1 // SPDX-License-Identifier: GPL-2.0 2 3 #include "misc.h" 4 #include "ctree.h" 5 #include "space-info.h" 6 #include "sysfs.h" 7 #include "volumes.h" 8 #include "free-space-cache.h" 9 #include "ordered-data.h" 10 #include "transaction.h" 11 #include "block-group.h" 12 13 /* 14 * HOW DOES SPACE RESERVATION WORK 15 * 16 * If you want to know about delalloc specifically, there is a separate comment 17 * for that with the delalloc code. This comment is about how the whole system 18 * works generally. 19 * 20 * BASIC CONCEPTS 21 * 22 * 1) space_info. This is the ultimate arbiter of how much space we can use. 23 * There's a description of the bytes_ fields with the struct declaration, 24 * refer to that for specifics on each field. Suffice it to say that for 25 * reservations we care about total_bytes - SUM(space_info->bytes_) when 26 * determining if there is space to make an allocation. There is a space_info 27 * for METADATA, SYSTEM, and DATA areas. 28 * 29 * 2) block_rsv's. These are basically buckets for every different type of 30 * metadata reservation we have. You can see the comment in the block_rsv 31 * code on the rules for each type, but generally block_rsv->reserved is how 32 * much space is accounted for in space_info->bytes_may_use. 33 * 34 * 3) btrfs_calc*_size. These are the worst case calculations we used based 35 * on the number of items we will want to modify. We have one for changing 36 * items, and one for inserting new items. Generally we use these helpers to 37 * determine the size of the block reserves, and then use the actual bytes 38 * values to adjust the space_info counters. 39 * 40 * MAKING RESERVATIONS, THE NORMAL CASE 41 * 42 * We call into either btrfs_reserve_data_bytes() or 43 * btrfs_reserve_metadata_bytes(), depending on which we're looking for, with 44 * num_bytes we want to reserve. 45 * 46 * ->reserve 47 * space_info->bytes_may_reserve += num_bytes 48 * 49 * ->extent allocation 50 * Call btrfs_add_reserved_bytes() which does 51 * space_info->bytes_may_reserve -= num_bytes 52 * space_info->bytes_reserved += extent_bytes 53 * 54 * ->insert reference 55 * Call btrfs_update_block_group() which does 56 * space_info->bytes_reserved -= extent_bytes 57 * space_info->bytes_used += extent_bytes 58 * 59 * MAKING RESERVATIONS, FLUSHING NORMALLY (non-priority) 60 * 61 * Assume we are unable to simply make the reservation because we do not have 62 * enough space 63 * 64 * -> __reserve_bytes 65 * create a reserve_ticket with ->bytes set to our reservation, add it to 66 * the tail of space_info->tickets, kick async flush thread 67 * 68 * ->handle_reserve_ticket 69 * wait on ticket->wait for ->bytes to be reduced to 0, or ->error to be set 70 * on the ticket. 71 * 72 * -> btrfs_async_reclaim_metadata_space/btrfs_async_reclaim_data_space 73 * Flushes various things attempting to free up space. 74 * 75 * -> btrfs_try_granting_tickets() 76 * This is called by anything that either subtracts space from 77 * space_info->bytes_may_use, ->bytes_pinned, etc, or adds to the 78 * space_info->total_bytes. This loops through the ->priority_tickets and 79 * then the ->tickets list checking to see if the reservation can be 80 * completed. If it can the space is added to space_info->bytes_may_use and 81 * the ticket is woken up. 82 * 83 * -> ticket wakeup 84 * Check if ->bytes == 0, if it does we got our reservation and we can carry 85 * on, if not return the appropriate error (ENOSPC, but can be EINTR if we 86 * were interrupted.) 87 * 88 * MAKING RESERVATIONS, FLUSHING HIGH PRIORITY 89 * 90 * Same as the above, except we add ourselves to the 91 * space_info->priority_tickets, and we do not use ticket->wait, we simply 92 * call flush_space() ourselves for the states that are safe for us to call 93 * without deadlocking and hope for the best. 94 * 95 * THE FLUSHING STATES 96 * 97 * Generally speaking we will have two cases for each state, a "nice" state 98 * and a "ALL THE THINGS" state. In btrfs we delay a lot of work in order to 99 * reduce the locking over head on the various trees, and even to keep from 100 * doing any work at all in the case of delayed refs. Each of these delayed 101 * things however hold reservations, and so letting them run allows us to 102 * reclaim space so we can make new reservations. 103 * 104 * FLUSH_DELAYED_ITEMS 105 * Every inode has a delayed item to update the inode. Take a simple write 106 * for example, we would update the inode item at write time to update the 107 * mtime, and then again at finish_ordered_io() time in order to update the 108 * isize or bytes. We keep these delayed items to coalesce these operations 109 * into a single operation done on demand. These are an easy way to reclaim 110 * metadata space. 111 * 112 * FLUSH_DELALLOC 113 * Look at the delalloc comment to get an idea of how much space is reserved 114 * for delayed allocation. We can reclaim some of this space simply by 115 * running delalloc, but usually we need to wait for ordered extents to 116 * reclaim the bulk of this space. 117 * 118 * FLUSH_DELAYED_REFS 119 * We have a block reserve for the outstanding delayed refs space, and every 120 * delayed ref operation holds a reservation. Running these is a quick way 121 * to reclaim space, but we want to hold this until the end because COW can 122 * churn a lot and we can avoid making some extent tree modifications if we 123 * are able to delay for as long as possible. 124 * 125 * ALLOC_CHUNK 126 * We will skip this the first time through space reservation, because of 127 * overcommit and we don't want to have a lot of useless metadata space when 128 * our worst case reservations will likely never come true. 129 * 130 * RUN_DELAYED_IPUTS 131 * If we're freeing inodes we're likely freeing checksums, file extent 132 * items, and extent tree items. Loads of space could be freed up by these 133 * operations, however they won't be usable until the transaction commits. 134 * 135 * COMMIT_TRANS 136 * may_commit_transaction() is the ultimate arbiter on whether we commit the 137 * transaction or not. In order to avoid constantly churning we do all the 138 * above flushing first and then commit the transaction as the last resort. 