mirror of
https://github.com/minio/minio.git
synced 2025-10-31 00:01:27 +01:00
69 lines
2.6 KiB
Go
69 lines
2.6 KiB
Go
//go:build windows || openbsd || plan9
|
|
|
|
// Copyright (c) 2015-2023 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 disk
|
|
|
|
import (
|
|
"os"
|
|
)
|
|
|
|
// ODirectPlatform indicates if the platform supports O_DIRECT
|
|
const ODirectPlatform = false
|
|
|
|
// OpenBSD, Windows, and illumos do not support O_DIRECT.
|
|
// On Windows there is no documentation on disabling O_DIRECT.
|
|
// For these systems we do not attempt to build the 'directio' dependency since
|
|
// the O_DIRECT symbol may not be exposed resulting in a failed build.
|
|
//
|
|
//
|
|
// On illumos an explicit O_DIRECT flag is not necessary for two primary
|
|
// reasons. Note that ZFS is effectively the default filesystem on illumos
|
|
// systems.
|
|
//
|
|
// One benefit of using DirectIO on Linux is that the page cache will not be
|
|
// polluted with single-access data. The ZFS read cache (ARC) is scan-resistant
|
|
// so there is no risk of polluting the entire cache with data accessed once.
|
|
// Another goal of DirectIO is to minimize the mutation of data by the kernel
|
|
// before issuing IO to underlying devices. ZFS users often enable features like
|
|
// compression and checksumming which currently necessitates mutating data in
|
|
// the kernel.
|
|
//
|
|
// DirectIO semantics for a filesystem like ZFS would be quite different than
|
|
// the semantics on filesystems like XFS, and these semantics are not
|
|
// implemented at this time.
|
|
// For more information on why typical DirectIO semantics do not apply to ZFS
|
|
// see this ZFS-on-Linux commit message:
|
|
// https://github.com/openzfs/zfs/commit/a584ef26053065f486d46a7335bea222cb03eeea
|
|
|
|
// OpenFileDirectIO wrapper around os.OpenFile nothing special
|
|
func OpenFileDirectIO(filePath string, flag int, perm os.FileMode) (*os.File, error) {
|
|
return os.OpenFile(filePath, flag, perm)
|
|
}
|
|
|
|
// DisableDirectIO is a no-op
|
|
func DisableDirectIO(f *os.File) error {
|
|
return nil
|
|
}
|
|
|
|
// AlignedBlock simply returns an unaligned buffer
|
|
// for systems that do not support DirectIO.
|
|
func AlignedBlock(blockSize int) []byte {
|
|
return make([]byte, blockSize)
|
|
}
|