Fix race condition when registering files
This commit is contained in:
parent
985d852343
commit
9e98192442
GPG Key ID:
AFE384344A45E13A
85
file.go
85
file.go
@ -38,20 +38,21 @@ func mangleOpenFlags(flags uint32) (newFlags int) {
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}
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func (volume *Volume) registerFileHandle(fd int, cName, path string) int {
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handleID := -1
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volume.handlesLock.Lock()
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c := 0
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for handleID == -1 {
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_, ok := volume.file_handles.Load(c)
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for {
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_, ok := volume.fileHandles[c]
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if !ok {
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handleID = c
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break
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}
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c++
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}
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volume.file_handles.Store(handleID, &File {
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volume.fileHandles[c] = &File {
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fd: os.NewFile(uintptr(fd), cName),
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path: string([]byte(path[:])),
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})
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return handleID
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}
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volume.handlesLock.Unlock()
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return c
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}
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// readFileID loads the file header from disk and extracts the file ID.
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@ -102,12 +103,7 @@ func createHeader(fd *os.File) (fileID []byte, err error) {
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//
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// Called by Read() for normal reading,
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// by Write() and Truncate() via doWrite() for Read-Modify-Write.
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func (volume *Volume) doRead(handleID int, dst []byte, off uint64, length uint64) ([]byte, bool) {
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value, ok := volume.file_handles.Load(handleID)
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if !ok {
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return nil, false
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}
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f := value.(*File)
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func (volume *Volume) doRead(f *File, dst []byte, off uint64, length uint64) ([]byte, bool) {
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fd := f.fd
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// Get the file ID, either from the open file table, or from disk.
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var fileID []byte
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@ -183,11 +179,9 @@ func (volume *Volume) doRead(handleID int, dst []byte, off uint64, length uint64
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//
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// Empty writes do nothing and are allowed.
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func (volume *Volume) doWrite(handleID int, data []byte, off uint64) (uint32, bool) {
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value, ok := volume.file_handles.Load(handleID)
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if !ok {
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return 0, false
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}
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f := value.(*File)
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volume.handlesLock.RLock()
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f := volume.fileHandles[handleID]
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volume.handlesLock.RUnlock()
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fd := f.fd
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fileWasEmpty := false
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var fileID []byte
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@ -216,7 +210,7 @@ func (volume *Volume) doWrite(handleID int, data []byte, off uint64) (uint32, bo
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// Incomplete block -> Read-Modify-Write
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if b.IsPartial() {
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// Read
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oldData, success := volume.doRead(handleID, nil, b.BlockPlainOff(), volume.contentEnc.PlainBS())
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oldData, success := volume.doRead(f, nil, b.BlockPlainOff(), volume.contentEnc.PlainBS())
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if !success {
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return 0, false
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}
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@ -299,11 +293,9 @@ func (volume *Volume) truncateGrowFile(handleID int, oldPlainSz uint64, newPlain
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// The new size is block-aligned. In this case we can do everything ourselves
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// and avoid the call to doWrite.
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if newPlainSz%volume.contentEnc.PlainBS() == 0 {
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value, ok := volume.file_handles.Load(handleID)
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if !ok {
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return false
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}
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f := value.(*File)
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volume.handlesLock.RLock()
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f := volume.fileHandles[handleID]
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volume.handlesLock.RUnlock()
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// The file was empty, so it did not have a header. Create one.
