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Linux/fs/f2fs/gc.c

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  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 
 20 #include "f2fs.h"
 21 #include "node.h"
 22 #include "segment.h"
 23 #include "gc.h"
 24 #include <trace/events/f2fs.h>
 25 
 26 static int gc_thread_func(void *data)
 27 {
 28         struct f2fs_sb_info *sbi = data;
 29         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
 30         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
 31         long wait_ms;
 32 
 33         wait_ms = gc_th->min_sleep_time;
 34 
 35         set_freezable();
 36         do {
 37                 wait_event_interruptible_timeout(*wq,
 38                                 kthread_should_stop() || freezing(current),
 39                                 msecs_to_jiffies(wait_ms));
 40 
 41                 if (try_to_freeze())
 42                         continue;
 43                 if (kthread_should_stop())
 44                         break;
 45 
 46                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
 47                         increase_sleep_time(gc_th, &wait_ms);
 48                         continue;
 49                 }
 50 
 51 #ifdef CONFIG_F2FS_FAULT_INJECTION
 52                 if (time_to_inject(sbi, FAULT_CHECKPOINT)) {
 53                         f2fs_show_injection_info(FAULT_CHECKPOINT);
 54                         f2fs_stop_checkpoint(sbi, false);
 55                 }
 56 #endif
 57 
 58                 /*
 59                  * [GC triggering condition]
 60                  * 0. GC is not conducted currently.
 61                  * 1. There are enough dirty segments.
 62                  * 2. IO subsystem is idle by checking the # of writeback pages.
 63                  * 3. IO subsystem is idle by checking the # of requests in
 64                  *    bdev's request list.
 65                  *
 66                  * Note) We have to avoid triggering GCs frequently.
 67                  * Because it is possible that some segments can be
 68                  * invalidated soon after by user update or deletion.
 69                  * So, I'd like to wait some time to collect dirty segments.
 70                  */
 71                 if (!mutex_trylock(&sbi->gc_mutex))
 72                         continue;
 73 
 74                 if (!is_idle(sbi)) {
 75                         increase_sleep_time(gc_th, &wait_ms);
 76                         mutex_unlock(&sbi->gc_mutex);
 77                         continue;
 78                 }
 79 
 80                 if (has_enough_invalid_blocks(sbi))
 81                         decrease_sleep_time(gc_th, &wait_ms);
 82                 else
 83                         increase_sleep_time(gc_th, &wait_ms);
 84 
 85                 stat_inc_bggc_count(sbi);
 86 
 87                 /* if return value is not zero, no victim was selected */
 88                 if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC), true, NULL_SEGNO))
 89                         wait_ms = gc_th->no_gc_sleep_time;
 90 
 91                 trace_f2fs_background_gc(sbi->sb, wait_ms,
 92                                 prefree_segments(sbi), free_segments(sbi));
 93 
 94                 /* balancing f2fs's metadata periodically */
 95                 f2fs_balance_fs_bg(sbi);
 96 
 97         } while (!kthread_should_stop());
 98         return 0;
 99 }
100 
101 int start_gc_thread(struct f2fs_sb_info *sbi)
102 {
103         struct f2fs_gc_kthread *gc_th;
104         dev_t dev = sbi->sb->s_bdev->bd_dev;
105         int err = 0;
106 
107         gc_th = f2fs_kmalloc(sbi, sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
108         if (!gc_th) {
109                 err = -ENOMEM;
110                 goto out;
111         }
112 
113         gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
114         gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
115         gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
116 
117         gc_th->gc_idle = 0;
118 
119         sbi->gc_thread = gc_th;
120         init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
121         sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
122                         "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
123         if (IS_ERR(gc_th->f2fs_gc_task)) {
124                 err = PTR_ERR(gc_th->f2fs_gc_task);
125                 kfree(gc_th);
126                 sbi->gc_thread = NULL;
127         }
128 out:
129         return err;
130 }
131 
132 void stop_gc_thread(struct f2fs_sb_info *sbi)
133 {
134         struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
135         if (!gc_th)
136                 return;
137         kthread_stop(gc_th->f2fs_gc_task);
138         kfree(gc_th);
139         sbi->gc_thread = NULL;
140 }
141 
142 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
143 {
