xref: /linux/fs/f2fs/gc.c (revision d4b996f9ef1fe83d9ce9ad5c1ca0bd8231638ce5)
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/backing-dev.h>
11 #include <linux/init.h>
12 #include <linux/f2fs_fs.h>
13 #include <linux/kthread.h>
14 #include <linux/delay.h>
15 #include <linux/freezer.h>
16 #include <linux/sched/signal.h>
17 
18 #include "f2fs.h"
19 #include "node.h"
20 #include "segment.h"
21 #include "gc.h"
22 #include <trace/events/f2fs.h>
23 
24 static struct kmem_cache *victim_entry_slab;
25 
26 static unsigned int count_bits(const unsigned long *addr,
27 				unsigned int offset, unsigned int len);
28 
29 static int gc_thread_func(void *data)
30 {
31 	struct f2fs_sb_info *sbi = data;
32 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
33 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
34 	wait_queue_head_t *fggc_wq = &sbi->gc_thread->fggc_wq;
35 	unsigned int wait_ms;
36 
37 	wait_ms = gc_th->min_sleep_time;
38 
39 	set_freezable();
40 	do {
41 		bool sync_mode, foreground = false;
42 
43 		wait_event_interruptible_timeout(*wq,
44 				kthread_should_stop() || freezing(current) ||
45 				waitqueue_active(fggc_wq) ||
46 				gc_th->gc_wake,
47 				msecs_to_jiffies(wait_ms));
48 
49 		if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
50 			foreground = true;
51 
52 		/* give it a try one time */
53 		if (gc_th->gc_wake)
54 			gc_th->gc_wake = 0;
55 
56 		if (try_to_freeze()) {
57 			stat_other_skip_bggc_count(sbi);
58 			continue;
59 		}
60 		if (kthread_should_stop())
61 			break;
62 
63 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
64 			increase_sleep_time(gc_th, &wait_ms);
65 			stat_other_skip_bggc_count(sbi);
66 			continue;
67 		}
68 
69 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
70 			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
71 			f2fs_stop_checkpoint(sbi, false);
72 		}
73 
74 		if (!sb_start_write_trylock(sbi->sb)) {
75 			stat_other_skip_bggc_count(sbi);
76 			continue;
77 		}
78 
79 		/*
80 		 * [GC triggering condition]
81 		 * 0. GC is not conducted currently.
82 		 * 1. There are enough dirty segments.
83 		 * 2. IO subsystem is idle by checking the # of writeback pages.
84 		 * 3. IO subsystem is idle by checking the # of requests in
85 		 *    bdev's request list.
86 		 *
87 		 * Note) We have to avoid triggering GCs frequently.
88 		 * Because it is possible that some segments can be
89 		 * invalidated soon after by user update or deletion.
90 		 * So, I'd like to wait some time to collect dirty segments.
91 		 */
92 		if (sbi->gc_mode == GC_URGENT_HIGH) {
93 			wait_ms = gc_th->urgent_sleep_time;
94 			down_write(&sbi->gc_lock);
95 			goto do_gc;
96 		}
97 
98 		if (foreground) {
99 			down_write(&sbi->gc_lock);
100 			goto do_gc;
101 		} else if (!down_write_trylock(&sbi->gc_lock)) {
102 			stat_other_skip_bggc_count(sbi);
103 			goto next;
104 		}
105 
106 		if (!is_idle(sbi, GC_TIME)) {
107 			increase_sleep_time(gc_th, &wait_ms);
108 			up_write(&sbi->gc_lock);
109 			stat_io_skip_bggc_count(sbi);
110 			goto next;
111 		}
112 
113 		if (has_enough_invalid_blocks(sbi))
114 			decrease_sleep_time(gc_th, &wait_ms);
115 		else
116 			increase_sleep_time(gc_th, &wait_ms);
117 do_gc:
118 		if (!foreground)
119 			stat_inc_bggc_count(sbi->stat_info);
120 
121 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
122 
123 		/* foreground GC was been triggered via f2fs_balance_fs() */
124 		if (foreground)
125 			sync_mode = false;
126 
127 		/* if return value is not zero, no victim was selected */
128 		if (f2fs_gc(sbi, sync_mode, !foreground, false, NULL_SEGNO))
129 			wait_ms = gc_th->no_gc_sleep_time;
130 
131 		if (foreground)
132 			wake_up_all(&gc_th->fggc_wq);
133 
134 		trace_f2fs_background_gc(sbi->sb, wait_ms,
135 				prefree_segments(sbi), free_segments(sbi));
136 
137 		/* balancing f2fs's metadata periodically */
138 		f2fs_balance_fs_bg(sbi, true);
139 next:
140 		sb_end_write(sbi->sb);
141 
142 	} while (!kthread_should_stop());
143 	return 0;
144 }
145 
146 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
147 {
148 	struct f2fs_gc_kthread *gc_th;
149 	dev_t dev = sbi->sb->s_bdev->bd_dev;
150 	int err = 0;
151 
152 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
153 	if (!gc_th) {
154 		err = -ENOMEM;
155 		goto out;
156 	}
157 
158 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
159 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
160 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
161 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
162 
163 	gc_th->gc_wake = 0;
164 
165 	sbi->gc_thread = gc_th;
166 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
167 	init_waitqueue_head(&sbi->gc_thread->fggc_wq);
168 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
169 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
170 	if (IS_ERR(gc_th->f2fs_gc_task)) {
171 		err = PTR_ERR(gc_th->f2fs_gc_task);
172 		kfree(gc_th);
173 		sbi->gc_thread = NULL;
174 	}
175 out:
176 	return err;
177 }
178 
179 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
180 {
181 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
182 
183 	if (!gc_th)
184 		return;
185 	kthread_stop(gc_th->f2fs_gc_task);
186 	wake_up_all(&gc_th->fggc_wq);
187 	kfree(gc_th);
188 	sbi->gc_thread = NULL;
189 }
190 
191 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
192 {
193 	int gc_mode;
194 
195 	if (gc_type == BG_GC) {
196 		if (sbi->am.atgc_enabled)
197 			gc_mode = GC_AT;
198 		else
199 			gc_mode = GC_CB;
200 	} else {
201 		gc_mode = GC_GREEDY;
202 	}
203 
204 	switch (sbi->gc_mode) {
205 	case GC_IDLE_CB:
206 		gc_mode = GC_CB;
207 		break;
208 	case GC_IDLE_GREEDY:
209 	case GC_URGENT_HIGH:
210 		gc_mode = GC_GREEDY;
211 		break;
212 	case GC_IDLE_AT:
213 		gc_mode = GC_AT;
214 		break;
215 	}
216 
217 	return gc_mode;
218 }
219 
220 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
221 			int type, struct victim_sel_policy *p)
222 {
223 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
224 
225 	if (p->alloc_mode == SSR) {
226 		p->gc_mode = GC_GREEDY;
227 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
228 		p->max_search = dirty_i->nr_dirty[type];
229 		p->ofs_unit = 1;
230 	} else if (p->alloc_mode == AT_SSR) {
231 		p->gc_mode = GC_GREEDY;
232 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
233 		p->max_search = dirty_i->nr_dirty[type];
234 		p->ofs_unit = 1;
235 	} else {
236 		p->gc_mode = select_gc_type(sbi, gc_type);
237 		p->ofs_unit = sbi->segs_per_sec;
238 		if (__is_large_section(sbi)) {
239 			p->dirty_bitmap = dirty_i->dirty_secmap;
240 			p->max_search = count_bits(p->dirty_bitmap,
241 						0, MAIN_SECS(sbi));
242 		} else {
243 			p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
244 			p->max_search = dirty_i->nr_dirty[DIRTY];
245 		}
246 	}
247 
248 	/*
249 	 * adjust candidates range, should select all dirty segments for
250 	 * foreground GC and urgent GC cases.
