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/proc_fs.h>
  15 #include <linux/init.h>
  16 #include <linux/f2fs_fs.h>
  17 #include <linux/kthread.h>
  18 #include <linux/delay.h>
  19 #include <linux/freezer.h>
  20 #include <linux/blkdev.h>
  21
  22 #include "f2fs.h"
  23 #include "node.h"
  24 #include "segment.h"
  25 #include "gc.h"
  26 #include <trace/events/f2fs.h>
  27
  28 static struct kmem_cache *winode_slab;
  29
  30 static int gc_thread_func(void *data)
  31 {
  32         struct f2fs_sb_info *sbi = data;
  33         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
  34         long wait_ms;
  35
  36         wait_ms = GC_THREAD_MIN_SLEEP_TIME;
  37
  38         do {
  39                 if (try_to_freeze())
  40                         continue;
  41                 else
  42                         wait_event_interruptible_timeout(*wq,
  43                                                 kthread_should_stop(),
  44                                                 msecs_to_jiffies(wait_ms));
  45                 if (kthread_should_stop())
  46                         break;
  47
  48                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
  49                         wait_ms = GC_THREAD_MAX_SLEEP_TIME;
  50                         continue;
  51                 }
  52
  53                 /*
  54                  * [GC triggering condition]
  55                  * 0. GC is not conducted currently.
  56                  * 1. There are enough dirty segments.
  57                  * 2. IO subsystem is idle by checking the # of writeback pages.
  58                  * 3. IO subsystem is idle by checking the # of requests in
  59                  *    bdev's request list.
  60                  *
  61                  * Note) We have to avoid triggering GCs too much frequently.
  62                  * Because it is possible that some segments can be
  63                  * invalidated soon after by user update or deletion.
  64                  * So, I'd like to wait some time to collect dirty segments.
  65                  */
  66                 if (!mutex_trylock(&sbi->gc_mutex))
  67                         continue;
  68
  69                 if (!is_idle(sbi)) {
  70                         wait_ms = increase_sleep_time(wait_ms);
  71                         mutex_unlock(&sbi->gc_mutex);
  72                         continue;
  73                 }
  74
  75                 if (has_enough_invalid_blocks(sbi))
  76                         wait_ms = decrease_sleep_time(wait_ms);
  77                 else
  78                         wait_ms = increase_sleep_time(wait_ms);
  79
  80                 sbi->bg_gc++;
  81
  82                 /* if return value is not zero, no victim was selected */
  83                 if (f2fs_gc(sbi))
  84                         wait_ms = GC_THREAD_NOGC_SLEEP_TIME;
  85                 else if (wait_ms == GC_THREAD_NOGC_SLEEP_TIME)
  86                         wait_ms = GC_THREAD_MAX_SLEEP_TIME;
  87
  88         } while (!kthread_should_stop());
  89         return 0;
  90 }
  91
  92 int start_gc_thread(struct f2fs_sb_info *sbi)
  93 {
  94         struct f2fs_gc_kthread *gc_th;
  95         dev_t dev = sbi->sb->s_bdev->bd_dev;
  96
  97         if (!test_opt(sbi, BG_GC))
  98                 return 0;
  99         gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
 100         if (!gc_th)
 101                 return -ENOMEM;
 102
 103         sbi->gc_thread = gc_th;
 104         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 105         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 106                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 107         if (IS_ERR(gc_th->f2fs_gc_task)) {
 108                 kfree(gc_th);
 109                 sbi->gc_thread = NULL;
 110                 return -ENOMEM;
 111         }
 112         return 0;
 113 }
 114
 115 void stop_gc_thread(struct f2fs_sb_info *sbi)
 116 {
 117         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 118         if (!gc_th)
 119                 return;
 120         kthread_stop(gc_th->f2fs_gc_task);
 121         kfree(gc_th);
 122         sbi->gc_thread = NULL;
 123 }
 124
 125 static int select_gc_type(int gc_type)
 126 {
 127         return (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 128 }
 129
 130 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 131                         int type, struct victim_sel_policy *p)
 132 {
 133         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 134
 135         if (p->alloc_mode == SSR) {
 136                 p->gc_mode = GC_GREEDY;
 137                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 138                 p->ofs_unit = 1;
 139         } else {
 140                 p->gc_mode = select_gc_type(gc_type);
 141                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 142                 p->ofs_unit = sbi->segs_per_sec;
 143         }
 144         p->offset = sbi->last_victim[p->gc_mode];
 145 }
 146
 147 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 148                                 struct victim_sel_policy *p)
 149 {
 150         /* SSR allocates in a segment unit */
 151         if (p->alloc_mode == SSR)
 152                 return 1 << sbi->log_blocks_per_seg;
 153         if (p->gc_mode == GC_GREEDY)
 154                 return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
 155         else if (p->gc_mode == GC_CB)
 156                 return UINT_MAX;
 157         else /* No other gc_mode */
 158                 return 0;
 159 }
 160
 161 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 162 {
 163         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 164         unsigned int hint = 0;
 165         unsigned int secno;
 166
 167         /*
 168          * If the gc_type is FG_GC, we can select victim segments
 169          * selected by background GC before.
