xref: /openbmc/linux/fs/f2fs/node.c (revision 6aeedba20e82150757f2dd5b896f0e09491a987c)
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 		level = 0;
325 		goto got;
326 	}
327 	block -= direct_index;
328 	if (block < direct_blks) {
329 		offset[n++] = NODE_DIR1_BLOCK;
330 		noffset[n] = 1;
331 		offset[n++] = block;
332 		level = 1;
333 		goto got;
334 	}
335 	block -= direct_blks;
336 	if (block < direct_blks) {
337 		offset[n++] = NODE_DIR2_BLOCK;
338 		noffset[n] = 2;
339 		offset[n++] = block;
340 		level = 1;
341 		goto got;
342 	}
343 	block -= direct_blks;
344 	if (block < indirect_blks) {
345 		offset[n++] = NODE_IND1_BLOCK;
346 		noffset[n] = 3;
347 		offset[n++] = block / direct_blks;
348 		noffset[n] = 4 + offset[n - 1];
349 		offset[n++] = block % direct_blks;
350 		level = 2;
351 		goto got;
352 	}
353 	block -= indirect_blks;
354 	if (block < indirect_blks) {
355 		offset[n++] = NODE_IND2_BLOCK;
356 		noffset[n] = 4 + dptrs_per_blk;
357 		offset[n++] = block / direct_blks;
358 		noffset[n] = 5 + dptrs_per_blk + offset[n - 1];
359 		offset[n++] = block % direct_blks;
360 		level = 2;
361 		goto got;
362 	}
363 	block -= indirect_blks;
364 	if (block < dindirect_blks) {
365 		offset[n++] = NODE_DIND_BLOCK;
366 		noffset[n] = 5 + (dptrs_per_blk * 2);
367 		offset[n++] = block / indirect_blks;
368 		noffset[n] = 6 + (dptrs_per_blk * 2) +
369 			      offset[n - 1] * (dptrs_per_blk + 1);
370 		offset[n++] = (block / direct_blks) % dptrs_per_blk;
371 		noffset[n] = 7 + (dptrs_per_blk * 2) +
372 			      offset[n - 2] * (dptrs_per_blk + 1) +
373 			      offset[n - 1];
374 		offset[n++] = block % direct_blks;
375 		level = 3;
376 		goto got;
377 	} else {
378 		BUG();
379 	}
380 got:
381 	return level;
382 }
383 
384 /*
385  * Caller should call f2fs_put_dnode(dn).
386  */
387 int get_dnode_of_data(struct dnode_of_data *dn, pgoff_t index, int ro)
388 {
389 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
390 	struct page *npage[4];
391 	struct page *parent;
392 	int offset[4];
393 	unsigned int noffset[4];
394 	nid_t nids[4];
395 	int level, i;
396 	int err = 0;
397 
398 	level = get_node_path(index, offset, noffset);
399 
400 	nids[0] = dn->inode->i_ino;
401 	npage[0] = get_node_page(sbi, nids[0]);
402 	if (IS_ERR(npage[0]))
403 		return PTR_ERR(npage[0]);
404 
405 	parent = npage[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] && !ro) {
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 (ro && 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 	page = find_get_page(mapping, nid);
924 	if (page && PageUptodate(page))
925 		goto page_hit;
926 	f2fs_put_page(page, 0);
927 
928 repeat:
929 	page = grab_cache_page(mapping, nid);
930 	if (!page)
931 		return ERR_PTR(-ENOMEM);
932 
933 	err = read_node_page(page, READA);
934 	if (err) {
935 		f2fs_put_page(page, 1);
936 		return ERR_PTR(err);
937 	}
938 
939 	/* Then, try readahead for siblings of the desired node */
940 	end = start + MAX_RA_NODE;
941 	end = min(end, NIDS_PER_BLOCK);
942 	for (i = start + 1; i < end; i++) {
943 		nid = get_nid(parent, i, false);
944 		if (!nid)
945 			continue;
946 		ra_node_page(sbi, nid);
947 	}
948 
949 page_hit:
950 	lock_page(page);
951 	if (PageError(page)) {
952 		f2fs_put_page(page, 1);
953 		return ERR_PTR(-EIO);
954 	}
955 
956 	/* Has the page been truncated? */
957 	if (page->mapping != mapping) {
958 		f2fs_put_page(page, 1);
959 		goto repeat;
960 	}
961 	return page;
962 }
963 
964 void sync_inode_page(struct dnode_of_data *dn)
965 {
966 	if (IS_INODE(dn->node_page) || dn->inode_page == dn->node_page) {
967 		update_inode(dn->inode, dn->node_page);
968 	} else if (dn->inode_page) {
969 		if (!dn->inode_page_locked)
970 			lock_page(dn->inode_page);
971 		update_inode(dn->inode, dn->inode_page);
972 		if (!dn->inode_page_locked)
973 			unlock_page(dn->inode_page);
974 	} else {
