4 * Copyright (c) 2012 Samsung Electronics Co., Ltd.
5 * http://www.samsung.com/
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.
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>
24 #include <trace/events/f2fs.h>
26 static int gc_thread_func(void *data)
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;
33 wait_ms = gc_th->min_sleep_time;
39 wait_event_interruptible_timeout(*wq,
40 kthread_should_stop(),
41 msecs_to_jiffies(wait_ms));
42 if (kthread_should_stop())
45 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
46 increase_sleep_time(gc_th, &wait_ms);
51 * [GC triggering condition]
52 * 0. GC is not conducted currently.
53 * 1. There are enough dirty segments.
54 * 2. IO subsystem is idle by checking the # of writeback pages.
55 * 3. IO subsystem is idle by checking the # of requests in
56 * bdev's request list.
58 * Note) We have to avoid triggering GCs frequently.
59 * Because it is possible that some segments can be
60 * invalidated soon after by user update or deletion.
61 * So, I'd like to wait some time to collect dirty segments.
63 if (!mutex_trylock(&sbi->gc_mutex))
67 increase_sleep_time(gc_th, &wait_ms);
68 mutex_unlock(&sbi->gc_mutex);
72 if (has_enough_invalid_blocks(sbi))
73 decrease_sleep_time(gc_th, &wait_ms);
75 increase_sleep_time(gc_th, &wait_ms);
77 stat_inc_bggc_count(sbi);
79 /* if return value is not zero, no victim was selected */
80 if (f2fs_gc(sbi, test_opt(sbi, FORCE_FG_GC)))
81 wait_ms = gc_th->no_gc_sleep_time;
83 trace_f2fs_background_gc(sbi->sb, wait_ms,
84 prefree_segments(sbi), free_segments(sbi));
86 /* balancing f2fs's metadata periodically */
87 f2fs_balance_fs_bg(sbi);
89 } while (!kthread_should_stop());
93 int start_gc_thread(struct f2fs_sb_info *sbi)
95 struct f2fs_gc_kthread *gc_th;
96 dev_t dev = sbi->sb->s_bdev->bd_dev;
99 gc_th = kmalloc(sizeof(struct f2fs_gc_kthread), GFP_KERNEL);
105 gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
106 gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
107 gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
111 sbi->gc_thread = gc_th;
112 init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
113 sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
114 "f2fs_gc-%u:%u", MAJOR(dev), MINOR(dev));
115 if (IS_ERR(gc_th->f2fs_gc_task)) {
116 err = PTR_ERR(gc_th->f2fs_gc_task);
118 sbi->gc_thread = NULL;
124 void stop_gc_thread(struct f2fs_sb_info *sbi)
126 struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
129 kthread_stop(gc_th->f2fs_gc_task);
131 sbi->gc_thread = NULL;
134 static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
136 int gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
138 if (gc_th && gc_th->gc_idle) {
139 if (gc_th->gc_idle == 1)
141 else if (gc_th->gc_idle == 2)
147 static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
148 int type, struct victim_sel_policy *p)
150 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
152 if (p->alloc_mode == SSR) {
153 p->gc_mode = GC_GREEDY;
154 p->dirty_segmap = dirty_i->dirty_segmap[type];
155 p->max_search = dirty_i->nr_dirty[type];
158 p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
159 p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
160 p->max_search = dirty_i->nr_dirty[DIRTY];
161 p->ofs_unit = sbi->segs_per_sec;
164 if (p->max_search > sbi->max_victim_search)
165 p->max_search = sbi->max_victim_search;
167 p->offset = sbi->last_victim[p->gc_mode];
170 static unsigned int get_max_cost(struct f2fs_sb_info *sbi,
171 struct victim_sel_policy *p)
173 /* SSR allocates in a segment unit */
174 if (p->alloc_mode == SSR)
175 return sbi->blocks_per_seg;
176 if (p->gc_mode == GC_GREEDY)
177 return sbi->blocks_per_seg * p->ofs_unit;
178 else if (p->gc_mode == GC_CB)
180 else /* No other gc_mode */
184 static unsigned int check_bg_victims(struct f2fs_sb_info *sbi)
186 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
190 * If the gc_type is FG_GC, we can select victim segments
191 * selected by background GC before.
