xref: /openbmc/linux/fs/f2fs/gc.c (revision e2d413f9)
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 int gc_thread_func(void *data)
25 {
26 	struct f2fs_sb_info *sbi = data;
27 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
28 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
29 	unsigned int wait_ms;
30 
31 	wait_ms = gc_th->min_sleep_time;
32 
33 	set_freezable();
34 	do {
35 		bool sync_mode;
36 
37 		wait_event_interruptible_timeout(*wq,
38 				kthread_should_stop() || freezing(current) ||
39 				gc_th->gc_wake,
40 				msecs_to_jiffies(wait_ms));
41 
42 		/* give it a try one time */
43 		if (gc_th->gc_wake)
44 			gc_th->gc_wake = 0;
45 
46 		if (try_to_freeze()) {
47 			stat_other_skip_bggc_count(sbi);
48 			continue;
49 		}
50 		if (kthread_should_stop())
51 			break;
52 
53 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
54 			increase_sleep_time(gc_th, &wait_ms);
55 			stat_other_skip_bggc_count(sbi);
56 			continue;
57 		}
58 
59 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
60 			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
61 			f2fs_stop_checkpoint(sbi, false);
62 		}
63 
64 		if (!sb_start_write_trylock(sbi->sb)) {
65 			stat_other_skip_bggc_count(sbi);
66 			continue;
67 		}
68 
69 		/*
70 		 * [GC triggering condition]
71 		 * 0. GC is not conducted currently.
72 		 * 1. There are enough dirty segments.
73 		 * 2. IO subsystem is idle by checking the # of writeback pages.
74 		 * 3. IO subsystem is idle by checking the # of requests in
75 		 *    bdev's request list.
76 		 *
77 		 * Note) We have to avoid triggering GCs frequently.
78 		 * Because it is possible that some segments can be
79 		 * invalidated soon after by user update or deletion.
80 		 * So, I'd like to wait some time to collect dirty segments.
81 		 */
82 		if (sbi->gc_mode == GC_URGENT) {
83 			wait_ms = gc_th->urgent_sleep_time;
84 			down_write(&sbi->gc_lock);
85 			goto do_gc;
86 		}
87 
88 		if (!down_write_trylock(&sbi->gc_lock)) {
89 			stat_other_skip_bggc_count(sbi);
90 			goto next;
91 		}
92 
93 		if (!is_idle(sbi, GC_TIME)) {
94 			increase_sleep_time(gc_th, &wait_ms);
95 			up_write(&sbi->gc_lock);
96 			stat_io_skip_bggc_count(sbi);
97 			goto next;
98 		}
99 
100 		if (has_enough_invalid_blocks(sbi))
101 			decrease_sleep_time(gc_th, &wait_ms);
102 		else
103 			increase_sleep_time(gc_th, &wait_ms);
104 do_gc:
105 		stat_inc_bggc_count(sbi->stat_info);
106 
107 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
108 
109 		/* if return value is not zero, no victim was selected */
110 		if (f2fs_gc(sbi, sync_mode, true, NULL_SEGNO))
111 			wait_ms = gc_th->no_gc_sleep_time;
112 
113 		trace_f2fs_background_gc(sbi->sb, wait_ms,
114 				prefree_segments(sbi), free_segments(sbi));
115 
116 		/* balancing f2fs's metadata periodically */
117 		f2fs_balance_fs_bg(sbi, true);
118 next:
119 		sb_end_write(sbi->sb);
120 
121 	} while (!kthread_should_stop());
122 	return 0;
123 }
124 
125 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
126 {
127 	struct f2fs_gc_kthread *gc_th;
128 	dev_t dev = sbi->sb->s_bdev->bd_dev;
129 	int err = 0;
130 
131 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
132 	if (!gc_th) {
133 		err = -ENOMEM;
134 		goto out;
135 	}
136 
137 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
138 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
139 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
140 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
141 
142 	gc_th->gc_wake= 0;
143 
144 	sbi->gc_thread = gc_th;
145 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
146 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
147 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
148 	if (IS_ERR(gc_th->f2fs_gc_task)) {
149 		err = PTR_ERR(gc_th->f2fs_gc_task);
150 		kvfree(gc_th);
151 		sbi->gc_thread = NULL;
152 	}
153 out:
154 	return err;
155 }
156 
157 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
158 {
159 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
160 	if (!gc_th)
161 		return;
162 	kthread_stop(gc_th->f2fs_gc_task);
163 	kvfree(gc_th);
164 	sbi->gc_thread = NULL;
165 }
166 
167 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
168 {
169 	int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
170 
171 	switch (sbi->gc_mode) {
172 	case GC_IDLE_CB:
173 		gc_mode = GC_CB;
174 		break;
175 	case GC_IDLE_GREEDY:
176 	case GC_URGENT:
177 		gc_mode = GC_GREEDY;
178 		break;
179 	}
180 	return gc_mode;
181 }
182 
183 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
184 			int type, struct victim_sel_policy *p)
185 {
186 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
187 
188 	if (p->alloc_mode == SSR) {
189 		p->gc_mode = GC_GREEDY;
190 		p->dirty_segmap = dirty_i->dirty_segmap[type];
191 		p->max_search = dirty_i->nr_dirty[type];
192 		p->ofs_unit = 1;
193 	} else {
194 		p->gc_mode = select_gc_type(sbi, gc_type);
195 		p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
196 		p->max_search = dirty_i->nr_dirty[DIRTY];
197 		p->ofs_unit = sbi->segs_per_sec;
198 	}
199 
200 	/*
201 	 * adjust candidates range, should select all dirty segments for
202 	 * foreground GC and urgent GC cases.
203 	 */
204 	if (gc_type != FG_GC &&
205 			(sbi->gc_mode != GC_URGENT) &&
206 			p->max_search > sbi->max_victim_search)
207 		p->max_search = sbi->max_victim_search;
208 
209 	/* let's select beginning hot/small space first in no_heap mode*/
210 	if (test_opt(sbi, NOHEAP) &&
211 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
212 		p->offset = 0;
213 	else
214 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
215 }
216 
217 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
218 				struct victim_sel_policy *p)
219 {
220 	/* SSR allocates in a segment unit */
221 	if (p->alloc_mode == SSR)
222 		return sbi->blocks_per_seg;
223 	if (p->gc_mode == GC_GREEDY)
224 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
225 	else if (p->gc_mode == GC_CB)
226 		return UINT_MAX;
227 	else /* No other gc_mode */
228 		return 0;
229 }
230 
231 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
232 {
233 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
234 	unsigned int secno;
235 
236 	/*
237 	 * If the gc_type is FG_GC, we can select victim segments
238 	 * selected by background GC before.
