xref: /openbmc/linux/fs/f2fs/data.c (revision 77a87824)
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 
26 #include "f2fs.h"
27 #include "node.h"
28 #include "segment.h"
29 #include "trace.h"
30 #include <trace/events/f2fs.h>
31 
32 static void f2fs_read_end_io(struct bio *bio)
33 {
34 	struct bio_vec *bvec;
35 	int i;
36 
37 	if (f2fs_bio_encrypted(bio)) {
38 		if (bio->bi_error) {
39 			fscrypt_release_ctx(bio->bi_private);
40 		} else {
41 			fscrypt_decrypt_bio_pages(bio->bi_private, bio);
42 			return;
43 		}
44 	}
45 
46 	bio_for_each_segment_all(bvec, bio, i) {
47 		struct page *page = bvec->bv_page;
48 
49 		if (!bio->bi_error) {
50 			if (!PageUptodate(page))
51 				SetPageUptodate(page);
52 		} else {
53 			ClearPageUptodate(page);
54 			SetPageError(page);
55 		}
56 		unlock_page(page);
57 	}
58 	bio_put(bio);
59 }
60 
61 static void f2fs_write_end_io(struct bio *bio)
62 {
63 	struct f2fs_sb_info *sbi = bio->bi_private;
64 	struct bio_vec *bvec;
65 	int i;
66 
67 	bio_for_each_segment_all(bvec, bio, i) {
68 		struct page *page = bvec->bv_page;
69 
70 		fscrypt_pullback_bio_page(&page, true);
71 
72 		if (unlikely(bio->bi_error)) {
73 			set_bit(AS_EIO, &page->mapping->flags);
74 			f2fs_stop_checkpoint(sbi, true);
75 		}
76 		end_page_writeback(page);
77 	}
78 	if (atomic_dec_and_test(&sbi->nr_wb_bios) &&
79 				wq_has_sleeper(&sbi->cp_wait))
80 		wake_up(&sbi->cp_wait);
81 
82 	bio_put(bio);
83 }
84 
85 /*
86  * Low-level block read/write IO operations.
87  */
88 static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
89 				int npages, bool is_read)
90 {
91 	struct bio *bio;
92 
93 	bio = f2fs_bio_alloc(npages);
94 
95 	bio->bi_bdev = sbi->sb->s_bdev;
96 	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blk_addr);
97 	bio->bi_end_io = is_read ? f2fs_read_end_io : f2fs_write_end_io;
98 	bio->bi_private = is_read ? NULL : sbi;
99 
100 	return bio;
101 }
102 
103 static inline void __submit_bio(struct f2fs_sb_info *sbi,
104 				struct bio *bio, enum page_type type)
105 {
106 	if (!is_read_io(bio_op(bio))) {
107 		atomic_inc(&sbi->nr_wb_bios);
108 		if (f2fs_sb_mounted_hmsmr(sbi->sb) &&
109 			current->plug && (type == DATA || type == NODE))
110 			blk_finish_plug(current->plug);
111 	}
112 	submit_bio(bio);
113 }
114 
115 static void __submit_merged_bio(struct f2fs_bio_info *io)
116 {
117 	struct f2fs_io_info *fio = &io->fio;
118 
119 	if (!io->bio)
120 		return;
121 
122 	if (is_read_io(fio->op))
123 		trace_f2fs_submit_read_bio(io->sbi->sb, fio, io->bio);
124 	else
125 		trace_f2fs_submit_write_bio(io->sbi->sb, fio, io->bio);
126 
127 	bio_set_op_attrs(io->bio, fio->op, fio->op_flags);
128 
129 	__submit_bio(io->sbi, io->bio, fio->type);
130 	io->bio = NULL;
131 }
132 
133 static bool __has_merged_page(struct f2fs_bio_info *io, struct inode *inode,
134 						struct page *page, nid_t ino)
135 {
136 	struct bio_vec *bvec;
137 	struct page *target;
138 	int i;
139 
140 	if (!io->bio)
141 		return false;
142 
143 	if (!inode && !page && !ino)
144 		return true;
145 
146 	bio_for_each_segment_all(bvec, io->bio, i) {
147 
148 		if (bvec->bv_page->mapping)
149 			target = bvec->bv_page;
150 		else
151 			target = fscrypt_control_page(bvec->bv_page);
152 
153 		if (inode && inode == target->mapping->host)
154 			return true;
155 		if (page && page == target)
156 			return true;
157 		if (ino && ino == ino_of_node(target))
158 			return true;
159 	}
160 
161 	return false;
162 }
163 
164 static bool has_merged_page(struct f2fs_sb_info *sbi, struct inode *inode,
165 						struct page *page, nid_t ino,
166 						enum page_type type)
167 {
168 	enum page_type btype = PAGE_TYPE_OF_BIO(type);
169 	struct f2fs_bio_info *io = &sbi->write_io[btype];
170 	bool ret;
171 
172 	down_read(&io->io_rwsem);
173 	ret = __has_merged_page(io, inode, page, ino);
174 	up_read(&io->io_rwsem);
175 	return ret;
176 }
177 
178 static void __f2fs_submit_merged_bio(struct f2fs_sb_info *sbi,
179 				struct inode *inode, struct page *page,
180 				nid_t ino, enum page_type type, int rw)
181 {
182 	enum page_type btype = PAGE_TYPE_OF_BIO(type);
183 	struct f2fs_bio_info *io;
184 
185 	io = is_read_io(rw) ? &sbi->read_io : &sbi->write_io[btype];
186 
187 	down_write(&io->io_rwsem);
188 
189 	if (!__has_merged_page(io, inode, page, ino))
190 		goto out;
191 
192 	/* change META to META_FLUSH in the checkpoint procedure */
193 	if (type >= META_FLUSH) {
194 		io->fio.type = META_FLUSH;
195 		io->fio.op = REQ_OP_WRITE;
196 		if (test_opt(sbi, NOBARRIER))
197 			io->fio.op_flags = WRITE_FLUSH | REQ_META | REQ_PRIO;
198 		else
199 			io->fio.op_flags = WRITE_FLUSH_FUA | REQ_META |
200 								REQ_PRIO;
201 	}
202 	__submit_merged_bio(io);
203 out:
204 	up_write(&io->io_rwsem);
205 }
206 
207 void f2fs_submit_merged_bio(struct f2fs_sb_info *sbi, enum page_type type,
208 									int rw)
209 {
210 	__f2fs_submit_merged_bio(sbi, NULL, NULL, 0, type, rw);
211 }
212 
213 void f2fs_submit_merged_bio_cond(struct f2fs_sb_info *sbi,
214 				struct inode *inode, struct page *page,
215 				nid_t ino, enum page_type type, int rw)
216 {
217 	if (has_merged_page(sbi, inode, page, ino, type))
218 		__f2fs_submit_merged_bio(sbi, inode, page, ino, type, rw);
219 }
220 
221 void f2fs_flush_merged_bios(struct f2fs_sb_info *sbi)
222 {
223 	f2fs_submit_merged_bio(sbi, DATA, WRITE);
224 	f2fs_submit_merged_bio(sbi, NODE, WRITE);
225 	f2fs_submit_merged_bio(sbi, META, WRITE);
226 }
227 
228 /*
229  * Fill the locked page with data located in the block address.
230  * Return unlocked page.
231  */
232 int f2fs_submit_page_bio(struct f2fs_io_info *fio)
233 {
234 	struct bio *bio;
235 	struct page *page = fio->encrypted_page ?
