OCP C0 SMART log: JSON v2 output is missing form_factor and die_in_use_bad_nand_block fields (no case 6 block)

[krishna3554]

Summary

The OCP SMART / Health Information extended log (C0) JSON printer json_smart_extended_log_v2() is missing the case 6: field block that both the plain-text printer and the legacy JSON v1 printer emit. As a result, for drives reporting a C0 log_page_version >= 6, the fields form factor, die in use bad NAND block (raw) and die in use bad NAND block (normalized) are silently absent from the default -o json output while they are present in the default text output.

Static-analysis finding against current master; not executed here.

Location

• File: plugins/ocp/ocp-print-json.c
  • Function: json_smart_extended_log_v2() - the version-gating switch (smart_log_ver) around lines 471-475 goes straight from default: into case 5: with no case 6: section.
• Reference implementations that do print the block:
  • plugins/ocp/ocp-print-stdout.c, stdout_smart_extended_log(), case 6: at ~lines 181-187 (Form factor, Die in use badnandblock-Raw, Die in use badnandblock-Normal)
  • plugins/ocp/ocp-print-json.c, json_smart_extended_log_v1(), which contains the equivalent default: case 6: block (~lines 300-311)
• Field definitions: plugins/ocp/ocp-smart-extended-log.h (form_factor [223], die_in_use_bad_nand_block_raw[6] [363:358], die_in_use_bad_nand_block_normalized [365:364])

Problem

ocp_smart_add_log() passes nvme_args.output_format_ver (default = 2, see src/args.c) to ocp_smart_extended_log(), so JSON output normally goes through json_smart_extended_log_v2(). Inside that function the per-field gating switch is:

switch (smart_log_ver) {
case 0 ... 1:
    break;
default:
case 5:
    /* pcie errata, media dies, power ... */
    fallthrough;
...

There is no case 6: arm and no code anywhere else in the function that emits form_factor or either die_in_use_bad_nand_block_* value. The other two printers gate exactly these three fields behind case 6: (i.e. printed when the drive reports log page version >= 6), so v2 JSON diverges from them.

Trigger / Reproduction

Based on static analysis:

nvme ocp smart-add-log /dev/nvme0                 # text: prints Form factor + Die in use badnandblock
nvme ocp smart-add-log /dev/nvme0 -o json         # json v2 (default): the three keys are missing entirely

on a drive whose C0 log page reports log_page_version >= 6.

Expected Behavior

All three output paths (text, JSON v1, JSON v2) should expose the same spec-defined fields, subject to the same log_page_version gating. For version >= 6, JSON v2 should contain e.g. "form_factor", "die_in_use_bad_nand_block_raw" and "die_in_use_bad_nand_block_normalized".

Actual Behavior

JSON v2 output never contains those three keys, regardless of the drive's log page version, because no case 6: block exists in json_smart_extended_log_v2().

Impact

Scripts and monitoring systems consuming the default JSON output lose data that the human-readable output shows. The inconsistency is easy to miss because the legacy JSON v1 path (selected via an explicit older --output-format-version) still emits the fields under different key names ("Form factor", "Die use badnandblock raw", "Die use badnandblock normal").

Suggested Direction

Add the missing default:/case 6: section to json_smart_extended_log_v2(), mirroring stdout_smart_extended_log(): emit form_factor, int48_to_long(log->die_in_use_bad_nand_block_raw) and le16_to_cpu(log->die_in_use_bad_nand_block_normalized) ahead of the existing case 5: block, using snake_case keys consistent with the rest of v2.

Evidence

• plugins/ocp/ocp-print-json.c lines ~471-475: switch (smart_log_ver) in v2 jumps from default: directly to case 5:; grep confirms form_factor / die_in_use appear only inside json_smart_extended_log_v1() in this file.
• plugins/ocp/ocp-print-stdout.c ~line 181: case 6: prints the same three fields before falling through to case 5:.
• src/args.c: .output_format_ver = 2 is the default, making v2 the common path.

[igaw]

okay, care to send a patch?

[igaw]

#3981 has been merged