xref: /linux/fs/f2fs/gc.c (revision 52990390f91c1c39ca742fc8f390b29891d95127)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * fs/f2fs/gc.c
4  *
5  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
6  *             http://www.samsung.com/
7  */
8 #include <linux/fs.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/f2fs_fs.h>
12 #include <linux/kthread.h>
13 #include <linux/delay.h>
14 #include <linux/freezer.h>
15 #include <linux/sched/signal.h>
16 #include <linux/random.h>
17 #include <linux/sched/mm.h>
18 
19 #include "f2fs.h"
20 #include "node.h"
21 #include "segment.h"
22 #include "gc.h"
23 #include "iostat.h"
24 #include <trace/events/f2fs.h>
25 
26 static struct kmem_cache *victim_entry_slab;
27 
28 static unsigned int count_bits(const unsigned long *addr,
29 				unsigned int offset, unsigned int len);
30 
31 static int gc_thread_func(void *data)
32 {
33 	struct f2fs_sb_info *sbi = data;
34 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
35 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
36 	wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
37 	unsigned int wait_ms;
38 	struct f2fs_gc_control gc_control = {
39 		.victim_segno = NULL_SEGNO,
40 		.should_migrate_blocks = false,
41 		.err_gc_skipped = false };
42 
43 	wait_ms = gc_th->min_sleep_time;
44 
45 	set_freezable();
46 	do {
47 		bool sync_mode, foreground = false;
48 
49 		wait_event_interruptible_timeout(*wq,
50 				kthread_should_stop() || freezing(current) ||
51 				waitqueue_active(fggc_wq) ||
52 				gc_th->gc_wake,
53 				msecs_to_jiffies(wait_ms));
54 
55 		if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
56 			foreground = true;
57 
58 		/* give it a try one time */
59 		if (gc_th->gc_wake)
60 			gc_th->gc_wake = false;
61 
62 		if (try_to_freeze()) {
63 			stat_other_skip_bggc_count(sbi);
64 			continue;
65 		}
66 		if (kthread_should_stop())
67 			break;
68 
69 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
70 			increase_sleep_time(gc_th, &wait_ms);
71 			stat_other_skip_bggc_count(sbi);
72 			continue;
73 		}
74 
75 		if (time_to_inject(sbi, FAULT_CHECKPOINT))
76 			f2fs_stop_checkpoint(sbi, false,
77 					STOP_CP_REASON_FAULT_INJECT);
78 
79 		if (!sb_start_write_trylock(sbi->sb)) {
80 			stat_other_skip_bggc_count(sbi);
81 			continue;
82 		}
83 
84 		/*
85 		 * [GC triggering condition]
86 		 * 0. GC is not conducted currently.
87 		 * 1. There are enough dirty segments.
88 		 * 2. IO subsystem is idle by checking the # of writeback pages.
89 		 * 3. IO subsystem is idle by checking the # of requests in
90 		 *    bdev's request list.
91 		 *
92 		 * Note) We have to avoid triggering GCs frequently.
93 		 * Because it is possible that some segments can be
94 		 * invalidated soon after by user update or deletion.
95 		 * So, I'd like to wait some time to collect dirty segments.
96 		 */
97 		if (sbi->gc_mode == GC_URGENT_HIGH ||
98 				sbi->gc_mode == GC_URGENT_MID) {
99 			wait_ms = gc_th->urgent_sleep_time;
100 			f2fs_down_write(&sbi->gc_lock);
101 			goto do_gc;
102 		}
103 
104 		if (foreground) {
105 			f2fs_down_write(&sbi->gc_lock);
106 			goto do_gc;
107 		} else if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
108 			stat_other_skip_bggc_count(sbi);
109 			goto next;
110 		}
111 
112 		if (!is_idle(sbi, GC_TIME)) {
113 			increase_sleep_time(gc_th, &wait_ms);
114 			f2fs_up_write(&sbi->gc_lock);
115 			stat_io_skip_bggc_count(sbi);
116 			goto next;
117 		}
118 
119 		if (has_enough_invalid_blocks(sbi))
120 			decrease_sleep_time(gc_th, &wait_ms);
121 		else
122 			increase_sleep_time(gc_th, &wait_ms);
123 do_gc:
124 		if (!foreground)
125 			stat_inc_bggc_count(sbi->stat_info);
126 
127 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
128 
129 		/* foreground GC was been triggered via f2fs_balance_fs() */
130 		if (foreground)
131 			sync_mode = false;
132 
133 		gc_control.init_gc_type = sync_mode ? FG_GC : BG_GC;
134 		gc_control.no_bg_gc = foreground;
135 		gc_control.nr_free_secs = foreground ? 1 : 0;
136 
137 		/* if return value is not zero, no victim was selected */
138 		if (f2fs_gc(sbi, &gc_control)) {
139 			/* don't bother wait_ms by foreground gc */
140 			if (!foreground)
141 				wait_ms = gc_th->no_gc_sleep_time;
142 		} else {
143 			/* reset wait_ms to default sleep time */
144 			if (wait_ms == gc_th->no_gc_sleep_time)
145 				wait_ms = gc_th->min_sleep_time;
146 		}
147 
148 		if (foreground)
149 			wake_up_all(&gc_th->fggc_wq);
150 
151 		trace_f2fs_background_gc(sbi->sb, wait_ms,
152 				prefree_segments(sbi), free_segments(sbi));
153 
154 		/* balancing f2fs's metadata periodically */
155 		f2fs_balance_fs_bg(sbi, true);
156 next:
157 		if (sbi->gc_mode != GC_NORMAL) {
158 			spin_lock(&sbi->gc_remaining_trials_lock);
159 			if (sbi->gc_remaining_trials) {
160 				sbi->gc_remaining_trials--;
161 				if (!sbi->gc_remaining_trials)
162 					sbi->gc_mode = GC_NORMAL;
163 			}
164 			spin_unlock(&sbi->gc_remaining_trials_lock);
165 		}
166 		sb_end_write(sbi->sb);
167 
168 	} while (!kthread_should_stop());
169 	return 0;
170 }
171 
172 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
173 {
174 	struct f2fs_gc_kthread *gc_th;
175 	dev_t dev = sbi->sb->s_bdev->bd_dev;
176 
177 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
178 	if (!gc_th)
179 		return -ENOMEM;
180 
181 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
182 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
183 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
184 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
185 
186 	gc_th->gc_wake = false;
187 
188 	sbi->gc_thread = gc_th;
189 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
190 	init_waitqueue_head(&sbi->gc_thread->fggc_wq);
191 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
192 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
193 	if (IS_ERR(gc_th->f2fs_gc_task)) {
194 		int err = PTR_ERR(gc_th->f2fs_gc_task);
195 
196 		kfree(gc_th);
197 		sbi->gc_thread = NULL;
198 		return err;
199 	}
200 
201 	return 0;
202 }
203 
204 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
205 {
206 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
207 
208 	if (!gc_th)
209 		return;
210 	kthread_stop(gc_th->f2fs_gc_task);
211 	wake_up_all(&gc_th->fggc_wq);
212 	kfree(gc_th);
213 	sbi->gc_thread = NULL;
214 }
215 
216 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
217 {
218 	int gc_mode;
219 
220 	if (gc_type == BG_GC) {
221 		if (sbi->am.atgc_enabled)
222 			gc_mode = GC_AT;
223 		else
224 			gc_mode = GC_CB;
225 	} else {
226 		gc_mode = GC_GREEDY;
227 	}
228 
229 	switch (sbi->gc_mode) {
230 	case GC_IDLE_CB:
231 		gc_mode = GC_CB;
232 		break;
233 	case GC_IDLE_GREEDY:
234 	case GC_URGENT_HIGH:
235 		gc_mode = GC_GREEDY;
236 		break;
237 	case GC_IDLE_AT:
238 		gc_mode = GC_AT;
239 		break;
240 	}
241 
242 	return gc_mode;
243 }
244 
245 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
246 			int type, struct victim_sel_policy *p)
247 {
248 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
249 
250 	if (p->alloc_mode == SSR) {
251 		p->gc_mode = GC_GREEDY;
252 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
253 		p->max_search = dirty_i->nr_dirty[type];
254 		p->ofs_unit = 1;
255 	} else if (p->alloc_mode == AT_SSR) {
256 		p->gc_mode = GC_GREEDY;
257 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
258 		p->max_search = dirty_i->nr_dirty[type];
259 		p->ofs_unit = 1;
260 	} else {
261 		p->gc_mode = select_gc_type(sbi, gc_type);
262 		p->ofs_unit = sbi->segs_per_sec;
263 		if (__is_large_section(sbi)) {
264 			p->dirty_bitmap = dirty_i->dirty_secmap;
265 			p->max_search = count_bits(p->dirty_bitmap,
266 						0, MAIN_SECS(sbi));
267 		} else {
268 			p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
269 			p->max_search = dirty_i->nr_dirty[DIRTY];
270 		}
271 	}
272 
273 	/*
274 	 * adjust candidates range, should select all dirty segments for
275 	 * foreground GC and urgent GC cases.
