xref: /openbmc/linux/fs/f2fs/gc.c (revision f7018c21)
1 /*
2  * fs/f2fs/gc.c
3  *
4  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5  *             http://www.samsung.com/
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 #include <linux/fs.h>
12 #include <linux/module.h>
13 #include <linux/backing-dev.h>
14 #include <linux/init.h>
15 #include <linux/f2fs_fs.h>
16 #include <linux/kthread.h>
17 #include <linux/delay.h>
18 #include <linux/freezer.h>
19 #include <linux/blkdev.h>
20 
21 #include "f2fs.h"
22 #include "node.h"
23 #include "segment.h"
24 #include "gc.h"
25 #include <trace/events/f2fs.h>
26 
27 static struct kmem_cache *winode_slab;
28 
29 static int gc_thread_func(void *data)
30 {
31 	struct f2fs_sb_info *sbi = data;
32 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
33 	wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
34 	long wait_ms;
35 
36 	wait_ms = gc_th->min_sleep_time;
37 
38 	do {
39 		if (try_to_freeze())
40 			continue;
41 		else
42 			wait_event_interruptible_timeout(*wq,
43 						kthread_should_stop(),
44 						msecs_to_jiffies(wait_ms));
45 		if (kthread_should_stop())
46 			break;
47 
48 		if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
49 			wait_ms = increase_sleep_time(gc_th, wait_ms);
50 			continue;
51 		}
52 
53 		/*
54 		 * [GC triggering condition]
55 		 * 0. GC is not conducted currently.
56 		 * 1. There are enough dirty segments.
57 		 * 2. IO subsystem is idle by checking the # of writeback pages.
58 		 * 3. IO subsystem is idle by checking the # of requests in
59 		 *    bdev's request list.
60 		 *
61 		 * Note) We have to avoid triggering GCs too much frequently.
62 		 * Because it is possible that some segments can be
63 		 * invalidated soon after by user update or deletion.
64 		 * So, I'd like to wait some time to collect dirty segments.
65 		 */
66 		if (!mutex_trylock(&sbi->gc_mutex))
67 			continue;
68 
69 		if (!is_idle(sbi)) {
70 			wait_ms = increase_sleep_time(gc_th, wait_ms);
71 			mutex_unlock(&sbi->gc_mutex);
72 			continue;
73 		}
74 
75 		if (has_enough_invalid_blocks(sbi))
76 			wait_ms = decrease_sleep_time(gc_th, wait_ms);
77 		else
78 			wait_ms = increase_sleep_time(gc_th, wait_ms);
79 
80 		stat_inc_bggc_count(sbi);
81 
82 		/* if return value is not zero, no victim was selected */
83 		if (f2fs_gc(sbi))
84 			wait_ms = gc_th->no_gc_sleep_time;
85 
86 		/* balancing f2fs's metadata periodically */
87 		f2fs_balance_fs_bg(sbi);
88 
89 	} while (!kthread_should_stop());
90 	return 0;
91 }
92 
93 int start_gc_thread(struct f2fs_sb_info *sbi)
94 {
95 	struct f2fs_gc_kthread *gc_th;
96 	dev_t dev = sbi->sb->s_bdev->bd_dev;
97 	int err = 0;
98 
99 	if (!test_opt(sbi, BG_GC))
100 		goto out;
101 	gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
102 	if (!gc_th) {
103 		err = -ENOMEM;
104 		goto out;
105 	}
106 
107 	gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
108 	gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
109 	gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
110 
111 	gc_th->gc_idle = 0;
112 
113 	sbi->gc_thread = gc_th;
114 	init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
115 	sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
116 			"f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
117 	if (IS_ERR(gc_th->f2fs_gc_task)) {
118 		err = PTR_ERR(gc_th->f2fs_gc_task);
119 		kfree(gc_th);
120 		sbi->gc_thread = NULL;
121 	}
122 out:
123 	return err;
124 }
125 
126 void stop_gc_thread(struct f2fs_sb_info *sbi)
127 {
128 	struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
129 	if (!gc_th)
130 		return;
131 	kthread_stop(gc_th->f2fs_gc_task);
132 	kfree(gc_th);
133 	sbi->gc_thread = NULL;
134 }
135 
