fs/f2fs/gc.c

   1 /*
   2  * fs/f2fs/gc.c
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *             http://www.samsung.com/
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/module.h>
  13 #include <linux/backing-dev.h>
  14 #include <linux/init.h>
  15 #include <linux/f2fs_fs.h>
  16 #include <linux/kthread.h>
  17 #include <linux/delay.h>
  18 #include <linux/freezer.h>
  19
  20 #include "f2fs.h"
  21 #include "node.h"
  22 #include "segment.h"
  23 #include "gc.h"
  24 #include <trace/events/f2fs.h>
  25
  26 static int gc_thread_func(void *data)
  27 {
  28         struct f2fs_sb_info *sbi = data;
  29         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
  30         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
  31         unsigned int wait_ms;
  32
  33         wait_ms = gc_th->min_sleep_time;
  34
  35         set_freezable();
  36         do {
  37                 wait_event_interruptible_timeout(*wq,
  38                                 kthread_should_stop() || freezing(current) ||
  39                                 gc_th->gc_wake,
  40                                 msecs_to_jiffies(wait_ms));
  41
  42                 /* give it a try one time */
  43                 if (gc_th->gc_wake)
  44                         gc_th->gc_wake = 0;
  45
  46                 if (try_to_freeze())
  47                         continue;
  48                 if (kthread_should_stop())
  49                         break;
  50
  51                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
  52                         increase_sleep_time(gc_th, &wait_ms);
  53                         continue;
  54                 }
  55
  56 #ifdef CONFIG_F2FS_FAULT_INJECTION
  57                 if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
  58                         f2fs_show_injection_info(FAULT_CHECKPOINT);
  59                         f2fs_stop_checkpoint(sbi, false);
  60                 }
  61 #endif
  62
  63                 if (!sb_start_write_trylock(sbi->sb))
  64                         continue;
  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 (!mutex_trylock(&sbi->gc_mutex))
  80                         goto next;
  81
  82                 if (gc_th->gc_urgent) {
  83                         wait_ms = gc_th->urgent_sleep_time;
  84                         goto do_gc;
  85                 }
  86
  87                 if (!is_idle(sbi)) {
  88                         increase_sleep_time(gc_th, &wait_ms);
  89                         mutex_unlock(&sbi->gc_mutex);
  90                         goto next;
  91                 }
  92
  93                 if (has_enough_invalid_blocks(sbi))
  94                         decrease_sleep_time(gc_th, &wait_ms);
  95                 else
  96                         increase_sleep_time(gc_th, &wait_ms);
  97 do_gc:
  98                 stat_inc_bggc_count(sbi);
  99
 100                 /* if return value is not zero, no victim was selected */
 101                 if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC), true, NULL_SEGNO))
 102                         wait_ms = gc_th->no_gc_sleep_time;
 103
 104                 trace_f2fs_background_gc(sbi->sb, wait_ms,
 105                                 prefree_segments(sbi), free_segments(sbi));
 106
 107                 /* balancing f2fs's metadata periodically */
 108                 f2fs_balance_fs_bg(sbi);
 109 next:
 110                 sb_end_write(sbi->sb);
 111
 112         } while (!kthread_should_stop());
 113         return 0;
 114 }
 115
 116 int start_gc_thread(struct f2fs_sb_info *sbi)
 117 {
 118         struct f2fs_gc_kthread *gc_th;
 119         dev_t dev = sbi->sb->s_bdev->bd_dev;
 120         int err = 0;
 121
 122         gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
 123         if (!gc_th) {
 124                 err = -ENOMEM;
 125                 goto out;
 126         }
 127
 128         gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
 129         gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
 130         gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
 131         gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
 132
 133         gc_th->gc_idle = 0;
 134         gc_th->gc_urgent = 0;
 135         gc_th->gc_wake= 0;
 136
 137         sbi->gc_thread = gc_th;
 138         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 139         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 140                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 141         if (IS_ERR(gc_th->f2fs_gc_task)) {
 142                 err = PTR_ERR(gc_th->f2fs_gc_task);
 143                 kfree(gc_th);
 144                 sbi->gc_thread = NULL;
 145         }
 146 out:
 147         return err;
 148 }
 149
 150 void stop_gc_thread(struct f2fs_sb_info *sbi)
 151 {
 152         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 153         if (!gc_th)
 154                 return;
 155         kthread_stop(gc_th->f2fs_gc_task);
 156         kfree(gc_th);
 157         sbi->gc_thread = NULL;
 158 }
 159
 160 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
 161 {
 162         int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 163
 164         if (gc_th && gc_th->gc_idle) {
 165                 if (gc_th->gc_idle == 1)
 166                         gc_mode = GC_CB;
 167                 else if (gc_th->gc_idle == 2)
