diff --git a/services/device/device/debug.go b/services/device/device/debug.go
index 1ba6fc4..1b06b3c 100644
--- a/services/device/device/debug.go
+++ b/services/device/device/debug.go
@@ -15,7 +15,6 @@
 )
 
 var cmdDebug = &cmdline.Command{
-	Runner:   globRunner(runDebug),
 	Name:     "debug",
 	Short:    "Debug the device.",
 	Long:     "Get internal debug information about application installations and instances.",
@@ -24,6 +23,10 @@
 <app name patterns...> are vanadium object names or glob name patterns corresponding to application installations and instances.`,
 }
 
+func init() {
+	globify(cmdDebug, runDebug, new(globSettings))
+}
+
 func runDebug(entry globResult, ctx *context.T, stdout, _ io.Writer) error {
 	if description, err := device.DeviceClient(entry.name).Debug(ctx); err != nil {
 		return fmt.Errorf("Debug failed: %v", err)
diff --git a/services/device/device/doc.go b/services/device/device/doc.go
index 816a5c1..b42ff11 100644
--- a/services/device/device/doc.go
+++ b/services/device/device/doc.go
@@ -46,14 +46,6 @@
    user specified by this flag
  -dryrun=false
    Elides root-requiring systemcalls.
- -installation-state=
-   If non-empty, specifies allowed installation states (all others installations
-   get filtered out). The value of the flag is a comma-separated list of values
-   from among: [Active Uninstalled].
- -instance-state=
-   If non-empty, specifies allowed instance states (all other instances get
-   filtered out). The value of the flag is a comma-separated list of values from
-   among: [Launching Running Dying NotRunning Updating Deleted].
  -kill=false
    Kill process ids given as command-line arguments.
  -log_backtrace_at=:0
@@ -68,13 +60,6 @@
    max size in bytes of the buffer to use for logging stack traces
  -minuid=501
    UIDs cannot be less than this number.
- -only-installations=false
-   If set, only consider installations.
- -only-instances=false
-   If set, only consider instances.
- -parallelism=BYKIND
-   Specifies the level of parallelism for the handler execution. One of:
-   BYKIND,FULL,NONE
  -progname=unnamed_app
    Visible name of the application, used in argv[0]
  -rm=false
@@ -289,41 +274,109 @@
 previous version of their current version
 
 Usage:
-   device revert <name patterns...>
+   device revert [flags] <name patterns...>
 
 <name patterns...> are vanadium object names or glob name patterns corresponding
 to the device manager service, or to application installations and instances.
 
+The device revert flags are:
+ -installation-state=
+   If non-empty, specifies allowed installation states (all others installations
+   get filtered out). The value of the flag is a comma-separated list of values
+   from among: [Active Uninstalled].
+ -instance-state=
+   If non-empty, specifies allowed instance states (all other instances get
+   filtered out). The value of the flag is a comma-separated list of values from
+   among: [Launching Running Dying NotRunning Updating Deleted].
+ -only-installations=false
+   If set, only consider installations.
+ -only-instances=false
+   If set, only consider instances.
+ -parallelism=BYKIND
+   Specifies the level of parallelism for the handler execution. One of: [BYKIND
+   FULL NONE].
+
 Device update
 
 Update the device manager or application instances and installations
 
 Usage:
-   device update <name patterns...>
+   device update [flags] <name patterns...>
 
 <name patterns...> are vanadium object names or glob name patterns corresponding
 to the device manager service, or to application installations and instances.
 
+The device update flags are:
+ -installation-state=
+   If non-empty, specifies allowed installation states (all others installations
+   get filtered out). The value of the flag is a comma-separated list of values
+   from among: [Active Uninstalled].
+ -instance-state=
+   If non-empty, specifies allowed instance states (all other instances get
+   filtered out). The value of the flag is a comma-separated list of values from
+   among: [Launching Running Dying NotRunning Updating Deleted].
+ -only-installations=false
+   If set, only consider installations.
+ -only-instances=false
+   If set, only consider instances.
+ -parallelism=BYKIND
+   Specifies the level of parallelism for the handler execution. One of: [BYKIND
+   FULL NONE].
+
 Device status
 
 Get the status of the device manager or application instances and installations.
 
 Usage:
-   device status <name patterns...>
+   device status [flags] <name patterns...>
 
 <name patterns...> are vanadium object names or glob name patterns corresponding
 to the device manager service, or to application installations and instances.
 