192 * Those segments guarantee they have small valid blocks.
194 for_each_set_bit(secno, dirty_i->victim_secmap, MAIN_SECS(sbi)) {
195 if (sec_usage_check(sbi, secno))
197 clear_bit(secno, dirty_i->victim_secmap);
198 return secno * sbi->segs_per_sec;
203 static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
205 struct sit_info *sit_i = SIT_I(sbi);
206 unsigned int secno = GET_SECNO(sbi, segno);
207 unsigned int start = secno * sbi->segs_per_sec;
208 unsigned long long mtime = 0;
209 unsigned int vblocks;
210 unsigned char age = 0;
214 for (i = 0; i < sbi->segs_per_sec; i++)
215 mtime += get_seg_entry(sbi, start + i)->mtime;
216 vblocks = get_valid_blocks(sbi, segno, sbi->segs_per_sec);
218 mtime = div_u64(mtime, sbi->segs_per_sec);
219 vblocks = div_u64(vblocks, sbi->segs_per_sec);
221 u = (vblocks * 100) >> sbi->log_blocks_per_seg;
223 /* Handle if the system time has changed by the user */
224 if (mtime < sit_i->min_mtime)
225 sit_i->min_mtime = mtime;
226 if (mtime > sit_i->max_mtime)
227 sit_i->max_mtime = mtime;
228 if (sit_i->max_mtime != sit_i->min_mtime)
229 age = 100 - div64_u64(100 * (mtime - sit_i->min_mtime),
230 sit_i->max_mtime - sit_i->min_mtime);
232 return UINT_MAX - ((100 * (100 - u) * age) / (100 + u));
235 static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
236 unsigned int segno, struct victim_sel_policy *p)
238 if (p->alloc_mode == SSR)
239 return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
241 /* alloc_mode == LFS */
242 if (p->gc_mode == GC_GREEDY)
243 return get_valid_blocks(sbi, segno, sbi->segs_per_sec);
245 return get_cb_cost(sbi, segno);
248 static unsigned int count_bits(const unsigned long *addr,
249 unsigned int offset, unsigned int len)
251 unsigned int end = offset + len, sum = 0;
253 while (offset < end) {
254 if (test_bit(offset++, addr))
261 * This function is called from two paths.
262 * One is garbage collection and the other is SSR segment selection.
263 * When it is called during GC, it just gets a victim segment
264 * and it does not remove it from dirty seglist.
265 * When it is called from SSR segment selection, it finds a segment
266 * which has minimum valid blocks and removes it from dirty seglist.
