fusefronted, openfiletable: move the open file table to its own package
The open file table code needs some room to grow for the upcoming FD multiplexing implementation.
This commit is contained in:
Jakob Unterwurzacher
parent
01aeace951
commit
514f515dd7
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@ -8,7 +8,6 @@ import (
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"log"
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"os"
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"sync"
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"sync/atomic"
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"syscall"
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"time"
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@ -16,6 +15,7 @@ import (
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"github.com/hanwen/go-fuse/fuse/nodefs"
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"github.com/rfjakob/gocryptfs/internal/contentenc"
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"github.com/rfjakob/gocryptfs/internal/openfiletable"
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"github.com/rfjakob/gocryptfs/internal/serialize_reads"
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"github.com/rfjakob/gocryptfs/internal/stupidgcm"
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"github.com/rfjakob/gocryptfs/internal/syscallcompat"
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@ -40,9 +40,9 @@ type file struct {
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// Content encryption helper
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contentEnc *contentenc.ContentEnc
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// Device and inode number uniquely identify the backing file
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devIno DevInoStruct
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// Entry in the open file map
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fileTableEntry *openFileEntryT
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qIno openfiletable.QIno
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// Entry in the open file table
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fileTableEntry *openfiletable.Entry
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// go-fuse nodefs.loopbackFile
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loopbackFile nodefs.File
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// Store where the last byte was written
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@ -66,15 +66,15 @@ func NewFile(fd *os.File, writeOnly bool, fs *FS) (nodefs.File, fuse.Status) {
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tlog.Warn.Printf("NewFile: Fstat on fd %d failed: %v\n", fd.Fd(), err)
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return nil, fuse.ToStatus(err)
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}
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di := DevInoFromStat(&st)
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t := openFileMap.register(di)
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qi := openfiletable.QInoFromStat(&st)
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e := openfiletable.Register(qi)
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return &file{
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fd: fd,
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writeOnly: writeOnly,
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contentEnc: fs.contentEnc,
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devIno: di,
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fileTableEntry: t,
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qIno: qi,
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fileTableEntry: e,
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loopbackFile: nodefs.NewLoopbackFile(fd),
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fs: fs,
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File: nodefs.NewDefaultFile(),
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@ -106,7 +106,7 @@ func (f *file) readFileID() ([]byte, error) {
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if err != nil {
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if err == io.EOF && n != 0 {
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tlog.Warn.Printf("ino%d: readFileID: incomplete file, got %d instead of %d bytes",
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f.devIno.ino, n, readLen)
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f.qIno.Ino, n, readLen)
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}
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return nil, err
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}
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@ -128,7 +128,7 @@ func (f *file) createHeader() (fileID []byte, err error) {
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if !f.fs.args.NoPrealloc {
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err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), 0, contentenc.HeaderLen)
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if err != nil {
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tlog.Warn.Printf("ino%d: createHeader: prealloc failed: %s\n", f.devIno.ino, err.Error())
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tlog.Warn.Printf("ino%d: createHeader: prealloc failed: %s\n", f.qIno.Ino, err.Error())
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return nil, err
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}
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}
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@ -200,10 +200,10 @@ func (f *file) doRead(off uint64, length uint64) ([]byte, fuse.Status) {
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// We do not have the information which block was corrupt here anymore,
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// but DecryptBlocks() has already logged it anyway.
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tlog.Warn.Printf("ino%d: doRead off=%d len=%d: returning corrupt data due to forcedecode",
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f.devIno.ino, off, length)
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f.qIno.Ino, off, length)
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} else {
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curruptBlockNo := firstBlockNo + f.contentEnc.PlainOffToBlockNo(uint64(len(plaintext)))
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tlog.Warn.Printf("ino%d: doRead: corrupt block #%d: %v", f.devIno.ino, curruptBlockNo, err)
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tlog.Warn.Printf("ino%d: doRead: corrupt block #%d: %v", f.qIno.Ino, curruptBlockNo, err)
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return nil, fuse.EIO
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}
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}
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@ -227,10 +227,10 @@ func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
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f.fdLock.RLock()
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defer f.fdLock.RUnlock()
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tlog.Debug.Printf("ino%d: FUSE Read: offset=%d length=%d", f.devIno.ino, len(buf), off)
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tlog.Debug.Printf("ino%d: FUSE Read: offset=%d length=%d", f.qIno.Ino, len(buf), off)
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if f.writeOnly {
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tlog.Warn.Printf("ino%d: Tried to read from write-only file", f.devIno.ino)
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tlog.Warn.Printf("ino%d: Tried to read from write-only file", f.qIno.Ino)
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return nil, fuse.EBADF
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}
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@ -245,13 +245,13 @@ func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
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}
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if status == fuse.EIO {
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tlog.Warn.Printf("ino%d: Read: returning EIO, offset=%d, length=%d", f.devIno.ino, len(buf), off)
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tlog.Warn.Printf("ino%d: Read: returning EIO, offset=%d, length=%d", f.qIno.Ino, len(buf), off)
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}
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if status != fuse.OK {
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return nil, status
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}
