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         if (p->max_search > sbi->max_victim_search)
 170                 p->max_search = sbi->max_victim_search;
 171
 172         p->offset = sbi->last_victim[p->gc_mode];
 173 }
 174
 175 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
 176                                 struct victim_sel_policy *p)
 177 {
 178         /* SSR allocates in a segment unit */
 179         if (p->alloc_mode == SSR)
 180                 return sbi->blocks_per_seg;
 181         if (p->gc_mode == GC_GREEDY)
 182                 return sbi->blocks_per_seg * p->ofs_unit;
 183         else if (p->gc_mode == GC_CB)
 184                 return UINT_MAX;
 185         else /* No other gc_mode */
 186                 return 0;
 187 }
 188
 189 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
 190 {
 191         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 192         unsigned int secno;
 193
 194         /*
 195          * If the gc_type is FG_GC, we can select victim segments
 196          * selected by background GC before.
 197          * Those segments guarantee they have small valid blocks.
 198          */
 199         for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
 200                 if (sec_usage_check(sbi, secno))
 201                         continue;
 202                 clear_bit(secno, dirty_i->victim_secmap);
 203                 return secno * sbi->segs_per_sec;
 204         }
 205         return NULL_SEGNO;
 206 }
 207
 208 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
 209 {
 210         struct sit_info *sit_i = SIT_I(sbi);
 211         unsigned int secno = GET_SECNO(sbi, segno);
 212         unsigned int start = secno * sbi->segs_per_sec;
 213         unsigned long long mtime = 0;
 214         unsigned int vblocks;
 215         unsigned char age = 0;
 216         unsigned char u;
 217         unsigned int i;
 218
 219         for (i = 0; i < sbi->segs_per_sec; i++)
 220                 mtime += get_seg_entry(sbi, start + i)->mtime;
 221         vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 222
 223         mtime = div_u64(mtime, sbi->segs_per_sec);
 224         vblocks = div_u64(vblocks, sbi->segs_per_sec);
 225
 226         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
 227
 228         /* Handle if the system time has changed by the user */
 229         if (mtime < sit_i->min_mtime)
 230                 sit_i->min_mtime = mtime;
 231         if (mtime > sit_i->max_mtime)
 232                 sit_i->max_mtime = mtime;
 233         if (sit_i->max_mtime != sit_i->min_mtime)
 234                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
 235                                 sit_i->max_mtime - sit_i->min_mtime);
 236
 237         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
 238 }
 239
 240 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
 241                         unsigned int segno, struct victim_sel_policy *p)
 242 {
 243         if (p->alloc_mode == SSR)
 244                 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
 245
 246         /* alloc_mode == LFS */
 247         if (p->gc_mode == GC_GREEDY)
 248                 return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
 249         else
 250                 return get_cb_cost(sbi, segno);
 251 }
 252
 253 static unsigned int count_bits(const unsigned long *addr,
 254                                 unsigned int offset, unsigned int len)
 255 {
 256         unsigned int end = offset + len, sum = 0;
 257
 258         while (offset < end) {
 259                 if (test_bit(offset++, addr))
 260                         ++sum;
 261         }
 262         return sum;
 263 }
 264
 265 /*
 266  * This function is called from two paths.
 267  * One is garbage collection and the other is SSR segment selection.
 268  * When it is called during GC, it just gets a victim segment
 269  * and it does not remove it from dirty seglist.
 270  * When it is called from SSR segment selection, it finds a segment
 271  * which has minimum valid blocks and removes it from dirty seglist.