276 	 */
277 	if (gc_type != FG_GC &&
278 			(sbi->gc_mode != GC_URGENT_HIGH) &&
279 			(p->gc_mode != GC_AT && p->alloc_mode != AT_SSR) &&
280 			p->max_search > sbi->max_victim_search)
281 		p->max_search = sbi->max_victim_search;
282 
283 	/* let's select beginning hot/small space first in no_heap mode*/
284 	if (f2fs_need_rand_seg(sbi))
285 		p->offset = get_random_u32_below(MAIN_SECS(sbi) * sbi->segs_per_sec);
286 	else if (test_opt(sbi, NOHEAP) &&
287 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
288 		p->offset = 0;
289 	else
290 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
291 }
292 
293 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
294 				struct victim_sel_policy *p)
295 {
296 	/* SSR allocates in a segment unit */
297 	if (p->alloc_mode == SSR)
298 		return sbi->blocks_per_seg;
299 	else if (p->alloc_mode == AT_SSR)
300 		return UINT_MAX;
301 
302 	/* LFS */
303 	if (p->gc_mode == GC_GREEDY)
304 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
305 	else if (p->gc_mode == GC_CB)
306 		return UINT_MAX;
307 	else if (p->gc_mode == GC_AT)
308 		return UINT_MAX;
309 	else /* No other gc_mode */
310 		return 0;
311 }
312 
313 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
314 {
315 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
316 	unsigned int secno;
317 
318 	/*
319 	 * If the gc_type is FG_GC, we can select victim segments
320 	 * selected by background GC before.
321 	 * Those segments guarantee they have small valid blocks.
322 	 */
323 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
324 		if (sec_usage_check(sbi, secno))
325 			continue;
326 		clear_bit(secno, dirty_i->victim_secmap);
327 		return GET_SEG_FROM_SEC(sbi, secno);
328 	}
329 	return NULL_SEGNO;
330 }
331 
332 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
333 {
334 	struct sit_info *sit_i = SIT_I(sbi);
335 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
336 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
337 	unsigned long long mtime = 0;
338 	unsigned int vblocks;
339 	unsigned char age = 0;
340 	unsigned char u;
341 	unsigned int i;
342 	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
343 
344 	for (i = 0; i < usable_segs_per_sec; i++)
345 		mtime += get_seg_entry(sbi, start + i)->mtime;
346 	vblocks = get_valid_blocks(sbi, segno, true);
347 
348 	mtime = div_u64(mtime, usable_segs_per_sec);
349 	vblocks = div_u64(vblocks, usable_segs_per_sec);
350 
351 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
352 
353 	/* Handle if the system time has changed by the user */
354 	if (mtime < sit_i->min_mtime)
355 		sit_i->min_mtime = mtime;
356 	if (mtime > sit_i->max_mtime)
357 		sit_i->max_mtime = mtime;
358 	if (sit_i->max_mtime != sit_i->min_mtime)
359 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
360 				sit_i->max_mtime - sit_i->min_mtime);
361 
362 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
363 }
364 
365 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
366 			unsigned int segno, struct victim_sel_policy *p)
367 {
368 	if (p->alloc_mode == SSR)
369 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
370 
371 	/* alloc_mode == LFS */
372 	if (p->gc_mode == GC_GREEDY)
373 		return get_valid_blocks(sbi, segno, true);
374 	else if (p->gc_mode == GC_CB)
375 		return get_cb_cost(sbi, segno);
376 
377 	f2fs_bug_on(sbi, 1);
378 	return 0;
379 }
380 
381 static unsigned int count_bits(const unsigned long *addr,
382 				unsigned int offset, unsigned int len)
383 {
384 	unsigned int end = offset + len, sum = 0;
385 
386 	while (offset < end) {
387 		if (test_bit(offset++, addr))
388 			++sum;
389 	}
390 	return sum;
391 }
392 
393 static bool f2fs_check_victim_tree(struct f2fs_sb_info *sbi,
394 				struct rb_root_cached *root)
395 {
396 #ifdef CONFIG_F2FS_CHECK_FS
397 	struct rb_node *cur = rb_first_cached(root), *next;
398 	struct victim_entry *cur_ve, *next_ve;
399 
400 	while (cur) {
401 		next = rb_next(cur);
402 		if (!next)
403 			return true;
404 
405 		cur_ve = rb_entry(cur, struct victim_entry, rb_node);
406 		next_ve = rb_entry(next, struct victim_entry, rb_node);
407 
408 		if (cur_ve->mtime > next_ve->mtime) {
409 			f2fs_info(sbi, "broken victim_rbtree, "
410 				"cur_mtime(%llu) next_mtime(%llu)",
411 				cur_ve->mtime, next_ve->mtime);
412 			return false;
413 		}
414 		cur = next;
415 	}
416 #endif
417 	return true;
418 }
419 
420 static struct victim_entry *__lookup_victim_entry(struct f2fs_sb_info *sbi,
421 					unsigned long long mtime)
422 {
423 	struct atgc_management *am = &sbi->am;
424 	struct rb_node *node = am->root.rb_root.rb_node;
425 	struct victim_entry *ve = NULL;
426 
427 	while (node) {
428 		ve = rb_entry(node, struct victim_entry, rb_node);
429 
430 		if (mtime < ve->mtime)
431 			node = node->rb_left;
432 		else
433 			node = node->rb_right;
434 	}
435 	return ve;
436 }
437 
438 static struct victim_entry *__create_victim_entry(struct f2fs_sb_info *sbi,
439 		unsigned long long mtime, unsigned int segno)
440 {
441 	struct atgc_management *am = &sbi->am;
442 	struct victim_entry *ve;
443 
444 	ve =  f2fs_kmem_cache_alloc(victim_entry_slab, GFP_NOFS, true, NULL);
445 
446 	ve->mtime = mtime;
447 	ve->segno = segno;
448 
449 	list_add_tail(&ve->list, &am->victim_list);
450 	am->victim_count++;
451 
452 	return ve;
453 }
454 
455 static void __insert_victim_entry(struct f2fs_sb_info *sbi,
456 				unsigned long long mtime, unsigned int segno)
457 {
458 	struct atgc_management *am = &sbi->am;
459 	struct rb_root_cached *root = &am->root;
460 	struct rb_node **p = &root->rb_root.rb_node;
461 	struct rb_node *parent = NULL;
462 	struct victim_entry *ve;
463 	bool left_most = true;
464 
465 	/* look up rb tree to find parent node */
466 	while (*p) {
467 		parent = *p;
468 		ve = rb_entry(parent, struct victim_entry, rb_node);
469 
470 		if (mtime < ve->mtime) {
471 			p = &(*p)->rb_left;
472 		} else {
473 			p = &(*p)->rb_right;
474 			left_most = false;
475 		}
476 	}
477 
478 	ve = __create_victim_entry(sbi, mtime, segno);
479 
480 	rb_link_node(&ve->rb_node, parent, p);
481 	rb_insert_color_cached(&ve->rb_node, root, left_most);
482 }
483 
484 static void add_victim_entry(struct f2fs_sb_info *sbi,
485 				struct victim_sel_policy *p, unsigned int segno)
486 {
487 	struct sit_info *sit_i = SIT_I(sbi);
488 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
489 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
490 	unsigned long long mtime = 0;
491 	unsigned int i;
492 
493 	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
494 		if (p->gc_mode == GC_AT &&
495 			get_valid_blocks(sbi, segno, true) == 0)
496 			return;
497 	}
498 
499 	for (i = 0; i < sbi->segs_per_sec; i++)
500 		mtime += get_seg_entry(sbi, start + i)->mtime;
501 	mtime = div_u64(mtime, sbi->segs_per_sec);
502 
503 	/* Handle if the system time has changed by the user */
504 	if (mtime < sit_i->min_mtime)
505 		sit_i->min_mtime = mtime;
506 	if (mtime > sit_i->max_mtime)
507 		sit_i->max_mtime = mtime;
508 	if (mtime < sit_i->dirty_min_mtime)
509 		sit_i->dirty_min_mtime = mtime;
510 	if (mtime > sit_i->dirty_max_mtime)
511 		sit_i->dirty_max_mtime = mtime;
512 
513 	/* don't choose young section as candidate */
514 	if (sit_i->dirty_max_mtime - mtime < p->age_threshold)
515 		return;
516 
517 	__insert_victim_entry(sbi, mtime, segno);
518 }
519 
520 static void atgc_lookup_victim(struct f2fs_sb_info *sbi,
521 						struct victim_sel_policy *p)
522 {
523 	struct sit_info *sit_i = SIT_I(sbi);
524 	struct atgc_management *am = &sbi->am;
525 	struct rb_root_cached *root = &am->root;
526 	struct rb_node *node;
527 	struct victim_entry *ve;
528 	unsigned long long total_time;
529 	unsigned long long age, u, accu;
530 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
531 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
532 	unsigned int sec_blocks = CAP_BLKS_PER_SEC(sbi);
533 	unsigned int vblocks;
534 	unsigned int dirty_threshold = max(am->max_candidate_count,
535 					am->candidate_ratio *
536 					am->victim_count / 100);
537 	unsigned int age_weight = am->age_weight;
538 	unsigned int cost;
539 	unsigned int iter = 0;
540 
541 	if (max_mtime < min_mtime)
542 		return;
543 
544 	max_mtime += 1;
545 	total_time = max_mtime - min_mtime;
546 
547 	accu = div64_u64(ULLONG_MAX, total_time);
548 	accu = min_t(unsigned long long, div_u64(accu, 100),
549 					DEFAULT_ACCURACY_CLASS);
550 
551 	node = rb_first_cached(root);
