xref: /openbmc/linux/fs/f2fs/gc.c (revision 297e77e5)
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 unsigned int count_bits(const unsigned long *addr,
25 				unsigned int offset, unsigned int len);
26 
27 static int gc_thread_func(void *data)
28 {
29 	struct f2fs_sb_info *sbi = data;
30 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
31 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
32 	unsigned int wait_ms;
33 
34 	wait_ms = gc_th->min_sleep_time;
35 
36 	set_freezable();
37 	do {
38 		bool sync_mode;
39 
40 		wait_event_interruptible_timeout(*wq,
41 				kthread_should_stop() || freezing(current) ||
42 				gc_th->gc_wake,
43 				msecs_to_jiffies(wait_ms));
44 
45 		/* give it a try one time */
46 		if (gc_th->gc_wake)
47 			gc_th->gc_wake = 0;
48 
49 		if (try_to_freeze()) {
50 			stat_other_skip_bggc_count(sbi);
51 			continue;
52 		}
53 		if (kthread_should_stop())
54 			break;
55 
56 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
57 			increase_sleep_time(gc_th, &wait_ms);
58 			stat_other_skip_bggc_count(sbi);
59 			continue;
60 		}
61 
62 		if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
63 			f2fs_show_injection_info(sbi, FAULT_CHECKPOINT);
64 			f2fs_stop_checkpoint(sbi, false);
65 		}
66 
67 		if (!sb_start_write_trylock(sbi->sb)) {
68 			stat_other_skip_bggc_count(sbi);
69 			continue;
70 		}
71 
72 		/*
73 		 * [GC triggering condition]
74 		 * 0. GC is not conducted currently.
75 		 * 1. There are enough dirty segments.
76 		 * 2. IO subsystem is idle by checking the # of writeback pages.
77 		 * 3. IO subsystem is idle by checking the # of requests in
78 		 *    bdev's request list.
79 		 *
80 		 * Note) We have to avoid triggering GCs frequently.
81 		 * Because it is possible that some segments can be
82 		 * invalidated soon after by user update or deletion.
83 		 * So, I'd like to wait some time to collect dirty segments.
84 		 */
85 		if (sbi->gc_mode == GC_URGENT_HIGH) {
86 			wait_ms = gc_th->urgent_sleep_time;
87 			down_write(&sbi->gc_lock);
88 			goto do_gc;
89 		}
90 
91 		if (!down_write_trylock(&sbi->gc_lock)) {
92 			stat_other_skip_bggc_count(sbi);
93 			goto next;
94 		}
95 
96 		if (!is_idle(sbi, GC_TIME)) {
97 			increase_sleep_time(gc_th, &wait_ms);
98 			up_write(&sbi->gc_lock);
99 			stat_io_skip_bggc_count(sbi);
100 			goto next;
101 		}
102 
103 		if (has_enough_invalid_blocks(sbi))
104 			decrease_sleep_time(gc_th, &wait_ms);
105 		else
106 			increase_sleep_time(gc_th, &wait_ms);
107 do_gc:
108 		stat_inc_bggc_count(sbi->stat_info);
109 
110 		sync_mode = F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC;
111 
112 		/* if return value is not zero, no victim was selected */
113 		if (f2fs_gc(sbi, sync_mode, true, NULL_SEGNO))
114 			wait_ms = gc_th->no_gc_sleep_time;
115 
116 		trace_f2fs_background_gc(sbi->sb, wait_ms,
117 				prefree_segments(sbi), free_segments(sbi));
118 
119 		/* balancing f2fs's metadata periodically */
120 		f2fs_balance_fs_bg(sbi, true);
121 next:
122 		sb_end_write(sbi->sb);
123 
124 	} while (!kthread_should_stop());
125 	return 0;
126 }
127 
128 int f2fs_start_gc_thread(struct f2fs_sb_info *sbi)
129 {
130 	struct f2fs_gc_kthread *gc_th;
131 	dev_t dev = sbi->sb->s_bdev->bd_dev;
132 	int err = 0;
133 
134 	gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
135 	if (!gc_th) {
136 		err = -ENOMEM;
137 		goto out;
138 	}
139 
140 	gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
141 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
142 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
143 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
144 
145 	gc_th->gc_wake= 0;
146 
147 	sbi->gc_thread = gc_th;
148 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
149 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
150 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
151 	if (IS_ERR(gc_th->f2fs_gc_task)) {
152 		err = PTR_ERR(gc_th->f2fs_gc_task);
153 		kvfree(gc_th);
154 		sbi->gc_thread = NULL;
155 	}
156 out:
157 	return err;
158 }
159 
160 void f2fs_stop_gc_thread(struct f2fs_sb_info *sbi)
161 {
162 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
163 	if (!gc_th)
164 		return;
165 	kthread_stop(gc_th->f2fs_gc_task);
166 	kvfree(gc_th);
167 	sbi->gc_thread = NULL;
168 }
169 
170 static int select_gc_type(struct f2fs_sb_info *sbi, int gc_type)
171 {
172 	int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
173 
174 	switch (sbi->gc_mode) {
175 	case GC_IDLE_CB:
176 		gc_mode = GC_CB;
177 		break;
178 	case GC_IDLE_GREEDY:
179 	case GC_URGENT_HIGH:
180 		gc_mode = GC_GREEDY;
181 		break;
182 	}
183 	return gc_mode;
184 }
185 
186 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
187 			int type, struct victim_sel_policy *p)
188 {
189 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
190 
191 	if (p->alloc_mode == SSR) {
192 		p->gc_mode = GC_GREEDY;
193 		p->dirty_bitmap = dirty_i->dirty_segmap[type];
194 		p->max_search = dirty_i->nr_dirty[type];
195 		p->ofs_unit = 1;
196 	} else {
197 		p->gc_mode = select_gc_type(sbi, gc_type);
198 		p->ofs_unit = sbi->segs_per_sec;
199 		if (__is_large_section(sbi)) {
200 			p->dirty_bitmap = dirty_i->dirty_secmap;
201 			p->max_search = count_bits(p->dirty_bitmap,
202 						0, MAIN_SECS(sbi));
203 		} else {
204 			p->dirty_bitmap = dirty_i->dirty_segmap[DIRTY];
205 			p->max_search = dirty_i->nr_dirty[DIRTY];
206 		}
207 	}
208 
209 	/*
210 	 * adjust candidates range, should select all dirty segments for
211 	 * foreground GC and urgent GC cases.
212 	 */
213 	if (gc_type != FG_GC &&
214 			(sbi->gc_mode != GC_URGENT_HIGH) &&
215 			p->max_search > sbi->max_victim_search)
216 		p->max_search = sbi->max_victim_search;
217 
218 	/* let's select beginning hot/small space first in no_heap mode*/
219 	if (test_opt(sbi, NOHEAP) &&
220 		(type == CURSEG_HOT_DATA || IS_NODESEG(type)))
221 		p->offset = 0;
222 	else
223 		p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
224 }
225 
226 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
227 				struct victim_sel_policy *p)
228 {
229 	/* SSR allocates in a segment unit */
230 	if (p->alloc_mode == SSR)
231 		return sbi->blocks_per_seg;
232 	if (p->gc_mode == GC_GREEDY)
233 		return 2 * sbi->blocks_per_seg * p->ofs_unit;
234 	else if (p->gc_mode == GC_CB)
235 		return UINT_MAX;
236 	else /* No other gc_mode */
237 		return 0;
238 }
239 
240 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
241 {
242 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
243 	unsigned int secno;
244 
245 	/*
246 	 * If the gc_type is FG_GC, we can select victim segments
247 	 * selected by background GC before.
