT;
 204                 search_ext_refs = 1;
 205                 goto out;
 206         } else if (ret < 0) {
 207                 goto out;
 208         }
 209
 210         ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0], name);
 211         if (!ref) {
 212                 ret = -ENOENT;
 213                 search_ext_refs = 1;
 214                 goto out;
 215         }
 216         leaf = path->nodes[0];
 217         item_size = btrfs_item_size(leaf, path->slots[0]);
 218
 219         if (index)
 220                 *index = btrfs_inode_ref_index(leaf, ref);
 221
 222         if (del_len == item_size) {
 223                 ret = btrfs_del_item(trans, root, path);
 224                 goto out;
 225         }
 226         ptr = (unsigned long)ref;
 227         sub_item_len = name->len + sizeof(*ref);
 228         item_start = btrfs_item_ptr_offset(leaf, path->slots[0]);
 229         memmove_extent_buffer(leaf, ptr, ptr + sub_item_len,
 230                               item_size - (ptr + sub_item_len - item_start));
 231         btrfs_truncate_item(trans, path, item_size - sub_item_len, 1);
 232 out:
 233         btrfs_free_path(path);
 234
 235         if (search_ext_refs) {
 236                 /*
 237                  * No refs were found, or we could not find the
 238                  * name in our ref array. Find and remove the extended
 239                  * inode ref then.
 240                  */
 241                 return btrfs_del_inode_extref(trans, root, name,
 242                                               inode_objectid, ref_objectid, index);
 243         }
 244
 245         return ret;
 246 }
 247
 248 /*
 249  * Insert an extended inode ref into a tree.
 250  *
 251  * The caller must have checked against BTRFS_LINK_MAX already.
 252  */
 253 static int btrfs_insert_inode_extref(struct btrfs_trans_handle *trans,
 254                                      struct btrfs_root *root,
 255                                      const struct fscrypt_str *name,
 256                                      u64 inode_objectid, u64 ref_objectid,
 257                                      u64 index)
 258 {
 259         struct btrfs_inode_extref *extref;
 260         int ret;
 261         int ins_len = name->len + sizeof(*extref);
 262         unsigned long ptr;
 263         struct btrfs_path *path;
 264         struct btrfs_key key;
 265         struct extent_buffer *leaf;
 266
 267         key.objectid = inode_objectid;
 268         key.type = BTRFS_INODE_EXTREF_KEY;
 269         key.offset = btrfs_extref_hash(ref_objectid, name->name, name->len);
 270
 271         path = btrfs_alloc_path();
 272         if (!path)
 273                 return -ENOMEM;
 274
 275         ret = btrfs_insert_empty_item(trans, root, path, &key,
 276                                       ins_len);
 277         if (ret == -EEXIST) {
 278                 if (btrfs_find_name_in_ext_backref(path->nodes[0],
 279                                                    path->slots[0],
 280                                                    ref_objectid,
 281                                                    name))
 282                         goto out;
 283
 284                 btrfs_extend_item(trans, path, ins_len);
 285                 ret = 0;
 286         }
 287         if (ret < 0)
 288                 goto out;
 289
 290         leaf = path->nodes[0];
 291         ptr = (unsigned long)btrfs_item_ptr(leaf, path->slots[0], char);
 292         ptr += btrfs_item_size(leaf, path->slots[0]) - ins_len;
 293         extref = (struct btrfs_inode_extref *)ptr;
 294
 295         btrfs_set_inode_extref_name_len(path->nodes[0], extref, name->len);
 296         btrfs_set_inode_extref_index(path->nodes[0], extref, index);
 297         btrfs_set_inode_extref_parent(path->nodes[0], extref, ref_objectid);
 298
 299         ptr = (unsigned long)&extref->name;
 300         write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
 301         btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 302
 303 out:
 304         btrfs_free_path(path);
 305         return ret;
 306 }
 307
 308 /* Will return 0, -ENOMEM, -EMLINK, or -EEXIST or anything from the CoW path */
 309 int btrfs_insert_inode_ref(struct btrfs_trans_handle *trans,
 310                            struct btrfs_root *root, const struct fscrypt_str *name,
 311                            u64 inode_objectid, u64 ref_objectid, u64 index)
 312 {
 313         struct btrfs_fs_info *fs_info = root->fs_info;
 314         struct btrfs_path *path;
 315         struct btrfs_key key;
 316         struct btrfs_inode_ref *ref;
 317         unsigned long ptr;
 318         int ret;
 319         int ins_len = name->len + sizeof(*ref);
 320
 321         key.objectid = inode_objectid;
 322         key.offset = ref_objectid;
 323         key.type = BTRFS_INODE_REF_KEY;
 324
 325         path = btrfs_alloc_path();
 326         if (!path)
 327                 return -ENOMEM;
 328
 329         path->skip_release_on_error = 1;
 330         ret = btrfs_insert_empty_item(trans, root, path, &key,
