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
  20 #include "f2fs.h"
  21 #include "node.h"
  22 #include "segment.h"
  23 #include "gc.h"
  24 #include <trace/events/f2fs.h>
  25
  26 static int gc_thread_func(void *data)
  27 {
  28         struct f2fs_sb_info *sbi = data;
  29         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
  30         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
  31         long wait_ms;
  32
  33         wait_ms = gc_th->min_sleep_time;
  34
  35         set_freezable();
  36         do {
  37                 wait_event_interruptible_timeout(*wq,
  38                                 kthread_should_stop() || freezing(current),
  39                                 msecs_to_jiffies(wait_ms));
  40
  41                 if (try_to_freeze())
  42                         continue;
  43                 if (kthread_should_stop())
  44                         break;
  45
  46                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
  47                         increase_sleep_time(gc_th, &wait_ms);
  48                         continue;
  49                 }
  50
  51 #ifdef CONFIG_F2FS_FAULT_INJECTION
  52                 if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
  53                         f2fs_show_injection_info(FAULT_CHECKPOINT);
  54                         f2fs_stop_checkpoint(sbi, false);
  55                 }
  56 #endif
  57
  58                 /*
  59                  * [GC triggering condition]
  60                  * 0. GC is not conducted currently.
  61                  * 1. There are enough dirty segments.
  62                  * 2. IO subsystem is idle by checking the # of writeback pages.
  63                  * 3. IO subsystem is idle by checking the # of requests in
  64                  *    bdev's request list.
  65                  *
  66                  * Note) We have to avoid triggering GCs frequently.
  67                  * Because it is possible that some segments can be
  68                  * invalidated soon after by user update or deletion.
  69                  * So, I'd like to wait some time to collect dirty segments.
  70                  */
  71                 if (!mutex_trylock(&sbi->gc_mutex))
  72                         continue;
  73
  74                 if (!is_idle(sbi)) {
  75                         increase_sleep_time(gc_th, &wait_ms);
  76                         mutex_unlock(&sbi->gc_mutex);
  77                         continue;
  78                 }
  79
  80                 if (has_enough_invalid_blocks(sbi))
  81                         decrease_sleep_time(gc_th, &wait_ms);
  82                 else
  83                         increase_sleep_time(gc_th, &wait_ms);
  84
  85                 stat_inc_bggc_count(sbi);
  86
  87                 /* if return value is not zero, no victim was selected */
  88                 if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC), true, NULL_SEGNO))
  89                         wait_ms = gc_th->no_gc_sleep_time;
  90
  91                 trace_f2fs_background_gc(sbi->sb, wait_ms,
  92                                 prefree_segments(sbi), free_segments(sbi));
  93
  94                 /* balancing f2fs's metadata periodically */
  95                 f2fs_balance_fs_bg(sbi);
  96
  97         } while (!kthread_should_stop());
  98         return 0;
  99 }
 100
 101 int start_gc_thread(struct f2fs_sb_info *sbi)
 102 {
 103         struct f2fs_gc_kthread *gc_th;
 104         dev_t dev = sbi->sb->s_bdev->bd_dev;
 105         int err = 0;
 106
 107         gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
 108         if (!gc_th) {
 109                 err = -ENOMEM;
 110                 goto out;
 111         }
 112
 113         gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
 114         gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
 115         gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
 116
 117         gc_th->gc_idle = 0;
 118
 119         sbi->gc_thread = gc_th;
 120         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 121         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 122                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 123         if (IS_ERR(gc_th->f2fs_gc_task)) {
 124                 err = PTR_ERR(gc_th->f2fs_gc_task);
 125                 kfree(gc_th);
 126                 sbi->gc_thread = NULL;
 127         }
 128 out:
 129         return err;
 130 }
 131
 132 void stop_gc_thread(struct f2fs_sb_info *sbi)
 133 {
 134         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 135         if (!gc_th)
 136                 return;
 137         kthread_stop(gc_th->f2fs_gc_task);
 138         kfree(gc_th);
 139         sbi->gc_thread = NULL;
 140 }
 141
 142 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
 143 {
 144         int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 145