239 	 * Those segments guarantee they have small valid blocks.
240 	 */
241 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
242 		if (sec_usage_check(sbi, secno))
243 			continue;
244 		clear_bit(secno, dirty_i->victim_secmap);
245 		return GET_SEG_FROM_SEC(sbi, secno);
246 	}
247 	return NULL_SEGNO;
248 }
249 
250 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
251 {
252 	struct sit_info *sit_i = SIT_I(sbi);
253 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
254 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
255 	unsigned long long mtime = 0;
256 	unsigned int vblocks;
257 	unsigned char age = 0;
258 	unsigned char u;
259 	unsigned int i;
260 
261 	for (i = 0; i < sbi->segs_per_sec; i++)
262 		mtime += get_seg_entry(sbi, start + i)->mtime;
263 	vblocks = get_valid_blocks(sbi, segno, true);
264 
265 	mtime = div_u64(mtime, sbi->segs_per_sec);
266 	vblocks = div_u64(vblocks, sbi->segs_per_sec);
267 
268 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
269 
270 	/* Handle if the system time has changed by the user */
271 	if (mtime < sit_i->min_mtime)
272 		sit_i->min_mtime = mtime;
273 	if (mtime > sit_i->max_mtime)
274 		sit_i->max_mtime = mtime;
275 	if (sit_i->max_mtime != sit_i->min_mtime)
276 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
277 				sit_i->max_mtime - sit_i->min_mtime);
278 
279 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
280 }
281 
282 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
283 			unsigned int segno, struct victim_sel_policy *p)
284 {
285 	if (p->alloc_mode == SSR)
286 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
287 
288 	/* alloc_mode == LFS */
289 	if (p->gc_mode == GC_GREEDY)
290 		return get_valid_blocks(sbi, segno, true);
291 	else
292 		return get_cb_cost(sbi, segno);
293 }
294 
295 static unsigned int count_bits(const unsigned long *addr,
296 				unsigned int offset, unsigned int len)
297 {
298 	unsigned int end = offset + len, sum = 0;
299 
300 	while (offset < end) {
301 		if (test_bit(offset++, addr))
302 			++sum;
303 	}
304 	return sum;
305 }
306 
307 /*
308  * This function is called from two paths.
309  * One is garbage collection and the other is SSR segment selection.
310  * When it is called during GC, it just gets a victim segment
311  * and it does not remove it from dirty seglist.
312  * When it is called from SSR segment selection, it finds a segment
313  * which has minimum valid blocks and removes it from dirty seglist.
314  */
315 static int get_victim_by_default(struct f2fs_sb_info *sbi,
316 		unsigned int *result, int gc_type, int type, char alloc_mode)
317 {
318 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
319 	struct sit_info *sm = SIT_I(sbi);
320 	struct victim_sel_policy p;
321 	unsigned int secno, last_victim;
322 	unsigned int last_segment;
323 	unsigned int nsearched = 0;
324 
325 	mutex_lock(&dirty_i->seglist_lock);
326 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
327 
328 	p.alloc_mode = alloc_mode;
329 	select_policy(sbi, gc_type, type, &p);
330 
331 	p.min_segno = NULL_SEGNO;
332 	p.min_cost = get_max_cost(sbi, &p);
333 
334 	if (*result != NULL_SEGNO) {
335 		if (get_valid_blocks(sbi, *result, false) &&
336 			!sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
337 			p.min_segno = *result;
338 		goto out;
339 	}
340 
341 	if (p.max_search == 0)
342 		goto out;
343 
344 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
345 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
346 			p.min_segno = sbi->next_victim_seg[BG_GC];
347 			*result = p.min_segno;
348 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
349 			goto got_result;
350 		}
351 		if (gc_type == FG_GC &&
352 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
353 			p.min_segno = sbi->next_victim_seg[FG_GC];
354 			*result = p.min_segno;
355 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
356 			goto got_result;
357 		}
358 	}
359 
360 	last_victim = sm->last_victim[p.gc_mode];
361 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
362 		p.min_segno = check_bg_victims(sbi);
363 		if (p.min_segno != NULL_SEGNO)
364 			goto got_it;
365 	}
366 
367 	while (1) {
368 		unsigned long cost;
369 		unsigned int segno;
370 
371 		segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
372 		if (segno >= last_segment) {
373 			if (sm->last_victim[p.gc_mode]) {
374 				last_segment =
375 					sm->last_victim[p.gc_mode];
376 				sm->last_victim[p.gc_mode] = 0;
377 				p.offset = 0;
378 				continue;
379 			}
380 			break;
381 		}
382 
383 		p.offset = segno + p.ofs_unit;
384 		if (p.ofs_unit > 1) {
385 			p.offset -= segno % p.ofs_unit;
386 			nsearched += count_bits(p.dirty_segmap,
387 						p.offset - p.ofs_unit,
388 						p.ofs_unit);
389 		} else {
390 			nsearched++;
391 		}
392 
393 #ifdef CONFIG_F2FS_CHECK_FS
394 		/*
395 		 * skip selecting the invalid segno (that is failed due to block
396 		 * validity check failure during GC) to avoid endless GC loop in
397 		 * such cases.