136 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
137 {
138 	int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
139 
140 	if (gc_th && gc_th->gc_idle) {
141 		if (gc_th->gc_idle == 1)
142 			gc_mode = GC_CB;
143 		else if (gc_th->gc_idle == 2)
144 			gc_mode = GC_GREEDY;
145 	}
146 	return gc_mode;
147 }
148 
149 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
150 			int type, struct victim_sel_policy *p)
151 {
152 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
153 
154 	if (p->alloc_mode == SSR) {
155 		p->gc_mode = GC_GREEDY;
156 		p->dirty_segmap = dirty_i->dirty_segmap[type];
157 		p->max_search = dirty_i->nr_dirty[type];
158 		p->ofs_unit = 1;
159 	} else {
160 		p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
161 		p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
162 		p->max_search = dirty_i->nr_dirty[DIRTY];
163 		p->ofs_unit = sbi->segs_per_sec;
164 	}
165 
166 	if (p->max_search > sbi->max_victim_search)
167 		p->max_search = sbi->max_victim_search;
168 
169 	p->offset = sbi->last_victim[p->gc_mode];
170 }
171 
172 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
173 				struct victim_sel_policy *p)
174 {
175 	/* SSR allocates in a segment unit */
176 	if (p->alloc_mode == SSR)
177 		return 1 << sbi->log_blocks_per_seg;
178 	if (p->gc_mode == GC_GREEDY)
179 		return (1 << sbi->log_blocks_per_seg) * p->ofs_unit;
180 	else if (p->gc_mode == GC_CB)
181 		return UINT_MAX;
182 	else /* No other gc_mode */
183 		return 0;
184 }
185 
186 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
187 {
188 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
189 	unsigned int hint = 0;
190 	unsigned int secno;
191 
192 	/*
193 	 * If the gc_type is FG_GC, we can select victim segments
194 	 * selected by background GC before.
195 	 * Those segments guarantee they have small valid blocks.
196 	 */
197 next:
198 	secno = find_next_bit(dirty_i->victim_secmap, TOTAL_SECS(sbi), hint++);
199 	if (secno < TOTAL_SECS(sbi)) {
200 		if (sec_usage_check(sbi, secno))
201 			goto next;
202 		clear_bit(secno, dirty_i->victim_secmap);
203 		return secno * sbi->segs_per_sec;
204 	}
205 	return NULL_SEGNO;
206 }
207 
208 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
209 {
210 	struct sit_info *sit_i = SIT_I(sbi);
211 	unsigned int secno = GET_SECNO(sbi, segno);
212 	unsigned int start = secno * sbi->segs_per_sec;
213 	unsigned long long mtime = 0;
214 	unsigned int vblocks;
215 	unsigned char age = 0;
216 	unsigned char u;
217 	unsigned int i;
218 
219 	for (i = 0; i < sbi->segs_per_sec; i++)
220 		mtime += get_seg_entry(sbi, start + i)->mtime;
221 	vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
222 
223 	mtime = div_u64(mtime, sbi->segs_per_sec);
224 	vblocks = div_u64(vblocks, sbi->segs_per_sec);
225 
226 	u = (vblocks * 100) >> sbi->log_blocks_per_seg;
227 
228 	/* Handle if the system time is changed by user */
229 	if (mtime < sit_i->min_mtime)
230 		sit_i->min_mtime = mtime;
231 	if (mtime > sit_i->max_mtime)
232 		sit_i->max_mtime = mtime;
233 	if (sit_i->max_mtime != sit_i->min_mtime)
234 		age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
235 				sit_i->max_mtime - sit_i->min_mtime);
236 
237 	return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
238 }
239 
240 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
241 			unsigned int segno, struct victim_sel_policy *p)
242 {
243 	if (p->alloc_mode == SSR)
244 		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
245 
246 	/* alloc_mode == LFS */
247 	if (p->gc_mode == GC_GREEDY)
248 		return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
249 	else
250 		return get_cb_cost(sbi, segno);
251 }
252 
253 /*
254  * This function is called from two paths.
