fs/f2fs/gc.c

   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 #include <linux/blkdev.h>
  20
  21 #include "f2fs.h"
  22 #include "node.h"
  23 #include "segment.h"
  24 #include "gc.h"
  25 #include <trace/events/f2fs.h>
  26
  27 static struct kmem_cache *winode_slab;
  28
  29 static int gc_thread_func(void *data)
  30 {
  31         struct f2fs_sb_info *sbi = data;
  32         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
  33         long wait_ms;
  34
  35         wait_ms = GC_THREAD_MIN_SLEEP_TIME;
  36
  37         do {
  38                 if (try_to_freeze())
  39                         continue;
  40                 else
  41                         wait_event_interruptible_timeout(*wq,
  42                                                 kthread_should_stop(),
  43                                                 msecs_to_jiffies(wait_ms));
  44                 if (kthread_should_stop())
  45                         break;
  46
  47                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
  48                         wait_ms = GC_THREAD_MAX_SLEEP_TIME;
  49                         continue;
  50                 }
  51
  52                 /*
  53                  * [GC triggering condition]
  54                  * 0. GC is not conducted currently.
  55                  * 1. There are enough dirty segments.
  56                  * 2. IO subsystem is idle by checking the # of writeback pages.
  57                  * 3. IO subsystem is idle by checking the # of requests in
  58                  *    bdev's request list.
  59                  *
  60                  * Note) We have to avoid triggering GCs too much frequently.
  61                  * Because it is possible that some segments can be
  62                  * invalidated soon after by user update or deletion.
  63                  * So, I'd like to wait some time to collect dirty segments.
  64                  */
  65                 if (!mutex_trylock(&sbi->gc_mutex))
  66                         continue;
  67
  68                 if (!is_idle(sbi)) {
  69                         wait_ms = increase_sleep_time(wait_ms);
  70                         mutex_unlock(&sbi->gc_mutex);
  71                         continue;
  72                 }
  73
  74                 if (has_enough_invalid_blocks(sbi))
  75                         wait_ms = decrease_sleep_time(wait_ms);
  76                 else
  77                         wait_ms = increase_sleep_time(wait_ms);
  78
  79 #ifdef CONFIG_F2FS_STAT_FS
  80                 sbi->bg_gc++;
  81 #endif
  82
  83                 /* if return value is not zero, no victim was selected */
  84                 if (f2fs_gc(sbi))
  85                         wait_ms = GC_THREAD_NOGC_SLEEP_TIME;
  86         } while (!kthread_should_stop());
  87         return 0;
  88 }
  89
  90 int start_gc_thread(struct f2fs_sb_info *sbi)
  91 {
  92         struct f2fs_gc_kthread *gc_th;
  93         dev_t dev = sbi->sb->s_bdev->bd_dev;
  94         int err = 0;
  95
  96         if (!test_opt(sbi, BG_GC))
  97                 goto out;
  98         gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
  99         if (!gc_th) {
 100                 err = -ENOMEM;
 101                 goto out;
 102         }
 103
 104         sbi->gc_thread = gc_th;
 105         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 106         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 107                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 108         if (IS_ERR(gc_th->f2fs_gc_task)) {
 109                 err = PTR_ERR(gc_th->f2fs_gc_task);
 110                 kfree(gc_th);
 111                 sbi->gc_thread = NULL;
 112         }
 113
 114 out:
 115         return err;
 116 }
 117
 118 void stop_gc_thread(struct f2fs_sb_info *sbi)
 119 {
 120         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 121         if (!gc_th)
 122                 return;
 123         kthread_stop(gc_th->f2fs_gc_task);
 124         kfree(gc_th);
 125         sbi->gc_thread = NULL;
 126 }
 127
 128 static int select_gc_type(int gc_type)
 129 {
 130         return (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 131 }
 132
 133 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 134                         int type, struct victim_sel_policy *p)
 135 {
 136         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 137
 138         if (p->alloc_mode == SSR) {
 139                 p->gc_mode = GC_GREEDY;
 140                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 141                 p->ofs_unit = 1;
 142         } else {
 143                 p->gc_mode = select_gc_type(gc_type);
 144                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 145                 p->ofs_unit = sbi->segs_per_sec;
 146         }
 147         p->offset = sbi->last_victim[p->gc_mode];
 148 }
 149
 150 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 151                                 struct victim_sel_policy *p)
 152 {
 153         /* SSR allocates in a segment unit */
 154         if (p->alloc_mode == SSR)
 155                 return 1 << sbi->log_blocks_per_seg;
 156         if (p->gc_mode == GC_GREEDY)
 157                 return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
 158         else if (p->gc_mode == GC_CB)
 159                 return UINT_MAX;
 160         else /* No other gc_mode */
 161                 return 0;
 162 }
 163
 164 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 165 {
 166         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 167         unsigned int hint = 0;
 168         unsigned int secno;
 169
 170         /*
 171          * If the gc_type is FG_GC, we can select victim segments
 172          * selected by background GC before.
