xref: /openbmc/linux/fs/f2fs/node.c (revision 0a8165d7c2cf1395059db20ab07665baf3758fcd)
1 /*
2  * fs/f2fs/node.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/f2fs_fs.h>
13 #include <linux/mpage.h>
14 #include <linux/backing-dev.h>
15 #include <linux/blkdev.h>
16 #include <linux/pagevec.h>
17 #include <linux/swap.h>
18 
19 #include "f2fs.h"
20 #include "node.h"
21 #include "segment.h"
22 
23 static struct kmem_cache *nat_entry_slab;
24 static struct kmem_cache *free_nid_slab;
25 
26 static void clear_node_page_dirty(struct page *page)
27 {
28 	struct address_space *mapping = page->mapping;
29 	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
30 	unsigned int long flags;
31 
32 	if (PageDirty(page)) {
33 		spin_lock_irqsave(&mapping->tree_lock, flags);
34 		radix_tree_tag_clear(&mapping->page_tree,
35 				page_index(page),
36 				PAGECACHE_TAG_DIRTY);
37 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
38 
39 		clear_page_dirty_for_io(page);
40 		dec_page_count(sbi, F2FS_DIRTY_NODES);
41 	}
42 	ClearPageUptodate(page);
43 }
44 
45 static struct page *get_current_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
46 {
47 	pgoff_t index = current_nat_addr(sbi, nid);
48 	return get_meta_page(sbi, index);
49 }
50 
51 static struct page *get_next_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
52 {
53 	struct page *src_page;
54 	struct page *dst_page;
55 	pgoff_t src_off;
56 	pgoff_t dst_off;
57 	void *src_addr;
58 	void *dst_addr;
59 	struct f2fs_nm_info *nm_i = NM_I(sbi);
60 
61 	src_off = current_nat_addr(sbi, nid);
62 	dst_off = next_nat_addr(sbi, src_off);
63 
64 	/* get current nat block page with lock */
65 	src_page = get_meta_page(sbi, src_off);
66 
67 	/* Dirty src_page means that it is already the new target NAT page. */
68 	if (PageDirty(src_page))
69 		return src_page;
70 
71 	dst_page = grab_meta_page(sbi, dst_off);
72 
73 	src_addr = page_address(src_page);
74 	dst_addr = page_address(dst_page);
75 	memcpy(dst_addr, src_addr, PAGE_CACHE_SIZE);
76 	set_page_dirty(dst_page);
77 	f2fs_put_page(src_page, 1);
78 
79 	set_to_next_nat(nm_i, nid);
80 
81 	return dst_page;
82 }
83 
84 /*
85  * Readahead NAT pages
86  */
87 static void ra_nat_pages(struct f2fs_sb_info *sbi, int nid)
88 {
89 	struct address_space *mapping = sbi->meta_inode->i_mapping;
90 	struct f2fs_nm_info *nm_i = NM_I(sbi);
91 	struct page *page;
92 	pgoff_t index;
93 	int i;
94 
95 	for (i = 0; i < FREE_NID_PAGES; i++, nid += NAT_ENTRY_PER_BLOCK) {
96 		if (nid >= nm_i->max_nid)
97 			nid = 0;
98 		index = current_nat_addr(sbi, nid);
99 
100 		page = grab_cache_page(mapping, index);
101 		if (!page)
102 			continue;
103 		if (f2fs_readpage(sbi, page, index, READ)) {
104 			f2fs_put_page(page, 1);
105 			continue;
106 		}
107 		page_cache_release(page);
108 	}
109 }
110 
111 static struct nat_entry *__lookup_nat_cache(struct f2fs_nm_info *nm_i, nid_t n)
112 {
113 	return radix_tree_lookup(&nm_i->nat_root, n);
114 }
115 
116 static unsigned int __gang_lookup_nat_cache(struct f2fs_nm_info *nm_i,
117 		nid_t start, unsigned int nr, struct nat_entry **ep)
118 {
119 	return radix_tree_gang_lookup(&nm_i->nat_root, (void **)ep, start, nr);
120 }
121 
122 static void __del_from_nat_cache(struct f2fs_nm_info *nm_i, struct nat_entry *e)
123 {
124 	list_del(&e->list);
125 	radix_tree_delete(&nm_i->nat_root, nat_get_nid(e));
126 	nm_i->nat_cnt--;
127 	kmem_cache_free(nat_entry_slab, e);
128 }
129 
130 int is_checkpointed_node(struct f2fs_sb_info *sbi, nid_t nid)
131 {
132 	struct f2fs_nm_info *nm_i = NM_I(sbi);
133 	struct nat_entry *e;
134 	int is_cp = 1;
135 
136 	read_lock(&nm_i->nat_tree_lock);
137 	e = __lookup_nat_cache(nm_i, nid);
138 	if (e && !e->checkpointed)
139 		is_cp = 0;
140 	read_unlock(&nm_i->nat_tree_lock);
141 	return is_cp;
142 }
143 
144 static struct nat_entry *grab_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid)
145 {
146 	struct nat_entry *new;
147 
148 	new = kmem_cache_alloc(nat_entry_slab, GFP_ATOMIC);
149 	if (!new)
150 		return NULL;
151 	if (radix_tree_insert(&nm_i->nat_root, nid, new)) {
152 		kmem_cache_free(nat_entry_slab, new);
153 		return NULL;
154 	}
155 	memset(new, 0, sizeof(struct nat_entry));
156 	nat_set_nid(new, nid);
157 	list_add_tail(&new->list, &nm_i->nat_entries);
158 	nm_i->nat_cnt++;
159 	return new;
160 }
161 
162 static void cache_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid,
163 						struct f2fs_nat_entry *ne)
164 {
165 	struct nat_entry *e;
166 retry:
167 	write_lock(&nm_i->nat_tree_lock);
168 	e = __lookup_nat_cache(nm_i, nid);
169 	if (!e) {
170 		e = grab_nat_entry(nm_i, nid);
171 		if (!e) {
172 			write_unlock(&nm_i->nat_tree_lock);
173 			goto retry;
174 		}
175 		nat_set_blkaddr(e, le32_to_cpu(ne->block_addr));
176 		nat_set_ino(e, le32_to_cpu(ne->ino));
177 		nat_set_version(e, ne->version);
178 		e->checkpointed = true;
179 	}
180 	write_unlock(&nm_i->nat_tree_lock);
181 }
182 
183 static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
184 			block_t new_blkaddr)
185 {
186 	struct f2fs_nm_info *nm_i = NM_I(sbi);
187 	struct nat_entry *e;
188 retry:
189 	write_lock(&nm_i->nat_tree_lock);
190 	e = __lookup_nat_cache(nm_i, ni->nid);
191 	if (!e) {
192 		e = grab_nat_entry(nm_i, ni->nid);
193 		if (!e) {
194 			write_unlock(&nm_i->nat_tree_lock);
195 			goto retry;
196 		}
197 		e->ni = *ni;
198 		e->checkpointed = true;
199 		BUG_ON(ni->blk_addr == NEW_ADDR);
200 	} else if (new_blkaddr == NEW_ADDR) {
201 		/*
202 		 * when nid is reallocated,
203 		 * previous nat entry can be remained in nat cache.
204 		 * So, reinitialize it with new information.