248 	 * Those segments guarantee they have small valid blocks.
249 	 */
250 	for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
251 		if (sec_usage_check(sbi, secno))
252 			continue;
253 		clear_bit(secno, dirty_i->victim_secmap);
254 		return GET_SEG_FROM_SEC(sbi, secno);
255 	}
256 	return NULL_SEGNO;
257 }
258 
259 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
260 {
261 	struct sit_info *sit_i = SIT_I(sbi);
262 	unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
263 	unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
264 	unsigned long long mtime = 0;
265 	unsigned int vblocks;
266 	unsigned char age = 0;
267 	unsigned char u;
268 	unsigned int i;
269 
270 	for (i = 0; i < sbi->segs_per_sec; i++)
271 		mtime += get_seg_entry(sbi, start + i)->mtime;
272 	vblocks = get_valid_blocks(sbi, segno, true);
273 
274 	mtime = div_u64(mtime, sbi->segs_per_sec);
275 	vblocks = div_u64(vblocks, sbi->segs_per_sec);
276 
277 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
278 
279 	/* Handle if the system time has changed by the user */
280 	if (mtime < sit_i->min_mtime)
281 		sit_i->min_mtime = mtime;
282 	if (mtime > sit_i->max_mtime)
283 		sit_i->max_mtime = mtime;
284 	if (sit_i->max_mtime != sit_i->min_mtime)
285 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
286 				sit_i->max_mtime - sit_i->min_mtime);
287 
288 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
289 }
290 
291 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
292 			unsigned int segno, struct victim_sel_policy *p)
293 {
294 	if (p->alloc_mode == SSR)
295 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
296 
297 	/* alloc_mode == LFS */
298 	if (p->gc_mode == GC_GREEDY)
299 		return get_valid_blocks(sbi, segno, true);
300 	else
301 		return get_cb_cost(sbi, segno);
302 }
303 
304 static unsigned int count_bits(const unsigned long *addr,
305 				unsigned int offset, unsigned int len)
306 {
307 	unsigned int end = offset + len, sum = 0;
308 
309 	while (offset < end) {
310 		if (test_bit(offset++, addr))
311 			++sum;
312 	}
313 	return sum;
314 }
315 
316 /*
317  * This function is called from two paths.
318  * One is garbage collection and the other is SSR segment selection.
319  * When it is called during GC, it just gets a victim segment
320  * and it does not remove it from dirty seglist.
321  * When it is called from SSR segment selection, it finds a segment
322  * which has minimum valid blocks and removes it from dirty seglist.
323  */
324 static int get_victim_by_default(struct f2fs_sb_info *sbi,
325 		unsigned int *result, int gc_type, int type, char alloc_mode)
326 {
327 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
328 	struct sit_info *sm = SIT_I(sbi);
329 	struct victim_sel_policy p;
330 	unsigned int secno, last_victim;
331 	unsigned int last_segment;
332 	unsigned int nsearched = 0;
333 	int ret = 0;
334 
335 	mutex_lock(&dirty_i->seglist_lock);
336 	last_segment = MAIN_SECS(sbi) * sbi->segs_per_sec;
337 
338 	p.alloc_mode = alloc_mode;
339 	select_policy(sbi, gc_type, type, &p);
340 
341 	p.min_segno = NULL_SEGNO;
342 	p.min_cost = get_max_cost(sbi, &p);
343 
344 	if (*result != NULL_SEGNO) {
345 		if (!get_valid_blocks(sbi, *result, false)) {
346 			ret = -ENODATA;
347 			goto out;
348 		}
349 
350 		if (sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
351 			ret = -EBUSY;
352 		else
353 			p.min_segno = *result;
354 		goto out;
355 	}
356 
357 	ret = -ENODATA;
358 	if (p.max_search == 0)
359 		goto out;
360 
361 	if (__is_large_section(sbi) && p.alloc_mode == LFS) {
362 		if (sbi->next_victim_seg[BG_GC] != NULL_SEGNO) {
363 			p.min_segno = sbi->next_victim_seg[BG_GC];
364 			*result = p.min_segno;
365 			sbi->next_victim_seg[BG_GC] = NULL_SEGNO;
366 			goto got_result;
367 		}
368 		if (gc_type == FG_GC &&
369 				sbi->next_victim_seg[FG_GC] != NULL_SEGNO) {
370 			p.min_segno = sbi->next_victim_seg[FG_GC];
371 			*result = p.min_segno;
372 			sbi->next_victim_seg[FG_GC] = NULL_SEGNO;
373 			goto got_result;
374 		}
375 	}
376 
377 	last_victim = sm->last_victim[p.gc_mode];
378 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
379 		p.min_segno = check_bg_victims(sbi);
380 		if (p.min_segno != NULL_SEGNO)
381 			goto got_it;
382 	}
383 
384 	while (1) {
385 		unsigned long cost, *dirty_bitmap;
386 		unsigned int unit_no, segno;
387 
388 		dirty_bitmap = p.dirty_bitmap;
389 		unit_no = find_next_bit(dirty_bitmap,
390 				last_segment / p.ofs_unit,
391 				p.offset / p.ofs_unit);
392 		segno = unit_no * p.ofs_unit;
393 		if (segno >= last_segment) {
394 			if (sm->last_victim[p.gc_mode]) {
395 				last_segment =
396 					sm->last_victim[p.gc_mode];
397 				sm->last_victim[p.gc_mode] = 0;
398 				p.offset = 0;
399 				continue;
400 			}
401 			break;
402 		}
403 
404 		p.offset = segno + p.ofs_unit;
405 		nsearched++;
406 
407 #ifdef CONFIG_F2FS_CHECK_FS
408 		/*
409 		 * skip selecting the invalid segno (that is failed due to block
410 		 * validity check failure during GC) to avoid endless GC loop in
411 		 * such cases.