268 static int get_victim_by_default(struct f2fs_sb_info *sbi,
269 unsigned int *result, int gc_type, int type, char alloc_mode)
271 struct dirty_seglist_info *dirty_i = DIRTY_I(sbi);
272 struct victim_sel_policy p;
273 unsigned int secno, max_cost;
274 unsigned int last_segment = MAIN_SEGS(sbi);
275 unsigned int nsearched = 0;
277 mutex_lock(&dirty_i->seglist_lock);
279 p.alloc_mode = alloc_mode;
280 select_policy(sbi, gc_type, type, &p);
282 p.min_segno = NULL_SEGNO;
283 p.min_cost = max_cost = get_max_cost(sbi, &p);
285 if (p.max_search == 0)
288 if (p.alloc_mode == LFS && gc_type == FG_GC) {
289 p.min_segno = check_bg_victims(sbi);
290 if (p.min_segno != NULL_SEGNO)
298 segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
299 if (segno >= last_segment) {
300 if (sbi->last_victim[p.gc_mode]) {
301 last_segment = sbi->last_victim[p.gc_mode];
302 sbi->last_victim[p.gc_mode] = 0;
309 p.offset = segno + p.ofs_unit;
310 if (p.ofs_unit > 1) {
311 p.offset -= segno % p.ofs_unit;
312 nsearched += count_bits(p.dirty_segmap,
313 p.offset - p.ofs_unit,
320 secno = GET_SECNO(sbi, segno);
322 if (sec_usage_check(sbi, secno))
324 if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
327 cost = get_gc_cost(sbi, segno, &p);
329 if (p.min_cost > cost) {
334 if (nsearched >= p.max_search) {
335 sbi->last_victim[p.gc_mode] = segno;
339 if (p.min_segno != NULL_SEGNO) {
341 if (p.alloc_mode == LFS) {
342 secno = GET_SECNO(sbi, p.min_segno);
343 if (gc_type == FG_GC)
344 sbi->cur_victim_sec = secno;
346 set_bit(secno, dirty_i->victim_secmap);
348 *result = (p.min_segno / p.ofs_unit) * p.ofs_unit;
350 trace_f2fs_get_victim(sbi->sb, type, gc_type, &p,
352 prefree_segments(sbi), free_segments(sbi));
355 mutex_unlock(&dirty_i->seglist_lock);
357 return (p.min_segno == NULL_SEGNO) ? 0 : 1;
360 static const struct victim_selection default_v_ops = {
361 .get_victim = get_victim_by_default,
364 static struct inode *find_gc_inode(struct gc_inode_list *gc_list, nid_t ino)
366 struct inode_entry *ie;
368 ie = radix_tree_lookup(&gc_list->iroot, ino);
374 static void add_gc_inode(struct gc_inode_list *gc_list, struct inode *inode)
376 struct inode_entry *new_ie;
378 if (inode == find_gc_inode(gc_list, inode->i_ino)) {
382 new_ie = f2fs_kmem_cache_alloc(inode_entry_slab, GFP_NOFS);
383 new_ie->inode = inode;
385 f2fs_radix_tree_insert(&gc_list->iroot, inode->i_ino, new_ie);
386 list_add_tail(&new_ie->list, &gc_list->ilist);
389 static void put_gc_inode(struct gc_inode_list *gc_list)
391 struct inode_entry *ie, *next_ie;
392 list_for_each_entry_safe(ie, next_ie, &gc_list->ilist, list) {
393 radix_tree_delete(&gc_list->iroot, ie->inode->i_ino);
396 kmem_cache_free(inode_entry_slab, ie);
400 static int check_valid_map(struct f2fs_sb_info *sbi,
401 unsigned int segno, int offset)
403 struct sit_info *sit_i = SIT_I(sbi);
404 struct seg_entry *sentry;
407 mutex_lock(&sit_i->sentry_lock);
408 sentry = get_seg_entry(sbi, segno);
409 ret = f2fs_test_bit(offset, sentry->cur_valid_map);
410 mutex_unlock(&sit_i->sentry_lock);
415 * This function compares node address got in summary with that in NAT.
416 * On validity, copy that node with cold status, otherwise (invalid node)
419 static void gc_node_segment(struct f2fs_sb_info *sbi,
420 struct f2fs_summary *sum, unsigned int segno, int gc_type)
423 struct f2fs_summary *entry;
427 start_addr = START_BLOCK(sbi, segno);
432 for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
433 nid_t nid = le32_to_cpu(entry->nid);
434 struct page *node_page;
437 /* stop BG_GC if there is not enough free sections. */
438 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
441 if (check_valid_map(sbi, segno, off) == 0)
445 ra_node_page(sbi, nid);
448 node_page = get_node_page(sbi, nid);
449 if (IS_ERR(node_page))
452 /* block may become invalid during get_node_page */
453 if (check_valid_map(sbi, segno, off) == 0) {
454 f2fs_put_page(node_page, 1);
458 get_node_info(sbi, nid, &ni);
459 if (ni.blk_addr != start_addr + off) {
460 f2fs_put_page(node_page, 1);
464 /* set page dirty and write it */
465 if (gc_type == FG_GC) {
466 f2fs_wait_on_page_writeback(node_page, NODE, true);
467 set_page_dirty(node_page);
469 if (!PageWriteback(node_page))
470 set_page_dirty(node_page);
472 f2fs_put_page(node_page, 1);
473 stat_inc_node_blk_count(sbi, 1, gc_type);
483 * Calculate start block index indicating the given node offset.