251 	 */
252 	if (gc_type != FG_GC &&
253 			(sbi->gc_mode != GC_URGENT_HIGH) &&
254 			(p->gc_mode != GC_AT && p->alloc_mode != AT_SSR) &&
255 			p->max_search > sbi->max_victim_search)
256 		p->max_search = sbi->max_victim_search;
257 
258 	/* let's select beginning hot/small space first in no_heap mode*/
259 	if (test_opt(sbi, NOHEAP) &&
260 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
261 		p->offset = 0;
262 	else
263 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
264 }
265 
266 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
267 				struct victim_sel_policy *p)
268 {
269 	/* SSR allocates in a segment unit */
270 	if (p->alloc_mode == SSR)
271 		return sbi->blocks_per_seg;
272 	else if (p->alloc_mode == AT_SSR)
273 		return UINT_MAX;
274 
275 	/* LFS */
276 	if (p->gc_mode == GC_GREEDY)
277 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
278 	else if (p->gc_mode == GC_CB)
279 		return UINT_MAX;
280 	else if (p->gc_mode == GC_AT)
281 		return UINT_MAX;
282 	else /* No other gc_mode */
283 		return 0;
284 }
285 
286 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
287 {
288 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
289 	unsigned int secno;
290 
291 	/*
292 	 * If the gc_type is FG_GC, we can select victim segments
293 	 * selected by background GC before.
294 	 * Those segments guarantee they have small valid blocks.
295 	 */
296 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
297 		if (sec_usage_check(sbi, secno))
298 			continue;
299 		clear_bit(secno, dirty_i->victim_secmap);
300 		return GET_SEG_FROM_SEC(sbi, secno);
301 	}
302 	return NULL_SEGNO;
303 }
304 
305 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
306 {
307 	struct sit_info *sit_i = SIT_I(sbi);
308 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
309 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
310 	unsigned long long mtime = 0;
311 	unsigned int vblocks;
312 	unsigned char age = 0;
313 	unsigned char u;
314 	unsigned int i;
315 	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
316 
317 	for (i = 0; i < usable_segs_per_sec; i++)
318 		mtime += get_seg_entry(sbi, start + i)->mtime;
319 	vblocks = get_valid_blocks(sbi, segno, true);
320 
321 	mtime = div_u64(mtime, usable_segs_per_sec);
322 	vblocks = div_u64(vblocks, usable_segs_per_sec);
323 
324 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
325 
326 	/* Handle if the system time has changed by the user */
327 	if (mtime < sit_i->min_mtime)
328 		sit_i->min_mtime = mtime;
329 	if (mtime > sit_i->max_mtime)
330 		sit_i->max_mtime = mtime;
331 	if (sit_i->max_mtime != sit_i->min_mtime)
332 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
333 				sit_i->max_mtime - sit_i->min_mtime);
334 
335 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
336 }
337 
338 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
339 			unsigned int segno, struct victim_sel_policy *p)
340 {
341 	if (p->alloc_mode == SSR)
342 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
343 
344 	/* alloc_mode == LFS */
345 	if (p->gc_mode == GC_GREEDY)
346 		return get_valid_blocks(sbi, segno, true);
347 	else if (p->gc_mode == GC_CB)
348 		return get_cb_cost(sbi, segno);
349 
350 	f2fs_bug_on(sbi, 1);
351 	return 0;
352 }
353 
354 static unsigned int count_bits(const unsigned long *addr,
355 				unsigned int offset, unsigned int len)
356 {
357 	unsigned int end = offset + len, sum = 0;
358 
359 	while (offset < end) {
360 		if (test_bit(offset++, addr))
361 			++sum;
362 	}
363 	return sum;
364 }
365 
366 static struct victim_entry *attach_victim_entry(struct f2fs_sb_info *sbi,
367 				unsigned long long mtime, unsigned int segno,
368 				struct rb_node *parent, struct rb_node **p,
369 				bool left_most)
370 {
371 	struct atgc_management *am = &sbi->am;
372 	struct victim_entry *ve;
373 
374 	ve =  f2fs_kmem_cache_alloc(victim_entry_slab, GFP_NOFS);
375 
376 	ve->mtime = mtime;
377 	ve->segno = segno;
378 
379 	rb_link_node(&ve->rb_node, parent, p);
380 	rb_insert_color_cached(&ve->rb_node, &am->root, left_most);
381 
382 	list_add_tail(&ve->list, &am->victim_list);
383 
384 	am->victim_count++;
385 
386 	return ve;
387 }
388 
389 static void insert_victim_entry(struct f2fs_sb_info *sbi,
390 				unsigned long long mtime, unsigned int segno)
391 {
392 	struct atgc_management *am = &sbi->am;
393 	struct rb_node **p;
394 	struct rb_node *parent = NULL;
395 	bool left_most = true;
396 
397 	p = f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, mtime, &left_most);
398 	attach_victim_entry(sbi, mtime, segno, parent, p, left_most);
399 }
400 
401 static void add_victim_entry(struct f2fs_sb_info *sbi,
402 				struct victim_sel_policy *p, unsigned int segno)
403 {
404 	struct sit_info *sit_i = SIT_I(sbi);
405 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
406 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
407 	unsigned long long mtime = 0;
408 	unsigned int i;
409 
410 	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
411 		if (p->gc_mode == GC_AT &&
412 			get_valid_blocks(sbi, segno, true) == 0)
413 			return;
414 	}
415 
416 	for (i = 0; i < sbi->segs_per_sec; i++)
417 		mtime += get_seg_entry(sbi, start + i)->mtime;
418 	mtime = div_u64(mtime, sbi->segs_per_sec);
419 
420 	/* Handle if the system time has changed by the user */
421 	if (mtime < sit_i->min_mtime)
422 		sit_i->min_mtime = mtime;
423 	if (mtime > sit_i->max_mtime)
424 		sit_i->max_mtime = mtime;
425 	if (mtime < sit_i->dirty_min_mtime)
426 		sit_i->dirty_min_mtime = mtime;
427 	if (mtime > sit_i->dirty_max_mtime)
428 		sit_i->dirty_max_mtime = mtime;
429 
430 	/* don't choose young section as candidate */
431 	if (sit_i->dirty_max_mtime - mtime < p->age_threshold)
432 		return;
433 
434 	insert_victim_entry(sbi, mtime, segno);
435 }
436 
437 static struct rb_node *lookup_central_victim(struct f2fs_sb_info *sbi,
438 						struct victim_sel_policy *p)
439 {
440 	struct atgc_management *am = &sbi->am;
441 	struct rb_node *parent = NULL;
442 	bool left_most;
443 
444 	f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, p->age, &left_most);
445 
446 	return parent;
447 }
448 
449 static void atgc_lookup_victim(struct f2fs_sb_info *sbi,
450 						struct victim_sel_policy *p)
451 {
452 	struct sit_info *sit_i = SIT_I(sbi);
453 	struct atgc_management *am = &sbi->am;
454 	struct rb_root_cached *root = &am->root;
455 	struct rb_node *node;
456 	struct rb_entry *re;
457 	struct victim_entry *ve;
458 	unsigned long long total_time;
459 	unsigned long long age, u, accu;
460 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
461 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
462 	unsigned int sec_blocks = BLKS_PER_SEC(sbi);
463 	unsigned int vblocks;
464 	unsigned int dirty_threshold = max(am->max_candidate_count,
465 					am->candidate_ratio *
466 					am->victim_count / 100);
467 	unsigned int age_weight = am->age_weight;
468 	unsigned int cost;
469 	unsigned int iter = 0;
470 
471 	if (max_mtime < min_mtime)
472 		return;
473 
474 	max_mtime += 1;
475 	total_time = max_mtime - min_mtime;
476 
477 	accu = div64_u64(ULLONG_MAX, total_time);
478 	accu = min_t(unsigned long long, div_u64(accu, 100),
479 					DEFAULT_ACCURACY_CLASS);
480 
481 	node = rb_first_cached(root);
482 next:
483 	re = rb_entry_safe(node, struct rb_entry, rb_node);
484 	if (!re)
485 		return;
486 
487 	ve = (struct victim_entry *)re;
488 
489 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
490 		goto skip;
491 
492 	/* age = 10000 * x% * 60 */
493 	age = div64_u64(accu * (max_mtime - ve->mtime), total_time) *
