xref: /linux/fs/f2fs/gc.c (revision 6863aaa88516292b885fdce5dd91925a00c3a3de)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * fs/f2fs/gc.c
4  *
5  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
6  *             http://www.samsung.com/
7  */
8 #include <linux/fs.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/f2fs_fs.h>
12 #include <linux/kthread.h>
13 #include <linux/delay.h>
14 #include <linux/freezer.h>
15 #include <linux/sched/signal.h>
16 #include <linux/random.h>
17 #include <linux/sched/mm.h>
18 
19 #include "f2fs.h"
20 #include "node.h"
21 #include "segment.h"
22 #include "gc.h"
23 #include "iostat.h"
24 #include <trace/events/f2fs.h>
25 
26 static struct kmem_cache *victim_entry_slab;
27 
28 static unsigned int count_bits(const unsigned long *addr,
29 				unsigned int offset, unsigned int len);
30 
31 static int gc_thread_func(void *data)
32 {
33 	struct f2fs_sb_info *sbi = data;
34 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
35 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
36 	wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
37 	unsigned int wait_ms;
38 	struct f2fs_gc_control gc_control = {
39 		.victim_segno = NULL_SEGNO,
40 		.should_migrate_blocks = false,
41 		.err_gc_skipped = false };
42 
43 	wait_ms = gc_th->min_sleep_time;
44 
45 	set_freezable();
46 	do {
47 		bool sync_mode, foreground = false;
48 
49 		wait_event_interruptible_timeout(*wq,
50 				kthread_should_stop() || freezing(current) ||
51 				waitqueue_active(fggc_wq) ||
52 				gc_th->gc_wake,
53 				msecs_to_jiffies(wait_ms));
54 
55 		if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
56 			foreground = true;
57 
58 		/* give it a try one time */
59 		if (gc_th->gc_wake)
60 			gc_th->gc_wake = 0;
61 
62 		if (try_to_freeze()) {
63 			stat_other_skip_bggc_count(sbi);
64 			continue;
65 		}
66 		if (kthread_should_stop())
67 			break;
68 
69 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
70 			increase_sleep_time(gc_th, &wait_ms);
71 			stat_other_skip_bggc_count(sbi);
72 			continue;
73 		}
74 
75 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
76 			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
77 			f2fs_stop_checkpoint(sbi, false,
78 					STOP_CP_REASON_FAULT_INJECT);
79 		}
80 
81 		if (!sb_start_write_trylock(sbi->sb)) {
82 			stat_other_skip_bggc_count(sbi);
83 			continue;
84 		}
85 
86 		/*
87 		 * [GC triggering condition]
88 		 * 0. GC is not conducted currently.
89 		 * 1. There are enough dirty segments.
90 		 * 2. IO subsystem is idle by checking the # of writeback pages.
91 		 * 3. IO subsystem is idle by checking the # of requests in
92 		 *    bdev's request list.
93 		 *
94 		 * Note) We have to avoid triggering GCs frequently.
95 		 * Because it is possible that some segments can be
96 		 * invalidated soon after by user update or deletion.
97 		 * So, I'd like to wait some time to collect dirty segments.
98 		 */
99 		if (sbi->gc_mode == GC_URGENT_HIGH) {
100 			spin_lock(&sbi->gc_urgent_high_lock);
101 			if (sbi->gc_urgent_high_remaining) {
102 				sbi->gc_urgent_high_remaining--;
103 				if (!sbi->gc_urgent_high_remaining)
104 					sbi->gc_mode = GC_NORMAL;
105 			}
106 			spin_unlock(&sbi->gc_urgent_high_lock);
107 		}
108 
109 		if (sbi->gc_mode == GC_URGENT_HIGH ||
110 				sbi->gc_mode == GC_URGENT_MID) {
111 			wait_ms = gc_th->urgent_sleep_time;
112 			f2fs_down_write(&sbi->gc_lock);
113 			goto do_gc;
114 		}
115 
116 		if (foreground) {
117 			f2fs_down_write(&sbi->gc_lock);
118 			goto do_gc;
119 		} else if (!f2fs_down_write_trylock(&sbi->gc_lock)) {
120 			stat_other_skip_bggc_count(sbi);
121 			goto next;
122 		}
123 
124 		if (!is_idle(sbi, GC_TIME)) {
125 			increase_sleep_time(gc_th, &wait_ms);
126 			f2fs_up_write(&sbi->gc_lock);
127 			stat_io_skip_bggc_count(sbi);
128 			goto next;
129 		}
130 
131 		if (has_enough_invalid_blocks(sbi))
132 			decrease_sleep_time(gc_th, &wait_ms);
133 		else
134 			increase_sleep_time(gc_th, &wait_ms);
135 do_gc:
136 		if (!foreground)
137 			stat_inc_bggc_count(sbi->stat_info);
138 
139 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
140 
141 		/* foreground GC was been triggered via f2fs_balance_fs() */
142 		if (foreground)
143 			sync_mode = false;
144 
145 		gc_control.init_gc_type = sync_mode ? FG_GC : BG_GC;
146 		gc_control.no_bg_gc = foreground;
147 		gc_control.nr_free_secs = foreground ? 1 : 0;
148 
149 		/* if return value is not zero, no victim was selected */
150 		if (f2fs_gc(sbi, &gc_control)) {
151 			/* don't bother wait_ms by foreground gc */
152 			if (!foreground)
153 				wait_ms = gc_th->no_gc_sleep_time;
154 		}
155 
156 		if (foreground)
157 			wake_up_all(&gc_th->fggc_wq);
158 
159 		trace_f2fs_background_gc(sbi->sb, wait_ms,
160 				prefree_segments(sbi), free_segments(sbi));
161 
162 		/* balancing f2fs's metadata periodically */
163 		f2fs_balance_fs_bg(sbi, true);
164 next:
165 		sb_end_write(sbi->sb);
166 
167 	} while (!kthread_should_stop());
168 	return 0;
169 }
170 
171 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
172 {
173 	struct f2fs_gc_kthread *gc_th;
174 	dev_t dev = sbi->sb->s_bdev->bd_dev;
175 	int err = 0;
176 
177 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
178 	if (!gc_th) {
179 		err = -ENOMEM;
180 		goto out;
181 	}
182 
183 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
184 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
185 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
186 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
187 
188 	gc_th->gc_wake = 0;
189 
190 	sbi->gc_thread = gc_th;
191 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
192 	init_waitqueue_head(&sbi->gc_thread->fggc_wq);
193 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
194 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
195 	if (IS_ERR(gc_th->f2fs_gc_task)) {
196 		err = PTR_ERR(gc_th->f2fs_gc_task);
197 		kfree(gc_th);
198 		sbi->gc_thread = NULL;
199 	}
200 out:
201 	return err;
202 }
203 
204 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
205 {
206 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
207 
208 	if (!gc_th)
209 		return;
210 	kthread_stop(gc_th->f2fs_gc_task);
211 	wake_up_all(&gc_th->fggc_wq);
212 	kfree(gc_th);
213 	sbi->gc_thread = NULL;
214 }
215 
216 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
217 {
218 	int gc_mode;
219 
220 	if (gc_type == BG_GC) {
221 		if (sbi->am.atgc_enabled)
222 			gc_mode = GC_AT;
223 		else
224 			gc_mode = GC_CB;
225 	} else {
226 		gc_mode = GC_GREEDY;
227 	}
228 
229 	switch (sbi->gc_mode) {
230 	case GC_IDLE_CB:
231 		gc_mode = GC_CB;
232 		break;
233 	case GC_IDLE_GREEDY:
234 	case GC_URGENT_HIGH:
235 		gc_mode = GC_GREEDY;
236 		break;
237 	case GC_IDLE_AT:
238 		gc_mode = GC_AT;
239 		break;
240 	}
241 
242 	return gc_mode;
243 }
244 
245 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
246 			int type, struct victim_sel_policy *p)
247 {
248 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
249 
250 	if (p->alloc_mode == SSR) {
251 		p->gc_mode = GC_GREEDY;
252 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
253 		p->max_search = dirty_i->nr_dirty[type];
254 		p->ofs_unit = 1;
255 	} else if (p->alloc_mode == AT_SSR) {
256 		p->gc_mode = GC_GREEDY;
257 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
258 		p->max_search = dirty_i->nr_dirty[type];
259 		p->ofs_unit = 1;
260 	} else {
261 		p->gc_mode = select_gc_type(sbi, gc_type);
262 		p->ofs_unit = sbi->segs_per_sec;
263 		if (__is_large_section(sbi)) {
264 			p->dirty_bitmap = dirty_i->dirty_secmap;
265 			p->max_search = count_bits(p->dirty_bitmap,
266 						0, MAIN_SECS(sbi));
267 		} else {
268 			p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
269 			p->max_search = dirty_i->nr_dirty[DIRTY];
270 		}
271 	}
272 
273 	/*
274 	 * adjust candidates range, should select all dirty segments for
275 	 * foreground GC and urgent GC cases.
