[PATCH 22/45] xfs: embed the xlog_op_header in the commit record

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

Remove the final case where xlog_write() has to prepend an opheader
to a log transaction. Similar to the start record, the commit record
is just an empty opheader with a XLOG_COMMIT_TRANS type, so we can
just make this the payload for the region being passed to
xlog_write() and remove the special handling in xlog_write() for
the commit record.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/xfs_log.c | 33 +++++++++++++++------------------
1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 94711b9ff007..c2e69a1f5cad 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1529,9 +1529,14 @@ xlog_commit_record(
struct xlog_in_core **iclog,
xfs_lsn_t *lsn)
{
+ struct xlog_op_header ophdr = {
+ .oh_clientid = XFS_TRANSACTION,
+ .oh_tid = cpu_to_be32(ticket->t_tid),
+ .oh_flags = XLOG_COMMIT_TRANS,
+ };
struct xfs_log_iovec reg = {
- .i_addr = NULL,
- .i_len = 0,
+ .i_addr = &ophdr,
+ .i_len = sizeof(struct xlog_op_header),
.i_type = XLOG_REG_TYPE_COMMIT,
};
struct xfs_log_vec vec = {
@@ -1543,6 +1548,8 @@ xlog_commit_record(
if (XLOG_FORCED_SHUTDOWN(log))
return -EIO;

+ /* account for space used by record data */
+ ticket->t_curr_res -= reg.i_len;
error = xlog_write(log, &vec, ticket, lsn, iclog, XLOG_COMMIT_TRANS);
if (error)
xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR);
@@ -2148,11 +2155,10 @@ xlog_write_calc_vec_length(

/* Don't account for regions with embedded ophdrs */
if (optype && headers > 0) {
- if (optype & XLOG_UNMOUNT_TRANS)
- headers--;
+ headers--;
if (optype & XLOG_START_TRANS) {
- ASSERT(headers >= 2);
- headers -= 2;
+ ASSERT(headers >= 1);
+ headers--;
}
}

@@ -2362,14 +2368,6 @@ xlog_write(
int data_cnt = 0;
int error = 0;

- /*
- * 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
- * header that gets written. Hence we always have to account for an
- * extra xlog_op_header here for commit records.
- */
- if (optype & XLOG_COMMIT_TRANS)
- ticket->t_curr_res -= sizeof(struct xlog_op_header);
if (ticket->t_curr_res < 0) {
xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES,
"ctx ticket reservation ran out. Need to up reservation");
@@ -2433,14 +2431,13 @@ xlog_write(
/*
* The XLOG_START_TRANS has embedded ophdrs for the
* start record and transaction header. They will always
- * be the first two regions in the lv chain.
+ * be the first two regions in the lv chain. Commit and
+ * unmount records also have embedded ophdrs.
*/
- if (optype & XLOG_START_TRANS) {
+ if (optype) {
ophdr = reg->i_addr;
if (index)
optype &= ~XLOG_START_TRANS;
- } else if (optype & XLOG_UNMOUNT_TRANS) {
- ophdr = reg->i_addr;
} else {
ophdr = xlog_write_setup_ophdr(log, ptr,
ticket, optype);
--
2.28.0