494 								age_weight;
495 
496 	vblocks = get_valid_blocks(sbi, ve->segno, true);
497 	f2fs_bug_on(sbi, !vblocks || vblocks == sec_blocks);
498 
499 	/* u = 10000 * x% * 40 */
500 	u = div64_u64(accu * (sec_blocks - vblocks), sec_blocks) *
501 							(100 - age_weight);
502 
503 	f2fs_bug_on(sbi, age + u >= UINT_MAX);
504 
505 	cost = UINT_MAX - (age + u);
506 	iter++;
507 
508 	if (cost < p->min_cost ||
509 			(cost == p->min_cost && age > p->oldest_age)) {
510 		p->min_cost = cost;
511 		p->oldest_age = age;
512 		p->min_segno = ve->segno;
513 	}
514 skip:
515 	if (iter < dirty_threshold) {
516 		node = rb_next(node);
517 		goto next;
518 	}
519 }
520 
521 /*
522  * select candidates around source section in range of
523  * [target - dirty_threshold, target + dirty_threshold]
524  */
525 static void atssr_lookup_victim(struct f2fs_sb_info *sbi,
526 						struct victim_sel_policy *p)
527 {
528 	struct sit_info *sit_i = SIT_I(sbi);
529 	struct atgc_management *am = &sbi->am;
530 	struct rb_node *node;
531 	struct rb_entry *re;
532 	struct victim_entry *ve;
533 	unsigned long long age;
534 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
535 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
536 	unsigned int seg_blocks = sbi->blocks_per_seg;
537 	unsigned int vblocks;
538 	unsigned int dirty_threshold = max(am->max_candidate_count,
539 					am->candidate_ratio *
540 					am->victim_count / 100);
541 	unsigned int cost;
542 	unsigned int iter = 0;
543 	int stage = 0;
544 
545 	if (max_mtime < min_mtime)
546 		return;
547 	max_mtime += 1;
548 next_stage:
549 	node = lookup_central_victim(sbi, p);
550 next_node:
551 	re = rb_entry_safe(node, struct rb_entry, rb_node);
552 	if (!re) {
553 		if (stage == 0)
554 			goto skip_stage;
555 		return;
556 	}
557 
558 	ve = (struct victim_entry *)re;
559 
560 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
561 		goto skip_node;
562 
563 	age = max_mtime - ve->mtime;
564 
565 	vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
566 	f2fs_bug_on(sbi, !vblocks);
567 
568 	/* rare case */
569 	if (vblocks == seg_blocks)
570 		goto skip_node;
571 
572 	iter++;
573 
574 	age = max_mtime - abs(p->age - age);
575 	cost = UINT_MAX - vblocks;
576 
577 	if (cost < p->min_cost ||
578 			(cost == p->min_cost && age > p->oldest_age)) {
579 		p->min_cost = cost;
580 		p->oldest_age = age;
581 		p->min_segno = ve->segno;
582 	}
583 skip_node:
584 	if (iter < dirty_threshold) {
585 		if (stage == 0)
586 			node = rb_prev(node);
587 		else if (stage == 1)
588 			node = rb_next(node);
589 		goto next_node;
590 	}
591 skip_stage:
592 	if (stage < 1) {
593 		stage++;
594 		iter = 0;
595 		goto next_stage;
596 	}
597 }
598 static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
599 						struct victim_sel_policy *p)
600 {
601 	f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
602 						&sbi->am.root, true));
603 
604 	if (p->gc_mode == GC_AT)
605 		atgc_lookup_victim(sbi, p);
606 	else if (p->alloc_mode == AT_SSR)
607 		atssr_lookup_victim(sbi, p);
608 	else
609 		f2fs_bug_on(sbi, 1);
610 }
611 
612 static void release_victim_entry(struct f2fs_sb_info *sbi)
613 {
614 	struct atgc_management *am = &sbi->am;
615 	struct victim_entry *ve, *tmp;
616 
617 	list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
618 		list_del(&ve->list);
619 		kmem_cache_free(victim_entry_slab, ve);
620 		am->victim_count--;
621 	}
622 
623 	am->root = RB_ROOT_CACHED;
624 
625 	f2fs_bug_on(sbi, am->victim_count);
626 	f2fs_bug_on(sbi, !list_empty(&am->victim_list));
627 }
628 
629 /*
630  * This function is called from two paths.
631  * One is garbage collection and the other is SSR segment selection.
632  * When it is called during GC, it just gets a victim segment
633  * and it does not remove it from dirty seglist.
634  * When it is called from SSR segment selection, it finds a segment
635  * which has minimum valid blocks and removes it from dirty seglist.
636  */
637 static int get_victim_by_default(struct f2fs_sb_info *sbi,
638 			unsigned int *result, int gc_type, int type,
639 			char alloc_mode, unsigned long long age)
640 {
641 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
642 	struct sit_info *sm = SIT_I(sbi);
643 	struct victim_sel_policy p;
644 	unsigned int secno, last_victim;
645 	unsigned int last_segment;
646 	unsigned int nsearched;
647 	bool is_atgc;
648 	int ret = 0;
649 
650 	mutex_lock(&dirty_i->seglist_lock);
651 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
652 
653 	p.alloc_mode = alloc_mode;
654 	p.age = age;
655 	p.age_threshold = sbi->am.age_threshold;
656 
657 retry:
658 	select_policy(sbi, gc_type, type, &p);
659 	p.min_segno = NULL_SEGNO;
660 	p.oldest_age = 0;
661 	p.min_cost = get_max_cost(sbi, &p);
662 
663 	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
664 	nsearched = 0;
665 
666 	if (is_atgc)
667 		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
668 
669 	if (*result != NULL_SEGNO) {
670 		if (!get_valid_blocks(sbi, *result, false)) {
671 			ret = -ENODATA;
672 			goto out;
673 		}
674 
675 		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
676 			ret = -EBUSY;
677 		else
678 			p.min_segno = *result;
679 		goto out;
680 	}
681 
682 	ret = -ENODATA;
683 	if (p.max_search == 0)
684 		goto out;
685 
686 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
687 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
688 			p.min_segno = sbi->next_victim_seg[BG_GC];
689 			*result = p.min_segno;
690 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
691 			goto got_result;
692 		}
693 		if (gc_type == FG_GC &&
694 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
695 			p.min_segno = sbi->next_victim_seg[FG_GC];
696 			*result = p.min_segno;
697 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
698 			goto got_result;
699 		}
700 	}
701 
702 	last_victim = sm->last_victim[p.gc_mode];
703 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
704 		p.min_segno = check_bg_victims(sbi);
705 		if (p.min_segno != NULL_SEGNO)
706 			goto got_it;
707 	}
708 
709 	while (1) {
710 		unsigned long cost, *dirty_bitmap;
711 		unsigned int unit_no, segno;
712 
713 		dirty_bitmap = p.dirty_bitmap;
714 		unit_no = find_next_bit(dirty_bitmap,
715 				last_segment / p.ofs_unit,
716 				p.offset / p.ofs_unit);
717 		segno = unit_no * p.ofs_unit;
718 		if (segno >= last_segment) {
719 			if (sm->last_victim[p.gc_mode]) {
720 				last_segment =
721 					sm->last_victim[p.gc_mode];
722 				sm->last_victim[p.gc_mode] = 0;
723 				p.offset = 0;
724 				continue;
725 			}
726 			break;
727 		}
728 
729 		p.offset = segno + p.ofs_unit;
730 		nsearched++;
731 
732 #ifdef CONFIG_F2FS_CHECK_FS
733 		/*
734 		 * skip selecting the invalid segno (that is failed due to block
735 		 * validity check failure during GC) to avoid endless GC loop in
736 		 * such cases.
737 		 */
738 		if (test_bit(segno, sm->invalid_segmap))
739 			goto next;
740 #endif
741 
742 		secno = GET_SEC_FROM_SEG(sbi, segno);
743 
744 		if (sec_usage_check(sbi, secno))
745 			goto next;
746 
747 		/* Don't touch checkpointed data */
748 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
749 			if (p.alloc_mode == LFS) {
750 				/*
751 				 * LFS is set to find source section during GC.
752 				 * The victim should have no checkpointed data.
753 				 */
754 				if (get_ckpt_valid_blocks(sbi, segno, true))
755 					goto next;
756 			} else {
757 				/*
758 				 * SSR | AT_SSR are set to find target segment
759 				 * for writes which can be full by checkpointed
760 				 * and newly written blocks.
