Re: [RFC V2 09/18] famfs_fuse: Update macro s/FUSE_IS_DAX/FUSE_IS_VIRTIO_DAX/

[Amir Goldstein <amir73il@gmail.com>]

On Thu, Jul 3, 2025 at 8:51 PM John Groves <John@groves.net> wrote:
>
> Virtio_fs now needs to determine if an inode is DAX && not famfs.
>
> Signed-off-by: John Groves <john@groves.net>
> ---
>  fs/fuse/dir.c    |  2 +-
>  fs/fuse/file.c   | 13 ++++++++-----
>  fs/fuse/fuse_i.h |  6 +++++-
>  fs/fuse/inode.c  |  2 +-
>  fs/fuse/iomode.c |  2 +-
>  5 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
> index 8f699c67561f..ad8cdf7b864a 100644
> --- a/fs/fuse/dir.c
> +++ b/fs/fuse/dir.c
> @@ -1939,7 +1939,7 @@ int fuse_do_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
>                 is_truncate = true;
>         }
>
> -       if (FUSE_IS_DAX(inode) && is_truncate) {
> +       if (FUSE_IS_VIRTIO_DAX(fi) && is_truncate) {
>                 filemap_invalidate_lock(mapping);
>                 fault_blocked = true;
>                 err = fuse_dax_break_layouts(inode, 0, -1);
> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
> index 754378dd9f71..93b82660f0c8 100644
> --- a/fs/fuse/file.c
> +++ b/fs/fuse/file.c
> @@ -239,7 +239,7 @@ static int fuse_open(struct inode *inode, struct file *file)
>         int err;
>         bool is_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc;
>         bool is_wb_truncate = is_truncate && fc->writeback_cache;
> -       bool dax_truncate = is_truncate && FUSE_IS_DAX(inode);
> +       bool dax_truncate = is_truncate && FUSE_IS_VIRTIO_DAX(fi);
>
>         if (fuse_is_bad(inode))
>                 return -EIO;
> @@ -1770,11 +1770,12 @@ static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
>         struct file *file = iocb->ki_filp;
>         struct fuse_file *ff = file->private_data;
>         struct inode *inode = file_inode(file);
> +       struct fuse_inode *fi = get_fuse_inode(inode);
>
>         if (fuse_is_bad(inode))
>                 return -EIO;
>
> -       if (FUSE_IS_DAX(inode))
> +       if (FUSE_IS_VIRTIO_DAX(fi))
>                 return fuse_dax_read_iter(iocb, to);
>
>         /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
> @@ -1791,11 +1792,12 @@ static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>         struct file *file = iocb->ki_filp;
>         struct fuse_file *ff = file->private_data;
>         struct inode *inode = file_inode(file);
> +       struct fuse_inode *fi = get_fuse_inode(inode);
>
>         if (fuse_is_bad(inode))
>                 return -EIO;
>
> -       if (FUSE_IS_DAX(inode))
> +       if (FUSE_IS_VIRTIO_DAX(fi))
>                 return fuse_dax_write_iter(iocb, from);
>
>         /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */
> @@ -2627,10 +2629,11 @@ static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
>         struct fuse_file *ff = file->private_data;
>         struct fuse_conn *fc = ff->fm->fc;
>         struct inode *inode = file_inode(file);
> +       struct fuse_inode *fi = get_fuse_inode(inode);
>         int rc;
>
>         /* DAX mmap is superior to direct_io mmap */
> -       if (FUSE_IS_DAX(inode))
> +       if (FUSE_IS_VIRTIO_DAX(fi))
>                 return fuse_dax_mmap(file, vma);
>
>         /*
> @@ -3191,7 +3194,7 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
>                 .mode = mode
>         };
>         int err;
> -       bool block_faults = FUSE_IS_DAX(inode) &&
> +       bool block_faults = FUSE_IS_VIRTIO_DAX(fi) &&
>                 (!(mode & FALLOC_FL_KEEP_SIZE) ||
>                  (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)));
>
> diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
> index 2086dac7243b..9d87ac48d724 100644
> --- a/fs/fuse/fuse_i.h
> +++ b/fs/fuse/fuse_i.h
> @@ -1426,7 +1426,11 @@ void fuse_free_conn(struct fuse_conn *fc);
>
>  /* dax.c */
>
> -#define FUSE_IS_DAX(inode) (IS_ENABLED(CONFIG_FUSE_DAX) && IS_DAX(inode))
> +/* This macro is used by virtio_fs, but now it also needs to filter for
> + * "not famfs"
> + */
> +#define FUSE_IS_VIRTIO_DAX(fuse_inode) (IS_ENABLED(CONFIG_FUSE_DAX)    \
> +                                       && IS_DAX(&fuse_inode->inode))

I think we should take this opportunity to make it
static inline fuse_is_virtio_dax()

and because some of the call site really do want to know if this is dax
should also leave a helper

static inline fuse_is_dax()

...

>
>  ssize_t fuse_dax_read_iter(struct kiocb *iocb, struct iov_iter *to);
>  ssize_t fuse_dax_write_iter(struct kiocb *iocb, struct iov_iter *from);
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index e9db2cb8c150..29147657a99f 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -164,7 +164,7 @@ static void fuse_evict_inode(struct inode *inode)
>         if (inode->i_sb->s_flags & SB_ACTIVE) {
>                 struct fuse_conn *fc = get_fuse_conn(inode);
>
> -               if (FUSE_IS_DAX(inode))
> +               if (FUSE_IS_VIRTIO_DAX(fi))
>                         fuse_dax_inode_cleanup(inode);
>                 if (fi->nlookup) {
>                         fuse_queue_forget(fc, fi->forget, fi->nodeid,
> diff --git a/fs/fuse/iomode.c b/fs/fuse/iomode.c
> index c99e285f3183..aec4aecb5d79 100644
> --- a/fs/fuse/iomode.c
> +++ b/fs/fuse/iomode.c
> @@ -204,7 +204,7 @@ int fuse_file_io_open(struct file *file, struct inode *inode)
>          * io modes are not relevant with DAX and with server that does not
>          * implement open.
>          */
> -       if (FUSE_IS_DAX(inode) || !ff->args)
> +       if (FUSE_IS_VIRTIO_DAX(fi) || !ff->args)
>                 return 0;
>

... Like here, later in your patch set you add explicit check for
!fuse_famfs_file()

If you make this into if (fuse_is_dax(fi)
it will be easier and nicer in the end.

Thanks,
Amir.