xref: /openbmc/linux/fs/f2fs/data.c (revision 736c0a74856d762b09a997d28e3ff6d8bdcf942c)
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/writeback.h>
16 #include <linux/backing-dev.h>
17 #include <linux/pagevec.h>
18 #include <linux/blkdev.h>
19 #include <linux/bio.h>
20 #include <linux/prefetch.h>
21 #include <linux/uio.h>
22 #include <linux/mm.h>
23 #include <linux/memcontrol.h>
24 #include <linux/cleancache.h>
25 #include <linux/sched/signal.h>
26 
27 #include "f2fs.h"
28 #include "node.h"
29 #include "segment.h"
30 #include "trace.h"
31 #include <trace/events/f2fs.h>
32 
33 static bool __is_cp_guaranteed(struct page *page)
34 {
35 	struct address_space *mapping = page->mapping;
36 	struct inode *inode;
37 	struct f2fs_sb_info *sbi;
38 
39 	if (!mapping)
40 		return false;
41 
42 	inode = mapping->host;
43 	sbi = F2FS_I_SB(inode);
44 
45 	if (inode->i_ino == F2FS_META_INO(sbi) ||
46 			inode->i_ino ==  F2FS_NODE_INO(sbi) ||
47 			S_ISDIR(inode->i_mode) ||
48 			is_cold_data(page))
49 		return true;
50 	return false;
51 }
52 
53 static void f2fs_read_end_io(struct bio *bio)
54 {
55 	struct bio_vec *bvec;
56 	int i;
57 
58 #ifdef CONFIG_F2FS_FAULT_INJECTION
59 	if (time_to_inject(F2FS_P_SB(bio->bi_io_vec->bv_page), FAULT_IO)) {
60 		f2fs_show_injection_info(FAULT_IO);
61 		bio->bi_status = BLK_STS_IOERR;
62 	}
63 #endif
64 
65 	if (f2fs_bio_encrypted(bio)) {
66 		if (bio->bi_status) {
67 			fscrypt_release_ctx(bio->bi_private);
68 		} else {
69 			fscrypt_decrypt_bio_pages(bio->bi_private, bio);
70 			return;
71 		}
72 	}
73 
74 	bio_for_each_segment_all(bvec, bio, i) {
75 		struct page *page = bvec->bv_page;
76 
77 		if (!bio->bi_status) {
78 			if (!PageUptodate(page))
79 				SetPageUptodate(page);
80 		} else {
81 			ClearPageUptodate(page);
82 			SetPageError(page);
83 		}
84 		unlock_page(page);
85 	}
86 	bio_put(bio);
87 }
88 
89 static void f2fs_write_end_io(struct bio *bio)
90 {
91 	struct f2fs_sb_info *sbi = bio->bi_private;
92 	struct bio_vec *bvec;
93 	int i;
94 
95 	bio_for_each_segment_all(bvec, bio, i) {
96 		struct page *page = bvec->bv_page;
97 		enum count_type type = WB_DATA_TYPE(page);
98 
99 		if (IS_DUMMY_WRITTEN_PAGE(page)) {
100 			set_page_private(page, (unsigned long)NULL);
101 			ClearPagePrivate(page);
102 			unlock_page(page);
103 			mempool_free(page, sbi->write_io_dummy);
104 
105 			if (unlikely(bio->bi_status))
106 				f2fs_stop_checkpoint(sbi, true);
107 			continue;
108 		}
109 
110 		fscrypt_pullback_bio_page(&page, true);
111 
112 		if (unlikely(bio->bi_status)) {
113 			mapping_set_error(page->mapping, -EIO);
114 			f2fs_stop_checkpoint(sbi, true);
115 		}
116 		dec_page_count(sbi, type);
117 		clear_cold_data(page);
118 		end_page_writeback(page);
119 	}
120 	if (!get_pages(sbi, F2FS_WB_CP_DATA) &&
121 				wq_has_sleeper(&sbi->cp_wait))
122 		wake_up(&sbi->cp_wait);
123 
124 	bio_put(bio);
125 }
126 
127 /*
128  * Return true, if pre_bio's bdev is same as its target device.
129  */
130 struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
131 				block_t blk_addr, struct bio *bio)
132 {
133 	struct block_device *bdev = sbi->sb->s_bdev;
134 	int i;
135 
136 	for (i = 0; i < sbi->s_ndevs; i++) {
137 		if (FDEV(i).start_blk <= blk_addr &&
138 					FDEV(i).end_blk >= blk_addr) {
139 			blk_addr -= FDEV(i).start_blk;
140 			bdev = FDEV(i).bdev;
141 			break;
142 		}
143 	}
144 	if (bio) {
145 		bio_set_dev(bio, bdev);
146 		bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blk_addr);
147 	}
148 	return bdev;
149 }
150 
151 int f2fs_target_device_index(struct f2fs_sb_info *sbi, block_t blkaddr)
152 {
153 	int i;
154 
155 	for (i = 0; i < sbi->s_ndevs; i++)
156 		if (FDEV(i).start_blk <= blkaddr && FDEV(i).end_blk >= blkaddr)
157 			return i;
158 	return 0;
159 }
160 
161 static bool __same_bdev(struct f2fs_sb_info *sbi,
162 				block_t blk_addr, struct bio *bio)
163 {
164 	struct block_device *b = f2fs_target_device(sbi, blk_addr, NULL);
165 	return bio->bi_disk == b->bd_disk && bio->bi_partno == b->bd_partno;
166 }
167 
168 /*
169  * Low-level block read/write IO operations.
170  */
171 static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
172 				int npages, bool is_read)
173 {
174 	struct bio *bio;
175 
176 	bio = f2fs_bio_alloc(sbi, npages, true);
177 
178 	f2fs_target_device(sbi, blk_addr, bio);
179 	bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;
180 	bio->bi_private = is_read ? NULL : sbi;
181 
182 	return bio;
183 }
184 
185 static inline void __submit_bio(struct f2fs_sb_info *sbi,
186 				struct bio *bio, enum page_type type)
187 {
188 	if (!is_read_io(bio_op(bio))) {
189 		unsigned int start;
190 
191 		if (f2fs_sb_mounted_blkzoned(sbi->sb) &&
192 			current->plug && (type == DATA || type == NODE))
193 			blk_finish_plug(current->plug);
194 
195 		if (type != DATA && type != NODE)
196 			goto submit_io;
197 
198 		start = bio->bi_iter.bi_size >> F2FS_BLKSIZE_BITS;
199 		start %= F2FS_IO_SIZE(sbi);
200 
201 		if (start == 0)
202 			goto submit_io;
203 
204 		/* fill dummy pages */
205 		for (; start < F2FS_IO_SIZE(sbi); start++) {
206 			struct page *page =
207 				mempool_alloc(sbi->write_io_dummy,
208 					GFP_NOIO | __GFP_ZERO | __GFP_NOFAIL);
209 			f2fs_bug_on(sbi, !page);
210 
211 			SetPagePrivate(page);
212 			set_page_private(page, (unsigned long)DUMMY_WRITTEN_PAGE);
213 			lock_page(page);
214 			if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE)
215 				f2fs_bug_on(sbi, 1);
216 		}
217 		/*
218 		 * In the NODE case, we lose next block address chain. So, we
219 		 * need to do checkpoint in f2fs_sync_file.
220 		 */
221 		if (type == NODE)
222 			set_sbi_flag(sbi, SBI_NEED_CP);
223 	}
224 submit_io:
225 	if (is_read_io(bio_op(bio)))
226 		trace_f2fs_submit_read_bio(sbi->sb, type, bio);
227 	else
228 		trace_f2fs_submit_write_bio(sbi->sb, type, bio);
229 	submit_bio(bio);
230 }
231 
232 static void __submit_merged_bio(struct f2fs_bio_info *io)
233 {
234 	struct f2fs_io_info *fio = &io->fio;
235 
236 	if (!io->bio)
237 		return;
238 
239 	bio_set_op_attrs(io->bio, fio->op, fio->op_flags);
240 
241 	if (is_read_io(fio->op))
242 		trace_f2fs_prepare_read_bio(io->sbi->sb, fio->type, io->bio);
243 	else
244 		trace_f2fs_prepare_write_bio(io->sbi->sb, fio->type, io->bio);
245 
246 	__submit_bio(io->sbi, io->bio, fio->type);
247 	io->bio = NULL;
248 }
249 
250 static bool __has_merged_page(struct f2fs_bio_info *io,
251 				struct inode *inode, nid_t ino, pgoff_t idx)
252 {
253 	struct bio_vec *bvec;
254 	struct page *target;
255 	int i;
256 
257 	if (!io->bio)
258 		return false;
259 
260 	if (!inode && !ino)
261 		return true;
262 
263 	bio_for_each_segment_all(bvec, io->bio, i) {
264 
265 		if (bvec->bv_page->mapping)
266 			target = bvec->bv_page;
267 		else
268 			target = fscrypt_control_page(bvec->bv_page);
269 
270 		if (idx != target->index)
271 			continue;
272 
273 		if (inode && inode == target->mapping->host)
274 			return true;
275 		if (ino && ino == ino_of_node(target))
276 			return true;
277 	}
278 
279 	return false;
280 }
281 
282 static bool has_merged_page(struct f2fs_sb_info *sbi, struct inode *inode,
283 				nid_t ino, pgoff_t idx, enum page_type type)
284 {
285 	enum page_type btype = PAGE_TYPE_OF_BIO(type);
286 	enum temp_type temp;
287 	struct f2fs_bio_info *io;
288 	bool ret = false;
289 
290 	for (temp = HOT; temp < NR_TEMP_TYPE; temp++) {
291 		io = sbi->write_io[btype] + temp;
292 
293 		down_read(&io->io_rwsem);
294 		ret = __has_merged_page(io, inode, ino, idx);
295 		up_read(&io->io_rwsem);
296 
297 		/* TODO: use HOT temp only for meta pages now. */
298 		if (ret || btype == META)
299 			break;
300 	}
301 	return ret;
302 }
303 
304 static void __f2fs_submit_merged_write(struct f2fs_sb_info *sbi,
305 				enum page_type type, enum temp_type temp)
306 {
307 	enum page_type btype = PAGE_TYPE_OF_BIO(type);
308 	struct f2fs_bio_info *io = sbi->write_io[btype] + temp;
309 
310 	down_write(&io->io_rwsem);
311 
312 	/* change META to META_FLUSH in the checkpoint procedure */
313 	if (type >= META_FLUSH) {
314 		io->fio.type = META_FLUSH;
315 		io->fio.op = REQ_OP_WRITE;
316 		io->fio.op_flags = REQ_META | REQ_PRIO | REQ_SYNC;
317 		if (!test_opt(sbi, NOBARRIER))
318 			io->fio.op_flags |= REQ_PREFLUSH | REQ_FUA;
319 	}
320 	__submit_merged_bio(io);
321 	up_write(&io->io_rwsem);
322 }
323 
324 static void __submit_merged_write_cond(struct f2fs_sb_info *sbi,
325 				struct inode *inode, nid_t ino, pgoff_t idx,
326 				enum page_type type, bool force)
327 {
328 	enum temp_type temp;
329 
330 	if (!force && !has_merged_page(sbi, inode, ino, idx, type))
331 		return;
332 
333 	for (temp = HOT; temp < NR_TEMP_TYPE; temp++) {
334 
335 		__f2fs_submit_merged_write(sbi, type, temp);
336 
337 		/* TODO: use HOT temp only for meta pages now. */
338 		if (type >= META)
339 			break;
340 	}
341 }
342 
343 void f2fs_submit_merged_write(struct f2fs_sb_info *sbi, enum page_type type)
344 {
345 	__submit_merged_write_cond(sbi, NULL, 0, 0, type, true);
346 }
347 
348 void f2fs_submit_merged_write_cond(struct f2fs_sb_info *sbi,
349 				struct inode *inode, nid_t ino, pgoff_t idx,
350 				enum page_type type)
351 {
352 	__submit_merged_write_cond(sbi, inode, ino, idx, type, false);
353 }
354 
355 void f2fs_flush_merged_writes(struct f2fs_sb_info *sbi)
356 {
357 	f2fs_submit_merged_write(sbi, DATA);
358 	f2fs_submit_merged_write(sbi, NODE);
359 	f2fs_submit_merged_write(sbi, META);
360 }
361 
362 /*
363  * Fill the locked page with data located in the block address.
