libglusterfsclient: traverse the vmplist during fini only if any entries are mounted.

- the vmplist.list is inited only during mounting of first entry. Hence doing
    a list traversal when no vmpentries are present, results in a segfault.

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 282 (segfault of applications using booster observed when the application does not mount any vmps.)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=282

1 files changed, 8 insertions, 5 deletions

diff --git a/libglusterfsclient/src/libglusterfsclient.c b/libglusterfsclient/src/libglusterfsclient.c
index 32059123dd2..419944af6b5 100755
--- a/libglusterfsclient/src/libglusterfsclient.c
+++ b/libglusterfsclient/src/libglusterfsclient.c
@@ -1782,11 +1782,14 @@ glusterfs_umount_all (void)
 
         pthread_mutex_lock (&vmplock);
         {
-                list_for_each_entry_safe (entry, tmp, &vmplist.list, list) {
-                        /* even if there are errors, continue with other
-                           mounts
-                        */
-                        _libgf_umount (entry->vmp);
+                if (vmplist.entries > 0) {
+                        list_for_each_entry_safe (entry, tmp, &vmplist.list,
+                                                  list) {
+                                /* even if there are errors, continue with other
+                                   mounts
+                                */
+                                _libgf_umount (entry->vmp);
+                        }
                 }
         }
         pthread_mutex_unlock (&vmplock);