fs/f2fs/gc.c

   1 /*
   2  * fs/f2fs/gc.c
   3  *
   4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
   5  *             http://www.samsung.com/
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/module.h>
  13 #include <linux/backing-dev.h>
  14 #include <linux/init.h>
  15 #include <linux/f2fs_fs.h>
  16 #include <linux/kthread.h>
  17 #include <linux/delay.h>
  18 #include <linux/freezer.h>
  19
  20 #include "f2fs.h"
  21 #include "node.h"
  22 #include "segment.h"
  23 #include "gc.h"
  24 #include <trace/events/f2fs.h>
  25
  26 static int gc_thread_func(void *data)
  27 {
  28         struct f2fs_sb_info *sbi = data;
  29         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
  30         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
  31         long wait_ms;
  32
  33         wait_ms = gc_th->min_sleep_time;
  34
  35         do {
  36                 if (try_to_freeze())
  37                         continue;
  38                 else
  39                         wait_event_interruptible_timeout(*wq,
  40                                                 kthread_should_stop(),
  41                                                 msecs_to_jiffies(wait_ms));
  42                 if (kthread_should_stop())
  43                         break;
  44
  45                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
  46                         increase_sleep_time(gc_th, &wait_ms);
  47                         continue;
  48                 }
  49
  50 #ifdef CONFIG_F2FS_FAULT_INJECTION
  51                 if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
  52                         f2fs_show_injection_info(FAULT_CHECKPOINT);
  53                         f2fs_stop_checkpoint(sbi, false);
  54                 }
  55 #endif
  56
  57                 /*
  58                  * [GC triggering condition]
  59                  * 0. GC is not conducted currently.
  60                  * 1. There are enough dirty segments.
  61                  * 2. IO subsystem is idle by checking the # of writeback pages.
  62                  * 3. IO subsystem is idle by checking the # of requests in
  63                  *    bdev's request list.
  64                  *
  65                  * Note) We have to avoid triggering GCs frequently.
  66                  * Because it is possible that some segments can be
  67                  * invalidated soon after by user update or deletion.
  68                  * So, I'd like to wait some time to collect dirty segments.
  69                  */
  70                 if (!mutex_trylock(&sbi->gc_mutex))
  71                         continue;
  72
  73                 if (!is_idle(sbi)) {
  74                         increase_sleep_time(gc_th, &wait_ms);
  75                         mutex_unlock(&sbi->gc_mutex);
  76                         continue;
  77                 }
  78
  79                 if (has_enough_invalid_blocks(sbi))
  80                         decrease_sleep_time(gc_th, &wait_ms);
  81                 else
  82                         increase_sleep_time(gc_th, &wait_ms);
  83
  84                 stat_inc_bggc_count(sbi);
  85
  86                 /* if return value is not zero, no victim was selected */
  87                 if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC), true, NULL_SEGNO))
  88                         wait_ms = gc_th->no_gc_sleep_time;
  89
  90                 trace_f2fs_background_gc(sbi->sb, wait_ms,
  91                                 prefree_segments(sbi), free_segments(sbi));
  92
  93                 /* balancing f2fs's metadata periodically */
  94                 f2fs_balance_fs_bg(sbi);
  95
  96         } while (!kthread_should_stop());
  97         return 0;
  98 }
  99
 100 int start_gc_thread(struct f2fs_sb_info *sbi)
 101 {
 102         struct f2fs_gc_kthread *gc_th;
 103         dev_t dev = sbi->sb->s_bdev->bd_dev;
 104         int err = 0;
 105
 106         gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
 107         if (!gc_th) {
 108                 err = -ENOMEM;
 109                 goto out;
 110         }
 111
 112         gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
 113         gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
 114         gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
 115
 116         gc_th->gc_idle = 0;
 117
 118         sbi->gc_thread = gc_th;
 119         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
 120         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
 121                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
 122         if (IS_ERR(gc_th->f2fs_gc_task)) {
 123                 err = PTR_ERR(gc_th->f2fs_gc_task);
 124                 kfree(gc_th);
 125                 sbi->gc_thread = NULL;
 126         }
 127 out:
 128         return err;
 129 }
 130
 131 void stop_gc_thread(struct f2fs_sb_info *sbi)
 132 {
 133         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 134         if (!gc_th)
 135                 return;
 136         kthread_stop(gc_th->f2fs_gc_task);
 137         kfree(gc_th);
 138         sbi->gc_thread = NULL;
 139 }
 140
 141 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
 142 {
 143         int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
 144
 145         if (gc_th && gc_th->gc_idle) {
 146                 if (gc_th->gc_idle == 1)
 147                         gc_mode = GC_CB;
