xref: /linux/fs/f2fs/gc.c (revision ab52c59103002b49f2455371e4b9c56ba3ef1781)
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_freezable_timeout(*wq,
50 				kthread_should_stop() ||
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 (f2fs_readonly(sbi->sb)) {
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 		stat_inc_gc_call_count(sbi, foreground ?
125 					FOREGROUND : BACKGROUND);
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 = SEGS_PER_SEC(sbi);
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. */
284 	if (f2fs_need_rand_seg(sbi))
285 		p->offset = get_random_u32_below(MAIN_SECS(sbi) *
286 						SEGS_PER_SEC(sbi));
287 	else if (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 BLKS_PER_SEG(sbi);
299 	else if (p->alloc_mode == AT_SSR)
300 		return UINT_MAX;
301 
302 	/* LFS */
303 	if (p->gc_mode == GC_GREEDY)
304 		return SEGS_TO_BLKS(sbi, 2 * 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 = BLKS_TO_SEGS(sbi, vblocks * 100);
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 < SEGS_PER_SEC(sbi); i++)
500 		mtime += get_seg_entry(sbi, start + i)->mtime;
501 	mtime = div_u64(mtime, SEGS_PER_SEC(sbi));
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 vblocks;
603 	unsigned int dirty_threshold = max(am->max_candidate_count,
604 					am->candidate_ratio *
605 					am->victim_count / 100);
606 	unsigned int cost, iter;
607 	int stage = 0;
608 
609 	if (max_mtime < min_mtime)
610 		return;
611 	max_mtime += 1;
612 next_stage:
613 	iter = 0;
614 	ve = __lookup_victim_entry(sbi, p->age);
615 next_node:
616 	if (!ve) {
617 		if (stage++ == 0)
618 			goto next_stage;
619 		return;
620 	}
621 
622 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
623 		goto skip_node;
624 
625 	age = max_mtime - ve->mtime;
626 
627 	vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
628 	f2fs_bug_on(sbi, !vblocks);
629 
630 	/* rare case */
631 	if (vblocks == BLKS_PER_SEG(sbi))
632 		goto skip_node;
633 
634 	iter++;
635 
636 	age = max_mtime - abs(p->age - age);
637 	cost = UINT_MAX - vblocks;
638 
639 	if (cost < p->min_cost ||
640 			(cost == p->min_cost && age > p->oldest_age)) {
641 		p->min_cost = cost;
642 		p->oldest_age = age;
643 		p->min_segno = ve->segno;
644 	}
645 skip_node:
646 	if (iter < dirty_threshold) {
647 		ve = rb_entry(stage == 0 ? rb_prev(&ve->rb_node) :
648 					rb_next(&ve->rb_node),
649 					struct victim_entry, rb_node);
650 		goto next_node;
651 	}
652 
653 	if (stage++ == 0)
654 		goto next_stage;
655 }
656 
657 static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
658 						struct victim_sel_policy *p)
659 {
660 	f2fs_bug_on(sbi, !f2fs_check_victim_tree(sbi, &sbi->am.root));
661 
662 	if (p->gc_mode == GC_AT)
663 		atgc_lookup_victim(sbi, p);
664 	else if (p->alloc_mode == AT_SSR)
665 		atssr_lookup_victim(sbi, p);
666 	else
667 		f2fs_bug_on(sbi, 1);
668 }
669 
670 static void release_victim_entry(struct f2fs_sb_info *sbi)
671 {
672 	struct atgc_management *am = &sbi->am;
673 	struct victim_entry *ve, *tmp;
674 
675 	list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
676 		list_del(&ve->list);
677 		kmem_cache_free(victim_entry_slab, ve);
678 		am->victim_count--;
679 	}
680 
681 	am->root = RB_ROOT_CACHED;
682 
683 	f2fs_bug_on(sbi, am->victim_count);
684 	f2fs_bug_on(sbi, !list_empty(&am->victim_list));
685 }
686 
687 static bool f2fs_pin_section(struct f2fs_sb_info *sbi, unsigned int segno)
688 {
689 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
690 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
691 
692 	if (!dirty_i->enable_pin_section)
693 		return false;
694 	if (!test_and_set_bit(secno, dirty_i->pinned_secmap))
695 		dirty_i->pinned_secmap_cnt++;
696 	return true;
697 }
698 
699 static bool f2fs_pinned_section_exists(struct dirty_seglist_info *dirty_i)
700 {
701 	return dirty_i->pinned_secmap_cnt;
702 }
703 
704 static bool f2fs_section_is_pinned(struct dirty_seglist_info *dirty_i,
705 						unsigned int secno)
706 {
707 	return dirty_i->enable_pin_section &&
708 		f2fs_pinned_section_exists(dirty_i) &&
709 		test_bit(secno, dirty_i->pinned_secmap);
710 }
711 
712 static void f2fs_unpin_all_sections(struct f2fs_sb_info *sbi, bool enable)
713 {
714 	unsigned int bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
715 
716 	if (f2fs_pinned_section_exists(DIRTY_I(sbi))) {
717 		memset(DIRTY_I(sbi)->pinned_secmap, 0, bitmap_size);
718 		DIRTY_I(sbi)->pinned_secmap_cnt = 0;
719 	}
720 	DIRTY_I(sbi)->enable_pin_section = enable;
721 }
722 
723 static int f2fs_gc_pinned_control(struct inode *inode, int gc_type,
724 							unsigned int segno)
725 {
726 	if (!f2fs_is_pinned_file(inode))
727 		return 0;
728 	if (gc_type != FG_GC)
729 		return -EBUSY;
730 	if (!f2fs_pin_section(F2FS_I_SB(inode), segno))
731 		f2fs_pin_file_control(inode, true);
732 	return -EAGAIN;
733 }
734 
735 /*
736  * This function is called from two paths.
737  * One is garbage collection and the other is SSR segment selection.
738  * When it is called during GC, it just gets a victim segment
739  * and it does not remove it from dirty seglist.
740  * When it is called from SSR segment selection, it finds a segment
741  * which has minimum valid blocks and removes it from dirty seglist.
