xref: /openbmc/linux/fs/f2fs/gc.c (revision 34fa67e7)
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 
39 	wait_ms = gc_th->min_sleep_time;
40 
41 	set_freezable();
42 	do {
43 		bool sync_mode, foreground = false;
44 
45 		wait_event_interruptible_timeout(*wq,
46 				kthread_should_stop() || freezing(current) ||
47 				waitqueue_active(fggc_wq) ||
48 				gc_th->gc_wake,
49 				msecs_to_jiffies(wait_ms));
50 
51 		if (test_opt(sbi, GC_MERGE) && waitqueue_active(fggc_wq))
52 			foreground = true;
53 
54 		/* give it a try one time */
55 		if (gc_th->gc_wake)
56 			gc_th->gc_wake = 0;
57 
58 		if (try_to_freeze()) {
59 			stat_other_skip_bggc_count(sbi);
60 			continue;
61 		}
62 		if (kthread_should_stop())
63 			break;
64 
65 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
66 			increase_sleep_time(gc_th, &wait_ms);
67 			stat_other_skip_bggc_count(sbi);
68 			continue;
69 		}
70 
71 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
72 			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
73 			f2fs_stop_checkpoint(sbi, false);
74 		}
75 
76 		if (!sb_start_write_trylock(sbi->sb)) {
77 			stat_other_skip_bggc_count(sbi);
78 			continue;
79 		}
80 
81 		/*
82 		 * [GC triggering condition]
83 		 * 0. GC is not conducted currently.
84 		 * 1. There are enough dirty segments.
85 		 * 2. IO subsystem is idle by checking the # of writeback pages.
86 		 * 3. IO subsystem is idle by checking the # of requests in
87 		 *    bdev's request list.
88 		 *
89 		 * Note) We have to avoid triggering GCs frequently.
90 		 * Because it is possible that some segments can be
91 		 * invalidated soon after by user update or deletion.
92 		 * So, I'd like to wait some time to collect dirty segments.
93 		 */
94 		if (sbi->gc_mode == GC_URGENT_HIGH) {
95 			wait_ms = gc_th->urgent_sleep_time;
96 			down_write(&sbi->gc_lock);
97 			goto do_gc;
98 		}
99 
100 		if (foreground) {
101 			down_write(&sbi->gc_lock);
102 			goto do_gc;
103 		} else if (!down_write_trylock(&sbi->gc_lock)) {
104 			stat_other_skip_bggc_count(sbi);
105 			goto next;
106 		}
107 
108 		if (!is_idle(sbi, GC_TIME)) {
109 			increase_sleep_time(gc_th, &wait_ms);
110 			up_write(&sbi->gc_lock);
111 			stat_io_skip_bggc_count(sbi);
112 			goto next;
113 		}
114 
115 		if (has_enough_invalid_blocks(sbi))
116 			decrease_sleep_time(gc_th, &wait_ms);
117 		else
118 			increase_sleep_time(gc_th, &wait_ms);
119 do_gc:
120 		if (!foreground)
121 			stat_inc_bggc_count(sbi->stat_info);
122 
123 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
124 
125 		/* foreground GC was been triggered via f2fs_balance_fs() */
126 		if (foreground)
127 			sync_mode = false;
128 
129 		/* if return value is not zero, no victim was selected */
130 		if (f2fs_gc(sbi, sync_mode, !foreground, false, NULL_SEGNO))
131 			wait_ms = gc_th->no_gc_sleep_time;
132 
133 		if (foreground)
134 			wake_up_all(&gc_th->fggc_wq);
135 
136 		trace_f2fs_background_gc(sbi->sb, wait_ms,
137 				prefree_segments(sbi), free_segments(sbi));
138 
139 		/* balancing f2fs's metadata periodically */
140 		f2fs_balance_fs_bg(sbi, true);
141 next:
142 		sb_end_write(sbi->sb);
143 
144 	} while (!kthread_should_stop());
145 	return 0;
146 }
147 
148 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
149 {
150 	struct f2fs_gc_kthread *gc_th;
151 	dev_t dev = sbi->sb->s_bdev->bd_dev;
152 	int err = 0;
153 
154 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
155 	if (!gc_th) {
156 		err = -ENOMEM;
157 		goto out;
158 	}
159 
160 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
161 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
162 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
163 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
164 
165 	gc_th->gc_wake = 0;
166 
167 	sbi->gc_thread = gc_th;
168 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
169 	init_waitqueue_head(&sbi->gc_thread->fggc_wq);
170 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
171 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
172 	if (IS_ERR(gc_th->f2fs_gc_task)) {
173 		err = PTR_ERR(gc_th->f2fs_gc_task);
174 		kfree(gc_th);
175 		sbi->gc_thread = NULL;
176 	}
177 out:
178 	return err;
179 }
180 
181 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
182 {
183 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
184 
185 	if (!gc_th)
186 		return;
187 	kthread_stop(gc_th->f2fs_gc_task);
188 	wake_up_all(&gc_th->fggc_wq);
189 	kfree(gc_th);
190 	sbi->gc_thread = NULL;
191 }
192 
193 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
194 {
195 	int gc_mode;
196 
197 	if (gc_type == BG_GC) {
198 		if (sbi->am.atgc_enabled)
199 			gc_mode = GC_AT;
200 		else
201 			gc_mode = GC_CB;
202 	} else {
203 		gc_mode = GC_GREEDY;
204 	}
205 
206 	switch (sbi->gc_mode) {
207 	case GC_IDLE_CB:
208 		gc_mode = GC_CB;
209 		break;
210 	case GC_IDLE_GREEDY:
211 	case GC_URGENT_HIGH:
212 		gc_mode = GC_GREEDY;
213 		break;
214 	case GC_IDLE_AT:
215 		gc_mode = GC_AT;
216 		break;
217 	}
218 
219 	return gc_mode;
220 }
221 
222 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
223 			int type, struct victim_sel_policy *p)
224 {
225 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
226 
227 	if (p->alloc_mode == SSR) {
228 		p->gc_mode = GC_GREEDY;
229 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
230 		p->max_search = dirty_i->nr_dirty[type];
231 		p->ofs_unit = 1;
232 	} else if (p->alloc_mode == AT_SSR) {
233 		p->gc_mode = GC_GREEDY;
234 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
235 		p->max_search = dirty_i->nr_dirty[type];
236 		p->ofs_unit = 1;
237 	} else {
238 		p->gc_mode = select_gc_type(sbi, gc_type);
239 		p->ofs_unit = sbi->segs_per_sec;
240 		if (__is_large_section(sbi)) {
241 			p->dirty_bitmap = dirty_i->dirty_secmap;
242 			p->max_search = count_bits(p->dirty_bitmap,
243 						0, MAIN_SECS(sbi));
244 		} else {
245 			p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
246 			p->max_search = dirty_i->nr_dirty[DIRTY];
247 		}
248 	}
249 
250 	/*
251 	 * adjust candidates range, should select all dirty segments for
252 	 * foreground GC and urgent GC cases.
253 	 */
254 	if (gc_type != FG_GC &&
255 			(sbi->gc_mode != GC_URGENT_HIGH) &&
256 			(p->gc_mode != GC_AT && p->alloc_mode != AT_SSR) &&
257 			p->max_search > sbi->max_victim_search)
258 		p->max_search = sbi->max_victim_search;
259 
260 	/* let's select beginning hot/small space first in no_heap mode*/
261 	if (f2fs_need_rand_seg(sbi))
262 		p->offset = prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec);
263 	else if (test_opt(sbi, NOHEAP) &&
264 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
265 		p->offset = 0;
266 	else
267 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
268 }
269 
270 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
271 				struct victim_sel_policy *p)
272 {
273 	/* SSR allocates in a segment unit */
274 	if (p->alloc_mode == SSR)
275 		return sbi->blocks_per_seg;
276 	else if (p->alloc_mode == AT_SSR)
277 		return UINT_MAX;
278 
279 	/* LFS */
280 	if (p->gc_mode == GC_GREEDY)
281 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
282 	else if (p->gc_mode == GC_CB)
283 		return UINT_MAX;
284 	else if (p->gc_mode == GC_AT)
285 		return UINT_MAX;
286 	else /* No other gc_mode */
287 		return 0;
288 }
289 
290 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
291 {
292 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
293 	unsigned int secno;
294 
295 	/*
296 	 * If the gc_type is FG_GC, we can select victim segments
297 	 * selected by background GC before.