 331                                       ins_len);
 332         if (ret == -EEXIST) {
 333                 u32 old_size;
 334                 ref = btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
 335                                                  name);
 336                 if (ref)
 337                         goto out;
 338
 339                 old_size = btrfs_item_size(path->nodes[0], path->slots[0]);
 340                 btrfs_extend_item(trans, path, ins_len);
 341                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 342                                      struct btrfs_inode_ref);
 343                 ref = (struct btrfs_inode_ref *)((unsigned long)ref + old_size);
 344                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
 345                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 346                 ptr = (unsigned long)(ref + 1);
 347                 ret = 0;
 348         } else if (ret < 0) {
 349                 if (ret == -EOVERFLOW) {
 350                         if (btrfs_find_name_in_backref(path->nodes[0],
 351                                                        path->slots[0],
 352                                                        name))
 353                                 ret = -EEXIST;
 354                         else
 355                                 ret = -EMLINK;
 356                 }
 357                 goto out;
 358         } else {
 359                 ref = btrfs_item_ptr(path->nodes[0], path->slots[0],
 360                                      struct btrfs_inode_ref);
 361                 btrfs_set_inode_ref_name_len(path->nodes[0], ref, name->len);
 362                 btrfs_set_inode_ref_index(path->nodes[0], ref, index);
 363                 ptr = (unsigned long)(ref + 1);
 364         }
 365         write_extent_buffer(path->nodes[0], name->name, ptr, name->len);
 366         btrfs_mark_buffer_dirty(trans, path->nodes[0]);
 367
 368 out:
 369         btrfs_free_path(path);
 370
 371         if (ret == -EMLINK) {
 372                 struct btrfs_super_block *disk_super = fs_info->super_copy;
 373                 /* We ran out of space in the ref array. Need to
 374                  * add an extended ref. */
 375                 if (btrfs_super_incompat_flags(disk_super)
 376                     & BTRFS_FEATURE_INCOMPAT_EXTENDED_IREF)
 377                         ret = btrfs_insert_inode_extref(trans, root, name,
 378                                                         inode_objectid,
 379                                                         ref_objectid, index);
 380         }
 381
 382         return ret;
 383 }
 384
 385 int btrfs_insert_empty_inode(struct btrfs_trans_handle *trans,
 386                              struct btrfs_root *root,
 387                              struct btrfs_path *path, u64 objectid)
 388 {
 389         struct btrfs_key key;
 390         int ret;
 391         key.objectid = objectid;
 392         key.type = BTRFS_INODE_ITEM_KEY;
 393         key.offset = 0;
 394
 395         ret = btrfs_insert_empty_item(trans, root, path, &key,
 396                                       sizeof(struct btrfs_inode_item));
 397         return ret;
 398 }
 399
 400 int btrfs_lookup_inode(struct btrfs_trans_handle *trans, struct btrfs_root
 401                        *root, struct btrfs_path *path,
 402                        struct btrfs_key *location, int mod)
 403 {
 404         int ins_len = mod < 0 ? -1 : 0;
 405         int cow = mod != 0;
 406         int ret;
 407         int slot;
 408         struct extent_buffer *leaf;
 409         struct btrfs_key found_key;
 410
 411         ret = btrfs_search_slot(trans, root, location, path, ins_len, cow);
 412         if (ret > 0 && location->type == BTRFS_ROOT_ITEM_KEY &&
 413             location->offset == (u64)-1 && path->slots[0] != 0) {
 414                 slot = path->slots[0] - 1;
 415                 leaf = path->nodes[0];
 416                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
 417                 if (found_key.objectid == location->objectid &&
 418                     found_key.type == location->type) {
 419                         path->slots[0]--;
 420                         return 0;
 421                 }
 422         }
 423         return ret;
 424 }
 425
 426 static inline void btrfs_trace_truncate(struct btrfs_inode *inode,
 427                                         struct extent_buffer *leaf,
 428                                         struct btrfs_file_extent_item *fi,
 429                                         u64 offset, int extent_type, int slot)
 430 {
 431         if (!inode)
 432                 return;
 433         if (extent_type == BTRFS_FILE_EXTENT_INLINE)
 434                 trace_btrfs_truncate_show_fi_inline(inode, leaf, fi, slot,
 435                                                     offset);
 436         else
 437                 trace_btrfs_truncate_show_fi_regular(inode, leaf, fi, offset);
 438 }
 439
 440 /*
 441  * Remove inode items from a given root.