255  * One is garbage collection and the other is SSR segment selection.
256  * When it is called during GC, it just gets a victim segment
257  * and it does not remove it from dirty seglist.
258  * When it is called from SSR segment selection, it finds a segment
259  * which has minimum valid blocks and removes it from dirty seglist.
260  */
261 static int get_victim_by_default(struct f2fs_sb_info *sbi,
262 		unsigned int *result, int gc_type, int type, char alloc_mode)
263 {
264 	struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
265 	struct victim_sel_policy p;
266 	unsigned int secno, max_cost;
267 	int nsearched = 0;
268 
269 	p.alloc_mode = alloc_mode;
270 	select_policy(sbi, gc_type, type, &p);
271 
272 	p.min_segno = NULL_SEGNO;
273 	p.min_cost = max_cost = get_max_cost(sbi, &p);
274 
275 	mutex_lock(&dirty_i->seglist_lock);
276 
277 	if (p.alloc_mode == LFS && gc_type == FG_GC) {
278 		p.min_segno = check_bg_victims(sbi);
279 		if (p.min_segno != NULL_SEGNO)
280 			goto got_it;
281 	}
282 
283 	while (1) {
284 		unsigned long cost;
285 		unsigned int segno;
286 
287 		segno = find_next_bit(p.dirty_segmap,
288 						TOTAL_SEGS(sbi), p.offset);
289 		if (segno >= TOTAL_SEGS(sbi)) {
290 			if (sbi->last_victim[p.gc_mode]) {
291 				sbi->last_victim[p.gc_mode] = 0;
292 				p.offset = 0;
293 				continue;
294 			}
295 			break;
296 		}
297 
298 		p.offset = segno + p.ofs_unit;
299 		if (p.ofs_unit > 1)
300 			p.offset -= segno % p.ofs_unit;
301 
302 		secno = GET_SECNO(sbi, segno);
303 
304 		if (sec_usage_check(sbi, secno))
305 			continue;
306 		if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
307 			continue;
308 
309 		cost = get_gc_cost(sbi, segno, &p);
310 
311 		if (p.min_cost > cost) {
312 			p.min_segno = segno;
313 			p.min_cost = cost;
314 		} else if (unlikely(cost == max_cost)) {
315 			continue;
316 		}
317 
318 		if (nsearched++ >= p.max_search) {
319 			sbi->last_victim[p.gc_mode] = segno;
320 			break;
321 		}
322 	}
323 	if (p.min_segno != NULL_SEGNO) {
324 got_it:
325 		if (p.alloc_mode == LFS) {
326 			secno = GET_SECNO(sbi, p.min_segno);
327 			if (gc_type == FG_GC)
328 				sbi->cur_victim_sec = secno;
329 			else
330 				set_bit(secno, dirty_i->victim_secmap);
331 		}
332 		*result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
333 
334 		trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
335 				sbi->cur_victim_sec,
336 				prefree_segments(sbi), free_segments(sbi));
337 	}
338 	mutex_unlock(&dirty_i->seglist_lock);
339 
340 	return (p.min_segno == NULL_SEGNO) ? 0 : 1;
341 }
342 
343 static const struct victim_selection default_v_ops = {
344 	.get_victim = get_victim_by_default,
345 };
346 
347 static struct inode *find_gc_inode(nid_t ino, struct list_head *ilist)
348 {
349 	struct inode_entry *ie;
350 
351 	list_for_each_entry(ie, ilist, list)
352 		if (ie->inode->i_ino == ino)
353 			return ie->inode;
354 	return NULL;
355 }
356 
357 static void add_gc_inode(struct inode *inode, struct list_head *ilist)
358 {
359 	struct inode_entry *new_ie;
360 
361 	if (inode == find_gc_inode(inode->i_ino, ilist)) {
362 		iput(inode);
363 		return;
364 	}
365 
366 	new_ie = f2fs_kmem_cache_alloc(winode_slab, GFP_NOFS);
367 	new_ie->inode = inode;
368 	list_add_tail(&new_ie->list, ilist);
369 }
370 
371 static void put_gc_inode(struct list_head *ilist)
372 {
373 	struct inode_entry *ie, *next_ie;
374 	list_for_each_entry_safe(ie, next_ie, ilist, list) {
375 		iput(ie->inode);
376 		list_del(&ie->list);
377 		kmem_cache_free(winode_slab, ie);
378 	}
379 }
380 
381 static int check_valid_map(struct f2fs_sb_info *sbi,
382 				unsigned int segno, int offset)
383 {
384 	struct sit_info *sit_i = SIT_I(sbi);
385 	struct seg_entry *sentry;
386 	int ret;
387 
388 	mutex_lock(&sit_i->sentry_lock);
389 	sentry = get_seg_entry(sbi, segno);
390 	ret = f2fs_test_bit(offset, sentry->cur_valid_map);
391 	mutex_unlock(&sit_i->sentry_lock);
392 	return ret;
393 }
394 
395 /*
396  * This function compares node address got in summary with that in NAT.
