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_wait_on_page_writeback(node_page, NODE, true);
 426                         set_page_dirty(node_page);
 427                 } else {
 428                         if (!PageWriteback(node_page))
 429                                 set_page_dirty(node_page);
 430                 }
 431                 f2fs_put_page(node_page, 1);
 432                 stat_inc_node_blk_count(sbi, 1);
 433         }
 434
 435         if (initial) {
 436                 initial = false;
 437                 goto next_step;
 438         }
 439
 440         if (gc_type == FG_GC) {
 441                 struct writeback_control wbc = {
 442                         .sync_mode = WB_SYNC_ALL,
 443                         .nr_to_write = LONG_MAX,
 444                         .for_reclaim = 0,
 445                 };
 446                 sync_node_pages(sbi, 0, &wbc);
 447
 448                 /*
 449                  * In the case of FG_GC, it'd be better to reclaim this victim
 450                  * completely.
 451                  */
 452                 if (get_valid_blocks(sbi, segno, 1) != 0)
 453                         goto next_step;
 454         }
 455 }
 456
 457 /*
 458  * Calculate start block index indicating the given node offset.
 459  * Be careful, caller should give this node offset only indicating direct node
 460  * blocks. If any node offsets, which point the other types of node blocks such
 461  * as indirect or double indirect node blocks, are given, it must be a caller's
 462  * bug.
 463  */
 464 block_t start_bidx_of_node(unsigned int node_ofs, struct f2fs_inode_info *fi)
 465 {
 466         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 467         unsigned int bidx;
 468
 469         if (node_ofs == 0)
 470                 return 0;
 471
 472         if (node_ofs <= 2) {
 473                 bidx = node_ofs - 1;
 474         } else if (node_ofs <= indirect_blks) {
 475                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 476                 bidx = node_ofs - 2 - dec;
 477         } else {
 478                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 479                 bidx = node_ofs - 5 - dec;
 480         }
 481         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi);
 482 }
 483
 484 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 485                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 486 {
 487         struct page *node_page;
 488         nid_t nid;
 489         unsigned int ofs_in_node;
 490         block_t source_blkaddr;
 491
 492         nid = le32_to_cpu(sum->nid);
 493         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 494
 495         node_page = get_node_page(sbi, nid);
 496         if (IS_ERR(node_page))
 497                 return 0;
 498
 499         get_node_info(sbi, nid, dni);
 500
 501         if (sum->version != dni->version) {
 502                 f2fs_put_page(node_page, 1);
 503                 return 0;
 504         }
 505
 506         *nofs = ofs_of_node(node_page);
 507         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 508         f2fs_put_page(node_page, 1);
 509
 510         if (source_blkaddr != blkaddr)
 511                 return 0;
 512         return 1;
 513 }
 514
 515 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
 516 {
 517         if (gc_type == BG_GC) {
 518                 if (PageWriteback(page))
 519                         goto out;
 520                 set_page_dirty(page);
 521                 set_cold_data(page);
 522         } else {
 523                 struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
 524
 525                 f2fs_wait_on_page_writeback(page, DATA, true);
 526
 527                 if (clear_page_dirty_for_io(page) &&
 528                         S_ISDIR(inode->i_mode)) {
 529                         dec_page_count(sbi, F2FS_DIRTY_DENTS);
 530                         inode_dec_dirty_dents(inode);
 531                 }
 532                 set_cold_data(page);
 533                 do_write_data_page(page);
 534                 clear_cold_data(page);
 535         }
 536 out:
 537         f2fs_put_page(page, 1);
 538 }
 539
 540 /*
 541  * This function tries to get parent node of victim data block, and identifies
 542  * data block validity. If the block is valid, copy that with cold status and
 543  * modify parent node.
 544  * If the parent node is not valid or the data block address is different,
 545  * the victim data block is ignored.