144         int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
145 
146         if (gc_th && gc_th->gc_idle) {
147                 if (gc_th->gc_idle == 1)
148                         gc_mode = GC_CB;
149                 else if (gc_th->gc_idle == 2)
150                         gc_mode = GC_GREEDY;
151         }
152         return gc_mode;
153 }
154 
155 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
156                         int type, struct victim_sel_policy *p)
157 {
158         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
159 
160         if (p->alloc_mode == SSR) {
161                 p->gc_mode = GC_GREEDY;
162                 p->dirty_segmap = dirty_i->dirty_segmap[type];
163                 p->max_search = dirty_i->nr_dirty[type];
164                 p->ofs_unit = 1;
165         } else {
166                 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
167                 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
168                 p->max_search = dirty_i->nr_dirty[DIRTY];
169                 p->ofs_unit = sbi->segs_per_sec;
170         }
171 
172         /* we need to check every dirty segments in the FG_GC case */
173         if (gc_type != FG_GC && p->max_search > sbi->max_victim_search)
174                 p->max_search = sbi->max_victim_search;
175 
176         /* let's select beginning hot/small space first */
177         if (type == CURSEG_HOT_DATA || IS_NODESEG(type))
178                 p->offset = 0;
179         else
180                 p->offset = SIT_I(sbi)->last_victim[p->gc_mode];
181 }
182 
183 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
184                                 struct victim_sel_policy *p)
185 {
186         /* SSR allocates in a segment unit */
187         if (p->alloc_mode == SSR)
188                 return sbi->blocks_per_seg;
189         if (p->gc_mode == GC_GREEDY)
190                 return 2 * sbi->blocks_per_seg * p->ofs_unit;
191         else if (p->gc_mode == GC_CB)
192                 return UINT_MAX;
193         else /* No other gc_mode */
194                 return 0;
195 }
196 
197 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
198 {
199         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
200         unsigned int secno;
201 
202         /*
203          * If the gc_type is FG_GC, we can select victim segments
204          * selected by background GC before.
205          * Those segments guarantee they have small valid blocks.
206          */
207         for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
208                 if (sec_usage_check(sbi, secno))
209                         continue;
210 
211                 if (no_fggc_candidate(sbi, secno))
212                         continue;
213 
214                 clear_bit(secno, dirty_i->victim_secmap);
215                 return GET_SEG_FROM_SEC(sbi, secno);
216         }
217         return NULL_SEGNO;
218 }
219 
220 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
221 {
222         struct sit_info *sit_i = SIT_I(sbi);
223         unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
224         unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
225         unsigned long long mtime = 0;
226         unsigned int vblocks;
227         unsigned char age = 0;
228         unsigned char u;
229         unsigned int i;
230 
231         for (i = 0; i < sbi->segs_per_sec; i++)
232                 mtime += get_seg_entry(sbi, start + i)->mtime;
233         vblocks = get_valid_blocks(sbi, segno, true);
234 
235         mtime = div_u64(mtime, sbi->segs_per_sec);
236         vblocks = div_u64(vblocks, sbi->segs_per_sec);
237 
238         u = (vblocks * 100) >> sbi->log_blocks_per_seg;
239 
240         /* Handle if the system time has changed by the user */
241         if (mtime < sit_i->min_mtime)
242                 sit_i->min_mtime = mtime;
243         if (mtime > sit_i->max_mtime)
244                 sit_i->max_mtime = mtime;
245         if (sit_i->max_mtime != sit_i->min_mtime)
246                 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
247                                 sit_i->max_mtime - sit_i->min_mtime);
248 
249         return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
250 }
251 
252 static unsigned int get_greedy_cost(struct f2fs_sb_info *sbi,
253                                                 unsigned int segno)
254 {
255         unsigned int valid_blocks =
256                         get_valid_blocks(sbi, segno, true);
257 
258         return IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
259                                 valid_blocks * 2 : valid_blocks;
260 }
261 
262 static unsigned int get_ssr_cost(struct f2fs_sb_info *sbi,
263                                                 unsigned int segno)
264 {
265         struct seg_entry *se = get_seg_entry(sbi, segno);
266 
267         return se->ckpt_valid_blocks > se->valid_blocks ?