742  */
743 int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,
744 			int gc_type, int type, char alloc_mode,
745 			unsigned long long age)
746 {
747 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
748 	struct sit_info *sm = SIT_I(sbi);
749 	struct victim_sel_policy p;
750 	unsigned int secno, last_victim;
751 	unsigned int last_segment;
752 	unsigned int nsearched;
753 	bool is_atgc;
754 	int ret = 0;
755 
756 	mutex_lock(&dirty_i->seglist_lock);
757 	last_segment = MAIN_SECS(sbi) * SEGS_PER_SEC(sbi);
758 
759 	p.alloc_mode = alloc_mode;
760 	p.age = age;
761 	p.age_threshold = sbi->am.age_threshold;
762 
763 retry:
764 	select_policy(sbi, gc_type, type, &p);
765 	p.min_segno = NULL_SEGNO;
766 	p.oldest_age = 0;
767 	p.min_cost = get_max_cost(sbi, &p);
768 
769 	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
770 	nsearched = 0;
771 
772 	if (is_atgc)
773 		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
774 
775 	if (*result != NULL_SEGNO) {
776 		if (!get_valid_blocks(sbi, *result, false)) {
777 			ret = -ENODATA;
778 			goto out;
779 		}
780 
781 		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
782 			ret = -EBUSY;
783 		else
784 			p.min_segno = *result;
785 		goto out;
786 	}
787 
788 	ret = -ENODATA;
789 	if (p.max_search == 0)
790 		goto out;
791 
792 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
793 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
794 			p.min_segno = sbi->next_victim_seg[BG_GC];
795 			*result = p.min_segno;
796 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
797 			goto got_result;
798 		}
799 		if (gc_type == FG_GC &&
800 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
801 			p.min_segno = sbi->next_victim_seg[FG_GC];
802 			*result = p.min_segno;
803 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
804 			goto got_result;
805 		}
806 	}
807 
808 	last_victim = sm->last_victim[p.gc_mode];
809 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
810 		p.min_segno = check_bg_victims(sbi);
811 		if (p.min_segno != NULL_SEGNO)
812 			goto got_it;
813 	}
814 
815 	while (1) {
816 		unsigned long cost, *dirty_bitmap;
817 		unsigned int unit_no, segno;
818 
819 		dirty_bitmap = p.dirty_bitmap;
820 		unit_no = find_next_bit(dirty_bitmap,
821 				last_segment / p.ofs_unit,
822 				p.offset / p.ofs_unit);
823 		segno = unit_no * p.ofs_unit;
824 		if (segno >= last_segment) {
825 			if (sm->last_victim[p.gc_mode]) {
826 				last_segment =
827 					sm->last_victim[p.gc_mode];
828 				sm->last_victim[p.gc_mode] = 0;
829 				p.offset = 0;
830 				continue;
831 			}
832 			break;
833 		}
834 
835 		p.offset = segno + p.ofs_unit;
836 		nsearched++;
837 
838 #ifdef CONFIG_F2FS_CHECK_FS
839 		/*
840 		 * skip selecting the invalid segno (that is failed due to block
841 		 * validity check failure during GC) to avoid endless GC loop in
842 		 * such cases.
843 		 */
844 		if (test_bit(segno, sm->invalid_segmap))
845 			goto next;
846 #endif
847 
848 		secno = GET_SEC_FROM_SEG(sbi, segno);
849 
850 		if (sec_usage_check(sbi, secno))
851 			goto next;
852 
853 		/* Don't touch checkpointed data */
854 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
855 			if (p.alloc_mode == LFS) {
856 				/*
857 				 * LFS is set to find source section during GC.
858 				 * The victim should have no checkpointed data.
859 				 */
860 				if (get_ckpt_valid_blocks(sbi, segno, true))
861 					goto next;
862 			} else {
863 				/*
864 				 * SSR | AT_SSR are set to find target segment
865 				 * for writes which can be full by checkpointed
866 				 * and newly written blocks.
867 				 */
868 				if (!f2fs_segment_has_free_slot(sbi, segno))
869 					goto next;
870 			}
871 		}
872 
873 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
874 			goto next;
875 
876 		if (gc_type == FG_GC && f2fs_section_is_pinned(dirty_i, secno))
877 			goto next;
878 
879 		if (is_atgc) {
880 			add_victim_entry(sbi, &p, segno);
881 			goto next;
882 		}
883 
884 		cost = get_gc_cost(sbi, segno, &p);
885 
886 		if (p.min_cost > cost) {
887 			p.min_segno = segno;
888 			p.min_cost = cost;
889 		}
890 next:
891 		if (nsearched >= p.max_search) {
892 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
893 				sm->last_victim[p.gc_mode] =
894 					last_victim + p.ofs_unit;
895 			else
896 				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
897 			sm->last_victim[p.gc_mode] %=
898 				(MAIN_SECS(sbi) * SEGS_PER_SEC(sbi));
899 			break;
900 		}
901 	}
902 
903 	/* get victim for GC_AT/AT_SSR */
904 	if (is_atgc) {
905 		lookup_victim_by_age(sbi, &p);
906 		release_victim_entry(sbi);
907 	}
908 
909 	if (is_atgc && p.min_segno == NULL_SEGNO &&
910 			sm->elapsed_time < p.age_threshold) {
911 		p.age_threshold = 0;
912 		goto retry;
913 	}
914 
915 	if (p.min_segno != NULL_SEGNO) {
916 got_it:
917 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
918 got_result:
919 		if (p.alloc_mode == LFS) {
920 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
921 			if (gc_type == FG_GC)
922 				sbi->cur_victim_sec = secno;
923 			else
924 				set_bit(secno, dirty_i->victim_secmap);
925 		}
926 		ret = 0;
927 
928 	}
929 out:
930 	if (p.min_segno != NULL_SEGNO)
931 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
932 				sbi->cur_victim_sec,
933 				prefree_segments(sbi), free_segments(sbi));
934 	mutex_unlock(&dirty_i->seglist_lock);
935 
936 	return ret;
937 }
938 
939 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
940 {
941 	struct inode_entry *ie;
942 
943 	ie = radix_tree_lookup(&gc_list->iroot, ino);
944 	if (ie)
945 		return ie->inode;
946 	return NULL;
947 }
948 
949 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
950 {
951 	struct inode_entry *new_ie;
952 
953 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
954 		iput(inode);
955 		return;
956 	}
957 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab,
958 					GFP_NOFS, true, NULL);
959 	new_ie->inode = inode;
960 
961 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
962 	list_add_tail(&new_ie->list, &gc_list->ilist);
963 }
964 
965 static void put_gc_inode(struct gc_inode_list *gc_list)
966 {
967 	struct inode_entry *ie, *next_ie;
968 
969 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
970 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
971 		iput(ie->inode);
972 		list_del(&ie->list);
973 		kmem_cache_free(f2fs_inode_entry_slab, ie);
974 	}
975 }
976 
977 static int check_valid_map(struct f2fs_sb_info *sbi,
978 				unsigned int segno, int offset)
979 {
980 	struct sit_info *sit_i = SIT_I(sbi);
981 	struct seg_entry *sentry;
982 	int ret;
983 
984 	down_read(&sit_i->sentry_lock);
985 	sentry = get_seg_entry(sbi, segno);
986 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
987 	up_read(&sit_i->sentry_lock);
988 	return ret;
989 }
990 
991 /*
992  * This function compares node address got in summary with that in NAT.
993  * On validity, copy that node with cold status, otherwise (invalid node)
994  * ignore that.
