Re: [PATCH] ext4: mark data=journal as deprecated and will be removed in January 2028.

["Darrick J. Wong" <djwong@kernel.org>]

On Thu, Sep 24, 2026 at 10:59:24AM -0400, Theodore Ts'o wrote:
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Woooooooo
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  Documentation/admin-guide/ext4.rst | 6 ++++--
>  fs/ext4/super.c                    | 1 +
>  2 files changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst
> index ac0c709ea9e7..7aa586c27e37 100644
> --- a/Documentation/admin-guide/ext4.rst
> +++ b/Documentation/admin-guide/ext4.rst
> @@ -172,7 +172,8 @@ When mounting an ext4 filesystem, the following option are accepted:
>    data=journal
>          All data are committed into the journal prior to being written into the
>          main file system.  Enabling this mode will disable delayed allocation
> -        and O_DIRECT support.
> +        and O_DIRECT support.  This feature is deprecated and support
> +	will be removed in January 2028.
>  
>    data=ordered	(*)
>          All data are forced directly out to the main file system prior to its
> @@ -420,7 +421,8 @@ There are 3 different data modes:
>    consistent state.  This mode is the slowest except when data needs to be read
>    from and written to disk at the same time where it outperforms all others
>    modes.  Enabling this mode will disable delayed allocation and O_DIRECT
> -  support.
> +  support.  The data=journal feature is deprecated and support will be
> +  removed in January 2028.
>  
>  /proc entries
>  =============
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index a187112cafaf..8da79cc8593f 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -5049,6 +5049,7 @@ static int ext4_load_and_init_journal(struct super_block *sb,
>  static int ext4_check_journal_data_mode(struct super_block *sb)
>  {
>  	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
> +		printk(KERN_WARNING "EXT4-fs: The data=journal mount option is deprecated and support will be removed in January 2028\n");
>  		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting with "
>  			    "data=journal disables delayed allocation, "
>  			    "dioread_nolock, O_DIRECT and fast_commit support!\n");
> -- 
> 2.53.0
> 
>