Complete inotify IN_EXCL_UNLINK implementation in VFS2.

Events were only skipped on parent directories after their children were
unlinked; events on the unlinked file itself need to be skipped as well.

As a result, all Watches.Notify() calls need to know whether the dentry where
the call came from was unlinked.

Updates #1479.

PiperOrigin-RevId: 317979476

4 files changed, 16 insertions, 14 deletions

diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
index 0321fd384..d253c996c 100644
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ b/pkg/sentry/fsimpl/gofer/filesystem.go
@@ -375,7 +375,7 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir
 		if dir {
 			ev |= linux.IN_ISDIR
 		}
-		parent.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent)
+		parent.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent, false /* unlinked */)
 		return nil
 	}
 	if fs.opts.interop == InteropModeShared {
@@ -409,7 +409,7 @@ func (fs *filesystem) doCreateAt(ctx context.Context, rp *vfs.ResolvingPath, dir
 	if dir {
 		ev |= linux.IN_ISDIR
 	}
-	parent.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent)
+	parent.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent, false /* unlinked */)
 	return nil
 }
 
@@ -543,7 +543,7 @@ func (fs *filesystem) unlinkAt(ctx context.Context, rp *vfs.ResolvingPath, dir b
 
 	// Generate inotify events for rmdir or unlink.
 	if dir {
-		parent.watches.Notify(name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent)
+		parent.watches.Notify(name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent, true /* unlinked */)
 	} else {
 		var cw *vfs.Watches
 		if child != nil {
@@ -1040,7 +1040,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
 		}
 		childVFSFD = &fd.vfsfd
 	}
-	d.watches.Notify(name, linux.IN_CREATE, 0, vfs.PathEvent)
+	d.watches.Notify(name, linux.IN_CREATE, 0, vfs.PathEvent, false /* unlinked */)
 	return childVFSFD, nil
 }
 
diff --git a/pkg/sentry/fsimpl/gofer/gofer.go b/pkg/sentry/fsimpl/gofer/gofer.go
index c6c284ff3..b0b6d8c64 100644
--- a/pkg/sentry/fsimpl/gofer/gofer.go
+++ b/pkg/sentry/fsimpl/gofer/gofer.go
@@ -1066,9 +1066,9 @@ func (d *dentry) InotifyWithParent(events, cookie uint32, et vfs.EventType) {
 	d.fs.renameMu.RLock()
 	// The ordering below is important, Linux always notifies the parent first.
 	if d.parent != nil {
-		d.parent.watches.NotifyWithExclusions(d.name, events, cookie, et, d.isDeleted())
+		d.parent.watches.Notify(d.name, events, cookie, et, d.isDeleted())
 	}
-	d.watches.Notify("", events, cookie, et)
+	d.watches.Notify("", events, cookie, et, d.isDeleted())
 	d.fs.renameMu.RUnlock()
 }
 
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index 85d8e37b2..f766b7ce2 100644
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
@@ -182,7 +182,7 @@ func (fs *filesystem) doCreateAt(rp *vfs.ResolvingPath, dir bool, create func(pa
 	if dir {
 		ev |= linux.IN_ISDIR
 	}
-	parentDir.inode.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent)
+	parentDir.inode.watches.Notify(name, uint32(ev), 0, vfs.InodeEvent, false /* unlinked */)
 	parentDir.inode.touchCMtime()
 	return nil
 }
@@ -251,7 +251,7 @@ func (fs *filesystem) LinkAt(ctx context.Context, rp *vfs.ResolvingPath, vd vfs.
 			return syserror.EMLINK
 		}
 		i.incLinksLocked()
-		i.watches.Notify("", linux.IN_ATTRIB, 0, vfs.InodeEvent)
+		i.watches.Notify("", linux.IN_ATTRIB, 0, vfs.InodeEvent, false /* unlinked */)
 		parentDir.insertChildLocked(fs.newDentry(i), name)
 		return nil
 	})
@@ -368,7 +368,7 @@ afterTrailingSymlink:
 		if err != nil {
 			return nil, err
 		}
-		parentDir.inode.watches.Notify(name, linux.IN_CREATE, 0, vfs.PathEvent)
+		parentDir.inode.watches.Notify(name, linux.IN_CREATE, 0, vfs.PathEvent, false /* unlinked */)
 		parentDir.inode.touchCMtime()
 		return fd, nil
 	}
@@ -625,7 +625,7 @@ func (fs *filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error
 		return err
 	}
 	parentDir.removeChildLocked(child)
-	parentDir.inode.watches.Notify(name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent)
+	parentDir.inode.watches.Notify(name, linux.IN_DELETE|linux.IN_ISDIR, 0, vfs.InodeEvent, true /* unlinked */)
 	// Remove links for child, child/., and child/..
 	child.inode.decLinksLocked()
 	child.inode.decLinksLocked()
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index a85bfc968..d7f4f0779 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -259,14 +259,16 @@ func (d *dentry) InotifyWithParent(events, cookie uint32, et vfs.EventType) {
 		events |= linux.IN_ISDIR
 	}
 
+	// tmpfs never calls VFS.InvalidateDentry(), so d.vfsd.IsDead() indicates
+	// that d was deleted.
+	deleted := d.vfsd.IsDead()
+
 	d.inode.fs.mu.RLock()
 	// The ordering below is important, Linux always notifies the parent first.
 	if d.parent != nil {
-		// tmpfs never calls VFS.InvalidateDentry(), so d.vfsd.IsDead() indicates
-		// that d was deleted.
-		d.parent.inode.watches.NotifyWithExclusions(d.name, events, cookie, et, d.vfsd.IsDead())
+		d.parent.inode.watches.Notify(d.name, events, cookie, et, deleted)
 	}
-	d.inode.watches.Notify("", events, cookie, et)
+	d.inode.watches.Notify("", events, cookie, et, deleted)
 	d.inode.fs.mu.RUnlock()
 }