[LU-7057] use stronger flags when opening volatile files

• Type: Bug
• Resolution: Fixed
• Priority: Critical
• Fix Version/s: Lustre 2.8.0
• Severity: 3
• Assignee: John Hammond
• Reporter: John Hammond

Description

Existing files with volatile-ish names may be accidentally opened by llapi_create_volatile(). This is not the intent so disallow this behavior but using O_EXCL and O_NOFOLLOW.