364  * A caller needs to unlock the page on failure.
365  */
366 int f2fs_submit_page_bio(struct f2fs_io_info *fio)
367 {
368 	struct bio *bio;
369 	struct page *page = fio->encrypted_page ?
370 			fio->encrypted_page : fio->page;
371 
372 	trace_f2fs_submit_page_bio(page, fio);
373 	f2fs_trace_ios(fio, 0);
374 
375 	/* Allocate a new bio */
376 	bio = __bio_alloc(fio->sbi, fio->new_blkaddr, 1, is_read_io(fio->op));
377 
378 	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
379 		bio_put(bio);
380 		return -EFAULT;
381 	}
382 	bio_set_op_attrs(bio, fio->op, fio->op_flags);
383 
384 	__submit_bio(fio->sbi, bio, fio->type);
385 
386 	if (!is_read_io(fio->op))
387 		inc_page_count(fio->sbi, WB_DATA_TYPE(fio->page));
388 	return 0;
389 }
390 
391 int f2fs_submit_page_write(struct f2fs_io_info *fio)
392 {
393 	struct f2fs_sb_info *sbi = fio->sbi;
394 	enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);
395 	struct f2fs_bio_info *io = sbi->write_io[btype] + fio->temp;
396 	struct page *bio_page;
397 	int err = 0;
398 
399 	f2fs_bug_on(sbi, is_read_io(fio->op));
400 
401 	down_write(&io->io_rwsem);
402 next:
403 	if (fio->in_list) {
404 		spin_lock(&io->io_lock);
405 		if (list_empty(&io->io_list)) {
406 			spin_unlock(&io->io_lock);
407 			goto out_fail;
408 		}
409 		fio = list_first_entry(&io->io_list,
410 						struct f2fs_io_info, list);
411 		list_del(&fio->list);
412 		spin_unlock(&io->io_lock);
413 	}
414 
415 	if (fio->old_blkaddr != NEW_ADDR)
416 		verify_block_addr(sbi, fio->old_blkaddr);
417 	verify_block_addr(sbi, fio->new_blkaddr);
418 
419 	bio_page = fio->encrypted_page ? fio->encrypted_page : fio->page;
420 
421 	/* set submitted = true as a return value */
422 	fio->submitted = true;
423 
424 	inc_page_count(sbi, WB_DATA_TYPE(bio_page));
425 
426 	if (io->bio && (io->last_block_in_bio != fio->new_blkaddr - 1 ||
427 	    (io->fio.op != fio->op || io->fio.op_flags != fio->op_flags) ||
428 			!__same_bdev(sbi, fio->new_blkaddr, io->bio)))
429 		__submit_merged_bio(io);
430 alloc_new:
431 	if (io->bio == NULL) {
432 		if ((fio->type == DATA || fio->type == NODE) &&
433 				fio->new_blkaddr & F2FS_IO_SIZE_MASK(sbi)) {
434 			err = -EAGAIN;
435 			dec_page_count(sbi, WB_DATA_TYPE(bio_page));
436 			goto out_fail;
437 		}
438 		io->bio = __bio_alloc(sbi, fio->new_blkaddr,
439 						BIO_MAX_PAGES, false);
440 		io->fio = *fio;
441 	}
442 
443 	if (bio_add_page(io->bio, bio_page, PAGE_SIZE, 0) < PAGE_SIZE) {
444 		__submit_merged_bio(io);
445 		goto alloc_new;
446 	}
447 
448 	io->last_block_in_bio = fio->new_blkaddr;
449 	f2fs_trace_ios(fio, 0);
450 
451 	trace_f2fs_submit_page_write(fio->page, fio);
452 
453 	if (fio->in_list)
454 		goto next;
455 out_fail:
456 	up_write(&io->io_rwsem);
457 	return err;
458 }
459 
460 static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
461 							 unsigned nr_pages)
462 {
463 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
464 	struct fscrypt_ctx *ctx = NULL;
465 	struct bio *bio;
466 
467 	if (f2fs_encrypted_file(inode)) {
468 		ctx = fscrypt_get_ctx(inode, GFP_NOFS);
469 		if (IS_ERR(ctx))
470 			return ERR_CAST(ctx);
471 
472 		/* wait the page to be moved by cleaning */
473 		f2fs_wait_on_block_writeback(sbi, blkaddr);
474 	}
475 
476 	bio = f2fs_bio_alloc(sbi, min_t(int, nr_pages, BIO_MAX_PAGES), false);
477 	if (!bio) {
478 		if (ctx)
479 			fscrypt_release_ctx(ctx);
480 		return ERR_PTR(-ENOMEM);
481 	}
482 	f2fs_target_device(sbi, blkaddr, bio);
483 	bio->bi_end_io = f2fs_read_end_io;
484 	bio->bi_private = ctx;
485 	bio_set_op_attrs(bio, REQ_OP_READ, 0);
486 
487 	return bio;
488 }
489 
490 /* This can handle encryption stuffs */
491 static int f2fs_submit_page_read(struct inode *inode, struct page *page,
492 							block_t blkaddr)
493 {
494 	struct bio *bio = f2fs_grab_read_bio(inode, blkaddr, 1);
495 
496 	if (IS_ERR(bio))
497 		return PTR_ERR(bio);
498 
499 	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
500 		bio_put(bio);
501 		return -EFAULT;
502 	}
503 	__submit_bio(F2FS_I_SB(inode), bio, DATA);
504 	return 0;
505 }
506 
507 static void __set_data_blkaddr(struct dnode_of_data *dn)
508 {
509 	struct f2fs_node *rn = F2FS_NODE(dn->node_page);
510 	__le32 *addr_array;
511 	int base = 0;
512 
513 	if (IS_INODE(dn->node_page) && f2fs_has_extra_attr(dn->inode))
514 		base = get_extra_isize(dn->inode);
515 
516 	/* Get physical address of data block */
517 	addr_array = blkaddr_in_node(rn);
518 	addr_array[base + dn->ofs_in_node] = cpu_to_le32(dn->data_blkaddr);
519 }
520 
521 /*
522  * Lock ordering for the change of data block address:
523  * ->data_page
524  *  ->node_page
525  *    update block addresses in the node page
526  */
527 void set_data_blkaddr(struct dnode_of_data *dn)
528 {
529 	f2fs_wait_on_page_writeback(dn->node_page, NODE, true);
530 	__set_data_blkaddr(dn);
531 	if (set_page_dirty(dn->node_page))
532 		dn->node_changed = true;
533 }
534 
535 void f2fs_update_data_blkaddr(struct dnode_of_data *dn, block_t blkaddr)
536 {
537 	dn->data_blkaddr = blkaddr;
538 	set_data_blkaddr(dn);
539 	f2fs_update_extent_cache(dn);
540 }
541 
542 /* dn->ofs_in_node will be returned with up-to-date last block pointer */
543 int reserve_new_blocks(struct dnode_of_data *dn, blkcnt_t count)
544 {
545 	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
546 	int err;
547 
548 	if (!count)
549 		return 0;
550 
551 	if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC)))
552 		return -EPERM;
553 	if (unlikely((err = inc_valid_block_count(sbi, dn->inode, &count))))
554 		return err;
555 
556 	trace_f2fs_reserve_new_blocks(dn->inode, dn->nid,
557 						dn->ofs_in_node, count);
558 
559 	f2fs_wait_on_page_writeback(dn->node_page, NODE, true);
560 
561 	for (; count > 0; dn->ofs_in_node++) {
562 		block_t blkaddr = datablock_addr(dn->inode,
563 					dn->node_page, dn->ofs_in_node);
564 		if (blkaddr == NULL_ADDR) {
565 			dn->data_blkaddr = NEW_ADDR;
566 			__set_data_blkaddr(dn);
567 			count--;
568 		}
569 	}
570 
571 	if (set_page_dirty(dn->node_page))
572 		dn->node_changed = true;
573 	return 0;
574 }
575 
576 /* Should keep dn->ofs_in_node unchanged */
577 int reserve_new_block(struct dnode_of_data *dn)
578 {
579 	unsigned int ofs_in_node = dn->ofs_in_node;
580 	int ret;
581 
582 	ret = reserve_new_blocks(dn, 1);
583 	dn->ofs_in_node = ofs_in_node;
584 	return ret;
585 }
586 
587 int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index)
588 {
589 	bool need_put = dn->inode_page ? false : true;
590 	int err;
591 
592 	err = get_dnode_of_data(dn, index, ALLOC_NODE);
593 	if (err)
594 		return err;
595 
596 	if (dn->data_blkaddr == NULL_ADDR)
597 		err = reserve_new_block(dn);
598 	if (err || need_put)
599 		f2fs_put_dnode(dn);
600 	return err;
601 }
602 
603 int f2fs_get_block(struct dnode_of_data *dn, pgoff_t index)
604 {
605 	struct extent_info ei  = {0,0,0};
606 	struct inode *inode = dn->inode;
607 
608 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
609 		dn->data_blkaddr = ei.blk + index - ei.fofs;
610 		return 0;
611 	}
612 
613 	return f2fs_reserve_block(dn, index);
614 }
615 
616 struct page *get_read_data_page(struct inode *inode, pgoff_t index,
617 						int op_flags, bool for_write)
618 {
619 	struct address_space *mapping = inode->i_mapping;
620 	struct dnode_of_data dn;
621 	struct page *page;
622 	struct extent_info ei = {0,0,0};
623 	int err;
624 
625 	page = f2fs_grab_cache_page(mapping, index, for_write);
626 	if (!page)
627 		return ERR_PTR(-ENOMEM);
628 
629 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
630 		dn.data_blkaddr = ei.blk + index - ei.fofs;
631 		goto got_it;
632 	}
633 
634 	set_new_dnode(&dn, inode, NULL, NULL, 0);
635 	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
636 	if (err)
637 		goto put_err;
638 	f2fs_put_dnode(&dn);
639 
640 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
641 		err = -ENOENT;
642 		goto put_err;
643 	}
644 got_it:
645 	if (PageUptodate(page)) {
646 		unlock_page(page);
647 		return page;
648 	}
649 
650 	/*
651 	 * A new dentry page is allocated but not able to be written, since its
652 	 * new inode page couldn't be allocated due to -ENOSPC.