268                                 se->ckpt_valid_blocks : se->valid_blocks;
269 }
270 
271 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
272                         unsigned int segno, struct victim_sel_policy *p)
273 {
274         if (p->alloc_mode == SSR)
275                 return get_ssr_cost(sbi, segno);
276 
277         /* alloc_mode == LFS */
278         if (p->gc_mode == GC_GREEDY)
279                 return get_greedy_cost(sbi, segno);
280         else
281                 return get_cb_cost(sbi, segno);
282 }
283 
284 static unsigned int count_bits(const unsigned long *addr,
285                                 unsigned int offset, unsigned int len)
286 {
287         unsigned int end = offset + len, sum = 0;
288 
289         while (offset < end) {
290                 if (test_bit(offset++, addr))
291                         ++sum;
292         }
293         return sum;
294 }
295 
296 /*
297  * This function is called from two paths.
298  * One is garbage collection and the other is SSR segment selection.
299  * When it is called during GC, it just gets a victim segment
300  * and it does not remove it from dirty seglist.
301  * When it is called from SSR segment selection, it finds a segment
302  * which has minimum valid blocks and removes it from dirty seglist.
303  */
304 static int get_victim_by_default(struct f2fs_sb_info *sbi,
305                 unsigned int *result, int gc_type, int type, char alloc_mode)
306 {
307         struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
308         struct sit_info *sm = SIT_I(sbi);
309         struct victim_sel_policy p;
310         unsigned int secno, last_victim;
311         unsigned int last_segment = MAIN_SEGS(sbi);
312         unsigned int nsearched = 0;
313 
314         mutex_lock(&dirty_i->seglist_lock);
315 
316         p.alloc_mode = alloc_mode;
317         select_policy(sbi, gc_type, type, &p);
318 
319         p.min_segno = NULL_SEGNO;
320         p.min_cost = get_max_cost(sbi, &p);
321 
322         if (*result != NULL_SEGNO) {
323                 if (IS_DATASEG(get_seg_entry(sbi, *result)->type) &&
324                         get_valid_blocks(sbi, *result, false) &&
325                         !sec_usage_check(sbi, GET_SEC_FROM_SEG(sbi, *result)))
326                         p.min_segno = *result;
327                 goto out;
328         }
329 
330         if (p.max_search == 0)
331                 goto out;
332 
333         last_victim = sm->last_victim[p.gc_mode];
334         if (p.alloc_mode == LFS && gc_type == FG_GC) {
335                 p.min_segno = check_bg_victims(sbi);
336                 if (p.min_segno != NULL_SEGNO)
337                         goto got_it;
338         }
339 
340         while (1) {
341                 unsigned long cost;
342                 unsigned int segno;
343 
344                 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
345                 if (segno >= last_segment) {
346                         if (sm->last_victim[p.gc_mode]) {
347                                 last_segment =
348                                         sm->last_victim[p.gc_mode];
349                                 sm->last_victim[p.gc_mode] = 0;
350                                 p.offset = 0;
351                                 continue;
352                         }
353                         break;
354                 }
355 
356                 p.offset = segno + p.ofs_unit;
357                 if (p.ofs_unit > 1) {
358                         p.offset -= segno % p.ofs_unit;
359                         nsearched += count_bits(p.dirty_segmap,
360                                                 p.offset - p.ofs_unit,
361                                                 p.ofs_unit);
362                 } else {
363                         nsearched++;
364                 }
365 
366                 secno = GET_SEC_FROM_SEG(sbi, segno);
367 
368                 if (sec_usage_check(sbi, secno))
369                         goto next;
370                 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
371                         goto next;
372                 if (gc_type == FG_GC && p.alloc_mode == LFS &&
373                                         no_fggc_candidate(sbi, secno))
374                         goto next;
375 
376                 cost = get_gc_cost(sbi, segno, &p);
377 
378                 if (p.min_cost > cost) {
379                         p.min_segno = segno;
380                         p.min_cost = cost;
381                 }
382 next:
383                 if (nsearched >= p.max_search) {
384                         if (!sm->last_victim[p.gc_mode] && segno <= last_victim)
385                                 sm->last_victim[p.gc_mode] = last_victim + 1;
386                         else
387                                 sm->last_victim[p.gc_mode] = segno + 1;
388                         sm->last_victim[p.gc_mode] %= MAIN_SEGS(sbi);
389                         break;
390                 }
391         }
392         if (p.min_segno != NULL_SEGNO) {
393 got_it:
394                 if (p.alloc_mode == LFS) {
395                         secno = GET_SEC_FROM_SEG(sbi, p.min_segno);