397  * On validity, copy that node with cold status, otherwise (invalid node)
398  * ignore that.
399  */
400 static void gc_node_segment(struct f2fs_sb_info *sbi,
401 		struct f2fs_summary *sum, unsigned int segno, int gc_type)
402 {
403 	bool initial = true;
404 	struct f2fs_summary *entry;
405 	int off;
406 
407 next_step:
408 	entry = sum;
409 
410 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
411 		nid_t nid = le32_to_cpu(entry->nid);
412 		struct page *node_page;
413 
414 		/* stop BG_GC if there is not enough free sections. */
415 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
416 			return;
417 
418 		if (check_valid_map(sbi, segno, off) == 0)
419 			continue;
420 
421 		if (initial) {
422 			ra_node_page(sbi, nid);
423 			continue;
424 		}
425 		node_page = get_node_page(sbi, nid);
426 		if (IS_ERR(node_page))
427 			continue;
428 
429 		/* set page dirty and write it */
430 		if (gc_type == FG_GC) {
431 			f2fs_wait_on_page_writeback(node_page, NODE);
432 			set_page_dirty(node_page);
433 		} else {
434 			if (!PageWriteback(node_page))
435 				set_page_dirty(node_page);
436 		}
437 		f2fs_put_page(node_page, 1);
438 		stat_inc_node_blk_count(sbi, 1);
439 	}
440 
441 	if (initial) {
442 		initial = false;
443 		goto next_step;
444 	}
445 
446 	if (gc_type == FG_GC) {
447 		struct writeback_control wbc = {
448 			.sync_mode = WB_SYNC_ALL,
449 			.nr_to_write = LONG_MAX,
450 			.for_reclaim = 0,
451 		};
452 		sync_node_pages(sbi, 0, &wbc);
453 
454 		/*
455 		 * In the case of FG_GC, it'd be better to reclaim this victim
456 		 * completely.
457 		 */
458 		if (get_valid_blocks(sbi, segno, 1) != 0)
459 			goto next_step;
460 	}
461 }
462 
463 /*
464  * Calculate start block index indicating the given node offset.
465  * Be careful, caller should give this node offset only indicating direct node
466  * blocks. If any node offsets, which point the other types of node blocks such
467  * as indirect or double indirect node blocks, are given, it must be a caller's
468  * bug.