 170          * Those segments guarantee they have small valid blocks.
 171          */
 172 next:
 173         secno = find_next_bit(dirty_i->victim_secmap, TOTAL_SECS(sbi), hint++);
 174         if (secno < TOTAL_SECS(sbi)) {
 175                 if (sec_usage_check(sbi, secno))
 176                         goto next;
 177                 clear_bit(secno, dirty_i->victim_secmap);
 178                 return secno * sbi->segs_per_sec;
 179         }
 180         return NULL_SEGNO;
 181 }
 182
 183 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 184 {
 185         struct sit_info *sit_i = SIT_I(sbi);
 186         unsigned int secno = GET_SECNO(sbi, segno);
 187         unsigned int start = secno * sbi->segs_per_sec;
 188         unsigned long long mtime = 0;
 189         unsigned int vblocks;
 190         unsigned char age = 0;
 191         unsigned char u;
 192         unsigned int i;
 193
 194         for (i = 0; i < sbi->segs_per_sec; i++)
 195                 mtime += get_seg_entry(sbi, start + i)->mtime;
 196         vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 197
 198         mtime = div_u64(mtime, sbi->segs_per_sec);
 199         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 200
 201         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 202
 203         /* Handle if the system time is changed by user */
 204         if (mtime < sit_i->min_mtime)
 205                 sit_i->min_mtime = mtime;
 206         if (mtime > sit_i->max_mtime)
 207                 sit_i->max_mtime = mtime;
 208         if (sit_i->max_mtime != sit_i->min_mtime)
 209                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 210                                 sit_i->max_mtime - sit_i->min_mtime);
 211
 212         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 213 }
 214
 215 static unsigned int get_gc_cost(struct f2fs_sb_info *sbi, unsigned int segno,
 216                                         struct victim_sel_policy *p)
 217 {
 218         if (p->alloc_mode == SSR)
 219                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 220
 221         /* alloc_mode == LFS */
 222         if (p->gc_mode == GC_GREEDY)
 223                 return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 224         else
 225                 return get_cb_cost(sbi, segno);
 226 }
 227
 228 /*
 229  * This function is called from two paths.
 230  * One is garbage collection and the other is SSR segment selection.
 231  * When it is called during GC, it just gets a victim segment
 232  * and it does not remove it from dirty seglist.
 233  * When it is called from SSR segment selection, it finds a segment
 234  * which has minimum valid blocks and removes it from dirty seglist.