995  */
996 static int gc_node_segment(struct f2fs_sb_info *sbi,
997 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
998 {
999 	struct f2fs_summary *entry;
1000 	block_t start_addr;
1001 	int off;
1002 	int phase = 0;
1003 	bool fggc = (gc_type == FG_GC);
1004 	int submitted = 0;
1005 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1006 
1007 	start_addr = START_BLOCK(sbi, segno);
1008 
1009 next_step:
1010 	entry = sum;
1011 
1012 	if (fggc && phase == 2)
1013 		atomic_inc(&sbi->wb_sync_req[NODE]);
1014 
1015 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1016 		nid_t nid = le32_to_cpu(entry->nid);
1017 		struct page *node_page;
1018 		struct node_info ni;
1019 		int err;
1020 
1021 		/* stop BG_GC if there is not enough free sections. */
1022 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
1023 			return submitted;
1024 
1025 		if (check_valid_map(sbi, segno, off) == 0)
1026 			continue;
1027 
1028 		if (phase == 0) {
1029 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1030 							META_NAT, true);
1031 			continue;
1032 		}
1033 
1034 		if (phase == 1) {
1035 			f2fs_ra_node_page(sbi, nid);
1036 			continue;
1037 		}
1038 
1039 		/* phase == 2 */
1040 		node_page = f2fs_get_node_page(sbi, nid);
1041 		if (IS_ERR(node_page))
1042 			continue;
1043 
1044 		/* block may become invalid during f2fs_get_node_page */
1045 		if (check_valid_map(sbi, segno, off) == 0) {
1046 			f2fs_put_page(node_page, 1);
1047 			continue;
1048 		}
1049 
1050 		if (f2fs_get_node_info(sbi, nid, &ni, false)) {
1051 			f2fs_put_page(node_page, 1);
1052 			continue;
1053 		}
1054 
1055 		if (ni.blk_addr != start_addr + off) {
1056 			f2fs_put_page(node_page, 1);
1057 			continue;
1058 		}
1059 
1060 		err = f2fs_move_node_page(node_page, gc_type);
1061 		if (!err && gc_type == FG_GC)
1062 			submitted++;
1063 		stat_inc_node_blk_count(sbi, 1, gc_type);
1064 	}
1065 
1066 	if (++phase < 3)
1067 		goto next_step;
1068 
1069 	if (fggc)
1070 		atomic_dec(&sbi->wb_sync_req[NODE]);
1071 	return submitted;
1072 }
1073 
1074 /*
1075  * Calculate start block index indicating the given node offset.
1076  * Be careful, caller should give this node offset only indicating direct node
1077  * blocks. If any node offsets, which point the other types of node blocks such
1078  * as indirect or double indirect node blocks, are given, it must be a caller's
1079  * bug.
1080  */
1081 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
1082 {
1083 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
1084 	unsigned int bidx;
1085 
1086 	if (node_ofs == 0)
1087 		return 0;
1088 
1089 	if (node_ofs <= 2) {
1090 		bidx = node_ofs - 1;
1091 	} else if (node_ofs <= indirect_blks) {
1092 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
1093 
1094 		bidx = node_ofs - 2 - dec;
1095 	} else {
1096 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
1097 
1098 		bidx = node_ofs - 5 - dec;
1099 	}
1100 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
1101 }
1102 
1103 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1104 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
1105 {
1106 	struct page *node_page;
1107 	nid_t nid;
1108 	unsigned int ofs_in_node, max_addrs, base;
1109 	block_t source_blkaddr;
1110 
1111 	nid = le32_to_cpu(sum->nid);
1112 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
1113 
1114 	node_page = f2fs_get_node_page(sbi, nid);
1115 	if (IS_ERR(node_page))
1116 		return false;
1117 
1118 	if (f2fs_get_node_info(sbi, nid, dni, false)) {
1119 		f2fs_put_page(node_page, 1);
1120 		return false;
1121 	}
1122 
1123 	if (sum->version != dni->version) {
1124 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
1125 			  __func__);
1126 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1127 	}
1128 
1129 	if (f2fs_check_nid_range(sbi, dni->ino)) {
1130 		f2fs_put_page(node_page, 1);
1131 		return false;
1132 	}
1133 
1134 	if (IS_INODE(node_page)) {
1135 		base = offset_in_addr(F2FS_INODE(node_page));
1136 		max_addrs = DEF_ADDRS_PER_INODE;
1137 	} else {
1138 		base = 0;
1139 		max_addrs = DEF_ADDRS_PER_BLOCK;
1140 	}
1141 
1142 	if (base + ofs_in_node >= max_addrs) {
1143 		f2fs_err(sbi, "Inconsistent blkaddr offset: base:%u, ofs_in_node:%u, max:%u, ino:%u, nid:%u",
1144 			base, ofs_in_node, max_addrs, dni->ino, dni->nid);
1145 		f2fs_put_page(node_page, 1);
1146 		return false;
1147 	}
1148 
1149 	*nofs = ofs_of_node(node_page);
1150 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
1151 	f2fs_put_page(node_page, 1);
1152 
1153 	if (source_blkaddr != blkaddr) {
1154 #ifdef CONFIG_F2FS_CHECK_FS
1155 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
1156 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
1157 
1158 		if (unlikely(check_valid_map(sbi, segno, offset))) {
1159 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
1160 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u",
1161 					 blkaddr, source_blkaddr, segno);
1162 				set_sbi_flag(sbi, SBI_NEED_FSCK);
1163 			}
1164 		}
1165 #endif
1166 		return false;
1167 	}
1168 	return true;
1169 }
1170 
1171 static int ra_data_block(struct inode *inode, pgoff_t index)
1172 {
1173 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1174 	struct address_space *mapping = inode->i_mapping;
1175 	struct dnode_of_data dn;
1176 	struct page *page;
1177 	struct f2fs_io_info fio = {
1178 		.sbi = sbi,
1179 		.ino = inode->i_ino,
1180 		.type = DATA,
1181 		.temp = COLD,
1182 		.op = REQ_OP_READ,
1183 		.op_flags = 0,
1184 		.encrypted_page = NULL,
1185 		.in_list = 0,
1186 	};
1187 	int err;
1188 
1189 	page = f2fs_grab_cache_page(mapping, index, true);
1190 	if (!page)
1191 		return -ENOMEM;
1192 
1193 	if (f2fs_lookup_read_extent_cache_block(inode, index,
1194 						&dn.data_blkaddr)) {
1195 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1196 						DATA_GENERIC_ENHANCE_READ))) {
1197 			err = -EFSCORRUPTED;
1198 			goto put_page;
1199 		}
1200 		goto got_it;
1201 	}
1202 
1203 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1204 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
1205 	if (err)
1206 		goto put_page;
1207 	f2fs_put_dnode(&dn);
1208 
1209 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
1210 		err = -ENOENT;
1211 		goto put_page;
1212 	}
1213 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1214 						DATA_GENERIC_ENHANCE))) {
1215 		err = -EFSCORRUPTED;
1216 		goto put_page;
1217 	}
1218 got_it:
1219 	/* read page */
1220 	fio.page = page;
1221 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1222 
1223 	/*
1224 	 * don't cache encrypted data into meta inode until previous dirty
1225 	 * data were writebacked to avoid racing between GC and flush.