975 		f2fs_write_inode(dn->inode, NULL);
976 	}
977 }
978 
979 int sync_node_pages(struct f2fs_sb_info *sbi, nid_t ino,
980 					struct writeback_control *wbc)
981 {
982 	struct address_space *mapping = sbi->node_inode->i_mapping;
983 	pgoff_t index, end;
984 	struct pagevec pvec;
985 	int step = ino ? 2 : 0;
986 	int nwritten = 0, wrote = 0;
987 
988 	pagevec_init(&pvec, 0);
989 
990 next_step:
991 	index = 0;
992 	end = LONG_MAX;
993 
994 	while (index <= end) {
995 		int i, nr_pages;
996 		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
997 				PAGECACHE_TAG_DIRTY,
998 				min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
999 		if (nr_pages == 0)
1000 			break;
1001 
1002 		for (i = 0; i < nr_pages; i++) {
1003 			struct page *page = pvec.pages[i];
1004 
1005 			/*
1006 			 * flushing sequence with step:
1007 			 * 0. indirect nodes
1008 			 * 1. dentry dnodes
1009 			 * 2. file dnodes
1010 			 */
1011 			if (step == 0 && IS_DNODE(page))
1012 				continue;
1013 			if (step == 1 && (!IS_DNODE(page) ||
1014 						is_cold_node(page)))
1015 				continue;
1016 			if (step == 2 && (!IS_DNODE(page) ||
1017 						!is_cold_node(page)))
1018 				continue;
1019 
1020 			/*
1021 			 * If an fsync mode,
1022 			 * we should not skip writing node pages.
1023 			 */
1024 			if (ino && ino_of_node(page) == ino)
1025 				lock_page(page);
1026 			else if (!trylock_page(page))
1027 				continue;
1028 
1029 			if (unlikely(page->mapping != mapping)) {
1030 continue_unlock:
1031 				unlock_page(page);
1032 				continue;
1033 			}
1034 			if (ino && ino_of_node(page) != ino)
1035 				goto continue_unlock;
1036 
1037 			if (!PageDirty(page)) {
1038 				/* someone wrote it for us */
1039 				goto continue_unlock;
1040 			}
1041 
1042 			if (!clear_page_dirty_for_io(page))
1043 				goto continue_unlock;
1044 
1045 			/* called by fsync() */
1046 			if (ino && IS_DNODE(page)) {
1047 				int mark = !is_checkpointed_node(sbi, ino);
1048 				set_fsync_mark(page, 1);
1049 				if (IS_INODE(page))
1050 					set_dentry_mark(page, mark);
1051 				nwritten++;
1052 			} else {
1053 				set_fsync_mark(page, 0);
1054 				set_dentry_mark(page, 0);
1055 			}
1056 			mapping->a_ops->writepage(page, wbc);
1057 			wrote++;
1058 
1059 			if (--wbc->nr_to_write == 0)
1060 				break;
1061 		}
1062 		pagevec_release(&pvec);
1063 		cond_resched();
1064 
1065 		if (wbc->nr_to_write == 0) {
1066 			step = 2;
1067 			break;
1068 		}
1069 	}
1070 
1071 	if (step < 2) {
1072 		step++;
1073 		goto next_step;
1074 	}
1075 
1076 	if (wrote)
1077 		f2fs_submit_bio(sbi, NODE, wbc->sync_mode == WB_SYNC_ALL);
1078 
1079 	return nwritten;
1080 }
1081 
1082 static int f2fs_write_node_page(struct page *page,
1083 				struct writeback_control *wbc)
1084 {
1085 	struct f2fs_sb_info *sbi = F2FS_SB(page->mapping->host->i_sb);
1086 	nid_t nid;
1087 	block_t new_addr;
1088 	struct node_info ni;
1089 
1090 	if (wbc->for_reclaim) {
1091 		dec_page_count(sbi, F2FS_DIRTY_NODES);
1092 		wbc->pages_skipped++;
1093 		set_page_dirty(page);
1094 		return AOP_WRITEPAGE_ACTIVATE;
1095 	}
1096 
1097 	wait_on_page_writeback(page);
1098 
1099 	mutex_lock_op(sbi, NODE_WRITE);
1100 
1101 	/* get old block addr of this node page */
1102 	nid = nid_of_node(page);
1103 	BUG_ON(page->index != nid);
1104 
1105 	get_node_info(sbi, nid, &ni);
1106 
1107 	/* This page is already truncated */
1108 	if (ni.blk_addr == NULL_ADDR)
1109 		return 0;
1110 
1111 	set_page_writeback(page);
1112 
1113 	/* insert node offset */
1114 	write_node_page(sbi, page, nid, ni.blk_addr, &new_addr);
1115 	set_node_addr(sbi, &ni, new_addr);
1116 	dec_page_count(sbi, F2FS_DIRTY_NODES);
1117 
1118 	mutex_unlock_op(sbi, NODE_WRITE);
1119 	unlock_page(page);
1120 	return 0;
1121 }
1122 
1123 /*
1124  * It is very important to gather dirty pages and write at once, so that we can
1125  * submit a big bio without interfering other data writes.
