xref: /openbmc/linux/fs/f2fs/node.c (revision 25c0a6e529b56ca010e1f46239edd07c1b484b63)
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 		f2fs_put_page(page, 0);
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 	memset(&ne, 0, sizeof(struct f2fs_nat_entry));
270 	ni->nid = nid;
271 
272 	/* Check nat cache */
273 	read_lock(&nm_i->nat_tree_lock);
274 	e = __lookup_nat_cache(nm_i, nid);
275 	if (e) {
276 		ni->ino = nat_get_ino(e);
277 		ni->blk_addr = nat_get_blkaddr(e);
278 		ni->version = nat_get_version(e);
279 	}
280 	read_unlock(&nm_i->nat_tree_lock);
281 	if (e)
282 		return;
283 
284 	/* Check current segment summary */
285 	mutex_lock(&curseg->curseg_mutex);
286 	i = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 0);
287 	if (i >= 0) {
288 		ne = nat_in_journal(sum, i);
289 		node_info_from_raw_nat(ni, &ne);
290 	}
291 	mutex_unlock(&curseg->curseg_mutex);
292 	if (i >= 0)
293 		goto cache;
294 
295 	/* Fill node_info from nat page */
296 	page = get_current_nat_page(sbi, start_nid);
297 	nat_blk = (struct f2fs_nat_block *)page_address(page);
298 	ne = nat_blk->entries[nid - start_nid];
299 	node_info_from_raw_nat(ni, &ne);
300 	f2fs_put_page(page, 1);
301 cache:
302 	/* cache nat entry */
303 	cache_nat_entry(NM_I(sbi), nid, &ne);
304 }
305 
306 /*
307  * The maximum depth is four.
308  * Offset[0] will have raw inode offset.
309  */
310 static int get_node_path(long block, int offset[4], unsigned int noffset[4])
311 {
312 	const long direct_index = ADDRS_PER_INODE;
313 	const long direct_blks = ADDRS_PER_BLOCK;
314 	const long dptrs_per_blk = NIDS_PER_BLOCK;
315 	const long indirect_blks = ADDRS_PER_BLOCK * NIDS_PER_BLOCK;
316 	const long dindirect_blks = indirect_blks * NIDS_PER_BLOCK;
317 	int n = 0;
318 	int level = 0;
319 
320 	noffset[0] = 0;
321 
322 	if (block < direct_index) {
323 		offset[n] = block;
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 mode)
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 	if (level != 0)
406 		nids[1] = get_nid(parent, offset[0], true);
407 	dn->inode_page = npage[0];
408 	dn->inode_page_locked = true;
409 
410 	/* get indirect or direct nodes */
411 	for (i = 1; i <= level; i++) {
412 		bool done = false;
413 
414 		if (!nids[i] && mode == ALLOC_NODE) {
415 			mutex_lock_op(sbi, NODE_NEW);
416 
417 			/* alloc new node */
418 			if (!alloc_nid(sbi, &(nids[i]))) {
419 				mutex_unlock_op(sbi, NODE_NEW);
420 				err = -ENOSPC;
421 				goto release_pages;
422 			}
423 
424 			dn->nid = nids[i];
425 			npage[i] = new_node_page(dn, noffset[i]);
426 			if (IS_ERR(npage[i])) {
427 				alloc_nid_failed(sbi, nids[i]);
428 				mutex_unlock_op(sbi, NODE_NEW);
429 				err = PTR_ERR(npage[i]);
430 				goto release_pages;
431 			}
432 
433 			set_nid(parent, offset[i - 1], nids[i], i == 1);
434 			alloc_nid_done(sbi, nids[i]);
435 			mutex_unlock_op(sbi, NODE_NEW);
436 			done = true;
437 		} else if (mode == LOOKUP_NODE_RA && i == level && level > 1) {
438 			npage[i] = get_node_page_ra(parent, offset[i - 1]);
439 			if (IS_ERR(npage[i])) {
440 				err = PTR_ERR(npage[i]);
441 				goto release_pages;
442 			}
443 			done = true;
444 		}
445 		if (i == 1) {
446 			dn->inode_page_locked = false;
447 			unlock_page(parent);
448 		} else {
449 			f2fs_put_page(parent, 1);
450 		}
451 
452 		if (!done) {
453 			npage[i] = get_node_page(sbi, nids[i]);
454 			if (IS_ERR(npage[i])) {
455 				err = PTR_ERR(npage[i]);
456 				f2fs_put_page(npage[0], 0);
457 				goto release_out;
458 			}
459 		}
460 		if (i < level) {
461 			parent = npage[i];
462 			nids[i + 1] = get_nid(parent, offset[i], false);
463 		}
464 	}
465 	dn->nid = nids[level];
466 	dn->ofs_in_node = offset[level];
467 	dn->node_page = npage[level];
468 	dn->data_blkaddr = datablock_addr(dn->node_page, dn->ofs_in_node);
469 	return 0;
470 
471 release_pages:
472 	f2fs_put_page(parent, 1);
473 	if (i > 1)
474 		f2fs_put_page(npage[0], 0);
475 release_out:
476 	dn->inode_page = NULL;
477 	dn->node_page = NULL;
478 	return err;
479 }
480 
481 static void truncate_node(struct dnode_of_data *dn)
482 {
483 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
484 	struct node_info ni;
485 
486 	get_node_info(sbi, dn->nid, &ni);
487 	if (dn->inode->i_blocks == 0) {
488 		BUG_ON(ni.blk_addr != NULL_ADDR);
489 		goto invalidate;
490 	}
491 	BUG_ON(ni.blk_addr == NULL_ADDR);
