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