205 		 */
206 		e->ni = *ni;
207 		BUG_ON(ni->blk_addr != NULL_ADDR);
208 	}
209 
210 	if (new_blkaddr == NEW_ADDR)
211 		e->checkpointed = false;
212 
213 	/* sanity check */
214 	BUG_ON(nat_get_blkaddr(e) != ni->blk_addr);
215 	BUG_ON(nat_get_blkaddr(e) == NULL_ADDR &&
216 			new_blkaddr == NULL_ADDR);
217 	BUG_ON(nat_get_blkaddr(e) == NEW_ADDR &&
218 			new_blkaddr == NEW_ADDR);
219 	BUG_ON(nat_get_blkaddr(e) != NEW_ADDR &&
220 			nat_get_blkaddr(e) != NULL_ADDR &&
221 			new_blkaddr == NEW_ADDR);
222 
223 	/* increament version no as node is removed */
224 	if (nat_get_blkaddr(e) != NEW_ADDR && new_blkaddr == NULL_ADDR) {
225 		unsigned char version = nat_get_version(e);
226 		nat_set_version(e, inc_node_version(version));
227 	}
228 
229 	/* change address */
230 	nat_set_blkaddr(e, new_blkaddr);
231 	__set_nat_cache_dirty(nm_i, e);
232 	write_unlock(&nm_i->nat_tree_lock);
233 }
234 
235 static int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
236 {
237 	struct f2fs_nm_info *nm_i = NM_I(sbi);
238 
239 	if (nm_i->nat_cnt < 2 * NM_WOUT_THRESHOLD)
240 		return 0;
241 
242 	write_lock(&nm_i->nat_tree_lock);
243 	while (nr_shrink && !list_empty(&nm_i->nat_entries)) {
244 		struct nat_entry *ne;
245 		ne = list_first_entry(&nm_i->nat_entries,
246 					struct nat_entry, list);
247 		__del_from_nat_cache(nm_i, ne);
248 		nr_shrink--;
249 	}
250 	write_unlock(&nm_i->nat_tree_lock);
251 	return nr_shrink;
252 }
253 
254 /*
255  * This function returns always success
256  */
257 void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni)
258 {
259 	struct f2fs_nm_info *nm_i = NM_I(sbi);
260 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
261 	struct f2fs_summary_block *sum = curseg->sum_blk;
262 	nid_t start_nid = START_NID(nid);
263 	struct f2fs_nat_block *nat_blk;
264 	struct page *page = NULL;
265 	struct f2fs_nat_entry ne;
266 	struct nat_entry *e;
267 	int i;
268 
269 	ni->nid = nid;
270 
271 	/* Check nat cache */
272 	read_lock(&nm_i->nat_tree_lock);
273 	e = __lookup_nat_cache(nm_i, nid);
274 	if (e) {
275 		ni->ino = nat_get_ino(e);
276 		ni->blk_addr = nat_get_blkaddr(e);
277 		ni->version = nat_get_version(e);
278 	}
279 	read_unlock(&nm_i->nat_tree_lock);
280 	if (e)
281 		return;
282 
283 	/* Check current segment summary */
284 	mutex_lock(&curseg->curseg_mutex);
285 	i = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 0);
286 	if (i >= 0) {
287 		ne = nat_in_journal(sum, i);
288 		node_info_from_raw_nat(ni, &ne);
289 	}
290 	mutex_unlock(&curseg->curseg_mutex);
291 	if (i >= 0)
292 		goto cache;
293 
294 	/* Fill node_info from nat page */
295 	page = get_current_nat_page(sbi, start_nid);
296 	nat_blk = (struct f2fs_nat_block *)page_address(page);
297 	ne = nat_blk->entries[nid - start_nid];
298 	node_info_from_raw_nat(ni, &ne);
299 	f2fs_put_page(page, 1);
300 cache:
301 	/* cache nat entry */
302 	cache_nat_entry(NM_I(sbi), nid, &ne);
303 }
304 
305 /*
306  * The maximum depth is four.
307  * Offset[0] will have raw inode offset.
308  */
309 static int get_node_path(long block, int offset[4], unsigned int noffset[4])
310 {
311 	const long direct_index = ADDRS_PER_INODE;
312 	const long direct_blks = ADDRS_PER_BLOCK;
313 	const long dptrs_per_blk = NIDS_PER_BLOCK;
314 	const long indirect_blks = ADDRS_PER_BLOCK * NIDS_PER_BLOCK;
315 	const long dindirect_blks = indirect_blks * NIDS_PER_BLOCK;
316 	int n = 0;
317 	int level = 0;
318 
319 	noffset[0] = 0;
320 
321 	if (block < direct_index) {
322 		offset[n++] = block;
323 		level = 0;
324 		goto got;
325 	}
326 	block -= direct_index;
327 	if (block < direct_blks) {
328 		offset[n++] = NODE_DIR1_BLOCK;
329 		noffset[n] = 1;
330 		offset[n++] = block;
331 		level = 1;
332 		goto got;
333 	}
334 	block -= direct_blks;
335 	if (block < direct_blks) {
336 		offset[n++] = NODE_DIR2_BLOCK;
337 		noffset[n] = 2;
338 		offset[n++] = block;
339 		level = 1;
340 		goto got;
341 	}
342 	block -= direct_blks;
343 	if (block < indirect_blks) {
344 		offset[n++] = NODE_IND1_BLOCK;
345 		noffset[n] = 3;
346 		offset[n++] = block / direct_blks;
347 		noffset[n] = 4 + offset[n - 1];
348 		offset[n++] = block % direct_blks;
349 		level = 2;
350 		goto got;
351 	}
352 	block -= indirect_blks;
353 	if (block < indirect_blks) {
354 		offset[n++] = NODE_IND2_BLOCK;
355 		noffset[n] = 4 + dptrs_per_blk;
356 		offset[n++] = block / direct_blks;
357 		noffset[n] = 5 + dptrs_per_blk + offset[n - 1];
358 		offset[n++] = block % direct_blks;
359 		level = 2;
360 		goto got;
361 	}
362 	block -= indirect_blks;
363 	if (block < dindirect_blks) {
364 		offset[n++] = NODE_DIND_BLOCK;
365 		noffset[n] = 5 + (dptrs_per_blk * 2);
366 		offset[n++] = block / indirect_blks;
367 		noffset[n] = 6 + (dptrs_per_blk * 2) +
368 			      offset[n - 1] * (dptrs_per_blk + 1);
369 		offset[n++] = (block / direct_blks) % dptrs_per_blk;
370 		noffset[n] = 7 + (dptrs_per_blk * 2) +
371 			      offset[n - 2] * (dptrs_per_blk + 1) +
372 			      offset[n - 1];
373 		offset[n++] = block % direct_blks;
374 		level = 3;
375 		goto got;
376 	} else {
377 		BUG();
378 	}
379 got:
380 	return level;
381 }
382 
383 /*
384  * Caller should call f2fs_put_dnode(dn).
