1 /* 2 * fs/f2fs/gc.c 3 * 4 * Copyright (c) 2012 Samsung Electronics Co., Ltd. 5 * http://www.samsung.com/ 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 */ 11 #include <linux/fs.h> 12 #include <linux/module.h> 13 #include <linux/backing-dev.h> 14 #include <linux/init.h> 15 #include <linux/f2fs_fs.h> 16 #include <linux/kthread.h> 17 #include <linux/delay.h> 18 #include <linux/freezer.h> 19 20 #include "f2fs.h" 21 #include "node.h" 22 #include "segment.h" 23 #include "gc.h" 24 #include <trace/events/f2fs.h> 25 26 static int gc_thread_func(void *data) 27 { 28 struct f2fs_sb_info *sbi = data; 29 struct f2fs_gc_kthread *gc_th = sbi->gc_thread; 30 wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head; 31 long wait_ms; 32 33 wait_ms = gc_th->min_sleep_time; 34 35 do { 36 if (try_to_freeze()) 37 continue; 38 else 39 wait_event_interruptible_timeout(*wq, 40 kthread_should_stop(), 41 msecs_to_jiffies(wait_ms)); 42 if (kthread_should_stop()) 43 break; 44 45 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) { 46 increase_sleep_time(gc_th, &wait_ms); 47 continue; 48 } 49 50 #ifdef CONFIG_F2FS_FAULT_INJECTION 51 if (time_to_inject(sbi, FAULT_CHECKPOINT)) 52 f2fs_stop_checkpoint(sbi, false); 53 #endif 54 55 /* 56 * [GC triggering condition] 57 * 0. GC is not conducted currently. 58 * 1. There are enough dirty segments. 59 * 2. IO subsystem is idle by checking the # of writeback pages. 60 * 3. IO subsystem is idle by checking the # of requests in 61 * bdev's request list. 62 * 63 * Note) We have to avoid triggering GCs frequently. 64 * Because it is possible that some segments can be 65 * invalidated soon after by user update or deletion. 66 * So, I'd like to wait some time to collect dirty segments. 67 */ 68 if (!mutex_trylock(&sbi->gc_mutex)) 69 continue; 70 71 if (!is_idle(sbi)) { 72 increase_sleep_time(gc_th, &wait_ms); 73 mutex_unlock(&sbi->gc_mutex); 74 continue; 75 } 76 77 if (has_enough_invalid_blocks(sbi)) 78 decrease_sleep_time(gc_th, &wait_ms); 79 else 80 increase_sleep_time(gc_th, &wait_ms); 81 82 stat_inc_bggc_count(sbi); 83 84 /* if return value is not zero, no victim was selected */ 85 if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC), true)) 86 wait_ms = gc_th->no_gc_sleep_time; 87 88 trace_f2fs_background_gc(sbi->sb, wait_ms, 89 prefree_segments(sbi), free_segments(sbi)); 90 91 /* balancing f2fs's metadata periodically */ 92 f2fs_balance_fs_bg(sbi); 93 94 } while (!kthread_should_stop()); 95 return 0; 96 } 97 98 int start_gc_thread(struct f2fs_sb_info *sbi) 99 { 100 struct f2fs_gc_kthread *gc_th; 101 dev_t dev = sbi->sb->s_bdev->bd_dev; 102 int err = 0; 103 104 gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL); 105 if (!gc_th) { 106 err = -ENOMEM; 107 goto out; 108 } 109 110 gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME; 111 gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME; 112 gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME; 113 114 gc_th->gc_idle = 0; 115 116 sbi->gc_thread = gc_th; 117 init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head); 118 sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi, 119 "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev)); 120 if (IS_ERR(gc_th->f2fs_gc_task)) { 121 err = PTR_ERR(gc_th->f2fs_gc_task); 122 kfree(gc_th); 123 sbi->gc_thread = NULL; 124 } 125 out: 126 return err; 127 } 128 129 void stop_gc_thread(struct f2fs_sb_info *sbi) 130 { 131 struct f2fs_gc_kthread *gc_th = sbi->gc_thread; 132 if (!gc_th) 133 return; 134 kthread_stop(gc_th->f2fs_gc_task); 135 kfree(gc_th); 136 sbi->gc_thread = NULL; 137 } 138 139 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type) 140 { 141 int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY; 142 143 if (gc_th && gc_th->gc_idle) { 144 if (gc_th->gc_idle == 1) 145 gc_mode = GC_CB; 146 else if (gc_th->gc_idle == 2) 147 gc_mode = GC_GREEDY; 148 } 149 return gc_mode; 150 } 151 152 static void select_policy(struct f2fs_sb_info *sbi, int gc_type, 153 int type, struct victim_sel_policy *p) 154 { 155 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); 156 157 if (p->alloc_mode == SSR) { 158 p->gc_mode = GC_GREEDY; 159 p->dirty_segmap = dirty_i->dirty_segmap[type]; 160 p->max_search = dirty_i->nr_dirty[type]; 161 p->ofs_unit = 1; 162 } else { 163 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type); 164 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY]; 165 p->max_search = dirty_i->nr_dirty[DIRTY]; 166 p->ofs_unit = sbi->segs_per_sec; 167 } 168 169 if (p->max_search > sbi->max_victim_search) 170 p->max_search = sbi->max_victim_search; 171 172 p->offset = sbi->last_victim[p->gc_mode]; 173 } 174 175 static unsigned int get_max_cost(struct f2fs_sb_info *sbi, 176 struct victim_sel_policy *p) 177 { 178 /* SSR allocates in a segment unit */ 179 if (p->alloc_mode == SSR) 180 return sbi->blocks_per_seg; 181 if (p->gc_mode == GC_GREEDY) 182 return sbi->blocks_per_seg * p->ofs_unit; 183 else if (p->gc_mode == GC_CB) 184 return UINT_MAX; 185 else /* No other gc_mode */ 186 return 0; 187 } 188 189 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi) 190 { 191 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); 192 unsigned int secno; 193 194 /* 195 * If the gc_type is FG_GC, we can select victim segments 196 * selected by background GC before. 197 * Those segments guarantee they have small valid blocks. 198 */ 199 for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) { 200 if (sec_usage_check(sbi, secno)) 201 continue; 202 clear_bit(secno, dirty_i->victim_secmap); 203 return secno * sbi->segs_per_sec; 204 } 205 return NULL_SEGNO; 206 } 207 208 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno) 209 { 210 struct sit_info *sit_i = SIT_I(sbi); 211 unsigned int secno = GET_SECNO(sbi, segno); 212 unsigned int start = secno * sbi->segs_per_sec; 213 unsigned long long mtime = 0; 214 unsigned int vblocks; 215 unsigned char age = 0; 216 unsigned char u; 217 unsigned int i; 218 219 for (i = 0; i < sbi->segs_per_sec; i++) 220 mtime += get_seg_entry(sbi, start + i)->mtime; 221 vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec); 222 223 mtime = div_u64(mtime, sbi->segs_per_sec); 224 vblocks = div_u64(vblocks, sbi->segs_per_sec); 225 226 u = (vblocks * 100) >> sbi->log_blocks_per_seg; 227 228 /* Handle if the system time has changed by the user */ 229 if (mtime < sit_i->min_mtime) 230 sit_i->min_mtime = mtime; 231 if (mtime > sit_i->max_mtime) 232 sit_i->max_mtime = mtime; 233 if (sit_i->max_mtime != sit_i->min_mtime) 234 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime), 235 sit_i->max_mtime - sit_i->min_mtime); 236 237 return UINT_MAX - ((100 * (100 - u) * age) / (100 + u)); 238 } 239 240 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi, 241 unsigned int segno, struct victim_sel_policy *p) 242 { 243 if (p->alloc_mode == SSR) 244 return get_seg_entry(sbi, segno)->ckpt_valid_blocks; 245 246 /* alloc_mode == LFS */ 247 if (p->gc_mode == GC_GREEDY) 248 return get_valid_blocks(sbi, segno, sbi->segs_per_sec); 249 else 250 return get_cb_cost(sbi, segno); 251 } 252 253 static unsigned int count_bits(const unsigned long *addr, 254 unsigned int offset, unsigned int len) 255 { 256 unsigned int end = offset + len, sum = 0; 257 258 while (offset < end) { 259 if (test_bit(offset++, addr)) 260 ++sum; 261 } 262 return sum; 263 } 264 265 /* 266 * This function is called from two paths. 267 * One is garbage collection and the other is SSR segment selection. 268 * When it is called during GC, it just gets a victim segment 269 * and it does not remove it from dirty seglist. 