236 			fio->encrypted_page : fio->page;
237 
238 	trace_f2fs_submit_page_bio(page, fio);
239 	f2fs_trace_ios(fio, 0);
240 
241 	/* Allocate a new bio */
242 	bio = __bio_alloc(fio->sbi, fio->new_blkaddr, 1, is_read_io(fio->op));
243 
244 	if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
245 		bio_put(bio);
246 		return -EFAULT;
247 	}
248 	bio->bi_rw = fio->op_flags;
249 	bio_set_op_attrs(bio, fio->op, fio->op_flags);
250 
251 	__submit_bio(fio->sbi, bio, fio->type);
252 	return 0;
253 }
254 
255 void f2fs_submit_page_mbio(struct f2fs_io_info *fio)
256 {
257 	struct f2fs_sb_info *sbi = fio->sbi;
258 	enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);
259 	struct f2fs_bio_info *io;
260 	bool is_read = is_read_io(fio->op);
261 	struct page *bio_page;
262 
263 	io = is_read ? &sbi->read_io : &sbi->write_io[btype];
264 
265 	if (fio->old_blkaddr != NEW_ADDR)
266 		verify_block_addr(sbi, fio->old_blkaddr);
267 	verify_block_addr(sbi, fio->new_blkaddr);
268 
269 	down_write(&io->io_rwsem);
270 
271 	if (io->bio && (io->last_block_in_bio != fio->new_blkaddr - 1 ||
272 	    (io->fio.op != fio->op || io->fio.op_flags != fio->op_flags)))
273 		__submit_merged_bio(io);
274 alloc_new:
275 	if (io->bio == NULL) {
276 		int bio_blocks = MAX_BIO_BLOCKS(sbi);
277 
278 		io->bio = __bio_alloc(sbi, fio->new_blkaddr,
279 						bio_blocks, is_read);
280 		io->fio = *fio;
281 	}
282 
283 	bio_page = fio->encrypted_page ? fio->encrypted_page : fio->page;
284 
285 	if (bio_add_page(io->bio, bio_page, PAGE_SIZE, 0) <
286 							PAGE_SIZE) {
287 		__submit_merged_bio(io);
288 		goto alloc_new;
289 	}
290 
291 	io->last_block_in_bio = fio->new_blkaddr;
292 	f2fs_trace_ios(fio, 0);
293 
294 	up_write(&io->io_rwsem);
295 	trace_f2fs_submit_page_mbio(fio->page, fio);
296 }
297 
298 static void __set_data_blkaddr(struct dnode_of_data *dn)
299 {
300 	struct f2fs_node *rn = F2FS_NODE(dn->node_page);
301 	__le32 *addr_array;
302 
303 	/* Get physical address of data block */
304 	addr_array = blkaddr_in_node(rn);
305 	addr_array[dn->ofs_in_node] = cpu_to_le32(dn->data_blkaddr);
306 }
307 
308 /*
309  * Lock ordering for the change of data block address:
310  * ->data_page
311  *  ->node_page
312  *    update block addresses in the node page
313  */
314 void set_data_blkaddr(struct dnode_of_data *dn)
315 {
316 	f2fs_wait_on_page_writeback(dn->node_page, NODE, true);
317 	__set_data_blkaddr(dn);
318 	if (set_page_dirty(dn->node_page))
319 		dn->node_changed = true;
320 }
321 
322 void f2fs_update_data_blkaddr(struct dnode_of_data *dn, block_t blkaddr)
323 {
324 	dn->data_blkaddr = blkaddr;
325 	set_data_blkaddr(dn);
326 	f2fs_update_extent_cache(dn);
327 }
328 
329 /* dn->ofs_in_node will be returned with up-to-date last block pointer */
330 int reserve_new_blocks(struct dnode_of_data *dn, blkcnt_t count)
331 {
332 	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
333 
334 	if (!count)
335 		return 0;
336 
337 	if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC)))
338 		return -EPERM;
339 	if (unlikely(!inc_valid_block_count(sbi, dn->inode, &count)))
340 		return -ENOSPC;
341 
342 	trace_f2fs_reserve_new_blocks(dn->inode, dn->nid,
343 						dn->ofs_in_node, count);
344 
345 	f2fs_wait_on_page_writeback(dn->node_page, NODE, true);
346 
347 	for (; count > 0; dn->ofs_in_node++) {
348 		block_t blkaddr =
349 			datablock_addr(dn->node_page, dn->ofs_in_node);
350 		if (blkaddr == NULL_ADDR) {
351 			dn->data_blkaddr = NEW_ADDR;
352 			__set_data_blkaddr(dn);
353 			count--;
354 		}
355 	}
356 
357 	if (set_page_dirty(dn->node_page))
358 		dn->node_changed = true;
359 	return 0;
360 }
361 
362 /* Should keep dn->ofs_in_node unchanged */
363 int reserve_new_block(struct dnode_of_data *dn)
364 {
365 	unsigned int ofs_in_node = dn->ofs_in_node;
366 	int ret;
367 
368 	ret = reserve_new_blocks(dn, 1);
369 	dn->ofs_in_node = ofs_in_node;
370 	return ret;
371 }
372 
373 int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index)
374 {
375 	bool need_put = dn->inode_page ? false : true;
376 	int err;
377 
378 	err = get_dnode_of_data(dn, index, ALLOC_NODE);
379 	if (err)
380 		return err;
381 
382 	if (dn->data_blkaddr == NULL_ADDR)
383 		err = reserve_new_block(dn);
384 	if (err || need_put)
385 		f2fs_put_dnode(dn);
386 	return err;
387 }
388 
389 int f2fs_get_block(struct dnode_of_data *dn, pgoff_t index)
390 {
391 	struct extent_info ei;
392 	struct inode *inode = dn->inode;
393 
394 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
395 		dn->data_blkaddr = ei.blk + index - ei.fofs;
396 		return 0;
397 	}
398 
399 	return f2fs_reserve_block(dn, index);
400 }
401 
402 struct page *get_read_data_page(struct inode *inode, pgoff_t index,
403 						int op_flags, bool for_write)
404 {
405 	struct address_space *mapping = inode->i_mapping;
406 	struct dnode_of_data dn;
407 	struct page *page;
408 	struct extent_info ei;
409 	int err;
410 	struct f2fs_io_info fio = {
411 		.sbi = F2FS_I_SB(inode),
412 		.type = DATA,
413 		.op = REQ_OP_READ,
414 		.op_flags = op_flags,
415 		.encrypted_page = NULL,
416 	};
417 
418 	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
419 		return read_mapping_page(mapping, index, NULL);
420 
421 	page = f2fs_grab_cache_page(mapping, index, for_write);
422 	if (!page)
423 		return ERR_PTR(-ENOMEM);
424 
425 	if (f2fs_lookup_extent_cache(inode, index, &ei)) {
426 		dn.data_blkaddr = ei.blk + index - ei.fofs;
427 		goto got_it;
428 	}
429 
430 	set_new_dnode(&dn, inode, NULL, NULL, 0);
431 	err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
432 	if (err)
433 		goto put_err;
434 	f2fs_put_dnode(&dn);
435 
436 	if (unlikely(dn.data_blkaddr == NULL_ADDR)) {
437 		err = -ENOENT;
438 		goto put_err;
439 	}
440 got_it:
441 	if (PageUptodate(page)) {
442 		unlock_page(page);
443 		return page;
444 	}
445 
446 	/*
447 	 * A new dentry page is allocated but not able to be written, since its
448 	 * new inode page couldn't be allocated due to -ENOSPC.
449 	 * In such the case, its blkaddr can be remained as NEW_ADDR.
450 	 * see, f2fs_add_link -> get_new_data_page -> init_inode_metadata.
451 	 */
452 	if (dn.data_blkaddr == NEW_ADDR) {
453 		zero_user_segment(page, 0, PAGE_SIZE);
454 		if (!PageUptodate(page))
455 			SetPageUptodate(page);
456 		unlock_page(page);
457 		return page;
458 	}
459 
460 	fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
461 	fio.page = page;
462 	err = f2fs_submit_page_bio(&fio);
463 	if (err)
464 		goto put_err;
465 	return page;
466 
467 put_err:
468 	f2fs_put_page(page, 1);
469 	return ERR_PTR(err);
470 }
471 
472 struct page *find_data_page(struct inode *inode, pgoff_t index)
473 {
474 	struct address_space *mapping = inode->i_mapping;
475 	struct page *page;
476 
477 	page = find_get_page(mapping, index);
478 	if (page && PageUptodate(page))
479 		return page;
480 	f2fs_put_page(page, 0);
481 
482 	page = get_read_data_page(inode, index, READ_SYNC, false);
483 	if (IS_ERR(page))
484 		return page;
485 
486 	if (PageUptodate(page))
487 		return page;
488 
489 	wait_on_page_locked(page);
490 	if (unlikely(!PageUptodate(page))) {
491 		f2fs_put_page(page, 0);
492 		return ERR_PTR(-EIO);
493 	}
494 	return page;
495 }
496 
497 /*
498  * If it tries to access a hole, return an error.
499  * Because, the callers, functions in dir.c and GC, should be able to know
500  * whether this page exists or not.