+The device status flags are:
+ -installation-state=
+   If non-empty, specifies allowed installation states (all others installations
+   get filtered out). The value of the flag is a comma-separated list of values
+   from among: [Active Uninstalled].
+ -instance-state=
+   If non-empty, specifies allowed instance states (all other instances get
+   filtered out). The value of the flag is a comma-separated list of values from
+   among: [Launching Running Dying NotRunning Updating Deleted].
+ -only-installations=false
+   If set, only consider installations.
+ -only-instances=false
+   If set, only consider instances.
+ -parallelism=FULL
+   Specifies the level of parallelism for the handler execution. One of: [BYKIND
+   FULL NONE].
+
 Device debug
 
 Get internal debug information about application installations and instances.
 
 Usage:
-   device debug <app name patterns...>
+   device debug [flags] <app name patterns...>
 
 <app name patterns...> are vanadium object names or glob name patterns
 corresponding to application installations and instances.
 
+The device debug flags are:
+ -installation-state=
+   If non-empty, specifies allowed installation states (all others installations
+   get filtered out). The value of the flag is a comma-separated list of values
+   from among: [Active Uninstalled].
+ -instance-state=
+   If non-empty, specifies allowed instance states (all other instances get
+   filtered out). The value of the flag is a comma-separated list of values from
+   among: [Launching Running Dying NotRunning Updating Deleted].
+ -only-installations=false
+   If set, only consider installations.
+ -only-instances=false
+   If set, only consider instances.
+ -parallelism=FULL
+   Specifies the level of parallelism for the handler execution. One of: [BYKIND
+   FULL NONE].
+
 Device acl - Tool for setting device manager Permissions
 
 The acl tool manages Permissions on the device manger, installations and
@@ -406,11 +459,28 @@
 List application installations or instances.
 
 Usage:
-   device ls <app name patterns...>
+   device ls [flags] <app name patterns...>
 
 <app name patterns...> are vanadium object names or glob name patterns
 corresponding to application installations and instances.
 
+The device ls flags are:
+ -installation-state=
+   If non-empty, specifies allowed installation states (all others installations
+   get filtered out). The value of the flag is a comma-separated list of values
+   from among: [Active Uninstalled].
+ -instance-state=
+   If non-empty, specifies allowed instance states (all other instances get
+   filtered out). The value of the flag is a comma-separated list of values from
+   among: [Launching Running Dying NotRunning Updating Deleted].
+ -only-installations=false
+   If set, only consider installations.
+ -only-instances=false
+   If set, only consider instances.
+ -parallelism=FULL
+   Specifies the level of parallelism for the handler execution. One of: [BYKIND
+   FULL NONE].
+
 Device help - Display help for commands or topics
 
 Help with no args displays the usage of the parent command.
diff --git a/services/device/device/glob.go b/services/device/device/glob.go
index 63a0e4c..523e3ec 100644
--- a/services/device/device/glob.go
+++ b/services/device/device/glob.go
@@ -33,7 +33,10 @@
 // and can be run concurrently. The handler should direct its output to the
 // given stdout and stderr writers.
 //
-// Typical usage:
+// There are three usage patterns, depending on the desired level of control
+// over the execution flow and settings manipulation.
+//
+// (1) Most control
 //
 // func myCmdHandler(entry globResult, ctx *context.T, stdout, stderr io.Writer) error {
 //   output := myCmdProcessing(entry)
@@ -43,7 +46,7 @@
 //
 // func runMyCmd(ctx *context.T, env *cmdline.Env, args []string) error {
 //   ...
-//   err := run(ctx, env, args, myCmdHandler)
+//   err := run(ctx, env, args, myCmdHandler, globSettings{})
 //   ...
 // }
 //
@@ -52,18 +55,35 @@
 //   ...
 // }
 //
-// Alternatively, if all runMyCmd does is to call run, you can use globRunner to
-// avoid having to define runMyCmd:
+// (2) Pre-packaged runner
+//
+// If all runMyCmd does is to call run, you can use globRunner to avoid having
+// to define runMyCmd:
 //
 // var cmdMyCmd = &cmdline.Command {
-//   Runner: globRunner(myCmdHandler)
+//   Runner: globRunner(myCmdHandler, &globSettings{}),
+//   Name: "mycmd",
 //   ...
 // }
+//
+// (3) Pre-packaged runner and glob settings flag configuration
+//
+// If, additionally, you want the globSettings to be configurable with
+// command-line flags, you can use globify instead:
+//
+// var cmdMyCmd = &cmdline.Command {
+//   Name: "mycmd",
+//   ...
+// }
+//
+// func init() {
+//   globify(cmdMyCmd, myCmdHandler, &globSettings{}),
+// }
 type globHandler func(entry globResult, ctx *context.T, stdout, stderr io.Writer) error
 
