Loading...
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
26static 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
93int 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 = 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 }
120out:
121 return err;
122}
123
124void 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
134static 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
147static 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
170static 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
184static 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
203static 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
235static 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
248static 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 */
268static 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 }
334next:
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) {
344got_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 }
358out:
359 mutex_unlock(&dirty_i->seglist_lock);
360
361 return (p.min_segno == NULL_SEGNO) ? 0 : 1;
362}
363
364static const struct victim_selection default_v_ops = {
365 .get_victim = get_victim_by_default,
366};
367
368static 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
378static 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
393static 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
404static 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 */
423static 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
433next_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 /* set page dirty and write it */
469 if (gc_type == FG_GC) {
470 f2fs_wait_on_page_writeback(node_page, NODE, true);
471 set_page_dirty(node_page);
472 } else {
473 if (!PageWriteback(node_page))
474 set_page_dirty(node_page);
475 }
476 f2fs_put_page(node_page, 1);
477 stat_inc_node_blk_count(sbi, 1, gc_type);
478 }
479
480 if (initial) {
481 initial = false;
482 goto next_step;
483 }
484}
485
486/*
487 * Calculate start block index indicating the given node offset.
488 * Be careful, caller should give this node offset only indicating direct node
489 * blocks. If any node offsets, which point the other types of node blocks such
490 * as indirect or double indirect node blocks, are given, it must be a caller's
491 * bug.
492 */
493block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
494{
495 unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
496 unsigned int bidx;
497
498 if (node_ofs == 0)
499 return 0;
500
501 if (node_ofs <= 2) {
502 bidx = node_ofs - 1;
503 } else if (node_ofs <= indirect_blks) {
504 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
505 bidx = node_ofs - 2 - dec;
506 } else {
507 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
508 bidx = node_ofs - 5 - dec;
509 }
510 return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
511}
512
513static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
514 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
515{
516 struct page *node_page;
517 nid_t nid;
518 unsigned int ofs_in_node;
519 block_t source_blkaddr;
520
521 nid = le32_to_cpu(sum->nid);
522 ofs_in_node = le16_to_cpu(sum->ofs_in_node);
523
524 node_page = get_node_page(sbi, nid);
525 if (IS_ERR(node_page))
526 return false;
527
528 get_node_info(sbi, nid, dni);
529
530 if (sum->version != dni->version) {
531 f2fs_put_page(node_page, 1);
532 return false;
533 }
534
535 *nofs = ofs_of_node(node_page);
536 source_blkaddr = datablock_addr(node_page, ofs_in_node);
537 f2fs_put_page(node_page, 1);
538
539 if (source_blkaddr != blkaddr)
540 return false;
541 return true;
542}
543
544static void move_encrypted_block(struct inode *inode, block_t bidx)
545{
546 struct f2fs_io_info fio = {
547 .sbi = F2FS_I_SB(inode),
548 .type = DATA,
549 .rw = READ_SYNC,
550 .encrypted_page = NULL,
551 };
552 struct dnode_of_data dn;
553 struct f2fs_summary sum;
554 struct node_info ni;
555 struct page *page;
556 block_t newaddr;
557 int err;
558
559 /* do not read out */
560 page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
561 if (!page)
562 return;
563
564 set_new_dnode(&dn, inode, NULL, NULL, 0);
565 err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
566 if (err)
567 goto out;
568
569 if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
570 ClearPageUptodate(page);
571 goto put_out;
572 }
573
574 /*
575 * don't cache encrypted data into meta inode until previous dirty
576 * data were writebacked to avoid racing between GC and flush.
