1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Copyright (C) 2007 Oracle. All rights reserved. 4 */ 5 6#include <linux/kthread.h> 7#include <linux/pagemap.h> 8 9#include "ctree.h" 10#include "disk-io.h" 11#include "free-space-cache.h" 12#include "inode-map.h" 13#include "transaction.h" 14#include "delalloc-space.h" 15 16static void fail_caching_thread(struct btrfs_root *root) 17{ 18 struct btrfs_fs_info *fs_info = root->fs_info; 19 20 btrfs_warn(fs_info, "failed to start inode caching task"); 21 btrfs_clear_pending_and_info(fs_info, INODE_MAP_CACHE, 22 "disabling inode map caching"); 23 spin_lock(&root->ino_cache_lock); 24 root->ino_cache_state = BTRFS_CACHE_ERROR; 25 spin_unlock(&root->ino_cache_lock); 26 wake_up(&root->ino_cache_wait); 27} 28 29static int caching_kthread(void *data) 30{ 31 struct btrfs_root *root = data; 32 struct btrfs_fs_info *fs_info = root->fs_info; 33 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; 34 struct btrfs_key key; 35 struct btrfs_path *path; 36 struct extent_buffer *leaf; 37 u64 last = (u64)-1; 38 int slot; 39 int ret; 40 41 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE)) 42 return 0; 43 44 path = btrfs_alloc_path(); 45 if (!path) { 46 fail_caching_thread(root); 47 return -ENOMEM; 48 } 49 50 /* Since the commit root is read-only, we can safely skip locking. */ 51 path->skip_locking = 1; 52 path->search_commit_root = 1; 53 path->reada = READA_FORWARD; 54 55 key.objectid = BTRFS_FIRST_FREE_OBJECTID; 56 key.offset = 0; 57 key.type = BTRFS_INODE_ITEM_KEY; 58again: 59 /* need to make sure the commit_root doesn't disappear */ 60 down_read(&fs_info->commit_root_sem); 61 62 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 63 if (ret < 0) 64 goto out; 65 66 while (1) { 67 if (btrfs_fs_closing(fs_info)) 68 goto out; 69 70 leaf = path->nodes[0]; 71 slot = path->slots[0]; 72 if (slot >= btrfs_header_nritems(leaf)) { 73 ret = btrfs_next_leaf(root, path); 74 if (ret < 0) 75 goto out; 76 else if (ret > 0) 77 break; 78 79 if (need_resched() || 80 btrfs_transaction_in_commit(fs_info)) { 81 leaf = path->nodes[0]; 82 83 if (WARN_ON(btrfs_header_nritems(leaf) == 0)) 84 break; 85 86 /* 87 * Save the key so we can advances forward 88 * in the next search. 89 */ 90 btrfs_item_key_to_cpu(leaf, &key, 0); 91 btrfs_release_path(path); 92 root->ino_cache_progress = last; 93 up_read(&fs_info->commit_root_sem); 94 schedule_timeout(1); 95 goto again; 96 } else 97 continue; 98 } 99 100 btrfs_item_key_to_cpu(leaf, &key, slot); 101 102 if (key.type != BTRFS_INODE_ITEM_KEY) 103 goto next; 104 105 if (key.objectid >= root->highest_objectid) 106 break; 107 108 if (last != (u64)-1 && last + 1 != key.objectid) { 109 __btrfs_add_free_space(fs_info, ctl, last + 1, 110 key.objectid - last - 1, 0); 111 wake_up(&root->ino_cache_wait); 112 } 113 114 last = key.objectid; 115next: 116 path->slots[0]++; 117 } 118 119 if (last < root->highest_objectid - 1) { 120 __btrfs_add_free_space(fs_info, ctl, last + 1, 121 root->highest_objectid - last - 1, 0); 122 } 123 124 spin_lock(&root->ino_cache_lock); 125 root->ino_cache_state = BTRFS_CACHE_FINISHED; 126 spin_unlock(&root->ino_cache_lock); 127 128 root->ino_cache_progress = (u64)-1; 129 btrfs_unpin_free_ino(root); 130out: 131 wake_up(&root->ino_cache_wait); 132 up_read(&fs_info->commit_root_sem); 133 134 btrfs_free_path(path); 135 136 return ret; 137} 138 139static void start_caching(struct btrfs_root *root) 140{ 141 struct btrfs_fs_info *fs_info = root->fs_info; 142 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; 143 struct task_struct *tsk; 144 int ret; 145 u64 objectid; 146 147 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE)) 148 return; 149 150 