1126  * Be default, 512 pages (2MB), a segment size, is quite reasonable.
1127  */
1128 #define COLLECT_DIRTY_NODES	512
1129 static int f2fs_write_node_pages(struct address_space *mapping,
1130 			    struct writeback_control *wbc)
1131 {
1132 	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1133 	struct block_device *bdev = sbi->sb->s_bdev;
1134 	long nr_to_write = wbc->nr_to_write;
1135 
1136 	/* First check balancing cached NAT entries */
1137 	if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) {
1138 		write_checkpoint(sbi, false);
1139 		return 0;
1140 	}
1141 
1142 	/* collect a number of dirty node pages and write together */
1143 	if (get_pages(sbi, F2FS_DIRTY_NODES) < COLLECT_DIRTY_NODES)
1144 		return 0;
1145 
1146 	/* if mounting is failed, skip writing node pages */
1147 	wbc->nr_to_write = bio_get_nr_vecs(bdev);
1148 	sync_node_pages(sbi, 0, wbc);
1149 	wbc->nr_to_write = nr_to_write -
1150 		(bio_get_nr_vecs(bdev) - wbc->nr_to_write);
1151 	return 0;
1152 }
1153 
1154 static int f2fs_set_node_page_dirty(struct page *page)
1155 {
1156 	struct address_space *mapping = page->mapping;
1157 	struct f2fs_sb_info *sbi = F2FS_SB(mapping->host->i_sb);
1158 
1159 	SetPageUptodate(page);
1160 	if (!PageDirty(page)) {
1161 		__set_page_dirty_nobuffers(page);
1162 		inc_page_count(sbi, F2FS_DIRTY_NODES);
1163 		SetPagePrivate(page);
1164 		return 1;
1165 	}
1166 	return 0;
1167 }
1168 
1169 static void f2fs_invalidate_node_page(struct page *page, unsigned long offset)
1170 {
1171 	struct inode *inode = page->mapping->host;
1172 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
1173 	if (PageDirty(page))
1174 		dec_page_count(sbi, F2FS_DIRTY_NODES);
1175 	ClearPagePrivate(page);
1176 }
1177 
1178 static int f2fs_release_node_page(struct page *page, gfp_t wait)
1179 {
1180 	ClearPagePrivate(page);
1181 	return 0;
1182 }
1183 
1184 /*
1185  * Structure of the f2fs node operations
1186  */
1187 const struct address_space_operations f2fs_node_aops = {
1188 	.writepage	= f2fs_write_node_page,
1189 	.writepages	= f2fs_write_node_pages,
1190 	.set_page_dirty	= f2fs_set_node_page_dirty,
1191 	.invalidatepage	= f2fs_invalidate_node_page,
1192 	.releasepage	= f2fs_release_node_page,
1193 };
1194 
1195 static struct free_nid *__lookup_free_nid_list(nid_t n, struct list_head *head)
1196 {
1197 	struct list_head *this;
1198 	struct free_nid *i = NULL;
1199 	list_for_each(this, head) {
1200 		i = list_entry(this, struct free_nid, list);
1201 		if (i->nid == n)
1202 			break;
1203 		i = NULL;
1204 	}
1205 	return i;
1206 }
1207 
1208 static void __del_from_free_nid_list(struct free_nid *i)
1209 {
1210 	list_del(&i->list);
1211 	kmem_cache_free(free_nid_slab, i);
1212 }
1213 
1214 static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
1215 {
1216 	struct free_nid *i;
1217 
1218 	if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
1219 		return 0;
1220 retry:
1221 	i = kmem_cache_alloc(free_nid_slab, GFP_NOFS);
1222 	if (!i) {
1223 		cond_resched();
1224 		goto retry;
1225 	}
1226 	i->nid = nid;
1227 	i->state = NID_NEW;
1228 
1229 	spin_lock(&nm_i->free_nid_list_lock);
1230 	if (__lookup_free_nid_list(nid, &nm_i->free_nid_list)) {
