[PATCH 02/11] xfs: re-order initial space accounting checks in xlog_write

Dave Chinner
2020-03-04T07:54:06Z

From: Dave Chinner <dchinner@redhat.com>

Commit and unmount records records do not need start records to be
written, so rearrange the logic in xlog_write() to remove the need
to check for XLOG_TIC_INITED to determine if we should account for
the space used by a start record.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_log.c | 35 +++++++++++------------------------
1 file changed, 11 insertions(+), 24 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 5b0568a86c07..d6c42954b70c 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -2381,10 +2381,10 @@ xlog_write(
uint flags)
{
struct xlog_in_core *iclog = NULL;
- struct xfs_log_iovec *vecp;
- struct xfs_log_vec *lv;
+ struct xfs_log_vec *lv = log_vector;
+ struct xfs_log_iovec *vecp = lv->lv_iovecp;
+ int index = 0;
int len;
- int index;
int partial_copy = 0;
int partial_copy_len = 0;
int contwr = 0;
@@ -2393,27 +2393,17 @@ xlog_write(
int error = 0;
int start_rec_size = sizeof(struct xlog_op_header);

- *start_lsn = 0;
-
-
/*
- * Region headers and bytes are already accounted for.
- * We only need to take into account start records and
- * split regions in this function.
+ * If this is a commit or unmount transaction, we don't need a start
+ * record to be written. We do, however, have to account for the
+ * commit or unmount header that gets written. Hence we always have
+ * to account for an extra xlog_op_header here.
*/
- if (ticket->t_flags & XLOG_TIC_INITED) {
- ticket->t_curr_res -= sizeof(xlog_op_header_t);
+ ticket->t_curr_res -= sizeof(xlog_op_header_t);
+ if (ticket->t_flags & XLOG_TIC_INITED)
ticket->t_flags &= ~XLOG_TIC_INITED;
- }
-
- /*
- * Commit record headers need to be accounted for. These
- * come in as separate writes so are easy to detect.
- */
- if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS)) {
- ticket->t_curr_res -= sizeof(xlog_op_header_t);
+ if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS))
start_rec_size = 0;
- }

if (ticket->t_curr_res < 0) {
xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
@@ -2423,10 +2413,7 @@ xlog_write(
}

len = xlog_write_calc_vec_length(ticket, log_vector, start_rec_size);
-
- index = 0;
- lv = log_vector;
- vecp = lv->lv_iovecp;
+ *start_lsn = 0;
while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) {
void *ptr;
int log_offset;
--
2.24.0.rc0