spin_lock(&root->ino_cache_lock); 151 if (root->ino_cache_state != BTRFS_CACHE_NO) { 152 spin_unlock(&root->ino_cache_lock); 153 return; 154 } 155 156 root->ino_cache_state = BTRFS_CACHE_STARTED; 157 spin_unlock(&root->ino_cache_lock); 158 159 ret = load_free_ino_cache(fs_info, root); 160 if (ret == 1) { 161 spin_lock(&root->ino_cache_lock); 162 root->ino_cache_state = BTRFS_CACHE_FINISHED; 163 spin_unlock(&root->ino_cache_lock); 164 wake_up(&root->ino_cache_wait); 165 return; 166 } 167 168 /* 169 * It can be quite time-consuming to fill the cache by searching 170 * through the extent tree, and this can keep ino allocation path 171 * waiting. Therefore at start we quickly find out the highest 172 * inode number and we know we can use inode numbers which fall in 173 * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID]. 174 */ 175 ret = btrfs_find_free_objectid(root, &objectid); 176 if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) { 177 __btrfs_add_free_space(fs_info, ctl, objectid, 178 BTRFS_LAST_FREE_OBJECTID - objectid + 1, 179 0); 180 wake_up(&root->ino_cache_wait); 181 } 182 183 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu", 184 root->root_key.objectid); 185 if (IS_ERR(tsk)) 186 fail_caching_thread(root); 187} 188 189int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid) 190{ 191 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE)) 192 return btrfs_find_free_objectid(root, objectid); 193 194again: 195 *objectid = btrfs_find_ino_for_alloc(root); 196 197 if (*objectid != 0) 198 return 0; 199 200 start_caching(root); 201 202 wait_event(root->ino_cache_wait, 203 root->ino_cache_state == BTRFS_CACHE_FINISHED || 204 root->ino_cache_state == BTRFS_CACHE_ERROR || 205 root->free_ino_ctl->free_space > 0); 206 207 if (root->ino_cache_state == BTRFS_CACHE_FINISHED && 208 root->free_ino_ctl->free_space == 0) 209 return -ENOSPC; 210 else if (root->ino_cache_state == BTRFS_CACHE_ERROR) 211 return btrfs_find_free_objectid(root, objectid); 212 else 213 goto again; 214} 215 216void btrfs_return_ino(struct btrfs_root *root, u64 objectid) 217{ 218 struct btrfs_fs_info *fs_info = root->fs_info; 219 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned; 220 221 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE)) 222 return; 223again: 224 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) { 225 __btrfs_add_free_space(fs_info, pinned, objectid, 1, 0); 226 } else { 227 down_write(&fs_info->commit_root_sem); 228 spin_lock(&root->ino_cache_lock); 229 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) { 230 spin_unlock(&root->ino_cache_lock); 231 up_write(&fs_info->commit_root_sem); 232 goto again; 233 } 234 spin_unlock(&root->ino_cache_lock); 235 236 start_caching(root); 237 238 __btrfs_add_free_space(fs_info, pinned, objectid, 1, 0); 239 240 up_write(&fs_info->commit_root_sem); 241 } 242} 243 244/* 245 * When a transaction is committed, we'll move those inode numbers which are 246 * smaller than root->ino_cache_progress from pinned tree to free_ino tree, and 247 * others will just be dropped, because the commit root we were searching has 248 * changed. 249 * 250 * Must be called with root->fs_info->commit_root_sem held 251 */ 252void btrfs_unpin_free_ino(struct btrfs_root *root) 253{ 254 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; 255 struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset; 256 spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock; 257 struct btrfs_free_space *info; 258 struct rb_node *n; 259 u64 count; 260 261 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE)) 262 return; 263 264 while (1) { 265 spin_lock(rbroot_lock); 266 n = rb_first(rbroot); 267 if (!n) { 268 