[LU-6667] ll_getname allocates too big of a buffer

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.8.0
• Severity: 3
• Assignee: WC Triage
• Reporter: Oleg Drokin

Description

__getname used in ll_getname allocated PATH_MAX sized 4k buffer that is overkill.
In fact we only need a single component of the pathname that could not be longer than 255 bytes, so only allocating 256 bytes should be enough.
Additionally need to check for strncpy_from_user negative return values while at that.