276 	 */
277 	if (gc_type != FG_GC &&
278 			(sbi->gc_mode != GC_URGENT_HIGH) &&
279 			(p->gc_mode != GC_AT && p->alloc_mode != AT_SSR) &&
280 			p->max_search > sbi->max_victim_search)
281 		p->max_search = sbi->max_victim_search;
282 
283 	/* let's select beginning hot/small space first in no_heap mode*/
284 	if (f2fs_need_rand_seg(sbi))
285 		p->offset = prandom_u32_max(MAIN_SECS(sbi) * sbi->segs_per_sec);
286 	else if (test_opt(sbi, NOHEAP) &&
287 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
288 		p->offset = 0;
289 	else
290 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
291 }
292 
293 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
294 				struct victim_sel_policy *p)
295 {
296 	/* SSR allocates in a segment unit */
297 	if (p->alloc_mode == SSR)
298 		return sbi->blocks_per_seg;
299 	else if (p->alloc_mode == AT_SSR)
300 		return UINT_MAX;
301 
302 	/* LFS */
303 	if (p->gc_mode == GC_GREEDY)
304 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
305 	else if (p->gc_mode == GC_CB)
306 		return UINT_MAX;
307 	else if (p->gc_mode == GC_AT)
308 		return UINT_MAX;
309 	else /* No other gc_mode */
310 		return 0;
311 }
312 
313 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
314 {
315 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
316 	unsigned int secno;
317 
318 	/*
319 	 * If the gc_type is FG_GC, we can select victim segments
320 	 * selected by background GC before.
321 	 * Those segments guarantee they have small valid blocks.
322 	 */
323 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
324 		if (sec_usage_check(sbi, secno))
325 			continue;
326 		clear_bit(secno, dirty_i->victim_secmap);
327 		return GET_SEG_FROM_SEC(sbi, secno);
328 	}
329 	return NULL_SEGNO;
330 }
331 
332 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
333 {
334 	struct sit_info *sit_i = SIT_I(sbi);
335 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
336 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
337 	unsigned long long mtime = 0;
338 	unsigned int vblocks;
339 	unsigned char age = 0;
340 	unsigned char u;
341 	unsigned int i;
342 	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
343 
344 	for (i = 0; i < usable_segs_per_sec; i++)
345 		mtime += get_seg_entry(sbi, start + i)->mtime;
346 	vblocks = get_valid_blocks(sbi, segno, true);
347 
348 	mtime = div_u64(mtime, usable_segs_per_sec);
349 	vblocks = div_u64(vblocks, usable_segs_per_sec);
350 
351 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
352 
353 	/* Handle if the system time has changed by the user */
354 	if (mtime < sit_i->min_mtime)
355 		sit_i->min_mtime = mtime;
356 	if (mtime > sit_i->max_mtime)
357 		sit_i->max_mtime = mtime;
358 	if (sit_i->max_mtime != sit_i->min_mtime)
359 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
360 				sit_i->max_mtime - sit_i->min_mtime);
361 
362 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
363 }
364 
365 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
366 			unsigned int segno, struct victim_sel_policy *p)
367 {
368 	if (p->alloc_mode == SSR)
369 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
370 
371 	/* alloc_mode == LFS */
372 	if (p->gc_mode == GC_GREEDY)
373 		return get_valid_blocks(sbi, segno, true);
374 	else if (p->gc_mode == GC_CB)
375 		return get_cb_cost(sbi, segno);
376 
377 	f2fs_bug_on(sbi, 1);
378 	return 0;
379 }
380 
381 static unsigned int count_bits(const unsigned long *addr,
382 				unsigned int offset, unsigned int len)
383 {
384 	unsigned int end = offset + len, sum = 0;
385 
386 	while (offset < end) {
387 		if (test_bit(offset++, addr))
388 			++sum;
389 	}
390 	return sum;
391 }
392 
393 static struct victim_entry *attach_victim_entry(struct f2fs_sb_info *sbi,
394 				unsigned long long mtime, unsigned int segno,
395 				struct rb_node *parent, struct rb_node **p,
396 				bool left_most)
397 {
398 	struct atgc_management *am = &sbi->am;
399 	struct victim_entry *ve;
400 
401 	ve =  f2fs_kmem_cache_alloc(victim_entry_slab,
402 				GFP_NOFS, true, NULL);
403 
404 	ve->mtime = mtime;
405 	ve->segno = segno;
406 
407 	rb_link_node(&ve->rb_node, parent, p);
408 	rb_insert_color_cached(&ve->rb_node, &am->root, left_most);
409 
410 	list_add_tail(&ve->list, &am->victim_list);
411 
412 	am->victim_count++;
413 
414 	return ve;
415 }
416 
417 static void insert_victim_entry(struct f2fs_sb_info *sbi,
418 				unsigned long long mtime, unsigned int segno)
419 {
420 	struct atgc_management *am = &sbi->am;
421 	struct rb_node **p;
422 	struct rb_node *parent = NULL;
423 	bool left_most = true;
424 
425 	p = f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, mtime, &left_most);
426 	attach_victim_entry(sbi, mtime, segno, parent, p, left_most);
427 }
428 
429 static void add_victim_entry(struct f2fs_sb_info *sbi,
430 				struct victim_sel_policy *p, unsigned int segno)
431 {
432 	struct sit_info *sit_i = SIT_I(sbi);
433 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
434 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
435 	unsigned long long mtime = 0;
436 	unsigned int i;
437 
438 	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
439 		if (p->gc_mode == GC_AT &&
440 			get_valid_blocks(sbi, segno, true) == 0)
441 			return;
442 	}
443 
444 	for (i = 0; i < sbi->segs_per_sec; i++)
445 		mtime += get_seg_entry(sbi, start + i)->mtime;
446 	mtime = div_u64(mtime, sbi->segs_per_sec);
447 
448 	/* Handle if the system time has changed by the user */
449 	if (mtime < sit_i->min_mtime)
450 		sit_i->min_mtime = mtime;
451 	if (mtime > sit_i->max_mtime)
452 		sit_i->max_mtime = mtime;
453 	if (mtime < sit_i->dirty_min_mtime)
454 		sit_i->dirty_min_mtime = mtime;
455 	if (mtime > sit_i->dirty_max_mtime)
456 		sit_i->dirty_max_mtime = mtime;
457 
458 	/* don't choose young section as candidate */
459 	if (sit_i->dirty_max_mtime - mtime < p->age_threshold)
460 		return;
461 
462 	insert_victim_entry(sbi, mtime, segno);
463 }
464 
465 static struct rb_node *lookup_central_victim(struct f2fs_sb_info *sbi,
466 						struct victim_sel_policy *p)
467 {
468 	struct atgc_management *am = &sbi->am;
469 	struct rb_node *parent = NULL;
470 	bool left_most;
471 
472 	f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, p->age, &left_most);
473 
474 	return parent;
475 }
476 
477 static void atgc_lookup_victim(struct f2fs_sb_info *sbi,
478 						struct victim_sel_policy *p)
479 {
480 	struct sit_info *sit_i = SIT_I(sbi);
481 	struct atgc_management *am = &sbi->am;
482 	struct rb_root_cached *root = &am->root;
483 	struct rb_node *node;
484 	struct rb_entry *re;
485 	struct victim_entry *ve;
486 	unsigned long long total_time;
487 	unsigned long long age, u, accu;
488 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
489 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
490 	unsigned int sec_blocks = CAP_BLKS_PER_SEC(sbi);
491 	unsigned int vblocks;
492 	unsigned int dirty_threshold = max(am->max_candidate_count,
493 					am->candidate_ratio *
494 					am->victim_count / 100);
495 	unsigned int age_weight = am->age_weight;
496 	unsigned int cost;
497 	unsigned int iter = 0;
498 
499 	if (max_mtime < min_mtime)
500 		return;
501 
502 	max_mtime += 1;
503 	total_time = max_mtime - min_mtime;
504 
505 	accu = div64_u64(ULLONG_MAX, total_time);
506 	accu = min_t(unsigned long long, div_u64(accu, 100),
507 					DEFAULT_ACCURACY_CLASS);
508 
509 	node = rb_first_cached(root);
510 next:
511 	re = rb_entry_safe(node, struct rb_entry, rb_node);
512 	if (!re)
513 		return;
514 
515 	ve = (struct victim_entry *)re;
516 
517 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
518 		goto skip;
519 
520 	/* age = 10000 * x% * 60 */
521 	age = div64_u64(accu * (max_mtime - ve->mtime), total_time) *
522 								age_weight;
523 
524 	vblocks = get_valid_blocks(sbi, ve->segno, true);
525 	f2fs_bug_on(sbi, !vblocks || vblocks == sec_blocks);
526 
527 	/* u = 10000 * x% * 40 */
528 	u = div64_u64(accu * (sec_blocks - vblocks), sec_blocks) *
529 							(100 - age_weight);
530 
531 	f2fs_bug_on(sbi, age + u >= UINT_MAX);
