From 418f763303ec4003f4b805867ff306a2e43bca76 Mon Sep 17 00:00:00 2001 From: Krishnan Parthasarathi Date: Mon, 20 May 2013 17:17:05 +0530 Subject: syncop: Remove task from syncbarrier's waitq before 'wake' Backport of http://review.gluster.org/5047 Removing task from syncbarrier's waitq after wake could result in a subsequent syncbarrier_wake, wake'ing up the already running task. This fix makes the removal from waitq and wake 'atomic' The root cause and the fix are similar in spirit to what was observed in synclock's waitq implementation. Change-Id: I7dd9e6ad5945742bcda20eb5a06a9376bb18528e BUG: 948686 Signed-off-by: Krishnan Parthasarathi Reviewed-on: http://review.gluster.org/5054 Tested-by: Gluster Build System Reviewed-by: Vijay Bellur --- libglusterfs/src/syncop.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) (limited to 'libglusterfs') diff --git a/libglusterfs/src/syncop.c b/libglusterfs/src/syncop.c index aa46f6219..964e6dd2a 100644 --- a/libglusterfs/src/syncop.c +++ b/libglusterfs/src/syncop.c @@ -688,13 +688,10 @@ __syncbarrier_wait (struct syncbarrier *barrier, int waitfor) if (task) { /* called within a synctask */ list_add_tail (&task->waitq, &barrier->waitq); - { - pthread_mutex_unlock (&barrier->guard); - synctask_yawn (task); - synctask_yield (task); - pthread_mutex_lock (&barrier->guard); - } - list_del_init (&task->waitq); + pthread_mutex_unlock (&barrier->guard); + synctask_yawn (task); + synctask_yield (task); + pthread_mutex_lock (&barrier->guard); } else { /* called by a non-synctask */ pthread_cond_wait (&barrier->cond, &barrier->guard); @@ -737,6 +734,7 @@ __syncbarrier_wake (struct syncbarrier *barrier) pthread_cond_signal (&barrier->cond); if (!list_empty (&barrier->waitq)) { task = list_entry (barrier->waitq.next, struct synctask, waitq); + list_del_init (&task->waitq); synctask_wake (task); } -- cgit