761 				 */
762 				if (!f2fs_segment_has_free_slot(sbi, segno))
763 					goto next;
764 			}
765 		}
766 
767 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
768 			goto next;
769 
770 		if (is_atgc) {
771 			add_victim_entry(sbi, &p, segno);
772 			goto next;
773 		}
774 
775 		cost = get_gc_cost(sbi, segno, &p);
776 
777 		if (p.min_cost > cost) {
778 			p.min_segno = segno;
779 			p.min_cost = cost;
780 		}
781 next:
782 		if (nsearched >= p.max_search) {
783 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
784 				sm->last_victim[p.gc_mode] =
785 					last_victim + p.ofs_unit;
786 			else
787 				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
788 			sm->last_victim[p.gc_mode] %=
789 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
790 			break;
791 		}
792 	}
793 
794 	/* get victim for GC_AT/AT_SSR */
795 	if (is_atgc) {
796 		lookup_victim_by_age(sbi, &p);
797 		release_victim_entry(sbi);
798 	}
799 
800 	if (is_atgc && p.min_segno == NULL_SEGNO &&
801 			sm->elapsed_time < p.age_threshold) {
802 		p.age_threshold = 0;
803 		goto retry;
804 	}
805 
806 	if (p.min_segno != NULL_SEGNO) {
807 got_it:
808 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
809 got_result:
810 		if (p.alloc_mode == LFS) {
811 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
812 			if (gc_type == FG_GC)
813 				sbi->cur_victim_sec = secno;
814 			else
815 				set_bit(secno, dirty_i->victim_secmap);
816 		}
817 		ret = 0;
818 
819 	}
820 out:
821 	if (p.min_segno != NULL_SEGNO)
822 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
823 				sbi->cur_victim_sec,
824 				prefree_segments(sbi), free_segments(sbi));
825 	mutex_unlock(&dirty_i->seglist_lock);
826 
827 	return ret;
828 }
829 
830 static const struct victim_selection default_v_ops = {
831 	.get_victim = get_victim_by_default,
832 };
833 
834 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
835 {
836 	struct inode_entry *ie;
837 
838 	ie = radix_tree_lookup(&gc_list->iroot, ino);
839 	if (ie)
840 		return ie->inode;
841 	return NULL;
842 }
843 
844 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
845 {
846 	struct inode_entry *new_ie;
847 
848 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
849 		iput(inode);
850 		return;
851 	}
852 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab, GFP_NOFS);
853 	new_ie->inode = inode;
854 
855 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
856 	list_add_tail(&new_ie->list, &gc_list->ilist);
857 }
858 
859 static void put_gc_inode(struct gc_inode_list *gc_list)
860 {
861 	struct inode_entry *ie, *next_ie;
862 
863 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
864 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
865 		iput(ie->inode);
866 		list_del(&ie->list);
867 		kmem_cache_free(f2fs_inode_entry_slab, ie);
868 	}
869 }
870 
871 static int check_valid_map(struct f2fs_sb_info *sbi,
872 				unsigned int segno, int offset)
873 {
874 	struct sit_info *sit_i = SIT_I(sbi);
875 	struct seg_entry *sentry;
876 	int ret;
877 
878 	down_read(&sit_i->sentry_lock);
879 	sentry = get_seg_entry(sbi, segno);
880 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
881 	up_read(&sit_i->sentry_lock);
882 	return ret;
883 }
884 
885 /*
886  * This function compares node address got in summary with that in NAT.
887  * On validity, copy that node with cold status, otherwise (invalid node)
888  * ignore that.
889  */
890 static int gc_node_segment(struct f2fs_sb_info *sbi,
891 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
892 {
893 	struct f2fs_summary *entry;
894 	block_t start_addr;
895 	int off;
896 	int phase = 0;
897 	bool fggc = (gc_type == FG_GC);
898 	int submitted = 0;
899 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
900 
901 	start_addr = START_BLOCK(sbi, segno);
902 
903 next_step:
904 	entry = sum;
905 
906 	if (fggc && phase == 2)
907 		atomic_inc(&sbi->wb_sync_req[NODE]);
908 
909 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
910 		nid_t nid = le32_to_cpu(entry->nid);
911 		struct page *node_page;
912 		struct node_info ni;
913 		int err;
914 
915 		/* stop BG_GC if there is not enough free sections. */
916 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
917 			return submitted;
918 
919 		if (check_valid_map(sbi, segno, off) == 0)
920 			continue;
921 
922 		if (phase == 0) {
923 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
924 							META_NAT, true);
925 			continue;
926 		}
927 
928 		if (phase == 1) {
929 			f2fs_ra_node_page(sbi, nid);
930 			continue;
931 		}
932 
933 		/* phase == 2 */
934 		node_page = f2fs_get_node_page(sbi, nid);
935 		if (IS_ERR(node_page))
936 			continue;
937 
938 		/* block may become invalid during f2fs_get_node_page */
939 		if (check_valid_map(sbi, segno, off) == 0) {
940 			f2fs_put_page(node_page, 1);
941 			continue;
942 		}
943 
944 		if (f2fs_get_node_info(sbi, nid, &ni)) {
945 			f2fs_put_page(node_page, 1);
946 			continue;
947 		}
948 
949 		if (ni.blk_addr != start_addr + off) {
950 			f2fs_put_page(node_page, 1);
951 			continue;
952 		}
953 
954 		err = f2fs_move_node_page(node_page, gc_type);
955 		if (!err && gc_type == FG_GC)
956 			submitted++;
957 		stat_inc_node_blk_count(sbi, 1, gc_type);
958 	}
959 
960 	if (++phase < 3)
961 		goto next_step;
962 
963 	if (fggc)
964 		atomic_dec(&sbi->wb_sync_req[NODE]);
965 	return submitted;
966 }
967 
968 /*
969  * Calculate start block index indicating the given node offset.
970  * Be careful, caller should give this node offset only indicating direct node
971  * blocks. If any node offsets, which point the other types of node blocks such
972  * as indirect or double indirect node blocks, are given, it must be a caller's
973  * bug.
974  */
975 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
976 {
977 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
978 	unsigned int bidx;
979 
980 	if (node_ofs == 0)
981 		return 0;
982 
983 	if (node_ofs <= 2) {
984 		bidx = node_ofs - 1;
985 	} else if (node_ofs <= indirect_blks) {
986 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
987 
988 		bidx = node_ofs - 2 - dec;
989 	} else {
990 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
991 
992 		bidx = node_ofs - 5 - dec;
993 	}
994 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
995 }
996 
997 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
998 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
999 {
1000 	struct page *node_page;
1001 	nid_t nid;
1002 	unsigned int ofs_in_node;
1003 	block_t source_blkaddr;
1004 
1005 	nid = le32_to_cpu(sum->nid);
1006 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
1007 
1008 	node_page = f2fs_get_node_page(sbi, nid);
1009 	if (IS_ERR(node_page))
1010 		return false;
1011 
1012 	if (f2fs_get_node_info(sbi, nid, dni)) {
1013 		f2fs_put_page(node_page, 1);
1014 		return false;
1015 	}
1016 
1017 	if (sum->version != dni->version) {
1018 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
1019 			  __func__);
1020 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1021 	}
1022 
1023 	*nofs = ofs_of_node(node_page);
1024 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
1025 	f2fs_put_page(node_page, 1);
1026 
1027 	if (source_blkaddr != blkaddr) {
1028 #ifdef CONFIG_F2FS_CHECK_FS
1029 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
1030 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
1031 
1032 		if (unlikely(check_valid_map(sbi, segno, offset))) {
1033 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
1034 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u",
1035 					 blkaddr, source_blkaddr, segno);
1036 				f2fs_bug_on(sbi, 1);
1037 			}
1038 		}
1039 #endif
1040 		return false;
1041 	}
1042 	return true;
1043 }
1044 
1045 static int ra_data_block(struct inode *inode, pgoff_t index)
1046 {
1047 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1048 	struct address_space *mapping = inode->i_mapping;
1049 	struct dnode_of_data dn;
1050 	struct page *page;
1051 	struct extent_info ei = {0, 0, 0};
1052 	struct f2fs_io_info fio = {
1053 		.sbi = sbi,
1054 		.ino = inode->i_ino,
1055 		.type = DATA,
1056 		.temp = COLD,
1057 		.op = REQ_OP_READ,
1058 		.op_flags = 0,
1059 		.encrypted_page = NULL,
1060 		.in_list = false,
1061 		.retry = false,
1062 	};
1063 	int err;
1064 
1065 	page = f2fs_grab_cache_page(mapping, index, true);
1066 	if (!page)
1067 		return -ENOMEM;
1068 
1069 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
1070 		dn.data_blkaddr = ei.blk + index - ei.fofs;
1071 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1072 						DATA_GENERIC_ENHANCE_READ))) {
1073 			err = -EFSCORRUPTED;
1074 			goto put_page;
1075 		}
1076 		goto got_it;
1077 	}
1078 
1079 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1080 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
1081 	if (err)
1082 		goto put_page;
1083 	f2fs_put_dnode(&dn);
1084 
1085 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
1086 		err = -ENOENT;
1087 		goto put_page;
1088 	}
1089 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1090 						DATA_GENERIC_ENHANCE))) {
1091 		err = -EFSCORRUPTED;
1092 		goto put_page;
1093 	}
1094 got_it:
1095 	/* read page */
1096 	fio.page = page;
1097 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1098 
1099 	/*
1100 	 * don't cache encrypted data into meta inode until previous dirty
1101 	 * data were writebacked to avoid racing between GC and flush.