1231 		spin_unlock(&nm_i->free_nid_list_lock);
1232 		kmem_cache_free(free_nid_slab, i);
1233 		return 0;
1234 	}
1235 	list_add_tail(&i->list, &nm_i->free_nid_list);
1236 	nm_i->fcnt++;
1237 	spin_unlock(&nm_i->free_nid_list_lock);
1238 	return 1;
1239 }
1240 
1241 static void remove_free_nid(struct f2fs_nm_info *nm_i, nid_t nid)
1242 {
1243 	struct free_nid *i;
1244 	spin_lock(&nm_i->free_nid_list_lock);
1245 	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
1246 	if (i && i->state == NID_NEW) {
1247 		__del_from_free_nid_list(i);
1248 		nm_i->fcnt--;
1249 	}
1250 	spin_unlock(&nm_i->free_nid_list_lock);
1251 }
1252 
1253 static int scan_nat_page(struct f2fs_nm_info *nm_i,
1254 			struct page *nat_page, nid_t start_nid)
1255 {
1256 	struct f2fs_nat_block *nat_blk = page_address(nat_page);
1257 	block_t blk_addr;
1258 	int fcnt = 0;
1259 	int i;
1260 
1261 	/* 0 nid should not be used */
1262 	if (start_nid == 0)
1263 		++start_nid;
1264 
1265 	i = start_nid % NAT_ENTRY_PER_BLOCK;
1266 
1267 	for (; i < NAT_ENTRY_PER_BLOCK; i++, start_nid++) {
1268 		blk_addr  = le32_to_cpu(nat_blk->entries[i].block_addr);
1269 		BUG_ON(blk_addr == NEW_ADDR);
1270 		if (blk_addr == NULL_ADDR)
1271 			fcnt += add_free_nid(nm_i, start_nid);
1272 	}
1273 	return fcnt;
1274 }
1275 
1276 static void build_free_nids(struct f2fs_sb_info *sbi)
1277 {
1278 	struct free_nid *fnid, *next_fnid;
1279 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1280 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1281 	struct f2fs_summary_block *sum = curseg->sum_blk;
1282 	nid_t nid = 0;
1283 	bool is_cycled = false;
1284 	int fcnt = 0;
1285 	int i;
1286 
1287 	nid = nm_i->next_scan_nid;
1288 	nm_i->init_scan_nid = nid;
1289 
1290 	ra_nat_pages(sbi, nid);
1291 
1292 	while (1) {
1293 		struct page *page = get_current_nat_page(sbi, nid);
1294 
1295 		fcnt += scan_nat_page(nm_i, page, nid);
1296 		f2fs_put_page(page, 1);
1297 
1298 		nid += (NAT_ENTRY_PER_BLOCK - (nid % NAT_ENTRY_PER_BLOCK));
1299 
1300 		if (nid >= nm_i->max_nid) {
1301 			nid = 0;
1302 			is_cycled = true;
1303 		}
1304 		if (fcnt > MAX_FREE_NIDS)
1305 			break;
1306 		if (is_cycled && nm_i->init_scan_nid <= nid)
1307 			break;
1308 	}
1309 
1310 	nm_i->next_scan_nid = nid;
1311 
1312 	/* find free nids from current sum_pages */
1313 	mutex_lock(&curseg->curseg_mutex);
1314 	for (i = 0; i < nats_in_cursum(sum); i++) {
1315 		block_t addr = le32_to_cpu(nat_in_journal(sum, i).block_addr);
1316 		nid = le32_to_cpu(nid_in_journal(sum, i));
1317 		if (addr == NULL_ADDR)
1318 			add_free_nid(nm_i, nid);
1319 		else
1320 			remove_free_nid(nm_i, nid);
1321 	}
1322 	mutex_unlock(&curseg->curseg_mutex);
1323 
1324 	/* remove the free nids from current allocated nids */
1325 	list_for_each_entry_safe(fnid, next_fnid, &nm_i->free_nid_list, list) {
1326 		struct nat_entry *ne;
1327 
1328 		read_lock(&nm_i->nat_tree_lock);
1329 		ne = __lookup_nat_cache(nm_i, fnid->nid);
1330 		if (ne && nat_get_blkaddr(ne) != NULL_ADDR)
1331 			remove_free_nid(nm_i, fnid->nid);
1332 		read_unlock(&nm_i->nat_tree_lock);
1333 	}
1334 }
1335 
1336 /*
1337  * If this function returns success, caller can obtain a new nid
1338  * from second parameter of this function.