552 next:
553 	ve = rb_entry_safe(node, struct victim_entry, rb_node);
554 	if (!ve)
555 		return;
556 
557 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
558 		goto skip;
559 
560 	/* age = 10000 * x% * 60 */
561 	age = div64_u64(accu * (max_mtime - ve->mtime), total_time) *
562 								age_weight;
563 
564 	vblocks = get_valid_blocks(sbi, ve->segno, true);
565 	f2fs_bug_on(sbi, !vblocks || vblocks == sec_blocks);
566 
567 	/* u = 10000 * x% * 40 */
568 	u = div64_u64(accu * (sec_blocks - vblocks), sec_blocks) *
569 							(100 - age_weight);
570 
571 	f2fs_bug_on(sbi, age + u >= UINT_MAX);
572 
573 	cost = UINT_MAX - (age + u);
574 	iter++;
575 
576 	if (cost < p->min_cost ||
577 			(cost == p->min_cost && age > p->oldest_age)) {
578 		p->min_cost = cost;
579 		p->oldest_age = age;
580 		p->min_segno = ve->segno;
581 	}
582 skip:
583 	if (iter < dirty_threshold) {
584 		node = rb_next(node);
585 		goto next;
586 	}
587 }
588 
589 /*
590  * select candidates around source section in range of
591  * [target - dirty_threshold, target + dirty_threshold]
592  */
593 static void atssr_lookup_victim(struct f2fs_sb_info *sbi,
594 						struct victim_sel_policy *p)
595 {
596 	struct sit_info *sit_i = SIT_I(sbi);
597 	struct atgc_management *am = &sbi->am;
598 	struct victim_entry *ve;
599 	unsigned long long age;
600 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
601 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
602 	unsigned int seg_blocks = sbi->blocks_per_seg;
603 	unsigned int vblocks;
604 	unsigned int dirty_threshold = max(am->max_candidate_count,
605 					am->candidate_ratio *
606 					am->victim_count / 100);
607 	unsigned int cost, iter;
608 	int stage = 0;
609 
610 	if (max_mtime < min_mtime)
611 		return;
612 	max_mtime += 1;
613 next_stage:
614 	iter = 0;
615 	ve = __lookup_victim_entry(sbi, p->age);
616 next_node:
617 	if (!ve) {
618 		if (stage++ == 0)
619 			goto next_stage;
620 		return;
621 	}
622 
623 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
624 		goto skip_node;
625 
626 	age = max_mtime - ve->mtime;
627 
628 	vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
629 	f2fs_bug_on(sbi, !vblocks);
630 
631 	/* rare case */
632 	if (vblocks == seg_blocks)
633 		goto skip_node;
634 
635 	iter++;
636 
637 	age = max_mtime - abs(p->age - age);
638 	cost = UINT_MAX - vblocks;
639 
640 	if (cost < p->min_cost ||
641 			(cost == p->min_cost && age > p->oldest_age)) {
642 		p->min_cost = cost;
643 		p->oldest_age = age;
644 		p->min_segno = ve->segno;
645 	}
646 skip_node:
647 	if (iter < dirty_threshold) {
648 		ve = rb_entry(stage == 0 ? rb_prev(&ve->rb_node) :
649 					rb_next(&ve->rb_node),
650 					struct victim_entry, rb_node);
651 		goto next_node;
652 	}
653 
654 	if (stage++ == 0)
655 		goto next_stage;
656 }
657 
658 static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
659 						struct victim_sel_policy *p)
660 {
661 	f2fs_bug_on(sbi, !f2fs_check_victim_tree(sbi, &sbi->am.root));
662 
663 	if (p->gc_mode == GC_AT)
664 		atgc_lookup_victim(sbi, p);
665 	else if (p->alloc_mode == AT_SSR)
666 		atssr_lookup_victim(sbi, p);
667 	else
668 		f2fs_bug_on(sbi, 1);
669 }
670 
671 static void release_victim_entry(struct f2fs_sb_info *sbi)
672 {
673 	struct atgc_management *am = &sbi->am;
674 	struct victim_entry *ve, *tmp;
675 
676 	list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
677 		list_del(&ve->list);
678 		kmem_cache_free(victim_entry_slab, ve);
679 		am->victim_count--;
680 	}
681 
682 	am->root = RB_ROOT_CACHED;
683 
684 	f2fs_bug_on(sbi, am->victim_count);
685 	f2fs_bug_on(sbi, !list_empty(&am->victim_list));
686 }
687 
688 static bool f2fs_pin_section(struct f2fs_sb_info *sbi, unsigned int segno)
689 {
690 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
691 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
692 
693 	if (!dirty_i->enable_pin_section)
694 		return false;
695 	if (!test_and_set_bit(secno, dirty_i->pinned_secmap))
696 		dirty_i->pinned_secmap_cnt++;
697 	return true;
698 }
699 
700 static bool f2fs_pinned_section_exists(struct dirty_seglist_info *dirty_i)
701 {
702 	return dirty_i->pinned_secmap_cnt;
703 }
704 
705 static bool f2fs_section_is_pinned(struct dirty_seglist_info *dirty_i,
706 						unsigned int secno)
707 {
708 	return dirty_i->enable_pin_section &&
709 		f2fs_pinned_section_exists(dirty_i) &&
710 		test_bit(secno, dirty_i->pinned_secmap);
711 }
712 
713 static void f2fs_unpin_all_sections(struct f2fs_sb_info *sbi, bool enable)
714 {
715 	unsigned int bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
716 
717 	if (f2fs_pinned_section_exists(DIRTY_I(sbi))) {
718 		memset(DIRTY_I(sbi)->pinned_secmap, 0, bitmap_size);
719 		DIRTY_I(sbi)->pinned_secmap_cnt = 0;
720 	}
721 	DIRTY_I(sbi)->enable_pin_section = enable;
722 }
723 
724 static int f2fs_gc_pinned_control(struct inode *inode, int gc_type,
725 							unsigned int segno)
726 {
727 	if (!f2fs_is_pinned_file(inode))
728 		return 0;
729 	if (gc_type != FG_GC)
730 		return -EBUSY;
731 	if (!f2fs_pin_section(F2FS_I_SB(inode), segno))
732 		f2fs_pin_file_control(inode, true);
733 	return -EAGAIN;
734 }
735 
736 /*
737  * This function is called from two paths.
738  * One is garbage collection and the other is SSR segment selection.
739  * When it is called during GC, it just gets a victim segment
740  * and it does not remove it from dirty seglist.
741  * When it is called from SSR segment selection, it finds a segment
742  * which has minimum valid blocks and removes it from dirty seglist.
743  */
744 int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,
745 			int gc_type, int type, char alloc_mode,
746 			unsigned long long age)
747 {
748 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
749 	struct sit_info *sm = SIT_I(sbi);
750 	struct victim_sel_policy p;
751 	unsigned int secno, last_victim;
752 	unsigned int last_segment;
753 	unsigned int nsearched;
754 	bool is_atgc;
755 	int ret = 0;
756 
757 	mutex_lock(&dirty_i->seglist_lock);
758 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
759 
760 	p.alloc_mode = alloc_mode;
761 	p.age = age;
762 	p.age_threshold = sbi->am.age_threshold;
763 
764 retry:
765 	select_policy(sbi, gc_type, type, &p);
766 	p.min_segno = NULL_SEGNO;
767 	p.oldest_age = 0;
768 	p.min_cost = get_max_cost(sbi, &p);
769 
770 	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
771 	nsearched = 0;
772 
773 	if (is_atgc)
774 		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
775 
776 	if (*result != NULL_SEGNO) {
777 		if (!get_valid_blocks(sbi, *result, false)) {
778 			ret = -ENODATA;
779 			goto out;
780 		}
781 
782 		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
783 			ret = -EBUSY;
784 		else
785 			p.min_segno = *result;
786 		goto out;
787 	}
788 
789 	ret = -ENODATA;
790 	if (p.max_search == 0)
791 		goto out;
792 
793 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
794 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
795 			p.min_segno = sbi->next_victim_seg[BG_GC];
796 			*result = p.min_segno;
797 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
798 			goto got_result;
799 		}
800 		if (gc_type == FG_GC &&
801 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
802 			p.min_segno = sbi->next_victim_seg[FG_GC];
803 			*result = p.min_segno;
804 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
805 			goto got_result;
806 		}
807 	}
808 
809 	last_victim = sm->last_victim[p.gc_mode];
810 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
811 		p.min_segno = check_bg_victims(sbi);
812 		if (p.min_segno != NULL_SEGNO)
813 			goto got_it;
814 	}
815 
816 	while (1) {
817 		unsigned long cost, *dirty_bitmap;
818 		unsigned int unit_no, segno;
819 
820 		dirty_bitmap = p.dirty_bitmap;
821 		unit_no = find_next_bit(dirty_bitmap,
822 				last_segment / p.ofs_unit,
823 				p.offset / p.ofs_unit);
824 		segno = unit_no * p.ofs_unit;
825 		if (segno >= last_segment) {
826 			if (sm->last_victim[p.gc_mode]) {
827 				last_segment =
828 					sm->last_victim[p.gc_mode];
829 				sm->last_victim[p.gc_mode] = 0;
830 				p.offset = 0;
831 				continue;
832 			}
833 			break;
834 		}
835 
836 		p.offset = segno + p.ofs_unit;
837 		nsearched++;
838 
839 #ifdef CONFIG_F2FS_CHECK_FS
840 		/*
841 		 * skip selecting the invalid segno (that is failed due to block
842 		 * validity check failure during GC) to avoid endless GC loop in
843 		 * such cases.