139 * However we need to take into account things like pinned space that would 140 * be freed, plus any delayed work we may not have gotten rid of in the case 141 * of metadata. 142 * 143 * OVERCOMMIT 144 * 145 * Because we hold so many reservations for metadata we will allow you to 146 * reserve more space than is currently free in the currently allocate 147 * metadata space. This only happens with metadata, data does not allow 148 * overcommitting. 149 * 150 * You can see the current logic for when we allow overcommit in 151 * btrfs_can_overcommit(), but it only applies to unallocated space. If there 152 * is no unallocated space to be had, all reservations are kept within the 153 * free space in the allocated metadata chunks. 154 * 155 * Because of overcommitting, you generally want to use the 156 * btrfs_can_overcommit() logic for metadata allocations, as it does the right 157 * thing with or without extra unallocated space. 158 */ 159 160 u64 __pure btrfs_space_info_used(struct btrfs_space_info *s_info, 161 bool may_use_included) 162 { 163 ASSERT(s_info); 164 return s_info->bytes_used + s_info->bytes_reserved + 165 s_info->bytes_pinned + s_info->bytes_readonly + 166 (may_use_included ? s_info->bytes_may_use : 0); 167 } 168 169 /* 170 * after adding space to the filesystem, we need to clear the full flags 171 * on all the space infos. 172 */ 173 void btrfs_clear_space_info_full(struct btrfs_fs_info *info) 174 { 175 struct list_head *head = &info->space_info; 176 struct btrfs_space_info *found; 177 178 list_for_each_entry(found, head, list) 179 found->full = 0; 180 } 181 182 static int create_space_info(struct btrfs_fs_info *info, u64 flags) 183 { 184 185 struct btrfs_space_info *space_info; 186 int i; 187 int ret; 188 189 space_info = kzalloc(sizeof(*space_info), GFP_NOFS); 190 if (!space_info) 191 return -ENOMEM; 192 193 ret = percpu_counter_init(&space_info->total_bytes_pinned, 0, 194 GFP_KERNEL); 195 if (ret) { 196 kfree(space_info); 197 return ret; 198 } 199 200 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) 201 INIT_LIST_HEAD(&space_info->block_groups[i]); 202 init_rwsem(&space_info->groups_sem); 203 spin_lock_init(&space_info->lock); 204 space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK; 205 space_info->force_alloc = CHUNK_ALLOC_NO_FORCE; 206 INIT_LIST_HEAD(&space_info->ro_bgs); 207 INIT_LIST_HEAD(&space_info->tickets); 208 INIT_LIST_HEAD(&space_info->priority_tickets); 209 210 ret = btrfs_sysfs_add_space_info_type(info, space_info); 211 if (ret) 212 return ret; 213 214 list_add(&space_info->list, &info->space_info); 215 if (flags & BTRFS_BLOCK_GROUP_DATA) 216 info->data_sinfo = space_info; 217 218 return ret; 219 } 220 221 int btrfs_init_space_info(struct btrfs_fs_info *fs_info) 222 { 223 struct btrfs_super_block *disk_super; 224 u64 features; 225 u64 flags; 226 int mixed = 0; 227 int ret; 228 229 disk_super = fs_info->super_copy; 230 if (!btrfs_super_root(disk_super)) 231 return -EINVAL; 232 233 features = btrfs_super_incompat_flags(disk_super); 234 if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) 235 mixed = 1; 236 237 flags = BTRFS_BLOCK_GROUP_SYSTEM; 238 ret = create_space_info(fs_info, flags); 239 if (ret) 240 goto out; 241 242 if (mixed) { 243 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA; 244 ret = create_space_info(fs_info, flags); 245 } else { 246 flags = BTRFS_BLOCK_GROUP_METADATA; 247 ret = create_space_info(fs_info, flags); 248 if (ret) 249 goto out; 250 251 flags = BTRFS_BLOCK_GROUP_DATA; 252 ret = create_space_info(fs_info, flags); 253 } 254 out: 255 return ret; 256 } 257 258 void btrfs_update_space_info(struct btrfs_fs_info *info, u64 flags, 259 u64 total_bytes, u64 bytes_used, 260 u64 bytes_readonly, 261 struct btrfs_space_info **space_info) 262 { 263 struct btrfs_space_info *found; 264 int factor; 265 266 factor = btrfs_bg_type_to_factor(flags); 267 268 found = btrfs_find_space_info(info, flags); 269 ASSERT(found); 270 spin_lock(&found->lock); 271 found->total_bytes += total_bytes; 272 found->disk_total += total_bytes * factor; 273 found->bytes_used += bytes_used; 274 found->disk_used += bytes_used * factor; 275 found->bytes_readonly += bytes_readonly; 276 if (total_bytes > 0) 277 found->full = 0; 278 btrfs_try_granting_tickets(info, found); 279 spin_unlock(&found->lock); 280 *space_info = found; 281 } 282 283 struct btrfs_space_info *btrfs_find_space_info(struct btrfs_fs_info *info, 284 u64 flags) 285 { 286 struct list_head *head = &info->space_info; 287 struct btrfs_space_info *found; 288 289 flags &= BTRFS_BLOCK_GROUP_TYPE_MASK; 290 291 list_for_each_entry(found, head, list) { 292 if (found->flags & flags) 293 return found; 294 } 295 return NULL; 296 } 297 298 static u64 calc_available_free_space(struct btrfs_fs_info *fs_info, 299 struct btrfs_space_info *space_info, 300 enum btrfs_reserve_flush_enum flush) 301 { 302 u64 profile; 303 u64 avail; 304 int factor; 305 306 if (space_info->flags & BTRFS_BLOCK_GROUP_SYSTEM) 307 profile = btrfs_system_alloc_profile(fs_info); 308 else 309 profile = btrfs_metadata_alloc_profile(fs_info); 310 311 avail = atomic64_read(&fs_info->free_chunk_space); 312 313 /* 314 * If we have dup, raid1 or raid10 then only half of the free 315 * space is actually usable. For raid56, the space info used 316 * doesn't include the parity drive, so we don't have to 317 * change the math 318 */ 319 factor = btrfs_bg_type_to_factor(profile); 320 avail = div_u64(avail, factor); 321 322 /* 323 * If we aren't flushing all things, let us overcommit up to 324 * 1/2th of the space. If we can flush, don't let us overcommit 325 * too much, let it overcommit up to 1/8 of the space. 