 146         if (gc_th && gc_th->gc_idle) {
 147                 if (gc_th->gc_idle == 1)
 148                         gc_mode = GC_CB;
 149                 else if (gc_th->gc_idle == 2)
 150                         gc_mode = GC_GREEDY;
 151         }
 152         return gc_mode;
 153 }
 154
 155 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 156                         int type, struct victim_sel_policy *p)
 157 {
 158         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 159
 160         if (p->alloc_mode == SSR) {
 161                 p->gc_mode = GC_GREEDY;
 162                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 163                 p->max_search = dirty_i->nr_dirty[type];
 164                 p->ofs_unit = 1;
 165         } else {
 166                 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
 167                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 168                 p->max_search = dirty_i->nr_dirty[DIRTY];
 169                 p->ofs_unit = sbi->segs_per_sec;
 170         }
 171
 172         /* we need to check every dirty segments in the FG_GC case */
 173         if (gc_type != FG_GC && p->max_search > sbi->max_victim_search)
 174                 p->max_search = sbi->max_victim_search;
 175
 176         /* let's select beginning hot/small space first */
 177         if (type == CURSEG_HOT_DATA || IS_NODESEG(type))
 178                 p->offset = 0;
 179         else
 180                 p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
 181 }
 182
 183 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 184                                 struct victim_sel_policy *p)
 185 {
 186         /* SSR allocates in a segment unit */
 187         if (p->alloc_mode == SSR)
 188                 return sbi->blocks_per_seg;
 189         if (p->gc_mode == GC_GREEDY)
 190                 return 2 * sbi->blocks_per_seg * p->ofs_unit;
 191         else if (p->gc_mode == GC_CB)
 192                 return UINT_MAX;
 193         else /* No other gc_mode */
 194                 return 0;
 195 }
 196
 197 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 198 {
 199         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 200         unsigned int secno;
 201
 202         /*
 203          * If the gc_type is FG_GC, we can select victim segments
 204          * selected by background GC before.
 205          * Those segments guarantee they have small valid blocks.
 206          */
 207         for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
 208                 if (sec_usage_check(sbi, secno))
 209                         continue;
 210
 211                 if (no_fggc_candidate(sbi, secno))
 212                         continue;
 213
 214                 clear_bit(secno, dirty_i->victim_secmap);
 215                 return GET_SEG_FROM_SEC(sbi, secno);
 216         }
 217         return NULL_SEGNO;
 218 }
 219
 220 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 221 {
 222         struct sit_info *sit_i = SIT_I(sbi);
 223         unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
 224         unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
 225         unsigned long long mtime = 0;
 226         unsigned int vblocks;
 227         unsigned char age = 0;
 228         unsigned char u;
 229         unsigned int i;
 230
 231         for (i = 0; i < sbi->segs_per_sec; i++)
 232                 mtime += get_seg_entry(sbi, start + i)->mtime;
 233         vblocks = get_valid_blocks(sbi, segno, true);
 234
 235         mtime = div_u64(mtime, sbi->segs_per_sec);
 236         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 237
 238         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 239
 240         /* Handle if the system time has changed by the user */
 241         if (mtime < sit_i->min_mtime)
 242                 sit_i->min_mtime = mtime;
 243         if (mtime > sit_i->max_mtime)
 244                 sit_i->max_mtime = mtime;
 245         if (sit_i->max_mtime != sit_i->min_mtime)
 246                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 247                                 sit_i->max_mtime - sit_i->min_mtime);
 248
 249         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 250 }
 251
 252 static unsigned int get_greedy_cost(struct f2fs_sb_info *sbi,
 253                                                 unsigned int segno)
 254 {
 255         unsigned int valid_blocks =
 256                         get_valid_blocks(sbi, segno, true);
 257
 258         return IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 259                                 valid_blocks * 2 : valid_blocks;
 260 }
 261
 262 static unsigned int get_ssr_cost(struct f2fs_sb_info *sbi,
 263                                                 unsigned int segno)
 264 {
 265         struct seg_entry *se = get_seg_entry(sbi, segno);
 266
 267         return se->ckpt_valid_blocks > se->valid_blocks ?
