Merge pull request ceph#62708 from rishabh-d-dave/vols-snap-path

mgr/vol: add command to get snapshot path

Reviewed-by: Venky Shankar <[email protected]>

Author: rishabh-d-dave

PendingReleaseNotes

@@ -107,6 +107,10 @@
   `PutBucketPolicy`. Additionally, the root user will always have access to modify
   the bucket policy, even if the current policy explicitly denies access.
 
+* CephFS: The ``ceph fs subvolume snapshot getpath`` command now allows users
+  to get the path of a snapshot of a subvolume. If the snapshot is not present
+  ``ENOENT`` is returned.
+
 * CephFS: The ``ceph fs volume create`` command now allows users to pass
   metadata and data pool names to be used for creating the volume. If either
   is not passed or if either is a non-empty pool, the command will abort.

doc/cephfs/fs-volumes.rst

@@ -635,6 +635,15 @@ otherwise fail (if the snapshot did not exist).
 
 .. note:: if the last snapshot within a snapshot retained subvolume is removed, the subvolume is also removed
 
+Fetching Path of a Snapshot of a Subvolume
+------------------------------------------
+Use a command of the following form to fetch the absolute path of a snapshot of
+a subvolume:
+
+.. prompt:: base #
+
+    ceph fs subvolume snapshot getpath <volname> <subvol_name> <snap_name> [<group_name>]
+
 Listing the Snapshots of a Subvolume
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

qa/tasks/cephfs/test_volumes.py

@@ -5175,6 +5175,123 @@ def test_subvolume_snapshot_create_idempotence(self):
         # verify trash dir is clean
         self._wait_for_trash_empty()
 
