[LU-15381] Obtain file size information under locks for HSM release

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.15.0
• Severity: 3
• Assignee: Qian Yingjin
• Reporter: Qian Yingjin

Description

In HSM release, it obtains file size and blocks information via @ll_merge_attr without any lock protection, it may get the wrong file size.

we found a bug that a HSM restore followed by a HSM release will set the file size with 0 wrongly.