xref: /linux/fs/f2fs/data.c (revision 2a2c74b2efcb1a0ca3fdcb5fbb96ad8de6a29177)
1 /*
2  * fs/f2fs/data.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/buffer_head.h>
14 #include <linux/mpage.h>
15 #include <linux/aio.h>
16 #include <linux/writeback.h>
17 #include <linux/backing-dev.h>
18 #include <linux/blkdev.h>
19 #include <linux/bio.h>
20 #include <linux/prefetch.h>
21 
22 #include "f2fs.h"
23 #include "node.h"
24 #include "segment.h"
25 #include <trace/events/f2fs.h>
26 
27 static void f2fs_read_end_io(struct bio *bio, int err)
28 {
29 	struct bio_vec *bvec;
30 	int i;
31 
32 	bio_for_each_segment_all(bvec, bio, i) {
33 		struct page *page = bvec->bv_page;
34 
35 		if (!err) {
36 			SetPageUptodate(page);
37 		} else {
38 			ClearPageUptodate(page);
39 			SetPageError(page);
40 		}
41 		unlock_page(page);
42 	}
43 	bio_put(bio);
44 }
45 
46 static void f2fs_write_end_io(struct bio *bio, int err)
47 {
48 	struct f2fs_sb_info *sbi = bio->bi_private;
49 	struct bio_vec *bvec;
50 	int i;
51 
52 	bio_for_each_segment_all(bvec, bio, i) {
53 		struct page *page = bvec->bv_page;
54 
55 		if (unlikely(err)) {
56 			SetPageError(page);
57 			set_bit(AS_EIO, &page->mapping->flags);
58 			f2fs_stop_checkpoint(sbi);
59 		}
60 		end_page_writeback(page);
61 		dec_page_count(sbi, F2FS_WRITEBACK);
62 	}
63 
64 	if (sbi->wait_io) {
65 		complete(sbi->wait_io);
66 		sbi->wait_io = NULL;
67 	}
68 
69 	if (!get_pages(sbi, F2FS_WRITEBACK) &&
70 			!list_empty(&sbi->cp_wait.task_list))
71 		wake_up(&sbi->cp_wait);
72 
73 	bio_put(bio);
74 }
75 
76 /*
77  * Low-level block read/write IO operations.
78  */
79 static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
80 				int npages, bool is_read)
81 {
82 	struct bio *bio;
83 
84 	/* No failure on bio allocation */
85 	bio = bio_alloc(GFP_NOIO, npages);
86 
87 	bio->bi_bdev = sbi->sb->s_bdev;
88 	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(sbi, blk_addr);
89 	bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;
90 	bio->bi_private = sbi;
91 
92 	return bio;
93 }
94 
95 static void __submit_merged_bio(struct f2fs_bio_info *io)
96 {
97 	struct f2fs_io_info *fio = &io->fio;
98 	int rw;
99 
100 	if (!io->bio)
101 		return;
102 
103 	rw = fio->rw;
104 
105 	if (is_read_io(rw)) {
106 		trace_f2fs_submit_read_bio(io->sbi->sb, rw,
107 						fio->type, io->bio);
108 		submit_bio(rw, io->bio);
109 	} else {
110 		trace_f2fs_submit_write_bio(io->sbi->sb, rw,
111 						fio->type, io->bio);
112 		/*
113 		 * META_FLUSH is only from the checkpoint procedure, and we
114 		 * should wait this metadata bio for FS consistency.
115 		 */
116 		if (fio->type == META_FLUSH) {
117 			DECLARE_COMPLETION_ONSTACK(wait);
118 			io->sbi->wait_io = &wait;
119 			submit_bio(rw, io->bio);
120 			wait_for_completion(&wait);
121 		} else {
122 			submit_bio(rw, io->bio);
123 		}
124 	}
125 
126 	io->bio = NULL;
127 }
128 
129 void f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
130 				enum page_type type, int rw)
131 {
132 	enum page_type btype = PAGE_TYPE_OF_BIO(type);
133 	struct f2fs_bio_info *io;
134 
135 	io = is_read_io(rw) ? &sbi->read_io : &sbi->write_io[btype];
136 
137 	down_write(&io->io_rwsem);
138 
139 	/* change META to META_FLUSH in the checkpoint procedure */
140 	if (type >= META_FLUSH) {
141 		io->fio.type = META_FLUSH;
142 		io->fio.rw = WRITE_FLUSH_FUA | REQ_META | REQ_PRIO;
143 	}
144 	__submit_merged_bio(io);
145 	up_write(&io->io_rwsem);
146 }
147 
148 /*
149  * Fill the locked page with data located in the block address.
150  * Return unlocked page.
