From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Since nilfs2 has a ->writepages operation already, ->writepage is only
called by the migration code.  If we add a ->migrate_folio operation,
it won't even be used for that and so it can be deleted.

[ konishi.ryusuke: fixed panic by using buffer_migrate_folio_norefs ]
Link: https://lkml.kernel.org/r/20241002150036.1339475-2-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
---
 fs/nilfs2/inode.c | 33 +--------------------------------
 1 file changed, 1 insertion(+), 32 deletions(-)

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index be6acf6e2bfc..c24f06268010 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -170,37 +170,6 @@ static int nilfs_writepages(struct address_space *mapping,
 	return err;
 }
 
-static int nilfs_writepage(struct page *page, struct writeback_control *wbc)
-{
-	struct folio *folio = page_folio(page);
-	struct inode *inode = folio->mapping->host;
-	int err;
-
-	if (sb_rdonly(inode->i_sb)) {
-		/*
-		 * It means that filesystem was remounted in read-only
-		 * mode because of error or metadata corruption. But we
-		 * have dirty pages that try to be flushed in background.
-		 * So, here we simply discard this dirty page.
-		 */
-		nilfs_clear_folio_dirty(folio);
-		folio_unlock(folio);
-		return -EROFS;
-	}
-
-	folio_redirty_for_writepage(wbc, folio);
-	folio_unlock(folio);
-
-	if (wbc->sync_mode == WB_SYNC_ALL) {
-		err = nilfs_construct_segment(inode->i_sb);
-		if (unlikely(err))
-			return err;
-	} else if (wbc->for_reclaim)
-		nilfs_flush_segment(inode->i_sb, inode->i_ino);
-
-	return 0;
-}
-
 static bool nilfs_dirty_folio(struct address_space *mapping,
 		struct folio *folio)
 {
@@ -295,7 +264,6 @@ nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 }
 
 const struct address_space_operations nilfs_aops = {
-	.writepage		= nilfs_writepage,
 	.read_folio		= nilfs_read_folio,
 	.writepages		= nilfs_writepages,
 	.dirty_folio		= nilfs_dirty_folio,
@@ -304,6 +272,7 @@ const struct address_space_operations nilfs_aops = {
 	.write_end		= nilfs_write_end,
 	.invalidate_folio	= block_invalidate_folio,
 	.direct_IO		= nilfs_direct_IO,
+	.migrate_folio		= buffer_migrate_folio_norefs,
 	.is_partially_uptodate  = block_is_partially_uptodate,
 };
 
-- 
2.43.0