 173          * Those segments guarantee they have small valid blocks.
 174          */
 175 next:
 176         secno = find_next_bit(dirty_i->victim_secmap, TOTAL_SECS(sbi), hint++);
 177         if (secno < TOTAL_SECS(sbi)) {
 178                 if (sec_usage_check(sbi, secno))
 179                         goto next;
 180                 clear_bit(secno, dirty_i->victim_secmap);
 181                 return secno * sbi->segs_per_sec;
 182         }
 183         return NULL_SEGNO;
 184 }
 185
 186 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 187 {
 188         struct sit_info *sit_i = SIT_I(sbi);
 189         unsigned int secno = GET_SECNO(sbi, segno);
 190         unsigned int start = secno * sbi->segs_per_sec;
 191         unsigned long long mtime = 0;
 192         unsigned int vblocks;
 193         unsigned char age = 0;
 194         unsigned char u;
 195         unsigned int i;
 196
 197         for (i = 0; i < sbi->segs_per_sec; i++)
 198                 mtime += get_seg_entry(sbi, start + i)->mtime;
 199         vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 200
 201         mtime = div_u64(mtime, sbi->segs_per_sec);
 202         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 203
 204         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 205
 206         /* Handle if the system time is changed by user */
 207         if (mtime < sit_i->min_mtime)
 208                 sit_i->min_mtime = mtime;
 209         if (mtime > sit_i->max_mtime)
 210                 sit_i->max_mtime = mtime;
 211         if (sit_i->max_mtime != sit_i->min_mtime)
 212                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 213                                 sit_i->max_mtime - sit_i->min_mtime);
 214
 215         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 216 }
 217
 218 static unsigned int get_gc_cost(struct f2fs_sb_info *sbi, unsigned int segno,
 219                                         struct victim_sel_policy *p)
 220 {
 221         if (p->alloc_mode == SSR)
 222                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 223
 224         /* alloc_mode == LFS */
 225         if (p->gc_mode == GC_GREEDY)
 226                 return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 227         else
 228                 return get_cb_cost(sbi, segno);
 229 }
 230
 231 /*
 232  * This function is called from two paths.
 233  * One is garbage collection and the other is SSR segment selection.
 234  * When it is called during GC, it just gets a victim segment
 235  * and it does not remove it from dirty seglist.
 236  * When it is called from SSR segment selection, it finds a segment
 237  * which has minimum valid blocks and removes it from dirty seglist.
 238  */
 239 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 240                 unsigned int *result, int gc_type, int type, char alloc_mode)
 241 {
 242         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 243         struct victim_sel_policy p;
 244         unsigned int secno, max_cost;
 245         int nsearched = 0;
 246
 247         p.alloc_mode = alloc_mode;
 248         select_policy(sbi, gc_type, type, &p);
 249
 250         p.min_segno = NULL_SEGNO;
 251         p.min_cost = max_cost = get_max_cost(sbi, &p);
 252
 253         mutex_lock(&dirty_i->seglist_lock);
 254
 255         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 256                 p.min_segno = check_bg_victims(sbi);
 257                 if (p.min_segno != NULL_SEGNO)
 258                         goto got_it;
 259         }
 260
 261         while (1) {
 262                 unsigned long cost;
 263                 unsigned int segno;
 264
 265                 segno = find_next_bit(p.dirty_segmap,
 266                                                 TOTAL_SEGS(sbi), p.offset);
 267                 if (segno >= TOTAL_SEGS(sbi)) {
 268                         if (sbi->last_victim[p.gc_mode]) {
 269                                 sbi->last_victim[p.gc_mode] = 0;
 270                                 p.offset = 0;
 271                                 continue;
 272                         }
 273                         break;
 274                 }
 275                 p.offset = ((segno / p.ofs_unit) * p.ofs_unit) + p.ofs_unit;
 276                 secno = GET_SECNO(sbi, segno);
 277
 278                 if (sec_usage_check(sbi, secno))
 279                         continue;
 280                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 281                         continue;
 282
 283                 cost = get_gc_cost(sbi, segno, &p);
 284
 285                 if (p.min_cost > cost) {
 286                         p.min_segno = segno;
 287                         p.min_cost = cost;
 288                 }
 289
 290                 if (cost == max_cost)
 291                         continue;
 292
 293                 if (nsearched++ >= MAX_VICTIM_SEARCH) {
 294                         sbi->last_victim[p.gc_mode] = segno;
 295                         break;
 296                 }
 297         }
