[LU-9053] standardize error code returned by lustreapi

• Status: Closed
• Project: Lustre
• Type: Improvement
• Priority: Minor
• Reporter: Jinshan Xiong (Inactive)
• Assignee: WC Triage
• Resolution: Fixed

Description

right now it's pretty random. Sometimes the APIs return -errno, sometimes they set errno and return -1.

Typical examples are llapi_fswap_layouts_grouplock() and llapi_layout_get_by_fd(). I would say the funnier one is llapi_open_by_fid() where llapi_search_mounts() return error code but llapi_open_by_fid() itself returns -1 as if the errno has been set.

Comments

[Andreas Dilger]

There was a long discussion about this in LU-3840. The proposal there was to set errno and return -1 to the caller for llapi_layout_* functions, but this doesn't help with existing functions that return -errno.

My thought is that it makes sense to update existing functions to both return -errno and also set errno internally. Callers can then either check rc < 0 and access errno, or continue to use the return code directly. This gives is a path to move toward a single style of error returns.

[Jinshan Xiong (Inactive)]

Hi Andreas, Which way do you prefer for the new APIs?

[Andreas Dilger]

The newer llapi_layout code is using -1 and errno.