844 		 */
845 		if (test_bit(segno, sm->invalid_segmap))
846 			goto next;
847 #endif
848 
849 		secno = GET_SEC_FROM_SEG(sbi, segno);
850 
851 		if (sec_usage_check(sbi, secno))
852 			goto next;
853 
854 		/* Don't touch checkpointed data */
855 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
856 			if (p.alloc_mode == LFS) {
857 				/*
858 				 * LFS is set to find source section during GC.
859 				 * The victim should have no checkpointed data.
860 				 */
861 				if (get_ckpt_valid_blocks(sbi, segno, true))
862 					goto next;
863 			} else {
864 				/*
865 				 * SSR | AT_SSR are set to find target segment
866 				 * for writes which can be full by checkpointed
867 				 * and newly written blocks.
868 				 */
869 				if (!f2fs_segment_has_free_slot(sbi, segno))
870 					goto next;
871 			}
872 		}
873 
874 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
875 			goto next;
876 
877 		if (gc_type == FG_GC && f2fs_section_is_pinned(dirty_i, secno))
878 			goto next;
879 
880 		if (is_atgc) {
881 			add_victim_entry(sbi, &p, segno);
882 			goto next;
883 		}
884 
885 		cost = get_gc_cost(sbi, segno, &p);
886 
887 		if (p.min_cost > cost) {
888 			p.min_segno = segno;
889 			p.min_cost = cost;
890 		}
891 next:
892 		if (nsearched >= p.max_search) {
893 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
894 				sm->last_victim[p.gc_mode] =
895 					last_victim + p.ofs_unit;
896 			else
897 				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
898 			sm->last_victim[p.gc_mode] %=
899 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
900 			break;
901 		}
902 	}
903 
904 	/* get victim for GC_AT/AT_SSR */
905 	if (is_atgc) {
906 		lookup_victim_by_age(sbi, &p);
907 		release_victim_entry(sbi);
908 	}
909 
910 	if (is_atgc && p.min_segno == NULL_SEGNO &&
911 			sm->elapsed_time < p.age_threshold) {
912 		p.age_threshold = 0;
913 		goto retry;
914 	}
915 
916 	if (p.min_segno != NULL_SEGNO) {
917 got_it:
918 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
919 got_result:
920 		if (p.alloc_mode == LFS) {
921 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
922 			if (gc_type == FG_GC)
923 				sbi->cur_victim_sec = secno;
924 			else
925 				set_bit(secno, dirty_i->victim_secmap);
926 		}
927 		ret = 0;
928 
929 	}
930 out:
931 	if (p.min_segno != NULL_SEGNO)
932 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
933 				sbi->cur_victim_sec,
934 				prefree_segments(sbi), free_segments(sbi));
935 	mutex_unlock(&dirty_i->seglist_lock);
936 
937 	return ret;
938 }
939 
940 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
941 {
942 	struct inode_entry *ie;
943 
944 	ie = radix_tree_lookup(&gc_list->iroot, ino);
945 	if (ie)
946 		return ie->inode;
947 	return NULL;
948 }
949 
950 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
951 {
952 	struct inode_entry *new_ie;
953 
954 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
955 		iput(inode);
956 		return;
957 	}
958 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab,
959 					GFP_NOFS, true, NULL);
960 	new_ie->inode = inode;
961 
962 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
963 	list_add_tail(&new_ie->list, &gc_list->ilist);
964 }
965 
966 static void put_gc_inode(struct gc_inode_list *gc_list)
967 {
968 	struct inode_entry *ie, *next_ie;
969 
970 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
971 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
972 		iput(ie->inode);
973 		list_del(&ie->list);
974 		kmem_cache_free(f2fs_inode_entry_slab, ie);
975 	}
976 }
977 
978 static int check_valid_map(struct f2fs_sb_info *sbi,
979 				unsigned int segno, int offset)
980 {
981 	struct sit_info *sit_i = SIT_I(sbi);
982 	struct seg_entry *sentry;
983 	int ret;
984 
985 	down_read(&sit_i->sentry_lock);
986 	sentry = get_seg_entry(sbi, segno);
987 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
988 	up_read(&sit_i->sentry_lock);
989 	return ret;
990 }
991 
992 /*
993  * This function compares node address got in summary with that in NAT.
994  * On validity, copy that node with cold status, otherwise (invalid node)
995  * ignore that.
996  */
997 static int gc_node_segment(struct f2fs_sb_info *sbi,
998 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
999 {
1000 	struct f2fs_summary *entry;
1001 	block_t start_addr;
1002 	int off;
1003 	int phase = 0;
1004 	bool fggc = (gc_type == FG_GC);
1005 	int submitted = 0;
1006 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1007 
1008 	start_addr = START_BLOCK(sbi, segno);
1009 
1010 next_step:
1011 	entry = sum;
1012 
1013 	if (fggc && phase == 2)
1014 		atomic_inc(&sbi->wb_sync_req[NODE]);
1015 
1016 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1017 		nid_t nid = le32_to_cpu(entry->nid);
1018 		struct page *node_page;
1019 		struct node_info ni;
1020 		int err;
1021 
1022 		/* stop BG_GC if there is not enough free sections. */
1023 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
1024 			return submitted;
1025 
1026 		if (check_valid_map(sbi, segno, off) == 0)
1027 			continue;
1028 
1029 		if (phase == 0) {
1030 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1031 							META_NAT, true);
1032 			continue;
1033 		}
1034 
1035 		if (phase == 1) {
1036 			f2fs_ra_node_page(sbi, nid);
1037 			continue;
1038 		}
1039 
1040 		/* phase == 2 */
1041 		node_page = f2fs_get_node_page(sbi, nid);
1042 		if (IS_ERR(node_page))
1043 			continue;
1044 
1045 		/* block may become invalid during f2fs_get_node_page */
1046 		if (check_valid_map(sbi, segno, off) == 0) {
1047 			f2fs_put_page(node_page, 1);
1048 			continue;
1049 		}
1050 
1051 		if (f2fs_get_node_info(sbi, nid, &ni, false)) {
1052 			f2fs_put_page(node_page, 1);
1053 			continue;
1054 		}
1055 
1056 		if (ni.blk_addr != start_addr + off) {
1057 			f2fs_put_page(node_page, 1);
1058 			continue;
1059 		}
1060 
1061 		err = f2fs_move_node_page(node_page, gc_type);
1062 		if (!err && gc_type == FG_GC)
1063 			submitted++;
1064 		stat_inc_node_blk_count(sbi, 1, gc_type);
1065 	}
1066 
1067 	if (++phase < 3)
1068 		goto next_step;
1069 
1070 	if (fggc)
1071 		atomic_dec(&sbi->wb_sync_req[NODE]);
1072 	return submitted;
1073 }
1074 
1075 /*
1076  * Calculate start block index indicating the given node offset.
1077  * Be careful, caller should give this node offset only indicating direct node
1078  * blocks. If any node offsets, which point the other types of node blocks such
1079  * as indirect or double indirect node blocks, are given, it must be a caller's
1080  * bug.