1339  * The returned nid could be used ino as well as nid when inode is created.
1340  */
1341 bool alloc_nid(struct f2fs_sb_info *sbi, nid_t *nid)
1342 {
1343 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1344 	struct free_nid *i = NULL;
1345 	struct list_head *this;
1346 retry:
1347 	mutex_lock(&nm_i->build_lock);
1348 	if (!nm_i->fcnt) {
1349 		/* scan NAT in order to build free nid list */
1350 		build_free_nids(sbi);
1351 		if (!nm_i->fcnt) {
1352 			mutex_unlock(&nm_i->build_lock);
1353 			return false;
1354 		}
1355 	}
1356 	mutex_unlock(&nm_i->build_lock);
1357 
1358 	/*
1359 	 * We check fcnt again since previous check is racy as
1360 	 * we didn't hold free_nid_list_lock. So other thread
1361 	 * could consume all of free nids.
1362 	 */
1363 	spin_lock(&nm_i->free_nid_list_lock);
1364 	if (!nm_i->fcnt) {
1365 		spin_unlock(&nm_i->free_nid_list_lock);
1366 		goto retry;
1367 	}
1368 
1369 	BUG_ON(list_empty(&nm_i->free_nid_list));
1370 	list_for_each(this, &nm_i->free_nid_list) {
1371 		i = list_entry(this, struct free_nid, list);
1372 		if (i->state == NID_NEW)
1373 			break;
1374 	}
1375 
1376 	BUG_ON(i->state != NID_NEW);
1377 	*nid = i->nid;
1378 	i->state = NID_ALLOC;
1379 	nm_i->fcnt--;
1380 	spin_unlock(&nm_i->free_nid_list_lock);
1381 	return true;
1382 }
1383 
1384 /*
1385  * alloc_nid() should be called prior to this function.
1386  */
1387 void alloc_nid_done(struct f2fs_sb_info *sbi, nid_t nid)
1388 {
1389 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1390 	struct free_nid *i;
1391 
1392 	spin_lock(&nm_i->free_nid_list_lock);
1393 	i = __lookup_free_nid_list(nid, &nm_i->free_nid_list);
1394 	if (i) {
1395 		BUG_ON(i->state != NID_ALLOC);
1396 		__del_from_free_nid_list(i);
1397 	}
1398 	spin_unlock(&nm_i->free_nid_list_lock);
1399 }
1400 
1401 /*
1402  * alloc_nid() should be called prior to this function.
1403  */
1404 void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
1405 {
1406 	alloc_nid_done(sbi, nid);
1407 	add_free_nid(NM_I(sbi), nid);
1408 }
1409 
1410 void recover_node_page(struct f2fs_sb_info *sbi, struct page *page,
1411 		struct f2fs_summary *sum, struct node_info *ni,
1412 		block_t new_blkaddr)
1413 {
1414 	rewrite_node_page(sbi, page, sum, ni->blk_addr, new_blkaddr);
1415 	set_node_addr(sbi, ni, new_blkaddr);
1416 	clear_node_page_dirty(page);
1417 }
1418 
1419 int recover_inode_page(struct f2fs_sb_info *sbi, struct page *page)
1420 {
1421 	struct address_space *mapping = sbi->node_inode->i_mapping;
1422 	struct f2fs_node *src, *dst;
1423 	nid_t ino = ino_of_node(page);
1424 	struct node_info old_ni, new_ni;
1425 	struct page *ipage;
1426 
1427 	ipage = grab_cache_page(mapping, ino);
1428 	if (!ipage)
1429 		return -ENOMEM;
1430 
1431 	/* Should not use this inode  from free nid list */
1432 	remove_free_nid(NM_I(sbi), ino);
1433 
1434 	get_node_info(sbi, ino, &old_ni);
1435 	SetPageUptodate(ipage);
1436 	fill_node_footer(ipage, ino, ino, 0, true);
1437 
1438 	src = (struct f2fs_node *)page_address(page);
1439 	dst = (struct f2fs_node *)page_address(ipage);
