libcephfs: getcwd after chdir for API constraint

libcephfs semantics require that the old path to the cwd be returned when
getcwd is encounters an unlinked directory in the current working directory.

Signed-off-by: Patrick Donnelly <[email protected]>

Author: batrick

src/libcephfs.cc

@@ -322,7 +322,15 @@ struct ceph_mount_info
 
   int chdir(const char *to, const UserPerm& perms)
   {
-    return client->chdir(to, perms);
+    int rc = client->chdir(to, perms);
+    if (rc == 0) {
+      /* Current API requires "cwd" to be refreshed after every chdir so that
+       * getcwd on an unlinked cwd will still return the old path. Note:
+       * Client::getcwd now returns an error but leaves the "cwd" string
+       * unmodified for this purpose. */
+      client->getcwd(cwd, perms);
+    }
+    return rc;
   }
 
   CephContext *get_ceph_context() const {