fs/f2fs/gc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * fs/f2fs/gc.c
   4  *
   5  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   6  *             http://www.samsung.com/
   7  */
   8 #include <linux/fs.h>
   9 #include <linux/module.h>
  10 #include <linux/backing-dev.h>
  11 #include <linux/init.h>
  12 #include <linux/f2fs_fs.h>
  13 #include <linux/kthread.h>
  14 #include <linux/delay.h>
  15 #include <linux/freezer.h>
  16
  17 #include "f2fs.h"
  18 #include "node.h"
  19 #include "segment.h"
  20 #include "gc.h"
  21 #include <trace/events/f2fs.h>
  22
  23 static int gc_thread_func(void *data)
  24 {
  25         struct f2fs_sb_info *sbi = data;
  26         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
  27         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
  28         unsigned int wait_ms;
  29
  30         wait_ms = gc_th->min_sleep_time;
  31
  32         set_freezable();
  33         do {
  34                 wait_event_interruptible_timeout(*wq,
  35                                 kthread_should_stop() || freezing(current) ||
  36                                 gc_th->gc_wake,
  37                                 msecs_to_jiffies(wait_ms));
  38
  39                 /* give it a try one time */
  40                 if (gc_th->gc_wake)
  41                         gc_th->gc_wake = 0;
  42
  43                 if (try_to_freeze()) {
  44                         stat_other_skip_bggc_count(sbi);
  45                         continue;
  46                 }
  47                 if (kthread_should_stop())
  48                         break;
  49
  50                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
  51                         increase_sleep_time(gc_th, &wait_ms);
  52                         stat_other_skip_bggc_count(sbi);
  53                         continue;
  54                 }
  55
  56                 if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
  57                         f2fs_show_injection_info(FAULT_CHECKPOINT);
  58                         f2fs_stop_checkpoint(sbi, false);
  59                 }
  60
  61                 if (!sb_start_write_trylock(sbi->sb)) {
  62                         stat_other_skip_bggc_count(sbi);
  63                         continue;
  64                 }
  65
  66                 /*
  67                  * [GC triggering condition]
  68                  * 0. GC is not conducted currently.
  69                  * 1. There are enough dirty segments.
  70                  * 2. IO subsystem is idle by checking the # of writeback pages.
  71                  * 3. IO subsystem is idle by checking the # of requests in
  72                  *    bdev's request list.
  73                  *
  74                  * Note) We have to avoid triggering GCs frequently.
  75                  * Because it is possible that some segments can be
  76                  * invalidated soon after by user update or deletion.
  77                  * So, I'd like to wait some time to collect dirty segments.
  78                  */
  79                 if (sbi->gc_mode == GC_URGENT) {
  80                         wait_ms = gc_th->urgent_sleep_time;
  81                         mutex_lock(&sbi->gc_mutex);
  82                         goto do_gc;
  83                 }
  84
  85                 if (!mutex_trylock(&sbi->gc_mutex)) {
  86                         stat_other_skip_bggc_count(sbi);
  87                         goto next;
  88                 }
  89
  90                 if (!is_idle(sbi, GC_TIME)) {
  91                         increase_sleep_time(gc_th, &wait_ms);
  92                         mutex_unlock(&sbi->gc_mutex);
  93                         stat_io_skip_bggc_count(sbi);
  94                         goto next;
  95                 }
  96
  97                 if (has_enough_invalid_blocks(sbi))
  98                         decrease_sleep_time(gc_th, &wait_ms);
  99                 else
 100                         increase_sleep_time(gc_th, &wait_ms);
 101 do_gc:
 102                 stat_inc_bggc_count(sbi);
 103
 104                 /* if return value is not zero, no victim was selected */
 105                 if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC), true, NULL_SEGNO))
 106                         wait_ms = gc_th->no_gc_sleep_time;
 107
 108                 trace_f2fs_background_gc(sbi->sb, wait_ms,
 109                                 prefree_segments(sbi), free_segments(sbi));
 110
 111                 /* balancing f2fs's metadata periodically */
 112                 f2fs_balance_fs_bg(sbi);
 113 next:
 114                 sb_end_write(sbi->sb);
 115
 116         } while (!kthread_should_stop());
 117         return 0;
 118 }
 119
 120 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
 121 {
 122         struct f2fs_gc_kthread *gc_th;
 123         dev_t dev = sbi->sb->s_bdev->bd_dev;
 124         int err = 0;
 125
 126         gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
 127         if (!gc_th) {
 128                 err = -ENOMEM;
 129                 goto out;
 130         }
 131
 132         gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
 133         gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
 134         gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
 135         gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
 136
 137         gc_th->gc_wake= 0;
 138
 139         sbi->gc_thread = gc_th;
 140         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 141         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 142                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 143         if (IS_ERR(gc_th->f2fs_gc_task)) {
 144                 err = PTR_ERR(gc_th->f2fs_gc_task);
 145                 kvfree(gc_th);
 146                 sbi->gc_thread = NULL;
 147         }
 148 out:
 149         return err;
 150 }
 151
 152 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
 153 {
 154         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 155         if (!gc_th)
 156                 return;
 157         kthread_stop(gc_th->f2fs_gc_task);
 158         kvfree(gc_th);
 159         sbi->gc_thread = NULL;
 160 }
 161
 162 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
 163 {
 164         int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 165
 166         switch (sbi->gc_mode) {
 167         case GC_IDLE_CB:
 168                 gc_mode = GC_CB;
 169                 break;
 170         case GC_IDLE_GREEDY:
 171         case GC_URGENT:
 172                 gc_mode = GC_GREEDY;
 173                 break;
 174         }
 175         return gc_mode;
 176 }
 177
 178 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 179                         int type, struct victim_sel_policy *p)
 180 {
 181         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 182
 183         if (p->alloc_mode == SSR) {
 184                 p->gc_mode = GC_GREEDY;
 185                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 186                 p->max_search = dirty_i->nr_dirty[type];
 187                 p->ofs_unit = 1;
 188         } else {
 189                 p->gc_mode = select_gc_type(sbi, gc_type);
 190                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 191                 p->max_search = dirty_i->nr_dirty[DIRTY];
 192                 p->ofs_unit = sbi->segs_per_sec;
 193         }
 194
 195         /* we need to check every dirty segments in the FG_GC case */
 196         if (gc_type != FG_GC &&
 197                         (sbi->gc_mode != GC_URGENT) &&
 198                         p->max_search > sbi->max_victim_search)
 199                 p->max_search = sbi->max_victim_search;
 200
 201         /* let's select beginning hot/small space first in no_heap mode*/
 202         if (test_opt(sbi, NOHEAP) &&
 203                 (type == CURSEG_HOT_DATA || IS_NODESEG(type)))
 204                 p->offset = 0;
 205         else
 206                 p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
 207 }
 208
 209 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 210                                 struct victim_sel_policy *p)
 211 {
 212         /* SSR allocates in a segment unit */
 213         if (p->alloc_mode == SSR)
 214                 return sbi->blocks_per_seg;
 215         if (p->gc_mode == GC_GREEDY)
 216                 return 2 * sbi->blocks_per_seg * p->ofs_unit;
 217         else if (p->gc_mode == GC_CB)
 218                 return UINT_MAX;
 219         else /* No other gc_mode */
 220                 return 0;
 221 }
 222
 223 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 224 {
 225         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 226         unsigned int secno;
 227
 228         /*
 229          * If the gc_type is FG_GC, we can select victim segments
 230          * selected by background GC before.
