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 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         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 out:
 121         return err;
 122 }
 123
 124 void stop_gc_thread(struct f2fs_sb_info *sbi)
 125 {
 126         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 127         if (!gc_th)
 128                 return;
 129         kthread_stop(gc_th->f2fs_gc_task);
 130         kfree(gc_th);
 131         sbi->gc_thread = NULL;
 132 }
 133
 134 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
 135 {
 136         int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 137
 138         if (gc_th && gc_th->gc_idle) {
 139                 if (gc_th->gc_idle == 1)
 140                         gc_mode = GC_CB;
 141                 else if (gc_th->gc_idle == 2)
 142                         gc_mode = GC_GREEDY;
 143         }
 144         return gc_mode;
 145 }
 146
 147 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 148                         int type, struct victim_sel_policy *p)
 149 {
 150         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 151
 152         if (p->alloc_mode == SSR) {
 153                 p->gc_mode = GC_GREEDY;
 154                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 155                 p->max_search = dirty_i->nr_dirty[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->max_search = dirty_i->nr_dirty[DIRTY];
 161                 p->ofs_unit = sbi->segs_per_sec;
 162         }
 163
 164         if (p->max_search > sbi->max_victim_search)
 165                 p->max_search = sbi->max_victim_search;
 166
 167         p->offset = sbi->last_victim[p->gc_mode];
 168 }
 169
 170 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 171                                 struct victim_sel_policy *p)
 172 {
 173         /* SSR allocates in a segment unit */
 174         if (p->alloc_mode == SSR)
 175                 return 1 << sbi->log_blocks_per_seg;
 176         if (p->gc_mode == GC_GREEDY)
 177                 return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
 178         else if (p->gc_mode == GC_CB)
 179                 return UINT_MAX;
 180         else /* No other gc_mode */
 181                 return 0;
 182 }
 183
 184 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 185 {
 186         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 187         unsigned int secno;
 188
 189         /*
 190          * If the gc_type is FG_GC, we can select victim segments
 191          * selected by background GC before.
 192          * Those segments guarantee they have small valid blocks.
 193          */
 194         for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
 195                 if (sec_usage_check(sbi, secno))
 196                         continue;
 197                 clear_bit(secno, dirty_i->victim_secmap);
 198                 return secno * sbi->segs_per_sec;
 199         }
 200         return NULL_SEGNO;
 201 }
 202
 203 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 204 {
 205         struct sit_info *sit_i = SIT_I(sbi);
 206         unsigned int secno = GET_SECNO(sbi, segno);
 207         unsigned int start = secno * sbi->segs_per_sec;
 208         unsigned long long mtime = 0;
 209         unsigned int vblocks;
 210         unsigned char age = 0;
 211         unsigned char u;
 212         unsigned int i;
 213
 214         for (i = 0; i < sbi->segs_per_sec; i++)
 215                 mtime += get_seg_entry(sbi, start + i)->mtime;
 216         vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 217
 218         mtime = div_u64(mtime, sbi->segs_per_sec);
 219         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 220
 221         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 222
 223         /* Handle if the system time has changed by the user */
 224         if (mtime < sit_i->min_mtime)
 225                 sit_i->min_mtime = mtime;
 226         if (mtime > sit_i->max_mtime)
 227                 sit_i->max_mtime = mtime;
 228         if (sit_i->max_mtime != sit_i->min_mtime)
 229                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 230                                 sit_i->max_mtime - sit_i->min_mtime);
 231
 232         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 233 }
 234
 235 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 236                         unsigned int segno, struct victim_sel_policy *p)
 237 {
 238         if (p->alloc_mode == SSR)
 239                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 240
 241         /* alloc_mode == LFS */
 242         if (p->gc_mode == GC_GREEDY)
 243                 return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 244         else
 245                 return get_cb_cost(sbi, segno);
 246 }
 247
 248 /*
 249  * This function is called from two paths.
 250  * One is garbage collection and the other is SSR segment selection.
 251  * When it is called during GC, it just gets a victim segment
 252  * and it does not remove it from dirty seglist.