1226 	 */
1227 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1228 
1229 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1230 
1231 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
1232 					dn.data_blkaddr,
1233 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
1234 	if (!fio.encrypted_page) {
1235 		err = -ENOMEM;
1236 		goto put_page;
1237 	}
1238 
1239 	err = f2fs_submit_page_bio(&fio);
1240 	if (err)
1241 		goto put_encrypted_page;
1242 	f2fs_put_page(fio.encrypted_page, 0);
1243 	f2fs_put_page(page, 1);
1244 
1245 	f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
1246 	f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1247 
1248 	return 0;
1249 put_encrypted_page:
1250 	f2fs_put_page(fio.encrypted_page, 1);
1251 put_page:
1252 	f2fs_put_page(page, 1);
1253 	return err;
1254 }
1255 
1256 /*
1257  * Move data block via META_MAPPING while keeping locked data page.
1258  * This can be used to move blocks, aka LBAs, directly on disk.
1259  */
1260 static int move_data_block(struct inode *inode, block_t bidx,
1261 				int gc_type, unsigned int segno, int off)
1262 {
1263 	struct f2fs_io_info fio = {
1264 		.sbi = F2FS_I_SB(inode),
1265 		.ino = inode->i_ino,
1266 		.type = DATA,
1267 		.temp = COLD,
1268 		.op = REQ_OP_READ,
1269 		.op_flags = 0,
1270 		.encrypted_page = NULL,
1271 		.in_list = 0,
1272 	};
1273 	struct dnode_of_data dn;
1274 	struct f2fs_summary sum;
1275 	struct node_info ni;
1276 	struct page *page, *mpage;
1277 	block_t newaddr;
1278 	int err = 0;
1279 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
1280 	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
1281 				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
1282 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
1283 
1284 	/* do not read out */
1285 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
1286 	if (!page)
1287 		return -ENOMEM;
1288 
1289 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1290 		err = -ENOENT;
1291 		goto out;
1292 	}
1293 
1294 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1295 	if (err)
1296 		goto out;
1297 
1298 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1299 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
1300 	if (err)
1301 		goto out;
1302 
1303 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
1304 		ClearPageUptodate(page);
1305 		err = -ENOENT;
1306 		goto put_out;
1307 	}
1308 
1309 	/*
1310 	 * don't cache encrypted data into meta inode until previous dirty
1311 	 * data were writebacked to avoid racing between GC and flush.
1312 	 */
1313 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1314 
1315 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1316 
1317 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni, false);
1318 	if (err)
1319 		goto put_out;
1320 
1321 	/* read page */
1322 	fio.page = page;
1323 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1324 
1325 	if (lfs_mode)
1326 		f2fs_down_write(&fio.sbi->io_order_lock);
1327 
1328 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
1329 					fio.old_blkaddr, false);
1330 	if (!mpage) {
1331 		err = -ENOMEM;
1332 		goto up_out;
1333 	}
1334 
1335 	fio.encrypted_page = mpage;
1336 
1337 	/* read source block in mpage */
1338 	if (!PageUptodate(mpage)) {
1339 		err = f2fs_submit_page_bio(&fio);
1340 		if (err) {
1341 			f2fs_put_page(mpage, 1);
1342 			goto up_out;
1343 		}
1344 
1345 		f2fs_update_iostat(fio.sbi, inode, FS_DATA_READ_IO,
1346 							F2FS_BLKSIZE);
1347 		f2fs_update_iostat(fio.sbi, NULL, FS_GDATA_READ_IO,
1348 							F2FS_BLKSIZE);
1349 
1350 		lock_page(mpage);
1351 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
1352 						!PageUptodate(mpage))) {
1353 			err = -EIO;
1354 			f2fs_put_page(mpage, 1);
1355 			goto up_out;
1356 		}
1357 	}
1358 
1359 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
1360 
1361 	/* allocate block address */
1362 	err = f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
1363 				&sum, type, NULL);
1364 	if (err) {
1365 		f2fs_put_page(mpage, 1);
1366 		/* filesystem should shutdown, no need to recovery block */
1367 		goto up_out;
1368 	}
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 
1384 	f2fs_invalidate_internal_cache(fio.sbi, fio.old_blkaddr);
1385 
1386 	set_page_dirty(fio.encrypted_page);
1387 	if (clear_page_dirty_for_io(fio.encrypted_page))
1388 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
1389 
1390 	set_page_writeback(fio.encrypted_page);
1391 
1392 	fio.op = REQ_OP_WRITE;
1393 	fio.op_flags = REQ_SYNC;
1394 	fio.new_blkaddr = newaddr;
1395 	f2fs_submit_page_write(&fio);
1396 
1397 	f2fs_update_iostat(fio.sbi, NULL, FS_GC_DATA_IO, F2FS_BLKSIZE);
1398 
1399 	f2fs_update_data_blkaddr(&dn, newaddr);
1400 	set_inode_flag(inode, FI_APPEND_WRITE);
1401 
1402 	f2fs_put_page(fio.encrypted_page, 1);
1403 recover_block:
1404 	if (err)
1405 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
1406 							true, true, true);
1407 up_out:
1408 	if (lfs_mode)
1409 		f2fs_up_write(&fio.sbi->io_order_lock);
1410 put_out:
1411 	f2fs_put_dnode(&dn);
1412 out:
1413 	f2fs_put_page(page, 1);
1414 	return err;
1415 }
1416 
1417 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
1418 							unsigned int segno, int off)
1419 {
1420 	struct page *page;
1421 	int err = 0;
1422 
1423 	page = f2fs_get_lock_data_page(inode, bidx, true);
1424 	if (IS_ERR(page))
1425 		return PTR_ERR(page);
1426 
1427 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1428 		err = -ENOENT;
1429 		goto out;
1430 	}
1431 
1432 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1433 	if (err)
1434 		goto out;
1435 
1436 	if (gc_type == BG_GC) {
1437 		if (folio_test_writeback(page_folio(page))) {
1438 			err = -EAGAIN;
1439 			goto out;
1440 		}
1441 		set_page_dirty(page);
1442 		set_page_private_gcing(page);
1443 	} else {
1444 		struct f2fs_io_info fio = {
1445 			.sbi = F2FS_I_SB(inode),
1446 			.ino = inode->i_ino,
1447 			.type = DATA,
1448 			.temp = COLD,
1449 			.op = REQ_OP_WRITE,
1450 			.op_flags = REQ_SYNC,
1451 			.old_blkaddr = NULL_ADDR,
1452 			.page = page,
1453 			.encrypted_page = NULL,
1454 			.need_lock = LOCK_REQ,
1455 			.io_type = FS_GC_DATA_IO,
1456 		};
1457 		bool is_dirty = PageDirty(page);
1458 
1459 retry:
1460 		f2fs_wait_on_page_writeback(page, DATA, true, true);
1461 
1462 		set_page_dirty(page);
1463 		if (clear_page_dirty_for_io(page)) {
1464 			inode_dec_dirty_pages(inode);
1465 			f2fs_remove_dirty_inode(inode);
1466 		}
1467 
1468 		set_page_private_gcing(page);
1469 
1470 		err = f2fs_do_write_data_page(&fio);
1471 		if (err) {
1472 			clear_page_private_gcing(page);
1473 			if (err == -ENOMEM) {
1474 				memalloc_retry_wait(GFP_NOFS);
1475 				goto retry;
1476 			}
1477 			if (is_dirty)
1478 				set_page_dirty(page);
1479 		}
1480 	}
1481 out:
1482 	f2fs_put_page(page, 1);
1483 	return err;
1484 }
1485 
1486 /*
1487  * This function tries to get parent node of victim data block, and identifies
1488  * data block validity. If the block is valid, copy that with cold status and
1489  * modify parent node.