577 */
578 f2fs_wait_on_page_writeback(page, DATA, true);
579
580 get_node_info(fio.sbi, dn.nid, &ni);
581 set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
582
583 /* read page */
584 fio.page = page;
585 fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
586
587 allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
588 &sum, CURSEG_COLD_DATA);
589
590 fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
591 FGP_LOCK | FGP_CREAT, GFP_NOFS);
592 if (!fio.encrypted_page) {
593 err = -ENOMEM;
594 goto recover_block;
595 }
596
597 err = f2fs_submit_page_bio(&fio);
598 if (err)
599 goto put_page_out;
600
601 /* write page */
602 lock_page(fio.encrypted_page);
603
604 if (unlikely(!PageUptodate(fio.encrypted_page))) {
605 err = -EIO;
606 goto put_page_out;
607 }
608 if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
609 err = -EIO;
610 goto put_page_out;
611 }
612
613 set_page_dirty(fio.encrypted_page);
614 f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
615 if (clear_page_dirty_for_io(fio.encrypted_page))
616 dec_page_count(fio.sbi, F2FS_DIRTY_META);
617
618 set_page_writeback(fio.encrypted_page);
619
620 /* allocate block address */
621 f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
622
623 fio.rw = WRITE_SYNC;
624 fio.new_blkaddr = newaddr;
625 f2fs_submit_page_mbio(&fio);
626
627 f2fs_update_data_blkaddr(&dn, newaddr);
628 set_inode_flag(F2FS_I(inode), FI_APPEND_WRITE);
629 if (page->index == 0)
630 set_inode_flag(F2FS_I(inode), FI_FIRST_BLOCK_WRITTEN);
631put_page_out:
632 f2fs_put_page(fio.encrypted_page, 1);
633recover_block:
634 if (err)
635 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
636 true, true);
637put_out:
638 f2fs_put_dnode(&dn);
639out:
640 f2fs_put_page(page, 1);
641}
642
643static void move_data_page(struct inode *inode, block_t bidx, int gc_type)
644{
645 struct page *page;
646
647 page = get_lock_data_page(inode, bidx, true);
648 if (IS_ERR(page))
649 return;
650
651 if (gc_type == BG_GC) {
652 if (PageWriteback(page))
653 goto out;
654 set_page_dirty(page);
655 set_cold_data(page);
656 } else {
657 struct f2fs_io_info fio = {
658 .sbi = F2FS_I_SB(inode),
659 .type = DATA,
660 .rw = WRITE_SYNC,
661 .page = page,
662 .encrypted_page = NULL,
663 };
664 set_page_dirty(page);
665 f2fs_wait_on_page_writeback(page, DATA, true);
666 if (clear_page_dirty_for_io(page))
667 inode_dec_dirty_pages(inode);
668 set_cold_data(page);
669 do_write_data_page(&fio);
670 clear_cold_data(page);
671 }
672out:
673 f2fs_put_page(page, 1);
674}
675
676/*
677 * This function tries to get parent node of victim data block, and identifies
678 * data block validity. If the block is valid, copy that with cold status and
679 * modify parent node.
680 * If the parent node is not valid or the data block address is different,
681 * the victim data block is ignored.
682 */
683static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
684 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
685{
686 struct super_block *sb = sbi->sb;
687 struct f2fs_summary *entry;
688 block_t start_addr;
689 int off;
690 int phase = 0;
691
692 start_addr = START_BLOCK(sbi, segno);
693
694next_step:
695 entry = sum;
696
697 for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
698 struct page *data_page;
699 struct inode *inode;
700 struct node_info dni; /* dnode info for the data */
701 unsigned int ofs_in_node, nofs;
702 block_t start_bidx;
703
704 /* stop BG_GC if there is not enough free sections. */
705 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
706 return;
707
708 if (check_valid_map(sbi, segno, off) == 0)
709 continue;
710
711 if (phase == 0) {
712 ra_node_page(sbi, le32_to_cpu(entry->nid));
713 continue;
714 }
715
716 /* Get an inode by ino with checking validity */
717 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
718 continue;
719
720 if (phase == 1) {
721 ra_node_page(sbi, dni.ino);
722 continue;
723 }
724
725 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
726
727 if (phase == 2) {
728 inode = f2fs_iget(sb, dni.ino);
729 if (IS_ERR(inode) || is_bad_inode(inode))
730 continue;
731
732 /* if encrypted inode, let's go phase 3 */
733 if (f2fs_encrypted_inode(inode) &&
