[PATCH v2 4/6] iomap: correct the dirty length in page mkwrite

[Zhang Yi <yi.zhang@huaweicloud.com>]

From: Zhang Yi <yi.zhang@huawei.com>

When doing page mkwrite, iomap_folio_mkwrite_iter() dirty the entire
folio by folio_mark_dirty() even the map length is shorter than one
folio. However, on the filesystem with more than one blocks per folio,
we'd better to only set counterpart block's dirty bit according to
iomap_length(), so open code folio_mark_dirty() and pass the correct
length.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/iomap/buffered-io.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 79031b7517e5..ac762de9a27f 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1492,7 +1492,10 @@ static loff_t iomap_folio_mkwrite_iter(struct iomap_iter *iter,
 		block_commit_write(&folio->page, 0, length);
 	} else {
 		WARN_ON_ONCE(!folio_test_uptodate(folio));
-		folio_mark_dirty(folio);
+
+		ifs_alloc(iter->inode, folio, 0);
+		iomap_set_range_dirty(folio, 0, length);
+		filemap_dirty_folio(iter->inode->i_mapping, folio);
 	}
 
 	return length;
-- 
2.39.2