[PATCH 026/119] xfs: add owner field to extent allocation and freeing

[Dave Chinner]

On Thu, Jun 16, 2016 at 06:20:39PM -0700, Darrick J. Wong wrote:
> For the rmap btree to work, we have to feed the extent owner
> information to the the allocation and freeing functions. This
> information is what will end up in the rmap btree that tracks
> allocated extents. While we technically don't need the owner
> information when freeing extents, passing it allows us to validate
> that the extent we are removing from the rmap btree actually
> belonged to the owner we expected it to belong to.
....

> --- a/fs/xfs/libxfs/xfs_format.h
> +++ b/fs/xfs/libxfs/xfs_format.h
> @@ -1318,6 +1318,71 @@ typedef __be32 xfs_inobt_ptr_t;
>   */
>  #define	XFS_RMAP_CRC_MAGIC	0x524d4233	/* 'RMB3' */
>  
> +/*
> + * Ownership info for an extent.  This is used to create reverse-mapping
> + * entries.
> + */
> +#define XFS_OWNER_INFO_ATTR_FORK	(1 << 0)
> +#define XFS_OWNER_INFO_BMBT_BLOCK	(1 << 1)
> +struct xfs_owner_info {
> +	uint64_t		oi_owner;
> +	xfs_fileoff_t		oi_offset;
> +	unsigned int		oi_flags;
> +};
> +
> +static inline void
> +xfs_rmap_ag_owner(
> +	struct xfs_owner_info	*oi,
> +	uint64_t		owner)
> +{
> +	oi->oi_owner = owner;
> +	oi->oi_offset = 0;
> +	oi->oi_flags = 0;
> +}
> +
> +static inline void
> +xfs_rmap_ino_bmbt_owner(
> +	struct xfs_owner_info	*oi,
> +	xfs_ino_t		ino,
> +	int			whichfork)
> +{
> +	oi->oi_owner = ino;
> +	oi->oi_offset = 0;
> +	oi->oi_flags = XFS_OWNER_INFO_BMBT_BLOCK;
> +	if (whichfork == XFS_ATTR_FORK)
> +		oi->oi_flags |= XFS_OWNER_INFO_ATTR_FORK;
> +}
> +
> +static inline void
> +xfs_rmap_ino_owner(
> +	struct xfs_owner_info	*oi,
> +	xfs_ino_t		ino,
> +	int			whichfork,
> +	xfs_fileoff_t		offset)
> +{
> +	oi->oi_owner = ino;
> +	oi->oi_offset = offset;
> +	oi->oi_flags = 0;
> +	if (whichfork == XFS_ATTR_FORK)
> +		oi->oi_flags |= XFS_OWNER_INFO_ATTR_FORK;
> +}

One of the things we've avaoided doing so far is putting functions
like this into xfs_format.h. xfs_format.h is really just for the
on disk format definitions, not the code to access/pack/unpack it.
Hence I think think these sorts of functions need to be moved to
xfs_rmap.h....

Cheers,

Dave.

-- 
Dave Chinner
david at fromorbit.com