Pileus Git - ~andy/linux/blob - 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         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
  33         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
  34         long wait_ms;
  35
  36         wait_ms = gc_th->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 = increase_sleep_time(gc_th, wait_ms);
  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(gc_th, 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(gc_th, wait_ms);
  77                 else
  78                         wait_ms = increase_sleep_time(gc_th, wait_ms);
  79
  80                 stat_inc_bggc_count(sbi);
  81
  82                 /* if return value is not zero, no victim was selected */
  83                 if (f2fs_gc(sbi))
  84                         wait_ms = gc_th->no_gc_sleep_time;
  85
  86                 /* balancing f2fs's metadata periodically */
  87                 f2fs_balance_fs_bg(sbi);
  88
  89         } while (!kthread_should_stop());
  90         return 0;
  91 }
  92
  93 int start_gc_thread(struct f2fs_sb_info *sbi)
  94 {
  95         struct f2fs_gc_kthread *gc_th;
  96         dev_t dev = sbi->sb->s_bdev->bd_dev;
  97         int err = 0;
  98
  99         if (!test_opt(sbi, BG_GC))
 100                 goto out;
 101         gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
 102         if (!gc_th) {
 103                 err = -ENOMEM;
 104                 goto out;
 105         }
 106
 107         gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
 108         gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
 109         gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
 110
 111         gc_th->gc_idle = 0;
 112
 113         sbi->gc_thread = gc_th;
 114         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 115         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 116                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 117         if (IS_ERR(gc_th->f2fs_gc_task)) {
 118                 err = PTR_ERR(gc_th->f2fs_gc_task);
 119                 kfree(gc_th);
 120                 sbi->gc_thread = NULL;
 121         }
 122
 123 out:
 124         return err;
 125 }
 126
 127 void stop_gc_thread(struct f2fs_sb_info *sbi)
 128 {
 129         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 130         if (!gc_th)
 131                 return;
 132         kthread_stop(gc_th->f2fs_gc_task);
 133         kfree(gc_th);
 134         sbi->gc_thread = NULL;
 135 }
 136
 137 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
 138 {
 139         int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 140
 141         if (gc_th && gc_th->gc_idle) {
 142                 if (gc_th->gc_idle == 1)
 143                         gc_mode = GC_CB;
 144                 else if (gc_th->gc_idle == 2)
 145                         gc_mode = GC_GREEDY;
 146         }
 147         return gc_mode;
 148 }
 149
 150 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 151                         int type, struct victim_sel_policy *p)
 152 {
 153         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 154
 155         if (p->alloc_mode == SSR) {
 156                 p->gc_mode = GC_GREEDY;
 157                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 158                 p->max_search = dirty_i->nr_dirty[type];
 159                 p->ofs_unit = 1;
 160         } else {
 161                 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
 162                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 163                 p->max_search = dirty_i->nr_dirty[DIRTY];
 164                 p->ofs_unit = sbi->segs_per_sec;
 165         }
 166
 167         if (p->max_search > MAX_VICTIM_SEARCH)
 168                 p->max_search = MAX_VICTIM_SEARCH;
 169
 170         p->offset = sbi->last_victim[p->gc_mode];
 171 }
 172
 173 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 174                                 struct victim_sel_policy *p)
 175 {
 176         /* SSR allocates in a segment unit */
 177         if (p->alloc_mode == SSR)
 178                 return 1 << sbi->log_blocks_per_seg;
 179         if (p->gc_mode == GC_GREEDY)
 180                 return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
 181         else if (p->gc_mode == GC_CB)
 182                 return UINT_MAX;
 183         else /* No other gc_mode */
 184                 return 0;
 185 }
 186
 187 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 188 {
 189         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 190         unsigned int hint = 0;
 191         unsigned int secno;
 192
 193         /*
 194          * If the gc_type is FG_GC, we can select victim segments
 195          * selected by background GC before.
 196          * Those segments guarantee they have small valid blocks.