412 		 */
413 		if (test_bit(segno, sm->invalid_segmap))
414 			goto next;
415 #endif
416 
417 		secno = GET_SEC_FROM_SEG(sbi, segno);
418 
419 		if (sec_usage_check(sbi, secno))
420 			goto next;
421 		/* Don't touch checkpointed data */
422 		if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
423 					get_ckpt_valid_blocks(sbi, segno) &&
424 					p.alloc_mode != SSR))
425 			goto next;
426 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
427 			goto next;
428 
429 		cost = get_gc_cost(sbi, segno, &p);
430 
431 		if (p.min_cost > cost) {
432 			p.min_segno = segno;
433 			p.min_cost = cost;
434 		}
435 next:
436 		if (nsearched >= p.max_search) {
437 			if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
438 				sm->last_victim[p.gc_mode] =
439 					last_victim + p.ofs_unit;
440 			else
441 				sm->last_victim[p.gc_mode] = segno + p.ofs_unit;
442 			sm->last_victim[p.gc_mode] %=
443 				(MAIN_SECS(sbi) * sbi->segs_per_sec);
444 			break;
445 		}
446 	}
447 	if (p.min_segno != NULL_SEGNO) {
448 got_it:
449 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
450 got_result:
451 		if (p.alloc_mode == LFS) {
452 			secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
453 			if (gc_type == FG_GC)
454 				sbi->cur_victim_sec = secno;
455 			else
456 				set_bit(secno, dirty_i->victim_secmap);
457 		}
458 		ret = 0;
459 
460 	}
461 out:
462 	if (p.min_segno != NULL_SEGNO)
463 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
464 				sbi->cur_victim_sec,
465 				prefree_segments(sbi), free_segments(sbi));
466 	mutex_unlock(&dirty_i->seglist_lock);
467 
468 	return ret;
469 }
470 
471 static const struct victim_selection default_v_ops = {
472 	.get_victim = get_victim_by_default,
473 };
474 
475 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
476 {
477 	struct inode_entry *ie;
478 
479 	ie = radix_tree_lookup(&gc_list->iroot, ino);
480 	if (ie)
481 		return ie->inode;
482 	return NULL;
483 }
484 
485 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
486 {
487 	struct inode_entry *new_ie;
488 
489 	if (inode == find_gc_inode(gc_list, inode->i_ino)) {
490 		iput(inode);
491 		return;
492 	}
493 	new_ie = f2fs_kmem_cache_alloc(f2fs_inode_entry_slab, GFP_NOFS);
494 	new_ie->inode = inode;
495 
496 	f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
497 	list_add_tail(&new_ie->list, &gc_list->ilist);
498 }
499 
500 static void put_gc_inode(struct gc_inode_list *gc_list)
501 {
502 	struct inode_entry *ie, *next_ie;
503 	list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
504 		radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
505 		iput(ie->inode);
506 		list_del(&ie->list);
507 		kmem_cache_free(f2fs_inode_entry_slab, ie);
508 	}
509 }
510 
511 static int check_valid_map(struct f2fs_sb_info *sbi,
512 				unsigned int segno, int offset)
513 {
514 	struct sit_info *sit_i = SIT_I(sbi);
515 	struct seg_entry *sentry;
516 	int ret;
517 
518 	down_read(&sit_i->sentry_lock);
519 	sentry = get_seg_entry(sbi, segno);
520 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
521 	up_read(&sit_i->sentry_lock);
522 	return ret;
523 }
524 
525 /*
526  * This function compares node address got in summary with that in NAT.
527  * On validity, copy that node with cold status, otherwise (invalid node)
528  * ignore that.
529  */
530 static int gc_node_segment(struct f2fs_sb_info *sbi,
531 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
532 {
533 	struct f2fs_summary *entry;
534 	block_t start_addr;
535 	int off;
536 	int phase = 0;
537 	bool fggc = (gc_type == FG_GC);
538 	int submitted = 0;
539 
540 	start_addr = START_BLOCK(sbi, segno);
541 
542 next_step:
543 	entry = sum;
544 
545 	if (fggc && phase == 2)
546 		atomic_inc(&sbi->wb_sync_req[NODE]);
547 
548 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
549 		nid_t nid = le32_to_cpu(entry->nid);
550 		struct page *node_page;
551 		struct node_info ni;
552 		int err;
553 
554 		/* stop BG_GC if there is not enough free sections. */
555 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
556 			return submitted;
557 
558 		if (check_valid_map(sbi, segno, off) == 0)
559 			continue;
560 
561 		if (phase == 0) {
562 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
563 							META_NAT, true);
564 			continue;
565 		}
566 
567 		if (phase == 1) {
568 			f2fs_ra_node_page(sbi, nid);
569 			continue;
570 		}
571 
572 		/* phase == 2 */
573 		node_page = f2fs_get_node_page(sbi, nid);
574 		if (IS_ERR(node_page))
575 			continue;
576 
577 		/* block may become invalid during f2fs_get_node_page */
578 		if (check_valid_map(sbi, segno, off) == 0) {
579 			f2fs_put_page(node_page, 1);
580 			continue;
581 		}
582 
583 		if (f2fs_get_node_info(sbi, nid, &ni)) {
584 			f2fs_put_page(node_page, 1);
585 			continue;
586 		}
587 
588 		if (ni.blk_addr != start_addr + off) {
589 			f2fs_put_page(node_page, 1);
590 			continue;
591 		}
592 
593 		err = f2fs_move_node_page(node_page, gc_type);
594 		if (!err && gc_type == FG_GC)
595 			submitted++;
596 		stat_inc_node_blk_count(sbi, 1, gc_type);
597 	}
598 
599 	if (++phase < 3)
600 		goto next_step;
601 
602 	if (fggc)
603 		atomic_dec(&sbi->wb_sync_req[NODE]);
604 	return submitted;
605 }
606 
607 /*
608  * Calculate start block index indicating the given node offset.
609  * Be careful, caller should give this node offset only indicating direct node
610  * blocks. If any node offsets, which point the other types of node blocks such
611  * as indirect or double indirect node blocks, are given, it must be a caller's
612  * bug.
613  */
614 block_t f2fs_start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
615 {
616 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
617 	unsigned int bidx;
618 
619 	if (node_ofs == 0)
620 		return 0;
621 
622 	if (node_ofs <= 2) {
623 		bidx = node_ofs - 1;
624 	} else if (node_ofs <= indirect_blks) {
625 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
626 		bidx = node_ofs - 2 - dec;
627 	} else {
628 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
629 		bidx = node_ofs - 5 - dec;
630 	}
631 	return bidx * ADDRS_PER_BLOCK(inode) + ADDRS_PER_INODE(inode);
632 }
633 
634 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
635 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
636 {
637 	struct page *node_page;
638 	nid_t nid;
639 	unsigned int ofs_in_node;
640 	block_t source_blkaddr;
641 
642 	nid = le32_to_cpu(sum->nid);
643 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
644 
645 	node_page = f2fs_get_node_page(sbi, nid);
646 	if (IS_ERR(node_page))
647 		return false;
648 
649 	if (f2fs_get_node_info(sbi, nid, dni)) {
650 		f2fs_put_page(node_page, 1);
651 		return false;
652 	}
653 
654 	if (sum->version != dni->version) {
655 		f2fs_warn(sbi, "%s: valid data with mismatched node version.",
656 			  __func__);
657 		set_sbi_flag(sbi, SBI_NEED_FSCK);
658 	}
659 
660 	*nofs = ofs_of_node(node_page);
661 	source_blkaddr = data_blkaddr(NULL, node_page, ofs_in_node);
662 	f2fs_put_page(node_page, 1);
663 
664 	if (source_blkaddr != blkaddr) {
665 #ifdef CONFIG_F2FS_CHECK_FS
666 		unsigned int segno = GET_SEGNO(sbi, blkaddr);
667 		unsigned long offset = GET_BLKOFF_FROM_SEG0(sbi, blkaddr);
668 
669 		if (unlikely(check_valid_map(sbi, segno, offset))) {
670 			if (!test_and_set_bit(segno, SIT_I(sbi)->invalid_segmap)) {
671 				f2fs_err(sbi, "mismatched blkaddr %u (source_blkaddr %u) in seg %u\n",
672 						blkaddr, source_blkaddr, segno);
673 				f2fs_bug_on(sbi, 1);
674 			}
675 		}
676 #endif
677 		return false;
678 	}
679 	return true;
680 }
681 
682 static int ra_data_block(struct inode *inode, pgoff_t index)
683 {
684 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
685 	struct address_space *mapping = inode->i_mapping;
686 	struct dnode_of_data dn;
687 	struct page *page;
688 	struct extent_info ei = {0, 0, 0};
689 	struct f2fs_io_info fio = {
690 		.sbi = sbi,
691 		.ino = inode->i_ino,
692 		.type = DATA,
693 		.temp = COLD,
694 		.op = REQ_OP_READ,
695 		.op_flags = 0,
696 		.encrypted_page = NULL,
697 		.in_list = false,
698 		.retry = false,
699 	};
700 	int err;
701 
702 	page = f2fs_grab_cache_page(mapping, index, true);
703 	if (!page)
704 		return -ENOMEM;
705 
706 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
707 		dn.data_blkaddr = ei.blk + index - ei.fofs;
708 		if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
709 						DATA_GENERIC_ENHANCE_READ))) {
710 			err = -EFSCORRUPTED;
711 			goto put_page;
712 		}
713 		goto got_it;
714 	}
715 
716 	set_new_dnode(&dn, inode, NULL, NULL, 0);
717 	err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
718 	if (err)
719 		goto put_page;
720 	f2fs_put_dnode(&dn);
721 
722 	if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
723 		err = -ENOENT;
724 		goto put_page;
725 	}
726 	if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
727 						DATA_GENERIC_ENHANCE))) {
728 		err = -EFSCORRUPTED;
729 		goto put_page;
730 	}
731 got_it:
732 	/* read page */
733 	fio.page = page;
734 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
735 
736 	/*
737 	 * don't cache encrypted data into meta inode until previous dirty
738 	 * data were writebacked to avoid racing between GC and flush.