 268                                 se->ckpt_valid_blocks : se->valid_blocks;
 269 }
 270
 271 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 272                         unsigned int segno, struct victim_sel_policy *p)
 273 {
 274         if (p->alloc_mode == SSR)
 275                 return get_ssr_cost(sbi, segno);
 276
 277         /* alloc_mode == LFS */
 278         if (p->gc_mode == GC_GREEDY)
 279                 return get_greedy_cost(sbi, segno);
 280         else
 281                 return get_cb_cost(sbi, segno);
 282 }
 283
 284 static unsigned int count_bits(const unsigned long *addr,
 285                                 unsigned int offset, unsigned int len)
 286 {
 287         unsigned int end = offset + len, sum = 0;
 288
 289         while (offset < end) {
 290                 if (test_bit(offset++, addr))
 291                         ++sum;
 292         }
 293         return sum;
 294 }
 295
 296 /*
 297  * This function is called from two paths.
 298  * One is garbage collection and the other is SSR segment selection.
 299  * When it is called during GC, it just gets a victim segment
 300  * and it does not remove it from dirty seglist.
 301  * When it is called from SSR segment selection, it finds a segment
 302  * which has minimum valid blocks and removes it from dirty seglist.
 303  */
 304 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 305                 unsigned int *result, int gc_type, int type, char alloc_mode)
 306 {
 307         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 308         struct sit_info *sm = SIT_I(sbi);
 309         struct victim_sel_policy p;
 310         unsigned int secno, last_victim;
 311         unsigned int last_segment = MAIN_SEGS(sbi);
 312         unsigned int nsearched = 0;
 313
 314         mutex_lock(&dirty_i->seglist_lock);
 315
 316         p.alloc_mode = alloc_mode;
 317         select_policy(sbi, gc_type, type, &p);
 318
 319         p.min_segno = NULL_SEGNO;
 320         p.min_cost = get_max_cost(sbi, &p);
 321
 322         if (*result != NULL_SEGNO) {
 323                 if (IS_DATASEG(get_seg_entry(sbi, *result)->type) &&
 324                         get_valid_blocks(sbi, *result, false) &&
 325                         !sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
 326                         p.min_segno = *result;
 327                 goto out;
 328         }
 329
 330         if (p.max_search == 0)
 331                 goto out;
 332
 333         last_victim = sm->last_victim[p.gc_mode];
 334         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 335                 p.min_segno = check_bg_victims(sbi);
 336                 if (p.min_segno != NULL_SEGNO)
 337                         goto got_it;
 338         }
 339
 340         while (1) {
 341                 unsigned long cost;
 342                 unsigned int segno;
 343
 344                 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
 345                 if (segno >= last_segment) {
 346                         if (sm->last_victim[p.gc_mode]) {
 347                                 last_segment =
 348                                         sm->last_victim[p.gc_mode];
 349                                 sm->last_victim[p.gc_mode] = 0;
 350                                 p.offset = 0;
 351                                 continue;
 352                         }
 353                         break;
 354                 }
 355
 356                 p.offset = segno + p.ofs_unit;
 357                 if (p.ofs_unit > 1) {
 358                         p.offset -= segno % p.ofs_unit;
 359                         nsearched += count_bits(p.dirty_segmap,
 360                                                 p.offset - p.ofs_unit,
 361                                                 p.ofs_unit);
 362                 } else {
 363                         nsearched++;
 364                 }
 365
 366                 secno = GET_SEC_FROM_SEG(sbi, segno);
 367
 368                 if (sec_usage_check(sbi, secno))
 369                         goto next;
 370                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 371                         goto next;
 372                 if (gc_type == FG_GC && p.alloc_mode == LFS &&
 373                                         no_fggc_candidate(sbi, secno))
 374                         goto next;
 375
 376                 cost = get_gc_cost(sbi, segno, &p);
 377
 378                 if (p.min_cost > cost) {
 379                         p.min_segno = segno;
 380                         p.min_cost = cost;
 381                 }
 382 next:
 383                 if (nsearched >= p.max_search) {
 384                         if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
 385                                 sm->last_victim[p.gc_mode] = last_victim + 1;
 386                         else
 387                                 sm->last_victim[p.gc_mode] = segno + 1;
 388                         sm->last_victim[p.gc_mode] %= MAIN_SEGS(sbi);
 389                         break;
 390                 }
 391         }
 392         if (p.min_segno != NULL_SEGNO) {
 393 got_it:
 394                 if (p.alloc_mode == LFS) {
 395                         secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
