Description of problem:
Snapshot creation with same name on UI throwing 500 Internal Error

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1. Click FileSystems in left pane
2. select one file systems in right pane which has subvolume created
3. Navigate to subvolume
4. click on create snapshot
5. Create a snapshot with name snap1
6. now again create snapshot with snap1

Currently it is throwing 500 Internal error

Cna we give right error message
in the mgr logs we are seeing
debug 2022-07-27T17:32:22.645+0000 7f7ecfba6700  0 [dashboard INFO cephfs] Creating snapshot: /volumes/subvolgroup_1/subvol_1/.snap/snap1
debug 2022-07-27T17:32:22.652+0000 7f7ecfba6700  0 [dashboard ERROR exception] Internal Server Error
Traceback (most recent call last):
  File "/usr/share/ceph/mgr/dashboard/services/exception.py", line 47, in dashboard_exception_handler
    return handler(*args, **kwargs)
  File "/lib/python3.6/site-packages/cherrypy/_cpdispatch.py", line 54, in __call__
    return self.callable(*self.args, **self.kwargs)
  File "/usr/share/ceph/mgr/dashboard/controllers/_base_controller.py", line 258, in inner
    ret = func(*args, **kwargs)
  File "/usr/share/ceph/mgr/dashboard/controllers/_rest_controller.py", line 191, in wrapper
    return func(*vpath, **params)
  File "/usr/share/ceph/mgr/dashboard/controllers/cephfs.py", line 470, in snapshot
    return cfs.mk_snapshot(path, name)
  File "/usr/share/ceph/mgr/dashboard/services/cephfs.py", line 186, in mk_snapshot
    self.cfs.mkdir(snapshot_path, mode)
  File "cephfs.pyx", line 1023, in cephfs.LibCephFS.mkdir
cephfs.ObjectExists: error in mkdir /volumes/subvolgroup_1/subvol_1/.snap/snap1: File exists [Errno 17]


Actual results:


Expected results:


Additional info: