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