 396                         if (gc_type == FG_GC)
 397                                 sbi->cur_victim_sec = secno;
 398                         else
 399                                 set_bit(secno, dirty_i->victim_secmap);
 400                 }
 401                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 402
 403                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 404                                 sbi->cur_victim_sec,
 405                                 prefree_segments(sbi), free_segments(sbi));
 406         }
 407 out:
 408         mutex_unlock(&dirty_i->seglist_lock);
 409
 410         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 411 }
 412
 413 static const struct victim_selection default_v_ops = {
 414         .get_victim = get_victim_by_default,
 415 };
 416
 417 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 418 {
 419         struct inode_entry *ie;
 420
 421         ie = radix_tree_lookup(&gc_list->iroot, ino);
 422         if (ie)
 423                 return ie->inode;
 424         return NULL;
 425 }
 426
 427 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 428 {
 429         struct inode_entry *new_ie;
 430
 431         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
 432                 iput(inode);
 433                 return;
 434         }
 435         new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
 436         new_ie->inode = inode;
 437
 438         f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
 439         list_add_tail(&new_ie->list, &gc_list->ilist);
 440 }
 441
 442 static void put_gc_inode(struct gc_inode_list *gc_list)
 443 {
 444         struct inode_entry *ie, *next_ie;
 445         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
 446                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
 447                 iput(ie->inode);
 448                 list_del(&ie->list);
 449                 kmem_cache_free(inode_entry_slab, ie);
 450         }
 451 }
 452
 453 static int check_valid_map(struct f2fs_sb_info *sbi,
 454                                 unsigned int segno, int offset)
 455 {
 456         struct sit_info *sit_i = SIT_I(sbi);
 457         struct seg_entry *sentry;
 458         int ret;
 459
 460         mutex_lock(&sit_i->sentry_lock);
 461         sentry = get_seg_entry(sbi, segno);
 462         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 463         mutex_unlock(&sit_i->sentry_lock);
 464         return ret;
 465 }
 466
 467 /*
 468  * This function compares node address got in summary with that in NAT.
 469  * On validity, copy that node with cold status, otherwise (invalid node)
 470  * ignore that.
 471  */
 472 static void gc_node_segment(struct f2fs_sb_info *sbi,
 473                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 474 {
 475         struct f2fs_summary *entry;
 476         block_t start_addr;
 477         int off;
 478         int phase = 0;
 479
 480         start_addr = START_BLOCK(sbi, segno);
 481
 482 next_step:
 483         entry = sum;
 484
 485         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 486                 nid_t nid = le32_to_cpu(entry->nid);
 487                 struct page *node_page;
 488                 struct node_info ni;
 489
 490                 /* stop BG_GC if there is not enough free sections. */
 491                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 492                         return;
 493
 494                 if (check_valid_map(sbi, segno, off) == 0)
 495                         continue;
 496
 497                 if (phase == 0) {
 498                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 499                                                         META_NAT, true);
 500                         continue;
 501                 }
 502
 503                 if (phase == 1) {
 504                         ra_node_page(sbi, nid);
 505                         continue;
 506                 }
 507
 508                 /* phase == 2 */
 509                 node_page = get_node_page(sbi, nid);
 510                 if (IS_ERR(node_page))
 511                         continue;
 512
 513                 /* block may become invalid during get_node_page */
 514                 if (check_valid_map(sbi, segno, off) == 0) {
 515                         f2fs_put_page(node_page, 1);
 516                         continue;
 517                 }
 518
 519                 get_node_info(sbi, nid, &ni);
 520                 if (ni.blk_addr != start_addr + off) {
 521                         f2fs_put_page(node_page, 1);
 522                         continue;
 523                 }
 524
 525                 move_node_page(node_page, gc_type);
 526                 stat_inc_node_blk_count(sbi, 1, gc_type);
 527         }
 528
 529         if (++phase < 3)
 530                 goto next_step;
 531 }
 532
 533 /*
 534  * Calculate start block index indicating the given node offset.
 535  * Be careful, caller should give this node offset only indicating direct node
 536  * blocks. If any node offsets, which point the other types of node blocks such
 537  * as indirect or double indirect node blocks, are given, it must be a caller's
 538  * bug.
