You should restore the file by copying it not from /ifs/.snapshot but from the original directory in its .snapshot directory.  This should resolve the permissions issue;  Adam is correct, /ifs/.snapshot is owned by root whereas the directory /ifs/is4/HDFS/elz_uat/tmp/test/d1/.snapshot  should have the same permissions as the parent d1 directory.  To verify, cd to /ifs/is4/HDFS/elz_uat/tmp/test/d1/.snapshot and have a look.  You should see a directory called snap_temp_d1_25nov in there, and the files in that directory.  cp the file of concern from there to wherever you like.  cheers Rob 
is4-1$ ls -ltr /ifs/is4/HDFS/elz_uat/tmp/testtotal 30drwxr-xr-x    2 gpadmin  hadoop  26 Nov 20 09:04 d1drwxr-xr-x    2 gpadmin  hadoop  27 Nov 20 09:04 d2-rw-r--r--    1 gpadmin  hadoop   6 Nov 20 09:04 test2.csvis4-1$ isi snapshot snapshots create snap_temp_d1_25nov /ifs/is4/HDFS/elz_uat/tmp/test/d1is4-1$ isi snapshot snapshots view snap_temp_d1_25nov           ID: 47215        Name: snap_temp_d1_25nov        Path: /ifs/is4/HDFS/elz_uat/tmp/test/d1   Has Locks: No    Schedule: -       Alias: -     Created: 2014-11-25T15:16:37     Expires: -        Size: 0bShadow Bytes: 0b   % Reserve: 0.00%% Filesystem: 0.00%       State: active --- is4-1$ isi auth idIds-------------------------------------------------------------------ID Type          ID                                                -------------------------------------------------------------------UID              UID:54545                                         User SID         SID:S-1-5-21-4237034972-1548648221-2056507326-1014GID              GID:54544                                         Group SID        SID:S-1-5-21-4237034972-1548648221-2056507326-1008On Disk User ID  UID:54545                                         On Disk Group ID GID:54544                                         Additional ID    SID:S-1-5-11                                      -------------------------------------------------------------------Total: 7 Privileges--------------------------------------ID                 Name     Access    --------------------------------------ISI_PRIV_LOGIN_SSH SSH      Read only ISI_PRIV_SNAPSHOT  Snapshot Read/writeISI_PRIV_SYNCIQ    SyncIQ   Read/write--------------------------------------Total: 1 Zone Information----------------------------------------------------------------------Zone ID  ZID  Protocol  Local Address  Remote Address  Ifs Restricted ----------------------------------------------------------------------System   1    17        10.171.234.128 10.171.234.25   False          ----------------------------------------------------------------------   is4-1$ ls /ifs/.snapshot/snap_temp_d1_25novls: /ifs/.snapshot/snap_temp_d1_25nov: Permission deniedis4-1$ cp /ifs/.snapshot/snap_temp_d1_25nov /ifs/is4/HDFS/elz_uat/tmp/test/d2cp: /ifs/.snapshot/snap_temp_d1_25nov: Permission denied
Please help. I am trying to restore a file from the snapshot. I am running into 
permission issue.