396                         if (gc_type == FG_GC)
397                                 sbi->cur_victim_sec = secno;
398                         else
399                                 set_bit(secno, dirty_i->victim_secmap);
400                 }
401                 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
402 
403                 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
404                                 sbi->cur_victim_sec,
405                                 prefree_segments(sbi), free_segments(sbi));
406         }
407 out:
408         mutex_unlock(&dirty_i->seglist_lock);
409 
410         return (p.min_segno == NULL_SEGNO) ? 0 : 1;
411 }
412 
413 static const struct victim_selection default_v_ops = {
414         .get_victim = get_victim_by_default,
415 };
416 
417 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
418 {
419         struct inode_entry *ie;
420 
421         ie = radix_tree_lookup(&gc_list->iroot, ino);
422         if (ie)
423                 return ie->inode;
424         return NULL;
425 }
426 
427 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
428 {
429         struct inode_entry *new_ie;
430 
431         if (inode == find_gc_inode(gc_list, inode->i_ino)) {
432                 iput(inode);
433                 return;
434         }
435         new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
436         new_ie->inode = inode;
437 
438         f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
439         list_add_tail(&new_ie->list, &gc_list->ilist);
440 }
441 
442 static void put_gc_inode(struct gc_inode_list *gc_list)
443 {
444         struct inode_entry *ie, *next_ie;
445         list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
446                 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
447                 iput(ie->inode);
448                 list_del(&ie->list);
449                 kmem_cache_free(inode_entry_slab, ie);
450         }
451 }
452 
453 static int check_valid_map(struct f2fs_sb_info *sbi,
454                                 unsigned int segno, int offset)
455 {
456         struct sit_info *sit_i = SIT_I(sbi);
457         struct seg_entry *sentry;
458         int ret;
459 
460         mutex_lock(&sit_i->sentry_lock);
461         sentry = get_seg_entry(sbi, segno);
462         ret = f2fs_test_bit(offset, sentry->cur_valid_map);
463         mutex_unlock(&sit_i->sentry_lock);
464         return ret;
465 }
466 
467 /*
468  * This function compares node address got in summary with that in NAT.
469  * On validity, copy that node with cold status, otherwise (invalid node)
470  * ignore that.
471  */
472 static void gc_node_segment(struct f2fs_sb_info *sbi,
473                 struct f2fs_summary *sum, unsigned int segno, int gc_type)
474 {
475         struct f2fs_summary *entry;
476         block_t start_addr;
477         int off;
478         int phase = 0;
479 
480         start_addr = START_BLOCK(sbi, segno);
481 
482 next_step:
483         entry = sum;
484 
485         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
486                 nid_t nid = le32_to_cpu(entry->nid);
487                 struct page *node_page;
488                 struct node_info ni;
489 
490                 /* stop BG_GC if there is not enough free sections. */
491                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
492                         return;
493 
494                 if (check_valid_map(sbi, segno, off) == 0)
495                         continue;
496 
497                 if (phase == 0) {
498                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
499                                                         META_NAT, true);
500                         continue;
501                 }
502 
503                 if (phase == 1) {
504                         ra_node_page(sbi, nid);
505                         continue;
506                 }
507 
508                 /* phase == 2 */
509                 node_page = get_node_page(sbi, nid);
510                 if (IS_ERR(node_page))
511                         continue;
512 
513                 /* block may become invalid during get_node_page */
514                 if (check_valid_map(sbi, segno, off) == 0) {
515                         f2fs_put_page(node_page, 1);
516                         continue;
517                 }
518 
519                 get_node_info(sbi, nid, &ni);
520                 if (ni.blk_addr != start_addr + off) {
521                         f2fs_put_page(node_page, 1);
522                         continue;
523                 }
524 
525                 move_node_page(node_page, gc_type);
526                 stat_inc_node_blk_count(sbi, 1, gc_type);
527         }
528 
529         if (++phase < 3)
530                 goto next_step;
531 }
532 
533 /*
534  * Calculate start block index indicating the given node offset.
535  * Be careful, caller should give this node offset only indicating direct node
536  * blocks. If any node offsets, which point the other types of node blocks such
537  * as indirect or double indirect node blocks, are given, it must be a caller's
538  * bug.
