/*
 * Maps a dquot to the buffer containing its on-disk version.
 * This returns a ptr to the buffer containing the on-disk dquot
 * in the bpp param, and a ptr to the on-disk dquot within that buffer
 */
STATIC int
xfs_qm_dqtobp(
	xfs_trans_t		**tpp,
	xfs_dquot_t		*dqp,
	xfs_disk_dquot_t	**O_ddpp,
	xfs_buf_t		**O_bpp,
	uint			flags)
{
	struct xfs_bmbt_irec	map;
	int			nmaps = 1, error;
	struct xfs_buf		*bp;
	struct xfs_inode	*quotip = xfs_dq_to_quota_inode(dqp);
	struct xfs_mount	*mp = dqp->q_mount;
	xfs_dqid_t		id = be32_to_cpu(dqp->q_core.d_id);
	struct xfs_trans	*tp = (tpp ? *tpp : NULL);
	uint			lock_mode;

	dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;

	lock_mode = xfs_ilock_data_map_shared(quotip);
	if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
		/*
		 * Return if this type of quotas is turned off while we
		 * didn't have the quota inode lock.
		 */
		xfs_iunlock(quotip, lock_mode);
		return ESRCH;
	}

	/*
	 * Find the block map; no allocations yet
	 */
	error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
			       XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);

	xfs_iunlock(quotip, lock_mode);
	if (error)
		return error;

	ASSERT(nmaps == 1);
	ASSERT(map.br_blockcount == 1);

	/*
	 * Offset of dquot in the (fixed sized) dquot chunk.
	 */
	dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *
		sizeof(xfs_dqblk_t);

	ASSERT(map.br_startblock != DELAYSTARTBLOCK);
	if (map.br_startblock == HOLESTARTBLOCK) {
		/*
		 * We don't allocate unless we're asked to
		 */
		if (!(flags & XFS_QMOPT_DQALLOC))
			return ENOENT;

		ASSERT(tp);
		error = xfs_qm_dqalloc(tpp, mp, dqp, quotip,
					dqp->q_fileoffset, &bp);
		if (error)
			return error;
		tp = *tpp;
	} else {
		trace_xfs_dqtobp_read(dqp);

		/*
		 * store the blkno etc so that we don't have to do the
		 * mapping all the time
		 */
		dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);

		error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
					   dqp->q_blkno,
					   mp->m_quotainfo->qi_dqchunklen,
					   0, &bp, &xfs_dquot_buf_ops);

		if (error == EFSCORRUPTED && (flags & XFS_QMOPT_DQREPAIR)) {
			xfs_dqid_t firstid = (xfs_dqid_t)map.br_startoff *
						mp->m_quotainfo->qi_dqperchunk;
			ASSERT(bp == NULL);
			error = xfs_qm_dqrepair(mp, tp, dqp, firstid, &bp);
		}

		if (error) {
			ASSERT(bp == NULL);
			return XFS_ERROR(error);
		}
	}

	ASSERT(xfs_buf_islocked(bp));
	*O_bpp = bp;
	*O_ddpp = bp->b_addr + dqp->q_bufoffset;

	return (0);
}
/*
 * Maps a dquot to the buffer containing its on-disk version.
 * This returns a ptr to the buffer containing the on-disk dquot
 * in the bpp param, and a ptr to the on-disk dquot within that buffer
 */
STATIC int
xfs_qm_dqtobp(
	xfs_trans_t		**tpp,
	xfs_dquot_t		*dqp,
	xfs_disk_dquot_t	**O_ddpp,
	xfs_buf_t		**O_bpp,
	uint			flags)
{
	xfs_bmbt_irec_t map;
	int		nmaps = 1, error;
	xfs_buf_t	*bp;
	xfs_inode_t	*quotip = XFS_DQ_TO_QIP(dqp);
	xfs_mount_t	*mp = dqp->q_mount;
	xfs_disk_dquot_t *ddq;
	xfs_dqid_t	id = be32_to_cpu(dqp->q_core.d_id);
	xfs_trans_t	*tp = (tpp ? *tpp : NULL);

	dqp->q_fileoffset = (xfs_fileoff_t)id / mp->m_quotainfo->qi_dqperchunk;

	xfs_ilock(quotip, XFS_ILOCK_SHARED);
	if (!xfs_this_quota_on(dqp->q_mount, dqp->dq_flags)) {
		/*
		 * Return if this type of quotas is turned off while we
		 * didn't have the quota inode lock.
		 */
		xfs_iunlock(quotip, XFS_ILOCK_SHARED);
		return ESRCH;
	}

	/*
	 * Find the block map; no allocations yet
	 */
	error = xfs_bmapi_read(quotip, dqp->q_fileoffset,
			       XFS_DQUOT_CLUSTER_SIZE_FSB, &map, &nmaps, 0);

	xfs_iunlock(quotip, XFS_ILOCK_SHARED);
	if (error)
		return error;

	ASSERT(nmaps == 1);
	ASSERT(map.br_blockcount == 1);

	/*
	 * Offset of dquot in the (fixed sized) dquot chunk.
	 */
	dqp->q_bufoffset = (id % mp->m_quotainfo->qi_dqperchunk) *
		sizeof(xfs_dqblk_t);

	ASSERT(map.br_startblock != DELAYSTARTBLOCK);
	if (map.br_startblock == HOLESTARTBLOCK) {
		/*
		 * We don't allocate unless we're asked to
		 */
		if (!(flags & XFS_QMOPT_DQALLOC))
			return ENOENT;

		ASSERT(tp);
		error = xfs_qm_dqalloc(tpp, mp, dqp, quotip,
					dqp->q_fileoffset, &bp);
		if (error)
			return error;
		tp = *tpp;
	} else {
		trace_xfs_dqtobp_read(dqp);

		/*
		 * store the blkno etc so that we don't have to do the
		 * mapping all the time
		 */
		dqp->q_blkno = XFS_FSB_TO_DADDR(mp, map.br_startblock);

		error = xfs_trans_read_buf(mp, tp, mp->m_ddev_targp,
					   dqp->q_blkno,
					   mp->m_quotainfo->qi_dqchunklen,
					   0, &bp);
		if (error || !bp)
			return XFS_ERROR(error);
	}

	ASSERT(xfs_buf_islocked(bp));

	/*
	 * calculate the location of the dquot inside the buffer.
	 */
	ddq = bp->b_addr + dqp->q_bufoffset;

	/*
	 * A simple sanity check in case we got a corrupted dquot...
	 */
	error = xfs_qm_dqcheck(mp, ddq, id, dqp->dq_flags & XFS_DQ_ALLTYPES,
			   flags & (XFS_QMOPT_DQREPAIR|XFS_QMOPT_DOWARN),
			   "dqtobp");
	if (error) {
		if (!(flags & XFS_QMOPT_DQREPAIR)) {
			xfs_trans_brelse(tp, bp);
			return XFS_ERROR(EIO);
		}
	}

	*O_bpp = bp;
	*O_ddpp = ddq;

	return (0);
}