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 list_head *this;
 325         struct inode_entry *ie;
 326
 327         list_for_each(this, ilist) {
 328                 ie = list_entry(this, struct inode_entry, list);
 329                 if (ie->inode->i_ino == ino)
 330                         return ie->inode;
 331         }
 332         return NULL;
 333 }
 334
 335 static void add_gc_inode(struct inode *inode, struct list_head *ilist)
 336 {
 337         struct list_head *this;
 338         struct inode_entry *new_ie, *ie;
 339
 340         list_for_each(this, ilist) {
 341                 ie = list_entry(this, struct inode_entry, list);
 342                 if (ie->inode == inode) {
 343                         iput(inode);
 344                         return;
 345                 }
 346         }
 347 repeat:
 348         new_ie = kmem_cache_alloc(winode_slab, GFP_NOFS);
 349         if (!new_ie) {
 350                 cond_resched();
 351                 goto repeat;
 352         }
 353         new_ie->inode = inode;
 354         list_add_tail(&new_ie->list, ilist);
 355 }
 356
 357 static void put_gc_inode(struct list_head *ilist)
 358 {
 359         struct inode_entry *ie, *next_ie;
 360         list_for_each_entry_safe(ie, next_ie, ilist, list) {
 361                 iput(ie->inode);
 362                 list_del(&ie->list);
 363                 kmem_cache_free(winode_slab, ie);
 364         }
 365 }
 366
 367 static int check_valid_map(struct f2fs_sb_info *sbi,
 368                                 unsigned int segno, int offset)
 369 {
 370         struct sit_info *sit_i = SIT_I(sbi);
 371         struct seg_entry *sentry;
 372         int ret;
 373
 374         mutex_lock(&sit_i->sentry_lock);
 375         sentry = get_seg_entry(sbi, segno);
 376         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 377         mutex_unlock(&sit_i->sentry_lock);
 378         return ret;
 379 }
 380
 381 /*
 382  * This function compares node address got in summary with that in NAT.
 383  * On validity, copy that node with cold status, otherwise (invalid node)
 384  * ignore that.
 385  */
 386 static void gc_node_segment(struct f2fs_sb_info *sbi,
 387                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 388 {
 389         bool initial = true;
 390         struct f2fs_summary *entry;
 391         int off;
 392
 393 next_step:
 394         entry = sum;
 395
 396         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 397                 nid_t nid = le32_to_cpu(entry->nid);
 398                 struct page *node_page;
 399
 400                 /* stop BG_GC if there is not enough free sections. */
 401                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 402                         return;
 403
 404                 if (check_valid_map(sbi, segno, off) == 0)
 405                         continue;
 406
 407                 if (initial) {
 408                         ra_node_page(sbi, nid);
 409                         continue;
 410                 }
 411                 node_page = get_node_page(sbi, nid);
 412                 if (IS_ERR(node_page))
 413                         continue;
 414
 415                 /* set page dirty and write it */
 416                 if (gc_type == FG_GC) {
 417                         f2fs_submit_bio(sbi, NODE, true);
 418                         wait_on_page_writeback(node_page);
 419                         set_page_dirty(node_page);
 420                 } else {
 421                         if (!PageWriteback(node_page))
 422                                 set_page_dirty(node_page);
 423                 }
 424                 f2fs_put_page(node_page, 1);
 425                 stat_inc_node_blk_count(sbi, 1);
 426         }
 427
 428         if (initial) {
 429                 initial = false;
 430                 goto next_step;
 431         }
 432
 433         if (gc_type == FG_GC) {
 434                 struct writeback_control wbc = {
 435                         .sync_mode = WB_SYNC_ALL,
 436                         .nr_to_write = LONG_MAX,
 437                         .for_reclaim = 0,
 438                 };
 439                 sync_node_pages(sbi, 0, &wbc);
 440
 441                 /*
 442                  * In the case of FG_GC, it'd be better to reclaim this victim
 443                  * completely.
 444                  */
 445                 if (get_valid_blocks(sbi, segno, 1) != 0)
 446                         goto next_step;
 447         }
 448 }
 449
 450 /*
 451  * Calculate start block index indicating the given node offset.
 452  * Be careful, caller should give this node offset only indicating direct node
 453  * blocks. If any node offsets, which point the other types of node blocks such
 454  * as indirect or double indirect node blocks, are given, it must be a caller's
 455  * bug.