 442  *
 443  * @trans:              A transaction handle.
 444  * @root:               The root from which to remove items.
 445  * @inode:              The inode whose items we want to remove.
 446  * @control:            The btrfs_truncate_control to control how and what we
 447  *                      are truncating.
 448  *
 449  * Remove all keys associated with the inode from the given root that have a key
 450  * with a type greater than or equals to @min_type. When @min_type has a value of
 451  * BTRFS_EXTENT_DATA_KEY, only remove file extent items that have an offset value
 452  * greater than or equals to @new_size. If a file extent item that starts before
 453  * @new_size and ends after it is found, its length is adjusted.
 454  *
 455  * Returns: 0 on success, < 0 on error and NEED_TRUNCATE_BLOCK when @min_type is
 456  * BTRFS_EXTENT_DATA_KEY and the caller must truncate the last block.
 457  */
 458 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
 459                                struct btrfs_root *root,
 460                                struct btrfs_truncate_control *control)
 461 {
 462         struct btrfs_fs_info *fs_info = root->fs_info;
 463         struct btrfs_path *path;
 464         struct extent_buffer *leaf;
 465         struct btrfs_file_extent_item *fi;
 466         struct btrfs_key key;
 467         struct btrfs_key found_key;
 468         u64 new_size = control->new_size;
 469         u64 extent_num_bytes = 0;
 470         u64 extent_offset = 0;
 471         u64 item_end = 0;
 472         u32 found_type = (u8)-1;
 473         int del_item;
 474         int pending_del_nr = 0;
 475         int pending_del_slot = 0;
 476         int extent_type = -1;
 477         int ret;
 478         u64 bytes_deleted = 0;
 479         bool be_nice = false;
 480
 481         ASSERT(control->inode || !control->clear_extent_range);
 482         ASSERT(new_size == 0 || control->min_type == BTRFS_EXTENT_DATA_KEY);
 483
 484         control->last_size = new_size;
 485         control->sub_bytes = 0;
 486
 487         /*
 488          * For shareable roots we want to back off from time to time, this turns
 489          * out to be subvolume roots, reloc roots, and data reloc roots.