 298         if (p.min_segno != NULL_SEGNO) {
 299 got_it:
 300                 if (p.alloc_mode == LFS) {
 301                         secno = GET_SECNO(sbi, p.min_segno);
 302                         if (gc_type == FG_GC)
 303                                 sbi->cur_victim_sec = secno;
 304                         else
 305                                 set_bit(secno, dirty_i->victim_secmap);
 306                 }
 307                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 308
 309                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 310                                 sbi->cur_victim_sec,
 311                                 prefree_segments(sbi), free_segments(sbi));
 312         }
 313         mutex_unlock(&dirty_i->seglist_lock);
 314
 315         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 316 }
 317
 318 static const struct victim_selection default_v_ops = {
 319         .get_victim = get_victim_by_default,
 320 };
 321
 322 static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
 323 {
 324         struct inode_entry *ie;
 325
 326         list_for_each_entry(ie, ilist, list)
 327                 if (ie->inode->i_ino == ino)
 328                         return ie->inode;
 329         return NULL;
 330 }
 331
 332 static void add_gc_inode(struct inode *inode, struct list_head *ilist)
 333 {
 334         struct inode_entry *new_ie;
 335
 336         if (inode == find_gc_inode(inode->i_ino, ilist)) {
 337                 iput(inode);
 338                 return;
 339         }
 340 repeat:
 341         new_ie = kmem_cache_alloc(winode_slab, GFP_NOFS);
 342         if (!new_ie) {
 343                 cond_resched();
 344                 goto repeat;
 345         }
 346         new_ie->inode = inode;
 347         list_add_tail(&new_ie->list, ilist);
 348 }
 349
 350 static void put_gc_inode(struct list_head *ilist)
 351 {
 352         struct inode_entry *ie, *next_ie;
 353         list_for_each_entry_safe(ie, next_ie, ilist, list) {
 354                 iput(ie->inode);
 355                 list_del(&ie->list);
 356                 kmem_cache_free(winode_slab, ie);
 357         }
 358 }
 359
 360 static int check_valid_map(struct f2fs_sb_info *sbi,
 361                                 unsigned int segno, int offset)
 362 {
 363         struct sit_info *sit_i = SIT_I(sbi);
 364         struct seg_entry *sentry;
 365         int ret;
 366
 367         mutex_lock(&sit_i->sentry_lock);
 368         sentry = get_seg_entry(sbi, segno);
 369         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 370         mutex_unlock(&sit_i->sentry_lock);
 371         return ret;
 372 }
 373
 374 /*
 375  * This function compares node address got in summary with that in NAT.
 376  * On validity, copy that node with cold status, otherwise (invalid node)
 377  * ignore that.
 378  */
 379 static void gc_node_segment(struct f2fs_sb_info *sbi,
 380                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 381 {
 382         bool initial = true;
 383         struct f2fs_summary *entry;
 384         int off;
 385
 386 next_step:
 387         entry = sum;
 388
 389         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 390                 nid_t nid = le32_to_cpu(entry->nid);
 391                 struct page *node_page;
 392
 393                 /* stop BG_GC if there is not enough free sections. */
 394                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 395                         return;
 396
 397                 if (check_valid_map(sbi, segno, off) == 0)
 398                         continue;
 399
 400                 if (initial) {
 401                         ra_node_page(sbi, nid);
 402                         continue;
 403                 }
 404                 node_page = get_node_page(sbi, nid);
 405                 if (IS_ERR(node_page))
 406                         continue;
 407
 408                 /* set page dirty and write it */
 409                 if (gc_type == FG_GC) {
 410                         f2fs_submit_bio(sbi, NODE, true);
 411                         wait_on_page_writeback(node_page);
 412                         set_page_dirty(node_page);
 413                 } else {
 414                         if (!PageWriteback(node_page))
 415                                 set_page_dirty(node_page);
 416                 }
 417                 f2fs_put_page(node_page, 1);
 418                 stat_inc_node_blk_count(sbi, 1);
 419         }
 420
 421         if (initial) {
 422                 initial = false;
 423                 goto next_step;
 424         }
 425
 426         if (gc_type == FG_GC) {
 427                 struct writeback_control wbc = {
 428                         .sync_mode = WB_SYNC_ALL,
 429                         .nr_to_write = LONG_MAX,
 430                         .for_reclaim = 0,
 431                 };
 432                 sync_node_pages(sbi, 0, &wbc);
 433
 434                 /*
 435                  * In the case of FG_GC, it'd be better to reclaim this victim
 436                  * completely.