532 
533 	cost = UINT_MAX - (age + u);
534 	iter++;
535 
536 	if (cost < p->min_cost ||
537 			(cost == p->min_cost && age > p->oldest_age)) {
538 		p->min_cost = cost;
539 		p->oldest_age = age;
540 		p->min_segno = ve->segno;
541 	}
542 skip:
543 	if (iter < dirty_threshold) {
544 		node = rb_next(node);
545 		goto next;
546 	}
547 }
548 
549 /*
550  * select candidates around source section in range of
551  * [target - dirty_threshold, target + dirty_threshold]
552  */
553 static void atssr_lookup_victim(struct f2fs_sb_info *sbi,
554 						struct victim_sel_policy *p)
555 {
556 	struct sit_info *sit_i = SIT_I(sbi);
557 	struct atgc_management *am = &sbi->am;
558 	struct rb_node *node;
559 	struct rb_entry *re;
560 	struct victim_entry *ve;
561 	unsigned long long age;
562 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
563 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
564 	unsigned int seg_blocks = sbi->blocks_per_seg;
565 	unsigned int vblocks;
566 	unsigned int dirty_threshold = max(am->max_candidate_count,
567 					am->candidate_ratio *
568 					am->victim_count / 100);
569 	unsigned int cost;
570 	unsigned int iter = 0;
571 	int stage = 0;
572 
573 	if (max_mtime < min_mtime)
574 		return;
575 	max_mtime += 1;
576 next_stage:
577 	node = lookup_central_victim(sbi, p);
578 next_node:
579 	re = rb_entry_safe(node, struct rb_entry, rb_node);
580 	if (!re) {
581 		if (stage == 0)
582 			goto skip_stage;
583 		return;
584 	}
585 
586 	ve = (struct victim_entry *)re;
587 
588 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
589 		goto skip_node;
590 
591 	age = max_mtime - ve->mtime;
592 
593 	vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
594 	f2fs_bug_on(sbi, !vblocks);
595 
596 	/* rare case */
597 	if (vblocks == seg_blocks)
598 		goto skip_node;
599 
600 	iter++;
601 
602 	age = max_mtime - abs(p->age - age);
603 	cost = UINT_MAX - vblocks;
604 
605 	if (cost < p->min_cost ||
606 			(cost == p->min_cost && age > p->oldest_age)) {
607 		p->min_cost = cost;
608 		p->oldest_age = age;
609 		p->min_segno = ve->segno;
610 	}
611 skip_node:
612 	if (iter < dirty_threshold) {
613 		if (stage == 0)
614 			node = rb_prev(node);
615 		else if (stage == 1)
616 			node = rb_next(node);
617 		goto next_node;
618 	}
619 skip_stage:
620 	if (stage < 1) {
621 		stage++;
622 		iter = 0;
623 		goto next_stage;
624 	}
625 }
626 static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
627 						struct victim_sel_policy *p)
628 {
629 	f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
630 						&sbi->am.root, true));
631 
632 	if (p->gc_mode == GC_AT)
633 		atgc_lookup_victim(sbi, p);
634 	else if (p->alloc_mode == AT_SSR)
635 		atssr_lookup_victim(sbi, p);
636 	else
637 		f2fs_bug_on(sbi, 1);
638 }
639 
640 static void release_victim_entry(struct f2fs_sb_info *sbi)
641 {
642 	struct atgc_management *am = &sbi->am;
643 	struct victim_entry *ve, *tmp;
644 
645 	list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
646 		list_del(&ve->list);
647 		kmem_cache_free(victim_entry_slab, ve);
648 		am->victim_count--;
649 	}
650 
651 	am->root = RB_ROOT_CACHED;
652 
653 	f2fs_bug_on(sbi, am->victim_count);
654 	f2fs_bug_on(sbi, !list_empty(&am->victim_list));
655 }
656 
657 static bool f2fs_pin_section(struct f2fs_sb_info *sbi, unsigned int segno)
658 {
659 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
660 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
661 
662 	if (!dirty_i->enable_pin_section)
663 		return false;
664 	if (!test_and_set_bit(secno, dirty_i->pinned_secmap))
665 		dirty_i->pinned_secmap_cnt++;
666 	return true;
667 }
668 
669 static bool f2fs_pinned_section_exists(struct dirty_seglist_info *dirty_i)
670 {
671 	return dirty_i->pinned_secmap_cnt;
672 }
673 
674 static bool f2fs_section_is_pinned(struct dirty_seglist_info *dirty_i,
675 						unsigned int secno)
676 {
677 	return dirty_i->enable_pin_section &&
678 		f2fs_pinned_section_exists(dirty_i) &&
679 		test_bit(secno, dirty_i->pinned_secmap);
680 }
681 
682 static void f2fs_unpin_all_sections(struct f2fs_sb_info *sbi, bool enable)
683 {
684 	unsigned int bitmap_size = f2fs_bitmap_size(MAIN_SECS(sbi));
685 
686 	if (f2fs_pinned_section_exists(DIRTY_I(sbi))) {
687 		memset(DIRTY_I(sbi)->pinned_secmap, 0, bitmap_size);
688 		DIRTY_I(sbi)->pinned_secmap_cnt = 0;
689 	}
690 	DIRTY_I(sbi)->enable_pin_section = enable;
691 }
692 
693 static int f2fs_gc_pinned_control(struct inode *inode, int gc_type,
694 							unsigned int segno)
695 {
696 	if (!f2fs_is_pinned_file(inode))
697 		return 0;
698 	if (gc_type != FG_GC)
699 		return -EBUSY;
700 	if (!f2fs_pin_section(F2FS_I_SB(inode), segno))
701 		f2fs_pin_file_control(inode, true);
702 	return -EAGAIN;
703 }
704 
705 /*
706  * This function is called from two paths.
707  * One is garbage collection and the other is SSR segment selection.
708  * When it is called during GC, it just gets a victim segment
709  * and it does not remove it from dirty seglist.
710  * When it is called from SSR segment selection, it finds a segment
711  * which has minimum valid blocks and removes it from dirty seglist.
712  */
713 static int get_victim_by_default(struct f2fs_sb_info *sbi,
714 			unsigned int *result, int gc_type, int type,
715 			char alloc_mode, unsigned long long age)
716 {
717 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
718 	struct sit_info *sm = SIT_I(sbi);
719 	struct victim_sel_policy p;
720 	unsigned int secno, last_victim;
721 	unsigned int last_segment;
722 	unsigned int nsearched;
723 	bool is_atgc;
724 	int ret = 0;
725 
726 	mutex_lock(&dirty_i->seglist_lock);
727 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
728 
729 	p.alloc_mode = alloc_mode;
730 	p.age = age;
731 	p.age_threshold = sbi->am.age_threshold;
732 
733 retry:
734 	select_policy(sbi, gc_type, type, &p);
735 	p.min_segno = NULL_SEGNO;
736 	p.oldest_age = 0;
737 	p.min_cost = get_max_cost(sbi, &p);
738 
739 	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
740 	nsearched = 0;
741 
742 	if (is_atgc)
743 		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
744 
745 	if (*result != NULL_SEGNO) {
746 		if (!get_valid_blocks(sbi, *result, false)) {
747 			ret = -ENODATA;
748 			goto out;
749 		}
750 
751 		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
752 			ret = -EBUSY;
753 		else
754 			p.min_segno = *result;
755 		goto out;
756 	}
757 
758 	ret = -ENODATA;
759 	if (p.max_search == 0)
760 		goto out;
761 
762 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
763 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
764 			p.min_segno = sbi->next_victim_seg[BG_GC];
765 			*result = p.min_segno;
766 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
767 			goto got_result;
768 		}
769 		if (gc_type == FG_GC &&
770 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
771 			p.min_segno = sbi->next_victim_seg[FG_GC];
772 			*result = p.min_segno;
773 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
774 			goto got_result;
775 		}
776 	}
777 
778 	last_victim = sm->last_victim[p.gc_mode];
779 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
780 		p.min_segno = check_bg_victims(sbi);
781 		if (p.min_segno != NULL_SEGNO)
782 			goto got_it;
783 	}
784 
785 	while (1) {
786 		unsigned long cost, *dirty_bitmap;
787 		unsigned int unit_no, segno;
788 
789 		dirty_bitmap = p.dirty_bitmap;
790 		unit_no = find_next_bit(dirty_bitmap,
791 				last_segment / p.ofs_unit,
792 				p.offset / p.ofs_unit);
793 		segno = unit_no * p.ofs_unit;
794 		if (segno >= last_segment) {
795 			if (sm->last_victim[p.gc_mode]) {
796 				last_segment =
797 					sm->last_victim[p.gc_mode];
798 				sm->last_victim[p.gc_mode] = 0;
799 				p.offset = 0;
800 				continue;
801 			}
802 			break;
803 		}
804 
805 		p.offset = segno + p.ofs_unit;
806 		nsearched++;
807 
808 #ifdef CONFIG_F2FS_CHECK_FS
809 		/*
810 		 * skip selecting the invalid segno (that is failed due to block
811 		 * validity check failure during GC) to avoid endless GC loop in
812 		 * such cases.