 148                 else if (gc_th->gc_idle == 2)
 149                         gc_mode = GC_GREEDY;
 150         }
 151         return gc_mode;
 152 }
 153
 154 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
 155                         int type, struct victim_sel_policy *p)
 156 {
 157         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 158
 159         if (p->alloc_mode == SSR) {
 160                 p->gc_mode = GC_GREEDY;
 161                 p->dirty_segmap = dirty_i->dirty_segmap[type];
 162                 p->max_search = dirty_i->nr_dirty[type];
 163                 p->ofs_unit = 1;
 164         } else {
 165                 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
 166                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
 167                 p->max_search = dirty_i->nr_dirty[DIRTY];
 168                 p->ofs_unit = sbi->segs_per_sec;
 169         }
 170
 171         /* we need to check every dirty segments in the FG_GC case */
 172         if (gc_type != FG_GC && p->max_search > sbi->max_victim_search)
 173                 p->max_search = sbi->max_victim_search;
 174
 175         /* let's select beginning hot/small space first */
 176         if (type == CURSEG_HOT_DATA || IS_NODESEG(type))
 177                 p->offset = 0;
 178         else
 179                 p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
 180 }
 181
 182 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 183                                 struct victim_sel_policy *p)
 184 {
 185         /* SSR allocates in a segment unit */
 186         if (p->alloc_mode == SSR)
 187                 return sbi->blocks_per_seg;
 188         if (p->gc_mode == GC_GREEDY)
 189                 return 2 * sbi->blocks_per_seg * p->ofs_unit;
 190         else if (p->gc_mode == GC_CB)
 191                 return UINT_MAX;
 192         else /* No other gc_mode */
 193                 return 0;
 194 }
 195
 196 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 197 {
 198         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 199         unsigned int secno;
 200
 201         /*
 202          * If the gc_type is FG_GC, we can select victim segments
 203          * selected by background GC before.
 204          * Those segments guarantee they have small valid blocks.
 205          */
 206         for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
 207                 if (sec_usage_check(sbi, secno))
 208                         continue;
 209
 210                 if (no_fggc_candidate(sbi, secno))
 211                         continue;
 212
 213                 clear_bit(secno, dirty_i->victim_secmap);
 214                 return GET_SEG_FROM_SEC(sbi, secno);
 215         }
 216         return NULL_SEGNO;
 217 }
 218
 219 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 220 {
 221         struct sit_info *sit_i = SIT_I(sbi);
 222         unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
 223         unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
 224         unsigned long long mtime = 0;
 225         unsigned int vblocks;
 226         unsigned char age = 0;
 227         unsigned char u;
 228         unsigned int i;
 229
 230         for (i = 0; i < sbi->segs_per_sec; i++)
 231                 mtime += get_seg_entry(sbi, start + i)->mtime;
 232         vblocks = get_valid_blocks(sbi, segno, true);
 233
 234         mtime = div_u64(mtime, sbi->segs_per_sec);
 235         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 236
 237         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 238
 239         /* Handle if the system time has changed by the user */
 240         if (mtime < sit_i->min_mtime)
 241                 sit_i->min_mtime = mtime;
 242         if (mtime > sit_i->max_mtime)
 243                 sit_i->max_mtime = mtime;
 244         if (sit_i->max_mtime != sit_i->min_mtime)
 245                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 246                                 sit_i->max_mtime - sit_i->min_mtime);
 247
 248         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 249 }
 250
 251 static unsigned int get_greedy_cost(struct f2fs_sb_info *sbi,
 252                                                 unsigned int segno)
 253 {
 254         unsigned int valid_blocks =
 255                         get_valid_blocks(sbi, segno, true);
 256
 257         return IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 258                                 valid_blocks * 2 : valid_blocks;
 259 }
 260
 261 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 262                         unsigned int segno, struct victim_sel_policy *p)
 263 {
 264         if (p->alloc_mode == SSR)
 265                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 266
 267         /* alloc_mode == LFS */
 268         if (p->gc_mode == GC_GREEDY)
 269                 return get_greedy_cost(sbi, segno);
 270         else
 271                 return get_cb_cost(sbi, segno);
 272 }
 273
 274 static unsigned int count_bits(const unsigned long *addr,
 275                                 unsigned int offset, unsigned int len)
 276 {
 277         unsigned int end = offset + len, sum = 0;
 278
 279         while (offset < end) {
 280                 if (test_bit(offset++, addr))
 281                         ++sum;
 282         }
 283         return sum;
 284 }
 285
 286 /*
 287  * This function is called from two paths.