298 	 * Those segments guarantee they have small valid blocks.
299 	 */
300 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
301 		if (sec_usage_check(sbi, secno))
302 			continue;
303 		clear_bit(secno, dirty_i->victim_secmap);
304 		return GET_SEG_FROM_SEC(sbi, secno);
305 	}
306 	return NULL_SEGNO;
307 }
308 
309 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
310 {
311 	struct sit_info *sit_i = SIT_I(sbi);
312 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
313 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
314 	unsigned long long mtime = 0;
315 	unsigned int vblocks;
316 	unsigned char age = 0;
317 	unsigned char u;
318 	unsigned int i;
319 	unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi, segno);
320 
321 	for (i = 0; i < usable_segs_per_sec; i++)
322 		mtime += get_seg_entry(sbi, start + i)->mtime;
323 	vblocks = get_valid_blocks(sbi, segno, true);
324 
325 	mtime = div_u64(mtime, usable_segs_per_sec);
326 	vblocks = div_u64(vblocks, usable_segs_per_sec);
327 
328 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
329 
330 	/* Handle if the system time has changed by the user */
331 	if (mtime < sit_i->min_mtime)
332 		sit_i->min_mtime = mtime;
333 	if (mtime > sit_i->max_mtime)
334 		sit_i->max_mtime = mtime;
335 	if (sit_i->max_mtime != sit_i->min_mtime)
336 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
337 				sit_i->max_mtime - sit_i->min_mtime);
338 
339 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
340 }
341 
342 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
343 			unsigned int segno, struct victim_sel_policy *p)
344 {
345 	if (p->alloc_mode == SSR)
346 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
347 
348 	/* alloc_mode == LFS */
349 	if (p->gc_mode == GC_GREEDY)
350 		return get_valid_blocks(sbi, segno, true);
351 	else if (p->gc_mode == GC_CB)
352 		return get_cb_cost(sbi, segno);
353 
354 	f2fs_bug_on(sbi, 1);
355 	return 0;
356 }
357 
358 static unsigned int count_bits(const unsigned long *addr,
359 				unsigned int offset, unsigned int len)
360 {
361 	unsigned int end = offset + len, sum = 0;
362 
363 	while (offset < end) {
364 		if (test_bit(offset++, addr))
365 			++sum;
366 	}
367 	return sum;
368 }
369 
370 static struct victim_entry *attach_victim_entry(struct f2fs_sb_info *sbi,
371 				unsigned long long mtime, unsigned int segno,
372 				struct rb_node *parent, struct rb_node **p,
373 				bool left_most)
374 {
375 	struct atgc_management *am = &sbi->am;
376 	struct victim_entry *ve;
377 
378 	ve =  f2fs_kmem_cache_alloc(victim_entry_slab,
379 				GFP_NOFS, true, NULL);
380 
381 	ve->mtime = mtime;
382 	ve->segno = segno;
383 
384 	rb_link_node(&ve->rb_node, parent, p);
385 	rb_insert_color_cached(&ve->rb_node, &am->root, left_most);
386 
387 	list_add_tail(&ve->list, &am->victim_list);
388 
389 	am->victim_count++;
390 
391 	return ve;
392 }
393 
394 static void insert_victim_entry(struct f2fs_sb_info *sbi,
395 				unsigned long long mtime, unsigned int segno)
396 {
397 	struct atgc_management *am = &sbi->am;
398 	struct rb_node **p;
399 	struct rb_node *parent = NULL;
400 	bool left_most = true;
401 
402 	p = f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, mtime, &left_most);
403 	attach_victim_entry(sbi, mtime, segno, parent, p, left_most);
404 }
405 
406 static void add_victim_entry(struct f2fs_sb_info *sbi,
407 				struct victim_sel_policy *p, unsigned int segno)
408 {
409 	struct sit_info *sit_i = SIT_I(sbi);
410 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
411 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
412 	unsigned long long mtime = 0;
413 	unsigned int i;
414 
415 	if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
416 		if (p->gc_mode == GC_AT &&
417 			get_valid_blocks(sbi, segno, true) == 0)
418 			return;
419 	}
420 
421 	for (i = 0; i < sbi->segs_per_sec; i++)
422 		mtime += get_seg_entry(sbi, start + i)->mtime;
423 	mtime = div_u64(mtime, sbi->segs_per_sec);
424 
425 	/* Handle if the system time has changed by the user */
426 	if (mtime < sit_i->min_mtime)
427 		sit_i->min_mtime = mtime;
428 	if (mtime > sit_i->max_mtime)
429 		sit_i->max_mtime = mtime;
430 	if (mtime < sit_i->dirty_min_mtime)
431 		sit_i->dirty_min_mtime = mtime;
432 	if (mtime > sit_i->dirty_max_mtime)
433 		sit_i->dirty_max_mtime = mtime;
434 
435 	/* don't choose young section as candidate */
436 	if (sit_i->dirty_max_mtime - mtime < p->age_threshold)
437 		return;
438 
439 	insert_victim_entry(sbi, mtime, segno);
440 }
441 
442 static struct rb_node *lookup_central_victim(struct f2fs_sb_info *sbi,
443 						struct victim_sel_policy *p)
444 {
445 	struct atgc_management *am = &sbi->am;
446 	struct rb_node *parent = NULL;
447 	bool left_most;
448 
449 	f2fs_lookup_rb_tree_ext(sbi, &am->root, &parent, p->age, &left_most);
450 
451 	return parent;
452 }
453 
454 static void atgc_lookup_victim(struct f2fs_sb_info *sbi,
455 						struct victim_sel_policy *p)
456 {
457 	struct sit_info *sit_i = SIT_I(sbi);
458 	struct atgc_management *am = &sbi->am;
459 	struct rb_root_cached *root = &am->root;
460 	struct rb_node *node;
461 	struct rb_entry *re;
462 	struct victim_entry *ve;
463 	unsigned long long total_time;
464 	unsigned long long age, u, accu;
465 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
466 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
467 	unsigned int sec_blocks = BLKS_PER_SEC(sbi);
468 	unsigned int vblocks;
469 	unsigned int dirty_threshold = max(am->max_candidate_count,
470 					am->candidate_ratio *
471 					am->victim_count / 100);
472 	unsigned int age_weight = am->age_weight;
473 	unsigned int cost;
474 	unsigned int iter = 0;
475 
476 	if (max_mtime < min_mtime)
477 		return;
478 
479 	max_mtime += 1;
480 	total_time = max_mtime - min_mtime;
481 
482 	accu = div64_u64(ULLONG_MAX, total_time);
483 	accu = min_t(unsigned long long, div_u64(accu, 100),
484 					DEFAULT_ACCURACY_CLASS);
485 
486 	node = rb_first_cached(root);
487 next:
488 	re = rb_entry_safe(node, struct rb_entry, rb_node);
489 	if (!re)
490 		return;
491 
492 	ve = (struct victim_entry *)re;
493 
494 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
495 		goto skip;
496 
497 	/* age = 10000 * x% * 60 */
498 	age = div64_u64(accu * (max_mtime - ve->mtime), total_time) *
499 								age_weight;
500 
501 	vblocks = get_valid_blocks(sbi, ve->segno, true);
502 	f2fs_bug_on(sbi, !vblocks || vblocks == sec_blocks);
503 
504 	/* u = 10000 * x% * 40 */
505 	u = div64_u64(accu * (sec_blocks - vblocks), sec_blocks) *
506 							(100 - age_weight);
507 
508 	f2fs_bug_on(sbi, age + u >= UINT_MAX);
509 
510 	cost = UINT_MAX - (age + u);
511 	iter++;
512 
513 	if (cost < p->min_cost ||
514 			(cost == p->min_cost && age > p->oldest_age)) {
515 		p->min_cost = cost;
516 		p->oldest_age = age;
517 		p->min_segno = ve->segno;
518 	}
519 skip:
520 	if (iter < dirty_threshold) {
521 		node = rb_next(node);
522 		goto next;