spin_unlock(rbroot_lock); 269 break; 270 } 271 272 info = rb_entry(n, struct btrfs_free_space, offset_index); 273 BUG_ON(info->bitmap); /* Logic error */ 274 275 if (info->offset > root->ino_cache_progress) 276 count = 0; 277 else 278 count = min(root->ino_cache_progress - info->offset + 1, 279 info->bytes); 280 281 rb_erase(&info->offset_index, rbroot); 282 spin_unlock(rbroot_lock); 283 if (count) 284 __btrfs_add_free_space(root->fs_info, ctl, 285 info->offset, count, 0); 286 kmem_cache_free(btrfs_free_space_cachep, info); 287 } 288} 289 290#define INIT_THRESHOLD ((SZ_32K / 2) / sizeof(struct btrfs_free_space)) 291#define INODES_PER_BITMAP (PAGE_SIZE * 8) 292 293/* 294 * The goal is to keep the memory used by the free_ino tree won't 295 * exceed the memory if we use bitmaps only. 296 */ 297static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl) 298{ 299 struct btrfs_free_space *info; 300 struct rb_node *n; 301 int max_ino; 302 int max_bitmaps; 303 304 n = rb_last(&ctl->free_space_offset); 305 if (!n) { 306 ctl->extents_thresh = INIT_THRESHOLD; 307 return; 308 } 309 info = rb_entry(n, struct btrfs_free_space, offset_index); 310 311 /* 312 * Find the maximum inode number in the filesystem. Note we 313 * ignore the fact that this can be a bitmap, because we are 314 * not doing precise calculation. 315 */ 316 max_ino = info->bytes - 1; 317 318 max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP; 319 if (max_bitmaps <= ctl->total_bitmaps) { 320 ctl->extents_thresh = 0; 321 return; 322 } 323 324 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) * 325 PAGE_SIZE / sizeof(*info); 326} 327 328/* 329 * We don't fall back to bitmap, if we are below the extents threshold 330 * or this chunk of inode numbers is a big one. 331 */ 332static bool use_bitmap(struct btrfs_free_space_ctl *ctl, 333 struct btrfs_free_space *info) 334{ 335 if (ctl->free_extents < ctl->extents_thresh || 336 info->bytes > INODES_PER_BITMAP / 10) 337 return false; 338 339 return true; 340} 341 342static const struct btrfs_free_space_op free_ino_op = { 343 .recalc_thresholds = recalculate_thresholds, 344 .use_bitmap = use_bitmap, 345}; 346 347static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl) 348{ 349} 350 351static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl, 352 struct btrfs_free_space *info) 353{ 354 /* 355 * We always use extents for two reasons: 356 * 357 * - The pinned tree is only used during the process of caching 358 * work. 359 * - Make code simpler. See btrfs_unpin_free_ino(). 360 */ 361 return false; 362} 363 364static const struct btrfs_free_space_op pinned_free_ino_op = { 365 .recalc_thresholds = pinned_recalc_thresholds, 366 .use_bitmap = pinned_use_bitmap, 367}; 368 369void btrfs_init_free_ino_ctl(struct btrfs_root *root) 370{ 371 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; 372 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned; 373 374 spin_lock_init(&ctl->tree_lock); 375 ctl->unit = 1; 376 ctl->start = 0; 377 ctl->private = NULL; 378 ctl->op = &free_ino_op; 379 INIT_LIST_HEAD(&ctl->trimming_ranges); 380 mutex_init(&ctl->cache_writeout_mutex); 381 382 /* 383 * Initially we allow to use 16K of ram to cache chunks of 384 * inode numbers before we resort to bitmaps. This is somewhat 385 * arbitrary, but it will be adjusted in runtime. 