 288  * One is garbage collection and the other is SSR segment selection.
 289  * When it is called during GC, it just gets a victim segment
 290  * and it does not remove it from dirty seglist.
 291  * When it is called from SSR segment selection, it finds a segment
 292  * which has minimum valid blocks and removes it from dirty seglist.
 293  */
 294 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 295                 unsigned int *result, int gc_type, int type, char alloc_mode)
 296 {
 297         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 298         struct sit_info *sm = SIT_I(sbi);
 299         struct victim_sel_policy p;
 300         unsigned int secno, last_victim;
 301         unsigned int last_segment = MAIN_SEGS(sbi);
 302         unsigned int nsearched = 0;
 303
 304         mutex_lock(&dirty_i->seglist_lock);
 305
 306         p.alloc_mode = alloc_mode;
 307         select_policy(sbi, gc_type, type, &p);
 308
 309         p.min_segno = NULL_SEGNO;
 310         p.min_cost = get_max_cost(sbi, &p);
 311
 312         if (*result != NULL_SEGNO) {
 313                 if (IS_DATASEG(get_seg_entry(sbi, *result)->type) &&
 314                         get_valid_blocks(sbi, *result, false) &&
 315                         !sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
 316                         p.min_segno = *result;
 317                 goto out;
 318         }
 319
 320         if (p.max_search == 0)
 321                 goto out;
 322
 323         last_victim = sm->last_victim[p.gc_mode];
 324         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 325                 p.min_segno = check_bg_victims(sbi);
 326                 if (p.min_segno != NULL_SEGNO)
 327                         goto got_it;
 328         }
 329
 330         while (1) {
 331                 unsigned long cost;
 332                 unsigned int segno;
 333
 334                 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
 335                 if (segno >= last_segment) {
 336                         if (sm->last_victim[p.gc_mode]) {
 337                                 last_segment =
 338                                         sm->last_victim[p.gc_mode];
 339                                 sm->last_victim[p.gc_mode] = 0;
 340                                 p.offset = 0;
 341                                 continue;
 342                         }
 343                         break;
 344                 }
 345
 346                 p.offset = segno + p.ofs_unit;
 347                 if (p.ofs_unit > 1) {
 348                         p.offset -= segno % p.ofs_unit;
 349                         nsearched += count_bits(p.dirty_segmap,
 350                                                 p.offset - p.ofs_unit,
 351                                                 p.ofs_unit);
 352                 } else {
 353                         nsearched++;
 354                 }
 355
 356                 secno = GET_SEC_FROM_SEG(sbi, segno);
 357
 358                 if (sec_usage_check(sbi, secno))
 359                         goto next;
 360                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 361                         goto next;
 362                 if (gc_type == FG_GC && p.alloc_mode == LFS &&
 363                                         no_fggc_candidate(sbi, secno))
 364                         goto next;
 365
 366                 cost = get_gc_cost(sbi, segno, &p);
 367
 368                 if (p.min_cost > cost) {
 369                         p.min_segno = segno;
 370                         p.min_cost = cost;
 371                 }
 372 next:
 373                 if (nsearched >= p.max_search) {
 374                         if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
 375                                 sm->last_victim[p.gc_mode] = last_victim + 1;
 376                         else
 377                                 sm->last_victim[p.gc_mode] = segno + 1;
 378                         sm->last_victim[p.gc_mode] %= MAIN_SEGS(sbi);
 379                         break;
 380                 }
 381         }
 382         if (p.min_segno != NULL_SEGNO) {
 383 got_it:
 384                 if (p.alloc_mode == LFS) {
 385                         secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
 386                         if (gc_type == FG_GC)
 387                                 sbi->cur_victim_sec = secno;
 388                         else
 389                                 set_bit(secno, dirty_i->victim_secmap);
 390                 }
 391                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 392