 437                  */
 438                 if (get_valid_blocks(sbi, segno, 1) != 0)
 439                         goto next_step;
 440         }
 441 }
 442
 443 /*
 444  * Calculate start block index indicating the given node offset.
 445  * Be careful, caller should give this node offset only indicating direct node
 446  * blocks. If any node offsets, which point the other types of node blocks such
 447  * as indirect or double indirect node blocks, are given, it must be a caller's
 448  * bug.
 449  */
 450 block_t start_bidx_of_node(unsigned int node_ofs)
 451 {
 452         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 453         unsigned int bidx;
 454
 455         if (node_ofs == 0)
 456                 return 0;
 457
 458         if (node_ofs <= 2) {
 459                 bidx = node_ofs - 1;
 460         } else if (node_ofs <= indirect_blks) {
 461                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 462                 bidx = node_ofs - 2 - dec;
 463         } else {
 464                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 465                 bidx = node_ofs - 5 - dec;
 466         }
 467         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE;
 468 }
 469
 470 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 471                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 472 {
 473         struct page *node_page;
 474         nid_t nid;
 475         unsigned int ofs_in_node;
 476         block_t source_blkaddr;
 477
 478         nid = le32_to_cpu(sum->nid);
 479         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 480
 481         node_page = get_node_page(sbi, nid);
 482         if (IS_ERR(node_page))
 483                 return 0;
 484
 485         get_node_info(sbi, nid, dni);
 486
 487         if (sum->version != dni->version) {
 488                 f2fs_put_page(node_page, 1);
 489                 return 0;
 490         }
 491
 492         *nofs = ofs_of_node(node_page);
 493         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 494         f2fs_put_page(node_page, 1);
 495
 496         if (source_blkaddr != blkaddr)
 497                 return 0;
 498         return 1;
 499 }
 500
 501 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
 502 {
 503         if (gc_type == BG_GC) {
 504                 if (PageWriteback(page))
 505                         goto out;
 506                 set_page_dirty(page);
 507                 set_cold_data(page);
 508         } else {
 509                 struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 510
 511                 if (PageWriteback(page)) {
 512                         f2fs_submit_bio(sbi, DATA, true);
 513                         wait_on_page_writeback(page);
 514                 }
 515
 516                 if (clear_page_dirty_for_io(page) &&
 517                         S_ISDIR(inode->i_mode)) {
 518                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 519                         inode_dec_dirty_dents(inode);
 520                 }
 521                 set_cold_data(page);
 522                 do_write_data_page(page);
 523                 clear_cold_data(page);
 524         }
 525 out:
 526         f2fs_put_page(page, 1);
 527 }
 528
 529 /*
 530  * This function tries to get parent node of victim data block, and identifies
 531  * data block validity. If the block is valid, copy that with cold status and
 532  * modify parent node.
 533  * If the parent node is not valid or the data block address is different,
 534  * the victim data block is ignored.
 535  */
 536 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 537                 struct list_head *ilist, unsigned int segno, int gc_type)
 538 {
 539         struct super_block *sb = sbi->sb;
 540         struct f2fs_summary *entry;
 541         block_t start_addr;
 542         int off;
 543         int phase = 0;
 544
 545         start_addr = START_BLOCK(sbi, segno);
 546
 547 next_step:
 548         entry = sum;
 549
 550         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 551                 struct page *data_page;
 552                 struct inode *inode;
 553                 struct node_info dni; /* dnode info for the data */
 554                 unsigned int ofs_in_node, nofs;
 555                 block_t start_bidx;
 556
 557                 /* stop BG_GC if there is not enough free sections. */
 558                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 559                         return;
 560
 561                 if (check_valid_map(sbi, segno, off) == 0)
 562                         continue;
 563
 564                 if (phase == 0) {
 565                         ra_node_page(sbi, le32_to_cpu(entry->nid));
 566                         continue;
 567                 }
 568
 569                 /* Get an inode by ino with checking validity */
 570                 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
 571                         continue;
 572
 573                 if (phase == 1) {
 574                         ra_node_page(sbi, dni.ino);
 575                         continue;
 576                 }
 577
 578                 start_bidx = start_bidx_of_node(nofs);
 579                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 580
 581                 if (phase == 2) {
 582                         inode = f2fs_iget(sb, dni.ino);
 583                         if (IS_ERR(inode))
 584                                 continue;
 585
 586                         data_page = find_data_page(inode,
 587                                         start_bidx + ofs_in_node, false);
 588                         if (IS_ERR(data_page))
 589                                 goto next_iput;
 590
 591                         f2fs_put_page(data_page, 0);
 592                         add_gc_inode(inode, ilist);
 593                 } else {
 594                         inode = find_gc_inode(dni.ino, ilist);
 595                         if (inode) {
 596                                 data_page = get_lock_data_page(inode,
 597                                                 start_bidx + ofs_in_node);
 598                                 if (IS_ERR(data_page))
 599                                         continue;
 600                                 move_data_page(inode, data_page, gc_type);
 601                                 stat_inc_data_blk_count(sbi, 1);
 602                         }
 603                 }
 604                 continue;
 605 next_iput:
 606                 iput(inode);
 607         }
 608
 609         if (++phase < 4)
 610                 goto next_step;
 611
 612         if (gc_type == FG_GC) {
 613                 f2fs_submit_bio(sbi, DATA, true);
 614
 615                 /*
 616                  * In the case of FG_GC, it'd be better to reclaim this victim
 617                  * completely.