523 	}
524 }
525 
526 /*
527  * select candidates around source section in range of
528  * [target - dirty_threshold, target + dirty_threshold]
529  */
530 static void atssr_lookup_victim(struct f2fs_sb_info *sbi,
531 						struct victim_sel_policy *p)
532 {
533 	struct sit_info *sit_i = SIT_I(sbi);
534 	struct atgc_management *am = &sbi->am;
535 	struct rb_node *node;
536 	struct rb_entry *re;
537 	struct victim_entry *ve;
538 	unsigned long long age;
539 	unsigned long long max_mtime = sit_i->dirty_max_mtime;
540 	unsigned long long min_mtime = sit_i->dirty_min_mtime;
541 	unsigned int seg_blocks = sbi->blocks_per_seg;
542 	unsigned int vblocks;
543 	unsigned int dirty_threshold = max(am->max_candidate_count,
544 					am->candidate_ratio *
545 					am->victim_count / 100);
546 	unsigned int cost;
547 	unsigned int iter = 0;
548 	int stage = 0;
549 
550 	if (max_mtime < min_mtime)
551 		return;
552 	max_mtime += 1;
553 next_stage:
554 	node = lookup_central_victim(sbi, p);
555 next_node:
556 	re = rb_entry_safe(node, struct rb_entry, rb_node);
557 	if (!re) {
558 		if (stage == 0)
559 			goto skip_stage;
560 		return;
561 	}
562 
563 	ve = (struct victim_entry *)re;
564 
565 	if (ve->mtime >= max_mtime || ve->mtime < min_mtime)
566 		goto skip_node;
567 
568 	age = max_mtime - ve->mtime;
569 
570 	vblocks = get_seg_entry(sbi, ve->segno)->ckpt_valid_blocks;
571 	f2fs_bug_on(sbi, !vblocks);
572 
573 	/* rare case */
574 	if (vblocks == seg_blocks)
575 		goto skip_node;
576 
577 	iter++;
578 
579 	age = max_mtime - abs(p->age - age);
580 	cost = UINT_MAX - vblocks;
581 
582 	if (cost < p->min_cost ||
583 			(cost == p->min_cost && age > p->oldest_age)) {
584 		p->min_cost = cost;
585 		p->oldest_age = age;
586 		p->min_segno = ve->segno;
587 	}
588 skip_node:
589 	if (iter < dirty_threshold) {
590 		if (stage == 0)
591 			node = rb_prev(node);
592 		else if (stage == 1)
593 			node = rb_next(node);
594 		goto next_node;
595 	}
596 skip_stage:
597 	if (stage < 1) {
598 		stage++;
599 		iter = 0;
600 		goto next_stage;
601 	}
602 }
603 static void lookup_victim_by_age(struct f2fs_sb_info *sbi,
604 						struct victim_sel_policy *p)
605 {
606 	f2fs_bug_on(sbi, !f2fs_check_rb_tree_consistence(sbi,
607 						&sbi->am.root, true));
608 
609 	if (p->gc_mode == GC_AT)
610 		atgc_lookup_victim(sbi, p);
611 	else if (p->alloc_mode == AT_SSR)
612 		atssr_lookup_victim(sbi, p);
613 	else
614 		f2fs_bug_on(sbi, 1);
615 }
616 
617 static void release_victim_entry(struct f2fs_sb_info *sbi)
618 {
619 	struct atgc_management *am = &sbi->am;
620 	struct victim_entry *ve, *tmp;
621 
622 	list_for_each_entry_safe(ve, tmp, &am->victim_list, list) {
623 		list_del(&ve->list);
624 		kmem_cache_free(victim_entry_slab, ve);
625 		am->victim_count--;
626 	}
627 
628 	am->root = RB_ROOT_CACHED;
629 
630 	f2fs_bug_on(sbi, am->victim_count);
631 	f2fs_bug_on(sbi, !list_empty(&am->victim_list));
632 }
633 
634 /*
635  * This function is called from two paths.
636  * One is garbage collection and the other is SSR segment selection.
637  * When it is called during GC, it just gets a victim segment
638  * and it does not remove it from dirty seglist.
639  * When it is called from SSR segment selection, it finds a segment
640  * which has minimum valid blocks and removes it from dirty seglist.
641  */
642 static int get_victim_by_default(struct f2fs_sb_info *sbi,
643 			unsigned int *result, int gc_type, int type,
644 			char alloc_mode, unsigned long long age)
645 {
646 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
647 	struct sit_info *sm = SIT_I(sbi);
648 	struct victim_sel_policy p;
649 	unsigned int secno, last_victim;
650 	unsigned int last_segment;
651 	unsigned int nsearched;
652 	bool is_atgc;
653 	int ret = 0;
654 
655 	mutex_lock(&dirty_i->seglist_lock);
656 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
657 
658 	p.alloc_mode = alloc_mode;
659 	p.age = age;
660 	p.age_threshold = sbi->am.age_threshold;
661 
662 retry:
663 	select_policy(sbi, gc_type, type, &p);
664 	p.min_segno = NULL_SEGNO;
665 	p.oldest_age = 0;
666 	p.min_cost = get_max_cost(sbi, &p);
667 
668 	is_atgc = (p.gc_mode == GC_AT || p.alloc_mode == AT_SSR);
669 	nsearched = 0;
670 
671 	if (is_atgc)
672 		SIT_I(sbi)->dirty_min_mtime = ULLONG_MAX;
673 
674 	if (*result != NULL_SEGNO) {
675 		if (!get_valid_blocks(sbi, *result, false)) {
676 			ret = -ENODATA;
677 			goto out;
678 		}
679 
680 		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
681 			ret = -EBUSY;
682 		else
683 			p.min_segno = *result;
684 		goto out;
685 	}
686 
687 	ret = -ENODATA;
688 	if (p.max_search == 0)
689 		goto out;
690 
691 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
692 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
693 			p.min_segno = sbi->next_victim_seg[BG_GC];
694 			*result = p.min_segno;
695 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
696 			goto got_result;
697 		}
698 		if (gc_type == FG_GC &&
699 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
700 			p.min_segno = sbi->next_victim_seg[FG_GC];
701 			*result = p.min_segno;
702 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
703 			goto got_result;
704 		}
705 	}
706 
707 	last_victim = sm->last_victim[p.gc_mode];
708 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
709 		p.min_segno = check_bg_victims(sbi);
710 		if (p.min_segno != NULL_SEGNO)
711 			goto got_it;
712 	}
713 
714 	while (1) {
715 		unsigned long cost, *dirty_bitmap;
716 		unsigned int unit_no, segno;
717 
718 		dirty_bitmap = p.dirty_bitmap;
719 		unit_no = find_next_bit(dirty_bitmap,
720 				last_segment / p.ofs_unit,
721 				p.offset / p.ofs_unit);
722 		segno = unit_no * p.ofs_unit;
723 		if (segno >= last_segment) {
724 			if (sm->last_victim[p.gc_mode]) {
725 				last_segment =
726 					sm->last_victim[p.gc_mode];
727 				sm->last_victim[p.gc_mode] = 0;
728 				p.offset = 0;
729 				continue;
730 			}
731 			break;
732 		}
733 
734 		p.offset = segno + p.ofs_unit;
735 		nsearched++;
736 
737 #ifdef CONFIG_F2FS_CHECK_FS
738 		/*
739 		 * skip selecting the invalid segno (that is failed due to block
740 		 * validity check failure during GC) to avoid endless GC loop in
741 		 * such cases.
742 		 */
743 		if (test_bit(segno, sm->invalid_segmap))
744 			goto next;
745 #endif
746 
747 		secno = GET_SEC_FROM_SEG(sbi, segno);
748 
749 		if (sec_usage_check(sbi, secno))
750 			goto next;
751 
752 		/* Don't touch checkpointed data */
753 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
754 			if (p.alloc_mode == LFS) {
755 				/*
756 				 * LFS is set to find source section during GC.
757 				 * The victim should have no checkpointed data.
758 				 */
759 				if (get_ckpt_valid_blocks(sbi, segno, true))
760 					goto next;
761 			} else {
762 				/*
763 				 * SSR | AT_SSR are set to find target segment
764 				 * for writes which can be full by checkpointed
765 				 * and newly written blocks.