 393                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 394                                 sbi->cur_victim_sec,
 395                                 prefree_segments(sbi), free_segments(sbi));
 396         }
 397 out:
 398         mutex_unlock(&dirty_i->seglist_lock);
 399
 400         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 401 }
 402
 403 static const struct victim_selection default_v_ops = {
 404         .get_victim = get_victim_by_default,
 405 };
 406
 407 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 408 {
 409         struct inode_entry *ie;
 410
 411         ie = radix_tree_lookup(&gc_list->iroot, ino);
 412         if (ie)
 413                 return ie->inode;
 414         return NULL;
 415 }
 416
 417 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 418 {
 419         struct inode_entry *new_ie;
 420
 421         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
 422                 iput(inode);
 423                 return;
 424         }
 425         new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
 426         new_ie->inode = inode;
 427
 428         f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
 429         list_add_tail(&new_ie->list, &gc_list->ilist);
 430 }
 431
 432 static void put_gc_inode(struct gc_inode_list *gc_list)
 433 {
 434         struct inode_entry *ie, *next_ie;
 435         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
 436                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
 437                 iput(ie->inode);
 438                 list_del(&ie->list);
 439                 kmem_cache_free(inode_entry_slab, ie);
 440         }
 441 }
 442
 443 static int check_valid_map(struct f2fs_sb_info *sbi,
 444                                 unsigned int segno, int offset)
 445 {
 446         struct sit_info *sit_i = SIT_I(sbi);
 447         struct seg_entry *sentry;
 448         int ret;
 449
 450         mutex_lock(&sit_i->sentry_lock);
 451         sentry = get_seg_entry(sbi, segno);
 452         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 453         mutex_unlock(&sit_i->sentry_lock);
 454         return ret;
 455 }
 456
 457 /*
 458  * This function compares node address got in summary with that in NAT.
 459  * On validity, copy that node with cold status, otherwise (invalid node)
 460  * ignore that.
 461  */
 462 static void gc_node_segment(struct f2fs_sb_info *sbi,
 463                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 464 {
 465         struct f2fs_summary *entry;
 466         block_t start_addr;
 467         int off;
 468         int phase = 0;
 469
 470         start_addr = START_BLOCK(sbi, segno);
 471
 472 next_step:
 473         entry = sum;
 474
 475         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 476                 nid_t nid = le32_to_cpu(entry->nid);
 477                 struct page *node_page;
 478                 struct node_info ni;
 479
 480                 /* stop BG_GC if there is not enough free sections. */
 481                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 482                         return;
 483
 484                 if (check_valid_map(sbi, segno, off) == 0)
 485                         continue;
 486
 487                 if (phase == 0) {
 488                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 489                                                         META_NAT, true);
 490                         continue;
 491                 }
 492
 493                 if (phase == 1) {
 494                         ra_node_page(sbi, nid);
 495                         continue;
 496                 }
 497
 498                 /* phase == 2 */
 499                 node_page = get_node_page(sbi, nid);
 500                 if (IS_ERR(node_page))
 501                         continue;
 502
 503                 /* block may become invalid during get_node_page */
 504                 if (check_valid_map(sbi, segno, off) == 0) {
 505                         f2fs_put_page(node_page, 1);
 506                         continue;
 507                 }
 508
 509                 get_node_info(sbi, nid, &ni);
 510                 if (ni.blk_addr != start_addr + off) {
 511                         f2fs_put_page(node_page, 1);
 512                         continue;
 513                 }
 514
 515                 move_node_page(node_page, gc_type);
 516                 stat_inc_node_blk_count(sbi, 1, gc_type);
 517         }
 518
 519         if (++phase < 3)
 520                 goto next_step;
 521 }
 522
 523 /*
 524  * Calculate start block index indicating the given node offset.
