Re: [RFC 6/8] ext4: Add an inode flag for atomic writes

[IBM]

Dave Chinner <david@xxxxxxxxxxxxx> writes:

> On Sat, Mar 02, 2024 at 01:12:03PM +0530, Ritesh Harjani (IBM) wrote:
>> This patch adds an inode atomic writes flag to ext4
>> (EXT4_ATOMICWRITES_FL which uses FS_ATOMICWRITES_FL flag).
>> Also add support for setting of this flag via ioctl.
>> 
>> Co-developed-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
>> Signed-off-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
>> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
>> ---
>>  fs/ext4/ext4.h  |  6 ++++++
>>  fs/ext4/ioctl.c | 11 +++++++++++
>>  2 files changed, 17 insertions(+)
>> 
>> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
>> index 1d2bce26e616..aa7fff2d6f96 100644
>> --- a/fs/ext4/ext4.h
>> +++ b/fs/ext4/ext4.h
>> @@ -495,8 +495,12 @@ struct flex_groups {
>>  #define EXT4_EA_INODE_FL	        0x00200000 /* Inode used for large EA */
>>  /* 0x00400000 was formerly EXT4_EOFBLOCKS_FL */
>>  
>> +#define EXT4_ATOMICWRITES_FL		FS_ATOMICWRITES_FL /* Inode supports atomic writes */
>>  #define EXT4_DAX_FL			0x02000000 /* Inode is DAX */
>
> Tying the on disk format to the kernel user API is a poor choice.
> While the flag bits might have the same value, anything parsing the
> on-disk format should not be required to include kernel syscall API
> header files just to get all the on-disk format definitions it
> needs.

sure. Make sense.
I will hardcode that value.

-ritesh

>
> -Dave.
> -- 
> Dave Chinner
> david@xxxxxxxxxxxxx