Re: [PATCH v3 26/35] xfs: add a helper to decide if bmbt record needs offset conversion

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

On Wed, Feb 18, 2026 at 12:19:26AM +0100, Andrey Albershteyn wrote:
> A little helper for xfs_bmbt_to_iomap() to decide if offset needs to be
> converted from a large disk one to smaller page cache one.
> 
> Signed-off-by: Andrey Albershteyn <aalbersh@kernel.org>
> ---
>  fs/xfs/xfs_fsverity.c | 28 ++++++++++++++++++++++++++++
>  fs/xfs/xfs_fsverity.h |  9 +++++++++
>  2 files changed, 37 insertions(+)
> 
> diff --git a/fs/xfs/xfs_fsverity.c b/fs/xfs/xfs_fsverity.c
> index 4b918eb746d7..4f8a40317dc3 100644
> --- a/fs/xfs/xfs_fsverity.c
> +++ b/fs/xfs/xfs_fsverity.c
> @@ -5,8 +5,13 @@
>  #include "xfs.h"
>  #include "xfs_format.h"
>  #include "xfs_inode.h"
> +#include "xfs_shared.h"
> +#include "xfs_trans_resv.h"
> +#include "xfs_mount.h"
> +#include "xfs_fsverity.h"
>  #include "xfs_fsverity.h"
>  #include <linux/fsverity.h>
> +#include <linux/iomap.h>
>  
>  loff_t
>  xfs_fsverity_offset_to_disk(struct xfs_inode *ip, loff_t offset)
> @@ -33,3 +38,26 @@ xfs_fsverity_sealed_data(
>  	       (offset < fsverity_metadata_offset(inode));
>  }
>  
> +/*
> + * A little helper for xfs_bmbt_to_iomap to decide if offset needs to be
> + * converted from a large disk one to smaller page cache one.
> + *
> + * As xfs_bmbt_to_iomap() can be used during writing (tree building) and reading
> + * (fsverity enabled) we need to check for both cases.
> + */
> +bool
> +xfs_fsverity_need_convert_offset(
> +		struct xfs_inode	*ip,
> +		struct xfs_bmbt_irec	*imap,
> +		unsigned int		mapping_flags)

Odd ^^^^ indenting here.

> +{
> +	struct xfs_mount	*mp = ip->i_mount;
> +
> +	return	(fsverity_active(VFS_I(ip)) ||
> +		  xfs_iflags_test(ip, XFS_VERITY_CONSTRUCTION)) &&
> +		  (XFS_FSB_TO_B(mp, imap->br_startoff) >=
> +		  XFS_FSVERITY_REGION_START) &&

Kinda wish this wasn't a long complex if statement:

	const xfs_fileoff_t fsverity_off =
			XFS_B_TO_FSBT(mp, XFS_FSVERITY_REGION_START);

	if (!fsverity_active() && !xfs_iflags_test())
		return false;
	if (mapping_flags & IOMAP_REPORT)
		return false;
	return XFS_FSB_TO_B(mp, imap->br_startoff) >= fsverity_off;

> +		  !(mapping_flags & IOMAP_REPORT);

Hrmm.  We don't convert offsets for fiemap?  I suppose that makes sense.
IIRC the other users are bmap and swapfiles, and you can't swap to a
verity file.

(Blergh on bmap, that's just unconstrained crazy)

--D

> +
> +}
> +
> diff --git a/fs/xfs/xfs_fsverity.h b/fs/xfs/xfs_fsverity.h
> index 6f3d60f010d8..ab01ceef4d15 100644
> --- a/fs/xfs/xfs_fsverity.h
> +++ b/fs/xfs/xfs_fsverity.h
> @@ -12,6 +12,9 @@ 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);
> +bool xfs_fsverity_need_convert_offset(struct xfs_inode *ip,
> +				      struct xfs_bmbt_irec *imap,
> +				      unsigned int mapping_flags);
>  #else
>  static inline loff_t xfs_fsverity_offset_to_disk(struct xfs_inode *ip,
>  						 loff_t pos)
> @@ -30,6 +33,12 @@ static inline bool xfs_fsverity_sealed_data(const struct xfs_inode *ip,
>  {
>  	return false;
>  }
> +static inline bool xfs_fsverity_need_convert_offset(struct xfs_inode *ip,
> +						    struct xfs_bmbt_irec *imap,
> +						    unsigned int mapping_flags)
> +{
> +	return false;
> +}
>  #endif	/* CONFIG_FS_VERITY */
>  
>  #endif	/* __XFS_FSVERITY_H__ */
> -- 
> 2.51.2
> 
>