151  */
152 int f2fs_submit_page_bio(struct f2fs_sb_info *sbi, struct page *page,
153 					block_t blk_addr, int rw)
154 {
155 	struct bio *bio;
156 
157 	trace_f2fs_submit_page_bio(page, blk_addr, rw);
158 
159 	/* Allocate a new bio */
160 	bio = __bio_alloc(sbi, blk_addr, 1, is_read_io(rw));
161 
162 	if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
163 		bio_put(bio);
164 		f2fs_put_page(page, 1);
165 		return -EFAULT;
166 	}
167 
168 	submit_bio(rw, bio);
169 	return 0;
170 }
171 
172 void f2fs_submit_page_mbio(struct f2fs_sb_info *sbi, struct page *page,
173 			block_t blk_addr, struct f2fs_io_info *fio)
174 {
175 	enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);
176 	struct f2fs_bio_info *io;
177 	bool is_read = is_read_io(fio->rw);
178 
179 	io = is_read ? &sbi->read_io : &sbi->write_io[btype];
180 
181 	verify_block_addr(sbi, blk_addr);
182 
183 	down_write(&io->io_rwsem);
184 
185 	if (!is_read)
186 		inc_page_count(sbi, F2FS_WRITEBACK);
187 
188 	if (io->bio && (io->last_block_in_bio != blk_addr - 1 ||
189 						io->fio.rw != fio->rw))
190 		__submit_merged_bio(io);
191 alloc_new:
192 	if (io->bio == NULL) {
193 		int bio_blocks = MAX_BIO_BLOCKS(max_hw_blocks(sbi));
194 
195 		io->bio = __bio_alloc(sbi, blk_addr, bio_blocks, is_read);
196 		io->fio = *fio;
197 	}
198 
199 	if (bio_add_page(io->bio, page, PAGE_CACHE_SIZE, 0) <
200 							PAGE_CACHE_SIZE) {
201 		__submit_merged_bio(io);
202 		goto alloc_new;
203 	}
204 
205 	io->last_block_in_bio = blk_addr;
206 
207 	up_write(&io->io_rwsem);
208 	trace_f2fs_submit_page_mbio(page, fio->rw, fio->type, blk_addr);
209 }
210 
211 /*
212  * Lock ordering for the change of data block address:
213  * ->data_page
214  *  ->node_page
215  *    update block addresses in the node page
216  */
217 static void __set_data_blkaddr(struct dnode_of_data *dn, block_t new_addr)
218 {
219 	struct f2fs_node *rn;
220 	__le32 *addr_array;
221 	struct page *node_page = dn->node_page;
222 	unsigned int ofs_in_node = dn->ofs_in_node;
223 
224 	f2fs_wait_on_page_writeback(node_page, NODE);
225 
226 	rn = F2FS_NODE(node_page);
227 
228 	/* Get physical address of data block */
229 	addr_array = blkaddr_in_node(rn);
230 	addr_array[ofs_in_node] = cpu_to_le32(new_addr);
231 	set_page_dirty(node_page);
232 }
233 
234 int reserve_new_block(struct dnode_of_data *dn)
235 {
236 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
237 
238 	if (unlikely(is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC)))
239 		return -EPERM;
240 	if (unlikely(!inc_valid_block_count(sbi, dn->inode, 1)))
241 		return -ENOSPC;
242 
243 	trace_f2fs_reserve_new_block(dn->inode, dn->nid, dn->ofs_in_node);
244 
245 	__set_data_blkaddr(dn, NEW_ADDR);
246 	dn->data_blkaddr = NEW_ADDR;
247 	mark_inode_dirty(dn->inode);
248 	sync_inode_page(dn);
249 	return 0;
250 }
251 
252 int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index)
253 {
254 	bool need_put = dn->inode_page ? false : true;
255 	int err;
256 
257 	/* if inode_page exists, index should be zero */
258 	f2fs_bug_on(!need_put && index);
259 
260 	err = get_dnode_of_data(dn, index, ALLOC_NODE);
261 	if (err)
262 		return err;
263 
264 	if (dn->data_blkaddr == NULL_ADDR)
265 		err = reserve_new_block(dn);
266 	if (err || need_put)
267 		f2fs_put_dnode(dn);
268 	return err;
269 }
270 
271 static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
272 					struct buffer_head *bh_result)
273 {
274 	struct f2fs_inode_info *fi = F2FS_I(inode);
275 	pgoff_t start_fofs, end_fofs;
276 	block_t start_blkaddr;
277 
278 	if (is_inode_flag_set(fi, FI_NO_EXTENT))
279 		return 0;
280 
281 	read_lock(&fi->ext.ext_lock);
282 	if (fi->ext.len == 0) {
283 		read_unlock(&fi->ext.ext_lock);
284 		return 0;
285 	}
286 
287 	stat_inc_total_hit(inode->i_sb);
288 
289 	start_fofs = fi->ext.fofs;
290 	end_fofs = fi->ext.fofs + fi->ext.len - 1;
291 	start_blkaddr = fi->ext.blk_addr;
292 
293 	if (pgofs >= start_fofs && pgofs <= end_fofs) {
294 		unsigned int blkbits = inode->i_sb->s_blocksize_bits;
295 		size_t count;
296 
297 		clear_buffer_new(bh_result);