 235  */
 236 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 237                 unsigned int *result, int gc_type, int type, char alloc_mode)
 238 {
 239         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 240         struct victim_sel_policy p;
 241         unsigned int secno;
 242         int nsearched = 0;
 243
 244         p.alloc_mode = alloc_mode;
 245         select_policy(sbi, gc_type, type, &p);
 246
 247         p.min_segno = NULL_SEGNO;
 248         p.min_cost = get_max_cost(sbi, &p);
 249
 250         mutex_lock(&dirty_i->seglist_lock);
 251
 252         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 253                 p.min_segno = check_bg_victims(sbi);
 254                 if (p.min_segno != NULL_SEGNO)
 255                         goto got_it;
 256         }
 257
 258         while (1) {
 259                 unsigned long cost;
 260                 unsigned int segno;
 261
 262                 segno = find_next_bit(p.dirty_segmap,
 263                                                 TOTAL_SEGS(sbi), p.offset);
 264                 if (segno >= TOTAL_SEGS(sbi)) {
 265                         if (sbi->last_victim[p.gc_mode]) {
 266                                 sbi->last_victim[p.gc_mode] = 0;
 267                                 p.offset = 0;
 268                                 continue;
 269                         }
 270                         break;
 271                 }
 272                 p.offset = ((segno / p.ofs_unit) * p.ofs_unit) + p.ofs_unit;
 273                 secno = GET_SECNO(sbi, segno);
 274
 275                 if (sec_usage_check(sbi, secno))
 276                         continue;
 277                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 278                         continue;
 279
 280                 cost = get_gc_cost(sbi, segno, &p);
 281
 282                 if (p.min_cost > cost) {
 283                         p.min_segno = segno;
 284                         p.min_cost = cost;
 285                 }
 286
 287                 if (cost == get_max_cost(sbi, &p))
 288                         continue;
 289
 290                 if (nsearched++ >= MAX_VICTIM_SEARCH) {
 291                         sbi->last_victim[p.gc_mode] = segno;
 292                         break;
 293                 }
 294         }
 295 got_it:
 296         if (p.min_segno != NULL_SEGNO) {
 297                 if (p.alloc_mode == LFS) {
 298                         secno = GET_SECNO(sbi, p.min_segno);
 299                         if (gc_type == FG_GC)
 300                                 sbi->cur_victim_sec = secno;
 301                         else
 302                                 set_bit(secno, dirty_i->victim_secmap);
 303                 }
 304                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 305
 306                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 307                                 sbi->cur_victim_sec,
 308                                 prefree_segments(sbi), free_segments(sbi));
 309         }
 310         mutex_unlock(&dirty_i->seglist_lock);
 311
 312         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 313 }
 314
 315 static const struct victim_selection default_v_ops = {
 316         .get_victim = get_victim_by_default,
 317 };
 318
 319 static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
 320 {
 321         struct list_head *this;
 322         struct inode_entry *ie;
 323
 324         list_for_each(this, ilist) {
 325                 ie = list_entry(this, struct inode_entry, list);
 326                 if (ie->inode->i_ino == ino)
 327                         return ie->inode;
 328         }
 329         return NULL;
 330 }
 331
 332 static void add_gc_inode(struct inode *inode, struct list_head *ilist)
 333 {
 334         struct list_head *this;
 335         struct inode_entry *new_ie, *ie;
 336
 337         list_for_each(this, ilist) {
 338                 ie = list_entry(this, struct inode_entry, list);
 339                 if (ie->inode == inode) {
 340                         iput(inode);
 341                         return;
 342                 }
 343         }
 344 repeat:
 345         new_ie = kmem_cache_alloc(winode_slab, GFP_NOFS);
 346         if (!new_ie) {
 347                 cond_resched();
 348                 goto repeat;
 349         }
 350         new_ie->inode = inode;
 351         list_add_tail(&new_ie->list, ilist);
 352 }
 353
 354 static void put_gc_inode(struct list_head *ilist)
 355 {
 356         struct inode_entry *ie, *next_ie;
 357         list_for_each_entry_safe(ie, next_ie, ilist, list) {
 358                 iput(ie->inode);
 359                 list_del(&ie->list);
 360                 kmem_cache_free(winode_slab, ie);
 361         }
 362 }
 363
 364 static int check_valid_map(struct f2fs_sb_info *sbi,
 365                                 unsigned int segno, int offset)
 366 {
 367         struct sit_info *sit_i = SIT_I(sbi);
 368         struct seg_entry *sentry;
 369         int ret;
 370
 371         mutex_lock(&sit_i->sentry_lock);
 372         sentry = get_seg_entry(sbi, segno);
 373         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 374         mutex_unlock(&sit_i->sentry_lock);
 375         return ret;
 376 }
 377
 378 /*
 379  * This function compares node address got in summary with that in NAT.
 380  * On validity, copy that node with cold status, otherwise (invalid node)
 381  * ignore that.
