diff options
Diffstat (limited to 'pkg/sentry/fs/fs.go')
| -rw-r--r-- | pkg/sentry/fs/fs.go | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/pkg/sentry/fs/fs.go b/pkg/sentry/fs/fs.go index b5c72990e..0ba4b7269 100644 --- a/pkg/sentry/fs/fs.go +++ b/pkg/sentry/fs/fs.go @@ -44,7 +44,7 @@ // DirentCache.mu // Locks in InodeOperations implementations or overlayEntry // Inode.Watches.mu (see `Inotify` for other lock ordering) -// MountSource.mu +// MountSource.mu // // If multiple Dirent or MountSource locks must be taken, locks in the parent must be // taken before locks in their children. @@ -60,10 +60,11 @@ import ( ) var ( - // work is a sync.WaitGroup that can be used to queue asynchronous - // operations via Do. Callers can use Barrier to ensure no operations - // are outstanding. - work sync.WaitGroup + // workMu is used to synchronize pending asynchronous work. Async work + // runs with the lock held for reading. AsyncBarrier will take the lock + // for writing, thus ensuring that all Async work completes before + // AsyncBarrier returns. + workMu sync.RWMutex // asyncError is used to store up to one asynchronous execution error. asyncError = make(chan error, 1) @@ -71,14 +72,17 @@ var ( // AsyncBarrier waits for all outstanding asynchronous work to complete. func AsyncBarrier() { - work.Wait() + workMu.Lock() + workMu.Unlock() } // Async executes a function asynchronously. +// +// Async must not be called recursively. func Async(f func()) { - work.Add(1) - go func() { // S/R-SAFE: Barrier must be called. - defer work.Done() // Ensure Done in case of panic. + workMu.RLock() + go func() { // S/R-SAFE: AsyncBarrier must be called. + defer workMu.RUnlock() // Ensure RUnlock in case of panic. f() }() } @@ -89,7 +93,7 @@ func Async(f func()) { func AsyncErrorBarrier() error { wait := make(chan struct{}, 1) go func() { // S/R-SAFE: Does not touch persistent state. - work.Wait() + AsyncBarrier() wait <- struct{}{} }() select { |