Problem

lctl get_param -n -y prints the parameter name for a multi-line value. The -n option must print only the value. For a single-line value, -n -y prints only the value, as expected.

Environment

• master, 2.17.0 and later.
• The defect started with commit 5768bf35fd ("LU-18502 utils: Support YAML for get_param parameter names", https://review.whamcloud.com/58113).

Reproduction

1. On the MGS, create a nodemap with 2 idmaps: lctl nodemap_add c0, then lctl nodemap_add_idmap --name c0 --idtype uid --idmap 1003:11000 and lctl nodemap_add_idmap --name c0 --idtype gid --idmap 1003:11000.
2. Run lctl get_param -n -y nodemap.c0.idmap.

Expected output is the value only:

[
 { idtype: uid, client_id: 1003, fs_id: 11000 },
 { idtype: gid, client_id: 1003, fs_id: 11000 }
]

Actual output starts with the name:

nodemap.c0.idmap: [
 { idtype: uid, client_id: 1003, fs_id: 11000 },
 { idtype: gid, client_id: 1003, fs_id: 11000 }
]

This result comes from a source review. We did not run the reproduction.

Analysis

In print_param_internal() in lustre/utils/lustre_param.c, the multi-line branch runs when po_yaml or po_header is set. That branch prints lpf_name on the first line and does not check po_show_name. The single-line branch (the else branch) prints the name only when po_show_name is set.

Before 5768bf35fd, only po_header selected the multi-line branch. A -n -y request went to the single-line branch, so it printed only the value.

The AI review of https://review.whamcloud.com/69687 found this defect. 69687 indents the lines of a multi-line value for -y, so with -n the output now also has the indent.

Proposed fix

In the multi-line branch, print the name and the separator only when po_show_name is set. When po_show_name is clear, print the value without the name and without the extra indent. Add a -n -y case for a multi-line parameter to sanity-sec test_25c.