766 				 */
767 				if (!f2fs_segment_has_free_slot(sbi, segno))
768 					goto next;
769 			}
770 		}
771 
772 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
773 			goto next;
774 
775 		if (is_atgc) {
776 			add_victim_entry(sbi, &p, segno);
777 			goto next;
778 		}
779 
780 		cost = get_gc_cost(sbi, segno, &p);
781 
782 		if (p.min_cost > cost) {
783 			p.min_segno = segno;
784 			p.min_cost = cost;
785 		}
786 next:
787 		if (nsearched >= p.max_search) {
788 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
789 				sm->last_victim[p.gc_mode] =
790 					last_victim + p.ofs_unit;
791 			else
792 				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
793 			sm->last_victim[p.gc_mode] %=
794 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
795 			break;
796 		}
797 	}
798 
799 	/* get victim for GC_AT/AT_SSR */
800 	if (is_atgc) {
801 		lookup_victim_by_age(sbi, &p);
802 		release_victim_entry(sbi);
803 	}
804 
805 	if (is_atgc && p.min_segno == NULL_SEGNO &&
806 			sm->elapsed_time < p.age_threshold) {
807 		p.age_threshold = 0;
808 		goto retry;
809 	}
810 
811 	if (p.min_segno != NULL_SEGNO) {
812 got_it:
813 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
814 got_result:
815 		if (p.alloc_mode == LFS) {
816 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
817 			if (gc_type == FG_GC)
818 				sbi->cur_victim_sec = secno;
819 			else
820 				set_bit(secno, dirty_i->victim_secmap);
821 		}
822 		ret = 0;
823 
824 	}
825 out:
826 	if (p.min_segno != NULL_SEGNO)
827 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
828 				sbi->cur_victim_sec,
829 				prefree_segments(sbi), free_segments(sbi));
830 	mutex_unlock(&dirty_i->seglist_lock);
831 
832 	return ret;
833 }
834 
835 static const struct victim_selection default_v_ops = {
836 	.get_victim = get_victim_by_default,
837 };
838 
839 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
840 {
841 	struct inode_entry *ie;
842 
843 	ie = radix_tree_lookup(&gc_list->iroot, ino);
844 	if (ie)
845 		return ie->inode;
846 	return NULL;
847 }
848 
849 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
850 {
851 	struct inode_entry *new_ie;
852 
853 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
854 		iput(inode);
855 		return;
856 	}
857 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab,
858 					GFP_NOFS, true, NULL);
859 	new_ie->inode = inode;
860 
861 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
862 	list_add_tail(&new_ie->list, &gc_list->ilist);
863 }
864 
865 static void put_gc_inode(struct gc_inode_list *gc_list)
866 {
867 	struct inode_entry *ie, *next_ie;
868 
869 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
870 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
871 		iput(ie->inode);
872 		list_del(&ie->list);
873 		kmem_cache_free(f2fs_inode_entry_slab, ie);
874 	}
875 }
876 
877 static int check_valid_map(struct f2fs_sb_info *sbi,
878 				unsigned int segno, int offset)
879 {
880 	struct sit_info *sit_i = SIT_I(sbi);
881 	struct seg_entry *sentry;
882 	int ret;
883 
884 	down_read(&sit_i->sentry_lock);
885 	sentry = get_seg_entry(sbi, segno);
886 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
887 	up_read(&sit_i->sentry_lock);
888 	return ret;
889 }
890 
891 /*
892  * This function compares node address got in summary with that in NAT.
893  * On validity, copy that node with cold status, otherwise (invalid node)
894  * ignore that.
895  */
896 static int gc_node_segment(struct f2fs_sb_info *sbi,
897 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
898 {
899 	struct f2fs_summary *entry;
900 	block_t start_addr;
901 	int off;
902 	int phase = 0;
903 	bool fggc = (gc_type == FG_GC);
904 	int submitted = 0;
905 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
906 
907 	start_addr = START_BLOCK(sbi, segno);
908 
909 next_step:
910 	entry = sum;
911 
912 	if (fggc && phase == 2)
913 		atomic_inc(&sbi->wb_sync_req[NODE]);
914 
915 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
916 		nid_t nid = le32_to_cpu(entry->nid);
917 		struct page *node_page;
918 		struct node_info ni;
919 		int err;
920 
921 		/* stop BG_GC if there is not enough free sections. */
922 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
923 			return submitted;
924 
925 		if (check_valid_map(sbi, segno, off) == 0)
926 			continue;
927 
928 		if (phase == 0) {
929 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
930 							META_NAT, true);
931 			continue;
932 		}
933 
934 		if (phase == 1) {
935 			f2fs_ra_node_page(sbi, nid);
936 			continue;
937 		}
938 
939 		/* phase == 2 */
940 		node_page = f2fs_get_node_page(sbi, nid);
941 		if (IS_ERR(node_page))
942 			continue;
943 
944 		/* block may become invalid during f2fs_get_node_page */
945 		if (check_valid_map(sbi, segno, off) == 0) {
946 			f2fs_put_page(node_page, 1);
947 			continue;
948 		}
949 
950 		if (f2fs_get_node_info(sbi, nid, &ni)) {
951 			f2fs_put_page(node_page, 1);
952 			continue;
953 		}
954 
955 		if (ni.blk_addr != start_addr + off) {
956 			f2fs_put_page(node_page, 1);
957 			continue;
958 		}
959 
960 		err = f2fs_move_node_page(node_page, gc_type);
961 		if (!err && gc_type == FG_GC)
962 			submitted++;
963 		stat_inc_node_blk_count(sbi, 1, gc_type);
964 	}
965 
966 	if (++phase < 3)
967 		goto next_step;
968 
969 	if (fggc)
970 		atomic_dec(&sbi->wb_sync_req[NODE]);
971 	return submitted;
972 }
973 
974 /*
975  * Calculate start block index indicating the given node offset.
976  * Be careful, caller should give this node offset only indicating direct node
977  * blocks. If any node offsets, which point the other types of node blocks such
978  * as indirect or double indirect node blocks, are given, it must be a caller's
979  * bug.
980  */
981 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
982 {
983 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
984 	unsigned int bidx;
985 
986 	if (node_ofs == 0)
987 		return 0;
988 
989 	if (node_ofs <= 2) {
990 		bidx = node_ofs - 1;
991 	} else if (node_ofs <= indirect_blks) {
992 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
993 
994 		bidx = node_ofs - 2 - dec;
995 	} else {
996 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
997 
998 		bidx = node_ofs - 5 - dec;
999 	}
1000 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
1001 }
1002 
1003 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1004 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
1005 {
1006 	struct page *node_page;
1007 	nid_t nid;
1008 	unsigned int ofs_in_node;
1009 	block_t source_blkaddr;
1010 
1011 	nid = le32_to_cpu(sum->nid);
1012 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
1013 
1014 	node_page = f2fs_get_node_page(sbi, nid);
1015 	if (IS_ERR(node_page))
1016 		return false;
1017 
1018 	if (f2fs_get_node_info(sbi, nid, dni)) {
1019 		f2fs_put_page(node_page, 1);
1020 		return false;
1021 	}
1022 
1023 	if (sum->version != dni->version) {
1024 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
1025 			  __func__);
1026 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1027 	}
1028 
1029 	*nofs = ofs_of_node(node_page);
1030 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
1031 	f2fs_put_page(node_page, 1);
1032 
1033 	if (source_blkaddr != blkaddr) {
1034 #ifdef CONFIG_F2FS_CHECK_FS
1035 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
1036 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
1037 
1038 		if (unlikely(check_valid_map(sbi, segno, offset))) {
1039 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
1040 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u",
1041 					 blkaddr, source_blkaddr, segno);
1042 				f2fs_bug_on(sbi, 1);
1043 			}
1044 		}
1045 #endif
1046 		return false;
1047 	}
1048 	return true;
1049 }
1050 
1051 static int ra_data_block(struct inode *inode, pgoff_t index)
1052 {
1053 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1054 	struct address_space *mapping = inode->i_mapping;
1055 	struct dnode_of_data dn;
1056 	struct page *page;
1057 	struct extent_info ei = {0, 0, 0};
1058 	struct f2fs_io_info fio = {
1059 		.sbi = sbi,
1060 		.ino = inode->i_ino,
1061 		.type = DATA,
1062 		.temp = COLD,
1063 		.op = REQ_OP_READ,
1064 		.op_flags = 0,
1065 		.encrypted_page = NULL,
1066 		.in_list = false,
1067 		.retry = false,
1068 	};
1069 	int err;
1070 
1071 	page = f2fs_grab_cache_page(mapping, index, true);
1072 	if (!page)
1073 		return -ENOMEM;
1074 
1075 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
1076 		dn.data_blkaddr = ei.blk + index - ei.fofs;
1077 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1078 						DATA_GENERIC_ENHANCE_READ))) {
1079 			err = -EFSCORRUPTED;
1080 			goto put_page;
1081 		}
1082 		goto got_it;
1083 	}
1084 
1085 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1086 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
1087 	if (err)
1088 		goto put_page;
1089 	f2fs_put_dnode(&dn);
1090 
1091 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
1092 		err = -ENOENT;
1093 		goto put_page;
1094 	}
1095 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
1096 						DATA_GENERIC_ENHANCE))) {
1097 		err = -EFSCORRUPTED;
1098 		goto put_page;
1099 	}
1100 got_it:
1101 	/* read page */
1102 	fio.page = page;
1103 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1104 
1105 	/*
1106 	 * don't cache encrypted data into meta inode until previous dirty
1107 	 * data were writebacked to avoid racing between GC and flush.
