xref: /linux/fs/f2fs/gc.c (revision 8bc7c5e525584903ea83332e18a2118ed3b1985e)
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 = f2fs_is_cow_file(inode) ?
1175 				F2FS_I(inode)->atomic_inode->i_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 	};
1188 	int err;
1189 
1190 	page = f2fs_grab_cache_page(mapping, index, true);
1191 	if (!page)
1192 		return -ENOMEM;
1193 
1194 	if (f2fs_lookup_read_extent_cache_block(inode, index,
1195 						&dn.data_blkaddr)) {
1196 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1197 						DATA_GENERIC_ENHANCE_READ))) {
1198 			err = -EFSCORRUPTED;
1199 			goto put_page;
1200 		}
1201 		goto got_it;
1202 	}
1203 
1204 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1205 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
1206 	if (err)
1207 		goto put_page;
1208 	f2fs_put_dnode(&dn);
1209 
1210 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
1211 		err = -ENOENT;
1212 		goto put_page;
1213 	}
1214 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1215 						DATA_GENERIC_ENHANCE))) {
1216 		err = -EFSCORRUPTED;
1217 		goto put_page;
1218 	}
1219 got_it:
1220 	/* read page */
1221 	fio.page = page;
1222 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1223 
1224 	/*
1225 	 * don't cache encrypted data into meta inode until previous dirty
1226 	 * data were writebacked to avoid racing between GC and flush.
1227 	 */
1228 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1229 
1230 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1231 
1232 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
1233 					dn.data_blkaddr,
1234 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
1235 	if (!fio.encrypted_page) {
1236 		err = -ENOMEM;
1237 		goto put_page;
1238 	}
1239 
1240 	err = f2fs_submit_page_bio(&fio);
1241 	if (err)
1242 		goto put_encrypted_page;
1243 	f2fs_put_page(fio.encrypted_page, 0);
1244 	f2fs_put_page(page, 1);
1245 
1246 	f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
1247 	f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1248 
1249 	return 0;
1250 put_encrypted_page:
1251 	f2fs_put_page(fio.encrypted_page, 1);
1252 put_page:
1253 	f2fs_put_page(page, 1);
1254 	return err;
1255 }
1256 
1257 /*
1258  * Move data block via META_MAPPING while keeping locked data page.
1259  * This can be used to move blocks, aka LBAs, directly on disk.
1260  */
1261 static int move_data_block(struct inode *inode, block_t bidx,
1262 				int gc_type, unsigned int segno, int off)
1263 {
1264 	struct address_space *mapping = f2fs_is_cow_file(inode) ?
1265 				F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping;
1266 	struct f2fs_io_info fio = {
1267 		.sbi = F2FS_I_SB(inode),
1268 		.ino = inode->i_ino,
1269 		.type = DATA,
1270 		.temp = COLD,
1271 		.op = REQ_OP_READ,
1272 		.op_flags = 0,
1273 		.encrypted_page = NULL,
1274 		.in_list = 0,
1275 	};
1276 	struct dnode_of_data dn;
1277 	struct f2fs_summary sum;
1278 	struct node_info ni;
1279 	struct page *page, *mpage;
1280 	block_t newaddr;
1281 	int err = 0;
1282 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
1283 	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
1284 				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
1285 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
1286 
1287 	/* do not read out */
1288 	page = f2fs_grab_cache_page(mapping, bidx, false);
1289 	if (!page)
1290 		return -ENOMEM;
1291 
1292 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1293 		err = -ENOENT;
1294 		goto out;
1295 	}
1296 
1297 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1298 	if (err)
1299 		goto out;
1300 
1301 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1302 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
1303 	if (err)
1304 		goto out;
1305 
1306 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
1307 		ClearPageUptodate(page);
1308 		err = -ENOENT;
1309 		goto put_out;
1310 	}
1311 
1312 	/*
1313 	 * don't cache encrypted data into meta inode until previous dirty
1314 	 * data were writebacked to avoid racing between GC and flush.
