Critical fix: FilerClient now accepts []ServerAddress instead of single address
- Prevents mount failure when first filer is down (regression fix)
- Implements automatic failover to remaining filers
- Uses round-robin with atomic index tracking (same pattern as WFS.WithFilerClient)
- Retries all configured filers before giving up
- Updates successful filer index for future requests
Changes:
- NewFilerClient([]pb.ServerAddress, ...) instead of (pb.ServerAddress, ...)
- filerVolumeProvider references FilerClient for failover access
- LookupVolumeIds tries all filers with util.Retry pattern
- Mount passes all option.FilerAddresses for HA
- S3 wraps single filer in slice for API consistency
This restores the high availability that existed in the old implementation
where mount would automatically failover between configured filers.
chrislu