features/locks: Avoid race in pl_inode_get

Change-Id: I6c7b878fb43863137aac6552ee66f091534a6296
BUG: 770080
Signed-off-by: Pranith Kumar K <pranithk@gluster.com>
Reviewed-on: http://review.gluster.com/2998
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 25 insertions, 21 deletions

diff --git a/xlators/features/locks/src/common.c b/xlators/features/locks/src/common.c
index 643a7a80db2..b775fcca70b 100644
--- a/xlators/features/locks/src/common.c
+++ b/xlators/features/locks/src/common.c
@@ -437,32 +437,36 @@ pl_inode_get (xlator_t *this, inode_t *inode)
         pl_inode_t *pl_inode = NULL;
         int         ret = 0;
 
-        ret = inode_ctx_get (inode, this,&tmp_pl_inode);
-        if (ret == 0) {
-                pl_inode = (pl_inode_t *)(long)tmp_pl_inode;
-                goto out;
-        }
-        pl_inode = GF_CALLOC (1, sizeof (*pl_inode),
-                              gf_locks_mt_pl_inode_t);
-        if (!pl_inode) {
-                goto out;
-        }
+        LOCK (&inode->lock);
+        {
+                ret = __inode_ctx_get (inode, this, &tmp_pl_inode);
+                if (ret == 0) {
+                        pl_inode = (pl_inode_t *)(long)tmp_pl_inode;
+                        goto unlock;
+                }
+                pl_inode = GF_CALLOC (1, sizeof (*pl_inode),
+                                      gf_locks_mt_pl_inode_t);
+                if (!pl_inode) {
+                        goto unlock;
+                }
 
-        gf_log (this->name, GF_LOG_TRACE,
-                "Allocating new pl inode");
+                gf_log (this->name, GF_LOG_TRACE,
+                        "Allocating new pl inode");
 
-        pthread_mutex_init (&pl_inode->mutex, NULL);
+                pthread_mutex_init (&pl_inode->mutex, NULL);
 
-        INIT_LIST_HEAD (&pl_inode->dom_list);
-        INIT_LIST_HEAD (&pl_inode->ext_list);
-        INIT_LIST_HEAD (&pl_inode->rw_list);
-        INIT_LIST_HEAD (&pl_inode->reservelk_list);
-        INIT_LIST_HEAD (&pl_inode->blocked_reservelks);
-        INIT_LIST_HEAD (&pl_inode->blocked_calls);
+                INIT_LIST_HEAD (&pl_inode->dom_list);
+                INIT_LIST_HEAD (&pl_inode->ext_list);
+                INIT_LIST_HEAD (&pl_inode->rw_list);
+                INIT_LIST_HEAD (&pl_inode->reservelk_list);
+                INIT_LIST_HEAD (&pl_inode->blocked_reservelks);
+                INIT_LIST_HEAD (&pl_inode->blocked_calls);
 
-        inode_ctx_put (inode, this, (uint64_t)(long)(pl_inode));
+                __inode_ctx_put (inode, this, (uint64_t)(long)(pl_inode));
+        }
+unlock:
+        UNLOCK (&inode->lock);
 
-out:
         return pl_inode;
 }