492 
493 	/* Deallocate node address */
494 	invalidate_blocks(sbi, ni.blk_addr);
495 	dec_valid_node_count(sbi, dn->inode, 1);
496 	set_node_addr(sbi, &ni, NULL_ADDR);
497 
498 	if (dn->nid == dn->inode->i_ino) {
499 		remove_orphan_inode(sbi, dn->nid);
500 		dec_valid_inode_count(sbi);
501 	} else {
502 		sync_inode_page(dn);
503 	}
504 invalidate:
505 	clear_node_page_dirty(dn->node_page);
506 	F2FS_SET_SB_DIRT(sbi);
507 
508 	f2fs_put_page(dn->node_page, 1);
509 	dn->node_page = NULL;
510 }
511 
512 static int truncate_dnode(struct dnode_of_data *dn)
513 {
514 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
515 	struct page *page;
516 
517 	if (dn->nid == 0)
518 		return 1;
519 
520 	/* get direct node */
521 	page = get_node_page(sbi, dn->nid);
522 	if (IS_ERR(page) && PTR_ERR(page) == -ENOENT)
523 		return 1;
524 	else if (IS_ERR(page))
525 		return PTR_ERR(page);
526 
527 	/* Make dnode_of_data for parameter */
528 	dn->node_page = page;
529 	dn->ofs_in_node = 0;
530 	truncate_data_blocks(dn);
531 	truncate_node(dn);
532 	return 1;
533 }
534 
535 static int truncate_nodes(struct dnode_of_data *dn, unsigned int nofs,
536 						int ofs, int depth)
537 {
538 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
539 	struct dnode_of_data rdn = *dn;
540 	struct page *page;
541 	struct f2fs_node *rn;
542 	nid_t child_nid;
543 	unsigned int child_nofs;
544 	int freed = 0;
545 	int i, ret;
546 
547 	if (dn->nid == 0)
548 		return NIDS_PER_BLOCK + 1;
549 
550 	page = get_node_page(sbi, dn->nid);
551 	if (IS_ERR(page))
552 		return PTR_ERR(page);
553 
554 	rn = (struct f2fs_node *)page_address(page);
555 	if (depth < 3) {
556 		for (i = ofs; i < NIDS_PER_BLOCK; i++, freed++) {
557 			child_nid = le32_to_cpu(rn->in.nid[i]);
558 			if (child_nid == 0)
559 				continue;
560 			rdn.nid = child_nid;
561 			ret = truncate_dnode(&rdn);
562 			if (ret < 0)
563 				goto out_err;
564 			set_nid(page, i, 0, false);
565 		}
566 	} else {
567 		child_nofs = nofs + ofs * (NIDS_PER_BLOCK + 1) + 1;
568 		for (i = ofs; i < NIDS_PER_BLOCK; i++) {
569 			child_nid = le32_to_cpu(rn->in.nid[i]);
570 			if (child_nid == 0) {
571 				child_nofs += NIDS_PER_BLOCK + 1;
572 				continue;
573 			}
574 			rdn.nid = child_nid;
575 			ret = truncate_nodes(&rdn, child_nofs, 0, depth - 1);
576 			if (ret == (NIDS_PER_BLOCK + 1)) {
577 				set_nid(page, i, 0, false);
578 				child_nofs += ret;
579 			} else if (ret < 0 && ret != -ENOENT) {
580 				goto out_err;
581 			}
582 		}
583 		freed = child_nofs;
584 	}
585 
586 	if (!ofs) {
587 		/* remove current indirect node */
588 		dn->node_page = page;
589 		truncate_node(dn);
590 		freed++;
591 	} else {
592 		f2fs_put_page(page, 1);
593 	}
594 	return freed;
595 
596 out_err:
597 	f2fs_put_page(page, 1);
598 	return ret;
599 }
600 
601 static int truncate_partial_nodes(struct dnode_of_data *dn,
602 			struct f2fs_inode *ri, int *offset, int depth)
603 {
604 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
605 	struct page *pages[2];
606 	nid_t nid[3];
607 	nid_t child_nid;
608 	int err = 0;
609 	int i;
610 	int idx = depth - 2;
611 
612 	nid[0] = le32_to_cpu(ri->i_nid[offset[0] - NODE_DIR1_BLOCK]);
613 	if (!nid[0])
614 		return 0;
615 
616 	/* get indirect nodes in the path */
617 	for (i = 0; i < depth - 1; i++) {
618 		/* refernece count'll be increased */
619 		pages[i] = get_node_page(sbi, nid[i]);
620 		if (IS_ERR(pages[i])) {
621 			depth = i + 1;
622 			err = PTR_ERR(pages[i]);
623 			goto fail;
624 		}
625 		nid[i + 1] = get_nid(pages[i], offset[i + 1], false);
626 	}
627 
628 	/* free direct nodes linked to a partial indirect node */
629 	for (i = offset[depth - 1]; i < NIDS_PER_BLOCK; i++) {
630 		child_nid = get_nid(pages[idx], i, false);
631 		if (!child_nid)
632 			continue;
633 		dn->nid = child_nid;
634 		err = truncate_dnode(dn);
635 		if (err < 0)
636 			goto fail;
637 		set_nid(pages[idx], i, 0, false);
638 	}
639 
640 	if (offset[depth - 1] == 0) {
641 		dn->node_page = pages[idx];
642 		dn->nid = nid[idx];
643 		truncate_node(dn);
644 	} else {
645 		f2fs_put_page(pages[idx], 1);
646 	}
647 	offset[idx]++;
648 	offset[depth - 1] = 0;
649 fail:
650 	for (i = depth - 3; i >= 0; i--)
651 		f2fs_put_page(pages[i], 1);
652 	return err;
653 }
654 
655 /*
656  * All the block addresses of data and nodes should be nullified.