813 		 */
814 		if (test_bit(segno, sm->invalid_segmap))
815 			goto next;
816 #endif
817 
818 		secno = GET_SEC_FROM_SEG(sbi, segno);
819 
820 		if (sec_usage_check(sbi, secno))
821 			goto next;
822 
823 		/* Don't touch checkpointed data */
824 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
825 			if (p.alloc_mode == LFS) {
826 				/*
827 				 * LFS is set to find source section during GC.
828 				 * The victim should have no checkpointed data.
829 				 */
830 				if (get_ckpt_valid_blocks(sbi, segno, true))
831 					goto next;
832 			} else {
833 				/*
834 				 * SSR | AT_SSR are set to find target segment
835 				 * for writes which can be full by checkpointed
836 				 * and newly written blocks.
837 				 */
838 				if (!f2fs_segment_has_free_slot(sbi, segno))
839 					goto next;
840 			}
841 		}
842 
843 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
844 			goto next;
845 
846 		if (gc_type == FG_GC && f2fs_section_is_pinned(dirty_i, secno))
847 			goto next;
848 
849 		if (is_atgc) {
850 			add_victim_entry(sbi, &p, segno);
851 			goto next;
852 		}
853 
854 		cost = get_gc_cost(sbi, segno, &p);
855 
856 		if (p.min_cost > cost) {
857 			p.min_segno = segno;
858 			p.min_cost = cost;
859 		}
860 next:
861 		if (nsearched >= p.max_search) {
862 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
863 				sm->last_victim[p.gc_mode] =
864 					last_victim + p.ofs_unit;
865 			else
866 				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
867 			sm->last_victim[p.gc_mode] %=
868 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
869 			break;
870 		}
871 	}
872 
873 	/* get victim for GC_AT/AT_SSR */
874 	if (is_atgc) {
875 		lookup_victim_by_age(sbi, &p);
876 		release_victim_entry(sbi);
877 	}
878 
879 	if (is_atgc && p.min_segno == NULL_SEGNO &&
880 			sm->elapsed_time < p.age_threshold) {
881 		p.age_threshold = 0;
882 		goto retry;
883 	}
884 
885 	if (p.min_segno != NULL_SEGNO) {
886 got_it:
887 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
888 got_result:
889 		if (p.alloc_mode == LFS) {
890 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
891 			if (gc_type == FG_GC)
892 				sbi->cur_victim_sec = secno;
893 			else
894 				set_bit(secno, dirty_i->victim_secmap);
895 		}
896 		ret = 0;
897 
898 	}
899 out:
900 	if (p.min_segno != NULL_SEGNO)
901 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
902 				sbi->cur_victim_sec,
903 				prefree_segments(sbi), free_segments(sbi));
904 	mutex_unlock(&dirty_i->seglist_lock);
905 
906 	return ret;
907 }
908 
909 static const struct victim_selection default_v_ops = {
910 	.get_victim = get_victim_by_default,
911 };
912 
913 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
914 {
915 	struct inode_entry *ie;
916 
917 	ie = radix_tree_lookup(&gc_list->iroot, ino);
918 	if (ie)
919 		return ie->inode;
920 	return NULL;
921 }
922 
923 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
924 {
925 	struct inode_entry *new_ie;
926 
927 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
928 		iput(inode);
929 		return;
930 	}
931 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab,
932 					GFP_NOFS, true, NULL);
933 	new_ie->inode = inode;
934 
935 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
936 	list_add_tail(&new_ie->list, &gc_list->ilist);
937 }
938 
939 static void put_gc_inode(struct gc_inode_list *gc_list)
940 {
941 	struct inode_entry *ie, *next_ie;
942 
943 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
944 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
945 		iput(ie->inode);
946 		list_del(&ie->list);
947 		kmem_cache_free(f2fs_inode_entry_slab, ie);
948 	}
949 }
950 
951 static int check_valid_map(struct f2fs_sb_info *sbi,
952 				unsigned int segno, int offset)
953 {
954 	struct sit_info *sit_i = SIT_I(sbi);
955 	struct seg_entry *sentry;
956 	int ret;
957 
958 	down_read(&sit_i->sentry_lock);
959 	sentry = get_seg_entry(sbi, segno);
960 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
961 	up_read(&sit_i->sentry_lock);
962 	return ret;
963 }
964 
965 /*
966  * This function compares node address got in summary with that in NAT.
967  * On validity, copy that node with cold status, otherwise (invalid node)
968  * ignore that.
969  */
970 static int gc_node_segment(struct f2fs_sb_info *sbi,
971 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
972 {
973 	struct f2fs_summary *entry;
974 	block_t start_addr;
975 	int off;
976 	int phase = 0;
977 	bool fggc = (gc_type == FG_GC);
978 	int submitted = 0;
979 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
980 
981 	start_addr = START_BLOCK(sbi, segno);
982 
983 next_step:
984 	entry = sum;
985 
986 	if (fggc && phase == 2)
987 		atomic_inc(&sbi->wb_sync_req[NODE]);
988 
989 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
990 		nid_t nid = le32_to_cpu(entry->nid);
991 		struct page *node_page;
992 		struct node_info ni;
993 		int err;
994 
995 		/* stop BG_GC if there is not enough free sections. */
996 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
997 			return submitted;
998 
999 		if (check_valid_map(sbi, segno, off) == 0)
1000 			continue;
1001 
1002 		if (phase == 0) {
1003 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1004 							META_NAT, true);
1005 			continue;
1006 		}
1007 
1008 		if (phase == 1) {
1009 			f2fs_ra_node_page(sbi, nid);
1010 			continue;
1011 		}
1012 
1013 		/* phase == 2 */
1014 		node_page = f2fs_get_node_page(sbi, nid);
1015 		if (IS_ERR(node_page))
1016 			continue;
1017 
1018 		/* block may become invalid during f2fs_get_node_page */
1019 		if (check_valid_map(sbi, segno, off) == 0) {
1020 			f2fs_put_page(node_page, 1);
1021 			continue;
1022 		}
1023 
1024 		if (f2fs_get_node_info(sbi, nid, &ni, false)) {
1025 			f2fs_put_page(node_page, 1);
1026 			continue;
1027 		}
1028 
1029 		if (ni.blk_addr != start_addr + off) {
1030 			f2fs_put_page(node_page, 1);
1031 			continue;
1032 		}
1033 
1034 		err = f2fs_move_node_page(node_page, gc_type);
1035 		if (!err && gc_type == FG_GC)
1036 			submitted++;
1037 		stat_inc_node_blk_count(sbi, 1, gc_type);
1038 	}
1039 
1040 	if (++phase < 3)
1041 		goto next_step;
1042 
1043 	if (fggc)
1044 		atomic_dec(&sbi->wb_sync_req[NODE]);
1045 	return submitted;
1046 }
1047 
1048 /*
1049  * Calculate start block index indicating the given node offset.
1050  * Be careful, caller should give this node offset only indicating direct node
1051  * blocks. If any node offsets, which point the other types of node blocks such
1052  * as indirect or double indirect node blocks, are given, it must be a caller's
1053  * bug.