 539  */
 540 block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
 541 {
 542         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 543         unsigned int bidx;
 544
 545         if (node_ofs == 0)
 546                 return 0;
 547
 548         if (node_ofs <= 2) {
 549                 bidx = node_ofs - 1;
 550         } else if (node_ofs <= indirect_blks) {
 551                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 552                 bidx = node_ofs - 2 - dec;
 553         } else {
 554                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 555                 bidx = node_ofs - 5 - dec;
 556         }
 557         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
 558 }
 559
 560 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 561                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 562 {
 563         struct page *node_page;
 564         nid_t nid;
 565         unsigned int ofs_in_node;
 566         block_t source_blkaddr;
 567
 568         nid = le32_to_cpu(sum->nid);
 569         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 570
 571         node_page = get_node_page(sbi, nid);
 572         if (IS_ERR(node_page))
 573                 return false;
 574
 575         get_node_info(sbi, nid, dni);
 576
 577         if (sum->version != dni->version) {
 578                 f2fs_msg(sbi->sb, KERN_WARNING,
 579                                 "%s: valid data with mismatched node version.",
 580                                 __func__);
 581                 set_sbi_flag(sbi, SBI_NEED_FSCK);
 582         }
 583
 584         *nofs = ofs_of_node(node_page);
 585         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 586         f2fs_put_page(node_page, 1);
 587
 588         if (source_blkaddr != blkaddr)
 589                 return false;
 590         return true;
 591 }
 592
 593 static void move_encrypted_block(struct inode *inode, block_t bidx,
 594                                                         unsigned int segno, int off)
 595 {
 596         struct f2fs_io_info fio = {
 597                 .sbi = F2FS_I_SB(inode),
 598                 .type = DATA,
 599                 .temp = COLD,
 600                 .op = REQ_OP_READ,
 601                 .op_flags = 0,
 602                 .encrypted_page = NULL,
 603                 .in_list = false,
 604         };
 605         struct dnode_of_data dn;
 606         struct f2fs_summary sum;
 607         struct node_info ni;
 608         struct page *page;
 609         block_t newaddr;
 610         int err;
 611
 612         /* do not read out */
 613         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 614         if (!page)
 615                 return;
 616
 617         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 618                 goto out;
 619
 620         if (f2fs_is_atomic_file(inode))
 621                 goto out;
 622
 623         set_new_dnode(&dn, inode, NULL, NULL, 0);
 624         err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
 625         if (err)
 626                 goto out;
 627
 628         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 629                 ClearPageUptodate(page);
 630                 goto put_out;
 631         }
 632
 633         /*
 634          * don't cache encrypted data into meta inode until previous dirty
 635          * data were writebacked to avoid racing between GC and flush.
 636          */
 637         f2fs_wait_on_page_writeback(page, DATA, true);
 638
 639         get_node_info(fio.sbi, dn.nid, &ni);
 640         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
 641
 642         /* read page */
 643         fio.page = page;
 644         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 645
 646         allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 647                                         &sum, CURSEG_COLD_DATA, NULL, false);
 648
 649         fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
 650                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
 651         if (!fio.encrypted_page) {
 652                 err = -ENOMEM;
 653                 goto recover_block;
 654         }
 655
 656         err = f2fs_submit_page_bio(&fio);
 657         if (err)
 658                 goto put_page_out;
 659
 660         /* write page */
 661         lock_page(fio.encrypted_page);
 662
 663         if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
 664                 err = -EIO;
 665                 goto put_page_out;
 666         }
 667         if (unlikely(!PageUptodate(fio.encrypted_page))) {
 668                 err = -EIO;
 669                 goto put_page_out;
 670         }
 671
 672         set_page_dirty(fio.encrypted_page);
 673         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
 674         if (clear_page_dirty_for_io(fio.encrypted_page))
 675                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
 676
 677         set_page_writeback(fio.encrypted_page);
 678
 679         /* allocate block address */
 680         f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