 525  * Be careful, caller should give this node offset only indicating direct node
 526  * blocks. If any node offsets, which point the other types of node blocks such
 527  * as indirect or double indirect node blocks, are given, it must be a caller's
 528  * bug.
 529  */
 530 block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
 531 {
 532         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 533         unsigned int bidx;
 534
 535         if (node_ofs == 0)
 536                 return 0;
 537
 538         if (node_ofs <= 2) {
 539                 bidx = node_ofs - 1;
 540         } else if (node_ofs <= indirect_blks) {
 541                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 542                 bidx = node_ofs - 2 - dec;
 543         } else {
 544                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 545                 bidx = node_ofs - 5 - dec;
 546         }
 547         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
 548 }
 549
 550 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 551                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 552 {
 553         struct page *node_page;
 554         nid_t nid;
 555         unsigned int ofs_in_node;
 556         block_t source_blkaddr;
 557
 558         nid = le32_to_cpu(sum->nid);
 559         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 560
 561         node_page = get_node_page(sbi, nid);
 562         if (IS_ERR(node_page))
 563                 return false;
 564
 565         get_node_info(sbi, nid, dni);
 566
 567         if (sum->version != dni->version) {
 568                 f2fs_msg(sbi->sb, KERN_WARNING,
 569                                 "%s: valid data with mismatched node version.",
 570                                 __func__);
 571                 set_sbi_flag(sbi, SBI_NEED_FSCK);
 572         }
 573
 574         *nofs = ofs_of_node(node_page);
 575         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 576         f2fs_put_page(node_page, 1);
 577
 578         if (source_blkaddr != blkaddr)
 579                 return false;
 580         return true;
 581 }
 582
 583 static void move_encrypted_block(struct inode *inode, block_t bidx,
 584                                                         unsigned int segno, int off)
 585 {
 586         struct f2fs_io_info fio = {
 587                 .sbi = F2FS_I_SB(inode),
 588                 .type = DATA,
 589                 .op = REQ_OP_READ,
 590                 .op_flags = 0,
 591                 .encrypted_page = NULL,
 592         };
 593         struct dnode_of_data dn;
 594         struct f2fs_summary sum;
 595         struct node_info ni;
 596         struct page *page;
 597         block_t newaddr;
 598         int err;
 599
 600         /* do not read out */
 601         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 602         if (!page)
 603                 return;
 604
 605         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 606                 goto out;
 607
 608         if (f2fs_is_atomic_file(inode))
 609                 goto out;
 610
 611         set_new_dnode(&dn, inode, NULL, NULL, 0);
 612         err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
 613         if (err)
 614                 goto out;
 615
 616         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 617                 ClearPageUptodate(page);
 618                 goto put_out;
 619         }
 620
 621         /*
 622          * don't cache encrypted data into meta inode until previous dirty
 623          * data were writebacked to avoid racing between GC and flush.
 624          */
 625         f2fs_wait_on_page_writeback(page, DATA, true);
 626
 627         get_node_info(fio.sbi, dn.nid, &ni);
 628         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
 629
 630         /* read page */
 631         fio.page = page;
 632         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 633
 634         allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 635                                                         &sum, CURSEG_COLD_DATA);
 636
 637         fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
 638                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
 639         if (!fio.encrypted_page) {
 640                 err = -ENOMEM;
 641                 goto recover_block;
 642         }
 643
 644         err = f2fs_submit_page_bio(&fio);
 645         if (err)
 646                 goto put_page_out;
 647
 648         /* write page */
 649         lock_page(fio.encrypted_page);
 650
 651         if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
 652                 err = -EIO;
 653                 goto put_page_out;
 654         }
 655         if (unlikely(!PageUptodate(fio.encrypted_page))) {
 656                 err = -EIO;
 657                 goto put_page_out;
 658         }
 659
 660         set_page_dirty(fio.encrypted_page);
 661         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
 662         if (clear_page_dirty_for_io(fio.encrypted_page))
 663                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
