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Diffstat (limited to 'pkg/sentry/vfs/filesystem.go')
-rw-r--r--pkg/sentry/vfs/filesystem.go22
1 files changed, 22 insertions, 0 deletions
diff --git a/pkg/sentry/vfs/filesystem.go b/pkg/sentry/vfs/filesystem.go
index 76ff8cf51..dfbd2372a 100644
--- a/pkg/sentry/vfs/filesystem.go
+++ b/pkg/sentry/vfs/filesystem.go
@@ -47,6 +47,9 @@ func (fs *Filesystem) Init(vfsObj *VirtualFilesystem, impl FilesystemImpl) {
fs.refs = 1
fs.vfs = vfsObj
fs.impl = impl
+ vfsObj.filesystemsMu.Lock()
+ vfsObj.filesystems[fs] = struct{}{}
+ vfsObj.filesystemsMu.Unlock()
}
// VirtualFilesystem returns the containing VirtualFilesystem.
@@ -66,9 +69,28 @@ func (fs *Filesystem) IncRef() {
}
}
+// TryIncRef increments fs' reference count and returns true. If fs' reference
+// count is zero, TryIncRef does nothing and returns false.
+//
+// TryIncRef does not require that a reference is held on fs.
+func (fs *Filesystem) TryIncRef() bool {
+ for {
+ refs := atomic.LoadInt64(&fs.refs)
+ if refs <= 0 {
+ return false
+ }
+ if atomic.CompareAndSwapInt64(&fs.refs, refs, refs+1) {
+ return true
+ }
+ }
+}
+
// DecRef decrements fs' reference count.
func (fs *Filesystem) DecRef() {
if refs := atomic.AddInt64(&fs.refs, -1); refs == 0 {
+ fs.vfs.filesystemsMu.Lock()
+ delete(fs.vfs.filesystems, fs)
+ fs.vfs.filesystemsMu.Unlock()
fs.impl.Release()
} else if refs < 0 {
panic("Filesystem.decRef() called without holding a reference")