On Fri, Nov 21, 2025 at 02:08:03PM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@huawei.com>
>
> Before submitting I/O and allocating blocks with the
> EXT4_GET_BLOCKS_PRE_IO flag set, ext4_split_convert_extents() may
> convert the target extent range to initialized due to ENOSPC, ENOMEM, or
> EQUOTA errors. However, it still marks the mapping as incorrectly
> unwritten. Although this may not seem to cause any practical problems,
> it will result in an unnecessary extent conversion operation after I/O
> completion. Therefore, it's better to correct the returned mapping
> status.
>
> Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
Looks good, feel free to add:
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Regards,
ojaswin
> ---
> fs/ext4/extents.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 2db84f6b0056..19338f488550 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3916,6 +3916,8 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
>
> /* get_block() before submitting IO, split the extent */
> if (flags & EXT4_GET_BLOCKS_PRE_IO) {
> + int depth;
> +
> path = ext4_split_convert_extents(handle, inode, map, path,
> flags, allocated);
> if (IS_ERR(path))
> @@ -3931,7 +3933,13 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode,
> err = -EFSCORRUPTED;
> goto errout;
> }
> - map->m_flags |= EXT4_MAP_UNWRITTEN;
> + /* Don't mark unwritten if the extent has been zeroed out. */
> + path = ext4_find_extent(inode, map->m_lblk, path, flags);
> + if (IS_ERR(path))
> + return path;
> + depth = ext_depth(inode);
> + if (ext4_ext_is_unwritten(path[depth].p_ext))
> + map->m_flags |= EXT4_MAP_UNWRITTEN;
> goto out;
> }
> /* IO end_io complete, convert the filled extent to written */
> --
> 2.46.1
>