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tlog.Debug.Printf("ino%d: Read: status %v, returning %d bytes", f.devIno.ino, status, len(out))
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tlog.Debug.Printf("ino%d: Read: status %v, returning %d bytes", f.qIno.Ino, status, len(out))
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return fuse.ReadResultData(out), status
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}
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@ -302,7 +302,7 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
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var oldData []byte
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oldData, status = f.doRead(o, f.contentEnc.PlainBS())
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if status != fuse.OK {
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tlog.Warn.Printf("ino%d fh%d: RMW read failed: %s", f.devIno.ino, f.intFd(), status.String())
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tlog.Warn.Printf("ino%d fh%d: RMW read failed: %s", f.qIno.Ino, f.intFd(), status.String())
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return 0, status
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}
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// Modify
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@ -312,7 +312,7 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
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// Encrypt
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blockData = f.contentEnc.EncryptBlock(blockData, b.BlockNo, fileID)
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tlog.Debug.Printf("ino%d: Writing %d bytes to block #%d",
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f.devIno.ino, uint64(len(blockData))-f.contentEnc.BlockOverhead(), b.BlockNo)
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f.qIno.Ino, uint64(len(blockData))-f.contentEnc.BlockOverhead(), b.BlockNo)
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// Store output data in the writeChain
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writeChain[i] = blockData
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numOutBytes += len(blockData)
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@ -330,7 +330,7 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
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if !f.fs.args.NoPrealloc {
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err = syscallcompat.EnospcPrealloc(int(f.fd.Fd()), int64(cOff), int64(writeBuf.Len()))
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if err != nil {
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tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.devIno.ino, f.intFd(), err.Error())
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tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.qIno.Ino, f.intFd(), err.Error())
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return 0, fuse.ToStatus(err)
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}
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}
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@ -349,7 +349,7 @@ func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
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// Stat() call is very expensive.
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// The caller must "wlock.lock(f.devIno.ino)" otherwise this check would be racy.
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func (f *file) isConsecutiveWrite(off int64) bool {
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opCount := atomic.LoadUint64(&openFileMap.opCount)
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opCount := openfiletable.WriteLockCount()
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return opCount == f.lastOpCount+1 && off == f.lastWrittenOffset+1
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}
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@ -363,12 +363,12 @@ func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) {
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// The file descriptor has been closed concurrently, which also means
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// the wlock has been freed. Exit here so we don't crash trying to access
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// it.
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tlog.Warn.Printf("ino%d fh%d: Write on released file", f.devIno.ino, f.intFd())
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tlog.Warn.Printf("ino%d fh%d: Write on released file", f.qIno.Ino, f.intFd())
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return 0, fuse.EBADF
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}
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f.fileTableEntry.writeLock.Lock()
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defer f.fileTableEntry.writeLock.Unlock()
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tlog.Debug.Printf("ino%d: FUSE Write: offset=%d length=%d", f.devIno.ino, off, len(data))
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f.fileTableEntry.WriteLock.Lock()
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defer f.fileTableEntry.WriteLock.Unlock()
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tlog.Debug.Printf("ino%d: FUSE Write: offset=%d length=%d", f.qIno.Ino, off, len(data))
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// If the write creates a file hole, we have to zero-pad the last block.
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// But if the write directly follows an earlier write, it cannot create a
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// hole, and we can save one Stat() call.
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@ -380,7 +380,7 @@ func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) {
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}
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n, status := f.doWrite(data, off)
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if status.Ok() {
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f.lastOpCount = atomic.LoadUint64(&openFileMap.opCount)
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f.lastOpCount = openfiletable.WriteLockCount()
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f.lastWrittenOffset = off + int64(len(data)) - 1
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}
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return n, status
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@ -390,13 +390,13 @@ func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) {
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func (f *file) Release() {
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f.fdLock.Lock()
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if f.released {
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log.Panicf("ino%d fh%d: double release", f.devIno.ino, f.intFd())
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log.Panicf("ino%d fh%d: double release", f.qIno.Ino, f.intFd())
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}
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f.fd.Close()
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f.released = true
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f.fdLock.Unlock()
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openFileMap.unregister(f.devIno)
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openfiletable.Unregister(f.qIno)
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}
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// Flush - FUSE call
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@ -50,8 +50,8 @@ func (f *file) Allocate(off uint64, sz uint64, mode uint32) fuse.Status {
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if f.released {
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return fuse.EBADF
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}
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f.fileTableEntry.writeLock.Lock()
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defer f.fileTableEntry.writeLock.Unlock()
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f.fileTableEntry.WriteLock.Lock()
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defer f.fileTableEntry.WriteLock.Unlock()
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blocks := f.contentEnc.ExplodePlainRange(off, sz)
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firstBlock := blocks[0]
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@ -97,17 +97,17 @@ func (f *file) Truncate(newSize uint64) fuse.Status {
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defer f.fdLock.RUnlock()
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if f.released {
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// The file descriptor has been closed concurrently.