1102 	 */
1103 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1104 
1105 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1106 
1107 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
1108 					dn.data_blkaddr,
1109 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
1110 	if (!fio.encrypted_page) {
1111 		err = -ENOMEM;
1112 		goto put_page;
1113 	}
1114 
1115 	err = f2fs_submit_page_bio(&fio);
1116 	if (err)
1117 		goto put_encrypted_page;
1118 	f2fs_put_page(fio.encrypted_page, 0);
1119 	f2fs_put_page(page, 1);
1120 
1121 	f2fs_update_iostat(sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
1122 	f2fs_update_iostat(sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1123 
1124 	return 0;
1125 put_encrypted_page:
1126 	f2fs_put_page(fio.encrypted_page, 1);
1127 put_page:
1128 	f2fs_put_page(page, 1);
1129 	return err;
1130 }
1131 
1132 /*
1133  * Move data block via META_MAPPING while keeping locked data page.
1134  * This can be used to move blocks, aka LBAs, directly on disk.
1135  */
1136 static int move_data_block(struct inode *inode, block_t bidx,
1137 				int gc_type, unsigned int segno, int off)
1138 {
1139 	struct f2fs_io_info fio = {
1140 		.sbi = F2FS_I_SB(inode),
1141 		.ino = inode->i_ino,
1142 		.type = DATA,
1143 		.temp = COLD,
1144 		.op = REQ_OP_READ,
1145 		.op_flags = 0,
1146 		.encrypted_page = NULL,
1147 		.in_list = false,
1148 		.retry = false,
1149 	};
1150 	struct dnode_of_data dn;
1151 	struct f2fs_summary sum;
1152 	struct node_info ni;
1153 	struct page *page, *mpage;
1154 	block_t newaddr;
1155 	int err = 0;
1156 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
1157 	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
1158 				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
1159 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
1160 
1161 	/* do not read out */
1162 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
1163 	if (!page)
1164 		return -ENOMEM;
1165 
1166 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1167 		err = -ENOENT;
1168 		goto out;
1169 	}
1170 
1171 	if (f2fs_is_atomic_file(inode)) {
1172 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
1173 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
1174 		err = -EAGAIN;
1175 		goto out;
1176 	}
1177 
1178 	if (f2fs_is_pinned_file(inode)) {
1179 		f2fs_pin_file_control(inode, true);
1180 		err = -EAGAIN;
1181 		goto out;
1182 	}
1183 
1184 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1185 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
1186 	if (err)
1187 		goto out;
1188 
1189 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
1190 		ClearPageUptodate(page);
1191 		err = -ENOENT;
1192 		goto put_out;
1193 	}
1194 
1195 	/*
1196 	 * don't cache encrypted data into meta inode until previous dirty
1197 	 * data were writebacked to avoid racing between GC and flush.
1198 	 */
1199 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1200 
1201 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1202 
1203 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
1204 	if (err)
1205 		goto put_out;
1206 
1207 	/* read page */
1208 	fio.page = page;
1209 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1210 
1211 	if (lfs_mode)
1212 		down_write(&fio.sbi->io_order_lock);
1213 
1214 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
1215 					fio.old_blkaddr, false);
1216 	if (!mpage) {
1217 		err = -ENOMEM;
1218 		goto up_out;
1219 	}
1220 
1221 	fio.encrypted_page = mpage;
1222 
1223 	/* read source block in mpage */
1224 	if (!PageUptodate(mpage)) {
1225 		err = f2fs_submit_page_bio(&fio);
1226 		if (err) {
1227 			f2fs_put_page(mpage, 1);
1228 			goto up_out;
1229 		}
1230 
1231 		f2fs_update_iostat(fio.sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
1232 		f2fs_update_iostat(fio.sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1233 
1234 		lock_page(mpage);
1235 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
1236 						!PageUptodate(mpage))) {
1237 			err = -EIO;
1238 			f2fs_put_page(mpage, 1);
1239 			goto up_out;
1240 		}
1241 	}
1242 
1243 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
1244 
1245 	/* allocate block address */
1246 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
1247 				&sum, type, NULL);
1248 
1249 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
1250 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
1251 	if (!fio.encrypted_page) {
1252 		err = -ENOMEM;
1253 		f2fs_put_page(mpage, 1);
1254 		goto recover_block;
1255 	}
1256 
1257 	/* write target block */
1258 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
1259 	memcpy(page_address(fio.encrypted_page),
1260 				page_address(mpage), PAGE_SIZE);
1261 	f2fs_put_page(mpage, 1);
1262 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
1263 				fio.old_blkaddr, fio.old_blkaddr);
1264 	f2fs_invalidate_compress_page(fio.sbi, fio.old_blkaddr);
1265 
1266 	set_page_dirty(fio.encrypted_page);
1267 	if (clear_page_dirty_for_io(fio.encrypted_page))
1268 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
1269 
1270 	set_page_writeback(fio.encrypted_page);
1271 	ClearPageError(page);
1272 
1273 	fio.op = REQ_OP_WRITE;
1274 	fio.op_flags = REQ_SYNC;
1275 	fio.new_blkaddr = newaddr;
1276 	f2fs_submit_page_write(&fio);
1277 	if (fio.retry) {
1278 		err = -EAGAIN;
1279 		if (PageWriteback(fio.encrypted_page))
1280 			end_page_writeback(fio.encrypted_page);
1281 		goto put_page_out;
1282 	}
1283 
1284 	f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
1285 
1286 	f2fs_update_data_blkaddr(&dn, newaddr);
1287 	set_inode_flag(inode, FI_APPEND_WRITE);
1288 	if (page->index == 0)
1289 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
1290 put_page_out:
1291 	f2fs_put_page(fio.encrypted_page, 1);
1292 recover_block:
1293 	if (err)
1294 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
1295 							true, true, true);
1296 up_out:
1297 	if (lfs_mode)
1298 		up_write(&fio.sbi->io_order_lock);
1299 put_out:
1300 	f2fs_put_dnode(&dn);
1301 out:
1302 	f2fs_put_page(page, 1);
1303 	return err;
1304 }
1305 
1306 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
1307 							unsigned int segno, int off)
1308 {
1309 	struct page *page;
1310 	int err = 0;
1311 
1312 	page = f2fs_get_lock_data_page(inode, bidx, true);
1313 	if (IS_ERR(page))
1314 		return PTR_ERR(page);
1315 
1316 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1317 		err = -ENOENT;
1318 		goto out;
1319 	}
1320 
1321 	if (f2fs_is_atomic_file(inode)) {
1322 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
1323 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
1324 		err = -EAGAIN;
1325 		goto out;
1326 	}
1327 	if (f2fs_is_pinned_file(inode)) {
1328 		if (gc_type == FG_GC)
1329 			f2fs_pin_file_control(inode, true);
1330 		err = -EAGAIN;
1331 		goto out;
1332 	}
1333 
1334 	if (gc_type == BG_GC) {
1335 		if (PageWriteback(page)) {
1336 			err = -EAGAIN;
1337 			goto out;
1338 		}
1339 		set_page_dirty(page);
1340 		set_page_private_gcing(page);
1341 	} else {
1342 		struct f2fs_io_info fio = {
1343 			.sbi = F2FS_I_SB(inode),
1344 			.ino = inode->i_ino,
1345 			.type = DATA,
1346 			.temp = COLD,
1347 			.op = REQ_OP_WRITE,
1348 			.op_flags = REQ_SYNC,
1349 			.old_blkaddr = NULL_ADDR,
1350 			.page = page,
1351 			.encrypted_page = NULL,
1352 			.need_lock = LOCK_REQ,
1353 			.io_type = FS_GC_DATA_IO,
1354 		};
1355 		bool is_dirty = PageDirty(page);
1356 
1357 retry:
1358 		f2fs_wait_on_page_writeback(page, DATA, true, true);
1359 
1360 		set_page_dirty(page);
1361 		if (clear_page_dirty_for_io(page)) {
1362 			inode_dec_dirty_pages(inode);
1363 			f2fs_remove_dirty_inode(inode);
1364 		}
1365 
1366 		set_page_private_gcing(page);
1367 
1368 		err = f2fs_do_write_data_page(&fio);
1369 		if (err) {
1370 			clear_page_private_gcing(page);
1371 			if (err == -ENOMEM) {
1372 				congestion_wait(BLK_RW_ASYNC,
1373 						DEFAULT_IO_TIMEOUT);
1374 				goto retry;
1375 			}
1376 			if (is_dirty)
1377 				set_page_dirty(page);
1378 		}
1379 	}
1380 out:
1381 	f2fs_put_page(page, 1);
1382 	return err;
1383 }
1384 
1385 /*
1386  * This function tries to get parent node of victim data block, and identifies
1387  * data block validity. If the block is valid, copy that with cold status and
1388  * modify parent node.