-func globRunner(handler globHandler) cmdline.Runner {
+func globRunner(handler globHandler, s *globSettings) cmdline.Runner {
 	return v23cmd.RunnerFunc(func(ctx *context.T, env *cmdline.Env, args []string) error {
-		return run(ctx, env, args, handler)
+		return run(ctx, env, args, handler, *s)
 	})
 }
 
@@ -113,10 +133,10 @@
 // (instance/installation) and state.  No de-duping of results is performed.
 // The outputs from each of the handlers are sorted: installations first, then
 // instances (and alphabetically by object name for each group).
-func run(ctx *context.T, env *cmdline.Env, args []string, handler globHandler) error {
+func run(ctx *context.T, env *cmdline.Env, args []string, handler globHandler, s globSettings) error {
 	results := glob(ctx, env, args)
 	sort.Sort(byTypeAndName(results))
-	results = filterResults(results)
+	results = filterResults(results, s)
 	stdouts, stderrs := make([]bytes.Buffer, len(results)), make([]bytes.Buffer, len(results))
 	var errorCounter uint32 = 0
 	perResult := func(r globResult, index int) {
@@ -126,7 +146,7 @@
 		}
 	}
 	// TODO(caprita): Add unit test logic to cover all parallelism options.
-	switch handlerParallelism {
+	switch s.handlerParallelism {
 	case fullParallelism:
 		var wg sync.WaitGroup
 		for i, r := range results {
@@ -172,16 +192,16 @@
 	return nil
 }
 
-func filterResults(results []globResult) []globResult {
+func filterResults(results []globResult, s globSettings) []globResult {
 	var ret []globResult
 	for _, r := range results {
-		switch s := r.status.(type) {
+		switch status := r.status.(type) {
 		case device.StatusInstance:
-			if onlyInstallations || !instanceStateFilter.apply(s.Value.State) {
+			if s.onlyInstallations || !s.instanceStateFilter.apply(status.Value.State) {
 				continue
 			}
 		case device.StatusInstallation:
-			if onlyInstances || !installationStateFilter.apply(s.Value.State) {
+			if s.onlyInstances || !s.installationStateFilter.apply(status.Value.State) {
 				continue
 			}
 		}
@@ -361,8 +381,6 @@
 	kindParallelism: "BYKIND",
 }
 
-const defaultParallelism = kindParallelism
-
 func init() {
 	if len(parallelismStrings) != int(sentinelParallelismFlag) {
 		panic(fmt.Sprintf("broken invariant: mismatching number of parallelism types"))
@@ -387,35 +405,52 @@
 	return fmt.Errorf("unrecognized parallelism type: %v", s)
 }
 
-var (
+type globSettings struct {
 	instanceStateFilter     instanceStateFlag
 	installationStateFilter installationStateFlag
 	onlyInstances           bool
 	onlyInstallations       bool
-	handlerParallelism      parallelismFlag = defaultParallelism
-)
+	handlerParallelism      parallelismFlag
+	defaults                *globSettings
+}
 