 664
 665         set_page_writeback(fio.encrypted_page);
 666
 667         /* allocate block address */
 668         f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
 669
 670         fio.op = REQ_OP_WRITE;
 671         fio.op_flags = REQ_SYNC;
 672         fio.new_blkaddr = newaddr;
 673         f2fs_submit_page_mbio(&fio);
 674
 675         f2fs_update_data_blkaddr(&dn, newaddr);
 676         set_inode_flag(inode, FI_APPEND_WRITE);
 677         if (page->index == 0)
 678                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 679 put_page_out:
 680         f2fs_put_page(fio.encrypted_page, 1);
 681 recover_block:
 682         if (err)
 683                 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
 684                                                                 true, true);
 685 put_out:
 686         f2fs_put_dnode(&dn);
 687 out:
 688         f2fs_put_page(page, 1);
 689 }
 690
 691 static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
 692                                                         unsigned int segno, int off)
 693 {
 694         struct page *page;
 695
 696         page = get_lock_data_page(inode, bidx, true);
 697         if (IS_ERR(page))
 698                 return;
 699
 700         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
 701                 goto out;
 702
 703         if (f2fs_is_atomic_file(inode))
 704                 goto out;
 705
 706         if (gc_type == BG_GC) {
 707                 if (PageWriteback(page))
 708                         goto out;
 709                 set_page_dirty(page);
 710                 set_cold_data(page);
 711         } else {
 712                 struct f2fs_io_info fio = {
 713                         .sbi = F2FS_I_SB(inode),
 714                         .type = DATA,
 715                         .op = REQ_OP_WRITE,
 716                         .op_flags = REQ_SYNC,
 717                         .old_blkaddr = NULL_ADDR,
 718                         .page = page,
 719                         .encrypted_page = NULL,
 720                         .need_lock = true,
 721                 };
 722                 bool is_dirty = PageDirty(page);
 723                 int err;
 724
 725 retry:
 726                 set_page_dirty(page);
 727                 f2fs_wait_on_page_writeback(page, DATA, true);
 728                 if (clear_page_dirty_for_io(page)) {
 729                         inode_dec_dirty_pages(inode);
 730                         remove_dirty_inode(inode);
 731                 }
 732
 733                 set_cold_data(page);
 734
 735                 err = do_write_data_page(&fio);
 736                 if (err == -ENOMEM && is_dirty) {
 737                         congestion_wait(BLK_RW_ASYNC, HZ/50);
 738                         goto retry;
 739                 }
 740         }
 741 out:
 742         f2fs_put_page(page, 1);
 743 }
 744
 745 /*
 746  * This function tries to get parent node of victim data block, and identifies
 747  * data block validity. If the block is valid, copy that with cold status and
 748  * modify parent node.
 749  * If the parent node is not valid or the data block address is different,
 750  * the victim data block is ignored.
 751  */
 752 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 753                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 754 {
 755         struct super_block *sb = sbi->sb;
 756         struct f2fs_summary *entry;
 757         block_t start_addr;
 758         int off;
 759         int phase = 0;
 760
 761         start_addr = START_BLOCK(sbi, segno);
 762
 763 next_step:
 764         entry = sum;
 765
 766         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 767                 struct page *data_page;
 768                 struct inode *inode;
 769                 struct node_info dni; /* dnode info for the data */
 770                 unsigned int ofs_in_node, nofs;
 771                 block_t start_bidx;
 772                 nid_t nid = le32_to_cpu(entry->nid);
 773
 774                 /* stop BG_GC if there is not enough free sections. */
 775                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 776                         return;
 777
 778                 if (check_valid_map(sbi, segno, off) == 0)
 779                         continue;
 780
 781                 if (phase == 0) {
 782                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 783                                                         META_NAT, true);
 784                         continue;
 785                 }
 786
 787                 if (phase == 1) {
 788                         ra_node_page(sbi, nid);
 789                         continue;
 790                 }
 791
 792                 /* Get an inode by ino with checking validity */
 793                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
 794                         continue;
 795
 796                 if (phase == 2) {
 797                         ra_node_page(sbi, dni.ino);
 798                         continue;
 799                 }
 800
 801                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 802