1389  * If the parent node is not valid or the data block address is different,
1390  * the victim data block is ignored.
1391  */
1392 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1393 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
1394 		bool force_migrate)
1395 {
1396 	struct super_block *sb = sbi->sb;
1397 	struct f2fs_summary *entry;
1398 	block_t start_addr;
1399 	int off;
1400 	int phase = 0;
1401 	int submitted = 0;
1402 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1403 
1404 	start_addr = START_BLOCK(sbi, segno);
1405 
1406 next_step:
1407 	entry = sum;
1408 
1409 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1410 		struct page *data_page;
1411 		struct inode *inode;
1412 		struct node_info dni; /* dnode info for the data */
1413 		unsigned int ofs_in_node, nofs;
1414 		block_t start_bidx;
1415 		nid_t nid = le32_to_cpu(entry->nid);
1416 
1417 		/*
1418 		 * stop BG_GC if there is not enough free sections.
1419 		 * Or, stop GC if the segment becomes fully valid caused by
1420 		 * race condition along with SSR block allocation.
1421 		 */
1422 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1423 			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
1424 							BLKS_PER_SEC(sbi)))
1425 			return submitted;
1426 
1427 		if (check_valid_map(sbi, segno, off) == 0)
1428 			continue;
1429 
1430 		if (phase == 0) {
1431 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1432 							META_NAT, true);
1433 			continue;
1434 		}
1435 
1436 		if (phase == 1) {
1437 			f2fs_ra_node_page(sbi, nid);
1438 			continue;
1439 		}
1440 
1441 		/* Get an inode by ino with checking validity */
1442 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1443 			continue;
1444 
1445 		if (phase == 2) {
1446 			f2fs_ra_node_page(sbi, dni.ino);
1447 			continue;
1448 		}
1449 
1450 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1451 
1452 		if (phase == 3) {
1453 			inode = f2fs_iget(sb, dni.ino);
1454 			if (IS_ERR(inode) || is_bad_inode(inode))
1455 				continue;
1456 
1457 			if (!down_write_trylock(
1458 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1459 				iput(inode);
1460 				sbi->skipped_gc_rwsem++;
1461 				continue;
1462 			}
1463 
1464 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1465 								ofs_in_node;
1466 
1467 			if (f2fs_post_read_required(inode)) {
1468 				int err = ra_data_block(inode, start_bidx);
1469 
1470 				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1471 				if (err) {
1472 					iput(inode);
1473 					continue;
1474 				}
1475 				add_gc_inode(gc_list, inode);
1476 				continue;
1477 			}
1478 
1479 			data_page = f2fs_get_read_data_page(inode,
1480 						start_bidx, REQ_RAHEAD, true);
1481 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1482 			if (IS_ERR(data_page)) {
1483 				iput(inode);
1484 				continue;
1485 			}
1486 
1487 			f2fs_put_page(data_page, 0);
1488 			add_gc_inode(gc_list, inode);
1489 			continue;
1490 		}
1491 
1492 		/* phase 4 */
1493 		inode = find_gc_inode(gc_list, dni.ino);
1494 		if (inode) {
1495 			struct f2fs_inode_info *fi = F2FS_I(inode);
1496 			bool locked = false;
1497 			int err;
1498 
1499 			if (S_ISREG(inode->i_mode)) {
1500 				if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
1501 					continue;
1502 				if (!down_write_trylock(
1503 						&fi->i_gc_rwsem[WRITE])) {
1504 					sbi->skipped_gc_rwsem++;
1505 					up_write(&fi->i_gc_rwsem[READ]);
1506 					continue;
1507 				}
1508 				locked = true;
1509 
1510 				/* wait for all inflight aio data */
1511 				inode_dio_wait(inode);
1512 			}
1513 
1514 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1515 								+ ofs_in_node;
1516 			if (f2fs_post_read_required(inode))
1517 				err = move_data_block(inode, start_bidx,
1518 							gc_type, segno, off);
1519 			else
1520 				err = move_data_page(inode, start_bidx, gc_type,
1521 								segno, off);
1522 
1523 			if (!err && (gc_type == FG_GC ||
1524 					f2fs_post_read_required(inode)))
1525 				submitted++;
1526 
1527 			if (locked) {
1528 				up_write(&fi->i_gc_rwsem[WRITE]);
1529 				up_write(&fi->i_gc_rwsem[READ]);
1530 			}
1531 
1532 			stat_inc_data_blk_count(sbi, 1, gc_type);
1533 		}
1534 	}
1535 
1536 	if (++phase < 5)
1537 		goto next_step;
1538 
1539 	return submitted;
1540 }
1541 
1542 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1543 			int gc_type)
1544 {
1545 	struct sit_info *sit_i = SIT_I(sbi);
1546 	int ret;
1547 
1548 	down_write(&sit_i->sentry_lock);
1549 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1550 					      NO_CHECK_TYPE, LFS, 0);
1551 	up_write(&sit_i->sentry_lock);
1552 	return ret;
1553 }
1554 
1555 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1556 				unsigned int start_segno,
1557 				struct gc_inode_list *gc_list, int gc_type,
1558 				bool force_migrate)
1559 {
1560 	struct page *sum_page;
1561 	struct f2fs_summary_block *sum;
1562 	struct blk_plug plug;
1563 	unsigned int segno = start_segno;
1564 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1565 	int seg_freed = 0, migrated = 0;
1566 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1567 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1568 	int submitted = 0;
1569 
1570 	if (__is_large_section(sbi))
1571 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1572 
1573 	/*
1574 	 * zone-capacity can be less than zone-size in zoned devices,
1575 	 * resulting in less than expected usable segments in the zone,
1576 	 * calculate the end segno in the zone which can be garbage collected
1577 	 */
1578 	if (f2fs_sb_has_blkzoned(sbi))
1579 		end_segno -= sbi->segs_per_sec -
1580 					f2fs_usable_segs_in_sec(sbi, segno);
1581 
1582 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
1583 
1584 	/* readahead multi ssa blocks those have contiguous address */
1585 	if (__is_large_section(sbi))
1586 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1587 					end_segno - segno, META_SSA, true);
1588 
1589 	/* reference all summary page */
1590 	while (segno < end_segno) {
1591 		sum_page = f2fs_get_sum_page(sbi, segno++);
1592 		if (IS_ERR(sum_page)) {
1593 			int err = PTR_ERR(sum_page);
1594 
1595 			end_segno = segno - 1;
1596 			for (segno = start_segno; segno < end_segno; segno++) {
1597 				sum_page = find_get_page(META_MAPPING(sbi),
1598 						GET_SUM_BLOCK(sbi, segno));
1599 				f2fs_put_page(sum_page, 0);
1600 				f2fs_put_page(sum_page, 0);
1601 			}
1602 			return err;
1603 		}
1604 		unlock_page(sum_page);
1605 	}
1606 
1607 	blk_start_plug(&plug);
1608 
1609 	for (segno = start_segno; segno < end_segno; segno++) {
1610 
1611 		/* find segment summary of victim */
1612 		sum_page = find_get_page(META_MAPPING(sbi),
1613 					GET_SUM_BLOCK(sbi, segno));
1614 		f2fs_put_page(sum_page, 0);
1615 
1616 		if (get_valid_blocks(sbi, segno, false) == 0)
1617 			goto freed;
1618 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1619 				migrated >= sbi->migration_granularity)
1620 			goto skip;
1621 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1622 			goto skip;
1623 
1624 		sum = page_address(sum_page);
1625 		if (type != GET_SUM_TYPE((&sum->footer))) {