385  */
386 int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int ro)
387 {
388 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
389 	struct page *npage[4];
390 	struct page *parent;
391 	int offset[4];
392 	unsigned int noffset[4];
393 	nid_t nids[4];
394 	int level, i;
395 	int err = 0;
396 
397 	level = get_node_path(index, offset, noffset);
398 
399 	nids[0] = dn->inode->i_ino;
400 	npage[0] = get_node_page(sbi, nids[0]);
401 	if (IS_ERR(npage[0]))
402 		return PTR_ERR(npage[0]);
403 
404 	parent = npage[0];
405 	nids[1] = get_nid(parent, offset[0], true);
406 	dn->inode_page = npage[0];
407 	dn->inode_page_locked = true;
408 
409 	/* get indirect or direct nodes */
410 	for (i = 1; i <= level; i++) {
411 		bool done = false;
412 
413 		if (!nids[i] && !ro) {
414 			mutex_lock_op(sbi, NODE_NEW);
415 
416 			/* alloc new node */
417 			if (!alloc_nid(sbi, &(nids[i]))) {
418 				mutex_unlock_op(sbi, NODE_NEW);
419 				err = -ENOSPC;
420 				goto release_pages;
421 			}
422 
423 			dn->nid = nids[i];
424 			npage[i] = new_node_page(dn, noffset[i]);
425 			if (IS_ERR(npage[i])) {
426 				alloc_nid_failed(sbi, nids[i]);
427 				mutex_unlock_op(sbi, NODE_NEW);
428 				err = PTR_ERR(npage[i]);
429 				goto release_pages;
430 			}
431 
432 			set_nid(parent, offset[i - 1], nids[i], i == 1);
433 			alloc_nid_done(sbi, nids[i]);
434 			mutex_unlock_op(sbi, NODE_NEW);
435 			done = true;
436 		} else if (ro && i == level && level > 1) {
437 			npage[i] = get_node_page_ra(parent, offset[i - 1]);
438 			if (IS_ERR(npage[i])) {
439 				err = PTR_ERR(npage[i]);
440 				goto release_pages;
441 			}
442 			done = true;
443 		}
444 		if (i == 1) {
445 			dn->inode_page_locked = false;
446 			unlock_page(parent);
447 		} else {
448 			f2fs_put_page(parent, 1);
449 		}
450 
451 		if (!done) {
452 			npage[i] = get_node_page(sbi, nids[i]);
453 			if (IS_ERR(npage[i])) {
454 				err = PTR_ERR(npage[i]);
455 				f2fs_put_page(npage[0], 0);
456 				goto release_out;
457 			}
458 		}
459 		if (i < level) {
460 			parent = npage[i];
461 			nids[i + 1] = get_nid(parent, offset[i], false);
462 		}
463 	}
464 	dn->nid = nids[level];
465 	dn->ofs_in_node = offset[level];
466 	dn->node_page = npage[level];
467 	dn->data_blkaddr = datablock_addr(dn->node_page, dn->ofs_in_node);
468 	return 0;
469 
470 release_pages:
471 	f2fs_put_page(parent, 1);
472 	if (i > 1)
473 		f2fs_put_page(npage[0], 0);
474 release_out:
475 	dn->inode_page = NULL;
476 	dn->node_page = NULL;
477 	return err;
478 }
479 
480 static void truncate_node(struct dnode_of_data *dn)
481 {
482 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
483 	struct node_info ni;
484 
485 	get_node_info(sbi, dn->nid, &ni);
486 	BUG_ON(ni.blk_addr == NULL_ADDR);
487 
488 	if (ni.blk_addr != NULL_ADDR)
489 		invalidate_blocks(sbi, ni.blk_addr);
490 
491 	/* Deallocate node address */
492 	dec_valid_node_count(sbi, dn->inode, 1);
493 	set_node_addr(sbi, &ni, NULL_ADDR);
494 
495 	if (dn->nid == dn->inode->i_ino) {
496 		remove_orphan_inode(sbi, dn->nid);
497 		dec_valid_inode_count(sbi);
498 	} else {
499 		sync_inode_page(dn);
500 	}
501 
502 	clear_node_page_dirty(dn->node_page);
503 	F2FS_SET_SB_DIRT(sbi);
504 
505 	f2fs_put_page(dn->node_page, 1);
506 	dn->node_page = NULL;
507 }
508 
509 static int truncate_dnode(struct dnode_of_data *dn)
510 {
511 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
512 	struct page *page;
513 
514 	if (dn->nid == 0)
515 		return 1;
516 
517 	/* get direct node */
518 	page = get_node_page(sbi, dn->nid);
519 	if (IS_ERR(page) && PTR_ERR(page) == -ENOENT)
520 		return 1;
521 	else if (IS_ERR(page))
522 		return PTR_ERR(page);
523 
524 	/* Make dnode_of_data for parameter */
525 	dn->node_page = page;
526 	dn->ofs_in_node = 0;
527 	truncate_data_blocks(dn);
528 	truncate_node(dn);
529 	return 1;
530 }
531 
532 static int truncate_nodes(struct dnode_of_data *dn, unsigned int nofs,
533 						int ofs, int depth)
534 {
535 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
536 	struct dnode_of_data rdn = *dn;
537 	struct page *page;
538 	struct f2fs_node *rn;
539 	nid_t child_nid;
540 	unsigned int child_nofs;
541 	int freed = 0;
542 	int i, ret;
543 
544 	if (dn->nid == 0)
545 		return NIDS_PER_BLOCK + 1;
546 
547 	page = get_node_page(sbi, dn->nid);
548 	if (IS_ERR(page))
549 		return PTR_ERR(page);
550 
551 	rn = (struct f2fs_node *)page_address(page);
552 	if (depth < 3) {
553 		for (i = ofs; i < NIDS_PER_BLOCK; i++, freed++) {
554 			child_nid = le32_to_cpu(rn->in.nid[i]);
555 			if (child_nid == 0)
556 				continue;
557 			rdn.nid = child_nid;
558 			ret = truncate_dnode(&rdn);
559 			if (ret < 0)
560 				goto out_err;
561 			set_nid(page, i, 0, false);
562 		}
563 	} else {
564 		child_nofs = nofs + ofs * (NIDS_PER_BLOCK + 1) + 1;
565 		for (i = ofs; i < NIDS_PER_BLOCK; i++) {
566 			child_nid = le32_to_cpu(rn->in.nid[i]);
567 			if (child_nid == 0) {
568 				child_nofs += NIDS_PER_BLOCK + 1;
569 				continue;
570 			}
571 			rdn.nid = child_nid;
572 			ret = truncate_nodes(&rdn, child_nofs, 0, depth - 1);
573 			if (ret == (NIDS_PER_BLOCK + 1)) {
574 				set_nid(page, i, 0, false);
575 				child_nofs += ret;
576 			} else if (ret < 0 && ret != -ENOENT) {
577 				goto out_err;
578 			}
579 		}
580 		freed = child_nofs;
581 	}
582 
583 	if (!ofs) {
584 		/* remove current indirect node */
585 		dn->node_page = page;
586 		truncate_node(dn);
587 		freed++;
588 	} else {
589 		f2fs_put_page(page, 1);
590 	}
591 	return freed;
592 
593 out_err:
594 	f2fs_put_page(page, 1);
595 	return ret;
596 }
597 
598 static int truncate_partial_nodes(struct dnode_of_data *dn,
599 			struct f2fs_inode *ri, int *offset, int depth)
600 {
601 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
602 	struct page *pages[2];
603 	nid_t nid[3];
604 	nid_t child_nid;
605 	int err = 0;
606 	int i;
607 	int idx = depth - 2;
608 
609 	nid[0] = le32_to_cpu(ri->i_nid[offset[0] - NODE_DIR1_BLOCK]);
610 	if (!nid[0])
611 		return 0;
612 
613 	/* get indirect nodes in the path */
614 	for (i = 0; i < depth - 1; i++) {
615 		/* refernece count'll be increased */
616 		pages[i] = get_node_page(sbi, nid[i]);
617 		if (IS_ERR(pages[i])) {
618 			depth = i + 1;
619 			err = PTR_ERR(pages[i]);
620 			goto fail;
621 		}
622 		nid[i + 1] = get_nid(pages[i], offset[i + 1], false);
623 	}
624 
625 	/* free direct nodes linked to a partial indirect node */
626 	for (i = offset[depth - 1]; i < NIDS_PER_BLOCK; i++) {
627 		child_nid = get_nid(pages[idx], i, false);
628 		if (!child_nid)
629 			continue;
630 		dn->nid = child_nid;
631 		err = truncate_dnode(dn);
632 		if (err < 0)
633 			goto fail;
634 		set_nid(pages[idx], i, 0, false);
635 	}
636 
637 	if (offset[depth - 1] == 0) {
638 		dn->node_page = pages[idx];
639 		dn->nid = nid[idx];
640 		truncate_node(dn);
641 	} else {
642 		f2fs_put_page(pages[idx], 1);
643 	}
644 	offset[idx]++;
645 	offset[depth - 1] = 0;
646 fail:
647 	for (i = depth - 3; i >= 0; i--)
648 		f2fs_put_page(pages[i], 1);
649 	return err;
650 }
651 
652 /*
653  * All the block addresses of data and nodes should be nullified.