1054  */
1055 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
1056 {
1057 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
1058 	unsigned int bidx;
1059 
1060 	if (node_ofs == 0)
1061 		return 0;
1062 
1063 	if (node_ofs <= 2) {
1064 		bidx = node_ofs - 1;
1065 	} else if (node_ofs <= indirect_blks) {
1066 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
1067 
1068 		bidx = node_ofs - 2 - dec;
1069 	} else {
1070 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
1071 
1072 		bidx = node_ofs - 5 - dec;
1073 	}
1074 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
1075 }
1076 
1077 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1078 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
1079 {
1080 	struct page *node_page;
1081 	nid_t nid;
1082 	unsigned int ofs_in_node, max_addrs;
1083 	block_t source_blkaddr;
1084 
1085 	nid = le32_to_cpu(sum->nid);
1086 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
1087 
1088 	node_page = f2fs_get_node_page(sbi, nid);
1089 	if (IS_ERR(node_page))
1090 		return false;
1091 
1092 	if (f2fs_get_node_info(sbi, nid, dni, false)) {
1093 		f2fs_put_page(node_page, 1);
1094 		return false;
1095 	}
1096 
1097 	if (sum->version != dni->version) {
1098 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
1099 			  __func__);
1100 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1101 	}
1102 
1103 	if (f2fs_check_nid_range(sbi, dni->ino)) {
1104 		f2fs_put_page(node_page, 1);
1105 		return false;
1106 	}
1107 
1108 	max_addrs = IS_INODE(node_page) ? DEF_ADDRS_PER_INODE :
1109 						DEF_ADDRS_PER_BLOCK;
1110 	if (ofs_in_node >= max_addrs) {
1111 		f2fs_err(sbi, "Inconsistent ofs_in_node:%u in summary, ino:%u, nid:%u, max:%u",
1112 			ofs_in_node, dni->ino, dni->nid, max_addrs);
1113 		return false;
1114 	}
1115 
1116 	*nofs = ofs_of_node(node_page);
1117 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
1118 	f2fs_put_page(node_page, 1);
1119 
1120 	if (source_blkaddr != blkaddr) {
1121 #ifdef CONFIG_F2FS_CHECK_FS
1122 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
1123 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
1124 
1125 		if (unlikely(check_valid_map(sbi, segno, offset))) {
1126 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
1127 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u",
1128 					 blkaddr, source_blkaddr, segno);
1129 				set_sbi_flag(sbi, SBI_NEED_FSCK);
1130 			}
1131 		}
1132 #endif
1133 		return false;
1134 	}
1135 	return true;
1136 }
1137 
1138 static int ra_data_block(struct inode *inode, pgoff_t index)
1139 {
1140 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1141 	struct address_space *mapping = inode->i_mapping;
1142 	struct dnode_of_data dn;
1143 	struct page *page;
1144 	struct extent_info ei = {0, 0, 0};
1145 	struct f2fs_io_info fio = {
1146 		.sbi = sbi,
1147 		.ino = inode->i_ino,
1148 		.type = DATA,
1149 		.temp = COLD,
1150 		.op = REQ_OP_READ,
1151 		.op_flags = 0,
1152 		.encrypted_page = NULL,
1153 		.in_list = false,
1154 		.retry = false,
1155 	};
1156 	int err;
1157 
1158 	page = f2fs_grab_cache_page(mapping, index, true);
1159 	if (!page)
1160 		return -ENOMEM;
1161 
1162 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
1163 		dn.data_blkaddr = ei.blk + index - ei.fofs;
1164 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1165 						DATA_GENERIC_ENHANCE_READ))) {
1166 			err = -EFSCORRUPTED;
1167 			f2fs_handle_error(sbi, ERROR_INVALID_BLKADDR);
1168 			goto put_page;
1169 		}
1170 		goto got_it;
1171 	}
1172 
1173 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1174 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
1175 	if (err)
1176 		goto put_page;
1177 	f2fs_put_dnode(&dn);
1178 
1179 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
1180 		err = -ENOENT;
1181 		goto put_page;
1182 	}
1183 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1184 						DATA_GENERIC_ENHANCE))) {
1185 		err = -EFSCORRUPTED;
1186 		f2fs_handle_error(sbi, ERROR_INVALID_BLKADDR);
1187 		goto put_page;
1188 	}
1189 got_it:
1190 	/* read page */
1191 	fio.page = page;
1192 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1193 
1194 	/*
1195 	 * don't cache encrypted data into meta inode until previous dirty
1196 	 * data were writebacked to avoid racing between GC and flush.
1197 	 */
1198 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1199 
1200 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1201 
1202 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
1203 					dn.data_blkaddr,
1204 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
1205 	if (!fio.encrypted_page) {
1206 		err = -ENOMEM;
1207 		goto put_page;
1208 	}
1209 
1210 	err = f2fs_submit_page_bio(&fio);
1211 	if (err)
1212 		goto put_encrypted_page;
1213 	f2fs_put_page(fio.encrypted_page, 0);
1214 	f2fs_put_page(page, 1);
1215 
1216 	f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
1217 	f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1218 
1219 	return 0;
1220 put_encrypted_page:
1221 	f2fs_put_page(fio.encrypted_page, 1);
1222 put_page:
1223 	f2fs_put_page(page, 1);
1224 	return err;
1225 }
1226 
1227 /*
1228  * Move data block via META_MAPPING while keeping locked data page.
1229  * This can be used to move blocks, aka LBAs, directly on disk.
1230  */
1231 static int move_data_block(struct inode *inode, block_t bidx,
1232 				int gc_type, unsigned int segno, int off)
1233 {
1234 	struct f2fs_io_info fio = {
1235 		.sbi = F2FS_I_SB(inode),
1236 		.ino = inode->i_ino,
1237 		.type = DATA,
1238 		.temp = COLD,
1239 		.op = REQ_OP_READ,
1240 		.op_flags = 0,
1241 		.encrypted_page = NULL,
1242 		.in_list = false,
1243 		.retry = false,
1244 	};
1245 	struct dnode_of_data dn;
1246 	struct f2fs_summary sum;
1247 	struct node_info ni;
1248 	struct page *page, *mpage;
1249 	block_t newaddr;
1250 	int err = 0;
1251 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
1252 	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
1253 				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
1254 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
1255 
1256 	/* do not read out */
1257 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
1258 	if (!page)
1259 		return -ENOMEM;
1260 
1261 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1262 		err = -ENOENT;
1263 		goto out;
1264 	}
1265 
1266 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1267 	if (err)
1268 		goto out;
1269 
1270 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1271 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
1272 	if (err)
1273 		goto out;
1274 
1275 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
1276 		ClearPageUptodate(page);
1277 		err = -ENOENT;
1278 		goto put_out;
1279 	}
1280 
1281 	/*
1282 	 * don't cache encrypted data into meta inode until previous dirty
1283 	 * data were writebacked to avoid racing between GC and flush.
1284 	 */
1285 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1286 
1287 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1288 
1289 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni, false);
1290 	if (err)
1291 		goto put_out;
1292 
1293 	/* read page */
1294 	fio.page = page;
1295 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1296 
1297 	if (lfs_mode)
1298 		f2fs_down_write(&fio.sbi->io_order_lock);
1299 
1300 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
1301 					fio.old_blkaddr, false);
1302 	if (!mpage) {
1303 		err = -ENOMEM;
1304 		goto up_out;
1305 	}
1306 
1307 	fio.encrypted_page = mpage;
1308 
1309 	/* read source block in mpage */
1310 	if (!PageUptodate(mpage)) {
1311 		err = f2fs_submit_page_bio(&fio);
1312 		if (err) {
1313 			f2fs_put_page(mpage, 1);
1314 			goto up_out;
1315 		}
1316 
1317 		f2fs_update_iostat(fio.sbi, inode, FS_DATA_READ_IO,
1318 							F2FS_BLKSIZE);
1319 		f2fs_update_iostat(fio.sbi, NULL, FS_GDATA_READ_IO,
1320 							F2FS_BLKSIZE);
1321 
1322 		lock_page(mpage);
1323 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
1324 						!PageUptodate(mpage))) {
1325 			err = -EIO;
1326 			f2fs_put_page(mpage, 1);
1327 			goto up_out;
1328 		}
1329 	}
1330 
1331 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
1332 
1333 	/* allocate block address */
1334 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
1335 				&sum, type, NULL);
1336 
1337 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
1338 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
1339 	if (!fio.encrypted_page) {
1340 		err = -ENOMEM;
1341 		f2fs_put_page(mpage, 1);
1342 		goto recover_block;
1343 	}
1344 
1345 	/* write target block */