 253  * When it is called from SSR segment selection, it finds a segment
 254  * which has minimum valid blocks and removes it from dirty seglist.
 255  */
 256 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 257                 unsigned int *result, int gc_type, int type, char alloc_mode)
 258 {
 259         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 260         struct victim_sel_policy p;
 261         unsigned int secno, max_cost;
 262         int nsearched = 0;
 263
 264         mutex_lock(&dirty_i->seglist_lock);
 265
 266         p.alloc_mode = alloc_mode;
 267         select_policy(sbi, gc_type, type, &p);
 268
 269         p.min_segno = NULL_SEGNO;
 270         p.min_cost = max_cost = get_max_cost(sbi, &p);
 271
 272         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 273                 p.min_segno = check_bg_victims(sbi);
 274                 if (p.min_segno != NULL_SEGNO)
 275                         goto got_it;
 276         }
 277
 278         while (1) {
 279                 unsigned long cost;
 280                 unsigned int segno;
 281
 282                 segno = find_next_bit(p.dirty_segmap, MAIN_SEGS(sbi), p.offset);
 283                 if (segno >= MAIN_SEGS(sbi)) {
 284                         if (sbi->last_victim[p.gc_mode]) {
 285                                 sbi->last_victim[p.gc_mode] = 0;
 286                                 p.offset = 0;
 287                                 continue;
 288                         }
 289                         break;
 290                 }
 291
 292                 p.offset = segno + p.ofs_unit;
 293                 if (p.ofs_unit > 1)
 294                         p.offset -= segno % p.ofs_unit;
 295
 296                 secno = GET_SECNO(sbi, segno);
 297
 298                 if (sec_usage_check(sbi, secno))
 299                         continue;
 300                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 301                         continue;
 302
 303                 cost = get_gc_cost(sbi, segno, &p);
 304
 305                 if (p.min_cost > cost) {
 306                         p.min_segno = segno;
 307                         p.min_cost = cost;
 308                 } else if (unlikely(cost == max_cost)) {
 309                         continue;
 310                 }
 311
 312                 if (nsearched++ >= p.max_search) {
 313                         sbi->last_victim[p.gc_mode] = segno;
 314                         break;
 315                 }
 316         }
 317         if (p.min_segno != NULL_SEGNO) {
 318 got_it:
 319                 if (p.alloc_mode == LFS) {
 320                         secno = GET_SECNO(sbi, p.min_segno);
 321                         if (gc_type == FG_GC)
 322                                 sbi->cur_victim_sec = secno;
 323                         else
 324                                 set_bit(secno, dirty_i->victim_secmap);
 325                 }
 326                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 327
 328                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 329                                 sbi->cur_victim_sec,
 330                                 prefree_segments(sbi), free_segments(sbi));
 331         }
 332         mutex_unlock(&dirty_i->seglist_lock);
 333
 334         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 335 }
 336
 337 static const struct victim_selection default_v_ops = {
 338         .get_victim = get_victim_by_default,
 339 };
 340
 341 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 342 {
 343         struct inode_entry *ie;
 344
 345         ie = radix_tree_lookup(&gc_list->iroot, ino);
 346         if (ie)
 347                 return ie->inode;
 348         return NULL;
 349 }
 350
 351 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 352 {
 353         struct inode_entry *new_ie;
 354
 355         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
 356                 iput(inode);
 357                 return;
 358         }
 359         new_ie = f2fs_kmem_cache_alloc(winode_slab, GFP_NOFS);
 360         new_ie->inode = inode;
 361 retry:
 362         if (radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie)) {
 363                 cond_resched();
 364                 goto retry;
 365         }
 366         list_add_tail(&new_ie->list, &gc_list->ilist);
 367 }
 368
 369 static void put_gc_inode(struct gc_inode_list *gc_list)
 370 {
 371         struct inode_entry *ie, *next_ie;
 372         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
 373                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
 374                 iput(ie->inode);
 375                 list_del(&ie->list);
 376                 kmem_cache_free(winode_slab, ie);
 377         }
 378 }
 379
 380 static int check_valid_map(struct f2fs_sb_info *sbi,
 381                                 unsigned int segno, int offset)
 382 {
 383         struct sit_info *sit_i = SIT_I(sbi);
 384         struct seg_entry *sentry;
 385         int ret;
 386
 387         mutex_lock(&sit_i->sentry_lock);
 388         sentry = get_seg_entry(sbi, segno);
 389         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 390         mutex_unlock(&sit_i->sentry_lock);
 391         return ret;
 392 }
 393
 394 /*
 395  * This function compares node address got in summary with that in NAT.
