fs: Convert aops->write_begin to take a folio

Convert all callers from working on a page to working on one page
of a folio (support for working on an entire folio can come later).
Removes a lot of folio->page->folio conversions.

Reviewed-by: Josef Bacik <[email protected]>
Signed-off-by: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
Signed-off-by: Namjae Jeon <[email protected]>

file.c

@@ -635,25 +635,37 @@ static int exfat_file_zeroed_range(struct file *file, loff_t start, loff_t end)
 
 	while (start < end) {
 		u32 zerofrom, len;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 12, 0)
+		struct folio *folio;
+#else
 		struct page *page = NULL;
+#endif
 
 		zerofrom = start & (PAGE_SIZE - 1);
 		len = PAGE_SIZE - zerofrom;
 		if (start + len > end)
 			len = end - start;
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 0, 0)
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 12, 0)
+		err = ops->write_begin(file, mapping, start, len, &folio, NULL);
+#else
 		err = ops->write_begin(file, mapping, start, len, &page, NULL);
+#endif
 #else
 		err = ops->write_begin(file, mapping, start, len, 0, &page, NULL);
 #endif
 		if (err)
 			goto out;
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 12, 0)
+		folio_zero_range(folio, offset_in_folio(folio, start), len);
+#else
 		zero_user_segment(page, zerofrom, zerofrom + len);
+#endif
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 12, 0)
-		err = ops->write_end(file, mapping, start, len, len, page_folio(page), NULL);
+		err = ops->write_end(file, mapping, start, len, len, folio, NULL);
 #else
 		err = ops->write_end(file, mapping, start, len, len, page, NULL);
 #endif

inode.c

@@ -493,7 +493,11 @@ static void exfat_write_failed(struct address_space *mapping, loff_t to)
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 19, 0)
 static int exfat_write_begin(struct file *file, struct address_space *mapping,
 		loff_t pos, unsigned int len,
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 12, 0)
+		struct folio **foliop, void **fsdata)
+#else
 		struct page **pagep, void **fsdata)
+#endif
 #else
 static int exfat_write_begin(struct file *file, struct address_space *mapping,
 		loff_t pos, unsigned int len, unsigned int flags,
@@ -502,12 +506,16 @@ static int exfat_write_begin(struct file *file, struct address_space *mapping,
 {
 	int ret;
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 12, 0)
+	ret = block_write_begin(mapping, pos, len, foliop, exfat_get_block);
+#else
 	*pagep = NULL;
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 19, 0)
 	ret = block_write_begin(mapping, pos, len, pagep, exfat_get_block);
 #else
 	ret = block_write_begin(mapping, pos, len, flags, pagep,
 				exfat_get_block);
+#endif
 #endif
 	if (ret < 0)
 		exfat_write_failed(mapping, pos+len);