Re: [PATCH 05/24] xfs: define the on-disk refcount btree format

[Dave Chinner <david@fromorbit.com>]

On Wed, Jul 29, 2015 at 03:33:30PM -0700, Darrick J. Wong wrote:
> Start constructing the refcount btree implementation by establishing
> the on-disk format and everything needed to read, write, and
> manipulate the refcount btree blocks.
> 
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
....
> +STATIC bool
> +xfs_refcountbt_verify(
> +	struct xfs_buf		*bp)

feel free to shorten that prefix to xfs_refcbt_.....

> +{
> +	struct xfs_mount	*mp = bp->b_target->bt_mount;
> +	struct xfs_btree_block	*block = XFS_BUF_TO_BLOCK(bp);
> +	struct xfs_perag	*pag = bp->b_pag;
> +	unsigned int		level;
> +
> +	if (block->bb_magic != cpu_to_be32(XFS_REFC_CRC_MAGIC))
> +		return false;
> +
> +	if (!xfs_sb_version_hasreflink(&mp->m_sb))
> +		return false;
> +	if (!uuid_equal(&block->bb_u.s.bb_uuid, &mp->m_sb.sb_uuid))
> +		return false;
> +	if (block->bb_u.s.bb_blkno != cpu_to_be64(bp->b_bn))
> +		return false;
> +	if (pag &&
> +	    be32_to_cpu(block->bb_u.s.bb_owner) != pag->pag_agno)
> +		return false;
> +
> +	level = be16_to_cpu(block->bb_level);
> +	if (pag && pag->pagf_init) {
> +		if (level >= pag->pagf_refcount_level)
> +			return false;
> +	} else if (level >= mp->m_ag_maxlevels)
> +		return false;
> +
> +	/* numrecs verification */
> +	if (be16_to_cpu(block->bb_numrecs) > mp->m_refc_mxr[level != 0])
> +		return false;
> +
> +	/* sibling pointer verification */
> +	if (!block->bb_u.s.bb_leftsib ||
> +	    (be32_to_cpu(block->bb_u.s.bb_leftsib) >= mp->m_sb.sb_agblocks &&
> +	     block->bb_u.s.bb_leftsib != cpu_to_be32(NULLAGBLOCK)))
> +		return false;
> +	if (!block->bb_u.s.bb_rightsib ||
> +	    (be32_to_cpu(block->bb_u.s.bb_rightsib) >= mp->m_sb.sb_agblocks &&
> +	     block->bb_u.s.bb_rightsib != cpu_to_be32(NULLAGBLOCK)))
> +		return false;

I'm starting to think there's a xfs_btree_sblock_verify() function
we need to factor out of all these btree verification functions...

> +#ifndef __XFS_REFCOUNT_BTREE_H__
> +#define	__XFS_REFCOUNT_BTREE_H__
> +
> +/*
> + * Freespace on-disk structures
> + */
> +
> +struct xfs_buf;
> +struct xfs_btree_cur;
> +struct xfs_mount;
> +
> +/*
> + * Btree block header size depends on a superblock flag.
> + */
> +#define XFS_REFCOUNT_BLOCK_LEN	XFS_BTREE_SBLOCK_CRC_LEN

Comment is stale.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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