 231          * Those segments guarantee they have small valid blocks.
 232          */
 233         for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
 234                 if (sec_usage_check(sbi, secno))
 235                         continue;
 236                 clear_bit(secno, dirty_i->victim_secmap);
 237                 return GET_SEG_FROM_SEC(sbi, secno);
 238         }
 239         return NULL_SEGNO;
 240 }
 241
 242 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 243 {
 244         struct sit_info *sit_i = SIT_I(sbi);
 245         unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
 246         unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
 247         unsigned long long mtime = 0;
 248         unsigned int vblocks;
 249         unsigned char age = 0;
 250         unsigned char u;
 251         unsigned int i;
 252
 253         for (i = 0; i < sbi->segs_per_sec; i++)
 254                 mtime += get_seg_entry(sbi, start + i)->mtime;
 255         vblocks = get_valid_blocks(sbi, segno, true);
 256
 257         mtime = div_u64(mtime, sbi->segs_per_sec);
 258         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 259
 260         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 261
 262         /* Handle if the system time has changed by the user */
 263         if (mtime < sit_i->min_mtime)
 264                 sit_i->min_mtime = mtime;
 265         if (mtime > sit_i->max_mtime)
 266                 sit_i->max_mtime = mtime;
 267         if (sit_i->max_mtime != sit_i->min_mtime)
 268                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 269                                 sit_i->max_mtime - sit_i->min_mtime);
 270
 271         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 272 }
 273
 274 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 275                         unsigned int segno, struct victim_sel_policy *p)
 276 {
 277         if (p->alloc_mode == SSR)
 278                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 279
 280         /* alloc_mode == LFS */
 281         if (p->gc_mode == GC_GREEDY)
 282                 return get_valid_blocks(sbi, segno, true);
 283         else
 284                 return get_cb_cost(sbi, segno);
 285 }
 286
 287 static unsigned int count_bits(const unsigned long *addr,
 288                                 unsigned int offset, unsigned int len)
 289 {
 290         unsigned int end = offset + len, sum = 0;
 291
 292         while (offset < end) {
 293                 if (test_bit(offset++, addr))
 294                         ++sum;
 295         }
 296         return sum;
 297 }
 298
 299 /*
 300  * This function is called from two paths.
 301  * One is garbage collection and the other is SSR segment selection.
 302  * When it is called during GC, it just gets a victim segment
 303  * and it does not remove it from dirty seglist.
 304  * When it is called from SSR segment selection, it finds a segment
 305  * which has minimum valid blocks and removes it from dirty seglist.
 306  */
 307 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 308                 unsigned int *result, int gc_type, int type, char alloc_mode)
 309 {
 310         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 311         struct sit_info *sm = SIT_I(sbi);
 312         struct victim_sel_policy p;
 313         unsigned int secno, last_victim;
 314         unsigned int last_segment;
 315         unsigned int nsearched = 0;
 316
 317         mutex_lock(&dirty_i->seglist_lock);
 318         last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
 319
 320         p.alloc_mode = alloc_mode;
 321         select_policy(sbi, gc_type, type, &p);
 322
 323         p.min_segno = NULL_SEGNO;
 324         p.min_cost = get_max_cost(sbi, &p);
 325
 326         if (*result != NULL_SEGNO) {
 327                 if (get_valid_blocks(sbi, *result, false) &&
 328                         !sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
 329                         p.min_segno = *result;
 330                 goto out;
 331         }
 332
 333         if (p.max_search == 0)
 334                 goto out;
 335
 336         if (__is_large_section(sbi) && p.alloc_mode == LFS) {
 337                 if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
 338                         p.min_segno = sbi->next_victim_seg[BG_GC];
 339                         *result = p.min_segno;
 340                         sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
 341                         goto got_result;
 342                 }
 343                 if (gc_type == FG_GC &&
 344                                 sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
 345                         p.min_segno = sbi->next_victim_seg[FG_GC];
 346                         *result = p.min_segno;
 347                         sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
 348                         goto got_result;
 349                 }
 350         }
 351
 352         last_victim = sm->last_victim[p.gc_mode];
 353         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 354                 p.min_segno = check_bg_victims(sbi);
 355                 if (p.min_segno != NULL_SEGNO)
 356                         goto got_it;
 357         }
 358
 359         while (1) {
 360                 unsigned long cost;
 361                 unsigned int segno;
 362
 363                 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
 364                 if (segno >= last_segment) {
 365                         if (sm->last_victim[p.gc_mode]) {
 366                                 last_segment =
 367                                         sm->last_victim[p.gc_mode];
 368                                 sm->last_victim[p.gc_mode] = 0;
 369                                 p.offset = 0;
 370                                 continue;
 371                         }
 372                         break;
 373                 }
 374
 375                 p.offset = segno + p.ofs_unit;
 376                 if (p.ofs_unit > 1) {
 377                         p.offset -= segno % p.ofs_unit;
 378                         nsearched += count_bits(p.dirty_segmap,
 379                                                 p.offset - p.ofs_unit,
 380                                                 p.ofs_unit);
 381                 } else {
 382                         nsearched++;
 383                 }
 384
 385                 secno = GET_SEC_FROM_SEG(sbi, segno);
 386
 387                 if (sec_usage_check(sbi, secno))
 388                         goto next;
 389                 /* Don't touch checkpointed data */
 390                 if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
 391                                         get_ckpt_valid_blocks(sbi, segno) &&
 392                                         p.alloc_mode != SSR))
 393                         goto next;