501  */
502 struct page *get_lock_data_page(struct inode *inode, pgoff_t index,
503 							bool for_write)
504 {
505 	struct address_space *mapping = inode->i_mapping;
506 	struct page *page;
507 repeat:
508 	page = get_read_data_page(inode, index, READ_SYNC, for_write);
509 	if (IS_ERR(page))
510 		return page;
511 
512 	/* wait for read completion */
513 	lock_page(page);
514 	if (unlikely(page->mapping != mapping)) {
515 		f2fs_put_page(page, 1);
516 		goto repeat;
517 	}
518 	if (unlikely(!PageUptodate(page))) {
519 		f2fs_put_page(page, 1);
520 		return ERR_PTR(-EIO);
521 	}
522 	return page;
523 }
524 
525 /*
526  * Caller ensures that this data page is never allocated.
527  * A new zero-filled data page is allocated in the page cache.
528  *
529  * Also, caller should grab and release a rwsem by calling f2fs_lock_op() and
530  * f2fs_unlock_op().
531  * Note that, ipage is set only by make_empty_dir, and if any error occur,
532  * ipage should be released by this function.
533  */
534 struct page *get_new_data_page(struct inode *inode,
535 		struct page *ipage, pgoff_t index, bool new_i_size)
536 {
537 	struct address_space *mapping = inode->i_mapping;
538 	struct page *page;
539 	struct dnode_of_data dn;
540 	int err;
541 
542 	page = f2fs_grab_cache_page(mapping, index, true);
543 	if (!page) {
544 		/*
545 		 * before exiting, we should make sure ipage will be released
546 		 * if any error occur.
547 		 */
548 		f2fs_put_page(ipage, 1);
549 		return ERR_PTR(-ENOMEM);
550 	}
551 
552 	set_new_dnode(&dn, inode, ipage, NULL, 0);
553 	err = f2fs_reserve_block(&dn, index);
554 	if (err) {
555 		f2fs_put_page(page, 1);
556 		return ERR_PTR(err);
557 	}
558 	if (!ipage)
559 		f2fs_put_dnode(&dn);
560 
561 	if (PageUptodate(page))
562 		goto got_it;
563 
564 	if (dn.data_blkaddr == NEW_ADDR) {
565 		zero_user_segment(page, 0, PAGE_SIZE);
566 		if (!PageUptodate(page))
567 			SetPageUptodate(page);
568 	} else {
569 		f2fs_put_page(page, 1);
570 
571 		/* if ipage exists, blkaddr should be NEW_ADDR */
572 		f2fs_bug_on(F2FS_I_SB(inode), ipage);
573 		page = get_lock_data_page(inode, index, true);
574 		if (IS_ERR(page))
575 			return page;
576 	}
577 got_it:
578 	if (new_i_size && i_size_read(inode) <
579 				((loff_t)(index + 1) << PAGE_SHIFT))
580 		f2fs_i_size_write(inode, ((loff_t)(index + 1) << PAGE_SHIFT));
581 	return page;
582 }
583 
584 static int __allocate_data_block(struct dnode_of_data *dn)
585 {
586 	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
587 	struct f2fs_summary sum;
588 	struct node_info ni;
589 	int seg = CURSEG_WARM_DATA;
590 	pgoff_t fofs;
591 	blkcnt_t count = 1;
592 
593 	if (unlikely(is_inode_flag_set(dn->inode, FI_NO_ALLOC)))
594 		return -EPERM;
595 
596 	dn->data_blkaddr = datablock_addr(dn->node_page, dn->ofs_in_node);
597 	if (dn->data_blkaddr == NEW_ADDR)
598 		goto alloc;
599 
600 	if (unlikely(!inc_valid_block_count(sbi, dn->inode, &count)))
601 		return -ENOSPC;
602 
603 alloc:
604 	get_node_info(sbi, dn->nid, &ni);
605 	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
606 
607 	if (dn->ofs_in_node == 0 && dn->inode_page == dn->node_page)
608 		seg = CURSEG_DIRECT_IO;
609 
610 	allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr,
611 								&sum, seg);
612 	set_data_blkaddr(dn);
613 
614 	/* update i_size */
615 	fofs = start_bidx_of_node(ofs_of_node(dn->node_page), dn->inode) +
616 							dn->ofs_in_node;
617 	if (i_size_read(dn->inode) < ((loff_t)(fofs + 1) << PAGE_SHIFT))
618 		f2fs_i_size_write(dn->inode,
619 				((loff_t)(fofs + 1) << PAGE_SHIFT));
620 	return 0;
621 }
622 
623 ssize_t f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from)
624 {
625 	struct inode *inode = file_inode(iocb->ki_filp);
626 	struct f2fs_map_blocks map;
627 	ssize_t ret = 0;
628 
629 	map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos);
630 	map.m_len = F2FS_BYTES_TO_BLK(iov_iter_count(from));
631 	map.m_next_pgofs = NULL;
632 
633 	if (f2fs_encrypted_inode(inode))
634 		return 0;
635 
636 	if (iocb->ki_flags & IOCB_DIRECT) {
637 		ret = f2fs_convert_inline_inode(inode);
638 		if (ret)
639 			return ret;
640 		return f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_DIO);
641 	}
642 	if (iocb->ki_pos + iov_iter_count(from) > MAX_INLINE_DATA) {
643 		ret = f2fs_convert_inline_inode(inode);
644 		if (ret)
645 			return ret;
646 	}
647 	if (!f2fs_has_inline_data(inode))
648 		return f2fs_map_blocks(inode, &map, 1, F2FS_GET_BLOCK_PRE_AIO);
649 	return ret;
650 }
651 
652 /*
653  * f2fs_map_blocks() now supported readahead/bmap/rw direct_IO with
654  * f2fs_map_blocks structure.
655  * If original data blocks are allocated, then give them to blockdev.
656  * Otherwise,
657  *     a. preallocate requested block addresses
658  *     b. do not use extent cache for better performance
659  *     c. give the block addresses to blockdev
660  */
661 int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
662 						int create, int flag)
663 {
664 	unsigned int maxblocks = map->m_len;
665 	struct dnode_of_data dn;
666 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
667 	int mode = create ? ALLOC_NODE : LOOKUP_NODE;
668 	pgoff_t pgofs, end_offset, end;
669 	int err = 0, ofs = 1;
670 	unsigned int ofs_in_node, last_ofs_in_node;
671 	blkcnt_t prealloc;
672 	struct extent_info ei;
673 	bool allocated = false;
674 	block_t blkaddr;
675 
676 	map->m_len = 0;
677 	map->m_flags = 0;
678 
679 	/* it only supports block size == page size */
680 	pgofs =	(pgoff_t)map->m_lblk;
681 	end = pgofs + maxblocks;
682 
683 	if (!create && f2fs_lookup_extent_cache(inode, pgofs, &ei)) {
684 		map->m_pblk = ei.blk + pgofs - ei.fofs;
685 		map->m_len = min((pgoff_t)maxblocks, ei.fofs + ei.len - pgofs);
686 		map->m_flags = F2FS_MAP_MAPPED;
687 		goto out;
688 	}
689 
690 next_dnode:
691 	if (create)
692 		f2fs_lock_op(sbi);
693 
694 	/* When reading holes, we need its node page */
695 	set_new_dnode(&dn, inode, NULL, NULL, 0);
696 	err = get_dnode_of_data(&dn, pgofs, mode);
697 	if (err) {
698 		if (flag == F2FS_GET_BLOCK_BMAP)
699 			map->m_pblk = 0;
700 		if (err == -ENOENT) {
701 			err = 0;
702 			if (map->m_next_pgofs)
703 				*map->m_next_pgofs =
704 					get_next_page_offset(&dn, pgofs);
705 		}
706 		goto unlock_out;
707 	}
708 
709 	prealloc = 0;
710 	ofs_in_node = dn.ofs_in_node;
711 	end_offset = ADDRS_PER_PAGE(dn.node_page, inode);
712 
713 next_block:
714 	blkaddr = datablock_addr(dn.node_page, dn.ofs_in_node);
715 
716 	if (blkaddr == NEW_ADDR || blkaddr == NULL_ADDR) {
717 		if (create) {
718 			if (unlikely(f2fs_cp_error(sbi))) {
719 				err = -EIO;
720 				goto sync_out;
721 			}
722 			if (flag == F2FS_GET_BLOCK_PRE_AIO) {
723 				if (blkaddr == NULL_ADDR) {
724 					prealloc++;
725 					last_ofs_in_node = dn.ofs_in_node;
726 				}
727 			} else {
728 				err = __allocate_data_block(&dn);
729 				if (!err) {
730 					set_inode_flag(inode, FI_APPEND_WRITE);
731 					allocated = true;
732 				}
733 			}
734 			if (err)
735 				goto sync_out;
736 			map->m_flags = F2FS_MAP_NEW;
737 			blkaddr = dn.data_blkaddr;
738 		} else {