398 		 */
399 		if (test_bit(segno, sm->invalid_segmap))
400 			goto next;
401 #endif
402 
403 		secno = GET_SEC_FROM_SEG(sbi, segno);
404 
405 		if (sec_usage_check(sbi, secno))
406 			goto next;
407 		/* Don't touch checkpointed data */
408 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
409 					get_ckpt_valid_blocks(sbi, segno) &&
410 					p.alloc_mode != SSR))
411 			goto next;
412 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
413 			goto next;
414 
415 		cost = get_gc_cost(sbi, segno, &p);
416 
417 		if (p.min_cost > cost) {
418 			p.min_segno = segno;
419 			p.min_cost = cost;
420 		}
421 next:
422 		if (nsearched >= p.max_search) {
423 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
424 				sm->last_victim[p.gc_mode] = last_victim + 1;
425 			else
426 				sm->last_victim[p.gc_mode] = segno + 1;
427 			sm->last_victim[p.gc_mode] %=
428 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
429 			break;
430 		}
431 	}
432 	if (p.min_segno != NULL_SEGNO) {
433 got_it:
434 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
435 got_result:
436 		if (p.alloc_mode == LFS) {
437 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
438 			if (gc_type == FG_GC)
439 				sbi->cur_victim_sec = secno;
440 			else
441 				set_bit(secno, dirty_i->victim_secmap);
442 		}
443 
444 	}
445 out:
446 	if (p.min_segno != NULL_SEGNO)
447 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
448 				sbi->cur_victim_sec,
449 				prefree_segments(sbi), free_segments(sbi));
450 	mutex_unlock(&dirty_i->seglist_lock);
451 
452 	return (p.min_segno == NULL_SEGNO) ? 0 : 1;
453 }
454 
455 static const struct victim_selection default_v_ops = {
456 	.get_victim = get_victim_by_default,
457 };
458 
459 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
460 {
461 	struct inode_entry *ie;
462 
463 	ie = radix_tree_lookup(&gc_list->iroot, ino);
464 	if (ie)
465 		return ie->inode;
466 	return NULL;
467 }
468 
469 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
470 {
471 	struct inode_entry *new_ie;
472 
473 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
474 		iput(inode);
475 		return;
476 	}
477 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab, GFP_NOFS);
478 	new_ie->inode = inode;
479 
480 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
481 	list_add_tail(&new_ie->list, &gc_list->ilist);
482 }
483 
484 static void put_gc_inode(struct gc_inode_list *gc_list)
485 {
486 	struct inode_entry *ie, *next_ie;
487 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
488 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
489 		iput(ie->inode);
490 		list_del(&ie->list);
491 		kmem_cache_free(f2fs_inode_entry_slab, ie);
492 	}
493 }
494 
495 static int check_valid_map(struct f2fs_sb_info *sbi,
496 				unsigned int segno, int offset)
497 {
498 	struct sit_info *sit_i = SIT_I(sbi);
499 	struct seg_entry *sentry;
500 	int ret;
501 
502 	down_read(&sit_i->sentry_lock);
503 	sentry = get_seg_entry(sbi, segno);
504 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
505 	up_read(&sit_i->sentry_lock);
506 	return ret;
507 }
508 
509 /*
510  * This function compares node address got in summary with that in NAT.
511  * On validity, copy that node with cold status, otherwise (invalid node)
512  * ignore that.
513  */
514 static int gc_node_segment(struct f2fs_sb_info *sbi,
515 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
516 {
517 	struct f2fs_summary *entry;
518 	block_t start_addr;
519 	int off;
520 	int phase = 0;
521 	bool fggc = (gc_type == FG_GC);
522 	int submitted = 0;
523 
524 	start_addr = START_BLOCK(sbi, segno);
525 
526 next_step:
527 	entry = sum;
528 
529 	if (fggc && phase == 2)
530 		atomic_inc(&sbi->wb_sync_req[NODE]);
531 
532 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
533 		nid_t nid = le32_to_cpu(entry->nid);
534 		struct page *node_page;
535 		struct node_info ni;
536 		int err;
537 
538 		/* stop BG_GC if there is not enough free sections. */
539 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
540 			return submitted;
541 
542 		if (check_valid_map(sbi, segno, off) == 0)
543 			continue;
544 
545 		if (phase == 0) {
546 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
547 							META_NAT, true);
548 			continue;
549 		}
550 
551 		if (phase == 1) {
552 			f2fs_ra_node_page(sbi, nid);
553 			continue;
554 		}
555 
556 		/* phase == 2 */
557 		node_page = f2fs_get_node_page(sbi, nid);
558 		if (IS_ERR(node_page))
559 			continue;
560 
561 		/* block may become invalid during f2fs_get_node_page */
562 		if (check_valid_map(sbi, segno, off) == 0) {
563 			f2fs_put_page(node_page, 1);
564 			continue;
565 		}
566 
567 		if (f2fs_get_node_info(sbi, nid, &ni)) {
568 			f2fs_put_page(node_page, 1);
569 			continue;
570 		}
571 
572 		if (ni.blk_addr != start_addr + off) {
573 			f2fs_put_page(node_page, 1);
574 			continue;
575 		}
576 
577 		err = f2fs_move_node_page(node_page, gc_type);
578 		if (!err && gc_type == FG_GC)
579 			submitted++;
580 		stat_inc_node_blk_count(sbi, 1, gc_type);
581 	}
582 
583 	if (++phase < 3)
584 		goto next_step;
585 
586 	if (fggc)
587 		atomic_dec(&sbi->wb_sync_req[NODE]);
588 	return submitted;
589 }
590 
591 /*
592  * Calculate start block index indicating the given node offset.
593  * Be careful, caller should give this node offset only indicating direct node
594  * blocks. If any node offsets, which point the other types of node blocks such
595  * as indirect or double indirect node blocks, are given, it must be a caller's
596  * bug.
