jfs: Convert __get_metapage to use a folio

Remove four hidden calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>

Author: Matthew Wilcox (Oracle)

fs/jfs/jfs_metapage.c

@@ -577,7 +577,7 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 	int l2bsize;
 	struct address_space *mapping;
 	struct metapage *mp = NULL;
-	struct page *page;
+	struct folio *folio;
 	unsigned long page_index;
 	unsigned long page_offset;
 
@@ -608,22 +608,22 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 	}
 
 	if (new && (PSIZE == PAGE_SIZE)) {
-		page = grab_cache_page(mapping, page_index);
-		if (!page) {
-			jfs_err("grab_cache_page failed!");
+		folio = filemap_grab_folio(mapping, page_index);
+		if (IS_ERR(folio)) {
+			jfs_err("filemap_grab_folio failed!");
 			return NULL;
 		}
-		SetPageUptodate(page);
+		folio_mark_uptodate(folio);
 	} else {
-		page = read_mapping_page(mapping, page_index, NULL);
-		if (IS_ERR(page)) {
+		folio = read_mapping_folio(mapping, page_index, NULL);
+		if (IS_ERR(folio)) {
 			jfs_err("read_mapping_page failed!");
 			return NULL;
 		}
-		lock_page(page);
+		folio_lock(folio);
 	}
 
-	mp = page_to_mp(page, page_offset);
+	mp = page_to_mp(&folio->page, page_offset);
 	if (mp) {
 		if (mp->logical_size != size) {
 			jfs_error(inode->i_sb,
@@ -649,16 +649,16 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 		mp = alloc_metapage(GFP_NOFS);
 		if (!mp)
 			goto unlock;
-		mp->page = page;
+		mp->page = &folio->page;
 		mp->sb = inode->i_sb;
 		mp->flag = 0;
 		mp->xflag = COMMIT_PAGE;
 		mp->count = 1;
 		mp->nohomeok = 0;
 		mp->logical_size = size;
-		mp->data = page_address(page) + page_offset;
+		mp->data = folio_address(folio) + page_offset;
 		mp->index = lblock;
-		if (unlikely(insert_metapage(page, mp))) {
+		if (unlikely(insert_metapage(&folio->page, mp))) {
 			free_metapage(mp);
 			goto unlock;
 		}
@@ -670,12 +670,12 @@ struct metapage *__get_metapage(struct inode *inode, unsigned long lblock,
 		memset(mp->data, 0, PSIZE);
 	}
 
-	unlock_page(page);
+	folio_unlock(folio);
 	jfs_info("__get_metapage: returning = 0x%p data = 0x%p", mp, mp->data);
 	return mp;
 
 unlock:
-	unlock_page(page);
+	folio_unlock(folio);
 	return NULL;
 }