[LU-13335] add name lookup for project IDs

Related — Sat, 9 Dec 2023 00:20:07 +0000

It would be useful to allow names to be mapped to projid numbers using the /etc/projid file (projid.5), as is used by the XFS quota utility (xfs_quota.8):

usera:1
userc:3

There should be a new function struct ll_project *llapi_getprjname(const char *name) function that is called by lfs and lctl to read the /etc/projid file and lookup the name and return the projid, while struct ll_project *llapi_getprjid(__u32 prjid) would lookup the numeric project ID and return the name:

struct ll_project {
        __u32 lp_projid;
        char *lp_name;
};

Returning the struct instead of a single value (name or prjid) allows expanding this interface in the future (e.g. to list which users are allowed to use/change the group, passwords for the group, etc. as with getgrnam(), getgrgid(), getpwnam(), getpwuid()).

It isn't very clear what benefit the /etc/projects file (projects.5) provides, so I'm not yet sure whether we need to implement support for this or not.

Whamcloud Community JIRA

[LU-13335] add name lookup for project IDs