Refactor the multi-host salt install page.

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

diff --git a/services/keepstore/volume.go b/services/keepstore/volume.go
index 9bfc6ca3e5191d2953ceac75f915a07cab19c69f..c3b8cd6283e0311c93fcc914ebd3b370045cfa0f 100644 (file)
--- a/services/keepstore/volume.go
+++ b/services/keepstore/volume.go
@@ -2,7 +2,7 @@
 //
 // SPDX-License-Identifier: AGPL-3.0
 
-package main
+package keepstore
 
 import (
        "context"
@@ -344,11 +344,11 @@ func makeRRVolumeManager(logger logrus.FieldLogger, cluster *arvados.Cluster, my
                        vm.writables = append(vm.writables, mnt)
                }
        }
-       // pri(i): return highest priority of any storage class
-       // offered by vm.readables[i]
-       pri := func(i int) int {
+       // pri(mnt): return highest priority of any storage class
+       // offered by mnt
+       pri := func(mnt *VolumeMount) int {
                any, best := false, 0
-               for class := range vm.readables[i].KeepMount.StorageClasses {
+               for class := range mnt.KeepMount.StorageClasses {
                        if p := cluster.StorageClasses[class].Priority; !any || best < p {
                                best = p
                                any = true
@@ -356,14 +356,23 @@ func makeRRVolumeManager(logger logrus.FieldLogger, cluster *arvados.Cluster, my
                }
                return best
        }
-       // sort vm.readables, first by highest priority of any offered
+       // less(a,b): sort first by highest priority of any offered
        // storage class (highest->lowest), then by volume UUID
-       sort.Slice(vm.readables, func(i, j int) bool {
-               if pi, pj := pri(i), pri(j); pi != pj {
-                       return pi > pj
+       less := func(a, b *VolumeMount) bool {
+               if pa, pb := pri(a), pri(b); pa != pb {
+                       return pa > pb
                } else {
-                       return vm.readables[i].KeepMount.UUID < vm.readables[j].KeepMount.UUID
+                       return a.KeepMount.UUID < b.KeepMount.UUID
                }
+       }
+       sort.Slice(vm.readables, func(i, j int) bool {
+               return less(vm.readables[i], vm.readables[j])
+       })
+       sort.Slice(vm.writables, func(i, j int) bool {
+               return less(vm.writables[i], vm.writables[j])
+       })
+       sort.Slice(vm.mounts, func(i, j int) bool {
+               return less(vm.mounts[i], vm.mounts[j])
        })
        return vm, nil
 }
@@ -384,18 +393,22 @@ func (vm *RRVolumeManager) AllReadable() []*VolumeMount {
        return vm.readables
 }
 
-// AllWritable returns an array of all writable volumes
+// AllWritable returns writable volumes, sorted by priority/uuid. Used
+// by CompareAndTouch to ensure higher-priority volumes are checked
+// first.
 func (vm *RRVolumeManager) AllWritable() []*VolumeMount {
        return vm.writables
 }
 
-// NextWritable returns the next writable
-func (vm *RRVolumeManager) NextWritable() *VolumeMount {
+// NextWritable returns writable volumes, rotated by vm.counter so
+// each volume gets a turn to be first. Used by PutBlock to distribute
+// new data across available volumes.
+func (vm *RRVolumeManager) NextWritable() []*VolumeMount {
        if len(vm.writables) == 0 {
                return nil
        }
-       i := atomic.AddUint32(&vm.counter, 1)
-       return vm.writables[i%uint32(len(vm.writables))]
+       offset := (int(atomic.AddUint32(&vm.counter, 1)) - 1) % len(vm.writables)
+       return append(append([]*VolumeMount(nil), vm.writables[offset:]...), vm.writables[:offset]...)
 }
 
 // VolumeStats returns an ioStats for the given volume.