597  */
598 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
599 {
600 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
601 	unsigned int bidx;
602 
603 	if (node_ofs == 0)
604 		return 0;
605 
606 	if (node_ofs <= 2) {
607 		bidx = node_ofs - 1;
608 	} else if (node_ofs <= indirect_blks) {
609 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
610 		bidx = node_ofs - 2 - dec;
611 	} else {
612 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
613 		bidx = node_ofs - 5 - dec;
614 	}
615 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
616 }
617 
618 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
619 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
620 {
621 	struct page *node_page;
622 	nid_t nid;
623 	unsigned int ofs_in_node;
624 	block_t source_blkaddr;
625 
626 	nid = le32_to_cpu(sum->nid);
627 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
628 
629 	node_page = f2fs_get_node_page(sbi, nid);
630 	if (IS_ERR(node_page))
631 		return false;
632 
633 	if (f2fs_get_node_info(sbi, nid, dni)) {
634 		f2fs_put_page(node_page, 1);
635 		return false;
636 	}
637 
638 	if (sum->version != dni->version) {
639 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
640 			  __func__);
641 		set_sbi_flag(sbi, SBI_NEED_FSCK);
642 	}
643 
644 	*nofs = ofs_of_node(node_page);
645 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
646 	f2fs_put_page(node_page, 1);
647 
648 	if (source_blkaddr != blkaddr) {
649 #ifdef CONFIG_F2FS_CHECK_FS
650 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
651 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
652 
653 		if (unlikely(check_valid_map(sbi, segno, offset))) {
654 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
655 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u\n",
656 						blkaddr, source_blkaddr, segno);
657 				f2fs_bug_on(sbi, 1);
658 			}
659 		}
660 #endif
661 		return false;
662 	}
663 	return true;
664 }
665 
666 static int ra_data_block(struct inode *inode, pgoff_t index)
667 {
668 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
669 	struct address_space *mapping = inode->i_mapping;
670 	struct dnode_of_data dn;
671 	struct page *page;
672 	struct extent_info ei = {0, 0, 0};
673 	struct f2fs_io_info fio = {
674 		.sbi = sbi,
675 		.ino = inode->i_ino,
676 		.type = DATA,
677 		.temp = COLD,
678 		.op = REQ_OP_READ,
679 		.op_flags = 0,
680 		.encrypted_page = NULL,
681 		.in_list = false,
682 		.retry = false,
683 	};
684 	int err;
685 
686 	page = f2fs_grab_cache_page(mapping, index, true);
687 	if (!page)
688 		return -ENOMEM;
689 
690 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
691 		dn.data_blkaddr = ei.blk + index - ei.fofs;
692 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
693 						DATA_GENERIC_ENHANCE_READ))) {
694 			err = -EFSCORRUPTED;
695 			goto put_page;
696 		}
697 		goto got_it;
698 	}
699 
700 	set_new_dnode(&dn, inode, NULL, NULL, 0);
701 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
702 	if (err)
703 		goto put_page;
704 	f2fs_put_dnode(&dn);
705 
706 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
707 		err = -ENOENT;
708 		goto put_page;
709 	}
710 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
711 						DATA_GENERIC_ENHANCE))) {
712 		err = -EFSCORRUPTED;
713 		goto put_page;
714 	}
715 got_it:
716 	/* read page */
717 	fio.page = page;
718 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
719 
720 	/*
721 	 * don't cache encrypted data into meta inode until previous dirty
722 	 * data were writebacked to avoid racing between GC and flush.
723 	 */
724 	f2fs_wait_on_page_writeback(page, DATA, true, true);
725 
726 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
727 
728 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
729 					dn.data_blkaddr,
730 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
731 	if (!fio.encrypted_page) {
732 		err = -ENOMEM;
733 		goto put_page;
734 	}
735 
736 	err = f2fs_submit_page_bio(&fio);
737 	if (err)
738 		goto put_encrypted_page;
739 	f2fs_put_page(fio.encrypted_page, 0);
740 	f2fs_put_page(page, 1);
741 
742 	f2fs_update_iostat(sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
743 	f2fs_update_iostat(sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
744 
745 	return 0;
746 put_encrypted_page:
747 	f2fs_put_page(fio.encrypted_page, 1);
748 put_page:
749 	f2fs_put_page(page, 1);
750 	return err;
751 }
752 
753 /*
754  * Move data block via META_MAPPING while keeping locked data page.
755  * This can be used to move blocks, aka LBAs, directly on disk.
756  */
757 static int move_data_block(struct inode *inode, block_t bidx,
758 				int gc_type, unsigned int segno, int off)
759 {
760 	struct f2fs_io_info fio = {
761 		.sbi = F2FS_I_SB(inode),
762 		.ino = inode->i_ino,
763 		.type = DATA,
764 		.temp = COLD,
765 		.op = REQ_OP_READ,
766 		.op_flags = 0,
767 		.encrypted_page = NULL,
768 		.in_list = false,
769 		.retry = false,
770 	};
771 	struct dnode_of_data dn;
772 	struct f2fs_summary sum;
773 	struct node_info ni;
774 	struct page *page, *mpage;
775 	block_t newaddr;
776 	int err = 0;
777 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
778 
779 	/* do not read out */
780 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
781 	if (!page)
782 		return -ENOMEM;
783 
784 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
785 		err = -ENOENT;
786 		goto out;
787 	}
788 
789 	if (f2fs_is_atomic_file(inode)) {
790 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
791 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
792 		err = -EAGAIN;
793 		goto out;
794 	}
795 
796 	if (f2fs_is_pinned_file(inode)) {
797 		f2fs_pin_file_control(inode, true);
798 		err = -EAGAIN;
799 		goto out;
800 	}
801 
802 	set_new_dnode(&dn, inode, NULL, NULL, 0);
803 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
804 	if (err)
805 		goto out;
806 
807 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
808 		ClearPageUptodate(page);
809 		err = -ENOENT;
810 		goto put_out;
811 	}
812 
813 	/*
814 	 * don't cache encrypted data into meta inode until previous dirty
815 	 * data were writebacked to avoid racing between GC and flush.
