[Virtio-fs] [PATCH v6 3/7] fuse: support per-file DAX in fuse protocol

[Vivek Goyal]

On Mon, Oct 11, 2021 at 11:00:48AM +0800, Jeffle Xu wrote:
> Expand the fuse protocol to support per-file DAX.
> 
> FUSE_PERFILE_DAX flag is added indicating if fuse server/client

Should we call this flag FUSE_INODE_DAX instead? It is per inode property?

Vivek

> supporting per-file DAX. It can be conveyed in both FUSE_INIT request
> and reply.
> 
> FUSE_ATTR_DAX flag is added indicating if DAX shall be enabled for
> corresponding file. It is conveyed in FUSE_LOOKUP reply.
> 
> Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
> ---
>  include/uapi/linux/fuse.h | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
> index 36ed092227fa..15a1f5fc0797 100644
> --- a/include/uapi/linux/fuse.h
> +++ b/include/uapi/linux/fuse.h
> @@ -184,6 +184,9 @@
>   *
>   *  7.34
>   *  - add FUSE_SYNCFS
> + *
> + *  7.35
> + *  - add FUSE_PERFILE_DAX, FUSE_ATTR_DAX
>   */
>  
>  #ifndef _LINUX_FUSE_H
> @@ -219,7 +222,7 @@
>  #define FUSE_KERNEL_VERSION 7
>  
>  /** Minor version number of this interface */
> -#define FUSE_KERNEL_MINOR_VERSION 34
> +#define FUSE_KERNEL_MINOR_VERSION 35
>  
>  /** The node ID of the root inode */
>  #define FUSE_ROOT_ID 1
> @@ -336,6 +339,7 @@ struct fuse_file_lock {
>   *			write/truncate sgid is killed only if file has group
>   *			execute permission. (Same as Linux VFS behavior).
>   * FUSE_SETXATTR_EXT:	Server supports extended struct fuse_setxattr_in
> + * FUSE_PERFILE_DAX:	kernel supports per-file DAX
>   */
>  #define FUSE_ASYNC_READ		(1 << 0)
>  #define FUSE_POSIX_LOCKS	(1 << 1)
> @@ -367,6 +371,7 @@ struct fuse_file_lock {
>  #define FUSE_SUBMOUNTS		(1 << 27)
>  #define FUSE_HANDLE_KILLPRIV_V2	(1 << 28)
>  #define FUSE_SETXATTR_EXT	(1 << 29)
> +#define FUSE_PERFILE_DAX	(1 << 30)
>  
>  /**
>   * CUSE INIT request/reply flags
> @@ -449,8 +454,10 @@ struct fuse_file_lock {
>   * fuse_attr flags
>   *
>   * FUSE_ATTR_SUBMOUNT: Object is a submount root
> + * FUSE_ATTR_DAX: Enable DAX for this file in per-file DAX mode
>   */
>  #define FUSE_ATTR_SUBMOUNT      (1 << 0)
> +#define FUSE_ATTR_DAX		(1 << 1)
>  
>  /**
>   * Open flags
> -- 
> 2.27.0
>