 168                         gc_mode = GC_GREEDY;
 169         }
 170         return gc_mode;
 171 }
 172
 173 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 174                         int type, struct victim_sel_policy *p)
 175 {
 176         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 177
 178         if (p->alloc_mode == SSR) {
 179                 p->gc_mode = GC_GREEDY;
 180                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 181                 p->max_search = dirty_i->nr_dirty[type];
 182                 p->ofs_unit = 1;
 183         } else {
 184                 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
 185                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 186                 p->max_search = dirty_i->nr_dirty[DIRTY];
 187                 p->ofs_unit = sbi->segs_per_sec;
 188         }
 189
 190         /* we need to check every dirty segments in the FG_GC case */
 191         if (gc_type != FG_GC && p->max_search > sbi->max_victim_search)
 192                 p->max_search = sbi->max_victim_search;
 193
 194         /* let's select beginning hot/small space first */
 195         if (type == CURSEG_HOT_DATA || IS_NODESEG(type))
 196                 p->offset = 0;
 197         else
 198                 p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
 199 }
 200
 201 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 202                                 struct victim_sel_policy *p)
 203 {
 204         /* SSR allocates in a segment unit */
 205         if (p->alloc_mode == SSR)
 206                 return sbi->blocks_per_seg;
 207         if (p->gc_mode == GC_GREEDY)
 208                 return 2 * sbi->blocks_per_seg * p->ofs_unit;
 209         else if (p->gc_mode == GC_CB)
 210                 return UINT_MAX;
 211         else /* No other gc_mode */
 212                 return 0;
 213 }
 214
 215 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 216 {
 217         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 218         unsigned int secno;
 219
 220         /*
 221          * If the gc_type is FG_GC, we can select victim segments
 222          * selected by background GC before.
 223          * Those segments guarantee they have small valid blocks.
 224          */
 225         for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
 226                 if (sec_usage_check(sbi, secno))
 227                         continue;
 228
 229                 if (no_fggc_candidate(sbi, secno))
 230                         continue;
 231
 232                 clear_bit(secno, dirty_i->victim_secmap);
 233                 return GET_SEG_FROM_SEC(sbi, secno);
 234         }
 235         return NULL_SEGNO;
 236 }
 237
 238 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 239 {
 240         struct sit_info *sit_i = SIT_I(sbi);
 241         unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
 242         unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
 243         unsigned long long mtime = 0;
 244         unsigned int vblocks;
 245         unsigned char age = 0;
 246         unsigned char u;
 247         unsigned int i;
 248
 249         for (i = 0; i < sbi->segs_per_sec; i++)
 250                 mtime += get_seg_entry(sbi, start + i)->mtime;
 251         vblocks = get_valid_blocks(sbi, segno, true);
 252
 253         mtime = div_u64(mtime, sbi->segs_per_sec);
 254         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 255
 256         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 257
 258         /* Handle if the system time has changed by the user */
 259         if (mtime < sit_i->min_mtime)
 260                 sit_i->min_mtime = mtime;
 261         if (mtime > sit_i->max_mtime)
 262                 sit_i->max_mtime = mtime;
 263         if (sit_i->max_mtime != sit_i->min_mtime)
 264                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 265                                 sit_i->max_mtime - sit_i->min_mtime);
 266
 267         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 268 }
 269
 270 static unsigned int get_greedy_cost(struct f2fs_sb_info *sbi,
 271                                                 unsigned int segno)
 272 {
 273         unsigned int valid_blocks =
 274                         get_valid_blocks(sbi, segno, true);
 275
 276         return IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 277                                 valid_blocks * 2 : valid_blocks;
 278 }
 279
 280 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 281                         unsigned int segno, struct victim_sel_policy *p)
 282 {
 283         if (p->alloc_mode == SSR)
 284                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 285
 286         /* alloc_mode == LFS */
 287         if (p->gc_mode == GC_GREEDY)
 288                 return get_greedy_cost(sbi, segno);
 289         else
 290                 return get_cb_cost(sbi, segno);
 291 }
 292
 293 static unsigned int count_bits(const unsigned long *addr,
 294                                 unsigned int offset, unsigned int len)
 295 {
 296         unsigned int end = offset + len, sum = 0;
 297
 298         while (offset < end) {
 299                 if (test_bit(offset++, addr))
 300                         ++sum;
 301         }
 302         return sum;
 303 }
 304
 305 /*
 306  * This function is called from two paths.
