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

[Vivek Goyal]

On Mon, Oct 18, 2021 at 10:14:04AM -0400, Vivek Goyal wrote:
> 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?
> 

I realized that you are using FUSE_DAX_INODE to represent dax mode. So it
will be confusing to use FUSE_INODE_DAX as protocol flag. How about
FUSE_INODE_DAX_STATE instead?

Vivek

> 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
> >