1490  * If the parent node is not valid or the data block address is different,
1491  * the victim data block is ignored.
1492  */
1493 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1494 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
1495 		bool force_migrate)
1496 {
1497 	struct super_block *sb = sbi->sb;
1498 	struct f2fs_summary *entry;
1499 	block_t start_addr;
1500 	int off;
1501 	int phase = 0;
1502 	int submitted = 0;
1503 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1504 
1505 	start_addr = START_BLOCK(sbi, segno);
1506 
1507 next_step:
1508 	entry = sum;
1509 
1510 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1511 		struct page *data_page;
1512 		struct inode *inode;
1513 		struct node_info dni; /* dnode info for the data */
1514 		unsigned int ofs_in_node, nofs;
1515 		block_t start_bidx;
1516 		nid_t nid = le32_to_cpu(entry->nid);
1517 
1518 		/*
1519 		 * stop BG_GC if there is not enough free sections.
1520 		 * Or, stop GC if the segment becomes fully valid caused by
1521 		 * race condition along with SSR block allocation.
1522 		 */
1523 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1524 			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
1525 							CAP_BLKS_PER_SEC(sbi)))
1526 			return submitted;
1527 
1528 		if (check_valid_map(sbi, segno, off) == 0)
1529 			continue;
1530 
1531 		if (phase == 0) {
1532 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1533 							META_NAT, true);
1534 			continue;
1535 		}
1536 
1537 		if (phase == 1) {
1538 			f2fs_ra_node_page(sbi, nid);
1539 			continue;
1540 		}
1541 
1542 		/* Get an inode by ino with checking validity */
1543 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1544 			continue;
1545 
1546 		if (phase == 2) {
1547 			f2fs_ra_node_page(sbi, dni.ino);
1548 			continue;
1549 		}
1550 
1551 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1552 
1553 		if (phase == 3) {
1554 			int err;
1555 
1556 			inode = f2fs_iget(sb, dni.ino);
1557 			if (IS_ERR(inode))
1558 				continue;
1559 
1560 			if (is_bad_inode(inode) ||
1561 					special_file(inode->i_mode)) {
1562 				iput(inode);
1563 				continue;
1564 			}
1565 
1566 			err = f2fs_gc_pinned_control(inode, gc_type, segno);
1567 			if (err == -EAGAIN) {
1568 				iput(inode);
1569 				return submitted;
1570 			}
1571 
1572 			if (!f2fs_down_write_trylock(
1573 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1574 				iput(inode);
1575 				sbi->skipped_gc_rwsem++;
1576 				continue;
1577 			}
1578 
1579 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1580 								ofs_in_node;
1581 
1582 			if (f2fs_post_read_required(inode)) {
1583 				int err = ra_data_block(inode, start_bidx);
1584 
1585 				f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1586 				if (err) {
1587 					iput(inode);
1588 					continue;
1589 				}
1590 				add_gc_inode(gc_list, inode);
1591 				continue;
1592 			}
1593 
1594 			data_page = f2fs_get_read_data_page(inode, start_bidx,
1595 							REQ_RAHEAD, true, NULL);
1596 			f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1597 			if (IS_ERR(data_page)) {
1598 				iput(inode);
1599 				continue;
1600 			}
1601 
1602 			f2fs_put_page(data_page, 0);
1603 			add_gc_inode(gc_list, inode);
1604 			continue;
1605 		}
1606 
1607 		/* phase 4 */
1608 		inode = find_gc_inode(gc_list, dni.ino);
1609 		if (inode) {
1610 			struct f2fs_inode_info *fi = F2FS_I(inode);
1611 			bool locked = false;
1612 			int err;
1613 
1614 			if (S_ISREG(inode->i_mode)) {
1615 				if (!f2fs_down_write_trylock(&fi->i_gc_rwsem[WRITE])) {
1616 					sbi->skipped_gc_rwsem++;
1617 					continue;
1618 				}
1619 				if (!f2fs_down_write_trylock(
1620 						&fi->i_gc_rwsem[READ])) {
1621 					sbi->skipped_gc_rwsem++;
1622 					f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
1623 					continue;
1624 				}
1625 				locked = true;
1626 
1627 				/* wait for all inflight aio data */
1628 				inode_dio_wait(inode);
1629 			}
1630 
1631 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1632 								+ ofs_in_node;
1633 			if (f2fs_post_read_required(inode))
1634 				err = move_data_block(inode, start_bidx,
1635 							gc_type, segno, off);
1636 			else
1637 				err = move_data_page(inode, start_bidx, gc_type,
1638 								segno, off);
1639 
1640 			if (!err && (gc_type == FG_GC ||
1641 					f2fs_post_read_required(inode)))
1642 				submitted++;
1643 
1644 			if (locked) {
1645 				f2fs_up_write(&fi->i_gc_rwsem[READ]);
1646 				f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
1647 			}
1648 
1649 			stat_inc_data_blk_count(sbi, 1, gc_type);
1650 		}
1651 	}
1652 
1653 	if (++phase < 5)
1654 		goto next_step;
1655 
1656 	return submitted;
1657 }
1658 
1659 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1660 			int gc_type)
1661 {
1662 	struct sit_info *sit_i = SIT_I(sbi);
1663 	int ret;
1664 
1665 	down_write(&sit_i->sentry_lock);
1666 	ret = f2fs_get_victim(sbi, victim, gc_type, NO_CHECK_TYPE, LFS, 0);
1667 	up_write(&sit_i->sentry_lock);
1668 	return ret;
1669 }
1670 
1671 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1672 				unsigned int start_segno,
1673 				struct gc_inode_list *gc_list, int gc_type,
1674 				bool force_migrate)
1675 {
1676 	struct page *sum_page;
1677 	struct f2fs_summary_block *sum;
1678 	struct blk_plug plug;
