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 #ifdef CONFIG_F2FS_CHECK_FS
 386                 /*
 387                  * skip selecting the invalid segno (that is failed due to block
 388                  * validity check failure during GC) to avoid endless GC loop in
 389                  * such cases.
 390                  */
 391                 if (test_bit(segno, sm->invalid_segmap))
 392                         goto next;
 393 #endif
 394
 395                 secno = GET_SEC_FROM_SEG(sbi, segno);
 396
 397                 if (sec_usage_check(sbi, secno))
 398                         goto next;
 399                 /* Don't touch checkpointed data */
 400                 if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
 401                                         get_ckpt_valid_blocks(sbi, segno) &&
 402                                         p.alloc_mode != SSR))
 403                         goto next;
 404                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 405                         goto next;
 406
 407                 cost = get_gc_cost(sbi, segno, &p);
 408
 409                 if (p.min_cost > cost) {
 410                         p.min_segno = segno;
 411                         p.min_cost = cost;
 412                 }
 413 next:
 414                 if (nsearched >= p.max_search) {
 415                         if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
 416                                 sm->last_victim[p.gc_mode] = last_victim + 1;
 417                         else
 418                                 sm->last_victim[p.gc_mode] = segno + 1;
 419                         sm->last_victim[p.gc_mode] %=
 420                                 (MAIN_SECS(sbi) * sbi->segs_per_sec);
 421                         break;
 422                 }
 423         }
 424         if (p.min_segno != NULL_SEGNO) {
 425 got_it:
 426                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 427 got_result:
 428                 if (p.alloc_mode == LFS) {
 429                         secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
 430                         if (gc_type == FG_GC)
 431                                 sbi->cur_victim_sec = secno;
 432                         else
 433                                 set_bit(secno, dirty_i->victim_secmap);
 434                 }
 435
 436         }
 437 out:
 438         if (p.min_segno != NULL_SEGNO)
 439                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 440                                 sbi->cur_victim_sec,
 441                                 prefree_segments(sbi), free_segments(sbi));
 442         mutex_unlock(&dirty_i->seglist_lock);
 443
 444         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 445 }
 446
 447 static const struct victim_selection default_v_ops = {
 448         .get_victim = get_victim_by_default,
 449 };
 450
 451 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 452 {
 453         struct inode_entry *ie;
 454
 455         ie = radix_tree_lookup(&gc_list->iroot, ino);
 456         if (ie)
 457                 return ie->inode;
 458         return NULL;
 459 }
 460
 461 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 462 {
 463         struct inode_entry *new_ie;
 464
 465         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
 466                 iput(inode);
 467                 return;
 468         }
 469         new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab, GFP_NOFS);
 470         new_ie->inode = inode;
 471
 472         f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
 473         list_add_tail(&new_ie->list, &gc_list->ilist);
 474 }
 475
 476 static void put_gc_inode(struct gc_inode_list *gc_list)
 477 {
 478         struct inode_entry *ie, *next_ie;
 479         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
 480                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
 481                 iput(ie->inode);
 482                 list_del(&ie->list);
 483                 kmem_cache_free(f2fs_inode_entry_slab, ie);
 484         }
 485 }
 486
 487 static int check_valid_map(struct f2fs_sb_info *sbi,
 488                                 unsigned int segno, int offset)
 489 {
 490         struct sit_info *sit_i = SIT_I(sbi);
 491         struct seg_entry *sentry;
 492         int ret;
 493
 494         down_read(&sit_i->sentry_lock);
 495         sentry = get_seg_entry(sbi, segno);
 496         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 497         up_read(&sit_i->sentry_lock);
 498         return ret;
 499 }
 500
 501 /*
 502  * This function compares node address got in summary with that in NAT.
 503  * On validity, copy that node with cold status, otherwise (invalid node)
 504  * ignore that.