653 	 * In such the case, its blkaddr can be remained as NEW_ADDR.
654 	 * see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
655 	 */
656 	if (dn.data_blkaddr == NEW_ADDR) {
657 		zero_user_segment(page, 0, PAGE_SIZE);
658 		if (!PageUptodate(page))
659 			SetPageUptodate(page);
660 		unlock_page(page);
661 		return page;
662 	}
663 
664 	err = f2fs_submit_page_read(inode, page, dn.data_blkaddr);
665 	if (err)
666 		goto put_err;
667 	return page;
668 
669 put_err:
670 	f2fs_put_page(page, 1);
671 	return ERR_PTR(err);
672 }
673 
674 struct page *find_data_page(struct inode *inode, pgoff_t index)
675 {
676 	struct address_space *mapping = inode->i_mapping;
677 	struct page *page;
678 
679 	page = find_get_page(mapping, index);
680 	if (page && PageUptodate(page))
681 		return page;
682 	f2fs_put_page(page, 0);
683 
684 	page = get_read_data_page(inode, index, 0, false);
685 	if (IS_ERR(page))
686 		return page;
687 
688 	if (PageUptodate(page))
689 		return page;
690 
691 	wait_on_page_locked(page);
692 	if (unlikely(!PageUptodate(page))) {
693 		f2fs_put_page(page, 0);
694 		return ERR_PTR(-EIO);
695 	}
696 	return page;
697 }
698 
699 /*
700  * If it tries to access a hole, return an error.
701  * Because, the callers, functions in dir.c and GC, should be able to know
702  * whether this page exists or not.
703  */
704 struct page *get_lock_data_page(struct inode *inode, pgoff_t index,
705 							bool for_write)
706 {
707 	struct address_space *mapping = inode->i_mapping;
708 	struct page *page;
709 repeat:
710 	page = get_read_data_page(inode, index, 0, for_write);
711 	if (IS_ERR(page))
712 		return page;
713 
714 	/* wait for read completion */
715 	lock_page(page);
716 	if (unlikely(page->mapping != mapping)) {
717 		f2fs_put_page(page, 1);
718 		goto repeat;
719 	}
720 	if (unlikely(!PageUptodate(page))) {
721 		f2fs_put_page(page, 1);
722 		return ERR_PTR(-EIO);
723 	}
724 	return page;
725 }
726 
727 /*
728  * Caller ensures that this data page is never allocated.
729  * A new zero-filled data page is allocated in the page cache.
730  *
731  * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
732  * f2fs_unlock_op().
733  * Note that, ipage is set only by make_empty_dir, and if any error occur,
734  * ipage should be released by this function.
735  */
736 struct page *get_new_data_page(struct inode *inode,
737 		struct page *ipage, pgoff_t index, bool new_i_size)
738 {
739 	struct address_space *mapping = inode->i_mapping;
740 	struct page *page;
741 	struct dnode_of_data dn;
742 	int err;
743 
744 	page = f2fs_grab_cache_page(mapping, index, true);
745 	if (!page) {
746 		/*
747 		 * before exiting, we should make sure ipage will be released
748 		 * if any error occur.
749 		 */
750 		f2fs_put_page(ipage, 1);
751 		return ERR_PTR(-ENOMEM);
752 	}
753 
754 	set_new_dnode(&dn, inode, ipage, NULL, 0);
755 	err = f2fs_reserve_block(&dn, index);
756 	if (err) {
757 		f2fs_put_page(page, 1);
758 		return ERR_PTR(err);
759 	}
760 	if (!ipage)
761 		f2fs_put_dnode(&dn);
762 
763 	if (PageUptodate(page))
764 		goto got_it;
765 
766 	if (dn.data_blkaddr == NEW_ADDR) {
767 		zero_user_segment(page, 0, PAGE_SIZE);
768 		if (!PageUptodate(page))
769 			SetPageUptodate(page);
770 	} else {
771 		f2fs_put_page(page, 1);
772 
773 		/* if ipage exists, blkaddr should be NEW_ADDR */
774 		f2fs_bug_on(F2FS_I_SB(inode), ipage);
775 		page = get_lock_data_page(inode, index, true);
776 		if (IS_ERR(page))
777 			return page;
778 	}
779 got_it:
780 	if (new_i_size && i_size_read(inode) <
781 				((loff_t)(index + 1) << PAGE_SHIFT))
782 		f2fs_i_size_write(inode, ((loff_t)(index + 1) << PAGE_SHIFT));
783 	return page;
784 }
785 
786 static int __allocate_data_block(struct dnode_of_data *dn)
787 {
788 	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
789 	struct f2fs_summary sum;
790 	struct node_info ni;
791 	pgoff_t fofs;
792 	blkcnt_t count = 1;
793 	int err;
794 
795 	if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC)))
796 		return -EPERM;
797 
798 	dn->data_blkaddr = datablock_addr(dn->inode,
799 				dn->node_page, dn->ofs_in_node);
800 	if (dn->data_blkaddr == NEW_ADDR)
801 		goto alloc;
802 
803 	if (unlikely((err = inc_valid_block_count(sbi, dn->inode, &count))))
804 		return err;
805 
806 alloc:
807 	get_node_info(sbi, dn->nid, &ni);
808 	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
809 
810 	allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr,
811 					&sum, CURSEG_WARM_DATA, NULL, false);
812 	set_data_blkaddr(dn);
813 
814 	/* update i_size */
815 	fofs = start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
816 							dn->ofs_in_node;
817 	if (i_size_read(dn->inode) < ((loff_t)(fofs + 1) << PAGE_SHIFT))
818 		f2fs_i_size_write(dn->inode,
819 				((loff_t)(fofs + 1) << PAGE_SHIFT));
820 	return 0;
821 }
822 
823 static inline bool __force_buffered_io(struct inode *inode, int rw)
824 {
825 	return (f2fs_encrypted_file(inode) ||
826 			(rw == WRITE && test_opt(F2FS_I_SB(inode), LFS)) ||
827 			F2FS_I_SB(inode)->s_ndevs);
828 }
829 
830 int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)
831 {
832 	struct inode *inode = file_inode(iocb->ki_filp);
833 	struct f2fs_map_blocks map;
834 	int err = 0;
835 
836 	/* convert inline data for Direct I/O*/
837 	if (iocb->ki_flags & IOCB_DIRECT) {
838 		err = f2fs_convert_inline_inode(inode);
839 		if (err)
840 			return err;
841 	}
842 
843 	if (is_inode_flag_set(inode, FI_NO_PREALLOC))
844 		return 0;
845 
846 	map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos);
847 	map.m_len = F2FS_BYTES_TO_BLK(iocb->ki_pos + iov_iter_count(from));
848 	if (map.m_len > map.m_lblk)
849 		map.m_len -= map.m_lblk;
850 	else
851 		map.m_len = 0;
852 
853 	map.m_next_pgofs = NULL;
854 
855 	if (iocb->ki_flags & IOCB_DIRECT)
856 		return f2fs_map_blocks(inode, &map, 1,
857 			__force_buffered_io(inode, WRITE) ?
858 				F2FS_GET_BLOCK_PRE_AIO :
859 				F2FS_GET_BLOCK_PRE_DIO);
860 	if (iocb->ki_pos + iov_iter_count(from) > MAX_INLINE_DATA(inode)) {
861 		err = f2fs_convert_inline_inode(inode);
862 		if (err)
863 			return err;
864 	}
865 	if (!f2fs_has_inline_data(inode)) {
866 		err = f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_AIO);
867 		if (map.m_len > 0 && err == -ENOSPC) {
868 			set_inode_flag(inode, FI_NO_PREALLOC);
869 			err = 0;
870 		}
871 		return err;
872 	}
873 	return err;
874 }
875 
876 static inline void __do_map_lock(struct f2fs_sb_info *sbi, int flag, bool lock)
877 {
878 	if (flag == F2FS_GET_BLOCK_PRE_AIO) {
879 		if (lock)
880 			down_read(&sbi->node_change);
881 		else
882 			up_read(&sbi->node_change);
883 	} else {
884 		if (lock)
885 			f2fs_lock_op(sbi);
886 		else
887 			f2fs_unlock_op(sbi);
888 	}
889 }
890 
891 /*
892  * f2fs_map_blocks() now supported readahead/bmap/rw direct_IO with
893  * f2fs_map_blocks structure.
894  * If original data blocks are allocated, then give them to blockdev.