 803                 if (phase == 3) {
 804                         inode = f2fs_iget(sb, dni.ino);
 805                         if (IS_ERR(inode) || is_bad_inode(inode))
 806                                 continue;
 807
 808                         /* if encrypted inode, let's go phase 3 */
 809                         if (f2fs_encrypted_inode(inode) &&
 810                                                 S_ISREG(inode->i_mode)) {
 811                                 add_gc_inode(gc_list, inode);
 812                                 continue;
 813                         }
 814
 815                         start_bidx = start_bidx_of_node(nofs, inode);
 816                         data_page = get_read_data_page(inode,
 817                                         start_bidx + ofs_in_node, REQ_RAHEAD,
 818                                         true);
 819                         if (IS_ERR(data_page)) {
 820                                 iput(inode);
 821                                 continue;
 822                         }
 823
 824                         f2fs_put_page(data_page, 0);
 825                         add_gc_inode(gc_list, inode);
 826                         continue;
 827                 }
 828
 829                 /* phase 4 */
 830                 inode = find_gc_inode(gc_list, dni.ino);
 831                 if (inode) {
 832                         struct f2fs_inode_info *fi = F2FS_I(inode);
 833                         bool locked = false;
 834
 835                         if (S_ISREG(inode->i_mode)) {
 836                                 if (!down_write_trylock(&fi->dio_rwsem[READ]))
 837                                         continue;
 838                                 if (!down_write_trylock(
 839                                                 &fi->dio_rwsem[WRITE])) {
 840                                         up_write(&fi->dio_rwsem[READ]);
 841                                         continue;
 842                                 }
 843                                 locked = true;
 844                         }
 845
 846                         start_bidx = start_bidx_of_node(nofs, inode)
 847                                                                 + ofs_in_node;
 848                         if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
 849                                 move_encrypted_block(inode, start_bidx, segno, off);
 850                         else
 851                                 move_data_page(inode, start_bidx, gc_type, segno, off);
 852
 853                         if (locked) {
 854                                 up_write(&fi->dio_rwsem[WRITE]);
 855                                 up_write(&fi->dio_rwsem[READ]);
 856                         }
 857
 858                         stat_inc_data_blk_count(sbi, 1, gc_type);
 859                 }
 860         }
 861
 862         if (++phase < 5)
 863                 goto next_step;
 864 }
 865
 866 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 867                         int gc_type)
 868 {
 869         struct sit_info *sit_i = SIT_I(sbi);
 870         int ret;
 871
 872         mutex_lock(&sit_i->sentry_lock);
 873         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
 874                                               NO_CHECK_TYPE, LFS);
 875         mutex_unlock(&sit_i->sentry_lock);
 876         return ret;
 877 }
 878
 879 static int do_garbage_collect(struct f2fs_sb_info *sbi,
 880                                 unsigned int start_segno,
 881                                 struct gc_inode_list *gc_list, int gc_type)
 882 {
 883         struct page *sum_page;
 884         struct f2fs_summary_block *sum;
 885         struct blk_plug plug;
 886         unsigned int segno = start_segno;
 887         unsigned int end_segno = start_segno + sbi->segs_per_sec;
 888         int sec_freed = 0;
 889         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 890                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
 891
 892         /* readahead multi ssa blocks those have contiguous address */
 893         if (sbi->segs_per_sec > 1)
 894                 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
 895                                         sbi->segs_per_sec, META_SSA, true);
 896
 897         /* reference all summary page */
 898         while (segno < end_segno) {
 899                 sum_page = get_sum_page(sbi, segno++);
 900                 unlock_page(sum_page);
 901         }
 902
 903         blk_start_plug(&plug);
 904
 905         for (segno = start_segno; segno < end_segno; segno++) {
 906
 907                 /* find segment summary of victim */
 908                 sum_page = find_get_page(META_MAPPING(sbi),
 909                                         GET_SUM_BLOCK(sbi, segno));
 910                 f2fs_put_page(sum_page, 0);
 911
 912                 if (get_valid_blocks(sbi, segno, false) == 0 ||
 913                                 !PageUptodate(sum_page) ||
 914                                 unlikely(f2fs_cp_error(sbi)))
 915                         goto next;