270 * When it is called from SSR segment selection, it finds a segment 271 * which has minimum valid blocks and removes it from dirty seglist. 272 */ 273 static int get_victim_by_default(struct f2fs_sb_info *sbi, 274 unsigned int *result, int gc_type, int type, char alloc_mode) 275 { 276 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi); 277 struct victim_sel_policy p; 278 unsigned int secno, last_victim; 279 unsigned int last_segment = MAIN_SEGS(sbi); 280 unsigned int nsearched = 0; 281 282 mutex_lock(&dirty_i->seglist_lock); 283 284 p.alloc_mode = alloc_mode; 285 select_policy(sbi, gc_type, type, &p); 286 287 p.min_segno = NULL_SEGNO; 288 p.min_cost = get_max_cost(sbi, &p); 289 290 if (p.max_search == 0) 291 goto out; 292 293 last_victim = sbi->last_victim[p.gc_mode]; 294 if (p.alloc_mode == LFS && gc_type == FG_GC) { 295 p.min_segno = check_bg_victims(sbi); 296 if (p.min_segno != NULL_SEGNO) 297 goto got_it; 298 } 299 300 while (1) { 301 unsigned long cost; 302 unsigned int segno; 303 304 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset); 305 if (segno >= last_segment) { 306 if (sbi->last_victim[p.gc_mode]) { 307 last_segment = sbi->last_victim[p.gc_mode]; 308 sbi->last_victim[p.gc_mode] = 0; 309 p.offset = 0; 310 continue; 311 } 312 break; 313 } 314 315 p.offset = segno + p.ofs_unit; 316 if (p.ofs_unit > 1) { 317 p.offset -= segno % p.ofs_unit; 318 nsearched += count_bits(p.dirty_segmap, 319 p.offset - p.ofs_unit, 320 p.ofs_unit); 321 } else { 322 nsearched++; 323 } 324 325 326 secno = GET_SECNO(sbi, segno); 327 328 if (sec_usage_check(sbi, secno)) 329 goto next; 330 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap)) 331 goto next; 332 333 cost = get_gc_cost(sbi, segno, &p); 334 335 if (p.min_cost > cost) { 336 p.min_segno = segno; 337 p.min_cost = cost; 338 } 339 next: 340 if (nsearched >= p.max_search) { 341 if (!sbi->last_victim[p.gc_mode] && segno <= last_victim) 342 sbi->last_victim[p.gc_mode] = last_victim + 1; 343 else 344 sbi->last_victim[p.gc_mode] = segno + 1; 345 break; 346 } 347 } 348 if (p.min_segno != NULL_SEGNO) { 349 got_it: 350 if (p.alloc_mode == LFS) { 351 secno = GET_SECNO(sbi, p.min_segno); 352 if (gc_type == FG_GC) 353 sbi->cur_victim_sec = secno; 354 else 355 set_bit(secno, dirty_i->victim_secmap); 356 } 357 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit; 358 359 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p, 360 sbi->cur_victim_sec, 361 prefree_segments(sbi), free_segments(sbi)); 362 } 363 out: 364 mutex_unlock(&dirty_i->seglist_lock); 365 366 return (p.min_segno == NULL_SEGNO) ? 0 : 1; 367 } 368 369 static const struct victim_selection default_v_ops = { 370 .get_victim = get_victim_by_default, 371 }; 372 373 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino) 374 { 375 struct inode_entry *ie; 376 377 ie = radix_tree_lookup(&gc_list->iroot, ino); 378 if (ie) 379 return ie->inode; 380 return NULL; 381 } 382 383 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode) 384 { 385 struct inode_entry *new_ie; 386 387 if (inode == find_gc_inode(gc_list, inode->i_ino)) { 388 iput(inode); 389 return; 390 } 391 new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS); 392 new_ie->inode = inode; 393 394 f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie); 395 list_add_tail(&new_ie->list, &gc_list->ilist); 396 } 397 398 static void put_gc_inode(struct gc_inode_list *gc_list) 399 { 400 struct inode_entry *ie, *next_ie; 401 list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) { 402 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino); 403 iput(ie->inode); 404 list_del(&ie->list); 405 kmem_cache_free(inode_entry_slab, ie); 406 } 407 } 408 409 static int check_valid_map(struct