484 * Be careful, caller should give this node offset only indicating direct node
485 * blocks. If any node offsets, which point the other types of node blocks such
486 * as indirect or double indirect node blocks, are given, it must be a caller's
489 block_t start_bidx_of_node(unsigned int node_ofs, struct inode *inode)
491 unsigned int indirect_blks = 2 * NIDS_PER_BLOCK + 4;
499 } else if (node_ofs <= indirect_blks) {
500 int dec = (node_ofs - 4) / (NIDS_PER_BLOCK + 1);
501 bidx = node_ofs - 2 - dec;
503 int dec = (node_ofs - indirect_blks - 3) / (NIDS_PER_BLOCK + 1);
504 bidx = node_ofs - 5 - dec;
506 return bidx * ADDRS_PER_BLOCK + ADDRS_PER_INODE(inode);
509 static bool is_alive(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
510 struct node_info *dni, block_t blkaddr, unsigned int *nofs)
512 struct page *node_page;
514 unsigned int ofs_in_node;
515 block_t source_blkaddr;
517 nid = le32_to_cpu(sum->nid);
518 ofs_in_node = le16_to_cpu(sum->ofs_in_node);
520 node_page = get_node_page(sbi, nid);
521 if (IS_ERR(node_page))
524 get_node_info(sbi, nid, dni);
526 if (sum->version != dni->version) {
527 f2fs_put_page(node_page, 1);
531 *nofs = ofs_of_node(node_page);
532 source_blkaddr = datablock_addr(node_page, ofs_in_node);
533 f2fs_put_page(node_page, 1);
535 if (source_blkaddr != blkaddr)
540 static void move_encrypted_block(struct inode *inode, block_t bidx)
542 struct f2fs_io_info fio = {
543 .sbi = F2FS_I_SB(inode),
546 .encrypted_page = NULL,
548 struct dnode_of_data dn;
549 struct f2fs_summary sum;
554 /* do not read out */
555 page = f2fs_grab_cache_page(inode->i_mapping, bidx, false);
559 set_new_dnode(&dn, inode, NULL, NULL, 0);
560 err = get_dnode_of_data(&dn, bidx, LOOKUP_NODE);
564 if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
565 ClearPageUptodate(page);
570 * don't cache encrypted data into meta inode until previous dirty
571 * data were writebacked to avoid racing between GC and flush.
573 f2fs_wait_on_page_writeback(page, DATA, true);
575 get_node_info(fio.sbi, dn.nid, &ni);
576 set_summary(&sum, dn.nid, dn.ofs_in_node, ni.version);
580 fio.blk_addr = dn.data_blkaddr;
582 fio.encrypted_page = pagecache_get_page(META_MAPPING(fio.sbi),
586 if (!fio.encrypted_page)
589 err = f2fs_submit_page_bio(&fio);
594 lock_page(fio.encrypted_page);
596 if (unlikely(!PageUptodate(fio.encrypted_page)))
598 if (unlikely(fio.encrypted_page->mapping != META_MAPPING(fio.sbi)))
601 set_page_dirty(fio.encrypted_page);
602 f2fs_wait_on_page_writeback(fio.encrypted_page, DATA, true);
603 if (clear_page_dirty_for_io(fio.encrypted_page))
604 dec_page_count(fio.sbi, F2FS_DIRTY_META);
606 set_page_writeback(fio.encrypted_page);
608 /* allocate block address */
609 f2fs_wait_on_page_writeback(dn.node_page, NODE, true);
610 allocate_data_block(fio.sbi, NULL, fio.blk_addr,
611 &fio.blk_addr, &sum, CURSEG_COLD_DATA);
613 f2fs_submit_page_mbio(&fio);
615 dn.data_blkaddr = fio.blk_addr;
616 set_data_blkaddr(&dn);
617 f2fs_update_extent_cache(&dn);
618 set_inode_flag(F2FS_I(inode), FI_APPEND_WRITE);
619 if (page->index == 0)