298 		map_bh(bh_result, inode->i_sb,
299 				start_blkaddr + pgofs - start_fofs);
300 		count = end_fofs - pgofs + 1;
301 		if (count < (UINT_MAX >> blkbits))
302 			bh_result->b_size = (count << blkbits);
303 		else
304 			bh_result->b_size = UINT_MAX;
305 
306 		stat_inc_read_hit(inode->i_sb);
307 		read_unlock(&fi->ext.ext_lock);
308 		return 1;
309 	}
310 	read_unlock(&fi->ext.ext_lock);
311 	return 0;
312 }
313 
314 void update_extent_cache(block_t blk_addr, struct dnode_of_data *dn)
315 {
316 	struct f2fs_inode_info *fi = F2FS_I(dn->inode);
317 	pgoff_t fofs, start_fofs, end_fofs;
318 	block_t start_blkaddr, end_blkaddr;
319 	int need_update = true;
320 
321 	f2fs_bug_on(blk_addr == NEW_ADDR);
322 	fofs = start_bidx_of_node(ofs_of_node(dn->node_page), fi) +
323 							dn->ofs_in_node;
324 
325 	/* Update the page address in the parent node */
326 	__set_data_blkaddr(dn, blk_addr);
327 
328 	if (is_inode_flag_set(fi, FI_NO_EXTENT))
329 		return;
330 
331 	write_lock(&fi->ext.ext_lock);
332 
333 	start_fofs = fi->ext.fofs;
334 	end_fofs = fi->ext.fofs + fi->ext.len - 1;
335 	start_blkaddr = fi->ext.blk_addr;
336 	end_blkaddr = fi->ext.blk_addr + fi->ext.len - 1;
337 
338 	/* Drop and initialize the matched extent */
339 	if (fi->ext.len == 1 && fofs == start_fofs)
340 		fi->ext.len = 0;
341 
342 	/* Initial extent */
343 	if (fi->ext.len == 0) {
344 		if (blk_addr != NULL_ADDR) {
345 			fi->ext.fofs = fofs;
346 			fi->ext.blk_addr = blk_addr;
347 			fi->ext.len = 1;
348 		}
349 		goto end_update;
350 	}
351 
352 	/* Front merge */
353 	if (fofs == start_fofs - 1 && blk_addr == start_blkaddr - 1) {
354 		fi->ext.fofs--;
355 		fi->ext.blk_addr--;
356 		fi->ext.len++;
357 		goto end_update;
358 	}
359 
360 	/* Back merge */
361 	if (fofs == end_fofs + 1 && blk_addr == end_blkaddr + 1) {
362 		fi->ext.len++;
363 		goto end_update;
364 	}
365 
366 	/* Split the existing extent */
367 	if (fi->ext.len > 1 &&
368 		fofs >= start_fofs && fofs <= end_fofs) {
369 		if ((end_fofs - fofs) < (fi->ext.len >> 1)) {
370 			fi->ext.len = fofs - start_fofs;
371 		} else {
372 			fi->ext.fofs = fofs + 1;
373 			fi->ext.blk_addr = start_blkaddr +
374 					fofs - start_fofs + 1;
375 			fi->ext.len -= fofs - start_fofs + 1;
376 		}
377 	} else {
378 		need_update = false;
379 	}
380 
381 	/* Finally, if the extent is very fragmented, let's drop the cache. */
382 	if (fi->ext.len < F2FS_MIN_EXTENT_LEN) {
383 		fi->ext.len = 0;
384 		set_inode_flag(fi, FI_NO_EXTENT);
385 		need_update = true;
386 	}
387 end_update:
388 	write_unlock(&fi->ext.ext_lock);
389 	if (need_update)
390 		sync_inode_page(dn);
391 	return;
392 }
393 
394 struct page *find_data_page(struct inode *inode, pgoff_t index, bool sync)
395 {
396 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
397 	struct address_space *mapping = inode->i_mapping;
398 	struct dnode_of_data dn;
399 	struct page *page;
400 	int err;
401 
402 	page = find_get_page(mapping, index);
403 	if (page && PageUptodate(page))
404 		return page;
405 	f2fs_put_page(page, 0);
406 
407 	set_new_dnode(&dn, inode, NULL, NULL, 0);
408 	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
409 	if (err)
410 		return ERR_PTR(err);
411 	f2fs_put_dnode(&dn);
412 
413 	if (dn.data_blkaddr == NULL_ADDR)
414 		return ERR_PTR(-ENOENT);
415 
416 	/* By fallocate(), there is no cached page, but with NEW_ADDR */
417 	if (unlikely(dn.data_blkaddr == NEW_ADDR))
418 		return ERR_PTR(-EINVAL);
419 
420 	page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
421 	if (!page)
422 		return ERR_PTR(-ENOMEM);
423 
424 	if (PageUptodate(page)) {
425 		unlock_page(page);
426 		return page;
427 	}
428 
429 	err = f2fs_submit_page_bio(sbi, page, dn.data_blkaddr,
430 					sync ? READ_SYNC : READA);
431 	if (err)
432 		return ERR_PTR(err);
433 
434 	if (sync) {
435 		wait_on_page_locked(page);
436 		if (unlikely(!PageUptodate(page))) {
437 			f2fs_put_page(page, 0);
438 			return ERR_PTR(-EIO);
439 		}
440 	}
441 	return page;
442 }
443 
444 /*
445  * If it tries to access a hole, return an error.
446  * Because, the callers, functions in dir.c and GC, should be able to know
447  * whether this page exists or not.
448  */
449 struct page *get_lock_data_page(struct inode *inode, pgoff_t index)
450 {
451 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
452 	struct address_space *mapping = inode->i_mapping;
453 	struct dnode_of_data dn;
454 	struct page *page;
455 	int err;
456 
457 repeat:
458 	page = grab_cache_page_write_begin(mapping, index, AOP_FLAG_NOFS);
459 	if (!page)
460 		return ERR_PTR(-ENOMEM);
461 
462 	set_new_dnode(&dn, inode, NULL, NULL, 0);
463 	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
464 	if (err) {
465 		f2fs_put_page(page, 1);
466 		return ERR_PTR(err);
467 	}
468 	f2fs_put_dnode(&dn);
469 
470 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
471 		f2fs_put_page(page, 1);
472 		return ERR_PTR(-ENOENT);
473 	}
474 
475 	if (PageUptodate(page))
476 		return page;
477 
478 	/*
479 	 * A new dentry page is allocated but not able to be written, since its
480 	 * new inode page couldn't be allocated due to -ENOSPC.
481 	 * In such the case, its blkaddr can be remained as NEW_ADDR.
482 	 * see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
483 	 */
484 	if (dn.data_blkaddr == NEW_ADDR) {
485 		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
486 		SetPageUptodate(page);
487 		return page;
488 	}
489 
490 	err = f2fs_submit_page_bio(sbi, page, dn.data_blkaddr, READ_SYNC);
491 	if (err)
492 		return ERR_PTR(err);
493 
494 	lock_page(page);
495 	if (unlikely(!PageUptodate(page))) {
496 		f2fs_put_page(page, 1);
497 		return ERR_PTR(-EIO);
498 	}
499 	if (unlikely(page->mapping != mapping)) {
500 		f2fs_put_page(page, 1);
501 		goto repeat;
502 	}
503 	return page;
504 }
505 
506 /*
507  * Caller ensures that this data page is never allocated.
508  * A new zero-filled data page is allocated in the page cache.
509  *
510  * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
511  * f2fs_unlock_op().
512  * Note that, ipage is set only by make_empty_dir.