1081  */
1082 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
1083 {
1084 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
1085 	unsigned int bidx;
1086 
1087 	if (node_ofs == 0)
1088 		return 0;
1089 
1090 	if (node_ofs <= 2) {
1091 		bidx = node_ofs - 1;
1092 	} else if (node_ofs <= indirect_blks) {
1093 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
1094 
1095 		bidx = node_ofs - 2 - dec;
1096 	} else {
1097 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
1098 
1099 		bidx = node_ofs - 5 - dec;
1100 	}
1101 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
1102 }
1103 
1104 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1105 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
1106 {
1107 	struct page *node_page;
1108 	nid_t nid;
1109 	unsigned int ofs_in_node, max_addrs, base;
1110 	block_t source_blkaddr;
1111 
1112 	nid = le32_to_cpu(sum->nid);
1113 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
1114 
1115 	node_page = f2fs_get_node_page(sbi, nid);
1116 	if (IS_ERR(node_page))
1117 		return false;
1118 
1119 	if (f2fs_get_node_info(sbi, nid, dni, false)) {
1120 		f2fs_put_page(node_page, 1);
1121 		return false;
1122 	}
1123 
1124 	if (sum->version != dni->version) {
1125 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
1126 			  __func__);
1127 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1128 	}
1129 
1130 	if (f2fs_check_nid_range(sbi, dni->ino)) {
1131 		f2fs_put_page(node_page, 1);
1132 		return false;
1133 	}
1134 
1135 	if (IS_INODE(node_page)) {
1136 		base = offset_in_addr(F2FS_INODE(node_page));
1137 		max_addrs = DEF_ADDRS_PER_INODE;
1138 	} else {
1139 		base = 0;
1140 		max_addrs = DEF_ADDRS_PER_BLOCK;
1141 	}
1142 
1143 	if (base + ofs_in_node >= max_addrs) {
1144 		f2fs_err(sbi, "Inconsistent blkaddr offset: base:%u, ofs_in_node:%u, max:%u, ino:%u, nid:%u",
1145 			base, ofs_in_node, max_addrs, dni->ino, dni->nid);
1146 		f2fs_put_page(node_page, 1);
1147 		return false;
1148 	}
1149 
1150 	*nofs = ofs_of_node(node_page);
1151 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
1152 	f2fs_put_page(node_page, 1);
1153 
1154 	if (source_blkaddr != blkaddr) {
1155 #ifdef CONFIG_F2FS_CHECK_FS
1156 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
1157 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
1158 
1159 		if (unlikely(check_valid_map(sbi, segno, offset))) {
1160 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
1161 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u",
1162 					 blkaddr, source_blkaddr, segno);
1163 				set_sbi_flag(sbi, SBI_NEED_FSCK);
1164 			}
1165 		}
1166 #endif
1167 		return false;
1168 	}
1169 	return true;
1170 }
1171 
1172 static int ra_data_block(struct inode *inode, pgoff_t index)
1173 {
1174 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1175 	struct address_space *mapping = inode->i_mapping;
1176 	struct dnode_of_data dn;
1177 	struct page *page;
1178 	struct f2fs_io_info fio = {
1179 		.sbi = sbi,
1180 		.ino = inode->i_ino,
1181 		.type = DATA,
1182 		.temp = COLD,
1183 		.op = REQ_OP_READ,
1184 		.op_flags = 0,
1185 		.encrypted_page = NULL,
1186 		.in_list = 0,
1187 		.retry = 0,
1188 	};
1189 	int err;
1190 
1191 	page = f2fs_grab_cache_page(mapping, index, true);
1192 	if (!page)
1193 		return -ENOMEM;
1194 
1195 	if (f2fs_lookup_read_extent_cache_block(inode, index,
1196 						&dn.data_blkaddr)) {
1197 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1198 						DATA_GENERIC_ENHANCE_READ))) {
1199 			err = -EFSCORRUPTED;
1200 			f2fs_handle_error(sbi, ERROR_INVALID_BLKADDR);
1201 			goto put_page;
1202 		}
1203 		goto got_it;
1204 	}
1205 
1206 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1207 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
1208 	if (err)
1209 		goto put_page;
1210 	f2fs_put_dnode(&dn);
1211 
1212 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
1213 		err = -ENOENT;
1214 		goto put_page;
1215 	}
1216 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1217 						DATA_GENERIC_ENHANCE))) {
1218 		err = -EFSCORRUPTED;
1219 		f2fs_handle_error(sbi, ERROR_INVALID_BLKADDR);
1220 		goto put_page;
1221 	}
1222 got_it:
1223 	/* read page */
1224 	fio.page = page;
1225 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1226 
1227 	/*
1228 	 * don't cache encrypted data into meta inode until previous dirty
1229 	 * data were writebacked to avoid racing between GC and flush.
1230 	 */
1231 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1232 
1233 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1234 
1235 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
1236 					dn.data_blkaddr,
1237 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
1238 	if (!fio.encrypted_page) {
1239 		err = -ENOMEM;
1240 		goto put_page;
1241 	}
1242 
1243 	err = f2fs_submit_page_bio(&fio);
1244 	if (err)
1245 		goto put_encrypted_page;
1246 	f2fs_put_page(fio.encrypted_page, 0);
1247 	f2fs_put_page(page, 1);
1248 
1249 	f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
1250 	f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1251 
1252 	return 0;
1253 put_encrypted_page:
1254 	f2fs_put_page(fio.encrypted_page, 1);
1255 put_page:
1256 	f2fs_put_page(page, 1);
1257 	return err;
1258 }
1259 
1260 /*
1261  * Move data block via META_MAPPING while keeping locked data page.
1262  * This can be used to move blocks, aka LBAs, directly on disk.
1263  */
1264 static int move_data_block(struct inode *inode, block_t bidx,
1265 				int gc_type, unsigned int segno, int off)
1266 {
1267 	struct f2fs_io_info fio = {
1268 		.sbi = F2FS_I_SB(inode),
1269 		.ino = inode->i_ino,
1270 		.type = DATA,
1271 		.temp = COLD,
1272 		.op = REQ_OP_READ,
1273 		.op_flags = 0,
1274 		.encrypted_page = NULL,
1275 		.in_list = 0,
1276 		.retry = 0,
1277 	};
1278 	struct dnode_of_data dn;
1279 	struct f2fs_summary sum;
1280 	struct node_info ni;
1281 	struct page *page, *mpage;
1282 	block_t newaddr;
1283 	int err = 0;
1284 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
1285 	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
1286 				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
1287 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
1288 
1289 	/* do not read out */
1290 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
1291 	if (!page)
1292 		return -ENOMEM;
1293 
1294 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1295 		err = -ENOENT;
1296 		goto out;
1297 	}
1298 
1299 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1300 	if (err)
1301 		goto out;
1302 
1303 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1304 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
1305 	if (err)
1306 		goto out;
1307 
1308 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
1309 		ClearPageUptodate(page);
1310 		err = -ENOENT;
1311 		goto put_out;
1312 	}
1313 
1314 	/*
1315 	 * don't cache encrypted data into meta inode until previous dirty
1316 	 * data were writebacked to avoid racing between GC and flush.
1317 	 */
1318 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1319 
1320 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1321 
1322 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni, false);
1323 	if (err)
1324 		goto put_out;
1325 
1326 	/* read page */
1327 	fio.page = page;
1328 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1329 
1330 	if (lfs_mode)
1331 		f2fs_down_write(&fio.sbi->io_order_lock);
1332 
1333 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
1334 					fio.old_blkaddr, false);
1335 	if (!mpage) {
1336 		err = -ENOMEM;
1337 		goto up_out;
1338 	}
1339 
1340 	fio.encrypted_page = mpage;
1341 
1342 	/* read source block in mpage */
1343 	if (!PageUptodate(mpage)) {
1344 		err = f2fs_submit_page_bio(&fio);
1345 		if (err) {
1346 			f2fs_put_page(mpage, 1);
1347 			goto up_out;
1348 		}
1349 
1350 		f2fs_update_iostat(fio.sbi, inode, FS_DATA_READ_IO,
1351 							F2FS_BLKSIZE);
1352 		f2fs_update_iostat(fio.sbi, NULL, FS_GDATA_READ_IO,
1353 							F2FS_BLKSIZE);
1354 
1355 		lock_page(mpage);
1356 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