816 	 */
817 	f2fs_wait_on_page_writeback(page, DATA, true, true);
818 
819 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
820 
821 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
822 	if (err)
823 		goto put_out;
824 
825 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
826 
827 	/* read page */
828 	fio.page = page;
829 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
830 
831 	if (lfs_mode)
832 		down_write(&fio.sbi->io_order_lock);
833 
834 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
835 					fio.old_blkaddr, false);
836 	if (!mpage)
837 		goto up_out;
838 
839 	fio.encrypted_page = mpage;
840 
841 	/* read source block in mpage */
842 	if (!PageUptodate(mpage)) {
843 		err = f2fs_submit_page_bio(&fio);
844 		if (err) {
845 			f2fs_put_page(mpage, 1);
846 			goto up_out;
847 		}
848 
849 		f2fs_update_iostat(fio.sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
850 		f2fs_update_iostat(fio.sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
851 
852 		lock_page(mpage);
853 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
854 						!PageUptodate(mpage))) {
855 			err = -EIO;
856 			f2fs_put_page(mpage, 1);
857 			goto up_out;
858 		}
859 	}
860 
861 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
862 					&sum, CURSEG_COLD_DATA, NULL, false);
863 
864 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
865 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
866 	if (!fio.encrypted_page) {
867 		err = -ENOMEM;
868 		f2fs_put_page(mpage, 1);
869 		goto recover_block;
870 	}
871 
872 	/* write target block */
873 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
874 	memcpy(page_address(fio.encrypted_page),
875 				page_address(mpage), PAGE_SIZE);
876 	f2fs_put_page(mpage, 1);
877 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
878 				fio.old_blkaddr, fio.old_blkaddr);
879 
880 	set_page_dirty(fio.encrypted_page);
881 	if (clear_page_dirty_for_io(fio.encrypted_page))
882 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
883 
884 	set_page_writeback(fio.encrypted_page);
885 	ClearPageError(page);
886 
887 	/* allocate block address */
888 	f2fs_wait_on_page_writeback(dn.node_page, NODE, true, true);
889 
890 	fio.op = REQ_OP_WRITE;
891 	fio.op_flags = REQ_SYNC;
892 	fio.new_blkaddr = newaddr;
893 	f2fs_submit_page_write(&fio);
894 	if (fio.retry) {
895 		err = -EAGAIN;
896 		if (PageWriteback(fio.encrypted_page))
897 			end_page_writeback(fio.encrypted_page);
898 		goto put_page_out;
899 	}
900 
901 	f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
902 
903 	f2fs_update_data_blkaddr(&dn, newaddr);
904 	set_inode_flag(inode, FI_APPEND_WRITE);
905 	if (page->index == 0)
906 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
907 put_page_out:
908 	f2fs_put_page(fio.encrypted_page, 1);
909 recover_block:
910 	if (err)
911 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
912 								true, true);
913 up_out:
914 	if (lfs_mode)
915 		up_write(&fio.sbi->io_order_lock);
916 put_out:
917 	f2fs_put_dnode(&dn);
918 out:
919 	f2fs_put_page(page, 1);
920 	return err;
921 }
922 
923 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
924 							unsigned int segno, int off)
925 {
926 	struct page *page;
927 	int err = 0;
928 
929 	page = f2fs_get_lock_data_page(inode, bidx, true);
930 	if (IS_ERR(page))
931 		return PTR_ERR(page);
932 
933 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
934 		err = -ENOENT;
935 		goto out;
936 	}
937 
938 	if (f2fs_is_atomic_file(inode)) {
939 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
940 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
941 		err = -EAGAIN;
942 		goto out;
943 	}
944 	if (f2fs_is_pinned_file(inode)) {
945 		if (gc_type == FG_GC)
946 			f2fs_pin_file_control(inode, true);
947 		err = -EAGAIN;
948 		goto out;
949 	}
950 
951 	if (gc_type == BG_GC) {
952 		if (PageWriteback(page)) {
953 			err = -EAGAIN;
954 			goto out;
955 		}
956 		set_page_dirty(page);
957 		set_cold_data(page);
958 	} else {
959 		struct f2fs_io_info fio = {
960 			.sbi = F2FS_I_SB(inode),
961 			.ino = inode->i_ino,
962 			.type = DATA,
963 			.temp = COLD,
964 			.op = REQ_OP_WRITE,
965 			.op_flags = REQ_SYNC,
966 			.old_blkaddr = NULL_ADDR,
967 			.page = page,
968 			.encrypted_page = NULL,
969 			.need_lock = LOCK_REQ,
970 			.io_type = FS_GC_DATA_IO,
971 		};
972 		bool is_dirty = PageDirty(page);
973 
974 retry:
975 		f2fs_wait_on_page_writeback(page, DATA, true, true);
976 
977 		set_page_dirty(page);
978 		if (clear_page_dirty_for_io(page)) {
979 			inode_dec_dirty_pages(inode);
980 			f2fs_remove_dirty_inode(inode);
981 		}
982 
983 		set_cold_data(page);
984 
985 		err = f2fs_do_write_data_page(&fio);
986 		if (err) {
987 			clear_cold_data(page);
988 			if (err == -ENOMEM) {
989 				congestion_wait(BLK_RW_ASYNC,
990 						DEFAULT_IO_TIMEOUT);
991 				goto retry;
992 			}
993 			if (is_dirty)
994 				set_page_dirty(page);
995 		}
996 	}
997 out:
998 	f2fs_put_page(page, 1);
999 	return err;
1000 }
1001 
1002 /*
1003  * This function tries to get parent node of victim data block, and identifies
1004  * data block validity. If the block is valid, copy that with cold status and
1005  * modify parent node.
1006  * If the parent node is not valid or the data block address is different,
1007  * the victim data block is ignored.
1008  */
1009 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1010 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
1011 {
1012 	struct super_block *sb = sbi->sb;
1013 	struct f2fs_summary *entry;
1014 	block_t start_addr;
1015 	int off;
1016 	int phase = 0;
1017 	int submitted = 0;
1018 
1019 	start_addr = START_BLOCK(sbi, segno);
1020 
1021 next_step:
1022 	entry = sum;
1023 
1024 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
1025 		struct page *data_page;
1026 		struct inode *inode;
1027 		struct node_info dni; /* dnode info for the data */
1028 		unsigned int ofs_in_node, nofs;
1029 		block_t start_bidx;
1030 		nid_t nid = le32_to_cpu(entry->nid);
1031 
1032 		/*
1033 		 * stop BG_GC if there is not enough free sections.
1034 		 * Or, stop GC if the segment becomes fully valid caused by
1035 		 * race condition along with SSR block allocation.
