diff options
Diffstat (limited to 'pkg/sentry/vfs/dentry.go')
| -rw-r--r-- | pkg/sentry/vfs/dentry.go | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/pkg/sentry/vfs/dentry.go b/pkg/sentry/vfs/dentry.go index 24af13eb1..cea3e6955 100644 --- a/pkg/sentry/vfs/dentry.go +++ b/pkg/sentry/vfs/dentry.go @@ -113,12 +113,29 @@ type DentryImpl interface { // // Note that the events may not actually propagate up to the user, depending // on the event masks. - InotifyWithParent(events uint32, cookie uint32, et EventType) + InotifyWithParent(events, cookie uint32, et EventType) // Watches returns the set of inotify watches for the file corresponding to // the Dentry. Dentries that are hard links to the same underlying file // share the same watches. + // + // Watches may return nil if the dentry belongs to a FilesystemImpl that + // does not support inotify. If an implementation returns a non-nil watch + // set, it must always return a non-nil watch set. Likewise, if an + // implementation returns a nil watch set, it must always return a nil watch + // set. + // + // The caller does not need to hold a reference on the dentry. Watches() *Watches + + // OnZeroWatches is called whenever the number of watches on a dentry drops + // to zero. This is needed by some FilesystemImpls (e.g. gofer) to manage + // dentry lifetime. + // + // The caller does not need to hold a reference on the dentry. OnZeroWatches + // may acquire inotify locks, so to prevent deadlock, no inotify locks should + // be held by the caller. + OnZeroWatches() } // IncRef increments d's reference count. @@ -149,17 +166,26 @@ func (d *Dentry) isMounted() bool { return atomic.LoadUint32(&d.mounts) != 0 } -// InotifyWithParent notifies all watches on the inodes for this dentry and +// InotifyWithParent notifies all watches on the targets represented by d and // its parent of events. -func (d *Dentry) InotifyWithParent(events uint32, cookie uint32, et EventType) { +func (d *Dentry) InotifyWithParent(events, cookie uint32, et EventType) { d.impl.InotifyWithParent(events, cookie, et) } // Watches returns the set of inotify watches associated with d. +// +// Watches will return nil if d belongs to a FilesystemImpl that does not +// support inotify. func (d *Dentry) Watches() *Watches { return d.impl.Watches() } +// OnZeroWatches performs cleanup tasks whenever the number of watches on a +// dentry drops to zero. +func (d *Dentry) OnZeroWatches() { + d.impl.OnZeroWatches() +} + // The following functions are exported so that filesystem implementations can // use them. The vfs package, and users of VFS, should not call these // functions. |