1357 						!PageUptodate(mpage))) {
1358 			err = -EIO;
1359 			f2fs_put_page(mpage, 1);
1360 			goto up_out;
1361 		}
1362 	}
1363 
1364 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
1365 
1366 	/* allocate block address */
1367 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
1368 				&sum, type, NULL);
1369 
1370 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
1371 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
1372 	if (!fio.encrypted_page) {
1373 		err = -ENOMEM;
1374 		f2fs_put_page(mpage, 1);
1375 		goto recover_block;
1376 	}
1377 
1378 	/* write target block */
1379 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
1380 	memcpy(page_address(fio.encrypted_page),
1381 				page_address(mpage), PAGE_SIZE);
1382 	f2fs_put_page(mpage, 1);
1383 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
1384 				fio.old_blkaddr, fio.old_blkaddr);
1385 	f2fs_invalidate_compress_page(fio.sbi, fio.old_blkaddr);
1386 
1387 	set_page_dirty(fio.encrypted_page);
1388 	if (clear_page_dirty_for_io(fio.encrypted_page))
1389 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
1390 
1391 	set_page_writeback(fio.encrypted_page);
1392 
1393 	fio.op = REQ_OP_WRITE;
1394 	fio.op_flags = REQ_SYNC;
1395 	fio.new_blkaddr = newaddr;
1396 	f2fs_submit_page_write(&fio);
1397 	if (fio.retry) {
1398 		err = -EAGAIN;
1399 		if (PageWriteback(fio.encrypted_page))
1400 			end_page_writeback(fio.encrypted_page);
1401 		goto put_page_out;
1402 	}
1403 
1404 	f2fs_update_iostat(fio.sbi, NULL, FS_GC_DATA_IO, F2FS_BLKSIZE);
1405 
1406 	f2fs_update_data_blkaddr(&dn, newaddr);
1407 	set_inode_flag(inode, FI_APPEND_WRITE);
1408 	if (page->index == 0)
1409 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
1410 put_page_out:
1411 	f2fs_put_page(fio.encrypted_page, 1);
1412 recover_block:
1413 	if (err)
1414 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
1415 							true, true, true);
1416 up_out:
1417 	if (lfs_mode)
1418 		f2fs_up_write(&fio.sbi->io_order_lock);
1419 put_out:
1420 	f2fs_put_dnode(&dn);
1421 out:
1422 	f2fs_put_page(page, 1);
1423 	return err;
1424 }
1425 
1426 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
1427 							unsigned int segno, int off)
1428 {
1429 	struct page *page;
1430 	int err = 0;
1431 
1432 	page = f2fs_get_lock_data_page(inode, bidx, true);
1433 	if (IS_ERR(page))
1434 		return PTR_ERR(page);
1435 
1436 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1437 		err = -ENOENT;
1438 		goto out;
1439 	}
1440 
1441 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1442 	if (err)
1443 		goto out;
1444 
1445 	if (gc_type == BG_GC) {
1446 		if (PageWriteback(page)) {
1447 			err = -EAGAIN;
1448 			goto out;
1449 		}
1450 		set_page_dirty(page);
1451 		set_page_private_gcing(page);
1452 	} else {
1453 		struct f2fs_io_info fio = {
1454 			.sbi = F2FS_I_SB(inode),
1455 			.ino = inode->i_ino,
1456 			.type = DATA,
1457 			.temp = COLD,
1458 			.op = REQ_OP_WRITE,
1459 			.op_flags = REQ_SYNC,
1460 			.old_blkaddr = NULL_ADDR,
1461 			.page = page,
1462 			.encrypted_page = NULL,
1463 			.need_lock = LOCK_REQ,
1464 			.io_type = FS_GC_DATA_IO,
1465 		};
1466 		bool is_dirty = PageDirty(page);
1467 
1468 retry:
1469 		f2fs_wait_on_page_writeback(page, DATA, true, true);
1470 
1471 		set_page_dirty(page);
1472 		if (clear_page_dirty_for_io(page)) {
1473 			inode_dec_dirty_pages(inode);
1474 			f2fs_remove_dirty_inode(inode);
1475 		}
1476 
1477 		set_page_private_gcing(page);
1478 
1479 		err = f2fs_do_write_data_page(&fio);
1480 		if (err) {
1481 			clear_page_private_gcing(page);
1482 			if (err == -ENOMEM) {
1483 				memalloc_retry_wait(GFP_NOFS);
1484 				goto retry;
1485 			}
1486 			if (is_dirty)
1487 				set_page_dirty(page);
1488 		}
1489 	}
1490 out:
1491 	f2fs_put_page(page, 1);
1492 	return err;
1493 }
1494 
1495 /*
1496  * This function tries to get parent node of victim data block, and identifies
1497  * data block validity. If the block is valid, copy that with cold status and
1498  * modify parent node.
1499  * If the parent node is not valid or the data block address is different,
1500  * the victim data block is ignored.
1501  */
1502 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1503 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
1504 		bool force_migrate)
1505 {
1506 	struct super_block *sb = sbi->sb;
1507 	struct f2fs_summary *entry;
1508 	block_t start_addr;
1509 	int off;
1510 	int phase = 0;
1511 	int submitted = 0;
1512 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1513 
1514 	start_addr = START_BLOCK(sbi, segno);
1515 
1516 next_step:
1517 	entry = sum;
1518 
1519 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1520 		struct page *data_page;
1521 		struct inode *inode;
1522 		struct node_info dni; /* dnode info for the data */
1523 		unsigned int ofs_in_node, nofs;
1524 		block_t start_bidx;
1525 		nid_t nid = le32_to_cpu(entry->nid);
1526 
1527 		/*
1528 		 * stop BG_GC if there is not enough free sections.
1529 		 * Or, stop GC if the segment becomes fully valid caused by
1530 		 * race condition along with SSR block allocation.
1531 		 */
1532 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1533 			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
1534 							CAP_BLKS_PER_SEC(sbi)))
1535 			return submitted;
1536 
1537 		if (check_valid_map(sbi, segno, off) == 0)
1538 			continue;
1539 
1540 		if (phase == 0) {
1541 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1542 							META_NAT, true);
1543 			continue;
1544 		}
1545 
1546 		if (phase == 1) {
1547 			f2fs_ra_node_page(sbi, nid);
1548 			continue;
1549 		}
1550 
1551 		/* Get an inode by ino with checking validity */
1552 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1553 			continue;
1554 
1555 		if (phase == 2) {
1556 			f2fs_ra_node_page(sbi, dni.ino);
1557 			continue;
1558 		}
1559 
1560 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1561 
1562 		if (phase == 3) {
1563 			int err;
1564 
1565 			inode = f2fs_iget(sb, dni.ino);
1566 			if (IS_ERR(inode) || is_bad_inode(inode) ||
1567 					special_file(inode->i_mode))
1568 				continue;
1569 
1570 			err = f2fs_gc_pinned_control(inode, gc_type, segno);
1571 			if (err == -EAGAIN) {
1572 				iput(inode);
1573 				return submitted;
1574 			}
1575 
1576 			if (!f2fs_down_write_trylock(
1577 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1578 				iput(inode);
1579 				sbi->skipped_gc_rwsem++;
1580 				continue;
1581 			}
1582 
1583 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1584 								ofs_in_node;
1585 
1586 			if (f2fs_post_read_required(inode)) {
1587 				int err = ra_data_block(inode, start_bidx);
1588 
1589 				f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1590 				if (err) {
1591 					iput(inode);
1592 					continue;
1593 				}
1594 				add_gc_inode(gc_list, inode);
1595 				continue;
1596 			}
1597 
1598 			data_page = f2fs_get_read_data_page(inode, start_bidx,
1599 							REQ_RAHEAD, true, NULL);
1600 			f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1601 			if (IS_ERR(data_page)) {
1602 				iput(inode);
1603 				continue;
1604 			}
1605 
1606 			f2fs_put_page(data_page, 0);
1607 			add_gc_inode(gc_list, inode);
1608 			continue;
1609 		}
1610 
1611 		/* phase 4 */
1612 		inode = find_gc_inode(gc_list, dni.ino);
1613 		if (inode) {
1614 			struct f2fs_inode_info *fi = F2FS_I(inode);
1615 			bool locked = false;
1616 			int err;
1617 
1618 			if (S_ISREG(inode->i_mode)) {
1619 				if (!f2fs_down_write_trylock(&fi->i_gc_rwsem[WRITE])) {
1620 					sbi->skipped_gc_rwsem++;
1621 					continue;
1622 				}
1623 				if (!f2fs_down_write_trylock(
1624 						&fi->i_gc_rwsem[READ])) {
1625 					sbi->skipped_gc_rwsem++;
1626 					f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
1627 					continue;
1628 				}
1629 				locked = true;
1630 
1631 				/* wait for all inflight aio data */
1632 				inode_dio_wait(inode);
1633 			}
1634 
1635 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1636 								+ ofs_in_node;
1637 			if (f2fs_post_read_required(inode))
1638 				err = move_data_block(inode, start_bidx,