-func init() {
-	// NOTE: When addind new flags or changing default values, remember to
-	// also update ResetGlobFlags below.
-	flag.Var(&instanceStateFilter, "instance-state", fmt.Sprintf("If non-empty, specifies allowed instance states (all other instances get filtered out). The value of the flag is a comma-separated list of values from among: %v.", device.InstanceStateAll))
-	flag.Var(&installationStateFilter, "installation-state", fmt.Sprintf("If non-empty, specifies allowed installation states (all others installations get filtered out). The value of the flag is a comma-separated list of values from among: %v.", device.InstallationStateAll))
-	flag.BoolVar(&onlyInstances, "only-instances", false, "If set, only consider instances.")
-	flag.BoolVar(&onlyInstallations, "only-installations", false, "If set, only consider installations.")
+func (s *globSettings) reset() {
+	d := s.defaults
+	*s = *d
+	s.defaults = d
+}
+
+func (s *globSettings) setDefaults(d globSettings) {
+	s.defaults = new(globSettings)
+	*s.defaults = d
+}
+
+var allGlobSettings []*globSettings
+
+// ResetGlobSettings is meant for tests to restore the values of flag-configured
+// variables when running multiple commands in the same process.
+func ResetGlobSettings() {
+	for _, s := range allGlobSettings {
+		s.reset()
+	}
+}
+
+func defineGlobFlags(fs *flag.FlagSet, s *globSettings) {
+	fs.Var(&s.instanceStateFilter, "instance-state", fmt.Sprintf("If non-empty, specifies allowed instance states (all other instances get filtered out). The value of the flag is a comma-separated list of values from among: %v.", device.InstanceStateAll))
+	fs.Var(&s.installationStateFilter, "installation-state", fmt.Sprintf("If non-empty, specifies allowed installation states (all others installations get filtered out). The value of the flag is a comma-separated list of values from among: %v.", device.InstallationStateAll))
+	fs.BoolVar(&s.onlyInstances, "only-instances", false, "If set, only consider instances.")
+	fs.BoolVar(&s.onlyInstallations, "only-installations", false, "If set, only consider installations.")
 	var parallelismValues []string
 	for _, v := range parallelismStrings {
 		parallelismValues = append(parallelismValues, v)
 	}
 	sort.Strings(parallelismValues)
-	flag.Var(&handlerParallelism, "parallelism", "Specifies the level of parallelism for the handler execution. One of: "+strings.Join(parallelismValues, ","))
+	fs.Var(&s.handlerParallelism, "parallelism", fmt.Sprintf("Specifies the level of parallelism for the handler execution. One of: %v.", parallelismValues))
 }
 
-// ResetGlobFlags is meant for tests to restore the values of flag-configured
-// variables when running multiple commands in the same process.
-func ResetGlobFlags() {
-	instanceStateFilter = make(instanceStateFlag)
-	installationStateFilter = make(installationStateFlag)
-	onlyInstances = false
-	onlyInstallations = false
-	handlerParallelism = defaultParallelism
+func globify(c *cmdline.Command, handler globHandler, s *globSettings) {
+	s.setDefaults(*s)
+	defineGlobFlags(&c.Flags, s)
+	c.Runner = globRunner(handler, s)
+	allGlobSettings = append(allGlobSettings, s)
 }
diff --git a/services/device/device/ls.go b/services/device/device/ls.go
index 80939da..9767abc 100644
--- a/services/device/device/ls.go
+++ b/services/device/device/ls.go
@@ -14,7 +14,6 @@
 )
 
 var cmdLs = &cmdline.Command{
-	Runner:   globRunner(runLs),
 	Name:     "ls",
 	Short:    "List applications.",
 	Long:     "List application installations or instances.",
@@ -23,6 +22,10 @@
 <app name patterns...> are vanadium object names or glob name patterns corresponding to application installations and instances.`,
 }
 
+func init() {
+	globify(cmdLs, runLs, new(globSettings))
+}
+
 func runLs(entry globResult, _ *context.T, stdout, _ io.Writer) error {
 	fmt.Fprintf(stdout, "%v\n", entry.name)
 	return nil
diff --git a/services/device/device/ls_test.go b/services/device/device/ls_test.go
index 420dd05..1db54f4 100644
--- a/services/device/device/ls_test.go
+++ b/services/device/device/ls_test.go
@@ -159,6 +159,6 @@
 		if expected, got := c.expected, strings.TrimSpace(stdout.String()); got != expected {
 			t.Errorf("Unexpected output from ls. Got %q, expected %q", got, expected)
 		}
-		cmd_device.ResetGlobFlags()
+		cmd_device.ResetGlobSettings()
 	}
 }
diff --git a/services/device/device/status.go b/services/device/device/status.go
index d32430e..6123ec1 100644
--- a/services/device/device/status.go
+++ b/services/device/device/status.go
@@ -14,7 +14,6 @@
 )
 
 var cmdStatus = &cmdline.Command{
-	Runner:   globRunner(runStatus),
 	Name:     "status",
 	Short:    "Get device manager or application status.",
 	Long:     "Get the status of the device manager or application instances and installations.",
@@ -23,6 +22,10 @@
 <name patterns...> are vanadium object names or glob name patterns corresponding to the device manager service, or to application installations and instances.`,
 }
 