654  */
655 int truncate_inode_blocks(struct inode *inode, pgoff_t from)
656 {
657 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
658 	int err = 0, cont = 1;
659 	int level, offset[4], noffset[4];
660 	unsigned int nofs;
661 	struct f2fs_node *rn;
662 	struct dnode_of_data dn;
663 	struct page *page;
664 
665 	level = get_node_path(from, offset, noffset);
666 
667 	page = get_node_page(sbi, inode->i_ino);
668 	if (IS_ERR(page))
669 		return PTR_ERR(page);
670 
671 	set_new_dnode(&dn, inode, page, NULL, 0);
672 	unlock_page(page);
673 
674 	rn = page_address(page);
675 	switch (level) {
676 	case 0:
677 	case 1:
678 		nofs = noffset[1];
679 		break;
680 	case 2:
681 		nofs = noffset[1];
682 		if (!offset[level - 1])
683 			goto skip_partial;
684 		err = truncate_partial_nodes(&dn, &rn->i, offset, level);
685 		if (err < 0 && err != -ENOENT)
686 			goto fail;
687 		nofs += 1 + NIDS_PER_BLOCK;
688 		break;
689 	case 3:
690 		nofs = 5 + 2 * NIDS_PER_BLOCK;
691 		if (!offset[level - 1])
692 			goto skip_partial;
693 		err = truncate_partial_nodes(&dn, &rn->i, offset, level);
694 		if (err < 0 && err != -ENOENT)
695 			goto fail;
696 		break;
697 	default:
698 		BUG();
699 	}
700 
701 skip_partial:
702 	while (cont) {
703 		dn.nid = le32_to_cpu(rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK]);
704 		switch (offset[0]) {
705 		case NODE_DIR1_BLOCK:
706 		case NODE_DIR2_BLOCK:
707 			err = truncate_dnode(&dn);
708 			break;
709 
710 		case NODE_IND1_BLOCK:
711 		case NODE_IND2_BLOCK:
712 			err = truncate_nodes(&dn, nofs, offset[1], 2);
713 			break;
714 
715 		case NODE_DIND_BLOCK:
716 			err = truncate_nodes(&dn, nofs, offset[1], 3);
717 			cont = 0;
718 			break;
719 
720 		default:
721 			BUG();
722 		}
723 		if (err < 0 && err != -ENOENT)
724 			goto fail;
725 		if (offset[1] == 0 &&
726 				rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK]) {
727 			lock_page(page);
728 			wait_on_page_writeback(page);
729 			rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK] = 0;
730 			set_page_dirty(page);
731 			unlock_page(page);
732 		}
733 		offset[1] = 0;
734 		offset[0]++;
735 		nofs += err;
736 	}
737 fail:
738 	f2fs_put_page(page, 0);
739 	return err > 0 ? 0 : err;
740 }
741 
742 int remove_inode_page(struct inode *inode)
743 {
744 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
745 	struct page *page;
746 	nid_t ino = inode->i_ino;
747 	struct dnode_of_data dn;
748 
749 	mutex_lock_op(sbi, NODE_TRUNC);
750 	page = get_node_page(sbi, ino);
751 	if (IS_ERR(page)) {
752 		mutex_unlock_op(sbi, NODE_TRUNC);
753 		return PTR_ERR(page);
754 	}
755 
756 	if (F2FS_I(inode)->i_xattr_nid) {
757 		nid_t nid = F2FS_I(inode)->i_xattr_nid;
758 		struct page *npage = get_node_page(sbi, nid);
759 
760 		if (IS_ERR(npage)) {
761 			mutex_unlock_op(sbi, NODE_TRUNC);
762 			return PTR_ERR(npage);
763 		}
764 
765 		F2FS_I(inode)->i_xattr_nid = 0;
766 		set_new_dnode(&dn, inode, page, npage, nid);
767 		dn.inode_page_locked = 1;
768 		truncate_node(&dn);
769 	}
770 	if (inode->i_blocks == 1) {
771 		/* inernally call f2fs_put_page() */
772 		set_new_dnode(&dn, inode, page, page, ino);
773 		truncate_node(&dn);
774 	} else if (inode->i_blocks == 0) {
775 		struct node_info ni;
776 		get_node_info(sbi, inode->i_ino, &ni);
777 
778 		/* called after f2fs_new_inode() is failed */
779 		BUG_ON(ni.blk_addr != NULL_ADDR);
780 		f2fs_put_page(page, 1);
781 	} else {
782 		BUG();
783 	}
784 	mutex_unlock_op(sbi, NODE_TRUNC);
785 	return 0;
786 }
787 
788 int new_inode_page(struct inode *inode, struct dentry *dentry)
789 {
790 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
791 	struct page *page;
792 	struct dnode_of_data dn;
793 
794 	/* allocate inode page for new inode */
795 	set_new_dnode(&dn, inode, NULL, NULL, inode->i_ino);
796 	mutex_lock_op(sbi, NODE_NEW);
797 	page = new_node_page(&dn, 0);
798 	init_dent_inode(dentry, page);
799 	mutex_unlock_op(sbi, NODE_NEW);
800 	if (IS_ERR(page))
801 		return PTR_ERR(page);
802 	f2fs_put_page(page, 1);
803 	return 0;
804 }
805 
806 struct page *new_node_page(struct dnode_of_data *dn, unsigned int ofs)
807 {
808 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
809 	struct address_space *mapping = sbi->node_inode->i_mapping;
810 	struct node_info old_ni, new_ni;
811 	struct page *page;
812 	int err;
813 
814 	if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
815 		return ERR_PTR(-EPERM);
816 
817 	page = grab_cache_page(mapping, dn->nid);
818 	if (!page)
819 		return ERR_PTR(-ENOMEM);
820 
821 	get_node_info(sbi, dn->nid, &old_ni);
822 
823 	SetPageUptodate(page);
824 	fill_node_footer(page, dn->nid, dn->inode->i_ino, ofs, true);
825 
826 	/* Reinitialize old_ni with new node page */
827 	BUG_ON(old_ni.blk_addr != NULL_ADDR);
828 	new_ni = old_ni;
829 	new_ni.ino = dn->inode->i_ino;
830 
831 	if (!inc_valid_node_count(sbi, dn->inode, 1)) {
832 		err = -ENOSPC;
833 		goto fail;
834 	}
835 	set_node_addr(sbi, &new_ni, NEW_ADDR);
836 
837 	dn->node_page = page;
838 	sync_inode_page(dn);
839 	set_page_dirty(page);
840 	set_cold_node(dn->inode, page);
841 	if (ofs == 0)
842 		inc_valid_inode_count(sbi);
843 
844 	return page;
845 
846 fail:
847 	f2fs_put_page(page, 1);
848 	return ERR_PTR(err);
849 }
850 
851 static int read_node_page(struct page *page, int type)
852 {
853 	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
854 	struct node_info ni;
855 
856 	get_node_info(sbi, page->index, &ni);
857 
858 	if (ni.blk_addr == NULL_ADDR)
859 		return -ENOENT;
860 	return f2fs_readpage(sbi, page, ni.blk_addr, type);
861 }
862 
863 /*
864  * Readahead a node page
865  */
866 void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
867 {
868 	struct address_space *mapping = sbi->node_inode->i_mapping;
869 	struct page *apage;
870 
871 	apage = find_get_page(mapping, nid);
872 	if (apage && PageUptodate(apage))
873 		goto release_out;
874 	f2fs_put_page(apage, 0);
875 
876 	apage = grab_cache_page(mapping, nid);
877 	if (!apage)
878 		return;
879 
880 	if (read_node_page(apage, READA))
881 		goto unlock_out;
882 
883 	page_cache_release(apage);
884 	return;
885 
886 unlock_out:
887 	unlock_page(apage);
888 release_out:
889 	page_cache_release(apage);
890 }
891 
892 struct page *get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid)
893 {
894 	int err;
895 	struct page *page;
896 	struct address_space *mapping = sbi->node_inode->i_mapping;
897 
898 	page = grab_cache_page(mapping, nid);
899 	if (!page)
900 		return ERR_PTR(-ENOMEM);
901 
902 	err = read_node_page(page, READ_SYNC);
903 	if (err) {
904 		f2fs_put_page(page, 1);
905 		return ERR_PTR(err);
906 	}
907 
908 	BUG_ON(nid != nid_of_node(page));
909 	mark_page_accessed(page);
910 	return page;
911 }
912 
913 /*
914  * Return a locked page for the desired node page.