+    def get_subvol_uuid(self, subvol_name, group_name=None):
+        '''
+        Return the UUID directory component obtained from the path of
+        subvolume.
+        '''
+        if group_name:
+            cmd = (f'fs subvolume getpath {self.volname} {subvol_name} '
+                   f'{group_name}')
+        else:
+            cmd = f'fs subvolume getpath {self.volname} {subvol_name}'
+
+        subvol_path = self.get_ceph_cmd_stdout(cmd).strip()
+
+        subvol_uuid = os.path.basename(subvol_path)
+        return subvol_uuid
+
+    def test_snapshot_getpath(self):
+        '''
+        Test that "ceph fs subvolume snapshot getpath" command returns path to
+        the specified snapshot in the specified subvolume.
+        '''
+        subvol_name = self._gen_subvol_name()
+        snap_name = self._gen_subvol_snap_name()
+
+        self.run_ceph_cmd(f'fs subvolume create {self.volname} {subvol_name}')
+        sv_uuid = self.get_subvol_uuid(subvol_name)
+        self.run_ceph_cmd(f'fs subvolume snapshot create {self.volname} '
+                          f'{subvol_name} {snap_name}')
+
+        snap_path = self.get_ceph_cmd_stdout(f'fs subvolume snapshot getpath '
+                                             f'{self.volname} {subvol_name} '
+                                             f'{snap_name}').strip()
+        # expected snapshot path
+        exp_snap_path = os.path.join('/volumes', '_nogroup', subvol_name,
+                                     '.snap', snap_name, sv_uuid)
+        self.assertEqual(snap_path, exp_snap_path)
+
+    def test_snapshot_getpath_in_group(self):
+        '''
+        Test that "ceph fs subvolume snapshot getpath" command returns path to
+        the specified snapshot in the specified subvolume in the specified
+        group.
+        '''
+        subvol_name = self._gen_subvol_name()
+        group_name = self._gen_subvol_grp_name()
+        snap_name = self._gen_subvol_snap_name()
+
+        self.run_ceph_cmd(f'fs subvolumegroup create {self.volname} {group_name}')
+        self.run_ceph_cmd(f'fs subvolume create {self.volname} {subvol_name} '
+                          f'{group_name}')
+        sv_uuid = self.get_subvol_uuid(subvol_name, group_name)
+        self.run_ceph_cmd(f'fs subvolume snapshot create {self.volname} '
+                          f'{subvol_name} {snap_name} {group_name}')
+
+        snap_path = self.get_ceph_cmd_stdout(f'fs subvolume snapshot getpath '
+                                             f'{self.volname} {subvol_name} '
+                                             f'{snap_name} {group_name}')\
+                                             .strip()
+        # expected snapshot path
+        exp_snap_path = os.path.join('/volumes', group_name, subvol_name,
+                                     '.snap', snap_name, sv_uuid)
+        self.assertEqual(snap_path, exp_snap_path)
+
+    def test_snapshot_getpath_on_retained_subvol(self):
+        '''
+        Test that "ceph fs subvolume snapshot getpath" command returns path to
+        the specified snapshot in the specified subvolume that was deleted but
+        snapshots on which is retained.
+        '''
+        subvol_name = self._gen_subvol_name()
+        snap_name = self._gen_subvol_snap_name()
+
+        self.run_ceph_cmd(f'fs subvolume create {self.volname} {subvol_name}')
+        sv_uuid = self.get_subvol_uuid(subvol_name)
+        self.run_ceph_cmd(f'fs subvolume snapshot create {self.volname} '
+                          f'{subvol_name} {snap_name}')
+        self.run_ceph_cmd(f'fs subvolume rm {self.volname} {subvol_name} '
+                           '--retain-snapshots')
+
+        snap_path = self.get_ceph_cmd_stdout(f'fs subvolume snapshot getpath '
+                                             f'{self.volname} {subvol_name} '
+                                             f'{snap_name}').strip()
+
+        # expected snapshot path
+        exp_snap_path = os.path.join('/volumes', '_nogroup', subvol_name,
+                                     '.snap', snap_name, sv_uuid)
+        self.assertEqual(snap_path, exp_snap_path)
+
+    def test_snapshot_getpath_on_retained_subvol_in_group(self):
+        '''
+        Test that "ceph fs subvolume snapshot getpath" command returns path to
+        the specified snapshot in the specified subvolume that was deleted but
+        snapshots on which is retained. And the deleted subvolume is located on
+        a non-default group.
+        '''
+        subvol_name = self._gen_subvol_name()
+        group_name = self._gen_subvol_grp_name()
+        snap_name = self._gen_subvol_snap_name()
+
+        self.run_ceph_cmd(f'fs subvolumegroup create {self.volname} {group_name}')
+        self.run_ceph_cmd(f'fs subvolume create {self.volname} {subvol_name} '
+                          f'{group_name}')
+        sv_uuid = self.get_subvol_uuid(subvol_name, group_name)
+        self.run_ceph_cmd(f'fs subvolume snapshot create {self.volname} '
+                          f'{subvol_name} {snap_name} {group_name}')
+        self.run_ceph_cmd(f'fs subvolume rm {self.volname} {subvol_name} '
+                          f'{group_name} --retain-snapshots')
+
+        snap_path = self.get_ceph_cmd_stdout(f'fs subvolume snapshot getpath '
+                                             f'{self.volname} {subvol_name} '
+                                             f'{snap_name} {group_name}')\
+                                             .strip()
+        # expected snapshot path
+        exp_snap_path = os.path.join('/volumes', group_name, subvol_name,
+                                     '.snap', snap_name, sv_uuid)
+        self.assertEqual(snap_path, exp_snap_path)
+
     def test_subvolume_snapshot_info(self):
 