326 */ 327 if (flush == BTRFS_RESERVE_FLUSH_ALL) 328 avail >>= 3; 329 else 330 avail >>= 1; 331 return avail; 332 } 333 334 int btrfs_can_overcommit(struct btrfs_fs_info *fs_info, 335 struct btrfs_space_info *space_info, u64 bytes, 336 enum btrfs_reserve_flush_enum flush) 337 { 338 u64 avail; 339 u64 used; 340 341 /* Don't overcommit when in mixed mode */ 342 if (space_info->flags & BTRFS_BLOCK_GROUP_DATA) 343 return 0; 344 345 used = btrfs_space_info_used(space_info, true); 346 avail = calc_available_free_space(fs_info, space_info, flush); 347 348 if (used + bytes < space_info->total_bytes + avail) 349 return 1; 350 return 0; 351 } 352 353 static void remove_ticket(struct btrfs_space_info *space_info, 354 struct reserve_ticket *ticket) 355 { 356 if (!list_empty(&ticket->list)) { 357 list_del_init(&ticket->list); 358 ASSERT(space_info->reclaim_size >= ticket->bytes); 359 space_info->reclaim_size -= ticket->bytes; 360 } 361 } 362 363 /* 364 * This is for space we already have accounted in space_info->bytes_may_use, so 365 * basically when we're returning space from block_rsv's. 366 */ 367 void btrfs_try_granting_tickets(struct btrfs_fs_info *fs_info, 368 struct btrfs_space_info *space_info) 369 { 370 struct list_head *head; 371 enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH; 372 373 lockdep_assert_held(&space_info->lock); 374 375 head = &space_info->priority_tickets; 376 again: 377 while (!list_empty(head)) { 378 struct reserve_ticket *ticket; 379 u64 used = btrfs_space_info_used(space_info, true); 380 381 ticket = list_first_entry(head, struct reserve_ticket, list); 382 383 /* Check and see if our ticket can be satisified now. */ 384 if ((used + ticket->bytes <= space_info->total_bytes) || 385 btrfs_can_overcommit(fs_info, space_info, ticket->bytes, 386 flush)) { 387 btrfs_space_info_update_bytes_may_use(fs_info, 388 space_info, 389 ticket->bytes); 390 remove_ticket(space_info, ticket); 391 ticket->bytes = 0; 392 space_info->tickets_id++; 393 wake_up(&ticket->wait); 394 } else { 395 break; 396 } 397 } 398 399 if (head == &space_info->priority_tickets) { 400 head = &space_info->tickets; 401 flush = BTRFS_RESERVE_FLUSH_ALL; 402 goto again; 403 } 404 } 405 406 #define DUMP_BLOCK_RSV(fs_info, rsv_name) \ 407 do { \ 408 struct btrfs_block_rsv *__rsv = &(fs_info)->rsv_name; \ 409 spin_lock(&__rsv->lock); \ 410 btrfs_info(fs_info, #rsv_name ": size %llu reserved %llu", \ 411 __rsv->size, __rsv->reserved); \ 412 spin_unlock(&__rsv->lock); \ 413 } while (0) 414 415 static void __btrfs_dump_space_info(struct btrfs_fs_info *fs_info, 416 struct btrfs_space_info *info) 417 { 418 lockdep_assert_held(&info->lock); 419 420 btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull", 421 info->flags, 422 info->total_bytes - btrfs_space_info_used(info, true), 423 info->full ? "" : "not "); 424 btrfs_info(fs_info, 425 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu", 426 info->total_bytes, info->bytes_used, info->bytes_pinned, 427 info->bytes_reserved, info->bytes_may_use, 428 info->bytes_readonly); 429 430 DUMP_BLOCK_RSV(fs_info, global_block_rsv); 431 DUMP_BLOCK_RSV(fs_info, trans_block_rsv); 432 DUMP_BLOCK_RSV(fs_info, chunk_block_rsv); 433 DUMP_BLOCK_RSV(fs_info, delayed_block_rsv); 434 DUMP_BLOCK_RSV(fs_info, delayed_refs_rsv); 435 436 } 437 438 void btrfs_dump_space_info(struct btrfs_fs_info *fs_info, 439 struct btrfs_space_info *info, u64 bytes, 440 int dump_block_groups) 441 { 442 struct btrfs_block_group *cache; 443 int index = 0; 444 445 spin_lock(&info->lock); 446 __btrfs_dump_space_info(fs_info, info); 447 spin_unlock(&info->lock); 448 449 if (!dump_block_groups) 450 return; 451 452 down_read(&info->groups_sem); 453 again: 454 list_for_each_entry(cache, &info->block_groups[index], list) { 455 spin_lock(&cache->lock); 456 btrfs_info(fs_info, 457 "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s", 458 cache->start, cache->length, cache->used, cache->pinned, 459 cache->reserved, cache->ro ? "[readonly]" : ""); 460 spin_unlock(&cache->lock); 461 btrfs_dump_free_space(cache, bytes); 462 } 463 if (++index < BTRFS_NR_RAID_TYPES) 464 goto again; 465 up_read(&info->groups_sem); 466 } 467 468 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info, 469 u64 to_reclaim) 470 { 471 u64 bytes; 472 u64 nr; 473 474 bytes = btrfs_calc_insert_metadata_size(fs_info, 1); 475 nr = div64_u64(to_reclaim, bytes); 476 if (!nr) 477 nr = 1; 478 return nr; 479 } 480 481 #define EXTENT_SIZE_PER_ITEM SZ_256K 482 483 /* 484 * shrink metadata reservation for delalloc 485 */ 486 static void shrink_delalloc(struct btrfs_fs_info *fs_info, 487 struct btrfs_space_info *space_info, 488 u64 to_reclaim, bool wait_ordered) 489 { 490 struct btrfs_trans_handle *trans; 491 u64 delalloc_bytes; 492 u64 dio_bytes; 493 u64 items; 494 long time_left; 495 int loops; 496 497 /* Calc the number of the pages we need flush for space reservation */ 498 if (to_reclaim == U64_MAX) { 499 items = U64_MAX; 500 } else { 501 /* 502 * to_reclaim is set to however much metadata we need to 503 * reclaim, but reclaiming that much data doesn't really track 504 * exactly, so increase the amount to reclaim by 2x in order to 505 * make sure we're flushing enough delalloc to hopefully reclaim 506 * some metadata reservations. 507 */ 508 items = calc_reclaim_items_nr(fs_info, to_reclaim) * 2; 509 to_reclaim = items * EXTENT_SIZE_PER_ITEM; 510 } 511 512 trans = (struct btrfs_trans_handle *)current->journal_info; 513 514 delalloc_bytes = percpu_counter_sum_positive( 515 &fs_info->delalloc_bytes); 516 dio_bytes = percpu_counter_sum_positive(&fs_info->dio_bytes); 517 if (delalloc_bytes == 0 && dio_bytes == 0) { 518 if (trans) 519 return; 520 if (wait_ordered) 521 btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1); 522 return; 523 } 524 525 /* 526 * If we are doing more ordered than delalloc we need to just wait on 527 * ordered extents, otherwise we'll waste time trying to flush delalloc 528 * that likely won't give us the space back we need. 529 */ 530 if (dio_bytes > delalloc_bytes) 531 wait_ordered = true; 532 533 loops = 0; 534 while ((delalloc_bytes || dio_bytes) && loops < 3) { 535 u64 temp = min(delalloc_bytes, to_reclaim) >> PAGE_SHIFT; 536 long nr_pages = min_t(u64, temp, LONG_MAX); 537 538 btrfs_start_delalloc_roots(fs_info, nr_pages, true); 539 540 loops++; 541 if (wait_ordered && !trans) { 542 btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1); 543 } else { 544 time_left = schedule_timeout_killable(1); 545 if (time_left) 546 break; 547 } 548 549 spin_lock(&space_info->lock); 550 if (list_empty(&space_info->tickets) && 551 list_empty(&space_info->priority_tickets)) { 552 spin_unlock(&space_info->lock); 553 break; 554 } 555 spin_unlock(&space_info->lock); 556 557 delalloc_bytes = percpu_counter_sum_positive( 558 &fs_info->delalloc_bytes); 559 dio_bytes = percpu_counter_sum_positive(&fs_info->dio_bytes); 560 } 561 } 562 563 /** 564 * Possibly commit the transaction if its ok to 565 * 566 * @fs_info: the filesystem 567 * @space_info: space_info we are checking for commit, either data or metadata 568 * 569 * This will check to make sure that committing the transaction will actually 570 * get us somewhere and then commit the transaction if it does. Otherwise it 571 * will return -ENOSPC. 