915  * And, readahead MAX_RA_NODE number of node pages.
916  */
917 struct page *get_node_page_ra(struct page *parent, int start)
918 {
919 	struct f2fs_sb_info *sbi = F2FS_SB(parent->mapping->host->i_sb);
920 	struct address_space *mapping = sbi->node_inode->i_mapping;
921 	int i, end;
922 	int err = 0;
923 	nid_t nid;
924 	struct page *page;
925 
926 	/* First, try getting the desired direct node. */
927 	nid = get_nid(parent, start, false);
928 	if (!nid)
929 		return ERR_PTR(-ENOENT);
930 
931 	page = find_get_page(mapping, nid);
932 	if (page && PageUptodate(page))
933 		goto page_hit;
934 	f2fs_put_page(page, 0);
935 
936 repeat:
937 	page = grab_cache_page(mapping, nid);
938 	if (!page)
939 		return ERR_PTR(-ENOMEM);
940 
941 	err = read_node_page(page, READA);
942 	if (err) {
943 		f2fs_put_page(page, 1);
944 		return ERR_PTR(err);
945 	}
946 
947 	/* Then, try readahead for siblings of the desired node */
948 	end = start + MAX_RA_NODE;
949 	end = min(end, NIDS_PER_BLOCK);
950 	for (i = start + 1; i < end; i++) {
951 		nid = get_nid(parent, i, false);
952 		if (!nid)
953 			continue;
954 		ra_node_page(sbi, nid);
955 	}
956 
957 page_hit:
958 	lock_page(page);
959 	if (PageError(page)) {
960 		f2fs_put_page(page, 1);
961 		return ERR_PTR(-EIO);
962 	}
963 
964 	/* Has the page been truncated? */
965 	if (page->mapping != mapping) {
966 		f2fs_put_page(page, 1);
967 		goto repeat;
968 	}
969 	return page;
970 }
971 
972 void sync_inode_page(struct dnode_of_data *dn)
973 {
974 	if (IS_INODE(dn->node_page) || dn->inode_page == dn->node_page) {
975 		update_inode(dn->inode, dn->node_page);
976 	} else if (dn->inode_page) {
977 		if (!dn->inode_page_locked)
978 			lock_page(dn->inode_page);
979 		update_inode(dn->inode, dn->inode_page);
980 		if (!dn->inode_page_locked)
981 			unlock_page(dn->inode_page);
982 	} else {
983 		f2fs_write_inode(dn->inode, NULL);
984 	}
985 }
986 
987 int sync_node_pages(struct f2fs_sb_info *sbi, nid_t ino,
988 					struct writeback_control *wbc)
989 {
990 	struct address_space *mapping = sbi->node_inode->i_mapping;
991 	pgoff_t index, end;
992 	struct pagevec pvec;
993 	int step = ino ? 2 : 0;
994 	int nwritten = 0, wrote = 0;
995 
996 	pagevec_init(&pvec, 0);
997 
998 next_step:
999 	index = 0;
1000 	end = LONG_MAX;
1001 
1002 	while (index <= end) {
1003 		int i, nr_pages;
1004 		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
1005 				PAGECACHE_TAG_DIRTY,
1006 				min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
1007 		if (nr_pages == 0)
1008 			break;
1009 
1010 		for (i = 0; i < nr_pages; i++) {
1011 			struct page *page = pvec.pages[i];
1012 
1013 			/*
1014 			 * flushing sequence with step:
1015 			 * 0. indirect nodes
1016 			 * 1. dentry dnodes
1017 			 * 2. file dnodes
1018 			 */
1019 			if (step == 0 && IS_DNODE(page))
1020 				continue;
1021 			if (step == 1 && (!IS_DNODE(page) ||
1022 						is_cold_node(page)))
1023 				continue;
1024 			if (step == 2 && (!IS_DNODE(page) ||
1025 						!is_cold_node(page)))
1026 				continue;
1027 
1028 			/*
1029 			 * If an fsync mode,
1030 			 * we should not skip writing node pages.
1031 			 */
1032 			if (ino && ino_of_node(page) == ino)
1033 				lock_page(page);
1034 			else if (!trylock_page(page))
1035 				continue;
1036 
1037 			if (unlikely(page->mapping != mapping)) {
1038 continue_unlock:
1039 				unlock_page(page);
1040 				continue;
1041 			}
1042 			if (ino && ino_of_node(page) != ino)
1043 				goto continue_unlock;
1044 
1045 			if (!PageDirty(page)) {
1046 				/* someone wrote it for us */
1047 				goto continue_unlock;
1048 			}
1049 
1050 			if (!clear_page_dirty_for_io(page))
1051 				goto continue_unlock;
1052 
1053 			/* called by fsync() */
1054 			if (ino && IS_DNODE(page)) {
1055 				int mark = !is_checkpointed_node(sbi, ino);
1056 				set_fsync_mark(page, 1);
1057 				if (IS_INODE(page))
1058 					set_dentry_mark(page, mark);
1059 				nwritten++;
1060 			} else {
1061 				set_fsync_mark(page, 0);
1062 				set_dentry_mark(page, 0);
1063 			}
1064 			mapping->a_ops->writepage(page, wbc);
1065 			wrote++;
1066 
1067 			if (--wbc->nr_to_write == 0)
1068 				break;
1069 		}
1070 		pagevec_release(&pvec);
1071 		cond_resched();
1072 
1073 		if (wbc->nr_to_write == 0) {
1074 			step = 2;
1075 			break;
1076 		}
1077 	}
1078 
1079 	if (step < 2) {
1080 		step++;
1081 		goto next_step;
1082 	}
1083 
1084 	if (wrote)
1085 		f2fs_submit_bio(sbi, NODE, wbc->sync_mode == WB_SYNC_ALL);
1086 
1087 	return nwritten;
1088 }
1089 
1090 static int f2fs_write_node_page(struct page *page,
1091 				struct writeback_control *wbc)
1092 {
1093 	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
1094 	nid_t nid;
1095 	unsigned int nofs;
1096 	block_t new_addr;
1097 	struct node_info ni;
1098 
1099 	if (wbc->for_reclaim) {
1100 		dec_page_count(sbi, F2FS_DIRTY_NODES);
1101 		wbc->pages_skipped++;
1102 		set_page_dirty(page);
1103 		return AOP_WRITEPAGE_ACTIVATE;
1104 	}
1105 
1106 	wait_on_page_writeback(page);
1107 
1108 	mutex_lock_op(sbi, NODE_WRITE);
1109 
1110 	/* get old block addr of this node page */
1111 	nid = nid_of_node(page);
1112 	nofs = ofs_of_node(page);
1113 	BUG_ON(page->index != nid);
1114 
1115 	get_node_info(sbi, nid, &ni);
1116 
1117 	/* This page is already truncated */
1118 	if (ni.blk_addr == NULL_ADDR)
1119 		return 0;
1120 
1121 	set_page_writeback(page);
1122 
1123 	/* insert node offset */
1124 	write_node_page(sbi, page, nid, ni.blk_addr, &new_addr);
1125 	set_node_addr(sbi, &ni, new_addr);
1126 	dec_page_count(sbi, F2FS_DIRTY_NODES);
1127 
1128 	mutex_unlock_op(sbi, NODE_WRITE);
1129 	unlock_page(page);
1130 	return 0;
1131 }
1132 
1133 static int f2fs_write_node_pages(struct address_space *mapping,
1134 			    struct writeback_control *wbc)
1135 {
1136 	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1137 	struct block_device *bdev = sbi->sb->s_bdev;
1138 	long nr_to_write = wbc->nr_to_write;
1139 
1140 	if (wbc->for_kupdate)
1141 		return 0;
1142 
1143 	if (get_pages(sbi, F2FS_DIRTY_NODES) == 0)
1144 		return 0;
1145 
1146 	if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) {
1147 		write_checkpoint(sbi, false, false);
1148 		return 0;
1149 	}
1150 
1151 	/* if mounting is failed, skip writing node pages */
1152 	wbc->nr_to_write = bio_get_nr_vecs(bdev);