657  */
658 int truncate_inode_blocks(struct inode *inode, pgoff_t from)
659 {
660 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
661 	int err = 0, cont = 1;
662 	int level, offset[4], noffset[4];
663 	unsigned int nofs = 0;
664 	struct f2fs_node *rn;
665 	struct dnode_of_data dn;
666 	struct page *page;
667 
668 	level = get_node_path(from, offset, noffset);
669 
670 	page = get_node_page(sbi, inode->i_ino);
671 	if (IS_ERR(page))
672 		return PTR_ERR(page);
673 
674 	set_new_dnode(&dn, inode, page, NULL, 0);
675 	unlock_page(page);
676 
677 	rn = page_address(page);
678 	switch (level) {
679 	case 0:
680 	case 1:
681 		nofs = noffset[1];
682 		break;
683 	case 2:
684 		nofs = noffset[1];
685 		if (!offset[level - 1])
686 			goto skip_partial;
687 		err = truncate_partial_nodes(&dn, &rn->i, offset, level);
688 		if (err < 0 && err != -ENOENT)
689 			goto fail;
690 		nofs += 1 + NIDS_PER_BLOCK;
691 		break;
692 	case 3:
693 		nofs = 5 + 2 * NIDS_PER_BLOCK;
694 		if (!offset[level - 1])
695 			goto skip_partial;
696 		err = truncate_partial_nodes(&dn, &rn->i, offset, level);
697 		if (err < 0 && err != -ENOENT)
698 			goto fail;
699 		break;
700 	default:
701 		BUG();
702 	}
703 
704 skip_partial:
705 	while (cont) {
706 		dn.nid = le32_to_cpu(rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK]);
707 		switch (offset[0]) {
708 		case NODE_DIR1_BLOCK:
709 		case NODE_DIR2_BLOCK:
710 			err = truncate_dnode(&dn);
711 			break;
712 
713 		case NODE_IND1_BLOCK:
714 		case NODE_IND2_BLOCK:
715 			err = truncate_nodes(&dn, nofs, offset[1], 2);
716 			break;
717 
718 		case NODE_DIND_BLOCK:
719 			err = truncate_nodes(&dn, nofs, offset[1], 3);
720 			cont = 0;
721 			break;
722 
723 		default:
724 			BUG();
725 		}
726 		if (err < 0 && err != -ENOENT)
727 			goto fail;
728 		if (offset[1] == 0 &&
729 				rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK]) {
730 			lock_page(page);
731 			wait_on_page_writeback(page);
732 			rn->i.i_nid[offset[0] - NODE_DIR1_BLOCK] = 0;
733 			set_page_dirty(page);
734 			unlock_page(page);
735 		}
736 		offset[1] = 0;
737 		offset[0]++;
738 		nofs += err;
739 	}
740 fail:
741 	f2fs_put_page(page, 0);
742 	return err > 0 ? 0 : err;
743 }
744 
745 int remove_inode_page(struct inode *inode)
746 {
747 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
748 	struct page *page;
749 	nid_t ino = inode->i_ino;
750 	struct dnode_of_data dn;
751 
752 	mutex_lock_op(sbi, NODE_TRUNC);
753 	page = get_node_page(sbi, ino);
754 	if (IS_ERR(page)) {
755 		mutex_unlock_op(sbi, NODE_TRUNC);
756 		return PTR_ERR(page);
757 	}
758 
759 	if (F2FS_I(inode)->i_xattr_nid) {
760 		nid_t nid = F2FS_I(inode)->i_xattr_nid;
761 		struct page *npage = get_node_page(sbi, nid);
762 
763 		if (IS_ERR(npage)) {
764 			mutex_unlock_op(sbi, NODE_TRUNC);
765 			return PTR_ERR(npage);
766 		}
767 
768 		F2FS_I(inode)->i_xattr_nid = 0;
769 		set_new_dnode(&dn, inode, page, npage, nid);
770 		dn.inode_page_locked = 1;
771 		truncate_node(&dn);
772 	}
773 
774 	/* 0 is possible, after f2fs_new_inode() is failed */
775 	BUG_ON(inode->i_blocks != 0 && inode->i_blocks != 1);
776 	set_new_dnode(&dn, inode, page, page, ino);
777 	truncate_node(&dn);
778 
779 	mutex_unlock_op(sbi, NODE_TRUNC);
780 	return 0;
781 }
782 
783 int new_inode_page(struct inode *inode, const struct qstr *name)
784 {
785 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
786 	struct page *page;
787 	struct dnode_of_data dn;
788 
789 	/* allocate inode page for new inode */
790 	set_new_dnode(&dn, inode, NULL, NULL, inode->i_ino);
791 	mutex_lock_op(sbi, NODE_NEW);
792 	page = new_node_page(&dn, 0);
793 	init_dent_inode(name, page);
794 	mutex_unlock_op(sbi, NODE_NEW);
795 	if (IS_ERR(page))
796 		return PTR_ERR(page);
797 	f2fs_put_page(page, 1);
798 	return 0;
799 }
800 
801 struct page *new_node_page(struct dnode_of_data *dn, unsigned int ofs)
802 {
803 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
804 	struct address_space *mapping = sbi->node_inode->i_mapping;
805 	struct node_info old_ni, new_ni;
806 	struct page *page;
807 	int err;
808 
809 	if (is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC))
810 		return ERR_PTR(-EPERM);
811 
812 	page = grab_cache_page(mapping, dn->nid);
813 	if (!page)
814 		return ERR_PTR(-ENOMEM);
815 
816 	get_node_info(sbi, dn->nid, &old_ni);
817 
818 	SetPageUptodate(page);
819 	fill_node_footer(page, dn->nid, dn->inode->i_ino, ofs, true);
820 
821 	/* Reinitialize old_ni with new node page */
822 	BUG_ON(old_ni.blk_addr != NULL_ADDR);
823 	new_ni = old_ni;
824 	new_ni.ino = dn->inode->i_ino;
825 
826 	if (!inc_valid_node_count(sbi, dn->inode, 1)) {
827 		err = -ENOSPC;
828 		goto fail;
829 	}
830 	set_node_addr(sbi, &new_ni, NEW_ADDR);
831 	set_cold_node(dn->inode, page);
832 
833 	dn->node_page = page;
834 	sync_inode_page(dn);
835 	set_page_dirty(page);
836 	if (ofs == 0)
837 		inc_valid_inode_count(sbi);
838 
839 	return page;
840 
841 fail:
842 	clear_node_page_dirty(page);
843 	f2fs_put_page(page, 1);
844 	return ERR_PTR(err);
845 }
846 
847 static int read_node_page(struct page *page, int type)
848 {
849 	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
850 	struct node_info ni;
851 
852 	get_node_info(sbi, page->index, &ni);
853 
854 	if (ni.blk_addr == NULL_ADDR)
855 		return -ENOENT;
856 	return f2fs_readpage(sbi, page, ni.blk_addr, type);
857 }
858 
859 /*
860  * Readahead a node page
861  */
862 void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid)
863 {
864 	struct address_space *mapping = sbi->node_inode->i_mapping;
865 	struct page *apage;
866 
867 	apage = find_get_page(mapping, nid);
868 	if (apage && PageUptodate(apage))
869 		goto release_out;
870 	f2fs_put_page(apage, 0);
871 
872 	apage = grab_cache_page(mapping, nid);
873 	if (!apage)
874 		return;
875 
876 	if (read_node_page(apage, READA))
877 		unlock_page(apage);
878 
879 release_out:
880 	f2fs_put_page(apage, 0);
881 	return;
882 }
883 
884 struct page *get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid)
885 {
886 	int err;
887 	struct page *page;
888 	struct address_space *mapping = sbi->node_inode->i_mapping;
889 
890 	page = grab_cache_page(mapping, nid);
891 	if (!page)
892 		return ERR_PTR(-ENOMEM);
893 
894 	err = read_node_page(page, READ_SYNC);
895 	if (err) {
896 		f2fs_put_page(page, 1);
897 		return ERR_PTR(err);
898 	}
899 
900 	BUG_ON(nid != nid_of_node(page));
901 	mark_page_accessed(page);
902 	return page;
903 }
904 
905 /*
906  * Return a locked page for the desired node page.
