Nick Craig-Wood
e006d7c13f
The VFS is shared between users with the same remote and options, for example two mounts created over the rc, or a mount and an NFS server. Each node has a single Sys() slot which mount, mount2 and serve nfs all used to attach their per-node data. With a shared VFS the users overwrote each other's data: at best churning the cached FUSE nodes, and since the slot was an atomic.Value, panicking with "store of inconsistently typed value" as soon as two users stored different types on the same node. This change gives each node auxiliary values keyed by owner, set with SetAux and read with Aux, so each user of the VFS has an independent slot. The mounts now cache their FUSE nodes under their own key, leaving Sys - which is read through the os.FileInfo interface - reserved for users like serve nfs which need to control what that returns. Nodes with nothing attached use less memory than before (one pointer instead of an atomic.Value) and reads remain lock free. Bug discovered while thinking about #9617
74 lines
1.4 KiB
Go
74 lines
1.4 KiB
Go
package vfs
|
|
|
|
import (
|
|
"fmt"
|
|
"sync"
|
|
"testing"
|
|
|
|
"github.com/stretchr/testify/assert"
|
|
)
|
|
|
|
func TestAux(t *testing.T) {
|
|
var a aux
|
|
owner1, owner2 := new(int), new(int)
|
|
|
|
// Nothing attached yet
|
|
assert.Nil(t, a.Aux(owner1))
|
|
assert.Nil(t, a.Sys())
|
|
|
|
// Values attached by different owners are independent even if
|
|
// they have different types
|
|
a.SetAux(owner1, "potato")
|
|
a.SetAux(owner2, 2)
|
|
assert.Equal(t, "potato", a.Aux(owner1))
|
|
assert.Equal(t, 2, a.Aux(owner2))
|
|
|
|
// Replace a value
|
|
a.SetAux(owner1, "sausage")
|
|
assert.Equal(t, "sausage", a.Aux(owner1))
|
|
|
|
// Remove a value
|
|
a.SetAux(owner1, nil)
|
|
assert.Nil(t, a.Aux(owner1))
|
|
assert.Equal(t, 2, a.Aux(owner2))
|
|
|
|
// Sys is independent of the other owners
|
|
assert.Nil(t, a.Sys())
|
|
a.SetSys(42)
|
|
assert.Equal(t, 42, a.Sys())
|
|
assert.Equal(t, 2, a.Aux(owner2))
|
|
|
|
// Changing the type of the value stored must not panic
|
|
a.SetSys("42")
|
|
assert.Equal(t, "42", a.Sys())
|
|
|
|
// Remove the remaining values
|
|
a.SetSys(nil)
|
|
a.SetAux(owner2, nil)
|
|
assert.Nil(t, a.entries.Load())
|
|
}
|
|
|
|
func TestAuxConcurrent(t *testing.T) {
|
|
const (
|
|
owners = 4
|
|
iterations = 100
|
|
)
|
|
var (
|
|
a aux
|
|
wg sync.WaitGroup
|
|
)
|
|
for i := range owners {
|
|
wg.Add(1)
|
|
go func() {
|
|
defer wg.Done()
|
|
owner := &i
|
|
for j := range iterations {
|
|
value := fmt.Sprintf("%d-%d", i, j)
|
|
a.SetAux(owner, value)
|
|
assert.Equal(t, value, a.Aux(owner))
|
|
}
|
|
}()
|
|
}
|
|
wg.Wait()
|
|
}
|