 681
 682         fio.op = REQ_OP_WRITE;
 683         fio.op_flags = REQ_SYNC;
 684         fio.new_blkaddr = newaddr;
 685         f2fs_submit_page_write(&fio);
 686
 687         f2fs_update_data_blkaddr(&dn, newaddr);
 688         set_inode_flag(inode, FI_APPEND_WRITE);
 689         if (page->index == 0)
 690                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 691 put_page_out:
 692         f2fs_put_page(fio.encrypted_page, 1);
 693 recover_block:
 694         if (err)
 695                 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
 696                                                                 true, true);
 697 put_out:
 698         f2fs_put_dnode(&dn);
 699 out:
 700         f2fs_put_page(page, 1);
 701 }
 702
 703 static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
 704                                                         unsigned int segno, int off)
 705 {
 706         struct page *page;
 707
 708         page = get_lock_data_page(inode, bidx, true);
 709         if (IS_ERR(page))
 710                 return;
 711
 712         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 713                 goto out;
 714
 715         if (f2fs_is_atomic_file(inode))
 716                 goto out;
 717
 718         if (gc_type == BG_GC) {
 719                 if (PageWriteback(page))
 720                         goto out;
 721                 set_page_dirty(page);
 722                 set_cold_data(page);
 723         } else {
 724                 struct f2fs_io_info fio = {
 725                         .sbi = F2FS_I_SB(inode),
 726                         .type = DATA,
 727                         .temp = COLD,
 728                         .op = REQ_OP_WRITE,
 729                         .op_flags = REQ_SYNC,
 730                         .old_blkaddr = NULL_ADDR,
 731                         .page = page,
 732                         .encrypted_page = NULL,
 733                         .need_lock = LOCK_REQ,
 734                 };
 735                 bool is_dirty = PageDirty(page);
 736                 int err;
 737
 738 retry:
 739                 set_page_dirty(page);
 740                 f2fs_wait_on_page_writeback(page, DATA, true);
 741                 if (clear_page_dirty_for_io(page)) {
 742                         inode_dec_dirty_pages(inode);
 743                         remove_dirty_inode(inode);
 744                 }
 745
 746                 set_cold_data(page);
 747
 748                 err = do_write_data_page(&fio);
 749                 if (err == -ENOMEM && is_dirty) {
 750                         congestion_wait(BLK_RW_ASYNC, HZ/50);
 751                         goto retry;
 752                 }
 753         }
 754 out:
 755         f2fs_put_page(page, 1);
 756 }
 757
 758 /*
 759  * This function tries to get parent node of victim data block, and identifies
 760  * data block validity. If the block is valid, copy that with cold status and
 761  * modify parent node.
 762  * If the parent node is not valid or the data block address is different,
 763  * the victim data block is ignored.
 764  */
 765 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 766                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 767 {
 768         struct super_block *sb = sbi->sb;
 769         struct f2fs_summary *entry;
 770         block_t start_addr;
 771         int off;
 772         int phase = 0;
 773
 774         start_addr = START_BLOCK(sbi, segno);
 775
 776 next_step:
 777         entry = sum;
 778
 779         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 780                 struct page *data_page;
 781                 struct inode *inode;
 782                 struct node_info dni; /* dnode info for the data */
 783                 unsigned int ofs_in_node, nofs;
 784                 block_t start_bidx;
 785                 nid_t nid = le32_to_cpu(entry->nid);
 786
 787                 /* stop BG_GC if there is not enough free sections. */
 788                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 789                         return;
 790
 791                 if (check_valid_map(sbi, segno, off) == 0)
 792                         continue;
 793
 794                 if (phase == 0) {
 795                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 796                                                         META_NAT, true);
 797                         continue;
 798                 }
 799
 800                 if (phase == 1) {
 801                         ra_node_page(sbi, nid);
 802                         continue;
 803                 }
 804
 805                 /* Get an inode by ino with checking validity */
 806                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
 807                         continue;
 808
 809                 if (phase == 2) {
 810                         ra_node_page(sbi, dni.ino);
 811                         continue;
 812                 }
 813
 814                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 815
 816                 if (phase == 3) {
 817                         inode = f2fs_iget(sb, dni.ino);