1315 	 */
1316 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1317 
1318 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1319 
1320 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni, false);
1321 	if (err)
1322 		goto put_out;
1323 
1324 	/* read page */
1325 	fio.page = page;
1326 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1327 
1328 	if (lfs_mode)
1329 		f2fs_down_write(&fio.sbi->io_order_lock);
1330 
1331 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
1332 					fio.old_blkaddr, false);
1333 	if (!mpage) {
1334 		err = -ENOMEM;
1335 		goto up_out;
1336 	}
1337 
1338 	fio.encrypted_page = mpage;
1339 
1340 	/* read source block in mpage */
1341 	if (!PageUptodate(mpage)) {
1342 		err = f2fs_submit_page_bio(&fio);
1343 		if (err) {
1344 			f2fs_put_page(mpage, 1);
1345 			goto up_out;
1346 		}
1347 
1348 		f2fs_update_iostat(fio.sbi, inode, FS_DATA_READ_IO,
1349 							F2FS_BLKSIZE);
1350 		f2fs_update_iostat(fio.sbi, NULL, FS_GDATA_READ_IO,
1351 							F2FS_BLKSIZE);
1352 
1353 		lock_page(mpage);
1354 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
1355 						!PageUptodate(mpage))) {
1356 			err = -EIO;
1357 			f2fs_put_page(mpage, 1);
1358 			goto up_out;
1359 		}
1360 	}
1361 
1362 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
1363 
1364 	/* allocate block address */
1365 	err = f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
1366 				&sum, type, NULL);
1367 	if (err) {
1368 		f2fs_put_page(mpage, 1);
1369 		/* filesystem should shutdown, no need to recovery block */
1370 		goto up_out;
1371 	}
1372 
1373 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
1374 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
1375 	if (!fio.encrypted_page) {
1376 		err = -ENOMEM;
1377 		f2fs_put_page(mpage, 1);
1378 		goto recover_block;
1379 	}
1380 
1381 	/* write target block */
1382 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
1383 	memcpy(page_address(fio.encrypted_page),
1384 				page_address(mpage), PAGE_SIZE);
1385 	f2fs_put_page(mpage, 1);
1386 
1387 	f2fs_invalidate_internal_cache(fio.sbi, fio.old_blkaddr);
1388 
1389 	set_page_dirty(fio.encrypted_page);
1390 	if (clear_page_dirty_for_io(fio.encrypted_page))
1391 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
1392 
1393 	set_page_writeback(fio.encrypted_page);
1394 
1395 	fio.op = REQ_OP_WRITE;
1396 	fio.op_flags = REQ_SYNC;
1397 	fio.new_blkaddr = newaddr;
1398 	f2fs_submit_page_write(&fio);
1399 
1400 	f2fs_update_iostat(fio.sbi, NULL, FS_GC_DATA_IO, F2FS_BLKSIZE);
1401 
1402 	f2fs_update_data_blkaddr(&dn, newaddr);
1403 	set_inode_flag(inode, FI_APPEND_WRITE);
1404 
1405 	f2fs_put_page(fio.encrypted_page, 1);
1406 recover_block:
1407 	if (err)
1408 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
1409 							true, true, true);
1410 up_out:
1411 	if (lfs_mode)
1412 		f2fs_up_write(&fio.sbi->io_order_lock);
1413 put_out:
1414 	f2fs_put_dnode(&dn);
1415 out:
1416 	f2fs_put_page(page, 1);
1417 	return err;
1418 }
1419 
1420 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
1421 							unsigned int segno, int off)
1422 {
1423 	struct page *page;
1424 	int err = 0;
1425 
1426 	page = f2fs_get_lock_data_page(inode, bidx, true);
1427 	if (IS_ERR(page))
1428 		return PTR_ERR(page);
1429 
1430 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1431 		err = -ENOENT;
1432 		goto out;
1433 	}
1434 
1435 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1436 	if (err)
1437 		goto out;
1438 
1439 	if (gc_type == BG_GC) {
1440 		if (folio_test_writeback(page_folio(page))) {
1441 			err = -EAGAIN;
1442 			goto out;
1443 		}
1444 		set_page_dirty(page);
1445 		set_page_private_gcing(page);
1446 	} else {
1447 		struct f2fs_io_info fio = {
1448 			.sbi = F2FS_I_SB(inode),
1449 			.ino = inode->i_ino,
1450 			.type = DATA,
1451 			.temp = COLD,
1452 			.op = REQ_OP_WRITE,
1453 			.op_flags = REQ_SYNC,
1454 			.old_blkaddr = NULL_ADDR,
1455 			.page = page,
1456 			.encrypted_page = NULL,
1457 			.need_lock = LOCK_REQ,
1458 			.io_type = FS_GC_DATA_IO,
1459 		};
1460 		bool is_dirty = PageDirty(page);
1461 
1462 retry:
1463 		f2fs_wait_on_page_writeback(page, DATA, true, true);
1464 
1465 		set_page_dirty(page);
1466 		if (clear_page_dirty_for_io(page)) {
1467 			inode_dec_dirty_pages(inode);
1468 			f2fs_remove_dirty_inode(inode);
1469 		}
1470 
1471 		set_page_private_gcing(page);
1472 
1473 		err = f2fs_do_write_data_page(&fio);
1474 		if (err) {
1475 			clear_page_private_gcing(page);
1476 			if (err == -ENOMEM) {
1477 				memalloc_retry_wait(GFP_NOFS);
1478 				goto retry;
1479 			}
1480 			if (is_dirty)
1481 				set_page_dirty(page);
1482 		}
1483 	}
1484 out:
1485 	f2fs_put_page(page, 1);
1486 	return err;
1487 }
1488 
1489 /*
1490  * This function tries to get parent node of victim data block, and identifies
1491  * data block validity. If the block is valid, copy that with cold status and
1492  * modify parent node.