1440 
1441 	memcpy(dst, src, (unsigned long)&src->i.i_ext - (unsigned long)&src->i);
1442 	dst->i.i_size = 0;
1443 	dst->i.i_blocks = cpu_to_le64(1);
1444 	dst->i.i_links = cpu_to_le32(1);
1445 	dst->i.i_xattr_nid = 0;
1446 
1447 	new_ni = old_ni;
1448 	new_ni.ino = ino;
1449 
1450 	set_node_addr(sbi, &new_ni, NEW_ADDR);
1451 	inc_valid_inode_count(sbi);
1452 
1453 	f2fs_put_page(ipage, 1);
1454 	return 0;
1455 }
1456 
1457 int restore_node_summary(struct f2fs_sb_info *sbi,
1458 			unsigned int segno, struct f2fs_summary_block *sum)
1459 {
1460 	struct f2fs_node *rn;
1461 	struct f2fs_summary *sum_entry;
1462 	struct page *page;
1463 	block_t addr;
1464 	int i, last_offset;
1465 
1466 	/* alloc temporal page for read node */
1467 	page = alloc_page(GFP_NOFS | __GFP_ZERO);
1468 	if (IS_ERR(page))
1469 		return PTR_ERR(page);
1470 	lock_page(page);
1471 
1472 	/* scan the node segment */
1473 	last_offset = sbi->blocks_per_seg;
1474 	addr = START_BLOCK(sbi, segno);
1475 	sum_entry = &sum->entries[0];
1476 
1477 	for (i = 0; i < last_offset; i++, sum_entry++) {
1478 		if (f2fs_readpage(sbi, page, addr, READ_SYNC))
1479 			goto out;
1480 
1481 		rn = (struct f2fs_node *)page_address(page);
1482 		sum_entry->nid = rn->footer.nid;
1483 		sum_entry->version = 0;
1484 		sum_entry->ofs_in_node = 0;
1485 		addr++;
1486 
1487 		/*
1488 		 * In order to read next node page,
1489 		 * we must clear PageUptodate flag.
1490 		 */
1491 		ClearPageUptodate(page);
1492 	}
1493 out:
1494 	unlock_page(page);
1495 	__free_pages(page, 0);
1496 	return 0;
1497 }
1498 
1499 static bool flush_nats_in_journal(struct f2fs_sb_info *sbi)
1500 {
1501 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1502 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1503 	struct f2fs_summary_block *sum = curseg->sum_blk;
1504 	int i;
1505 
1506 	mutex_lock(&curseg->curseg_mutex);
1507 
1508 	if (nats_in_cursum(sum) < NAT_JOURNAL_ENTRIES) {
1509 		mutex_unlock(&curseg->curseg_mutex);
1510 		return false;
1511 	}
1512 
1513 	for (i = 0; i < nats_in_cursum(sum); i++) {
1514 		struct nat_entry *ne;
1515 		struct f2fs_nat_entry raw_ne;
1516 		nid_t nid = le32_to_cpu(nid_in_journal(sum, i));
1517 
1518 		raw_ne = nat_in_journal(sum, i);
1519 retry:
1520 		write_lock(&nm_i->nat_tree_lock);
1521 		ne = __lookup_nat_cache(nm_i, nid);
1522 		if (ne) {
1523 			__set_nat_cache_dirty(nm_i, ne);
1524 			write_unlock(&nm_i->nat_tree_lock);
1525 			continue;
1526 		}
1527 		ne = grab_nat_entry(nm_i, nid);
1528 		if (!ne) {
1529 			write_unlock(&nm_i->nat_tree_lock);
1530 			goto retry;
1531 		}
1532 		nat_set_blkaddr(ne, le32_to_cpu(raw_ne.block_addr));
1533 		nat_set_ino(ne, le32_to_cpu(raw_ne.ino));
1534 		nat_set_version(ne, raw_ne.version);
1535 		__set_nat_cache_dirty(nm_i, ne);
1536 		write_unlock(&nm_i->nat_tree_lock);
1537 	}
1538 	update_nats_in_cursum(sum, -i);
1539 	mutex_unlock(&curseg->curseg_mutex);
1540 	return true;
1541 }
1542 
1543 /*
1544  * This function is called during the checkpointing process.
