linux-kernel - [PATCH 02/25] ext4: remove page offset calculation in ext4_block_truncate

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Message-Id: <20251025032221.2905818-3-libaokun@huaweicloud.com>
Date: Sat, 25 Oct 2025 11:21:58 +0800
From: libaokun@...weicloud.com
To: linux-ext4@...r.kernel.org
Cc: tytso@....edu,
	adilger.kernel@...ger.ca,
	jack@...e.cz,
	linux-kernel@...r.kernel.org,
	kernel@...kajraghav.com,
	mcgrof@...nel.org,
	linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org,
	yi.zhang@...wei.com,
	yangerkun@...wei.com,
	chengzhihao1@...wei.com,
	libaokun1@...wei.com,
	libaokun@...weicloud.com
Subject: [PATCH 02/25] ext4: remove page offset calculation in ext4_block_truncate_page()

From: Baokun Li <libaokun1@...wei.com>

For bs <= ps scenarios, calculating the offset within the block is
sufficient. For bs > ps, an initial page offset calculation can lead to
incorrect behavior. Thus this redundant calculation has been removed.

Signed-off-by: Baokun Li <libaokun1@...wei.com>
Reviewed-by: Zhang Yi <yi.zhang@...wei.com>
---
 fs/ext4/inode.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0742039c53a7..4c04af7e51c9 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4183,7 +4183,6 @@ static int ext4_block_zero_page_range(handle_t *handle,
 static int ext4_block_truncate_page(handle_t *handle,
 		struct address_space *mapping, loff_t from)
 {
-	unsigned offset = from & (PAGE_SIZE-1);
 	unsigned length;
 	unsigned blocksize;
 	struct inode *inode = mapping->host;
@@ -4192,8 +4191,8 @@ static int ext4_block_truncate_page(handle_t *handle,
 	if (IS_ENCRYPTED(inode) && !fscrypt_has_encryption_key(inode))
 		return 0;
 
-	blocksize = inode->i_sb->s_blocksize;
-	length = blocksize - (offset & (blocksize - 1));
+	blocksize = i_blocksize(inode);
+	length = blocksize - (from & (blocksize - 1));
 
 	return ext4_block_zero_page_range(handle, mapping, from, length);
 }
-- 
2.46.1