 505  */
 506 static int gc_node_segment(struct f2fs_sb_info *sbi,
 507                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 508 {
 509         struct f2fs_summary *entry;
 510         block_t start_addr;
 511         int off;
 512         int phase = 0;
 513         bool fggc = (gc_type == FG_GC);
 514         int submitted = 0;
 515
 516         start_addr = START_BLOCK(sbi, segno);
 517
 518 next_step:
 519         entry = sum;
 520
 521         if (fggc && phase == 2)
 522                 atomic_inc(&sbi->wb_sync_req[NODE]);
 523
 524         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 525                 nid_t nid = le32_to_cpu(entry->nid);
 526                 struct page *node_page;
 527                 struct node_info ni;
 528                 int err;
 529
 530                 /* stop BG_GC if there is not enough free sections. */
 531                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 532                         return submitted;
 533
 534                 if (check_valid_map(sbi, segno, off) == 0)
 535                         continue;
 536
 537                 if (phase == 0) {
 538                         f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 539                                                         META_NAT, true);
 540                         continue;
 541                 }
 542
 543                 if (phase == 1) {
 544                         f2fs_ra_node_page(sbi, nid);
 545                         continue;
 546                 }
 547
 548                 /* phase == 2 */
 549                 node_page = f2fs_get_node_page(sbi, nid);
 550                 if (IS_ERR(node_page))
 551                         continue;
 552
 553                 /* block may become invalid during f2fs_get_node_page */
 554                 if (check_valid_map(sbi, segno, off) == 0) {
 555                         f2fs_put_page(node_page, 1);
 556                         continue;
 557                 }
 558
 559                 if (f2fs_get_node_info(sbi, nid, &ni)) {
 560                         f2fs_put_page(node_page, 1);
 561                         continue;
 562                 }
 563
 564                 if (ni.blk_addr != start_addr + off) {
 565                         f2fs_put_page(node_page, 1);
 566                         continue;
 567                 }
 568
 569                 err = f2fs_move_node_page(node_page, gc_type);
 570                 if (!err && gc_type == FG_GC)
 571                         submitted++;
 572                 stat_inc_node_blk_count(sbi, 1, gc_type);
 573         }
 574
 575         if (++phase < 3)
 576                 goto next_step;
 577
 578         if (fggc)
 579                 atomic_dec(&sbi->wb_sync_req[NODE]);
 580         return submitted;
 581 }
 582
 583 /*
 584  * Calculate start block index indicating the given node offset.
 585  * Be careful, caller should give this node offset only indicating direct node
 586  * blocks. If any node offsets, which point the other types of node blocks such
 587  * as indirect or double indirect node blocks, are given, it must be a caller's
 588  * bug.
 589  */
 590 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
 591 {
 592         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 593         unsigned int bidx;
 594
 595         if (node_ofs == 0)
 596                 return 0;
 597
 598         if (node_ofs <= 2) {
 599                 bidx = node_ofs - 1;
 600         } else if (node_ofs <= indirect_blks) {
 601                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 602                 bidx = node_ofs - 2 - dec;
 603         } else {
 604                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 605                 bidx = node_ofs - 5 - dec;
 606         }
 607         return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
 608 }
 609
 610 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 611                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 612 {
 613         struct page *node_page;
 614         nid_t nid;
 615         unsigned int ofs_in_node;
 616         block_t source_blkaddr;
 617
 618         nid = le32_to_cpu(sum->nid);
 619         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 620
 621         node_page = f2fs_get_node_page(sbi, nid);
 622         if (IS_ERR(node_page))
 623                 return false;
 624
 625         if (f2fs_get_node_info(sbi, nid, dni)) {
 626                 f2fs_put_page(node_page, 1);
 627                 return false;
 628         }
 629
 630         if (sum->version != dni->version) {
 631                 f2fs_warn(sbi, "%s: valid data with mismatched node version.",
 632                           __func__);
 633                 set_sbi_flag(sbi, SBI_NEED_FSCK);
 634         }
 635
 636         *nofs = ofs_of_node(node_page);
 637         source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
 638         f2fs_put_page(node_page, 1);
 639
 640         if (source_blkaddr != blkaddr) {
 641 #ifdef CONFIG_F2FS_CHECK_FS
 642                 unsigned int segno = GET_SEGNO(sbi, blkaddr);
 643                 unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
 644
 645                 if (unlikely(check_valid_map(sbi, segno, offset))) {
 646                         if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
 647                                 f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u\n",
 648                                                 blkaddr, source_blkaddr, segno);
 649                                 f2fs_bug_on(sbi, 1);
 650                         }
 651                 }
 652 #endif
 653                 return false;
 654         }
 655         return true;
 656 }
 657
 658 static int ra_data_block(struct inode *inode, pgoff_t index)
 659 {
 660         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 661         struct address_space *mapping = inode->i_mapping;
 662         struct dnode_of_data dn;
 663         struct page *page;
 664         struct extent_info ei = {0, 0, 0};
 665         struct f2fs_io_info fio = {
 666                 .sbi = sbi,
 667                 .ino = inode->i_ino,
 668                 .type = DATA,
 669                 .temp = COLD,
 670                 .op = REQ_OP_READ,
 671                 .op_flags = 0,
 672                 .encrypted_page = NULL,
 673                 .in_list = false,
 674                 .retry = false,
 675         };
 676         int err;
 677
 678         page = f2fs_grab_cache_page(mapping, index, true);
 679         if (!page)
 680                 return -ENOMEM;
 681
 682         if (f2fs_lookup_extent_cache(inode, index, &ei)) {
 683                 dn.data_blkaddr = ei.blk + index - ei.fofs;
 684                 if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
 685                                                 DATA_GENERIC_ENHANCE_READ))) {
 686                         err = -EFSCORRUPTED;
 687                         goto put_page;
 688                 }
 689                 goto got_it;
 690         }
 691
 692         set_new_dnode(&dn, inode, NULL, NULL, 0);
 693         err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
 694         if (err)
 695                 goto put_page;
 696         f2fs_put_dnode(&dn);
 697
 698         if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
 699                 err = -ENOENT;
 700                 goto put_page;
 701         }
 702         if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
 703                                                 DATA_GENERIC_ENHANCE))) {
 704                 err = -EFSCORRUPTED;
 705                 goto put_page;
 706         }
 707 got_it:
 708         /* read page */
 709         fio.page = page;
 710         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 711
 712         /*
 713          * don't cache encrypted data into meta inode until previous dirty
 714          * data were writebacked to avoid racing between GC and flush.