 490          */
 491         if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
 492                 be_nice = true;
 493
 494         path = btrfs_alloc_path();
 495         if (!path)
 496                 return -ENOMEM;
 497         path->reada = READA_BACK;
 498
 499         key.objectid = control->ino;
 500         key.offset = (u64)-1;
 501         key.type = (u8)-1;
 502
 503 search_again:
 504         /*
 505          * With a 16K leaf size and 128MiB extents, you can actually queue up a
 506          * huge file in a single leaf.  Most of the time that bytes_deleted is
 507          * > 0, it will be huge by the time we get here
 508          */
 509         if (be_nice && bytes_deleted > SZ_32M &&
 510             btrfs_should_end_transaction(trans)) {
 511                 ret = -EAGAIN;
 512                 goto out;
 513         }
 514
 515         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 516         if (ret < 0)
 517                 goto out;
 518
 519         if (ret > 0) {
 520                 ret = 0;
 521                 /* There are no items in the tree for us to truncate, we're done */
 522                 if (path->slots[0] == 0)
 523                         goto out;
 524                 path->slots[0]--;
 525         }
 526
 527         while (1) {
 528                 u64 clear_start = 0, clear_len = 0, extent_start = 0;
 529                 bool refill_delayed_refs_rsv = false;
 530
 531                 fi = NULL;
 532                 leaf = path->nodes[0];
 533                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
 534                 found_type = found_key.type;
 535
 536                 if (found_key.objectid != control->ino)
 537                         break;
 538
 539                 if (found_type < control->min_type)
 540                         break;
 541
 542                 item_end = found_key.offset;
 543                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
 544                         fi = btrfs_item_ptr(leaf, path->slots[0],
 545                                             struct btrfs_file_extent_item);
 546                         extent_type = btrfs_file_extent_type(leaf, fi);
 547                         if (extent_type != BTRFS_FILE_EXTENT_INLINE)
 548                                 item_end +=
 549                                     btrfs_file_extent_num_bytes(leaf, fi);
 550                         else if (extent_type == BTRFS_FILE_EXTENT_INLINE)
 551                                 item_end += btrfs_file_extent_ram_bytes(leaf, fi);
 552
 553                         btrfs_trace_truncate(control->inode, leaf, fi,
 554                                              found_key.offset, extent_type,
 555                                              path->slots[0]);
 556                         item_end--;
 557                 }
 558                 if (found_type > control->min_type) {
 559                         del_item = 1;
 560                 } else {
 561                         if (item_end < new_size)
 562                                 break;
 563                         if (found_key.offset >= new_size)
 564                                 del_item = 1;
 565                         else
 566                                 del_item = 0;
 567                 }
 568
 569                 /* FIXME, shrink the extent if the ref count is only 1 */
 570                 if (found_type != BTRFS_EXTENT_DATA_KEY)
 571                         goto delete;
 572
 573                 control->extents_found++;
 574
 575                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
 576                         u64 num_dec;
 577
 578                         clear_start = found_key.offset;
 579                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
 580                         if (!del_item) {
 581                                 u64 orig_num_bytes =
 582                                         btrfs_file_extent_num_bytes(leaf, fi);
 583                                 extent_num_bytes = ALIGN(new_size -
 584                                                 found_key.offset,
 585                                                 fs_info->sectorsize);
 586                                 clear_start = ALIGN(new_size, fs_info->sectorsize);
 587
 588                                 btrfs_set_file_extent_num_bytes(leaf, fi,
 589                                                          extent_num_bytes);
 590                                 num_dec = (orig_num_bytes - extent_num_bytes);
 591                                 if (extent_start != 0)
 592                                         control->sub_bytes += num_dec;
 593                                 btrfs_mark_buffer_dirty(trans, leaf);
 594                         } else {
 595                                 extent_num_bytes =
 596                                         btrfs_file_extent_disk_num_bytes(leaf, fi);
 597                                 extent_offset = found_key.offset -
 598                                         btrfs_file_extent_offset(leaf, fi);
 599
 600                                 /* FIXME blocksize != 4096 */
 601                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
 602                                 if (extent_start != 0)
 603                                         control->sub_bytes += num_dec;
 604                         }
 605                         clear_len = num_dec;
 606                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 607                         /*
 608                          * We can't truncate inline items that have had
 609                          * special encodings
 610                          */
 611                         if (!del_item &&
 612                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
 613                             btrfs_file_extent_other_encoding(leaf, fi) == 0 &&
 614                             btrfs_file_extent_compression(leaf, fi) == 0) {
 615                                 u32 size = (u32)(new_size - found_key.offset);
 616
 617                                 btrfs_set_file_extent_ram_bytes(leaf, fi, size);
 618                                 size = btrfs_file_extent_calc_inline_size(size);
 619                                 btrfs_truncate_item(trans, path, size, 1);
 620                         } else if (!del_item) {
 621                                 /*
 622                                  * We have to bail so the last_size is set to
 623                                  * just before this extent.
 624                                  */
 625                                 ret = BTRFS_NEED_TRUNCATE_BLOCK;
 626                                 break;
 627                         } else {
 628                                 /*
 629                                  * Inline extents are special, we just treat
 630                                  * them as a full sector worth in the file
 631                                  * extent tree just for simplicity sake.