895  * Otherwise,
896  *     a. preallocate requested block addresses
897  *     b. do not use extent cache for better performance
898  *     c. give the block addresses to blockdev
899  */
900 int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
901 						int create, int flag)
902 {
903 	unsigned int maxblocks = map->m_len;
904 	struct dnode_of_data dn;
905 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
906 	int mode = create ? ALLOC_NODE : LOOKUP_NODE;
907 	pgoff_t pgofs, end_offset, end;
908 	int err = 0, ofs = 1;
909 	unsigned int ofs_in_node, last_ofs_in_node;
910 	blkcnt_t prealloc;
911 	struct extent_info ei = {0,0,0};
912 	block_t blkaddr;
913 
914 	if (!maxblocks)
915 		return 0;
916 
917 	map->m_len = 0;
918 	map->m_flags = 0;
919 
920 	/* it only supports block size == page size */
921 	pgofs =	(pgoff_t)map->m_lblk;
922 	end = pgofs + maxblocks;
923 
924 	if (!create && f2fs_lookup_extent_cache(inode, pgofs, &ei)) {
925 		map->m_pblk = ei.blk + pgofs - ei.fofs;
926 		map->m_len = min((pgoff_t)maxblocks, ei.fofs + ei.len - pgofs);
927 		map->m_flags = F2FS_MAP_MAPPED;
928 		goto out;
929 	}
930 
931 next_dnode:
932 	if (create)
933 		__do_map_lock(sbi, flag, true);
934 
935 	/* When reading holes, we need its node page */
936 	set_new_dnode(&dn, inode, NULL, NULL, 0);
937 	err = get_dnode_of_data(&dn, pgofs, mode);
938 	if (err) {
939 		if (flag == F2FS_GET_BLOCK_BMAP)
940 			map->m_pblk = 0;
941 		if (err == -ENOENT) {
942 			err = 0;
943 			if (map->m_next_pgofs)
944 				*map->m_next_pgofs =
945 					get_next_page_offset(&dn, pgofs);
946 		}
947 		goto unlock_out;
948 	}
949 
950 	prealloc = 0;
951 	last_ofs_in_node = ofs_in_node = dn.ofs_in_node;
952 	end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
953 
954 next_block:
955 	blkaddr = datablock_addr(dn.inode, dn.node_page, dn.ofs_in_node);
956 
957 	if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR) {
958 		if (create) {
959 			if (unlikely(f2fs_cp_error(sbi))) {
960 				err = -EIO;
961 				goto sync_out;
962 			}
963 			if (flag == F2FS_GET_BLOCK_PRE_AIO) {
964 				if (blkaddr == NULL_ADDR) {
965 					prealloc++;
966 					last_ofs_in_node = dn.ofs_in_node;
967 				}
968 			} else {
969 				err = __allocate_data_block(&dn);
970 				if (!err)
971 					set_inode_flag(inode, FI_APPEND_WRITE);
972 			}
973 			if (err)
974 				goto sync_out;
975 			map->m_flags |= F2FS_MAP_NEW;
976 			blkaddr = dn.data_blkaddr;
977 		} else {
978 			if (flag == F2FS_GET_BLOCK_BMAP) {
979 				map->m_pblk = 0;
980 				goto sync_out;
981 			}
982 			if (flag == F2FS_GET_BLOCK_FIEMAP &&
983 						blkaddr == NULL_ADDR) {
984 				if (map->m_next_pgofs)
985 					*map->m_next_pgofs = pgofs + 1;
986 			}
987 			if (flag != F2FS_GET_BLOCK_FIEMAP ||
988 						blkaddr != NEW_ADDR)
989 				goto sync_out;
990 		}
991 	}
992 
993 	if (flag == F2FS_GET_BLOCK_PRE_AIO)
994 		goto skip;
995 
996 	if (map->m_len == 0) {
997 		/* preallocated unwritten block should be mapped for fiemap. */
998 		if (blkaddr == NEW_ADDR)
999 			map->m_flags |= F2FS_MAP_UNWRITTEN;
1000 		map->m_flags |= F2FS_MAP_MAPPED;
1001 
1002 		map->m_pblk = blkaddr;
1003 		map->m_len = 1;
1004 	} else if ((map->m_pblk != NEW_ADDR &&
1005 			blkaddr == (map->m_pblk + ofs)) ||
1006 			(map->m_pblk == NEW_ADDR && blkaddr == NEW_ADDR) ||
1007 			flag == F2FS_GET_BLOCK_PRE_DIO) {
1008 		ofs++;
1009 		map->m_len++;
1010 	} else {
1011 		goto sync_out;
1012 	}
1013 
1014 skip:
1015 	dn.ofs_in_node++;
1016 	pgofs++;
1017 
1018 	/* preallocate blocks in batch for one dnode page */
1019 	if (flag == F2FS_GET_BLOCK_PRE_AIO &&
1020 			(pgofs == end || dn.ofs_in_node == end_offset)) {
1021 
1022 		dn.ofs_in_node = ofs_in_node;
1023 		err = reserve_new_blocks(&dn, prealloc);
1024 		if (err)
1025 			goto sync_out;
1026 
1027 		map->m_len += dn.ofs_in_node - ofs_in_node;
1028 		if (prealloc && dn.ofs_in_node != last_ofs_in_node + 1) {
1029 			err = -ENOSPC;
1030 			goto sync_out;
1031 		}
1032 		dn.ofs_in_node = end_offset;
1033 	}
1034 
1035 	if (pgofs >= end)
1036 		goto sync_out;
1037 	else if (dn.ofs_in_node < end_offset)
1038 		goto next_block;
1039 
1040 	f2fs_put_dnode(&dn);
1041 
1042 	if (create) {
1043 		__do_map_lock(sbi, flag, false);
1044 		f2fs_balance_fs(sbi, dn.node_changed);
1045 	}
1046 	goto next_dnode;
1047 
1048 sync_out:
1049 	f2fs_put_dnode(&dn);
1050 unlock_out:
1051 	if (create) {
1052 		__do_map_lock(sbi, flag, false);
1053 		f2fs_balance_fs(sbi, dn.node_changed);
1054 	}
1055 out:
1056 	trace_f2fs_map_blocks(inode, map, err);
1057 	return err;
1058 }
1059 
1060 static int __get_data_block(struct inode *inode, sector_t iblock,
1061 			struct buffer_head *bh, int create, int flag,
1062 			pgoff_t *next_pgofs)
1063 {
1064 	struct f2fs_map_blocks map;
1065 	int err;
1066 
1067 	map.m_lblk = iblock;
1068 	map.m_len = bh->b_size >> inode->i_blkbits;
1069 	map.m_next_pgofs = next_pgofs;
1070 
1071 	err = f2fs_map_blocks(inode, &map, create, flag);
1072 	if (!err) {
1073 		map_bh(bh, inode->i_sb, map.m_pblk);
1074 		bh->b_state = (bh->b_state & ~F2FS_MAP_FLAGS) | map.m_flags;
1075 		bh->b_size = (u64)map.m_len << inode->i_blkbits;
1076 	}
1077 	return err;
1078 }
1079 
1080 static int get_data_block(struct inode *inode, sector_t iblock,
1081 			struct buffer_head *bh_result, int create, int flag,
1082 			pgoff_t *next_pgofs)
1083 {
1084 	return __get_data_block(inode, iblock, bh_result, create,
1085 							flag, next_pgofs);
1086 }
1087 
1088 static int get_data_block_dio(struct inode *inode, sector_t iblock,
1089 			struct buffer_head *bh_result, int create)
1090 {
1091 	return __get_data_block(inode, iblock, bh_result, create,
1092 						F2FS_GET_BLOCK_DEFAULT, NULL);
1093 }
1094 
1095 static int get_data_block_bmap(struct inode *inode, sector_t iblock,
1096 			struct buffer_head *bh_result, int create)
1097 {
1098 	/* Block number less than F2FS MAX BLOCKS */
1099 	if (unlikely(iblock >= F2FS_I_SB(inode)->max_file_blocks))
1100 		return -EFBIG;
1101 
1102 	return __get_data_block(inode, iblock, bh_result, create,
1103 						F2FS_GET_BLOCK_BMAP, NULL);
1104 }
1105 
1106 static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
1107 {
1108 	return (offset >> inode->i_blkbits);
1109 }
1110 
1111 static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)
1112 {
1113 	return (blk << inode->i_blkbits);
1114 }
1115 
1116 int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
1117 		u64 start, u64 len)
1118 {
1119 	struct buffer_head map_bh;
1120 	sector_t start_blk, last_blk;
1121 	pgoff_t next_pgofs;
1122 	u64 logical = 0, phys = 0, size = 0;
1123 	u32 flags = 0;
1124 	int ret = 0;
1125 
1126 	ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
1127 	if (ret)
1128 		return ret;
1129 
1130 	if (f2fs_has_inline_data(inode)) {
1131 		ret = f2fs_inline_data_fiemap(inode, fieinfo, start, len);
1132 		if (ret != -EAGAIN)
1133 			return ret;
1134 	}
1135 
1136 	inode_lock(inode);
1137 
1138 	if (logical_to_blk(inode, len) == 0)
1139 		len = blk_to_logical(inode, 1);
1140 
1141 	start_blk = logical_to_blk(inode, start);
1142 	last_blk = logical_to_blk(inode, start + len - 1);
1143 
1144 next:
1145 	memset(&map_bh, 0, sizeof(struct buffer_head));
1146 	map_bh.b_size = len;
1147 
1148 	ret = get_data_block(inode, start_blk, &map_bh, 0,
1149 					F2FS_GET_BLOCK_FIEMAP, &next_pgofs);
1150 	if (ret)
1151 		goto out;
1152 
1153 	/* HOLE */
1154 	if (!buffer_mapped(&map_bh)) {
1155 		start_blk = next_pgofs;
1156 
1157 		if (blk_to_logical(inode, start_blk) < blk_to_logical(inode,
1158 					F2FS_I_SB(inode)->max_file_blocks))
1159 			goto prep_next;
1160 
1161 		flags |= FIEMAP_EXTENT_LAST;
1162 	}
1163 
1164 	if (size) {
1165 		if (f2fs_encrypted_inode(inode))
1166 			flags |= FIEMAP_EXTENT_DATA_ENCRYPTED;
1167 
1168 		ret = fiemap_fill_next_extent(fieinfo, logical,
1169 				phys, size, flags);
1170 	}
1171 
1172 	if (start_blk > last_blk || ret)
1173 		goto out;
1174 
1175 	logical = blk_to_logical(inode, start_blk);
1176 	phys = blk_to_logical(inode, map_bh.b_blocknr);
1177 	size = map_bh.b_size;
1178 	flags = 0;
1179 	if (buffer_unwritten(&map_bh))
1180 		flags = FIEMAP_EXTENT_UNWRITTEN;
1181 
1182 	start_blk += logical_to_blk(inode, size);
1183 
1184 prep_next:
1185 	cond_resched();
1186 	if (fatal_signal_pending(current))
1187 		ret = -EINTR;
1188 	else
1189 		goto next;
1190 out:
1191 	if (ret == 1)
1192 		ret = 0;
1193 
1194 	inode_unlock(inode);
1195 	return ret;
1196 }
1197 
1198 /*
1199  * This function was originally taken from fs/mpage.c, and customized for f2fs.