+func init() {
+	globify(cmdStatus, runStatus, new(globSettings))
+}
+
 func runStatus(entry globResult, _ *context.T, stdout, _ io.Writer) error {
 	switch s := entry.status.(type) {
 	case device.StatusInstance:
diff --git a/services/device/device/status_test.go b/services/device/device/status_test.go
index 4284226..0f2d8e0 100644
--- a/services/device/device/status_test.go
+++ b/services/device/device/status_test.go
@@ -69,5 +69,6 @@
 		if got, expected := appTape.Play(), []interface{}{"Status"}; !reflect.DeepEqual(expected, got) {
 			t.Errorf("invalid call sequence. Got %v, want %v", got, expected)
 		}
+		cmd_device.ResetGlobSettings()
 	}
 }
diff --git a/services/device/device/update.go b/services/device/device/update.go
index e2d1f9a..33d7ecd 100644
--- a/services/device/device/update.go
+++ b/services/device/device/update.go
@@ -20,7 +20,6 @@
 )
 
 var cmdUpdate = &cmdline.Command{
-	Runner:   globRunner(runUpdate),
 	Name:     "update",
 	Short:    "Update the device manager or applications.",
 	Long:     "Update the device manager or application instances and installations",
@@ -29,8 +28,11 @@
 <name patterns...> are vanadium object names or glob name patterns corresponding to the device manager service, or to application installations and instances.`,
 }
 
+func init() {
+	globify(cmdUpdate, runUpdate, &globSettings{handlerParallelism: kindParallelism})
+}
+
 var cmdRevert = &cmdline.Command{
-	Runner:   globRunner(runRevert),
 	Name:     "revert",
 	Short:    "Revert the device manager or applications.",
 	Long:     "Revert the device manager or application instances and installations to a previous version of their current version",
@@ -39,6 +41,10 @@
 <name patterns...> are vanadium object names or glob name patterns corresponding to the device manager service, or to application installations and instances.`,
 }
 
+func init() {
+	globify(cmdRevert, runRevert, &globSettings{handlerParallelism: kindParallelism})
+}
+
 func instanceIsRunning(ctx *context.T, von string) (bool, error) {
 	status, err := device.ApplicationClient(von).Status(ctx)
 	if err != nil {
diff --git a/services/device/device/update_test.go b/services/device/device/update_test.go
index a6f0a40..07f7616 100644
--- a/services/device/device/update_test.go
+++ b/services/device/device/update_test.go
@@ -145,7 +145,7 @@
 					t.Errorf("Unexpected stimuli for %v. Want: %v, got %v.", n, want, got)
 				}
 			}
-			cmd_device.ResetGlobFlags()
+			cmd_device.ResetGlobSettings()
 		}
 	}
 }
diff --git a/services/mounttable/mounttablelib/mounttable.go b/services/mounttable/mounttablelib/mounttable.go
index a3582ff..2885228 100644
--- a/services/mounttable/mounttablelib/mounttable.go
+++ b/services/mounttable/mounttablelib/mounttable.go
@@ -70,7 +70,6 @@
 	serverCounter      *stats.Integer
 	perUserNodeCounter *stats.Map
 	maxNodesPerUser    int64
-	userPrefixes       []string
 }
 
 var _ rpc.Dispatcher = (*mountTable)(nil)
@@ -360,7 +359,7 @@
 // findNode finds a node in the table and optionally creates a path to it.
 //
 // If a node is found, on return it and its parent are locked.
-func (mt *mountTable) findNode(ctx *context.T, call security.Call, elems []string, create bool, tags []mounttable.Tag) (*node, error) {
+func (mt *mountTable) findNode(ctx *context.T, call security.Call, elems []string, create bool, tags, ptags []mounttable.Tag) (*node, error) {
 	n, nelems, err := mt.traverse(ctx, call, elems, create)
 	if err != nil {
 		return nil, err
@@ -373,10 +372,18 @@
 		n.Unlock()
 		return nil, nil
 	}
+	// Either the node has to satisfy tags or the parent has to satisfy ptags.
 	if err := n.satisfies(mt, ctx, call, tags); err != nil {
-		n.parent.Unlock()
-		n.Unlock()
-		return nil, err
+		if ptags == nil {
+			n.parent.Unlock()
+			n.Unlock()
+			return nil, err
+		}
+		if err := n.parent.satisfies(mt, ctx, call, ptags); err != nil {
+			n.parent.Unlock()
+			n.Unlock()
+			return nil, err
+		}
 	}
 	return n, nil
 }
@@ -486,7 +493,7 @@
 	}
 