1493  * If the parent node is not valid or the data block address is different,
1494  * the victim data block is ignored.
1495  */
1496 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1497 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
1498 		bool force_migrate)
1499 {
1500 	struct super_block *sb = sbi->sb;
1501 	struct f2fs_summary *entry;
1502 	block_t start_addr;
1503 	int off;
1504 	int phase = 0;
1505 	int submitted = 0;
1506 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1507 
1508 	start_addr = START_BLOCK(sbi, segno);
1509 
1510 next_step:
1511 	entry = sum;
1512 
1513 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1514 		struct page *data_page;
1515 		struct inode *inode;
1516 		struct node_info dni; /* dnode info for the data */
1517 		unsigned int ofs_in_node, nofs;
1518 		block_t start_bidx;
1519 		nid_t nid = le32_to_cpu(entry->nid);
1520 
1521 		/*
1522 		 * stop BG_GC if there is not enough free sections.
1523 		 * Or, stop GC if the segment becomes fully valid caused by
1524 		 * race condition along with SSR block allocation.
1525 		 */
1526 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1527 			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
1528 							CAP_BLKS_PER_SEC(sbi)))
1529 			return submitted;
1530 
1531 		if (check_valid_map(sbi, segno, off) == 0)
1532 			continue;
1533 
1534 		if (phase == 0) {
1535 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1536 							META_NAT, true);
1537 			continue;
1538 		}
1539 
1540 		if (phase == 1) {
1541 			f2fs_ra_node_page(sbi, nid);
1542 			continue;
1543 		}
1544 
1545 		/* Get an inode by ino with checking validity */
1546 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1547 			continue;
1548 
1549 		if (phase == 2) {
1550 			f2fs_ra_node_page(sbi, dni.ino);
1551 			continue;
1552 		}
1553 
1554 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1555 
1556 		if (phase == 3) {
1557 			int err;
1558 
1559 			inode = f2fs_iget(sb, dni.ino);
1560 			if (IS_ERR(inode))
1561 				continue;
1562 
1563 			if (is_bad_inode(inode) ||
1564 					special_file(inode->i_mode)) {
1565 				iput(inode);
1566 				continue;
1567 			}
1568 
1569 			if (f2fs_has_inline_data(inode)) {
1570 				iput(inode);
1571 				set_sbi_flag(sbi, SBI_NEED_FSCK);
1572 				f2fs_err_ratelimited(sbi,
1573 					"inode %lx has both inline_data flag and "
1574 					"data block, nid=%u, ofs_in_node=%u",
1575 					inode->i_ino, dni.nid, ofs_in_node);
1576 				continue;
1577 			}
1578 
1579 			err = f2fs_gc_pinned_control(inode, gc_type, segno);
1580 			if (err == -EAGAIN) {
1581 				iput(inode);
1582 				return submitted;
1583 			}
1584 
1585 			if (!f2fs_down_write_trylock(
1586 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1587 				iput(inode);
1588 				sbi->skipped_gc_rwsem++;
1589 				continue;
1590 			}
1591 
1592 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1593 								ofs_in_node;
1594 
1595 			if (f2fs_meta_inode_gc_required(inode)) {
1596 				int err = ra_data_block(inode, start_bidx);
1597 
1598 				f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1599 				if (err) {
1600 					iput(inode);
1601 					continue;
1602 				}
1603 				add_gc_inode(gc_list, inode);
1604 				continue;
1605 			}
1606 
1607 			data_page = f2fs_get_read_data_page(inode, start_bidx,
1608 							REQ_RAHEAD, true, NULL);
1609 			f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1610 			if (IS_ERR(data_page)) {
1611 				iput(inode);
1612 				continue;
1613 			}
1614 
1615 			f2fs_put_page(data_page, 0);
1616 			add_gc_inode(gc_list, inode);
1617 			continue;
1618 		}
1619 
1620 		/* phase 4 */
