linux-kernel - [PATCH 16/27] ext4: don't order data for inode with EXT4_STATE_BUFFERED

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Message-ID: <20241022111059.2566137-17-yi.zhang@huaweicloud.com>
Date: Tue, 22 Oct 2024 19:10:47 +0800
From: Zhang Yi <yi.zhang@...weicloud.com>
To: linux-ext4@...r.kernel.org
Cc: linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	tytso@....edu,
	adilger.kernel@...ger.ca,
	jack@...e.cz,
	ritesh.list@...il.com,
	hch@...radead.org,
	djwong@...nel.org,
	david@...morbit.com,
	zokeefe@...gle.com,
	yi.zhang@...wei.com,
	yi.zhang@...weicloud.com,
	chengzhihao1@...wei.com,
	yukuai3@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH 16/27] ext4: don't order data for inode with EXT4_STATE_BUFFERED_IOMAP

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

In the iomap buffered I/O path, there is no risk of exposing stale data
because we always allocate unwritten extents for new allocated blocks,
the extent changes to written only when the I/O is completed. Therefore,
we do not need to order data in this mode.

Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/ext4/ext4_jbd2.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 0c77697d5e90..9dca10027032 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -467,6 +467,14 @@ static inline int ext4_should_journal_data(struct inode *inode)
 
 static inline int ext4_should_order_data(struct inode *inode)
 {
+	/*
+	 * There is no need to order data for inodes with iomap buffered I/O
+	 * path since it always allocate unwritten extents for new allocated
+	 * blocks and have no risk of stale data.
+	 */
+	if (ext4_test_inode_state(inode, EXT4_STATE_BUFFERED_IOMAP))
+		return 0;
+
 	return ext4_inode_journal_mode(inode) & EXT4_INODE_ORDERED_DATA_MODE;
 }
 
-- 
2.46.1