f2fs: convert f2fs_write_begin() to use folio

Convert to use folio, so that we can get rid of 'page->index' to
prepare for removal of 'index' field in structure page [1].

[1] https://lore.kernel.org/all/Zp8fgUSIBGQ1TN0D@casper.infradead.org/

Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Chao Yu <chao@kernel.org>
Reviewed-by: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/data.c

@@ -3378,11 +3378,11 @@ void f2fs_write_failed(struct inode *inode, loff_t to)
 }
 
 static int prepare_write_begin(struct f2fs_sb_info *sbi,
-			struct page *page, loff_t pos, unsigned len,
+			struct folio *folio, loff_t pos, unsigned int len,
 			block_t *blk_addr, bool *node_changed)
 {
-	struct inode *inode = page->mapping->host;
-	pgoff_t index = page->index;
+	struct inode *inode = folio->mapping->host;
+	pgoff_t index = folio->index;
 	struct dnode_of_data dn;
 	struct page *ipage;
 	bool locked = false;
@@ -3419,13 +3419,13 @@ static int prepare_write_begin(struct f2fs_sb_info *sbi,
 
 	if (f2fs_has_inline_data(inode)) {
 		if (pos + len <= MAX_INLINE_DATA(inode)) {
-			f2fs_do_read_inline_data(page_folio(page), ipage);
+			f2fs_do_read_inline_data(folio, ipage);
 			set_inode_flag(inode, FI_DATA_EXIST);
 			if (inode->i_nlink)
 				set_page_private_inline(ipage);
 			goto out;
 		}
-		err = f2fs_convert_inline_page(&dn, page);
+		err = f2fs_convert_inline_page(&dn, folio_page(folio, 0));
 		if (err || dn.data_blkaddr != NULL_ADDR)
 			goto out;
 	}
@@ -3518,12 +3518,12 @@ static int __reserve_data_block(struct inode *inode, pgoff_t index,
 }
 
 static int prepare_atomic_write_begin(struct f2fs_sb_info *sbi,
-			struct page *page, loff_t pos, unsigned int len,
+			struct folio *folio, loff_t pos, unsigned int len,
 			block_t *blk_addr, bool *node_changed, bool *use_cow)
 {
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 	struct inode *cow_inode = F2FS_I(inode)->cow_inode;
-	pgoff_t index = page->index;
+	pgoff_t index = folio->index;
 	int err = 0;
 	block_t ori_blk_addr = NULL_ADDR;
 
@@ -3566,6 +3566,7 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 	struct inode *inode = mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct page *page = NULL;
+	struct folio *folio;
 	pgoff_t index = ((unsigned long long) pos) >> PAGE_SHIFT;
 	bool need_balance = false;
 	bool use_cow = false;
@@ -3625,22 +3626,23 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 	/* TODO: cluster can be compressed due to race with .writepage */
 
 	*pagep = page;
+	folio = page_folio(page);
 
 	if (f2fs_is_atomic_file(inode))
-		err = prepare_atomic_write_begin(sbi, page, pos, len,
+		err = prepare_atomic_write_begin(sbi, folio, pos, len,
 					&blkaddr, &need_balance, &use_cow);
 	else
-		err = prepare_write_begin(sbi, page, pos, len,
+		err = prepare_write_begin(sbi, folio, pos, len,
 					&blkaddr, &need_balance);
 	if (err)
 		goto fail;
 
 	if (need_balance && !IS_NOQUOTA(inode) &&
 			has_not_enough_free_secs(sbi, 0, 0)) {
-		unlock_page(page);
+		folio_unlock(folio);
 		f2fs_balance_fs(sbi, true);
-		lock_page(page);
-		if (page->mapping != mapping) {
+		folio_lock(folio);
+		if (folio->mapping != mapping) {
 			/* The page got truncated from under us */
 			f2fs_put_page(page, 1);
 			goto repeat;
@@ -3649,18 +3651,18 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 
 	f2fs_wait_on_page_writeback(page, DATA, false, true);
 
-	if (len == PAGE_SIZE || PageUptodate(page))
+	if (len == PAGE_SIZE || folio_test_uptodate(folio))
 		return 0;
 
 	if (!(pos & (PAGE_SIZE - 1)) && (pos + len) >= i_size_read(inode) &&
 	    !f2fs_verity_in_progress(inode)) {
-		zero_user_segment(page, len, PAGE_SIZE);
+		folio_zero_segment(folio, len, folio_size(folio));
 		return 0;
 	}
 
 	if (blkaddr == NEW_ADDR) {
-		zero_user_segment(page, 0, PAGE_SIZE);
-		SetPageUptodate(page);
+		folio_zero_segment(folio, 0, folio_size(folio));
+		folio_mark_uptodate(folio);
 	} else {
 		if (!f2fs_is_valid_blkaddr(sbi, blkaddr,
 				DATA_GENERIC_ENHANCE_READ)) {
@@ -3669,16 +3671,16 @@ static int f2fs_write_begin(struct file *file, struct address_space *mapping,
 		}
 		err = f2fs_submit_page_read(use_cow ?
 				F2FS_I(inode)->cow_inode : inode,
-				page_folio(page), blkaddr, 0, true);
+				folio, blkaddr, 0, true);
 		if (err)
 			goto fail;
 
-		lock_page(page);
-		if (unlikely(page->mapping != mapping)) {
+		folio_lock(folio);
+		if (unlikely(folio->mapping != mapping)) {
 			f2fs_put_page(page, 1);
 			goto repeat;
 		}
-		if (unlikely(!PageUptodate(page))) {
+		if (unlikely(!folio_test_uptodate(folio))) {
 			err = -EIO;
 			goto fail;
 		}