f2fs_sb_info *sbi, 410 unsigned int segno, int offset) 411 { 412 struct sit_info *sit_i = SIT_I(sbi); 413 struct seg_entry *sentry; 414 int ret; 415 416 mutex_lock(&sit_i->sentry_lock); 417 sentry = get_seg_entry(sbi, segno); 418 ret = f2fs_test_bit(offset, sentry->cur_valid_map); 419 mutex_unlock(&sit_i->sentry_lock); 420 return ret; 421 } 422 423 /* 424 * This function compares node address got in summary with that in NAT. 425 * On validity, copy that node with cold status, otherwise (invalid node) 426 * ignore that. 427 */ 428 static void gc_node_segment(struct f2fs_sb_info *sbi, 429 struct f2fs_summary *sum, unsigned int segno, int gc_type) 430 { 431 struct f2fs_summary *entry; 432 block_t start_addr; 433 int off; 434 int phase = 0; 435 436 start_addr = START_BLOCK(sbi, segno); 437 438 next_step: 439 entry = sum; 440 441 for (off = 0; off < sbi->blocks_per_seg; off++, entry++) { 442 nid_t nid = le32_to_cpu(entry->nid); 443 struct page *node_page; 444 struct node_info ni; 445 446 /* stop BG_GC if there is not enough free sections. */ 447 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) 448 return; 449 450 if (check_valid_map(sbi, segno, off) == 0) 451 continue; 452 453 if (phase == 0) { 454 ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1, 455 META_NAT, true); 456 continue; 457 } 458 459 if (phase == 1) { 460 ra_node_page(sbi, nid); 461 continue; 462 } 463 464 /* phase == 2 */ 465 node_page = get_node_page(sbi, nid); 466 if (IS_ERR(node_page)) 467 continue; 468 469 /* block may become invalid during get_node_page */ 470 if (check_valid_map(sbi, segno, off) == 0) { 471 f2fs_put_page(node_page, 1); 472 continue; 473 } 474 475 get_node_info(sbi, nid, &ni); 476 if (ni.blk_addr != start_addr + off) { 477 f2fs_put_page(node_page, 1); 478 continue; 479 } 480 481 move_node_page(node_page, gc_type); 482 stat_inc_node_blk_count(sbi, 1, gc_type); 483 } 484 485 if (++phase < 3) 486 goto next_step; 487 } 488 489 /* 490 * Calculate start block index indicating the given node offset. 491 * Be careful, caller should give this node offset only indicating direct node 492 * blocks. If any node offsets, which point the other types of node blocks such 493 * as indirect or double indirect node blocks, are given, it must be a caller's 494 * bug. 495 */ 496 block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode) 497 { 498 unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4; 499 unsigned int bidx; 500 501 if (node_ofs == 0) 502 return 0; 503 504 if (node_ofs <= 2) { 505 bidx = node_ofs - 1; 506 } else if (node_ofs <= indirect_blks) { 507 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1); 508 bidx = node_ofs - 2 - dec; 509 } else { 510 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1); 511 bidx = node_ofs - 5 - dec; 512 } 513 return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode); 514 } 515 516 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, 517 struct node_info *dni, block_t blkaddr, unsigned int *nofs) 518 { 519 struct page *node_page; 520 nid_t nid; 521 unsigned int ofs_in_node; 522 block_t source_blkaddr; 523 524 nid = le32_to_cpu(sum->nid); 525 ofs_in_node = le16_to_cpu(sum->ofs_in_node); 526 527 node_page = get_node_page(sbi, nid); 528 if (IS_ERR(node_page)) 529 return false; 530 531 get_node_info(sbi, nid, dni); 532 533 if (sum->version != dni->version) { 534 f2fs_put_page(node_page, 1); 535 return false; 536 } 537 538 *nofs = ofs_of_node(node_page); 539 source_blkaddr = datablock_addr(node_page, ofs_in_node); 540 f2fs_put_page(node_page, 1); 541 542 if (source_blkaddr != blkaddr) 543 return false; 544 return true; 545 } 546 547 static void move_encrypted_block(struct inode *inode, block_t bidx, 548 unsigned int segno, int off) 549 { 550 struct f2fs_io_info fio = { 551 .sbi = F2FS_I_SB(inode), 552 .type = DATA, 553 .op = REQ_OP_READ, 554 .op_flags = 0, 555 .encrypted_page = NULL, 556 }; 557 struct dnode_of_data dn; 558 struct f2fs_summary sum; 559 struct node_info ni; 560 struct page *page; 561 block_t newaddr; 562 int err; 563 564 /* do not read out */ 565 page = f2fs_grab_cache_page(inode->i_mapping, bidx, false); 566 if (!page) 567 return; 568 569 if (!check_valid_map(F2FS_I_SB(inode), segno, off)) 570 goto out; 571 572 set_new_dnode(&dn, inode, NULL, NULL, 0); 573 err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE); 574 if (err) 575 goto out; 576 577 if (unlikely(dn.data_blkaddr == NULL_ADDR)) { 578 ClearPageUptodate(page); 579 goto put_out; 580 } 581 582 /* 583 * don't cache encrypted data into meta inode until previous dirty 584 * data were writebacked to avoid racing between GC and flush. 585 */ 586 f2fs_wait_on_page_writeback(page, DATA, true); 587 588 get_node_info(fio.sbi, dn.nid, &ni); 589 set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version); 590 591 /* read page */ 592 fio.page = page; 593 fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr; 594 595 allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr, 596 &sum, CURSEG_COLD_DATA); 597 598 fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr, 599 FGP_LOCK | FGP_CREAT, GFP_NOFS); 600 if (!fio.encrypted_page) { 601 err = -ENOMEM; 602 goto recover_block; 603 } 604 605 err = f2fs_submit_page_bio(&fio); 606 if (err) 607 goto put_page_out; 608 609 /* write page */ 610 lock_page(fio.encrypted_page); 611 612 if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) { 613 err = -EIO; 614 goto put_page_out; 615 } 616 if (unlikely(!PageUptodate(fio.encrypted_page))) { 617 err = -EIO; 618 goto put_page_out; 619 } 620 621 set_page_dirty(fio.encrypted_page); 622 f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true); 623 if (clear_page_dirty_for_io(fio.encrypted_page)) 624 dec_page_count(fio.sbi, F2FS_DIRTY_META); 625 626 set_page_writeback(fio.encrypted_page); 627 628 /* allocate block address */ 629 f2fs_wait_on_page_writeback(dn.node_page, NODE, true); 630 631 fio.op = REQ_OP_WRITE; 632 fio.op_flags = REQ_SYNC; 633 fio.new_blkaddr = newaddr; 634 f2fs_submit_page_mbio(&fio); 635 636 f2fs_update_data_blkaddr(&dn, newaddr); 637 set_inode_flag(inode, FI_APPEND_WRITE); 638 if (page->index == 0) 639 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN); 640 put_page_out: 641 f2fs_put_page(fio.encrypted_page, 1); 642 recover_block: 643 if (err) 644 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr, 645 true, true); 646 put_out: 647 f2fs_put_dnode(&dn); 648 out: 649 f2fs_put_page(page, 1); 650 } 651 652 static void move_data_page(struct inode *inode, block_t bidx, int gc_type, 653 unsigned int segno, int off) 654 { 655 struct page *page; 656 657 page = get_lock_data_page(inode, bidx, true); 658 if (IS_ERR(page)) 659 return; 660 661 if (!check_valid_map(F2FS_I_SB(inode), segno, off)) 662 goto out; 663 664 if (gc_type == BG_GC) { 665 if (PageWriteback(page)) 666 goto out; 667 set_page_dirty(page); 668 set_cold_data(page); 669 } else { 670 struct f2fs_io_info fio = { 671 .sbi = F2FS_I_SB(inode), 672 .type = DATA, 673 .op = REQ_OP_WRITE, 674 .op_flags = REQ_SYNC, 675 .page = page, 676 .encrypted_page = NULL, 677 }; 678 bool is_dirty = PageDirty(page); 679 int err; 680 681 retry: 682 set_page_dirty(page); 683 f2fs_wait_on_page_writeback(page, DATA, true); 684 if (clear_page_dirty_for_io(page)) { 685 inode_dec_dirty_pages(inode); 686 remove_dirty_inode(inode); 687 } 688 689 set_cold_data(page); 690 691 err = do_write_data_page(&fio); 692 if (err == -ENOMEM && is_dirty) { 693 congestion_wait(BLK_RW_ASYNC, HZ/50); 694 goto retry; 695 } 696 } 697 out: 698 f2fs_put_page(page, 1); 699 } 700 701 /* 702 * This function tries to get parent node of victim data block, and identifies 703 * data block validity. If the block is valid, copy that with cold status and 704 * modify parent node. 705 * If the parent node is not valid or the data block address is different, 706 * the victim data block is ignored. 