739 	 */
740 	f2fs_wait_on_page_writeback(page, DATA, true, true);
741 
742 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
743 
744 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(sbi),
745 					dn.data_blkaddr,
746 					FGP_LOCK | FGP_CREAT, GFP_NOFS);
747 	if (!fio.encrypted_page) {
748 		err = -ENOMEM;
749 		goto put_page;
750 	}
751 
752 	err = f2fs_submit_page_bio(&fio);
753 	if (err)
754 		goto put_encrypted_page;
755 	f2fs_put_page(fio.encrypted_page, 0);
756 	f2fs_put_page(page, 1);
757 
758 	f2fs_update_iostat(sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
759 	f2fs_update_iostat(sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
760 
761 	return 0;
762 put_encrypted_page:
763 	f2fs_put_page(fio.encrypted_page, 1);
764 put_page:
765 	f2fs_put_page(page, 1);
766 	return err;
767 }
768 
769 /*
770  * Move data block via META_MAPPING while keeping locked data page.
771  * This can be used to move blocks, aka LBAs, directly on disk.
772  */
773 static int move_data_block(struct inode *inode, block_t bidx,
774 				int gc_type, unsigned int segno, int off)
775 {
776 	struct f2fs_io_info fio = {
777 		.sbi = F2FS_I_SB(inode),
778 		.ino = inode->i_ino,
779 		.type = DATA,
780 		.temp = COLD,
781 		.op = REQ_OP_READ,
782 		.op_flags = 0,
783 		.encrypted_page = NULL,
784 		.in_list = false,
785 		.retry = false,
786 	};
787 	struct dnode_of_data dn;
788 	struct f2fs_summary sum;
789 	struct node_info ni;
790 	struct page *page, *mpage;
791 	block_t newaddr;
792 	int err = 0;
793 	bool lfs_mode = f2fs_lfs_mode(fio.sbi);
794 
795 	/* do not read out */
796 	page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
797 	if (!page)
798 		return -ENOMEM;
799 
800 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
801 		err = -ENOENT;
802 		goto out;
803 	}
804 
805 	if (f2fs_is_atomic_file(inode)) {
806 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
807 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
808 		err = -EAGAIN;
809 		goto out;
810 	}
811 
812 	if (f2fs_is_pinned_file(inode)) {
813 		f2fs_pin_file_control(inode, true);
814 		err = -EAGAIN;
815 		goto out;
816 	}
817 
818 	set_new_dnode(&dn, inode, NULL, NULL, 0);
819 	err = f2fs_get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
820 	if (err)
821 		goto out;
822 
823 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
824 		ClearPageUptodate(page);
825 		err = -ENOENT;
826 		goto put_out;
827 	}
828 
829 	/*
830 	 * don't cache encrypted data into meta inode until previous dirty
831 	 * data were writebacked to avoid racing between GC and flush.
832 	 */
833 	f2fs_wait_on_page_writeback(page, DATA, true, true);
834 
835 	f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
836 
837 	err = f2fs_get_node_info(fio.sbi, dn.nid, &ni);
838 	if (err)
839 		goto put_out;
840 
841 	set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
842 
843 	/* read page */
844 	fio.page = page;
845 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
846 
847 	if (lfs_mode)
848 		down_write(&fio.sbi->io_order_lock);
849 
850 	mpage = f2fs_grab_cache_page(META_MAPPING(fio.sbi),
851 					fio.old_blkaddr, false);
852 	if (!mpage) {
853 		err = -ENOMEM;
854 		goto up_out;
855 	}
856 
857 	fio.encrypted_page = mpage;
858 
859 	/* read source block in mpage */
860 	if (!PageUptodate(mpage)) {
861 		err = f2fs_submit_page_bio(&fio);
862 		if (err) {
863 			f2fs_put_page(mpage, 1);
864 			goto up_out;
865 		}
866 
867 		f2fs_update_iostat(fio.sbi, FS_DATA_READ_IO, F2FS_BLKSIZE);
868 		f2fs_update_iostat(fio.sbi, FS_GDATA_READ_IO, F2FS_BLKSIZE);
869 
870 		lock_page(mpage);
871 		if (unlikely(mpage->mapping != META_MAPPING(fio.sbi) ||
872 						!PageUptodate(mpage))) {
873 			err = -EIO;
874 			f2fs_put_page(mpage, 1);
875 			goto up_out;
876 		}
877 	}
878 
879 	f2fs_allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
880 					&sum, CURSEG_COLD_DATA, NULL);
881 
882 	fio.encrypted_page = f2fs_pagecache_get_page(META_MAPPING(fio.sbi),
883 				newaddr, FGP_LOCK | FGP_CREAT, GFP_NOFS);
884 	if (!fio.encrypted_page) {
885 		err = -ENOMEM;
886 		f2fs_put_page(mpage, 1);
887 		goto recover_block;
888 	}
889 
890 	/* write target block */
891 	f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true, true);
892 	memcpy(page_address(fio.encrypted_page),
893 				page_address(mpage), PAGE_SIZE);
894 	f2fs_put_page(mpage, 1);
895 	invalidate_mapping_pages(META_MAPPING(fio.sbi),
896 				fio.old_blkaddr, fio.old_blkaddr);
897 
898 	set_page_dirty(fio.encrypted_page);
899 	if (clear_page_dirty_for_io(fio.encrypted_page))
900 		dec_page_count(fio.sbi, F2FS_DIRTY_META);
901 
902 	set_page_writeback(fio.encrypted_page);
903 	ClearPageError(page);
904 
905 	/* allocate block address */
906 	f2fs_wait_on_page_writeback(dn.node_page, NODE, true, true);
907 
908 	fio.op = REQ_OP_WRITE;
909 	fio.op_flags = REQ_SYNC;
910 	fio.new_blkaddr = newaddr;
911 	f2fs_submit_page_write(&fio);
912 	if (fio.retry) {
913 		err = -EAGAIN;
914 		if (PageWriteback(fio.encrypted_page))
915 			end_page_writeback(fio.encrypted_page);
916 		goto put_page_out;
917 	}
918 
919 	f2fs_update_iostat(fio.sbi, FS_GC_DATA_IO, F2FS_BLKSIZE);
920 
921 	f2fs_update_data_blkaddr(&dn, newaddr);
922 	set_inode_flag(inode, FI_APPEND_WRITE);
923 	if (page->index == 0)
924 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
925 put_page_out:
926 	f2fs_put_page(fio.encrypted_page, 1);
927 recover_block:
928 	if (err)
929 		f2fs_do_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
930 								true, true);
931 up_out:
932 	if (lfs_mode)
933 		up_write(&fio.sbi->io_order_lock);
934 put_out:
935 	f2fs_put_dnode(&dn);
936 out:
937 	f2fs_put_page(page, 1);
938 	return err;
939 }
940 
941 static int move_data_page(struct inode *inode, block_t bidx, int gc_type,
942 							unsigned int segno, int off)
