The background tier free-version recovery walk pinned a hardcoded 60s
total wall-clock timeout that overrides every operator knob, so any
bucket whose healthy full walk exceeds 60s fails forever; the failed
run's duration was also subtracted from the next 60s tick, restarting
the walk immediately and pinning CPU and disk I/O.
- Drop the total wall-clock budget on the recovery walk
(walkdir_timeout: Duration::ZERO) and inherit the operator-tunable
drive stall budget (RUSTFS_DRIVE_WALKDIR_STALL_TIMEOUT_SECS) for
per-call progress, so hung disks still fail fast.
- Back off failed runs from completion time: 60s doubling to a 600s
cap, reset on success; never subtract the failed run's duration.
- Add RUSTFS_TIER_FREE_VERSION_RECOVERY_ENABLED (default true) to opt
out of the recovery worker on deployments with no remote tiers;
invalid values warn and fail open.
Fixes#5130
Co-authored-by: claude <[email protected]>