739 			if (flag == F2FS_GET_BLOCK_BMAP) {
740 				map->m_pblk = 0;
741 				goto sync_out;
742 			}
743 			if (flag == F2FS_GET_BLOCK_FIEMAP &&
744 						blkaddr == NULL_ADDR) {
745 				if (map->m_next_pgofs)
746 					*map->m_next_pgofs = pgofs + 1;
747 			}
748 			if (flag != F2FS_GET_BLOCK_FIEMAP ||
749 						blkaddr != NEW_ADDR)
750 				goto sync_out;
751 		}
752 	}
753 
754 	if (flag == F2FS_GET_BLOCK_PRE_AIO)
755 		goto skip;
756 
757 	if (map->m_len == 0) {
758 		/* preallocated unwritten block should be mapped for fiemap. */
759 		if (blkaddr == NEW_ADDR)
760 			map->m_flags |= F2FS_MAP_UNWRITTEN;
761 		map->m_flags |= F2FS_MAP_MAPPED;
762 
763 		map->m_pblk = blkaddr;
764 		map->m_len = 1;
765 	} else if ((map->m_pblk != NEW_ADDR &&
766 			blkaddr == (map->m_pblk + ofs)) ||
767 			(map->m_pblk == NEW_ADDR && blkaddr == NEW_ADDR) ||
768 			flag == F2FS_GET_BLOCK_PRE_DIO) {
769 		ofs++;
770 		map->m_len++;
771 	} else {
772 		goto sync_out;
773 	}
774 
775 skip:
776 	dn.ofs_in_node++;
777 	pgofs++;
778 
779 	/* preallocate blocks in batch for one dnode page */
780 	if (flag == F2FS_GET_BLOCK_PRE_AIO &&
781 			(pgofs == end || dn.ofs_in_node == end_offset)) {
782 
783 		dn.ofs_in_node = ofs_in_node;
784 		err = reserve_new_blocks(&dn, prealloc);
785 		if (err)
786 			goto sync_out;
787 
788 		map->m_len += dn.ofs_in_node - ofs_in_node;
789 		if (prealloc && dn.ofs_in_node != last_ofs_in_node + 1) {
790 			err = -ENOSPC;
791 			goto sync_out;
792 		}
793 		dn.ofs_in_node = end_offset;
794 	}
795 
796 	if (pgofs >= end)
797 		goto sync_out;
798 	else if (dn.ofs_in_node < end_offset)
799 		goto next_block;
800 
801 	f2fs_put_dnode(&dn);
802 
803 	if (create) {
804 		f2fs_unlock_op(sbi);
805 		f2fs_balance_fs(sbi, allocated);
806 	}
807 	allocated = false;
808 	goto next_dnode;
809 
810 sync_out:
811 	f2fs_put_dnode(&dn);
812 unlock_out:
813 	if (create) {
814 		f2fs_unlock_op(sbi);
815 		f2fs_balance_fs(sbi, allocated);
816 	}
817 out:
818 	trace_f2fs_map_blocks(inode, map, err);
819 	return err;
820 }
821 
822 static int __get_data_block(struct inode *inode, sector_t iblock,
823 			struct buffer_head *bh, int create, int flag,
824 			pgoff_t *next_pgofs)
825 {
826 	struct f2fs_map_blocks map;
827 	int ret;
828 
829 	map.m_lblk = iblock;
830 	map.m_len = bh->b_size >> inode->i_blkbits;
831 	map.m_next_pgofs = next_pgofs;
832 
833 	ret = f2fs_map_blocks(inode, &map, create, flag);
834 	if (!ret) {
835 		map_bh(bh, inode->i_sb, map.m_pblk);
836 		bh->b_state = (bh->b_state & ~F2FS_MAP_FLAGS) | map.m_flags;
837 		bh->b_size = map.m_len << inode->i_blkbits;
838 	}
839 	return ret;
840 }
841 
842 static int get_data_block(struct inode *inode, sector_t iblock,
843 			struct buffer_head *bh_result, int create, int flag,
844 			pgoff_t *next_pgofs)
845 {
846 	return __get_data_block(inode, iblock, bh_result, create,
847 							flag, next_pgofs);
848 }
849 
850 static int get_data_block_dio(struct inode *inode, sector_t iblock,
851 			struct buffer_head *bh_result, int create)
852 {
853 	return __get_data_block(inode, iblock, bh_result, create,
854 						F2FS_GET_BLOCK_DIO, NULL);
855 }
856 
857 static int get_data_block_bmap(struct inode *inode, sector_t iblock,
858 			struct buffer_head *bh_result, int create)
859 {
860 	/* Block number less than F2FS MAX BLOCKS */
861 	if (unlikely(iblock >= F2FS_I_SB(inode)->max_file_blocks))
862 		return -EFBIG;
863 
864 	return __get_data_block(inode, iblock, bh_result, create,
865 						F2FS_GET_BLOCK_BMAP, NULL);
866 }
867 
868 static inline sector_t logical_to_blk(struct inode *inode, loff_t offset)
869 {
870 	return (offset >> inode->i_blkbits);
871 }
872 
873 static inline loff_t blk_to_logical(struct inode *inode, sector_t blk)
874 {
875 	return (blk << inode->i_blkbits);
876 }
877 
878 int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
879 		u64 start, u64 len)
880 {
881 	struct buffer_head map_bh;
882 	sector_t start_blk, last_blk;
883 	pgoff_t next_pgofs;
884 	loff_t isize;
885 	u64 logical = 0, phys = 0, size = 0;
886 	u32 flags = 0;
887 	int ret = 0;
888 
889 	ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
890 	if (ret)
891 		return ret;
892 
893 	if (f2fs_has_inline_data(inode)) {
894 		ret = f2fs_inline_data_fiemap(inode, fieinfo, start, len);
895 		if (ret != -EAGAIN)
896 			return ret;
897 	}
898 
899 	inode_lock(inode);
900 
901 	isize = i_size_read(inode);
902 	if (start >= isize)
903 		goto out;
904 
905 	if (start + len > isize)
906 		len = isize - start;
907 
908 	if (logical_to_blk(inode, len) == 0)
909 		len = blk_to_logical(inode, 1);
910 
911 	start_blk = logical_to_blk(inode, start);
912 	last_blk = logical_to_blk(inode, start + len - 1);
913 
914 next:
915 	memset(&map_bh, 0, sizeof(struct buffer_head));
916 	map_bh.b_size = len;
917 
918 	ret = get_data_block(inode, start_blk, &map_bh, 0,
919 					F2FS_GET_BLOCK_FIEMAP, &next_pgofs);
920 	if (ret)
921 		goto out;
922 
923 	/* HOLE */
924 	if (!buffer_mapped(&map_bh)) {
925 		start_blk = next_pgofs;
926 		/* Go through holes util pass the EOF */
927 		if (blk_to_logical(inode, start_blk) < isize)
928 			goto prep_next;
929 		/* Found a hole beyond isize means no more extents.
930 		 * Note that the premise is that filesystems don't
931 		 * punch holes beyond isize and keep size unchanged.
932 		 */
933 		flags |= FIEMAP_EXTENT_LAST;
934 	}
935 
936 	if (size) {
937 		if (f2fs_encrypted_inode(inode))
938 			flags |= FIEMAP_EXTENT_DATA_ENCRYPTED;
939 
940 		ret = fiemap_fill_next_extent(fieinfo, logical,
941 				phys, size, flags);
942 	}
943 
944 	if (start_blk > last_blk || ret)
945 		goto out;
946 
947 	logical = blk_to_logical(inode, start_blk);
948 	phys = blk_to_logical(inode, map_bh.b_blocknr);
949 	size = map_bh.b_size;
950 	flags = 0;
951 	if (buffer_unwritten(&map_bh))
952 		flags = FIEMAP_EXTENT_UNWRITTEN;
953 
954 	start_blk += logical_to_blk(inode, size);
955 
956 prep_next:
957 	cond_resched();
958 	if (fatal_signal_pending(current))
959 		ret = -EINTR;
960 	else
961 		goto next;
962 out:
963 	if (ret == 1)
964 		ret = 0;
965 
966 	inode_unlock(inode);
967 	return ret;
968 }
969 
970 struct bio *f2fs_grab_bio(struct inode *inode, block_t blkaddr,
971 							unsigned nr_pages)
972 {
973 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
974 	struct fscrypt_ctx *ctx = NULL;
975 	struct block_device *bdev = sbi->sb->s_bdev;
976 	struct bio *bio;
977 
978 	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) {
979 		ctx = fscrypt_get_ctx(inode, GFP_NOFS);
980 		if (IS_ERR(ctx))
981 			return ERR_CAST(ctx);
982 
983 		/* wait the page to be moved by cleaning */
984 		f2fs_wait_on_encrypted_page_writeback(sbi, blkaddr);
985 	}
986 
987 	bio = bio_alloc(GFP_KERNEL, min_t(int, nr_pages, BIO_MAX_PAGES));
988 	if (!bio) {
989 		if (ctx)
990 			fscrypt_release_ctx(ctx);
991 		return ERR_PTR(-ENOMEM);
992 	}
993 	bio->bi_bdev = bdev;
994 	bio->bi_iter.bi_sector = SECTOR_FROM_BLOCK(blkaddr);
995 	bio->bi_end_io = f2fs_read_end_io;
996 	bio->bi_private = ctx;
997 
998 	return bio;
999 }
1000 
1001 /*
1002  * This function was originally taken from fs/mpage.c, and customized for f2fs.