943 {
944 	struct page *page;
945 	int err = 0;
946 
947 	page = f2fs_get_lock_data_page(inode, bidx, true);
948 	if (IS_ERR(page))
949 		return PTR_ERR(page);
950 
951 	if (!check_valid_map(F2FS_I_SB(inode), segno, off)) {
952 		err = -ENOENT;
953 		goto out;
954 	}
955 
956 	if (f2fs_is_atomic_file(inode)) {
957 		F2FS_I(inode)->i_gc_failures[GC_FAILURE_ATOMIC]++;
958 		F2FS_I_SB(inode)->skipped_atomic_files[gc_type]++;
959 		err = -EAGAIN;
960 		goto out;
961 	}
962 	if (f2fs_is_pinned_file(inode)) {
963 		if (gc_type == FG_GC)
964 			f2fs_pin_file_control(inode, true);
965 		err = -EAGAIN;
966 		goto out;
967 	}
968 
969 	if (gc_type == BG_GC) {
970 		if (PageWriteback(page)) {
971 			err = -EAGAIN;
972 			goto out;
973 		}
974 		set_page_dirty(page);
975 		set_cold_data(page);
976 	} else {
977 		struct f2fs_io_info fio = {
978 			.sbi = F2FS_I_SB(inode),
979 			.ino = inode->i_ino,
980 			.type = DATA,
981 			.temp = COLD,
982 			.op = REQ_OP_WRITE,
983 			.op_flags = REQ_SYNC,
984 			.old_blkaddr = NULL_ADDR,
985 			.page = page,
986 			.encrypted_page = NULL,
987 			.need_lock = LOCK_REQ,
988 			.io_type = FS_GC_DATA_IO,
989 		};
990 		bool is_dirty = PageDirty(page);
991 
992 retry:
993 		f2fs_wait_on_page_writeback(page, DATA, true, true);
994 
995 		set_page_dirty(page);
996 		if (clear_page_dirty_for_io(page)) {
997 			inode_dec_dirty_pages(inode);
998 			f2fs_remove_dirty_inode(inode);
999 		}
1000 
1001 		set_cold_data(page);
1002 
1003 		err = f2fs_do_write_data_page(&fio);
1004 		if (err) {
1005 			clear_cold_data(page);
1006 			if (err == -ENOMEM) {
1007 				congestion_wait(BLK_RW_ASYNC,
1008 						DEFAULT_IO_TIMEOUT);
1009 				goto retry;
1010 			}
1011 			if (is_dirty)
1012 				set_page_dirty(page);
1013 		}
1014 	}
1015 out:
1016 	f2fs_put_page(page, 1);
1017 	return err;
1018 }
1019 
1020 /*
1021  * This function tries to get parent node of victim data block, and identifies
1022  * data block validity. If the block is valid, copy that with cold status and
1023  * modify parent node.
1024  * If the parent node is not valid or the data block address is different,
1025  * the victim data block is ignored.
1026  */
1027 static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
1028 		struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
1029 {
1030 	struct super_block *sb = sbi->sb;
1031 	struct f2fs_summary *entry;
1032 	block_t start_addr;
1033 	int off;
1034 	int phase = 0;
1035 	int submitted = 0;
1036 
1037 	start_addr = START_BLOCK(sbi, segno);
1038 
1039 next_step:
1040 	entry = sum;
1041 
1042 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
1043 		struct page *data_page;
1044 		struct inode *inode;
1045 		struct node_info dni; /* dnode info for the data */
1046 		unsigned int ofs_in_node, nofs;
1047 		block_t start_bidx;
1048 		nid_t nid = le32_to_cpu(entry->nid);
1049 
1050 		/*
1051 		 * stop BG_GC if there is not enough free sections.
1052 		 * Or, stop GC if the segment becomes fully valid caused by
1053 		 * race condition along with SSR block allocation.
1054 		 */
1055 		if ((gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) ||
1056 				get_valid_blocks(sbi, segno, true) ==
1057 							BLKS_PER_SEC(sbi))
1058 			return submitted;
1059 
1060 		if (check_valid_map(sbi, segno, off) == 0)
1061 			continue;
1062 
1063 		if (phase == 0) {
1064 			f2fs_ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
1065 							META_NAT, true);
1066 			continue;
1067 		}
1068 
1069 		if (phase == 1) {
1070 			f2fs_ra_node_page(sbi, nid);
1071 			continue;
1072 		}
1073 
1074 		/* Get an inode by ino with checking validity */
1075 		if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
1076 			continue;
1077 
1078 		if (phase == 2) {
1079 			f2fs_ra_node_page(sbi, dni.ino);
1080 			continue;
1081 		}
1082 
1083 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
1084 
1085 		if (phase == 3) {
1086 			inode = f2fs_iget(sb, dni.ino);
1087 			if (IS_ERR(inode) || is_bad_inode(inode)) {
1088 				set_sbi_flag(sbi, SBI_NEED_FSCK);
1089 				continue;
1090 			}
1091 
1092 			if (!down_write_trylock(
1093 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
1094 				iput(inode);
1095 				sbi->skipped_gc_rwsem++;
1096 				continue;
1097 			}
1098 
1099 			start_bidx = f2fs_start_bidx_of_node(nofs, inode) +
1100 								ofs_in_node;
1101 
1102 			if (f2fs_post_read_required(inode)) {
1103 				int err = ra_data_block(inode, start_bidx);
1104 
1105 				up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1106 				if (err) {
1107 					iput(inode);
1108 					continue;
1109 				}
1110 				add_gc_inode(gc_list, inode);
1111 				continue;
1112 			}
1113 
1114 			data_page = f2fs_get_read_data_page(inode,
1115 						start_bidx, REQ_RAHEAD, true);
1116 			up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]);
1117 			if (IS_ERR(data_page)) {
1118 				iput(inode);
1119 				continue;
1120 			}
1121 
1122 			f2fs_put_page(data_page, 0);
1123 			add_gc_inode(gc_list, inode);
1124 			continue;
1125 		}
1126 
1127 		/* phase 4 */
1128 		inode = find_gc_inode(gc_list, dni.ino);
1129 		if (inode) {
1130 			struct f2fs_inode_info *fi = F2FS_I(inode);
1131 			bool locked = false;
1132 			int err;
1133 
1134 			if (S_ISREG(inode->i_mode)) {
1135 				if (!down_write_trylock(&fi->i_gc_rwsem[READ]))
1136 					continue;
1137 				if (!down_write_trylock(
1138 						&fi->i_gc_rwsem[WRITE])) {
1139 					sbi->skipped_gc_rwsem++;
1140 					up_write(&fi->i_gc_rwsem[READ]);
1141 					continue;
1142 				}
1143 				locked = true;
1144 
1145 				/* wait for all inflight aio data */
1146 				inode_dio_wait(inode);
1147 			}
1148 
1149 			start_bidx = f2fs_start_bidx_of_node(nofs, inode)
1150 								+ ofs_in_node;
1151 			if (f2fs_post_read_required(inode))
1152 				err = move_data_block(inode, start_bidx,
1153 							gc_type, segno, off);
