hardcoresushi/libgocryptfs
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fusefrontend: doWrite: no need to take HeaderLock.RLock()

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Other writers are blocked by ContentLock already.
This commit is contained in:
Jakob Unterwurzacher 2018-07-15 12:40:23 +02:00
parent bbf5b72fff
commit 55bb22bad6
1 changed files with 4 additions and 8 deletions
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12
internal/fusefrontend/file.go
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@ -266,13 +266,13 @@ func (f *File) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fus
// //
// Empty writes do nothing and are allowed. // Empty writes do nothing and are allowed.
func (f *File) doWrite(data []byte, off int64) (uint32, fuse.Status) { func (f *File) doWrite(data []byte, off int64) (uint32, fuse.Status) {
// Read header from disk, create a new one if the file is empty // If the file ID is not cached, read it from disk
f.fileTableEntry.HeaderLock.RLock()
if f.fileTableEntry.ID == nil { if f.fileTableEntry.ID == nil {
f.fileTableEntry.HeaderLock.RUnlock() // Block other readers while we mess with the file header. Other writers
// Somebody else may write the header here, but this would do no harm. // are blocked by ContentLock already.
f.fileTableEntry.HeaderLock.Lock() f.fileTableEntry.HeaderLock.Lock()
tmpID, err := f.readFileID() tmpID, err := f.readFileID()
// Write a new file header if the file is empty
if err == io.EOF { if err == io.EOF {
tmpID, err = f.createHeader() tmpID, err = f.createHeader()
} }
@ -282,11 +282,7 @@ func (f *File) doWrite(data []byte, off int64) (uint32, fuse.Status) {
} }
f.fileTableEntry.ID = tmpID f.fileTableEntry.ID = tmpID
f.fileTableEntry.HeaderLock.Unlock() f.fileTableEntry.HeaderLock.Unlock()
// The file ID may change in here. This does no harm because we
// re-read it after the RLock().
f.fileTableEntry.HeaderLock.RLock()
} }
defer f.fileTableEntry.HeaderLock.RUnlock()
// Handle payload data // Handle payload data
dataBuf := bytes.NewBuffer(data) dataBuf := bytes.NewBuffer(data)
blocks := f.contentEnc.ExplodePlainRange(uint64(off), uint64(len(data))) blocks := f.contentEnc.ExplodePlainRange(uint64(off), uint64(len(data)))