[Ocfs2-devel] [PATCH] ocfs2:fix memory leak in dlm_add_migration_mle
Xue jiufei
xuejiufei at huawei.com
Mon Nov 5 00:45:24 PST 2012
Hi Jeff
于 2012/11/2 22:52, Jeff Liu 写道:
> Hi Jiefei,
>
> On 11/02/2012 04:50 PM, Xue jiufei wrote:
>> After some parallel mount/umount test on ocfs2, we got this: slab error
>> in kmem_cache_destroy(): cache `o2dlm_mle': Can't free all objects.
>>
>> Then we found a memleak situation in dlm_add_migration_mle().
>> When a mle found, it will be removed from dlm->hlist. If there is no
>> pointer to it at that moment, the mle will become an “orphan mle”
>> that no process can find and release.
>>
>> Signed-off-by: Xuejiufei <xuejiufei at huawei.com>
>> ---
>> fs/ocfs2/dlm/dlmmaster.c | 11 ++++++++++-
>> 1 files changed, 10 insertions(+), 1 deletions(-)
>>
>> diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
>> index 005261c..20d2307 100644
>> --- a/fs/ocfs2/dlm/dlmmaster.c
>> +++ b/fs/ocfs2/dlm/dlmmaster.c
>> @@ -284,6 +284,7 @@ static void dlm_init_mle(struct dlm_master_list_entry *mle,
>> mle->master = O2NM_MAX_NODES;
>> mle->new_master = O2NM_MAX_NODES;
>> mle->inuse = 0;
>> + mle->assert_master = 0;
>>
>> BUG_ON(mle->type != DLM_MLE_BLOCK &&
>> mle->type != DLM_MLE_MASTER &&
>> @@ -1743,6 +1744,7 @@ int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
>> u32 flags;
>> int master_request = 0, have_lockres_ref = 0;
>> int ret = 0;
>> + int bit;
>>
>> if (!dlm_grab(dlm))
>> return 0;
>> @@ -1770,7 +1772,11 @@ int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
>> "MLE for it! (%.*s)\n", assert->node_idx,
>> namelen, name);
>> } else {
> Looks good.
> I am being really picky, looks there is no need to move bit variable to
> be function level, i.e.
>
> int bit;
>
> spin_lock(&mle->spinlock);
> mle->assert_master = 1;
> spin_unlock(&mle->spinlock);
> bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
>
> Thanks,
> -Jeff
>> - int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
>> + spin_lock(&mle->spinlock);
>> + mle->assert_master = 1;
>> + spin_unlock(&mle->spinlock);
>> +
>> + bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
>> if (bit >= O2NM_MAX_NODES) {
>> /* not necessarily an error, though less likely.
>> * could be master just re-asserting. */
>> @@ -3081,6 +3087,8 @@ static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
>> /* remove it so that only one mle will be found */
>> __dlm_unlink_mle(dlm, tmp);
>> __dlm_mle_detach_hb_events(dlm, tmp);
>> + if (tmp->type == DLM_MLE_BLOCK && tmp->assert_master == 0)
>> + __dlm_put_mle(tmp);
>> ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
>> mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
>> "telling master to get ref for cleared out mle "
>> @@ -3173,6 +3181,7 @@ static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
>> wake_up(&mle->wq);
>>
>> /* Do not need events any longer, so detach from heartbeat */
>> + __dlm_unlink_mle(dlm, mle);
>> __dlm_mle_detach_hb_events(dlm, mle);
>> __dlm_put_mle(mle);
>> }
>>
>
> .
>
Thank you for the suggestion and I really agree with you.
Here is the patch after modification:
Signed-off-by: Xuejiufei <xuejiufei at huawei.com
---
fs/ocfs2/dlm/dlmmaster.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 005261c..2458b29 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -284,6 +284,7 @@ static void dlm_init_mle(struct dlm_master_list_entry *mle,
mle->master = O2NM_MAX_NODES;
mle->new_master = O2NM_MAX_NODES;
mle->inuse = 0;
+ mle->assert_master = 0;
BUG_ON(mle->type != DLM_MLE_BLOCK &&
mle->type != DLM_MLE_MASTER &&
@@ -1770,7 +1771,12 @@ int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
"MLE for it! (%.*s)\n", assert->node_idx,
namelen, name);
} else {
- int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
+ int bit;
+ spin_lock(&mle->spinlock);
+ mle->assert_master = 1;
+ spin_unlock(&mle->spinlock);
+
+ bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
if (bit >= O2NM_MAX_NODES) {
/* not necessarily an error, though less likely.
* could be master just re-asserting. */
@@ -3081,6 +3087,8 @@ static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
/* remove it so that only one mle will be found */
__dlm_unlink_mle(dlm, tmp);
__dlm_mle_detach_hb_events(dlm, tmp);
+ if (tmp->type == DLM_MLE_BLOCK && tmp->assert_master == 0)
+ __dlm_put_mle(tmp);
ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
"telling master to get ref for cleared out mle "
@@ -3173,6 +3181,7 @@ static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
wake_up(&mle->wq);
/* Do not need events any longer, so detach from heartbeat */
+ __dlm_unlink_mle(dlm, mle);
__dlm_mle_detach_hb_events(dlm, mle);
__dlm_put_mle(mle);
}
--
1.7.8.6
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