907  * And, readahead MAX_RA_NODE number of node pages.
908  */
909 struct page *get_node_page_ra(struct page *parent, int start)
910 {
911 	struct f2fs_sb_info *sbi = F2FS_SB(parent->mapping->host->i_sb);
912 	struct address_space *mapping = sbi->node_inode->i_mapping;
913 	int i, end;
914 	int err = 0;
915 	nid_t nid;
916 	struct page *page;
917 
918 	/* First, try getting the desired direct node. */
919 	nid = get_nid(parent, start, false);
920 	if (!nid)
921 		return ERR_PTR(-ENOENT);
922 
923 repeat:
924 	page = grab_cache_page(mapping, nid);
925 	if (!page)
926 		return ERR_PTR(-ENOMEM);
927 	else if (PageUptodate(page))
928 		goto page_hit;
929 
930 	err = read_node_page(page, READ_SYNC);
931 	unlock_page(page);
932 	if (err) {
933 		f2fs_put_page(page, 0);
934 		return ERR_PTR(err);
935 	}
936 
937 	/* Then, try readahead for siblings of the desired node */
938 	end = start + MAX_RA_NODE;
939 	end = min(end, NIDS_PER_BLOCK);
940 	for (i = start + 1; i < end; i++) {
941 		nid = get_nid(parent, i, false);
942 		if (!nid)
943 			continue;
944 		ra_node_page(sbi, nid);
945 	}
946 
947 	lock_page(page);
948 
949 page_hit:
950 	if (PageError(page)) {
951 		f2fs_put_page(page, 1);
952 		return ERR_PTR(-EIO);
953 	}
954 
955 	/* Has the page been truncated? */
956 	if (page->mapping != mapping) {
957 		f2fs_put_page(page, 1);
958 		goto repeat;
959 	}
960 	return page;
961 }
962 
963 void sync_inode_page(struct dnode_of_data *dn)
964 {
965 	if (IS_INODE(dn->node_page) || dn->inode_page == dn->node_page) {
966 		update_inode(dn->inode, dn->node_page);
967 	} else if (dn->inode_page) {
968 		if (!dn->inode_page_locked)
969 			lock_page(dn->inode_page);
970 		update_inode(dn->inode, dn->inode_page);
971 		if (!dn->inode_page_locked)
972 			unlock_page(dn->inode_page);
973 	} else {
974 		f2fs_write_inode(dn->inode, NULL);
975 	}
976 }
977 
978 int sync_node_pages(struct f2fs_sb_info *sbi, nid_t ino,
979 					struct writeback_control *wbc)
980 {
981 	struct address_space *mapping = sbi->node_inode->i_mapping;
982 	pgoff_t index, end;
983 	struct pagevec pvec;
984 	int step = ino ? 2 : 0;
985 	int nwritten = 0, wrote = 0;
986 
987 	pagevec_init(&pvec, 0);
988 
989 next_step:
990 	index = 0;
991 	end = LONG_MAX;
992 
993 	while (index <= end) {
994 		int i, nr_pages;
995 		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
996 				PAGECACHE_TAG_DIRTY,
997 				min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
998 		if (nr_pages == 0)
999 			break;
1000 
1001 		for (i = 0; i < nr_pages; i++) {
1002 			struct page *page = pvec.pages[i];
1003 
1004 			/*
1005 			 * flushing sequence with step:
1006 			 * 0. indirect nodes
1007 			 * 1. dentry dnodes
1008 			 * 2. file dnodes
1009 			 */
1010 			if (step == 0 && IS_DNODE(page))
1011 				continue;
1012 			if (step == 1 && (!IS_DNODE(page) ||
1013 						is_cold_node(page)))
1014 				continue;
1015 			if (step == 2 && (!IS_DNODE(page) ||
1016 						!is_cold_node(page)))
1017 				continue;
1018 
1019 			/*
1020 			 * If an fsync mode,
1021 			 * we should not skip writing node pages.
1022 			 */
1023 			if (ino && ino_of_node(page) == ino)
1024 				lock_page(page);
1025 			else if (!trylock_page(page))
1026 				continue;
1027 
1028 			if (unlikely(page->mapping != mapping)) {
1029 continue_unlock:
1030 				unlock_page(page);
1031 				continue;
1032 			}
1033 			if (ino && ino_of_node(page) != ino)
1034 				goto continue_unlock;
1035 
1036 			if (!PageDirty(page)) {
1037 				/* someone wrote it for us */
1038 				goto continue_unlock;
1039 			}
1040 
1041 			if (!clear_page_dirty_for_io(page))
1042 				goto continue_unlock;
1043 
1044 			/* called by fsync() */
1045 			if (ino && IS_DNODE(page)) {
1046 				int mark = !is_checkpointed_node(sbi, ino);
1047 				set_fsync_mark(page, 1);
1048 				if (IS_INODE(page))
1049 					set_dentry_mark(page, mark);
1050 				nwritten++;
1051 			} else {
1052 				set_fsync_mark(page, 0);
1053 				set_dentry_mark(page, 0);
1054 			}
1055 			mapping->a_ops->writepage(page, wbc);
1056 			wrote++;
1057 
1058 			if (--wbc->nr_to_write == 0)
1059 				break;
1060 		}
1061 		pagevec_release(&pvec);
1062 		cond_resched();
1063 
1064 		if (wbc->nr_to_write == 0) {
1065 			step = 2;
1066 			break;
1067 		}
1068 	}
1069 
1070 	if (step < 2) {
1071 		step++;
1072 		goto next_step;
1073 	}
1074 
1075 	if (wrote)
1076 		f2fs_submit_bio(sbi, NODE, wbc->sync_mode == WB_SYNC_ALL);
1077 
1078 	return nwritten;
1079 }
1080 
1081 static int f2fs_write_node_page(struct page *page,
1082 				struct writeback_control *wbc)
1083 {
1084 	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
1085 	nid_t nid;
1086 	block_t new_addr;
1087 	struct node_info ni;
1088 
1089 	if (wbc->for_reclaim) {
1090 		dec_page_count(sbi, F2FS_DIRTY_NODES);
1091 		wbc->pages_skipped++;
1092 		set_page_dirty(page);
1093 		return AOP_WRITEPAGE_ACTIVATE;
1094 	}
1095 
1096 	wait_on_page_writeback(page);
1097 
1098 	mutex_lock_op(sbi, NODE_WRITE);
1099 
1100 	/* get old block addr of this node page */
1101 	nid = nid_of_node(page);
1102 	BUG_ON(page->index != nid);
1103 
1104 	get_node_info(sbi, nid, &ni);
1105 
1106 	/* This page is already truncated */
1107 	if (ni.blk_addr == NULL_ADDR)
1108 		goto out;
1109 
1110 	set_page_writeback(page);
1111 
1112 	/* insert node offset */
1113 	write_node_page(sbi, page, nid, ni.blk_addr, &new_addr);
1114 	set_node_addr(sbi, &ni, new_addr);
1115 out:
1116 	dec_page_count(sbi, F2FS_DIRTY_NODES);
1117 	mutex_unlock_op(sbi, NODE_WRITE);
1118 	unlock_page(page);
1119 	return 0;
1120 }
1121 
1122 /*
1123  * It is very important to gather dirty pages and write at once, so that we can
1124  * submit a big bio without interfering other data writes.