734 S_ISREG(inode->i_mode)) {
735 add_gc_inode(gc_list, inode);
736 continue;
737 }
738
739 start_bidx = start_bidx_of_node(nofs, inode);
740 data_page = get_read_data_page(inode,
741 start_bidx + ofs_in_node, READA, true);
742 if (IS_ERR(data_page)) {
743 iput(inode);
744 continue;
745 }
746
747 f2fs_put_page(data_page, 0);
748 add_gc_inode(gc_list, inode);
749 continue;
750 }
751
752 /* phase 3 */
753 inode = find_gc_inode(gc_list, dni.ino);
754 if (inode) {
755 start_bidx = start_bidx_of_node(nofs, inode)
756 + ofs_in_node;
757 if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
758 move_encrypted_block(inode, start_bidx);
759 else
760 move_data_page(inode, start_bidx, gc_type);
761 stat_inc_data_blk_count(sbi, 1, gc_type);
762 }
763 }
764
765 if (++phase < 4)
766 goto next_step;
767}
768
769static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
770 int gc_type)
771{
772 struct sit_info *sit_i = SIT_I(sbi);
773 int ret;
774
775 mutex_lock(&sit_i->sentry_lock);
776 ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
777 NO_CHECK_TYPE, LFS);
778 mutex_unlock(&sit_i->sentry_lock);
779 return ret;
780}
781
782static int do_garbage_collect(struct f2fs_sb_info *sbi,
783 unsigned int start_segno,
784 struct gc_inode_list *gc_list, int gc_type)
785{
786 struct page *sum_page;
787 struct f2fs_summary_block *sum;
788 struct blk_plug plug;
789 unsigned int segno = start_segno;
790 unsigned int end_segno = start_segno + sbi->segs_per_sec;
791 int seg_freed = 0;
792 unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
793 SUM_TYPE_DATA : SUM_TYPE_NODE;
794
795 /* readahead multi ssa blocks those have contiguous address */
796 if (sbi->segs_per_sec > 1)
797 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
798 sbi->segs_per_sec, META_SSA, true);
799
800 /* reference all summary page */
801 while (segno < end_segno) {
802 sum_page = get_sum_page(sbi, segno++);
803 unlock_page(sum_page);
804 }
805
806 blk_start_plug(&plug);
807
808 for (segno = start_segno; segno < end_segno; segno++) {
809 /* find segment summary of victim */
810 sum_page = find_get_page(META_MAPPING(sbi),
811 GET_SUM_BLOCK(sbi, segno));
812 f2fs_bug_on(sbi, !PageUptodate(sum_page));
813 f2fs_put_page(sum_page, 0);
814
815 sum = page_address(sum_page);
816 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
817
818 /*
819 * this is to avoid deadlock:
820 * - lock_page(sum_page) - f2fs_replace_block
821 * - check_valid_map() - mutex_lock(sentry_lock)
822 * - mutex_lock(sentry_lock) - change_curseg()
823 * - lock_page(sum_page)
824 */
825
826 if (type == SUM_TYPE_NODE)
827 gc_node_segment(sbi, sum->entries, segno, gc_type);
828 else
829 gc_data_segment(sbi, sum->entries, gc_list, segno,
830 gc_type);
831
832 stat_inc_seg_count(sbi, type, gc_type);
833
834 f2fs_put_page(sum_page, 0);
835 }
836
837 if (gc_type == FG_GC) {
838 if (type == SUM_TYPE_NODE) {
839 struct writeback_control wbc = {
840 .sync_mode = WB_SYNC_ALL,
841 .nr_to_write = LONG_MAX,
842 .for_reclaim = 0,
843 };
844 sync_node_pages(sbi, 0, &wbc);
845 } else {
846 f2fs_submit_merged_bio(sbi, DATA, WRITE);
847 }
848 }
849
850 blk_finish_plug(&plug);
851
852 if (gc_type == FG_GC) {
853 while (start_segno < end_segno)
854 if (get_valid_blocks(sbi, start_segno++, 1) == 0)
855 seg_freed++;
856 }
857
858 stat_inc_call_count(sbi->stat_info);
859
860 return seg_freed;
861}
862
863int f2fs_gc(struct f2fs_sb_info *sbi, bool sync)
864{
865 unsigned int segno;
866 int gc_type = sync ? FG_GC : BG_GC;
867 int sec_freed = 0, seg_freed;
868 int ret = -EINVAL;
869 struct cp_control cpc;
870 struct gc_inode_list gc_list = {
871 .ilist = LIST_HEAD_INIT(gc_list.ilist),
872 .iroot = RADIX_TREE_INIT(GFP_NOFS),
873 };
874
875 cpc.reason = __get_cp_reason(sbi);
876gc_more:
877 segno = NULL_SEGNO;
878
879 if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
880 goto stop;
881 if (unlikely(f2fs_cp_error(sbi))) {
882 ret = -EIO;
883 goto stop;
884 }
885
886 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed)) {
887 gc_type = FG_GC;
888 /*
889 * If there is no victim and no prefree segment but still not
890 * enough free sections, we should flush dent/node blocks and do
891 * garbage collections.