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tlog.Warn.Printf("ino%d fh%d: Truncate on released file", f.devIno.ino, f.intFd())
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tlog.Warn.Printf("ino%d fh%d: Truncate on released file", f.qIno.Ino, f.intFd())
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return fuse.EBADF
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}
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f.fileTableEntry.writeLock.Lock()
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defer f.fileTableEntry.writeLock.Unlock()
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f.fileTableEntry.WriteLock.Lock()
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defer f.fileTableEntry.WriteLock.Unlock()
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var err error
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// Common case first: Truncate to zero
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if newSize == 0 {
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err = syscall.Ftruncate(int(f.fd.Fd()), 0)
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if err != nil {
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tlog.Warn.Printf("ino%d fh%d: Ftruncate(fd, 0) returned error: %v", f.devIno.ino, f.intFd(), err)
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tlog.Warn.Printf("ino%d fh%d: Ftruncate(fd, 0) returned error: %v", f.qIno.Ino, f.intFd(), err)
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return fuse.ToStatus(err)
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}
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// Truncate to zero kills the file header
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@ -125,7 +125,7 @@ func (f *file) Truncate(newSize uint64) fuse.Status {
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oldB := float32(oldSize) / float32(f.contentEnc.PlainBS())
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newB := float32(newSize) / float32(f.contentEnc.PlainBS())
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tlog.Debug.Printf("ino%d: FUSE Truncate from %.2f to %.2f blocks (%d to %d bytes)", f.devIno.ino, oldB, newB, oldSize, newSize)
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tlog.Debug.Printf("ino%d: FUSE Truncate from %.2f to %.2f blocks (%d to %d bytes)", f.qIno.Ino, oldB, newB, oldSize, newSize)
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// File size stays the same - nothing to do
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if newSize == oldSize {
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@ -168,7 +168,7 @@ func (f *file) Truncate(newSize uint64) fuse.Status {
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func (f *file) statPlainSize() (uint64, error) {
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fi, err := f.fd.Stat()
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if err != nil {
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tlog.Warn.Printf("ino%d fh%d: statPlainSize: %v", f.devIno.ino, f.intFd(), err)
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tlog.Warn.Printf("ino%d fh%d: statPlainSize: %v", f.qIno.Ino, f.intFd(), err)
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return 0, err
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}
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cipherSz := uint64(fi.Size())
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@ -1,101 +0,0 @@
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package fusefrontend
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import (
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"sync"
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"sync/atomic"
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"syscall"
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)
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// DevInoStruct uniquely identifies a backing file through device number and
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// inode number.
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type DevInoStruct struct {
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dev uint64
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ino uint64
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}
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// DevInoFromStat fills a new DevInoStruct with the passed Stat_t info
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func DevInoFromStat(st *syscall.Stat_t) DevInoStruct {
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// Explicit cast to uint64 to prevent build problems on 32-bit platforms
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return DevInoStruct{
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dev: uint64(st.Dev),
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ino: uint64(st.Ino),
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}
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}
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func init() {
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openFileMap.entries = make(map[DevInoStruct]*openFileEntryT)
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}
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// wlock - serializes write accesses to each file (identified by inode number)
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// Writing partial blocks means we have to do read-modify-write cycles. We
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// really don't want concurrent writes there.
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// Concurrent full-block writes could actually be allowed, but are not to
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// keep the locking simple.
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var openFileMap openFileMapT
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// wlockMap - usage:
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// 1) register
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// 2) lock ... unlock ...
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// 3) unregister
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type openFileMapT struct {
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// opCount counts writeLock.Lock() calls. As every operation that modifies a file should
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// call it, this effectively serves as a write-operation counter.
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// The variable is accessed without holding any locks so atomic operations
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// must be used. It must be the first element of the struct to guarantee
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// 64-bit alignment.
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opCount uint64
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// Protects map access
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sync.Mutex
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entries map[DevInoStruct]*openFileEntryT
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}
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type opCountMutex struct {
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sync.Mutex
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// Points to the opCount variable of the parent openFileMapT
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opCount *uint64
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}
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func (o *opCountMutex) Lock() {
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o.Mutex.Lock()
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atomic.AddUint64(o.opCount, 1)
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}
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// refCntMutex - mutex with reference count
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type openFileEntryT struct {
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// Reference count
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refCnt int
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// Write lock for this inode
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writeLock *opCountMutex
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// ID is the file ID in the file header.