 307  * One is garbage collection and the other is SSR segment selection.
 308  * When it is called during GC, it just gets a victim segment
 309  * and it does not remove it from dirty seglist.
 310  * When it is called from SSR segment selection, it finds a segment
 311  * which has minimum valid blocks and removes it from dirty seglist.
 312  */
 313 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 314                 unsigned int *result, int gc_type, int type, char alloc_mode)
 315 {
 316         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 317         struct sit_info *sm = SIT_I(sbi);
 318         struct victim_sel_policy p;
 319         unsigned int secno, last_victim;
 320         unsigned int last_segment = MAIN_SEGS(sbi);
 321         unsigned int nsearched = 0;
 322
 323         mutex_lock(&dirty_i->seglist_lock);
 324
 325         p.alloc_mode = alloc_mode;
 326         select_policy(sbi, gc_type, type, &p);
 327
 328         p.min_segno = NULL_SEGNO;
 329         p.min_cost = get_max_cost(sbi, &p);
 330
 331         if (*result != NULL_SEGNO) {
 332                 if (IS_DATASEG(get_seg_entry(sbi, *result)->type) &&
 333                         get_valid_blocks(sbi, *result, false) &&
 334                         !sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
 335                         p.min_segno = *result;
 336                 goto out;
 337         }
 338
 339         if (p.max_search == 0)
 340                 goto out;
 341
 342         last_victim = sm->last_victim[p.gc_mode];
 343         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 344                 p.min_segno = check_bg_victims(sbi);
 345                 if (p.min_segno != NULL_SEGNO)
 346                         goto got_it;
 347         }
 348
 349         while (1) {
 350                 unsigned long cost;
 351                 unsigned int segno;
 352
 353                 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
 354                 if (segno >= last_segment) {
 355                         if (sm->last_victim[p.gc_mode]) {
 356                                 last_segment =
 357                                         sm->last_victim[p.gc_mode];
 358                                 sm->last_victim[p.gc_mode] = 0;
 359                                 p.offset = 0;
 360                                 continue;
 361                         }
 362                         break;
 363                 }
 364
 365                 p.offset = segno + p.ofs_unit;
 366                 if (p.ofs_unit > 1) {
 367                         p.offset -= segno % p.ofs_unit;
 368                         nsearched += count_bits(p.dirty_segmap,
 369                                                 p.offset - p.ofs_unit,
 370                                                 p.ofs_unit);
 371                 } else {
 372                         nsearched++;
 373                 }
 374
 375                 secno = GET_SEC_FROM_SEG(sbi, segno);
 376
 377                 if (sec_usage_check(sbi, secno))
 378                         goto next;
 379                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 380                         goto next;
 381                 if (gc_type == FG_GC && p.alloc_mode == LFS &&
 382                                         no_fggc_candidate(sbi, secno))
 383                         goto next;
 384
 385                 cost = get_gc_cost(sbi, segno, &p);
 386
 387                 if (p.min_cost > cost) {
 388                         p.min_segno = segno;
 389                         p.min_cost = cost;
 390                 }
 391 next:
 392                 if (nsearched >= p.max_search) {
 393                         if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
 394                                 sm->last_victim[p.gc_mode] = last_victim + 1;
 395                         else
 396                                 sm->last_victim[p.gc_mode] = segno + 1;
 397                         sm->last_victim[p.gc_mode] %= MAIN_SEGS(sbi);
 398                         break;
 399                 }
 400         }
 401         if (p.min_segno != NULL_SEGNO) {
 402 got_it:
 403                 if (p.alloc_mode == LFS) {
 404                         secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
 405                         if (gc_type == FG_GC)
 406                                 sbi->cur_victim_sec = secno;
 407                         else
 408                                 set_bit(secno, dirty_i->victim_secmap);
 409                 }
 410                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 411
 412                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 413                                 sbi->cur_victim_sec,
