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mmap_span: Synchronize access to memory maps to avoid race when unmapping

This commit is contained in:
Matt Joiner 2018-01-06 16:39:52 +11:00
parent 6bcf2a58b2
commit 57fec52371
2 changed files with 16 additions and 6 deletions
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18
mmap_span/mmap_span.go
View File

@ -3,6 +3,7 @@ package mmap_span
import ( import (
"io" "io"
"log" "log"
"sync"
"github.com/edsrzf/mmap-go" "github.com/edsrzf/mmap-go"
) )
@ -16,6 +17,7 @@ func (s segment) Size() int64 {
} }
type MMapSpan struct { type MMapSpan struct {
mu sync.RWMutex
span span
} }
@ -23,7 +25,9 @@ func (ms *MMapSpan) Append(mmap mmap.MMap) {
ms.span = append(ms.span, segment{&mmap}) ms.span = append(ms.span, segment{&mmap})
} }
func (ms MMapSpan) Close() error { func (ms *MMapSpan) Close() error {
ms.mu.Lock()
defer ms.mu.Unlock()
for _, mMap := range ms.span { for _, mMap := range ms.span {
err := mMap.(segment).Unmap() err := mMap.(segment).Unmap()
if err != nil { if err != nil {
@ -33,14 +37,18 @@ func (ms MMapSpan) Close() error {
return nil return nil
} }
func (ms MMapSpan) Size() (ret int64) { func (ms *MMapSpan) Size() (ret int64) {
ms.mu.RLock()
defer ms.mu.RUnlock()
for _, seg := range ms.span { for _, seg := range ms.span {
ret += seg.Size() ret += seg.Size()
} }
return return
} }
func (ms MMapSpan) ReadAt(p []byte, off int64) (n int, err error) { func (ms *MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
ms.mu.RLock()
defer ms.mu.RUnlock()
ms.ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) { ms.ApplyTo(off, func(intervalOffset int64, interval sizer) (stop bool) {
_n := copy(p, (*interval.(segment).MMap)[intervalOffset:]) _n := copy(p, (*interval.(segment).MMap)[intervalOffset:])
p = p[_n:] p = p[_n:]
@ -53,7 +61,9 @@ func (ms MMapSpan) ReadAt(p []byte, off int64) (n int, err error) {
return return
} }
func (ms MMapSpan) WriteAt(p []byte, off int64) (n int, err error) { func (ms *MMapSpan) WriteAt(p []byte, off int64) (n int, err error) {
ms.mu.RLock()
defer ms.mu.RUnlock()
ms.ApplyTo(off, func(iOff int64, i sizer) (stop bool) { ms.ApplyTo(off, func(iOff int64, i sizer) (stop bool) {
mMap := i.(segment) mMap := i.(segment)
_n := copy((*mMap.MMap)[iOff:], p) _n := copy((*mMap.MMap)[iOff:], p)

4
storage/mmap.go
View File

@ -55,8 +55,8 @@ func (ts *mmapTorrentStorage) Piece(p metainfo.Piece) PieceImpl {
pc: ts.pc, pc: ts.pc,
p: p, p: p,
ih: ts.infoHash, ih: ts.infoHash,
ReaderAt: io.NewSectionReader(ts.span, p.Offset(), p.Length()), ReaderAt: io.NewSectionReader(&ts.span, p.Offset(), p.Length()),
WriterAt: missinggo.NewSectionWriter(ts.span, p.Offset(), p.Length()), WriterAt: missinggo.NewSectionWriter(&ts.span, p.Offset(), p.Length()),
} }
} }