1200  * Major change was from block_size == page_size in f2fs by default.
1201  */
1202 static int f2fs_mpage_readpages(struct address_space *mapping,
1203 			struct list_head *pages, struct page *page,
1204 			unsigned nr_pages)
1205 {
1206 	struct bio *bio = NULL;
1207 	sector_t last_block_in_bio = 0;
1208 	struct inode *inode = mapping->host;
1209 	const unsigned blkbits = inode->i_blkbits;
1210 	const unsigned blocksize = 1 << blkbits;
1211 	sector_t block_in_file;
1212 	sector_t last_block;
1213 	sector_t last_block_in_file;
1214 	sector_t block_nr;
1215 	struct f2fs_map_blocks map;
1216 
1217 	map.m_pblk = 0;
1218 	map.m_lblk = 0;
1219 	map.m_len = 0;
1220 	map.m_flags = 0;
1221 	map.m_next_pgofs = NULL;
1222 
1223 	for (; nr_pages; nr_pages--) {
1224 		if (pages) {
1225 			page = list_last_entry(pages, struct page, lru);
1226 
1227 			prefetchw(&page->flags);
1228 			list_del(&page->lru);
1229 			if (add_to_page_cache_lru(page, mapping,
1230 						  page->index,
1231 						  readahead_gfp_mask(mapping)))
1232 				goto next_page;
1233 		}
1234 
1235 		block_in_file = (sector_t)page->index;
1236 		last_block = block_in_file + nr_pages;
1237 		last_block_in_file = (i_size_read(inode) + blocksize - 1) >>
1238 								blkbits;
1239 		if (last_block > last_block_in_file)
1240 			last_block = last_block_in_file;
1241 
1242 		/*
1243 		 * Map blocks using the previous result first.
1244 		 */
1245 		if ((map.m_flags & F2FS_MAP_MAPPED) &&
1246 				block_in_file > map.m_lblk &&
1247 				block_in_file < (map.m_lblk + map.m_len))
1248 			goto got_it;
1249 
1250 		/*
1251 		 * Then do more f2fs_map_blocks() calls until we are
1252 		 * done with this page.
1253 		 */
1254 		map.m_flags = 0;
1255 
1256 		if (block_in_file < last_block) {
1257 			map.m_lblk = block_in_file;
1258 			map.m_len = last_block - block_in_file;
1259 
1260 			if (f2fs_map_blocks(inode, &map, 0,
1261 						F2FS_GET_BLOCK_DEFAULT))
1262 				goto set_error_page;
1263 		}
1264 got_it:
1265 		if ((map.m_flags & F2FS_MAP_MAPPED)) {
1266 			block_nr = map.m_pblk + block_in_file - map.m_lblk;
1267 			SetPageMappedToDisk(page);
1268 
1269 			if (!PageUptodate(page) && !cleancache_get_page(page)) {
1270 				SetPageUptodate(page);
1271 				goto confused;
1272 			}
1273 		} else {
1274 			zero_user_segment(page, 0, PAGE_SIZE);
1275 			if (!PageUptodate(page))
1276 				SetPageUptodate(page);
1277 			unlock_page(page);
1278 			goto next_page;
1279 		}
1280 
1281 		/*
1282 		 * This page will go to BIO.  Do we need to send this
1283 		 * BIO off first?
1284 		 */
1285 		if (bio && (last_block_in_bio != block_nr - 1 ||
1286 			!__same_bdev(F2FS_I_SB(inode), block_nr, bio))) {
1287 submit_and_realloc:
1288 			__submit_bio(F2FS_I_SB(inode), bio, DATA);
1289 			bio = NULL;
1290 		}
1291 		if (bio == NULL) {
1292 			bio = f2fs_grab_read_bio(inode, block_nr, nr_pages);
1293 			if (IS_ERR(bio)) {
1294 				bio = NULL;
1295 				goto set_error_page;
1296 			}
1297 		}
1298 
1299 		if (bio_add_page(bio, page, blocksize, 0) < blocksize)
1300 			goto submit_and_realloc;
1301 
1302 		last_block_in_bio = block_nr;
1303 		goto next_page;
1304 set_error_page:
1305 		SetPageError(page);
1306 		zero_user_segment(page, 0, PAGE_SIZE);
1307 		unlock_page(page);
1308 		goto next_page;
1309 confused:
1310 		if (bio) {
1311 			__submit_bio(F2FS_I_SB(inode), bio, DATA);
1312 			bio = NULL;
1313 		}
1314 		unlock_page(page);
1315 next_page:
1316 		if (pages)
1317 			put_page(page);
1318 	}
1319 	BUG_ON(pages && !list_empty(pages));
1320 	if (bio)
1321 		__submit_bio(F2FS_I_SB(inode), bio, DATA);
1322 	return 0;
1323 }
1324 
1325 static int f2fs_read_data_page(struct file *file, struct page *page)
1326 {
1327 	struct inode *inode = page->mapping->host;
1328 	int ret = -EAGAIN;
1329 
1330 	trace_f2fs_readpage(page, DATA);
1331 
1332 	/* If the file has inline data, try to read it directly */
1333 	if (f2fs_has_inline_data(inode))
1334 		ret = f2fs_read_inline_data(inode, page);
1335 	if (ret == -EAGAIN)
1336 		ret = f2fs_mpage_readpages(page->mapping, NULL, page, 1);
1337 	return ret;
1338 }
1339 
1340 static int f2fs_read_data_pages(struct file *file,
1341 			struct address_space *mapping,
1342 			struct list_head *pages, unsigned nr_pages)
1343 {
1344 	struct inode *inode = mapping->host;
1345 	struct page *page = list_last_entry(pages, struct page, lru);
1346 
1347 	trace_f2fs_readpages(inode, page, nr_pages);
1348 
1349 	/* If the file has inline data, skip readpages */
1350 	if (f2fs_has_inline_data(inode))
1351 		return 0;
1352 
1353 	return f2fs_mpage_readpages(mapping, pages, NULL, nr_pages);
1354 }
1355 
1356 static int encrypt_one_page(struct f2fs_io_info *fio)
1357 {
1358 	struct inode *inode = fio->page->mapping->host;
1359 	gfp_t gfp_flags = GFP_NOFS;
1360 
1361 	if (!f2fs_encrypted_file(inode))
1362 		return 0;
1363 
1364 	/* wait for GCed encrypted page writeback */
1365 	f2fs_wait_on_block_writeback(fio->sbi, fio->old_blkaddr);
1366 
1367 retry_encrypt:
1368 	fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
1369 			PAGE_SIZE, 0, fio->page->index, gfp_flags);
1370 	if (!IS_ERR(fio->encrypted_page))
1371 		return 0;
1372 
1373 	/* flush pending IOs and wait for a while in the ENOMEM case */
1374 	if (PTR_ERR(fio->encrypted_page) == -ENOMEM) {
1375 		f2fs_flush_merged_writes(fio->sbi);
1376 		congestion_wait(BLK_RW_ASYNC, HZ/50);
1377 		gfp_flags |= __GFP_NOFAIL;
1378 		goto retry_encrypt;
1379 	}
1380 	return PTR_ERR(fio->encrypted_page);
1381 }
1382 
1383 static inline bool need_inplace_update(struct f2fs_io_info *fio)
1384 {
1385 	struct inode *inode = fio->page->mapping->host;
1386 
1387 	if (S_ISDIR(inode->i_mode) || f2fs_is_atomic_file(inode))
1388 		return false;
1389 	if (is_cold_data(fio->page))
1390 		return false;
1391 	if (IS_ATOMIC_WRITTEN_PAGE(fio->page))
1392 		return false;
1393 
1394 	return need_inplace_update_policy(inode, fio);
1395 }
1396 
1397 static inline bool valid_ipu_blkaddr(struct f2fs_io_info *fio)
1398 {
1399 	if (fio->old_blkaddr == NEW_ADDR)
1400 		return false;
1401 	if (fio->old_blkaddr == NULL_ADDR)
1402 		return false;
1403 	return true;
1404 }
1405 
1406 int do_write_data_page(struct f2fs_io_info *fio)
1407 {
1408 	struct page *page = fio->page;
1409 	struct inode *inode = page->mapping->host;
1410 	struct dnode_of_data dn;
1411 	struct extent_info ei = {0,0,0};
1412 	bool ipu_force = false;
1413 	int err = 0;
1414 
1415 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1416 	if (need_inplace_update(fio) &&
1417 			f2fs_lookup_extent_cache(inode, page->index, &ei)) {
1418 		fio->old_blkaddr = ei.blk + page->index - ei.fofs;
1419 
1420 		if (valid_ipu_blkaddr(fio)) {
1421 			ipu_force = true;
1422 			fio->need_lock = LOCK_DONE;
1423 			goto got_it;
1424 		}
1425 	}
1426 
1427 	/* Deadlock due to between page->lock and f2fs_lock_op */
1428 	if (fio->need_lock == LOCK_REQ && !f2fs_trylock_op(fio->sbi))
1429 		return -EAGAIN;
1430 
1431 	err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
1432 	if (err)
1433 		goto out;
1434 
1435 	fio->old_blkaddr = dn.data_blkaddr;
1436 
1437 	/* This page is already truncated */
1438 	if (fio->old_blkaddr == NULL_ADDR) {
1439 		ClearPageUptodate(page);
1440 		goto out_writepage;
1441 	}
1442 got_it:
1443 	/*
1444 	 * If current allocation needs SSR,
1445 	 * it had better in-place writes for updated data.