 272  */
 273 static int get_victim_by_default(struct f2fs_sb_info *sbi,
 274                 unsigned int *result, int gc_type, int type, char alloc_mode)
 275 {
 276         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
 277         struct victim_sel_policy p;
 278         unsigned int secno, last_victim;
 279         unsigned int last_segment = MAIN_SEGS(sbi);
 280         unsigned int nsearched = 0;
 281
 282         mutex_lock(&dirty_i->seglist_lock);
 283
 284         p.alloc_mode = alloc_mode;
 285         select_policy(sbi, gc_type, type, &p);
 286
 287         p.min_segno = NULL_SEGNO;
 288         p.min_cost = get_max_cost(sbi, &p);
 289
 290         if (p.max_search == 0)
 291                 goto out;
 292
 293         last_victim = sbi->last_victim[p.gc_mode];
 294         if (p.alloc_mode == LFS && gc_type == FG_GC) {
 295                 p.min_segno = check_bg_victims(sbi);
 296                 if (p.min_segno != NULL_SEGNO)
 297                         goto got_it;
 298         }
 299
 300         while (1) {
 301                 unsigned long cost;
 302                 unsigned int segno;
 303
 304                 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
 305                 if (segno >= last_segment) {
 306                         if (sbi->last_victim[p.gc_mode]) {
 307                                 last_segment = sbi->last_victim[p.gc_mode];
 308                                 sbi->last_victim[p.gc_mode] = 0;
 309                                 p.offset = 0;
 310                                 continue;
 311                         }
 312                         break;
 313                 }
 314
 315                 p.offset = segno + p.ofs_unit;
 316                 if (p.ofs_unit > 1) {
 317                         p.offset -= segno % p.ofs_unit;
 318                         nsearched += count_bits(p.dirty_segmap,
 319                                                 p.offset - p.ofs_unit,
 320                                                 p.ofs_unit);
 321                 } else {
 322                         nsearched++;
 323                 }
 324
 325
 326                 secno = GET_SECNO(sbi, segno);
 327
 328                 if (sec_usage_check(sbi, secno))
 329                         goto next;
 330                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
 331                         goto next;
 332
 333                 cost = get_gc_cost(sbi, segno, &p);
 334
 335                 if (p.min_cost > cost) {
 336                         p.min_segno = segno;
 337                         p.min_cost = cost;
 338                 }
 339 next:
 340                 if (nsearched >= p.max_search) {
 341                         if (!sbi->last_victim[p.gc_mode] && segno <= last_victim)
 342                                 sbi->last_victim[p.gc_mode] = last_victim + 1;
 343                         else
 344                                 sbi->last_victim[p.gc_mode] = segno + 1;
 345                         break;
 346                 }
 347         }
 348         if (p.min_segno != NULL_SEGNO) {
 349 got_it:
 350                 if (p.alloc_mode == LFS) {
 351                         secno = GET_SECNO(sbi, p.min_segno);
 352                         if (gc_type == FG_GC)
 353                                 sbi->cur_victim_sec = secno;
 354                         else
 355                                 set_bit(secno, dirty_i->victim_secmap);
 356                 }
 357                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
 358
 359                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
 360                                 sbi->cur_victim_sec,
 361                                 prefree_segments(sbi), free_segments(sbi));
 362         }
 363 out:
 364         mutex_unlock(&dirty_i->seglist_lock);
 365
 366         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
 367 }
 368
 369 static const struct victim_selection default_v_ops = {
 370         .get_victim = get_victim_by_default,
 371 };
 372
 373 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
 374 {
 375         struct inode_entry *ie;
 376
 377         ie = radix_tree_lookup(&gc_list->iroot, ino);
 378         if (ie)
 379                 return ie->inode;
 380         return NULL;
 381 }
 382
 383 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
 384 {
 385         struct inode_entry *new_ie;
 386
 387         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
 388                 iput(inode);
 389                 return;
 390         }
 391         new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
 392         new_ie->inode = inode;
 393
 394         f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
 395         list_add_tail(&new_ie->list, &gc_list->ilist);
 396 }
 397
 398 static void put_gc_inode(struct gc_inode_list *gc_list)
 399 {
 400         struct inode_entry *ie, *next_ie;
 401         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
 402                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
 403                 iput(ie->inode);
 404                 list_del(&ie->list);
 405                 kmem_cache_free(inode_entry_slab, ie);
 406         }
 407 }
 408
 409 static int check_valid_map(struct f2fs_sb_info *sbi,
 410                                 unsigned int segno, int offset)
 411 {
 412         struct sit_info *sit_i = SIT_I(sbi);
 413         struct seg_entry *sentry;
 414         int ret;
 415
 416         mutex_lock(&sit_i->sentry_lock);
 417         sentry = get_seg_entry(sbi, segno);
 418         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
 419         mutex_unlock(&sit_i->sentry_lock);
 420         return ret;
 421 }
 422
 423 /*
 424  * This function compares node address got in summary with that in NAT.
 425  * On validity, copy that node with cold status, otherwise (invalid node)
 426  * ignore that.