1679 	unsigned int segno = start_segno;
1680 	unsigned int end_segno = start_segno + SEGS_PER_SEC(sbi);
1681 	int seg_freed = 0, migrated = 0;
1682 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1683 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1684 	unsigned char data_type = (type == SUM_TYPE_DATA) ? DATA : NODE;
1685 	int submitted = 0;
1686 
1687 	if (__is_large_section(sbi))
1688 		end_segno = rounddown(end_segno, SEGS_PER_SEC(sbi));
1689 
1690 	/*
1691 	 * zone-capacity can be less than zone-size in zoned devices,
1692 	 * resulting in less than expected usable segments in the zone,
1693 	 * calculate the end segno in the zone which can be garbage collected
1694 	 */
1695 	if (f2fs_sb_has_blkzoned(sbi))
1696 		end_segno -= SEGS_PER_SEC(sbi) -
1697 					f2fs_usable_segs_in_sec(sbi, segno);
1698 
1699 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
1700 
1701 	/* readahead multi ssa blocks those have contiguous address */
1702 	if (__is_large_section(sbi))
1703 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1704 					end_segno - segno, META_SSA, true);
1705 
1706 	/* reference all summary page */
1707 	while (segno < end_segno) {
1708 		sum_page = f2fs_get_sum_page(sbi, segno++);
1709 		if (IS_ERR(sum_page)) {
1710 			int err = PTR_ERR(sum_page);
1711 
1712 			end_segno = segno - 1;
1713 			for (segno = start_segno; segno < end_segno; segno++) {
1714 				sum_page = find_get_page(META_MAPPING(sbi),
1715 						GET_SUM_BLOCK(sbi, segno));
1716 				f2fs_put_page(sum_page, 0);
1717 				f2fs_put_page(sum_page, 0);
1718 			}
1719 			return err;
1720 		}
1721 		unlock_page(sum_page);
1722 	}
1723 
1724 	blk_start_plug(&plug);
1725 
1726 	for (segno = start_segno; segno < end_segno; segno++) {
1727 
1728 		/* find segment summary of victim */
1729 		sum_page = find_get_page(META_MAPPING(sbi),
1730 					GET_SUM_BLOCK(sbi, segno));
1731 		f2fs_put_page(sum_page, 0);
1732 
1733 		if (get_valid_blocks(sbi, segno, false) == 0)
1734 			goto freed;
1735 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1736 				migrated >= sbi->migration_granularity)
1737 			goto skip;
1738 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1739 			goto skip;
1740 
1741 		sum = page_address(sum_page);
1742 		if (type != GET_SUM_TYPE((&sum->footer))) {
1743 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1744 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1745 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1746 			f2fs_stop_checkpoint(sbi, false,
1747 				STOP_CP_REASON_CORRUPTED_SUMMARY);
1748 			goto skip;
1749 		}
1750 
1751 		/*
1752 		 * this is to avoid deadlock:
1753 		 * - lock_page(sum_page)         - f2fs_replace_block
1754 		 *  - check_valid_map()            - down_write(sentry_lock)
1755 		 *   - down_read(sentry_lock)     - change_curseg()
1756 		 *                                  - lock_page(sum_page)
1757 		 */
1758 		if (type == SUM_TYPE_NODE)
1759 			submitted += gc_node_segment(sbi, sum->entries, segno,
1760 								gc_type);
1761 		else
1762 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1763 							segno, gc_type,
1764 							force_migrate);
1765 
1766 		stat_inc_gc_seg_count(sbi, data_type, gc_type);
1767 		sbi->gc_reclaimed_segs[sbi->gc_mode]++;
1768 		migrated++;
1769 
1770 freed:
1771 		if (gc_type == FG_GC &&
1772 				get_valid_blocks(sbi, segno, false) == 0)
1773 			seg_freed++;
1774 
1775 		if (__is_large_section(sbi))
1776 			sbi->next_victim_seg[gc_type] =
1777 				(segno + 1 < end_segno) ? segno + 1 : NULL_SEGNO;
1778 skip:
1779 		f2fs_put_page(sum_page, 0);
1780 	}
1781 
1782 	if (submitted)
1783 		f2fs_submit_merged_write(sbi, data_type);
1784 
1785 	blk_finish_plug(&plug);
1786 
1787 	if (migrated)
1788 		stat_inc_gc_sec_count(sbi, data_type, gc_type);
1789 
1790 	return seg_freed;
1791 }
1792 
1793 int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
1794 {
1795 	int gc_type = gc_control->init_gc_type;
1796 	unsigned int segno = gc_control->victim_segno;
1797 	int sec_freed = 0, seg_freed = 0, total_freed = 0, total_sec_freed = 0;
1798 	int ret = 0;
1799 	struct cp_control cpc;
1800 	struct gc_inode_list gc_list = {
1801 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1802 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1803 	};
1804 	unsigned int skipped_round = 0, round = 0;
1805 	unsigned int upper_secs;
1806 
1807 	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
1808 				gc_control->nr_free_secs,
1809 				get_pages(sbi, F2FS_DIRTY_NODES),
1810 				get_pages(sbi, F2FS_DIRTY_DENTS),
1811 				get_pages(sbi, F2FS_DIRTY_IMETA),
1812 				free_sections(sbi),
1813 				free_segments(sbi),
1814 				reserved_segments(sbi),
1815 				prefree_segments(sbi));
1816 
1817 	cpc.reason = __get_cp_reason(sbi);
1818 gc_more:
1819 	sbi->skipped_gc_rwsem = 0;
1820 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1821 		ret = -EINVAL;
1822 		goto stop;
1823 	}
1824 	if (unlikely(f2fs_cp_error(sbi))) {
1825 		ret = -EIO;
1826 		goto stop;
1827 	}
1828 
1829 	/* Let's run FG_GC, if we don't have enough space. */
1830 	if (has_not_enough_free_secs(sbi, 0, 0)) {
1831 		gc_type = FG_GC;
1832 
1833 		/*
1834 		 * For example, if there are many prefree_segments below given
1835 		 * threshold, we can make them free by checkpoint. Then, we
1836 		 * secure free segments which doesn't need fggc any more.
