[LU-17833] lru_size is not maintained during umount and remount

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.16.0
• Story Points: 3
• Severity: 3
• Assignee: Di Wang
• Reporter: Di Wang

Description

It looks like lru_size is not maintained during umount & remount, even though the parameter has been added to the parameter llog by "lctl set_param -P"

[testusr@testnode tests]$ sudo ../utils/lctl set_param -P ldlm.namespaces.*mdc*.lru_size=100
[testusr@testnode tests]$ sudo ../utils/lctl get_param ldlm.namespaces.*mdc*.lru_size
ldlm.namespaces.lustre-MDT0000-mdc-ffff9e53a93bc000.lru_size=100
[testusr@testnode tests]$ sudo umount /mnt/lustre
[testusr@testnode tests]$ sh llmountcleanup.sh ^C
[testusr@testnode tests]$ sudo mount -t lustre 10.0.0.131@tcp:/lustre  /mnt/lustre
[testusr@testnode tests]$ sudo ../utils/lctl get_param ldlm.namespaces.*mdc*.lru_size
ldlm.namespaces.lustre-MDT0000-mdc-ffff9e597b29c800.lru_size=0

After checking the code, it looks like parameter llog might be processed before the connection(client to MDS) is established, so even though the lru_resize is disabled by
parameter config log processing (lru_size_store()), but later ptlrpc_connect_set_flags() will reset the flag, which will cause the issue.