applyOptions consumes the "path" option into vol.Path rather than leaving
it in vol.Options, but restoreState rebuilt the options with only fs and
type. The explicit path was therefore dropped when the plugin restarted,
and since fsString is rebuilt from those options the volume was remounted
at the root of the remote instead of at its subpath.
Before this change a volume created with type + path lost its path
completely, and one created with remote + path silently fell back to the
path of the connection string. With a backend whose credentials are
scoped to the subpath the restored mount then failed every operation
rather than serving the wrong directory.
Feed the persisted path back like fs and type, so applyOptions applies
the same precedence on restore that it applies when the volume is
first created.
Fixes#9853
phatlcandNick Craig-Wood
9ac29e3b35