 414                                 prefree_segments(sbi), free_segments(sbi));
 415         }
 416 out:
 417         mutex_unlock(&dirty_i->seglist_lock);
 418
 419         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 420 }
 421
 422 static const struct victim_selection default_v_ops = {
 423         .get_victim = get_victim_by_default,
 424 };
 425
 426 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 427 {
 428         struct inode_entry *ie;
 429
 430         ie = radix_tree_lookup(&gc_list->iroot, ino);
 431         if (ie)
 432                 return ie->inode;
 433         return NULL;
 434 }
 435
 436 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 437 {
 438         struct inode_entry *new_ie;
 439
 440         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
 441                 iput(inode);
 442                 return;
 443         }
 444         new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
 445         new_ie->inode = inode;
 446
 447         f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
 448         list_add_tail(&new_ie->list, &gc_list->ilist);
 449 }
 450
 451 static void put_gc_inode(struct gc_inode_list *gc_list)
 452 {
 453         struct inode_entry *ie, *next_ie;
 454         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
 455                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
 456                 iput(ie->inode);
 457                 list_del(&ie->list);
 458                 kmem_cache_free(inode_entry_slab, ie);
 459         }
 460 }
 461
 462 static int check_valid_map(struct f2fs_sb_info *sbi,
 463                                 unsigned int segno, int offset)
 464 {
 465         struct sit_info *sit_i = SIT_I(sbi);
 466         struct seg_entry *sentry;
 467         int ret;
 468
 469         mutex_lock(&sit_i->sentry_lock);
 470         sentry = get_seg_entry(sbi, segno);
 471         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 472         mutex_unlock(&sit_i->sentry_lock);
 473         return ret;
 474 }
 475
 476 /*
 477  * This function compares node address got in summary with that in NAT.
 478  * On validity, copy that node with cold status, otherwise (invalid node)
 479  * ignore that.
 480  */
 481 static void gc_node_segment(struct f2fs_sb_info *sbi,
 482                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 483 {
 484         struct f2fs_summary *entry;
 485         block_t start_addr;
 486         int off;
 487         int phase = 0;
 488
 489         start_addr = START_BLOCK(sbi, segno);
 490
 491 next_step:
 492         entry = sum;
 493
 494         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 495                 nid_t nid = le32_to_cpu(entry->nid);
 496                 struct page *node_page;
 497                 struct node_info ni;
 498
 499                 /* stop BG_GC if there is not enough free sections. */
 500                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 501                         return;
 502
 503                 if (check_valid_map(sbi, segno, off) == 0)
 504                         continue;
 505
 506                 if (phase == 0) {
 507                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 508                                                         META_NAT, true);
 509                         continue;
 510                 }
 511
 512                 if (phase == 1) {
 513                         ra_node_page(sbi, nid);
 514                         continue;
 515                 }
 516
 517                 /* phase == 2 */
 518                 node_page = get_node_page(sbi, nid);
 519                 if (IS_ERR(node_page))
 520                         continue;
 521
 522                 /* block may become invalid during get_node_page */
 523                 if (check_valid_map(sbi, segno, off) == 0) {
 524                         f2fs_put_page(node_page, 1);
 525                         continue;
 526                 }
 527
 528                 get_node_info(sbi, nid, &ni);
 529                 if (ni.blk_addr != start_addr + off) {
 530                         f2fs_put_page(node_page, 1);
 531                         continue;
 532                 }
 533
 534                 move_node_page(node_page, gc_type);
 535                 stat_inc_node_blk_count(sbi, 1, gc_type);
 536         }
 537
 538         if (++phase < 3)
 539                 goto next_step;
 540 }
 541
 542 /*
 543  * Calculate start block index indicating the given node offset.
 544  * Be careful, caller should give this node offset only indicating direct node
 545  * blocks. If any node offsets, which point the other types of node blocks such
 546  * as indirect or double indirect node blocks, are given, it must be a caller's
 547  * bug.
