Fix diskinfo race (#12857)

Fixes share info struct.

```
WARNING: DATA RACE
Read at 0x00c011780618 by goroutine 419:
  github.com/minio/minio/cmd.(*DiskMetrics).DecodeMsg()
      c:/gopath/src/github.com/minio/minio/cmd/storage-datatypes_gen.go:331 +0x247
  github.com/minio/minio/cmd.(*DiskInfo).DecodeMsg()
      c:/gopath/src/github.com/minio/minio/cmd/storage-datatypes_gen.go:76 +0x5ec
  github.com/tinylib/msgp/msgp.Decode()
      c:/gopath/pkg/mod/github.com/tinylib/msgp@v1.1.6-0.20210521143832-0becd170c402/msgp/read.go:105 +0x70
  github.com/minio/minio/cmd.(*storageRESTClient).DiskInfo.func1.1()
      c:/gopath/src/github.com/minio/minio/cmd/storage-rest-client.go:288 +0x235
  github.com/minio/minio/cmd.(*timedValue).Get()
      c:/gopath/src/github.com/minio/minio/cmd/utils.go:886 +0x77
  github.com/minio/minio/cmd.(*storageRESTClient).DiskInfo()
      c:/gopath/src/github.com/minio/minio/cmd/storage-rest-client.go:297 +0xf9
  github.com/minio/minio/cmd.getDiskInfos()
      c:/gopath/src/github.com/minio/minio/cmd/object-api-utils.go:962 +0x1a8
  github.com/minio/minio/cmd.(*erasureServerPools).getServerPoolsAvailableSpace.func1()
      c:/gopath/src/github.com/minio/minio/cmd/erasure-server-pool.go:241 +0x27c
  github.com/minio/minio/internal/sync/errgroup.(*Group).Go.func1()
      c:/gopath/src/github.com/minio/minio/internal/sync/errgroup/errgroup.go:123 +0xd7

Previous write at 0x00c011780618 by goroutine 423:
  github.com/minio/minio/cmd.(*DiskMetrics).DecodeMsg()
      c:/gopath/src/github.com/minio/minio/cmd/storage-datatypes_gen.go:332 +0x6e4
  github.com/minio/minio/cmd.(*DiskInfo).DecodeMsg()
      c:/gopath/src/github.com/minio/minio/cmd/storage-datatypes_gen.go:76 +0x5ec
  github.com/tinylib/msgp/msgp.Decode()
      c:/gopath/pkg/mod/github.com/tinylib/msgp@v1.1.6-0.20210521143832-0becd170c402/msgp/read.go:105 +0x70
  github.com/minio/minio/cmd.(*storageRESTClient).DiskInfo.func1.1()
      c:/gopath/src/github.com/minio/minio/cmd/storage-rest-client.go:288 +0x235
  github.com/minio/minio/cmd.(*timedValue).Get()
      c:/gopath/src/github.com/minio/minio/cmd/utils.go:886 +0x77
  github.com/minio/minio/cmd.(*storageRESTClient).DiskInfo()
      c:/gopath/src/github.com/minio/minio/cmd/storage-rest-client.go:297 +0xf9
  github.com/minio/minio/cmd.getDiskInfos()
      c:/gopath/src/github.com/minio/minio/cmd/object-api-utils.go:962 +0x1a8
  github.com/minio/minio/cmd.(*erasureServerPools).getServerPoolsAvailableSpace.func1()
      c:/gopath/src/github.com/minio/minio/cmd/erasure-server-pool.go:241 +0x27c
  github.com/minio/minio/internal/sync/errgroup.(*Group).Go.func1()
      c:/gopath/src/github.com/minio/minio/internal/sync/errgroup/errgroup.go:123 +0xd7
```

buildscripts/verify-healing.sh

@@ -14,8 +14,6 @@ WORK_DIR="$PWD/.verify-$RANDOM"
 MINIO_CONFIG_DIR="$WORK_DIR/.minio"
 MINIO=( "$PWD/minio" --config-dir "$MINIO_CONFIG_DIR" server )
 