1108 	 */
1109 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1110 
1111 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1112 
1113 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
1114 					dn.data_blkaddr,
1115 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
1116 	if (!fio.encrypted_page) {
1117 		err = -ENOMEM;
1118 		goto put_page;
1119 	}
1120 
1121 	err = f2fs_submit_page_bio(&fio);
1122 	if (err)
1123 		goto put_encrypted_page;
1124 	f2fs_put_page(fio.encrypted_page, 0);
1125 	f2fs_put_page(page, 1);
1126 
1127 	f2fs_update_iostat(sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
1128 	f2fs_update_iostat(sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1129 
1130 	return 0;
1131 put_encrypted_page:
1132 	f2fs_put_page(fio.encrypted_page, 1);
1133 put_page:
1134 	f2fs_put_page(page, 1);
1135 	return err;
1136 }
1137 
1138 /*
1139  * Move data block via META_MAPPING while keeping locked data page.
1140  * This can be used to move blocks, aka LBAs, directly on disk.
1141  */
1142 static int move_data_block(struct inode *inode, block_t bidx,
1143 				int gc_type, unsigned int segno, int off)
1144 {
1145 	struct f2fs_io_info fio = {
1146 		.sbi = F2FS_I_SB(inode),
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 	struct dnode_of_data dn;
1157 	struct f2fs_summary sum;
1158 	struct node_info ni;
1159 	struct page *page, *mpage;
1160 	block_t newaddr;
1161 	int err = 0;
1162 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
1163 	int type = fio.sbi->am.atgc_enabled && (gc_type == BG_GC) &&
1164 				(fio.sbi->gc_mode != GC_URGENT_HIGH) ?
1165 				CURSEG_ALL_DATA_ATGC : CURSEG_COLD_DATA;
1166 
1167 	/* do not read out */
1168 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
1169 	if (!page)
1170 		return -ENOMEM;
1171 
1172 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1173 		err = -ENOENT;
1174 		goto out;
1175 	}
1176 
1177 	if (f2fs_is_atomic_file(inode)) {
1178 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
1179 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
1180 		err = -EAGAIN;
1181 		goto out;
1182 	}
1183 
1184 	if (f2fs_is_pinned_file(inode)) {
1185 		f2fs_pin_file_control(inode, true);
1186 		err = -EAGAIN;
1187 		goto out;
1188 	}
1189 
1190 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1191 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
1192 	if (err)
1193 		goto out;
1194 
1195 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
1196 		ClearPageUptodate(page);
1197 		err = -ENOENT;
1198 		goto put_out;
1199 	}
1200 
1201 	/*
1202 	 * don't cache encrypted data into meta inode until previous dirty
1203 	 * data were writebacked to avoid racing between GC and flush.
1204 	 */
1205 	f2fs_wait_on_page_writeback(page, DATA, true, true);
1206 
1207 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
1208 
1209 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
1210 	if (err)
1211 		goto put_out;
1212 
1213 	/* read page */
1214 	fio.page = page;
1215 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
1216 
1217 	if (lfs_mode)
1218 		down_write(&fio.sbi->io_order_lock);
1219 
1220 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
1221 					fio.old_blkaddr, false);
1222 	if (!mpage) {
1223 		err = -ENOMEM;
1224 		goto up_out;
1225 	}
1226 
1227 	fio.encrypted_page = mpage;
1228 
1229 	/* read source block in mpage */
1230 	if (!PageUptodate(mpage)) {
1231 		err = f2fs_submit_page_bio(&fio);
1232 		if (err) {
1233 			f2fs_put_page(mpage, 1);
1234 			goto up_out;
1235 		}
1236 
1237 		f2fs_update_iostat(fio.sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
1238 		f2fs_update_iostat(fio.sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
1239 
1240 		lock_page(mpage);
1241 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
1242 						!PageUptodate(mpage))) {
1243 			err = -EIO;
1244 			f2fs_put_page(mpage, 1);
1245 			goto up_out;
1246 		}
1247 	}
1248 
1249 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
1250 
1251 	/* allocate block address */
1252 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
1253 				&sum, type, NULL);
1254 
1255 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
1256 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
1257 	if (!fio.encrypted_page) {
1258 		err = -ENOMEM;
1259 		f2fs_put_page(mpage, 1);
1260 		goto recover_block;
1261 	}
1262 
1263 	/* write target block */
1264 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
1265 	memcpy(page_address(fio.encrypted_page),
1266 				page_address(mpage), PAGE_SIZE);
1267 	f2fs_put_page(mpage, 1);
1268 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
1269 				fio.old_blkaddr, fio.old_blkaddr);
1270 	f2fs_invalidate_compress_page(fio.sbi, fio.old_blkaddr);
1271 
1272 	set_page_dirty(fio.encrypted_page);
1273 	if (clear_page_dirty_for_io(fio.encrypted_page))
1274 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
1275 
1276 	set_page_writeback(fio.encrypted_page);
1277 	ClearPageError(page);
1278 
1279 	fio.op = REQ_OP_WRITE;
1280 	fio.op_flags = REQ_SYNC;
1281 	fio.new_blkaddr = newaddr;
1282 	f2fs_submit_page_write(&fio);
1283 	if (fio.retry) {
1284 		err = -EAGAIN;
1285 		if (PageWriteback(fio.encrypted_page))
1286 			end_page_writeback(fio.encrypted_page);
1287 		goto put_page_out;
1288 	}
1289 
1290 	f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
1291 
1292 	f2fs_update_data_blkaddr(&dn, newaddr);
1293 	set_inode_flag(inode, FI_APPEND_WRITE);
1294 	if (page->index == 0)
1295 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
1296 put_page_out:
1297 	f2fs_put_page(fio.encrypted_page, 1);
1298 recover_block:
1299 	if (err)
1300 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
1301 							true, true, true);
1302 up_out:
1303 	if (lfs_mode)
1304 		up_write(&fio.sbi->io_order_lock);
1305 put_out:
1306 	f2fs_put_dnode(&dn);
1307 out:
1308 	f2fs_put_page(page, 1);
1309 	return err;
1310 }
1311 
1312 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
1313 							unsigned int segno, int off)
1314 {
1315 	struct page *page;
1316 	int err = 0;
1317 
1318 	page = f2fs_get_lock_data_page(inode, bidx, true);
1319 	if (IS_ERR(page))
1320 		return PTR_ERR(page);
1321 
1322 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
1323 		err = -ENOENT;
1324 		goto out;
1325 	}
1326 
1327 	if (f2fs_is_atomic_file(inode)) {
1328 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
1329 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
1330 		err = -EAGAIN;
1331 		goto out;
1332 	}
1333 	if (f2fs_is_pinned_file(inode)) {
1334 		if (gc_type == FG_GC)
1335 			f2fs_pin_file_control(inode, true);
1336 		err = -EAGAIN;
1337 		goto out;
1338 	}
1339 
1340 	if (gc_type == BG_GC) {
1341 		if (PageWriteback(page)) {
1342 			err = -EAGAIN;
1343 			goto out;
1344 		}
1345 		set_page_dirty(page);
1346 		set_page_private_gcing(page);
1347 	} else {
1348 		struct f2fs_io_info fio = {
1349 			.sbi = F2FS_I_SB(inode),
1350 			.ino = inode->i_ino,
1351 			.type = DATA,
1352 			.temp = COLD,
1353 			.op = REQ_OP_WRITE,
1354 			.op_flags = REQ_SYNC,
1355 			.old_blkaddr = NULL_ADDR,
1356 			.page = page,
1357 			.encrypted_page = NULL,
1358 			.need_lock = LOCK_REQ,
1359 			.io_type = FS_GC_DATA_IO,
1360 		};
1361 		bool is_dirty = PageDirty(page);
1362 
1363 retry:
1364 		f2fs_wait_on_page_writeback(page, DATA, true, true);
1365 
1366 		set_page_dirty(page);
1367 		if (clear_page_dirty_for_io(page)) {
1368 			inode_dec_dirty_pages(inode);
1369 			f2fs_remove_dirty_inode(inode);
1370 		}
1371 
1372 		set_page_private_gcing(page);
1373 
1374 		err = f2fs_do_write_data_page(&fio);
1375 		if (err) {
1376 			clear_page_private_gcing(page);
1377 			if (err == -ENOMEM) {
1378 				memalloc_retry_wait(GFP_NOFS);
1379 				goto retry;
1380 			}
1381 			if (is_dirty)
1382 				set_page_dirty(page);
1383 		}
1384 	}
1385 out:
1386 	f2fs_put_page(page, 1);
1387 	return err;
1388 }
1389 
1390 /*
1391  * This function tries to get parent node of victim data block, and identifies
1392  * data block validity. If the block is valid, copy that with cold status and
1393  * modify parent node.