513  */
514 struct page *get_new_data_page(struct inode *inode,
515 		struct page *ipage, pgoff_t index, bool new_i_size)
516 {
517 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
518 	struct address_space *mapping = inode->i_mapping;
519 	struct page *page;
520 	struct dnode_of_data dn;
521 	int err;
522 
523 	set_new_dnode(&dn, inode, ipage, NULL, 0);
524 	err = f2fs_reserve_block(&dn, index);
525 	if (err)
526 		return ERR_PTR(err);
527 repeat:
528 	page = grab_cache_page(mapping, index);
529 	if (!page) {
530 		err = -ENOMEM;
531 		goto put_err;
532 	}
533 
534 	if (PageUptodate(page))
535 		return page;
536 
537 	if (dn.data_blkaddr == NEW_ADDR) {
538 		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
539 		SetPageUptodate(page);
540 	} else {
541 		err = f2fs_submit_page_bio(sbi, page, dn.data_blkaddr,
542 								READ_SYNC);
543 		if (err)
544 			goto put_err;
545 
546 		lock_page(page);
547 		if (unlikely(!PageUptodate(page))) {
548 			f2fs_put_page(page, 1);
549 			err = -EIO;
550 			goto put_err;
551 		}
552 		if (unlikely(page->mapping != mapping)) {
553 			f2fs_put_page(page, 1);
554 			goto repeat;
555 		}
556 	}
557 
558 	if (new_i_size &&
559 		i_size_read(inode) < ((index + 1) << PAGE_CACHE_SHIFT)) {
560 		i_size_write(inode, ((index + 1) << PAGE_CACHE_SHIFT));
561 		/* Only the directory inode sets new_i_size */
562 		set_inode_flag(F2FS_I(inode), FI_UPDATE_DIR);
563 	}
564 	return page;
565 
566 put_err:
567 	f2fs_put_dnode(&dn);
568 	return ERR_PTR(err);
569 }
570 
571 static int __allocate_data_block(struct dnode_of_data *dn)
572 {
573 	struct f2fs_sb_info *sbi = F2FS_SB(dn->inode->i_sb);
574 	struct f2fs_summary sum;
575 	block_t new_blkaddr;
576 	struct node_info ni;
577 	int type;
578 
579 	if (unlikely(is_inode_flag_set(F2FS_I(dn->inode), FI_NO_ALLOC)))
580 		return -EPERM;
581 	if (unlikely(!inc_valid_block_count(sbi, dn->inode, 1)))
582 		return -ENOSPC;
583 
584 	__set_data_blkaddr(dn, NEW_ADDR);
585 	dn->data_blkaddr = NEW_ADDR;
586 
587 	get_node_info(sbi, dn->nid, &ni);
588 	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
589 
590 	type = CURSEG_WARM_DATA;
591 
592 	allocate_data_block(sbi, NULL, NULL_ADDR, &new_blkaddr, &sum, type);
593 
594 	/* direct IO doesn't use extent cache to maximize the performance */
595 	set_inode_flag(F2FS_I(dn->inode), FI_NO_EXTENT);
596 	update_extent_cache(new_blkaddr, dn);
597 	clear_inode_flag(F2FS_I(dn->inode), FI_NO_EXTENT);
598 
599 	dn->data_blkaddr = new_blkaddr;
600 	return 0;
601 }
602 
603 /*
604  * get_data_block() now supported readahead/bmap/rw direct_IO with mapped bh.
605  * If original data blocks are allocated, then give them to blockdev.
606  * Otherwise,
607  *     a. preallocate requested block addresses
608  *     b. do not use extent cache for better performance
609  *     c. give the block addresses to blockdev
610  */
611 static int get_data_block(struct inode *inode, sector_t iblock,
612 			struct buffer_head *bh_result, int create)
613 {
614 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
615 	unsigned int blkbits = inode->i_sb->s_blocksize_bits;
616 	unsigned maxblocks = bh_result->b_size >> blkbits;
617 	struct dnode_of_data dn;
618 	int mode = create ? ALLOC_NODE : LOOKUP_NODE_RA;
619 	pgoff_t pgofs, end_offset;
620 	int err = 0, ofs = 1;
621 	bool allocated = false;
622 
623 	/* Get the page offset from the block offset(iblock) */
624 	pgofs =	(pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
625 
626 	if (check_extent_cache(inode, pgofs, bh_result))
627 		goto out;
628 
629 	if (create)
630 		f2fs_lock_op(sbi);
631 
632 	/* When reading holes, we need its node page */
633 	set_new_dnode(&dn, inode, NULL, NULL, 0);
634 	err = get_dnode_of_data(&dn, pgofs, mode);
635 	if (err) {
636 		if (err == -ENOENT)
637 			err = 0;
638 		goto unlock_out;
639 	}
640 	if (dn.data_blkaddr == NEW_ADDR)
641 		goto put_out;
642 
643 	if (dn.data_blkaddr != NULL_ADDR) {
644 		map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
645 	} else if (create) {
646 		err = __allocate_data_block(&dn);
647 		if (err)
648 			goto put_out;
649 		allocated = true;
650 		map_bh(bh_result, inode->i_sb, dn.data_blkaddr);
651 	} else {
652 		goto put_out;
653 	}
654 
655 	end_offset = IS_INODE(dn.node_page) ?
656 			ADDRS_PER_INODE(F2FS_I(inode)) : ADDRS_PER_BLOCK;
657 	bh_result->b_size = (((size_t)1) << blkbits);
658 	dn.ofs_in_node++;
659 	pgofs++;
660 
661 get_next:
662 	if (dn.ofs_in_node >= end_offset) {
663 		if (allocated)
664 			sync_inode_page(&dn);
665 		allocated = false;
666 		f2fs_put_dnode(&dn);
667 
668 		set_new_dnode(&dn, inode, NULL, NULL, 0);
669 		err = get_dnode_of_data(&dn, pgofs, mode);
670 		if (err) {
671 			if (err == -ENOENT)
672 				err = 0;
673 			goto unlock_out;
674 		}
675 		if (dn.data_blkaddr == NEW_ADDR)
676 			goto put_out;
677 
678 		end_offset = IS_INODE(dn.node_page) ?
