Re: [PATCH v3 25/35] xfs: add helpers to convert between pagecache and on-disk offset

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Feb 18, 2026 at 12:19:25AM +0100, Andrey Albershteyn wrote:
> This helpers converts offset which XFS uses to store fsverity metadata
> on disk to the offset in the pagecache.
> 
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
> ---
>  fs/xfs/xfs_fsverity.c | 14 ++++++++++++++
>  fs/xfs/xfs_fsverity.h | 13 +++++++++++++
>  2 files changed, 27 insertions(+)
> 
> diff --git a/fs/xfs/xfs_fsverity.c b/fs/xfs/xfs_fsverity.c
> index 47add19a241e..4b918eb746d7 100644
> --- a/fs/xfs/xfs_fsverity.c
> +++ b/fs/xfs/xfs_fsverity.c
> @@ -8,6 +8,20 @@
>  #include "xfs_fsverity.h"
>  #include <linux/fsverity.h>
>  
> +loff_t
> +xfs_fsverity_offset_to_disk(struct xfs_inode *ip, loff_t offset)
> +{
> +	return (offset - fsverity_metadata_offset(VFS_I(ip))) |
> +	       XFS_FSVERITY_REGION_START;
> +}
> +
> +loff_t
> +xfs_fsverity_offset_from_disk(struct xfs_inode *ip, loff_t offset)

The type signatures here confused me.  The @offset parameter to
_from_disk is the ondisk file offset of fsverity metadata?  And we
return the ...  incore file offset of the fsverity metadata?

It's harder to be helpful when reviewing patches that add helpers
without actually using them.

I don't know if I should suggest that the input parameter should be a
different type altogether (xfs_fileoff_t?) because I can't see here how
the helper is used.

> +{
> +	return (offset ^ XFS_FSVERITY_REGION_START) +
> +	       fsverity_metadata_offset(VFS_I(ip));

This logic is a little obscure here; is this really just:

	offset - XFS_FSVERITY_REGION_START + fsverity_metadata_offset()
?

--D

> +}
> +
>  bool
>  xfs_fsverity_sealed_data(
>  	const struct xfs_inode	*ip,
> diff --git a/fs/xfs/xfs_fsverity.h b/fs/xfs/xfs_fsverity.h
> index 5fc55f42b317..6f3d60f010d8 100644
> --- a/fs/xfs/xfs_fsverity.h
> +++ b/fs/xfs/xfs_fsverity.h
> @@ -10,6 +10,8 @@
>  #ifdef CONFIG_FS_VERITY
>  bool xfs_fsverity_sealed_data(const struct xfs_inode *ip,
>  		loff_t offset);
> +loff_t xfs_fsverity_offset_to_disk(struct xfs_inode *ip, loff_t pos);
> +loff_t xfs_fsverity_offset_from_disk(struct xfs_inode *ip, loff_t offset);
>  #else
>  static inline loff_t xfs_fsverity_offset_to_disk(struct xfs_inode *ip,
>  						 loff_t pos)
> @@ -17,6 +19,17 @@ static inline loff_t xfs_fsverity_offset_to_disk(struct xfs_inode *ip,
>  	WARN_ON_ONCE(1);
>  	return ULLONG_MAX;
>  }
> +static inline loff_t xfs_fsverity_offset_from_disk(struct xfs_inode *ip,
> +						   loff_t offset)
> +{
> +	WARN_ON_ONCE(1);
> +	return ULLONG_MAX;
> +}
> +static inline bool xfs_fsverity_sealed_data(const struct xfs_inode *ip,
> +					    loff_t offset)
> +{
> +	return false;
> +}
>  #endif	/* CONFIG_FS_VERITY */
>  
>  #endif	/* __XFS_FSVERITY_H__ */
> -- 
> 2.51.2
> 
>