892 */
893 if (__get_victim(sbi, &segno, gc_type) || prefree_segments(sbi))
894 write_checkpoint(sbi, &cpc);
895 else if (has_not_enough_free_secs(sbi, 0))
896 write_checkpoint(sbi, &cpc);
897 }
898
899 if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type))
900 goto stop;
901 ret = 0;
902
903 seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
904
905 if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
906 sec_freed++;
907
908 if (gc_type == FG_GC)
909 sbi->cur_victim_sec = NULL_SEGNO;
910
911 if (!sync) {
912 if (has_not_enough_free_secs(sbi, sec_freed))
913 goto gc_more;
914
915 if (gc_type == FG_GC)
916 write_checkpoint(sbi, &cpc);
917 }
918stop:
919 mutex_unlock(&sbi->gc_mutex);
920
921 put_gc_inode(&gc_list);
922
923 if (sync)
924 ret = sec_freed ? 0 : -EAGAIN;
925 return ret;
926}
927
928void build_gc_manager(struct f2fs_sb_info *sbi)
929{
930 DIRTY_I(sbi)->v_ops = &default_v_ops;
931}
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#include <linux/blkdev.h>
20
21#include "f2fs.h"
22#include "node.h"
23#include "segment.h"
24#include "gc.h"
25#include <trace/events/f2fs.h>
26
27static struct kmem_cache *winode_slab;
28
29static int gc_thread_func(void *data)
30{
31 struct f2fs_sb_info *sbi = data;
32 struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
33 wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
34 long wait_ms;
35
36 wait_ms = gc_th->min_sleep_time;
37
38 do {
39 if (try_to_freeze())
40 continue;
41 else
42 wait_event_interruptible_timeout(*wq,
43 kthread_should_stop(),
44 msecs_to_jiffies(wait_ms));
45 if (kthread_should_stop())
46 break;
47
48 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
49 wait_ms = increase_sleep_time(gc_th, wait_ms);
50 continue;
51 }
52
53 /*
54 * [GC triggering condition]
55 * 0. GC is not conducted currently.
56 * 1. There are enough dirty segments.
57 * 2. IO subsystem is idle by checking the # of writeback pages.
58 * 3. IO subsystem is idle by checking the # of requests in
59 * bdev's request list.
60 *
61 * Note) We have to avoid triggering GCs too much frequently.
62 * Because it is possible that some segments can be
63 * invalidated soon after by user update or deletion.
64 * So, I'd like to wait some time to collect dirty segments.
65 */
66 if (!mutex_trylock(&sbi->gc_mutex))
67 continue;
68
69 if (!is_idle(sbi)) {
70 wait_ms = increase_sleep_time(gc_th, wait_ms);
71 mutex_unlock(&sbi->gc_mutex);
72 continue;
73 }
74
75 if (has_enough_invalid_blocks(sbi))
76 wait_ms = decrease_sleep_time(gc_th, wait_ms);
77 else
78 wait_ms = increase_sleep_time(gc_th, wait_ms);
79
80 stat_inc_bggc_count(sbi);
81
82 /* if return value is not zero, no victim was selected */
83 if (f2fs_gc(sbi))
84 wait_ms = gc_th->no_gc_sleep_time;
85
86 /* balancing f2fs's metadata periodically */
87 f2fs_balance_fs_bg(sbi);
88
89 } while (!kthread_should_stop());
90 return 0;
91}
92
93int 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 if (!test_opt(sbi, BG_GC))
100 goto out;
101 gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
102 if (!gc_th) {
103 err = -ENOMEM;
104 goto out;
105 }
106
107 gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
108 gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
109 gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
110
111 gc_th->gc_idle = 0;
112
113 sbi->gc_thread = gc_th;
114 init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
115 sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
116 "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
117 if (IS_ERR(gc_th->f2fs_gc_task)) {
118 err = PTR_ERR(gc_th->f2fs_gc_task);
119 kfree(gc_th);
120 sbi->gc_thread = NULL;
121 }
122out:
123 return err;
124}
125
126void stop_gc_thread(struct f2fs_sb_info *sbi)
127{
128 struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
129 if (!gc_th)
130 return;
