Merge branch '8784-dir-listings'

[arvados.git] / services / keepstore / volume.go

diff --git a/services/keepstore/volume.go b/services/keepstore/volume.go
index 778f27fcde87cbc324a246aec571b3fe7a5c2b8a..69802abdd1b5c4e22422293331d6cb0eec371896 100644 (file)
--- a/services/keepstore/volume.go
+++ b/services/keepstore/volume.go
@@ -1,8 +1,15 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: AGPL-3.0
+
 package main
 
 import (
        "context"
+       "crypto/rand"
+       "fmt"
        "io"
+       "math/big"
        "sync/atomic"
        "time"
 )
@@ -229,6 +236,10 @@ type Volume interface {
        // EmptyTrash looks for trashed blocks that exceeded TrashLifetime
        // and deletes them from the volume.
        EmptyTrash()
+
+       // Return a globally unique ID of the underlying storage
+       // device if possible, otherwise "".
+       DeviceID() string
 }
 
 // A VolumeWithExamples provides example configs to display in the
@@ -241,6 +252,14 @@ type VolumeWithExamples interface {
 // A VolumeManager tells callers which volumes can read, which volumes
 // can write, and on which volume the next write should be attempted.
 type VolumeManager interface {
+       // Mounts returns all mounts (volume attachments).
+       Mounts() []*VolumeMount
+
+       // Lookup returns the volume under the given mount
+       // UUID. Returns nil if the mount does not exist. If
+       // write==true, returns nil if the volume is not writable.
+       Lookup(uuid string, write bool) Volume
+
        // AllReadable returns all volumes.
        AllReadable() []Volume
 
@@ -263,10 +282,37 @@ type VolumeManager interface {
        Close()
 }
 
+// A VolumeMount is an attachment of a Volume to a VolumeManager.
+type VolumeMount struct {
+       UUID        string
+       DeviceID    string
+       ReadOnly    bool
+       Replication int
+       Tier        int
+       volume      Volume
+}
+
+// Generate a UUID the way API server would for a "KeepVolumeMount"
+// object.
+func (*VolumeMount) generateUUID() string {
+       var max big.Int
+       _, ok := max.SetString("zzzzzzzzzzzzzzz", 36)
+       if !ok {
+               panic("big.Int parse failed")
+       }
+       r, err := rand.Int(rand.Reader, &max)
+       if err != nil {
+               panic(err)
+       }
+       return fmt.Sprintf("zzzzz-ivpuk-%015s", r.Text(36))
+}
+
 // RRVolumeManager is a round-robin VolumeManager: the Nth call to
 // NextWritable returns the (N % len(writables))th writable Volume
 // (where writables are all Volumes v where v.Writable()==true).
 type RRVolumeManager struct {
+       mounts    []*VolumeMount
+       mountMap  map[string]*VolumeMount
        readables []Volume
        writables []Volume
        counter   uint32
@@ -278,8 +324,19 @@ func MakeRRVolumeManager(volumes []Volume) *RRVolumeManager {
        vm := &RRVolumeManager{
                iostats: make(map[Volume]*ioStats),
        }
+       vm.mountMap = make(map[string]*VolumeMount)
        for _, v := range volumes {
+               mnt := &VolumeMount{
+                       UUID:        (*VolumeMount)(nil).generateUUID(),
+                       DeviceID:    v.DeviceID(),
+                       ReadOnly:    !v.Writable(),
+                       Replication: v.Replication(),
+                       Tier:        1,
+                       volume:      v,
+               }
                vm.iostats[v] = &ioStats{}
+               vm.mounts = append(vm.mounts, mnt)
+               vm.mountMap[mnt.UUID] = mnt
                vm.readables = append(vm.readables, v)
                if v.Writable() {
                        vm.writables = append(vm.writables, v)
@@ -288,6 +345,18 @@ func MakeRRVolumeManager(volumes []Volume) *RRVolumeManager {
        return vm
 }
 
+func (vm *RRVolumeManager) Mounts() []*VolumeMount {
+       return vm.mounts
+}
+
+func (vm *RRVolumeManager) Lookup(uuid string, needWrite bool) Volume {
+       if mnt, ok := vm.mountMap[uuid]; ok && (!needWrite || !mnt.ReadOnly) {
+               return mnt.volume
+       } else {
+               return nil
+       }
+}
+
 // AllReadable returns an array of all readable volumes
 func (vm *RRVolumeManager) AllReadable() []Volume {
        return vm.readables