linux-ext4 - Re: [PATCH 3/5] fuse: implement file attributes mask for statx

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Message-ID: <CAJnrk1ZgQy7osiYfb6_Ra=a4-G4nxiiFJZgNLLZYnGtL=a7QBg@mail.gmail.com>
Date: Mon, 3 Nov 2025 10:30:59 -0800
From: Joanne Koong <joannelkoong@...il.com>
To: "Darrick J. Wong" <djwong@...nel.org>
Cc: miklos@...redi.hu, bernd@...ernd.com, neal@...pa.dev, 
	linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 3/5] fuse: implement file attributes mask for statx

> diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
> index a8068bee90af57..8c47d103c8ffa6 100644
> --- a/fs/fuse/fuse_i.h
> +++ b/fs/fuse/fuse_i.h
> @@ -140,6 +140,10 @@ struct fuse_inode {
>         /** Version of last attribute change */
>         u64 attr_version;
>
> +       /** statx file attributes */
> +       u64 statx_attributes;
> +       u64 statx_attributes_mask;
> +
>         union {
>                 /* read/write io cache (regular file only) */
>                 struct {
> @@ -1235,6 +1239,39 @@ void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
>                                    u64 attr_valid, u32 cache_mask,
>                                    u64 evict_ctr);
>
> +/*
> + * These statx attribute flags are set by the VFS so mask them out of replies
> + * from the fuse server for local filesystems.  Nonlocal filesystems are
> + * responsible for enforcing and advertising these flags themselves.
> + */
> +#define FUSE_STATX_LOCAL_VFS_ATTRIBUTES (STATX_ATTR_IMMUTABLE | \
> +                                        STATX_ATTR_APPEND)

for STATX_ATTR_IMMUTABLE and STATX_ATTR_APPEND, I see in
generic_fill_statx_attr() that they get set if the inode has the
S_IMMUTABLE flag and the S_APPEND flag set, but I'm not seeing how
this is relevant to fuse. I'm not seeing anywhere in the vfs layer
that sets S_APPEND or STATX_ATTR_IMMUTABLE, I only see specific
filesystems setting them, which fuse doesn't do. Is there something
I'm missing?

Thanks,
Joanne