1446 	 */
1447 	if (ipu_force || (valid_ipu_blkaddr(fio) && need_inplace_update(fio))) {
1448 		err = encrypt_one_page(fio);
1449 		if (err)
1450 			goto out_writepage;
1451 
1452 		set_page_writeback(page);
1453 		f2fs_put_dnode(&dn);
1454 		if (fio->need_lock == LOCK_REQ)
1455 			f2fs_unlock_op(fio->sbi);
1456 		err = rewrite_data_page(fio);
1457 		trace_f2fs_do_write_data_page(fio->page, IPU);
1458 		set_inode_flag(inode, FI_UPDATE_WRITE);
1459 		return err;
1460 	}
1461 
1462 	if (fio->need_lock == LOCK_RETRY) {
1463 		if (!f2fs_trylock_op(fio->sbi)) {
1464 			err = -EAGAIN;
1465 			goto out_writepage;
1466 		}
1467 		fio->need_lock = LOCK_REQ;
1468 	}
1469 
1470 	err = encrypt_one_page(fio);
1471 	if (err)
1472 		goto out_writepage;
1473 
1474 	set_page_writeback(page);
1475 
1476 	/* LFS mode write path */
1477 	write_data_page(&dn, fio);
1478 	trace_f2fs_do_write_data_page(page, OPU);
1479 	set_inode_flag(inode, FI_APPEND_WRITE);
1480 	if (page->index == 0)
1481 		set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
1482 out_writepage:
1483 	f2fs_put_dnode(&dn);
1484 out:
1485 	if (fio->need_lock == LOCK_REQ)
1486 		f2fs_unlock_op(fio->sbi);
1487 	return err;
1488 }
1489 
1490 static int __write_data_page(struct page *page, bool *submitted,
1491 				struct writeback_control *wbc,
1492 				enum iostat_type io_type)
1493 {
1494 	struct inode *inode = page->mapping->host;
1495 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1496 	loff_t i_size = i_size_read(inode);
1497 	const pgoff_t end_index = ((unsigned long long) i_size)
1498 							>> PAGE_SHIFT;
1499 	loff_t psize = (page->index + 1) << PAGE_SHIFT;
1500 	unsigned offset = 0;
1501 	bool need_balance_fs = false;
1502 	int err = 0;
1503 	struct f2fs_io_info fio = {
1504 		.sbi = sbi,
1505 		.ino = inode->i_ino,
1506 		.type = DATA,
1507 		.op = REQ_OP_WRITE,
1508 		.op_flags = wbc_to_write_flags(wbc),
1509 		.old_blkaddr = NULL_ADDR,
1510 		.page = page,
1511 		.encrypted_page = NULL,
1512 		.submitted = false,
1513 		.need_lock = LOCK_RETRY,
1514 		.io_type = io_type,
1515 	};
1516 
1517 	trace_f2fs_writepage(page, DATA);
1518 
1519 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
1520 		goto redirty_out;
1521 
1522 	if (page->index < end_index)
1523 		goto write;
1524 
1525 	/*
1526 	 * If the offset is out-of-range of file size,
1527 	 * this page does not have to be written to disk.
1528 	 */
1529 	offset = i_size & (PAGE_SIZE - 1);
1530 	if ((page->index >= end_index + 1) || !offset)
1531 		goto out;
1532 
1533 	zero_user_segment(page, offset, PAGE_SIZE);
1534 write:
1535 	if (f2fs_is_drop_cache(inode))
1536 		goto out;
1537 	/* we should not write 0'th page having journal header */
1538 	if (f2fs_is_volatile_file(inode) && (!page->index ||
1539 			(!wbc->for_reclaim &&
1540 			available_free_memory(sbi, BASE_CHECK))))
1541 		goto redirty_out;
1542 
1543 	/* we should bypass data pages to proceed the kworkder jobs */
1544 	if (unlikely(f2fs_cp_error(sbi))) {
1545 		mapping_set_error(page->mapping, -EIO);
1546 		goto out;
1547 	}
1548 
1549 	/* Dentry blocks are controlled by checkpoint */
1550 	if (S_ISDIR(inode->i_mode)) {
1551 		fio.need_lock = LOCK_DONE;
1552 		err = do_write_data_page(&fio);
1553 		goto done;
1554 	}
1555 
1556 	if (!wbc->for_reclaim)
1557 		need_balance_fs = true;
1558 	else if (has_not_enough_free_secs(sbi, 0, 0))
1559 		goto redirty_out;
1560 	else
1561 		set_inode_flag(inode, FI_HOT_DATA);
1562 
1563 	err = -EAGAIN;
1564 	if (f2fs_has_inline_data(inode)) {
1565 		err = f2fs_write_inline_data(inode, page);
1566 		if (!err)
1567 			goto out;
1568 	}
1569 
1570 	if (err == -EAGAIN) {
1571 		err = do_write_data_page(&fio);
1572 		if (err == -EAGAIN) {
1573 			fio.need_lock = LOCK_REQ;
1574 			err = do_write_data_page(&fio);
1575 		}
1576 	}
1577 
1578 	down_write(&F2FS_I(inode)->i_sem);
1579 	if (F2FS_I(inode)->last_disk_size < psize)
1580 		F2FS_I(inode)->last_disk_size = psize;
1581 	up_write(&F2FS_I(inode)->i_sem);
1582 
1583 done:
1584 	if (err && err != -ENOENT)
1585 		goto redirty_out;
1586 
1587 out:
1588 	inode_dec_dirty_pages(inode);
1589 	if (err)
1590 		ClearPageUptodate(page);
1591 
1592 	if (wbc->for_reclaim) {
1593 		f2fs_submit_merged_write_cond(sbi, inode, 0, page->index, DATA);
1594 		clear_inode_flag(inode, FI_HOT_DATA);
1595 		remove_dirty_inode(inode);
1596 		submitted = NULL;
1597 	}
1598 
1599 	unlock_page(page);
1600 	if (!S_ISDIR(inode->i_mode))
1601 		f2fs_balance_fs(sbi, need_balance_fs);
1602 
1603 	if (unlikely(f2fs_cp_error(sbi))) {
1604 		f2fs_submit_merged_write(sbi, DATA);
1605 		submitted = NULL;
1606 	}
1607 
1608 	if (submitted)
1609 		*submitted = fio.submitted;
1610 
1611 	return 0;
1612 
1613 redirty_out:
1614 	redirty_page_for_writepage(wbc, page);
1615 	if (!err)
1616 		return AOP_WRITEPAGE_ACTIVATE;
1617 	unlock_page(page);
1618 	return err;
1619 }
1620 
1621 static int f2fs_write_data_page(struct page *page,
1622 					struct writeback_control *wbc)
1623 {
1624 	return __write_data_page(page, NULL, wbc, FS_DATA_IO);
1625 }
1626 
1627 /*
1628  * This function was copied from write_cche_pages from mm/page-writeback.c.
1629  * The major change is making write step of cold data page separately from
1630  * warm/hot data page.
1631  */
1632 static int f2fs_write_cache_pages(struct address_space *mapping,
1633 					struct writeback_control *wbc,
1634 					enum iostat_type io_type)
1635 {
1636 	int ret = 0;
1637 	int done = 0;
1638 	struct pagevec pvec;
1639 	int nr_pages;
1640 	pgoff_t uninitialized_var(writeback_index);
1641 	pgoff_t index;
1642 	pgoff_t end;		/* Inclusive */
1643 	pgoff_t done_index;
1644 	pgoff_t last_idx = ULONG_MAX;
1645 	int cycled;
1646 	int range_whole = 0;
1647 	int tag;
1648 
1649 	pagevec_init(&pvec);
1650 
1651 	if (get_dirty_pages(mapping->host) <=
1652 				SM_I(F2FS_M_SB(mapping))->min_hot_blocks)
1653 		set_inode_flag(mapping->host, FI_HOT_DATA);
1654 	else
1655 		clear_inode_flag(mapping->host, FI_HOT_DATA);
1656 
1657 	if (wbc->range_cyclic) {
1658 		writeback_index = mapping->writeback_index; /* prev offset */
1659 		index = writeback_index;
1660 		if (index == 0)
1661 			cycled = 1;
1662 		else
1663 			cycled = 0;
1664 		end = -1;
1665 	} else {
1666 		index = wbc->range_start >> PAGE_SHIFT;
1667 		end = wbc->range_end >> PAGE_SHIFT;
1668 		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
1669 			range_whole = 1;
1670 		cycled = 1; /* ignore range_cyclic tests */
1671 	}
1672 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
1673 		tag = PAGECACHE_TAG_TOWRITE;
1674 	else
1675 		tag = PAGECACHE_TAG_DIRTY;
1676 retry:
1677 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
1678 		tag_pages_for_writeback(mapping, index, end);
1679 	done_index = index;
1680 	while (!done && (index <= end)) {
1681 		int i;
1682 
1683 		nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index, end,
1684 				tag);
1685 		if (nr_pages == 0)
1686 			break;
1687 
1688 		for (i = 0; i < nr_pages; i++) {
1689 			struct page *page = pvec.pages[i];
1690 			bool submitted = false;
1691 
1692 			done_index = page->index;
1693 retry_write:
1694 			lock_page(page);
1695 
1696 			if (unlikely(page->mapping != mapping)) {
1697 continue_unlock:
1698 				unlock_page(page);
1699 				continue;
1700 			}
1701 
1702 			if (!PageDirty(page)) {
1703 				/* someone wrote it for us */
1704 				goto continue_unlock;
1705 			}
1706 
1707 			if (PageWriteback(page)) {
1708 				if (wbc->sync_mode != WB_SYNC_NONE)
1709 					f2fs_wait_on_page_writeback(page,
1710 								DATA, true);
1711 				else
1712 					goto continue_unlock;
1713 			}
1714 
1715 			BUG_ON(PageWriteback(page));
1716 			if (!clear_page_dirty_for_io(page))
1717 				goto continue_unlock;
1718 
1719 			ret = __write_data_page(page, &submitted, wbc, io_type);
1720 			if (unlikely(ret)) {
1721 				/*
1722 				 * keep nr_to_write, since vfs uses this to
1723 				 * get # of written pages.
