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 #ifdef CONFIG_F2FS_STAT_FS
  81                 sbi->bg_gc++;
  82 #endif
  83
  84                 /* if return value is not zero, no victim was selected */
  85                 if (f2fs_gc(sbi))
  86                         wait_ms = gc_th->no_gc_sleep_time;
  87         } while (!kthread_should_stop());
  88         return 0;
  89 }
  90
  91 int start_gc_thread(struct f2fs_sb_info *sbi)
  92 {
  93         struct f2fs_gc_kthread *gc_th;
  94         dev_t dev = sbi->sb->s_bdev->bd_dev;
  95         int err = 0;
  96
  97         if (!test_opt(sbi, BG_GC))
  98                 goto out;
  99         gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
 100         if (!gc_th) {
 101                 err = -ENOMEM;
 102                 goto out;
 103         }
 104
 105         gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
 106         gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
 107         gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
 108
 109         sbi->gc_thread = gc_th;
 110         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 111         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 112                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 113         if (IS_ERR(gc_th->f2fs_gc_task)) {
 114                 err = PTR_ERR(gc_th->f2fs_gc_task);
 115                 kfree(gc_th);
 116                 sbi->gc_thread = NULL;
 117         }
 118
 119 out:
 120         return err;
 121 }
 122
 123 void stop_gc_thread(struct f2fs_sb_info *sbi)
 124 {
 125         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 126         if (!gc_th)
 127                 return;
 128         kthread_stop(gc_th->f2fs_gc_task);
 129         kfree(gc_th);
 130         sbi->gc_thread = NULL;
 131 }
 132
 133 static int select_gc_type(int gc_type)
 134 {
 135         return (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 136 }
 137
 138 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 139                         int type, struct victim_sel_policy *p)
 140 {
 141         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 142
 143         if (p->alloc_mode == SSR) {
 144                 p->gc_mode = GC_GREEDY;
 145                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 146                 p->ofs_unit = 1;
 147         } else {
 148                 p->gc_mode = select_gc_type(gc_type);
 149                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 150                 p->ofs_unit = sbi->segs_per_sec;
 151         }
 152         p->offset = sbi->last_victim[p->gc_mode];
 153 }
 154
 155 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 156                                 struct victim_sel_policy *p)
 157 {
 158         /* SSR allocates in a segment unit */
 159         if (p->alloc_mode == SSR)
 160                 return 1 << sbi->log_blocks_per_seg;
 161         if (p->gc_mode == GC_GREEDY)
 162                 return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
 163         else if (p->gc_mode == GC_CB)
 164                 return UINT_MAX;
 165         else /* No other gc_mode */
 166                 return 0;
 167 }
 168
 169 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 170 {
 171         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 172         unsigned int hint = 0;
 173         unsigned int secno;
 174
 175         /*
 176          * If the gc_type is FG_GC, we can select victim segments
 177          * selected by background GC before.
 178          * Those segments guarantee they have small valid blocks.
 179          */
 180 next:
 181         secno = find_next_bit(dirty_i->victim_secmap, TOTAL_SECS(sbi), hint++);
 182         if (secno < TOTAL_SECS(sbi)) {
 183                 if (sec_usage_check(sbi, secno))
 184                         goto next;
 185                 clear_bit(secno, dirty_i->victim_secmap);
 186                 return secno * sbi->segs_per_sec;
 187         }
 188         return NULL_SEGNO;
 189 }
 190
 191 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 192 {
 193         struct sit_info *sit_i = SIT_I(sbi);
 194         unsigned int secno = GET_SECNO(sbi, segno);
 195         unsigned int start = secno * sbi->segs_per_sec;
 196         unsigned long long mtime = 0;
 197         unsigned int vblocks;
 198         unsigned char age = 0;
 199         unsigned char u;
 200         unsigned int i;
 201
 202         for (i = 0; i < sbi->segs_per_sec; i++)
 203                 mtime += get_seg_entry(sbi, start + i)->mtime;
 204         vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 205
 206         mtime = div_u64(mtime, sbi->segs_per_sec);
 207         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 208
 209         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 210
 211         /* Handle if the system time is changed by user */
 212         if (mtime < sit_i->min_mtime)
 213                 sit_i->min_mtime = mtime;
 214         if (mtime > sit_i->max_mtime)
 215                 sit_i->max_mtime = mtime;
 216         if (sit_i->max_mtime != sit_i->min_mtime)
 217                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 218                                 sit_i->max_mtime - sit_i->min_mtime);
 219
 220         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 221 }
 222
 223 static unsigned int get_gc_cost(struct f2fs_sb_info *sbi, unsigned int segno,
 224                                         struct victim_sel_policy *p)
 225 {
 226         if (p->alloc_mode == SSR)
 227                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 228
 229         /* alloc_mode == LFS */
 230         if (p->gc_mode == GC_GREEDY)
 231                 return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 232         else
 233                 return get_cb_cost(sbi, segno);
 234 }
 235
 236 /*
 237  * This function is called from two paths.