1394  * If the parent node is not valid or the data block address is different,
1395  * the victim data block is ignored.
1396  */
1397 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1398 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type,
1399 		bool force_migrate)
1400 {
1401 	struct super_block *sb = sbi->sb;
1402 	struct f2fs_summary *entry;
1403 	block_t start_addr;
1404 	int off;
1405 	int phase = 0;
1406 	int submitted = 0;
1407 	unsigned int usable_blks_in_seg = f2fs_usable_blks_in_seg(sbi, segno);
1408 
1409 	start_addr = START_BLOCK(sbi, segno);
1410 
1411 next_step:
1412 	entry = sum;
1413 
1414 	for (off = 0; off < usable_blks_in_seg; off++, entry++) {
1415 		struct page *data_page;
1416 		struct inode *inode;
1417 		struct node_info dni; /* dnode info for the data */
1418 		unsigned int ofs_in_node, nofs;
1419 		block_t start_bidx;
1420 		nid_t nid = le32_to_cpu(entry->nid);
1421 
1422 		/*
1423 		 * stop BG_GC if there is not enough free sections.
1424 		 * Or, stop GC if the segment becomes fully valid caused by
1425 		 * race condition along with SSR block allocation.
1426 		 */
1427 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1428 			(!force_migrate && get_valid_blocks(sbi, segno, true) ==
1429 							BLKS_PER_SEC(sbi)))
1430 			return submitted;
1431 
1432 		if (check_valid_map(sbi, segno, off) == 0)
1433 			continue;
1434 
1435 		if (phase == 0) {
1436 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1437 							META_NAT, true);
1438 			continue;
1439 		}
1440 
1441 		if (phase == 1) {
1442 			f2fs_ra_node_page(sbi, nid);
1443 			continue;
1444 		}
1445 
1446 		/* Get an inode by ino with checking validity */
1447 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1448 			continue;
1449 
1450 		if (phase == 2) {
1451 			f2fs_ra_node_page(sbi, dni.ino);
1452 			continue;
1453 		}
1454 
1455 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1456 
1457 		if (phase == 3) {
1458 			inode = f2fs_iget(sb, dni.ino);
1459 			if (IS_ERR(inode) || is_bad_inode(inode))
1460 				continue;
1461 
1462 			if (!down_write_trylock(
1463 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1464 				iput(inode);
1465 				sbi->skipped_gc_rwsem++;
1466 				continue;
1467 			}
1468 
1469 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1470 								ofs_in_node;
1471 
1472 			if (f2fs_post_read_required(inode)) {
1473 				int err = ra_data_block(inode, start_bidx);
1474 
1475 				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1476 				if (err) {
1477 					iput(inode);
1478 					continue;
1479 				}
1480 				add_gc_inode(gc_list, inode);
1481 				continue;
1482 			}
1483 
1484 			data_page = f2fs_get_read_data_page(inode,
1485 						start_bidx, REQ_RAHEAD, true);
1486 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1487 			if (IS_ERR(data_page)) {
1488 				iput(inode);
1489 				continue;
1490 			}
1491 
1492 			f2fs_put_page(data_page, 0);
1493 			add_gc_inode(gc_list, inode);
1494 			continue;
1495 		}
1496 
1497 		/* phase 4 */
1498 		inode = find_gc_inode(gc_list, dni.ino);
1499 		if (inode) {
1500 			struct f2fs_inode_info *fi = F2FS_I(inode);
1501 			bool locked = false;
1502 			int err;
1503 
1504 			if (S_ISREG(inode->i_mode)) {
1505 				if (!down_write_trylock(&fi->i_gc_rwsem[READ])) {
1506 					sbi->skipped_gc_rwsem++;
1507 					continue;
1508 				}
1509 				if (!down_write_trylock(
1510 						&fi->i_gc_rwsem[WRITE])) {
1511 					sbi->skipped_gc_rwsem++;
1512 					up_write(&fi->i_gc_rwsem[READ]);
1513 					continue;
1514 				}
1515 				locked = true;
1516 
1517 				/* wait for all inflight aio data */
1518 				inode_dio_wait(inode);
1519 			}
1520 
1521 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1522 								+ ofs_in_node;
1523 			if (f2fs_post_read_required(inode))
1524 				err = move_data_block(inode, start_bidx,
1525 							gc_type, segno, off);
1526 			else
1527 				err = move_data_page(inode, start_bidx, gc_type,
1528 								segno, off);
1529 
1530 			if (!err && (gc_type == FG_GC ||
1531 					f2fs_post_read_required(inode)))
1532 				submitted++;
1533 
1534 			if (locked) {
1535 				up_write(&fi->i_gc_rwsem[WRITE]);
1536 				up_write(&fi->i_gc_rwsem[READ]);
1537 			}
1538 
1539 			stat_inc_data_blk_count(sbi, 1, gc_type);
1540 		}
1541 	}
1542 
1543 	if (++phase < 5)
1544 		goto next_step;
1545 
1546 	return submitted;
1547 }
1548 
1549 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1550 			int gc_type)
1551 {
1552 	struct sit_info *sit_i = SIT_I(sbi);
1553 	int ret;
1554 
1555 	down_write(&sit_i->sentry_lock);
1556 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1557 					      NO_CHECK_TYPE, LFS, 0);
1558 	up_write(&sit_i->sentry_lock);
1559 	return ret;
1560 }
1561 
1562 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1563 				unsigned int start_segno,
1564 				struct gc_inode_list *gc_list, int gc_type,
1565 				bool force_migrate)
1566 {
1567 	struct page *sum_page;
1568 	struct f2fs_summary_block *sum;
1569 	struct blk_plug plug;
1570 	unsigned int segno = start_segno;
1571 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1572 	int seg_freed = 0, migrated = 0;
1573 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1574 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1575 	int submitted = 0;
1576 
1577 	if (__is_large_section(sbi))
1578 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1579 
1580 	/*
1581 	 * zone-capacity can be less than zone-size in zoned devices,
1582 	 * resulting in less than expected usable segments in the zone,
1583 	 * calculate the end segno in the zone which can be garbage collected
1584 	 */
1585 	if (f2fs_sb_has_blkzoned(sbi))
1586 		end_segno -= sbi->segs_per_sec -
1587 					f2fs_usable_segs_in_sec(sbi, segno);
1588 
1589 	sanity_check_seg_type(sbi, get_seg_entry(sbi, segno)->type);
1590 
1591 	/* readahead multi ssa blocks those have contiguous address */
1592 	if (__is_large_section(sbi))
1593 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1594 					end_segno - segno, META_SSA, true);
1595 
1596 	/* reference all summary page */
1597 	while (segno < end_segno) {
1598 		sum_page = f2fs_get_sum_page(sbi, segno++);
1599 		if (IS_ERR(sum_page)) {
1600 			int err = PTR_ERR(sum_page);
1601 
1602 			end_segno = segno - 1;
1603 			for (segno = start_segno; segno < end_segno; segno++) {
1604 				sum_page = find_get_page(META_MAPPING(sbi),
1605 						GET_SUM_BLOCK(sbi, segno));
1606 				f2fs_put_page(sum_page, 0);
1607 				f2fs_put_page(sum_page, 0);
1608 			}
1609 			return err;
1610 		}
1611 		unlock_page(sum_page);
1612 	}
1613 
1614 	blk_start_plug(&plug);
1615 
1616 	for (segno = start_segno; segno < end_segno; segno++) {
1617 
1618 		/* find segment summary of victim */
1619 		sum_page = find_get_page(META_MAPPING(sbi),
1620 					GET_SUM_BLOCK(sbi, segno));
1621 		f2fs_put_page(sum_page, 0);
1622 
1623 		if (get_valid_blocks(sbi, segno, false) == 0)
1624 			goto freed;
1625 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1626 				migrated >= sbi->migration_granularity)
1627 			goto skip;
1628 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1629 			goto skip;
1630 
1631 		sum = page_address(sum_page);
1632 		if (type != GET_SUM_TYPE((&sum->footer))) {