 916
 917                 sum = page_address(sum_page);
 918                 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
 919
 920                 /*
 921                  * this is to avoid deadlock:
 922                  * - lock_page(sum_page)         - f2fs_replace_block
 923                  *  - check_valid_map()            - mutex_lock(sentry_lock)
 924                  *   - mutex_lock(sentry_lock)     - change_curseg()
 925                  *                                  - lock_page(sum_page)
 926                  */
 927                 if (type == SUM_TYPE_NODE)
 928                         gc_node_segment(sbi, sum->entries, segno, gc_type);
 929                 else
 930                         gc_data_segment(sbi, sum->entries, gc_list, segno,
 931                                                                 gc_type);
 932
 933                 stat_inc_seg_count(sbi, type, gc_type);
 934 next:
 935                 f2fs_put_page(sum_page, 0);
 936         }
 937
 938         if (gc_type == FG_GC)
 939                 f2fs_submit_merged_bio(sbi,
 940                                 (type == SUM_TYPE_NODE) ? NODE : DATA, WRITE);
 941
 942         blk_finish_plug(&plug);
 943
 944         if (gc_type == FG_GC &&
 945                 get_valid_blocks(sbi, start_segno, true) == 0)
 946                 sec_freed = 1;
 947
 948         stat_inc_call_count(sbi->stat_info);
 949
 950         return sec_freed;
 951 }
 952
 953 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
 954                         bool background, unsigned int segno)
 955 {
 956         int gc_type = sync ? FG_GC : BG_GC;
 957         int sec_freed = 0;
 958         int ret = -EINVAL;
 959         struct cp_control cpc;
 960         unsigned int init_segno = segno;
 961         struct gc_inode_list gc_list = {
 962                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
 963                 .iroot = RADIX_TREE_INIT(GFP_NOFS),
 964         };
 965
 966         cpc.reason = __get_cp_reason(sbi);
 967 gc_more:
 968         if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
 969                 goto stop;
 970         if (unlikely(f2fs_cp_error(sbi))) {
 971                 ret = -EIO;
 972                 goto stop;
 973         }
 974
 975         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
 976                 /*
 977                  * For example, if there are many prefree_segments below given
 978                  * threshold, we can make them free by checkpoint. Then, we
 979                  * secure free segments which doesn't need fggc any more.
 980                  */
 981                 if (prefree_segments(sbi)) {
 982                         ret = write_checkpoint(sbi, &cpc);
 983                         if (ret)
 984                                 goto stop;
 985                 }
 986                 if (has_not_enough_free_secs(sbi, 0, 0))
 987                         gc_type = FG_GC;
 988         }
 989
 990         /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
 991         if (gc_type == BG_GC && !background)
 992                 goto stop;
 993         if (!__get_victim(sbi, &segno, gc_type))
 994                 goto stop;
 995         ret = 0;
 996
 997         if (do_garbage_collect(sbi, segno, &gc_list, gc_type) &&
 998                         gc_type == FG_GC)
 999                 sec_freed++;
1000
1001         if (gc_type == FG_GC)
1002                 sbi->cur_victim_sec = NULL_SEGNO;
1003
1004         if (!sync) {
1005                 if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1006                         segno = NULL_SEGNO;
1007                         goto gc_more;
1008                 }
1009
1010                 if (gc_type == FG_GC)
1011                         ret = write_checkpoint(sbi, &cpc);
1012         }
1013 stop:
1014         SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1015         SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1016         mutex_unlock(&sbi->gc_mutex);
1017
1018         put_gc_inode(&gc_list);
1019
1020         if (sync)
1021                 ret = sec_freed ? 0 : -EAGAIN;
1022         return ret;
1023 }
1024
1025 void build_gc_manager(struct f2fs_sb_info *sbi)
1026 {
1027         u64 main_count, resv_count, ovp_count;
1028
1029         DIRTY_I(sbi)->v_ops = &default_v_ops;
1030
1031         /* threshold of # of valid blocks in a section for victims of FG_GC */
1032         main_count = SM_I(sbi)->main_segments << sbi->log_blocks_per_seg;
1033         resv_count = SM_I(sbi)->reserved_segments << sbi->log_blocks_per_seg;
1034         ovp_count = SM_I(sbi)->ovp_segments << sbi->log_blocks_per_seg;
1035
1036         sbi->fggc_threshold = div64_u64((main_count - ovp_count) *
1037                                 BLKS_PER_SEC(sbi), (main_count - resv_count));
1038
1039         /* give warm/cold data area from slower device */
1040         if (sbi->s_ndevs && sbi->segs_per_sec == 1)
1041                 SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1042                                 GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1043 }