 	// Find/create node in namespace and add the mount.
-	n, werr := mt.findNode(ctx, call.Security(), ms.elems, true, mountTags)
+	n, werr := mt.findNode(ctx, call.Security(), ms.elems, true, mountTags, nil)
 	if werr != nil {
 		return werr
 	}
@@ -579,7 +586,7 @@
 func (ms *mountContext) Unmount(ctx *context.T, call rpc.ServerCall, server string) error {
 	vlog.VI(2).Infof("*********************Unmount %q, %s", ms.name, server)
 	mt := ms.mt
-	n, err := mt.findNode(ctx, call.Security(), ms.elems, false, mountTags)
+	n, err := mt.findNode(ctx, call.Security(), ms.elems, false, mountTags, nil)
 	if err != nil {
 		return err
 	}
@@ -612,8 +619,9 @@
 		return verror.New(errCantDeleteRoot, ctx)
 	}
 	mt := ms.mt
-	// Find and lock the parent node.
-	n, err := mt.findNode(ctx, call.Security(), ms.elems, false, removeTags)
+	// Find and lock the parent node and parent node.  Either the node or its parent has
+	// to satisfy removeTags.
+	n, err := mt.findNode(ctx, call.Security(), ms.elems, false, removeTags, removeTags)
 	if err != nil {
 		return err
 	}
@@ -758,7 +766,7 @@
 	go func() {
 		defer close(ch)
 		// If there was an access error, just ignore the entry, i.e., make it invisible.
-		n, err := mt.findNode(ctx, scall, ms.elems, false, nil)
+		n, err := mt.findNode(ctx, scall, ms.elems, false, nil, nil)
 		if err != nil {
 			return
 		}
@@ -793,7 +801,7 @@
 	mt := ms.mt
 
 	// Find/create node in namespace and add the mount.
-	n, err := mt.findNode(ctx, call.Security(), ms.elems, true, setTags)
+	n, err := mt.findNode(ctx, call.Security(), ms.elems, true, setTags, nil)
 	if err != nil {
 		return err
 	}
@@ -839,7 +847,7 @@
 	mt := ms.mt
 
 	// Find node in namespace and add the mount.
-	n, err := mt.findNode(ctx, call.Security(), ms.elems, false, getTags)
+	n, err := mt.findNode(ctx, call.Security(), ms.elems, false, getTags, nil)
 	if err != nil {
 		return nil, "", err
 	}
@@ -864,8 +872,7 @@
 	if !ok {
 		return "", verror.New(errTooManyNodes, ctx)
 	}
-	// If we have no prefixes defining users, don't bother with checking per user limits.
-	if len(mt.userPrefixes) != 0 && count > mt.maxNodesPerUser {
+	if count > mt.maxNodesPerUser {
 		mt.perUserNodeCounter.Incr(creator, -1)
 		return "", verror.New(errTooManyNodes, ctx)
 	}
diff --git a/services/mounttable/mounttablelib/mounttable_test.go b/services/mounttable/mounttablelib/mounttable_test.go
index a8f9e7f..21a2f29 100644
--- a/services/mounttable/mounttablelib/mounttable_test.go
+++ b/services/mounttable/mounttablelib/mounttable_test.go
@@ -17,6 +17,7 @@
 
 	"v.io/v23"
 	"v.io/v23/context"
+	"v.io/v23/conventions"
 	"v.io/v23/naming"
 	"v.io/v23/options"
 	"v.io/v23/rpc"
@@ -483,7 +484,7 @@
 		{"alice", int64(defaultMaxNodesPerUser)},
 		{"bob", int64(0)},
 		{"root", int64(0)},
-		{localUser, int64(3)},
+		{conventions.ServerUser, int64(3)},
 	}
 	for _, tc := range testcases {
 		name := "testAccessListTemplate/num-nodes-per-user/" + tc.key
@@ -601,6 +602,12 @@
 	checkExists(t, rootCtx, estr, "one/bright/day", false)
 	doDeleteNode(t, bobCtx, estr, "one/bright", true)
 	checkExists(t, rootCtx, estr, "one/bright", false)
+
+	// Make sure directory admin can delete directory children.
+	perms := access.Permissions{"Admin": access.AccessList{In: []security.BlessingPattern{"bob"}}}
+	doSetPermissions(t, bobCtx, estr, "hoohaa", perms, "", false)
+	doDeleteNode(t, rootCtx, estr, "hoohaa", true)
+	checkExists(t, rootCtx, estr, "hoohaa", false)
 }
 