1633 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1634 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1635 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1636 			f2fs_stop_checkpoint(sbi, false);
1637 			goto skip;
1638 		}
1639 
1640 		/*
1641 		 * this is to avoid deadlock:
1642 		 * - lock_page(sum_page)         - f2fs_replace_block
1643 		 *  - check_valid_map()            - down_write(sentry_lock)
1644 		 *   - down_read(sentry_lock)     - change_curseg()
1645 		 *                                  - lock_page(sum_page)
1646 		 */
1647 		if (type == SUM_TYPE_NODE)
1648 			submitted += gc_node_segment(sbi, sum->entries, segno,
1649 								gc_type);
1650 		else
1651 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1652 							segno, gc_type,
1653 							force_migrate);
1654 
1655 		stat_inc_seg_count(sbi, type, gc_type);
1656 		sbi->gc_reclaimed_segs[sbi->gc_mode]++;
1657 		migrated++;
1658 
1659 freed:
1660 		if (gc_type == FG_GC &&
1661 				get_valid_blocks(sbi, segno, false) == 0)
1662 			seg_freed++;
1663 
1664 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1665 			sbi->next_victim_seg[gc_type] = segno + 1;
1666 skip:
1667 		f2fs_put_page(sum_page, 0);
1668 	}
1669 
1670 	if (submitted)
1671 		f2fs_submit_merged_write(sbi,
1672 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1673 
1674 	blk_finish_plug(&plug);
1675 
1676 	stat_inc_call_count(sbi->stat_info);
1677 
1678 	return seg_freed;
1679 }
1680 
1681 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1682 			bool background, bool force, unsigned int segno)
1683 {
1684 	int gc_type = sync ? FG_GC : BG_GC;
1685 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1686 	int ret = 0;
1687 	struct cp_control cpc;
1688 	unsigned int init_segno = segno;
1689 	struct gc_inode_list gc_list = {
1690 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1691 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1692 	};
1693 	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1694 	unsigned long long first_skipped;
1695 	unsigned int skipped_round = 0, round = 0;
1696 
1697 	trace_f2fs_gc_begin(sbi->sb, sync, background,
1698 				get_pages(sbi, F2FS_DIRTY_NODES),
1699 				get_pages(sbi, F2FS_DIRTY_DENTS),
1700 				get_pages(sbi, F2FS_DIRTY_IMETA),
1701 				free_sections(sbi),
1702 				free_segments(sbi),
1703 				reserved_segments(sbi),
1704 				prefree_segments(sbi));
1705 
1706 	cpc.reason = __get_cp_reason(sbi);
1707 	sbi->skipped_gc_rwsem = 0;
1708 	first_skipped = last_skipped;
1709 gc_more:
1710 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1711 		ret = -EINVAL;
1712 		goto stop;
1713 	}
1714 	if (unlikely(f2fs_cp_error(sbi))) {
1715 		ret = -EIO;
1716 		goto stop;
1717 	}
1718 
1719 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1720 		/*
1721 		 * For example, if there are many prefree_segments below given
1722 		 * threshold, we can make them free by checkpoint. Then, we
1723 		 * secure free segments which doesn't need fggc any more.
1724 		 */
1725 		if (prefree_segments(sbi) &&
1726 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1727 			ret = f2fs_write_checkpoint(sbi, &cpc);
1728 			if (ret)
1729 				goto stop;
1730 		}
1731 		if (has_not_enough_free_secs(sbi, 0, 0))
1732 			gc_type = FG_GC;
1733 	}
1734 
1735 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1736 	if (gc_type == BG_GC && !background) {
1737 		ret = -EINVAL;
1738 		goto stop;
1739 	}
1740 	ret = __get_victim(sbi, &segno, gc_type);
1741 	if (ret)
1742 		goto stop;
1743 
1744 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type, force);
1745 	if (gc_type == FG_GC &&
1746 		seg_freed == f2fs_usable_segs_in_sec(sbi, segno))
1747 		sec_freed++;
1748 	total_freed += seg_freed;
1749 
1750 	if (gc_type == FG_GC) {
1751 		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1752 						sbi->skipped_gc_rwsem)
1753 			skipped_round++;
1754 		last_skipped = sbi->skipped_atomic_files[FG_GC];
1755 		round++;
1756 	}
1757 
1758 	if (gc_type == FG_GC)
1759 		sbi->cur_victim_sec = NULL_SEGNO;
1760 
1761 	if (sync)
1762 		goto stop;
1763 
1764 	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1765 		if (skipped_round <= MAX_SKIP_GC_COUNT ||
1766 					skipped_round * 2 < round) {
1767 			segno = NULL_SEGNO;
1768 			goto gc_more;
1769 		}
1770 
1771 		if (first_skipped < last_skipped &&
1772 				(last_skipped - first_skipped) >
1773 						sbi->skipped_gc_rwsem) {
1774 			f2fs_drop_inmem_pages_all(sbi, true);
1775 			segno = NULL_SEGNO;
1776 			goto gc_more;
1777 		}
1778 		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1779 			ret = f2fs_write_checkpoint(sbi, &cpc);
1780 	}
1781 stop:
1782 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1783 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1784 
1785 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1786 				get_pages(sbi, F2FS_DIRTY_NODES),
1787 				get_pages(sbi, F2FS_DIRTY_DENTS),
1788 				get_pages(sbi, F2FS_DIRTY_IMETA),
1789 				free_sections(sbi),
1790 				free_segments(sbi),
1791 				reserved_segments(sbi),
1792 				prefree_segments(sbi));
1793 
1794 	up_write(&sbi->gc_lock);
1795 
1796 	put_gc_inode(&gc_list);
1797 
1798 	if (sync && !ret)
1799 		ret = sec_freed ? 0 : -EAGAIN;
1800 	return ret;
1801 }
1802 
1803 int __init f2fs_create_garbage_collection_cache(void)
1804 {
1805 	victim_entry_slab = f2fs_kmem_cache_create("f2fs_victim_entry",
1806 					sizeof(struct victim_entry));
1807 	if (!victim_entry_slab)
1808 		return -ENOMEM;
1809 	return 0;
1810 }
1811 
1812 void f2fs_destroy_garbage_collection_cache(void)
1813 {
1814 	kmem_cache_destroy(victim_entry_slab);
1815 }
1816 
1817 static void init_atgc_management(struct f2fs_sb_info *sbi)
1818 {
1819 	struct atgc_management *am = &sbi->am;
1820 
1821 	if (test_opt(sbi, ATGC) &&
1822 		SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
1823 		am->atgc_enabled = true;
1824 
1825 	am->root = RB_ROOT_CACHED;
1826 	INIT_LIST_HEAD(&am->victim_list);
1827 	am->victim_count = 0;
1828 
1829 	am->candidate_ratio = DEF_GC_THREAD_CANDIDATE_RATIO;
1830 	am->max_candidate_count = DEF_GC_THREAD_MAX_CANDIDATE_COUNT;
1831 	am->age_weight = DEF_GC_THREAD_AGE_WEIGHT;
1832 	am->age_threshold = DEF_GC_THREAD_AGE_THRESHOLD;
1833 }
1834 
1835 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1836 {
1837 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1838 
1839 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1840 
1841 	/* give warm/cold data area from slower device */
1842 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1843 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1844 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1845 
1846 	init_atgc_management(sbi);
1847 }
1848 
1849 static int free_segment_range(struct f2fs_sb_info *sbi,
1850 				unsigned int secs, bool gc_only)
1851 {
1852 	unsigned int segno, next_inuse, start, end;
1853 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1854 	int gc_mode, gc_type;
1855 	int err = 0;
1856 	int type;
1857 
1858 	/* Force block allocation for GC */
1859 	MAIN_SECS(sbi) -= secs;
1860 	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
1861 	end = MAIN_SEGS(sbi) - 1;
1862 
1863 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1864 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1865 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