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if oldPlainSz == 0 {
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id, err := createHeader(f.fd)
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@ -324,11 +316,9 @@ func (volume *Volume) truncateGrowFile(handleID int, oldPlainSz uint64, newPlain
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}
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func (volume *Volume) truncate(handleID int, newSize uint64) bool {
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value, ok := volume.file_handles.Load(handleID)
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if !ok {
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return false
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}
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f := value.(*File)
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volume.handlesLock.RLock()
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f := volume.fileHandles[handleID]
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volume.handlesLock.RUnlock()
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fileFD := int(f.fd.Fd())
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var err error
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// Common case first: Truncate to zero
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@ -359,7 +349,7 @@ func (volume *Volume) truncate(handleID int, newSize uint64) bool {
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lastBlockLen := newSize - plainOff
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var data []byte
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if lastBlockLen > 0 {
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data, success = volume.doRead(handleID, nil, plainOff, lastBlockLen)
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data, success = volume.doRead(f, nil, plainOff, lastBlockLen)
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if !success {
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return false
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}
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@ -459,16 +449,14 @@ func gcf_read_file(sessionID, handleID int, offset uint64, dst_buff []byte) uint
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}
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volume := value.(*Volume)
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value, ok = volume.file_handles.Load(handleID)
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if !ok {
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return 0
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}
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f := value.(*File)
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volume.handlesLock.RLock()
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f := volume.fileHandles[handleID]
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volume.handlesLock.RUnlock()
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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f.contentLock.RLock()
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defer f.contentLock.RUnlock()
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out, success := volume.doRead(handleID, dst_buff[:0], offset, uint64(length))
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out, success := volume.doRead(f, dst_buff[:0], offset, uint64(length))
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if !success {
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return 0
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} else {
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@ -490,13 +478,11 @@ func gcf_write_file(sessionID, handleID int, offset uint64, data []byte) uint32
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}
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volume := value.(*Volume)
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value, ok = volume.file_handles.Load(handleID)
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if !ok {
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return 0
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}
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f := value.(*File)
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volume.handlesLock.RLock()
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f := volume.fileHandles[handleID]
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volume.handlesLock.RUnlock()
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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defer f.fdLock.RUnlock()
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f.contentLock.Lock()
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defer f.contentLock.Unlock()
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n, _ := volume.doWrite(handleID, data, offset)
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@ -510,14 +496,13 @@ func gcf_close_file(sessionID, handleID int) {
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return
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}
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volume := value.(*Volume)
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value, ok = volume.file_handles.Load(handleID)
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if ok {
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f := value.(*File)
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f.fdLock.Lock()
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f.fd.Close()
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volume.file_handles.Delete(handleID)
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f.fdLock.Unlock()
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}
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volume.handlesLock.Lock()
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f := volume.fileHandles[handleID]
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f.fdLock.Lock()
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f.fd.Close()
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delete(volume.fileHandles, handleID)
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volume.handlesLock.Unlock()
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f.fdLock.Unlock()
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}
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//export gcf_remove_file
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17
volume.go
17
volume.go
@ -44,7 +44,8 @@ type Volume struct {
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cryptoCore *cryptocore.CryptoCore
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contentEnc *contentenc.ContentEnc
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dirCache dirCache
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file_handles sync.Map
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handlesLock sync.RWMutex
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fileHandles map[int]*File
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}
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var OpenedVolumes sync.Map
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@ -93,6 +94,7 @@ func registerNewVolume(rootCipherDir string, masterkey []byte, cf *configfile.Co
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ivLen = 0
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}
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newVolume.dirCache = dirCache{ivLen: ivLen}
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newVolume.fileHandles = make(map[int]*File)
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//find unused volumeID
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volumeID := -1
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@ -130,10 +132,15 @@ func gcf_close(volumeID int) {
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}
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volume := value.(*Volume)
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volume.cryptoCore.Wipe()
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volume.file_handles.Range(func (handleID, _ interface {}) bool {
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gcf_close_file(volumeID, handleID.(int))
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return true
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})
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volume.handlesLock.RLock()
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fileHandles := make([]int, 0, len(volume.fileHandles))
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for i := range volume.fileHandles {
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fileHandles = append(fileHandles, i)
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}
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volume.handlesLock.RUnlock()
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for i := range fileHandles {
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gcf_close_file(volumeID, i)
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}
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volume.dirCache.Clear()
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OpenedVolumes.Delete(volumeID)
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}
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