 197          */
 198 next:
 199         secno = find_next_bit(dirty_i->victim_secmap, TOTAL_SECS(sbi), hint++);
 200         if (secno < TOTAL_SECS(sbi)) {
 201                 if (sec_usage_check(sbi, secno))
 202                         goto next;
 203                 clear_bit(secno, dirty_i->victim_secmap);
 204                 return secno * sbi->segs_per_sec;
 205         }
 206         return NULL_SEGNO;
 207 }
 208
 209 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 210 {
 211         struct sit_info *sit_i = SIT_I(sbi);
 212         unsigned int secno = GET_SECNO(sbi, segno);
 213         unsigned int start = secno * sbi->segs_per_sec;
 214         unsigned long long mtime = 0;
 215         unsigned int vblocks;
 216         unsigned char age = 0;
 217         unsigned char u;
 218         unsigned int i;
 219
 220         for (i = 0; i < sbi->segs_per_sec; i++)
 221                 mtime += get_seg_entry(sbi, start + i)->mtime;
 222         vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 223
 224         mtime = div_u64(mtime, sbi->segs_per_sec);
 225         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 226
 227         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 228
 229         /* Handle if the system time is changed by user */
 230         if (mtime < sit_i->min_mtime)
 231                 sit_i->min_mtime = mtime;
 232         if (mtime > sit_i->max_mtime)
 233                 sit_i->max_mtime = mtime;
 234         if (sit_i->max_mtime != sit_i->min_mtime)
 235                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 236                                 sit_i->max_mtime - sit_i->min_mtime);
 237
 238         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 239 }
 240
 241 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 242                         unsigned int segno, struct victim_sel_policy *p)
 243 {
 244         if (p->alloc_mode == SSR)
 245                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 246
 247         /* alloc_mode == LFS */
 248         if (p->gc_mode == GC_GREEDY)
 249                 return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 250         else
 251                 return get_cb_cost(sbi, segno);
 252 }
 253
 254 /*
 255  * This function is called from two paths.
 256  * One is garbage collection and the other is SSR segment selection.
 257  * When it is called during GC, it just gets a victim segment
 258  * and it does not remove it from dirty seglist.
 259  * When it is called from SSR segment selection, it finds a segment
 260  * which has minimum valid blocks and removes it from dirty seglist.
 261  */
 262 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 263                 unsigned int *result, int gc_type, int type, char alloc_mode)
 264 {
 265         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 266         struct victim_sel_policy p;
 267         unsigned int secno, max_cost;
 268         int nsearched = 0;
 269
 270         p.alloc_mode = alloc_mode;
 271         select_policy(sbi, gc_type, type, &p);
 272
 273         p.min_segno = NULL_SEGNO;
 274         p.min_cost = max_cost = get_max_cost(sbi, &p);
 275
 276         mutex_lock(&dirty_i->seglist_lock);
 277
 278         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 279                 p.min_segno = check_bg_victims(sbi);
 280                 if (p.min_segno != NULL_SEGNO)
 281                         goto got_it;
 282         }
 283
 284         while (1) {
 285                 unsigned long cost;
 286                 unsigned int segno;
 287
 288                 segno = find_next_bit(p.dirty_segmap,
 289                                                 TOTAL_SEGS(sbi), p.offset);
 290                 if (segno >= TOTAL_SEGS(sbi)) {
 291                         if (sbi->last_victim[p.gc_mode]) {
 292                                 sbi->last_victim[p.gc_mode] = 0;
 293                                 p.offset = 0;
 294                                 continue;
 295                         }
 296                         break;
 297                 }
 298
 299                 p.offset = segno + p.ofs_unit;
 300                 if (p.ofs_unit > 1)
 301                         p.offset -= segno % p.ofs_unit;
 302
 303                 secno = GET_SECNO(sbi, segno);
 304
 305                 if (sec_usage_check(sbi, secno))
 306                         continue;
 307                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 308                         continue;
 309
 310                 cost = get_gc_cost(sbi, segno, &p);
 311
 312                 if (p.min_cost > cost) {
 313                         p.min_segno = segno;
 314                         p.min_cost = cost;
 315                 } else if (unlikely(cost == max_cost)) {
 316                         continue;
 317                 }
 318
 319                 if (nsearched++ >= p.max_search) {
 320                         sbi->last_victim[p.gc_mode] = segno;
 321                         break;
 322                 }
 323         }
 324         if (p.min_segno != NULL_SEGNO) {