707 */ 708 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum, 709 struct gc_inode_list *gc_list, unsigned int segno, int gc_type) 710 { 711 struct super_block *sb = sbi->sb; 712 struct f2fs_summary *entry; 713 block_t start_addr; 714 int off; 715 int phase = 0; 716 717 start_addr = START_BLOCK(sbi, segno); 718 719 next_step: 720 entry = sum; 721 722 for (off = 0; off < sbi->blocks_per_seg; off++, entry++) { 723 struct page *data_page; 724 struct inode *inode; 725 struct node_info dni; /* dnode info for the data */ 726 unsigned int ofs_in_node, nofs; 727 block_t start_bidx; 728 nid_t nid = le32_to_cpu(entry->nid); 729 730 /* stop BG_GC if there is not enough free sections. */ 731 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) 732 return; 733 734 if (check_valid_map(sbi, segno, off) == 0) 735 continue; 736 737 if (phase == 0) { 738 ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1, 739 META_NAT, true); 740 continue; 741 } 742 743 if (phase == 1) { 744 ra_node_page(sbi, nid); 745 continue; 746 } 747 748 /* Get an inode by ino with checking validity */ 749 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs)) 750 continue; 751 752 if (phase == 2) { 753 ra_node_page(sbi, dni.ino); 754 continue; 755 } 756 757 ofs_in_node = le16_to_cpu(entry->ofs_in_node); 758 759 if (phase == 3) { 760 inode = f2fs_iget(sb, dni.ino); 761 if (IS_ERR(inode) || is_bad_inode(inode)) 762 continue; 763 764 /* if encrypted inode, let's go phase 3 */ 765 if (f2fs_encrypted_inode(inode) && 766 S_ISREG(inode->i_mode)) { 767 add_gc_inode(gc_list, inode); 768 continue; 769 } 770 771 start_bidx = start_bidx_of_node(nofs, inode); 772 data_page = get_read_data_page(inode, 773 start_bidx + ofs_in_node, REQ_RAHEAD, 774 true); 775 if (IS_ERR(data_page)) { 776 iput(inode); 777 continue; 778 } 779 780 f2fs_put_page(data_page, 0); 781 add_gc_inode(gc_list, inode); 782 continue; 783 } 784 785 /* phase 4 */ 786 inode = find_gc_inode(gc_list, dni.ino); 787 if (inode) { 788 struct f2fs_inode_info *fi = F2FS_I(inode); 789 bool locked = false; 790 791 if (S_ISREG(inode->i_mode)) { 792 if (!down_write_trylock(&fi->dio_rwsem[READ])) 793 continue; 794 if (!down_write_trylock( 795 &fi->dio_rwsem[WRITE])) { 796 up_write(&fi->dio_rwsem[READ]); 797 continue; 798 } 799 locked = true; 800 } 801 802 start_bidx = start_bidx_of_node(nofs, inode) 803 + ofs_in_node; 804 if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) 805 move_encrypted_block(inode, start_bidx, segno, off); 806 else 807 move_data_page(inode, start_bidx, gc_type, segno, off); 808 809 if (locked) { 810 up_write(&fi->dio_rwsem[WRITE]); 811 up_write(&fi->dio_rwsem[READ]); 812 } 813 814 stat_inc_data_blk_count(sbi, 1, gc_type); 815 } 816 } 817 818 if (++phase < 5) 819 goto next_step; 820 } 821 822 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim, 823 int gc_type) 824 { 825 struct sit_info *sit_i = SIT_I(sbi); 826 int ret; 827 828 mutex_lock(&sit_i->sentry_lock); 829 ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, 830 NO_CHECK_TYPE, LFS); 831 mutex_unlock(&sit_i->sentry_lock); 832 return ret; 833 } 834 835 static int do_garbage_collect(struct f2fs_sb_info *sbi, 836 unsigned int start_segno, 837 struct gc_inode_list *gc_list, int gc_type) 838 { 839 struct page *sum_page; 840 struct f2fs_summary_block *sum; 841 struct blk_plug plug; 842 unsigned int segno = start_segno; 843 unsigned int end_segno = start_segno + sbi->segs_per_sec; 844 int sec_freed = 0; 845 unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ? 