         """

src/pybind/mgr/volumes/fs/operations/template.py

@@ -49,6 +49,7 @@ class SubvolumeOpType(Enum):
     SNAP_CREATE           = 'snap-create'
     SNAP_REMOVE           = 'snap-rm'
     SNAP_LIST             = 'snap-ls'
+    SNAP_GETPATH          = 'snap-getpath'
     SNAP_INFO             = 'snap-info'
     SNAP_PROTECT          = 'snap-protect'
     SNAP_UNPROTECT        = 'snap-unprotect'

src/pybind/mgr/volumes/fs/operations/versions/subvolume_v2.py

@@ -282,6 +282,7 @@ def allowed_ops_by_state(self, vol_state):
                 SubvolumeOpType.INFO,
                 SubvolumeOpType.SNAP_REMOVE,
                 SubvolumeOpType.SNAP_LIST,
+                SubvolumeOpType.SNAP_GETPATH,
                 SubvolumeOpType.SNAP_INFO,
                 SubvolumeOpType.SNAP_PROTECT,
                 SubvolumeOpType.SNAP_UNPROTECT,

src/pybind/mgr/volumes/fs/volume.py

@@ -22,7 +22,7 @@
     list_volumes, open_volume, get_pool_names, get_pool_ids, \
     get_pending_subvol_deletions_count, get_all_pending_clones_count
 from .operations.subvolume import open_subvol, create_subvol, remove_subvol, \
-    create_clone, open_subvol_in_group
+    create_clone, open_subvol_in_group, open_subvol_in_vol
 
 from .vol_spec import VolSpec
 from .exception import VolumeException, ClusterError, ClusterTimeout, \
@@ -789,6 +789,23 @@ def subvolume_snapshot_info(self, **kwargs):
                 ret = self.volume_exception_to_retval(ve)
         return ret
 
+    def subvolume_snapshot_getpath(self, **kwargs):
+        ret        = 0, "", ""
+        volname    = kwargs['vol_name']
+        subvolname = kwargs['sub_name']
+        snapname   = kwargs['snap_name']
+        groupname  = kwargs['group_name']
+
+        try:
+            with open_subvol_in_vol(self, self.volspec, volname, groupname, subvolname,
+                                    SubvolumeOpType.SNAP_GETPATH) \
+                                    as (vol, group, subvol):
+                snap_path = subvol.snapshot_data_path(snapname)
+                ret = 0, snap_path.decode("utf-8"), ""
+        except VolumeException as ve:
+            ret = self.volume_exception_to_retval(ve)
+        return ret
+
     def set_subvolume_snapshot_metadata(self, **kwargs):
         ret        = 0, "", ""
         volname    = kwargs['vol_name']

src/pybind/mgr/volumes/module.py

@@ -468,6 +468,17 @@ class Module(orchestrator.OrchestratorClientMixin, MgrModule):
                     "and optionally, in a specific subvolume group",
             'perm': 'rw'
         },
+        {
+            'cmd': 'fs subvolume snapshot getpath '
+                   'name=vol_name,type=CephString '
+                   'name=sub_name,type=CephString '
+                   'name=snap_name,type=CephString '
+                   'name=group_name,type=CephString,req=false ',
+            'desc': 'Get path for a snapshot of a CephFS subvolume located in '
+                    'a specific volume, and optionally, in a specific '
+                    'subvolume group',
+            'perm': 'r'
+        },
         {
             'cmd': 'fs subvolume resize '
                    'name=vol_name,type=CephString '
@@ -999,6 +1010,13 @@ def _cmd_fs_subvolume_snapshot_ls(self, inbuf, cmd):
                                                 sub_name=cmd['sub_name'],
                                                 group_name=cmd.get('group_name', None))
 
+    @mgr_cmd_wrap
+    def _cmd_fs_subvolume_snapshot_getpath(self, inbuf, cmd):
+        return self.vc.subvolume_snapshot_getpath(vol_name=cmd['vol_name'],
+                                                  sub_name=cmd['sub_name'],
+                                                  snap_name=cmd['snap_name'],
+                                                  group_name=cmd.get('group_name', None))
+
     @mgr_cmd_wrap
     def _cmd_fs_subvolume_resize(self, inbuf, cmd):
         return self.vc.resize_subvolume(vol_name=cmd['vol_name'], sub_name=cmd['sub_name'],