1639 							gc_type, segno, off);
1640 			else
1641 				err = move_data_page(inode, start_bidx, gc_type,
1642 								segno, off);
1643 
1644 			if (!err && (gc_type == FG_GC ||
1645 					f2fs_post_read_required(inode)))
1646 				submitted++;
1647 
1648 			if (locked) {
1649 				f2fs_up_write(&fi->i_gc_rwsem[READ]);
1650 				f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
1651 			}
1652 
1653 			stat_inc_data_blk_count(sbi, 1, gc_type);
1654 		}
1655 	}
1656 
1657 	if (++phase < 5)
1658 		goto next_step;
1659 
1660 	return submitted;
1661 }
1662 
1663 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1664 			int gc_type)
1665 {
1666 	struct sit_info *sit_i = SIT_I(sbi);
1667 	int ret;
1668 
1669 	down_write(&sit_i->sentry_lock);
1670 	ret = f2fs_get_victim(sbi, victim, gc_type, NO_CHECK_TYPE, LFS, 0);
1671 	up_write(&sit_i->sentry_lock);
1672 	return ret;
1673 }
1674 
1675 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1676 				unsigned int start_segno,
1677 				struct gc_inode_list *gc_list, int gc_type,
1678 				bool force_migrate)
1679 {
1680 	struct page *sum_page;
1681 	struct f2fs_summary_block *sum;
1682 	struct blk_plug plug;
1683 	unsigned int segno = start_segno;
1684 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1685 	int seg_freed = 0, migrated = 0;
1686 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1687 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1688 	int submitted = 0;
1689 
1690 	if (__is_large_section(sbi))
1691 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1692 
1693 	/*
1694 	 * zone-capacity can be less than zone-size in zoned devices,
1695 	 * resulting in less than expected usable segments in the zone,
1696 	 * calculate the end segno in the zone which can be garbage collected
1697 	 */
1698 	if (f2fs_sb_has_blkzoned(sbi))
1699 		end_segno -= sbi->segs_per_sec -
1700 					f2fs_usable_segs_in_sec(sbi, segno);
1701 
1702 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
1703 
1704 	/* readahead multi ssa blocks those have contiguous address */
1705 	if (__is_large_section(sbi))
1706 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1707 					end_segno - segno, META_SSA, true);
1708 
1709 	/* reference all summary page */
1710 	while (segno < end_segno) {
1711 		sum_page = f2fs_get_sum_page(sbi, segno++);
1712 		if (IS_ERR(sum_page)) {
1713 			int err = PTR_ERR(sum_page);
1714 
1715 			end_segno = segno - 1;
1716 			for (segno = start_segno; segno < end_segno; segno++) {
1717 				sum_page = find_get_page(META_MAPPING(sbi),
1718 						GET_SUM_BLOCK(sbi, segno));
1719 				f2fs_put_page(sum_page, 0);
1720 				f2fs_put_page(sum_page, 0);
1721 			}
1722 			return err;
1723 		}
1724 		unlock_page(sum_page);
1725 	}
1726 
1727 	blk_start_plug(&plug);
1728 
1729 	for (segno = start_segno; segno < end_segno; segno++) {
1730 
1731 		/* find segment summary of victim */
1732 		sum_page = find_get_page(META_MAPPING(sbi),
1733 					GET_SUM_BLOCK(sbi, segno));
1734 		f2fs_put_page(sum_page, 0);
1735 
1736 		if (get_valid_blocks(sbi, segno, false) == 0)
1737 			goto freed;
1738 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1739 				migrated >= sbi->migration_granularity)
1740 			goto skip;
1741 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1742 			goto skip;
1743 
1744 		sum = page_address(sum_page);
1745 		if (type != GET_SUM_TYPE((&sum->footer))) {
1746 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1747 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1748 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1749 			f2fs_stop_checkpoint(sbi, false,
1750 				STOP_CP_REASON_CORRUPTED_SUMMARY);
1751 			goto skip;
1752 		}
1753 
1754 		/*
1755 		 * this is to avoid deadlock:
1756 		 * - lock_page(sum_page)         - f2fs_replace_block
1757 		 *  - check_valid_map()            - down_write(sentry_lock)
1758 		 *   - down_read(sentry_lock)     - change_curseg()
1759 		 *                                  - lock_page(sum_page)
1760 		 */
1761 		if (type == SUM_TYPE_NODE)
1762 			submitted += gc_node_segment(sbi, sum->entries, segno,
1763 								gc_type);
1764 		else
1765 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1766 							segno, gc_type,
1767 							force_migrate);
1768 
1769 		stat_inc_seg_count(sbi, type, gc_type);
1770 		sbi->gc_reclaimed_segs[sbi->gc_mode]++;
1771 		migrated++;
1772 
1773 freed:
1774 		if (gc_type == FG_GC &&
1775 				get_valid_blocks(sbi, segno, false) == 0)
1776 			seg_freed++;
1777 
1778 		if (__is_large_section(sbi))
1779 			sbi->next_victim_seg[gc_type] =
1780 				(segno + 1 < end_segno) ? segno + 1 : NULL_SEGNO;
1781 skip:
1782 		f2fs_put_page(sum_page, 0);
1783 	}
1784 
1785 	if (submitted)
1786 		f2fs_submit_merged_write(sbi,
1787 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1788 
1789 	blk_finish_plug(&plug);
1790 
1791 	stat_inc_call_count(sbi->stat_info);
1792 
1793 	return seg_freed;
1794 }
1795 
1796 int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
1797 {
1798 	int gc_type = gc_control->init_gc_type;
1799 	unsigned int segno = gc_control->victim_segno;
1800 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1801 	int ret = 0;
1802 	struct cp_control cpc;
1803 	struct gc_inode_list gc_list = {
1804 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1805 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1806 	};
1807 	unsigned int skipped_round = 0, round = 0;
1808 	unsigned int upper_secs;
1809 
1810 	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
1811 				gc_control->nr_free_secs,
1812 				get_pages(sbi, F2FS_DIRTY_NODES),
1813 				get_pages(sbi, F2FS_DIRTY_DENTS),
1814 				get_pages(sbi, F2FS_DIRTY_IMETA),
1815 				free_sections(sbi),
1816 				free_segments(sbi),
1817 				reserved_segments(sbi),
1818 				prefree_segments(sbi));
1819 
1820 	cpc.reason = __get_cp_reason(sbi);
1821 gc_more:
1822 	sbi->skipped_gc_rwsem = 0;
1823 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1824 		ret = -EINVAL;
1825 		goto stop;
1826 	}
1827 	if (unlikely(f2fs_cp_error(sbi))) {
1828 		ret = -EIO;
1829 		goto stop;
1830 	}
1831 
1832 	/* Let's run FG_GC, if we don't have enough space. */
1833 	if (has_not_enough_free_secs(sbi, 0, 0)) {
1834 		gc_type = FG_GC;
1835 
1836 		/*
1837 		 * For example, if there are many prefree_segments below given
1838 		 * threshold, we can make them free by checkpoint. Then, we
1839 		 * secure free segments which doesn't need fggc any more.
1840 		 */
1841 		if (prefree_segments(sbi)) {
1842 			ret = f2fs_write_checkpoint(sbi, &cpc);
1843 			if (ret)
1844 				goto stop;
1845 		}
1846 	}
1847 
1848 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1849 	if (gc_type == BG_GC && gc_control->no_bg_gc) {
1850 		ret = -EINVAL;
1851 		goto stop;
1852 	}
1853 retry:
1854 	ret = __get_victim(sbi, &segno, gc_type);
1855 	if (ret) {
1856 		/* allow to search victim from sections has pinned data */
1857 		if (ret == -ENODATA && gc_type == FG_GC &&
1858 				f2fs_pinned_section_exists(DIRTY_I(sbi))) {
1859 			f2fs_unpin_all_sections(sbi, false);
1860 			goto retry;
1861 		}
1862 		goto stop;
1863 	}
1864 
1865 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type,
1866 				gc_control->should_migrate_blocks);
1867 	total_freed += seg_freed;
1868 
1869 	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
1870 		sec_freed++;
1871 
1872 	if (gc_type == FG_GC) {
1873 		sbi->cur_victim_sec = NULL_SEGNO;
1874 
1875 		if (has_enough_free_secs(sbi, sec_freed, 0)) {
1876 			if (!gc_control->no_bg_gc &&
1877 			    sec_freed < gc_control->nr_free_secs)
1878 				goto go_gc_more;
1879 			goto stop;
1880 		}
1881 		if (sbi->skipped_gc_rwsem)
1882 			skipped_round++;
1883 		round++;
1884 		if (skipped_round > MAX_SKIP_GC_COUNT &&
1885 				skipped_round * 2 >= round) {
1886 			ret = f2fs_write_checkpoint(sbi, &cpc);
1887 			goto stop;
1888 		}
1889 	} else if (has_enough_free_secs(sbi, 0, 0)) {
1890 		goto stop;
1891 	}
1892 
1893 	__get_secs_required(sbi, NULL, &upper_secs, NULL);
1894 
1895 	/*
1896 	 * Write checkpoint to reclaim prefree segments.
1897 	 * We need more three extra sections for writer's data/node/dentry.