 382  */
 383 static void gc_node_segment(struct f2fs_sb_info *sbi,
 384                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 385 {
 386         bool initial = true;
 387         struct f2fs_summary *entry;
 388         int off;
 389
 390 next_step:
 391         entry = sum;
 392         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 393                 nid_t nid = le32_to_cpu(entry->nid);
 394                 struct page *node_page;
 395
 396                 /* stop BG_GC if there is not enough free sections. */
 397                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 398                         return;
 399
 400                 if (check_valid_map(sbi, segno, off) == 0)
 401                         continue;
 402
 403                 if (initial) {
 404                         ra_node_page(sbi, nid);
 405                         continue;
 406                 }
 407                 node_page = get_node_page(sbi, nid);
 408                 if (IS_ERR(node_page))
 409                         continue;
 410
 411                 /* set page dirty and write it */
 412                 if (gc_type == FG_GC) {
 413                         f2fs_submit_bio(sbi, NODE, true);
 414                         wait_on_page_writeback(node_page);
 415                         set_page_dirty(node_page);
 416                 } else {
 417                         if (!PageWriteback(node_page))
 418                                 set_page_dirty(node_page);
 419                 }
 420                 f2fs_put_page(node_page, 1);
 421                 stat_inc_node_blk_count(sbi, 1);
 422         }
 423         if (initial) {
 424                 initial = false;
 425                 goto next_step;
 426         }
 427
 428         if (gc_type == FG_GC) {
 429                 struct writeback_control wbc = {
 430                         .sync_mode = WB_SYNC_ALL,
 431                         .nr_to_write = LONG_MAX,
 432                         .for_reclaim = 0,
 433                 };
 434                 sync_node_pages(sbi, 0, &wbc);
 435
 436                 /*
 437                  * In the case of FG_GC, it'd be better to reclaim this victim
 438                  * completely.
 439                  */
 440                 if (get_valid_blocks(sbi, segno, 1) != 0)
 441                         goto next_step;
 442         }
 443 }
 444
 445 /*
 446  * Calculate start block index indicating the given node offset.
 447  * Be careful, caller should give this node offset only indicating direct node
 448  * blocks. If any node offsets, which point the other types of node blocks such
 449  * as indirect or double indirect node blocks, are given, it must be a caller's
 450  * bug.
 451  */
 452 block_t start_bidx_of_node(unsigned int node_ofs)
 453 {
 454         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 455         unsigned int bidx;
 456
 457         if (node_ofs == 0)
 458                 return 0;
 459
 460         if (node_ofs <= 2) {
 461                 bidx = node_ofs - 1;
 462         } else if (node_ofs <= indirect_blks) {
 463                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 464                 bidx = node_ofs - 2 - dec;
 465         } else {
 466                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 467                 bidx = node_ofs - 5 - dec;
 468         }
 469         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE;
 470 }
 471
 472 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 473                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 474 {
 475         struct page *node_page;
 476         nid_t nid;
 477         unsigned int ofs_in_node;
 478         block_t source_blkaddr;
 479
 480         nid = le32_to_cpu(sum->nid);
 481         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 482
 483         node_page = get_node_page(sbi, nid);
 484         if (IS_ERR(node_page))
 485                 return 0;
 486
 487         get_node_info(sbi, nid, dni);
 488
 489         if (sum->version != dni->version) {
 490                 f2fs_put_page(node_page, 1);
 491                 return 0;
 492         }
 493
 494         *nofs = ofs_of_node(node_page);
 495         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 496         f2fs_put_page(node_page, 1);
 497
 498         if (source_blkaddr != blkaddr)
 499                 return 0;
 500         return 1;
 501 }
 502
 503 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
 504 {
 505         if (gc_type == BG_GC) {
 506                 if (PageWriteback(page))
 507                         goto out;
 508                 set_page_dirty(page);
 509                 set_cold_data(page);
 510         } else {
 511                 struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 512
 513                 if (PageWriteback(page)) {
 514                         f2fs_submit_bio(sbi, DATA, true);
 515                         wait_on_page_writeback(page);
 516                 }
 517
 518                 if (clear_page_dirty_for_io(page) &&
 519                         S_ISDIR(inode->i_mode)) {
 520                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 521                         inode_dec_dirty_dents(inode);
 522                 }
 523                 set_cold_data(page);
 524                 do_write_data_page(page);
 525                 clear_cold_data(page);
 526         }
 527 out:
 528         f2fs_put_page(page, 1);
 529 }
 530
 531 /*
 532  * This function tries to get parent node of victim data block, and identifies
 533  * data block validity. If the block is valid, copy that with cold status and
 534  * modify parent node.
 535  * If the parent node is not valid or the data block address is different,
 536  * the victim data block is ignored.
