Re: [PATCH v4 0/6] Add alignment check for DAX mount

[Carlos Maiolino]

On Tue, May 10, 2016 at 10:23:51AM -0600, Toshi Kani wrote:
> When a partition is not aligned by 4KB, mount -o dax succeeds,
> but any read/write access to the filesystem fails, except for
> metadata update.  Add alignment check to ext4, ext2, and xfs.
> 
> - Patch 1-2 add bdev_dax_supported() which performs all the checks
>   necessary for dax mount.
> - Patch 3-5 change fillesystems to call bdev_dax_supported().
> - Patch 6 is a cleanup to keep dax capability checks consistent.
> 
> v4:
>  - blkdev_dax_capable() is similar to bdev_dax_supported().
>    Manage them consistently. (Dan Williams, Dave Chinner)
> 
> v3:
>  - Remove boilerplate code from filesytems (Christoph Hellwig)
>  - Add a helper function to perform all checks (Dave Chinner)
> 
> v2:
>  - Use a helper function via ->direct_access for the check.
>    (Christoph Hellwig)
>  - Call bdev_direct_access() with sector 0 for the check.
>    (Boaz Harrosh)
> 
> ---
> Toshi Kani (6):
>  1/6 block: Add vfs_msg() interface
>  2/6 block: Add bdev_dax_supported() for dax mount checks
>  3/6 ext4: Add alignment check for DAX mount
>  4/6 ext2: Add alignment check for DAX mount
>  5/6 xfs: Add alignment check for DAX mount
>  6/6 block: Update blkdev_dax_capable() for consistency
> 

Despite Jan's comment on patch 6, that I should agree, that checking DAX during
compile time is better than at run time, all patches looks good to me, the
conflicts with Dan's patches, also should not cause any semantics change of this
patchset, you can add:

Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>


Cheers
> ---
>  block/ioctl.c          | 30 ----------------
>  fs/block_dev.c         | 96 ++++++++++++++++++++++++++++++++++++++++++++++++--
>  fs/ext2/super.c        | 11 ++----
>  fs/ext4/super.c        | 11 ++----
>  fs/xfs/xfs_super.c     | 12 +++----
>  include/linux/blkdev.h | 13 +++++++
>  include/linux/fs.h     |  8 -----
>  7 files changed, 116 insertions(+), 65 deletions(-)
> --
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-- 
Carlos