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ID []byte
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IDLock sync.RWMutex
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}
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// register creates an entry for "ino", or incrementes the reference count
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// if the entry already exists.
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func (w *openFileMapT) register(di DevInoStruct) *openFileEntryT {
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w.Lock()
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defer w.Unlock()
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r := w.entries[di]
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if r == nil {
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o := opCountMutex{opCount: &w.opCount}
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r = &openFileEntryT{writeLock: &o}
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w.entries[di] = r
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}
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r.refCnt++
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return r
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}
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// unregister decrements the reference count for "di" and deletes the entry if
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// the reference count has reached 0.
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func (w *openFileMapT) unregister(di DevInoStruct) {
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w.Lock()
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defer w.Unlock()
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r := w.entries[di]
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r.refCnt--
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if r.refCnt == 0 {
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delete(w.entries, di)
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}
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}
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@ -0,0 +1,111 @@
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// Package openfiletable maintains a table of currently opened files, identified
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// by the device number + inode number pair. This table is used by fusefrontend
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// to centrally store the current file ID and to lock files against concurrent
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// writes.
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package openfiletable
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import (
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"sync"
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"sync/atomic"
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"syscall"
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)
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// QIno = Qualified Inode number.
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// Uniquely identifies a backing file through the device number,
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// inode number pair.
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type QIno struct {
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// Stat_t.{Dev,Ino} is uint64 on 32- and 64-bit Linux
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Dev uint64
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Ino uint64
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}
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// QInoFromStat fills a new QIno struct with the passed Stat_t info.
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func QInoFromStat(st *syscall.Stat_t) QIno {
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return QIno{
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// There are some architectures that use 32-bit values here
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// (darwin, freebsd-32, maybe others). Add and explicit cast to make
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// this function work everywhere.
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Dev: uint64(st.Dev),
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Ino: uint64(st.Ino),
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}
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}
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// wlock - serializes write accesses to each file (identified by inode number)
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// Writing partial blocks means we have to do read-modify-write cycles. We
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// really don't want concurrent writes there.
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// Concurrent full-block writes could actually be allowed, but are not to
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// keep the locking simple.
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var t table
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func init() {
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t.entries = make(map[QIno]*Entry)
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}
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type table struct {
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// writeLockCount counts entry.writeLock.Lock() calls. As every operation that
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||||
// modifies a file should
|
||||
// call it, this effectively serves as a write-operation counter.
|
||||
// The variable is accessed without holding any locks so atomic operations
|
||||
// must be used. It must be the first element of the struct to guarantee
|
||||
// 64-bit alignment.
|
||||
writeLockCount uint64
|
||||
// Protects map access
|
||||
sync.Mutex
|
||||
// Table entries
|
||||
entries map[QIno]*Entry
|
||||
}
|
||||
|
||||
// Entry is an entry in the open file table
|
||||
type Entry struct {
|
||||
// Reference count
|
||||
refCount int
|
||||
// Write lock for this inode
|
||||
WriteLock countingMutex
|
||||
// ID is the file ID in the file header.
|
||||
ID []byte
|
||||
IDLock sync.RWMutex
|
||||
}
|
||||
|
||||
// Register creates an open file table entry for "qi" (or incrementes the
|
||||
// reference count if the entry already exists) and returns the entry.
|
||||
func Register(qi QIno) *Entry {
|
||||
t.Lock()
|
||||
defer t.Unlock()
|
||||
|
||||
e := t.entries[qi]
|
||||
if e == nil {
|
||||
e = &Entry{}
|
||||
t.entries[qi] = e
|
||||
}
|
||||
e.refCount++
|
||||
return e
|
||||
}
|
||||
|
||||
// Unregister decrements the reference count for "qi" and deletes the entry from
|
||||
// the open file table if the reference count reaches 0.
|
||||
func Unregister(qi QIno) {
|
||||
t.Lock()
|
||||
defer t.Unlock()
|
||||
|
||||
e := t.entries[qi]
|
||||
e.refCount--
|
||||
if e.refCount == 0 {
|
||||
delete(t.entries, qi)
|
||||
}
|
||||
}
|
||||
|
||||
// countingMutex incrementes t.writeLockCount on each Lock() call.
|
||||
type countingMutex struct {
|
||||
sync.Mutex
|
||||
}
|
||||
|
||||
func (c *countingMutex) Lock() {
|
||||
c.Mutex.Lock()
|
||||
atomic.AddUint64(&t.writeLockCount, 1)
|
||||
}
|
||||
|
||||
// WriteLockCount returns the write lock counter value. This value is encremented
|
||||
// each time writeLock.Lock() on a file table entry is called.
|
||||
func WriteLockCount() uint64 {
|
||||
return atomic.LoadUint64(&t.writeLockCount)
|
||||
}
|
||||
Loading…
Reference in New Issue