 func TestServerFormat(t *testing.T) {
diff --git a/services/mounttable/mounttablelib/persistentstore.go b/services/mounttable/mounttablelib/persistentstore.go
index 0cb614d..a96eb19 100644
--- a/services/mounttable/mounttablelib/persistentstore.go
+++ b/services/mounttable/mounttablelib/persistentstore.go
@@ -131,7 +131,7 @@
 		}
 
 		elems := strings.Split(e.N, "/")
-		n, err := mt.findNode(nil, nil, elems, true, nil)
+		n, err := mt.findNode(nil, nil, elems, true, nil, nil)
 		if n != nil || err == nil {
 			n.creator = e.C
 			if e.D {
diff --git a/services/mounttable/mounttablelib/versionedpermissions.go b/services/mounttable/mounttablelib/versionedpermissions.go
index 95a044a..d4da750 100644
--- a/services/mounttable/mounttablelib/versionedpermissions.go
+++ b/services/mounttable/mounttablelib/versionedpermissions.go
@@ -8,12 +8,12 @@
 	"encoding/json"
 	"io"
 	"os"
-	"reflect"
 	"sort"
 	"strconv"
 	"strings"
 
 	"v.io/v23/context"
+	"v.io/v23/conventions"
 	"v.io/v23/security"
 	"v.io/v23/security/access"
 	"v.io/v23/services/mounttable"
@@ -143,17 +143,11 @@
 			}
 
 			// Create name and add the Permissions map to it.
-			n, err := mt.findNode(nil, nil, elems, true, nil)
+			n, err := mt.findNode(nil, nil, elems, true, nil, nil)
 			if n != nil || err == nil {
 				vlog.VI(2).Infof("added perms %v to %s", perms, name)
 				if isPattern {
 					n.permsTemplate = perms
-					// Save the pattern prefix as a prefix describing a user.
-					prefix := strings.Join(elems[:len(elems)-1], "/")
-					if prefix != "" {
-						prefix += "/"
-					}
-					mt.userPrefixes = append(mt.userPrefixes, prefix)
 				} else {
 					n.vPerms, _ = n.vPerms.Set(nil, "", perms)
 					n.explicitPermissions = true
@@ -166,37 +160,9 @@
 	return nil
 }
 
-// pickCreator returns a string matching the blessing of the user performing the creation.  We do this using
-// the user prefixes found when parsing the config.  Eventually we may need a better way to define user
-// prefixes.
-//
-// TODO(p): readdress this argument after we have some experience with real users.
+// pickCreator returns a string matching the blessing of the user performing the creation.
 func (mt *mountTable) pickCreator(ctx *context.T, call security.Call) string {
-	// For each blessing, look for one that has a matching user prefix.  The creator is the perfix
-	// plus one more element.
-	//
-	// The prefixes themselves come from the templates in the config that constrain node names to
-	// match the user.
-	blessings, _ := security.RemoteBlessingNames(ctx, call)
-	for _, b := range blessings {
-		for _, p := range mt.userPrefixes {
-			sb := string(b)
-			if !strings.HasPrefix(sb, p) {
-				continue
-			}
-			suffix := strings.TrimPrefix(sb, p)
-			elems := strings.Split(suffix, "/")
-			return p + elems[0]
-		}
-	}
-	if ctx == nil || call == nil {
-		return localUser
-	}
-	if l, r := call.LocalBlessings().PublicKey(), call.RemoteBlessings().PublicKey(); l != nil && reflect.DeepEqual(l, r) {
-		return localUser
-	}
-	if len(blessings) > 0 {
-		return blessedUser
-	}
-	return unknownUser
+	ids := conventions.GetClientUserIds(ctx, call)
+	// Replace the slashes with something else or we'll confuse the stats package.
+	return strings.Replace(ids[0], "/", "\\", 0)
 }