 818                         if (IS_ERR(inode) || is_bad_inode(inode))
 819                                 continue;
 820
 821                         /* if encrypted inode, let's go phase 3 */
 822                         if (f2fs_encrypted_inode(inode) &&
 823                                                 S_ISREG(inode->i_mode)) {
 824                                 add_gc_inode(gc_list, inode);
 825                                 continue;
 826                         }
 827
 828                         start_bidx = start_bidx_of_node(nofs, inode);
 829                         data_page = get_read_data_page(inode,
 830                                         start_bidx + ofs_in_node, REQ_RAHEAD,
 831                                         true);
 832                         if (IS_ERR(data_page)) {
 833                                 iput(inode);
 834                                 continue;
 835                         }
 836
 837                         f2fs_put_page(data_page, 0);
 838                         add_gc_inode(gc_list, inode);
 839                         continue;
 840                 }
 841
 842                 /* phase 4 */
 843                 inode = find_gc_inode(gc_list, dni.ino);
 844                 if (inode) {
 845                         struct f2fs_inode_info *fi = F2FS_I(inode);
 846                         bool locked = false;
 847
 848                         if (S_ISREG(inode->i_mode)) {
 849                                 if (!down_write_trylock(&fi->dio_rwsem[READ]))
 850                                         continue;
 851                                 if (!down_write_trylock(
 852                                                 &fi->dio_rwsem[WRITE])) {
 853                                         up_write(&fi->dio_rwsem[READ]);
 854                                         continue;
 855                                 }
 856                                 locked = true;
 857                         }
 858
 859                         start_bidx = start_bidx_of_node(nofs, inode)
 860                                                                 + ofs_in_node;
 861                         if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
 862                                 move_encrypted_block(inode, start_bidx, segno, off);
 863                         else
 864                                 move_data_page(inode, start_bidx, gc_type, segno, off);
 865
 866                         if (locked) {
 867                                 up_write(&fi->dio_rwsem[WRITE]);
 868                                 up_write(&fi->dio_rwsem[READ]);
 869                         }
 870
 871                         stat_inc_data_blk_count(sbi, 1, gc_type);
 872                 }
 873         }
 874
 875         if (++phase < 5)
 876                 goto next_step;
 877 }
 878
 879 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 880                         int gc_type)
 881 {
 882         struct sit_info *sit_i = SIT_I(sbi);
 883         int ret;
 884
 885         mutex_lock(&sit_i->sentry_lock);
 886         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
 887                                               NO_CHECK_TYPE, LFS);
 888         mutex_unlock(&sit_i->sentry_lock);
 889         return ret;
 890 }
 891
 892 static int do_garbage_collect(struct f2fs_sb_info *sbi,
 893                                 unsigned int start_segno,
 894                                 struct gc_inode_list *gc_list, int gc_type)
 895 {
 896         struct page *sum_page;
 897         struct f2fs_summary_block *sum;
 898         struct blk_plug plug;
 899         unsigned int segno = start_segno;
 900         unsigned int end_segno = start_segno + sbi->segs_per_sec;
 901         int sec_freed = 0;
 902         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 903                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
 904
 905         /* readahead multi ssa blocks those have contiguous address */
 906         if (sbi->segs_per_sec > 1)
 907                 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
 908                                         sbi->segs_per_sec, META_SSA, true);
 909
 910         /* reference all summary page */
 911         while (segno < end_segno) {
 912                 sum_page = get_sum_page(sbi, segno++);
 913                 unlock_page(sum_page);
 914         }
 915
 916         blk_start_plug(&plug);
 917
 918         for (segno = start_segno; segno < end_segno; segno++) {
 919
 920                 /* find segment summary of victim */
 921                 sum_page = find_get_page(META_MAPPING(sbi),
 922                                         GET_SUM_BLOCK(sbi, segno));
 923                 f2fs_put_page(sum_page, 0);
 924
 925                 if (get_valid_blocks(sbi, segno, false) == 0 ||
 926                                 !PageUptodate(sum_page) ||
 927                                 unlikely(f2fs_cp_error(sbi)))
 928                         goto next;
 929
 930                 sum = page_address(sum_page);