 396  * On validity, copy that node with cold status, otherwise (invalid node)
 397  * ignore that.
 398  */
 399 static void gc_node_segment(struct f2fs_sb_info *sbi,
 400                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 401 {
 402         bool initial = true;
 403         struct f2fs_summary *entry;
 404         int off;
 405
 406 next_step:
 407         entry = sum;
 408
 409         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 410                 nid_t nid = le32_to_cpu(entry->nid);
 411                 struct page *node_page;
 412
 413                 /* stop BG_GC if there is not enough free sections. */
 414                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 415                         return;
 416
 417                 if (check_valid_map(sbi, segno, off) == 0)
 418                         continue;
 419
 420                 if (initial) {
 421                         ra_node_page(sbi, nid);
 422                         continue;
 423                 }
 424                 node_page = get_node_page(sbi, nid);
 425                 if (IS_ERR(node_page))
 426                         continue;
 427
 428                 /* block may become invalid during get_node_page */
 429                 if (check_valid_map(sbi, segno, off) == 0) {
 430                         f2fs_put_page(node_page, 1);
 431                         continue;
 432                 }
 433
 434                 /* set page dirty and write it */
 435                 if (gc_type == FG_GC) {
 436                         f2fs_wait_on_page_writeback(node_page, NODE);
 437                         set_page_dirty(node_page);
 438                 } else {
 439                         if (!PageWriteback(node_page))
 440                                 set_page_dirty(node_page);
 441                 }
 442                 f2fs_put_page(node_page, 1);
 443                 stat_inc_node_blk_count(sbi, 1);
 444         }
 445
 446         if (initial) {
 447                 initial = false;
 448                 goto next_step;
 449         }
 450
 451         if (gc_type == FG_GC) {
 452                 struct writeback_control wbc = {
 453                         .sync_mode = WB_SYNC_ALL,
 454                         .nr_to_write = LONG_MAX,
 455                         .for_reclaim = 0,
 456                 };
 457                 sync_node_pages(sbi, 0, &wbc);
 458
 459                 /*
 460                  * In the case of FG_GC, it'd be better to reclaim this victim
 461                  * completely.
 462                  */
 463                 if (get_valid_blocks(sbi, segno, 1) != 0)
 464                         goto next_step;
 465         }
 466 }
 467
 468 /*
 469  * Calculate start block index indicating the given node offset.
 470  * Be careful, caller should give this node offset only indicating direct node
 471  * blocks. If any node offsets, which point the other types of node blocks such
 472  * as indirect or double indirect node blocks, are given, it must be a caller's
 473  * bug.