1837 		 */
1838 		if (prefree_segments(sbi)) {
1839 			stat_inc_cp_call_count(sbi, TOTAL_CALL);
1840 			ret = f2fs_write_checkpoint(sbi, &cpc);
1841 			if (ret)
1842 				goto stop;
1843 			/* Reset due to checkpoint */
1844 			sec_freed = 0;
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 	if (seg_freed < 0)
1868 		goto stop;
1869 
1870 	total_freed += seg_freed;
1871 
1872 	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno)) {
1873 		sec_freed++;
1874 		total_sec_freed++;
1875 	}
1876 
1877 	if (gc_type == FG_GC) {
1878 		sbi->cur_victim_sec = NULL_SEGNO;
1879 
1880 		if (has_enough_free_secs(sbi, sec_freed, 0)) {
1881 			if (!gc_control->no_bg_gc &&
1882 			    total_sec_freed < gc_control->nr_free_secs)
1883 				goto go_gc_more;
1884 			goto stop;
1885 		}
1886 		if (sbi->skipped_gc_rwsem)
1887 			skipped_round++;
1888 		round++;
1889 		if (skipped_round > MAX_SKIP_GC_COUNT &&
1890 				skipped_round * 2 >= round) {
1891 			stat_inc_cp_call_count(sbi, TOTAL_CALL);
1892 			ret = f2fs_write_checkpoint(sbi, &cpc);
1893 			goto stop;
1894 		}
1895 	} else if (has_enough_free_secs(sbi, 0, 0)) {
1896 		goto stop;
1897 	}
1898 
1899 	__get_secs_required(sbi, NULL, &upper_secs, NULL);
1900 
1901 	/*
1902 	 * Write checkpoint to reclaim prefree segments.
1903 	 * We need more three extra sections for writer's data/node/dentry.
1904 	 */
1905 	if (free_sections(sbi) <= upper_secs + NR_GC_CHECKPOINT_SECS &&
1906 				prefree_segments(sbi)) {
1907 		stat_inc_cp_call_count(sbi, TOTAL_CALL);
1908 		ret = f2fs_write_checkpoint(sbi, &cpc);
1909 		if (ret)
1910 			goto stop;
1911 		/* Reset due to checkpoint */
1912 		sec_freed = 0;
1913 	}
1914 go_gc_more:
1915 	segno = NULL_SEGNO;
1916 	goto gc_more;
1917 
1918 stop:
1919 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1920 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = gc_control->victim_segno;
1921 
1922 	if (gc_type == FG_GC)
1923 		f2fs_unpin_all_sections(sbi, true);
1924 
1925 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, total_sec_freed,
1926 				get_pages(sbi, F2FS_DIRTY_NODES),
1927 				get_pages(sbi, F2FS_DIRTY_DENTS),
1928 				get_pages(sbi, F2FS_DIRTY_IMETA),
1929 				free_sections(sbi),
1930 				free_segments(sbi),
1931 				reserved_segments(sbi),
1932 				prefree_segments(sbi));
1933 
1934 	f2fs_up_write(&sbi->gc_lock);
1935 
1936 	put_gc_inode(&gc_list);
1937 
1938 	if (gc_control->err_gc_skipped && !ret)
1939 		ret = total_sec_freed ? 0 : -EAGAIN;
1940 	return ret;
1941 }
1942 
1943 int __init f2fs_create_garbage_collection_cache(void)
1944 {
1945 	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
1946 					sizeof(struct victim_entry));
1947 	return victim_entry_slab ? 0 : -ENOMEM;
1948 }
1949 
1950 void f2fs_destroy_garbage_collection_cache(void)
1951 {
1952 	kmem_cache_destroy(victim_entry_slab);
1953 }
1954 
1955 static void init_atgc_management(struct f2fs_sb_info *sbi)
1956 {
1957 	struct atgc_management *am = &sbi->am;
1958 
1959 	if (test_opt(sbi, ATGC) &&
1960 		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
1961 		am->atgc_enabled = true;
1962 
1963 	am->root = RB_ROOT_CACHED;
1964 	INIT_LIST_HEAD(&am->victim_list);
1965 	am->victim_count = 0;
1966 
1967 	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
1968 	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
1969 	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
1970 	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
1971 }
1972 
1973 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1974 {
1975 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1976 
1977 	/* give warm/cold data area from slower device */
1978 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1979 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1980 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1981 
1982 	init_atgc_management(sbi);
1983 }
1984 
1985 int f2fs_gc_range(struct f2fs_sb_info *sbi,
1986 		unsigned int start_seg, unsigned int end_seg,
1987 		bool dry_run, unsigned int dry_run_sections)
1988 {
1989 	unsigned int segno;
1990 	unsigned int gc_secs = dry_run_sections;
1991 
1992 	if (unlikely(f2fs_cp_error(sbi)))
1993 		return -EIO;
1994 
1995 	for (segno = start_seg; segno <= end_seg; segno += SEGS_PER_SEC(sbi)) {
1996 		struct gc_inode_list gc_list = {
1997 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1998 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1999 		};
2000 
2001 		do_garbage_collect(sbi, segno, &gc_list, FG_GC,
2002 						dry_run_sections == 0);
2003 		put_gc_inode(&gc_list);
2004 
2005 		if (!dry_run && get_valid_blocks(sbi, segno, true))
2006 			return -EAGAIN;
2007 		if (dry_run && dry_run_sections &&
2008 		    !get_valid_blocks(sbi, segno, true) && --gc_secs == 0)
2009 			break;
2010 
2011 		if (fatal_signal_pending(current))
2012 			return -ERESTARTSYS;
2013 	}
2014 
2015 	return 0;
2016 }
2017 
2018 static int free_segment_range(struct f2fs_sb_info *sbi,
2019 				unsigned int secs, bool dry_run)
2020 {
2021 	unsigned int next_inuse, start, end;
2022 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
2023 	int gc_mode, gc_type;
2024 	int err = 0;
2025 	int type;
2026 
2027 	/* Force block allocation for GC */
2028 	MAIN_SECS(sbi) -= secs;
2029 	start = MAIN_SECS(sbi) * SEGS_PER_SEC(sbi);
2030 	end = MAIN_SEGS(sbi) - 1;
2031 
2032 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
2033 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
2034 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
2035 			SIT_I(sbi)->last_victim[gc_mode] = 0;
2036 
2037 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
2038 		if (sbi->next_victim_seg[gc_type] >= start)
2039 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
2040 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
2041 
2042 	/* Move out cursegs from the target range */
2043 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++) {
2044 		err = f2fs_allocate_segment_for_resize(sbi, type, start, end);
2045 		if (err)
2046 			goto out;
2047 	}
2048 
2049 	/* do GC to move out valid blocks in the range */
2050 	err = f2fs_gc_range(sbi, start, end, dry_run, 0);
2051 	if (err || dry_run)
2052 		goto out;
2053 
2054 	stat_inc_cp_call_count(sbi, TOTAL_CALL);
2055 	err = f2fs_write_checkpoint(sbi, &cpc);
2056 	if (err)
2057 		goto out;
2058 
2059 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
2060 	if (next_inuse <= end) {
2061 		f2fs_err(sbi, "segno %u should be free but still inuse!",