469  */
470 block_t start_bidx_of_node(unsigned int node_ofs, struct f2fs_inode_info *fi)
471 {
472 	unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
473 	unsigned int bidx;
474 
475 	if (node_ofs == 0)
476 		return 0;
477 
478 	if (node_ofs <= 2) {
479 		bidx = node_ofs - 1;
480 	} else if (node_ofs <= indirect_blks) {
481 		int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
482 		bidx = node_ofs - 2 - dec;
483 	} else {
484 		int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
485 		bidx = node_ofs - 5 - dec;
486 	}
487 	return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(fi);
488 }
489 
490 static int check_dnode(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
491 		struct node_info *dni, block_t blkaddr, unsigned int *nofs)
492 {
493 	struct page *node_page;
494 	nid_t nid;
495 	unsigned int ofs_in_node;
496 	block_t source_blkaddr;
497 
498 	nid = le32_to_cpu(sum->nid);
499 	ofs_in_node = le16_to_cpu(sum->ofs_in_node);
500 
501 	node_page = get_node_page(sbi, nid);
502 	if (IS_ERR(node_page))
503 		return 0;
504 
505 	get_node_info(sbi, nid, dni);
506 
507 	if (sum->version != dni->version) {
508 		f2fs_put_page(node_page, 1);
509 		return 0;
510 	}
511 
512 	*nofs = ofs_of_node(node_page);
513 	source_blkaddr = datablock_addr(node_page, ofs_in_node);
514 	f2fs_put_page(node_page, 1);
515 
516 	if (source_blkaddr != blkaddr)
517 		return 0;
518 	return 1;
519 }
520 
521 static void move_data_page(struct inode *inode, struct page *page, int gc_type)
522 {
523 	struct f2fs_io_info fio = {
524 		.type = DATA,
525 		.rw = WRITE_SYNC,
526 	};
527 
528 	if (gc_type == BG_GC) {
529 		if (PageWriteback(page))
530 			goto out;
531 		set_page_dirty(page);
532 		set_cold_data(page);
533 	} else {
534 		f2fs_wait_on_page_writeback(page, DATA);
535 
536 		if (clear_page_dirty_for_io(page))
537 			inode_dec_dirty_dents(inode);
538 		set_cold_data(page);
539 		do_write_data_page(page, &fio);
540 		clear_cold_data(page);
541 	}
542 out:
543 	f2fs_put_page(page, 1);
544 }
545 
546 /*
547  * This function tries to get parent node of victim data block, and identifies
548  * data block validity. If the block is valid, copy that with cold status and
549  * modify parent node.
550  * If the parent node is not valid or the data block address is different,
551  * the victim data block is ignored.
552  */
553 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
554 		struct list_head *ilist, unsigned int segno, int gc_type)
555 {
556 	struct super_block *sb = sbi->sb;
557 	struct f2fs_summary *entry;
558 	block_t start_addr;
559 	int off;
560 	int phase = 0;
561 
562 	start_addr = START_BLOCK(sbi, segno);
563 
564 next_step:
565 	entry = sum;
566 
567 	for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
568 		struct page *data_page;
569 		struct inode *inode;
570 		struct node_info dni; /* dnode info for the data */
571 		unsigned int ofs_in_node, nofs;
572 		block_t start_bidx;
573 
574 		/* stop BG_GC if there is not enough free sections. */
575 		if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
576 			return;
577 
578 		if (check_valid_map(sbi, segno, off) == 0)
579 			continue;
580 
581 		if (phase == 0) {
582 			ra_node_page(sbi, le32_to_cpu(entry->nid));
583 			continue;
584 		}
585 
586 		/* Get an inode by ino with checking validity */
587 		if (check_dnode(sbi, entry, &dni, start_addr + off, &nofs) == 0)
588 			continue;
589 
590 		if (phase == 1) {
591 			ra_node_page(sbi, dni.ino);
592 			continue;
593 		}
594 
595 		ofs_in_node = le16_to_cpu(entry->ofs_in_node);
596 
597 		if (phase == 2) {
598 			inode = f2fs_iget(sb, dni.ino);
599 			if (IS_ERR(inode))
600 				continue;
601 
602 			start_bidx = start_bidx_of_node(nofs, F2FS_I(inode));
603 
604 			data_page = find_data_page(inode,
605 					start_bidx + ofs_in_node, false);
606 			if (IS_ERR(data_page))
607 				goto next_iput;
608 
609 			f2fs_put_page(data_page, 0);
610 			add_gc_inode(inode, ilist);
611 		} else {
612 			inode = find_gc_inode(dni.ino, ilist);
613 			if (inode) {
614 				start_bidx = start_bidx_of_node(nofs,
615 								F2FS_I(inode));
616 				data_page = get_lock_data_page(inode,
617 						start_bidx + ofs_in_node);
618 				if (IS_ERR(data_page))
619 					continue;
620 				move_data_page(inode, data_page, gc_type);
621 				stat_inc_data_blk_count(sbi, 1);
622 			}
623 		}
624 		continue;
625 next_iput:
626 		iput(inode);
627 	}
628 
629 	if (++phase < 4)
630 		goto next_step;
631 
632 	if (gc_type == FG_GC) {
633 		f2fs_submit_merged_bio(sbi, DATA, WRITE);
634 
635 		/*
636 		 * In the case of FG_GC, it'd be better to reclaim this victim
637 		 * completely.