 394                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 395                         goto next;
 396
 397                 cost = get_gc_cost(sbi, segno, &p);
 398
 399                 if (p.min_cost > cost) {
 400                         p.min_segno = segno;
 401                         p.min_cost = cost;
 402                 }
 403 next:
 404                 if (nsearched >= p.max_search) {
 405                         if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
 406                                 sm->last_victim[p.gc_mode] = last_victim + 1;
 407                         else
 408                                 sm->last_victim[p.gc_mode] = segno + 1;
 409                         sm->last_victim[p.gc_mode] %=
 410                                 (MAIN_SECS(sbi) * sbi->segs_per_sec);
 411                         break;
 412                 }
 413         }
 414         if (p.min_segno != NULL_SEGNO) {
 415 got_it:
 416                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 417 got_result:
 418                 if (p.alloc_mode == LFS) {
 419                         secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
 420                         if (gc_type == FG_GC)
 421                                 sbi->cur_victim_sec = secno;
 422                         else
 423                                 set_bit(secno, dirty_i->victim_secmap);
 424                 }
 425
 426         }
 427 out:
 428         if (p.min_segno != NULL_SEGNO)
 429                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 430                                 sbi->cur_victim_sec,
 431                                 prefree_segments(sbi), free_segments(sbi));
 432         mutex_unlock(&dirty_i->seglist_lock);
 433
 434         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 435 }
 436
 437 static const struct victim_selection default_v_ops = {
 438         .get_victim = get_victim_by_default,
 439 };
 440
 441 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 442 {
 443         struct inode_entry *ie;
 444
 445         ie = radix_tree_lookup(&gc_list->iroot, ino);
 446         if (ie)
 447                 return ie->inode;
 448         return NULL;
 449 }
 450
 451 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 452 {
 453         struct inode_entry *new_ie;
 454
 455         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
 456                 iput(inode);
 457                 return;
 458         }
 459         new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab, GFP_NOFS);
 460         new_ie->inode = inode;
 461
 462         f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
 463         list_add_tail(&new_ie->list, &gc_list->ilist);
 464 }
 465
 466 static void put_gc_inode(struct gc_inode_list *gc_list)
 467 {
 468         struct inode_entry *ie, *next_ie;
 469         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
 470                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
 471                 iput(ie->inode);
 472                 list_del(&ie->list);
 473                 kmem_cache_free(f2fs_inode_entry_slab, ie);
 474         }
 475 }
 476
 477 static int check_valid_map(struct f2fs_sb_info *sbi,
 478                                 unsigned int segno, int offset)
 479 {
 480         struct sit_info *sit_i = SIT_I(sbi);
 481         struct seg_entry *sentry;
 482         int ret;
 483
 484         down_read(&sit_i->sentry_lock);
 485         sentry = get_seg_entry(sbi, segno);
 486         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 487         up_read(&sit_i->sentry_lock);
 488         return ret;
 489 }
 490
 491 /*
 492  * This function compares node address got in summary with that in NAT.
 493  * On validity, copy that node with cold status, otherwise (invalid node)
 494  * ignore that.
 495  */
 496 static int gc_node_segment(struct f2fs_sb_info *sbi,
 497                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 498 {
 499         struct f2fs_summary *entry;
 500         block_t start_addr;
 501         int off;
 502         int phase = 0;
 503         bool fggc = (gc_type == FG_GC);
 504         int submitted = 0;
 505
 506         start_addr = START_BLOCK(sbi, segno);
 507
 508 next_step:
 509         entry = sum;
 510
 511         if (fggc && phase == 2)
 512                 atomic_inc(&sbi->wb_sync_req[NODE]);
 513
 514         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 515                 nid_t nid = le32_to_cpu(entry->nid);
 516                 struct page *node_page;
 517                 struct node_info ni;
 518                 int err;
 519
 520                 /* stop BG_GC if there is not enough free sections. */
 521                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 522                         return submitted;
 523
 524                 if (check_valid_map(sbi, segno, off) == 0)
 525                         continue;
 526
 527                 if (phase == 0) {
 528                         f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 529                                                         META_NAT, true);
 530                         continue;
 531                 }
 532
 533                 if (phase == 1) {
 534                         f2fs_ra_node_page(sbi, nid);
 535                         continue;
 536                 }
 537
 538                 /* phase == 2 */
 539                 node_page = f2fs_get_node_page(sbi, nid);
 540                 if (IS_ERR(node_page))
 541                         continue;
 542
 543                 /* block may become invalid during f2fs_get_node_page */
 544                 if (check_valid_map(sbi, segno, off) == 0) {
 545                         f2fs_put_page(node_page, 1);
 546                         continue;
 547                 }
 548
 549                 if (f2fs_get_node_info(sbi, nid, &ni)) {
 550                         f2fs_put_page(node_page, 1);
 551                         continue;
 552                 }
 553
 554                 if (ni.blk_addr != start_addr + off) {
 555                         f2fs_put_page(node_page, 1);
 556                         continue;
 557                 }
 558
 559                 err = f2fs_move_node_page(node_page, gc_type);
 560                 if (!err && gc_type == FG_GC)
 561                         submitted++;
 562                 stat_inc_node_blk_count(sbi, 1, gc_type);
 563         }
 564
 565         if (++phase < 3)
 566                 goto next_step;
 567
 568         if (fggc)
 569                 atomic_dec(&sbi->wb_sync_req[NODE]);
 570         return submitted;
 571 }
 572
 573 /*
 574  * Calculate start block index indicating the given node offset.
 575  * Be careful, caller should give this node offset only indicating direct node
 576  * blocks. If any node offsets, which point the other types of node blocks such
 577  * as indirect or double indirect node blocks, are given, it must be a caller's
 578  * bug.