539  */
540 block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
541 {
542         unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
543         unsigned int bidx;
544 
545         if (node_ofs == 0)
546                 return 0;
547 
548         if (node_ofs <= 2) {
549                 bidx = node_ofs - 1;
550         } else if (node_ofs <= indirect_blks) {
551                 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
552                 bidx = node_ofs - 2 - dec;
553         } else {
554                 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
555                 bidx = node_ofs - 5 - dec;
556         }
557         return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
558 }
559 
560 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
561                 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
562 {
563         struct page *node_page;
564         nid_t nid;
565         unsigned int ofs_in_node;
566         block_t source_blkaddr;
567 
568         nid = le32_to_cpu(sum->nid);
569         ofs_in_node = le16_to_cpu(sum->ofs_in_node);
570 
571         node_page = get_node_page(sbi, nid);
572         if (IS_ERR(node_page))
573                 return false;
574 
575         get_node_info(sbi, nid, dni);
576 
577         if (sum->version != dni->version) {
578                 f2fs_msg(sbi->sb, KERN_WARNING,
579                                 "%s: valid data with mismatched node version.",
580                                 __func__);
581                 set_sbi_flag(sbi, SBI_NEED_FSCK);
582         }
583 
584         *nofs = ofs_of_node(node_page);
585         source_blkaddr = datablock_addr(node_page, ofs_in_node);
586         f2fs_put_page(node_page, 1);
587 
588         if (source_blkaddr != blkaddr)
589                 return false;
590         return true;
591 }
592 
593 static void move_encrypted_block(struct inode *inode, block_t bidx,
594                                                         unsigned int segno, int off)
595 {
596         struct f2fs_io_info fio = {
597                 .sbi = F2FS_I_SB(inode),
598                 .type = DATA,
599                 .temp = COLD,
600                 .op = REQ_OP_READ,
601                 .op_flags = 0,
602                 .encrypted_page = NULL,
603                 .in_list = false,
604         };
605         struct dnode_of_data dn;
606         struct f2fs_summary sum;
607         struct node_info ni;
608         struct page *page;
609         block_t newaddr;
610         int err;
611 
612         /* do not read out */
613         page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
614         if (!page)
615                 return;
616 
617         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
618                 goto out;
619 
620         if (f2fs_is_atomic_file(inode))
621                 goto out;
622 
623         set_new_dnode(&dn, inode, NULL, NULL, 0);
624         err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
625         if (err)
626                 goto out;
627 
628         if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
629                 ClearPageUptodate(page);
630                 goto put_out;
631         }
632 
633         /*
634          * don't cache encrypted data into meta inode until previous dirty
635          * data were writebacked to avoid racing between GC and flush.
636          */
637         f2fs_wait_on_page_writeback(page, DATA, true);
638 
639         get_node_info(fio.sbi, dn.nid, &ni);
640         set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
641 
642         /* read page */
643         fio.page = page;
644         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
645 
646         allocate_data_block(fio.sbi, NULL, fio.old_blkaddr, &newaddr,
647                                         &sum, CURSEG_COLD_DATA, NULL, false);
648 
649         fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi), newaddr,
650                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
651         if (!fio.encrypted_page) {
652                 err = -ENOMEM;
653                 goto recover_block;
654         }
655 
656         err = f2fs_submit_page_bio(&fio);
657         if (err)
658                 goto put_page_out;
659 
660         /* write page */
661         lock_page(fio.encrypted_page);
662 
663         if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi))) {
664                 err = -EIO;
665                 goto put_page_out;
666         }
667         if (unlikely(!PageUptodate(fio.encrypted_page))) {
668                 err = -EIO;
669                 goto put_page_out;
670         }
671 
672         set_page_dirty(fio.encrypted_page);
673         f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
674         if (clear_page_dirty_for_io(fio.encrypted_page))
675                 dec_page_count(fio.sbi, F2FS_DIRTY_META);
676 
677         set_page_writeback(fio.encrypted_page);
678 
679         /* allocate block address */
680         f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