1003  * Major change was from block_size == page_size in f2fs by default.
1004  */
1005 static int f2fs_mpage_readpages(struct address_space *mapping,
1006 			struct list_head *pages, struct page *page,
1007 			unsigned nr_pages)
1008 {
1009 	struct bio *bio = NULL;
1010 	unsigned page_idx;
1011 	sector_t last_block_in_bio = 0;
1012 	struct inode *inode = mapping->host;
1013 	const unsigned blkbits = inode->i_blkbits;
1014 	const unsigned blocksize = 1 << blkbits;
1015 	sector_t block_in_file;
1016 	sector_t last_block;
1017 	sector_t last_block_in_file;
1018 	sector_t block_nr;
1019 	struct f2fs_map_blocks map;
1020 
1021 	map.m_pblk = 0;
1022 	map.m_lblk = 0;
1023 	map.m_len = 0;
1024 	map.m_flags = 0;
1025 	map.m_next_pgofs = NULL;
1026 
1027 	for (page_idx = 0; nr_pages; page_idx++, nr_pages--) {
1028 
1029 		prefetchw(&page->flags);
1030 		if (pages) {
1031 			page = list_entry(pages->prev, struct page, lru);
1032 			list_del(&page->lru);
1033 			if (add_to_page_cache_lru(page, mapping,
1034 						  page->index,
1035 						  readahead_gfp_mask(mapping)))
1036 				goto next_page;
1037 		}
1038 
1039 		block_in_file = (sector_t)page->index;
1040 		last_block = block_in_file + nr_pages;
1041 		last_block_in_file = (i_size_read(inode) + blocksize - 1) >>
1042 								blkbits;
1043 		if (last_block > last_block_in_file)
1044 			last_block = last_block_in_file;
1045 
1046 		/*
1047 		 * Map blocks using the previous result first.
1048 		 */
1049 		if ((map.m_flags & F2FS_MAP_MAPPED) &&
1050 				block_in_file > map.m_lblk &&
1051 				block_in_file < (map.m_lblk + map.m_len))
1052 			goto got_it;
1053 
1054 		/*
1055 		 * Then do more f2fs_map_blocks() calls until we are
1056 		 * done with this page.
1057 		 */
1058 		map.m_flags = 0;
1059 
1060 		if (block_in_file < last_block) {
1061 			map.m_lblk = block_in_file;
1062 			map.m_len = last_block - block_in_file;
1063 
1064 			if (f2fs_map_blocks(inode, &map, 0,
1065 						F2FS_GET_BLOCK_READ))
1066 				goto set_error_page;
1067 		}
1068 got_it:
1069 		if ((map.m_flags & F2FS_MAP_MAPPED)) {
1070 			block_nr = map.m_pblk + block_in_file - map.m_lblk;
1071 			SetPageMappedToDisk(page);
1072 
1073 			if (!PageUptodate(page) && !cleancache_get_page(page)) {
1074 				SetPageUptodate(page);
1075 				goto confused;
1076 			}
1077 		} else {
1078 			zero_user_segment(page, 0, PAGE_SIZE);
1079 			if (!PageUptodate(page))
1080 				SetPageUptodate(page);
1081 			unlock_page(page);
1082 			goto next_page;
1083 		}
1084 
1085 		/*
1086 		 * This page will go to BIO.  Do we need to send this
1087 		 * BIO off first?
1088 		 */
1089 		if (bio && (last_block_in_bio != block_nr - 1)) {
1090 submit_and_realloc:
1091 			__submit_bio(F2FS_I_SB(inode), bio, DATA);
1092 			bio = NULL;
1093 		}
1094 		if (bio == NULL) {
1095 			bio = f2fs_grab_bio(inode, block_nr, nr_pages);
1096 			if (IS_ERR(bio)) {
1097 				bio = NULL;
1098 				goto set_error_page;
1099 			}
1100 			bio_set_op_attrs(bio, REQ_OP_READ, 0);
1101 		}
1102 
1103 		if (bio_add_page(bio, page, blocksize, 0) < blocksize)
1104 			goto submit_and_realloc;
1105 
1106 		last_block_in_bio = block_nr;
1107 		goto next_page;
1108 set_error_page:
1109 		SetPageError(page);
1110 		zero_user_segment(page, 0, PAGE_SIZE);
1111 		unlock_page(page);
1112 		goto next_page;
1113 confused:
1114 		if (bio) {
1115 			__submit_bio(F2FS_I_SB(inode), bio, DATA);
1116 			bio = NULL;
1117 		}
1118 		unlock_page(page);
1119 next_page:
1120 		if (pages)
1121 			put_page(page);
1122 	}
1123 	BUG_ON(pages && !list_empty(pages));
1124 	if (bio)
1125 		__submit_bio(F2FS_I_SB(inode), bio, DATA);
1126 	return 0;
1127 }
1128 
1129 static int f2fs_read_data_page(struct file *file, struct page *page)
1130 {
1131 	struct inode *inode = page->mapping->host;
1132 	int ret = -EAGAIN;
1133 
1134 	trace_f2fs_readpage(page, DATA);
1135 
1136 	/* If the file has inline data, try to read it directly */
1137 	if (f2fs_has_inline_data(inode))
1138 		ret = f2fs_read_inline_data(inode, page);
1139 	if (ret == -EAGAIN)
1140 		ret = f2fs_mpage_readpages(page->mapping, NULL, page, 1);
1141 	return ret;
1142 }
1143 
1144 static int f2fs_read_data_pages(struct file *file,
1145 			struct address_space *mapping,
1146 			struct list_head *pages, unsigned nr_pages)
1147 {
1148 	struct inode *inode = file->f_mapping->host;
1149 	struct page *page = list_entry(pages->prev, struct page, lru);
1150 
1151 	trace_f2fs_readpages(inode, page, nr_pages);
1152 
1153 	/* If the file has inline data, skip readpages */
1154 	if (f2fs_has_inline_data(inode))
1155 		return 0;
1156 
1157 	return f2fs_mpage_readpages(mapping, pages, NULL, nr_pages);
1158 }
1159 
1160 int do_write_data_page(struct f2fs_io_info *fio)
1161 {
1162 	struct page *page = fio->page;
1163 	struct inode *inode = page->mapping->host;
1164 	struct dnode_of_data dn;
1165 	int err = 0;
1166 
1167 	set_new_dnode(&dn, inode, NULL, NULL, 0);
1168 	err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
1169 	if (err)
1170 		return err;
1171 
1172 	fio->old_blkaddr = dn.data_blkaddr;
1173 
1174 	/* This page is already truncated */
1175 	if (fio->old_blkaddr == NULL_ADDR) {
1176 		ClearPageUptodate(page);
1177 		goto out_writepage;
1178 	}
1179 
1180 	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode)) {
1181 		gfp_t gfp_flags = GFP_NOFS;
1182 
1183 		/* wait for GCed encrypted page writeback */
1184 		f2fs_wait_on_encrypted_page_writeback(F2FS_I_SB(inode),
1185 							fio->old_blkaddr);
1186 retry_encrypt:
1187 		fio->encrypted_page = fscrypt_encrypt_page(inode, fio->page,
1188 								gfp_flags);
1189 		if (IS_ERR(fio->encrypted_page)) {
1190 			err = PTR_ERR(fio->encrypted_page);
1191 			if (err == -ENOMEM) {
1192 				/* flush pending ios and wait for a while */
1193 				f2fs_flush_merged_bios(F2FS_I_SB(inode));
1194 				congestion_wait(BLK_RW_ASYNC, HZ/50);
1195 				gfp_flags |= __GFP_NOFAIL;
1196 				err = 0;
1197 				goto retry_encrypt;
1198 			}
1199 			goto out_writepage;
1200 		}
1201 	}
1202 
1203 	set_page_writeback(page);
1204 
1205 	/*
1206 	 * If current allocation needs SSR,
1207 	 * it had better in-place writes for updated data.