 427  */
 428 static void gc_node_segment(struct f2fs_sb_info *sbi,
 429                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
 430 {
 431         struct f2fs_summary *entry;
 432         block_t start_addr;
 433         int off;
 434         int phase = 0;
 435
 436         start_addr = START_BLOCK(sbi, segno);
 437
 438 next_step:
 439         entry = sum;
 440
 441         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 442                 nid_t nid = le32_to_cpu(entry->nid);
 443                 struct page *node_page;
 444                 struct node_info ni;
 445
 446                 /* stop BG_GC if there is not enough free sections. */
 447                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 448                         return;
 449
 450                 if (check_valid_map(sbi, segno, off) == 0)
 451                         continue;
 452
 453                 if (phase == 0) {
 454                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 455                                                         META_NAT, true);
 456                         continue;
 457                 }
 458
 459                 if (phase == 1) {
 460                         ra_node_page(sbi, nid);
 461                         continue;
 462                 }
 463
 464                 /* phase == 2 */
 465                 node_page = get_node_page(sbi, nid);
 466                 if (IS_ERR(node_page))
 467                         continue;
 468
 469                 /* block may become invalid during get_node_page */
 470                 if (check_valid_map(sbi, segno, off) == 0) {
 471                         f2fs_put_page(node_page, 1);
 472                         continue;
 473                 }
 474
 475                 get_node_info(sbi, nid, &ni);
 476                 if (ni.blk_addr != start_addr + off) {
 477                         f2fs_put_page(node_page, 1);
 478                         continue;
 479                 }
 480
 481                 move_node_page(node_page, gc_type);
 482                 stat_inc_node_blk_count(sbi, 1, gc_type);
 483         }
 484
 485         if (++phase < 3)
 486                 goto next_step;
 487 }
 488
 489 /*
 490  * Calculate start block index indicating the given node offset.
 491  * Be careful, caller should give this node offset only indicating direct node
 492  * blocks. If any node offsets, which point the other types of node blocks such
 493  * as indirect or double indirect node blocks, are given, it must be a caller's
 494  * bug.
 495  */
 496 block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
 497 {
 498         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
 499         unsigned int bidx;
 500
 501         if (node_ofs == 0)
 502                 return 0;
 503
 504         if (node_ofs <= 2) {
 505                 bidx = node_ofs - 1;
 506         } else if (node_ofs <= indirect_blks) {
 507                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
 508                 bidx = node_ofs - 2 - dec;
 509         } else {
 510                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
 511                 bidx = node_ofs - 5 - dec;
 512         }
 513         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
 514 }
 515
 516 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 517                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
 518 {
 519         struct page *node_page;
 520         nid_t nid;
 521         unsigned int ofs_in_node;
 522         block_t source_blkaddr;
 523
 524         nid = le32_to_cpu(sum->nid);
 525         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
 526
 527         node_page = get_node_page(sbi, nid);
 528         if (IS_ERR(node_page))
 529                 return false;
 530
 531         get_node_info(sbi, nid, dni);
 532
 533         if (sum->version != dni->version) {
 534                 f2fs_put_page(node_page, 1);
 535                 return false;
 536         }
 537
 538         *nofs = ofs_of_node(node_page);
 539         source_blkaddr = datablock_addr(node_page, ofs_in_node);
 540         f2fs_put_page(node_page, 1);
 541
 542         if (source_blkaddr != blkaddr)
 543                 return false;
 544         return true;
 545 }
 546
 547 static void move_encrypted_block(struct inode *inode, block_t bidx)
 548 {
 549         struct f2fs_io_info fio = {
 550                 .sbi = F2FS_I_SB(inode),
 551                 .type = DATA,
 552                 .op = REQ_OP_READ,
 553                 .op_flags = READ_SYNC,
 554                 .encrypted_page = NULL,
 555         };
 556         struct dnode_of_data dn;
 557         struct f2fs_summary sum;
 558         struct node_info ni;
 559         struct page *page;
 560         block_t newaddr;
 561         int err;
 562
 563         /* do not read out */
 564         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
 565         if (!page)
 566                 return;
 567
 568         set_new_dnode(&dn, inode, NULL, NULL, 0);
 569         err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
 570         if (err)
 571                 goto out;
 572
 573         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
 574                 ClearPageUptodate(page);
 575                 goto put_out;
 576         }
 577
 578         /*
 579          * don't cache encrypted data into meta inode until previous dirty
 580          * data were writebacked to avoid racing between GC and flush.