1621 		inode = find_gc_inode(gc_list, dni.ino);
1622 		if (inode) {
1623 			struct f2fs_inode_info *fi = F2FS_I(inode);
1624 			bool locked = false;
1625 			int err;
1626 
1627 			if (S_ISREG(inode->i_mode)) {
1628 				if (!f2fs_down_write_trylock(&fi->i_gc_rwsem[WRITE])) {
1629 					sbi->skipped_gc_rwsem++;
1630 					continue;
1631 				}
1632 				if (!f2fs_down_write_trylock(
1633 						&fi->i_gc_rwsem[READ])) {
1634 					sbi->skipped_gc_rwsem++;
1635 					f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
1636 					continue;
1637 				}
1638 				locked = true;
1639 
1640 				/* wait for all inflight aio data */
1641 				inode_dio_wait(inode);
1642 			}
1643 
1644 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1645 								+ ofs_in_node;
1646 			if (f2fs_meta_inode_gc_required(inode))
1647 				err = move_data_block(inode, start_bidx,
1648 							gc_type, segno, off);
1649 			else
1650 				err = move_data_page(inode, start_bidx, gc_type,
1651 								segno, off);
1652 
1653 			if (!err && (gc_type == FG_GC ||
1654 					f2fs_meta_inode_gc_required(inode)))
1655 				submitted++;
1656 
1657 			if (locked) {
1658 				f2fs_up_write(&fi->i_gc_rwsem[READ]);
1659 				f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
1660 			}
1661 
1662 			stat_inc_data_blk_count(sbi, 1, gc_type);
1663 		}
1664 	}
1665 
1666 	if (++phase < 5)
1667 		goto next_step;
1668 
1669 	return submitted;
1670 }
1671 
1672 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1673 			int gc_type)
1674 {
1675 	struct sit_info *sit_i = SIT_I(sbi);
1676 	int ret;
1677 
1678 	down_write(&sit_i->sentry_lock);
1679 	ret = f2fs_get_victim(sbi, victim, gc_type, NO_CHECK_TYPE, LFS, 0);
1680 	up_write(&sit_i->sentry_lock);
1681 	return ret;
1682 }
1683 
1684 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1685 				unsigned int start_segno,
1686 				struct gc_inode_list *gc_list, int gc_type,
1687 				bool force_migrate)
1688 {
1689 	struct page *sum_page;
1690 	struct f2fs_summary_block *sum;
1691 	struct blk_plug plug;
1692 	unsigned int segno = start_segno;
1693 	unsigned int end_segno = start_segno + SEGS_PER_SEC(sbi);
1694 	int seg_freed = 0, migrated = 0;
1695 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1696 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1697 	unsigned char data_type = (type == SUM_TYPE_DATA) ? DATA : NODE;
1698 	int submitted = 0;
1699 
1700 	if (__is_large_section(sbi))
1701 		end_segno = rounddown(end_segno, SEGS_PER_SEC(sbi));
1702 
1703 	/*
1704 	 * zone-capacity can be less than zone-size in zoned devices,
1705 	 * resulting in less than expected usable segments in the zone,
1706 	 * calculate the end segno in the zone which can be garbage collected
1707 	 */
1708 	if (f2fs_sb_has_blkzoned(sbi))
1709 		end_segno -= SEGS_PER_SEC(sbi) -
1710 					f2fs_usable_segs_in_sec(sbi, segno);
1711 
1712 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
1713 
1714 	/* readahead multi ssa blocks those have contiguous address */
1715 	if (__is_large_section(sbi))
1716 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1717 					end_segno - segno, META_SSA, true);
1718 
1719 	/* reference all summary page */
1720 	while (segno < end_segno) {
1721 		sum_page = f2fs_get_sum_page(sbi, segno++);
1722 		if (IS_ERR(sum_page)) {
1723 			int err = PTR_ERR(sum_page);
1724 
1725 			end_segno = segno - 1;
1726 			for (segno = start_segno; segno < end_segno; segno++) {
1727 				sum_page = find_get_page(META_MAPPING(sbi),
1728 						GET_SUM_BLOCK(sbi, segno));
1729 				f2fs_put_page(sum_page, 0);
1730 				f2fs_put_page(sum_page, 0);
1731 			}
1732 			return err;
1733 		}
1734 		unlock_page(sum_page);
1735 	}
1736 
