[PATCH v2 08/27] gfs2: Convert gfs2_getjdatabuf to use a folio

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

Use the folio APIs, saving four hidden calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
 fs/gfs2/meta_io.c | 22 ++++++++--------------
 1 file changed, 8 insertions(+), 14 deletions(-)

diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index f1fac1b45059..f6d40d51f5ed 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -400,26 +400,20 @@ static struct buffer_head *gfs2_getjdatabuf(struct gfs2_inode *ip, u64 blkno)
 {
 	struct address_space *mapping = ip->i_inode.i_mapping;
 	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
-	struct page *page;
+	struct folio *folio;
 	struct buffer_head *bh;
 	unsigned int shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift;
 	unsigned long index = blkno >> shift; /* convert block to page */
 	unsigned int bufnum = blkno - (index << shift);
 
-	page = find_get_page_flags(mapping, index, FGP_LOCK|FGP_ACCESSED);
-	if (!page)
-		return NULL;
-	if (!page_has_buffers(page)) {
-		unlock_page(page);
-		put_page(page);
+	folio = __filemap_get_folio(mapping, index, FGP_LOCK | FGP_ACCESSED, 0);
+	if (IS_ERR(folio))
 		return NULL;
-	}
-	/* Locate header for our buffer within our page */
-	for (bh = page_buffers(page); bufnum--; bh = bh->b_this_page)
-		/* Do nothing */;
-	get_bh(bh);
-	unlock_page(page);
-	put_page(page);
+	bh = folio_buffers(folio);
+	if (bh)
+		bh = get_nth_bh(bh, bufnum);
+	folio_unlock(folio);
+	folio_put(folio);
 	return bh;
 }
 
-- 
2.40.1