1153 	sync_node_pages(sbi, 0, wbc);
1154 	wbc->nr_to_write = nr_to_write -
1155 		(bio_get_nr_vecs(bdev) - wbc->nr_to_write);
1156 	return 0;
1157 }
1158 
1159 static int f2fs_set_node_page_dirty(struct page *page)
1160 {
1161 	struct address_space *mapping = page->mapping;
1162 	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1163 
1164 	SetPageUptodate(page);
1165 	if (!PageDirty(page)) {
1166 		__set_page_dirty_nobuffers(page);
1167 		inc_page_count(sbi, F2FS_DIRTY_NODES);
1168 		SetPagePrivate(page);
1169 		return 1;
1170 	}
1171 	return 0;
1172 }
1173 
1174 static void f2fs_invalidate_node_page(struct page *page, unsigned long offset)
1175 {
1176 	struct inode *inode = page->mapping->host;
1177 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
1178 	if (PageDirty(page))
1179 		dec_page_count(sbi, F2FS_DIRTY_NODES);
1180 	ClearPagePrivate(page);
1181 }
1182 
1183 static int f2fs_release_node_page(struct page *page, gfp_t wait)
1184 {
1185 	ClearPagePrivate(page);
1186 	return 0;
1187 }
1188 
1189 /*
1190  * Structure of the f2fs node operations
1191  */
1192 const struct address_space_operations f2fs_node_aops = {
1193 	.writepage	= f2fs_write_node_page,
1194 	.writepages	= f2fs_write_node_pages,
1195 	.set_page_dirty	= f2fs_set_node_page_dirty,
1196 	.invalidatepage	= f2fs_invalidate_node_page,
1197 	.releasepage	= f2fs_release_node_page,
1198 };
1199 
1200 static struct free_nid *__lookup_free_nid_list(nid_t n, struct list_head *head)
1201 {
1202 	struct list_head *this;
1203 	struct free_nid *i = NULL;
1204 	list_for_each(this, head) {
1205 		i = list_entry(this, struct free_nid, list);
1206 		if (i->nid == n)
1207 			break;
1208 		i = NULL;
1209 	}
1210 	return i;
1211 }
1212 
1213 static void __del_from_free_nid_list(struct free_nid *i)
1214 {
1215 	list_del(&i->list);
1216 	kmem_cache_free(free_nid_slab, i);
1217 }
1218 
1219 static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
1220 {
1221 	struct free_nid *i;
1222 
1223 	if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
1224 		return 0;
1225 retry:
1226 	i = kmem_cache_alloc(free_nid_slab, GFP_NOFS);
1227 	if (!i) {
1228 		cond_resched();
1229 		goto retry;
1230 	}
1231 	i->nid = nid;
1232 	i->state = NID_NEW;
1233 
1234 	spin_lock(&nm_i->free_nid_list_lock);
1235 	if (__lookup_free_nid_list(nid, &nm_i->free_nid_list)) {
1236 		spin_unlock(&nm_i->free_nid_list_lock);
1237 		kmem_cache_free(free_nid_slab, i);
1238 		return 0;
1239 	}
1240 	list_add_tail(&i->list, &nm_i->free_nid_list);
1241 	nm_i->fcnt++;
1242 	spin_unlock(&nm_i->free_nid_list_lock);
1243 	return 1;
1244 }
1245 
1246 static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
1247 {
1248 	struct free_nid *i;
1249 	spin_lock(&nm_i->free_nid_list_lock);
1250 	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
1251 	if (i && i->state == NID_NEW) {
1252 		__del_from_free_nid_list(i);
1253 		nm_i->fcnt--;
1254 	}
1255 	spin_unlock(&nm_i->free_nid_list_lock);
1256 }
1257 
1258 static int scan_nat_page(struct f2fs_nm_info *nm_i,
1259 			struct page *nat_page, nid_t start_nid)
1260 {
1261 	struct f2fs_nat_block *nat_blk = page_address(nat_page);
1262 	block_t blk_addr;
1263 	int fcnt = 0;
1264 	int i;
1265 
1266 	/* 0 nid should not be used */
1267 	if (start_nid == 0)
1268 		++start_nid;
1269 
1270 	i = start_nid % NAT_ENTRY_PER_BLOCK;
1271 
1272 	for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
1273 		blk_addr  = le32_to_cpu(nat_blk->entries[i].block_addr);
1274 		BUG_ON(blk_addr == NEW_ADDR);
1275 		if (blk_addr == NULL_ADDR)
1276 			fcnt += add_free_nid(nm_i, start_nid);
1277 	}
1278 	return fcnt;
1279 }
1280 
1281 static void build_free_nids(struct f2fs_sb_info *sbi)
1282 {
1283 	struct free_nid *fnid, *next_fnid;
1284 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1285 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1286 	struct f2fs_summary_block *sum = curseg->sum_blk;
1287 	nid_t nid = 0;
1288 	bool is_cycled = false;
1289 	int fcnt = 0;
1290 	int i;
1291 
1292 	nid = nm_i->next_scan_nid;
1293 	nm_i->init_scan_nid = nid;
1294 
1295 	ra_nat_pages(sbi, nid);
1296 
1297 	while (1) {
1298 		struct page *page = get_current_nat_page(sbi, nid);
1299 
1300 		fcnt += scan_nat_page(nm_i, page, nid);
1301 		f2fs_put_page(page, 1);
1302 
1303 		nid += (NAT_ENTRY_PER_BLOCK - (nid % NAT_ENTRY_PER_BLOCK));
1304 
1305 		if (nid >= nm_i->max_nid) {
1306 			nid = 0;
1307 			is_cycled = true;
1308 		}
1309 		if (fcnt > MAX_FREE_NIDS)
1310 			break;
1311 		if (is_cycled && nm_i->init_scan_nid <= nid)
1312 			break;
1313 	}
1314 
1315 	nm_i->next_scan_nid = nid;
1316 
1317 	/* find free nids from current sum_pages */
1318 	mutex_lock(&curseg->curseg_mutex);
1319 	for (i = 0; i < nats_in_cursum(sum); i++) {
1320 		block_t addr = le32_to_cpu(nat_in_journal(sum, i).block_addr);
1321 		nid = le32_to_cpu(nid_in_journal(sum, i));
1322 		if (addr == NULL_ADDR)
1323 			add_free_nid(nm_i, nid);
1324 		else
1325 			remove_free_nid(nm_i, nid);
1326 	}
1327 	mutex_unlock(&curseg->curseg_mutex);
1328 
1329 	/* remove the free nids from current allocated nids */
1330 	list_for_each_entry_safe(fnid, next_fnid, &nm_i->free_nid_list, list) {
1331 		struct nat_entry *ne;
1332 
1333 		read_lock(&nm_i->nat_tree_lock);
1334 		ne = __lookup_nat_cache(nm_i, fnid->nid);
1335 		if (ne && nat_get_blkaddr(ne) != NULL_ADDR)
1336 			remove_free_nid(nm_i, fnid->nid);
1337 		read_unlock(&nm_i->nat_tree_lock);
1338 	}
1339 }
1340 
1341 /*
1342  * If this function returns success, caller can obtain a new nid
1343  * from second parameter of this function.
1344  * The returned nid could be used ino as well as nid when inode is created.
1345  */
1346 bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
1347 {
1348 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1349 	struct free_nid *i = NULL;
1350 	struct list_head *this;
1351 retry:
1352 	mutex_lock(&nm_i->build_lock);
1353 	if (!nm_i->fcnt) {
1354 		/* scan NAT in order to build free nid list */
1355 		build_free_nids(sbi);
1356 		if (!nm_i->fcnt) {
1357 			mutex_unlock(&nm_i->build_lock);
1358 			return false;
1359 		}
1360 	}
1361 	mutex_unlock(&nm_i->build_lock);
1362 
1363 	/*
1364 	 * We check fcnt again since previous check is racy as
1365 	 * we didn't hold free_nid_list_lock. So other thread
1366 	 * could consume all of free nids.