1208 	 */
1209 	if (unlikely(fio->old_blkaddr != NEW_ADDR &&
1210 			!is_cold_data(page) &&
1211 			!IS_ATOMIC_WRITTEN_PAGE(page) &&
1212 			need_inplace_update(inode))) {
1213 		rewrite_data_page(fio);
1214 		set_inode_flag(inode, FI_UPDATE_WRITE);
1215 		trace_f2fs_do_write_data_page(page, IPU);
1216 	} else {
1217 		write_data_page(&dn, fio);
1218 		trace_f2fs_do_write_data_page(page, OPU);
1219 		set_inode_flag(inode, FI_APPEND_WRITE);
1220 		if (page->index == 0)
1221 			set_inode_flag(inode, FI_FIRST_BLOCK_WRITTEN);
1222 	}
1223 out_writepage:
1224 	f2fs_put_dnode(&dn);
1225 	return err;
1226 }
1227 
1228 static int f2fs_write_data_page(struct page *page,
1229 					struct writeback_control *wbc)
1230 {
1231 	struct inode *inode = page->mapping->host;
1232 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1233 	loff_t i_size = i_size_read(inode);
1234 	const pgoff_t end_index = ((unsigned long long) i_size)
1235 							>> PAGE_SHIFT;
1236 	loff_t psize = (page->index + 1) << PAGE_SHIFT;
1237 	unsigned offset = 0;
1238 	bool need_balance_fs = false;
1239 	int err = 0;
1240 	struct f2fs_io_info fio = {
1241 		.sbi = sbi,
1242 		.type = DATA,
1243 		.op = REQ_OP_WRITE,
1244 		.op_flags = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : 0,
1245 		.page = page,
1246 		.encrypted_page = NULL,
1247 	};
1248 
1249 	trace_f2fs_writepage(page, DATA);
1250 
1251 	if (page->index < end_index)
1252 		goto write;
1253 
1254 	/*
1255 	 * If the offset is out-of-range of file size,
1256 	 * this page does not have to be written to disk.
1257 	 */
1258 	offset = i_size & (PAGE_SIZE - 1);
1259 	if ((page->index >= end_index + 1) || !offset)
1260 		goto out;
1261 
1262 	zero_user_segment(page, offset, PAGE_SIZE);
1263 write:
1264 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
1265 		goto redirty_out;
1266 	if (f2fs_is_drop_cache(inode))
1267 		goto out;
1268 	/* we should not write 0'th page having journal header */
1269 	if (f2fs_is_volatile_file(inode) && (!page->index ||
1270 			(!wbc->for_reclaim &&
1271 			available_free_memory(sbi, BASE_CHECK))))
1272 		goto redirty_out;
1273 
1274 	/* we should bypass data pages to proceed the kworkder jobs */
1275 	if (unlikely(f2fs_cp_error(sbi))) {
1276 		mapping_set_error(page->mapping, -EIO);
1277 		goto out;
1278 	}
1279 
1280 	/* Dentry blocks are controlled by checkpoint */
1281 	if (S_ISDIR(inode->i_mode)) {
1282 		err = do_write_data_page(&fio);
1283 		goto done;
1284 	}
1285 
1286 	if (!wbc->for_reclaim)
1287 		need_balance_fs = true;
1288 	else if (has_not_enough_free_secs(sbi, 0))
1289 		goto redirty_out;
1290 
1291 	err = -EAGAIN;
1292 	f2fs_lock_op(sbi);
1293 	if (f2fs_has_inline_data(inode))
1294 		err = f2fs_write_inline_data(inode, page);
1295 	if (err == -EAGAIN)
1296 		err = do_write_data_page(&fio);
1297 	if (F2FS_I(inode)->last_disk_size < psize)
1298 		F2FS_I(inode)->last_disk_size = psize;
1299 	f2fs_unlock_op(sbi);
1300 done:
1301 	if (err && err != -ENOENT)
1302 		goto redirty_out;
1303 
1304 	clear_cold_data(page);
1305 out:
1306 	inode_dec_dirty_pages(inode);
1307 	if (err)
1308 		ClearPageUptodate(page);
1309 
1310 	if (wbc->for_reclaim) {
1311 		f2fs_submit_merged_bio_cond(sbi, NULL, page, 0, DATA, WRITE);
1312 		remove_dirty_inode(inode);
1313 	}
1314 
1315 	unlock_page(page);
1316 	f2fs_balance_fs(sbi, need_balance_fs);
1317 
1318 	if (unlikely(f2fs_cp_error(sbi)))
1319 		f2fs_submit_merged_bio(sbi, DATA, WRITE);
1320 
1321 	return 0;
1322 
1323 redirty_out:
1324 	redirty_page_for_writepage(wbc, page);
1325 	unlock_page(page);
1326 	return err;
1327 }
1328 
1329 /*
1330  * This function was copied from write_cche_pages from mm/page-writeback.c.
1331  * The major change is making write step of cold data page separately from
1332  * warm/hot data page.
1333  */
1334 static int f2fs_write_cache_pages(struct address_space *mapping,
1335 					struct writeback_control *wbc)
1336 {
1337 	int ret = 0;
1338 	int done = 0;
1339 	struct pagevec pvec;
1340 	int nr_pages;
1341 	pgoff_t uninitialized_var(writeback_index);
1342 	pgoff_t index;
1343 	pgoff_t end;		/* Inclusive */
1344 	pgoff_t done_index;
1345 	int cycled;
1346 	int range_whole = 0;
1347 	int tag;
1348 
1349 	pagevec_init(&pvec, 0);
1350 
1351 	if (wbc->range_cyclic) {
1352 		writeback_index = mapping->writeback_index; /* prev offset */
1353 		index = writeback_index;
1354 		if (index == 0)
1355 			cycled = 1;
1356 		else
1357 			cycled = 0;
1358 		end = -1;
1359 	} else {
1360 		index = wbc->range_start >> PAGE_SHIFT;
1361 		end = wbc->range_end >> PAGE_SHIFT;
1362 		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
1363 			range_whole = 1;
1364 		cycled = 1; /* ignore range_cyclic tests */
1365 	}
1366 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
1367 		tag = PAGECACHE_TAG_TOWRITE;
1368 	else
1369 		tag = PAGECACHE_TAG_DIRTY;
1370 retry:
1371 	if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
1372 		tag_pages_for_writeback(mapping, index, end);
1373 	done_index = index;
1374 	while (!done && (index <= end)) {
1375 		int i;
1376 
1377 		nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, tag,
1378 			      min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1);
1379 		if (nr_pages == 0)
1380 			break;
1381 
1382 		for (i = 0; i < nr_pages; i++) {
1383 			struct page *page = pvec.pages[i];
1384 
1385 			if (page->index > end) {
1386 				done = 1;
1387 				break;
1388 			}
1389 
1390 			done_index = page->index;
1391 
1392 			lock_page(page);
1393 
1394 			if (unlikely(page->mapping != mapping)) {
1395 continue_unlock:
1396 				unlock_page(page);
1397 				continue;
1398 			}
1399 
1400 			if (!PageDirty(page)) {
1401 				/* someone wrote it for us */
1402 				goto continue_unlock;
1403 			}
1404 
1405 			if (PageWriteback(page)) {
1406 				if (wbc->sync_mode != WB_SYNC_NONE)
1407 					f2fs_wait_on_page_writeback(page,
1408 								DATA, true);
1409 				else
1410 					goto continue_unlock;
1411 			}
1412 
1413 			BUG_ON(PageWriteback(page));
1414 			if (!clear_page_dirty_for_io(page))
1415 				goto continue_unlock;
1416 
1417 			ret = mapping->a_ops->writepage(page, wbc);
1418 			if (unlikely(ret)) {
1419 				done_index = page->index + 1;
1420 				done = 1;
1421 				break;
1422 			}
1423 
1424 			if (--wbc->nr_to_write <= 0 &&
1425 			    wbc->sync_mode == WB_SYNC_NONE) {
1426 				done = 1;
1427 				break;
1428 			}
1429 		}
1430 		pagevec_release(&pvec);
1431 		cond_resched();
1432 	}
1433 
1434 	if (!cycled && !done) {
1435 		cycled = 1;
1436 		index = 0;
1437 		end = writeback_index - 1;
1438 		goto retry;
1439 	}
1440 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
1441 		mapping->writeback_index = done_index;
1442 
1443 	return ret;
1444 }
1445 
1446 static int f2fs_write_data_pages(struct address_space *mapping,
1447 			    struct writeback_control *wbc)
1448 {
1449 	struct inode *inode = mapping->host;
1450 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1451 	struct blk_plug plug;
1452 	int ret;
1453 
1454 	/* deal with chardevs and other special file */
1455 	if (!mapping->a_ops->writepage)
1456 		return 0;
1457 
1458 	/* skip writing if there is no dirty page in this inode */
1459 	if (!get_dirty_pages(inode) && wbc->sync_mode == WB_SYNC_NONE)
1460 		return 0;
1461 
1462 	if (S_ISDIR(inode->i_mode) && wbc->sync_mode == WB_SYNC_NONE &&
1463 			get_dirty_pages(inode) < nr_pages_to_skip(sbi, DATA) &&
1464 			available_free_memory(sbi, DIRTY_DENTS))
1465 		goto skip_write;
1466 
1467 	/* skip writing during file defragment */
1468 	if (is_inode_flag_set(inode, FI_DO_DEFRAG))
1469 		goto skip_write;
1470 
1471 	/* during POR, we don't need to trigger writepage at all. */
1472 	if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
1473 		goto skip_write;
1474 
1475 	trace_f2fs_writepages(mapping->host, wbc, DATA);
1476 
1477 	blk_start_plug(&plug);
1478 	ret = f2fs_write_cache_pages(mapping, wbc);
1479 	blk_finish_plug(&plug);
1480 	/*
1481 	 * if some pages were truncated, we cannot guarantee its mapping->host
1482 	 * to detect pending bios.
