[PATCH 19/45] xfs: factor out the CIL transaction header building

Dave Chinner
2021-03-05T05:12:55Z

From: Dave Chinner <dchinner@redhat.com>

It is static code deep in the middle of the CIL push logic. Factor
it out into a helper so that it is clear and easy to modify
separately.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_log_cil.c | 71 +++++++++++++++++++++++++++++---------------
1 file changed, 47 insertions(+), 24 deletions(-)

diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c
index dfc9ef692a80..b515002e7959 100644
--- a/fs/xfs/xfs_log_cil.c
+++ b/fs/xfs/xfs_log_cil.c
@@ -651,6 +651,41 @@ xlog_cil_process_committed(
}
}

+struct xlog_cil_trans_hdr {
+ struct xfs_trans_header thdr;
+ struct xfs_log_iovec lhdr;
+};
+
+/*
+ * Build a checkpoint transaction header to begin the journal transaction. We
+ * need to account for the space used by the transaction header here as it is
+ * not accounted for in xlog_write().
+ */
+static void
+xlog_cil_build_trans_hdr(
+ struct xfs_cil_ctx *ctx,
+ struct xlog_cil_trans_hdr *hdr,
+ struct xfs_log_vec *lvhdr,
+ int num_iovecs)
+{
+ struct xlog_ticket *tic = ctx->ticket;
+
+ memset(hdr, 0, sizeof(*hdr));
+
+ hdr->thdr.th_magic = XFS_TRANS_HEADER_MAGIC;
+ hdr->thdr.th_type = XFS_TRANS_CHECKPOINT;
+ hdr->thdr.th_tid = tic->t_tid;
+ hdr->thdr.th_num_items = num_iovecs;
+ hdr->lhdr.i_addr = &hdr->thdr;
+ hdr->lhdr.i_len = sizeof(xfs_trans_header_t);
+ hdr->lhdr.i_type = XLOG_REG_TYPE_TRANSHDR;
+ tic->t_curr_res -= hdr->lhdr.i_len + sizeof(xlog_op_header_t);
+
+ lvhdr->lv_niovecs = 1;
+ lvhdr->lv_iovecp = &hdr->lhdr;
+ lvhdr->lv_next = ctx->lv_chain;
+}
+
/*
* Push the Committed Item List to the log.
*
@@ -676,11 +711,9 @@ xlog_cil_push_work(
struct xfs_log_vec *lv;
struct xfs_cil_ctx *new_ctx;
struct xlog_in_core *commit_iclog;
- struct xlog_ticket *tic;
int num_iovecs;
int error = 0;
- struct xfs_trans_header thdr;
- struct xfs_log_iovec lhdr;
+ struct xlog_cil_trans_hdr thdr;
struct xfs_log_vec lvhdr = { NULL };
xfs_lsn_t commit_lsn;
xfs_lsn_t push_seq;
@@ -827,24 +860,8 @@ xlog_cil_push_work(
* Build a checkpoint transaction header and write it to the log to
* begin the transaction. We need to account for the space used by the
* transaction header here as it is not accounted for in xlog_write().
- *
- * The LSN we need to pass to the log items on transaction commit is
- * the LSN reported by the first log vector write. If we use the commit
- * record lsn then we can move the tail beyond the grant write head.
*/
- tic = ctx->ticket;
- thdr.th_magic = XFS_TRANS_HEADER_MAGIC;
- thdr.th_type = XFS_TRANS_CHECKPOINT;
- thdr.th_tid = tic->t_tid;
- thdr.th_num_items = num_iovecs;
- lhdr.i_addr = &thdr;
- lhdr.i_len = sizeof(xfs_trans_header_t);
- lhdr.i_type = XLOG_REG_TYPE_TRANSHDR;
- tic->t_curr_res -= lhdr.i_len + sizeof(xlog_op_header_t);
-
- lvhdr.lv_niovecs = 1;
- lvhdr.lv_iovecp = &lhdr;
- lvhdr.lv_next = ctx->lv_chain;
+ xlog_cil_build_trans_hdr(ctx, &thdr, &lvhdr, num_iovecs);

/*
* Before we format and submit the first iclog, we have to ensure that
@@ -852,7 +869,13 @@ xlog_cil_push_work(
*/
wait_for_completion(&bdev_flush);

- error = xlog_write(log, &lvhdr, tic, &ctx->start_lsn, NULL,
+ /*
+ * The LSN we need to pass to the log items on transaction commit is the
+ * LSN reported by the first log vector write, not the commit lsn. If we
+ * use the commit record lsn then we can move the tail beyond the grant
+ * write head.
+ */
+ error = xlog_write(log, &lvhdr, ctx->ticket, &ctx->start_lsn, NULL,
XLOG_START_TRANS);
if (error)
goto out_abort_free_ticket;
@@ -891,11 +914,11 @@ xlog_cil_push_work(
}
spin_unlock(&cil->xc_push_lock);

- error = xlog_commit_record(log, tic, &commit_iclog, &commit_lsn);
+ error = xlog_commit_record(log, ctx->ticket, &commit_iclog, &commit_lsn);
if (error)
goto out_abort_free_ticket;

- xfs_log_ticket_ungrant(log, tic);
+ xfs_log_ticket_ungrant(log, ctx->ticket);

spin_lock(&commit_iclog->ic_callback_lock);
if (commit_iclog->ic_state == XLOG_STATE_IOERROR) {
@@ -946,7 +969,7 @@ xlog_cil_push_work(
return;

out_abort_free_ticket:
- xfs_log_ticket_ungrant(log, tic);
+ xfs_log_ticket_ungrant(log, ctx->ticket);
out_abort:
ASSERT(XLOG_FORCED_SHUTDOWN(log));
xlog_cil_committed(ctx);
--
2.28.0