 238  * One is garbage collection and the other is SSR segment selection.
 239  * When it is called during GC, it just gets a victim segment
 240  * and it does not remove it from dirty seglist.
 241  * When it is called from SSR segment selection, it finds a segment
 242  * which has minimum valid blocks and removes it from dirty seglist.
 243  */
 244 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 245                 unsigned int *result, int gc_type, int type, char alloc_mode)
 246 {
 247         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 248         struct victim_sel_policy p;
 249         unsigned int secno, max_cost;
 250         int nsearched = 0;
 251
 252         p.alloc_mode = alloc_mode;
 253         select_policy(sbi, gc_type, type, &p);
 254
 255         p.min_segno = NULL_SEGNO;
 256         p.min_cost = max_cost = get_max_cost(sbi, &p);
 257
 258         mutex_lock(&dirty_i->seglist_lock);
 259
 260         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 261                 p.min_segno = check_bg_victims(sbi);
 262                 if (p.min_segno != NULL_SEGNO)
 263                         goto got_it;
 264         }
 265
 266         while (1) {
 267                 unsigned long cost;
 268                 unsigned int segno;
 269
 270                 segno = find_next_bit(p.dirty_segmap,
 271                                                 TOTAL_SEGS(sbi), p.offset);
 272                 if (segno >= TOTAL_SEGS(sbi)) {
 273                         if (sbi->last_victim[p.gc_mode]) {
 274                                 sbi->last_victim[p.gc_mode] = 0;
 275                                 p.offset = 0;
 276                                 continue;
 277                         }
 278                         break;
 279                 }
 280                 p.offset = ((segno / p.ofs_unit) * p.ofs_unit) + p.ofs_unit;
 281                 secno = GET_SECNO(sbi, segno);
 282
 283                 if (sec_usage_check(sbi, secno))
 284                         continue;
 285                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 286                         continue;
 287
 288                 cost = get_gc_cost(sbi, segno, &p);
 289
 290                 if (p.min_cost > cost) {
 291                         p.min_segno = segno;
 292                         p.min_cost = cost;
 293                 }
 294
 295                 if (cost == max_cost)
 296                         continue;
 297
 298                 if (nsearched++ >= MAX_VICTIM_SEARCH) {
 299                         sbi->last_victim[p.gc_mode] = segno;
 300                         break;
 301                 }
 302         }
 303         if (p.min_segno != NULL_SEGNO) {
 304 got_it:
 305                 if (p.alloc_mode == LFS) {
 306                         secno = GET_SECNO(sbi, p.min_segno);
 307                         if (gc_type == FG_GC)
 308                                 sbi->cur_victim_sec = secno;
 309                         else
 310                                 set_bit(secno, dirty_i->victim_secmap);
 311                 }
 312                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 313
 314                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 315                                 sbi->cur_victim_sec,
 316                                 prefree_segments(sbi), free_segments(sbi));
 317         }
 318         mutex_unlock(&dirty_i->seglist_lock);
 319
 320         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 321 }
 322
 323 static const struct victim_selection default_v_ops = {
 324         .get_victim = get_victim_by_default,
 325 };
 326
 327 static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
 328 {
 329         struct inode_entry *ie;
 330
 331         list_for_each_entry(ie, ilist, list)
 332                 if (ie->inode->i_ino == ino)
 333                         return ie->inode;
 334         return NULL;
 335 }
 336
 337 static void add_gc_inode(struct inode *inode, struct list_head *ilist)
 338 {
 339         struct inode_entry *new_ie;
 340
 341         if (inode == find_gc_inode(inode->i_ino, ilist)) {