681 
682         fio.op = REQ_OP_WRITE;
683         fio.op_flags = REQ_SYNC;
684         fio.new_blkaddr = newaddr;
685         f2fs_submit_page_write(&fio);
686 
687         f2fs_update_data_blkaddr(&dn, newaddr);
688         set_inode_flag(inode, FI_APPEND_WRITE);
689         if (page->index == 0)
690                 set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
691 put_page_out:
692         f2fs_put_page(fio.encrypted_page, 1);
693 recover_block:
694         if (err)
695                 __f2fs_replace_block(fio.sbi, &sum, newaddr, fio.old_blkaddr,
696                                                                 true, true);
697 put_out:
698         f2fs_put_dnode(&dn);
699 out:
700         f2fs_put_page(page, 1);
701 }
702 
703 static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
704                                                         unsigned int segno, int off)
705 {
706         struct page *page;
707 
708         page = get_lock_data_page(inode, bidx, true);
709         if (IS_ERR(page))
710                 return;
711 
712         if (!check_valid_map(F2FS_I_SB(inode), segno, off))
713                 goto out;
714 
715         if (f2fs_is_atomic_file(inode))
716                 goto out;
717 
718         if (gc_type == BG_GC) {
719                 if (PageWriteback(page))
720                         goto out;
721                 set_page_dirty(page);
722                 set_cold_data(page);
723         } else {
724                 struct f2fs_io_info fio = {
725                         .sbi = F2FS_I_SB(inode),
726                         .type = DATA,
727                         .temp = COLD,
728                         .op = REQ_OP_WRITE,
729                         .op_flags = REQ_SYNC,
730                         .old_blkaddr = NULL_ADDR,
731                         .page = page,
732                         .encrypted_page = NULL,
733                         .need_lock = LOCK_REQ,
734                 };
735                 bool is_dirty = PageDirty(page);
736                 int err;
737 
738 retry:
739                 set_page_dirty(page);
740                 f2fs_wait_on_page_writeback(page, DATA, true);
741                 if (clear_page_dirty_for_io(page)) {
742                         inode_dec_dirty_pages(inode);
743                         remove_dirty_inode(inode);
744                 }
745 
746                 set_cold_data(page);
747 
748                 err = do_write_data_page(&fio);
749                 if (err == -ENOMEM && is_dirty) {
750                         congestion_wait(BLK_RW_ASYNC, HZ/50);
751                         goto retry;
752                 }
753         }
754 out:
755         f2fs_put_page(page, 1);
756 }
757 
758 /*
759  * This function tries to get parent node of victim data block, and identifies
760  * data block validity. If the block is valid, copy that with cold status and
761  * modify parent node.
762  * If the parent node is not valid or the data block address is different,
763  * the victim data block is ignored.
764  */
765 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
766                 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
767 {
768         struct super_block *sb = sbi->sb;
769         struct f2fs_summary *entry;
770         block_t start_addr;
771         int off;
772         int phase = 0;
773 
774         start_addr = START_BLOCK(sbi, segno);
775 
776 next_step:
777         entry = sum;
778 
779         for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
780                 struct page *data_page;
781                 struct inode *inode;
782                 struct node_info dni; /* dnode info for the data */
783                 unsigned int ofs_in_node, nofs;
784                 block_t start_bidx;
785                 nid_t nid = le32_to_cpu(entry->nid);
786 
787                 /* stop BG_GC if there is not enough free sections. */
788                 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0))
789                         return;
790 
791                 if (check_valid_map(sbi, segno, off) == 0)
792                         continue;
793 
794                 if (phase == 0) {
795                         ra_meta_pages(sbi, NAT_BLOCK_OFFSET(nid), 1,
796                                                         META_NAT, true);
797                         continue;
798                 }
799 
800                 if (phase == 1) {
801                         ra_node_page(sbi, nid);
802                         continue;
803                 }
804 
805                 /* Get an inode by ino with checking validity */
806                 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
807                         continue;
808 
809                 if (phase == 2) {
810                         ra_node_page(sbi, dni.ino);
811                         continue;
812                 }
813 
814                 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
815 
816                 if (phase == 3) {
817                         inode = f2fs_iget(sb, dni.ino);