 325 got_it:
 326                 if (p.alloc_mode == LFS) {
 327                         secno = GET_SECNO(sbi, p.min_segno);
 328                         if (gc_type == FG_GC)
 329                                 sbi->cur_victim_sec = secno;
 330                         else
 331                                 set_bit(secno, dirty_i->victim_secmap);
 332                 }
 333                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 334
 335                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 336                                 sbi->cur_victim_sec,
 337                                 prefree_segments(sbi), free_segments(sbi));
 338         }
 339         mutex_unlock(&dirty_i->seglist_lock);
 340
 341         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 342 }
 343
 344 static const struct victim_selection default_v_ops = {
 345         .get_victim = get_victim_by_default,
 346 };
 347
 348 static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
 349 {
 350         struct inode_entry *ie;
 351
 352         list_for_each_entry(ie, ilist, list)
 353                 if (ie->inode->i_ino == ino)
 354                         return ie->inode;
 355         return NULL;
 356 }
 357
 358 static void add_gc_inode(struct inode *inode, struct list_head *ilist)
 359 {
 360         struct inode_entry *new_ie;
 361
 362         if (inode == find_gc_inode(inode->i_ino, ilist)) {
 363                 iput(inode);
 364                 return;
 365         }
 366
 367         new_ie = f2fs_kmem_cache_alloc(winode_slab, GFP_NOFS);
 368         new_ie->inode = inode;
 369         list_add_tail(&new_ie->list, ilist);
 370 }
 371
 372 static void put_gc_inode(struct list_head *ilist)
 373 {
 374         struct inode_entry *ie, *next_ie;
 375         list_for_each_entry_safe(ie, next_ie, ilist, list) {
 376                 iput(ie->inode);
 377                 list_del(&ie->list);
 378                 kmem_cache_free(winode_slab, ie);
 379         }
 380 }
 381
 382 static int check_valid_map(struct f2fs_sb_info *sbi,
 383                                 unsigned int segno, int offset)
 384 {
 385         struct sit_info *sit_i = SIT_I(sbi);
 386         struct seg_entry *sentry;
 387         int ret;
 388
 389         mutex_lock(&sit_i->sentry_lock);
 390         sentry = get_seg_entry(sbi, segno);
 391         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 392         mutex_unlock(&sit_i->sentry_lock);
 393         return ret;
 394 }
 395
 396 /*
 397  * This function compares node address got in summary with that in NAT.
 398  * On validity, copy that node with cold status, otherwise (invalid node)
 399  * ignore that.
 400  */
 401 static void gc_node_segment(struct f2fs_sb_info *sbi,
 402                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 403 {
 404         bool initial = true;
 405         struct f2fs_summary *entry;
 406         int off;
 407
 408 next_step:
 409         entry = sum;
 410
 411         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 412                 nid_t nid = le32_to_cpu(entry->nid);
 413                 struct page *node_page;
 414
 415                 /* stop BG_GC if there is not enough free sections. */
 416                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 417                         return;
 418
 419                 if (check_valid_map(sbi, segno, off) == 0)
 420                         continue;
 421
 422                 if (initial) {
 423                         ra_node_page(sbi, nid);
 424                         continue;
 425                 }
 426                 node_page = get_node_page(sbi, nid);
 427                 if (IS_ERR(node_page))
 428                         continue;
 429
 430                 /* set page dirty and write it */
 431                 if (gc_type == FG_GC) {
 432                         f2fs_wait_on_page_writeback(node_page, NODE, true);
 433                         set_page_dirty(node_page);
 434                 } else {
 435                         if (!PageWriteback(node_page))
 436                                 set_page_dirty(node_page);
 437                 }
 438                 f2fs_put_page(node_page, 1);
 439                 stat_inc_node_blk_count(sbi, 1);
 440         }
 441
 442         if (initial) {
 443                 initial = false;
 444                 goto next_step;
 445         }
 446
 447         if (gc_type == FG_GC) {
 448                 struct writeback_control wbc = {
 449                         .sync_mode = WB_SYNC_ALL,
 450                         .nr_to_write = LONG_MAX,
 451                         .for_reclaim = 0,
 452                 };
 453                 sync_node_pages(sbi, 0, &wbc);
 454
 455                 /*
 456                  * In the case of FG_GC, it'd be better to reclaim this victim
 457                  * completely.
 458                  */
 459                 if (get_valid_blocks(sbi, segno, 1) != 0)
 460                         goto next_step;
 461         }
 462 }
 463
 464 /*
 465  * Calculate start block index indicating the given node offset.
