Re: [PATCH 09/20] xfs: factor out iclog size calculation from xlog_sync

Dave Chinner
2019-05-23T23:25:16Z

On Thu, May 23, 2019 at 07:37:31PM +0200, Christoph Hellwig wrote:
> Split out another self-contained bit of code from xlog_sync.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> fs/xfs/xfs_log.c | 64 ++++++++++++++++++++++++++++--------------------
> 1 file changed, 38 insertions(+), 26 deletions(-)
>
> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index 885470f08554..e2c9f74f86f3 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -1830,6 +1830,36 @@ xlog_split_iclog(
> return split_offset;
> }
>
> +static int
> +xlog_calc_iclog_size(
> + struct xlog *log,
> + struct xlog_in_core *iclog,
> + uint32_t *roundoff)
> +{
> + bool v2 = xfs_sb_version_haslogv2(&log->l_mp->m_sb);
> + uint32_t count_init, count;
> +
> + /* Add for LR header */
> + count_init = log->l_iclog_hsize + iclog->ic_offset;
> +
> + /* Round out the log write size */
> + if (v2 && log->l_mp->m_sb.sb_logsunit > 1) {

Hmmm, seeing as this is a now a standalone function, perhaps it
would make more sense to precalculate this whole check like so:

bool use_lsunit;

use_lsunit = xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
log->l_mp->m_sb.sb_logsunit > 1;

if (use_lsunit) {
> + /* we have a v2 stripe unit to use */
> + count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
> + } else {
> + count = BBTOB(BTOBB(count_init));
> + }

Otherwise the patch looks good.

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com