 931                 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
 932
 933                 /*
 934                  * this is to avoid deadlock:
 935                  * - lock_page(sum_page)         - f2fs_replace_block
 936                  *  - check_valid_map()            - mutex_lock(sentry_lock)
 937                  *   - mutex_lock(sentry_lock)     - change_curseg()
 938                  *                                  - lock_page(sum_page)
 939                  */
 940                 if (type == SUM_TYPE_NODE)
 941                         gc_node_segment(sbi, sum->entries, segno, gc_type);
 942                 else
 943                         gc_data_segment(sbi, sum->entries, gc_list, segno,
 944                                                                 gc_type);
 945
 946                 stat_inc_seg_count(sbi, type, gc_type);
 947 next:
 948                 f2fs_put_page(sum_page, 0);
 949         }
 950
 951         if (gc_type == FG_GC)
 952                 f2fs_submit_merged_write(sbi,
 953                                 (type == SUM_TYPE_NODE) ? NODE : DATA);
 954
 955         blk_finish_plug(&plug);
 956
 957         if (gc_type == FG_GC &&
 958                 get_valid_blocks(sbi, start_segno, true) == 0)
 959                 sec_freed = 1;
 960
 961         stat_inc_call_count(sbi->stat_info);
 962
 963         return sec_freed;
 964 }
 965
 966 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 967                         bool background, unsigned int segno)
 968 {
 969         int gc_type = sync ? FG_GC : BG_GC;
 970         int sec_freed = 0;
 971         int ret;
 972         struct cp_control cpc;
 973         unsigned int init_segno = segno;
 974         struct gc_inode_list gc_list = {
 975                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
 976                 .iroot = RADIX_TREE_INIT(GFP_NOFS),
 977         };
 978
 979         cpc.reason = __get_cp_reason(sbi);
 980 gc_more:
 981         if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE))) {
 982                 ret = -EINVAL;
 983                 goto stop;
 984         }
 985         if (unlikely(f2fs_cp_error(sbi))) {
 986                 ret = -EIO;
 987                 goto stop;
 988         }
 989
 990         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
 991                 /*
 992                  * For example, if there are many prefree_segments below given
 993                  * threshold, we can make them free by checkpoint. Then, we
 994                  * secure free segments which doesn't need fggc any more.
 995                  */
 996                 if (prefree_segments(sbi)) {
 997                         ret = write_checkpoint(sbi, &cpc);
 998                         if (ret)
 999                                 goto stop;
1000                 }
1001                 if (has_not_enough_free_secs(sbi, 0, 0))
1002                         gc_type = FG_GC;
1003         }
1004
1005         ret = -EINVAL;
1006         /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1007         if (gc_type == BG_GC && !background)
1008                 goto stop;
1009         if (!__get_victim(sbi, &segno, gc_type))
1010                 goto stop;
1011         ret = 0;
1012
1013         if (do_garbage_collect(sbi, segno, &gc_list, gc_type) &&
1014                         gc_type == FG_GC)
1015                 sec_freed++;
1016
1017         if (gc_type == FG_GC)
1018                 sbi->cur_victim_sec = NULL_SEGNO;
1019
1020         if (!sync) {
1021                 if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1022                         segno = NULL_SEGNO;
1023                         goto gc_more;
1024                 }
1025
1026                 if (gc_type == FG_GC)
1027                         ret = write_checkpoint(sbi, &cpc);
1028         }
1029 stop:
1030         SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1031         SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1032         mutex_unlock(&sbi->gc_mutex);
1033
1034         put_gc_inode(&gc_list);
1035
1036         if (sync)
1037                 ret = sec_freed ? 0 : -EAGAIN;
1038         return ret;
1039 }
1040
1041 void build_gc_manager(struct f2fs_sb_info *sbi)
1042 {
1043         u64 main_count, resv_count, ovp_count;
1044
1045         DIRTY_I(sbi)->v_ops = &default_v_ops;
1046
1047         /* threshold of # of valid blocks in a section for victims of FG_GC */
1048         main_count = SM_I(sbi)->main_segments << sbi->log_blocks_per_seg;
1049         resv_count = SM_I(sbi)->reserved_segments << sbi->log_blocks_per_seg;
1050         ovp_count = SM_I(sbi)->ovp_segments << sbi->log_blocks_per_seg;
1051
1052         sbi->fggc_threshold = div64_u64((main_count - ovp_count) *
1053                                 BLKS_PER_SEC(sbi), (main_count - resv_count));
1054
1055         /* give warm/cold data area from slower device */
1056         if (sbi->s_ndevs && sbi->segs_per_sec == 1)
1057                 SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1058                                 GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1059 }