 466  * Be careful, caller should give this node offset only indicating direct node
 467  * blocks. If any node offsets, which point the other types of node blocks such
 468  * as indirect or double indirect node blocks, are given, it must be a caller's
 469  * bug.
 470  */
 471 block_t start_bidx_of_node(unsigned int node_ofs, struct f2fs_inode_info *fi)
 472 {
 473         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 474         unsigned int bidx;
 475
 476         if (node_ofs == 0)
 477                 return 0;
 478
 479         if (node_ofs <= 2) {
 480                 bidx = node_ofs - 1;
 481         } else if (node_ofs <= indirect_blks) {
 482                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 483                 bidx = node_ofs - 2 - dec;
 484         } else {
 485                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 486                 bidx = node_ofs - 5 - dec;
 487         }
 488         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi);
 489 }
 490
 491 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 492                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 493 {
 494         struct page *node_page;
 495         nid_t nid;
 496         unsigned int ofs_in_node;
 497         block_t source_blkaddr;
 498
 499         nid = le32_to_cpu(sum->nid);
 500         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 501
 502         node_page = get_node_page(sbi, nid);
 503         if (IS_ERR(node_page))
 504                 return 0;
 505
 506         get_node_info(sbi, nid, dni);
 507
 508         if (sum->version != dni->version) {
 509                 f2fs_put_page(node_page, 1);
 510                 return 0;
 511         }
 512
 513         *nofs = ofs_of_node(node_page);
 514         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 515         f2fs_put_page(node_page, 1);
 516
 517         if (source_blkaddr != blkaddr)
 518                 return 0;
 519         return 1;
 520 }
 521
 522 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
 523 {
 524         if (gc_type == BG_GC) {
 525                 if (PageWriteback(page))
 526                         goto out;
 527                 set_page_dirty(page);
 528                 set_cold_data(page);
 529         } else {
 530                 struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 531
 532                 f2fs_wait_on_page_writeback(page, DATA, true);
 533
 534                 if (clear_page_dirty_for_io(page) &&
 535                         S_ISDIR(inode->i_mode)) {
 536                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 537                         inode_dec_dirty_dents(inode);
 538                 }
 539                 set_cold_data(page);
 540                 do_write_data_page(page);
 541                 clear_cold_data(page);
 542         }
 543 out:
 544         f2fs_put_page(page, 1);
 545 }
 546
 547 /*
 548  * This function tries to get parent node of victim data block, and identifies
 549  * data block validity. If the block is valid, copy that with cold status and
 550  * modify parent node.
 551  * If the parent node is not valid or the data block address is different,
 552  * the victim data block is ignored.
 553  */
 554 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 555                 struct list_head *ilist, unsigned int segno, int gc_type)
 556 {
 557         struct super_block *sb = sbi->sb;
 558         struct f2fs_summary *entry;
 559         block_t start_addr;
 560         int off;
 561         int phase = 0;
 562
 563         start_addr = START_BLOCK(sbi, segno);
 564
 565 next_step:
 566         entry = sum;
 567
 568         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 569                 struct page *data_page;
 570                 struct inode *inode;
 571                 struct node_info dni; /* dnode info for the data */
 572                 unsigned int ofs_in_node, nofs;
 573                 block_t start_bidx;
 574
 575                 /* stop BG_GC if there is not enough free sections. */
 576                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 577                         return;
 578
 579                 if (check_valid_map(sbi, segno, off) == 0)
 580                         continue;
 581
 582                 if (phase == 0) {
 583                         ra_node_page(sbi, le32_to_cpu(entry->nid));
 584                         continue;
 585                 }
 586
 587                 /* Get an inode by ino with checking validity */
 588                 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
 589                         continue;
 590
 591                 if (phase == 1) {
 592                         ra_node_page(sbi, dni.ino);
 593                         continue;
 594                 }
 595
 596                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 597
 598                 if (phase == 2) {
 599                         inode = f2fs_iget(sb, dni.ino);
 600                         if (IS_ERR(inode))
 601                                 continue;
 602
 603                         start_bidx = start_bidx_of_node(nofs, F2FS_I(inode));
 604
 605                         data_page = find_data_page(inode,
 606                                         start_bidx + ofs_in_node, false);
 607                         if (IS_ERR(data_page))
 608                                 goto next_iput;
 609
 610                         f2fs_put_page(data_page, 0);
 611                         add_gc_inode(inode, ilist);
 612                 } else {
 613                         inode = find_gc_inode(dni.ino, ilist);
 614                         if (inode) {
 615                                 start_bidx = start_bidx_of_node(nofs,
 616                                                                 F2FS_I(inode));
 617                                 data_page = get_lock_data_page(inode,
 618                                                 start_bidx + ofs_in_node);
 619                                 if (IS_ERR(data_page))
 620                                         continue;
 621                                 move_data_page(inode, data_page, gc_type);
 622                                 stat_inc_data_blk_count(sbi, 1);
 623                         }
 624                 }
 625                 continue;
 626 next_iput:
 627                 iput(inode);
 628         }
 629
 630         if (++phase < 4)
 631                 goto next_step;
 632
 633         if (gc_type == FG_GC) {
 634                 f2fs_submit_bio(sbi, DATA, true);
 635
 636                 /*
 637                  * In the case of FG_GC, it'd be better to reclaim this victim
 638                  * completely.
