[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()

Comments

[Henri Doreau (Inactive)]

To track the follow-up patch.

[Peter Jones]

I think that would be best. We can link the new ticket to this one

[Henri Doreau (Inactive)]

There'll be a follow-up patch to implement improvements the reviewers suggested on gerrit. Shall I open a new ticket for that?

[Peter Jones]

Landed for 2.7

[Thomas LEIBOVICI - CEA (Inactive)]

Since 2.6.0, definitions of link_ea* structures is no longer part of installed headers accessible for client applications (previously in lustre_idl.h).
This is definitely cleaner, but now there is no possible workaround to decode linkea directly as a client application.
So this patch (http://review.whamcloud.com/7069) becomes a requirement to get parent FID for an entry in Lustre 2.6.

[Thomas LEIBOVICI - CEA (Inactive)]

The change has Jenkins and Maloo green lights - if you can take a look at it. Thanks.

[Thomas LEIBOVICI - CEA (Inactive)]

pushed as change: http://review.whamcloud.com/7069