 546  */
 547 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 548                 struct list_head *ilist, unsigned int segno, int gc_type)
 549 {
 550         struct super_block *sb = sbi->sb;
 551         struct f2fs_summary *entry;
 552         block_t start_addr;
 553         int off;
 554         int phase = 0;
 555
 556         start_addr = START_BLOCK(sbi, segno);
 557
 558 next_step:
 559         entry = sum;
 560
 561         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 562                 struct page *data_page;
 563                 struct inode *inode;
 564                 struct node_info dni; /* dnode info for the data */
 565                 unsigned int ofs_in_node, nofs;
 566                 block_t start_bidx;
 567
 568                 /* stop BG_GC if there is not enough free sections. */
 569                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
 570                         return;
 571
 572                 if (check_valid_map(sbi, segno, off) == 0)
 573                         continue;
 574
 575                 if (phase == 0) {
 576                         ra_node_page(sbi, le32_to_cpu(entry->nid));
 577                         continue;
 578                 }
 579
 580                 /* Get an inode by ino with checking validity */
 581                 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
 582                         continue;
 583
 584                 if (phase == 1) {
 585                         ra_node_page(sbi, dni.ino);
 586                         continue;
 587                 }
 588
 589                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 590
 591                 if (phase == 2) {
 592                         inode = f2fs_iget(sb, dni.ino);
 593                         if (IS_ERR(inode))
 594                                 continue;
 595
 596                         start_bidx = start_bidx_of_node(nofs, F2FS_I(inode));
 597
 598                         data_page = find_data_page(inode,
 599                                         start_bidx + ofs_in_node, false);
 600                         if (IS_ERR(data_page))
 601                                 goto next_iput;
 602
 603                         f2fs_put_page(data_page, 0);
 604                         add_gc_inode(inode, ilist);
 605                 } else {
 606                         inode = find_gc_inode(dni.ino, ilist);
 607                         if (inode) {
 608                                 start_bidx = start_bidx_of_node(nofs,
 609                                                                 F2FS_I(inode));
 610                                 data_page = get_lock_data_page(inode,
 611                                                 start_bidx + ofs_in_node);
 612                                 if (IS_ERR(data_page))
 613                                         continue;
 614                                 move_data_page(inode, data_page, gc_type);
 615                                 stat_inc_data_blk_count(sbi, 1);
 616                         }
 617                 }
 618                 continue;
 619 next_iput:
 620                 iput(inode);
 621         }
 622
 623         if (++phase < 4)
 624                 goto next_step;
 625
 626         if (gc_type == FG_GC) {
 627                 f2fs_submit_bio(sbi, DATA, true);
 628
 629                 /*
 630                  * In the case of FG_GC, it'd be better to reclaim this victim
 631                  * completely.
 632                  */
 633                 if (get_valid_blocks(sbi, segno, 1) != 0) {
 634                         phase = 2;
 635                         goto next_step;
 636                 }
 637         }
 638 }
 639
 640 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 641                                                 int gc_type, int type)
 642 {
 643         struct sit_info *sit_i = SIT_I(sbi);
 644         int ret;
 645         mutex_lock(&sit_i->sentry_lock);
 646         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
 647         mutex_unlock(&sit_i->sentry_lock);
 648         return ret;
 649 }
 650
 651 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
 652                                 struct list_head *ilist, int gc_type)
 653 {
 654         struct page *sum_page;
 655         struct f2fs_summary_block *sum;
 656         struct blk_plug plug;
 657
 658         /* read segment summary of victim */
 659         sum_page = get_sum_page(sbi, segno);
 660         if (IS_ERR(sum_page))
 661                 return;
 662
 663         blk_start_plug(&plug);
 664
 665         sum = page_address(sum_page);
 666
 667         switch (GET_SUM_TYPE((&sum->footer))) {
 668         case SUM_TYPE_NODE:
 669                 gc_node_segment(sbi, sum->entries, segno, gc_type);
 670                 break;
 671         case SUM_TYPE_DATA:
 672                 gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
 673                 break;
 674         }
 675         blk_finish_plug(&plug);
 676
 677         stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
 678         stat_inc_call_count(sbi->stat_info);
 679
 680         f2fs_put_page(sum_page, 1);
 681 }
 682
 683 int f2fs_gc(struct f2fs_sb_info *sbi)
 684 {
 685         struct list_head ilist;
 686         unsigned int segno, i;
 687         int gc_type = BG_GC;
 688         int nfree = 0;
 689         int ret = -1;
 690
 691         INIT_LIST_HEAD(&ilist);
 692 gc_more:
 693         if (!(sbi->sb->s_flags & MS_ACTIVE))
 694                 goto stop;
 695
 696         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
 697                 gc_type = FG_GC;
 698                 write_checkpoint(sbi, false);
 699         }
 700
 701         if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
 702                 goto stop;
 703         ret = 0;
 704
 705         for (i = 0; i < sbi->segs_per_sec; i++)
 706                 do_garbage_collect(sbi, segno + i, &ilist, gc_type);
 707
 708         if (gc_type == FG_GC) {
 709                 sbi->cur_victim_sec = NULL_SEGNO;
 710                 nfree++;
 711                 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
 712         }
 713
 714         if (has_not_enough_free_secs(sbi, nfree))
 715                 goto gc_more;
 716
 717         if (gc_type == FG_GC)
 718                 write_checkpoint(sbi, false);
 719 stop:
 720         mutex_unlock(&sbi->gc_mutex);
 721
 722         put_gc_inode(&ilist);
 723         return ret;
 724 }
 725
 726 void build_gc_manager(struct f2fs_sb_info *sbi)
 727 {
 728         DIRTY_I(sbi)->v_ops = &default_v_ops;
 729 }
 730
 731 int __init create_gc_caches(void)
 732 {
 733         winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
 734                         sizeof(struct inode_entry), NULL);
 735         if (!winode_slab)
 736                 return -ENOMEM;
 737         return 0;
 738 }
 739
 740 void destroy_gc_caches(void)
 741 {
 742         kmem_cache_destroy(winode_slab);
 743 }