1737 	blk_start_plug(&plug);
1738 
1739 	for (segno = start_segno; segno < end_segno; segno++) {
1740 
1741 		/* find segment summary of victim */
1742 		sum_page = find_get_page(META_MAPPING(sbi),
1743 					GET_SUM_BLOCK(sbi, segno));
1744 		f2fs_put_page(sum_page, 0);
1745 
1746 		if (get_valid_blocks(sbi, segno, false) == 0)
1747 			goto freed;
1748 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1749 				migrated >= sbi->migration_granularity)
1750 			goto skip;
1751 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1752 			goto skip;
1753 
1754 		sum = page_address(sum_page);
1755 		if (type != GET_SUM_TYPE((&sum->footer))) {
1756 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1757 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1758 			f2fs_stop_checkpoint(sbi, false,
1759 				STOP_CP_REASON_CORRUPTED_SUMMARY);
1760 			goto skip;
1761 		}
1762 
1763 		/*
1764 		 * this is to avoid deadlock:
1765 		 * - lock_page(sum_page)         - f2fs_replace_block
1766 		 *  - check_valid_map()            - down_write(sentry_lock)
1767 		 *   - down_read(sentry_lock)     - change_curseg()
1768 		 *                                  - lock_page(sum_page)
1769 		 */
1770 		if (type == SUM_TYPE_NODE)
1771 			submitted += gc_node_segment(sbi, sum->entries, segno,
1772 								gc_type);
1773 		else
1774 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1775 							segno, gc_type,
1776 							force_migrate);
1777 
1778 		stat_inc_gc_seg_count(sbi, data_type, gc_type);
1779 		sbi->gc_reclaimed_segs[sbi->gc_mode]++;
1780 		migrated++;
1781 
1782 freed:
1783 		if (gc_type == FG_GC &&
1784 				get_valid_blocks(sbi, segno, false) == 0)
1785 			seg_freed++;
1786 
1787 		if (__is_large_section(sbi))
1788 			sbi->next_victim_seg[gc_type] =
1789 				(segno + 1 < end_segno) ? segno + 1 : NULL_SEGNO;
1790 skip:
1791 		f2fs_put_page(sum_page, 0);
1792 	}
1793 
1794 	if (submitted)
1795 		f2fs_submit_merged_write(sbi, data_type);
1796 
1797 	blk_finish_plug(&plug);
1798 
1799 	if (migrated)
1800 		stat_inc_gc_sec_count(sbi, data_type, gc_type);
1801 
1802 	return seg_freed;
1803 }
1804 
1805 int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
1806 {
1807 	int gc_type = gc_control->init_gc_type;
1808 	unsigned int segno = gc_control->victim_segno;
1809 	int sec_freed = 0, seg_freed = 0, total_freed = 0, total_sec_freed = 0;
1810 	int ret = 0;
1811 	struct cp_control cpc;
1812 	struct gc_inode_list gc_list = {
1813 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1814 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1815 	};
1816 	unsigned int skipped_round = 0, round = 0;
1817 	unsigned int upper_secs;
1818 
1819 	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
1820 				gc_control->nr_free_secs,
1821 				get_pages(sbi, F2FS_DIRTY_NODES),
1822 				get_pages(sbi, F2FS_DIRTY_DENTS),
1823 				get_pages(sbi, F2FS_DIRTY_IMETA),
1824 				free_sections(sbi),
1825 				free_segments(sbi),
1826 				reserved_segments(sbi),
1827 				prefree_segments(sbi));
1828 
1829 	cpc.reason = __get_cp_reason(sbi);
1830 gc_more:
1831 	sbi->skipped_gc_rwsem = 0;
1832 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1833 		ret = -EINVAL;
1834 		goto stop;
1835 	}
1836 	if (unlikely(f2fs_cp_error(sbi))) {
1837 		ret = -EIO;
1838 		goto stop;
1839 	}
1840 
1841 	/* Let's run FG_GC, if we don't have enough space. */
1842 	if (has_not_enough_free_secs(sbi, 0, 0)) {
1843 		gc_type = FG_GC;
1844 
1845 		/*
1846 		 * For example, if there are many prefree_segments below given
1847 		 * threshold, we can make them free by checkpoint. Then, we
1848 		 * secure free segments which doesn't need fggc any more.