 579  */
 580 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
 581 {
 582         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 583         unsigned int bidx;
 584
 585         if (node_ofs == 0)
 586                 return 0;
 587
 588         if (node_ofs <= 2) {
 589                 bidx = node_ofs - 1;
 590         } else if (node_ofs <= indirect_blks) {
 591                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 592                 bidx = node_ofs - 2 - dec;
 593         } else {
 594                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 595                 bidx = node_ofs - 5 - dec;
 596         }
 597         return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
 598 }
 599
 600 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 601                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 602 {
 603         struct page *node_page;
 604         nid_t nid;
 605         unsigned int ofs_in_node;
 606         block_t source_blkaddr;
 607
 608         nid = le32_to_cpu(sum->nid);
 609         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 610
 611         node_page = f2fs_get_node_page(sbi, nid);
 612         if (IS_ERR(node_page))
 613                 return false;
 614
 615         if (f2fs_get_node_info(sbi, nid, dni)) {
 616                 f2fs_put_page(node_page, 1);
 617                 return false;
 618         }
 619
 620         if (sum->version != dni->version) {
 621                 f2fs_warn(sbi, "%s: valid data with mismatched node version.",
 622                           __func__);
 623                 set_sbi_flag(sbi, SBI_NEED_FSCK);
 624         }
 625
 626         *nofs = ofs_of_node(node_page);
 627         source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
 628         f2fs_put_page(node_page, 1);
 629
 630         if (source_blkaddr != blkaddr)
 631                 return false;
 632         return true;
 633 }
 634
 635 static int ra_data_block(struct inode *inode, pgoff_t index)
 636 {
 637         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 638         struct address_space *mapping = inode->i_mapping;
 639         struct dnode_of_data dn;
 640         struct page *page;
 641         struct extent_info ei = {0, 0, 0};
 642         struct f2fs_io_info fio = {
 643                 .sbi = sbi,
 644                 .ino = inode->i_ino,
 645                 .type = DATA,
 646                 .temp = COLD,
 647                 .op = REQ_OP_READ,
 648                 .op_flags = 0,
 649                 .encrypted_page = NULL,
 650                 .in_list = false,
 651                 .retry = false,
 652         };
 653         int err;
 654
 655         page = f2fs_grab_cache_page(mapping, index, true);
 656         if (!page)
 657                 return -ENOMEM;
 658
 659         if (f2fs_lookup_extent_cache(inode, index, &ei)) {
 660                 dn.data_blkaddr = ei.blk + index - ei.fofs;
 661                 if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
 662                                                 DATA_GENERIC_ENHANCE_READ))) {
 663                         err = -EFSCORRUPTED;
 664                         goto put_page;
 665                 }
 666                 goto got_it;
 667         }
 668
 669         set_new_dnode(&dn, inode, NULL, NULL, 0);
 670         err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
 671         if (err)
 672                 goto put_page;
 673         f2fs_put_dnode(&dn);
 674
 675         if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
 676                 err = -ENOENT;
 677                 goto put_page;
 678         }
 679         if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
 680                                                 DATA_GENERIC_ENHANCE))) {
 681                 err = -EFSCORRUPTED;
 682                 goto put_page;
 683         }
 684 got_it:
 685         /* read page */
 686         fio.page = page;
 687         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 688
 689         /*
 690          * don't cache encrypted data into meta inode until previous dirty
 691          * data were writebacked to avoid racing between GC and flush.
 692          */
 693         f2fs_wait_on_page_writeback(page, DATA, true, true);
 694
 695         f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
 696
 697         fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
 698                                         dn.data_blkaddr,
 699                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
 700         if (!fio.encrypted_page) {
 701                 err = -ENOMEM;
 702                 goto put_page;
 703         }
 704
 705         err = f2fs_submit_page_bio(&fio);
 706         if (err)
 707                 goto put_encrypted_page;
 708         f2fs_put_page(fio.encrypted_page, 0);
 709         f2fs_put_page(page, 1);
 710         return 0;
 711 put_encrypted_page:
 712         f2fs_put_page(fio.encrypted_page, 1);
 713 put_page:
 714         f2fs_put_page(page, 1);
 715         return err;
 716 }
 717
 718 /*
 719  * Move data block via META_MAPPING while keeping locked data page.
 720  * This can be used to move blocks, aka LBAs, directly on disk.
 721  */
 722 static int move_data_block(struct inode *inode, block_t bidx,
 723                                 int gc_type, unsigned int segno, int off)
 724 {
 725         struct f2fs_io_info fio = {
 726                 .sbi = F2FS_I_SB(inode),
 727                 .ino = inode->i_ino,
 728                 .type = DATA,
 729                 .temp = COLD,
 730                 .op = REQ_OP_READ,
 731                 .op_flags = 0,
 732                 .encrypted_page = NULL,
 733                 .in_list = false,
 734                 .retry = false,
 735         };
 736         struct dnode_of_data dn;
 737         struct f2fs_summary sum;
 738         struct node_info ni;
 739         struct page *page, *mpage;
 740         block_t newaddr;
 741         int err = 0;
 742         bool lfs_mode = test_opt(fio.sbi, LFS);
 743
 744         /* do not read out */
 745         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 746         if (!page)
 747                 return -ENOMEM;
 748
 749         if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
 750                 err = -ENOENT;
 751                 goto out;
 752         }
 753
 754         if (f2fs_is_atomic_file(inode)) {
 755                 F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
 756                 F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
 757                 err = -EAGAIN;
 758                 goto out;
 759         }
 760
 761         if (f2fs_is_pinned_file(inode)) {
 762                 f2fs_pin_file_control(inode, true);
 763                 err = -EAGAIN;
 764                 goto out;
 765         }
 766
 767         set_new_dnode(&dn, inode, NULL, NULL, 0);
 768         err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
 769         if (err)
 770                 goto out;
 771
 772         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 773                 ClearPageUptodate(page);
 774                 err = -ENOENT;
 775                 goto put_out;
 776         }
 777
 778         /*
 779          * don't cache encrypted data into meta inode until previous dirty
 780          * data were writebacked to avoid racing between GC and flush.
