From 6b2216ebcce5f699b51d7d10b4100eef2dcbd5d0 Mon Sep 17 00:00:00 2001 From: zhen Date: Fri, 20 May 2022 15:57:53 +0800 Subject: Fix inappropriate logic in memcachedlock.release() Whether 'was_deleted' was 'TRUE' or not, eventually we have to remove self from '_acquired_locks'. For example: 1. App #1 with coordinator 'A' wants to release lock "b" 2. 'self.coord.client.delete()' failed for some reason(.e.g, BrokenPipeError,MemcacheUnexpectedCloseError) 3. According to the former logic,lock "b" will not remove from "_acquired_locks", so "self.heartbeat()" will make it alive forever until App #1 was down or lock "b" turned expired. 4. Now App #1 with coordinator 'A' wants to acquire lock "c", who have the same lock-name with lock "b",It is clear that this will fail and prevent the locked program from continuing to execute. Change-Id: I6fc33b8e0a88510027bcfc30d1504489d2a91b4e --- .../notes/memcached-fix-lock-release-I6fc33b8e0a88510.yaml | 4 ++++ tooz/drivers/memcached.py | 9 +++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) create mode 100644 releasenotes/notes/memcached-fix-lock-release-I6fc33b8e0a88510.yaml diff --git a/releasenotes/notes/memcached-fix-lock-release-I6fc33b8e0a88510.yaml b/releasenotes/notes/memcached-fix-lock-release-I6fc33b8e0a88510.yaml new file mode 100644 index 0000000..aefd26c --- /dev/null +++ b/releasenotes/notes/memcached-fix-lock-release-I6fc33b8e0a88510.yaml @@ -0,0 +1,4 @@ +--- +fixes: + - | + Fixs inappropriate logic in memcachedlock.release() \ No newline at end of file diff --git a/tooz/drivers/memcached.py b/tooz/drivers/memcached.py index 1cefd95..7cc40a9 100644 --- a/tooz/drivers/memcached.py +++ b/tooz/drivers/memcached.py @@ -150,11 +150,16 @@ class MemcachedLock(locking.Lock): # it being done in the client side (non-atomic). value = self.coord.client.get(self.name) if value != self.coord._member_id: + # NOTE(zhen): Although ``member_ id`` is different, self lock + # object needs to be removed from'_ acquired_locks' because it + # has the same key. + self.coord._acquired_locks.remove(self) return False else: + # NOTE(zhen): Whether 'was_deleted' was 'TRUE' or not, + # eventually we have to remove self from '_acquired_locks'. was_deleted = self.coord.client.delete(self.name, noreply=False) - if was_deleted: - self.coord._acquired_locks.remove(self) + self.coord._acquired_locks.remove(self) return was_deleted @_translate_failures -- cgit v1.2.1