libgfapi, timer: Fix a crash seen in timer when glfs_fini was invoked.

The crash is seen when, glfs_init failed for some reason
and glfs_fini was called for cleaning up the partial initialization.

The fix is in two folds:

1. In timer store and restore the THIS, previously
   it was being overwritten.
2. In glfs_free_from_ctx() and glfs_fini() check for
   NULL before destroying.

Change-Id: If40bf69936b873a1da8e348c9d92c66f2f07994b
BUG: 1202290
Signed-off-by: Poornima G <pgurusid@redhat.com>
Reviewed-on: http://review.gluster.org/9895
Reviewed-by: Raghavendra Talur <rtalur@redhat.com>
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Raghavendra Bhat <raghavendra@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>

2 files changed, 21 insertions, 8 deletions

diff --git a/api/src/glfs.c b/api/src/glfs.c
index 02a8984f450..8bd410c716d 100644
--- a/api/src/glfs.c
+++ b/api/src/glfs.c
@@ -664,7 +664,9 @@ priv_glfs_free_from_ctx (struct glfs *fs)
 
         (void) pthread_mutex_destroy (&fs->mutex);
 
-        FREE (fs->volname);
+        if (fs->volname)
+                FREE (fs->volname);
+
         FREE (fs);
 }
 
@@ -934,13 +936,17 @@ pub_glfs_fini (struct glfs *fs)
         }
 
         ctx = fs->ctx;
+        if (!ctx) {
+                goto free_fs;
+        }
+
+        __glfs_entry_fs (fs);
+
         if (ctx->mgmt) {
                 rpc_clnt_disable (ctx->mgmt);
                 ctx->mgmt = NULL;
         }
 
-        __glfs_entry_fs (fs);
-
         call_pool = fs->ctx->pool;
 
         while (countdown--) {
@@ -1069,6 +1075,7 @@ pub_glfs_fini (struct glfs *fs)
         if (glusterfs_ctx_destroy (ctx) != 0)
                 ret = -1;
 
+free_fs:
         glfs_free_from_ctx (fs);
 
 fail:
diff --git a/libglusterfs/src/timer.c b/libglusterfs/src/timer.c
index 928b3681c89..cc47db3b9e1 100644
--- a/libglusterfs/src/timer.c
+++ b/libglusterfs/src/timer.c
@@ -141,6 +141,7 @@ gf_timer_proc (void *ctx)
         gf_timer_registry_t *reg = NULL;
         const struct timespec sleepts = {.tv_sec = 1, .tv_nsec = 0, };
         gf_timer_t *event = NULL;
+        xlator_t   *old_THIS = NULL;
 
         if (ctx == NULL)
         {
@@ -174,11 +175,16 @@ gf_timer_proc (void *ctx)
                                 }
                         }
                         pthread_mutex_unlock (&reg->lock);
-                        if (event->xl)
-                                THIS = event->xl;
-                        if (need_cbk)
-                                event->callbk  (event->data);
-
+                        if (need_cbk) {
+                                if (event->xl) {
+                                        old_THIS = THIS;
+                                        THIS = event->xl;
+                                }
+                                event->callbk (event->data);
+                                if (event->xl) {
+                                        THIS = old_THIS;
+                                }
+                        }
                         else
                                 break;
                 }