 342                 iput(inode);
 343                 return;
 344         }
 345 repeat:
 346         new_ie = kmem_cache_alloc(winode_slab, GFP_NOFS);
 347         if (!new_ie) {
 348                 cond_resched();
 349                 goto repeat;
 350         }
 351         new_ie->inode = inode;
 352         list_add_tail(&new_ie->list, ilist);
 353 }
 354
 355 static void put_gc_inode(struct list_head *ilist)
 356 {
 357         struct inode_entry *ie, *next_ie;
 358         list_for_each_entry_safe(ie, next_ie, ilist, list) {
 359                 iput(ie->inode);
 360                 list_del(&ie->list);
 361                 kmem_cache_free(winode_slab, ie);
 362         }
 363 }
 364
 365 static int check_valid_map(struct f2fs_sb_info *sbi,
 366                                 unsigned int segno, int offset)
 367 {
 368         struct sit_info *sit_i = SIT_I(sbi);
 369         struct seg_entry *sentry;
 370         int ret;
 371
 372         mutex_lock(&sit_i->sentry_lock);
 373         sentry = get_seg_entry(sbi, segno);
 374         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 375         mutex_unlock(&sit_i->sentry_lock);
 376         return ret;
 377 }
 378
 379 /*
 380  * This function compares node address got in summary with that in NAT.
 381  * On validity, copy that node with cold status, otherwise (invalid node)
 382  * ignore that.
 383  */
 384 static void gc_node_segment(struct f2fs_sb_info *sbi,
 385                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 386 {
 387         bool initial = true;
 388         struct f2fs_summary *entry;
 389         int off;
 390
 391 next_step:
 392         entry = sum;
 393
 394         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 395                 nid_t nid = le32_to_cpu(entry->nid);
 396                 struct page *node_page;
 397
 398                 /* stop BG_GC if there is not enough free sections. */
 399                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 400                         return;
 401
 402                 if (check_valid_map(sbi, segno, off) == 0)
 403                         continue;
 404
 405                 if (initial) {
 406                         ra_node_page(sbi, nid);
 407                         continue;
 408                 }
 409                 node_page = get_node_page(sbi, nid);
 410                 if (IS_ERR(node_page))
 411                         continue;
 412
 413                 /* set page dirty and write it */
 414                 if (gc_type == FG_GC) {
 415                         f2fs_submit_bio(sbi, NODE, true);
 416                         wait_on_page_writeback(node_page);
 417                         set_page_dirty(node_page);
 418                 } else {
 419                         if (!PageWriteback(node_page))
 420                                 set_page_dirty(node_page);
 421                 }
 422                 f2fs_put_page(node_page, 1);
 423                 stat_inc_node_blk_count(sbi, 1);
 424         }
 425
 426         if (initial) {
 427                 initial = false;
 428                 goto next_step;
 429         }
 430
 431         if (gc_type == FG_GC) {
 432                 struct writeback_control wbc = {
 433                         .sync_mode = WB_SYNC_ALL,
 434                         .nr_to_write = LONG_MAX,
 435                         .for_reclaim = 0,
 436                 };
 437                 sync_node_pages(sbi, 0, &wbc);
 438
 439                 /*
 440                  * In the case of FG_GC, it'd be better to reclaim this victim
 441                  * completely.
 442                  */
 443                 if (get_valid_blocks(sbi, segno, 1) != 0)
 444                         goto next_step;
 445         }
 446 }
 447
 448 /*
 449  * Calculate start block index indicating the given node offset.
 450  * Be careful, caller should give this node offset only indicating direct node
 451  * blocks. If any node offsets, which point the other types of node blocks such
 452  * as indirect or double indirect node blocks, are given, it must be a caller's
 453  * bug.
