On Sun, Apr 20, 2025 at 6:34 PM John Groves <j...@groves.net> wrote:
>
> * FUSE_DAX_FMAP flag in INIT request/reply
>
> * fuse_conn->famfs_iomap (enable famfs-mapped files) to denote a
> famfs-enabled connection
>
> Signed-off-by: John Groves <j...@groves.net>
> ---
> fs/fuse/fuse_i.h | 3 +++
> fs/fuse/inode.c | 5 +++++
> include/uapi/linux/fuse.h | 2 ++
> 3 files changed, 10 insertions(+)
>
> diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
> index e04d160fa995..b2c563b1a1c8 100644
> --- a/fs/fuse/fuse_i.h
> +++ b/fs/fuse/fuse_i.h
> @@ -870,6 +870,9 @@ struct fuse_conn {
> /* Use io_uring for communication */
> unsigned int io_uring;
>
> + /* dev_dax_iomap support for famfs */
> + unsigned int famfs_iomap:1;
> +
> /** Maximum stack depth for passthrough backing files */
> int max_stack_depth;
>
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index 29147657a99f..5c6947b12503 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -1392,6 +1392,9 @@ static void process_init_reply(struct fuse_mount *fm,
> struct fuse_args *args,
> }
> if (flags & FUSE_OVER_IO_URING &&
> fuse_uring_enabled())
> fc->io_uring = 1;
> + if (IS_ENABLED(CONFIG_FUSE_FAMFS_DAX) &&
> + flags & FUSE_DAX_FMAP)
> + fc->famfs_iomap = 1;
> } else {
> ra_pages = fc->max_read / PAGE_SIZE;
> fc->no_lock = 1;
> @@ -1450,6 +1453,8 @@ void fuse_send_init(struct fuse_mount *fm)
> flags |= FUSE_SUBMOUNTS;
> if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
> flags |= FUSE_PASSTHROUGH;
> + if (IS_ENABLED(CONFIG_FUSE_FAMFS_DAX))
> + flags |= FUSE_DAX_FMAP;
>
> /*
> * This is just an information flag for fuse server. No need to check
> diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
> index 5e0eb41d967e..f9e14180367a 100644
> --- a/include/uapi/linux/fuse.h
> +++ b/include/uapi/linux/fuse.h
> @@ -435,6 +435,7 @@ struct fuse_file_lock {
> * of the request ID indicates resend requests
> * FUSE_ALLOW_IDMAP: allow creation of idmapped mounts
> * FUSE_OVER_IO_URING: Indicate that client supports io-uring
> + * FUSE_DAX_FMAP: kernel supports dev_dax_iomap (aka famfs) fmaps
> */
> #define FUSE_ASYNC_READ (1 << 0)
> #define FUSE_POSIX_LOCKS (1 << 1)
> @@ -482,6 +483,7 @@ struct fuse_file_lock {
> #define FUSE_DIRECT_IO_RELAX FUSE_DIRECT_IO_ALLOW_MMAP
> #define FUSE_ALLOW_IDMAP (1ULL << 40)
> #define FUSE_OVER_IO_URING (1ULL << 41)
> +#define FUSE_DAX_FMAP (1ULL << 42)
There's also a protocol changelog at the top of this file that tracks
any updates made to the uapi. We should probably also update that to
include this?
Thanks,
Joanne
>
> /**
> * CUSE INIT request/reply flags
> --
> 2.49.0
>