1367 	 */
1368 	spin_lock(&nm_i->free_nid_list_lock);
1369 	if (!nm_i->fcnt) {
1370 		spin_unlock(&nm_i->free_nid_list_lock);
1371 		goto retry;
1372 	}
1373 
1374 	BUG_ON(list_empty(&nm_i->free_nid_list));
1375 	list_for_each(this, &nm_i->free_nid_list) {
1376 		i = list_entry(this, struct free_nid, list);
1377 		if (i->state == NID_NEW)
1378 			break;
1379 	}
1380 
1381 	BUG_ON(i->state != NID_NEW);
1382 	*nid = i->nid;
1383 	i->state = NID_ALLOC;
1384 	nm_i->fcnt--;
1385 	spin_unlock(&nm_i->free_nid_list_lock);
1386 	return true;
1387 }
1388 
1389 /*
1390  * alloc_nid() should be called prior to this function.
1391  */
1392 void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
1393 {
1394 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1395 	struct free_nid *i;
1396 
1397 	spin_lock(&nm_i->free_nid_list_lock);
1398 	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
1399 	if (i) {
1400 		BUG_ON(i->state != NID_ALLOC);
1401 		__del_from_free_nid_list(i);
1402 	}
1403 	spin_unlock(&nm_i->free_nid_list_lock);
1404 }
1405 
1406 /*
1407  * alloc_nid() should be called prior to this function.
1408  */
1409 void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
1410 {
1411 	alloc_nid_done(sbi, nid);
1412 	add_free_nid(NM_I(sbi), nid);
1413 }
1414 
1415 void recover_node_page(struct f2fs_sb_info *sbi, struct page *page,
1416 		struct f2fs_summary *sum, struct node_info *ni,
1417 		block_t new_blkaddr)
1418 {
1419 	rewrite_node_page(sbi, page, sum, ni->blk_addr, new_blkaddr);
1420 	set_node_addr(sbi, ni, new_blkaddr);
1421 	clear_node_page_dirty(page);
1422 }
1423 
1424 int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
1425 {
1426 	struct address_space *mapping = sbi->node_inode->i_mapping;
1427 	struct f2fs_node *src, *dst;
1428 	nid_t ino = ino_of_node(page);
1429 	struct node_info old_ni, new_ni;
1430 	struct page *ipage;
1431 
1432 	ipage = grab_cache_page(mapping, ino);
1433 	if (!ipage)
1434 		return -ENOMEM;
1435 
1436 	/* Should not use this inode  from free nid list */
1437 	remove_free_nid(NM_I(sbi), ino);
1438 
1439 	get_node_info(sbi, ino, &old_ni);
1440 	SetPageUptodate(ipage);
1441 	fill_node_footer(ipage, ino, ino, 0, true);
1442 
1443 	src = (struct f2fs_node *)page_address(page);
1444 	dst = (struct f2fs_node *)page_address(ipage);
1445 
1446 	memcpy(dst, src, (unsigned long)&src->i.i_ext - (unsigned long)&src->i);
1447 	dst->i.i_size = 0;
1448 	dst->i.i_blocks = cpu_to_le64(1);
1449 	dst->i.i_links = cpu_to_le32(1);
1450 	dst->i.i_xattr_nid = 0;
1451 
1452 	new_ni = old_ni;
1453 	new_ni.ino = ino;
1454 
1455 	set_node_addr(sbi, &new_ni, NEW_ADDR);
1456 	inc_valid_inode_count(sbi);
1457 
1458 	f2fs_put_page(ipage, 1);
1459 	return 0;
1460 }
1461 
1462 int restore_node_summary(struct f2fs_sb_info *sbi,
1463 			unsigned int segno, struct f2fs_summary_block *sum)
1464 {
1465 	struct f2fs_node *rn;
1466 	struct f2fs_summary *sum_entry;
1467 	struct page *page;
1468 	block_t addr;
1469 	int i, last_offset;
1470 
1471 	/* alloc temporal page for read node */
1472 	page = alloc_page(GFP_NOFS | __GFP_ZERO);
1473 	if (IS_ERR(page))
1474 		return PTR_ERR(page);
1475 	lock_page(page);
1476 
1477 	/* scan the node segment */
1478 	last_offset = sbi->blocks_per_seg;
1479 	addr = START_BLOCK(sbi, segno);
1480 	sum_entry = &sum->entries[0];
1481 
1482 	for (i = 0; i < last_offset; i++, sum_entry++) {
1483 		if (f2fs_readpage(sbi, page, addr, READ_SYNC))
1484 			goto out;
1485 
1486 		rn = (struct f2fs_node *)page_address(page);
1487 		sum_entry->nid = rn->footer.nid;
1488 		sum_entry->version = 0;
1489 		sum_entry->ofs_in_node = 0;
1490 		addr++;
1491 
1492 		/*
1493 		 * In order to read next node page,
1494 		 * we must clear PageUptodate flag.
1495 		 */
1496 		ClearPageUptodate(page);
1497 	}
1498 out:
1499 	unlock_page(page);
1500 	__free_pages(page, 0);
1501 	return 0;
1502 }
1503 
1504 static bool flush_nats_in_journal(struct f2fs_sb_info *sbi)
1505 {
1506 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1507 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1508 	struct f2fs_summary_block *sum = curseg->sum_blk;
1509 	int i;
1510 
1511 	mutex_lock(&curseg->curseg_mutex);
1512 
1513 	if (nats_in_cursum(sum) < NAT_JOURNAL_ENTRIES) {
1514 		mutex_unlock(&curseg->curseg_mutex);
1515 		return false;
1516 	}
1517 
1518 	for (i = 0; i < nats_in_cursum(sum); i++) {
1519 		struct nat_entry *ne;
1520 		struct f2fs_nat_entry raw_ne;
1521 		nid_t nid = le32_to_cpu(nid_in_journal(sum, i));
1522 
1523 		raw_ne = nat_in_journal(sum, i);
1524 retry:
1525 		write_lock(&nm_i->nat_tree_lock);
1526 		ne = __lookup_nat_cache(nm_i, nid);
1527 		if (ne) {
1528 			__set_nat_cache_dirty(nm_i, ne);
1529 			write_unlock(&nm_i->nat_tree_lock);
1530 			continue;
1531 		}
1532 		ne = grab_nat_entry(nm_i, nid);
1533 		if (!ne) {
1534 			write_unlock(&nm_i->nat_tree_lock);
1535 			goto retry;
1536 		}
1537 		nat_set_blkaddr(ne, le32_to_cpu(raw_ne.block_addr));
1538 		nat_set_ino(ne, le32_to_cpu(raw_ne.ino));
1539 		nat_set_version(ne, raw_ne.version);
1540 		__set_nat_cache_dirty(nm_i, ne);
1541 		write_unlock(&nm_i->nat_tree_lock);
1542 	}
1543 	update_nats_in_cursum(sum, -i);
1544 	mutex_unlock(&curseg->curseg_mutex);
1545 	return true;
1546 }
1547 
1548 /*
1549  * This function is called during the checkpointing process.