 474  */
 475 block_t start_bidx_of_node(unsigned int node_ofs, struct f2fs_inode_info *fi)
 476 {
 477         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 478         unsigned int bidx;
 479
 480         if (node_ofs == 0)
 481                 return 0;
 482
 483         if (node_ofs <= 2) {
 484                 bidx = node_ofs - 1;
 485         } else if (node_ofs <= indirect_blks) {
 486                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 487                 bidx = node_ofs - 2 - dec;
 488         } else {
 489                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 490                 bidx = node_ofs - 5 - dec;
 491         }
 492         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi);
 493 }
 494
 495 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 496                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 497 {
 498         struct page *node_page;
 499         nid_t nid;
 500         unsigned int ofs_in_node;
 501         block_t source_blkaddr;
 502
 503         nid = le32_to_cpu(sum->nid);
 504         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 505
 506         node_page = get_node_page(sbi, nid);
 507         if (IS_ERR(node_page))
 508                 return 0;
 509
 510         get_node_info(sbi, nid, dni);
 511
 512         if (sum->version != dni->version) {
 513                 f2fs_put_page(node_page, 1);
 514                 return 0;
 515         }
 516
 517         *nofs = ofs_of_node(node_page);
 518         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 519         f2fs_put_page(node_page, 1);
 520
 521         if (source_blkaddr != blkaddr)
 522                 return 0;
 523         return 1;
 524 }
 525
 526 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
 527 {
 528         struct f2fs_io_info fio = {
 529                 .type = DATA,
 530                 .rw = WRITE_SYNC,
 531         };
 532
 533         if (gc_type == BG_GC) {
 534                 if (PageWriteback(page))
 535                         goto out;
 536                 set_page_dirty(page);
 537                 set_cold_data(page);
 538         } else {
 539                 f2fs_wait_on_page_writeback(page, DATA);
 540
 541                 if (clear_page_dirty_for_io(page))
 542                         inode_dec_dirty_pages(inode);
 543                 set_cold_data(page);
 544                 do_write_data_page(page, &fio);
 545                 clear_cold_data(page);
 546         }
 547 out:
 548         f2fs_put_page(page, 1);
 549 }
 550
 551 /*
 552  * This function tries to get parent node of victim data block, and identifies
 553  * data block validity. If the block is valid, copy that with cold status and
 554  * modify parent node.
 555  * If the parent node is not valid or the data block address is different,
 556  * the victim data block is ignored.
 557  */
 558 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 559                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 560 {
 561         struct super_block *sb = sbi->sb;
 562         struct f2fs_summary *entry;
 563         block_t start_addr;
 564         int off;
 565         int phase = 0;
 566
 567         start_addr = START_BLOCK(sbi, segno);
 568
 569 next_step:
 570         entry = sum;
 571
 572         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 573                 struct page *data_page;
 574                 struct inode *inode;
 575                 struct node_info dni; /* dnode info for the data */
 576                 unsigned int ofs_in_node, nofs;
 577                 block_t start_bidx;
 578
 579                 /* stop BG_GC if there is not enough free sections. */
 580                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 581                         return;
 582
 583                 if (check_valid_map(sbi, segno, off) == 0)
 584                         continue;
 585
 586                 if (phase == 0) {
 587                         ra_node_page(sbi, le32_to_cpu(entry->nid));
 588                         continue;
 589                 }
 590
 591                 /* Get an inode by ino with checking validity */
 592                 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
 593                         continue;
 594
 595                 if (phase == 1) {
 596                         ra_node_page(sbi, dni.ino);
 597                         continue;
 598                 }
 599
 600                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 601
 602                 if (phase == 2) {
 603                         inode = f2fs_iget(sb, dni.ino);
 604                         if (IS_ERR(inode) || is_bad_inode(inode))
 605                                 continue;
 606
 607                         start_bidx = start_bidx_of_node(nofs, F2FS_I(inode));
 608
 609                         data_page = find_data_page(inode,
 610                                         start_bidx + ofs_in_node, false);
 611                         if (IS_ERR(data_page)) {
 612                                 iput(inode);
 613                                 continue;
 614                         }
 615
 616                         f2fs_put_page(data_page, 0);
 617                         add_gc_inode(gc_list, inode);
 618                         continue;
 619                 }
 620
 621                 /* phase 3 */
 622                 inode = find_gc_inode(gc_list, dni.ino);
 623                 if (inode) {
 624                         start_bidx = start_bidx_of_node(nofs, F2FS_I(inode));
 625                         data_page = get_lock_data_page(inode,
 626                                                 start_bidx + ofs_in_node);
 627                         if (IS_ERR(data_page))
 628                                 continue;
 629                         move_data_page(inode, data_page, gc_type);
 630                         stat_inc_data_blk_count(sbi, 1);
 631                 }
 632         }
 633
 634         if (++phase < 4)
 635                 goto next_step;
 636
 637         if (gc_type == FG_GC) {
 638                 f2fs_submit_merged_bio(sbi, DATA, WRITE);
 639
 640                 /*
 641                  * In the case of FG_GC, it'd be better to reclaim this victim
 642                  * completely.