679 			ADDRS_PER_INODE(F2FS_I(inode)) : ADDRS_PER_BLOCK;
680 	}
681 
682 	if (maxblocks > (bh_result->b_size >> blkbits)) {
683 		block_t blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
684 		if (blkaddr == NULL_ADDR && create) {
685 			err = __allocate_data_block(&dn);
686 			if (err)
687 				goto sync_out;
688 			allocated = true;
689 			blkaddr = dn.data_blkaddr;
690 		}
691 		/* Give more consecutive addresses for the read ahead */
692 		if (blkaddr == (bh_result->b_blocknr + ofs)) {
693 			ofs++;
694 			dn.ofs_in_node++;
695 			pgofs++;
696 			bh_result->b_size += (((size_t)1) << blkbits);
697 			goto get_next;
698 		}
699 	}
700 sync_out:
701 	if (allocated)
702 		sync_inode_page(&dn);
703 put_out:
704 	f2fs_put_dnode(&dn);
705 unlock_out:
706 	if (create)
707 		f2fs_unlock_op(sbi);
708 out:
709 	trace_f2fs_get_data_block(inode, iblock, bh_result, err);
710 	return err;
711 }
712 
713 static int f2fs_read_data_page(struct file *file, struct page *page)
714 {
715 	struct inode *inode = page->mapping->host;
716 	int ret;
717 
718 	/* If the file has inline data, try to read it directlly */
719 	if (f2fs_has_inline_data(inode))
720 		ret = f2fs_read_inline_data(inode, page);
721 	else
722 		ret = mpage_readpage(page, get_data_block);
723 
724 	return ret;
725 }
726 
727 static int f2fs_read_data_pages(struct file *file,
728 			struct address_space *mapping,
729 			struct list_head *pages, unsigned nr_pages)
730 {
731 	struct inode *inode = file->f_mapping->host;
732 
733 	/* If the file has inline data, skip readpages */
734 	if (f2fs_has_inline_data(inode))
735 		return 0;
736 
737 	return mpage_readpages(mapping, pages, nr_pages, get_data_block);
738 }
739 
740 int do_write_data_page(struct page *page, struct f2fs_io_info *fio)
741 {
742 	struct inode *inode = page->mapping->host;
743 	block_t old_blkaddr, new_blkaddr;
744 	struct dnode_of_data dn;
745 	int err = 0;
746 
747 	set_new_dnode(&dn, inode, NULL, NULL, 0);
748 	err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
749 	if (err)
750 		return err;
751 
752 	old_blkaddr = dn.data_blkaddr;
753 
754 	/* This page is already truncated */
755 	if (old_blkaddr == NULL_ADDR)
756 		goto out_writepage;
757 
758 	set_page_writeback(page);
759 
760 	/*
761 	 * If current allocation needs SSR,
762 	 * it had better in-place writes for updated data.
763 	 */
764 	if (unlikely(old_blkaddr != NEW_ADDR &&
765 			!is_cold_data(page) &&
766 			need_inplace_update(inode))) {
767 		rewrite_data_page(page, old_blkaddr, fio);
768 	} else {
769 		write_data_page(page, &dn, &new_blkaddr, fio);
770 		update_extent_cache(new_blkaddr, &dn);
771 	}
772 out_writepage:
773 	f2fs_put_dnode(&dn);
774 	return err;
775 }
776 
777 static int f2fs_write_data_page(struct page *page,
778 					struct writeback_control *wbc)
779 {
780 	struct inode *inode = page->mapping->host;
781 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
782 	loff_t i_size = i_size_read(inode);
783 	const pgoff_t end_index = ((unsigned long long) i_size)
784 							>> PAGE_CACHE_SHIFT;
785 	unsigned offset = 0;
786 	bool need_balance_fs = false;
787 	int err = 0;
788 	struct f2fs_io_info fio = {
789 		.type = DATA,
790 		.rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE,
791 	};
792 
793 	if (page->index < end_index)
794 		goto write;
795 
796 	/*
797 	 * If the offset is out-of-range of file size,
798 	 * this page does not have to be written to disk.