131 kthread_stop(gc_th->f2fs_gc_task);
132 kfree(gc_th);
133 sbi->gc_thread = NULL;
134}
135
136static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
137{
138 int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
139
140 if (gc_th && gc_th->gc_idle) {
141 if (gc_th->gc_idle == 1)
142 gc_mode = GC_CB;
143 else if (gc_th->gc_idle == 2)
144 gc_mode = GC_GREEDY;
145 }
146 return gc_mode;
147}
148
149static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
150 int type, struct victim_sel_policy *p)
151{
152 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
153
154 if (p->alloc_mode == SSR) {
155 p->gc_mode = GC_GREEDY;
156 p->dirty_segmap = dirty_i->dirty_segmap[type];
157 p->max_search = dirty_i->nr_dirty[type];
158 p->ofs_unit = 1;
159 } else {
160 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
161 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
162 p->max_search = dirty_i->nr_dirty[DIRTY];
163 p->ofs_unit = sbi->segs_per_sec;
164 }
165
166 if (p->max_search > sbi->max_victim_search)
167 p->max_search = sbi->max_victim_search;
168
169 p->offset = sbi->last_victim[p->gc_mode];
170}
171
172static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
173 struct victim_sel_policy *p)
174{
175 /* SSR allocates in a segment unit */
176 if (p->alloc_mode == SSR)
177 return 1 << sbi->log_blocks_per_seg;
178 if (p->gc_mode == GC_GREEDY)
179 return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
180 else if (p->gc_mode == GC_CB)
181 return UINT_MAX;
182 else /* No other gc_mode */
183 return 0;
184}
185
186static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
187{
188 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
189 unsigned int hint = 0;
190 unsigned int secno;
191
192 /*
193 * If the gc_type is FG_GC, we can select victim segments
194 * selected by background GC before.
195 * Those segments guarantee they have small valid blocks.
196 */
197next:
198 secno = find_next_bit(dirty_i->victim_secmap, TOTAL_SECS(sbi), hint++);
199 if (secno < TOTAL_SECS(sbi)) {
200 if (sec_usage_check(sbi, secno))
201 goto next;
202 clear_bit(secno, dirty_i->victim_secmap);
203 return secno * sbi->segs_per_sec;
204 }
205 return NULL_SEGNO;
206}
207
208static 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 is changed by 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
240static 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/*
254 * This function is called from two paths.
255 * One is garbage collection and the other is SSR segment selection.
256 * When it is called during GC, it just gets a victim segment
257 * and it does not remove it from dirty seglist.
258 * When it is called from SSR segment selection, it finds a segment
259 * which has minimum valid blocks and removes it from dirty seglist.
260 */
261static int get_victim_by_default(struct f2fs_sb_info *sbi,
262 unsigned int *result, int gc_type, int type, char alloc_mode)
263{
264 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
265 struct victim_sel_policy p;
266 unsigned int secno, max_cost;
267 int nsearched = 0;
268
269 p.alloc_mode = alloc_mode;
270 select_policy(sbi, gc_type, type, &p);
271
272 p.min_segno = NULL_SEGNO;
273 p.min_cost = max_cost = get_max_cost(sbi, &p);
274
275 mutex_lock(&dirty_i->seglist_lock);
276
277 if (p.alloc_mode == LFS && gc_type == FG_GC) {
278 p.min_segno = check_bg_victims(sbi);
279 if (p.min_segno != NULL_SEGNO)
280 goto got_it;
281 }
282
283 while (1) {
284 unsigned long cost;
285 unsigned int segno;
286
287 segno = find_next_bit(p.dirty_segmap,
288 TOTAL_SEGS(sbi), p.offset);
289 if (segno >= TOTAL_SEGS(sbi)) {
290 if (sbi->last_victim[p.gc_mode]) {
291 sbi->last_victim[p.gc_mode] = 0;
292 p.offset = 0;
293 continue;
294 }
295 break;
296 }
297
298 p.offset = segno + p.ofs_unit;
299 if (p.ofs_unit > 1)
300 p.offset -= segno % p.ofs_unit;
301
302 secno = GET_SECNO(sbi, segno);
