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