1550  */
1551 void flush_nat_entries(struct f2fs_sb_info *sbi)
1552 {
1553 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1554 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1555 	struct f2fs_summary_block *sum = curseg->sum_blk;
1556 	struct list_head *cur, *n;
1557 	struct page *page = NULL;
1558 	struct f2fs_nat_block *nat_blk = NULL;
1559 	nid_t start_nid = 0, end_nid = 0;
1560 	bool flushed;
1561 
1562 	flushed = flush_nats_in_journal(sbi);
1563 
1564 	if (!flushed)
1565 		mutex_lock(&curseg->curseg_mutex);
1566 
1567 	/* 1) flush dirty nat caches */
1568 	list_for_each_safe(cur, n, &nm_i->dirty_nat_entries) {
1569 		struct nat_entry *ne;
1570 		nid_t nid;
1571 		struct f2fs_nat_entry raw_ne;
1572 		int offset = -1;
1573 		block_t old_blkaddr, new_blkaddr;
1574 
1575 		ne = list_entry(cur, struct nat_entry, list);
1576 		nid = nat_get_nid(ne);
1577 
1578 		if (nat_get_blkaddr(ne) == NEW_ADDR)
1579 			continue;
1580 		if (flushed)
1581 			goto to_nat_page;
1582 
1583 		/* if there is room for nat enries in curseg->sumpage */
1584 		offset = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 1);
1585 		if (offset >= 0) {
1586 			raw_ne = nat_in_journal(sum, offset);
1587 			old_blkaddr = le32_to_cpu(raw_ne.block_addr);
1588 			goto flush_now;
1589 		}
1590 to_nat_page:
1591 		if (!page || (start_nid > nid || nid > end_nid)) {
1592 			if (page) {
1593 				f2fs_put_page(page, 1);
1594 				page = NULL;
1595 			}
1596 			start_nid = START_NID(nid);
1597 			end_nid = start_nid + NAT_ENTRY_PER_BLOCK - 1;
1598 
1599 			/*
1600 			 * get nat block with dirty flag, increased reference
1601 			 * count, mapped and lock
1602 			 */
1603 			page = get_next_nat_page(sbi, start_nid);
1604 			nat_blk = page_address(page);
1605 		}
1606 
1607 		BUG_ON(!nat_blk);
1608 		raw_ne = nat_blk->entries[nid - start_nid];
1609 		old_blkaddr = le32_to_cpu(raw_ne.block_addr);
1610 flush_now:
1611 		new_blkaddr = nat_get_blkaddr(ne);
1612 
1613 		raw_ne.ino = cpu_to_le32(nat_get_ino(ne));
1614 		raw_ne.block_addr = cpu_to_le32(new_blkaddr);
1615 		raw_ne.version = nat_get_version(ne);
1616 
1617 		if (offset < 0) {
1618 			nat_blk->entries[nid - start_nid] = raw_ne;
1619 		} else {
1620 			nat_in_journal(sum, offset) = raw_ne;
1621 			nid_in_journal(sum, offset) = cpu_to_le32(nid);
1622 		}
1623 
1624 		if (nat_get_blkaddr(ne) == NULL_ADDR) {
1625 			write_lock(&nm_i->nat_tree_lock);
1626 			__del_from_nat_cache(nm_i, ne);
1627 			write_unlock(&nm_i->nat_tree_lock);
1628 
1629 			/* We can reuse this freed nid at this point */
1630 			add_free_nid(NM_I(sbi), nid);
1631 		} else {
1632 			write_lock(&nm_i->nat_tree_lock);
1633 			__clear_nat_cache_dirty(nm_i, ne);
1634 			ne->checkpointed = true;
1635 			write_unlock(&nm_i->nat_tree_lock);
1636 		}
1637 	}
1638 	if (!flushed)
1639 		mutex_unlock(&curseg->curseg_mutex);
1640 	f2fs_put_page(page, 1);
1641 
1642 	/* 2) shrink nat caches if necessary */
1643 	try_to_free_nats(sbi, nm_i->nat_cnt - NM_WOUT_THRESHOLD);
1644 }
1645 
1646 static int init_node_manager(struct f2fs_sb_info *sbi)
1647 {
1648 	struct f2fs_super_block *sb_raw = F2FS_RAW_SUPER(sbi);
1649 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1650 	unsigned char *version_bitmap;
1651 	unsigned int nat_segs, nat_blocks;
1652 
1653 	nm_i->nat_blkaddr = le32_to_cpu(sb_raw->nat_blkaddr);
1654 
1655 	/* segment_count_nat includes pair segment so divide to 2. */
1656 	nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
1657 	nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
1658 	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
1659 	nm_i->fcnt = 0;
1660 	nm_i->nat_cnt = 0;
1661 
1662 	INIT_LIST_HEAD(&nm_i->free_nid_list);
1663 	INIT_RADIX_TREE(&nm_i->nat_root, GFP_ATOMIC);
1664 	INIT_LIST_HEAD(&nm_i->nat_entries);
1665 	INIT_LIST_HEAD(&nm_i->dirty_nat_entries);
1666 
1667 	mutex_init(&nm_i->build_lock);
1668 	spin_lock_init(&nm_i->free_nid_list_lock);
1669 	rwlock_init(&nm_i->nat_tree_lock);
1670 
1671 	nm_i->bitmap_size = __bitmap_size(sbi, NAT_BITMAP);
1672 	nm_i->init_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
1673 	nm_i->next_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
1674 
1675 	nm_i->nat_bitmap = kzalloc(nm_i->bitmap_size, GFP_KERNEL);
1676 	if (!nm_i->nat_bitmap)
1677 		return -ENOMEM;
1678 	version_bitmap = __bitmap_ptr(sbi, NAT_BITMAP);
1679 	if (!version_bitmap)
1680 		return -EFAULT;
1681 
1682 	/* copy version bitmap */
1683 	memcpy(nm_i->nat_bitmap, version_bitmap, nm_i->bitmap_size);
1684 	return 0;
1685 }
1686 
1687 int build_node_manager(struct f2fs_sb_info *sbi)
1688 {
1689 	int err;
1690 
1691 	sbi->nm_info = kzalloc(sizeof(struct f2fs_nm_info), GFP_KERNEL);
1692 	if (!sbi->nm_info)
1693 		return -ENOMEM;
1694 
1695 	err = init_node_manager(sbi);
1696 	if (err)
1697 		return err;
1698 
1699 	build_free_nids(sbi);
1700 	return 0;
1701 }
1702 
1703 void destroy_node_manager(struct f2fs_sb_info *sbi)
1704 {
1705 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1706 	struct free_nid *i, *next_i;
1707 	struct nat_entry *natvec[NATVEC_SIZE];
1708 	nid_t nid = 0;
1709 	unsigned int found;
1710 
1711 	if (!nm_i)
1712 		return;
1713 
1714 	/* destroy free nid list */
1715 	spin_lock(&nm_i->free_nid_list_lock);
1716 	list_for_each_entry_safe(i, next_i, &nm_i->free_nid_list, list) {
1717 		BUG_ON(i->state == NID_ALLOC);
1718 		__del_from_free_nid_list(i);
1719 		nm_i->fcnt--;
1720 	}
1721 	BUG_ON(nm_i->fcnt);
1722 	spin_unlock(&nm_i->free_nid_list_lock);
1723 
1724 	/* destroy nat cache */
1725 	write_lock(&nm_i->nat_tree_lock);
1726 	while ((found = __gang_lookup_nat_cache(nm_i,
1727 					nid, NATVEC_SIZE, natvec))) {
1728 		unsigned idx;
1729 		for (idx = 0; idx < found; idx++) {
1730 			struct nat_entry *e = natvec[idx];
1731 			nid = nat_get_nid(e) + 1;
1732 			__del_from_nat_cache(nm_i, e);
1733 		}
1734 	}
1735 	BUG_ON(nm_i->nat_cnt);
1736 	write_unlock(&nm_i->nat_tree_lock);
1737 
1738 	kfree(nm_i->nat_bitmap);
1739 	sbi->nm_info = NULL;
1740 	kfree(nm_i);
1741 }
1742 
1743 int create_node_manager_caches(void)
1744 {
1745 	nat_entry_slab = f2fs_kmem_cache_create("nat_entry",
1746 			sizeof(struct nat_entry), NULL);
1747 	if (!nat_entry_slab)
1748 		return -ENOMEM;
1749 
1750 	free_nid_slab = f2fs_kmem_cache_create("free_nid",
1751 			sizeof(struct free_nid), NULL);
1752 	if (!free_nid_slab) {
1753 		kmem_cache_destroy(nat_entry_slab);
1754 		return -ENOMEM;
1755 	}
1756 	return 0;
1757 }
1758 
1759 void destroy_node_manager_caches(void)
1760 {
1761 	kmem_cache_destroy(free_nid_slab);
1762 	kmem_cache_destroy(nat_entry_slab);
1763 }
1764