818                         if (IS_ERR(inode) || is_bad_inode(inode))
819                                 continue;
820 
821                         /* if encrypted inode, let's go phase 3 */
822                         if (f2fs_encrypted_inode(inode) &&
823                                                 S_ISREG(inode->i_mode)) {
824                                 add_gc_inode(gc_list, inode);
825                                 continue;
826                         }
827 
828                         start_bidx = start_bidx_of_node(nofs, inode);
829                         data_page = get_read_data_page(inode,
830                                         start_bidx + ofs_in_node, REQ_RAHEAD,
831                                         true);
832                         if (IS_ERR(data_page)) {
833                                 iput(inode);
834                                 continue;
835                         }
836 
837                         f2fs_put_page(data_page, 0);
838                         add_gc_inode(gc_list, inode);
839                         continue;
840                 }
841 
842                 /* phase 4 */
843                 inode = find_gc_inode(gc_list, dni.ino);
844                 if (inode) {
845                         struct f2fs_inode_info *fi = F2FS_I(inode);
846                         bool locked = false;
847 
848                         if (S_ISREG(inode->i_mode)) {
849                                 if (!down_write_trylock(&fi->dio_rwsem[READ]))
850                                         continue;
851                                 if (!down_write_trylock(
852                                                 &fi->dio_rwsem[WRITE])) {
853                                         up_write(&fi->dio_rwsem[READ]);
854                                         continue;
855                                 }
856                                 locked = true;
857                         }
858 
859                         start_bidx = start_bidx_of_node(nofs, inode)
860                                                                 + ofs_in_node;
861                         if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
862                                 move_encrypted_block(inode, start_bidx, segno, off);
863                         else
864                                 move_data_page(inode, start_bidx, gc_type, segno, off);
865 
866                         if (locked) {
867                                 up_write(&fi->dio_rwsem[WRITE]);
868                                 up_write(&fi->dio_rwsem[READ]);
869                         }
870 
871                         stat_inc_data_blk_count(sbi, 1, gc_type);
872                 }
873         }
874 
875         if (++phase < 5)
876                 goto next_step;
877 }
878 
879 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
880                         int gc_type)
881 {
882         struct sit_info *sit_i = SIT_I(sbi);
883         int ret;
884 
885         mutex_lock(&sit_i->sentry_lock);
886         ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
887                                               NO_CHECK_TYPE, LFS);
888         mutex_unlock(&sit_i->sentry_lock);
889         return ret;
890 }
891 
892 static int do_garbage_collect(struct f2fs_sb_info *sbi,
893                                 unsigned int start_segno,
894                                 struct gc_inode_list *gc_list, int gc_type)
895 {
896         struct page *sum_page;
897         struct f2fs_summary_block *sum;
898         struct blk_plug plug;
899         unsigned int segno = start_segno;
900         unsigned int end_segno = start_segno + sbi->segs_per_sec;
901         int sec_freed = 0;
902         unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
903                                                 SUM_TYPE_DATA : SUM_TYPE_NODE;
904 
905         /* readahead multi ssa blocks those have contiguous address */
906         if (sbi->segs_per_sec > 1)
907                 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
908                                         sbi->segs_per_sec, META_SSA, true);
909 
910         /* reference all summary page */
911         while (segno < end_segno) {
912                 sum_page = get_sum_page(sbi, segno++);
913                 unlock_page(sum_page);
914         }
915 
916         blk_start_plug(&plug);
917 
918         for (segno = start_segno; segno < end_segno; segno++) {
919 
920                 /* find segment summary of victim */
921                 sum_page = find_get_page(META_MAPPING(sbi),
922                                         GET_SUM_BLOCK(sbi, segno));
923                 f2fs_put_page(sum_page, 0);
924 
925                 if (get_valid_blocks(sbi, segno, false) == 0 ||
926                                 !PageUptodate(sum_page) ||
927                                 unlikely(f2fs_cp_error(sbi)))
928                         goto next;
929 
930                 sum = page_address(sum_page);
931                 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