1346 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
1347 	memcpy(page_address(fio.encrypted_page),
1348 				page_address(mpage), PAGE_SIZE);
1349 	f2fs_put_page(mpage, 1);
1350 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
1351 				fio.old_blkaddr, fio.old_blkaddr);
1352 	f2fs_invalidate_compress_page(fio.sbi, fio.old_blkaddr);
1353 
1354 	set_page_dirty(fio.encrypted_page);
1355 	if (clear_page_dirty_for_io(fio.encrypted_page))
1356 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
1357 
1358 	set_page_writeback(fio.encrypted_page);
1359 	ClearPageError(page);
1360 
1361 	fio.op = REQ_OP_WRITE;
1362 	fio.op_flags = REQ_SYNC;
1363 	fio.new_blkaddr = newaddr;
1364 	f2fs_submit_page_write(&fio);
1365 	if (fio.retry) {
1366 		err = -EAGAIN;
1367 		if (PageWriteback(fio.encrypted_page))
1368 			end_page_writeback(fio.encrypted_page);
1369 		goto put_page_out;
1370 	}
1371 
1372 	f2fs_update_iostat(fio.sbi, NULL, FS_GC_DATA_IO, F2FS_BLKSIZE);
1373 
1374 	f2fs_update_data_blkaddr(&dn, newaddr);
1375 	set_inode_flag(inode, FI_APPEND_WRITE);
1376 	if (page->index == 0)
1377 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
1378 put_page_out:
1379 	f2fs_put_page(fio.encrypted_page, 1);
1380 recover_block:
1381 	if (err)
1382 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
1383 							true, true, true);
1384 up_out:
1385 	if (lfs_mode)
1386 		f2fs_up_write(&fio.sbi->io_order_lock);
1387 put_out:
1388 	f2fs_put_dnode(&dn);
1389 out:
1390 	f2fs_put_page(page, 1);
1391 	return err;
1392 }
1393 
1394 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
1395 							unsigned int segno, int off)
1396 {
1397 	struct page *page;
1398 	int err = 0;
1399 
1400 	page = f2fs_get_lock_data_page(inode, bidx, true);
1401 	if (IS_ERR(page))
1402 		return PTR_ERR(page);
1403 
1404 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1405 		err = -ENOENT;
1406 		goto out;
1407 	}
1408 
1409 	err = f2fs_gc_pinned_control(inode, gc_type, segno);
1410 	if (err)
1411 		goto out;
1412 
1413 	if (gc_type == BG_GC) {
1414 		if (PageWriteback(page)) {
1415 			err = -EAGAIN;
1416 			goto out;
1417 		}
1418 		set_page_dirty(page);
1419 		set_page_private_gcing(page);
1420 	} else {
1421 		struct f2fs_io_info fio = {
1422 			.sbi = F2FS_I_SB(inode),
1423 			.ino = inode->i_ino,
1424 			.type = DATA,
1425 			.temp = COLD,
1426 			.op = REQ_OP_WRITE,
1427 			.op_flags = REQ_SYNC,
1428 			.old_blkaddr = NULL_ADDR,
1429 			.page = page,
1430 			.encrypted_page = NULL,
1431 			.need_lock = LOCK_REQ,
1432 			.io_type = FS_GC_DATA_IO,
1433 		};
1434 		bool is_dirty = PageDirty(page);
1435 
1436 retry:
1437 		f2fs_wait_on_page_writeback(page, DATA, true, true);
1438 
1439 		set_page_dirty(page);
1440 		if (clear_page_dirty_for_io(page)) {
1441 			inode_dec_dirty_pages(inode);
1442 			f2fs_remove_dirty_inode(inode);
1443 		}
1444 
1445 		set_page_private_gcing(page);
1446 
1447 		err = f2fs_do_write_data_page(&fio);
1448 		if (err) {
1449 			clear_page_private_gcing(page);
1450 			if (err == -ENOMEM) {
1451 				memalloc_retry_wait(GFP_NOFS);
1452 				goto retry;
1453 			}
1454 			if (is_dirty)
1455 				set_page_dirty(page);
1456 		}
1457 	}
1458 out:
1459 	f2fs_put_page(page, 1);
1460 	return err;
1461 }
1462 
1463 /*
1464  * This function tries to get parent node of victim data block, and identifies
1465  * data block validity. If the block is valid, copy that with cold status and
1466  * modify parent node.
1467  * If the parent node is not valid or the data block address is different,
1468  * the victim data block is ignored.
1469  */
1470 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1471 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
1472 		bool force_migrate)
1473 {
1474 	struct super_block *sb = sbi->sb;
1475 	struct f2fs_summary *entry;
1476 	block_t start_addr;
1477 	int off;
1478 	int phase = 0;
1479 	int submitted = 0;
1480 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1481 
1482 	start_addr = START_BLOCK(sbi, segno);
1483 
1484 next_step:
1485 	entry = sum;
1486 
1487 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1488 		struct page *data_page;
1489 		struct inode *inode;
1490 		struct node_info dni; /* dnode info for the data */
1491 		unsigned int ofs_in_node, nofs;
1492 		block_t start_bidx;
1493 		nid_t nid = le32_to_cpu(entry->nid);
1494 
1495 		/*
1496 		 * stop BG_GC if there is not enough free sections.
1497 		 * Or, stop GC if the segment becomes fully valid caused by
1498 		 * race condition along with SSR block allocation.
1499 		 */
1500 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1501 			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
1502 							CAP_BLKS_PER_SEC(sbi)))
1503 			return submitted;
1504 
1505 		if (check_valid_map(sbi, segno, off) == 0)
1506 			continue;
1507 
1508 		if (phase == 0) {
1509 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1510 							META_NAT, true);
1511 			continue;
1512 		}
1513 
1514 		if (phase == 1) {
1515 			f2fs_ra_node_page(sbi, nid);
1516 			continue;
1517 		}
1518 
1519 		/* Get an inode by ino with checking validity */
1520 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1521 			continue;
1522 
1523 		if (phase == 2) {
1524 			f2fs_ra_node_page(sbi, dni.ino);
1525 			continue;
1526 		}
1527 
1528 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1529 
1530 		if (phase == 3) {
1531 			int err;
1532 
1533 			inode = f2fs_iget(sb, dni.ino);
1534 			if (IS_ERR(inode) || is_bad_inode(inode) ||
1535 					special_file(inode->i_mode))
1536 				continue;
1537 
1538 			err = f2fs_gc_pinned_control(inode, gc_type, segno);
1539 			if (err == -EAGAIN) {
1540 				iput(inode);
1541 				return submitted;
1542 			}
1543 
1544 			if (!f2fs_down_write_trylock(
1545 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1546 				iput(inode);
1547 				sbi->skipped_gc_rwsem++;
1548 				continue;
1549 			}
1550 
1551 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1552 								ofs_in_node;
1553 
1554 			if (f2fs_post_read_required(inode)) {
1555 				int err = ra_data_block(inode, start_bidx);
1556 
1557 				f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1558 				if (err) {
1559 					iput(inode);
1560 					continue;
1561 				}
1562 				add_gc_inode(gc_list, inode);
1563 				continue;
1564 			}
1565 
1566 			data_page = f2fs_get_read_data_page(inode,
1567 						start_bidx, REQ_RAHEAD, true);
1568 			f2fs_up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1569 			if (IS_ERR(data_page)) {
1570 				iput(inode);
1571 				continue;
1572 			}
1573 
1574 			f2fs_put_page(data_page, 0);
1575 			add_gc_inode(gc_list, inode);
1576 			continue;
1577 		}
1578 
1579 		/* phase 4 */
1580 		inode = find_gc_inode(gc_list, dni.ino);
1581 		if (inode) {
1582 			struct f2fs_inode_info *fi = F2FS_I(inode);
1583 			bool locked = false;
1584 			int err;
1585 
1586 			if (S_ISREG(inode->i_mode)) {
1587 				if (!f2fs_down_write_trylock(&fi->i_gc_rwsem[READ])) {
1588 					sbi->skipped_gc_rwsem++;
1589 					continue;
1590 				}
1591 				if (!f2fs_down_write_trylock(
1592 						&fi->i_gc_rwsem[WRITE])) {
1593 					sbi->skipped_gc_rwsem++;
1594 					f2fs_up_write(&fi->i_gc_rwsem[READ]);
1595 					continue;
1596 				}
1597 				locked = true;
1598 
1599 				/* wait for all inflight aio data */
1600 				inode_dio_wait(inode);
1601 			}
1602 
1603 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1604 								+ ofs_in_node;
1605 			if (f2fs_post_read_required(inode))
1606 				err = move_data_block(inode, start_bidx,
1607 							gc_type, segno, off);
1608 			else
1609 				err = move_data_page(inode, start_bidx, gc_type,
1610 								segno, off);
1611 
1612 			if (!err && (gc_type == FG_GC ||
1613 					f2fs_post_read_required(inode)))
1614 				submitted++;
1615 
1616 			if (locked) {
1617 				f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
1618 				f2fs_up_write(&fi->i_gc_rwsem[READ]);
1619 			}
1620 
1621 			stat_inc_data_blk_count(sbi, 1, gc_type);
1622 		}
1623 	}
1624 
1625 	if (++phase < 5)
1626 		goto next_step;
1627 
1628 	return submitted;
1629 }
1630 
1631 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1632 			int gc_type)
1633 {
1634 	struct sit_info *sit_i = SIT_I(sbi);
1635 	int ret;
1636 
1637 	down_write(&sit_i->sentry_lock);
1638 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1639 					      NO_CHECK_TYPE, LFS, 0);
1640 	up_write(&sit_i->sentry_lock);
1641 	return ret;
1642 }
1643 
1644 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1645 				unsigned int start_segno,
1646 				struct gc_inode_list *gc_list, int gc_type,
1647 				bool force_migrate)
1648 {
1649 	struct page *sum_page;
