[audit][cache] create_volume: self-declared 'really bad code' with a function-local static that breaks reinitialization

Severity: medium · Category: logic-bug
Location: src/iocore/cache/CacheProcessor.cc:1335

What's wrong

create_volume() opens with the maintainer note 'This is some really bad code, and needs to be rewritten!' and immediately uses 'static int curr_vol = 0' flagged '// FIXME: this will not reinitialize correctly'. Because the round-robin cursor persists across invocations/reconfigurations, volume placement after a cache volume reconfiguration depends on stale state from the previous configuration pass - a latent correctness bug in cache stripe assignment, in addition to being non-reentrant.

Evidence

// This is some really bad code, and needs to be rewritten!
int
create_volume(int volume_number, off_t size_in_blocks, CacheType scheme, CacheVol *cp)
{
  static int curr_vol       = 0; // FIXME: this will not reinitialize correctly

Suggested fix

Move curr_vol into the configuration-pass context (e.g. a parameter or a member of the object driving volume creation) so each (re)configuration starts from a defined cursor, then schedule the promised rewrite.

Filed from an automated multi-lens codebase audit. Full report: CODEBASE_AUDIT.md / audit-report.html on branch claude/codebase-audit-review-9nw7vz.

Start with create_volume() at src/iocore/cache/CacheProcessor.cc:1335 and read CODEBASE_AUDIT.md for the audit context. Trace the configuration-pass context that drives volume creation and determine how the static cursor is used across reconfigurations. Done means the cursor has defined state for each configuration pass and the cache stripe assignment no longer depends on prior configuration state.