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         };
 604         struct dnode_of_data dn;
 605         struct f2fs_summary sum;
 606         struct node_info ni;
 607         struct page *page;
 608         block_t newaddr;
 609         int err;
 610
 611         /* do not read out */
 612         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 613         if (!page)
 614                 return;
 615
 616         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 617                 goto out;
 618
 619         if (f2fs_is_atomic_file(inode))
 620                 goto out;
 621
 622         set_new_dnode(&dn, inode, NULL, NULL, 0);
 623         err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
 624         if (err)
 625                 goto out;
 626
 627         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 628                 ClearPageUptodate(page);
 629                 goto put_out;
 630         }
 631
 632         /*
 633          * don't cache encrypted data into meta inode until previous dirty
 634          * data were writebacked to avoid racing between GC and flush.
 635          */
 636         f2fs_wait_on_page_writeback(page, DATA, true);
 637
 638         get_node_info(fio.sbi, dn.nid, &ni);
 639         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
 640
 641         /* read page */
 642         fio.page = page;
 643         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 644
 645         allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 646                                                         &sum, CURSEG_COLD_DATA);
 647
 648         fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
 649                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
 650         if (!fio.encrypted_page) {
 651                 err = -ENOMEM;
 652                 goto recover_block;
 653         }
 654
 655         err = f2fs_submit_page_bio(&fio);
 656         if (err)
 657                 goto put_page_out;
 658
 659         /* write page */
 660         lock_page(fio.encrypted_page);
 661
 662         if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
 663                 err = -EIO;
 664                 goto put_page_out;
 665         }
 666         if (unlikely(!PageUptodate(fio.encrypted_page))) {
 667                 err = -EIO;
 668                 goto put_page_out;
 669         }
 670
 671         set_page_dirty(fio.encrypted_page);
 672         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
 673         if (clear_page_dirty_for_io(fio.encrypted_page))
 674                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
 675
 676         set_page_writeback(fio.encrypted_page);
 677
 678         /* allocate block address */
 679         f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
 680
 681         fio.op = REQ_OP_WRITE;
 682         fio.op_flags = REQ_SYNC;
 683         fio.new_blkaddr = newaddr;
 684         f2fs_submit_page_write(&fio);
 685
 686         f2fs_update_data_blkaddr(&dn, newaddr);
 687         set_inode_flag(inode, FI_APPEND_WRITE);
 688         if (page->index == 0)
 689                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 690 put_page_out:
 691         f2fs_put_page(fio.encrypted_page, 1);
 692 recover_block:
 693         if (err)
 694                 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
 695                                                                 true, true);
 696 put_out:
 697         f2fs_put_dnode(&dn);
 698 out:
 699         f2fs_put_page(page, 1);
 700 }
 701
 702 static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
 703                                                         unsigned int segno, int off)
 704 {
 705         struct page *page;
 706
 707         page = get_lock_data_page(inode, bidx, true);
 708         if (IS_ERR(page))
 709                 return;
 710
 711         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 712                 goto out;
 713
 714         if (f2fs_is_atomic_file(inode))
 715                 goto out;
 716
 717         if (gc_type == BG_GC) {
 718                 if (PageWriteback(page))
 719                         goto out;
 720                 set_page_dirty(page);
 721                 set_cold_data(page);
 722         } else {
 723                 struct f2fs_io_info fio = {
 724                         .sbi = F2FS_I_SB(inode),
 725                         .type = DATA,
 726                         .temp = COLD,
 727                         .op = REQ_OP_WRITE,
 728                         .op_flags = REQ_SYNC,
 729                         .old_blkaddr = NULL_ADDR,
 730                         .page = page,
 731                         .encrypted_page = NULL,
 732                         .need_lock = LOCK_REQ,
 733                 };
 734                 bool is_dirty = PageDirty(page);
 735                 int err;
 736
 737 retry:
 738                 set_page_dirty(page);
 739                 f2fs_wait_on_page_writeback(page, DATA, true);
 740                 if (clear_page_dirty_for_io(page)) {
 741                         inode_dec_dirty_pages(inode);
 742                         remove_dirty_inode(inode);
 743                 }
 744
 745                 set_cold_data(page);
 746
 747                 err = do_write_data_page(&fio);
 748                 if (err == -ENOMEM && is_dirty) {
 749                         congestion_wait(BLK_RW_ASYNC, HZ/50);
 750                         goto retry;
 751                 }
 752         }
 753 out:
 754         f2fs_put_page(page, 1);
 755 }
 756
 757 /*
 758  * This function tries to get parent node of victim data block, and identifies
 759  * data block validity. If the block is valid, copy that with cold status and
 760  * modify parent node.
 761  * If the parent node is not valid or the data block address is different,
 762  * the victim data block is ignored.
