Re: [PATCH 5/8] xfs: factor and move some code in xfs_log_cil.c

Alli
2022-04-29T01:57:24Z

On Wed, 2022-04-27 at 12:22 +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> In preparation for adding support for intent item whiteouts.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
Looks good to me
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>

> ---
> fs/xfs/xfs_log_cil.c | 119 ++++++++++++++++++++++++-----------------
> --
> 1 file changed, 67 insertions(+), 52 deletions(-)
>
> diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
> index e5ab62f08c19..0d8d092447ad 100644
> --- a/fs/xfs/xfs_log_cil.c
> +++ b/fs/xfs/xfs_log_cil.c
> @@ -47,6 +47,38 @@ xlog_cil_ticket_alloc(
> return tic;
> }
>
> +/*
> + * Check if the current log item was first committed in this
> sequence.
> + * We can't rely on just the log item being in the CIL, we have to
> check
> + * the recorded commit sequence number.
> + *
> + * Note: for this to be used in a non-racy manner, it has to be
> called with
> + * CIL flushing locked out. As a result, it should only be used
> during the
> + * transaction commit process when deciding what to format into the
> item.
> + */
> +static bool
> +xlog_item_in_current_chkpt(
> + struct xfs_cil *cil,
> + struct xfs_log_item *lip)
> +{
> + if (list_empty(&lip->li_cil))
> + return false;
> +
> + /*
> + * li_seq is written on the first commit of a log item to
> record the
> + * first checkpoint it is written to. Hence if it is different
> to the
> + * current sequence, we're in a new checkpoint.
> + */
> + return lip->li_seq == READ_ONCE(cil->xc_current_sequence);
> +}
> +
> +bool
> +xfs_log_item_in_current_chkpt(
> + struct xfs_log_item *lip)
> +{
> + return xlog_item_in_current_chkpt(lip->li_log->l_cilp, lip);
> +}
> +
> /*
> * Unavoidable forward declaration - xlog_cil_push_work() calls
> * xlog_cil_ctx_alloc() itself.
> @@ -934,6 +966,40 @@ xlog_cil_build_trans_hdr(
> tic->t_curr_res -= lvhdr->lv_bytes;
> }
>
> +/*
> + * Pull all the log vectors off the items in the CIL, and remove the
> items from
> + * the CIL. We don't need the CIL lock here because it's only needed
> on the
> + * transaction commit side which is currently locked out by the
> flush lock.
> + */
> +static void
> +xlog_cil_build_lv_chain(
> + struct xfs_cil *cil,
> + struct xfs_cil_ctx *ctx,
> + uint32_t *num_iovecs,
> + uint32_t *num_bytes)
> +{
> + struct xfs_log_vec *lv = NULL;
> +
> + while (!list_empty(&cil->xc_cil)) {
> + struct xfs_log_item *item;
> +
> + item = list_first_entry(&cil->xc_cil,
> + struct xfs_log_item, li_cil);
> + list_del_init(&item->li_cil);
> + if (!ctx->lv_chain)
> + ctx->lv_chain = item->li_lv;
> + else
> + lv->lv_next = item->li_lv;
> + lv = item->li_lv;
> + item->li_lv = NULL;
> + *num_iovecs += lv->lv_niovecs;
> +
> + /* we don't write ordered log vectors */
> + if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED)
> + *num_bytes += lv->lv_bytes;
> + }
> +}
> +
> /*
> * Push the Committed Item List to the log.
> *
> @@ -956,7 +1022,6 @@ xlog_cil_push_work(
> container_of(work, struct xfs_cil_ctx, push_work);
> struct xfs_cil *cil = ctx->cil;
> struct xlog *log = cil->xc_log;
> - struct xfs_log_vec *lv;
> struct xfs_cil_ctx *new_ctx;
> int num_iovecs = 0;
> int num_bytes = 0;
> @@ -1033,31 +1098,7 @@ xlog_cil_push_work(
> list_add(&ctx->committing, &cil->xc_committing);
> spin_unlock(&cil->xc_push_lock);
>
> - /*
> - * Pull all the log vectors off the items in the CIL, and
> remove the
> - * items from the CIL. We don't need the CIL lock here because
> it's only
> - * needed on the transaction commit side which is currently
> locked out
> - * by the flush lock.
> - */
> - lv = NULL;
> - while (!list_empty(&cil->xc_cil)) {
> - struct xfs_log_item *item;
> -
> - item = list_first_entry(&cil->xc_cil,
> - struct xfs_log_item, li_cil);
> - list_del_init(&item->li_cil);
> - if (!ctx->lv_chain)
> - ctx->lv_chain = item->li_lv;
> - else
> - lv->lv_next = item->li_lv;
> - lv = item->li_lv;
> - item->li_lv = NULL;
> - num_iovecs += lv->lv_niovecs;
> -
> - /* we don't write ordered log vectors */
> - if (lv->lv_buf_len != XFS_LOG_VEC_ORDERED)
> - num_bytes += lv->lv_bytes;
> - }
> + xlog_cil_build_lv_chain(cil, ctx, &num_iovecs, &num_bytes);
>
> /*
> * Switch the contexts so we can drop the context lock and move
> out
> @@ -1508,32 +1549,6 @@ xlog_cil_force_seq(
> return 0;
> }
>
> -/*
> - * Check if the current log item was first committed in this
> sequence.
> - * We can't rely on just the log item being in the CIL, we have to
> check
> - * the recorded commit sequence number.
> - *
> - * Note: for this to be used in a non-racy manner, it has to be
> called with
> - * CIL flushing locked out. As a result, it should only be used
> during the
> - * transaction commit process when deciding what to format into the
> item.
> - */
> -bool
> -xfs_log_item_in_current_chkpt(
> - struct xfs_log_item *lip)
> -{
> - struct xfs_cil *cil = lip->li_log->l_cilp;
> -
> - if (list_empty(&lip->li_cil))
> - return false;
> -
> - /*
> - * li_seq is written on the first commit of a log item to
> record the
> - * first checkpoint it is written to. Hence if it is different
> to the
> - * current sequence, we're in a new checkpoint.
> - */
> - return lip->li_seq == READ_ONCE(cil->xc_current_sequence);
> -}
> -
> /*
> * Perform initial CIL structure initialisation.
> */