846 SUM_TYPE_DATA : SUM_TYPE_NODE; 847 848 /* readahead multi ssa blocks those have contiguous address */ 849 if (sbi->segs_per_sec > 1) 850 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), 851 sbi->segs_per_sec, META_SSA, true); 852 853 /* reference all summary page */ 854 while (segno < end_segno) { 855 sum_page = get_sum_page(sbi, segno++); 856 unlock_page(sum_page); 857 } 858 859 blk_start_plug(&plug); 860 861 for (segno = start_segno; segno < end_segno; segno++) { 862 863 /* find segment summary of victim */ 864 sum_page = find_get_page(META_MAPPING(sbi), 865 GET_SUM_BLOCK(sbi, segno)); 866 f2fs_put_page(sum_page, 0); 867 868 if (get_valid_blocks(sbi, segno, 1) == 0 || 869 !PageUptodate(sum_page) || 870 unlikely(f2fs_cp_error(sbi))) 871 goto next; 872 873 sum = page_address(sum_page); 874 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer))); 875 876 /* 877 * this is to avoid deadlock: 878 * - lock_page(sum_page) - f2fs_replace_block 879 * - check_valid_map() - mutex_lock(sentry_lock) 880 * - mutex_lock(sentry_lock) - change_curseg() 881 * - lock_page(sum_page) 882 */ 883 884 if (type == SUM_TYPE_NODE) 885 gc_node_segment(sbi, sum->entries, segno, gc_type); 886 else 887 gc_data_segment(sbi, sum->entries, gc_list, segno, 888 gc_type); 889 890 stat_inc_seg_count(sbi, type, gc_type); 891 next: 892 f2fs_put_page(sum_page, 0); 893 } 894 895 if (gc_type == FG_GC) 896 f2fs_submit_merged_bio(sbi, 897 (type == SUM_TYPE_NODE) ? NODE : DATA, WRITE); 898 899 blk_finish_plug(&plug); 900 901 if (gc_type == FG_GC && 902 get_valid_blocks(sbi, start_segno, sbi->segs_per_sec) == 0) 903 sec_freed = 1; 904 905 stat_inc_call_count(sbi->stat_info); 906 907 return sec_freed; 908 } 909 910 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync, bool background) 911 { 912 unsigned int segno; 913 int gc_type = sync ? FG_GC : BG_GC; 914 int sec_freed = 0; 915 int ret = -EINVAL; 916 struct cp_control cpc; 917 struct gc_inode_list gc_list = { 918 .ilist = LIST_HEAD_INIT(gc_list.ilist), 919 .iroot = RADIX_TREE_INIT(GFP_NOFS), 920 }; 921 922 cpc.reason = __get_cp_reason(sbi); 923 gc_more: 924 segno = NULL_SEGNO; 925 926 if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE))) 927 goto stop; 928 if (unlikely(f2fs_cp_error(sbi))) { 929 ret = -EIO; 930 goto stop; 931 } 932 933 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed, 0)) { 934 gc_type = FG_GC; 935 /* 936 * If there is no victim and no prefree segment but still not 937 * enough free sections, we should flush dent/node blocks and do 938 * garbage collections. 939 */ 940 if (__get_victim(sbi, &segno, gc_type) || 941 prefree_segments(sbi)) { 942 ret = write_checkpoint(sbi, &cpc); 943 if (ret) 944 goto stop; 945 segno = NULL_SEGNO; 946 } else if (has_not_enough_free_secs(sbi, 0, 0)) { 947 ret = write_checkpoint(sbi, &cpc); 948 if (ret) 949 goto stop; 950 } 951 } else if (gc_type == BG_GC && !background) { 952 /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */ 953 goto stop; 954 } 955 956 if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type)) 957 goto stop; 958 ret = 0; 959 960 if (do_garbage_collect(sbi, segno, &gc_list, gc_type) && 961 gc_type == FG_GC) 962 sec_freed++; 963 964 if (gc_type == FG_GC) 965 sbi->cur_victim_sec = NULL_SEGNO; 966 967 if (!sync) { 968 if (has_not_enough_free_secs(sbi, sec_freed, 0)) 969 goto gc_more; 970 971 if (gc_type == FG_GC) 972 ret = write_checkpoint(sbi, &cpc); 973 } 974 stop: 975 mutex_unlock(&sbi->gc_mutex); 976 977 put_gc_inode(&gc_list); 978 979 if (sync) 980 ret = sec_freed ? 0 : -EAGAIN; 981 return ret; 982 } 983 984 void build_gc_manager(struct f2fs_sb_info *sbi) 985 { 986 DIRTY_I(sbi)->v_ops = &default_v_ops; 987 } 988