 581          */
 582         f2fs_wait_on_page_writeback(page, DATA, true);
 583
 584         get_node_info(fio.sbi, dn.nid, &ni);
 585         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
 586
 587         /* read page */
 588         fio.page = page;
 589         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
 590
 591         allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
 592                                                         &sum, CURSEG_COLD_DATA);
 593
 594         fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
 595                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
 596         if (!fio.encrypted_page) {
 597                 err = -ENOMEM;
 598                 goto recover_block;
 599         }
 600
 601         err = f2fs_submit_page_bio(&fio);
 602         if (err)
 603                 goto put_page_out;
 604
 605         /* write page */
 606         lock_page(fio.encrypted_page);
 607
 608         if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
 609                 err = -EIO;
 610                 goto put_page_out;
 611         }
 612         if (unlikely(!PageUptodate(fio.encrypted_page))) {
 613                 err = -EIO;
 614                 goto put_page_out;
 615         }
 616
 617         set_page_dirty(fio.encrypted_page);
 618         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
 619         if (clear_page_dirty_for_io(fio.encrypted_page))
 620                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
 621
 622         set_page_writeback(fio.encrypted_page);
 623
 624         /* allocate block address */
 625         f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
 626
 627         fio.op = REQ_OP_WRITE;
 628         fio.op_flags = WRITE_SYNC;
 629         fio.new_blkaddr = newaddr;
 630         f2fs_submit_page_mbio(&fio);
 631
 632         f2fs_update_data_blkaddr(&dn, newaddr);
 633         set_inode_flag(inode, FI_APPEND_WRITE);
 634         if (page->index == 0)
 635                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
 636 put_page_out:
 637         f2fs_put_page(fio.encrypted_page, 1);
 638 recover_block:
 639         if (err)
 640                 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
 641                                                                 true, true);
 642 put_out:
 643         f2fs_put_dnode(&dn);
 644 out:
 645         f2fs_put_page(page, 1);
 646 }
 647
 648 static void move_data_page(struct inode *inode, block_t bidx, int gc_type)
 649 {
 650         struct page *page;
 651
 652         page = get_lock_data_page(inode, bidx, true);
 653         if (IS_ERR(page))
 654                 return;
 655
 656         if (gc_type == BG_GC) {
 657                 if (PageWriteback(page))
 658                         goto out;
 659                 set_page_dirty(page);
 660                 set_cold_data(page);
 661         } else {
 662                 struct f2fs_io_info fio = {
 663                         .sbi = F2FS_I_SB(inode),
 664                         .type = DATA,
 665                         .op = REQ_OP_WRITE,
 666                         .op_flags = WRITE_SYNC,
 667                         .page = page,
 668                         .encrypted_page = NULL,
 669                 };
 670                 bool is_dirty = PageDirty(page);
 671                 int err;
 672
 673 retry:
 674                 set_page_dirty(page);
 675                 f2fs_wait_on_page_writeback(page, DATA, true);
 676                 if (clear_page_dirty_for_io(page))
 677                         inode_dec_dirty_pages(inode);
 678
 679                 set_cold_data(page);
 680
 681                 err = do_write_data_page(&fio);
 682                 if (err == -ENOMEM && is_dirty) {
 683                         congestion_wait(BLK_RW_ASYNC, HZ/50);
 684                         goto retry;
 685                 }
 686
 687                 clear_cold_data(page);
 688         }
 689 out:
 690         f2fs_put_page(page, 1);
 691 }
 692
 693 /*
 694  * This function tries to get parent node of victim data block, and identifies
 695  * data block validity. If the block is valid, copy that with cold status and
 696  * modify parent node.
 697  * If the parent node is not valid or the data block address is different,
 698  * the victim data block is ignored.
