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