 715          */
 716         f2fs_wait_on_page_writeback(page, DATA, true, true);
 717
 718         f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
 719
 720         fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
 721                                         dn.data_blkaddr,
 722                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
 723         if (!fio.encrypted_page) {
 724                 err = -ENOMEM;
 725                 goto put_page;
 726         }
 727
 728         err = f2fs_submit_page_bio(&fio);
 729         if (err)
 730                 goto put_encrypted_page;
 731         f2fs_put_page(fio.encrypted_page, 0);
 732         f2fs_put_page(page, 1);
 733         return 0;
 734 put_encrypted_page:
 735         f2fs_put_page(fio.encrypted_page, 1);
 736 put_page:
 737         f2fs_put_page(page, 1);
 738         return err;
 739 }
 740
 741 /*
 742  * Move data block via META_MAPPING while keeping locked data page.
 743  * This can be used to move blocks, aka LBAs, directly on disk.
 744  */
 745 static int move_data_block(struct inode *inode, block_t bidx,
 746                                 int gc_type, unsigned int segno, int off)
 747 {
 748         struct f2fs_io_info fio = {
 749                 .sbi = F2FS_I_SB(inode),
 750                 .ino = inode->i_ino,
 751                 .type = DATA,
 752                 .temp = COLD,
 753                 .op = REQ_OP_READ,
 754                 .op_flags = 0,
 755                 .encrypted_page = NULL,
 756                 .in_list = false,
 757                 .retry = false,
 758         };
 759         struct dnode_of_data dn;
 760         struct f2fs_summary sum;
 761         struct node_info ni;
 762         struct page *page, *mpage;
 763         block_t newaddr;
 764         int err = 0;
 765         bool lfs_mode = test_opt(fio.sbi, LFS);
 766
 767         /* do not read out */
 768         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 769         if (!page)
 770                 return -ENOMEM;
 771
 772         if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
 773                 err = -ENOENT;
 774                 goto out;
 775         }
 776
 777         if (f2fs_is_atomic_file(inode)) {
 778                 F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
 779                 F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
 780                 err = -EAGAIN;
 781                 goto out;
 782         }
 783
 784         if (f2fs_is_pinned_file(inode)) {
 785                 f2fs_pin_file_control(inode, true);
 786                 err = -EAGAIN;
 787                 goto out;
 788         }
 789
 790         set_new_dnode(&dn, inode, NULL, NULL, 0);
 791         err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
 792         if (err)
 793                 goto out;
 794
 795         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 796                 ClearPageUptodate(page);
 797                 err = -ENOENT;
 798                 goto put_out;
 799         }
 800
 801         /*
 802          * don't cache encrypted data into meta inode until previous dirty
 803          * data were writebacked to avoid racing between GC and flush.