572 */ 573 static int may_commit_transaction(struct btrfs_fs_info *fs_info, 574 struct btrfs_space_info *space_info) 575 { 576 struct reserve_ticket *ticket = NULL; 577 struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv; 578 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv; 579 struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv; 580 struct btrfs_trans_handle *trans; 581 u64 reclaim_bytes = 0; 582 u64 bytes_needed = 0; 583 u64 cur_free_bytes = 0; 584 585 trans = (struct btrfs_trans_handle *)current->journal_info; 586 if (trans) 587 return -EAGAIN; 588 589 spin_lock(&space_info->lock); 590 cur_free_bytes = btrfs_space_info_used(space_info, true); 591 if (cur_free_bytes < space_info->total_bytes) 592 cur_free_bytes = space_info->total_bytes - cur_free_bytes; 593 else 594 cur_free_bytes = 0; 595 596 if (!list_empty(&space_info->priority_tickets)) 597 ticket = list_first_entry(&space_info->priority_tickets, 598 struct reserve_ticket, list); 599 else if (!list_empty(&space_info->tickets)) 600 ticket = list_first_entry(&space_info->tickets, 601 struct reserve_ticket, list); 602 if (ticket) 603 bytes_needed = ticket->bytes; 604 605 if (bytes_needed > cur_free_bytes) 606 bytes_needed -= cur_free_bytes; 607 else 608 bytes_needed = 0; 609 spin_unlock(&space_info->lock); 610 611 if (!bytes_needed) 612 return 0; 613 614 trans = btrfs_join_transaction(fs_info->extent_root); 615 if (IS_ERR(trans)) 616 return PTR_ERR(trans); 617 618 /* 619 * See if there is enough pinned space to make this reservation, or if 620 * we have block groups that are going to be freed, allowing us to 621 * possibly do a chunk allocation the next loop through. 622 */ 623 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &trans->transaction->flags) || 624 __percpu_counter_compare(&space_info->total_bytes_pinned, 625 bytes_needed, 626 BTRFS_TOTAL_BYTES_PINNED_BATCH) >= 0) 627 goto commit; 628 629 /* 630 * See if there is some space in the delayed insertion reserve for this 631 * reservation. If the space_info's don't match (like for DATA or 632 * SYSTEM) then just go enospc, reclaiming this space won't recover any 633 * space to satisfy those reservations. 634 */ 635 if (space_info != delayed_rsv->space_info) 636 goto enospc; 637 638 spin_lock(&delayed_rsv->lock); 639 reclaim_bytes += delayed_rsv->reserved; 640 spin_unlock(&delayed_rsv->lock); 641 642 spin_lock(&delayed_refs_rsv->lock); 643 reclaim_bytes += delayed_refs_rsv->reserved; 644 spin_unlock(&delayed_refs_rsv->lock); 645 646 spin_lock(&trans_rsv->lock); 647 reclaim_bytes += trans_rsv->reserved; 648 spin_unlock(&trans_rsv->lock); 649 650 if (reclaim_bytes >= bytes_needed) 651 goto commit; 652 bytes_needed -= reclaim_bytes; 653 654 if (__percpu_counter_compare(&space_info->total_bytes_pinned, 655 bytes_needed, 656 BTRFS_TOTAL_BYTES_PINNED_BATCH) < 0) 657 goto enospc; 658 659 commit: 660 return btrfs_commit_transaction(trans); 661 enospc: 662 btrfs_end_transaction(trans); 663 return -ENOSPC; 664 } 665 666 /* 667 * Try to flush some data based on policy set by @state. This is only advisory 668 * and may fail for various reasons. The caller is supposed to examine the 669 * state of @space_info to detect the outcome. 670 */ 671 static void flush_space(struct btrfs_fs_info *fs_info, 672 struct btrfs_space_info *space_info, u64 num_bytes, 673 int state) 674 { 675 struct btrfs_root *root = fs_info->extent_root; 676 struct btrfs_trans_handle *trans; 677 int nr; 678 int ret = 0; 679 680 switch (state) { 681 case FLUSH_DELAYED_ITEMS_NR: 682 case FLUSH_DELAYED_ITEMS: 683 if (state == FLUSH_DELAYED_ITEMS_NR) 684 nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2; 685 else 686 nr = -1; 687 688 trans = btrfs_join_transaction(root); 689 if (IS_ERR(trans)) { 690 ret = PTR_ERR(trans); 691 break; 692 } 693 ret = btrfs_run_delayed_items_nr(trans, nr); 694 btrfs_end_transaction(trans); 695 break; 696 case FLUSH_DELALLOC: 697 case FLUSH_DELALLOC_WAIT: 698 shrink_delalloc(fs_info, space_info, num_bytes, 699 state == FLUSH_DELALLOC_WAIT); 700 break; 701 case FLUSH_DELAYED_REFS_NR: 702 case FLUSH_DELAYED_REFS: 703 trans = btrfs_join_transaction(root); 704 if (IS_ERR(trans)) { 705 ret = PTR_ERR(trans); 706 break; 707 } 708 if (state == FLUSH_DELAYED_REFS_NR) 709 nr = calc_reclaim_items_nr(fs_info, num_bytes); 710 else 711 nr = 0; 712 btrfs_run_delayed_refs(trans, nr); 713 btrfs_end_transaction(trans); 714 break; 715 case ALLOC_CHUNK: 716 case ALLOC_CHUNK_FORCE: 717 trans = btrfs_join_transaction(root); 718 if (IS_ERR(trans)) { 719 ret = PTR_ERR(trans); 720 break; 721 } 722 ret = btrfs_chunk_alloc(trans, 723 btrfs_get_alloc_profile(fs_info, space_info->flags), 724 (state == ALLOC_CHUNK) ? CHUNK_ALLOC_NO_FORCE : 725 CHUNK_ALLOC_FORCE); 726 btrfs_end_transaction(trans); 727 if (ret > 0 || ret == -ENOSPC) 728 ret = 0; 729 break; 730 case RUN_DELAYED_IPUTS: 731 /* 732 * If we have pending delayed iputs then we could free up a 733 * bunch of pinned space, so make sure we run the iputs before 734 * we do our pinned bytes check below. 735 */ 736 btrfs_run_delayed_iputs(fs_info); 737 btrfs_wait_on_delayed_iputs(fs_info); 738 break; 739 case COMMIT_TRANS: 740 ret = may_commit_transaction(fs_info, space_info); 741 break; 742 default: 743 ret = -ENOSPC; 744 break; 745 } 746 747 trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state, 748 ret); 749 return; 750 } 751 752 static inline u64 753 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info, 754 struct btrfs_space_info *space_info) 755 { 756 u64 used; 757 u64 avail; 758 u64 expected; 759 u64 to_reclaim = space_info->reclaim_size; 760 761 lockdep_assert_held(&space_info->lock); 762 763 avail = calc_available_free_space(fs_info, space_info, 764 BTRFS_RESERVE_FLUSH_ALL); 765 used = btrfs_space_info_used(space_info, true); 766 767 /* 768 * We may be flushing because suddenly we have less space than we had 769 * before, and now we're well over-committed based on our current free 770 * space. If that's the case add in our overage so we make sure to put 771 * appropriate pressure on the flushing state machine. 