1849 		 */
1850 		if (prefree_segments(sbi)) {
1851 			stat_inc_cp_call_count(sbi, TOTAL_CALL);
1852 			ret = f2fs_write_checkpoint(sbi, &cpc);
1853 			if (ret)
1854 				goto stop;
1855 			/* Reset due to checkpoint */
1856 			sec_freed = 0;
1857 		}
1858 	}
1859 
1860 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1861 	if (gc_type == BG_GC && gc_control->no_bg_gc) {
1862 		ret = -EINVAL;
1863 		goto stop;
1864 	}
1865 retry:
1866 	ret = __get_victim(sbi, &segno, gc_type);
1867 	if (ret) {
1868 		/* allow to search victim from sections has pinned data */
1869 		if (ret == -ENODATA && gc_type == FG_GC &&
1870 				f2fs_pinned_section_exists(DIRTY_I(sbi))) {
1871 			f2fs_unpin_all_sections(sbi, false);
1872 			goto retry;
1873 		}
1874 		goto stop;
1875 	}
1876 
1877 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type,
1878 				gc_control->should_migrate_blocks);
1879 	if (seg_freed < 0)
1880 		goto stop;
1881 
1882 	total_freed += seg_freed;
1883 
1884 	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno)) {
1885 		sec_freed++;
1886 		total_sec_freed++;
1887 	}
1888 
1889 	if (gc_type == FG_GC) {
1890 		sbi->cur_victim_sec = NULL_SEGNO;
1891 
1892 		if (has_enough_free_secs(sbi, sec_freed, 0)) {
1893 			if (!gc_control->no_bg_gc &&
1894 			    total_sec_freed < gc_control->nr_free_secs)
1895 				goto go_gc_more;
1896 			goto stop;
1897 		}
1898 		if (sbi->skipped_gc_rwsem)
1899 			skipped_round++;
1900 		round++;
1901 		if (skipped_round > MAX_SKIP_GC_COUNT &&
1902 				skipped_round * 2 >= round) {
1903 			stat_inc_cp_call_count(sbi, TOTAL_CALL);
1904 			ret = f2fs_write_checkpoint(sbi, &cpc);
1905 			goto stop;
1906 		}
1907 	} else if (has_enough_free_secs(sbi, 0, 0)) {
1908 		goto stop;
1909 	}
1910 
1911 	__get_secs_required(sbi, NULL, &upper_secs, NULL);
1912 
1913 	/*
1914 	 * Write checkpoint to reclaim prefree segments.
1915 	 * We need more three extra sections for writer's data/node/dentry.
1916 	 */
1917 	if (free_sections(sbi) <= upper_secs + NR_GC_CHECKPOINT_SECS &&
1918 				prefree_segments(sbi)) {
1919 		stat_inc_cp_call_count(sbi, TOTAL_CALL);
1920 		ret = f2fs_write_checkpoint(sbi, &cpc);
1921 		if (ret)
1922 			goto stop;
1923 		/* Reset due to checkpoint */
1924 		sec_freed = 0;
1925 	}
1926 go_gc_more:
1927 	segno = NULL_SEGNO;
1928 	goto gc_more;
1929 
1930 stop:
1931 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1932 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = gc_control->victim_segno;
1933 
1934 	if (gc_type == FG_GC)
1935 		f2fs_unpin_all_sections(sbi, true);
1936 
1937 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, total_sec_freed,
1938 				get_pages(sbi, F2FS_DIRTY_NODES),
1939 				get_pages(sbi, F2FS_DIRTY_DENTS),
1940 				get_pages(sbi, F2FS_DIRTY_IMETA),
1941 				free_sections(sbi),
1942 				free_segments(sbi),
1943 				reserved_segments(sbi),
1944 				prefree_segments(sbi));
1945 
1946 	f2fs_up_write(&sbi->gc_lock);
1947 
1948 	put_gc_inode(&gc_list);
1949 
1950 	if (gc_control->err_gc_skipped && !ret)
1951 		ret = total_sec_freed ? 0 : -EAGAIN;
1952 	return ret;
1953 }
1954 
1955 int __init f2fs_create_garbage_collection_cache(void)
1956 {
1957 	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
1958 					sizeof(struct victim_entry));
1959 	return victim_entry_slab ? 0 : -ENOMEM;
1960 }
1961 
1962 void f2fs_destroy_garbage_collection_cache(void)
1963 {
1964 	kmem_cache_destroy(victim_entry_slab);
1965 }
1966 
1967 static void init_atgc_management(struct f2fs_sb_info *sbi)
1968 {
1969 	struct atgc_management *am = &sbi->am;
1970 
1971 	if (test_opt(sbi, ATGC) &&
1972 		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
1973 		am->atgc_enabled = true;
1974 
1975 	am->root = RB_ROOT_CACHED;
1976 	INIT_LIST_HEAD(&am->victim_list);
1977 	am->victim_count = 0;
1978 
1979 	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
1980 	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
1981 	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
1982 	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
1983 }
1984 
1985 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1986 {
1987 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1988 
1989 	/* give warm/cold data area from slower device */
1990 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1991 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1992 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1993 
1994 	init_atgc_management(sbi);
1995 }
1996 
1997 int f2fs_gc_range(struct f2fs_sb_info *sbi,