 804          */
 805         f2fs_wait_on_page_writeback(page, DATA, true, true);
 806
 807         f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
 808
 809         err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
 810         if (err)
 811                 goto put_out;
 812
 813         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
 814
 815         /* read page */
 816         fio.page = page;
 817         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 818
 819         if (lfs_mode)
 820                 down_write(&fio.sbi->io_order_lock);
 821
 822         mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
 823                                         fio.old_blkaddr, false);
 824         if (!mpage)
 825                 goto up_out;
 826
 827         fio.encrypted_page = mpage;
 828
 829         /* read source block in mpage */
 830         if (!PageUptodate(mpage)) {
 831                 err = f2fs_submit_page_bio(&fio);
 832                 if (err) {
 833                         f2fs_put_page(mpage, 1);
 834                         goto up_out;
 835                 }
 836                 lock_page(mpage);
 837                 if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
 838                                                 !PageUptodate(mpage))) {
 839                         err = -EIO;
 840                         f2fs_put_page(mpage, 1);
 841                         goto up_out;
 842                 }
 843         }
 844
 845         f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 846                                         &sum, CURSEG_COLD_DATA, NULL, false);
 847
 848         fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
 849                                 newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
 850         if (!fio.encrypted_page) {
 851                 err = -ENOMEM;
 852                 f2fs_put_page(mpage, 1);
 853                 goto recover_block;
 854         }
 855
 856         /* write target block */
 857         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
 858         memcpy(page_address(fio.encrypted_page),
 859                                 page_address(mpage), PAGE_SIZE);
 860         f2fs_put_page(mpage, 1);
 861         invalidate_mapping_pages(META_MAPPING(fio.sbi),
 862                                 fio.old_blkaddr, fio.old_blkaddr);
 863
 864         set_page_dirty(fio.encrypted_page);
 865         if (clear_page_dirty_for_io(fio.encrypted_page))
 866                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
 867
 868         set_page_writeback(fio.encrypted_page);
 869         ClearPageError(page);
 870
 871         /* allocate block address */
 872         f2fs_wait_on_page_writeback(dn.node_page, NODE, true, true);
 873
 874         fio.op = REQ_OP_WRITE;
 875         fio.op_flags = REQ_SYNC;
 876         fio.new_blkaddr = newaddr;
 877         f2fs_submit_page_write(&fio);
 878         if (fio.retry) {
 879                 err = -EAGAIN;
 880                 if (PageWriteback(fio.encrypted_page))
 881                         end_page_writeback(fio.encrypted_page);
 882                 goto put_page_out;
 883         }
 884
 885         f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
 886
 887         f2fs_update_data_blkaddr(&dn, newaddr);
 888         set_inode_flag(inode, FI_APPEND_WRITE);
 889         if (page->index == 0)
 890                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 891 put_page_out:
 892         f2fs_put_page(fio.encrypted_page, 1);
 893 recover_block:
 894         if (err)
 895                 f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
 896                                                                 true, true);
 897 up_out:
 898         if (lfs_mode)
 899                 up_write(&fio.sbi->io_order_lock);
 900 put_out:
 901         f2fs_put_dnode(&dn);
 902 out:
 903         f2fs_put_page(page, 1);
 904         return err;
 905 }
 906
 907 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
 908                                                         unsigned int segno, int off)
 909 {
 910         struct page *page;
 911         int err = 0;
 912
 913         page = f2fs_get_lock_data_page(inode, bidx, true);
 914         if (IS_ERR(page))
 915                 return PTR_ERR(page);
 916
 917         if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
 918                 err = -ENOENT;
 919                 goto out;
 920         }
 921
 922         if (f2fs_is_atomic_file(inode)) {
 923                 F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
 924                 F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
 925                 err = -EAGAIN;
 926                 goto out;
 927         }
 928         if (f2fs_is_pinned_file(inode)) {
 929                 if (gc_type == FG_GC)
 930                         f2fs_pin_file_control(inode, true);
 931                 err = -EAGAIN;
 932                 goto out;
 933         }
 934
 935         if (gc_type == BG_GC) {
 936                 if (PageWriteback(page)) {
 937                         err = -EAGAIN;
 938                         goto out;
 939                 }
 940                 set_page_dirty(page);
 941                 set_cold_data(page);
 942         } else {
 943                 struct f2fs_io_info fio = {
 944                         .sbi = F2FS_I_SB(inode),
 945                         .ino = inode->i_ino,
 946                         .type = DATA,
 947                         .temp = COLD,
 948                         .op = REQ_OP_WRITE,
 949                         .op_flags = REQ_SYNC,
 950                         .old_blkaddr = NULL_ADDR,
 951                         .page = page,
 952                         .encrypted_page = NULL,
 953                         .need_lock = LOCK_REQ,
 954                         .io_type = FS_GC_DATA_IO,
 955                 };
 956                 bool is_dirty = PageDirty(page);
 957
 958 retry:
 959                 f2fs_wait_on_page_writeback(page, DATA, true, true);
 960
 961                 set_page_dirty(page);
 962                 if (clear_page_dirty_for_io(page)) {
 963                         inode_dec_dirty_pages(inode);
 964                         f2fs_remove_dirty_inode(inode);
 965                 }
 966
 967                 set_cold_data(page);
 968
 969                 err = f2fs_do_write_data_page(&fio);
 970                 if (err) {
 971                         clear_cold_data(page);
 972                         if (err == -ENOMEM) {
 973                                 congestion_wait(BLK_RW_ASYNC, HZ/50);
 974                                 goto retry;
 975                         }
 976                         if (is_dirty)
 977                                 set_page_dirty(page);
 978                 }
 979         }
 980 out:
 981         f2fs_put_page(page, 1);
 982         return err;
 983 }
 984
 985 /*
 986  * This function tries to get parent node of victim data block, and identifies
 987  * data block validity. If the block is valid, copy that with cold status and
 988  * modify parent node.