620 set_inode_flag(F2FS_I(inode), FI_FIRST_BLOCK_WRITTEN);
622 f2fs_put_page(fio.encrypted_page, 1);
626 f2fs_put_page(page, 1);
629 static void move_data_page(struct inode *inode, block_t bidx, int gc_type)
633 page = get_lock_data_page(inode, bidx, true);
637 if (gc_type == BG_GC) {
638 if (PageWriteback(page))
640 set_page_dirty(page);
643 struct f2fs_io_info fio = {
644 .sbi = F2FS_I_SB(inode),
648 .encrypted_page = NULL,
650 set_page_dirty(page);
651 f2fs_wait_on_page_writeback(page, DATA, true);
652 if (clear_page_dirty_for_io(page))
653 inode_dec_dirty_pages(inode);
655 do_write_data_page(&fio);
656 clear_cold_data(page);
659 f2fs_put_page(page, 1);
663 * This function tries to get parent node of victim data block, and identifies
664 * data block validity. If the block is valid, copy that with cold status and
665 * modify parent node.
666 * If the parent node is not valid or the data block address is different,
667 * the victim data block is ignored.
669 static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
670 struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
672 struct super_block *sb = sbi->sb;
673 struct f2fs_summary *entry;
678 start_addr = START_BLOCK(sbi, segno);
683 for (off = 0; off < sbi->blocks_per_seg; off++, entry++) {
684 struct page *data_page;
686 struct node_info dni; /* dnode info for the data */
687 unsigned int ofs_in_node, nofs;
690 /* stop BG_GC if there is not enough free sections. */
691 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
694 if (check_valid_map(sbi, segno, off) == 0)
698 ra_node_page(sbi, le32_to_cpu(entry->nid));
702 /* Get an inode by ino with checking validity */
703 if (!is_alive(sbi, entry, &dni, start_addr + off, &nofs))
707 ra_node_page(sbi, dni.ino);
711 ofs_in_node = le16_to_cpu(entry->ofs_in_node);
714 inode = f2fs_iget(sb, dni.ino);
715 if (IS_ERR(inode) || is_bad_inode(inode))
718 /* if encrypted inode, let's go phase 3 */
719 if (f2fs_encrypted_inode(inode) &&
720 S_ISREG(inode->i_mode)) {
721 add_gc_inode(gc_list, inode);
725 start_bidx = start_bidx_of_node(nofs, inode);
726 data_page = get_read_data_page(inode,
727 start_bidx + ofs_in_node, READA, true);
728 if (IS_ERR(data_page)) {
733 f2fs_put_page(data_page, 0);
734 add_gc_inode(gc_list, inode);
739 inode = find_gc_inode(gc_list, dni.ino);
741 start_bidx = start_bidx_of_node(nofs, inode)
743 if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
744 move_encrypted_block(inode, start_bidx);
746 move_data_page(inode, start_bidx, gc_type);
747 stat_inc_data_blk_count(sbi, 1, gc_type);
755 static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
758 struct sit_info *sit_i = SIT_I(sbi);
761 mutex_lock(&sit_i->sentry_lock);
762 ret = DIRTY_I(sbi)->v_ops->get_victim(sbi, victim, gc_type,
764 mutex_unlock(&sit_i->sentry_lock);
768 static int do_garbage_collect(struct f2fs_sb_info *sbi,
769 unsigned int start_segno,
770 struct gc_inode_list *gc_list, int gc_type)
772 struct page *sum_page;
773 struct f2fs_summary_block *sum;
774 struct blk_plug plug;
775 unsigned int segno = start_segno;
