mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-30 00:40:21 +00:00
9eaa55506f
This commit updates controller-runtime to v0.9.2 and makes changes in persistentvolume.go to add context to various functions and function calls made here instead of context.TODO(). Signed-off-by: Rakshith R <rar@redhat.com>
99 lines
2.9 KiB
Go
99 lines
2.9 KiB
Go
/*
|
|
Copyright 2017 The Kubernetes Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package io
|
|
|
|
import (
|
|
"bytes"
|
|
"errors"
|
|
"fmt"
|
|
"io"
|
|
"io/ioutil"
|
|
)
|
|
|
|
// ErrLimitReached means that the read limit is reached.
|
|
var ErrLimitReached = errors.New("the read limit is reached")
|
|
|
|
// ConsistentRead repeatedly reads a file until it gets the same content twice.
|
|
// This is useful when reading files in /proc that are larger than page size
|
|
// and kernel may modify them between individual read() syscalls.
|
|
// It returns InconsistentReadError when it cannot get a consistent read in
|
|
// given nr. of attempts. Caller should retry, kernel is probably under heavy
|
|
// mount/unmount load.
|
|
func ConsistentRead(filename string, attempts int) ([]byte, error) {
|
|
return consistentReadSync(filename, attempts, nil)
|
|
}
|
|
|
|
// consistentReadSync is the main functionality of ConsistentRead but
|
|
// introduces a sync callback that can be used by the tests to mutate the file
|
|
// from which the test data is being read
|
|
func consistentReadSync(filename string, attempts int, sync func(int)) ([]byte, error) {
|
|
oldContent, err := ioutil.ReadFile(filename)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
for i := 0; i < attempts; i++ {
|
|
if sync != nil {
|
|
sync(i)
|
|
}
|
|
newContent, err := ioutil.ReadFile(filename)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if bytes.Compare(oldContent, newContent) == 0 {
|
|
return newContent, nil
|
|
}
|
|
// Files are different, continue reading
|
|
oldContent = newContent
|
|
}
|
|
return nil, InconsistentReadError{filename, attempts}
|
|
}
|
|
|
|
// InconsistentReadError is returned from ConsistentRead when it cannot get
|
|
// a consistent read in given nr. of attempts. Caller should retry, kernel is
|
|
// probably under heavy mount/unmount load.
|
|
type InconsistentReadError struct {
|
|
filename string
|
|
attempts int
|
|
}
|
|
|
|
func (i InconsistentReadError) Error() string {
|
|
return fmt.Sprintf("could not get consistent content of %s after %d attempts", i.filename, i.attempts)
|
|
}
|
|
|
|
var _ error = InconsistentReadError{}
|
|
|
|
func IsInconsistentReadError(err error) bool {
|
|
if _, ok := err.(InconsistentReadError); ok {
|
|
return true
|
|
}
|
|
return false
|
|
}
|
|
|
|
// ReadAtMost reads up to `limit` bytes from `r`, and reports an error
|
|
// when `limit` bytes are read.
|
|
func ReadAtMost(r io.Reader, limit int64) ([]byte, error) {
|
|
limitedReader := &io.LimitedReader{R: r, N: limit}
|
|
data, err := ioutil.ReadAll(limitedReader)
|
|
if err != nil {
|
|
return data, err
|
|
}
|
|
if limitedReader.N <= 0 {
|
|
return data, ErrLimitReached
|
|
}
|
|
return data, nil
|
|
}
|