1036 		 */
1037 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1038 				get_valid_blocks(sbi, segno, true) ==
1039 							BLKS_PER_SEC(sbi))
1040 			return submitted;
1041 
1042 		if (check_valid_map(sbi, segno, off) == 0)
1043 			continue;
1044 
1045 		if (phase == 0) {
1046 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1047 							META_NAT, true);
1048 			continue;
1049 		}
1050 
1051 		if (phase == 1) {
1052 			f2fs_ra_node_page(sbi, nid);
1053 			continue;
1054 		}
1055 
1056 		/* Get an inode by ino with checking validity */
1057 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1058 			continue;
1059 
1060 		if (phase == 2) {
1061 			f2fs_ra_node_page(sbi, dni.ino);
1062 			continue;
1063 		}
1064 
1065 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1066 
1067 		if (phase == 3) {
1068 			inode = f2fs_iget(sb, dni.ino);
1069 			if (IS_ERR(inode) || is_bad_inode(inode)) {
1070 				set_sbi_flag(sbi, SBI_NEED_FSCK);
1071 				continue;
1072 			}
1073 
1074 			if (!down_write_trylock(
1075 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1076 				iput(inode);
1077 				sbi->skipped_gc_rwsem++;
1078 				continue;
1079 			}
1080 
1081 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1082 								ofs_in_node;
1083 
1084 			if (f2fs_post_read_required(inode)) {
1085 				int err = ra_data_block(inode, start_bidx);
1086 
1087 				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1088 				if (err) {
1089 					iput(inode);
1090 					continue;
1091 				}
1092 				add_gc_inode(gc_list, inode);
1093 				continue;
1094 			}
1095 
1096 			data_page = f2fs_get_read_data_page(inode,
1097 						start_bidx, REQ_RAHEAD, true);
1098 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1099 			if (IS_ERR(data_page)) {
1100 				iput(inode);
1101 				continue;
1102 			}
1103 
1104 			f2fs_put_page(data_page, 0);
1105 			add_gc_inode(gc_list, inode);
1106 			continue;
1107 		}
1108 
1109 		/* phase 4 */
1110 		inode = find_gc_inode(gc_list, dni.ino);
1111 		if (inode) {
1112 			struct f2fs_inode_info *fi = F2FS_I(inode);
1113 			bool locked = false;
1114 			int err;
1115 
1116 			if (S_ISREG(inode->i_mode)) {
1117 				if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
1118 					continue;
1119 				if (!down_write_trylock(
1120 						&fi->i_gc_rwsem[WRITE])) {
1121 					sbi->skipped_gc_rwsem++;
1122 					up_write(&fi->i_gc_rwsem[READ]);
1123 					continue;
1124 				}
1125 				locked = true;
1126 
1127 				/* wait for all inflight aio data */
1128 				inode_dio_wait(inode);
1129 			}
1130 
1131 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1132 								+ ofs_in_node;
1133 			if (f2fs_post_read_required(inode))
1134 				err = move_data_block(inode, start_bidx,
1135 							gc_type, segno, off);
1136 			else
1137 				err = move_data_page(inode, start_bidx, gc_type,
1138 								segno, off);
1139 
1140 			if (!err && (gc_type == FG_GC ||
1141 					f2fs_post_read_required(inode)))
1142 				submitted++;
1143 
1144 			if (locked) {
1145 				up_write(&fi->i_gc_rwsem[WRITE]);
1146 				up_write(&fi->i_gc_rwsem[READ]);
1147 			}
1148 
1149 			stat_inc_data_blk_count(sbi, 1, gc_type);
1150 		}
1151 	}
1152 
1153 	if (++phase < 5)
1154 		goto next_step;
1155 
1156 	return submitted;
1157 }
1158 
1159 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1160 			int gc_type)
1161 {
1162 	struct sit_info *sit_i = SIT_I(sbi);
1163 	int ret;
1164 
1165 	down_write(&sit_i->sentry_lock);
1166 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1167 					      NO_CHECK_TYPE, LFS);
1168 	up_write(&sit_i->sentry_lock);
1169 	return ret;
1170 }
1171 
1172 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1173 				unsigned int start_segno,
1174 				struct gc_inode_list *gc_list, int gc_type)
1175 {
1176 	struct page *sum_page;
1177 	struct f2fs_summary_block *sum;
1178 	struct blk_plug plug;
1179 	unsigned int segno = start_segno;
1180 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1181 	int seg_freed = 0, migrated = 0;
1182 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1183 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1184 	int submitted = 0;
1185 
1186 	if (__is_large_section(sbi))
1187 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1188 
1189 	/* readahead multi ssa blocks those have contiguous address */
1190 	if (__is_large_section(sbi))
1191 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1192 					end_segno - segno, META_SSA, true);
1193 
1194 	/* reference all summary page */
1195 	while (segno < end_segno) {
1196 		sum_page = f2fs_get_sum_page(sbi, segno++);
1197 		if (IS_ERR(sum_page)) {
1198 			int err = PTR_ERR(sum_page);
1199 
1200 			end_segno = segno - 1;
1201 			for (segno = start_segno; segno < end_segno; segno++) {
1202 				sum_page = find_get_page(META_MAPPING(sbi),
1203 						GET_SUM_BLOCK(sbi, segno));
1204 				f2fs_put_page(sum_page, 0);
1205 				f2fs_put_page(sum_page, 0);
1206 			}
1207 			return err;
1208 		}
1209 		unlock_page(sum_page);
1210 	}
1211 
1212 	blk_start_plug(&plug);
1213 
1214 	for (segno = start_segno; segno < end_segno; segno++) {
1215 
1216 		/* find segment summary of victim */
1217 		sum_page = find_get_page(META_MAPPING(sbi),
1218 					GET_SUM_BLOCK(sbi, segno));
1219 		f2fs_put_page(sum_page, 0);
1220 
1221 		if (get_valid_blocks(sbi, segno, false) == 0)
1222 			goto freed;
1223 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1224 				migrated >= sbi->migration_granularity)
1225 			goto skip;
1226 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1227 			goto skip;
1228 
1229 		sum = page_address(sum_page);
1230 		if (type != GET_SUM_TYPE((&sum->footer))) {
1231 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1232 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1233 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1234 			f2fs_stop_checkpoint(sbi, false);
1235 			goto skip;
1236 		}
1237 
1238 		/*
1239 		 * this is to avoid deadlock:
1240 		 * - lock_page(sum_page)         - f2fs_replace_block
1241 		 *  - check_valid_map()            - down_write(sentry_lock)
1242 		 *   - down_read(sentry_lock)     - change_curseg()
1243 		 *                                  - lock_page(sum_page)
1244 		 */
1245 		if (type == SUM_TYPE_NODE)