 548  */
 549 block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
 550 {
 551         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 552         unsigned int bidx;
 553
 554         if (node_ofs == 0)
 555                 return 0;
 556
 557         if (node_ofs <= 2) {
 558                 bidx = node_ofs - 1;
 559         } else if (node_ofs <= indirect_blks) {
 560                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 561                 bidx = node_ofs - 2 - dec;
 562         } else {
 563                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 564                 bidx = node_ofs - 5 - dec;
 565         }
 566         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
 567 }
 568
 569 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 570                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 571 {
 572         struct page *node_page;
 573         nid_t nid;
 574         unsigned int ofs_in_node;
 575         block_t source_blkaddr;
 576
 577         nid = le32_to_cpu(sum->nid);
 578         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 579
 580         node_page = get_node_page(sbi, nid);
 581         if (IS_ERR(node_page))
 582                 return false;
 583
 584         get_node_info(sbi, nid, dni);
 585
 586         if (sum->version != dni->version) {
 587                 f2fs_msg(sbi->sb, KERN_WARNING,
 588                                 "%s: valid data with mismatched node version.",
 589                                 __func__);
 590                 set_sbi_flag(sbi, SBI_NEED_FSCK);
 591         }
 592
 593         *nofs = ofs_of_node(node_page);
 594         source_blkaddr = datablock_addr(NULL, node_page, ofs_in_node);
 595         f2fs_put_page(node_page, 1);
 596
 597         if (source_blkaddr != blkaddr)
 598                 return false;
 599         return true;
 600 }
 601
 602 /*
 603  * Move data block via META_MAPPING while keeping locked data page.
 604  * This can be used to move blocks, aka LBAs, directly on disk.
 605  */
 606 static void move_data_block(struct inode *inode, block_t bidx,
 607                                         unsigned int segno, int off)
 608 {
 609         struct f2fs_io_info fio = {
 610                 .sbi = F2FS_I_SB(inode),
 611                 .type = DATA,
 612                 .temp = COLD,
 613                 .op = REQ_OP_READ,
 614                 .op_flags = 0,
 615                 .encrypted_page = NULL,
 616                 .in_list = false,
 617         };
 618         struct dnode_of_data dn;
 619         struct f2fs_summary sum;
 620         struct node_info ni;
 621         struct page *page;
 622         block_t newaddr;
 623         int err;
 624
 625         /* do not read out */
 626         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 627         if (!page)
 628                 return;
 629
 630         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 631                 goto out;
 632
 633         if (f2fs_is_atomic_file(inode))
 634                 goto out;
 635
 636         set_new_dnode(&dn, inode, NULL, NULL, 0);
 637         err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
 638         if (err)
 639                 goto out;
 640
 641         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 642                 ClearPageUptodate(page);
 643                 goto put_out;
 644         }
 645
 646         /*
 647          * don't cache encrypted data into meta inode until previous dirty
 648          * data were writebacked to avoid racing between GC and flush.
 649          */
 650         f2fs_wait_on_page_writeback(page, DATA, true);
 651
 652         get_node_info(fio.sbi, dn.nid, &ni);
 653         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
 654
 655         /* read page */
 656         fio.page = page;
 657         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 658
 659         allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 660                                         &sum, CURSEG_COLD_DATA, NULL, false);
 661
 662         fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
 663                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
 664         if (!fio.encrypted_page) {
 665                 err = -ENOMEM;
 666                 goto recover_block;
 667         }
 668
 669         err = f2fs_submit_page_bio(&fio);
 670         if (err)
 671                 goto put_page_out;
 672
 673         /* write page */
 674         lock_page(fio.encrypted_page);
 675
 676         if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
 677                 err = -EIO;
 678                 goto put_page_out;
 679         }
 680         if (unlikely(!PageUptodate(fio.encrypted_page))) {
 681                 err = -EIO;
 682                 goto put_page_out;
 683         }
 684
 685         set_page_dirty(fio.encrypted_page);
 686         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
 687         if (clear_page_dirty_for_io(fio.encrypted_page))
 688                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
 689
 690         set_page_writeback(fio.encrypted_page);
 691
 692         /* allocate block address */
 693         f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
 694
 695         fio.op = REQ_OP_WRITE;
 696         fio.op_flags = REQ_SYNC;
 697         fio.new_blkaddr = newaddr;
 698         f2fs_submit_page_write(&fio);
 699
 700         f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