1483 	 */
1484 	f2fs_submit_merged_bio(sbi, DATA, WRITE);
1485 
1486 	remove_dirty_inode(inode);
1487 	return ret;
1488 
1489 skip_write:
1490 	wbc->pages_skipped += get_dirty_pages(inode);
1491 	trace_f2fs_writepages(mapping->host, wbc, DATA);
1492 	return 0;
1493 }
1494 
1495 static void f2fs_write_failed(struct address_space *mapping, loff_t to)
1496 {
1497 	struct inode *inode = mapping->host;
1498 	loff_t i_size = i_size_read(inode);
1499 
1500 	if (to > i_size) {
1501 		truncate_pagecache(inode, i_size);
1502 		truncate_blocks(inode, i_size, true);
1503 	}
1504 }
1505 
1506 static int prepare_write_begin(struct f2fs_sb_info *sbi,
1507 			struct page *page, loff_t pos, unsigned len,
1508 			block_t *blk_addr, bool *node_changed)
1509 {
1510 	struct inode *inode = page->mapping->host;
1511 	pgoff_t index = page->index;
1512 	struct dnode_of_data dn;
1513 	struct page *ipage;
1514 	bool locked = false;
1515 	struct extent_info ei;
1516 	int err = 0;
1517 
1518 	/*
1519 	 * we already allocated all the blocks, so we don't need to get
1520 	 * the block addresses when there is no need to fill the page.
1521 	 */
1522 	if (!f2fs_has_inline_data(inode) && !f2fs_encrypted_inode(inode) &&
1523 					len == PAGE_SIZE)
1524 		return 0;
1525 
1526 	if (f2fs_has_inline_data(inode) ||
1527 			(pos & PAGE_MASK) >= i_size_read(inode)) {
1528 		f2fs_lock_op(sbi);
1529 		locked = true;
1530 	}
1531 restart:
1532 	/* check inline_data */
1533 	ipage = get_node_page(sbi, inode->i_ino);
1534 	if (IS_ERR(ipage)) {
1535 		err = PTR_ERR(ipage);
1536 		goto unlock_out;
1537 	}
1538 
1539 	set_new_dnode(&dn, inode, ipage, ipage, 0);
1540 
1541 	if (f2fs_has_inline_data(inode)) {
1542 		if (pos + len <= MAX_INLINE_DATA) {
1543 			read_inline_data(page, ipage);
1544 			set_inode_flag(inode, FI_DATA_EXIST);
1545 			if (inode->i_nlink)
1546 				set_inline_node(ipage);
1547 		} else {
1548 			err = f2fs_convert_inline_page(&dn, page);
1549 			if (err)
1550 				goto out;
1551 			if (dn.data_blkaddr == NULL_ADDR)
1552 				err = f2fs_get_block(&dn, index);
1553 		}
1554 	} else if (locked) {
1555 		err = f2fs_get_block(&dn, index);
1556 	} else {
1557 		if (f2fs_lookup_extent_cache(inode, index, &ei)) {
1558 			dn.data_blkaddr = ei.blk + index - ei.fofs;
1559 		} else {
1560 			/* hole case */
1561 			err = get_dnode_of_data(&dn, index, LOOKUP_NODE);
1562 			if (err || dn.data_blkaddr == NULL_ADDR) {
1563 				f2fs_put_dnode(&dn);
1564 				f2fs_lock_op(sbi);
1565 				locked = true;
1566 				goto restart;
1567 			}
1568 		}
1569 	}
1570 
1571 	/* convert_inline_page can make node_changed */
1572 	*blk_addr = dn.data_blkaddr;
1573 	*node_changed = dn.node_changed;
1574 out:
1575 	f2fs_put_dnode(&dn);
1576 unlock_out:
1577 	if (locked)
1578 		f2fs_unlock_op(sbi);
1579 	return err;
1580 }
1581 
1582 static int f2fs_write_begin(struct file *file, struct address_space *mapping,
1583 		loff_t pos, unsigned len, unsigned flags,
1584 		struct page **pagep, void **fsdata)
1585 {
1586 	struct inode *inode = mapping->host;
1587 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1588 	struct page *page = NULL;
1589 	pgoff_t index = ((unsigned long long) pos) >> PAGE_SHIFT;
1590 	bool need_balance = false;
1591 	block_t blkaddr = NULL_ADDR;
1592 	int err = 0;
1593 
1594 	trace_f2fs_write_begin(inode, pos, len, flags);
1595 
1596 	/*
1597 	 * We should check this at this moment to avoid deadlock on inode page
1598 	 * and #0 page. The locking rule for inline_data conversion should be:
1599 	 * lock_page(page #0) -> lock_page(inode_page)
1600 	 */
1601 	if (index != 0) {
1602 		err = f2fs_convert_inline_inode(inode);
1603 		if (err)
1604 			goto fail;
1605 	}
1606 repeat:
1607 	page = grab_cache_page_write_begin(mapping, index, flags);
1608 	if (!page) {
1609 		err = -ENOMEM;
1610 		goto fail;
1611 	}
1612 
1613 	*pagep = page;
1614 
1615 	err = prepare_write_begin(sbi, page, pos, len,
1616 					&blkaddr, &need_balance);
1617 	if (err)
1618 		goto fail;
1619 
1620 	if (need_balance && has_not_enough_free_secs(sbi, 0)) {
1621 		unlock_page(page);
1622 		f2fs_balance_fs(sbi, true);
1623 		lock_page(page);
1624 		if (page->mapping != mapping) {
1625 			/* The page got truncated from under us */
1626 			f2fs_put_page(page, 1);
1627 			goto repeat;
1628 		}
1629 	}
1630 
1631 	f2fs_wait_on_page_writeback(page, DATA, false);
1632 
1633 	/* wait for GCed encrypted page writeback */
1634 	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
1635 		f2fs_wait_on_encrypted_page_writeback(sbi, blkaddr);
1636 
1637 	if (len == PAGE_SIZE)
1638 		goto out_update;
1639 	if (PageUptodate(page))
1640 		goto out_clear;
1641 
1642 	if ((pos & PAGE_MASK) >= i_size_read(inode)) {
1643 		unsigned start = pos & (PAGE_SIZE - 1);
1644 		unsigned end = start + len;
1645 
1646 		/* Reading beyond i_size is simple: memset to zero */
1647 		zero_user_segments(page, 0, start, end, PAGE_SIZE);
1648 		goto out_update;
1649 	}
1650 
1651 	if (blkaddr == NEW_ADDR) {
1652 		zero_user_segment(page, 0, PAGE_SIZE);
1653 	} else {
1654 		struct bio *bio;
1655 
1656 		bio = f2fs_grab_bio(inode, blkaddr, 1);
1657 		if (IS_ERR(bio)) {
1658 			err = PTR_ERR(bio);
1659 			goto fail;
1660 		}
1661 		bio_set_op_attrs(bio, REQ_OP_READ, READ_SYNC);
1662 		if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) {
1663 			bio_put(bio);
1664 			err = -EFAULT;
1665 			goto fail;
1666 		}
1667 
1668 		__submit_bio(sbi, bio, DATA);
1669 
1670 		lock_page(page);
1671 		if (unlikely(page->mapping != mapping)) {
1672 			f2fs_put_page(page, 1);
1673 			goto repeat;
1674 		}
1675 		if (unlikely(!PageUptodate(page))) {
1676 			err = -EIO;
1677 			goto fail;
1678 		}
1679 	}
1680 out_update:
1681 	if (!PageUptodate(page))
1682 		SetPageUptodate(page);
1683 out_clear:
1684 	clear_cold_data(page);
1685 	return 0;
1686 
1687 fail:
1688 	f2fs_put_page(page, 1);