 781          */
 782         f2fs_wait_on_page_writeback(page, DATA, true, true);
 783
 784         f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
 785
 786         err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
 787         if (err)
 788                 goto put_out;
 789
 790         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
 791
 792         /* read page */
 793         fio.page = page;
 794         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 795
 796         if (lfs_mode)
 797                 down_write(&fio.sbi->io_order_lock);
 798
 799         mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
 800                                         fio.old_blkaddr, false);
 801         if (!mpage)
 802                 goto up_out;
 803
 804         fio.encrypted_page = mpage;
 805
 806         /* read source block in mpage */
 807         if (!PageUptodate(mpage)) {
 808                 err = f2fs_submit_page_bio(&fio);
 809                 if (err) {
 810                         f2fs_put_page(mpage, 1);
 811                         goto up_out;
 812                 }
 813                 lock_page(mpage);
 814                 if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
 815                                                 !PageUptodate(mpage))) {
 816                         err = -EIO;
 817                         f2fs_put_page(mpage, 1);
 818                         goto up_out;
 819                 }
 820         }
 821
 822         f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 823                                         &sum, CURSEG_COLD_DATA, NULL, false);
 824
 825         fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
 826                                 newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
 827         if (!fio.encrypted_page) {
 828                 err = -ENOMEM;
 829                 f2fs_put_page(mpage, 1);
 830                 goto recover_block;
 831         }
 832
 833         /* write target block */
 834         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
 835         memcpy(page_address(fio.encrypted_page),
 836                                 page_address(mpage), PAGE_SIZE);
 837         f2fs_put_page(mpage, 1);
 838         invalidate_mapping_pages(META_MAPPING(fio.sbi),
 839                                 fio.old_blkaddr, fio.old_blkaddr);
 840
 841         set_page_dirty(fio.encrypted_page);
 842         if (clear_page_dirty_for_io(fio.encrypted_page))
 843                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
 844
 845         set_page_writeback(fio.encrypted_page);
 846         ClearPageError(page);
 847
 848         /* allocate block address */
 849         f2fs_wait_on_page_writeback(dn.node_page, NODE, true, true);
 850
 851         fio.op = REQ_OP_WRITE;
 852         fio.op_flags = REQ_SYNC;
 853         fio.new_blkaddr = newaddr;
 854         f2fs_submit_page_write(&fio);
 855         if (fio.retry) {
 856                 err = -EAGAIN;
 857                 if (PageWriteback(fio.encrypted_page))
 858                         end_page_writeback(fio.encrypted_page);
 859                 goto put_page_out;
 860         }
 861
 862         f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
 863
 864         f2fs_update_data_blkaddr(&dn, newaddr);
 865         set_inode_flag(inode, FI_APPEND_WRITE);
 866         if (page->index == 0)
 867                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 868 put_page_out:
 869         f2fs_put_page(fio.encrypted_page, 1);
 870 recover_block:
 871         if (err)
 872                 f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
 873                                                                 true, true);
 874 up_out:
 875         if (lfs_mode)
 876                 up_write(&fio.sbi->io_order_lock);
 877 put_out:
 878         f2fs_put_dnode(&dn);
 879 out:
 880         f2fs_put_page(page, 1);
 881         return err;
 882 }
 883
 884 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
 885                                                         unsigned int segno, int off)
 886 {
 887         struct page *page;
 888         int err = 0;
 889
 890         page = f2fs_get_lock_data_page(inode, bidx, true);
 891         if (IS_ERR(page))
 892                 return PTR_ERR(page);
 893
 894         if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
 895                 err = -ENOENT;
 896                 goto out;
 897         }
 898
 899         if (f2fs_is_atomic_file(inode)) {
 900                 F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
 901                 F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
 902                 err = -EAGAIN;
 903                 goto out;
 904         }
 905         if (f2fs_is_pinned_file(inode)) {
 906                 if (gc_type == FG_GC)
 907                         f2fs_pin_file_control(inode, true);
 908                 err = -EAGAIN;
 909                 goto out;
 910         }
 911
 912         if (gc_type == BG_GC) {
 913                 if (PageWriteback(page)) {
 914                         err = -EAGAIN;
 915                         goto out;
 916                 }
 917                 set_page_dirty(page);
 918                 set_cold_data(page);
 919         } else {
 920                 struct f2fs_io_info fio = {
 921                         .sbi = F2FS_I_SB(inode),
 922                         .ino = inode->i_ino,
 923                         .type = DATA,
 924                         .temp = COLD,
 925                         .op = REQ_OP_WRITE,
 926                         .op_flags = REQ_SYNC,
 927                         .old_blkaddr = NULL_ADDR,
 928                         .page = page,
 929                         .encrypted_page = NULL,
 930                         .need_lock = LOCK_REQ,
 931                         .io_type = FS_GC_DATA_IO,
 932                 };
 933                 bool is_dirty = PageDirty(page);
 934
 935 retry:
 936                 f2fs_wait_on_page_writeback(page, DATA, true, true);
 937
 938                 set_page_dirty(page);
 939                 if (clear_page_dirty_for_io(page)) {
 940                         inode_dec_dirty_pages(inode);
 941                         f2fs_remove_dirty_inode(inode);
 942                 }
 943
 944                 set_cold_data(page);
 945
 946                 err = f2fs_do_write_data_page(&fio);
 947                 if (err) {
 948                         clear_cold_data(page);
 949                         if (err == -ENOMEM) {
 950                                 congestion_wait(BLK_RW_ASYNC, HZ/50);
 951                                 goto retry;
 952                         }
 953                         if (is_dirty)
 954                                 set_page_dirty(page);
 955                 }
 956         }
 957 out:
 958         f2fs_put_page(page, 1);
 959         return err;
 960 }
 961
 962 /*
 963  * This function tries to get parent node of victim data block, and identifies
 964  * data block validity. If the block is valid, copy that with cold status and
 965  * modify parent node.
 966  * If the parent node is not valid or the data block address is different,
 967  * the victim data block is ignored.