772 */ 773 if (space_info->total_bytes + avail < used) 774 to_reclaim += used - (space_info->total_bytes + avail); 775 776 if (to_reclaim) 777 return to_reclaim; 778 779 to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M); 780 if (btrfs_can_overcommit(fs_info, space_info, to_reclaim, 781 BTRFS_RESERVE_FLUSH_ALL)) 782 return 0; 783 784 used = btrfs_space_info_used(space_info, true); 785 786 if (btrfs_can_overcommit(fs_info, space_info, SZ_1M, 787 BTRFS_RESERVE_FLUSH_ALL)) 788 expected = div_factor_fine(space_info->total_bytes, 95); 789 else 790 expected = div_factor_fine(space_info->total_bytes, 90); 791 792 if (used > expected) 793 to_reclaim = used - expected; 794 else 795 to_reclaim = 0; 796 to_reclaim = min(to_reclaim, space_info->bytes_may_use + 797 space_info->bytes_reserved); 798 return to_reclaim; 799 } 800 801 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info, 802 struct btrfs_space_info *space_info, 803 u64 used) 804 { 805 u64 thresh = div_factor_fine(space_info->total_bytes, 98); 806 807 /* If we're just plain full then async reclaim just slows us down. */ 808 if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh) 809 return 0; 810 811 if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info)) 812 return 0; 813 814 return (used >= thresh && !btrfs_fs_closing(fs_info) && 815 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state)); 816 } 817 818 static bool steal_from_global_rsv(struct btrfs_fs_info *fs_info, 819 struct btrfs_space_info *space_info, 820 struct reserve_ticket *ticket) 821 { 822 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; 823 u64 min_bytes; 824 825 if (global_rsv->space_info != space_info) 826 return false; 827 828 spin_lock(&global_rsv->lock); 829 min_bytes = div_factor(global_rsv->size, 1); 830 if (global_rsv->reserved < min_bytes + ticket->bytes) { 831 spin_unlock(&global_rsv->lock); 832 return false; 833 } 834 global_rsv->reserved -= ticket->bytes; 835 remove_ticket(space_info, ticket); 836 ticket->bytes = 0; 837 wake_up(&ticket->wait); 838 space_info->tickets_id++; 839 if (global_rsv->reserved < global_rsv->size) 840 global_rsv->full = 0; 841 spin_unlock(&global_rsv->lock); 842 843 return true; 844 } 845 846 /* 847 * maybe_fail_all_tickets - we've exhausted our flushing, start failing tickets 848 * @fs_info - fs_info for this fs 849 * @space_info - the space info we were flushing 850 * 851 * We call this when we've exhausted our flushing ability and haven't made 852 * progress in satisfying tickets. The reservation code handles tickets in 853 * order, so if there is a large ticket first and then smaller ones we could 854 * very well satisfy the smaller tickets. This will attempt to wake up any 855 * tickets in the list to catch this case. 856 * 857 * This function returns true if it was able to make progress by clearing out 858 * other tickets, or if it stumbles across a ticket that was smaller than the 859 * first ticket. 860 */ 861 static bool maybe_fail_all_tickets(struct btrfs_fs_info *fs_info, 862 struct btrfs_space_info *space_info) 863 { 864 struct reserve_ticket *ticket; 865 u64 tickets_id = space_info->tickets_id; 866 u64 first_ticket_bytes = 0; 867 868 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) { 869 btrfs_info(fs_info, "cannot satisfy tickets, dumping space info"); 870 __btrfs_dump_space_info(fs_info, space_info); 871 } 872 873 while (!list_empty(&space_info->tickets) && 874 tickets_id == space_info->tickets_id) { 875 ticket = list_first_entry(&space_info->tickets, 876 struct reserve_ticket, list); 877 878 if (ticket->steal && 879 steal_from_global_rsv(fs_info, space_info, ticket)) 880 return true; 881 882 /* 883 * may_commit_transaction will avoid committing the transaction 884 * if it doesn't feel like the space reclaimed by the commit 885 * would result in the ticket succeeding. However if we have a 886 * smaller ticket in the queue it may be small enough to be 887 * satisified by committing the transaction, so if any 888 * subsequent ticket is smaller than the first ticket go ahead 889 * and send us back for another loop through the enospc flushing 890 * code. 891 */ 892 if (first_ticket_bytes == 0) 893 first_ticket_bytes = ticket->bytes; 894 else if (first_ticket_bytes > ticket->bytes) 895 return true; 896 897 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) 898 btrfs_info(fs_info, "failing ticket with %llu bytes", 899 ticket->bytes); 900 901 remove_ticket(space_info, ticket); 902 ticket->error = -ENOSPC; 903 wake_up(&ticket->wait); 904 905 /* 906 * We're just throwing tickets away, so more flushing may not 907 * trip over btrfs_try_granting_tickets, so we need to call it 908 * here to see if we can make progress with the next ticket in 909 * the list. 910 */ 911 btrfs_try_granting_tickets(fs_info, space_info); 912 } 913 return (tickets_id != space_info->tickets_id); 914 } 915 916 /* 917 * This is for normal flushers, we can wait all goddamned day if we want to. We 918 * will loop and continuously try to flush as long as we are making progress. 919 * We count progress as clearing off tickets each time we have to loop. 920 */ 921 static void btrfs_async_reclaim_metadata_space(struct work_struct *work) 922 { 923 struct btrfs_fs_info *fs_info; 924 struct btrfs_space_info *space_info; 925 u64 to_reclaim; 926 int flush_state; 927 int commit_cycles = 0; 928 u64 last_tickets_id; 929 930 fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work); 931 space_info = btrfs_find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA); 932 933 spin_lock(&space_info->lock); 934 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info); 935 if (!to_reclaim) { 936 space_info->flush = 0; 937 spin_unlock(&space_info->lock); 938 return; 939 } 940 last_tickets_id = space_info->tickets_id; 941 spin_unlock(&space_info->lock); 942 943 flush_state = FLUSH_DELAYED_ITEMS_NR; 944 do { 945 flush_space(fs_info, space_info, to_reclaim, flush_state); 946 spin_lock(&space_info->lock); 947 if (list_empty(&space_info->tickets)) { 948 space_info->flush = 0; 949 spin_unlock(&space_info->lock); 950 return; 951 } 952 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, 953 space_info); 954 if (last_tickets_id == space_info->tickets_id) { 955 flush_state++; 956 } else { 957 last_tickets_id = space_info->tickets_id; 958 flush_state = FLUSH_DELAYED_ITEMS_NR; 959 if (commit_cycles) 960 commit_cycles--; 961 } 962 963 /* 964 * We don't want to force a chunk allocation until we've tried 965 * pretty hard to reclaim space. Think of the case where we 966 * freed up a bunch of space and so have a lot of pinned space 967 * to reclaim. We would rather use that than possibly create a 968 * underutilized metadata chunk. So if this is our first run 969 * through the flushing state machine skip ALLOC_CHUNK_FORCE and 970 * commit the transaction. If nothing has changed the next go 971 * around then we can force a chunk allocation. 