 632                                  */
 633                                 clear_len = fs_info->sectorsize;
 634                         }
 635
 636                         control->sub_bytes += item_end + 1 - new_size;
 637                 }
 638 delete:
 639                 /*
 640                  * We only want to clear the file extent range if we're
 641                  * modifying the actual inode's mapping, which is just the
 642                  * normal truncate path.
 643                  */
 644                 if (control->clear_extent_range) {
 645                         ret = btrfs_inode_clear_file_extent_range(control->inode,
 646                                                   clear_start, clear_len);
 647                         if (ret) {
 648                                 btrfs_abort_transaction(trans, ret);
 649                                 break;
 650                         }
 651                 }
 652
 653                 if (del_item) {
 654                         ASSERT(!pending_del_nr ||
 655                                ((path->slots[0] + 1) == pending_del_slot));
 656
 657                         control->last_size = found_key.offset;
 658                         if (!pending_del_nr) {
 659                                 /* No pending yet, add ourselves */
 660                                 pending_del_slot = path->slots[0];
 661                                 pending_del_nr = 1;
 662                         } else if (path->slots[0] + 1 == pending_del_slot) {
 663                                 /* Hop on the pending chunk */
 664                                 pending_del_nr++;
 665                                 pending_del_slot = path->slots[0];
 666                         }
 667                 } else {
 668                         control->last_size = new_size;
 669                         break;
 670                 }
 671
 672                 if (del_item && extent_start != 0 && !control->skip_ref_updates) {
 673                         struct btrfs_ref ref = { 0 };
 674
 675                         bytes_deleted += extent_num_bytes;
 676
 677                         btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF,
 678                                         extent_start, extent_num_bytes, 0,
 679                                         root->root_key.objectid);
 680                         btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
 681                                         control->ino, extent_offset,
 682                                         root->root_key.objectid, false);
 683                         ret = btrfs_free_extent(trans, &ref);
 684                         if (ret) {
 685                                 btrfs_abort_transaction(trans, ret);
 686                                 break;
 687                         }
 688                         if (be_nice && btrfs_check_space_for_delayed_refs(fs_info))
 689                                 refill_delayed_refs_rsv = true;
 690                 }
 691
 692                 if (found_type == BTRFS_INODE_ITEM_KEY)
 693                         break;
 694
 695                 if (path->slots[0] == 0 ||
 696                     path->slots[0] != pending_del_slot ||
 697                     refill_delayed_refs_rsv) {
 698                         if (pending_del_nr) {
 699                                 ret = btrfs_del_items(trans, root, path,
 700                                                 pending_del_slot,
 701                                                 pending_del_nr);
 702                                 if (ret) {
 703                                         btrfs_abort_transaction(trans, ret);
 704                                         break;
 705                                 }
 706                                 pending_del_nr = 0;
 707                         }
 708                         btrfs_release_path(path);
 709
 710                         /*
 711                          * We can generate a lot of delayed refs, so we need to
 712                          * throttle every once and a while and make sure we're
 713                          * adding enough space to keep up with the work we are
 714                          * generating.  Since we hold a transaction here we
 715                          * can't flush, and we don't want to FLUSH_LIMIT because
 716                          * we could have generated too many delayed refs to
 717                          * actually allocate, so just bail if we're short and
 718                          * let the normal reservation dance happen higher up.
 719                          */
 720                         if (refill_delayed_refs_rsv) {
 721                                 ret = btrfs_delayed_refs_rsv_refill(fs_info,
 722                                                         BTRFS_RESERVE_NO_FLUSH);
 723                                 if (ret) {
 724                                         ret = -EAGAIN;
 725                                         break;
 726                                 }
 727                         }
 728                         goto search_again;
 729                 } else {
 730                         path->slots[0]--;
 731                 }
 732         }
 733 out:
 734         if (ret >= 0 && pending_del_nr) {
 735                 int err;
 736
 737                 err = btrfs_del_items(trans, root, path, pending_del_slot,
 738                                       pending_del_nr);
 739                 if (err) {
 740                         btrfs_abort_transaction(trans, err);
 741                         ret = err;
 742                 }
 743         }
 744
 745         ASSERT(control->last_size >= new_size);
 746         if (!ret && control->last_size > new_size)
 747                 control->last_size = new_size;
 748
 749         btrfs_free_path(path);
 750         return ret;
 751 }