Re: [PATCH v2 1/5] fsverity: strip FS_VERITY_FL from FS_IOC_SETFLAGS

[Christoph Hellwig <hch@lst.de>]

On Thu, Nov 05, 2026 at 12:55:26PM +0100, Andrey Albershteyn wrote:
> The common use of FS_IOC_GETFLAGS/SETFLAGS is get-modify-set loop.
> Filesystems could return verity status with GETFLAGS, attempting to then
> pass FS_VERITY_FL to SETFLAGS is not allowed.
> 
> The ext4 and f2fs already treat FS_VERITY_FL in the set path as no-op,
> however, BTRFS returns -EOPNOTSUPP. So, the modification of other flags
> doesn't work on BTRFS for fsverity inodes.
> 
> Fix it for BTRFS and anyone else, the ext4 and f2fs masking becomes
> no-op. The file_get/setattr() path is fine here as this flag is cleared
> right before fileattr_set_prepare(). The future fsverity support in XFS
> would also need it.
> 
> Cc: Boris Burkov <boris@bur.io>
> Cc: David Sterba <dsterba@suse.com>
> Fixes: 146054090b08 ("btrfs: initial fsverity support")
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
> ---
>  fs/file_attr.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/fs/file_attr.c b/fs/file_attr.c
> index 833e03810b24..b43977d5f8e0 100644
> --- a/fs/file_attr.c
> +++ b/fs/file_attr.c
> @@ -199,6 +199,16 @@ static int fileattr_set_prepare(struct inode *inode,
>  	if (err)
>  		return err;
>  
> +	/*
> +	 * verity is settable only via FS_IOC_ENABLE_VERITY; never through
> +	 * fileattr

Maybe spell out FS_VERITY_FL above?  Starting the sentence with a lower
case letter looks odd, and spelling out the flag name doens't hurt.

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>