 701
 702         f2fs_update_data_blkaddr(&dn, newaddr);
 703         set_inode_flag(inode, FI_APPEND_WRITE);
 704         if (page->index == 0)
 705                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 706 put_page_out:
 707         f2fs_put_page(fio.encrypted_page, 1);
 708 recover_block:
 709         if (err)
 710                 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
 711                                                                 true, true);
 712 put_out:
 713         f2fs_put_dnode(&dn);
 714 out:
 715         f2fs_put_page(page, 1);
 716 }
 717
 718 static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
 719                                                         unsigned int segno, int off)
 720 {
 721         struct page *page;
 722
 723         page = get_lock_data_page(inode, bidx, true);
 724         if (IS_ERR(page))
 725                 return;
 726
 727         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 728                 goto out;
 729
 730         if (f2fs_is_atomic_file(inode))
 731                 goto out;
 732
 733         if (gc_type == BG_GC) {
 734                 if (PageWriteback(page))
 735                         goto out;
 736                 set_page_dirty(page);
 737                 set_cold_data(page);
 738         } else {
 739                 struct f2fs_io_info fio = {
 740                         .sbi = F2FS_I_SB(inode),
 741                         .type = DATA,
 742                         .temp = COLD,
 743                         .op = REQ_OP_WRITE,
 744                         .op_flags = REQ_SYNC,
 745                         .old_blkaddr = NULL_ADDR,
 746                         .page = page,
 747                         .encrypted_page = NULL,
 748                         .need_lock = LOCK_REQ,
 749                         .io_type = FS_GC_DATA_IO,
 750                 };
 751                 bool is_dirty = PageDirty(page);
 752                 int err;
 753
 754 retry:
 755                 set_page_dirty(page);
 756                 f2fs_wait_on_page_writeback(page, DATA, true);
 757                 if (clear_page_dirty_for_io(page)) {
 758                         inode_dec_dirty_pages(inode);
 759                         remove_dirty_inode(inode);
 760                 }
 761
 762                 set_cold_data(page);
 763
 764                 err = do_write_data_page(&fio);
 765                 if (err == -ENOMEM && is_dirty) {
 766                         congestion_wait(BLK_RW_ASYNC, HZ/50);
 767                         goto retry;
 768                 }
 769         }
 770 out:
 771         f2fs_put_page(page, 1);
 772 }
 773
 774 /*
 775  * This function tries to get parent node of victim data block, and identifies
 776  * data block validity. If the block is valid, copy that with cold status and
 777  * modify parent node.
 778  * If the parent node is not valid or the data block address is different,
 779  * the victim data block is ignored.
 780  */
 781 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 782                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 783 {
 784         struct super_block *sb = sbi->sb;
 785         struct f2fs_summary *entry;
 786         block_t start_addr;
 787         int off;
 788         int phase = 0;
 789
 790         start_addr = START_BLOCK(sbi, segno);
 791
 792 next_step:
 793         entry = sum;
 794
 795         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 796                 struct page *data_page;
 797                 struct inode *inode;
 798                 struct node_info dni; /* dnode info for the data */
 799                 unsigned int ofs_in_node, nofs;
 800                 block_t start_bidx;
 801                 nid_t nid = le32_to_cpu(entry->nid);
 802
 803                 /* stop BG_GC if there is not enough free sections. */
 804                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 805                         return;
 806
 807                 if (check_valid_map(sbi, segno, off) == 0)
 808                         continue;
 809
 810                 if (phase == 0) {
 811                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 812                                                         META_NAT, true);
 813                         continue;
 814                 }
 815
 816                 if (phase == 1) {
 817                         ra_node_page(sbi, nid);
 818                         continue;
 819                 }
 820
 821                 /* Get an inode by ino with checking validity */
 822                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
 823                         continue;
 824
 825                 if (phase == 2) {
 826                         ra_node_page(sbi, dni.ino);
 827                         continue;
 828                 }
 829
 830                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 831
 832                 if (phase == 3) {
 833                         inode = f2fs_iget(sb, dni.ino);
 834                         if (IS_ERR(inode) || is_bad_inode(inode))
 835                                 continue;
 836
 837                         /* if encrypted inode, let's go phase 3 */
 838                         if (f2fs_encrypted_file(inode)) {
 839                                 add_gc_inode(gc_list, inode);
 840                                 continue;
 841                         }
 842
 843                         start_bidx = start_bidx_of_node(nofs, inode);