1154 			else
1155 				err = move_data_page(inode, start_bidx, gc_type,
1156 								segno, off);
1157 
1158 			if (!err && (gc_type == FG_GC ||
1159 					f2fs_post_read_required(inode)))
1160 				submitted++;
1161 
1162 			if (locked) {
1163 				up_write(&fi->i_gc_rwsem[WRITE]);
1164 				up_write(&fi->i_gc_rwsem[READ]);
1165 			}
1166 
1167 			stat_inc_data_blk_count(sbi, 1, gc_type);
1168 		}
1169 	}
1170 
1171 	if (++phase < 5)
1172 		goto next_step;
1173 
1174 	return submitted;
1175 }
1176 
1177 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
1178 			int gc_type)
1179 {
1180 	struct sit_info *sit_i = SIT_I(sbi);
1181 	int ret;
1182 
1183 	down_write(&sit_i->sentry_lock);
1184 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
1185 					      NO_CHECK_TYPE, LFS);
1186 	up_write(&sit_i->sentry_lock);
1187 	return ret;
1188 }
1189 
1190 static int do_garbage_collect(struct f2fs_sb_info *sbi,
1191 				unsigned int start_segno,
1192 				struct gc_inode_list *gc_list, int gc_type)
1193 {
1194 	struct page *sum_page;
1195 	struct f2fs_summary_block *sum;
1196 	struct blk_plug plug;
1197 	unsigned int segno = start_segno;
1198 	unsigned int end_segno = start_segno + sbi->segs_per_sec;
1199 	int seg_freed = 0, migrated = 0;
1200 	unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
1201 						SUM_TYPE_DATA : SUM_TYPE_NODE;
1202 	int submitted = 0;
1203 
1204 	if (__is_large_section(sbi))
1205 		end_segno = rounddown(end_segno, sbi->segs_per_sec);
1206 
1207 	/* readahead multi ssa blocks those have contiguous address */
1208 	if (__is_large_section(sbi))
1209 		f2fs_ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
1210 					end_segno - segno, META_SSA, true);
1211 
1212 	/* reference all summary page */
1213 	while (segno < end_segno) {
1214 		sum_page = f2fs_get_sum_page(sbi, segno++);
1215 		if (IS_ERR(sum_page)) {
1216 			int err = PTR_ERR(sum_page);
1217 
1218 			end_segno = segno - 1;
1219 			for (segno = start_segno; segno < end_segno; segno++) {
1220 				sum_page = find_get_page(META_MAPPING(sbi),
1221 						GET_SUM_BLOCK(sbi, segno));
1222 				f2fs_put_page(sum_page, 0);
1223 				f2fs_put_page(sum_page, 0);
1224 			}
1225 			return err;
1226 		}
1227 		unlock_page(sum_page);
1228 	}
1229 
1230 	blk_start_plug(&plug);
1231 
1232 	for (segno = start_segno; segno < end_segno; segno++) {
1233 
1234 		/* find segment summary of victim */
1235 		sum_page = find_get_page(META_MAPPING(sbi),
1236 					GET_SUM_BLOCK(sbi, segno));
1237 		f2fs_put_page(sum_page, 0);
1238 
1239 		if (get_valid_blocks(sbi, segno, false) == 0)
1240 			goto freed;
1241 		if (gc_type == BG_GC && __is_large_section(sbi) &&
1242 				migrated >= sbi->migration_granularity)
1243 			goto skip;
1244 		if (!PageUptodate(sum_page) || unlikely(f2fs_cp_error(sbi)))
1245 			goto skip;
1246 
1247 		sum = page_address(sum_page);
1248 		if (type != GET_SUM_TYPE((&sum->footer))) {
1249 			f2fs_err(sbi, "Inconsistent segment (%u) type [%d, %d] in SSA and SIT",
1250 				 segno, type, GET_SUM_TYPE((&sum->footer)));
1251 			set_sbi_flag(sbi, SBI_NEED_FSCK);
1252 			f2fs_stop_checkpoint(sbi, false);
1253 			goto skip;
1254 		}
1255 
1256 		/*
1257 		 * this is to avoid deadlock:
1258 		 * - lock_page(sum_page)         - f2fs_replace_block
1259 		 *  - check_valid_map()            - down_write(sentry_lock)
1260 		 *   - down_read(sentry_lock)     - change_curseg()
1261 		 *                                  - lock_page(sum_page)
1262 		 */
1263 		if (type == SUM_TYPE_NODE)
1264 			submitted += gc_node_segment(sbi, sum->entries, segno,
1265 								gc_type);
1266 		else
1267 			submitted += gc_data_segment(sbi, sum->entries, gc_list,
1268 							segno, gc_type);
1269 
1270 		stat_inc_seg_count(sbi, type, gc_type);
1271 		migrated++;
1272 
1273 freed:
1274 		if (gc_type == FG_GC &&
1275 				get_valid_blocks(sbi, segno, false) == 0)
1276 			seg_freed++;
1277 
1278 		if (__is_large_section(sbi) && segno + 1 < end_segno)
1279 			sbi->next_victim_seg[gc_type] = segno + 1;
1280 skip:
1281 		f2fs_put_page(sum_page, 0);
1282 	}
1283 
1284 	if (submitted)
1285 		f2fs_submit_merged_write(sbi,
1286 				(type == SUM_TYPE_NODE) ? NODE : DATA);
1287 
1288 	blk_finish_plug(&plug);
1289 
1290 	stat_inc_call_count(sbi->stat_info);
1291 
1292 	return seg_freed;
1293 }
1294 
1295 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
1296 			bool background, unsigned int segno)
1297 {
1298 	int gc_type = sync ? FG_GC : BG_GC;
1299 	int sec_freed = 0, seg_freed = 0, total_freed = 0;
1300 	int ret = 0;
1301 	struct cp_control cpc;
1302 	unsigned int init_segno = segno;
1303 	struct gc_inode_list gc_list = {
1304 		.ilist = LIST_HEAD_INIT(gc_list.ilist),
1305 		.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1306 	};
1307 	unsigned long long last_skipped = sbi->skipped_atomic_files[FG_GC];
1308 	unsigned long long first_skipped;
1309 	unsigned int skipped_round = 0, round = 0;
1310 
1311 	trace_f2fs_gc_begin(sbi->sb, sync, background,
1312 				get_pages(sbi, F2FS_DIRTY_NODES),
1313 				get_pages(sbi, F2FS_DIRTY_DENTS),
1314 				get_pages(sbi, F2FS_DIRTY_IMETA),
1315 				free_sections(sbi),
1316 				free_segments(sbi),
1317 				reserved_segments(sbi),
1318 				prefree_segments(sbi));
1319 
1320 	cpc.reason = __get_cp_reason(sbi);
1321 	sbi->skipped_gc_rwsem = 0;
1322 	first_skipped = last_skipped;
1323 gc_more:
1324 	if (unlikely(!(sbi->sb->s_flags & SB_ACTIVE))) {
1325 		ret = -EINVAL;
1326 		goto stop;
1327 	}
1328 	if (unlikely(f2fs_cp_error(sbi))) {
1329 		ret = -EIO;
1330 		goto stop;
1331 	}
1332 
1333 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
1334 		/*
1335 		 * For example, if there are many prefree_segments below given
1336 		 * threshold, we can make them free by checkpoint. Then, we
1337 		 * secure free segments which doesn't need fggc any more.