 537  */
 538 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 539                 struct list_head *ilist, unsigned int segno, int gc_type)
 540 {
 541         struct super_block *sb = sbi->sb;
 542         struct f2fs_summary *entry;
 543         block_t start_addr;
 544         int off;
 545         int phase = 0;
 546
 547         start_addr = START_BLOCK(sbi, segno);
 548
 549 next_step:
 550         entry = sum;
 551         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 552                 struct page *data_page;
 553                 struct inode *inode;
 554                 struct node_info dni; /* dnode info for the data */
 555                 unsigned int ofs_in_node, nofs;
 556                 block_t start_bidx;
 557
 558                 /* stop BG_GC if there is not enough free sections. */
 559                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 560                         return;
 561
 562                 if (check_valid_map(sbi, segno, off) == 0)
 563                         continue;
 564
 565                 if (phase == 0) {
 566                         ra_node_page(sbi, le32_to_cpu(entry->nid));
 567                         continue;
 568                 }
 569
 570                 /* Get an inode by ino with checking validity */
 571                 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
 572                         continue;
 573
 574                 if (phase == 1) {
 575                         ra_node_page(sbi, dni.ino);
 576                         continue;
 577                 }
 578
 579                 start_bidx = start_bidx_of_node(nofs);
 580                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 581
 582                 if (phase == 2) {
 583                         inode = f2fs_iget(sb, dni.ino);
 584                         if (IS_ERR(inode))
 585                                 continue;
 586
 587                         data_page = find_data_page(inode,
 588                                         start_bidx + ofs_in_node);
 589                         if (IS_ERR(data_page))
 590                                 goto next_iput;
 591
 592                         f2fs_put_page(data_page, 0);
 593                         add_gc_inode(inode, ilist);
 594                 } else {
 595                         inode = find_gc_inode(dni.ino, ilist);
 596                         if (inode) {
 597                                 data_page = get_lock_data_page(inode,
 598                                                 start_bidx + ofs_in_node);
 599                                 if (IS_ERR(data_page))
 600                                         continue;
 601                                 move_data_page(inode, data_page, gc_type);
 602                                 stat_inc_data_blk_count(sbi, 1);
 603                         }
 604                 }
 605                 continue;
 606 next_iput:
 607                 iput(inode);
 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
 643         /* read segment summary of victim */
 644         sum_page = get_sum_page(sbi, segno);
 645         if (IS_ERR(sum_page))
 646                 return;
 647
 648         sum = page_address(sum_page);
 649
 650         switch (GET_SUM_TYPE((&sum->footer))) {
 651         case SUM_TYPE_NODE:
 652                 gc_node_segment(sbi, sum->entries, segno, gc_type);
 653                 break;
 654         case SUM_TYPE_DATA:
 655                 gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
 656                 break;
 657         }
 658         stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
 659         stat_inc_call_count(sbi->stat_info);
 660
 661         f2fs_put_page(sum_page, 1);
 662 }
 663
 664 int f2fs_gc(struct f2fs_sb_info *sbi)
 665 {
 666         struct list_head ilist;
 667         unsigned int segno, i;
 668         int gc_type = BG_GC;
 669         int nfree = 0;
 670         int ret = -1;
 671
 672         INIT_LIST_HEAD(&ilist);
 673 gc_more:
 674         if (!(sbi->sb->s_flags & MS_ACTIVE))
 675                 goto stop;
 676
 677         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
 678                 gc_type = FG_GC;
 679                 write_checkpoint(sbi, false);
 680         }
 681
 682         if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
 683                 goto stop;
 684         ret = 0;
 685
 686         for (i = 0; i < sbi->segs_per_sec; i++)
 687                 do_garbage_collect(sbi, segno + i, &ilist, gc_type);
 688
 689         if (gc_type == FG_GC) {
 690                 sbi->cur_victim_sec = NULL_SEGNO;
 691                 nfree++;
 692                 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
 693         }
 694
 695         if (has_not_enough_free_secs(sbi, nfree))
 696                 goto gc_more;
 697
 698         if (gc_type == FG_GC)
 699                 write_checkpoint(sbi, false);
 700 stop:
 701         mutex_unlock(&sbi->gc_mutex);
 702
 703         put_gc_inode(&ilist);
 704         return ret;
 705 }
 706
 707 void build_gc_manager(struct f2fs_sb_info *sbi)
 708 {
 709         DIRTY_I(sbi)->v_ops = &default_v_ops;
 710 }
 711
 712 int __init create_gc_caches(void)
 713 {
 714         winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
 715                         sizeof(struct inode_entry), NULL);
 716         if (!winode_slab)
 717                 return -ENOMEM;
 718         return 0;
 719 }
 720
 721 void destroy_gc_caches(void)
 722 {
 723         kmem_cache_destroy(winode_slab);
 724 }