 968  */
 969 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 970                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 971 {
 972         struct super_block *sb = sbi->sb;
 973         struct f2fs_summary *entry;
 974         block_t start_addr;
 975         int off;
 976         int phase = 0;
 977         int submitted = 0;
 978
 979         start_addr = START_BLOCK(sbi, segno);
 980
 981 next_step:
 982         entry = sum;
 983
 984         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 985                 struct page *data_page;
 986                 struct inode *inode;
 987                 struct node_info dni; /* dnode info for the data */
 988                 unsigned int ofs_in_node, nofs;
 989                 block_t start_bidx;
 990                 nid_t nid = le32_to_cpu(entry->nid);
 991
 992                 /* stop BG_GC if there is not enough free sections. */
 993                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 994                         return submitted;
 995
 996                 if (check_valid_map(sbi, segno, off) == 0)
 997                         continue;
 998
 999                 if (phase == 0) {
1000                         f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1001                                                         META_NAT, true);
1002                         continue;
1003                 }
1004
1005                 if (phase == 1) {
1006                         f2fs_ra_node_page(sbi, nid);
1007                         continue;
1008                 }
1009
1010                 /* Get an inode by ino with checking validity */
1011                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1012                         continue;
1013
1014                 if (phase == 2) {
1015                         f2fs_ra_node_page(sbi, dni.ino);
1016                         continue;
1017                 }
1018
1019                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1020
1021                 if (phase == 3) {
1022                         inode = f2fs_iget(sb, dni.ino);
1023                         if (IS_ERR(inode) || is_bad_inode(inode))
1024                                 continue;
1025
1026                         if (!down_write_trylock(
1027                                 &F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1028                                 iput(inode);
1029                                 sbi->skipped_gc_rwsem++;
1030                                 continue;
1031                         }
1032
1033                         start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1034                                                                 ofs_in_node;
1035
1036                         if (f2fs_post_read_required(inode)) {
1037                                 int err = ra_data_block(inode, start_bidx);
1038
1039                                 up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1040                                 if (err) {
1041                                         iput(inode);
1042                                         continue;
1043                                 }
1044                                 add_gc_inode(gc_list, inode);
1045                                 continue;
1046                         }
1047
1048                         data_page = f2fs_get_read_data_page(inode,
1049                                                 start_bidx, REQ_RAHEAD, true);
1050                         up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1051                         if (IS_ERR(data_page)) {
1052                                 iput(inode);
1053                                 continue;
1054                         }
1055
1056                         f2fs_put_page(data_page, 0);
1057                         add_gc_inode(gc_list, inode);
1058                         continue;
1059                 }
1060
1061                 /* phase 4 */
1062                 inode = find_gc_inode(gc_list, dni.ino);
1063                 if (inode) {
1064                         struct f2fs_inode_info *fi = F2FS_I(inode);
1065                         bool locked = false;
1066                         int err;
1067
1068                         if (S_ISREG(inode->i_mode)) {
1069                                 if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
1070                                         continue;
1071                                 if (!down_write_trylock(
1072                                                 &fi->i_gc_rwsem[WRITE])) {
1073                                         sbi->skipped_gc_rwsem++;
1074                                         up_write(&fi->i_gc_rwsem[READ]);
1075                                         continue;
1076                                 }
1077                                 locked = true;
1078
1079                                 /* wait for all inflight aio data */
1080                                 inode_dio_wait(inode);
1081                         }
1082
1083                         start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1084                                                                 + ofs_in_node;
1085                         if (f2fs_post_read_required(inode))
1086                                 err = move_data_block(inode, start_bidx,
1087                                                         gc_type, segno, off);
1088                         else
1089                                 err = move_data_page(inode, start_bidx, gc_type,
1090                                                                 segno, off);
1091
1092                         if (!err && (gc_type == FG_GC ||
1093                                         f2fs_post_read_required(inode)))
1094                                 submitted++;
1095
1096                         if (locked) {
1097                                 up_write(&fi->i_gc_rwsem[WRITE]);
1098                                 up_write(&fi->i_gc_rwsem[READ]);
1099                         }
1100
1101                         stat_inc_data_blk_count(sbi, 1, gc_type);
1102                 }
1103         }
1104
1105         if (++phase < 5)
1106                 goto next_step;
1107
1108         return submitted;
1109 }
1110
1111 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1112                         int gc_type)
1113 {
1114         struct sit_info *sit_i = SIT_I(sbi);
1115         int ret;
1116
1117         down_write(&sit_i->sentry_lock);
1118         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1119                                               NO_CHECK_TYPE, LFS);
1120         up_write(&sit_i->sentry_lock);
1121         return ret;
1122 }
1123
1124 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1125                                 unsigned int start_segno,
1126                                 struct gc_inode_list *gc_list, int gc_type)
1127 {
1128         struct page *sum_page;
1129         struct f2fs_summary_block *sum;
1130         struct blk_plug plug;
1131         unsigned int segno = start_segno;
1132         unsigned int end_segno = start_segno + sbi->segs_per_sec;
1133         int seg_freed = 0, migrated = 0;
1134         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1135                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
1136         int submitted = 0;
1137
1138         if (__is_large_section(sbi))
1139                 end_segno = rounddown(end_segno, sbi->segs_per_sec);
1140
1141         /* readahead multi ssa blocks those have contiguous address */
1142         if (__is_large_section(sbi))
1143                 f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1144                                         end_segno - segno, META_SSA, true);
1145
1146         /* reference all summary page */
1147         while (segno < end_segno) {
1148                 sum_page = f2fs_get_sum_page(sbi, segno++);
1149                 if (IS_ERR(sum_page)) {
1150                         int err = PTR_ERR(sum_page);
1151
1152                         end_segno = segno - 1;