799 	 */
800 	offset = i_size & (PAGE_CACHE_SIZE - 1);
801 	if ((page->index >= end_index + 1) || !offset) {
802 		inode_dec_dirty_dents(inode);
803 		goto out;
804 	}
805 
806 	zero_user_segment(page, offset, PAGE_CACHE_SIZE);
807 write:
808 	if (unlikely(sbi->por_doing))
809 		goto redirty_out;
810 
811 	/* Dentry blocks are controlled by checkpoint */
812 	if (S_ISDIR(inode->i_mode)) {
813 		inode_dec_dirty_dents(inode);
814 		err = do_write_data_page(page, &fio);
815 		goto done;
816 	}
817 
818 	if (!wbc->for_reclaim)
819 		need_balance_fs = true;
820 	else if (has_not_enough_free_secs(sbi, 0))
821 		goto redirty_out;
822 
823 	f2fs_lock_op(sbi);
824 	if (f2fs_has_inline_data(inode) || f2fs_may_inline(inode))
825 		err = f2fs_write_inline_data(inode, page, offset);
826 	else
827 		err = do_write_data_page(page, &fio);
828 	f2fs_unlock_op(sbi);
829 done:
830 	if (err && err != -ENOENT)
831 		goto redirty_out;
832 
833 	clear_cold_data(page);
834 out:
835 	unlock_page(page);
836 	if (need_balance_fs)
837 		f2fs_balance_fs(sbi);
838 	return 0;
839 
840 redirty_out:
841 	wbc->pages_skipped++;
842 	account_page_redirty(page);
843 	set_page_dirty(page);
844 	return AOP_WRITEPAGE_ACTIVATE;
845 }
846 
847 static int __f2fs_writepage(struct page *page, struct writeback_control *wbc,
848 			void *data)
849 {
850 	struct address_space *mapping = data;
851 	int ret = mapping->a_ops->writepage(page, wbc);
852 	mapping_set_error(mapping, ret);
853 	return ret;
854 }
855 
856 static int f2fs_write_data_pages(struct address_space *mapping,
857 			    struct writeback_control *wbc)
858 {
859 	struct inode *inode = mapping->host;
860 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
861 	bool locked = false;
862 	int ret;
863 	long diff;
864 
865 	/* deal with chardevs and other special file */
866 	if (!mapping->a_ops->writepage)
867 		return 0;
868 
869 	if (S_ISDIR(inode->i_mode) && wbc->sync_mode == WB_SYNC_NONE &&
870 			get_dirty_dents(inode) < nr_pages_to_skip(sbi, DATA))
871 		goto skip_write;
872 
873 	diff = nr_pages_to_write(sbi, DATA, wbc);
874 
875 	if (!S_ISDIR(inode->i_mode)) {
876 		mutex_lock(&sbi->writepages);
877 		locked = true;
878 	}
879 	ret = write_cache_pages(mapping, wbc, __f2fs_writepage, mapping);
880 	if (locked)
881 		mutex_unlock(&sbi->writepages);
882 
883 	f2fs_submit_merged_bio(sbi, DATA, WRITE);
884 
885 	remove_dirty_dir_inode(inode);
886 
887 	wbc->nr_to_write = max((long)0, wbc->nr_to_write - diff);
888 	return ret;
889 
890 skip_write:
891 	wbc->pages_skipped += get_dirty_dents(inode);
892 	return 0;
893 }
894 
895 static int f2fs_write_begin(struct file *file, struct address_space *mapping,
896 		loff_t pos, unsigned len, unsigned flags,
897 		struct page **pagep, void **fsdata)
898 {
899 	struct inode *inode = mapping->host;
900 	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
901 	struct page *page;
902 	pgoff_t index = ((unsigned long long) pos) >> PAGE_CACHE_SHIFT;
903 	struct dnode_of_data dn;
904 	int err = 0;
905 
906 	f2fs_balance_fs(sbi);
907 repeat:
908 	err = f2fs_convert_inline_data(inode, pos + len);
909 	if (err)
910 		return err;
911 
912 	page = grab_cache_page_write_begin(mapping, index, flags);
913 	if (!page)
914 		return -ENOMEM;
915 	*pagep = page;
916 
917 	if (f2fs_has_inline_data(inode) && (pos + len) <= MAX_INLINE_DATA)
918 		goto inline_data;
919 
920 	f2fs_lock_op(sbi);
921 	set_new_dnode(&dn, inode, NULL, NULL, 0);
922 	err = f2fs_reserve_block(&dn, index);
923 	f2fs_unlock_op(sbi);
924 
925 	if (err) {
926 		f2fs_put_page(page, 1);
927 		return err;
928 	}
929 inline_data:
930 	if ((len == PAGE_CACHE_SIZE) || PageUptodate(page))
931 		return 0;
932 
933 	if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) {
934 		unsigned start = pos & (PAGE_CACHE_SIZE - 1);
935 		unsigned end = start + len;
936 
937 		/* Reading beyond i_size is simple: memset to zero */