1626 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1627 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1628 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1629 			f2fs_stop_checkpoint(sbi, false);
1630 			goto skip;
1631 		}
1632 
1633 		/*
1634 		 * this is to avoid deadlock:
1635 		 * - lock_page(sum_page)         - f2fs_replace_block
1636 		 *  - check_valid_map()            - down_write(sentry_lock)
1637 		 *   - down_read(sentry_lock)     - change_curseg()
1638 		 *                                  - lock_page(sum_page)
1639 		 */
1640 		if (type == SUM_TYPE_NODE)
1641 			submitted += gc_node_segment(sbi, sum->entries, segno,
1642 								gc_type);
1643 		else
1644 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1645 							segno, gc_type,
1646 							force_migrate);
1647 
1648 		stat_inc_seg_count(sbi, type, gc_type);
1649 		migrated++;
1650 
1651 freed:
1652 		if (gc_type == FG_GC &&
1653 				get_valid_blocks(sbi, segno, false) == 0)
1654 			seg_freed++;
1655 
1656 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1657 			sbi->next_victim_seg[gc_type] = segno + 1;
1658 skip:
1659 		f2fs_put_page(sum_page, 0);
1660 	}
1661 
1662 	if (submitted)
1663 		f2fs_submit_merged_write(sbi,
1664 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1665 
1666 	blk_finish_plug(&plug);
1667 
1668 	stat_inc_call_count(sbi->stat_info);
1669 
1670 	return seg_freed;
1671 }
1672 
1673 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1674 			bool background, bool force, unsigned int segno)
1675 {
1676 	int gc_type = sync ? FG_GC : BG_GC;
1677 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1678 	int ret = 0;
1679 	struct cp_control cpc;
1680 	unsigned int init_segno = segno;
1681 	struct gc_inode_list gc_list = {
1682 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1683 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1684 	};
1685 	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1686 	unsigned long long first_skipped;
1687 	unsigned int skipped_round = 0, round = 0;
1688 
1689 	trace_f2fs_gc_begin(sbi->sb, sync, background,
1690 				get_pages(sbi, F2FS_DIRTY_NODES),
1691 				get_pages(sbi, F2FS_DIRTY_DENTS),
1692 				get_pages(sbi, F2FS_DIRTY_IMETA),
1693 				free_sections(sbi),
1694 				free_segments(sbi),
1695 				reserved_segments(sbi),
1696 				prefree_segments(sbi));
1697 
1698 	cpc.reason = __get_cp_reason(sbi);
1699 	sbi->skipped_gc_rwsem = 0;
1700 	first_skipped = last_skipped;
1701 gc_more:
1702 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1703 		ret = -EINVAL;
1704 		goto stop;
1705 	}
1706 	if (unlikely(f2fs_cp_error(sbi))) {
1707 		ret = -EIO;
1708 		goto stop;
1709 	}
1710 
1711 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1712 		/*
1713 		 * For example, if there are many prefree_segments below given
1714 		 * threshold, we can make them free by checkpoint. Then, we
1715 		 * secure free segments which doesn't need fggc any more.
1716 		 */
1717 		if (prefree_segments(sbi) &&
1718 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1719 			ret = f2fs_write_checkpoint(sbi, &cpc);
1720 			if (ret)
1721 				goto stop;
1722 		}
1723 		if (has_not_enough_free_secs(sbi, 0, 0))
1724 			gc_type = FG_GC;
1725 	}
1726 
1727 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1728 	if (gc_type == BG_GC && !background) {
1729 		ret = -EINVAL;
1730 		goto stop;
1731 	}
1732 	ret = __get_victim(sbi, &segno, gc_type);
1733 	if (ret)
1734 		goto stop;
1735 
1736 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type, force);
1737 	if (gc_type == FG_GC &&
1738 		seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
1739 		sec_freed++;
1740 	total_freed += seg_freed;
1741 
1742 	if (gc_type == FG_GC) {
1743 		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1744 						sbi->skipped_gc_rwsem)
1745 			skipped_round++;
1746 		last_skipped = sbi->skipped_atomic_files[FG_GC];
1747 		round++;
1748 	}
1749 
1750 	if (gc_type == FG_GC && seg_freed)
1751 		sbi->cur_victim_sec = NULL_SEGNO;
1752 
1753 	if (sync)
1754 		goto stop;
1755 
1756 	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1757 		if (skipped_round <= MAX_SKIP_GC_COUNT ||
1758 					skipped_round * 2 < round) {
1759 			segno = NULL_SEGNO;
1760 			goto gc_more;
1761 		}
1762 
1763 		if (first_skipped < last_skipped &&
1764 				(last_skipped - first_skipped) >
1765 						sbi->skipped_gc_rwsem) {
1766 			f2fs_drop_inmem_pages_all(sbi, true);
1767 			segno = NULL_SEGNO;
1768 			goto gc_more;
1769 		}
1770 		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1771 			ret = f2fs_write_checkpoint(sbi, &cpc);
1772 	}
1773 stop:
1774 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1775 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1776 
1777 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1778 				get_pages(sbi, F2FS_DIRTY_NODES),
1779 				get_pages(sbi, F2FS_DIRTY_DENTS),
1780 				get_pages(sbi, F2FS_DIRTY_IMETA),
1781 				free_sections(sbi),
1782 				free_segments(sbi),
1783 				reserved_segments(sbi),
1784 				prefree_segments(sbi));
1785 
1786 	up_write(&sbi->gc_lock);
1787 
1788 	put_gc_inode(&gc_list);
1789 
1790 	if (sync && !ret)
1791 		ret = sec_freed ? 0 : -EAGAIN;
1792 	return ret;
1793 }
1794 
1795 int __init f2fs_create_garbage_collection_cache(void)
1796 {
1797 	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
1798 					sizeof(struct victim_entry));
1799 	if (!victim_entry_slab)
1800 		return -ENOMEM;
1801 	return 0;
1802 }
1803 
1804 void f2fs_destroy_garbage_collection_cache(void)
1805 {
1806 	kmem_cache_destroy(victim_entry_slab);
1807 }
1808 
1809 static void init_atgc_management(struct f2fs_sb_info *sbi)
1810 {
1811 	struct atgc_management *am = &sbi->am;
1812 
1813 	if (test_opt(sbi, ATGC) &&
1814 		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
1815 		am->atgc_enabled = true;
1816 
1817 	am->root = RB_ROOT_CACHED;
1818 	INIT_LIST_HEAD(&am->victim_list);
1819 	am->victim_count = 0;
1820 
1821 	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
1822 	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
1823 	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
1824 	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
1825 }
1826 
1827 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1828 {
1829 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1830 
1831 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1832 
1833 	/* give warm/cold data area from slower device */
1834 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1835 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1836 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1837 
1838 	init_atgc_management(sbi);
1839 }
1840 
1841 static int free_segment_range(struct f2fs_sb_info *sbi,
1842 				unsigned int secs, bool gc_only)
1843 {
1844 	unsigned int segno, next_inuse, start, end;
1845 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1846 	int gc_mode, gc_type;
1847 	int err = 0;
1848 	int type;
1849 
1850 	/* Force block allocation for GC */
1851 	MAIN_SECS(sbi) -= secs;
1852 	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
1853 	end = MAIN_SEGS(sbi) - 1;
1854 
1855 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1856 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1857 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
