[PATCH 6/9] xfs: rework xlog_state_do_callback()

Dave Chinner
2021-07-14T03:20:19Z

From: Dave Chinner <dchinner@redhat.com>

Clean it up a bit by factoring and rearranging some of the code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_log.c | 96 ++++++++++++++++++++++++++----------------------
1 file changed, 53 insertions(+), 43 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index f996f51c6cee..302c1ce27974 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -2760,56 +2760,66 @@ xlog_state_iodone_process_iclog(
}
}

+/*
+ * Loop over all the iclogs, running attached callbacks on them. Return true if
+ * we ran any callbacks, indicating that we dropped the icloglock.
+ */
+static bool
+xlog_state_do_iclog_callbacks(
+ struct xlog *log)
+ __releases(&log->l_icloglock)
+ __acquires(&log->l_icloglock)
+{
+ struct xlog_in_core *first_iclog = log->l_iclog;
+ struct xlog_in_core *iclog = first_iclog;
+ bool ran_callback = false;
+
+ do {
+ LIST_HEAD(cb_list);
+
+ if (!xlog_is_shutdown(log)) {
+ if (xlog_state_iodone_process_iclog(log, iclog))
+ break;
+ if (iclog->ic_state != XLOG_STATE_CALLBACK) {
+ iclog = iclog->ic_next;
+ continue;
+ }
+ }
+ list_splice_init(&iclog->ic_callbacks, &cb_list);
+ spin_unlock(&log->l_icloglock);
+
+ trace_xlog_iclog_callbacks_start(iclog, _RET_IP_);
+ xlog_cil_process_committed(&cb_list);
+ trace_xlog_iclog_callbacks_done(iclog, _RET_IP_);
+ ran_callback = true;
+
+ spin_lock(&log->l_icloglock);
+ if (xlog_is_shutdown(log))
+ wake_up_all(&iclog->ic_force_wait);
+ else
+ xlog_state_clean_iclog(log, iclog);
+ iclog = iclog->ic_next;
+ } while (iclog != first_iclog);
+
+ return ran_callback;
+}
+
+
+/*
+ * Loop running iclog completion callbacks until there are no more iclogs in a
+ * state that can run callbacks.
+ */
STATIC void
xlog_state_do_callback(
struct xlog *log)
{
- struct xlog_in_core *iclog;
- struct xlog_in_core *first_iclog;
- bool cycled_icloglock;
int flushcnt = 0;
int repeats = 0;

spin_lock(&log->l_icloglock);
- do {
- /*
- * Scan all iclogs starting with the one pointed to by the
- * log. Reset this starting point each time the log is
- * unlocked (during callbacks).
- *
- * Keep looping through iclogs until one full pass is made
- * without running any callbacks.
- */
- cycled_icloglock = false;
- first_iclog = log->l_iclog;
- iclog = first_iclog;
-
- do {
- LIST_HEAD(cb_list);
-
- if (!xlog_is_shutdown(log)) {
- if (xlog_state_iodone_process_iclog(log, iclog))
- break;
- if (iclog->ic_state != XLOG_STATE_CALLBACK) {
- iclog = iclog->ic_next;
- continue;
- }
- }
- list_splice_init(&iclog->ic_callbacks, &cb_list);
- spin_unlock(&log->l_icloglock);
-
- trace_xlog_iclog_callbacks_start(iclog, _RET_IP_);
- xlog_cil_process_committed(&cb_list);
- trace_xlog_iclog_callbacks_done(iclog, _RET_IP_);
- cycled_icloglock = true;
-
- spin_lock(&log->l_icloglock);
- if (xlog_is_shutdown(log))
- wake_up_all(&iclog->ic_force_wait);
- else
- xlog_state_clean_iclog(log, iclog);
- iclog = iclog->ic_next;
- } while (iclog != first_iclog);
+ while (xlog_state_do_iclog_callbacks(log)) {
+ if (xlog_is_shutdown(log))
+ break;

if (++repeats > 5000) {
flushcnt += repeats;
@@ -2818,7 +2828,7 @@ xlog_state_do_callback(
"%s: possible infinite loop (%d iterations)",
__func__, flushcnt);
}
- } while (!xlog_is_shutdown(log) && cycled_icloglock);
+ }

if (log->l_iclog->ic_state == XLOG_STATE_ACTIVE ||
xlog_is_shutdown(log))
--
2.31.1