From 92952a767ffe126e1dfa548be003ce2b0461065e Mon Sep 17 00:00:00 2001

From: Pranith Kumar K <pkarampu@redhat.com>

Date: Sat, 18 Jul 2015 10:04:13 +0530

Subject: [PATCH 245/245] Revert "timer: fix race between gf_timer_call_cancel() and gf_timer_proc()"

This reverts commit 9b237463a8f5c75cff66364d07278217f8e4e586.

BUG: 1244187

Change-Id: Ibb6c04ab6167071e62c7a33e114b3dd5931825c8

Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>

Reviewed-on: https://code.engineering.redhat.com/gerrit/53266

Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>

Reviewed-by: Kaushal Madappa <kaushal@redhat.com>

---

 libglusterfs/src/timer.c |   48 +++++++++++++++++++++++++++++++--------------

 libglusterfs/src/timer.h |    2 +-

 2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/libglusterfs/src/timer.c b/libglusterfs/src/timer.c

index a4d1890..e103f05 100644

--- a/libglusterfs/src/timer.c

+++ b/libglusterfs/src/timer.c

@@ -85,11 +85,30 @@ gf_timer_call_after (glusterfs_ctx_t *ctx,

 }

 int32_t

+gf_timer_call_stale (gf_timer_registry_t *reg,

+                     gf_timer_t *event)

+{

+        if (reg == NULL || event == NULL) {

+                gf_msg_callingfn ("timer", GF_LOG_ERROR, EINVAL,

+                                  LG_MSG_INVALID_ARG, "invalid argument");

+                return 0;

+        }

+

+        event->next->prev = event->prev;

+        event->prev->next = event->next;

+        event->next = &reg->stale;

+        event->prev = event->next->prev;

+        event->next->prev = event;

+        event->prev->next = event;

+

+        return 0;

+}

+

+int32_t

 gf_timer_call_cancel (glusterfs_ctx_t *ctx,

                       gf_timer_t *event)

 {

         gf_timer_registry_t *reg = NULL;

-        gf_boolean_t fired = _gf_false;

         if (ctx == NULL || event == NULL)

         {

@@ -108,21 +127,13 @@ gf_timer_call_cancel (glusterfs_ctx_t *ctx,

         pthread_mutex_lock (&reg->lock);

         {

-		fired = event->fired;

-		if (fired)

-			goto unlock;

-

                 event->next->prev = event->prev;

                 event->prev->next = event->next;

         }

-unlock:

         pthread_mutex_unlock (&reg->lock);

-	if (!fired) {

-		GF_FREE (event);

-		return 0;

-        }

-        return -1;

+        GF_FREE (event);

+        return 0;

 }

 static inline void __delete_entry (gf_timer_t *event) {

@@ -169,9 +180,7 @@ gf_timer_proc (void *ctx)

                                 at = TS (event->at);

                                 if (event != &reg->active && now >= at) {

                                         need_cbk = 1;

-                                        event->next->prev = event->prev;

-                                        event->prev->next = event->next;

-                                        event->fired = 1;

+                                        gf_timer_call_stale (reg, event);

                                 }

                         }

                         pthread_mutex_unlock (&reg->lock);

@@ -182,7 +191,9 @@ gf_timer_proc (void *ctx)

                                         THIS = event->xl;

                                 }

                                 event->callbk (event->data);

-                                GF_FREE (event);

+                                /*This callbk above would have freed the event

+                                 * by calling timer_cancel, don't ever touch it

+                                 * again*/

                                 if (old_THIS) {

                                         THIS = old_THIS;

                                 }

@@ -204,6 +215,11 @@ gf_timer_proc (void *ctx)

                          * list_head*/

                         __delete_entry (event);

                 }

+

+                while (reg->stale.next != &reg->stale) {

+                        event = reg->stale.next;

+                        __delete_entry (event);

+                }

         }

         pthread_mutex_unlock (&reg->lock);

         pthread_mutex_destroy (&reg->lock);

@@ -232,6 +248,8 @@ gf_timer_registry_init (glusterfs_ctx_t *ctx)

                 pthread_mutex_init (&reg->lock, NULL);

                 reg->active.next = &reg->active;

                 reg->active.prev = &reg->active;

+                reg->stale.next = &reg->stale;

+                reg->stale.prev = &reg->stale;

                 ctx->timer = reg;

                 gf_thread_create (&reg->th, NULL, gf_timer_proc, ctx);

diff --git a/libglusterfs/src/timer.h b/libglusterfs/src/timer.h

index 35d99be..e64b350 100644

--- a/libglusterfs/src/timer.h

+++ b/libglusterfs/src/timer.h

@@ -29,12 +29,12 @@ struct _gf_timer {

         gf_timer_cbk_t    callbk;

         void             *data;

         xlator_t         *xl;

-	gf_boolean_t      fired;

 };

 struct _gf_timer_registry {

         pthread_t        th;

         char             fin;

+        struct _gf_timer stale;

         struct _gf_timer active;

         pthread_mutex_t  lock;

 };

-- 

1.7.1