1650 	struct f2fs_summary_block *sum;
1651 	struct blk_plug plug;
1652 	unsigned int segno = start_segno;
1653 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1654 	int seg_freed = 0, migrated = 0;
1655 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1656 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1657 	int submitted = 0;
1658 
1659 	if (__is_large_section(sbi))
1660 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1661 
1662 	/*
1663 	 * zone-capacity can be less than zone-size in zoned devices,
1664 	 * resulting in less than expected usable segments in the zone,
1665 	 * calculate the end segno in the zone which can be garbage collected
1666 	 */
1667 	if (f2fs_sb_has_blkzoned(sbi))
1668 		end_segno -= sbi->segs_per_sec -
1669 					f2fs_usable_segs_in_sec(sbi, segno);
1670 
1671 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
1672 
1673 	/* readahead multi ssa blocks those have contiguous address */
1674 	if (__is_large_section(sbi))
1675 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1676 					end_segno - segno, META_SSA, true);
1677 
1678 	/* reference all summary page */
1679 	while (segno < end_segno) {
1680 		sum_page = f2fs_get_sum_page(sbi, segno++);
1681 		if (IS_ERR(sum_page)) {
1682 			int err = PTR_ERR(sum_page);
1683 
1684 			end_segno = segno - 1;
1685 			for (segno = start_segno; segno < end_segno; segno++) {
1686 				sum_page = find_get_page(META_MAPPING(sbi),
1687 						GET_SUM_BLOCK(sbi, segno));
1688 				f2fs_put_page(sum_page, 0);
1689 				f2fs_put_page(sum_page, 0);
1690 			}
1691 			return err;
1692 		}
1693 		unlock_page(sum_page);
1694 	}
1695 
1696 	blk_start_plug(&plug);
1697 
1698 	for (segno = start_segno; segno < end_segno; segno++) {
1699 
1700 		/* find segment summary of victim */
1701 		sum_page = find_get_page(META_MAPPING(sbi),
1702 					GET_SUM_BLOCK(sbi, segno));
1703 		f2fs_put_page(sum_page, 0);
1704 
1705 		if (get_valid_blocks(sbi, segno, false) == 0)
1706 			goto freed;
1707 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1708 				migrated >= sbi->migration_granularity)
1709 			goto skip;
1710 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1711 			goto skip;
1712 
1713 		sum = page_address(sum_page);
1714 		if (type != GET_SUM_TYPE((&sum->footer))) {
1715 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1716 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1717 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1718 			f2fs_stop_checkpoint(sbi, false,
1719 				STOP_CP_REASON_CORRUPTED_SUMMARY);
1720 			goto skip;
1721 		}
1722 
1723 		/*
1724 		 * this is to avoid deadlock:
1725 		 * - lock_page(sum_page)         - f2fs_replace_block
1726 		 *  - check_valid_map()            - down_write(sentry_lock)
1727 		 *   - down_read(sentry_lock)     - change_curseg()
1728 		 *                                  - lock_page(sum_page)
1729 		 */
1730 		if (type == SUM_TYPE_NODE)
1731 			submitted += gc_node_segment(sbi, sum->entries, segno,
1732 								gc_type);
1733 		else
1734 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1735 							segno, gc_type,
1736 							force_migrate);
1737 
1738 		stat_inc_seg_count(sbi, type, gc_type);
1739 		sbi->gc_reclaimed_segs[sbi->gc_mode]++;
1740 		migrated++;
1741 
1742 freed:
1743 		if (gc_type == FG_GC &&
1744 				get_valid_blocks(sbi, segno, false) == 0)
1745 			seg_freed++;
1746 
1747 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1748 			sbi->next_victim_seg[gc_type] = segno + 1;
1749 skip:
1750 		f2fs_put_page(sum_page, 0);
1751 	}
1752 
1753 	if (submitted)
1754 		f2fs_submit_merged_write(sbi,
1755 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1756 
1757 	blk_finish_plug(&plug);
1758 
1759 	stat_inc_call_count(sbi->stat_info);
1760 
1761 	return seg_freed;
1762 }
1763 
1764 int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
1765 {
1766 	int gc_type = gc_control->init_gc_type;
1767 	unsigned int segno = gc_control->victim_segno;
1768 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1769 	int ret = 0;
1770 	struct cp_control cpc;
1771 	struct gc_inode_list gc_list = {
1772 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1773 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1774 	};
1775 	unsigned int skipped_round = 0, round = 0;
1776 
1777 	trace_f2fs_gc_begin(sbi->sb, gc_type, gc_control->no_bg_gc,
1778 				gc_control->nr_free_secs,
1779 				get_pages(sbi, F2FS_DIRTY_NODES),
1780 				get_pages(sbi, F2FS_DIRTY_DENTS),
1781 				get_pages(sbi, F2FS_DIRTY_IMETA),
1782 				free_sections(sbi),
1783 				free_segments(sbi),
1784 				reserved_segments(sbi),
1785 				prefree_segments(sbi));
1786 
1787 	cpc.reason = __get_cp_reason(sbi);
1788 	sbi->skipped_gc_rwsem = 0;
1789 gc_more:
1790 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1791 		ret = -EINVAL;
1792 		goto stop;
1793 	}
1794 	if (unlikely(f2fs_cp_error(sbi))) {
1795 		ret = -EIO;
1796 		goto stop;
1797 	}
1798 
1799 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1800 		/*
1801 		 * For example, if there are many prefree_segments below given
1802 		 * threshold, we can make them free by checkpoint. Then, we
1803 		 * secure free segments which doesn't need fggc any more.
1804 		 */
1805 		if (prefree_segments(sbi)) {
1806 			ret = f2fs_write_checkpoint(sbi, &cpc);
1807 			if (ret)
1808 				goto stop;
1809 		}
1810 		if (has_not_enough_free_secs(sbi, 0, 0))
1811 			gc_type = FG_GC;
1812 	}
1813 
1814 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1815 	if (gc_type == BG_GC && gc_control->no_bg_gc) {
1816 		ret = -EINVAL;
1817 		goto stop;
1818 	}
1819 retry:
1820 	ret = __get_victim(sbi, &segno, gc_type);
1821 	if (ret) {
1822 		/* allow to search victim from sections has pinned data */
1823 		if (ret == -ENODATA && gc_type == FG_GC &&
1824 				f2fs_pinned_section_exists(DIRTY_I(sbi))) {
1825 			f2fs_unpin_all_sections(sbi, false);
1826 			goto retry;
1827 		}
1828 		goto stop;
1829 	}
1830 
1831 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type,
1832 				gc_control->should_migrate_blocks);
1833 	total_freed += seg_freed;
1834 
1835 	if (seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
1836 		sec_freed++;
1837 
1838 	if (gc_type == FG_GC)
1839 		sbi->cur_victim_sec = NULL_SEGNO;
1840 
1841 	if (gc_control->init_gc_type == FG_GC ||
1842 	    !has_not_enough_free_secs(sbi,
1843 				(gc_type == FG_GC) ? sec_freed : 0, 0)) {
1844 		if (gc_type == FG_GC && sec_freed < gc_control->nr_free_secs)
1845 			goto go_gc_more;
1846 		goto stop;
1847 	}
1848 
1849 	/* FG_GC stops GC by skip_count */
1850 	if (gc_type == FG_GC) {
1851 		if (sbi->skipped_gc_rwsem)
1852 			skipped_round++;
1853 		round++;
1854 		if (skipped_round > MAX_SKIP_GC_COUNT &&
1855 				skipped_round * 2 >= round) {
1856 			ret = f2fs_write_checkpoint(sbi, &cpc);
1857 			goto stop;
1858 		}
1859 	}
1860 
1861 	/* Write checkpoint to reclaim prefree segments */
1862 	if (free_sections(sbi) < NR_CURSEG_PERSIST_TYPE &&
1863 				prefree_segments(sbi)) {
1864 		ret = f2fs_write_checkpoint(sbi, &cpc);
1865 		if (ret)
1866 			goto stop;
1867 	}
1868 go_gc_more:
1869 	segno = NULL_SEGNO;
1870 	goto gc_more;
1871 
1872 stop:
1873 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1874 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = gc_control->victim_segno;
1875 
1876 	if (gc_type == FG_GC)
1877 		f2fs_unpin_all_sections(sbi, true);
1878 
1879 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1880 				get_pages(sbi, F2FS_DIRTY_NODES),
1881 				get_pages(sbi, F2FS_DIRTY_DENTS),
1882 				get_pages(sbi, F2FS_DIRTY_IMETA),
1883 				free_sections(sbi),
1884 				free_segments(sbi),
1885 				reserved_segments(sbi),
1886 				prefree_segments(sbi));
1887 
1888 	f2fs_up_write(&sbi->gc_lock);
1889 
1890 	put_gc_inode(&gc_list);
1891 
1892 	if (gc_control->err_gc_skipped && !ret)
1893 		ret = sec_freed ? 0 : -EAGAIN;
1894 	return ret;
1895 }
1896 
1897 int __init f2fs_create_garbage_collection_cache(void)
1898 {
1899 	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
1900 					sizeof(struct victim_entry));
1901 	if (!victim_entry_slab)
1902 		return -ENOMEM;
1903 	return 0;
1904 }
1905 
1906 void f2fs_destroy_garbage_collection_cache(void)
1907 {
1908 	kmem_cache_destroy(victim_entry_slab);
1909 }
1910 
1911 static void init_atgc_management(struct f2fs_sb_info *sbi)
1912 {
1913 	struct atgc_management *am = &sbi->am;
1914 
1915 	if (test_opt(sbi, ATGC) &&
1916 		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
1917 		am->atgc_enabled = true;
1918 
1919 	am->root = RB_ROOT_CACHED;
1920 	INIT_LIST_HEAD(&am->victim_list);
1921 	am->victim_count = 0;
1922 