 844                         data_page = get_read_data_page(inode,
 845                                         start_bidx + ofs_in_node, REQ_RAHEAD,
 846                                         true);
 847                         if (IS_ERR(data_page)) {
 848                                 iput(inode);
 849                                 continue;
 850                         }
 851
 852                         f2fs_put_page(data_page, 0);
 853                         add_gc_inode(gc_list, inode);
 854                         continue;
 855                 }
 856
 857                 /* phase 4 */
 858                 inode = find_gc_inode(gc_list, dni.ino);
 859                 if (inode) {
 860                         struct f2fs_inode_info *fi = F2FS_I(inode);
 861                         bool locked = false;
 862
 863                         if (S_ISREG(inode->i_mode)) {
 864                                 if (!down_write_trylock(&fi->dio_rwsem[READ]))
 865                                         continue;
 866                                 if (!down_write_trylock(
 867                                                 &fi->dio_rwsem[WRITE])) {
 868                                         up_write(&fi->dio_rwsem[READ]);
 869                                         continue;
 870                                 }
 871                                 locked = true;
 872
 873                                 /* wait for all inflight aio data */
 874                                 inode_dio_wait(inode);
 875                         }
 876
 877                         start_bidx = start_bidx_of_node(nofs, inode)
 878                                                                 + ofs_in_node;
 879                         if (f2fs_encrypted_file(inode))
 880                                 move_data_block(inode, start_bidx, segno, off);
 881                         else
 882                                 move_data_page(inode, start_bidx, gc_type,
 883                                                                 segno, off);
 884
 885                         if (locked) {
 886                                 up_write(&fi->dio_rwsem[WRITE]);
 887                                 up_write(&fi->dio_rwsem[READ]);
 888                         }
 889
 890                         stat_inc_data_blk_count(sbi, 1, gc_type);
 891                 }
 892         }
 893
 894         if (++phase < 5)
 895                 goto next_step;
 896 }
 897
 898 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 899                         int gc_type)
 900 {
 901         struct sit_info *sit_i = SIT_I(sbi);
 902         int ret;
 903
 904         mutex_lock(&sit_i->sentry_lock);
 905         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
 906                                               NO_CHECK_TYPE, LFS);
 907         mutex_unlock(&sit_i->sentry_lock);
 908         return ret;
 909 }
 910
 911 static int do_garbage_collect(struct f2fs_sb_info *sbi,
 912                                 unsigned int start_segno,
 913                                 struct gc_inode_list *gc_list, int gc_type)
 914 {
 915         struct page *sum_page;
 916         struct f2fs_summary_block *sum;
 917         struct blk_plug plug;
 918         unsigned int segno = start_segno;
 919         unsigned int end_segno = start_segno + sbi->segs_per_sec;
 920         int seg_freed = 0;
 921         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 922                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
 923
 924         /* readahead multi ssa blocks those have contiguous address */
 925         if (sbi->segs_per_sec > 1)
 926                 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
 927                                         sbi->segs_per_sec, META_SSA, true);
 928
 929         /* reference all summary page */
 930         while (segno < end_segno) {
 931                 sum_page = get_sum_page(sbi, segno++);
 932                 unlock_page(sum_page);
 933         }
 934
 935         blk_start_plug(&plug);
 936
 937         for (segno = start_segno; segno < end_segno; segno++) {
 938
 939                 /* find segment summary of victim */
 940                 sum_page = find_get_page(META_MAPPING(sbi),
 941                                         GET_SUM_BLOCK(sbi, segno));
 942                 f2fs_put_page(sum_page, 0);
 943
 944                 if (get_valid_blocks(sbi, segno, false) == 0 ||
 945                                 !PageUptodate(sum_page) ||
 946                                 unlikely(f2fs_cp_error(sbi)))
 947                         goto next;
 948
 949                 sum = page_address(sum_page);
 950                 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
 951
 952                 /*
 953                  * this is to avoid deadlock:
 954                  * - lock_page(sum_page)         - f2fs_replace_block
 955                  *  - check_valid_map()            - mutex_lock(sentry_lock)
 956                  *   - mutex_lock(sentry_lock)     - change_curseg()
 957                  *                                  - lock_page(sum_page)
 958                  */
 959                 if (type == SUM_TYPE_NODE)
 960                         gc_node_segment(sbi, sum->entries, segno, gc_type);
 961                 else
 962                         gc_data_segment(sbi, sum->entries, gc_list, segno,
 963                                                                 gc_type);
 964
 965                 stat_inc_seg_count(sbi, type, gc_type);