972 */ 973 if (flush_state == ALLOC_CHUNK_FORCE && !commit_cycles) 974 flush_state++; 975 976 if (flush_state > COMMIT_TRANS) { 977 commit_cycles++; 978 if (commit_cycles > 2) { 979 if (maybe_fail_all_tickets(fs_info, space_info)) { 980 flush_state = FLUSH_DELAYED_ITEMS_NR; 981 commit_cycles--; 982 } else { 983 space_info->flush = 0; 984 } 985 } else { 986 flush_state = FLUSH_DELAYED_ITEMS_NR; 987 } 988 } 989 spin_unlock(&space_info->lock); 990 } while (flush_state <= COMMIT_TRANS); 991 } 992 993 /* 994 * FLUSH_DELALLOC_WAIT: 995 * Space is freed from flushing delalloc in one of two ways. 996 * 997 * 1) compression is on and we allocate less space than we reserved 998 * 2) we are overwriting existing space 999 * 1000 * For #1 that extra space is reclaimed as soon as the delalloc pages are 1001 * COWed, by way of btrfs_add_reserved_bytes() which adds the actual extent 1002 * length to ->bytes_reserved, and subtracts the reserved space from 1003 * ->bytes_may_use. 1004 * 1005 * For #2 this is trickier. Once the ordered extent runs we will drop the 1006 * extent in the range we are overwriting, which creates a delayed ref for 1007 * that freed extent. This however is not reclaimed until the transaction 1008 * commits, thus the next stages. 1009 * 1010 * RUN_DELAYED_IPUTS 1011 * If we are freeing inodes, we want to make sure all delayed iputs have 1012 * completed, because they could have been on an inode with i_nlink == 0, and 1013 * thus have been truncated and freed up space. But again this space is not 1014 * immediately re-usable, it comes in the form of a delayed ref, which must be 1015 * run and then the transaction must be committed. 1016 * 1017 * FLUSH_DELAYED_REFS 1018 * The above two cases generate delayed refs that will affect 1019 * ->total_bytes_pinned. However this counter can be inconsistent with 1020 * reality if there are outstanding delayed refs. This is because we adjust 1021 * the counter based solely on the current set of delayed refs and disregard 1022 * any on-disk state which might include more refs. So for example, if we 1023 * have an extent with 2 references, but we only drop 1, we'll see that there 1024 * is a negative delayed ref count for the extent and assume that the space 1025 * will be freed, and thus increase ->total_bytes_pinned. 1026 * 1027 * Running the delayed refs gives us the actual real view of what will be 1028 * freed at the transaction commit time. This stage will not actually free 1029 * space for us, it just makes sure that may_commit_transaction() has all of 1030 * the information it needs to make the right decision. 1031 * 1032 * COMMIT_TRANS 1033 * This is where we reclaim all of the pinned space generated by the previous 1034 * two stages. We will not commit the transaction if we don't think we're 1035 * likely to satisfy our request, which means if our current free space + 1036 * total_bytes_pinned < reservation we will not commit. This is why the 1037 * previous states are actually important, to make sure we know for sure 1038 * whether committing the transaction will allow us to make progress. 1039 * 1040 * ALLOC_CHUNK_FORCE 1041 * For data we start with alloc chunk force, however we could have been full 1042 * before, and then the transaction commit could have freed new block groups, 1043 * so if we now have space to allocate do the force chunk allocation. 1044 */ 1045 static const enum btrfs_flush_state data_flush_states[] = { 1046 FLUSH_DELALLOC_WAIT, 1047 RUN_DELAYED_IPUTS, 1048 FLUSH_DELAYED_REFS, 1049 COMMIT_TRANS, 1050 ALLOC_CHUNK_FORCE, 1051 }; 1052 1053 static void btrfs_async_reclaim_data_space(struct work_struct *work) 1054 { 1055 struct btrfs_fs_info *fs_info; 1056 struct btrfs_space_info *space_info; 1057 u64 last_tickets_id; 1058 int flush_state = 0; 1059 1060 fs_info = container_of(work, struct btrfs_fs_info, async_data_reclaim_work); 1061 space_info = fs_info->data_sinfo; 1062 1063 spin_lock(&space_info->lock); 1064 if (list_empty(&space_info->tickets)) { 1065 space_info->flush = 0; 1066 spin_unlock(&space_info->lock); 1067 return; 1068 } 1069 last_tickets_id = space_info->tickets_id; 1070 spin_unlock(&space_info->lock); 1071 1072 while (!space_info->full) { 1073 flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE); 1074 spin_lock(&space_info->lock); 1075 if (list_empty(&space_info->tickets)) { 1076 space_info->flush = 0; 1077 spin_unlock(&space_info->lock); 1078 return; 1079 } 1080 last_tickets_id = space_info->tickets_id; 1081 spin_unlock(&space_info->lock); 1082 } 1083 1084 while (flush_state < ARRAY_SIZE(data_flush_states)) { 1085 flush_space(fs_info, space_info, U64_MAX, 1086 data_flush_states[flush_state]); 1087 spin_lock(&space_info->lock); 1088 if (list_empty(&space_info->tickets)) { 1089 space_info->flush = 0; 1090 spin_unlock(&space_info->lock); 1091 return; 1092 } 1093 1094 if (last_tickets_id == space_info->tickets_id) { 1095 flush_state++; 1096 } else { 1097 last_tickets_id = space_info->tickets_id; 1098 flush_state = 0; 1099 } 1100 1101 if (flush_state >= ARRAY_SIZE(data_flush_states)) { 1102 if (space_info->full) { 1103 if (maybe_fail_all_tickets(fs_info, space_info)) 1104 flush_state = 0; 1105 else 1106 space_info->flush = 0; 1107 } else { 1108 flush_state = 0; 1109 } 1110 } 1111 spin_unlock(&space_info->lock); 1112 } 1113 } 1114 1115 void btrfs_init_async_reclaim_work(struct btrfs_fs_info *fs_info) 1116 { 1117 