diff options
| -rw-r--r-- | pkg/sentry/fsimpl/kernfs/kernfs.go | 8 | ||||
| -rw-r--r-- | pkg/sentry/vfs/anonfs.go | 8 | ||||
| -rw-r--r-- | pkg/sentry/vfs/filesystem.go | 2 | ||||
| -rw-r--r-- | pkg/sentry/vfs/inotify.go | 42 |
4 files changed, 26 insertions, 34 deletions
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go index 55349f2a3..596de1edf 100644 --- a/pkg/sentry/fsimpl/kernfs/kernfs.go +++ b/pkg/sentry/fsimpl/kernfs/kernfs.go @@ -227,19 +227,17 @@ func (d *Dentry) destroy() { // InotifyWithParent implements vfs.DentryImpl.InotifyWithParent. // -// TODO(gvisor.dev/issue/1479): Implement inotify. +// Although Linux technically supports inotify on pseudo filesystems (inotify +// is implemented at the vfs layer), it is not particularly useful. It is left +// unimplemented until someone actually needs it. func (d *Dentry) InotifyWithParent(events, cookie uint32, et vfs.EventType) {} // Watches implements vfs.DentryImpl.Watches. -// -// TODO(gvisor.dev/issue/1479): Implement inotify. func (d *Dentry) Watches() *vfs.Watches { return nil } // OnZeroWatches implements vfs.Dentry.OnZeroWatches. -// -// TODO(gvisor.dev/issue/1479): Implement inotify. func (d *Dentry) OnZeroWatches() {} // InsertChild inserts child into the vfs dentry cache with the given name under diff --git a/pkg/sentry/vfs/anonfs.go b/pkg/sentry/vfs/anonfs.go index 746af03ec..641e3e502 100644 --- a/pkg/sentry/vfs/anonfs.go +++ b/pkg/sentry/vfs/anonfs.go @@ -300,17 +300,15 @@ func (d *anonDentry) DecRef() { // InotifyWithParent implements DentryImpl.InotifyWithParent. // -// TODO(gvisor.dev/issue/1479): Implement inotify. +// Although Linux technically supports inotify on pseudo filesystems (inotify +// is implemented at the vfs layer), it is not particularly useful. It is left +// unimplemented until someone actually needs it. func (d *anonDentry) InotifyWithParent(events, cookie uint32, et EventType) {} // Watches implements DentryImpl.Watches. -// -// TODO(gvisor.dev/issue/1479): Implement inotify. func (d *anonDentry) Watches() *Watches { return nil } // OnZeroWatches implements Dentry.OnZeroWatches. -// -// TODO(gvisor.dev/issue/1479): Implement inotify. func (d *anonDentry) OnZeroWatches() {} diff --git a/pkg/sentry/vfs/filesystem.go b/pkg/sentry/vfs/filesystem.go index 1edd584c9..6bb9ca180 100644 --- a/pkg/sentry/vfs/filesystem.go +++ b/pkg/sentry/vfs/filesystem.go @@ -524,8 +524,6 @@ type FilesystemImpl interface { // // Preconditions: vd.Mount().Filesystem().Impl() == this FilesystemImpl. PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error - - // TODO(gvisor.dev/issue/1479): inotify_add_watch() } // PrependPathAtVFSRootError is returned by implementations of diff --git a/pkg/sentry/vfs/inotify.go b/pkg/sentry/vfs/inotify.go index 6043a0566..35960394c 100644 --- a/pkg/sentry/vfs/inotify.go +++ b/pkg/sentry/vfs/inotify.go @@ -120,6 +120,7 @@ func NewInotifyFD(ctx context.Context, vfsObj *VirtualFilesystem, flags uint32) // watches and frees all resources for an inotify instance. func (i *Inotify) Release() { var ds []*Dentry + // We need to hold i.mu to avoid a race with concurrent calls to // Inotify.handleDeletion from Watches. There's no risk of Watches // accessing this Inotify after the destructor ends, because we remove all @@ -307,19 +308,6 @@ func (i *Inotify) nextWatchIDLocked() int32 { return i.nextWatchMinusOne } -// handleDeletion handles the deletion of the target of watch w. It removes w -// from i.watches and a watch removal event is generated. -func (i *Inotify) handleDeletion(w *Watch) { - i.mu.Lock() - _, found := i.watches[w.wd] - delete(i.watches, w.wd) - i.mu.Unlock() - - if found { - i.queueEvent(newEvent(w.wd, "", linux.IN_IGNORED, 0)) - } -} - // AddWatch constructs a new inotify watch and adds it to the target. It // returns the watch descriptor returned by inotify_add_watch(2). // @@ -484,8 +472,9 @@ func (w *Watches) Notify(name string, events, cookie uint32, et EventType, unlin w.mu.RUnlock() } -// HandleDeletion is called when the watch target is destroyed to emit -// the appropriate events. +// HandleDeletion is called when the watch target is destroyed. Clear the +// watch set, detach watches from the inotify instances they belong to, and +// generate the appropriate events. func (w *Watches) HandleDeletion() { w.Notify("", linux.IN_DELETE_SELF, 0, InodeEvent, true /* unlinked */) @@ -505,9 +494,23 @@ func (w *Watches) HandleDeletion() { w.ws = nil w.mu.Unlock() + // Remove each watch from its owner's watch set, and generate a corresponding + // watch removal event. for _, watch := range ws { - // TODO(gvisor.dev/issue/1479): consider refactoring this. - watch.handleDeletion() + i := watch.owner + i.mu.Lock() + _, found := i.watches[watch.wd] + delete(i.watches, watch.wd) + + // Release mutex before notifying waiters because we don't control what + // they can do. + i.mu.Unlock() + + // If watch was not found, it was removed from the inotify instance before + // we could get to it, in which case we should not generate an event. + if found { + i.queueEvent(newEvent(watch.wd, "", linux.IN_IGNORED, 0)) + } } } @@ -559,11 +562,6 @@ func (w *Watch) Notify(name string, events uint32, cookie uint32) { w.owner.queueEvent(newEvent(w.wd, name, matchedEvents, cookie)) } -// handleDeletion handles the deletion of w's target. -func (w *Watch) handleDeletion() { - w.owner.handleDeletion(w) -} - // Event represents a struct inotify_event from linux. // // +stateify savable |