1724 				 */
1725 				if (ret == AOP_WRITEPAGE_ACTIVATE) {
1726 					unlock_page(page);
1727 					ret = 0;
1728 					continue;
1729 				} else if (ret == -EAGAIN) {
1730 					ret = 0;
1731 					if (wbc->sync_mode == WB_SYNC_ALL) {
1732 						cond_resched();
1733 						congestion_wait(BLK_RW_ASYNC,
1734 									HZ/50);
1735 						goto retry_write;
1736 					}
1737 					continue;
1738 				}
1739 				done_index = page->index + 1;
1740 				done = 1;
1741 				break;
1742 			} else if (submitted) {
1743 				last_idx = page->index;
1744 			}
1745 
1746 			/* give a priority to WB_SYNC threads */
1747 			if ((atomic_read(&F2FS_M_SB(mapping)->wb_sync_req) ||
1748 					--wbc->nr_to_write <= 0) &&
1749 					wbc->sync_mode == WB_SYNC_NONE) {
1750 				done = 1;
1751 				break;
1752 			}
1753 		}
1754 		pagevec_release(&pvec);
1755 		cond_resched();
1756 	}
1757 
1758 	if (!cycled && !done) {
1759 		cycled = 1;
1760 		index = 0;
1761 		end = writeback_index - 1;
1762 		goto retry;
1763 	}
1764 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1765 		mapping->writeback_index = done_index;
1766 
1767 	if (last_idx != ULONG_MAX)
1768 		f2fs_submit_merged_write_cond(F2FS_M_SB(mapping), mapping->host,
1769 						0, last_idx, DATA);
1770 
1771 	return ret;
1772 }
1773 
1774 int __f2fs_write_data_pages(struct address_space *mapping,
1775 						struct writeback_control *wbc,
1776 						enum iostat_type io_type)
1777 {
1778 	struct inode *inode = mapping->host;
1779 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1780 	struct blk_plug plug;
1781 	int ret;
1782 
1783 	/* deal with chardevs and other special file */
1784 	if (!mapping->a_ops->writepage)
1785 		return 0;
1786 
1787 	/* skip writing if there is no dirty page in this inode */
1788 	if (!get_dirty_pages(inode) && wbc->sync_mode == WB_SYNC_NONE)
1789 		return 0;
1790 
1791 	/* during POR, we don't need to trigger writepage at all. */
1792 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
1793 		goto skip_write;
1794 
1795 	if (S_ISDIR(inode->i_mode) && wbc->sync_mode == WB_SYNC_NONE &&
1796 			get_dirty_pages(inode) < nr_pages_to_skip(sbi, DATA) &&
1797 			available_free_memory(sbi, DIRTY_DENTS))
1798 		goto skip_write;
1799 
1800 	/* skip writing during file defragment */
1801 	if (is_inode_flag_set(inode, FI_DO_DEFRAG))
1802 		goto skip_write;
1803 
1804 	trace_f2fs_writepages(mapping->host, wbc, DATA);
1805 
1806 	/* to avoid spliting IOs due to mixed WB_SYNC_ALL and WB_SYNC_NONE */
1807 	if (wbc->sync_mode == WB_SYNC_ALL)
1808 		atomic_inc(&sbi->wb_sync_req);
1809 	else if (atomic_read(&sbi->wb_sync_req))
1810 		goto skip_write;
1811 
1812 	blk_start_plug(&plug);
1813 	ret = f2fs_write_cache_pages(mapping, wbc, io_type);
1814 	blk_finish_plug(&plug);
1815 
1816 	if (wbc->sync_mode == WB_SYNC_ALL)
1817 		atomic_dec(&sbi->wb_sync_req);
1818 	/*
1819 	 * if some pages were truncated, we cannot guarantee its mapping->host
1820 	 * to detect pending bios.
1821 	 */
1822 
1823 	remove_dirty_inode(inode);
1824 	return ret;
1825 
1826 skip_write:
1827 	wbc->pages_skipped += get_dirty_pages(inode);
1828 	trace_f2fs_writepages(mapping->host, wbc, DATA);
1829 	return 0;
1830 }
1831 
1832 static int f2fs_write_data_pages(struct address_space *mapping,
1833 			    struct writeback_control *wbc)
1834 {
1835 	struct inode *inode = mapping->host;
1836 
1837 	return __f2fs_write_data_pages(mapping, wbc,
1838 			F2FS_I(inode)->cp_task == current ?
1839 			FS_CP_DATA_IO : FS_DATA_IO);
1840 }
1841 
1842 static void f2fs_write_failed(struct address_space *mapping, loff_t to)
1843 {
1844 	struct inode *inode = mapping->host;
1845 	loff_t i_size = i_size_read(inode);
1846 
1847 	if (to > i_size) {
1848 		down_write(&F2FS_I(inode)->i_mmap_sem);
1849 		truncate_pagecache(inode, i_size);
1850 		truncate_blocks(inode, i_size, true);
1851 		up_write(&F2FS_I(inode)->i_mmap_sem);
1852 	}
1853 }
1854 
1855 static int prepare_write_begin(struct f2fs_sb_info *sbi,
1856 			struct page *page, loff_t pos, unsigned len,
1857 			block_t *blk_addr, bool *node_changed)
1858 {
1859 	struct inode *inode = page->mapping->host;
1860 	pgoff_t index = page->index;
1861 	struct dnode_of_data dn;
1862 	struct page *ipage;
1863 	bool locked = false;
1864 	struct extent_info ei = {0,0,0};
1865 	int err = 0;
1866 
1867 	/*
1868 	 * we already allocated all the blocks, so we don't need to get
1869 	 * the block addresses when there is no need to fill the page.
1870 	 */
1871 	if (!f2fs_has_inline_data(inode) && len == PAGE_SIZE &&
1872 			!is_inode_flag_set(inode, FI_NO_PREALLOC))
1873 		return 0;
1874 
1875 	if (f2fs_has_inline_data(inode) ||
1876 			(pos & PAGE_MASK) >= i_size_read(inode)) {
1877 		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
1878 		locked = true;
1879 	}
1880 restart:
1881 	/* check inline_data */
1882 	ipage = get_node_page(sbi, inode->i_ino);
1883 	if (IS_ERR(ipage)) {
1884 		err = PTR_ERR(ipage);
1885 		goto unlock_out;
1886 	}
1887 
1888 	set_new_dnode(&dn, inode, ipage, ipage, 0);
1889 
1890 	if (f2fs_has_inline_data(inode)) {
1891 		if (pos + len <= MAX_INLINE_DATA(inode)) {
1892 			read_inline_data(page, ipage);
1893 			set_inode_flag(inode, FI_DATA_EXIST);
1894 			if (inode->i_nlink)
1895 				set_inline_node(ipage);
1896 		} else {
1897 			err = f2fs_convert_inline_page(&dn, page);
1898 			if (err)
1899 				goto out;
1900 			if (dn.data_blkaddr == NULL_ADDR)
1901 				err = f2fs_get_block(&dn, index);
1902 		}
1903 	} else if (locked) {
1904 		err = f2fs_get_block(&dn, index);
1905 	} else {
1906 		if (f2fs_lookup_extent_cache(inode, index, &ei)) {
1907 			dn.data_blkaddr = ei.blk + index - ei.fofs;
1908 		} else {
1909 			/* hole case */
1910 			err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
1911 			if (err || dn.data_blkaddr == NULL_ADDR) {
1912 				f2fs_put_dnode(&dn);
1913 				__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO,
1914 								true);
1915 				locked = true;
1916 				goto restart;
1917 			}
1918 		}
1919 	}
1920 
1921 	/* convert_inline_page can make node_changed */
1922 	*blk_addr = dn.data_blkaddr;
1923 	*node_changed = dn.node_changed;
1924 out:
1925 	f2fs_put_dnode(&dn);
1926 unlock_out:
1927 	if (locked)
1928 		__do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
1929 	return err;
1930 }
1931 
1932 static int f2fs_write_begin(struct file *file, struct address_space *mapping,
1933 		loff_t pos, unsigned len, unsigned flags,
1934 		struct page **pagep, void **fsdata)
1935 {
1936 	struct inode *inode = mapping->host;
1937 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1938 	struct page *page = NULL;
1939 	pgoff_t index = ((unsigned long long) pos) >> PAGE_SHIFT;
1940 	bool need_balance = false;
1941 	block_t blkaddr = NULL_ADDR;
1942 	int err = 0;
1943 
1944 	trace_f2fs_write_begin(inode, pos, len, flags);
1945 
1946 	if (f2fs_is_atomic_file(inode) &&
1947 			!available_free_memory(sbi, INMEM_PAGES)) {
1948 		err = -ENOMEM;
1949 		goto fail;
1950 	}
1951 
1952 	/*
1953 	 * We should check this at this moment to avoid deadlock on inode page
1954 	 * and #0 page. The locking rule for inline_data conversion should be:
1955 	 * lock_page(page #0) -> lock_page(inode_page)
1956 	 */
1957 	if (index != 0) {
1958 		err = f2fs_convert_inline_inode(inode);
1959 		if (err)
1960 			goto fail;
1961 	}
1962 repeat:
1963 	/*
1964 	 * Do not use grab_cache_page_write_begin() to avoid deadlock due to
1965 	 * wait_for_stable_page. Will wait that below with our IO control.
1966 	 */
1967 	page = f2fs_pagecache_get_page(mapping, index,
1968 				FGP_LOCK | FGP_WRITE | FGP_CREAT, GFP_NOFS);
1969 	if (!page) {
1970 		err = -ENOMEM;
1971 		goto fail;
1972 	}
1973 
1974 	*pagep = page;
1975 
1976 	err = prepare_write_begin(sbi, page, pos, len,
1977 					&blkaddr, &need_balance);
1978 	if (err)
1979 		goto fail;
1980 
1981 	if (need_balance && has_not_enough_free_secs(sbi, 0, 0)) {
1982 		unlock_page(page);
1983 		f2fs_balance_fs(sbi, true);
1984 		lock_page(page);
1985 		if (page->mapping != mapping) {
1986 			/* The page got truncated from under us */
1987 			f2fs_put_page(page, 1);
1988 			goto repeat;
1989 		}
1990 	}
1991 
1992 	f2fs_wait_on_page_writeback(page, DATA, false);
1993 
1994 	/* wait for GCed encrypted page writeback */
1995 	if (f2fs_encrypted_file(inode))
1996 		f2fs_wait_on_block_writeback(sbi, blkaddr);
1997 
1998 	if (len == PAGE_SIZE || PageUptodate(page))
1999 		return 0;
2000 
2001 	if (!(pos & (PAGE_SIZE - 1)) && (pos + len) >= i_size_read(inode)) {
2002 		zero_user_segment(page, len, PAGE_SIZE);
2003 		return 0;
2004 	}
2005 
2006 	if (blkaddr == NEW_ADDR) {
2007 		zero_user_segment(page, 0, PAGE_SIZE);
2008 		SetPageUptodate(page);
2009 	} else {
2010 		err = f2fs_submit_page_read(inode, page, blkaddr);
2011 		if (err)
2012 			goto fail;
2013 
2014 		lock_page(page);
2015 		if (unlikely(page->mapping != mapping)) {
2016 			f2fs_put_page(page, 1);
2017 			goto repeat;
2018 		}
2019 		if (unlikely(!PageUptodate(page))) {
2020 			err = -EIO;
2021 			goto fail;
2022 		}
2023 	}
2024 	return 0;
2025 
2026 fail:
2027 	f2fs_put_page(page, 1);
2028 	f2fs_write_failed(mapping, pos + len);
2029 	if (f2fs_is_atomic_file(inode))
2030 		drop_inmem_pages_all(sbi);
2031 	return err;
2032 }
2033 
2034 static int f2fs_write_end(struct file *file,
2035 			struct address_space *mapping,
2036 			loff_t pos, unsigned len, unsigned copied,
2037 			struct page *page, void *fsdata)
2038 {
2039 	struct inode *inode = page->mapping->host;
2040 
2041 	trace_f2fs_write_end(inode, pos, len, copied);
2042 
2043 	/*
2044 	 * This should be come from len == PAGE_SIZE, and we expect copied
2045 	 * should be PAGE_SIZE. Otherwise, we treat it with zero copied and
2046 	 * let generic_perform_write() try to copy data again through copied=0.
