Re: [PATCH v2] ext4: don't order data when zeroing unwritten or delayed block

[Theodore Ts'o]

On Tue, 23 Dec 2025 09:19:27 +0800, Zhang Yi wrote:
> When zeroing out a written partial block, it is necessary to order the
> data to prevent exposing stale data on disk. However, if the buffer is
> unwritten or delayed, it is not allocated as written, so ordering the
> data is not required. This can prevent strange and unnecessary ordered
> writes when appending data across a region within a block.
> 
> Assume we have a 2K unwritten file on a filesystem with 4K blocksize,
> and buffered write from 3K to 4K. Before this patch,
> __ext4_block_zero_page_range() would add the range [2k,3k) to the
> ordered range, and then the JBD2 commit process would write back this
> block. However, it does nothing since the block is not mapped as
> written, this folio will be redirtied and written back agian through the
> normal write back process.
> 
> [...]

Applied, thanks!

[1/1] ext4: don't order data when zeroing unwritten or delayed block
      commit: 154922b34da9770223d9883ac6976635a786b5ba

Best regards,
-- 
Theodore Ts'o <tytso@xxxxxxx>