Hung datastore query

[Stebalien]

Version information:

go-ipfs version: 0.4.21-dev-
Repo version: 7
System version: amd64/linux
Golang version: go1.12.4

Type:

• bug

Description:

I noticed a hung datastore query that we should probaly look into:

goroutine 826 [select, 178 minutes]:
github.com/ipfs/go-ds-flatfs.(*Datastore).walk(0xc0004247e0, 0xc000528da0, 0x14, 0xc0004c6e00, 0x0, 0x0)
        /go/pkg/mod/github.com/ipfs/[email protected]/flatfs.go:1032 +0x35c
github.com/ipfs/go-ds-flatfs.(*Datastore).walkTopLevel(0xc0004247e0, 0xc000428520, 0x11, 0xc0004c6e00, 0x0, 0x0)
        /go/pkg/mod/github.com/ipfs/[email protected]/flatfs.go:690 +0x1a2
github.com/ipfs/go-ds-flatfs.(*Datastore).Query.func1(0x1a706c0, 0xc0003113e0)
        /go/pkg/mod/github.com/ipfs/[email protected]/flatfs.go:661 +0x5f
github.com/jbenet/goprocess.(*process).Go.func1(0xc0005308a0, 0xc0003113e0, 0xc000311440)
        /go/pkg/mod/github.com/jbenet/[email protected]/impl-mutex.go:112 +0x3c
created by github.com/jbenet/goprocess.(*process).Go
/go/pkg/mod/github.com/jbenet/[email protected]/impl-mutex.go:111 +0x1f7

Full trace: https://gist.github.com/Stebalien/8683bd8c0f79862348e6d3ca04f0993b
Deps: https://gist.github.com/Stebalien/1bea0391eec09889a3bb3b31643b8e4b