INIT_WORK(&fs_info->async_reclaim_work, btrfs_async_reclaim_metadata_space); 1118 INIT_WORK(&fs_info->async_data_reclaim_work, btrfs_async_reclaim_data_space); 1119 } 1120 1121 static const enum btrfs_flush_state priority_flush_states[] = { 1122 FLUSH_DELAYED_ITEMS_NR, 1123 FLUSH_DELAYED_ITEMS, 1124 ALLOC_CHUNK, 1125 }; 1126 1127 static const enum btrfs_flush_state evict_flush_states[] = { 1128 FLUSH_DELAYED_ITEMS_NR, 1129 FLUSH_DELAYED_ITEMS, 1130 FLUSH_DELAYED_REFS_NR, 1131 FLUSH_DELAYED_REFS, 1132 FLUSH_DELALLOC, 1133 FLUSH_DELALLOC_WAIT, 1134 ALLOC_CHUNK, 1135 COMMIT_TRANS, 1136 }; 1137 1138 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info, 1139 struct btrfs_space_info *space_info, 1140 struct reserve_ticket *ticket, 1141 const enum btrfs_flush_state *states, 1142 int states_nr) 1143 { 1144 u64 to_reclaim; 1145 int flush_state; 1146 1147 spin_lock(&space_info->lock); 1148 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info); 1149 if (!to_reclaim) { 1150 spin_unlock(&space_info->lock); 1151 return; 1152 } 1153 spin_unlock(&space_info->lock); 1154 1155 flush_state = 0; 1156 do { 1157 flush_space(fs_info, space_info, to_reclaim, states[flush_state]); 1158 flush_state++; 1159 spin_lock(&space_info->lock); 1160 if (ticket->bytes == 0) { 1161 spin_unlock(&space_info->lock); 1162 return; 1163 } 1164 spin_unlock(&space_info->lock); 1165 } while (flush_state < states_nr); 1166 } 1167 1168 static void priority_reclaim_data_space(struct btrfs_fs_info *fs_info, 1169 struct btrfs_space_info *space_info, 1170 struct reserve_ticket *ticket) 1171 { 1172 while (!space_info->full) { 1173 flush_space(fs_info, space_info, U64_MAX, ALLOC_CHUNK_FORCE); 1174 spin_lock(&space_info->lock); 1175 if (ticket->bytes == 0) { 1176 spin_unlock(&space_info->lock); 1177 return; 1178 } 1179 spin_unlock(&space_info->lock); 1180 } 1181 } 1182 1183 static void wait_reserve_ticket(struct btrfs_fs_info *fs_info, 1184 struct btrfs_space_info *space_info, 1185 struct reserve_ticket *ticket) 1186 1187 { 1188 DEFINE_WAIT(wait); 1189 int ret = 0; 1190 1191 spin_lock(&space_info->lock); 1192 while (ticket->bytes > 0 && ticket->error == 0) { 1193 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE); 1194 if (ret) { 1195 /* 1196 * Delete us from the list. After we unlock the space 1197 * info, we don't want the async reclaim job to reserve 1198 * space for this ticket. If that would happen, then the 1199 * ticket's task would not known that space was reserved 1200 * despite getting an error, resulting in a space leak 1201 * (bytes_may_use counter of our space_info). 1202 */ 1203 remove_ticket(space_info, ticket); 1204 ticket->error = -EINTR; 1205 break; 1206 } 1207 spin_unlock(&space_info->lock); 1208 1209 schedule(); 1210 1211 finish_wait(&ticket->wait, &wait); 1212 spin_lock(&space_info->lock); 1213 } 1214 spin_unlock(&space_info->lock); 1215 } 1216 1217 /** 1218 * Do the appropriate flushing and waiting for a ticket 1219 * 1220 * @fs_info: the filesystem 1221 * @space_info: space info for the reservation 1222 * @ticket: ticket for the reservation 1223 * @flush: how much we can flush 1224 * 1225 * This does the work of figuring out how to flush for the ticket, waiting for 1226 * the reservation, and returning the appropriate error if there is one. 1227 */ 1228 static int handle_reserve_ticket(struct btrfs_fs_info *fs_info, 1229 struct btrfs_space_info *space_info, 1230 struct reserve_ticket *ticket, 1231 enum btrfs_reserve_flush_enum flush) 1232 { 1233 int ret; 1234 1235 switch (flush) { 1236 case BTRFS_RESERVE_FLUSH_DATA: 1237 case BTRFS_RESERVE_FLUSH_ALL: 1238 case BTRFS_RESERVE_FLUSH_ALL_STEAL: 1239 wait_reserve_ticket(fs_info, space_info, ticket); 1240 break; 1241 case BTRFS_RESERVE_FLUSH_LIMIT: 1242 priority_reclaim_metadata_space(fs_info, space_info, ticket, 1243 priority_flush_states, 1244 ARRAY_SIZE(priority_flush_states)); 1245 break; 1246 case BTRFS_RESERVE_FLUSH_EVICT: 1247 priority_reclaim_metadata_space(fs_info, space_info, ticket, 1248 evict_flush_states, 1249 ARRAY_SIZE(evict_flush_states)); 1250 break; 1251 case BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE: 1252 priority_reclaim_data_space(fs_info, space_info, ticket); 1253 break; 1254 default: 1255 ASSERT(0); 1256 break; 1257 } 1258 1259 spin_lock(&space_info->lock); 1260 ret = ticket->error; 1261 if (ticket->bytes || ticket->error) { 1262 /* 1263 * We were a priority ticket, so we need to delete ourselves 1264 * from the list. Because we could have other priority tickets 1265 * behind us that require less space, run 1266 * btrfs_try_granting_tickets() to see if their reservations can 1267 * now be made. 1268 */ 1269 if (!list_empty(&ticket->list)) { 1270 remove_ticket(space_info, ticket); 1271 btrfs_try_granting_tickets(fs_info, space_info); 1272 } 1273 1274 if (!ret) 1275 ret = -ENOSPC; 1276 } 1277 spin_unlock(&space_info->lock); 1278 ASSERT(list_empty(&ticket->list)); 1279 /* 1280 * Check that we can't have an error set if the reservation succeeded, 1281 * as that would confuse tasks and lead them to error out without 1282 * releasing reserved space (if an error happens the expectation is that 1283 * space wasn't reserved at all). 1284 */ 1285 ASSERT(!(ticket->bytes == 0 && ticket->error)); 1286 return ret; 1287 } 1288 1289 /* 1290 * This returns true if this flush state will go through the ordinary flushing 1291 * code. 1292 */ 1293 static inline bool is_normal_flushing(enum btrfs_reserve_flush_enum flush) 1294 { 1295 return (flush == BTRFS_RESERVE_FLUSH_ALL) || 1296 (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL); 1297 } 1298 1299 /** 1300 * Try to reserve bytes from the block_rsv's space 1301 * 1302 * @fs_info: the filesystem 1303 * @space_info: space info we want to allocate from 1304 * @orig_bytes: number of bytes we want 1305 * @flush: whether or not we can flush to make our reservation 1306 * 1307 * This will reserve orig_bytes number of bytes from the space info associated 1308 * with the block_rsv. If there is not enough space it will make an attempt to 1309 * flush out space to make room. It will do this by flushing delalloc if 1310 * possible or committing the transaction. If flush is 0 then no attempts to 1311 * regain reservations will be made and this will fail if there is not enough 1312 * space already. 