1998 		unsigned int start_seg, unsigned int end_seg,
1999 		bool dry_run, unsigned int dry_run_sections)
2000 {
2001 	unsigned int segno;
2002 	unsigned int gc_secs = dry_run_sections;
2003 
2004 	if (unlikely(f2fs_cp_error(sbi)))
2005 		return -EIO;
2006 
2007 	for (segno = start_seg; segno <= end_seg; segno += SEGS_PER_SEC(sbi)) {
2008 		struct gc_inode_list gc_list = {
2009 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
2010 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
2011 		};
2012 
2013 		do_garbage_collect(sbi, segno, &gc_list, FG_GC,
2014 						dry_run_sections == 0);
2015 		put_gc_inode(&gc_list);
2016 
2017 		if (!dry_run && get_valid_blocks(sbi, segno, true))
2018 			return -EAGAIN;
2019 		if (dry_run && dry_run_sections &&
2020 		    !get_valid_blocks(sbi, segno, true) && --gc_secs == 0)
2021 			break;
2022 
2023 		if (fatal_signal_pending(current))
2024 			return -ERESTARTSYS;
2025 	}
2026 
2027 	return 0;
2028 }
2029 
2030 static int free_segment_range(struct f2fs_sb_info *sbi,
2031 				unsigned int secs, bool dry_run)
2032 {
2033 	unsigned int next_inuse, start, end;
2034 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
2035 	int gc_mode, gc_type;
2036 	int err = 0;
2037 	int type;
2038 
2039 	/* Force block allocation for GC */
2040 	MAIN_SECS(sbi) -= secs;
2041 	start = MAIN_SECS(sbi) * SEGS_PER_SEC(sbi);
2042 	end = MAIN_SEGS(sbi) - 1;
2043 
2044 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
2045 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
2046 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
2047 			SIT_I(sbi)->last_victim[gc_mode] = 0;
2048 
2049 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
2050 		if (sbi->next_victim_seg[gc_type] >= start)
2051 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
2052 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
2053 
2054 	/* Move out cursegs from the target range */
2055 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++) {
2056 		err = f2fs_allocate_segment_for_resize(sbi, type, start, end);
2057 		if (err)
2058 			goto out;
2059 	}
2060 
2061 	/* do GC to move out valid blocks in the range */
2062 	err = f2fs_gc_range(sbi, start, end, dry_run, 0);
2063 	if (err || dry_run)
2064 		goto out;
2065 
2066 	stat_inc_cp_call_count(sbi, TOTAL_CALL);
2067 	err = f2fs_write_checkpoint(sbi, &cpc);
2068 	if (err)
2069 		goto out;
2070 
2071 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
2072 	if (next_inuse <= end) {
2073 		f2fs_err(sbi, "segno %u should be free but still inuse!",
2074 			 next_inuse);
2075 		f2fs_bug_on(sbi, 1);
2076 	}
2077 out:
2078 	MAIN_SECS(sbi) += secs;
2079 	return err;
2080 }
2081 
2082 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
2083 {
2084 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
2085 	int section_count;
2086 	int segment_count;
2087 	int segment_count_main;
2088 	long long block_count;
2089 	int segs = secs * SEGS_PER_SEC(sbi);
2090 
2091 	f2fs_down_write(&sbi->sb_lock);
2092 
2093 	section_count = le32_to_cpu(raw_sb->section_count);
2094 	segment_count = le32_to_cpu(raw_sb->segment_count);
2095 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
2096 	block_count = le64_to_cpu(raw_sb->block_count);
2097 
2098 	raw_sb->section_count = cpu_to_le32(section_count + secs);
2099 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
2100 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
2101 	raw_sb->block_count = cpu_to_le64(block_count +
2102 			(long long)SEGS_TO_BLKS(sbi, segs));
2103 	if (f2fs_is_multi_device(sbi)) {
2104 		int last_dev = sbi->s_ndevs - 1;
2105 		int dev_segs =
2106 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
2107 
2108 		raw_sb->devs[last_dev].total_segments =
2109 						cpu_to_le32(dev_segs + segs);
2110 	}
2111 
2112 	f2fs_up_write(&sbi->sb_lock);
2113 }
2114 
2115 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
2116 {
2117 	int segs = secs * SEGS_PER_SEC(sbi);
2118 	long long blks = SEGS_TO_BLKS(sbi, segs);
2119 	long long user_block_count =
2120 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
2121 
2122 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
2123 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
2124 	MAIN_SECS(sbi) += secs;
2125 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
2126 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
2127 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
2128 
2129 	if (f2fs_is_multi_device(sbi)) {
2130 		int last_dev = sbi->s_ndevs - 1;