-export GOGC=25
-
 function start_minio_3_node() {
     export MINIO_ROOT_USER=minio
     export MINIO_ROOT_PASSWORD=minio123
@@ -67,7 +65,7 @@ function start_minio_3_node() {
 
 
 function check_online() {
-    if grep -q 'Unable to initialize sub-systems' ${WORK_DIR}/dist-minio-*.log; then
+    if grep -q 'Unable to initialize' ${WORK_DIR}/dist-minio-*.log; then
         echo "1"
     fi
 }
@@ -88,22 +86,24 @@ function __init__()
 }
 
 function perform_test() {
-    start_minio_3_node 60
+    start_minio_3_node 120
 
     echo "Testing Distributed Erasure setup healing of drives"
     echo "Remove the contents of the disks belonging to '${1}' erasure set"
 
+    set -x
+
     rm -rf ${WORK_DIR}/${1}/*/
 
-    start_minio_3_node 60
+    start_minio_3_node 200
 
     rv=$(check_online)
     if [ "$rv" == "1" ]; then
-        pkill -9 minio
         for i in $(seq 1 3); do
             echo "server$i log:"
             cat "${WORK_DIR}/dist-minio-server$i.log"
         done
+        pkill -9 minio
         echo "FAILED"
         purge "$WORK_DIR"
         exit 1

cmd/prepare-storage.go

@@ -328,7 +328,13 @@ func waitForFormatErasure(firstDisk bool, endpoints Endpoints, poolCount, setCou
 					continue
 				case errErasureReadQuorum:
 					// no quorum available continue to wait for minimum number of servers.
-					logger.Info("Waiting for a minimum of %d disks to come online (elapsed %s)\n", len(endpoints)/2, getElapsedTime())
+					logger.Info("Waiting for a minimum of %d disks to come online (elapsed %s)\n",
+						len(endpoints)/2, getElapsedTime())
+					continue
+				case errErasureWriteQuorum:
+					// no quorum available continue to wait for minimum number of servers.
+					logger.Info("Waiting for a minimum of %d disks to come online (elapsed %s)\n",
+						(len(endpoints)/2)+1, getElapsedTime())
 					continue
 				case errErasureV3ThisEmpty:
 					// need to wait for this error to be healed, so continue.

cmd/storage-rest-client.go

@@ -265,6 +265,24 @@ func (client *storageRESTClient) SetDiskID(id string) {
 	client.diskID = id
 }
 
+func (client *storageRESTClient) diskInfo() (interface{}, error) {
+	var info DiskInfo
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	respBody, err := client.call(ctx, storageRESTMethodDiskInfo, nil, nil, -1)
+	if err != nil {
+		return info, err
+	}
+	defer xhttp.DrainBody(respBody)
+	if err = msgp.Decode(respBody, &info); err != nil {
+		return info, err
+	}
+	if info.Error != "" {
+		return info, toStorageErr(errors.New(info.Error))
+	}
+	return info, nil
+}
+
 // DiskInfo - fetch disk information for a remote disk.
 func (client *storageRESTClient) DiskInfo(ctx context.Context) (info DiskInfo, err error) {
 	if !client.IsOnline() {
@@ -277,22 +295,7 @@ func (client *storageRESTClient) DiskInfo(ctx context.Context) (info DiskInfo, e
 	}
 	client.diskInfoCache.Once.Do(func() {
 		client.diskInfoCache.TTL = time.Second
-		client.diskInfoCache.Update = func() (interface{}, error) {
+		client.diskInfoCache.Update = client.diskInfo
-			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
-			defer cancel()
-			respBody, err := client.call(ctx, storageRESTMethodDiskInfo, nil, nil, -1)
-			if err != nil {
-				return info, err
-			}
-			defer xhttp.DrainBody(respBody)
-			if err = msgp.Decode(respBody, &info); err != nil {
-				return info, err
-			}
-			if info.Error != "" {
-				return info, toStorageErr(errors.New(info.Error))
-			}
-			return info, nil
-		}
 	})
 	val, err := client.diskInfoCache.Get()
 	if err == nil {