1313 */ 1314 static int __reserve_bytes(struct btrfs_fs_info *fs_info, 1315 struct btrfs_space_info *space_info, u64 orig_bytes, 1316 enum btrfs_reserve_flush_enum flush) 1317 { 1318 struct work_struct *async_work; 1319 struct reserve_ticket ticket; 1320 u64 used; 1321 int ret = 0; 1322 bool pending_tickets; 1323 1324 ASSERT(orig_bytes); 1325 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL); 1326 1327 if (flush == BTRFS_RESERVE_FLUSH_DATA) 1328 async_work = &fs_info->async_data_reclaim_work; 1329 else 1330 async_work = &fs_info->async_reclaim_work; 1331 1332 spin_lock(&space_info->lock); 1333 ret = -ENOSPC; 1334 used = btrfs_space_info_used(space_info, true); 1335 1336 /* 1337 * We don't want NO_FLUSH allocations to jump everybody, they can 1338 * generally handle ENOSPC in a different way, so treat them the same as 1339 * normal flushers when it comes to skipping pending tickets. 1340 */ 1341 if (is_normal_flushing(flush) || (flush == BTRFS_RESERVE_NO_FLUSH)) 1342 pending_tickets = !list_empty(&space_info->tickets) || 1343 !list_empty(&space_info->priority_tickets); 1344 else 1345 pending_tickets = !list_empty(&space_info->priority_tickets); 1346 1347 /* 1348 * Carry on if we have enough space (short-circuit) OR call 1349 * can_overcommit() to ensure we can overcommit to continue. 1350 */ 1351 if (!pending_tickets && 1352 ((used + orig_bytes <= space_info->total_bytes) || 1353 btrfs_can_overcommit(fs_info, space_info, orig_bytes, flush))) { 1354 btrfs_space_info_update_bytes_may_use(fs_info, space_info, 1355 orig_bytes); 1356 ret = 0; 1357 } 1358 1359 /* 1360 * If we couldn't make a reservation then setup our reservation ticket 1361 * and kick the async worker if it's not already running. 1362 * 1363 * If we are a priority flusher then we just need to add our ticket to 1364 * the list and we will do our own flushing further down. 1365 */ 1366 if (ret && flush != BTRFS_RESERVE_NO_FLUSH) { 1367 ticket.bytes = orig_bytes; 1368 ticket.error = 0; 1369 space_info->reclaim_size += ticket.bytes; 1370 init_waitqueue_head(&ticket.wait); 1371 ticket.steal = (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL); 1372 if (flush == BTRFS_RESERVE_FLUSH_ALL || 1373 flush == BTRFS_RESERVE_FLUSH_ALL_STEAL || 1374 flush == BTRFS_RESERVE_FLUSH_DATA) { 1375 list_add_tail(&ticket.list, &space_info->tickets); 1376 if (!space_info->flush) { 1377 space_info->flush = 1; 1378 trace_btrfs_trigger_flush(fs_info, 1379 space_info->flags, 1380 orig_bytes, flush, 1381 "enospc"); 1382 queue_work(system_unbound_wq, async_work); 1383 } 1384 } else { 1385 list_add_tail(&ticket.list, 1386 &space_info->priority_tickets); 1387 } 1388 } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) { 1389 used += orig_bytes; 1390 /* 1391 * We will do the space reservation dance during log replay, 1392 * which means we won't have fs_info->fs_root set, so don't do 1393 * the async reclaim as we will panic. 1394 */ 1395 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) && 1396 need_do_async_reclaim(fs_info, space_info, used) && 1397 !work_busy(&fs_info->async_reclaim_work)) { 1398 trace_btrfs_trigger_flush(fs_info, space_info->flags, 1399 orig_bytes, flush, "preempt"); 1400 queue_work(system_unbound_wq, 1401 &fs_info->async_reclaim_work); 1402 } 1403 } 1404 spin_unlock(&space_info->lock); 1405 if (!ret || flush == BTRFS_RESERVE_NO_FLUSH) 1406 return ret; 1407 1408 return handle_reserve_ticket(fs_info, space_info, &ticket, flush); 1409 } 1410 1411 /** 1412 * Trye to reserve metadata bytes from the block_rsv's space 1413 * 1414 * @root: the root we're allocating for 1415 * @block_rsv: block_rsv we're allocating for 1416 * @orig_bytes: number of bytes we want 1417 * @flush: whether or not we can flush to make our reservation 1418 * 1419 * This will reserve orig_bytes number of bytes from the space info associated 1420 * with the block_rsv. If there is not enough space it will make an attempt to 1421 * flush out space to make room. It will do this by flushing delalloc if 1422 * possible or committing the transaction. If flush is 0 then no attempts to 1423 * regain reservations will be made and this will fail if there is not enough 1424 * space already. 1425 */ 1426 int btrfs_reserve_metadata_bytes(struct btrfs_root *root, 1427 struct btrfs_block_rsv *block_rsv, 1428 u64 orig_bytes, 1429 enum btrfs_reserve_flush_enum flush) 1430 { 1431 struct btrfs_fs_info *fs_info = root->fs_info; 1432 struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv; 1433 int ret; 1434 1435 ret = __reserve_bytes(fs_info, block_rsv->space_info, orig_bytes, flush); 1436 if (ret == -ENOSPC && 1437 unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) { 1438 if (block_rsv != global_rsv && 1439 !btrfs_block_rsv_use_bytes(global_rsv, orig_bytes)) 1440 ret = 0; 1441 } 1442 if (ret == -ENOSPC) { 1443 trace_btrfs_space_reservation(fs_info, "space_info:enospc", 1444 block_rsv->space_info->flags, 1445 orig_bytes, 1); 1446 1447 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) 1448 btrfs_dump_space_info(fs_info, block_rsv->space_info, 1449 orig_bytes, 0); 1450 } 1451 return ret; 1452 } 1453 1454 /** 1455 * Try to reserve data bytes for an allocation 1456 * 1457 * @fs_info: the filesystem 1458 * @bytes: number of bytes we need 1459 * @flush: how we are allowed to flush 1460 * 1461 * This will reserve bytes from the data space info. If there is not enough 1462 * space then we will attempt to flush space as specified by flush. 1463 */ 1464 int btrfs_reserve_data_bytes(struct btrfs_fs_info *fs_info, u64 bytes, 1465 enum btrfs_reserve_flush_enum flush) 1466 { 1467 struct btrfs_space_info *data_sinfo = fs_info->data_sinfo; 1468 int ret; 1469 1470 ASSERT(flush == BTRFS_RESERVE_FLUSH_DATA || 1471 flush == BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE); 1472 ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_DATA); 1473 1474 ret = __reserve_bytes(fs_info, data_sinfo, bytes, flush); 1475 if (ret == -ENOSPC) { 1476 trace_btrfs_space_reservation(fs_info, "space_info:enospc", 1477 data_sinfo->flags, bytes, 1); 1478 if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) 1479 btrfs_dump_space_info(fs_info, data_sinfo, bytes, 0); 1480 } 1481 return ret; 1482 } 1483