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-rw-r--r--fs/xfs/xfs_trans_ail.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/fs/xfs/xfs_trans_ail.c b/fs/xfs/xfs_trans_ail.c
index d7eebbf71362..5fc2380092c8 100644
--- a/fs/xfs/xfs_trans_ail.c
+++ b/fs/xfs/xfs_trans_ail.c
@@ -487,15 +487,19 @@ out_done:
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 (XFS_LSN_CMP(ailp->xa_target, target) == 0) {
- 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) {
/*