1246 			submitted += gc_node_segment(sbi, sum->entries, segno,
1247 								gc_type);
1248 		else
1249 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1250 							segno, gc_type);
1251 
1252 		stat_inc_seg_count(sbi, type, gc_type);
1253 		migrated++;
1254 
1255 freed:
1256 		if (gc_type == FG_GC &&
1257 				get_valid_blocks(sbi, segno, false) == 0)
1258 			seg_freed++;
1259 
1260 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1261 			sbi->next_victim_seg[gc_type] = segno + 1;
1262 skip:
1263 		f2fs_put_page(sum_page, 0);
1264 	}
1265 
1266 	if (submitted)
1267 		f2fs_submit_merged_write(sbi,
1268 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1269 
1270 	blk_finish_plug(&plug);
1271 
1272 	stat_inc_call_count(sbi->stat_info);
1273 
1274 	return seg_freed;
1275 }
1276 
1277 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1278 			bool background, unsigned int segno)
1279 {
1280 	int gc_type = sync ? FG_GC : BG_GC;
1281 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1282 	int ret = 0;
1283 	struct cp_control cpc;
1284 	unsigned int init_segno = segno;
1285 	struct gc_inode_list gc_list = {
1286 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1287 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1288 	};
1289 	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1290 	unsigned long long first_skipped;
1291 	unsigned int skipped_round = 0, round = 0;
1292 
1293 	trace_f2fs_gc_begin(sbi->sb, sync, background,
1294 				get_pages(sbi, F2FS_DIRTY_NODES),
1295 				get_pages(sbi, F2FS_DIRTY_DENTS),
1296 				get_pages(sbi, F2FS_DIRTY_IMETA),
1297 				free_sections(sbi),
1298 				free_segments(sbi),
1299 				reserved_segments(sbi),
1300 				prefree_segments(sbi));
1301 
1302 	cpc.reason = __get_cp_reason(sbi);
1303 	sbi->skipped_gc_rwsem = 0;
1304 	first_skipped = last_skipped;
1305 gc_more:
1306 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1307 		ret = -EINVAL;
1308 		goto stop;
1309 	}
1310 	if (unlikely(f2fs_cp_error(sbi))) {
1311 		ret = -EIO;
1312 		goto stop;
1313 	}
1314 
1315 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1316 		/*
1317 		 * For example, if there are many prefree_segments below given
1318 		 * threshold, we can make them free by checkpoint. Then, we
1319 		 * secure free segments which doesn't need fggc any more.
1320 		 */
1321 		if (prefree_segments(sbi) &&
1322 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1323 			ret = f2fs_write_checkpoint(sbi, &cpc);
1324 			if (ret)
1325 				goto stop;
1326 		}
1327 		if (has_not_enough_free_secs(sbi, 0, 0))
1328 			gc_type = FG_GC;
1329 	}
1330 
1331 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1332 	if (gc_type == BG_GC && !background) {
1333 		ret = -EINVAL;
1334 		goto stop;
1335 	}
1336 	if (!__get_victim(sbi, &segno, gc_type)) {
1337 		ret = -ENODATA;
1338 		goto stop;
1339 	}
1340 
1341 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
1342 	if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
1343 		sec_freed++;
1344 	total_freed += seg_freed;
1345 
1346 	if (gc_type == FG_GC) {
1347 		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1348 						sbi->skipped_gc_rwsem)
1349 			skipped_round++;
1350 		last_skipped = sbi->skipped_atomic_files[FG_GC];
1351 		round++;
1352 	}
1353 
1354 	if (gc_type == FG_GC && seg_freed)
1355 		sbi->cur_victim_sec = NULL_SEGNO;
1356 
1357 	if (sync)
1358 		goto stop;
1359 
1360 	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1361 		if (skipped_round <= MAX_SKIP_GC_COUNT ||
1362 					skipped_round * 2 < round) {
1363 			segno = NULL_SEGNO;
1364 			goto gc_more;
1365 		}
1366 
1367 		if (first_skipped < last_skipped &&
1368 				(last_skipped - first_skipped) >
1369 						sbi->skipped_gc_rwsem) {
1370 			f2fs_drop_inmem_pages_all(sbi, true);
1371 			segno = NULL_SEGNO;
1372 			goto gc_more;
1373 		}
1374 		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1375 			ret = f2fs_write_checkpoint(sbi, &cpc);
1376 	}
1377 stop:
1378 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1379 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1380 
1381 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1382 				get_pages(sbi, F2FS_DIRTY_NODES),
1383 				get_pages(sbi, F2FS_DIRTY_DENTS),
1384 				get_pages(sbi, F2FS_DIRTY_IMETA),
1385 				free_sections(sbi),
1386 				free_segments(sbi),
1387 				reserved_segments(sbi),
1388 				prefree_segments(sbi));
1389 
1390 	up_write(&sbi->gc_lock);
1391 
1392 	put_gc_inode(&gc_list);
1393 
1394 	if (sync && !ret)
1395 		ret = sec_freed ? 0 : -EAGAIN;
1396 	return ret;
1397 }
1398 
1399 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1400 {
1401 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1402 
1403 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1404 
1405 	/* give warm/cold data area from slower device */
1406 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1407 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1408 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1409 }
1410 
1411 static int free_segment_range(struct f2fs_sb_info *sbi,
1412 				unsigned int secs, bool gc_only)
1413 {
1414 	unsigned int segno, next_inuse, start, end;
1415 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1416 	int gc_mode, gc_type;
1417 	int err = 0;
1418 	int type;
1419 
1420 	/* Force block allocation for GC */
1421 	MAIN_SECS(sbi) -= secs;
1422 	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
1423 	end = MAIN_SEGS(sbi) - 1;
1424 
1425 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1426 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1427 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
1428 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1429 
1430 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1431 		if (sbi->next_victim_seg[gc_type] >= start)
1432 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1433 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1434 
1435 	/* Move out cursegs from the target range */
1436 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++)
1437 		allocate_segment_for_resize(sbi, type, start, end);
1438 
1439 	/* do GC to move out valid blocks in the range */
1440 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1441 		struct gc_inode_list gc_list = {
