mds: restrict path that walks into snapdir

The zero-length component (stands for snapdir) must be at very
beginning of path. This allow us to easily check if a client request
want to access snapshot

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>

diff --git a/src/include/filepath.h b/src/include/filepath.h
index 832016ac1bc89e21ac202b71ba83ee778e748adf..7241e5e0cf7fcfb50a24c2448fe5e5dfa0c093d3 100644 (file)
--- a/src/include/filepath.h
+++ b/src/include/filepath.h
@@ -230,6 +230,11 @@ class filepath {
 
     return false;
   }
+
+  bool is_last_snap() const {
+    // walk into snapdir?
+    return depth() > 0 && bits[0].length() == 0;
+  }
 };
 
 WRITE_CLASS_ENCODER(filepath)

diff --git a/src/mds/MDCache.cc b/src/mds/MDCache.cc
index ea3c4e55de8f263ace5ca3a4512d3b6aca9e262a..7a722b19ab6596036ee8e749a2468063be58b31d 100644 (file)
--- a/src/mds/MDCache.cc
+++ b/src/mds/MDCache.cc
@@ -8107,7 +8107,7 @@ int MDCache::path_traverse(MDRequestRef& mdr, MDSContextFactory& cf,
     // walk into snapdir?
     if (path[depth].length() == 0) {
       dout(10) << "traverse: snapdir" << dendl;
-      if (!mdr)
+      if (!mdr || depth > 0) // snapdir must be the first component
        return -EINVAL;
       snapid = CEPH_SNAPDIR;
       mdr->snapid = snapid;