303
304 if (sec_usage_check(sbi, secno))
305 continue;
306 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
307 continue;
308
309 cost = get_gc_cost(sbi, segno, &p);
310
311 if (p.min_cost > cost) {
312 p.min_segno = segno;
313 p.min_cost = cost;
314 } else if (unlikely(cost == max_cost)) {
315 continue;
316 }
317
318 if (nsearched++ >= p.max_search) {
319 sbi->last_victim[p.gc_mode] = segno;
320 break;
321 }
322 }
323 if (p.min_segno != NULL_SEGNO) {
324got_it:
325 if (p.alloc_mode == LFS) {
326 secno = GET_SECNO(sbi, p.min_segno);
327 if (gc_type == FG_GC)
328 sbi->cur_victim_sec = secno;
329 else
330 set_bit(secno, dirty_i->victim_secmap);
331 }
332 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
333
334 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
335 sbi->cur_victim_sec,
336 prefree_segments(sbi), free_segments(sbi));
337 }
338 mutex_unlock(&dirty_i->seglist_lock);
339
340 return (p.min_segno == NULL_SEGNO) ? 0 : 1;
341}
342
343static const struct victim_selection default_v_ops = {
344 .get_victim = get_victim_by_default,
345};
346
347static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
348{
349 struct inode_entry *ie;
350
351 list_for_each_entry(ie, ilist, list)
352 if (ie->inode->i_ino == ino)
353 return ie->inode;
354 return NULL;
355}
356
357static void add_gc_inode(struct inode *inode, struct list_head *ilist)
358{
359 struct inode_entry *new_ie;
360
361 if (inode == find_gc_inode(inode->i_ino, ilist)) {
362 iput(inode);
363 return;
364 }
365
366 new_ie = f2fs_kmem_cache_alloc(winode_slab, GFP_NOFS);
367 new_ie->inode = inode;
368 list_add_tail(&new_ie->list, ilist);
369}
370
371static void put_gc_inode(struct list_head *ilist)
372{
373 struct inode_entry *ie, *next_ie;
374 list_for_each_entry_safe(ie, next_ie, ilist, list) {
375 iput(ie->inode);
376 list_del(&ie->list);
377 kmem_cache_free(winode_slab, ie);
378 }
379}
380
381static int check_valid_map(struct f2fs_sb_info *sbi,
382 unsigned int segno, int offset)
383{
384 struct sit_info *sit_i = SIT_I(sbi);
385 struct seg_entry *sentry;
386 int ret;
387
388 mutex_lock(&sit_i->sentry_lock);
389 sentry = get_seg_entry(sbi, segno);
390 ret = f2fs_test_bit(offset, sentry->cur_valid_map);
391 mutex_unlock(&sit_i->sentry_lock);
392 return ret;
393}
394
395/*
396 * This function compares node address got in summary with that in NAT.
397 * On validity, copy that node with cold status, otherwise (invalid node)
398 * ignore that.
399 */
400static void gc_node_segment(struct f2fs_sb_info *sbi,
401 struct f2fs_summary *sum, unsigned int segno, int gc_type)
402{
403 bool initial = true;
404 struct f2fs_summary *entry;
405 int off;
406
407next_step:
408 entry = sum;
409
410 for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
411 nid_t nid = le32_to_cpu(entry->nid);
412 struct page *node_page;
413
414 /* stop BG_GC if there is not enough free sections. */
415 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
416 return;
417
418 if (check_valid_map(sbi, segno, off) == 0)
419 continue;
420
421 if (initial) {
422 ra_node_page(sbi, nid);
423 continue;
424 }
425 node_page = get_node_page(sbi, nid);
426 if (IS_ERR(node_page))
427 continue;
428
429 /* set page dirty and write it */
430 if (gc_type == FG_GC) {
431 f2fs_wait_on_page_writeback(node_page, NODE);
432 set_page_dirty(node_page);
433 } else {
434 if (!PageWriteback(node_page))
435 set_page_dirty(node_page);
436 }
437 f2fs_put_page(node_page, 1);
438 stat_inc_node_blk_count(sbi, 1);
439 }
440
441 if (initial) {
442 initial = false;
443 goto next_step;
444 }
445
446 if (gc_type == FG_GC) {
447 struct writeback_control wbc = {
448 .sync_mode = WB_SYNC_ALL,
449 .nr_to_write = LONG_MAX,
450 .for_reclaim = 0,
451 };
452 sync_node_pages(sbi, 0, &wbc);
453
454 /*
455 * In the case of FG_GC, it'd be better to reclaim this victim
456 * completely.