2062 			 next_inuse);
2063 		f2fs_bug_on(sbi, 1);
2064 	}
2065 out:
2066 	MAIN_SECS(sbi) += secs;
2067 	return err;
2068 }
2069 
2070 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
2071 {
2072 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
2073 	int section_count;
2074 	int segment_count;
2075 	int segment_count_main;
2076 	long long block_count;
2077 	int segs = secs * SEGS_PER_SEC(sbi);
2078 
2079 	f2fs_down_write(&sbi->sb_lock);
2080 
2081 	section_count = le32_to_cpu(raw_sb->section_count);
2082 	segment_count = le32_to_cpu(raw_sb->segment_count);
2083 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
2084 	block_count = le64_to_cpu(raw_sb->block_count);
2085 
2086 	raw_sb->section_count = cpu_to_le32(section_count + secs);
2087 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
2088 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
2089 	raw_sb->block_count = cpu_to_le64(block_count +
2090 			(long long)SEGS_TO_BLKS(sbi, segs));
2091 	if (f2fs_is_multi_device(sbi)) {
2092 		int last_dev = sbi->s_ndevs - 1;
2093 		int dev_segs =
2094 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
2095 
2096 		raw_sb->devs[last_dev].total_segments =
2097 						cpu_to_le32(dev_segs + segs);
2098 	}
2099 
2100 	f2fs_up_write(&sbi->sb_lock);
2101 }
2102 
2103 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
2104 {
2105 	int segs = secs * SEGS_PER_SEC(sbi);
2106 	long long blks = SEGS_TO_BLKS(sbi, segs);
2107 	long long user_block_count =
2108 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
2109 
2110 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
2111 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
2112 	MAIN_SECS(sbi) += secs;
2113 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
2114 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
2115 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
2116 
2117 	if (f2fs_is_multi_device(sbi)) {
2118 		int last_dev = sbi->s_ndevs - 1;
2119 
2120 		FDEV(last_dev).total_segments =
2121 				(int)FDEV(last_dev).total_segments + segs;
2122 		FDEV(last_dev).end_blk =
2123 				(long long)FDEV(last_dev).end_blk + blks;
2124 #ifdef CONFIG_BLK_DEV_ZONED
2125 		FDEV(last_dev).nr_blkz = FDEV(last_dev).nr_blkz +
2126 					div_u64(blks, sbi->blocks_per_blkz);
2127 #endif
2128 	}
2129 }
2130 
2131 int f2fs_resize_fs(struct file *filp, __u64 block_count)
2132 {
2133 	struct f2fs_sb_info *sbi = F2FS_I_SB(file_inode(filp));
2134 	__u64 old_block_count, shrunk_blocks;
2135 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
2136 	unsigned int secs;
2137 	int err = 0;
2138 	__u32 rem;
2139 
2140 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
2141 	if (block_count > old_block_count)
2142 		return -EINVAL;
2143 
2144 	if (f2fs_is_multi_device(sbi)) {
2145 		int last_dev = sbi->s_ndevs - 1;
2146 		__u64 last_segs = FDEV(last_dev).total_segments;
2147 
2148 		if (block_count + SEGS_TO_BLKS(sbi, last_segs) <=
2149 								old_block_count)
2150 			return -EINVAL;
2151 	}
2152 
2153 	/* new fs size should align to section size */
2154 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
2155 	if (rem)
2156 		return -EINVAL;
2157 
2158 	if (block_count == old_block_count)
2159 		return 0;
2160 
2161 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
2162 		f2fs_err(sbi, "Should run fsck to repair first.");
2163 		return -EFSCORRUPTED;
2164 	}
2165 
2166 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
2167 		f2fs_err(sbi, "Checkpoint should be enabled.");
2168 		return -EINVAL;
2169 	}
2170 
2171 	err = mnt_want_write_file(filp);
2172 	if (err)
2173 		return err;
2174 
2175 	shrunk_blocks = old_block_count - block_count;
2176 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
2177 
2178 	/* stop other GC */
2179 	if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
2180 		err = -EAGAIN;
2181 		goto out_drop_write;
2182 	}
2183 
2184 	/* stop CP to protect MAIN_SEC in free_segment_range */
2185 	f2fs_lock_op(sbi);
2186 
2187 	spin_lock(&sbi->stat_lock);
2188 	if (shrunk_blocks + valid_user_blocks(sbi) +
2189 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2190 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2191 		err = -ENOSPC;
2192 	spin_unlock(&sbi->stat_lock);
2193 
2194 	if (err)
2195 		goto out_unlock;
2196 
2197 	err = free_segment_range(sbi, secs, true);
2198 
2199 out_unlock:
2200 	f2fs_unlock_op(sbi);
2201 	f2fs_up_write(&sbi->gc_lock);
2202 out_drop_write:
2203 	mnt_drop_write_file(filp);
2204 	if (err)
2205 		return err;
2206 
2207 	err = freeze_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
2208 	if (err)
2209 		return err;
2210 
2211 	if (f2fs_readonly(sbi->sb)) {
2212 		err = thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
2213 		if (err)
2214 			return err;
2215 		return -EROFS;
2216 	}
2217 
2218 	f2fs_down_write(&sbi->gc_lock);
2219 	f2fs_down_write(&sbi->cp_global_sem);
2220 
2221 	spin_lock(&sbi->stat_lock);
2222 	if (shrunk_blocks + valid_user_blocks(sbi) +
2223 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2224 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2225 		err = -ENOSPC;
2226 	else
2227 		sbi->user_block_count -= shrunk_blocks;
2228 	spin_unlock(&sbi->stat_lock);
2229 	if (err)
2230 		goto out_err;
2231 
2232 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
2233 	err = free_segment_range(sbi, secs, false);
2234 	if (err)
2235 		goto recover_out;
2236 
2237 	update_sb_metadata(sbi, -secs);
2238 
2239 	err = f2fs_commit_super(sbi, false);
2240 	if (err) {
2241 		update_sb_metadata(sbi, secs);
2242 		goto recover_out;
2243 	}
2244 
2245 	update_fs_metadata(sbi, -secs);
2246 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2247 	set_sbi_flag(sbi, SBI_IS_DIRTY);
2248 
2249 	stat_inc_cp_call_count(sbi, TOTAL_CALL);
2250 	err = f2fs_write_checkpoint(sbi, &cpc);
2251 	if (err) {
2252 		update_fs_metadata(sbi, secs);
2253 		update_sb_metadata(sbi, secs);
2254 		f2fs_commit_super(sbi, false);
2255 	}
2256 recover_out:
2257 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2258 	if (err) {
2259 		set_sbi_flag(sbi, SBI_NEED_FSCK);
2260 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
2261 
2262 		spin_lock(&sbi->stat_lock);
2263 		sbi->user_block_count += shrunk_blocks;
2264 		spin_unlock(&sbi->stat_lock);
2265 	}
2266 out_err:
2267 	f2fs_up_write(&sbi->cp_global_sem);
2268 	f2fs_up_write(&sbi->gc_lock);
2269 	thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
2270 	return err;
2271 }
2272