938 		zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE);
939 		goto out;
940 	}
941 
942 	if (dn.data_blkaddr == NEW_ADDR) {
943 		zero_user_segment(page, 0, PAGE_CACHE_SIZE);
944 	} else {
945 		if (f2fs_has_inline_data(inode)) {
946 			err = f2fs_read_inline_data(inode, page);
947 			if (err) {
948 				page_cache_release(page);
949 				return err;
950 			}
951 		} else {
952 			err = f2fs_submit_page_bio(sbi, page, dn.data_blkaddr,
953 							READ_SYNC);
954 			if (err)
955 				return err;
956 		}
957 
958 		lock_page(page);
959 		if (unlikely(!PageUptodate(page))) {
960 			f2fs_put_page(page, 1);
961 			return -EIO;
962 		}
963 		if (unlikely(page->mapping != mapping)) {
964 			f2fs_put_page(page, 1);
965 			goto repeat;
966 		}
967 	}
968 out:
969 	SetPageUptodate(page);
970 	clear_cold_data(page);
971 	return 0;
972 }
973 
974 static int f2fs_write_end(struct file *file,
975 			struct address_space *mapping,
976 			loff_t pos, unsigned len, unsigned copied,
977 			struct page *page, void *fsdata)
978 {
979 	struct inode *inode = page->mapping->host;
980 
981 	SetPageUptodate(page);
982 	set_page_dirty(page);
983 
984 	if (pos + copied > i_size_read(inode)) {
985 		i_size_write(inode, pos + copied);
986 		mark_inode_dirty(inode);
987 		update_inode_page(inode);
988 	}
989 
990 	f2fs_put_page(page, 1);
991 	return copied;
992 }
993 
994 static int check_direct_IO(struct inode *inode, int rw,
995 		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
996 {
997 	unsigned blocksize_mask = inode->i_sb->s_blocksize - 1;
998 	int i;
999 
1000 	if (rw == READ)
1001 		return 0;
1002 
1003 	if (offset & blocksize_mask)
1004 		return -EINVAL;
1005 
1006 	for (i = 0; i < nr_segs; i++)
1007 		if (iov[i].iov_len & blocksize_mask)
1008 			return -EINVAL;
1009 	return 0;
1010 }
1011 
1012 static ssize_t f2fs_direct_IO(int rw, struct kiocb *iocb,
1013 		const struct iovec *iov, loff_t offset, unsigned long nr_segs)
1014 {
1015 	struct file *file = iocb->ki_filp;
1016 	struct inode *inode = file->f_mapping->host;
1017 
1018 	/* Let buffer I/O handle the inline data case. */
1019 	if (f2fs_has_inline_data(inode))
1020 		return 0;
1021 
1022 	if (check_direct_IO(inode, rw, iov, offset, nr_segs))
1023 		return 0;
1024 
1025 	return blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
1026 							get_data_block);
1027 }
1028 
1029 static void f2fs_invalidate_data_page(struct page *page, unsigned int offset,
1030 				      unsigned int length)
1031 {
1032 	struct inode *inode = page->mapping->host;
1033 	if (PageDirty(page))
1034 		inode_dec_dirty_dents(inode);
1035 	ClearPagePrivate(page);
1036 }
1037 
1038 static int f2fs_release_data_page(struct page *page, gfp_t wait)
1039 {
1040 	ClearPagePrivate(page);
1041 	return 1;
1042 }
1043 
1044 static int f2fs_set_data_page_dirty(struct page *page)
1045 {
1046 	struct address_space *mapping = page->mapping;
1047 	struct inode *inode = mapping->host;
1048 
1049 	trace_f2fs_set_page_dirty(page, DATA);
1050 
1051 	SetPageUptodate(page);
1052 	mark_inode_dirty(inode);
1053 
1054 	if (!PageDirty(page)) {
1055 		__set_page_dirty_nobuffers(page);
1056 		set_dirty_dir_page(inode, page);
1057 		return 1;
1058 	}
1059 	return 0;
1060 }
1061 
1062 static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
1063 {
1064 	return generic_block_bmap(mapping, block, get_data_block);
1065 }
1066 
1067 const struct address_space_operations f2fs_dblock_aops = {
1068 	.readpage	= f2fs_read_data_page,
1069 	.readpages	= f2fs_read_data_pages,
1070 	.writepage	= f2fs_write_data_page,
1071 	.writepages	= f2fs_write_data_pages,
1072 	.write_begin	= f2fs_write_begin,
1073 	.write_end	= f2fs_write_end,
1074 	.set_page_dirty	= f2fs_set_data_page_dirty,
1075 	.invalidatepage	= f2fs_invalidate_data_page,
1076 	.releasepage	= f2fs_release_data_page,
1077 	.direct_IO	= f2fs_direct_IO,
1078 	.bmap		= f2fs_bmap,
1079 };
1080