457 */
458 if (get_valid_blocks(sbi, segno, 1) != 0)
459 goto next_step;
460 }
461}
462
463/*
464 * Calculate start block index indicating the given node offset.
465 * Be careful, caller should give this node offset only indicating direct node
466 * blocks. If any node offsets, which point the other types of node blocks such
467 * as indirect or double indirect node blocks, are given, it must be a caller's
468 * bug.
469 */
470block_t start_bidx_of_node(unsigned int node_ofs, struct f2fs_inode_info *fi)
471{
472 unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
473 unsigned int bidx;
474
475 if (node_ofs == 0)
476 return 0;
477
478 if (node_ofs <= 2) {
479 bidx = node_ofs - 1;
480 } else if (node_ofs <= indirect_blks) {
481 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
482 bidx = node_ofs - 2 - dec;
483 } else {
484 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
485 bidx = node_ofs - 5 - dec;
486 }
487 return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi);
488}
489
490static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
491 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
492{
493 struct page *node_page;
494 nid_t nid;
495 unsigned int ofs_in_node;
496 block_t source_blkaddr;
497
498 nid = le32_to_cpu(sum->nid);
499 ofs_in_node = le16_to_cpu(sum->ofs_in_node);
500
501 node_page = get_node_page(sbi, nid);
502 if (IS_ERR(node_page))
503 return 0;
504
505 get_node_info(sbi, nid, dni);
506
507 if (sum->version != dni->version) {
508 f2fs_put_page(node_page, 1);
509 return 0;
510 }
511
512 *nofs = ofs_of_node(node_page);
513 source_blkaddr = datablock_addr(node_page, ofs_in_node);
514 f2fs_put_page(node_page, 1);
515
516 if (source_blkaddr != blkaddr)
517 return 0;
518 return 1;
519}
520
521static void move_data_page(struct inode *inode, struct page *page, int gc_type)
522{
523 struct f2fs_io_info fio = {
524 .type = DATA,
525 .rw = WRITE_SYNC,
526 };
527
528 if (gc_type == BG_GC) {
529 if (PageWriteback(page))
530 goto out;
531 set_page_dirty(page);
532 set_cold_data(page);
533 } else {
534 f2fs_wait_on_page_writeback(page, DATA);
535
536 if (clear_page_dirty_for_io(page))
537 inode_dec_dirty_dents(inode);
538 set_cold_data(page);
539 do_write_data_page(page, &fio);
540 clear_cold_data(page);
541 }
542out:
543 f2fs_put_page(page, 1);
544}
545
546/*
547 * This function tries to get parent node of victim data block, and identifies
548 * data block validity. If the block is valid, copy that with cold status and
549 * modify parent node.
550 * If the parent node is not valid or the data block address is different,
551 * the victim data block is ignored.