 618                  */
 619                 if (get_valid_blocks(sbi, segno, 1) != 0) {
 620                         phase = 2;
 621                         goto next_step;
 622                 }
 623         }
 624 }
 625
 626 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 627                                                 int gc_type, int type)
 628 {
 629         struct sit_info *sit_i = SIT_I(sbi);
 630         int ret;
 631         mutex_lock(&sit_i->sentry_lock);
 632         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
 633         mutex_unlock(&sit_i->sentry_lock);
 634         return ret;
 635 }
 636
 637 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
 638                                 struct list_head *ilist, int gc_type)
 639 {
 640         struct page *sum_page;
 641         struct f2fs_summary_block *sum;
 642         struct blk_plug plug;
 643
 644         /* read segment summary of victim */
 645         sum_page = get_sum_page(sbi, segno);
 646         if (IS_ERR(sum_page))
 647                 return;
 648
 649         blk_start_plug(&plug);
 650
 651         sum = page_address(sum_page);
 652
 653         switch (GET_SUM_TYPE((&sum->footer))) {
 654         case SUM_TYPE_NODE:
 655                 gc_node_segment(sbi, sum->entries, segno, gc_type);
 656                 break;
 657         case SUM_TYPE_DATA:
 658                 gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
 659                 break;
 660         }
 661         blk_finish_plug(&plug);
 662
 663         stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
 664         stat_inc_call_count(sbi->stat_info);
 665
 666         f2fs_put_page(sum_page, 1);
 667 }
 668
 669 int f2fs_gc(struct f2fs_sb_info *sbi)
 670 {
 671         struct list_head ilist;
 672         unsigned int segno, i;
 673         int gc_type = BG_GC;
 674         int nfree = 0;
 675         int ret = -1;
 676
 677         INIT_LIST_HEAD(&ilist);
 678 gc_more:
 679         if (!(sbi->sb->s_flags & MS_ACTIVE))
 680                 goto stop;
 681
 682         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
 683                 gc_type = FG_GC;
 684                 write_checkpoint(sbi, false);
 685         }
 686
 687         if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
 688                 goto stop;
 689         ret = 0;
 690
 691         for (i = 0; i < sbi->segs_per_sec; i++)
 692                 do_garbage_collect(sbi, segno + i, &ilist, gc_type);
 693
 694         if (gc_type == FG_GC) {
 695                 sbi->cur_victim_sec = NULL_SEGNO;
 696                 nfree++;
 697                 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
 698         }
 699
 700         if (has_not_enough_free_secs(sbi, nfree))
 701                 goto gc_more;
 702
 703         if (gc_type == FG_GC)
 704                 write_checkpoint(sbi, false);
 705 stop:
 706         mutex_unlock(&sbi->gc_mutex);
 707
 708         put_gc_inode(&ilist);
 709         return ret;
 710 }
 711
 712 void build_gc_manager(struct f2fs_sb_info *sbi)
 713 {
 714         DIRTY_I(sbi)->v_ops = &default_v_ops;
 715 }
 716
 717 int __init create_gc_caches(void)
 718 {
 719         winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
 720                         sizeof(struct inode_entry), NULL);
 721         if (!winode_slab)
 722                 return -ENOMEM;
 723         return 0;
 724 }
 725
 726 void destroy_gc_caches(void)
 727 {
 728         kmem_cache_destroy(winode_slab);
 729 }