ext4: remove page offset calculation in ext4_block_truncate_page()

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@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Message-ID: <20251121090654.631996-3-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 4afe227fd03f8f92947e030ef08166e3feb82c12..d232154cc14d561f97cd0aea322ce9886f5376a9 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4193,7 +4193,6 @@ 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;
@@ -4202,8 +4201,8 @@ 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);
 }