552 */
553static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
554 struct list_head *ilist, unsigned int segno, int gc_type)
555{
556 struct super_block *sb = sbi->sb;
557 struct f2fs_summary *entry;
558 block_t start_addr;
559 int off;
560 int phase = 0;
561
562 start_addr = START_BLOCK(sbi, segno);
563
564next_step:
565 entry = sum;
566
567 for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
568 struct page *data_page;
569 struct inode *inode;
570 struct node_info dni; /* dnode info for the data */
571 unsigned int ofs_in_node, nofs;
572 block_t start_bidx;
573
574 /* stop BG_GC if there is not enough free sections. */
575 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
576 return;
577
578 if (check_valid_map(sbi, segno, off) == 0)
579 continue;
580
581 if (phase == 0) {
582 ra_node_page(sbi, le32_to_cpu(entry->nid));
583 continue;
584 }
585
586 /* Get an inode by ino with checking validity */
587 if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
588 continue;
589
590 if (phase == 1) {
591 ra_node_page(sbi, dni.ino);
592 continue;
593 }
594
595 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
596
597 if (phase == 2) {
598 inode = f2fs_iget(sb, dni.ino);
599 if (IS_ERR(inode))
600 continue;
601
602 start_bidx = start_bidx_of_node(nofs, F2FS_I(inode));
603
604 data_page = find_data_page(inode,
605 start_bidx + ofs_in_node, false);
606 if (IS_ERR(data_page))
607 goto next_iput;
608
609 f2fs_put_page(data_page, 0);
610 add_gc_inode(inode, ilist);
611 } else {
612 inode = find_gc_inode(dni.ino, ilist);
613 if (inode) {
614 start_bidx = start_bidx_of_node(nofs,
615 F2FS_I(inode));
616 data_page = get_lock_data_page(inode,
617 start_bidx + ofs_in_node);
618 if (IS_ERR(data_page))
619 continue;
620 move_data_page(inode, data_page, gc_type);
621 stat_inc_data_blk_count(sbi, 1);
622 }
623 }
624 continue;
625next_iput:
626 iput(inode);
627 }
628
629 if (++phase < 4)
630 goto next_step;
631
632 if (gc_type == FG_GC) {
633 f2fs_submit_merged_bio(sbi, DATA, WRITE);
634
635 /*
636 * In the case of FG_GC, it'd be better to reclaim this victim
637 * completely.
638 */
639 if (get_valid_blocks(sbi, segno, 1) != 0) {
640 phase = 2;
641 goto next_step;
642 }
643 }
644}
645
646static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
647 int gc_type, int type)
648{
649 struct sit_info *sit_i = SIT_I(sbi);
650 int ret;
651 mutex_lock(&sit_i->sentry_lock);
652 ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
653 mutex_unlock(&sit_i->sentry_lock);
654 return ret;
655}
656
657static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
658 struct list_head *ilist, int gc_type)
659{
660 struct page *sum_page;
661 struct f2fs_summary_block *sum;
662 struct blk_plug plug;
663
664 /* read segment summary of victim */
665 sum_page = get_sum_page(sbi, segno);
666
667 blk_start_plug(&plug);
668
669 sum = page_address(sum_page);
670
671 switch (GET_SUM_TYPE((&sum->footer))) {
672 case SUM_TYPE_NODE:
673 gc_node_segment(sbi, sum->entries, segno, gc_type);
674 break;
675 case SUM_TYPE_DATA:
676 gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
677 break;
678 }
679 blk_finish_plug(&plug);
680
681 stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
682 stat_inc_call_count(sbi->stat_info);
683
684 f2fs_put_page(sum_page, 1);
685}
686
687int f2fs_gc(struct f2fs_sb_info *sbi)
688{
689 struct list_head ilist;
690 unsigned int segno, i;
691 int gc_type = BG_GC;
692 int nfree = 0;
693 int ret = -1;
694
695 INIT_LIST_HEAD(&ilist);
696gc_more:
697 if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
698 goto stop;
699 if (unlikely(is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)))
700 goto stop;
701
702 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
703 gc_type = FG_GC;
704 write_checkpoint(sbi, false);
705 }
706
707 if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
708 goto stop;
709 ret = 0;
710
711 /* readahead multi ssa blocks those have contiguous address */
712 if (sbi->segs_per_sec > 1)
713 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), sbi->segs_per_sec,
714 META_SSA);
715
716 for (i = 0; i < sbi->segs_per_sec; i++)
717 do_garbage_collect(sbi, segno + i, &ilist, gc_type);
718
719 if (gc_type == FG_GC) {
720 sbi->cur_victim_sec = NULL_SEGNO;
721 nfree++;
722 WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
723 }
724
725 if (has_not_enough_free_secs(sbi, nfree))
726 goto gc_more;
727
728 if (gc_type == FG_GC)
729 write_checkpoint(sbi, false);
730stop:
731 mutex_unlock(&sbi->gc_mutex);
732
733 put_gc_inode(&ilist);
734 return ret;
735}
736
737void build_gc_manager(struct f2fs_sb_info *sbi)
738{
739 DIRTY_I(sbi)->v_ops = &default_v_ops;
740}
741
742int __init create_gc_caches(void)
743{
744 winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
745 sizeof(struct inode_entry));
746 if (!winode_slab)
747 return -ENOMEM;
748 return 0;
749}
750
751void destroy_gc_caches(void)
752{
753 kmem_cache_destroy(winode_slab);
754}