 456  */
 457 block_t start_bidx_of_node(unsigned int node_ofs)
 458 {
 459         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 460         unsigned int bidx;
 461
 462         if (node_ofs == 0)
 463                 return 0;
 464
 465         if (node_ofs <= 2) {
 466                 bidx = node_ofs - 1;
 467         } else if (node_ofs <= indirect_blks) {
 468                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 469                 bidx = node_ofs - 2 - dec;
 470         } else {
 471                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 472                 bidx = node_ofs - 5 - dec;
 473         }
 474         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE;
 475 }
 476
 477 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 478                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 479 {
 480         struct page *node_page;
 481         nid_t nid;
 482         unsigned int ofs_in_node;
 483         block_t source_blkaddr;
 484
 485         nid = le32_to_cpu(sum->nid);
 486         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 487
 488         node_page = get_node_page(sbi, nid);
 489         if (IS_ERR(node_page))
 490                 return 0;
 491
 492         get_node_info(sbi, nid, dni);
 493
 494         if (sum->version != dni->version) {
 495                 f2fs_put_page(node_page, 1);
 496                 return 0;
 497         }
 498
 499         *nofs = ofs_of_node(node_page);
 500         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 501         f2fs_put_page(node_page, 1);
 502
 503         if (source_blkaddr != blkaddr)
 504                 return 0;
 505         return 1;
 506 }
 507
 508 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
 509 {
 510         if (gc_type == BG_GC) {
 511                 if (PageWriteback(page))
 512                         goto out;
 513                 set_page_dirty(page);
 514                 set_cold_data(page);
 515         } else {
 516                 struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 517
 518                 if (PageWriteback(page)) {
 519                         f2fs_submit_bio(sbi, DATA, true);
 520                         wait_on_page_writeback(page);
 521                 }
 522
 523                 if (clear_page_dirty_for_io(page) &&
 524                         S_ISDIR(inode->i_mode)) {
 525                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 526                         inode_dec_dirty_dents(inode);
 527                 }
 528                 set_cold_data(page);
 529                 do_write_data_page(page);
 530                 clear_cold_data(page);
 531         }
 532 out:
 533         f2fs_put_page(page, 1);
 534 }
 535
 536 /*
 537  * This function tries to get parent node of victim data block, and identifies
 538  * data block validity. If the block is valid, copy that with cold status and
 539  * modify parent node.
 540  * If the parent node is not valid or the data block address is different,
 541  * the victim data block is ignored.
 542  */
 543 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 544                 struct list_head *ilist, unsigned int segno, int gc_type)
 545 {
 546         struct super_block *sb = sbi->sb;
 547         struct f2fs_summary *entry;
 548         block_t start_addr;
 549         int off;
 550         int phase = 0;
 551
 552         start_addr = START_BLOCK(sbi, segno);
 553
 554 next_step:
 555         entry = sum;
 556
 557         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 558                 struct page *data_page;
 559                 struct inode *inode;
 560                 struct node_info dni; /* dnode info for the data */
 561                 unsigned int ofs_in_node, nofs;
 562                 block_t start_bidx;
 563
 564                 /* stop BG_GC if there is not enough free sections. */
 565                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 566                         return;
 567
 568                 if (check_valid_map(sbi, segno, off) == 0)
 569                         continue;
 570
 571                 if (phase == 0) {
 572                         ra_node_page(sbi, le32_to_cpu(entry->nid));
 573                         continue;
 574                 }
 575
 576                 /* Get an inode by ino with checking validity */
 577                 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
 578                         continue;
 579
 580                 if (phase == 1) {
 581                         ra_node_page(sbi, dni.ino);
 582                         continue;
 583                 }
 584
 585                 start_bidx = start_bidx_of_node(nofs);
 586                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 587
 588                 if (phase == 2) {
 589                         inode = f2fs_iget(sb, dni.ino);
 590                         if (IS_ERR(inode))
 591                                 continue;
 592
 593                         data_page = find_data_page(inode,
 594                                         start_bidx + ofs_in_node, false);
 595                         if (IS_ERR(data_page))
 596                                 goto next_iput;
 597
 598                         f2fs_put_page(data_page, 0);
 599                         add_gc_inode(inode, ilist);
 600                 } else {
 601                         inode = find_gc_inode(dni.ino, ilist);
 602                         if (inode) {
 603                                 data_page = get_lock_data_page(inode,
 604                                                 start_bidx + ofs_in_node);
 605                                 if (IS_ERR(data_page))
 606                                         continue;
 607                                 move_data_page(inode, data_page, gc_type);
 608                                 stat_inc_data_blk_count(sbi, 1);
 609                         }
 610                 }
 611                 continue;
 612 next_iput:
 613                 iput(inode);
 614         }
 615
 616         if (++phase < 4)
 617                 goto next_step;
 618
 619         if (gc_type == FG_GC) {
 620                 f2fs_submit_bio(sbi, DATA, true);
 621
 622                 /*
 623                  * In the case of FG_GC, it'd be better to reclaim this victim
 624                  * completely.
