d00ff3c453
This PR also removes #13312 to ensure that we can use a better mechanism to handle page-cache, using O_DIRECT even for Range GETs.
132 lines
3.1 KiB
Go
132 lines
3.1 KiB
Go
// Copyright (c) 2015-2021 MinIO, Inc.
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//
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// This file is part of MinIO Object Storage stack
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package ioutil
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import (
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"errors"
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"io"
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"os"
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"sync"
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"syscall"
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"github.com/dustin/go-humanize"
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"github.com/minio/minio/internal/disk"
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)
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// ODirectReader - to support O_DIRECT reads for erasure backends.
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type ODirectReader struct {
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File *os.File
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SmallFile bool
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err error
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buf []byte
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bufp *[]byte
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seenRead bool
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}
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// Block sizes constant.
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const (
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BlockSizeSmall = 128 * humanize.KiByte // Default r/w block size for smaller objects.
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BlockSizeLarge = 2 * humanize.MiByte // Default r/w block size for larger objects.
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BlockSizeReallyLarge = 4 * humanize.MiByte // Default write block size for objects per shard >= 64MiB
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)
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// O_DIRECT aligned sync.Pool's
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var (
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ODirectPoolXLarge = sync.Pool{
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New: func() interface{} {
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b := disk.AlignedBlock(BlockSizeReallyLarge)
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return &b
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},
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}
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ODirectPoolLarge = sync.Pool{
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New: func() interface{} {
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b := disk.AlignedBlock(BlockSizeLarge)
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return &b
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},
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}
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ODirectPoolSmall = sync.Pool{
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New: func() interface{} {
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b := disk.AlignedBlock(BlockSizeSmall)
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return &b
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},
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}
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)
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// Invalid argument, unsupported flags such as O_DIRECT
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func isSysErrInvalidArg(err error) bool {
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return errors.Is(err, syscall.EINVAL)
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}
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// Read - Implements Reader interface.
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func (o *ODirectReader) Read(buf []byte) (n int, err error) {
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if o.err != nil && (len(o.buf) == 0 || !o.seenRead) {
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return 0, o.err
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}
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if o.buf == nil {
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if o.SmallFile {
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o.bufp = ODirectPoolSmall.Get().(*[]byte)
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} else {
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o.bufp = ODirectPoolLarge.Get().(*[]byte)
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}
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}
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if !o.seenRead {
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o.buf = *o.bufp
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n, err = o.File.Read(o.buf)
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if err != nil && err != io.EOF {
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if isSysErrInvalidArg(err) {
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if err = disk.DisableDirectIO(o.File); err != nil {
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o.err = err
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return n, err
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}
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n, err = o.File.Read(o.buf)
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}
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if err != nil && err != io.EOF {
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o.err = err
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return n, err
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}
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}
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if n == 0 {
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// err is likely io.EOF
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o.err = err
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return n, err
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}
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o.err = err
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o.buf = o.buf[:n]
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o.seenRead = true
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}
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if len(buf) >= len(o.buf) {
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n = copy(buf, o.buf)
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o.seenRead = false
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return n, o.err
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}
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n = copy(buf, o.buf)
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o.buf = o.buf[n:]
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// There is more left in buffer, do not return any EOF yet.
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return n, nil
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}
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// Close - Release the buffer and close the file.
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func (o *ODirectReader) Close() error {
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if o.SmallFile {
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ODirectPoolSmall.Put(o.bufp)
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} else {
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ODirectPoolLarge.Put(o.bufp)
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}
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return o.File.Close()
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}
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