1442 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1443 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1444 		};
1445 
1446 		do_garbage_collect(sbi, segno, &gc_list, FG_GC);
1447 		put_gc_inode(&gc_list);
1448 
1449 		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
1450 			err = -EAGAIN;
1451 			goto out;
1452 		}
1453 		if (fatal_signal_pending(current)) {
1454 			err = -ERESTARTSYS;
1455 			goto out;
1456 		}
1457 	}
1458 	if (gc_only)
1459 		goto out;
1460 
1461 	err = f2fs_write_checkpoint(sbi, &cpc);
1462 	if (err)
1463 		goto out;
1464 
1465 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1466 	if (next_inuse <= end) {
1467 		f2fs_err(sbi, "segno %u should be free but still inuse!",
1468 			 next_inuse);
1469 		f2fs_bug_on(sbi, 1);
1470 	}
1471 out:
1472 	MAIN_SECS(sbi) += secs;
1473 	return err;
1474 }
1475 
1476 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1477 {
1478 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1479 	int section_count;
1480 	int segment_count;
1481 	int segment_count_main;
1482 	long long block_count;
1483 	int segs = secs * sbi->segs_per_sec;
1484 
1485 	down_write(&sbi->sb_lock);
1486 
1487 	section_count = le32_to_cpu(raw_sb->section_count);
1488 	segment_count = le32_to_cpu(raw_sb->segment_count);
1489 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1490 	block_count = le64_to_cpu(raw_sb->block_count);
1491 
1492 	raw_sb->section_count = cpu_to_le32(section_count + secs);
1493 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1494 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1495 	raw_sb->block_count = cpu_to_le64(block_count +
1496 					(long long)segs * sbi->blocks_per_seg);
1497 	if (f2fs_is_multi_device(sbi)) {
1498 		int last_dev = sbi->s_ndevs - 1;
1499 		int dev_segs =
1500 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
1501 
1502 		raw_sb->devs[last_dev].total_segments =
1503 						cpu_to_le32(dev_segs + segs);
1504 	}
1505 
1506 	up_write(&sbi->sb_lock);
1507 }
1508 
1509 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1510 {
1511 	int segs = secs * sbi->segs_per_sec;
1512 	long long blks = (long long)segs * sbi->blocks_per_seg;
1513 	long long user_block_count =
1514 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1515 
1516 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1517 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1518 	MAIN_SECS(sbi) += secs;
1519 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1520 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1521 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
1522 
1523 	if (f2fs_is_multi_device(sbi)) {
1524 		int last_dev = sbi->s_ndevs - 1;
1525 
1526 		FDEV(last_dev).total_segments =
1527 				(int)FDEV(last_dev).total_segments + segs;
1528 		FDEV(last_dev).end_blk =
1529 				(long long)FDEV(last_dev).end_blk + blks;
1530 #ifdef CONFIG_BLK_DEV_ZONED
1531 		FDEV(last_dev).nr_blkz = (int)FDEV(last_dev).nr_blkz +
1532 					(int)(blks >> sbi->log_blocks_per_blkz);
1533 #endif
1534 	}
1535 }
1536 
1537 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1538 {
1539 	__u64 old_block_count, shrunk_blocks;
1540 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1541 	unsigned int secs;
1542 	int err = 0;
1543 	__u32 rem;
1544 
1545 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
1546 	if (block_count > old_block_count)
1547 		return -EINVAL;
1548 
1549 	if (f2fs_is_multi_device(sbi)) {
1550 		int last_dev = sbi->s_ndevs - 1;
1551 		__u64 last_segs = FDEV(last_dev).total_segments;
1552 
1553 		if (block_count + last_segs * sbi->blocks_per_seg <=
1554 								old_block_count)
1555 			return -EINVAL;
1556 	}
1557 
1558 	/* new fs size should align to section size */
1559 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
1560 	if (rem)
1561 		return -EINVAL;
1562 
1563 	if (block_count == old_block_count)
1564 		return 0;
1565 
1566 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
1567 		f2fs_err(sbi, "Should run fsck to repair first.");
1568 		return -EFSCORRUPTED;
1569 	}
1570 
1571 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
1572 		f2fs_err(sbi, "Checkpoint should be enabled.");
1573 		return -EINVAL;
1574 	}
1575 
1576 	shrunk_blocks = old_block_count - block_count;
1577 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
1578 
1579 	/* stop other GC */
1580 	if (!down_write_trylock(&sbi->gc_lock))
1581 		return -EAGAIN;
1582 
1583 	/* stop CP to protect MAIN_SEC in free_segment_range */
1584 	f2fs_lock_op(sbi);
1585 	err = free_segment_range(sbi, secs, true);
1586 	f2fs_unlock_op(sbi);
1587 	up_write(&sbi->gc_lock);
1588 	if (err)
1589 		return err;
1590 
1591 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
1592 
1593 	freeze_super(sbi->sb);
1594 	down_write(&sbi->gc_lock);
1595 	mutex_lock(&sbi->cp_mutex);
1596 
1597 	spin_lock(&sbi->stat_lock);
1598 	if (shrunk_blocks + valid_user_blocks(sbi) +
1599 		sbi->current_reserved_blocks + sbi->unusable_block_count +
1600 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
1601 		err = -ENOSPC;
1602 	else
1603 		sbi->user_block_count -= shrunk_blocks;
1604 	spin_unlock(&sbi->stat_lock);
1605 	if (err)
1606 		goto out_err;
1607 
1608 	err = free_segment_range(sbi, secs, false);
1609 	if (err)
1610 		goto recover_out;
1611 
1612 	update_sb_metadata(sbi, -secs);
1613 
1614 	err = f2fs_commit_super(sbi, false);
1615 	if (err) {
1616 		update_sb_metadata(sbi, secs);
1617 		goto recover_out;
1618 	}
1619 
1620 	update_fs_metadata(sbi, -secs);
1621 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1622 	set_sbi_flag(sbi, SBI_IS_DIRTY);
1623 
1624 	err = f2fs_write_checkpoint(sbi, &cpc);
1625 	if (err) {
1626 		update_fs_metadata(sbi, secs);
1627 		update_sb_metadata(sbi, secs);
1628 		f2fs_commit_super(sbi, false);
1629 	}
1630 recover_out:
1631 	if (err) {
1632 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1633 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
1634 
1635 		spin_lock(&sbi->stat_lock);
1636 		sbi->user_block_count += shrunk_blocks;
1637 		spin_unlock(&sbi->stat_lock);
1638 	}
1639 out_err:
1640 	mutex_unlock(&sbi->cp_mutex);
1641 	up_write(&sbi->gc_lock);
1642 	thaw_super(sbi->sb);
1643 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1644 	return err;
1645 }
1646