minio/cmd/erasure-common.go

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// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"context"
"sync"
"github.com/minio/minio/internal/sync/errgroup"
)
func (er erasureObjects) getLocalDisks() (localDisks []StorageAPI) {
disks := er.getDisks()
for _, disk := range disks {
if disk != nil && disk.IsLocal() {
localDisks = append(localDisks, disk)
}
}
return localDisks
}
func (er erasureObjects) getLoadBalancedLocalDisks() (newDisks []StorageAPI) {
disks := er.getDisks()
// Based on the random shuffling return back randomized disks.
for _, i := range hashOrder(UTCNow().String(), len(disks)) {
if disks[i-1] != nil && disks[i-1].IsLocal() {
if disks[i-1].Healing() == nil && disks[i-1].IsOnline() {
newDisks = append(newDisks, disks[i-1])
}
}
}
return newDisks
}
// getLoadBalancedDisks - fetches load balanced (sufficiently randomized) disk slice.
// ensures to skip disks if they are not healing and online.
func (er erasureObjects) getLoadBalancedDisks(optimized bool) []StorageAPI {
disks := er.getDisks()
if !optimized {
var newDisks []StorageAPI
for _, i := range hashOrder(UTCNow().String(), len(disks)) {
newDisks = append(newDisks, disks[i-1])
}
return newDisks
}
var wg sync.WaitGroup
var mu sync.Mutex
var newDisks = map[uint64][]StorageAPI{}
// Based on the random shuffling return back randomized disks.
for _, i := range hashOrder(UTCNow().String(), len(disks)) {
i := i
wg.Add(1)
go func() {
defer wg.Done()
if disks[i-1] == nil {
return
}
di, err := disks[i-1].DiskInfo(context.Background())
if err != nil || di.Healing {
// - Do not consume disks which are not reachable
// unformatted or simply not accessible for some reason.
//
// - Do not consume disks which are being healed
//
// - Future: skip busy disks
return
}
mu.Lock()
// Capture disks usage wise upto resolution of MiB
newDisks[di.Used/1024/1024] = append(newDisks[di.Used/1024/1024], disks[i-1])
mu.Unlock()
}()
}
wg.Wait()
var max uint64
for k := range newDisks {
if k > max {
max = k
}
}
// Return disks which have maximum disk usage common.
return newDisks[max]
}
// This function does the following check, suppose
// object is "a/b/c/d", stat makes sure that objects
// - "a/b/c"
// - "a/b"
// - "a"
// do not exist on the namespace.
func (er erasureObjects) parentDirIsObject(ctx context.Context, bucket, parent string) bool {
storageDisks := er.getDisks()
g := errgroup.WithNErrs(len(storageDisks))
for index := range storageDisks {
index := index
g.Go(func() error {
if storageDisks[index] == nil {
return errDiskNotFound
}
// Check if 'prefix' is an object on this 'disk', else continue the check the next disk
return storageDisks[index].CheckFile(ctx, bucket, parent)
}, index)
}
// NOTE: Observe we are not trying to read `xl.meta` and figure out the actual
// quorum intentionally, but rely on the default case scenario. Actual quorum
// verification will happen by top layer by using getObjectInfo() and will be
// ignored if necessary.
readQuorum := getReadQuorum(len(storageDisks))
return reduceReadQuorumErrs(ctx, g.Wait(), objectOpIgnoredErrs, readQuorum) == nil
}