orangefs: Convert orangefs to read_folio

This is a full conversion which should be large folio ready, although
I have not tested it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

fs/orangefs/inode.c

@@ -288,40 +288,39 @@ static void orangefs_readahead(struct readahead_control *rac)
 	}
 }
 
-static int orangefs_readpage(struct file *file, struct page *page)
+static int orangefs_read_folio(struct file *file, struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
-	struct inode *inode = page->mapping->host;
+	struct inode *inode = folio->mapping->host;
 	struct iov_iter iter;
 	struct bio_vec bv;
 	ssize_t ret;
-	loff_t off; /* offset into this page */
+	loff_t off; /* offset of this folio in the file */
 
 	if (folio_test_dirty(folio))
 		orangefs_launder_folio(folio);
 
-	off = page_offset(page);
-	bv.bv_page = page;
-	bv.bv_len = PAGE_SIZE;
+	off = folio_pos(folio);
+	bv.bv_page = &folio->page;
+	bv.bv_len = folio_size(folio);
 	bv.bv_offset = 0;
-	iov_iter_bvec(&iter, READ, &bv, 1, PAGE_SIZE);
+	iov_iter_bvec(&iter, READ, &bv, 1, folio_size(folio));
 
 	ret = wait_for_direct_io(ORANGEFS_IO_READ, inode, &off, &iter,
-	    PAGE_SIZE, inode->i_size, NULL, NULL, file);
+			folio_size(folio), inode->i_size, NULL, NULL, file);
 	/* this will only zero remaining unread portions of the page data */
 	iov_iter_zero(~0U, &iter);
 	/* takes care of potential aliasing */
-	flush_dcache_page(page);
+	flush_dcache_folio(folio);
 	if (ret < 0) {
-		SetPageError(page);
+		folio_set_error(folio);
 	} else {
-		SetPageUptodate(page);
-		if (PageError(page))
-			ClearPageError(page);
+		folio_mark_uptodate(folio);
+		if (folio_test_error(folio))
+			folio_clear_error(folio);
 		ret = 0;
 	}
-	/* unlock the page after the ->readpage() routine completes */
-	unlock_page(page);
+	/* unlock the folio after the ->read_folio() routine completes */
+	folio_unlock(folio);
         return ret;
 }
 
@@ -631,7 +630,7 @@ static ssize_t orangefs_direct_IO(struct kiocb *iocb,
 static const struct address_space_operations orangefs_address_operations = {
 	.writepage = orangefs_writepage,
 	.readahead = orangefs_readahead,
-	.readpage = orangefs_readpage,
+	.read_folio = orangefs_read_folio,
 	.writepages = orangefs_writepages,
 	.dirty_folio = filemap_dirty_folio,
 	.write_begin = orangefs_write_begin,