 966
 967                 if (gc_type == FG_GC &&
 968                                 get_valid_blocks(sbi, segno, false) == 0)
 969                         seg_freed++;
 970 next:
 971                 f2fs_put_page(sum_page, 0);
 972         }
 973
 974         if (gc_type == FG_GC)
 975                 f2fs_submit_merged_write(sbi,
 976                                 (type == SUM_TYPE_NODE) ? NODE : DATA);
 977
 978         blk_finish_plug(&plug);
 979
 980         stat_inc_call_count(sbi->stat_info);
 981
 982         return seg_freed;
 983 }
 984
 985 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 986                         bool background, unsigned int segno)
 987 {
 988         int gc_type = sync ? FG_GC : BG_GC;
 989         int sec_freed = 0, seg_freed = 0, total_freed = 0;
 990         int ret = 0;
 991         struct cp_control cpc;
 992         unsigned int init_segno = segno;
 993         struct gc_inode_list gc_list = {
 994                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
 995                 .iroot = RADIX_TREE_INIT(GFP_NOFS),
 996         };
 997
 998         trace_f2fs_gc_begin(sbi->sb, sync, background,
 999                                 get_pages(sbi, F2FS_DIRTY_NODES),
1000                                 get_pages(sbi, F2FS_DIRTY_DENTS),
1001                                 get_pages(sbi, F2FS_DIRTY_IMETA),
1002                                 free_sections(sbi),
1003                                 free_segments(sbi),
1004                                 reserved_segments(sbi),
1005                                 prefree_segments(sbi));
1006
1007         cpc.reason = __get_cp_reason(sbi);
1008 gc_more:
1009         if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE))) {
1010                 ret = -EINVAL;
1011                 goto stop;
1012         }
1013         if (unlikely(f2fs_cp_error(sbi))) {
1014                 ret = -EIO;
1015                 goto stop;
1016         }
1017
1018         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1019                 /*
1020                  * For example, if there are many prefree_segments below given
1021                  * threshold, we can make them free by checkpoint. Then, we
1022                  * secure free segments which doesn't need fggc any more.
1023                  */
1024                 if (prefree_segments(sbi)) {
1025                         ret = write_checkpoint(sbi, &cpc);
1026                         if (ret)
1027                                 goto stop;
1028                 }
1029                 if (has_not_enough_free_secs(sbi, 0, 0))
1030                         gc_type = FG_GC;
1031         }
1032
1033         /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1034         if (gc_type == BG_GC && !background) {
1035                 ret = -EINVAL;
1036                 goto stop;
1037         }
1038         if (!__get_victim(sbi, &segno, gc_type)) {
1039                 ret = -ENODATA;
1040                 goto stop;
1041         }
1042
1043         seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
1044         if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
1045                 sec_freed++;
1046         total_freed += seg_freed;
1047
1048         if (gc_type == FG_GC)
1049                 sbi->cur_victim_sec = NULL_SEGNO;
1050
1051         if (!sync) {
1052                 if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1053                         segno = NULL_SEGNO;
1054                         goto gc_more;
1055                 }
1056
1057                 if (gc_type == FG_GC)
1058                         ret = write_checkpoint(sbi, &cpc);
1059         }
1060 stop:
1061         SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1062         SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1063
1064         trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1065                                 get_pages(sbi, F2FS_DIRTY_NODES),
1066                                 get_pages(sbi, F2FS_DIRTY_DENTS),
1067                                 get_pages(sbi, F2FS_DIRTY_IMETA),
1068                                 free_sections(sbi),
1069                                 free_segments(sbi),
1070                                 reserved_segments(sbi),
1071                                 prefree_segments(sbi));
1072
1073         mutex_unlock(&sbi->gc_mutex);
1074
1075         put_gc_inode(&gc_list);
1076
1077         if (sync)
1078                 ret = sec_freed ? 0 : -EAGAIN;
1079         return ret;
1080 }
1081
1082 void build_gc_manager(struct f2fs_sb_info *sbi)
1083 {
1084         u64 main_count, resv_count, ovp_count;
1085
1086         DIRTY_I(sbi)->v_ops = &default_v_ops;
1087
1088         /* threshold of # of valid blocks in a section for victims of FG_GC */
1089         main_count = SM_I(sbi)->main_segments << sbi->log_blocks_per_seg;
1090         resv_count = SM_I(sbi)->reserved_segments << sbi->log_blocks_per_seg;
1091         ovp_count = SM_I(sbi)->ovp_segments << sbi->log_blocks_per_seg;
1092
1093         sbi->fggc_threshold = div64_u64((main_count - ovp_count) *
1094                                 BLKS_PER_SEC(sbi), (main_count - resv_count));
1095
1096         /* give warm/cold data area from slower device */
1097         if (sbi->s_ndevs && sbi->segs_per_sec == 1)
1098                 SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1099                                 GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1100 }