 989  * If the parent node is not valid or the data block address is different,
 990  * the victim data block is ignored.
 991  */
 992 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 993                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 994 {
 995         struct super_block *sb = sbi->sb;
 996         struct f2fs_summary *entry;
 997         block_t start_addr;
 998         int off;
 999         int phase = 0;
1000         int submitted = 0;
1001
1002         start_addr = START_BLOCK(sbi, segno);
1003
1004 next_step:
1005         entry = sum;
1006
1007         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
1008                 struct page *data_page;
1009                 struct inode *inode;
1010                 struct node_info dni; /* dnode info for the data */
1011                 unsigned int ofs_in_node, nofs;
1012                 block_t start_bidx;
1013                 nid_t nid = le32_to_cpu(entry->nid);
1014
1015                 /* stop BG_GC if there is not enough free sections. */
1016                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
1017                         return submitted;
1018
1019                 if (check_valid_map(sbi, segno, off) == 0)
1020                         continue;
1021
1022                 if (phase == 0) {
1023                         f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1024                                                         META_NAT, true);
1025                         continue;
1026                 }
1027
1028                 if (phase == 1) {
1029                         f2fs_ra_node_page(sbi, nid);
1030                         continue;
1031                 }
1032
1033                 /* Get an inode by ino with checking validity */
1034                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1035                         continue;
1036
1037                 if (phase == 2) {
1038                         f2fs_ra_node_page(sbi, dni.ino);
1039                         continue;
1040                 }
1041
1042                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1043
1044                 if (phase == 3) {
1045                         inode = f2fs_iget(sb, dni.ino);
1046                         if (IS_ERR(inode) || is_bad_inode(inode))
1047                                 continue;
1048
1049                         if (!down_write_trylock(
1050                                 &F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1051                                 iput(inode);
1052                                 sbi->skipped_gc_rwsem++;
1053                                 continue;
1054                         }
1055
1056                         start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1057                                                                 ofs_in_node;
1058
1059                         if (f2fs_post_read_required(inode)) {
1060                                 int err = ra_data_block(inode, start_bidx);
1061
1062                                 up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1063                                 if (err) {
1064                                         iput(inode);
1065                                         continue;
1066                                 }
1067                                 add_gc_inode(gc_list, inode);
1068                                 continue;
1069                         }
1070
1071                         data_page = f2fs_get_read_data_page(inode,
1072                                                 start_bidx, REQ_RAHEAD, true);
1073                         up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1074                         if (IS_ERR(data_page)) {
1075                                 iput(inode);
1076                                 continue;
1077                         }
1078
1079                         f2fs_put_page(data_page, 0);
1080                         add_gc_inode(gc_list, inode);
1081                         continue;
1082                 }
1083
1084                 /* phase 4 */
1085                 inode = find_gc_inode(gc_list, dni.ino);
1086                 if (inode) {
1087                         struct f2fs_inode_info *fi = F2FS_I(inode);
1088                         bool locked = false;
1089                         int err;
1090
1091                         if (S_ISREG(inode->i_mode)) {
1092                                 if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
1093                                         continue;
1094                                 if (!down_write_trylock(
1095                                                 &fi->i_gc_rwsem[WRITE])) {
1096                                         sbi->skipped_gc_rwsem++;
1097                                         up_write(&fi->i_gc_rwsem[READ]);
1098                                         continue;
1099                                 }
1100                                 locked = true;
1101
1102                                 /* wait for all inflight aio data */
1103                                 inode_dio_wait(inode);
1104                         }
1105
1106                         start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1107                                                                 + ofs_in_node;
1108                         if (f2fs_post_read_required(inode))
1109                                 err = move_data_block(inode, start_bidx,
1110                                                         gc_type, segno, off);
1111                         else
1112                                 err = move_data_page(inode, start_bidx, gc_type,
1113                                                                 segno, off);
1114
1115                         if (!err && (gc_type == FG_GC ||
1116                                         f2fs_post_read_required(inode)))
1117                                 submitted++;
1118
1119                         if (locked) {
1120                                 up_write(&fi->i_gc_rwsem[WRITE]);
1121                                 up_write(&fi->i_gc_rwsem[READ]);
1122                         }
1123
1124                         stat_inc_data_blk_count(sbi, 1, gc_type);
1125                 }
1126         }
1127
1128         if (++phase < 5)
1129                 goto next_step;
1130
1131         return submitted;
1132 }
1133
1134 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1135                         int gc_type)
1136 {
1137         struct sit_info *sit_i = SIT_I(sbi);
1138         int ret;
1139
1140         down_write(&sit_i->sentry_lock);
1141         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1142                                               NO_CHECK_TYPE, LFS);
1143         up_write(&sit_i->sentry_lock);