1923 	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
1924 	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
1925 	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
1926 	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
1927 }
1928 
1929 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1930 {
1931 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1932 
1933 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1934 
1935 	/* give warm/cold data area from slower device */
1936 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1937 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1938 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1939 
1940 	init_atgc_management(sbi);
1941 }
1942 
1943 static int free_segment_range(struct f2fs_sb_info *sbi,
1944 				unsigned int secs, bool gc_only)
1945 {
1946 	unsigned int segno, next_inuse, start, end;
1947 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1948 	int gc_mode, gc_type;
1949 	int err = 0;
1950 	int type;
1951 
1952 	/* Force block allocation for GC */
1953 	MAIN_SECS(sbi) -= secs;
1954 	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
1955 	end = MAIN_SEGS(sbi) - 1;
1956 
1957 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1958 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1959 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
1960 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1961 
1962 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1963 		if (sbi->next_victim_seg[gc_type] >= start)
1964 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1965 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1966 
1967 	/* Move out cursegs from the target range */
1968 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++)
1969 		f2fs_allocate_segment_for_resize(sbi, type, start, end);
1970 
1971 	/* do GC to move out valid blocks in the range */
1972 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1973 		struct gc_inode_list gc_list = {
1974 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1975 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1976 		};
1977 
1978 		do_garbage_collect(sbi, segno, &gc_list, FG_GC, true);
1979 		put_gc_inode(&gc_list);
1980 
1981 		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
1982 			err = -EAGAIN;
1983 			goto out;
1984 		}
1985 		if (fatal_signal_pending(current)) {
1986 			err = -ERESTARTSYS;
1987 			goto out;
1988 		}
1989 	}
1990 	if (gc_only)
1991 		goto out;
1992 
1993 	err = f2fs_write_checkpoint(sbi, &cpc);
1994 	if (err)
1995 		goto out;
1996 
1997 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1998 	if (next_inuse <= end) {
1999 		f2fs_err(sbi, "segno %u should be free but still inuse!",
2000 			 next_inuse);
2001 		f2fs_bug_on(sbi, 1);
2002 	}
2003 out:
2004 	MAIN_SECS(sbi) += secs;
2005 	return err;
2006 }
2007 
2008 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
2009 {
2010 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
2011 	int section_count;
2012 	int segment_count;
2013 	int segment_count_main;
2014 	long long block_count;
2015 	int segs = secs * sbi->segs_per_sec;
2016 
2017 	f2fs_down_write(&sbi->sb_lock);
2018 
2019 	section_count = le32_to_cpu(raw_sb->section_count);
2020 	segment_count = le32_to_cpu(raw_sb->segment_count);
2021 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
2022 	block_count = le64_to_cpu(raw_sb->block_count);
2023 
2024 	raw_sb->section_count = cpu_to_le32(section_count + secs);
2025 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
2026 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
2027 	raw_sb->block_count = cpu_to_le64(block_count +
2028 					(long long)segs * sbi->blocks_per_seg);
2029 	if (f2fs_is_multi_device(sbi)) {
2030 		int last_dev = sbi->s_ndevs - 1;
2031 		int dev_segs =
2032 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
2033 
2034 		raw_sb->devs[last_dev].total_segments =
2035 						cpu_to_le32(dev_segs + segs);
2036 	}
2037 
2038 	f2fs_up_write(&sbi->sb_lock);
2039 }
2040 
2041 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
2042 {
2043 	int segs = secs * sbi->segs_per_sec;
2044 	long long blks = (long long)segs * sbi->blocks_per_seg;
2045 	long long user_block_count =
2046 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
2047 
2048 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
2049 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
2050 	MAIN_SECS(sbi) += secs;
2051 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
2052 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
2053 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
2054 
2055 	if (f2fs_is_multi_device(sbi)) {
2056 		int last_dev = sbi->s_ndevs - 1;
2057 
2058 		FDEV(last_dev).total_segments =
2059 				(int)FDEV(last_dev).total_segments + segs;
2060 		FDEV(last_dev).end_blk =
2061 				(long long)FDEV(last_dev).end_blk + blks;
2062 #ifdef CONFIG_BLK_DEV_ZONED
2063 		FDEV(last_dev).nr_blkz = (int)FDEV(last_dev).nr_blkz +
2064 					(int)(blks >> sbi->log_blocks_per_blkz);
2065 #endif
2066 	}
2067 }
2068 
2069 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
2070 {
2071 	__u64 old_block_count, shrunk_blocks;
2072 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
2073 	unsigned int secs;
2074 	int err = 0;
2075 	__u32 rem;
2076 
2077 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
2078 	if (block_count > old_block_count)
2079 		return -EINVAL;
2080 
2081 	if (f2fs_is_multi_device(sbi)) {
2082 		int last_dev = sbi->s_ndevs - 1;
2083 		__u64 last_segs = FDEV(last_dev).total_segments;
2084 
2085 		if (block_count + last_segs * sbi->blocks_per_seg <=
2086 								old_block_count)
2087 			return -EINVAL;
2088 	}
2089 
2090 	/* new fs size should align to section size */
2091 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
2092 	if (rem)
2093 		return -EINVAL;
2094 
2095 	if (block_count == old_block_count)
2096 		return 0;
2097 
2098 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
2099 		f2fs_err(sbi, "Should run fsck to repair first.");
2100 		return -EFSCORRUPTED;
2101 	}
2102 
2103 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
2104 		f2fs_err(sbi, "Checkpoint should be enabled.");
2105 		return -EINVAL;
2106 	}
2107 
2108 	shrunk_blocks = old_block_count - block_count;
2109 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
2110 
2111 	/* stop other GC */
2112 	if (!f2fs_down_write_trylock(&sbi->gc_lock))
2113 		return -EAGAIN;
2114 
2115 	/* stop CP to protect MAIN_SEC in free_segment_range */
2116 	f2fs_lock_op(sbi);
2117 
2118 	spin_lock(&sbi->stat_lock);
2119 	if (shrunk_blocks + valid_user_blocks(sbi) +
2120 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2121 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2122 		err = -ENOSPC;
2123 	spin_unlock(&sbi->stat_lock);
2124 
2125 	if (err)
2126 		goto out_unlock;
2127 
2128 	err = free_segment_range(sbi, secs, true);
2129 
2130 out_unlock:
2131 	f2fs_unlock_op(sbi);
2132 	f2fs_up_write(&sbi->gc_lock);
2133 	if (err)
2134 		return err;
2135 
2136 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
2137 
2138 	freeze_super(sbi->sb);
2139 	f2fs_down_write(&sbi->gc_lock);
2140 	f2fs_down_write(&sbi->cp_global_sem);
2141 
2142 	spin_lock(&sbi->stat_lock);
2143 	if (shrunk_blocks + valid_user_blocks(sbi) +
2144 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2145 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2146 		err = -ENOSPC;
2147 	else
2148 		sbi->user_block_count -= shrunk_blocks;
2149 	spin_unlock(&sbi->stat_lock);
2150 	if (err)
2151 		goto out_err;
2152 
2153 	err = free_segment_range(sbi, secs, false);
2154 	if (err)
2155 		goto recover_out;
2156 
2157 	update_sb_metadata(sbi, -secs);
2158 
2159 	err = f2fs_commit_super(sbi, false);
2160 	if (err) {
2161 		update_sb_metadata(sbi, secs);
2162 		goto recover_out;
2163 	}
2164 
2165 	update_fs_metadata(sbi, -secs);
2166 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2167 	set_sbi_flag(sbi, SBI_IS_DIRTY);
2168 
2169 	err = f2fs_write_checkpoint(sbi, &cpc);
2170 	if (err) {
2171 		update_fs_metadata(sbi, secs);
2172 		update_sb_metadata(sbi, secs);
2173 		f2fs_commit_super(sbi, false);
2174 	}
2175 recover_out:
2176 	if (err) {
2177 		set_sbi_flag(sbi, SBI_NEED_FSCK);
2178 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
2179 
2180 		spin_lock(&sbi->stat_lock);
2181 		sbi->user_block_count += shrunk_blocks;
2182 		spin_unlock(&sbi->stat_lock);
2183 	}
2184 out_err:
2185 	f2fs_up_write(&sbi->cp_global_sem);
2186 	f2fs_up_write(&sbi->gc_lock);
2187 	thaw_super(sbi->sb);
2188 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2189 	return err;
2190 }
2191