struct xfs_ail_cursor *cur = &ailp->xa_cursors;
xfs_log_item_t *lip;
xfs_lsn_t lsn;
- xfs_lsn_t target = ailp->xa_target;
+ xfs_lsn_t target;
long tout = 10;
int flush_log = 0;
int stuck = 0;
int push_xfsbufd = 0;
spin_lock(&ailp->xa_lock);
+ target = ailp->xa_target;
xfs_trans_ail_cursor_init(ailp, cur);
lip = xfs_trans_ail_cursor_first(ailp, cur, ailp->xa_last_pushed_lsn);
if (!lip || XFS_FORCED_SHUTDOWN(mp)) {
ailp->xa_last_pushed_lsn = 0;
/*
- * Check for an updated push target before clearing the
- * XFS_AIL_PUSHING_BIT. If the target changed, we've got more
- * work to do. Wait a bit longer before starting that work.
+ * We clear the XFS_AIL_PUSHING_BIT first before checking
+ * whether the target has changed. If the target has changed,
+ * this pushes the requeue race directly onto the result of the
+ * atomic test/set bit, so we are guaranteed that either the
+ * the pusher that changed the target or ourselves will requeue
+ * the work (but not both).
*/
+ clear_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags);
smp_rmb();
- if (ailp->xa_target == target) {
- clear_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags);
+ if (XFS_LSN_CMP(ailp->xa_target, target) == 0 ||
+ test_and_set_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags))
return;
- }
+
tout = 50;
} else if (XFS_LSN_CMP(lsn, target) >= 0) {
/*
* the XFS_AIL_PUSHING_BIT.
*/
smp_wmb();
- ailp->xa_target = threshold_lsn;
+ xfs_trans_ail_copy_lsn(ailp, &ailp->xa_target, &threshold_lsn);
if (!test_and_set_bit(XFS_AIL_PUSHING_BIT, &ailp->xa_flags))
queue_delayed_work(xfs_syncd_wq, &ailp->xa_work, 0);
}