1144         return ret;
1145 }
1146
1147 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1148                                 unsigned int start_segno,
1149                                 struct gc_inode_list *gc_list, int gc_type)
1150 {
1151         struct page *sum_page;
1152         struct f2fs_summary_block *sum;
1153         struct blk_plug plug;
1154         unsigned int segno = start_segno;
1155         unsigned int end_segno = start_segno + sbi->segs_per_sec;
1156         int seg_freed = 0, migrated = 0;
1157         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1158                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
1159         int submitted = 0;
1160
1161         if (__is_large_section(sbi))
1162                 end_segno = rounddown(end_segno, sbi->segs_per_sec);
1163
1164         /* readahead multi ssa blocks those have contiguous address */
1165         if (__is_large_section(sbi))
1166                 f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1167                                         end_segno - segno, META_SSA, true);
1168
1169         /* reference all summary page */
1170         while (segno < end_segno) {
1171                 sum_page = f2fs_get_sum_page(sbi, segno++);
1172                 if (IS_ERR(sum_page)) {
1173                         int err = PTR_ERR(sum_page);
1174
1175                         end_segno = segno - 1;
1176                         for (segno = start_segno; segno < end_segno; segno++) {
1177                                 sum_page = find_get_page(META_MAPPING(sbi),
1178                                                 GET_SUM_BLOCK(sbi, segno));
1179                                 f2fs_put_page(sum_page, 0);
1180                                 f2fs_put_page(sum_page, 0);
1181                         }
1182                         return err;
1183                 }
1184                 unlock_page(sum_page);
1185         }
1186
1187         blk_start_plug(&plug);
1188
1189         for (segno = start_segno; segno < end_segno; segno++) {
1190
1191                 /* find segment summary of victim */
1192                 sum_page = find_get_page(META_MAPPING(sbi),
1193                                         GET_SUM_BLOCK(sbi, segno));
1194                 f2fs_put_page(sum_page, 0);
1195
1196                 if (get_valid_blocks(sbi, segno, false) == 0)
1197                         goto freed;
1198                 if (__is_large_section(sbi) &&
1199                                 migrated >= sbi->migration_granularity)
1200                         goto skip;
1201                 if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1202                         goto skip;
1203
1204                 sum = page_address(sum_page);
1205                 if (type != GET_SUM_TYPE((&sum->footer))) {
1206                         f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1207                                  segno, type, GET_SUM_TYPE((&sum->footer)));
1208                         set_sbi_flag(sbi, SBI_NEED_FSCK);
1209                         f2fs_stop_checkpoint(sbi, false);
1210                         goto skip;
1211                 }
1212
1213                 /*
1214                  * this is to avoid deadlock:
1215                  * - lock_page(sum_page)         - f2fs_replace_block
1216                  *  - check_valid_map()            - down_write(sentry_lock)
1217                  *   - down_read(sentry_lock)     - change_curseg()
1218                  *                                  - lock_page(sum_page)
1219                  */
1220                 if (type == SUM_TYPE_NODE)
1221                         submitted += gc_node_segment(sbi, sum->entries, segno,
1222                                                                 gc_type);
1223                 else
1224                         submitted += gc_data_segment(sbi, sum->entries, gc_list,
1225                                                         segno, gc_type);
1226
1227                 stat_inc_seg_count(sbi, type, gc_type);
1228
1229 freed:
1230                 if (gc_type == FG_GC &&
1231                                 get_valid_blocks(sbi, segno, false) == 0)
1232                         seg_freed++;
1233                 migrated++;
1234
1235                 if (__is_large_section(sbi) && segno + 1 < end_segno)
1236                         sbi->next_victim_seg[gc_type] = segno + 1;
1237 skip:
1238                 f2fs_put_page(sum_page, 0);
1239         }
1240
1241         if (submitted)
1242                 f2fs_submit_merged_write(sbi,
1243                                 (type == SUM_TYPE_NODE) ? NODE : DATA);
1244
1245         blk_finish_plug(&plug);
1246
1247         stat_inc_call_count(sbi->stat_info);
1248
1249         return seg_freed;
1250 }
1251
1252 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1253                         bool background, unsigned int segno)
1254 {
1255         int gc_type = sync ? FG_GC : BG_GC;
1256         int sec_freed = 0, seg_freed = 0, total_freed = 0;
1257         int ret = 0;
1258         struct cp_control cpc;
1259         unsigned int init_segno = segno;
1260         struct gc_inode_list gc_list = {
1261                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
1262                 .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1263         };
1264         unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1265         unsigned long long first_skipped;
1266         unsigned int skipped_round = 0, round = 0;
1267
1268         trace_f2fs_gc_begin(sbi->sb, sync, background,
1269                                 get_pages(sbi, F2FS_DIRTY_NODES),
1270                                 get_pages(sbi, F2FS_DIRTY_DENTS),
1271                                 get_pages(sbi, F2FS_DIRTY_IMETA),
1272                                 free_sections(sbi),
1273                                 free_segments(sbi),
1274                                 reserved_segments(sbi),
1275                                 prefree_segments(sbi));
1276
1277         cpc.reason = __get_cp_reason(sbi);
1278         sbi->skipped_gc_rwsem = 0;
1279         first_skipped = last_skipped;
1280 gc_more:
1281         if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1282                 ret = -EINVAL;
1283                 goto stop;
1284         }
1285         if (unlikely(f2fs_cp_error(sbi))) {
1286                 ret = -EIO;
1287                 goto stop;
1288         }
1289
1290         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1291                 /*
1292                  * For example, if there are many prefree_segments below given
1293                  * threshold, we can make them free by checkpoint. Then, we
1294                  * secure free segments which doesn't need fggc any more.