386 */ 387 ctl->extents_thresh = INIT_THRESHOLD; 388 389 spin_lock_init(&pinned->tree_lock); 390 pinned->unit = 1; 391 pinned->start = 0; 392 pinned->private = NULL; 393 pinned->extents_thresh = 0; 394 pinned->op = &pinned_free_ino_op; 395} 396 397int btrfs_save_ino_cache(struct btrfs_root *root, 398 struct btrfs_trans_handle *trans) 399{ 400 struct btrfs_fs_info *fs_info = root->fs_info; 401 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl; 402 struct btrfs_path *path; 403 struct inode *inode; 404 struct btrfs_block_rsv *rsv; 405 struct extent_changeset *data_reserved = NULL; 406 u64 num_bytes; 407 u64 alloc_hint = 0; 408 int ret; 409 int prealloc; 410 bool retry = false; 411 412 /* only fs tree and subvol/snap needs ino cache */ 413 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID && 414 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID || 415 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID)) 416 return 0; 417 418 /* Don't save inode cache if we are deleting this root */ 419 if (btrfs_root_refs(&root->root_item) == 0) 420 return 0; 421 422 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE)) 423 return 0; 424 425 path = btrfs_alloc_path(); 426 if (!path) 427 return -ENOMEM; 428 429 rsv = trans->block_rsv; 430 trans->block_rsv = &fs_info->trans_block_rsv; 431 432 num_bytes = trans->bytes_reserved; 433 /* 434 * 1 item for inode item insertion if need 435 * 4 items for inode item update (in the worst case) 436 * 1 items for slack space if we need do truncation 437 * 1 item for free space object 438 * 3 items for pre-allocation 439 */ 440 trans->bytes_reserved = btrfs_calc_insert_metadata_size(fs_info, 10); 441 ret = btrfs_block_rsv_add(root, trans->block_rsv, 442 trans->bytes_reserved, 443 BTRFS_RESERVE_NO_FLUSH); 444 if (ret) 445 goto out; 446 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid, 447 trans->bytes_reserved, 1); 448again: 449 inode = lookup_free_ino_inode(root, path); 450 if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) { 451 ret = PTR_ERR(inode); 452 goto out_release; 453 } 454 455 if (IS_ERR(inode)) { 456 BUG_ON(retry); /* Logic error */ 457 retry = true; 458 459 ret = create_free_ino_inode(root, trans, path); 460 if (ret) 461 goto out_release; 462 goto again; 463 } 464 465 BTRFS_I(inode)->generation = 0; 466 ret = btrfs_update_inode(trans, root, inode); 467 if (ret) { 468 btrfs_abort_transaction(trans, ret); 469 goto out_put; 470 } 471 472 if (i_size_read(inode) > 0) { 473 ret = btrfs_truncate_free_space_cache(trans, NULL, inode); 474 if (ret) { 475 if (ret != -ENOSPC) 476 btrfs_abort_transaction(trans, ret); 477 goto out_put; 478 } 479 } 480 481 spin_lock(&root->ino_cache_lock); 482 if (root->ino_cache_state != BTRFS_CACHE_FINISHED) { 483 ret = -1; 484 spin_unlock(&root->ino_cache_lock); 485 goto out_put; 486 } 487 spin_unlock(&root->ino_cache_lock); 488 489 spin_lock(&ctl->tree_lock); 490 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents; 491 prealloc = ALIGN(prealloc, PAGE_SIZE); 492 prealloc += ctl->total_bitmaps * PAGE_SIZE; 493 spin_unlock(&ctl->tree_lock); 494 495 /* Just to make sure we have enough space */ 496 prealloc += 8 * PAGE_SIZE; 497 498 ret = btrfs_delalloc_reserve_space(BTRFS_I(inode), &data_reserved, 0, 499 prealloc); 500 if (ret) 501 goto out_put; 502 503 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc, 504 prealloc, prealloc, &alloc_hint); 505 if (ret) { 506 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc); 507 btrfs_delalloc_release_metadata(BTRFS_I(inode), prealloc, true); 508 goto out_put; 509 } 510 511 ret = btrfs_write_out_ino_cache(root, trans, path, inode); 512 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc); 513out_put: 514 iput(inode); 515out_release: 516 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid, 517 trans->bytes_reserved, 0); 518 btrfs_block_rsv_release(fs_info, trans->block_rsv, 519 trans->bytes_reserved, NULL); 520out: 521 trans->block_rsv = rsv; 522 trans->bytes_reserved = num_bytes; 523 524 btrfs_free_path(path); 525 extent_changeset_free(data_reserved); 526 return ret; 527} 528