[LU-3613] Get parent_fid + name for an entry

• Type: Improvement
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.7.0
• Affects Version/s: Lustre 2.5.0
• Labels: liblustreapi patch
• Assignee: Jinshan Xiong (Inactive)
• Reporter: Thomas LEIBOVICI - CEA (Inactive)

Description

Getting all parent fid + name of an entry currently requires several calls with the current api, and is a big waste of RPCs:
To get all path for an entry, we need to call fid2path,
so this needs to call path2fid first, as fid2path requires a fid argument.
Then, we need to call path2fid again for each path returned by fid2path.

It would be much simpler to provide a wrapper that would directly read and decode link ea information.
This would return all parent_fid+name for a given path.
(this would also implements a fid -> parent_fid+name interface,
by passing a path in .lustre/fid).

I'll submit a patch to be (hopefully) included in 2.5.

Issue Links

• is related to: LU-5837 ll_getparent improvements
• is related to: LU-5613 unused variable in tgt_brw_read()