1295                  */
1296                 if (prefree_segments(sbi) &&
1297                                 !is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1298                         ret = f2fs_write_checkpoint(sbi, &cpc);
1299                         if (ret)
1300                                 goto stop;
1301                 }
1302                 if (has_not_enough_free_secs(sbi, 0, 0))
1303                         gc_type = FG_GC;
1304         }
1305
1306         /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1307         if (gc_type == BG_GC && !background) {
1308                 ret = -EINVAL;
1309                 goto stop;
1310         }
1311         if (!__get_victim(sbi, &segno, gc_type)) {
1312                 ret = -ENODATA;
1313                 goto stop;
1314         }
1315
1316         seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
1317         if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
1318                 sec_freed++;
1319         total_freed += seg_freed;
1320
1321         if (gc_type == FG_GC) {
1322                 if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1323                                                 sbi->skipped_gc_rwsem)
1324                         skipped_round++;
1325                 last_skipped = sbi->skipped_atomic_files[FG_GC];
1326                 round++;
1327         }
1328
1329         if (gc_type == FG_GC && seg_freed)
1330                 sbi->cur_victim_sec = NULL_SEGNO;
1331
1332         if (sync)
1333                 goto stop;
1334
1335         if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1336                 if (skipped_round <= MAX_SKIP_GC_COUNT ||
1337                                         skipped_round * 2 < round) {
1338                         segno = NULL_SEGNO;
1339                         goto gc_more;
1340                 }
1341
1342                 if (first_skipped < last_skipped &&
1343                                 (last_skipped - first_skipped) >
1344                                                 sbi->skipped_gc_rwsem) {
1345                         f2fs_drop_inmem_pages_all(sbi, true);
1346                         segno = NULL_SEGNO;
1347                         goto gc_more;
1348                 }
1349                 if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1350                         ret = f2fs_write_checkpoint(sbi, &cpc);
1351         }
1352 stop:
1353         SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1354         SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1355
1356         trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1357                                 get_pages(sbi, F2FS_DIRTY_NODES),
1358                                 get_pages(sbi, F2FS_DIRTY_DENTS),
1359                                 get_pages(sbi, F2FS_DIRTY_IMETA),
1360                                 free_sections(sbi),
1361                                 free_segments(sbi),
1362                                 reserved_segments(sbi),
1363                                 prefree_segments(sbi));
1364
1365         mutex_unlock(&sbi->gc_mutex);
1366
1367         put_gc_inode(&gc_list);
1368
1369         if (sync && !ret)
1370                 ret = sec_freed ? 0 : -EAGAIN;
1371         return ret;
1372 }
1373
1374 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1375 {
1376         DIRTY_I(sbi)->v_ops = &default_v_ops;
1377
1378         sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1379
1380         /* give warm/cold data area from slower device */
1381         if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1382                 SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1383                                 GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1384 }
1385
1386 static int free_segment_range(struct f2fs_sb_info *sbi, unsigned int start,
1387                                                         unsigned int end)
1388 {
1389         int type;
1390         unsigned int segno, next_inuse;
1391         int err = 0;
1392
1393         /* Move out cursegs from the target range */
1394         for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++)
1395                 allocate_segment_for_resize(sbi, type, start, end);
1396
1397         /* do GC to move out valid blocks in the range */
1398         for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1399                 struct gc_inode_list gc_list = {
1400                         .ilist = LIST_HEAD_INIT(gc_list.ilist),
1401                         .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1402                 };
1403
1404                 mutex_lock(&sbi->gc_mutex);
1405                 do_garbage_collect(sbi, segno, &gc_list, FG_GC);
1406                 mutex_unlock(&sbi->gc_mutex);
1407                 put_gc_inode(&gc_list);
1408
1409                 if (get_valid_blocks(sbi, segno, true))
1410                         return -EAGAIN;
1411         }
1412
1413         err = f2fs_sync_fs(sbi->sb, 1);
1414         if (err)
1415                 return err;
1416
1417         next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1418         if (next_inuse <= end) {
1419                 f2fs_err(sbi, "segno %u should be free but still inuse!",
1420                          next_inuse);
1421                 f2fs_bug_on(sbi, 1);
1422         }
1423         return err;
1424 }
1425
1426 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1427 {