1125  * Be default, 512 pages (2MB), a segment size, is quite reasonable.
1126  */
1127 #define COLLECT_DIRTY_NODES	512
1128 static int f2fs_write_node_pages(struct address_space *mapping,
1129 			    struct writeback_control *wbc)
1130 {
1131 	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1132 	struct block_device *bdev = sbi->sb->s_bdev;
1133 	long nr_to_write = wbc->nr_to_write;
1134 
1135 	/* First check balancing cached NAT entries */
1136 	if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) {
1137 		write_checkpoint(sbi, false);
1138 		return 0;
1139 	}
1140 
1141 	/* collect a number of dirty node pages and write together */
1142 	if (get_pages(sbi, F2FS_DIRTY_NODES) < COLLECT_DIRTY_NODES)
1143 		return 0;
1144 
1145 	/* if mounting is failed, skip writing node pages */
1146 	wbc->nr_to_write = bio_get_nr_vecs(bdev);
1147 	sync_node_pages(sbi, 0, wbc);
1148 	wbc->nr_to_write = nr_to_write -
1149 		(bio_get_nr_vecs(bdev) - wbc->nr_to_write);
1150 	return 0;
1151 }
1152 
1153 static int f2fs_set_node_page_dirty(struct page *page)
1154 {
1155 	struct address_space *mapping = page->mapping;
1156 	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1157 
1158 	SetPageUptodate(page);
1159 	if (!PageDirty(page)) {
1160 		__set_page_dirty_nobuffers(page);
1161 		inc_page_count(sbi, F2FS_DIRTY_NODES);
1162 		SetPagePrivate(page);
1163 		return 1;
1164 	}
1165 	return 0;
1166 }
1167 
1168 static void f2fs_invalidate_node_page(struct page *page, unsigned long offset)
1169 {
1170 	struct inode *inode = page->mapping->host;
1171 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
1172 	if (PageDirty(page))
1173 		dec_page_count(sbi, F2FS_DIRTY_NODES);
1174 	ClearPagePrivate(page);
1175 }
1176 
1177 static int f2fs_release_node_page(struct page *page, gfp_t wait)
1178 {
1179 	ClearPagePrivate(page);
1180 	return 0;
1181 }
1182 
1183 /*
1184  * Structure of the f2fs node operations
1185  */
1186 const struct address_space_operations f2fs_node_aops = {
1187 	.writepage	= f2fs_write_node_page,
1188 	.writepages	= f2fs_write_node_pages,
1189 	.set_page_dirty	= f2fs_set_node_page_dirty,
1190 	.invalidatepage	= f2fs_invalidate_node_page,
1191 	.releasepage	= f2fs_release_node_page,
1192 };
1193 
1194 static struct free_nid *__lookup_free_nid_list(nid_t n, struct list_head *head)
1195 {
1196 	struct list_head *this;
1197 	struct free_nid *i;
1198 	list_for_each(this, head) {
1199 		i = list_entry(this, struct free_nid, list);
1200 		if (i->nid == n)
1201 			return i;
1202 	}
1203 	return NULL;
1204 }
1205 
1206 static void __del_from_free_nid_list(struct free_nid *i)
1207 {
1208 	list_del(&i->list);
1209 	kmem_cache_free(free_nid_slab, i);
1210 }
1211 
1212 static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
1213 {
1214 	struct free_nid *i;
1215 
1216 	if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
1217 		return 0;
1218 retry:
1219 	i = kmem_cache_alloc(free_nid_slab, GFP_NOFS);
1220 	if (!i) {
1221 		cond_resched();
1222 		goto retry;
1223 	}
1224 	i->nid = nid;
1225 	i->state = NID_NEW;
1226 
1227 	spin_lock(&nm_i->free_nid_list_lock);
1228 	if (__lookup_free_nid_list(nid, &nm_i->free_nid_list)) {
1229 		spin_unlock(&nm_i->free_nid_list_lock);
1230 		kmem_cache_free(free_nid_slab, i);
1231 		return 0;
1232 	}
1233 	list_add_tail(&i->list, &nm_i->free_nid_list);
1234 	nm_i->fcnt++;
1235 	spin_unlock(&nm_i->free_nid_list_lock);
1236 	return 1;
1237 }
1238 
1239 static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
1240 {
1241 	struct free_nid *i;
1242 	spin_lock(&nm_i->free_nid_list_lock);
1243 	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
1244 	if (i && i->state == NID_NEW) {
1245 		__del_from_free_nid_list(i);
1246 		nm_i->fcnt--;
1247 	}
1248 	spin_unlock(&nm_i->free_nid_list_lock);
1249 }
1250 
1251 static int scan_nat_page(struct f2fs_nm_info *nm_i,
1252 			struct page *nat_page, nid_t start_nid)
1253 {
1254 	struct f2fs_nat_block *nat_blk = page_address(nat_page);
1255 	block_t blk_addr;
1256 	int fcnt = 0;
1257 	int i;
1258 
1259 	/* 0 nid should not be used */
1260 	if (start_nid == 0)
1261 		++start_nid;
1262 