1689 	f2fs_write_failed(mapping, pos + len);
1690 	return err;
1691 }
1692 
1693 static int f2fs_write_end(struct file *file,
1694 			struct address_space *mapping,
1695 			loff_t pos, unsigned len, unsigned copied,
1696 			struct page *page, void *fsdata)
1697 {
1698 	struct inode *inode = page->mapping->host;
1699 
1700 	trace_f2fs_write_end(inode, pos, len, copied);
1701 
1702 	set_page_dirty(page);
1703 	f2fs_put_page(page, 1);
1704 
1705 	if (pos + copied > i_size_read(inode))
1706 		f2fs_i_size_write(inode, pos + copied);
1707 
1708 	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
1709 	return copied;
1710 }
1711 
1712 static int check_direct_IO(struct inode *inode, struct iov_iter *iter,
1713 			   loff_t offset)
1714 {
1715 	unsigned blocksize_mask = inode->i_sb->s_blocksize - 1;
1716 
1717 	if (offset & blocksize_mask)
1718 		return -EINVAL;
1719 
1720 	if (iov_iter_alignment(iter) & blocksize_mask)
1721 		return -EINVAL;
1722 
1723 	return 0;
1724 }
1725 
1726 static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
1727 {
1728 	struct address_space *mapping = iocb->ki_filp->f_mapping;
1729 	struct inode *inode = mapping->host;
1730 	size_t count = iov_iter_count(iter);
1731 	loff_t offset = iocb->ki_pos;
1732 	int rw = iov_iter_rw(iter);
1733 	int err;
1734 
1735 	err = check_direct_IO(inode, iter, offset);
1736 	if (err)
1737 		return err;
1738 
1739 	if (f2fs_encrypted_inode(inode) && S_ISREG(inode->i_mode))
1740 		return 0;
1741 	if (test_opt(F2FS_I_SB(inode), LFS))
1742 		return 0;
1743 
1744 	trace_f2fs_direct_IO_enter(inode, offset, count, rw);
1745 
1746 	down_read(&F2FS_I(inode)->dio_rwsem[rw]);
1747 	err = blockdev_direct_IO(iocb, inode, iter, get_data_block_dio);
1748 	up_read(&F2FS_I(inode)->dio_rwsem[rw]);
1749 
1750 	if (rw == WRITE) {
1751 		if (err > 0)
1752 			set_inode_flag(inode, FI_UPDATE_WRITE);
1753 		else if (err < 0)
1754 			f2fs_write_failed(mapping, offset + count);
1755 	}
1756 
1757 	trace_f2fs_direct_IO_exit(inode, offset, count, rw, err);
1758 
1759 	return err;
1760 }
1761 
1762 void f2fs_invalidate_page(struct page *page, unsigned int offset,
1763 							unsigned int length)
1764 {
1765 	struct inode *inode = page->mapping->host;
1766 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
1767 
1768 	if (inode->i_ino >= F2FS_ROOT_INO(sbi) &&
1769 		(offset % PAGE_SIZE || length != PAGE_SIZE))
1770 		return;
1771 
1772 	if (PageDirty(page)) {
1773 		if (inode->i_ino == F2FS_META_INO(sbi))
1774 			dec_page_count(sbi, F2FS_DIRTY_META);
1775 		else if (inode->i_ino == F2FS_NODE_INO(sbi))
1776 			dec_page_count(sbi, F2FS_DIRTY_NODES);
1777 		else
1778 			inode_dec_dirty_pages(inode);
1779 	}
1780 
1781 	/* This is atomic written page, keep Private */
1782 	if (IS_ATOMIC_WRITTEN_PAGE(page))
1783 		return;
1784 
1785 	set_page_private(page, 0);
1786 	ClearPagePrivate(page);
1787 }
1788 
1789 int f2fs_release_page(struct page *page, gfp_t wait)
1790 {
1791 	/* If this is dirty page, keep PagePrivate */
1792 	if (PageDirty(page))
1793 		return 0;
1794 
1795 	/* This is atomic written page, keep Private */
1796 	if (IS_ATOMIC_WRITTEN_PAGE(page))
1797 		return 0;
1798 
1799 	set_page_private(page, 0);
1800 	ClearPagePrivate(page);
1801 	return 1;
1802 }
1803 
1804 /*
1805  * This was copied from __set_page_dirty_buffers which gives higher performance
1806  * in very high speed storages. (e.g., pmem)
1807  */
1808 void f2fs_set_page_dirty_nobuffers(struct page *page)
1809 {
1810 	struct address_space *mapping = page->mapping;
1811 	unsigned long flags;
1812 
1813 	if (unlikely(!mapping))
1814 		return;
1815 
1816 	spin_lock(&mapping->private_lock);
1817 	lock_page_memcg(page);
1818 	SetPageDirty(page);
1819 	spin_unlock(&mapping->private_lock);
1820 
1821 	spin_lock_irqsave(&mapping->tree_lock, flags);
1822 	WARN_ON_ONCE(!PageUptodate(page));
1823 	account_page_dirtied(page, mapping);
1824 	radix_tree_tag_set(&mapping->page_tree,
1825 			page_index(page), PAGECACHE_TAG_DIRTY);
1826 	spin_unlock_irqrestore(&mapping->tree_lock, flags);
1827 	unlock_page_memcg(page);
1828 
1829 	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
1830 	return;
1831 }
1832 
1833 static int f2fs_set_data_page_dirty(struct page *page)
1834 {
1835 	struct address_space *mapping = page->mapping;
1836 	struct inode *inode = mapping->host;
1837 
1838 	trace_f2fs_set_page_dirty(page, DATA);
1839 
1840 	if (!PageUptodate(page))
1841 		SetPageUptodate(page);
1842 
1843 	if (f2fs_is_atomic_file(inode)) {
1844 		if (!IS_ATOMIC_WRITTEN_PAGE(page)) {
1845 			register_inmem_page(inode, page);
1846 			return 1;
1847 		}
1848 		/*
1849 		 * Previously, this page has been registered, we just
1850 		 * return here.
1851 		 */
1852 		return 0;
1853 	}
1854 
1855 	if (!PageDirty(page)) {
1856 		f2fs_set_page_dirty_nobuffers(page);
1857 		update_dirty_page(inode, page);
1858 		return 1;
1859 	}
1860 	return 0;
1861 }
1862 
1863 static sector_t f2fs_bmap(struct address_space *mapping, sector_t block)
1864 {
1865 	struct inode *inode = mapping->host;
1866 
1867 	if (f2fs_has_inline_data(inode))
1868 		return 0;
1869 
1870 	/* make sure allocating whole blocks */
1871 	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
1872 		filemap_write_and_wait(mapping);
1873 
1874 	return generic_block_bmap(mapping, block, get_data_block_bmap);
1875 }
1876 
1877 const struct address_space_operations f2fs_dblock_aops = {
1878 	.readpage	= f2fs_read_data_page,
1879 	.readpages	= f2fs_read_data_pages,
1880 	.writepage	= f2fs_write_data_page,
1881 	.writepages	= f2fs_write_data_pages,
1882 	.write_begin	= f2fs_write_begin,
1883 	.write_end	= f2fs_write_end,
1884 	.set_page_dirty	= f2fs_set_data_page_dirty,
1885 	.invalidatepage	= f2fs_invalidate_page,
1886 	.releasepage	= f2fs_release_page,
1887 	.direct_IO	= f2fs_direct_IO,
1888 	.bmap		= f2fs_bmap,
1889 };
1890