nilfs2: convert nilfs_add_link() to use a folio

Remove six calls to compound_head() by using the folio API.

Link: https://lkml.kernel.org/r/20231127143036.2425-14-konishi.ryusuke@gmail.comSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/nilfs2/dir.c

@@ -439,30 +439,28 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode)
 	unsigned int chunk_size = nilfs_chunk_size(dir);
 	unsigned int reclen = NILFS_DIR_REC_LEN(namelen);
 	unsigned short rec_len, name_len;
-	struct page *page = NULL;
+	struct folio *folio = NULL;
 	struct nilfs_dir_entry *de;
 	unsigned long npages = dir_pages(dir);
 	unsigned long n;
-	char *kaddr;
-	unsigned int from, to;
+	size_t from, to;
 	int err;
 
 	/*
 	 * We take care of directory expansion in the same loop.
-	 * This code plays outside i_size, so it locks the page
+	 * This code plays outside i_size, so it locks the folio
 	 * to protect that region.
 	 */
 	for (n = 0; n <= npages; n++) {
+		char *kaddr = nilfs_get_folio(dir, n, &folio);
 		char *dir_end;
 
-		kaddr = nilfs_get_page(dir, n, &page);
-		err = PTR_ERR(kaddr);
 		if (IS_ERR(kaddr))
-			goto out;
-		lock_page(page);
+			return PTR_ERR(kaddr);
+		folio_lock(folio);
 		dir_end = kaddr + nilfs_last_byte(dir, n);
 		de = (struct nilfs_dir_entry *)kaddr;
-		kaddr += PAGE_SIZE - reclen;
+		kaddr += folio_size(folio) - reclen;
 		while ((char *)de <= kaddr) {
 			if ((char *)de == dir_end) {
 				/* We hit i_size */
@@ -489,16 +487,16 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode)
 				goto got_it;
 			de = (struct nilfs_dir_entry *)((char *)de + rec_len);
 		}
-		unlock_page(page);
-		unmap_and_put_page(page, kaddr);
+		folio_unlock(folio);
+		folio_release_kmap(folio, kaddr);
 	}
 	BUG();
 	return -EINVAL;
 
 got_it:
-	from = offset_in_page(de);
+	from = offset_in_folio(folio, de);
 	to = from + rec_len;
-	err = nilfs_prepare_chunk(page, from, to);
+	err = nilfs_prepare_chunk(&folio->page, from, to);
 	if (err)
 		goto out_unlock;
 	if (de->inode) {
@@ -513,16 +511,15 @@ int nilfs_add_link(struct dentry *dentry, struct inode *inode)
 	memcpy(de->name, name, namelen);
 	de->inode = cpu_to_le64(inode->i_ino);
 	nilfs_set_de_type(de, inode);
-	nilfs_commit_chunk(page, page->mapping, from, to);
+	nilfs_commit_chunk(&folio->page, folio->mapping, from, to);
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 	nilfs_mark_inode_dirty(dir);
 	/* OFFSET_CACHE */
 out_put:
-	unmap_and_put_page(page, de);
-out:
+	folio_release_kmap(folio, de);
 	return err;
 out_unlock:
-	unlock_page(page);
+	folio_unlock(folio);
 	goto out_put;
 }