 625                  */
 626                 if (get_valid_blocks(sbi, segno, 1) != 0) {
 627                         phase = 2;
 628                         goto next_step;
 629                 }
 630         }
 631 }
 632
 633 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 634                                                 int gc_type, int type)
 635 {
 636         struct sit_info *sit_i = SIT_I(sbi);
 637         int ret;
 638         mutex_lock(&sit_i->sentry_lock);
 639         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
 640         mutex_unlock(&sit_i->sentry_lock);
 641         return ret;
 642 }
 643
 644 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
 645                                 struct list_head *ilist, int gc_type)
 646 {
 647         struct page *sum_page;
 648         struct f2fs_summary_block *sum;
 649         struct blk_plug plug;
 650
 651         /* read segment summary of victim */
 652         sum_page = get_sum_page(sbi, segno);
 653         if (IS_ERR(sum_page))
 654                 return;
 655
 656         blk_start_plug(&plug);
 657
 658         sum = page_address(sum_page);
 659
 660         switch (GET_SUM_TYPE((&sum->footer))) {
 661         case SUM_TYPE_NODE:
 662                 gc_node_segment(sbi, sum->entries, segno, gc_type);
 663                 break;
 664         case SUM_TYPE_DATA:
 665                 gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
 666                 break;
 667         }
 668         blk_finish_plug(&plug);
 669
 670         stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
 671         stat_inc_call_count(sbi->stat_info);
 672
 673         f2fs_put_page(sum_page, 1);
 674 }
 675
 676 int f2fs_gc(struct f2fs_sb_info *sbi)
 677 {
 678         struct list_head ilist;
 679         unsigned int segno, i;
 680         int gc_type = BG_GC;
 681         int nfree = 0;
 682         int ret = -1;
 683
 684         INIT_LIST_HEAD(&ilist);
 685 gc_more:
 686         if (!(sbi->sb->s_flags & MS_ACTIVE))
 687                 goto stop;
 688
 689         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
 690                 gc_type = FG_GC;
 691                 write_checkpoint(sbi, false);
 692         }
 693
 694         if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
 695                 goto stop;
 696         ret = 0;
 697
 698         for (i = 0; i < sbi->segs_per_sec; i++)
 699                 do_garbage_collect(sbi, segno + i, &ilist, gc_type);
 700
 701         if (gc_type == FG_GC) {
 702                 sbi->cur_victim_sec = NULL_SEGNO;
 703                 nfree++;
 704                 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
 705         }
 706
 707         if (has_not_enough_free_secs(sbi, nfree))
 708                 goto gc_more;
 709
 710         if (gc_type == FG_GC)
 711                 write_checkpoint(sbi, false);
 712 stop:
 713         mutex_unlock(&sbi->gc_mutex);
 714
 715         put_gc_inode(&ilist);
 716         return ret;
 717 }
 718
 719 void build_gc_manager(struct f2fs_sb_info *sbi)
 720 {
 721         DIRTY_I(sbi)->v_ops = &default_v_ops;
 722 }
 723
 724 int __init create_gc_caches(void)
 725 {
 726         winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
 727                         sizeof(struct inode_entry), NULL);
 728         if (!winode_slab)
 729                 return -ENOMEM;
 730         return 0;
 731 }
 732
 733 void destroy_gc_caches(void)
 734 {
 735         kmem_cache_destroy(winode_slab);
 736 }