Updated the interruptfs API.
parent
94e31a27b6
commit
0796c46a9c
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@ -39,22 +39,29 @@ var fooAttrs = fuseops.InodeAttributes{
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Size: 1234,
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}
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// A file system containing exactly one file, named "foo". Reads to the file
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// always hang until interrupted. Exposes a method for synchronizing with the
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// arrival of a read.
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// A file system containing exactly one file, named "foo". ReadFile and
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// FlushFile ops can be made to hang until interrupted. Exposes a method for
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// synchronizing with the arrival of a read or a flush.
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//
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// Must be created with New.
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type InterruptFS struct {
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fuseutil.NotImplementedFileSystem
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mu sync.Mutex
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readInFlight bool
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readInFlightChanged sync.Cond
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mu sync.Mutex
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blockForReads bool // GUARDED_BY(mu)
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blockForFlushes bool // GUARDED_BY(mu)
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// Must hold the mutex when closing these.
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readReceived chan struct{}
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flushReceived chan struct{}
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}
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func New() (fs *InterruptFS) {
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fs = &InterruptFS{}
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fs.readInFlightChanged.L = &fs.mu
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fs = &InterruptFS{
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readReceived: make(chan struct{}),
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flushReceived: make(chan struct{}),
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}
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return
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}
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@ -64,15 +71,29 @@ func New() (fs *InterruptFS) {
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////////////////////////////////////////////////////////////////////////
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// Block until the first read is received.
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//
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// LOCKS_EXCLUDED(fs.mu)
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func (fs *InterruptFS) WaitForReadInFlight() {
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func (fs *InterruptFS) WaitForFirstRead() {
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<-fs.readReceived
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}
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// Block until the first flush is received.
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func (fs *InterruptFS) WaitForFirstFlush() {
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<-fs.flushReceived
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}
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// Enable blocking until interrupted for the next (and subsequent) read ops.
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func (fs *InterruptFS) EnableReadBlocking() {
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fs.mu.Lock()
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defer fs.mu.Unlock()
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for !fs.readInFlight {
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fs.readInFlightChanged.Wait()
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}
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fs.blockForReads = true
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}
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// Enable blocking until interrupted for the next (and subsequent) flush ops.
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func (fs *InterruptFS) EnableFlushBlocking() {
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fs.mu.Lock()
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defer fs.mu.Unlock()
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fs.blockForFlushes = true
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}
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////////////////////////////////////////////////////////////////////////
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@ -128,22 +149,55 @@ func (fs *InterruptFS) OpenFile(
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func (fs *InterruptFS) ReadFile(
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ctx context.Context,
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op *fuseops.ReadFileOp) (err error) {
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// Signal that a read has been received.
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fs.mu.Lock()
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fs.readInFlight = true
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fs.readInFlightChanged.Broadcast()
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shouldBlock := fs.blockForReads
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// Signal that a read has been received, if this is the first.
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select {
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case <-fs.readReceived:
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default:
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close(fs.readReceived)
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}
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fs.mu.Unlock()
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// Wait for cancellation.
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done := ctx.Done()
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if done == nil {
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panic("Expected non-nil channel.")
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// Wait for cancellation if enabled.
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if shouldBlock {
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done := ctx.Done()
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if done == nil {
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panic("Expected non-nil channel.")
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}
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<-done
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err = ctx.Err()
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}
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return
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}
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func (fs *InterruptFS) FlushFile(
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ctx context.Context,
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op *fuseops.FlushFileOp) (err error) {
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fs.mu.Lock()
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shouldBlock := fs.blockForFlushes
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// Signal that a flush has been received, if this is the first.
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select {
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case <-fs.flushReceived:
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default:
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close(fs.flushReceived)
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}
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fs.mu.Unlock()
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// Wait for cancellation if enabled.
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if shouldBlock {
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done := ctx.Done()
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if done == nil {
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panic("Expected non-nil channel.")
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}
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<-done
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err = ctx.Err()
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}
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<-done
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// Return the context's error.
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err = ctx.Err()
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return
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}
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