 643                  */
 644                 if (get_valid_blocks(sbi, segno, 1) != 0) {
 645                         phase = 2;
 646                         goto next_step;
 647                 }
 648         }
 649 }
 650
 651 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 652                         int gc_type)
 653 {
 654         struct sit_info *sit_i = SIT_I(sbi);
 655         int ret;
 656
 657         mutex_lock(&sit_i->sentry_lock);
 658         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
 659                                               NO_CHECK_TYPE, LFS);
 660         mutex_unlock(&sit_i->sentry_lock);
 661         return ret;
 662 }
 663
 664 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
 665                                 struct gc_inode_list *gc_list, int gc_type)
 666 {
 667         struct page *sum_page;
 668         struct f2fs_summary_block *sum;
 669         struct blk_plug plug;
 670
 671         /* read segment summary of victim */
 672         sum_page = get_sum_page(sbi, segno);
 673
 674         blk_start_plug(&plug);
 675
 676         sum = page_address(sum_page);
 677
 678         switch (GET_SUM_TYPE((&sum->footer))) {
 679         case SUM_TYPE_NODE:
 680                 gc_node_segment(sbi, sum->entries, segno, gc_type);
 681                 break;
 682         case SUM_TYPE_DATA:
 683                 gc_data_segment(sbi, sum->entries, gc_list, segno, gc_type);
 684                 break;
 685         }
 686         blk_finish_plug(&plug);
 687
 688         stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
 689         stat_inc_call_count(sbi->stat_info);
 690
 691         f2fs_put_page(sum_page, 1);
 692 }
 693
 694 int f2fs_gc(struct f2fs_sb_info *sbi)
 695 {
 696         unsigned int segno, i;
 697         int gc_type = BG_GC;
 698         int nfree = 0;
 699         int ret = -1;
 700         struct cp_control cpc;
 701         struct gc_inode_list gc_list = {
 702                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
 703                 .iroot = RADIX_TREE_INIT(GFP_NOFS),
 704         };
 705
 706         cpc.reason = test_opt(sbi, FASTBOOT) ? CP_UMOUNT : CP_SYNC;
 707
 708 gc_more:
 709         if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
 710                 goto stop;
 711         if (unlikely(f2fs_cp_error(sbi)))
 712                 goto stop;
 713
 714         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
 715                 gc_type = FG_GC;
 716                 write_checkpoint(sbi, &cpc);
 717         }
 718
 719         if (!__get_victim(sbi, &segno, gc_type))
 720                 goto stop;
 721         ret = 0;
 722
 723         /* readahead multi ssa blocks those have contiguous address */
 724         if (sbi->segs_per_sec > 1)
 725                 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), sbi->segs_per_sec,
 726                                                                 META_SSA);
 727
 728         for (i = 0; i < sbi->segs_per_sec; i++)
 729                 do_garbage_collect(sbi, segno + i, &gc_list, gc_type);
 730
 731         if (gc_type == FG_GC) {
 732                 sbi->cur_victim_sec = NULL_SEGNO;
 733                 nfree++;
 734                 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
 735         }
 736
 737         if (has_not_enough_free_secs(sbi, nfree))
 738                 goto gc_more;
 739
 740         if (gc_type == FG_GC)
 741                 write_checkpoint(sbi, &cpc);
 742 stop:
 743         mutex_unlock(&sbi->gc_mutex);
 744
 745         put_gc_inode(&gc_list);
 746         return ret;
 747 }
 748
 749 void build_gc_manager(struct f2fs_sb_info *sbi)
 750 {
 751         DIRTY_I(sbi)->v_ops = &default_v_ops;
 752 }
 753
 754 int __init create_gc_caches(void)
 755 {
 756         winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
 757                         sizeof(struct inode_entry));
 758         if (!winode_slab)
 759                 return -ENOMEM;
 760         return 0;
 761 }
 762
 763 void destroy_gc_caches(void)
 764 {
 765         kmem_cache_destroy(winode_slab);
 766 }