1545  */
1546 void flush_nat_entries(struct f2fs_sb_info *sbi)
1547 {
1548 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1549 	struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_HOT_DATA);
1550 	struct f2fs_summary_block *sum = curseg->sum_blk;
1551 	struct list_head *cur, *n;
1552 	struct page *page = NULL;
1553 	struct f2fs_nat_block *nat_blk = NULL;
1554 	nid_t start_nid = 0, end_nid = 0;
1555 	bool flushed;
1556 
1557 	flushed = flush_nats_in_journal(sbi);
1558 
1559 	if (!flushed)
1560 		mutex_lock(&curseg->curseg_mutex);
1561 
1562 	/* 1) flush dirty nat caches */
1563 	list_for_each_safe(cur, n, &nm_i->dirty_nat_entries) {
1564 		struct nat_entry *ne;
1565 		nid_t nid;
1566 		struct f2fs_nat_entry raw_ne;
1567 		int offset = -1;
1568 		block_t new_blkaddr;
1569 
1570 		ne = list_entry(cur, struct nat_entry, list);
1571 		nid = nat_get_nid(ne);
1572 
1573 		if (nat_get_blkaddr(ne) == NEW_ADDR)
1574 			continue;
1575 		if (flushed)
1576 			goto to_nat_page;
1577 
1578 		/* if there is room for nat enries in curseg->sumpage */
1579 		offset = lookup_journal_in_cursum(sum, NAT_JOURNAL, nid, 1);
1580 		if (offset >= 0) {
1581 			raw_ne = nat_in_journal(sum, offset);
1582 			goto flush_now;
1583 		}
1584 to_nat_page:
1585 		if (!page || (start_nid > nid || nid > end_nid)) {
1586 			if (page) {
1587 				f2fs_put_page(page, 1);
1588 				page = NULL;
1589 			}
1590 			start_nid = START_NID(nid);
1591 			end_nid = start_nid + NAT_ENTRY_PER_BLOCK - 1;
1592 
1593 			/*
1594 			 * get nat block with dirty flag, increased reference
1595 			 * count, mapped and lock
1596 			 */
1597 			page = get_next_nat_page(sbi, start_nid);
1598 			nat_blk = page_address(page);
1599 		}
1600 
1601 		BUG_ON(!nat_blk);
1602 		raw_ne = nat_blk->entries[nid - start_nid];
1603 flush_now:
1604 		new_blkaddr = nat_get_blkaddr(ne);
1605 
1606 		raw_ne.ino = cpu_to_le32(nat_get_ino(ne));
1607 		raw_ne.block_addr = cpu_to_le32(new_blkaddr);
1608 		raw_ne.version = nat_get_version(ne);
1609 
1610 		if (offset < 0) {
1611 			nat_blk->entries[nid - start_nid] = raw_ne;
1612 		} else {
1613 			nat_in_journal(sum, offset) = raw_ne;
1614 			nid_in_journal(sum, offset) = cpu_to_le32(nid);
1615 		}
1616 
1617 		if (nat_get_blkaddr(ne) == NULL_ADDR) {
1618 			write_lock(&nm_i->nat_tree_lock);
1619 			__del_from_nat_cache(nm_i, ne);
1620 			write_unlock(&nm_i->nat_tree_lock);
1621 
1622 			/* We can reuse this freed nid at this point */
1623 			add_free_nid(NM_I(sbi), nid);
1624 		} else {
1625 			write_lock(&nm_i->nat_tree_lock);
1626 			__clear_nat_cache_dirty(nm_i, ne);
1627 			ne->checkpointed = true;
1628 			write_unlock(&nm_i->nat_tree_lock);
1629 		}
1630 	}
1631 	if (!flushed)
1632 		mutex_unlock(&curseg->curseg_mutex);
1633 	f2fs_put_page(page, 1);
1634 
1635 	/* 2) shrink nat caches if necessary */
1636 	try_to_free_nats(sbi, nm_i->nat_cnt - NM_WOUT_THRESHOLD);
1637 }
1638 
1639 static int init_node_manager(struct f2fs_sb_info *sbi)
1640 {
1641 	struct f2fs_super_block *sb_raw = F2FS_RAW_SUPER(sbi);
1642 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1643 	unsigned char *version_bitmap;
1644 	unsigned int nat_segs, nat_blocks;
1645 
1646 	nm_i->nat_blkaddr = le32_to_cpu(sb_raw->nat_blkaddr);
1647 
