Use direct lctl device calls for snapshots

[jgrund]

Signed-off-by: Joe Grund jgrund@whamcloud.io

---

This change is 

[johnsonw]

[root@adm tmp]# iml snapshot list fs
+------------+----------+---------------------------------+-----------+---------+
| Filesystem | Snapshot | Creation Time                   | State     | Comment |
+============+==========+=================================+===========+=========+
| fs         | test     | Fri, 06 Nov 2020 22:54:55 +0000 | unmounted | ---     |
+------------+----------+---------------------------------+-----------+---------+

[root@mds1 ~]# iml-agent snapshot list fs-MDT0000
[Snapshot { filesystem_name: "fs", snapshot_name: "test", snapshot_fsname: "2c1accd5", modify_time: 2020-11-06T22:54:55Z, create_time: 2020-11-06T22:54:55Z, mounted: false, comment: None }]

[root@adm tmp]# iml snapshot destroy fs test
[1/1]   ✔ Destroying snapshot successful
[root@adm tmp]# iml snapshot list fs

[root@adm tmp]#

[johnsonw]

This is mostly working, but I see one problem still. When going from unmounted to mounted, the iml-agent will show this properly but it is not propagated up to the manager and reflected in the database. It may have something to do with how the daemon is working. I'm currently investigating.

[johnsonw]

The snapshot mounting is now being reflected correctly:

[root@adm tmp]# iml snapshot list fs
+------------+----------+---------------------------------+---------+---------+
| Filesystem | Snapshot | Creation Time                   | State   | Comment |
+============+==========+=================================+=========+=========+
| fs         | test     | Tue, 10 Nov 2020 22:19:27 +0000 | mounted | ---     |
+------------+----------+---------------------------------+---------+---------+

[johnsonw]

Testing update:

chroma=> select * from snapshot;
 id | filesystem_name | snapshot_name |      create_time       |      modify_time       | snapshot_fsname | mounted | comment
----+-----------------+---------------+------------------------+------------------------+-----------------+---------+---------
  1 | fs              | test          | 2020-11-11 21:12:28+00 | 2020-11-11 21:12:28+00 | 7c30140b        | t       |
(1 row)

chroma=> \q
[root@adm tmp]# iml snapshot list fs
+------------+----------+---------------------------------+---------+---------+
| Filesystem | Snapshot | Creation Time                   | State   | Comment |
+============+==========+=================================+=========+=========+
| fs         | test     | Wed, 11 Nov 2020 21:12:28 +0000 | mounted | ---     |
+------------+----------+---------------------------------+---------+---------+

[root@adm tmp]# iml snapshot unmount fs test
[1/1]   ✔ Unmounting snapshot successful

...

[root@adm tmp]# iml snapshot list fs
+------------+----------+---------------------------------+-----------+---------+
| Filesystem | Snapshot | Creation Time                   | State     | Comment |
+============+==========+=================================+===========+=========+
| fs         | test     | Wed, 11 Nov 2020 21:12:28 +0000 | unmounted | ---     |
+------------+----------+---------------------------------+-----------+---------+

[johnsonw]

Testing with multiple snapshots:

[root@adm tmp]# iml snapshot create fs test2
[1/1]   ✔ Creating snapshot successful
[root@adm tmp]# iml snapshot list fs
+------------+----------+---------------------------------+-----------+---------+
| Filesystem | Snapshot | Creation Time                   | State     | Comment |
+============+==========+=================================+===========+=========+
| fs         | test     | Wed, 11 Nov 2020 21:12:28 +0000 | unmounted | ---     |
+------------+----------+---------------------------------+-----------+---------+
| fs         | test2    | Wed, 11 Nov 2020 21:43:16 +0000 | unmounted |         |
+------------+----------+---------------------------------+-----------+---------+

