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