1153                         for (segno = start_segno; segno < end_segno; segno++) {
1154                                 sum_page = find_get_page(META_MAPPING(sbi),
1155                                                 GET_SUM_BLOCK(sbi, segno));
1156                                 f2fs_put_page(sum_page, 0);
1157                                 f2fs_put_page(sum_page, 0);
1158                         }
1159                         return err;
1160                 }
1161                 unlock_page(sum_page);
1162         }
1163
1164         blk_start_plug(&plug);
1165
1166         for (segno = start_segno; segno < end_segno; segno++) {
1167
1168                 /* find segment summary of victim */
1169                 sum_page = find_get_page(META_MAPPING(sbi),
1170                                         GET_SUM_BLOCK(sbi, segno));
1171                 f2fs_put_page(sum_page, 0);
1172
1173                 if (get_valid_blocks(sbi, segno, false) == 0)
1174                         goto freed;
1175                 if (__is_large_section(sbi) &&
1176                                 migrated >= sbi->migration_granularity)
1177                         goto skip;
1178                 if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1179                         goto skip;
1180
1181                 sum = page_address(sum_page);
1182                 if (type != GET_SUM_TYPE((&sum->footer))) {
1183                         f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1184                                  segno, type, GET_SUM_TYPE((&sum->footer)));
1185                         set_sbi_flag(sbi, SBI_NEED_FSCK);
1186                         f2fs_stop_checkpoint(sbi, false);
1187                         goto skip;
1188                 }
1189
1190                 /*
1191                  * this is to avoid deadlock:
1192                  * - lock_page(sum_page)         - f2fs_replace_block
1193                  *  - check_valid_map()            - down_write(sentry_lock)
1194                  *   - down_read(sentry_lock)     - change_curseg()
1195                  *                                  - lock_page(sum_page)
1196                  */
1197                 if (type == SUM_TYPE_NODE)
1198                         submitted += gc_node_segment(sbi, sum->entries, segno,
1199                                                                 gc_type);
1200                 else
1201                         submitted += gc_data_segment(sbi, sum->entries, gc_list,
1202                                                         segno, gc_type);
1203
1204                 stat_inc_seg_count(sbi, type, gc_type);
1205
1206 freed:
1207                 if (gc_type == FG_GC &&
1208                                 get_valid_blocks(sbi, segno, false) == 0)
1209                         seg_freed++;
1210                 migrated++;
1211
1212                 if (__is_large_section(sbi) && segno + 1 < end_segno)
1213                         sbi->next_victim_seg[gc_type] = segno + 1;
1214 skip:
1215                 f2fs_put_page(sum_page, 0);
1216         }
1217
1218         if (submitted)
1219                 f2fs_submit_merged_write(sbi,
1220                                 (type == SUM_TYPE_NODE) ? NODE : DATA);
1221
1222         blk_finish_plug(&plug);
1223
1224         stat_inc_call_count(sbi->stat_info);
1225
1226         return seg_freed;
1227 }
1228
1229 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1230                         bool background, unsigned int segno)
1231 {
1232         int gc_type = sync ? FG_GC : BG_GC;
1233         int sec_freed = 0, seg_freed = 0, total_freed = 0;
1234         int ret = 0;
1235         struct cp_control cpc;
1236         unsigned int init_segno = segno;
1237         struct gc_inode_list gc_list = {
1238                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
1239                 .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1240         };
1241         unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1242         unsigned long long first_skipped;
1243         unsigned int skipped_round = 0, round = 0;
1244
1245         trace_f2fs_gc_begin(sbi->sb, sync, background,
1246                                 get_pages(sbi, F2FS_DIRTY_NODES),
1247                                 get_pages(sbi, F2FS_DIRTY_DENTS),
1248                                 get_pages(sbi, F2FS_DIRTY_IMETA),
1249                                 free_sections(sbi),
1250                                 free_segments(sbi),
1251                                 reserved_segments(sbi),
1252                                 prefree_segments(sbi));
1253
1254         cpc.reason = __get_cp_reason(sbi);
1255         sbi->skipped_gc_rwsem = 0;
1256         first_skipped = last_skipped;
1257 gc_more:
1258         if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1259                 ret = -EINVAL;
1260                 goto stop;
1261         }
1262         if (unlikely(f2fs_cp_error(sbi))) {
1263                 ret = -EIO;
1264                 goto stop;
1265         }
1266
1267         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1268                 /*
1269                  * For example, if there are many prefree_segments below given
1270                  * threshold, we can make them free by checkpoint. Then, we
1271                  * secure free segments which doesn't need fggc any more.
1272                  */
1273                 if (prefree_segments(sbi) &&
1274                                 !is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1275                         ret = f2fs_write_checkpoint(sbi, &cpc);
1276                         if (ret)
1277                                 goto stop;
1278                 }
1279                 if (has_not_enough_free_secs(sbi, 0, 0))
1280                         gc_type = FG_GC;
1281         }
1282
1283         /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1284         if (gc_type == BG_GC && !background) {
1285                 ret = -EINVAL;
1286                 goto stop;
1287         }
1288         if (!__get_victim(sbi, &segno, gc_type)) {
1289                 ret = -ENODATA;
1290                 goto stop;
1291         }
1292
1293         seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
1294         if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
1295                 sec_freed++;
1296         total_freed += seg_freed;
1297
1298         if (gc_type == FG_GC) {
1299                 if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1300                                                 sbi->skipped_gc_rwsem)
1301                         skipped_round++;
1302                 last_skipped = sbi->skipped_atomic_files[FG_GC];
1303                 round++;
1304         }
1305
1306         if (gc_type == FG_GC)
1307                 sbi->cur_victim_sec = NULL_SEGNO;
1308
1309         if (sync)
1310                 goto stop;
1311
1312         if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1313                 if (skipped_round <= MAX_SKIP_GC_COUNT ||
1314                                         skipped_round * 2 < round) {
1315                         segno = NULL_SEGNO;
1316                         goto gc_more;
1317                 }
1318
1319                 if (first_skipped < last_skipped &&
1320                                 (last_skipped - first_skipped) >
1321                                                 sbi->skipped_gc_rwsem) {
1322                         f2fs_drop_inmem_pages_all(sbi, true);
1323                         segno = NULL_SEGNO;
1324                         goto gc_more;
1325                 }
1326                 if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1327                         ret = f2fs_write_checkpoint(sbi, &cpc);
1328         }
1329 stop:
1330         SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1331         SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1332
1333         trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1334                                 get_pages(sbi, F2FS_DIRTY_NODES),
1335                                 get_pages(sbi, F2FS_DIRTY_DENTS),