1428         struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1429         int section_count = le32_to_cpu(raw_sb->section_count);
1430         int segment_count = le32_to_cpu(raw_sb->segment_count);
1431         int segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1432         long long block_count = le64_to_cpu(raw_sb->block_count);
1433         int segs = secs * sbi->segs_per_sec;
1434
1435         raw_sb->section_count = cpu_to_le32(section_count + secs);
1436         raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1437         raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1438         raw_sb->block_count = cpu_to_le64(block_count +
1439                                         (long long)segs * sbi->blocks_per_seg);
1440 }
1441
1442 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1443 {
1444         int segs = secs * sbi->segs_per_sec;
1445         long long user_block_count =
1446                                 le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1447
1448         SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1449         MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1450         FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1451         FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1452         F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count +
1453                                         (long long)segs * sbi->blocks_per_seg);
1454 }
1455
1456 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1457 {
1458         __u64 old_block_count, shrunk_blocks;
1459         unsigned int secs;
1460         int gc_mode, gc_type;
1461         int err = 0;
1462         __u32 rem;
1463
1464         old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
1465         if (block_count > old_block_count)
1466                 return -EINVAL;
1467
1468         /* new fs size should align to section size */
1469         div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
1470         if (rem)
1471                 return -EINVAL;
1472
1473         if (block_count == old_block_count)
1474                 return 0;
1475
1476         if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
1477                 f2fs_err(sbi, "Should run fsck to repair first.");
1478                 return -EFSCORRUPTED;
1479         }
1480
1481         if (test_opt(sbi, DISABLE_CHECKPOINT)) {
1482                 f2fs_err(sbi, "Checkpoint should be enabled.");
1483                 return -EINVAL;
1484         }
1485
1486         freeze_bdev(sbi->sb->s_bdev);
1487
1488         shrunk_blocks = old_block_count - block_count;
1489         secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
1490         spin_lock(&sbi->stat_lock);
1491         if (shrunk_blocks + valid_user_blocks(sbi) +
1492                 sbi->current_reserved_blocks + sbi->unusable_block_count +
1493                 F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
1494                 err = -ENOSPC;
1495         else
1496                 sbi->user_block_count -= shrunk_blocks;
1497         spin_unlock(&sbi->stat_lock);
1498         if (err) {
1499                 thaw_bdev(sbi->sb->s_bdev, sbi->sb);
1500                 return err;
1501         }
1502
1503         mutex_lock(&sbi->resize_mutex);
1504         set_sbi_flag(sbi, SBI_IS_RESIZEFS);
1505
1506         mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1507
1508         MAIN_SECS(sbi) -= secs;
1509
1510         for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1511                 if (SIT_I(sbi)->last_victim[gc_mode] >=
1512                                         MAIN_SECS(sbi) * sbi->segs_per_sec)
1513                         SIT_I(sbi)->last_victim[gc_mode] = 0;
1514
1515         for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1516                 if (sbi->next_victim_seg[gc_type] >=
1517                                         MAIN_SECS(sbi) * sbi->segs_per_sec)
1518                         sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1519
1520         mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1521
1522         err = free_segment_range(sbi, MAIN_SECS(sbi) * sbi->segs_per_sec,
1523                         MAIN_SEGS(sbi) - 1);
1524         if (err)
1525                 goto out;
1526
1527         update_sb_metadata(sbi, -secs);
1528
1529         err = f2fs_commit_super(sbi, false);
1530         if (err) {
1531                 update_sb_metadata(sbi, secs);
1532                 goto out;
1533         }
1534
1535         update_fs_metadata(sbi, -secs);
1536         clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1537         err = f2fs_sync_fs(sbi->sb, 1);
1538         if (err) {
1539                 update_fs_metadata(sbi, secs);
1540                 update_sb_metadata(sbi, secs);
1541                 f2fs_commit_super(sbi, false);
1542         }
1543 out:
1544         if (err) {
1545                 set_sbi_flag(sbi, SBI_NEED_FSCK);
1546                 f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
1547
1548                 MAIN_SECS(sbi) += secs;
1549                 spin_lock(&sbi->stat_lock);
1550                 sbi->user_block_count += shrunk_blocks;
1551                 spin_unlock(&sbi->stat_lock);
1552         }
1553         clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1554         mutex_unlock(&sbi->resize_mutex);
1555         thaw_bdev(sbi->sb->s_bdev, sbi->sb);
1556         return err;
1557 }