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

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

[Theodore Ts'o]

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 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

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

[Darrick J. Wong]

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
> 
> 

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

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] ext4: missing device name in data=journal deprecation warning
--

commit 268d23e9918bb20498a07197e8ffc2af5574d8ca
Author: Theodore Ts'o <tytso@mit.edu>

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

This commit marks the data=journal mount option as deprecated. It updates
the admin guide documentation and adds a warning during mount indicating
that support will be removed in January 2028.

> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index bca0dc87d0b7c..d636b89090a24 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -5057,6 +5057,7 @@ 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");

[Severity: Low]
Does this code omit the filesystem device name from the log message?

Using printk() instead of the standard ext4_msg() helper means that the
superblock's device identifier (e.g., sda1) is not included in the warning.
Should this use ext4_msg(sb, KERN_WARNING, "The data=journal...") so that
administrators managing multiple ext4 filesystems can determine which
specific device is using the deprecated option?

>  		printk_once(KERN_WARNING "EXT4-fs: Warning: mounting with "
>  			    "data=journal disables delayed allocation, "
>  			    "dioread_nolock, O_DIRECT and fast_commit support!\n");

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260924145924.341425-1-tytso@mit.edu?part=1

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

[Zhang Yi]

On 9/24/2026 10:59 PM, Theodore Ts'o wrote:
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Wow, this is a significant and great decision!

Reviewed-by: Zhang Yi <yi.zhang@huawei.com>

> ---
>  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");