932 
933                 /*
934                  * this is to avoid deadlock:
935                  * - lock_page(sum_page)         - f2fs_replace_block
936                  *  - check_valid_map()            - mutex_lock(sentry_lock)
937                  *   - mutex_lock(sentry_lock)     - change_curseg()
938                  *                                  - lock_page(sum_page)
939                  */
940                 if (type == SUM_TYPE_NODE)
941                         gc_node_segment(sbi, sum->entries, segno, gc_type);
942                 else
943                         gc_data_segment(sbi, sum->entries, gc_list, segno,
944                                                                 gc_type);
945 
946                 stat_inc_seg_count(sbi, type, gc_type);
947 next:
948                 f2fs_put_page(sum_page, 0);
949         }
950 
951         if (gc_type == FG_GC)
952                 f2fs_submit_merged_write(sbi,
953                                 (type == SUM_TYPE_NODE) ? NODE : DATA);
954 
955         blk_finish_plug(&plug);
956 
957         if (gc_type == FG_GC &&
958                 get_valid_blocks(sbi, start_segno, true) == 0)
959                 sec_freed = 1;
960 
961         stat_inc_call_count(sbi->stat_info);
962 
963         return sec_freed;
964 }
965 
966 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
967                         bool background, unsigned int segno)
968 {
969         int gc_type = sync ? FG_GC : BG_GC;
970         int sec_freed = 0;
971         int ret;
972         struct cp_control cpc;
973         unsigned int init_segno = segno;
974         struct gc_inode_list gc_list = {
975                 .ilist = LIST_HEAD_INIT(gc_list.ilist),
976                 .iroot = RADIX_TREE_INIT(GFP_NOFS),
977         };
978 
979         cpc.reason = __get_cp_reason(sbi);
980 gc_more:
981         if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE))) {
982                 ret = -EINVAL;
983                 goto stop;
984         }
985         if (unlikely(f2fs_cp_error(sbi))) {
986                 ret = -EIO;
987                 goto stop;
988         }
989 
990         if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0, 0)) {
991                 /*
992                  * For example, if there are many prefree_segments below given
993                  * threshold, we can make them free by checkpoint. Then, we
994                  * secure free segments which doesn't need fggc any more.
995                  */
996                 if (prefree_segments(sbi)) {
997                         ret = write_checkpoint(sbi, &cpc);
998                         if (ret)
999                                 goto stop;
1000                 }
1001                 if (has_not_enough_free_secs(sbi, 0, 0))
1002                         gc_type = FG_GC;
1003         }
1004 
1005         ret = -EINVAL;
1006         /* f2fs_balance_fs doesn't need to do BG_GC in critical path. */
1007         if (gc_type == BG_GC && !background)
1008                 goto stop;
1009         if (!__get_victim(sbi, &segno, gc_type))
1010                 goto stop;
1011         ret = 0;
1012 
1013         if (do_garbage_collect(sbi, segno, &gc_list, gc_type) &&
1014                         gc_type == FG_GC)
1015                 sec_freed++;
1016 
1017         if (gc_type == FG_GC)
1018                 sbi->cur_victim_sec = NULL_SEGNO;
1019 
1020         if (!sync) {
1021                 if (has_not_enough_free_secs(sbi, sec_freed, 0)) {
1022                         segno = NULL_SEGNO;
1023                         goto gc_more;
1024                 }
1025 
1026                 if (gc_type == FG_GC)
1027                         ret = write_checkpoint(sbi, &cpc);
1028         }
1029 stop:
1030         SIT_I(sbi)->last_victim[ALLOC_NEXT] = 0;
1031         SIT_I(sbi)->last_victim[FLUSH_DEVICE] = init_segno;
1032         mutex_unlock(&sbi->gc_mutex);
1033 
1034         put_gc_inode(&gc_list);
1035 
1036         if (sync)
1037                 ret = sec_freed ? 0 : -EAGAIN;
1038         return ret;
1039 }
1040 
1041 void build_gc_manager(struct f2fs_sb_info *sbi)
1042 {
1043         u64 main_count, resv_count, ovp_count;
1044 
1045         DIRTY_I(sbi)->v_ops = &default_v_ops;
1046 
1047         /* threshold of # of valid blocks in a section for victims of FG_GC */
1048         main_count = SM_I(sbi)->main_segments << sbi->log_blocks_per_seg;
1049         resv_count = SM_I(sbi)->reserved_segments << sbi->log_blocks_per_seg;
1050         ovp_count = SM_I(sbi)->ovp_segments << sbi->log_blocks_per_seg;
1051 
1052         sbi->fggc_threshold = div64_u64((main_count - ovp_count) *
1053                                 BLKS_PER_SEC(sbi), (main_count - resv_count));
1054 
1055         /* give warm/cold data area from slower device */
1056         if (sbi->s_ndevs && sbi->segs_per_sec == 1)
1057                 SIT_I(sbi)->last_victim[ALLOC_NEXT] =
1058                                 GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
1059 }
1060 

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