Ceph » rbd

there maybe a bug on ceph-immutable-cache when handling volume snapshot with a long name.
reproduce：
1.create a volume with a long name :
volumes/volume-b5ee6d02-add6-4c24-973c-63d0fbee6495

2.take a snap on volume:
volumes/volume-b5ee6d02-add6-4c24-973c-63d0fbee6495@snapshot-b3d28a16-d8cc-4bf4-9c3c-45e69d2f569c

3.create a volume using step 2 snapshot:
volumes/volume-83281ebd-2149-45f4-995b-9db256d662b1

4.take a snapshot on step 3 volume:
volumes/volume-83281ebd-2149-45f4-995b-9db256d662b1@snapshot-890f5077-e119-4a35-9bc3-69e87ae42bd5

5.create a volume using step 4 snapshot:
volumes/volume-94d34de3-ea69-41e9-ad14-40a8f63a3faa

6.enable ceph-immtable-object-cache,and then any operation on volume volumes/volume-94d34de3-ea69-41e9-ad14-40a8f63a3faa will stuck.

disable ceph-immtable-object-cache：
[root@local _{]# rbd --id cinder info volumes/volume-94d34de3-ea69-41e9-ad14-40a8f63a3faa
rbd image 'volume-94d34de3-ea69-41e9-ad14-40a8f63a3faa':
size 40 GiB in 10240 objects
order 22 (4 MiB objects)
snapshot_count: 0
id: 6ea2279dd8ecdb
block_name_prefix: rbd_data.6ea2279dd8ecdb
format: 2
features: layering, exclusive-lock, object-map, fast-diff, deep-flatten
op_features:
flags:
create_timestamp: Wed Dec 30 10:26:14 2020
access_timestamp: Wed Dec 30 10:26:14 2020
modify_timestamp: Wed Dec 30 10:26:14 2020
parent: volumes/volume-83281ebd-2149-45f4-995b-9db256d662b1@snapshot-890f5077-e119-4a35-9bc3-69e87ae42bd5
overlap: 40 GiB
[root@local ~]# rbd --id cinder info volumes/volume-83281ebd-2149-45f4-995b-9db256d662b1
rbd image 'volume-83281ebd-2149-45f4-995b-9db256d662b1':
size 40 GiB in 10240 objects
order 22 (4 MiB objects)
snapshot_count: 1
id: 6e54041e80e9f2
block_name_prefix: rbd_data.6e54041e80e9f2
format: 2
features: layering, exclusive-lock, object-map, fast-diff, deep-flatten
op_features:
flags:
create_timestamp: Wed Dec 30 10:09:33 2020
access_timestamp: Wed Dec 30 11:17:01 2020
modify_timestamp: Wed Dec 30 13:57:40 2020
parent: volumes/volume-b5ee6d02-add6-4c24-973c-63d0fbee6495@snapshot-b3d28a16-d8cc-4bf4-9c3c-45e69d2f569c
overlap: 40 GiB
[root@local}]# rbd --id cinder info volumes/volume-b5ee6d02-add6-4c24-973c-63d0fbee6495
rbd image 'volume-b5ee6d02-add6-4c24-973c-63d0fbee6495':
size 40 GiB in 10240 objects
order 22 (4 MiB objects)
snapshot_count: 2
id: e982d5d09cbf97
block_name_prefix: rbd_data.e982d5d09cbf97
format: 2
features: layering, exclusive-lock, object-map, fast-diff, deep-flatten
op_features:
flags:
create_timestamp: Thu Dec 24 16:39:54 2020
access_timestamp: Wed Dec 30 12:28:30 2020
modify_timestamp: Mon Dec 28 10:03:10 2020

then enable ceph-immutable-object-cache,request on volumes/volume-94d34de3-ea69-41e9-ad14-40a8f63a3faa will stuck：
[root@local _{]# rbd --id cinder info volumes/volume-94d34de3-ea69-41e9-ad14-40a8f63a3faa
^C
[root@local}]# rbd --id cinder info volumes/volume-83281ebd-2149-45f4-995b-9db256d662b1
rbd image 'volume-83281ebd-2149-45f4-995b-9db256d662b1':
size 40 GiB in 10240 objects
order 22 (4 MiB objects)
snapshot_count: 1
id: 6e54041e80e9f2
block_name_prefix: rbd_data.6e54041e80e9f2
format: 2
features: layering, exclusive-lock, object-map, fast-diff, deep-flatten
op_features:
flags:
create_timestamp: Wed Dec 30 10:09:33 2020
access_timestamp: Wed Dec 30 11:17:01 2020
modify_timestamp: Wed Dec 30 14:03:11 2020
parent: volumes/volume-b5ee6d02-add6-4c24-973c-63d0fbee6495@snapshot-b3d28a16-d8cc-4bf4-9c3c-45e69d2f569c
overlap: 40 GiB