1338 		 */
1339 		if (prefree_segments(sbi) &&
1340 				!is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
1341 			ret = f2fs_write_checkpoint(sbi, &cpc);
1342 			if (ret)
1343 				goto stop;
1344 		}
1345 		if (has_not_enough_free_secs(sbi, 0, 0))
1346 			gc_type = FG_GC;
1347 	}
1348 
1349 	/* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1350 	if (gc_type == BG_GC && !background) {
1351 		ret = -EINVAL;
1352 		goto stop;
1353 	}
1354 	ret = __get_victim(sbi, &segno, gc_type);
1355 	if (ret)
1356 		goto stop;
1357 
1358 	seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
1359 	if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
1360 		sec_freed++;
1361 	total_freed += seg_freed;
1362 
1363 	if (gc_type == FG_GC) {
1364 		if (sbi->skipped_atomic_files[FG_GC] > last_skipped ||
1365 						sbi->skipped_gc_rwsem)
1366 			skipped_round++;
1367 		last_skipped = sbi->skipped_atomic_files[FG_GC];
1368 		round++;
1369 	}
1370 
1371 	if (gc_type == FG_GC && seg_freed)
1372 		sbi->cur_victim_sec = NULL_SEGNO;
1373 
1374 	if (sync)
1375 		goto stop;
1376 
1377 	if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1378 		if (skipped_round <= MAX_SKIP_GC_COUNT ||
1379 					skipped_round * 2 < round) {
1380 			segno = NULL_SEGNO;
1381 			goto gc_more;
1382 		}
1383 
1384 		if (first_skipped < last_skipped &&
1385 				(last_skipped - first_skipped) >
1386 						sbi->skipped_gc_rwsem) {
1387 			f2fs_drop_inmem_pages_all(sbi, true);
1388 			segno = NULL_SEGNO;
1389 			goto gc_more;
1390 		}
1391 		if (gc_type == FG_GC && !is_sbi_flag_set(sbi, SBI_CP_DISABLED))
1392 			ret = f2fs_write_checkpoint(sbi, &cpc);
1393 	}
1394 stop:
1395 	SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1396 	SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1397 
1398 	trace_f2fs_gc_end(sbi->sb, ret, total_freed, sec_freed,
1399 				get_pages(sbi, F2FS_DIRTY_NODES),
1400 				get_pages(sbi, F2FS_DIRTY_DENTS),
1401 				get_pages(sbi, F2FS_DIRTY_IMETA),
1402 				free_sections(sbi),
1403 				free_segments(sbi),
1404 				reserved_segments(sbi),
1405 				prefree_segments(sbi));
1406 
1407 	up_write(&sbi->gc_lock);
1408 
1409 	put_gc_inode(&gc_list);
1410 
1411 	if (sync && !ret)
1412 		ret = sec_freed ? 0 : -EAGAIN;
1413 	return ret;
1414 }
1415 
1416 void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
1417 {
1418 	DIRTY_I(sbi)->v_ops = &default_v_ops;
1419 
1420 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
1421 
1422 	/* give warm/cold data area from slower device */
1423 	if (f2fs_is_multi_device(sbi) && !__is_large_section(sbi))
1424 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1425 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1426 }
1427 
1428 static int free_segment_range(struct f2fs_sb_info *sbi,
1429 				unsigned int secs, bool gc_only)
1430 {
1431 	unsigned int segno, next_inuse, start, end;
1432 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1433 	int gc_mode, gc_type;
1434 	int err = 0;
1435 	int type;
1436 
1437 	/* Force block allocation for GC */
1438 	MAIN_SECS(sbi) -= secs;
1439 	start = MAIN_SECS(sbi) * sbi->segs_per_sec;
1440 	end = MAIN_SEGS(sbi) - 1;
1441 
1442 	mutex_lock(&DIRTY_I(sbi)->seglist_lock);
1443 	for (gc_mode = 0; gc_mode < MAX_GC_POLICY; gc_mode++)
1444 		if (SIT_I(sbi)->last_victim[gc_mode] >= start)
1445 			SIT_I(sbi)->last_victim[gc_mode] = 0;
1446 
1447 	for (gc_type = BG_GC; gc_type <= FG_GC; gc_type++)
1448 		if (sbi->next_victim_seg[gc_type] >= start)
1449 			sbi->next_victim_seg[gc_type] = NULL_SEGNO;
1450 	mutex_unlock(&DIRTY_I(sbi)->seglist_lock);
1451 
1452 	/* Move out cursegs from the target range */
1453 	for (type = CURSEG_HOT_DATA; type < NR_CURSEG_TYPE; type++)
1454 		f2fs_allocate_segment_for_resize(sbi, type, start, end);
1455 
1456 	/* do GC to move out valid blocks in the range */
1457 	for (segno = start; segno <= end; segno += sbi->segs_per_sec) {
1458 		struct gc_inode_list gc_list = {
1459 			.ilist = LIST_HEAD_INIT(gc_list.ilist),
1460 			.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
1461 		};
1462 
1463 		do_garbage_collect(sbi, segno, &gc_list, FG_GC);
1464 		put_gc_inode(&gc_list);
1465 
1466 		if (!gc_only && get_valid_blocks(sbi, segno, true)) {
1467 			err = -EAGAIN;
1468 			goto out;
1469 		}
1470 		if (fatal_signal_pending(current)) {
1471 			err = -ERESTARTSYS;
1472 			goto out;
1473 		}
1474 	}
1475 	if (gc_only)
1476 		goto out;
1477 
1478 	err = f2fs_write_checkpoint(sbi, &cpc);
1479 	if (err)
1480 		goto out;
1481 
1482 	next_inuse = find_next_inuse(FREE_I(sbi), end + 1, start);
1483 	if (next_inuse <= end) {
1484 		f2fs_err(sbi, "segno %u should be free but still inuse!",
1485 			 next_inuse);
1486 		f2fs_bug_on(sbi, 1);
1487 	}
1488 out:
1489 	MAIN_SECS(sbi) += secs;
1490 	return err;
1491 }
1492 
1493 static void update_sb_metadata(struct f2fs_sb_info *sbi, int secs)
1494 {
1495 	struct f2fs_super_block *raw_sb = F2FS_RAW_SUPER(sbi);
1496 	int section_count;
1497 	int segment_count;
1498 	int segment_count_main;
1499 	long long block_count;
1500 	int segs = secs * sbi->segs_per_sec;
1501 
1502 	down_write(&sbi->sb_lock);
1503 