1336                                 get_pages(sbi, F2FS_DIRTY_IMETA),
1337                                 free_sections(sbi),
1338                                 free_segments(sbi),
1339                                 reserved_segments(sbi),
1340                                 prefree_segments(sbi));
1341
1342         mutex_unlock(&sbi->gc_mutex);
1343
1344         put_gc_inode(&gc_list);
1345
1346         if (sync && !ret)
1347                 ret = sec_freed ? 0 : -EAGAIN;
1348         return ret;
1349 }
1350
1351 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1352 {
1353         DIRTY_I(sbi)->v_ops = &default_v_ops;
1354
1355         sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1356
1357         /* give warm/cold data area from slower device */
1358         if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1359                 SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1360                                 GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1361 }
1362
1363 static int free_segment_range(struct f2fs_sb_info *sbi, unsigned int start,
1364                                                         unsigned int end)
1365 {
1366         int type;
1367         unsigned int segno, next_inuse;
1368         int err = 0;
1369
1370         /* Move out cursegs from the target range */
1371         for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++)
1372                 allocate_segment_for_resize(sbi, type, start, end);
1373
1374         /* do GC to move out valid blocks in the range */
1375         for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1376                 struct gc_inode_list gc_list = {
1377                         .ilist = LIST_HEAD_INIT(gc_list.ilist),
1378                         .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1379                 };
1380
1381                 mutex_lock(&sbi->gc_mutex);
1382                 do_garbage_collect(sbi, segno, &gc_list, FG_GC);
1383                 mutex_unlock(&sbi->gc_mutex);
1384                 put_gc_inode(&gc_list);
1385
1386                 if (get_valid_blocks(sbi, segno, true))
1387                         return -EAGAIN;
1388         }
1389
1390         err = f2fs_sync_fs(sbi->sb, 1);
1391         if (err)
1392                 return err;
1393
1394         next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1395         if (next_inuse <= end) {
1396                 f2fs_err(sbi, "segno %u should be free but still inuse!",
1397                          next_inuse);
1398                 f2fs_bug_on(sbi, 1);
1399         }
1400         return err;
1401 }
1402
1403 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1404 {
1405         struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1406         int section_count = le32_to_cpu(raw_sb->section_count);
1407         int segment_count = le32_to_cpu(raw_sb->segment_count);
1408         int segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1409         long long block_count = le64_to_cpu(raw_sb->block_count);
1410         int segs = secs * sbi->segs_per_sec;
1411
1412         raw_sb->section_count = cpu_to_le32(section_count + secs);
1413         raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1414         raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1415         raw_sb->block_count = cpu_to_le64(block_count +
1416                                         (long long)segs * sbi->blocks_per_seg);
1417 }
1418
1419 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1420 {
1421         int segs = secs * sbi->segs_per_sec;
1422         long long user_block_count =
1423                                 le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1424
1425         SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1426         MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1427         FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1428         FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1429         F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count +
1430                                         (long long)segs * sbi->blocks_per_seg);
1431 }
1432
1433 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1434 {
1435         __u64 old_block_count, shrunk_blocks;
1436         unsigned int secs;
1437         int gc_mode, gc_type;
1438         int err = 0;
1439         __u32 rem;
1440
1441         old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
1442         if (block_count > old_block_count)
1443                 return -EINVAL;
1444
1445         /* new fs size should align to section size */
1446         div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
1447         if (rem)
1448                 return -EINVAL;
1449
1450         if (block_count == old_block_count)
1451                 return 0;
1452
1453         if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
1454                 f2fs_err(sbi, "Should run fsck to repair first.");
1455                 return -EFSCORRUPTED;
1456         }
1457
1458         if (test_opt(sbi, DISABLE_CHECKPOINT)) {
1459                 f2fs_err(sbi, "Checkpoint should be enabled.");
1460                 return -EINVAL;
1461         }
1462
1463         freeze_bdev(sbi->sb->s_bdev);
1464
1465         shrunk_blocks = old_block_count - block_count;
1466         secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
1467         spin_lock(&sbi->stat_lock);
1468         if (shrunk_blocks + valid_user_blocks(sbi) +
1469                 sbi->current_reserved_blocks + sbi->unusable_block_count +
1470                 F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
1471                 err = -ENOSPC;
1472         else
1473                 sbi->user_block_count -= shrunk_blocks;
1474         spin_unlock(&sbi->stat_lock);
1475         if (err) {
1476                 thaw_bdev(sbi->sb->s_bdev, sbi->sb);
1477                 return err;
1478         }
1479
1480         mutex_lock(&sbi->resize_mutex);
1481         set_sbi_flag(sbi, SBI_IS_RESIZEFS);
1482
1483         mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1484
1485         MAIN_SECS(sbi) -= secs;
1486
1487         for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1488                 if (SIT_I(sbi)->last_victim[gc_mode] >=
1489                                         MAIN_SECS(sbi) * sbi->segs_per_sec)
1490                         SIT_I(sbi)->last_victim[gc_mode] = 0;
1491
1492         for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1493                 if (sbi->next_victim_seg[gc_type] >=
1494                                         MAIN_SECS(sbi) * sbi->segs_per_sec)
1495                         sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1496
1497         mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1498
1499         err = free_segment_range(sbi, MAIN_SECS(sbi) * sbi->segs_per_sec,
1500                         MAIN_SEGS(sbi) - 1);
1501         if (err)
1502                 goto out;
1503
1504         update_sb_metadata(sbi, -secs);
1505
1506         err = f2fs_commit_super(sbi, false);
1507         if (err) {
1508                 update_sb_metadata(sbi, secs);
1509                 goto out;
1510         }
1511
1512         update_fs_metadata(sbi, -secs);
1513         clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1514         err = f2fs_sync_fs(sbi->sb, 1);
1515         if (err) {
1516                 update_fs_metadata(sbi, secs);
1517                 update_sb_metadata(sbi, secs);
1518                 f2fs_commit_super(sbi, false);
1519         }
1520 out:
1521         if (err) {
1522                 set_sbi_flag(sbi, SBI_NEED_FSCK);
1523                 f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
1524
1525                 MAIN_SECS(sbi) += secs;
1526                 spin_lock(&sbi->stat_lock);
1527                 sbi->user_block_count += shrunk_blocks;
1528                 spin_unlock(&sbi->stat_lock);
1529         }
1530         clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1531         mutex_unlock(&sbi->resize_mutex);
1532         thaw_bdev(sbi->sb->s_bdev, sbi->sb);
1533         return err;
1534 }