 763  */
 764 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 765                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 766 {
 767         struct super_block *sb = sbi->sb;
 768         struct f2fs_summary *entry;
 769         block_t start_addr;
 770         int off;
 771         int phase = 0;
 772
 773         start_addr = START_BLOCK(sbi, segno);
 774
 775 next_step:
 776         entry = sum;
 777
 778         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 779                 struct page *data_page;
 780                 struct inode *inode;
 781                 struct node_info dni; /* dnode info for the data */
 782                 unsigned int ofs_in_node, nofs;
 783                 block_t start_bidx;
 784                 nid_t nid = le32_to_cpu(entry->nid);
 785
 786                 /* stop BG_GC if there is not enough free sections. */
 787                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 788                         return;
 789
 790                 if (check_valid_map(sbi, segno, off) == 0)
 791                         continue;
 792
 793                 if (phase == 0) {
 794                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 795                                                         META_NAT, true);
 796                         continue;
 797                 }
 798
 799                 if (phase == 1) {
 800                         ra_node_page(sbi, nid);
 801                         continue;
 802                 }
 803
 804                 /* Get an inode by ino with checking validity */
 805                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
 806                         continue;
 807
 808                 if (phase == 2) {
 809                         ra_node_page(sbi, dni.ino);
 810                         continue;
 811                 }
 812
 813                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 814
 815                 if (phase == 3) {
 816                         inode = f2fs_iget(sb, dni.ino);
 817                         if (IS_ERR(inode) || is_bad_inode(inode))
 818                                 continue;
 819
 820                         /* if encrypted inode, let's go phase 3 */
 821                         if (f2fs_encrypted_inode(inode) &&
 822                                                 S_ISREG(inode->i_mode)) {
 823                                 add_gc_inode(gc_list, inode);
 824                                 continue;
 825                         }
 826
 827                         start_bidx = start_bidx_of_node(nofs, inode);
 828                         data_page = get_read_data_page(inode,
 829                                         start_bidx + ofs_in_node, REQ_RAHEAD,
 830                                         true);
 831                         if (IS_ERR(data_page)) {
 832                                 iput(inode);
 833                                 continue;
 834                         }
 835
 836                         f2fs_put_page(data_page, 0);
 837                         add_gc_inode(gc_list, inode);
 838                         continue;
 839                 }
 840
 841                 /* phase 4 */
 842                 inode = find_gc_inode(gc_list, dni.ino);
 843                 if (inode) {
 844                         struct f2fs_inode_info *fi = F2FS_I(inode);
 845                         bool locked = false;
 846
 847                         if (S_ISREG(inode->i_mode)) {
 848                                 if (!down_write_trylock(&fi->dio_rwsem[READ]))
 849                                         continue;
 850                                 if (!down_write_trylock(
 851                                                 &fi->dio_rwsem[WRITE])) {
 852                                         up_write(&fi->dio_rwsem[READ]);
 853                                         continue;
 854                                 }
 855                                 locked = true;
 856                         }
 857
 858                         start_bidx = start_bidx_of_node(nofs, inode)
 859                                                                 + ofs_in_node;
 860                         if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
 861                                 move_encrypted_block(inode, start_bidx, segno, off);
 862                         else
 863                                 move_data_page(inode, start_bidx, gc_type, segno, off);
 864
 865                         if (locked) {
 866                                 up_write(&fi->dio_rwsem[WRITE]);
 867                                 up_write(&fi->dio_rwsem[READ]);
 868                         }
 869
 870                         stat_inc_data_blk_count(sbi, 1, gc_type);
 871                 }
 872         }
 873
 874         if (++phase < 5)
 875                 goto next_step;
 876 }
 877
 878 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 879                         int gc_type)
 880 {
 881         struct sit_info *sit_i = SIT_I(sbi);
 882         int ret;
 883
 884         mutex_lock(&sit_i->sentry_lock);
 885         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
 886                                               NO_CHECK_TYPE, LFS);
 887         mutex_unlock(&sit_i->sentry_lock);
 888         return ret;
 889 }
 890
 891 static int do_garbage_collect(struct f2fs_sb_info *sbi,
 892                                 unsigned int start_segno,
 893                                 struct gc_inode_list *gc_list, int gc_type)
 894 {
 895         struct page *sum_page;
 896         struct f2fs_summary_block *sum;
 897         struct blk_plug plug;
 898         unsigned int segno = start_segno;
 899         unsigned int end_segno = start_segno + sbi->segs_per_sec;
 900         int sec_freed = 0;
 901         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 902                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
 903
 904         /* readahead multi ssa blocks those have contiguous address */
 905         if (sbi->segs_per_sec > 1)
 906                 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