2047 	 */
2048 	if (!PageUptodate(page)) {
2049 		if (unlikely(copied != len))
2050 			copied = 0;
2051 		else
2052 			SetPageUptodate(page);
2053 	}
2054 	if (!copied)
2055 		goto unlock_out;
2056 
2057 	set_page_dirty(page);
2058 
2059 	if (pos + copied > i_size_read(inode))
2060 		f2fs_i_size_write(inode, pos + copied);
2061 unlock_out:
2062 	f2fs_put_page(page, 1);
2063 	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
2064 	return copied;
2065 }
2066 
2067 static int check_direct_IO(struct inode *inode, struct iov_iter *iter,
2068 			   loff_t offset)
2069 {
2070 	unsigned blocksize_mask = inode->i_sb->s_blocksize - 1;
2071 
2072 	if (offset & blocksize_mask)
2073 		return -EINVAL;
2074 
2075 	if (iov_iter_alignment(iter) & blocksize_mask)
2076 		return -EINVAL;
2077 
2078 	return 0;
2079 }
2080 
2081 static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
2082 {
2083 	struct address_space *mapping = iocb->ki_filp->f_mapping;
2084 	struct inode *inode = mapping->host;
2085 	size_t count = iov_iter_count(iter);
2086 	loff_t offset = iocb->ki_pos;
2087 	int rw = iov_iter_rw(iter);
2088 	int err;
2089 
2090 	err = check_direct_IO(inode, iter, offset);
2091 	if (err)
2092 		return err;
2093 
2094 	if (__force_buffered_io(inode, rw))
2095 		return 0;
2096 
2097 	trace_f2fs_direct_IO_enter(inode, offset, count, rw);
2098 
2099 	down_read(&F2FS_I(inode)->dio_rwsem[rw]);
2100 	err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio);
2101 	up_read(&F2FS_I(inode)->dio_rwsem[rw]);
2102 
2103 	if (rw == WRITE) {
2104 		if (err > 0) {
2105 			f2fs_update_iostat(F2FS_I_SB(inode), APP_DIRECT_IO,
2106 									err);
2107 			set_inode_flag(inode, FI_UPDATE_WRITE);
2108 		} else if (err < 0) {
2109 			f2fs_write_failed(mapping, offset + count);
2110 		}
2111 	}
2112 
2113 	trace_f2fs_direct_IO_exit(inode, offset, count, rw, err);
2114 
2115 	return err;
2116 }
2117 
2118 void f2fs_invalidate_page(struct page *page, unsigned int offset,
2119 							unsigned int length)
2120 {
2121 	struct inode *inode = page->mapping->host;
2122 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
2123 
2124 	if (inode->i_ino >= F2FS_ROOT_INO(sbi) &&
2125 		(offset % PAGE_SIZE || length != PAGE_SIZE))
2126 		return;
2127 
2128 	if (PageDirty(page)) {
2129 		if (inode->i_ino == F2FS_META_INO(sbi)) {
2130 			dec_page_count(sbi, F2FS_DIRTY_META);
2131 		} else if (inode->i_ino == F2FS_NODE_INO(sbi)) {
2132 			dec_page_count(sbi, F2FS_DIRTY_NODES);
2133 		} else {
2134 			inode_dec_dirty_pages(inode);
2135 			remove_dirty_inode(inode);
2136 		}
2137 	}
2138 
2139 	/* This is atomic written page, keep Private */
2140 	if (IS_ATOMIC_WRITTEN_PAGE(page))
2141 		return drop_inmem_page(inode, page);
2142 
2143 	set_page_private(page, 0);
2144 	ClearPagePrivate(page);
2145 }
2146 
2147 int f2fs_release_page(struct page *page, gfp_t wait)
2148 {
2149 	/* If this is dirty page, keep PagePrivate */
2150 	if (PageDirty(page))
2151 		return 0;
2152 
2153 	/* This is atomic written page, keep Private */
2154 	if (IS_ATOMIC_WRITTEN_PAGE(page))
2155 		return 0;
2156 
2157 	set_page_private(page, 0);
2158 	ClearPagePrivate(page);
2159 	return 1;
2160 }
2161 
2162 /*
2163  * This was copied from __set_page_dirty_buffers which gives higher performance
2164  * in very high speed storages. (e.g., pmem)
2165  */
2166 void f2fs_set_page_dirty_nobuffers(struct page *page)
2167 {
2168 	struct address_space *mapping = page->mapping;
2169 	unsigned long flags;
2170 
2171 	if (unlikely(!mapping))
2172 		return;
2173 
2174 	spin_lock(&mapping->private_lock);
2175 	lock_page_memcg(page);
2176 	SetPageDirty(page);
2177 	spin_unlock(&mapping->private_lock);
2178 
2179 	spin_lock_irqsave(&mapping->tree_lock, flags);
2180 	WARN_ON_ONCE(!PageUptodate(page));
2181 	account_page_dirtied(page, mapping);
2182 	radix_tree_tag_set(&mapping->page_tree,
2183 			page_index(page), PAGECACHE_TAG_DIRTY);
2184 	spin_unlock_irqrestore(&mapping->tree_lock, flags);
2185 	unlock_page_memcg(page);
2186 
2187 	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
2188 	return;
2189 }
2190 
2191 static int f2fs_set_data_page_dirty(struct page *page)
2192 {
2193 	struct address_space *mapping = page->mapping;
2194 	struct inode *inode = mapping->host;
2195 
2196 	trace_f2fs_set_page_dirty(page, DATA);
2197 
2198 	if (!PageUptodate(page))
2199 		SetPageUptodate(page);
2200 
2201 	if (f2fs_is_atomic_file(inode) && !f2fs_is_commit_atomic_write(inode)) {
2202 		if (!IS_ATOMIC_WRITTEN_PAGE(page)) {
2203 			register_inmem_page(inode, page);
2204 			return 1;
2205 		}
2206 		/*
2207 		 * Previously, this page has been registered, we just
2208 		 * return here.
2209 		 */
2210 		return 0;
2211 	}
2212 
2213 	if (!PageDirty(page)) {
2214 		f2fs_set_page_dirty_nobuffers(page);
2215 		update_dirty_page(inode, page);
2216 		return 1;
2217 	}
2218 	return 0;
2219 }
2220 
2221 static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
2222 {
2223 	struct inode *inode = mapping->host;
2224 
2225 	if (f2fs_has_inline_data(inode))
2226 		return 0;
2227 
2228 	/* make sure allocating whole blocks */
2229 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
2230 		filemap_write_and_wait(mapping);
2231 
2232 	return generic_block_bmap(mapping, block, get_data_block_bmap);
2233 }
2234 
2235 #ifdef CONFIG_MIGRATION
2236 #include <linux/migrate.h>
2237 
2238 int f2fs_migrate_page(struct address_space *mapping,
2239 		struct page *newpage, struct page *page, enum migrate_mode mode)
2240 {
2241 	int rc, extra_count;
2242 	struct f2fs_inode_info *fi = F2FS_I(mapping->host);
2243 	bool atomic_written = IS_ATOMIC_WRITTEN_PAGE(page);
2244 
2245 	BUG_ON(PageWriteback(page));
2246 
2247 	/* migrating an atomic written page is safe with the inmem_lock hold */
2248 	if (atomic_written) {
2249 		if (mode != MIGRATE_SYNC)
2250 			return -EBUSY;
2251 		if (!mutex_trylock(&fi->inmem_lock))
2252 			return -EAGAIN;
2253 	}
2254 
2255 	/*
2256 	 * A reference is expected if PagePrivate set when move mapping,
2257 	 * however F2FS breaks this for maintaining dirty page counts when
2258 	 * truncating pages. So here adjusting the 'extra_count' make it work.
2259 	 */
2260 	extra_count = (atomic_written ? 1 : 0) - page_has_private(page);
2261 	rc = migrate_page_move_mapping(mapping, newpage,
2262 				page, NULL, mode, extra_count);
2263 	if (rc != MIGRATEPAGE_SUCCESS) {
2264 		if (atomic_written)
2265 			mutex_unlock(&fi->inmem_lock);
2266 		return rc;
2267 	}
2268 
2269 	if (atomic_written) {
2270 		struct inmem_pages *cur;
2271 		list_for_each_entry(cur, &fi->inmem_pages, list)
2272 			if (cur->page == page) {
2273 				cur->page = newpage;
2274 				break;
2275 			}
2276 		mutex_unlock(&fi->inmem_lock);
2277 		put_page(page);
2278 		get_page(newpage);
2279 	}
2280 
2281 	if (PagePrivate(page))
2282 		SetPagePrivate(newpage);
2283 	set_page_private(newpage, page_private(page));
2284 
2285 	if (mode != MIGRATE_SYNC_NO_COPY)
2286 		migrate_page_copy(newpage, page);
2287 	else
2288 		migrate_page_states(newpage, page);
2289 
2290 	return MIGRATEPAGE_SUCCESS;
2291 }
2292 #endif
2293 
2294 const struct address_space_operations f2fs_dblock_aops = {
2295 	.readpage	= f2fs_read_data_page,
2296 	.readpages	= f2fs_read_data_pages,
2297 	.writepage	= f2fs_write_data_page,
2298 	.writepages	= f2fs_write_data_pages,
2299 	.write_begin	= f2fs_write_begin,
2300 	.write_end	= f2fs_write_end,
2301 	.set_page_dirty	= f2fs_set_data_page_dirty,
2302 	.invalidatepage	= f2fs_invalidate_page,
2303 	.releasepage	= f2fs_release_page,
2304 	.direct_IO	= f2fs_direct_IO,
2305 	.bmap		= f2fs_bmap,
2306 #ifdef CONFIG_MIGRATION
2307 	.migratepage    = f2fs_migrate_page,
2308 #endif
2309 };
2310