1866 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1867 
1868 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1869 		if (sbi->next_victim_seg[gc_type] >= start)
1870 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1871 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1872 
1873 	/* Move out cursegs from the target range */
1874 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_PERSIST_TYPE; type++)
1875 		f2fs_allocate_segment_for_resize(sbi, type, start, end);
1876 
1877 	/* do GC to move out valid blocks in the range */
1878 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1879 		struct gc_inode_list gc_list = {
1880 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1881 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1882 		};
1883 
1884 		do_garbage_collect(sbi, segno, &gc_list, FG_GC, true);
1885 		put_gc_inode(&gc_list);
1886 
1887 		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
1888 			err = -EAGAIN;
1889 			goto out;
1890 		}
1891 		if (fatal_signal_pending(current)) {
1892 			err = -ERESTARTSYS;
1893 			goto out;
1894 		}
1895 	}
1896 	if (gc_only)
1897 		goto out;
1898 
1899 	err = f2fs_write_checkpoint(sbi, &cpc);
1900 	if (err)
1901 		goto out;
1902 
1903 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1904 	if (next_inuse <= end) {
1905 		f2fs_err(sbi, "segno %u should be free but still inuse!",
1906 			 next_inuse);
1907 		f2fs_bug_on(sbi, 1);
1908 	}
1909 out:
1910 	MAIN_SECS(sbi) += secs;
1911 	return err;
1912 }
1913 
1914 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1915 {
1916 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1917 	int section_count;
1918 	int segment_count;
1919 	int segment_count_main;
1920 	long long block_count;
1921 	int segs = secs * sbi->segs_per_sec;
1922 
1923 	down_write(&sbi->sb_lock);
1924 
1925 	section_count = le32_to_cpu(raw_sb->section_count);
1926 	segment_count = le32_to_cpu(raw_sb->segment_count);
1927 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1928 	block_count = le64_to_cpu(raw_sb->block_count);
1929 
1930 	raw_sb->section_count = cpu_to_le32(section_count + secs);
1931 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1932 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1933 	raw_sb->block_count = cpu_to_le64(block_count +
1934 					(long long)segs * sbi->blocks_per_seg);
1935 	if (f2fs_is_multi_device(sbi)) {
1936 		int last_dev = sbi->s_ndevs - 1;
1937 		int dev_segs =
1938 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
1939 
1940 		raw_sb->devs[last_dev].total_segments =
1941 						cpu_to_le32(dev_segs + segs);
1942 	}
1943 
1944 	up_write(&sbi->sb_lock);
1945 }
1946 
1947 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1948 {
1949 	int segs = secs * sbi->segs_per_sec;
1950 	long long blks = (long long)segs * sbi->blocks_per_seg;
1951 	long long user_block_count =
1952 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1953 
1954 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1955 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1956 	MAIN_SECS(sbi) += secs;
1957 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1958 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1959 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
1960 
1961 	if (f2fs_is_multi_device(sbi)) {
1962 		int last_dev = sbi->s_ndevs - 1;
1963 
1964 		FDEV(last_dev).total_segments =
1965 				(int)FDEV(last_dev).total_segments + segs;
1966 		FDEV(last_dev).end_blk =
1967 				(long long)FDEV(last_dev).end_blk + blks;
1968 #ifdef CONFIG_BLK_DEV_ZONED
1969 		FDEV(last_dev).nr_blkz = (int)FDEV(last_dev).nr_blkz +
1970 					(int)(blks >> sbi->log_blocks_per_blkz);
1971 #endif
1972 	}
1973 }
1974 
1975 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1976 {
1977 	__u64 old_block_count, shrunk_blocks;
1978 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1979 	unsigned int secs;
1980 	int err = 0;
1981 	__u32 rem;
1982 
1983 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
1984 	if (block_count > old_block_count)
1985 		return -EINVAL;
1986 
1987 	if (f2fs_is_multi_device(sbi)) {
1988 		int last_dev = sbi->s_ndevs - 1;
1989 		__u64 last_segs = FDEV(last_dev).total_segments;
1990 
1991 		if (block_count + last_segs * sbi->blocks_per_seg <=
1992 								old_block_count)
1993 			return -EINVAL;
1994 	}
1995 
1996 	/* new fs size should align to section size */
1997 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
1998 	if (rem)
1999 		return -EINVAL;
2000 
2001 	if (block_count == old_block_count)
2002 		return 0;
2003 
2004 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
2005 		f2fs_err(sbi, "Should run fsck to repair first.");
2006 		return -EFSCORRUPTED;
2007 	}
2008 
2009 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
2010 		f2fs_err(sbi, "Checkpoint should be enabled.");
2011 		return -EINVAL;
2012 	}
2013 
2014 	shrunk_blocks = old_block_count - block_count;
2015 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
2016 
2017 	/* stop other GC */
2018 	if (!down_write_trylock(&sbi->gc_lock))
2019 		return -EAGAIN;
2020 
2021 	/* stop CP to protect MAIN_SEC in free_segment_range */
2022 	f2fs_lock_op(sbi);
2023 
2024 	spin_lock(&sbi->stat_lock);
2025 	if (shrunk_blocks + valid_user_blocks(sbi) +
2026 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2027 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2028 		err = -ENOSPC;
2029 	spin_unlock(&sbi->stat_lock);
2030 
2031 	if (err)
2032 		goto out_unlock;
2033 
2034 	err = free_segment_range(sbi, secs, true);
2035 
2036 out_unlock:
2037 	f2fs_unlock_op(sbi);
2038 	up_write(&sbi->gc_lock);
2039 	if (err)
2040 		return err;
2041 
2042 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
2043 
2044 	freeze_super(sbi->sb);
2045 	down_write(&sbi->gc_lock);
2046 	down_write(&sbi->cp_global_sem);
2047 
2048 	spin_lock(&sbi->stat_lock);
2049 	if (shrunk_blocks + valid_user_blocks(sbi) +
2050 		sbi->current_reserved_blocks + sbi->unusable_block_count +
2051 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
2052 		err = -ENOSPC;
2053 	else
2054 		sbi->user_block_count -= shrunk_blocks;
2055 	spin_unlock(&sbi->stat_lock);
2056 	if (err)
2057 		goto out_err;
2058 
2059 	err = free_segment_range(sbi, secs, false);
2060 	if (err)
2061 		goto recover_out;
2062 
2063 	update_sb_metadata(sbi, -secs);
2064 
2065 	err = f2fs_commit_super(sbi, false);
2066 	if (err) {
2067 		update_sb_metadata(sbi, secs);
2068 		goto recover_out;
2069 	}
2070 
2071 	update_fs_metadata(sbi, -secs);
2072 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2073 	set_sbi_flag(sbi, SBI_IS_DIRTY);
2074 
2075 	err = f2fs_write_checkpoint(sbi, &cpc);
2076 	if (err) {
2077 		update_fs_metadata(sbi, secs);
2078 		update_sb_metadata(sbi, secs);
2079 		f2fs_commit_super(sbi, false);
2080 	}
2081 recover_out:
2082 	if (err) {
2083 		set_sbi_flag(sbi, SBI_NEED_FSCK);
2084 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
2085 
2086 		spin_lock(&sbi->stat_lock);
2087 		sbi->user_block_count += shrunk_blocks;
2088 		spin_unlock(&sbi->stat_lock);
2089 	}
2090 out_err:
2091 	up_write(&sbi->cp_global_sem);
2092 	up_write(&sbi->gc_lock);
2093 	thaw_super(sbi->sb);
2094 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
2095 	return err;
2096 }
2097