Re: [PATCH v2 2/3] ext4, dax: set ext4_dax_aops for dax files

[Theodore Y. Ts'o]

On Fri, Sep 14, 2018 at 08:51:13AM -0600, Toshi Kani wrote:
> Sync syscall to DAX file needs to flush processor cache, but it
> currently does not flush to existing DAX files.  This is because
> 'ext4_da_aops' is set to address_space_operations of existing DAX
> files, instead of 'ext4_dax_aops', since S_DAX flag is set after
> ext4_set_aops() in the open path.
> 
>   New file
>   --------
>   lookup_open
>     ext4_create
>       __ext4_new_inode
>         ext4_set_inode_flags   // Set S_DAX flag
>       ext4_set_aops            // Set aops to ext4_dax_aops
> 
>   Existing file
>   -------------
>   lookup_open
>     ext4_lookup
>       ext4_iget
>         ext4_set_aops          // Set aops to ext4_da_aops
>         ext4_set_inode_flags   // Set S_DAX flag
> 
> Change ext4_iget() to initialize i_flags before ext4_set_aops().
> 
> Fixes: 5f0663bb4a64 ("ext4, dax: introduce ext4_dax_aops")
> Signed-off-by: Toshi Kani <toshi.kani@xxxxxxx>
> Suggested-by: Jan Kara <jack@xxxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
> Cc: "Theodore Ts'o" <tytso@xxxxxxx>
> Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>

Thanks, applied.

					- Ted