776 unsigned int end_segno = start_segno + sbi->segs_per_sec;
778 unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
779 SUM_TYPE_DATA : SUM_TYPE_NODE;
781 /* readahead multi ssa blocks those have contiguous address */
782 if (sbi->segs_per_sec > 1)
783 ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
784 sbi->segs_per_sec, META_SSA, true);
786 /* reference all summary page */
787 while (segno < end_segno) {
788 sum_page = get_sum_page(sbi, segno++);
789 unlock_page(sum_page);
792 blk_start_plug(&plug);
794 for (segno = start_segno; segno < end_segno; segno++) {
795 /* find segment summary of victim */
796 sum_page = find_get_page(META_MAPPING(sbi),
797 GET_SUM_BLOCK(sbi, segno));
798 f2fs_bug_on(sbi, !PageUptodate(sum_page));
799 f2fs_put_page(sum_page, 0);
801 sum = page_address(sum_page);
802 f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
805 * this is to avoid deadlock:
806 * - lock_page(sum_page) - f2fs_replace_block
807 * - check_valid_map() - mutex_lock(sentry_lock)
808 * - mutex_lock(sentry_lock) - change_curseg()
809 * - lock_page(sum_page)
812 if (type == SUM_TYPE_NODE)
813 gc_node_segment(sbi, sum->entries, segno, gc_type);
815 gc_data_segment(sbi, sum->entries, gc_list, segno,
818 stat_inc_seg_count(sbi, type, gc_type);
819 stat_inc_call_count(sbi->stat_info);
821 f2fs_put_page(sum_page, 0);
824 if (gc_type == FG_GC) {
825 if (type == SUM_TYPE_NODE) {
826 struct writeback_control wbc = {
827 .sync_mode = WB_SYNC_ALL,
828 .nr_to_write = LONG_MAX,
831 sync_node_pages(sbi, 0, &wbc);
833 f2fs_submit_merged_bio(sbi, DATA, WRITE);
837 blk_finish_plug(&plug);
839 if (gc_type == FG_GC) {
840 while (start_segno < end_segno)
841 if (get_valid_blocks(sbi, start_segno++, 1) == 0)
847 int f2fs_gc(struct f2fs_sb_info *sbi, bool sync)
850 int gc_type = sync ? FG_GC : BG_GC;
851 int sec_freed = 0, seg_freed;
853 struct cp_control cpc;
854 struct gc_inode_list gc_list = {
855 .ilist = LIST_HEAD_INIT(gc_list.ilist),
856 .iroot = RADIX_TREE_INIT(GFP_NOFS),
859 cpc.reason = __get_cp_reason(sbi);
863 if (unlikely(!(sbi->sb->s_flags & MS_ACTIVE)))
865 if (unlikely(f2fs_cp_error(sbi))) {
870 if (gc_type == BG_GC && has_not_enough_free_secs(sbi, sec_freed)) {
873 * If there is no victim and no prefree segment but still not
874 * enough free sections, we should flush dent/node blocks and do
875 * garbage collections.
877 if (__get_victim(sbi, &segno, gc_type) || prefree_segments(sbi))
878 write_checkpoint(sbi, &cpc);
879 else if (has_not_enough_free_secs(sbi, 0))
880 write_checkpoint(sbi, &cpc);
883 if (segno == NULL_SEGNO && !__get_victim(sbi, &segno, gc_type))
887 seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
889 if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
892 if (gc_type == FG_GC)
893 sbi->cur_victim_sec = NULL_SEGNO;
896 if (has_not_enough_free_secs(sbi, sec_freed))
899 if (gc_type == FG_GC)
900 write_checkpoint(sbi, &cpc);
903 mutex_unlock(&sbi->gc_mutex);
905 put_gc_inode(&gc_list);
908 ret = sec_freed ? 0 : -EAGAIN;
912 void build_gc_manager(struct f2fs_sb_info *sbi)
914 DIRTY_I(sbi)->v_ops = &default_v_ops;