 699  */
 700 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 701                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
 702 {
 703         struct super_block *sb = sbi->sb;
 704         struct f2fs_summary *entry;
 705         block_t start_addr;
 706         int off;
 707         int phase = 0;
 708
 709         start_addr = START_BLOCK(sbi, segno);
 710
 711 next_step:
 712         entry = sum;
 713
 714         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
 715                 struct page *data_page;
 716                 struct inode *inode;
 717                 struct node_info dni; /* dnode info for the data */
 718                 unsigned int ofs_in_node, nofs;
 719                 block_t start_bidx;
 720                 nid_t nid = le32_to_cpu(entry->nid);
 721
 722                 /* stop BG_GC if there is not enough free sections. */
 723                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
 724                         return;
 725
 726                 if (check_valid_map(sbi, segno, off) == 0)
 727                         continue;
 728
 729                 if (phase == 0) {
 730                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
 731                                                         META_NAT, true);
 732                         continue;
 733                 }
 734
 735                 if (phase == 1) {
 736                         ra_node_page(sbi, nid);
 737                         continue;
 738                 }
 739
 740                 /* Get an inode by ino with checking validity */
 741                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
 742                         continue;
 743
 744                 if (phase == 2) {
 745                         ra_node_page(sbi, dni.ino);
 746                         continue;
 747                 }
 748
 749                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
 750
 751                 if (phase == 3) {
 752                         inode = f2fs_iget(sb, dni.ino);
 753                         if (IS_ERR(inode) || is_bad_inode(inode))
 754                                 continue;
 755
 756                         /* if encrypted inode, let's go phase 3 */
 757                         if (f2fs_encrypted_inode(inode) &&
 758                                                 S_ISREG(inode->i_mode)) {
 759                                 add_gc_inode(gc_list, inode);
 760                                 continue;
 761                         }
 762
 763                         start_bidx = start_bidx_of_node(nofs, inode);
 764                         data_page = get_read_data_page(inode,
 765                                         start_bidx + ofs_in_node, REQ_RAHEAD,
 766                                         true);
 767                         if (IS_ERR(data_page)) {
 768                                 iput(inode);
 769                                 continue;
 770                         }
 771
 772                         f2fs_put_page(data_page, 0);
 773                         add_gc_inode(gc_list, inode);
 774                         continue;
 775                 }
 776
 777                 /* phase 4 */
 778                 inode = find_gc_inode(gc_list, dni.ino);
 779                 if (inode) {
 780                         struct f2fs_inode_info *fi = F2FS_I(inode);
 781                         bool locked = false;
 782
 783                         if (S_ISREG(inode->i_mode)) {
 784                                 if (!down_write_trylock(&fi->dio_rwsem[READ]))
 785                                         continue;
 786                                 if (!down_write_trylock(
 787                                                 &fi->dio_rwsem[WRITE])) {
 788                                         up_write(&fi->dio_rwsem[READ]);
 789                                         continue;
 790                                 }
 791                                 locked = true;
 792                         }
 793
 794                         start_bidx = start_bidx_of_node(nofs, inode)
 795                                                                 + ofs_in_node;
 796                         if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
 797                                 move_encrypted_block(inode, start_bidx);
 798                         else
 799                                 move_data_page(inode, start_bidx, gc_type);
 800
 801                         if (locked) {
 802                                 up_write(&fi->dio_rwsem[WRITE]);
 803                                 up_write(&fi->dio_rwsem[READ]);
 804                         }
 805
 806                         stat_inc_data_blk_count(sbi, 1, gc_type);
 807                 }
 808         }
 809
 810         if (++phase < 5)
 811                 goto next_step;
 812 }
 813
 814 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
 815                         int gc_type)
 816 {
 817         struct sit_info *sit_i = SIT_I(sbi);
 818         int ret;
 819
 820         mutex_lock(&sit_i->sentry_lock);
 821         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
 822                                               NO_CHECK_TYPE, LFS);
 823         mutex_unlock(&sit_i->sentry_lock);
 824         return ret;
 825 }
 826
 827 static int do_garbage_collect(struct f2fs_sb_info *sbi,
 828                                 unsigned int start_segno,
 829                                 struct gc_inode_list *gc_list, int gc_type)
 830 {
 831         struct page *sum_page;
 832         struct f2fs_summary_block *sum;