 907                                         sbi->segs_per_sec, META_SSA, true);
 908
 909         /* reference all summary page */
 910         while (segno < end_segno) {
 911                 sum_page = get_sum_page(sbi, segno++);
 912                 unlock_page(sum_page);
 913         }
 914
 915         blk_start_plug(&plug);
 916
 917         for (segno = start_segno; segno < end_segno; segno++) {
 918
 919                 /* find segment summary of victim */
 920                 sum_page = find_get_page(META_MAPPING(sbi),
 921                                         GET_SUM_BLOCK(sbi, segno));
 922                 f2fs_put_page(sum_page, 0);
 923
 924                 if (get_valid_blocks(sbi, segno, false) == 0 ||
 925                                 !PageUptodate(sum_page) ||
 926                                 unlikely(f2fs_cp_error(sbi)))
 927                         goto next;
 928
 929                 sum = page_address(sum_page);
 930                 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
 931
 932                 /*
 933                  * this is to avoid deadlock:
 934                  * - lock_page(sum_page)         - f2fs_replace_block
 935                  *  - check_valid_map()            - mutex_lock(sentry_lock)
 936                  *   - mutex_lock(sentry_lock)     - change_curseg()
 937                  *                                  - lock_page(sum_page)
 938                  */
 939                 if (type == SUM_TYPE_NODE)
 940                         gc_node_segment(sbi, sum->entries, segno, gc_type);
 941                 else
 942                         gc_data_segment(sbi, sum->entries, gc_list, segno,
 943                                                                 gc_type);
 944
 945                 stat_inc_seg_count(sbi, type, gc_type);
 946 next:
 947                 f2fs_put_page(sum_page, 0);
 948         }
 949
 950         if (gc_type == FG_GC)
 951                 f2fs_submit_merged_write(sbi,
 952                                 (type == SUM_TYPE_NODE) ? NODE : DATA);
 953
 954         blk_finish_plug(&plug);
 955
 956         if (gc_type == FG_GC &&
 957                 get_valid_blocks(sbi, start_segno, true) == 0)
 958                 sec_freed = 1;
 959
 960         stat_inc_call_count(sbi->stat_info);
 961
 962         return sec_freed;
 963 }
 964
 965 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 966                         bool background, unsigned int segno)
 967 {
 968         int gc_type = sync ? FG_GC : BG_GC;
 969         int sec_freed = 0;
 970         int ret;
 971         struct cp_control cpc;
 972         unsigned int init_segno = segno;
 973         struct gc_inode_list gc_list = {
 974                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
 975                 .iroot = RADIX_TREE_INIT(GFP_NOFS),
 976         };
 977
 978         cpc.reason = __get_cp_reason(sbi);
 979 gc_more:
 980         if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE))) {
 981                 ret = -EINVAL;
 982                 goto stop;
 983         }
 984         if (unlikely(f2fs_cp_error(sbi))) {
 985                 ret = -EIO;
 986                 goto stop;
 987         }
 988
 989         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
 990                 /*
 991                  * For example, if there are many prefree_segments below given
 992                  * threshold, we can make them free by checkpoint. Then, we
 993                  * secure free segments which doesn't need fggc any more.
 994                  */
 995                 if (prefree_segments(sbi)) {
 996                         ret = write_checkpoint(sbi, &cpc);
 997                         if (ret)
 998                                 goto stop;
 999                 }
1000                 if (has_not_enough_free_secs(sbi, 0, 0))
1001                         gc_type = FG_GC;
1002         }
1003
1004         ret = -EINVAL;
1005         /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1006         if (gc_type == BG_GC && !background)
1007                 goto stop;
1008         if (!__get_victim(sbi, &segno, gc_type))
1009                 goto stop;
1010         ret = 0;
1011
1012         if (do_garbage_collect(sbi, segno, &gc_list, gc_type) &&
1013                         gc_type == FG_GC)
1014                 sec_freed++;
1015
1016         if (gc_type == FG_GC)
1017                 sbi->cur_victim_sec = NULL_SEGNO;
1018
1019         if (!sync) {
1020                 if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1021                         segno = NULL_SEGNO;
1022                         goto gc_more;
1023                 }
1024
1025                 if (gc_type == FG_GC)
1026                         ret = write_checkpoint(sbi, &cpc);
1027         }
1028 stop:
1029         SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1030         SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1031         mutex_unlock(&sbi->gc_mutex);
1032
1033         put_gc_inode(&gc_list);
1034
1035         if (sync)
1036                 ret = sec_freed ? 0 : -EAGAIN;
1037         return ret;
1038 }
1039
1040 void build_gc_manager(struct f2fs_sb_info *sbi)
1041 {
1042         u64 main_count, resv_count, ovp_count;
1043
1044         DIRTY_I(sbi)->v_ops = &default_v_ops;
1045
1046         /* threshold of # of valid blocks in a section for victims of FG_GC */
1047         main_count = SM_I(sbi)->main_segments << sbi->log_blocks_per_seg;
1048         resv_count = SM_I(sbi)->reserved_segments << sbi->log_blocks_per_seg;
1049         ovp_count = SM_I(sbi)->ovp_segments << sbi->log_blocks_per_seg;
1050
1051         sbi->fggc_threshold = div64_u64((main_count - ovp_count) *
1052                                 BLKS_PER_SEC(sbi), (main_count - resv_count));
1053
1054         /* give warm/cold data area from slower device */
1055         if (sbi->s_ndevs && sbi->segs_per_sec == 1)
1056                 SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1057                                 GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1058 }