 454  */
 455 block_t start_bidx_of_node(unsigned int node_ofs)
 456 {
 457         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 458         unsigned int bidx;
 459
 460         if (node_ofs == 0)
 461                 return 0;
 462
 463         if (node_ofs <= 2) {
 464                 bidx = node_ofs - 1;
 465         } else if (node_ofs <= indirect_blks) {
 466                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 467                 bidx = node_ofs - 2 - dec;
 468         } else {
 469                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 470                 bidx = node_ofs - 5 - dec;
 471         }
 472         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE;
 473 }
 474
 475 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 476                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 477 {
 478         struct page *node_page;
 479         nid_t nid;
 480         unsigned int ofs_in_node;
 481         block_t source_blkaddr;
 482
 483         nid = le32_to_cpu(sum->nid);
 484         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 485
 486         node_page = get_node_page(sbi, nid);
 487         if (IS_ERR(node_page))
 488                 return 0;
 489
 490         get_node_info(sbi, nid, dni);
 491
 492         if (sum->version != dni->version) {
 493                 f2fs_put_page(node_page, 1);
 494                 return 0;
 495         }
 496
 497         *nofs = ofs_of_node(node_page);
 498         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 499         f2fs_put_page(node_page, 1);
 500
 501         if (source_blkaddr != blkaddr)
 502                 return 0;
 503         return 1;
 504 }
 505
 506 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
 507 {
 508         if (gc_type == BG_GC) {
 509                 if (PageWriteback(page))
 510                         goto out;
 511                 set_page_dirty(page);
 512                 set_cold_data(page);
 513         } else {
 514                 struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 515
 516                 if (PageWriteback(page)) {
 517                         f2fs_submit_bio(sbi, DATA, true);
 518                         wait_on_page_writeback(page);
 519                 }
 520
 521                 if (clear_page_dirty_for_io(page) &&
 522                         S_ISDIR(inode->i_mode)) {
 523                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 524                         inode_dec_dirty_dents(inode);
 525                 }
 526                 set_cold_data(page);
 527                 do_write_data_page(page);
 528                 clear_cold_data(page);
 529         }
 530 out:
 531         f2fs_put_page(page, 1);
 532 }
 533
 534 /*
 535  * This function tries to get parent node of victim data block, and identifies
 536  * data block validity. If the block is valid, copy that with cold status and
 537  * modify parent node.
 538  * If the parent node is not valid or the data block address is different,
 539  * the victim data block is ignored.
 540  */
 541 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 542                 struct list_head *ilist, unsigned int segno, int gc_type)
 543 {
 544         struct super_block *sb = sbi->sb;
 545         struct f2fs_summary *entry;
 546         block_t start_addr;
 547         int off;
 548         int phase = 0;
 549
 550         start_addr = START_BLOCK(sbi, segno);
 551
 552 next_step:
 553         entry = sum;
 554
 555         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 556                 struct page *data_page;
 557                 struct inode *inode;
 558                 struct node_info dni; /* dnode info for the data */
 559                 unsigned int ofs_in_node, nofs;
 560                 block_t start_bidx;
 561
 562                 /* stop BG_GC if there is not enough free sections. */
 563                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 564                         return;
 565
 566                 if (check_valid_map(sbi, segno, off) == 0)
 567                         continue;
 568
 569                 if (phase == 0) {
 570                         ra_node_page(sbi, le32_to_cpu(entry->nid));
 571                         continue;
 572                 }
 573
 574                 /* Get an inode by ino with checking validity */
 575                 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
 576                         continue;
 577
 578                 if (phase == 1) {
 579                         ra_node_page(sbi, dni.ino);
 580                         continue;
 581                 }
 582
 583                 start_bidx = start_bidx_of_node(nofs);
 584                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 585
 586                 if (phase == 2) {
 587                         inode = f2fs_iget(sb, dni.ino);
 588                         if (IS_ERR(inode))
 589                                 continue;
 590
 591                         data_page = find_data_page(inode,
 592                                         start_bidx + ofs_in_node, false);
 593                         if (IS_ERR(data_page))
 594                                 goto next_iput;
 595
 596                         f2fs_put_page(data_page, 0);
 597                         add_gc_inode(inode, ilist);
 598                 } else {
 599                         inode = find_gc_inode(dni.ino, ilist);
 600                         if (inode) {
 601                                 data_page = get_lock_data_page(inode,
 602                                                 start_bidx + ofs_in_node);
 603                                 if (IS_ERR(data_page))
 604                                         continue;
 605                                 move_data_page(inode, data_page, gc_type);
 606                                 stat_inc_data_blk_count(sbi, 1);
 607                         }
 608                 }
 609                 continue;
 610 next_iput:
 611                 iput(inode);
 612         }
 613
 614         if (++phase < 4)
 615                 goto next_step;
 616
 617         if (gc_type == FG_GC) {
 618                 f2fs_submit_bio(sbi, DATA, true);
 619
 620                 /*
 621                  * In the case of FG_GC, it'd be better to reclaim this victim
 622                  * completely.