 639                  */
 640                 if (get_valid_blocks(sbi, segno, 1) != 0) {
 641                         phase = 2;
 642                         goto next_step;
 643                 }
 644         }
 645 }
 646
 647 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 648                                                 int gc_type, int type)
 649 {
 650         struct sit_info *sit_i = SIT_I(sbi);
 651         int ret;
 652         mutex_lock(&sit_i->sentry_lock);
 653         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
 654         mutex_unlock(&sit_i->sentry_lock);
 655         return ret;
 656 }
 657
 658 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
 659                                 struct list_head *ilist, int gc_type)
 660 {
 661         struct page *sum_page;
 662         struct f2fs_summary_block *sum;
 663         struct blk_plug plug;
 664
 665         /* read segment summary of victim */
 666         sum_page = get_sum_page(sbi, segno);
 667         if (IS_ERR(sum_page))
 668                 return;
 669
 670         blk_start_plug(&plug);
 671
 672         sum = page_address(sum_page);
 673
 674         switch (GET_SUM_TYPE((&sum->footer))) {
 675         case SUM_TYPE_NODE:
 676                 gc_node_segment(sbi, sum->entries, segno, gc_type);
 677                 break;
 678         case SUM_TYPE_DATA:
 679                 gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
 680                 break;
 681         }
 682         blk_finish_plug(&plug);
 683
 684         stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
 685         stat_inc_call_count(sbi->stat_info);
 686
 687         f2fs_put_page(sum_page, 1);
 688 }
 689
 690 int f2fs_gc(struct f2fs_sb_info *sbi)
 691 {
 692         struct list_head ilist;
 693         unsigned int segno, i;
 694         int gc_type = BG_GC;
 695         int nfree = 0;
 696         int ret = -1;
 697
 698         INIT_LIST_HEAD(&ilist);
 699 gc_more:
 700         if (!(sbi->sb->s_flags & MS_ACTIVE))
 701                 goto stop;
 702
 703         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
 704                 gc_type = FG_GC;
 705                 write_checkpoint(sbi, false);
 706         }
 707
 708         if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
 709                 goto stop;
 710         ret = 0;
 711
 712         for (i = 0; i < sbi->segs_per_sec; i++)
 713                 do_garbage_collect(sbi, segno + i, &ilist, gc_type);
 714
 715         if (gc_type == FG_GC) {
 716                 sbi->cur_victim_sec = NULL_SEGNO;
 717                 nfree++;
 718                 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
 719         }
 720
 721         if (has_not_enough_free_secs(sbi, nfree))
 722                 goto gc_more;
 723
 724         if (gc_type == FG_GC)
 725                 write_checkpoint(sbi, false);
 726 stop:
 727         mutex_unlock(&sbi->gc_mutex);
 728
 729         put_gc_inode(&ilist);
 730         return ret;
 731 }
 732
 733 void build_gc_manager(struct f2fs_sb_info *sbi)
 734 {
 735         DIRTY_I(sbi)->v_ops = &default_v_ops;
 736 }
 737
 738 int __init create_gc_caches(void)
 739 {
 740         winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
 741                         sizeof(struct inode_entry), NULL);
 742         if (!winode_slab)
 743                 return -ENOMEM;
 744         return 0;
 745 }
 746
 747 void destroy_gc_caches(void)
 748 {
 749         kmem_cache_destroy(winode_slab);
 750 }