2131 
2132 		FDEV(last_dev).total_segments =
2133 				(int)FDEV(last_dev).total_segments + segs;
2134 		FDEV(last_dev).end_blk =
2135 				(long long)FDEV(last_dev).end_blk + blks;
2136 #ifdef CONFIG_BLK_DEV_ZONED
2137 		FDEV(last_dev).nr_blkz = FDEV(last_dev).nr_blkz +
2138 					div_u64(blks, sbi->blocks_per_blkz);
2139 #endif
2140 	}
2141 }
2142 
2143 int f2fs_resize_fs(struct file *filp, __u64 block_count)
2144 {
2145 	struct f2fs_sb_info *sbi = F2FS_I_SB(file_inode(filp));
2146 	__u64 old_block_count, shrunk_blocks;
2147 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
2148 	unsigned int secs;
2149 	int err = 0;
2150 	__u32 rem;
2151 
2152 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
2153 	if (block_count > old_block_count)
2154 		return -EINVAL;
2155 
2156 	if (f2fs_is_multi_device(sbi)) {
2157 		int last_dev = sbi->s_ndevs - 1;
2158 		__u64 last_segs = FDEV(last_dev).total_segments;
2159 
2160 		if (block_count + SEGS_TO_BLKS(sbi, last_segs) <=
2161 								old_block_count)
2162 			return -EINVAL;
2163 	}
2164 
2165 	/* new fs size should align to section size */
2166 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
2167 	if (rem)
2168 		return -EINVAL;
2169 
2170 	if (block_count == old_block_count)
2171 		return 0;
2172 
2173 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
2174 		f2fs_err(sbi, "Should run fsck to repair first.");
2175 		return -EFSCORRUPTED;
2176 	}
2177 
2178 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
2179 		f2fs_err(sbi, "Checkpoint should be enabled.");
2180 		return -EINVAL;
2181 	}
2182 
2183 	err = mnt_want_write_file(filp);
2184 	if (err)
2185 		return err;
2186 
2187 	shrunk_blocks = old_block_count - block_count;
2188 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
2189 
2190 	/* stop other GC */
2191 	if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
2192 		err = -EAGAIN;
2193 		goto out_drop_write;
2194 	}
2195 
2196 	/* stop CP to protect MAIN_SEC in free_segment_range */
2197 	f2fs_lock_op(sbi);
2198 
2199 	spin_lock(&sbi->stat_lock);
2200 	if (shrunk_blocks + valid_user_blocks(sbi) +
2201 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2202 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2203 		err = -ENOSPC;
2204 	spin_unlock(&sbi->stat_lock);
2205 
2206 	if (err)
2207 		goto out_unlock;
2208 
2209 	err = free_segment_range(sbi, secs, true);
2210 
2211 out_unlock:
2212 	f2fs_unlock_op(sbi);
2213 	f2fs_up_write(&sbi->gc_lock);
2214 out_drop_write:
2215 	mnt_drop_write_file(filp);
2216 	if (err)
2217 		return err;
2218 
2219 	err = freeze_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
2220 	if (err)
2221 		return err;
2222 
2223 	if (f2fs_readonly(sbi->sb)) {
2224 		err = thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
2225 		if (err)
2226 			return err;
2227 		return -EROFS;
2228 	}
2229 
2230 	f2fs_down_write(&sbi->gc_lock);
2231 	f2fs_down_write(&sbi->cp_global_sem);
2232 
2233 	spin_lock(&sbi->stat_lock);
2234 	if (shrunk_blocks + valid_user_blocks(sbi) +
2235 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2236 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2237 		err = -ENOSPC;
2238 	else
2239 		sbi->user_block_count -= shrunk_blocks;
2240 	spin_unlock(&sbi->stat_lock);
2241 	if (err)
2242 		goto out_err;
2243 
2244 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
2245 	err = free_segment_range(sbi, secs, false);
2246 	if (err)
2247 		goto recover_out;
2248 
2249 	update_sb_metadata(sbi, -secs);
2250 
2251 	err = f2fs_commit_super(sbi, false);
2252 	if (err) {
2253 		update_sb_metadata(sbi, secs);
2254 		goto recover_out;
2255 	}
2256 
2257 	update_fs_metadata(sbi, -secs);
2258 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2259 	set_sbi_flag(sbi, SBI_IS_DIRTY);
2260 
2261 	stat_inc_cp_call_count(sbi, TOTAL_CALL);
2262 	err = f2fs_write_checkpoint(sbi, &cpc);
2263 	if (err) {
2264 		update_fs_metadata(sbi, secs);
2265 		update_sb_metadata(sbi, secs);
2266 		f2fs_commit_super(sbi, false);
2267 	}
2268 recover_out:
2269 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2270 	if (err) {
2271 		set_sbi_flag(sbi, SBI_NEED_FSCK);
2272 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
2273 
2274 		spin_lock(&sbi->stat_lock);
2275 		sbi->user_block_count += shrunk_blocks;
2276 		spin_unlock(&sbi->stat_lock);
2277 	}
2278 out_err:
2279 	f2fs_up_write(&sbi->cp_global_sem);
2280 	f2fs_up_write(&sbi->gc_lock);
2281 	thaw_super(sbi->sb, FREEZE_HOLDER_USERSPACE);
2282 	return err;
2283 }
2284