* ec: don't index ev.Shards[0] when the last shard was unmounted
* ec: skip a runtime emptied before the scrub merge reads its shards
FindAllEcVolumes releases each location lock before MergeEcRuntimes runs,
so an unmount can leave a merged runtime with no shards and the width
scan indexed Shards[-1].
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* ec: treat a scrub merge with no shard left as a vanished volume
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* ec: read Shards once in ShardSize so a concurrent unmount cannot empty it
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* ec: read each runtime's Shards once in the scrub merge
The vanished check and the slot construction read Shards separately, so
an unmount between them produced a non-nil view with no shards.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
* ec: anchor the scrub merge on a generation that still holds shards
An unmount can empty the newest runtime while an older one keeps its
shards, which left a merged view anchored on the emptied generation with
no slots and the holder reported as skipped.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---------
Co-authored-by: Mansur Akhmadi <10739460+mansur-akhmadi@users.noreply.github.com>
Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