1263 	i = start_nid % NAT_ENTRY_PER_BLOCK;
1264 
1265 	for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
1266 		blk_addr  = le32_to_cpu(nat_blk->entries[i].block_addr);
1267 		BUG_ON(blk_addr == NEW_ADDR);
1268 		if (blk_addr == NULL_ADDR)
1269 			fcnt += add_free_nid(nm_i, start_nid);
1270 	}
1271 	return fcnt;
1272 }
1273 
1274 static void build_free_nids(struct f2fs_sb_info *sbi)
1275 {
1276 	struct free_nid *fnid, *next_fnid;
1277 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1278 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1279 	struct f2fs_summary_block *sum = curseg->sum_blk;
1280 	nid_t nid = 0;
1281 	bool is_cycled = false;
1282 	int fcnt = 0;
1283 	int i;
1284 
1285 	nid = nm_i->next_scan_nid;
1286 	nm_i->init_scan_nid = nid;
1287 
1288 	ra_nat_pages(sbi, nid);
1289 
1290 	while (1) {
1291 		struct page *page = get_current_nat_page(sbi, nid);
1292 
1293 		fcnt += scan_nat_page(nm_i, page, nid);
1294 		f2fs_put_page(page, 1);
1295 
1296 		nid += (NAT_ENTRY_PER_BLOCK - (nid % NAT_ENTRY_PER_BLOCK));
1297 
1298 		if (nid >= nm_i->max_nid) {
1299 			nid = 0;
1300 			is_cycled = true;
1301 		}
1302 		if (fcnt > MAX_FREE_NIDS)
1303 			break;
1304 		if (is_cycled && nm_i->init_scan_nid <= nid)
1305 			break;
1306 	}
1307 
1308 	nm_i->next_scan_nid = nid;
1309 
1310 	/* find free nids from current sum_pages */
1311 	mutex_lock(&curseg->curseg_mutex);
1312 	for (i = 0; i < nats_in_cursum(sum); i++) {
1313 		block_t addr = le32_to_cpu(nat_in_journal(sum, i).block_addr);
1314 		nid = le32_to_cpu(nid_in_journal(sum, i));
1315 		if (addr == NULL_ADDR)
1316 			add_free_nid(nm_i, nid);
1317 		else
1318 			remove_free_nid(nm_i, nid);
1319 	}
1320 	mutex_unlock(&curseg->curseg_mutex);
1321 
1322 	/* remove the free nids from current allocated nids */
1323 	list_for_each_entry_safe(fnid, next_fnid, &nm_i->free_nid_list, list) {
1324 		struct nat_entry *ne;
1325 
1326 		read_lock(&nm_i->nat_tree_lock);
1327 		ne = __lookup_nat_cache(nm_i, fnid->nid);
1328 		if (ne && nat_get_blkaddr(ne) != NULL_ADDR)
1329 			remove_free_nid(nm_i, fnid->nid);
1330 		read_unlock(&nm_i->nat_tree_lock);
1331 	}
1332 }
1333 
1334 /*
1335  * If this function returns success, caller can obtain a new nid
1336  * from second parameter of this function.
1337  * The returned nid could be used ino as well as nid when inode is created.
1338  */
1339 bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
1340 {
1341 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1342 	struct free_nid *i = NULL;
1343 	struct list_head *this;
1344 retry:
1345 	mutex_lock(&nm_i->build_lock);
1346 	if (!nm_i->fcnt) {
1347 		/* scan NAT in order to build free nid list */
1348 		build_free_nids(sbi);
1349 		if (!nm_i->fcnt) {
1350 			mutex_unlock(&nm_i->build_lock);
1351 			return false;
1352 		}
1353 	}
1354 	mutex_unlock(&nm_i->build_lock);
1355 
1356 	/*
1357 	 * We check fcnt again since previous check is racy as
1358 	 * we didn't hold free_nid_list_lock. So other thread
1359 	 * could consume all of free nids.
1360 	 */
1361 	spin_lock(&nm_i->free_nid_list_lock);
1362 	if (!nm_i->fcnt) {
1363 		spin_unlock(&nm_i->free_nid_list_lock);
1364 		goto retry;
1365 	}
1366 
1367 	BUG_ON(list_empty(&nm_i->free_nid_list));
1368 	list_for_each(this, &nm_i->free_nid_list) {
1369 		i = list_entry(this, struct free_nid, list);
1370 		if (i->state == NID_NEW)
1371 			break;
1372 	}
1373 
1374 	BUG_ON(i->state != NID_NEW);
1375 	*nid = i->nid;
1376 	i->state = NID_ALLOC;
1377 	nm_i->fcnt--;
1378 	spin_unlock(&nm_i->free_nid_list_lock);
1379 	return true;
1380 }
1381 
1382 /*
1383  * alloc_nid() should be called prior to this function.
1384  */
1385 void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
1386 {
1387 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1388 	struct free_nid *i;
1389 
1390 	spin_lock(&nm_i->free_nid_list_lock);
1391 	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
1392 	if (i) {
1393 		BUG_ON(i->state != NID_ALLOC);
1394 		__del_from_free_nid_list(i);
1395 	}
1396 	spin_unlock(&nm_i->free_nid_list_lock);
1397 }
1398 
1399 /*
1400  * alloc_nid() should be called prior to this function.