638 		 */
639 		if (get_valid_blocks(sbi, segno, 1) != 0) {
640 			phase = 2;
641 			goto next_step;
642 		}
643 	}
644 }
645 
646 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
647 						int gc_type, int type)
648 {
649 	struct sit_info *sit_i = SIT_I(sbi);
650 	int ret;
651 	mutex_lock(&sit_i->sentry_lock);
652 	ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type, type, LFS);
653 	mutex_unlock(&sit_i->sentry_lock);
654 	return ret;
655 }
656 
657 static void do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
658 				struct list_head *ilist, int gc_type)
659 {
660 	struct page *sum_page;
661 	struct f2fs_summary_block *sum;
662 	struct blk_plug plug;
663 
664 	/* read segment summary of victim */
665 	sum_page = get_sum_page(sbi, segno);
666 
667 	blk_start_plug(&plug);
668 
669 	sum = page_address(sum_page);
670 
671 	switch (GET_SUM_TYPE((&sum->footer))) {
672 	case SUM_TYPE_NODE:
673 		gc_node_segment(sbi, sum->entries, segno, gc_type);
674 		break;
675 	case SUM_TYPE_DATA:
676 		gc_data_segment(sbi, sum->entries, ilist, segno, gc_type);
677 		break;
678 	}
679 	blk_finish_plug(&plug);
680 
681 	stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)));
682 	stat_inc_call_count(sbi->stat_info);
683 
684 	f2fs_put_page(sum_page, 1);
685 }
686 
687 int f2fs_gc(struct f2fs_sb_info *sbi)
688 {
689 	struct list_head ilist;
690 	unsigned int segno, i;
691 	int gc_type = BG_GC;
692 	int nfree = 0;
693 	int ret = -1;
694 
695 	INIT_LIST_HEAD(&ilist);
696 gc_more:
697 	if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
698 		goto stop;
699 	if (unlikely(is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)))
700 		goto stop;
701 
702 	if (gc_type == BG_GC && has_not_enough_free_secs(sbi, nfree)) {
703 		gc_type = FG_GC;
704 		write_checkpoint(sbi, false);
705 	}
706 
707 	if (!__get_victim(sbi, &segno, gc_type, NO_CHECK_TYPE))
708 		goto stop;
709 	ret = 0;
710 
711 	/* readahead multi ssa blocks those have contiguous address */
712 	if (sbi->segs_per_sec > 1)
713 		ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), sbi->segs_per_sec,
714 								META_SSA);
715 
716 	for (i = 0; i < sbi->segs_per_sec; i++)
717 		do_garbage_collect(sbi, segno + i, &ilist, gc_type);
718 
719 	if (gc_type == FG_GC) {
720 		sbi->cur_victim_sec = NULL_SEGNO;
721 		nfree++;
722 		WARN_ON(get_valid_blocks(sbi, segno, sbi->segs_per_sec));
723 	}
724 
725 	if (has_not_enough_free_secs(sbi, nfree))
726 		goto gc_more;
727 
728 	if (gc_type == FG_GC)
729 		write_checkpoint(sbi, false);
730 stop:
731 	mutex_unlock(&sbi->gc_mutex);
732 
733 	put_gc_inode(&ilist);
734 	return ret;
735 }
736 
737 void build_gc_manager(struct f2fs_sb_info *sbi)
738 {
739 	DIRTY_I(sbi)->v_ops = &default_v_ops;
740 }
741 
742 int __init create_gc_caches(void)
743 {
744 	winode_slab = f2fs_kmem_cache_create("f2fs_gc_inodes",
745 			sizeof(struct inode_entry));
746 	if (!winode_slab)
747 		return -ENOMEM;
748 	return 0;
749 }
750 
751 void destroy_gc_caches(void)
752 {
753 	kmem_cache_destroy(winode_slab);
754 }
755