1858 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1859 
1860 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1861 		if (sbi->next_victim_seg[gc_type] >= start)
1862 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1863 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1864 
1865 	/* Move out cursegs from the target range */
1866 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++)
1867 		f2fs_allocate_segment_for_resize(sbi, type, start, end);
1868 
1869 	/* do GC to move out valid blocks in the range */
1870 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1871 		struct gc_inode_list gc_list = {
1872 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1873 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1874 		};
1875 
1876 		do_garbage_collect(sbi, segno, &gc_list, FG_GC, true);
1877 		put_gc_inode(&gc_list);
1878 
1879 		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
1880 			err = -EAGAIN;
1881 			goto out;
1882 		}
1883 		if (fatal_signal_pending(current)) {
1884 			err = -ERESTARTSYS;
1885 			goto out;
1886 		}
1887 	}
1888 	if (gc_only)
1889 		goto out;
1890 
1891 	err = f2fs_write_checkpoint(sbi, &cpc);
1892 	if (err)
1893 		goto out;
1894 
1895 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1896 	if (next_inuse <= end) {
1897 		f2fs_err(sbi, "segno %u should be free but still inuse!",
1898 			 next_inuse);
1899 		f2fs_bug_on(sbi, 1);
1900 	}
1901 out:
1902 	MAIN_SECS(sbi) += secs;
1903 	return err;
1904 }
1905 
1906 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1907 {
1908 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1909 	int section_count;
1910 	int segment_count;
1911 	int segment_count_main;
1912 	long long block_count;
1913 	int segs = secs * sbi->segs_per_sec;
1914 
1915 	down_write(&sbi->sb_lock);
1916 
1917 	section_count = le32_to_cpu(raw_sb->section_count);
1918 	segment_count = le32_to_cpu(raw_sb->segment_count);
1919 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1920 	block_count = le64_to_cpu(raw_sb->block_count);
1921 
1922 	raw_sb->section_count = cpu_to_le32(section_count + secs);
1923 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1924 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1925 	raw_sb->block_count = cpu_to_le64(block_count +
1926 					(long long)segs * sbi->blocks_per_seg);
1927 	if (f2fs_is_multi_device(sbi)) {
1928 		int last_dev = sbi->s_ndevs - 1;
1929 		int dev_segs =
1930 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
1931 
1932 		raw_sb->devs[last_dev].total_segments =
1933 						cpu_to_le32(dev_segs + segs);
1934 	}
1935 
1936 	up_write(&sbi->sb_lock);
1937 }
1938 
1939 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1940 {
1941 	int segs = secs * sbi->segs_per_sec;
1942 	long long blks = (long long)segs * sbi->blocks_per_seg;
1943 	long long user_block_count =
1944 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1945 
1946 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1947 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1948 	MAIN_SECS(sbi) += secs;
1949 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1950 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1951 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
1952 
1953 	if (f2fs_is_multi_device(sbi)) {
1954 		int last_dev = sbi->s_ndevs - 1;
1955 
1956 		FDEV(last_dev).total_segments =
1957 				(int)FDEV(last_dev).total_segments + segs;
1958 		FDEV(last_dev).end_blk =
1959 				(long long)FDEV(last_dev).end_blk + blks;
1960 #ifdef CONFIG_BLK_DEV_ZONED
1961 		FDEV(last_dev).nr_blkz = (int)FDEV(last_dev).nr_blkz +
1962 					(int)(blks >> sbi->log_blocks_per_blkz);
1963 #endif
1964 	}
1965 }
1966 
1967 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1968 {
1969 	__u64 old_block_count, shrunk_blocks;
1970 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1971 	unsigned int secs;
1972 	int err = 0;
1973 	__u32 rem;
1974 
1975 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
1976 	if (block_count > old_block_count)
1977 		return -EINVAL;
1978 
1979 	if (f2fs_is_multi_device(sbi)) {
1980 		int last_dev = sbi->s_ndevs - 1;
1981 		__u64 last_segs = FDEV(last_dev).total_segments;
1982 
1983 		if (block_count + last_segs * sbi->blocks_per_seg <=
1984 								old_block_count)
1985 			return -EINVAL;
1986 	}
1987 
1988 	/* new fs size should align to section size */
1989 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
1990 	if (rem)
1991 		return -EINVAL;
1992 
1993 	if (block_count == old_block_count)
1994 		return 0;
1995 
1996 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
1997 		f2fs_err(sbi, "Should run fsck to repair first.");
1998 		return -EFSCORRUPTED;
1999 	}
2000 
2001 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
2002 		f2fs_err(sbi, "Checkpoint should be enabled.");
2003 		return -EINVAL;
2004 	}
2005 
2006 	shrunk_blocks = old_block_count - block_count;
2007 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
2008 
2009 	/* stop other GC */
2010 	if (!down_write_trylock(&sbi->gc_lock))
2011 		return -EAGAIN;
2012 
2013 	/* stop CP to protect MAIN_SEC in free_segment_range */
2014 	f2fs_lock_op(sbi);
2015 
2016 	spin_lock(&sbi->stat_lock);
2017 	if (shrunk_blocks + valid_user_blocks(sbi) +
2018 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2019 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2020 		err = -ENOSPC;
2021 	spin_unlock(&sbi->stat_lock);
2022 
2023 	if (err)
2024 		goto out_unlock;
2025 
2026 	err = free_segment_range(sbi, secs, true);
2027 
2028 out_unlock:
2029 	f2fs_unlock_op(sbi);
2030 	up_write(&sbi->gc_lock);
2031 	if (err)
2032 		return err;
2033 
2034 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
2035 
2036 	freeze_super(sbi->sb);
2037 	down_write(&sbi->gc_lock);
2038 	down_write(&sbi->cp_global_sem);
2039 
2040 	spin_lock(&sbi->stat_lock);
2041 	if (shrunk_blocks + valid_user_blocks(sbi) +
2042 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2043 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2044 		err = -ENOSPC;
2045 	else
2046 		sbi->user_block_count -= shrunk_blocks;
2047 	spin_unlock(&sbi->stat_lock);
2048 	if (err)
2049 		goto out_err;
2050 
2051 	err = free_segment_range(sbi, secs, false);
2052 	if (err)
2053 		goto recover_out;
2054 
2055 	update_sb_metadata(sbi, -secs);
2056 
2057 	err = f2fs_commit_super(sbi, false);
2058 	if (err) {
2059 		update_sb_metadata(sbi, secs);
2060 		goto recover_out;
2061 	}
2062 
2063 	update_fs_metadata(sbi, -secs);
2064 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2065 	set_sbi_flag(sbi, SBI_IS_DIRTY);
2066 
2067 	err = f2fs_write_checkpoint(sbi, &cpc);
2068 	if (err) {
2069 		update_fs_metadata(sbi, secs);
2070 		update_sb_metadata(sbi, secs);
2071 		f2fs_commit_super(sbi, false);
2072 	}
2073 recover_out:
2074 	if (err) {
2075 		set_sbi_flag(sbi, SBI_NEED_FSCK);
2076 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
2077 
2078 		spin_lock(&sbi->stat_lock);
2079 		sbi->user_block_count += shrunk_blocks;
2080 		spin_unlock(&sbi->stat_lock);
2081 	}
2082 out_err:
2083 	up_write(&sbi->cp_global_sem);
2084 	up_write(&sbi->gc_lock);
2085 	thaw_super(sbi->sb);
2086 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2087 	return err;
2088 }
2089