1401  */
1402 void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
1403 {
1404 	alloc_nid_done(sbi, nid);
1405 	add_free_nid(NM_I(sbi), nid);
1406 }
1407 
1408 void recover_node_page(struct f2fs_sb_info *sbi, struct page *page,
1409 		struct f2fs_summary *sum, struct node_info *ni,
1410 		block_t new_blkaddr)
1411 {
1412 	rewrite_node_page(sbi, page, sum, ni->blk_addr, new_blkaddr);
1413 	set_node_addr(sbi, ni, new_blkaddr);
1414 	clear_node_page_dirty(page);
1415 }
1416 
1417 int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
1418 {
1419 	struct address_space *mapping = sbi->node_inode->i_mapping;
1420 	struct f2fs_node *src, *dst;
1421 	nid_t ino = ino_of_node(page);
1422 	struct node_info old_ni, new_ni;
1423 	struct page *ipage;
1424 
1425 	ipage = grab_cache_page(mapping, ino);
1426 	if (!ipage)
1427 		return -ENOMEM;
1428 
1429 	/* Should not use this inode  from free nid list */
1430 	remove_free_nid(NM_I(sbi), ino);
1431 
1432 	get_node_info(sbi, ino, &old_ni);
1433 	SetPageUptodate(ipage);
1434 	fill_node_footer(ipage, ino, ino, 0, true);
1435 
1436 	src = (struct f2fs_node *)page_address(page);
1437 	dst = (struct f2fs_node *)page_address(ipage);
1438 
1439 	memcpy(dst, src, (unsigned long)&src->i.i_ext - (unsigned long)&src->i);
1440 	dst->i.i_size = 0;
1441 	dst->i.i_blocks = cpu_to_le64(1);
1442 	dst->i.i_links = cpu_to_le32(1);
1443 	dst->i.i_xattr_nid = 0;
1444 
1445 	new_ni = old_ni;
1446 	new_ni.ino = ino;
1447 
1448 	set_node_addr(sbi, &new_ni, NEW_ADDR);
1449 	inc_valid_inode_count(sbi);
1450 
1451 	f2fs_put_page(ipage, 1);
1452 	return 0;
1453 }
1454 
1455 int restore_node_summary(struct f2fs_sb_info *sbi,
1456 			unsigned int segno, struct f2fs_summary_block *sum)
1457 {
1458 	struct f2fs_node *rn;
1459 	struct f2fs_summary *sum_entry;
1460 	struct page *page;
1461 	block_t addr;
1462 	int i, last_offset;
1463 
1464 	/* alloc temporal page for read node */
1465 	page = alloc_page(GFP_NOFS | __GFP_ZERO);
1466 	if (IS_ERR(page))
1467 		return PTR_ERR(page);
1468 	lock_page(page);
1469 
1470 	/* scan the node segment */
1471 	last_offset = sbi->blocks_per_seg;
1472 	addr = START_BLOCK(sbi, segno);
1473 	sum_entry = &sum->entries[0];
1474 
1475 	for (i = 0; i < last_offset; i++, sum_entry++) {
1476 		if (f2fs_readpage(sbi, page, addr, READ_SYNC))
1477 			goto out;
1478 
1479 		rn = (struct f2fs_node *)page_address(page);
1480 		sum_entry->nid = rn->footer.nid;
1481 		sum_entry->version = 0;
1482 		sum_entry->ofs_in_node = 0;
1483 		addr++;
1484 
1485 		/*
1486 		 * In order to read next node page,
1487 		 * we must clear PageUptodate flag.
1488 		 */
1489 		ClearPageUptodate(page);
1490 	}
1491 out:
1492 	unlock_page(page);
1493 	__free_pages(page, 0);
1494 	return 0;
1495 }
1496 
1497 static bool flush_nats_in_journal(struct f2fs_sb_info *sbi)
1498 {
1499 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1500 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1501 	struct f2fs_summary_block *sum = curseg->sum_blk;
1502 	int i;
1503 
1504 	mutex_lock(&curseg->curseg_mutex);
1505 
1506 	if (nats_in_cursum(sum) < NAT_JOURNAL_ENTRIES) {
1507 		mutex_unlock(&curseg->curseg_mutex);
1508 		return false;
1509 	}
1510 
1511 	for (i = 0; i < nats_in_cursum(sum); i++) {
1512 		struct nat_entry *ne;
1513 		struct f2fs_nat_entry raw_ne;
1514 		nid_t nid = le32_to_cpu(nid_in_journal(sum, i));
1515 
1516 		raw_ne = nat_in_journal(sum, i);
1517 retry:
1518 		write_lock(&nm_i->nat_tree_lock);
1519 		ne = __lookup_nat_cache(nm_i, nid);
1520 		if (ne) {
1521 			__set_nat_cache_dirty(nm_i, ne);
1522 			write_unlock(&nm_i->nat_tree_lock);
1523 			continue;
1524 		}
1525 		ne = grab_nat_entry(nm_i, nid);
1526 		if (!ne) {
1527 			write_unlock(&nm_i->nat_tree_lock);
1528 			goto retry;
1529 		}
1530 		nat_set_blkaddr(ne, le32_to_cpu(raw_ne.block_addr));
1531 		nat_set_ino(ne, le32_to_cpu(raw_ne.ino));
1532 		nat_set_version(ne, raw_ne.version);
1533 		__set_nat_cache_dirty(nm_i, ne);
1534 		write_unlock(&nm_i->nat_tree_lock);
1535 	}
1536 	update_nats_in_cursum(sum, -i);
1537 	mutex_unlock(&curseg->curseg_mutex);
1538 	return true;
1539 }
1540 
1541 /*
1542  * This function is called during the checkpointing process.
1543  */
1544 void flush_nat_entries(struct f2fs_sb_info *sbi)
1545 {
1546 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1547 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1548 	struct f2fs_summary_block *sum = curseg->sum_blk;
1549 	struct list_head *cur, *n;
1550 	struct page *page = NULL;
1551 	struct f2fs_nat_block *nat_blk = NULL;
1552 	nid_t start_nid = 0, end_nid = 0;
1553 	bool flushed;
1554 
1555 	flushed = flush_nats_in_journal(sbi);
1556 
1557 	if (!flushed)
1558 		mutex_lock(&curseg->curseg_mutex);
1559 
1560 	/* 1) flush dirty nat caches */
1561 	list_for_each_safe(cur, n, &nm_i->dirty_nat_entries) {
1562 		struct nat_entry *ne;
1563 		nid_t nid;
1564 		struct f2fs_nat_entry raw_ne;
1565 		int offset = -1;
1566 		block_t new_blkaddr;
1567 
1568 		ne = list_entry(cur, struct nat_entry, list);
1569 		nid = nat_get_nid(ne);
1570 
1571 		if (nat_get_blkaddr(ne) == NEW_ADDR)
1572 			continue;
1573 		if (flushed)
1574 			goto to_nat_page;
1575 
1576 		/* if there is room for nat enries in curseg->sumpage */
1577 		offset = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 1);
1578 		if (offset >= 0) {