1648 	/* segment_count_nat includes pair segment so divide to 2. */
1649 	nat_segs = le32_to_cpu(sb_raw->segment_count_nat) >> 1;
1650 	nat_blocks = nat_segs << le32_to_cpu(sb_raw->log_blocks_per_seg);
1651 	nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks;
1652 	nm_i->fcnt = 0;
1653 	nm_i->nat_cnt = 0;
1654 
1655 	INIT_LIST_HEAD(&nm_i->free_nid_list);
1656 	INIT_RADIX_TREE(&nm_i->nat_root, GFP_ATOMIC);
1657 	INIT_LIST_HEAD(&nm_i->nat_entries);
1658 	INIT_LIST_HEAD(&nm_i->dirty_nat_entries);
1659 
1660 	mutex_init(&nm_i->build_lock);
1661 	spin_lock_init(&nm_i->free_nid_list_lock);
1662 	rwlock_init(&nm_i->nat_tree_lock);
1663 
1664 	nm_i->bitmap_size = __bitmap_size(sbi, NAT_BITMAP);
1665 	nm_i->init_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
1666 	nm_i->next_scan_nid = le32_to_cpu(sbi->ckpt->next_free_nid);
1667 
1668 	nm_i->nat_bitmap = kzalloc(nm_i->bitmap_size, GFP_KERNEL);
1669 	if (!nm_i->nat_bitmap)
1670 		return -ENOMEM;
1671 	version_bitmap = __bitmap_ptr(sbi, NAT_BITMAP);
1672 	if (!version_bitmap)
1673 		return -EFAULT;
1674 
1675 	/* copy version bitmap */
1676 	memcpy(nm_i->nat_bitmap, version_bitmap, nm_i->bitmap_size);
1677 	return 0;
1678 }
1679 
1680 int build_node_manager(struct f2fs_sb_info *sbi)
1681 {
1682 	int err;
1683 
1684 	sbi->nm_info = kzalloc(sizeof(struct f2fs_nm_info), GFP_KERNEL);
1685 	if (!sbi->nm_info)
1686 		return -ENOMEM;
1687 
1688 	err = init_node_manager(sbi);
1689 	if (err)
1690 		return err;
1691 
1692 	build_free_nids(sbi);
1693 	return 0;
1694 }
1695 
1696 void destroy_node_manager(struct f2fs_sb_info *sbi)
1697 {
1698 	struct f2fs_nm_info *nm_i = NM_I(sbi);
1699 	struct free_nid *i, *next_i;
1700 	struct nat_entry *natvec[NATVEC_SIZE];
1701 	nid_t nid = 0;
1702 	unsigned int found;
1703 
1704 	if (!nm_i)
1705 		return;
1706 
1707 	/* destroy free nid list */
1708 	spin_lock(&nm_i->free_nid_list_lock);
1709 	list_for_each_entry_safe(i, next_i, &nm_i->free_nid_list, list) {
1710 		BUG_ON(i->state == NID_ALLOC);
1711 		__del_from_free_nid_list(i);
1712 		nm_i->fcnt--;
1713 	}
1714 	BUG_ON(nm_i->fcnt);
1715 	spin_unlock(&nm_i->free_nid_list_lock);
1716 
1717 	/* destroy nat cache */
1718 	write_lock(&nm_i->nat_tree_lock);
1719 	while ((found = __gang_lookup_nat_cache(nm_i,
1720 					nid, NATVEC_SIZE, natvec))) {
1721 		unsigned idx;
1722 		for (idx = 0; idx < found; idx++) {
1723 			struct nat_entry *e = natvec[idx];
1724 			nid = nat_get_nid(e) + 1;
1725 			__del_from_nat_cache(nm_i, e);
1726 		}
1727 	}
1728 	BUG_ON(nm_i->nat_cnt);
1729 	write_unlock(&nm_i->nat_tree_lock);
1730 
1731 	kfree(nm_i->nat_bitmap);
1732 	sbi->nm_info = NULL;
1733 	kfree(nm_i);
1734 }
1735 
1736 int __init create_node_manager_caches(void)
1737 {
1738 	nat_entry_slab = f2fs_kmem_cache_create("nat_entry",
1739 			sizeof(struct nat_entry), NULL);
1740 	if (!nat_entry_slab)
1741 		return -ENOMEM;
1742 
1743 	free_nid_slab = f2fs_kmem_cache_create("free_nid",
1744 			sizeof(struct free_nid), NULL);
1745 	if (!free_nid_slab) {
1746 		kmem_cache_destroy(nat_entry_slab);
1747 		return -ENOMEM;
1748 	}
1749 	return 0;
1750 }
1751 
1752 void destroy_node_manager_caches(void)
1753 {
1754 	kmem_cache_destroy(free_nid_slab);
1755 	kmem_cache_destroy(nat_entry_slab);
1756 }
1757