1504 	section_count = le32_to_cpu(raw_sb->section_count);
1505 	segment_count = le32_to_cpu(raw_sb->segment_count);
1506 	segment_count_main = le32_to_cpu(raw_sb->segment_count_main);
1507 	block_count = le64_to_cpu(raw_sb->block_count);
1508 
1509 	raw_sb->section_count = cpu_to_le32(section_count + secs);
1510 	raw_sb->segment_count = cpu_to_le32(segment_count + segs);
1511 	raw_sb->segment_count_main = cpu_to_le32(segment_count_main + segs);
1512 	raw_sb->block_count = cpu_to_le64(block_count +
1513 					(long long)segs * sbi->blocks_per_seg);
1514 	if (f2fs_is_multi_device(sbi)) {
1515 		int last_dev = sbi->s_ndevs - 1;
1516 		int dev_segs =
1517 			le32_to_cpu(raw_sb->devs[last_dev].total_segments);
1518 
1519 		raw_sb->devs[last_dev].total_segments =
1520 						cpu_to_le32(dev_segs + segs);
1521 	}
1522 
1523 	up_write(&sbi->sb_lock);
1524 }
1525 
1526 static void update_fs_metadata(struct f2fs_sb_info *sbi, int secs)
1527 {
1528 	int segs = secs * sbi->segs_per_sec;
1529 	long long blks = (long long)segs * sbi->blocks_per_seg;
1530 	long long user_block_count =
1531 				le64_to_cpu(F2FS_CKPT(sbi)->user_block_count);
1532 
1533 	SM_I(sbi)->segment_count = (int)SM_I(sbi)->segment_count + segs;
1534 	MAIN_SEGS(sbi) = (int)MAIN_SEGS(sbi) + segs;
1535 	MAIN_SECS(sbi) += secs;
1536 	FREE_I(sbi)->free_sections = (int)FREE_I(sbi)->free_sections + secs;
1537 	FREE_I(sbi)->free_segments = (int)FREE_I(sbi)->free_segments + segs;
1538 	F2FS_CKPT(sbi)->user_block_count = cpu_to_le64(user_block_count + blks);
1539 
1540 	if (f2fs_is_multi_device(sbi)) {
1541 		int last_dev = sbi->s_ndevs - 1;
1542 
1543 		FDEV(last_dev).total_segments =
1544 				(int)FDEV(last_dev).total_segments + segs;
1545 		FDEV(last_dev).end_blk =
1546 				(long long)FDEV(last_dev).end_blk + blks;
1547 #ifdef CONFIG_BLK_DEV_ZONED
1548 		FDEV(last_dev).nr_blkz = (int)FDEV(last_dev).nr_blkz +
1549 					(int)(blks >> sbi->log_blocks_per_blkz);
1550 #endif
1551 	}
1552 }
1553 
1554 int f2fs_resize_fs(struct f2fs_sb_info *sbi, __u64 block_count)
1555 {
1556 	__u64 old_block_count, shrunk_blocks;
1557 	struct cp_control cpc = { CP_RESIZE, 0, 0, 0 };
1558 	unsigned int secs;
1559 	int err = 0;
1560 	__u32 rem;
1561 
1562 	old_block_count = le64_to_cpu(F2FS_RAW_SUPER(sbi)->block_count);
1563 	if (block_count > old_block_count)
1564 		return -EINVAL;
1565 
1566 	if (f2fs_is_multi_device(sbi)) {
1567 		int last_dev = sbi->s_ndevs - 1;
1568 		__u64 last_segs = FDEV(last_dev).total_segments;
1569 
1570 		if (block_count + last_segs * sbi->blocks_per_seg <=
1571 								old_block_count)
1572 			return -EINVAL;
1573 	}
1574 
1575 	/* new fs size should align to section size */
1576 	div_u64_rem(block_count, BLKS_PER_SEC(sbi), &rem);
1577 	if (rem)
1578 		return -EINVAL;
1579 
1580 	if (block_count == old_block_count)
1581 		return 0;
1582 
1583 	if (is_sbi_flag_set(sbi, SBI_NEED_FSCK)) {
1584 		f2fs_err(sbi, "Should run fsck to repair first.");
1585 		return -EFSCORRUPTED;
1586 	}
1587 
1588 	if (test_opt(sbi, DISABLE_CHECKPOINT)) {
1589 		f2fs_err(sbi, "Checkpoint should be enabled.");
1590 		return -EINVAL;
1591 	}
1592 
1593 	shrunk_blocks = old_block_count - block_count;
1594 	secs = div_u64(shrunk_blocks, BLKS_PER_SEC(sbi));
1595 
1596 	/* stop other GC */
1597 	if (!down_write_trylock(&sbi->gc_lock))
1598 		return -EAGAIN;
1599 
1600 	/* stop CP to protect MAIN_SEC in free_segment_range */
1601 	f2fs_lock_op(sbi);
1602 	err = free_segment_range(sbi, secs, true);
1603 	f2fs_unlock_op(sbi);
1604 	up_write(&sbi->gc_lock);
1605 	if (err)
1606 		return err;
1607 
1608 	set_sbi_flag(sbi, SBI_IS_RESIZEFS);
1609 
1610 	freeze_super(sbi->sb);
1611 	down_write(&sbi->gc_lock);
1612 	mutex_lock(&sbi->cp_mutex);
1613 
1614 	spin_lock(&sbi->stat_lock);
1615 	if (shrunk_blocks + valid_user_blocks(sbi) +
1616 		sbi->current_reserved_blocks + sbi->unusable_block_count +
1617 		F2FS_OPTION(sbi).root_reserved_blocks > sbi->user_block_count)
1618 		err = -ENOSPC;
1619 	else
1620 		sbi->user_block_count -= shrunk_blocks;
1621 	spin_unlock(&sbi->stat_lock);
1622 	if (err)
1623 		goto out_err;
1624 
1625 	err = free_segment_range(sbi, secs, false);
1626 	if (err)
1627 		goto recover_out;
1628 
1629 	update_sb_metadata(sbi, -secs);
1630 
1631 	err = f2fs_commit_super(sbi, false);
1632 	if (err) {
1633 		update_sb_metadata(sbi, secs);
1634 		goto recover_out;
1635 	}
1636 
1637 	update_fs_metadata(sbi, -secs);
1638 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1639 	set_sbi_flag(sbi, SBI_IS_DIRTY);
1640 
1641 	err = f2fs_write_checkpoint(sbi, &cpc);
1642 	if (err) {
1643 		update_fs_metadata(sbi, secs);
1644 		update_sb_metadata(sbi, secs);
1645 		f2fs_commit_super(sbi, false);
1646 	}
1647 recover_out:
1648 	if (err) {
1649 		set_sbi_flag(sbi, SBI_NEED_FSCK);
1650 		f2fs_err(sbi, "resize_fs failed, should run fsck to repair!");
1651 
1652 		spin_lock(&sbi->stat_lock);
1653 		sbi->user_block_count += shrunk_blocks;
1654 		spin_unlock(&sbi->stat_lock);
1655 	}
1656 out_err:
1657 	mutex_unlock(&sbi->cp_mutex);
1658 	up_write(&sbi->gc_lock);
1659 	thaw_super(sbi->sb);
1660 	clear_sbi_flag(sbi, SBI_IS_RESIZEFS);
1661 	return err;
1662 }
1663