 833         struct blk_plug plug;
 834         unsigned int segno = start_segno;
 835         unsigned int end_segno = start_segno + sbi->segs_per_sec;
 836         int sec_freed = 0;
 837         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
 838                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
 839
 840         /* readahead multi ssa blocks those have contiguous address */
 841         if (sbi->segs_per_sec > 1)
 842                 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
 843                                         sbi->segs_per_sec, META_SSA, true);
 844
 845         /* reference all summary page */
 846         while (segno < end_segno) {
 847                 sum_page = get_sum_page(sbi, segno++);
 848                 unlock_page(sum_page);
 849         }
 850
 851         blk_start_plug(&plug);
 852
 853         for (segno = start_segno; segno < end_segno; segno++) {
 854
 855                 if (get_valid_blocks(sbi, segno, 1) == 0 ||
 856                                         unlikely(f2fs_cp_error(sbi)))
 857                         goto next;
 858
 859                 /* find segment summary of victim */
 860                 sum_page = find_get_page(META_MAPPING(sbi),
 861                                         GET_SUM_BLOCK(sbi, segno));
 862                 f2fs_bug_on(sbi, !PageUptodate(sum_page));
 863                 f2fs_put_page(sum_page, 0);
 864
 865                 sum = page_address(sum_page);
 866                 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
 867
 868                 /*
 869                  * this is to avoid deadlock:
 870                  * - lock_page(sum_page)         - f2fs_replace_block
 871                  *  - check_valid_map()            - mutex_lock(sentry_lock)
 872                  *   - mutex_lock(sentry_lock)     - change_curseg()
 873                  *                                  - lock_page(sum_page)
 874                  */
 875
 876                 if (type == SUM_TYPE_NODE)
 877                         gc_node_segment(sbi, sum->entries, segno, gc_type);
 878                 else
 879                         gc_data_segment(sbi, sum->entries, gc_list, segno,
 880                                                                 gc_type);
 881
 882                 stat_inc_seg_count(sbi, type, gc_type);
 883 next:
 884                 f2fs_put_page(sum_page, 0);
 885         }
 886
 887         if (gc_type == FG_GC)
 888                 f2fs_submit_merged_bio(sbi,
 889                                 (type == SUM_TYPE_NODE) ? NODE : DATA, WRITE);
 890
 891         blk_finish_plug(&plug);
 892
 893         if (gc_type == FG_GC &&
 894                 get_valid_blocks(sbi, start_segno, sbi->segs_per_sec) == 0)
 895                 sec_freed = 1;
 896
 897         stat_inc_call_count(sbi->stat_info);
 898
 899         return sec_freed;
 900 }
 901
 902 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync)
 903 {
 904         unsigned int segno;
 905         int gc_type = sync ? FG_GC : BG_GC;
 906         int sec_freed = 0;
 907         int ret = -EINVAL;
 908         struct cp_control cpc;
 909         struct gc_inode_list gc_list = {
 910                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
 911                 .iroot = RADIX_TREE_INIT(GFP_NOFS),
 912         };
 913
 914         cpc.reason = __get_cp_reason(sbi);
 915 gc_more:
 916         segno = NULL_SEGNO;
 917
 918         if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
 919                 goto stop;
 920         if (unlikely(f2fs_cp_error(sbi))) {
 921                 ret = -EIO;
 922                 goto stop;
 923         }
 924
 925         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed, 0)) {
 926                 gc_type = FG_GC;
 927                 /*
 928                  * If there is no victim and no prefree segment but still not
 929                  * enough free sections, we should flush dent/node blocks and do
 930                  * garbage collections.
 931                  */
 932                 if (__get_victim(sbi, &segno, gc_type) ||
 933                                                 prefree_segments(sbi)) {
 934                         ret = write_checkpoint(sbi, &cpc);
 935                         if (ret)
 936                                 goto stop;
 937                         segno = NULL_SEGNO;
 938                 } else if (has_not_enough_free_secs(sbi, 0, 0)) {
 939                         ret = write_checkpoint(sbi, &cpc);
 940                         if (ret)
 941                                 goto stop;
 942                 }
 943         }
 944
 945         if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type))
 946                 goto stop;
 947         ret = 0;
 948
 949         if (do_garbage_collect(sbi, segno, &gc_list, gc_type) &&
 950                         gc_type == FG_GC)
 951                 sec_freed++;
 952
 953         if (gc_type == FG_GC)
 954                 sbi->cur_victim_sec = NULL_SEGNO;
 955
 956         if (!sync) {
 957                 if (has_not_enough_free_secs(sbi, sec_freed, 0))
 958                         goto gc_more;
 959
 960                 if (gc_type == FG_GC)
 961                         ret = write_checkpoint(sbi, &cpc);
 962         }
 963 stop:
 964         mutex_unlock(&sbi->gc_mutex);
 965
 966         put_gc_inode(&gc_list);
 967
 968         if (sync)
 969                 ret = sec_freed ? 0 : -EAGAIN;
 970         return ret;
 971 }
 972
 973 void build_gc_manager(struct f2fs_sb_info *sbi)
 974 {
 975         DIRTY_I(sbi)->v_ops = &default_v_ops;
 976 }