 623                  */
 624                 if (get_valid_blocks(sbi, segno, 1) != 0) {
 625                         phase = 2;
 626                         goto next_step;
 627                 }
 628         }
 629 }
 630
 631 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 632                                                 int gc_type, int type)
 633 {
 634         struct sit_info *sit_i = SIT_I(sbi);
 635         int ret;
 636         mutex_lock(&sit_i->sentry_lock);
 637         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
 638         mutex_unlock(&sit_i->sentry_lock);
 639         return ret;
 640 }
 641
 642 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
 643                                 struct list_head *ilist, int gc_type)
 644 {
 645         struct page *sum_page;
 646         struct f2fs_summary_block *sum;
 647         struct blk_plug plug;
 648
 649         /* read segment summary of victim */
 650         sum_page = get_sum_page(sbi, segno);
 651         if (IS_ERR(sum_page))
 652                 return;
 653
 654         blk_start_plug(&plug);
 655
 656         sum = page_address(sum_page);
 657
 658         switch (GET_SUM_TYPE((&sum->footer))) {
 659         case SUM_TYPE_NODE:
 660                 gc_node_segment(sbi, sum->entries, segno, gc_type);
 661                 break;
 662         case SUM_TYPE_DATA:
 663                 gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
 664                 break;
 665         }
 666         blk_finish_plug(&plug);
 667
 668         stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
 669         stat_inc_call_count(sbi->stat_info);
 670
 671         f2fs_put_page(sum_page, 1);
 672 }
 673
 674 int f2fs_gc(struct f2fs_sb_info *sbi)
 675 {
 676         struct list_head ilist;
 677         unsigned int segno, i;
 678         int gc_type = BG_GC;
 679         int nfree = 0;
 680         int ret = -1;
 681
 682         INIT_LIST_HEAD(&ilist);
 683 gc_more:
 684         if (!(sbi->sb->s_flags & MS_ACTIVE))
 685                 goto stop;
 686
 687         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
 688                 gc_type = FG_GC;
 689                 write_checkpoint(sbi, false);
 690         }
 691
 692         if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
 693                 goto stop;
 694         ret = 0;
 695
 696         for (i = 0; i < sbi->segs_per_sec; i++)
 697                 do_garbage_collect(sbi, segno + i, &ilist, gc_type);
 698
 699         if (gc_type == FG_GC) {
 700                 sbi->cur_victim_sec = NULL_SEGNO;
 701                 nfree++;
 702                 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
 703         }
 704
 705         if (has_not_enough_free_secs(sbi, nfree))
 706                 goto gc_more;
 707
 708         if (gc_type == FG_GC)
 709                 write_checkpoint(sbi, false);
 710 stop:
 711         mutex_unlock(&sbi->gc_mutex);
 712
 713         put_gc_inode(&ilist);
 714         return ret;
 715 }
 716
 717 void build_gc_manager(struct f2fs_sb_info *sbi)
 718 {
 719         DIRTY_I(sbi)->v_ops = &default_v_ops;
 720 }
 721
 722 int __init create_gc_caches(void)
 723 {
 724         winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
 725                         sizeof(struct inode_entry), NULL);
 726         if (!winode_slab)
 727                 return -ENOMEM;
 728         return 0;
 729 }
 730
 731 void destroy_gc_caches(void)
 732 {
 733         kmem_cache_destroy(winode_slab);
 734 }