[root@adm tmp]# iml snapshot mount fs test2
[1/1]   ✔ Mounting snapshot successful
[root@adm tmp]# iml snapshot list fs
+------------+----------+---------------------------------+-----------+---------+
| Filesystem | Snapshot | Creation Time                   | State     | Comment |
+============+==========+=================================+===========+=========+
| fs         | test     | Wed, 11 Nov 2020 21:12:28 +0000 | unmounted | ---     |
+------------+----------+---------------------------------+-----------+---------+
| fs         | test2    | Wed, 11 Nov 2020 21:43:16 +0000 | mounted   |         |
+------------+----------+---------------------------------+-----------+---------+

[root@adm tmp]# iml snapshot create fs2 test3
[1/1]   ✔ Creating snapshot successful
[root@adm tmp]# iml snapshot list fs
+------------+----------+---------------------------------+-----------+---------+
| Filesystem | Snapshot | Creation Time                   | State     | Comment |
+============+==========+=================================+===========+=========+
| fs         | test     | Wed, 11 Nov 2020 21:12:28 +0000 | unmounted | ---     |
+------------+----------+---------------------------------+-----------+---------+
| fs         | test2    | Wed, 11 Nov 2020 21:43:16 +0000 | mounted   |         |
+------------+----------+---------------------------------+-----------+---------+

[root@adm tmp]# iml snapshot list fs2
+------------+----------+---------------------------------+-----------+---------+
| Filesystem | Snapshot | Creation Time                   | State     | Comment |
+============+==========+=================================+===========+=========+
| fs2        | test3    | Wed, 11 Nov 2020 21:44:26 +0000 | unmounted | ---     |
+------------+----------+---------------------------------+-----------+---------+

[root@adm tmp]# iml snapshot mount fs2 test3
[1/1]   ✔ Mounting snapshot successful
[root@adm tmp]# iml snapshot list fs2
+------------+----------+---------------------------------+---------+---------+
| Filesystem | Snapshot | Creation Time                   | State   | Comment |
+============+==========+=================================+=========+=========+
| fs2        | test3    | Wed, 11 Nov 2020 21:44:26 +0000 | mounted | ---     |
+------------+----------+---------------------------------+---------+---------+

[root@adm tmp]# iml snapshot list fs2
+------------+----------+---------------------------------+---------+---------+
| Filesystem | Snapshot | Creation Time                   | State   | Comment |
+============+==========+=================================+=========+=========+
| fs2        | test3    | Wed, 11 Nov 2020 21:44:26 +0000 | mounted | ---     |
+------------+----------+---------------------------------+---------+---------+

[root@adm tmp]# iml snapshot unmount fs2 test3
[1/1]   ✔ Unmounting snapshot successful
[root@adm tmp]# iml snapshot destroy fs2 test3
[1/1]   ✔ Destroying snapshot successful
[root@adm tmp]# iml snapshot create fs2 test
[1/1]   ✔ Creating snapshot successful
[root@adm tmp]# iml snapshot list fs2
+------------+----------+---------------------------------+-----------+---------+
| Filesystem | Snapshot | Creation Time                   | State     | Comment |
+============+==========+=================================+===========+=========+
| fs2        | test     | Wed, 11 Nov 2020 21:51:37 +0000 | unmounted | ---     |
+------------+----------+---------------------------------+-----------+---------+

[root@adm tmp]# iml snapshot mount fs2 test
[1/1]   ✔ Mounting snapshot successful
[root@adm tmp]# iml snapshot list fs2
+------------+----------+---------------------------------+---------+---------+
| Filesystem | Snapshot | Creation Time                   | State   | Comment |
+============+==========+=================================+=========+=========+
| fs2        | test     | Wed, 11 Nov 2020 21:51:37 +0000 | mounted | ---     |
+------------+----------+---------------------------------+---------+---------+

[johnsonw]

Test successfully built here: https://build.whamcloud.com/view/IML/job/manager-for-lustre/2893/

[nlinker]

Reviewed 4 of 7 files at r1, 6 of 8 files at r2, 2 of 2 files at r4, 6 of 6 files at r5.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @johnsonw)