1579 			raw_ne = nat_in_journal(sum, offset);
1580 			goto flush_now;
1581 		}
1582 to_nat_page:
1583 		if (!page || (start_nid > nid || nid > end_nid)) {
1584 			if (page) {
1585 				f2fs_put_page(page, 1);
1586 				page = NULL;
1587 			}
1588 			start_nid = START_NID(nid);
1589 			end_nid = start_nid + NAT_ENTRY_PER_BLOCK - 1;
1590 
1591 			/*
1592 			 * get nat block with dirty flag, increased reference
1593 			 * count, mapped and lock
1594 			 */
1595 			page = get_next_nat_page(sbi, start_nid);
1596 			nat_blk = page_address(page);
1597 		}
1598 
1599 		BUG_ON(!nat_blk);
1600 		raw_ne = nat_blk->entries[nid - start_nid];
1601 flush_now:
1602 		new_blkaddr = nat_get_blkaddr(ne);
1603 
1604 		raw_ne.ino = cpu_to_le32(nat_get_ino(ne));
1605 		raw_ne.block_addr = cpu_to_le32(new_blkaddr);
1606 		raw_ne.version = nat_get_version(ne);
1607 
1608 		if (offset < 0) {
1609 			nat_blk->entries[nid - start_nid] = raw_ne;
1610 		} else {
1611 			nat_in_journal(sum, offset) = raw_ne;
1612 			nid_in_journal(sum, offset) = cpu_to_le32(nid);
1613 		}
1614 
1615 		if (nat_get_blkaddr(ne) == NULL_ADDR) {
1616 			write_lock(&nm_i->nat_tree_lock);
1617 			__del_from_nat_cache(nm_i, ne);
1618 			write_unlock(&nm_i->nat_tree_lock);
1619 
1620 			/* We can reuse this freed nid at this point */
1621 			add_free_nid(NM_I(sbi), nid);
1622 		} else {
1623 			write_lock(&nm_i->nat_tree_lock);
1624 			__clear_nat_cache_dirty(nm_i, ne);
1625 			ne->checkpointed = true;
1626 			write_unlock(&nm_i->nat_tree_lock);
1627 		}
1628 	}
1629 	if (!flushed)
1630 		mutex_unlock(&curseg->curseg_mutex);
1631 	f2fs_put_page(page, 1);
1632 
1633 	/* 2) shrink nat caches if necessary */
1634 	try_to_free_nats(sbi, nm_i->nat_cnt - NM_WOUT_THRESHOLD);
1635 }
1636 
1637 static int init_node_manager(struct f2fs_sb_info *sbi)
1638 {
1639 	struct f2fs_super_block *sb_raw = F2FS_RAW_SUPER(sbi);
1640 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1641 	unsigned char *version_bitmap;
1642 	unsigned int nat_segs, nat_blocks;
1643 
1644 	nm_i->nat_blkaddr = le32_to_cpu(sb_raw->nat_blkaddr);
1645 
1646 	/* segment_count_nat includes pair segment so divide to 2. */
1647 	nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
1648 	nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
1649 	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
1650 	nm_i->fcnt = 0;
1651 	nm_i->nat_cnt = 0;
1652 
1653 	INIT_LIST_HEAD(&nm_i->free_nid_list);
1654 	INIT_RADIX_TREE(&nm_i->nat_root, GFP_ATOMIC);
1655 	INIT_LIST_HEAD(&nm_i->nat_entries);
1656 	INIT_LIST_HEAD(&nm_i->dirty_nat_entries);
1657 
1658 	mutex_init(&nm_i->build_lock);
1659 	spin_lock_init(&nm_i->free_nid_list_lock);
1660 	rwlock_init(&nm_i->nat_tree_lock);
1661 
1662 	nm_i->bitmap_size = __bitmap_size(sbi, NAT_BITMAP);
1663 	nm_i->init_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
1664 	nm_i->next_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
1665 
1666 	nm_i->nat_bitmap = kzalloc(nm_i->bitmap_size, GFP_KERNEL);
1667 	if (!nm_i->nat_bitmap)
1668 		return -ENOMEM;
1669 	version_bitmap = __bitmap_ptr(sbi, NAT_BITMAP);
1670 	if (!version_bitmap)
1671 		return -EFAULT;
1672 
1673 	/* copy version bitmap */
1674 	memcpy(nm_i->nat_bitmap, version_bitmap, nm_i->bitmap_size);
1675 	return 0;
1676 }
1677 
1678 int build_node_manager(struct f2fs_sb_info *sbi)
1679 {
1680 	int err;
1681 
1682 	sbi->nm_info = kzalloc(sizeof(struct f2fs_nm_info), GFP_KERNEL);
1683 	if (!sbi->nm_info)
1684 		return -ENOMEM;
1685 
1686 	err = init_node_manager(sbi);
1687 	if (err)
1688 		return err;
1689 
1690 	build_free_nids(sbi);
1691 	return 0;
1692 }
1693 
1694 void destroy_node_manager(struct f2fs_sb_info *sbi)
1695 {
1696 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1697 	struct free_nid *i, *next_i;
1698 	struct nat_entry *natvec[NATVEC_SIZE];
1699 	nid_t nid = 0;
1700 	unsigned int found;
1701 
1702 	if (!nm_i)
1703 		return;
1704 
1705 	/* destroy free nid list */
1706 	spin_lock(&nm_i->free_nid_list_lock);
1707 	list_for_each_entry_safe(i, next_i, &nm_i->free_nid_list, list) {
1708 		BUG_ON(i->state == NID_ALLOC);
1709 		__del_from_free_nid_list(i);
1710 		nm_i->fcnt--;
1711 	}
1712 	BUG_ON(nm_i->fcnt);
1713 	spin_unlock(&nm_i->free_nid_list_lock);
1714 
1715 	/* destroy nat cache */
1716 	write_lock(&nm_i->nat_tree_lock);
1717 	while ((found = __gang_lookup_nat_cache(nm_i,
1718 					nid, NATVEC_SIZE, natvec))) {
1719 		unsigned idx;
1720 		for (idx = 0; idx < found; idx++) {
1721 			struct nat_entry *e = natvec[idx];
1722 			nid = nat_get_nid(e) + 1;
1723 			__del_from_nat_cache(nm_i, e);
1724 		}
1725 	}
1726 	BUG_ON(nm_i->nat_cnt);
1727 	write_unlock(&nm_i->nat_tree_lock);
1728 
1729 	kfree(nm_i->nat_bitmap);
1730 	sbi->nm_info = NULL;
1731 	kfree(nm_i);
1732 }
1733 
1734 int __init create_node_manager_caches(void)
1735 {
1736 	nat_entry_slab = f2fs_kmem_cache_create("nat_entry",
1737 			sizeof(struct nat_entry), NULL);
1738 	if (!nat_entry_slab)
1739 		return -ENOMEM;
1740 
1741 	free_nid_slab = f2fs_kmem_cache_create("free_nid",
1742 			sizeof(struct free_nid), NULL);
1743 	if (!free_nid_slab) {
1744 		kmem_cache_destroy(nat_entry_slab);
1745 		return -ENOMEM;
1746 	}
1747 	return 0;
1748 }
1749 
1750 void destroy_node_manager_caches(void)
1751 {
1752 	kmem_cache_destroy(free_nid_slab);
1753 	kmem_cache_destroy(nat_entry_slab);
1754 }
1755