1898 	 */
1899 	if (free_sections(sbi) <= upper_secs + NR_GC_CHECKPOINT_SECS &&
1900 				prefree_segments(sbi)) {
1901 		ret = f2fs_write_checkpoint(sbi, &cpc);
1902 		if (ret)
1903 			goto stop;
1904 	}
1905 go_gc_more:
1906 	segno = NULL_SEGNO;
1907 	goto gc_more;
1908 
1909 stop:
1910 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1911 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = gc_control->victim_segno;
1912 
1913 	if (gc_type == FG_GC)
1914 		f2fs_unpin_all_sections(sbi, true);
1915 
1916 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1917 				get_pages(sbi, F2FS_DIRTY_NODES),
1918 				get_pages(sbi, F2FS_DIRTY_DENTS),
1919 				get_pages(sbi, F2FS_DIRTY_IMETA),
1920 				free_sections(sbi),
1921 				free_segments(sbi),
1922 				reserved_segments(sbi),
1923 				prefree_segments(sbi));
1924 
1925 	f2fs_up_write(&sbi->gc_lock);
1926 
1927 	put_gc_inode(&gc_list);
1928 
1929 	if (gc_control->err_gc_skipped && !ret)
1930 		ret = sec_freed ? 0 : -EAGAIN;
1931 	return ret;
1932 }
1933 
1934 int __init f2fs_create_garbage_collection_cache(void)
1935 {
1936 	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
1937 					sizeof(struct victim_entry));
1938 	return victim_entry_slab ? 0 : -ENOMEM;
1939 }
1940 
1941 void f2fs_destroy_garbage_collection_cache(void)
1942 {
1943 	kmem_cache_destroy(victim_entry_slab);
1944 }
1945 
1946 static void init_atgc_management(struct f2fs_sb_info *sbi)
1947 {
1948 	struct atgc_management *am = &sbi->am;
1949 
1950 	if (test_opt(sbi, ATGC) &&
1951 		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
1952 		am->atgc_enabled = true;
1953 
1954 	am->root = RB_ROOT_CACHED;
1955 	INIT_LIST_HEAD(&am->victim_list);
1956 	am->victim_count = 0;
1957 
1958 	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
1959 	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
1960 	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
1961 	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
1962 }
1963 
1964 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1965 {
1966 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1967 
1968 	/* give warm/cold data area from slower device */
1969 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1970 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1971 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1972 
1973 	init_atgc_management(sbi);
1974 }
1975 
1976 static int free_segment_range(struct f2fs_sb_info *sbi,
1977 				unsigned int secs, bool gc_only)
1978 {
1979 	unsigned int segno, next_inuse, start, end;
1980 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1981 	int gc_mode, gc_type;
1982 	int err = 0;
1983 	int type;
1984 
1985 	/* Force block allocation for GC */
1986 	MAIN_SECS(sbi) -= secs;
1987 	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
1988 	end = MAIN_SEGS(sbi) - 1;
1989 
1990 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1991 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1992 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
1993 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1994 
1995 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1996 		if (sbi->next_victim_seg[gc_type] >= start)
1997 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1998 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1999 
2000 	/* Move out cursegs from the target range */
2001 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++)
2002 		f2fs_allocate_segment_for_resize(sbi, type, start, end);
2003 
2004 	/* do GC to move out valid blocks in the range */
2005 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
2006 		struct gc_inode_list gc_list = {
2007 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
2008 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
2009 		};
2010 
2011 		do_garbage_collect(sbi, segno, &gc_list, FG_GC, true);
2012 		put_gc_inode(&gc_list);
2013 
2014 		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
2015 			err = -EAGAIN;
2016 			goto out;
2017 		}
2018 		if (fatal_signal_pending(current)) {
2019 			err = -ERESTARTSYS;
2020 			goto out;
2021 		}
2022 	}
2023 	if (gc_only)
2024 		goto out;
2025 
2026 	err = f2fs_write_checkpoint(sbi, &cpc);
2027 	if (err)
2028 		goto out;
2029 
2030 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
2031 	if (next_inuse <= end) {
2032 		f2fs_err(sbi, "segno %u should be free but still inuse!",
2033 			 next_inuse);
2034 		f2fs_bug_on(sbi, 1);
2035 	}
2036 out:
2037 	MAIN_SECS(sbi) += secs;
2038 	return err;
2039 }
2040 
2041 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
2042 {
2043 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
2044 	int section_count;
2045 	int segment_count;
2046 	int segment_count_main;
2047 	long long block_count;
2048 	int segs = secs * sbi->segs_per_sec;
2049 
2050 	f2fs_down_write(&sbi->sb_lock);
2051 
2052 	section_count = le32_to_cpu(raw_sb->section_count);
2053 	segment_count = le32_to_cpu(raw_sb->segment_count);
2054 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
2055 	block_count = le64_to_cpu(raw_sb->block_count);
2056 
2057 	raw_sb->section_count = cpu_to_le32(section_count + secs);
2058 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
2059 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
2060 	raw_sb->block_count = cpu_to_le64(block_count +
2061 					(long long)segs * sbi->blocks_per_seg);
2062 	if (f2fs_is_multi_device(sbi)) {
2063 		int last_dev = sbi->s_ndevs - 1;
2064 		int dev_segs =
2065 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
2066 
2067 		raw_sb->devs[last_dev].total_segments =
2068 						cpu_to_le32(dev_segs + segs);
2069 	}
2070 
2071 	f2fs_up_write(&sbi->sb_lock);
2072 }
2073 
2074 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
2075 {
2076 	int segs = secs * sbi->segs_per_sec;
2077 	long long blks = (long long)segs * sbi->blocks_per_seg;
2078 	long long user_block_count =
2079 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
2080 
2081 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
2082 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
2083 	MAIN_SECS(sbi) += secs;
2084 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
2085 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
2086 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
2087 
2088 	if (f2fs_is_multi_device(sbi)) {
2089 		int last_dev = sbi->s_ndevs - 1;
2090 
2091 		FDEV(last_dev).total_segments =
2092 				(int)FDEV(last_dev).total_segments + segs;
2093 		FDEV(last_dev).end_blk =
2094 				(long long)FDEV(last_dev).end_blk + blks;
2095 #ifdef CONFIG_BLK_DEV_ZONED
2096 		FDEV(last_dev).nr_blkz = FDEV(last_dev).nr_blkz +
2097 					div_u64(blks, sbi->blocks_per_blkz);
2098 #endif
2099 	}
2100 }
2101 
2102 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
2103 {
2104 	__u64 old_block_count, shrunk_blocks;
2105 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
2106 	unsigned int secs;
2107 	int err = 0;
2108 	__u32 rem;
2109 
2110 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
2111 	if (block_count > old_block_count)
2112 		return -EINVAL;
2113 
2114 	if (f2fs_is_multi_device(sbi)) {
2115 		int last_dev = sbi->s_ndevs - 1;
2116 		__u64 last_segs = FDEV(last_dev).total_segments;
2117 
2118 		if (block_count + last_segs * sbi->blocks_per_seg <=
2119 								old_block_count)
2120 			return -EINVAL;
2121 	}
2122 
2123 	/* new fs size should align to section size */
2124 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
2125 	if (rem)
2126 		return -EINVAL;
2127 
2128 	if (block_count == old_block_count)
2129 		return 0;
2130 
2131 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
2132 		f2fs_err(sbi, "Should run fsck to repair first.");
2133 		return -EFSCORRUPTED;
2134 	}
2135 
2136 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
2137 		f2fs_err(sbi, "Checkpoint should be enabled.");
2138 		return -EINVAL;
2139 	}
2140 
2141 	shrunk_blocks = old_block_count - block_count;
2142 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
2143 
2144 	/* stop other GC */
2145 	if (!f2fs_down_write_trylock(&sbi->gc_lock))
2146 		return -EAGAIN;
2147 
2148 	/* stop CP to protect MAIN_SEC in free_segment_range */
2149 	f2fs_lock_op(sbi);
2150 
2151 	spin_lock(&sbi->stat_lock);
2152 	if (shrunk_blocks + valid_user_blocks(sbi) +
2153 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2154 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2155 		err = -ENOSPC;
2156 	spin_unlock(&sbi->stat_lock);
2157 
2158 	if (err)
2159 		goto out_unlock;
2160 
2161 	err = free_segment_range(sbi, secs, true);
2162 
2163 out_unlock:
2164 	f2fs_unlock_op(sbi);
2165 	f2fs_up_write(&sbi->gc_lock);
2166 	if (err)
2167 		return err;
2168 
2169 	freeze_super(sbi->sb);
2170 	f2fs_down_write(&sbi->gc_lock);
2171 	f2fs_down_write(&sbi->cp_global_sem);
2172 
2173 	spin_lock(&sbi->stat_lock);
2174 	if (shrunk_blocks + valid_user_blocks(sbi) +
2175 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2176 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2177 		err = -ENOSPC;
2178 	else
2179 		sbi->user_block_count -= shrunk_blocks;
2180 	spin_unlock(&sbi->stat_lock);
2181 	if (err)
2182 		goto out_err;
2183 
2184 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
2185 	err = free_segment_range(sbi, secs, false);
2186 	if (err)
2187 		goto recover_out;
2188 
2189 	update_sb_metadata(sbi, -secs);
2190 
2191 	err = f2fs_commit_super(sbi, false);
2192 	if (err) {
2193 		update_sb_metadata(sbi, secs);
2194 		goto recover_out;
2195 	}
2196 
2197 	update_fs_metadata(sbi, -secs);
2198 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2199 	set_sbi_flag(sbi, SBI_IS_DIRTY);
2200 
2201 	err = f2fs_write_checkpoint(sbi, &cpc);
2202 	if (err) {
2203 		update_fs_metadata(sbi, secs);
2204 		update_sb_metadata(sbi, secs);
2205 		f2fs_commit_super(sbi, false);
2206 	}
2207 recover_out:
2208 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2209 	if (err) {
2210 		set_sbi_flag(sbi, SBI_NEED_FSCK);
2211 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
2212 
2213 		spin_lock(&sbi->stat_lock);
2214 		sbi->user_block_count += shrunk_blocks;
2215 		spin_unlock(&sbi->stat_lock);
2216 	}
2217 out_err:
2218 	f2fs_up_write(&sbi->cp_global_sem);
2219 	f2fs_up_write(&sbi->gc_lock);
2220 	thaw_super(sbi->sb);
2221 	return err;
2222 }
2223