276 lines
8.5 KiB
Go
276 lines
8.5 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fs_test
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import (
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"reflect"
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"testing"
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"gvisor.dev/gvisor/pkg/sentry/context"
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"gvisor.dev/gvisor/pkg/sentry/fs"
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"gvisor.dev/gvisor/pkg/sentry/fs/fsutil"
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"gvisor.dev/gvisor/pkg/sentry/fs/ramfs"
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"gvisor.dev/gvisor/pkg/sentry/kernel/contexttest"
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)
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func TestReaddir(t *testing.T) {
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ctx := contexttest.Context(t)
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ctx = &rootContext{
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Context: ctx,
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root: fs.NewDirent(ctx, newTestRamfsDir(ctx, nil, nil), "root"),
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}
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for _, test := range []struct {
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// Test description.
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desc string
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// Lookup parameters.
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dir *fs.Inode
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// Want from lookup.
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err error
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names []string
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}{
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{
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desc: "no upper, lower has entries",
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dir: fs.NewTestOverlayDir(ctx,
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nil, /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{name: "a"},
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{name: "b"},
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}, nil), /* lower */
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false /* revalidate */),
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names: []string{".", "..", "a", "b"},
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},
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{
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desc: "upper has entries, no lower",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{name: "a"},
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{name: "b"},
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}, nil), /* upper */
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nil, /* lower */
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false /* revalidate */),
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names: []string{".", "..", "a", "b"},
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},
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{
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desc: "upper and lower, entries combine",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{name: "a"},
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}, nil), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{name: "b"},
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}, nil), /* lower */
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false /* revalidate */),
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names: []string{".", "..", "a", "b"},
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},
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{
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desc: "upper and lower, entries combine, none are masked",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{name: "a"},
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}, []string{"b"}), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{name: "c"},
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}, nil), /* lower */
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false /* revalidate */),
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names: []string{".", "..", "a", "c"},
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},
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{
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desc: "upper and lower, entries combine, upper masks some of lower",
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dir: fs.NewTestOverlayDir(ctx,
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newTestRamfsDir(ctx, []dirContent{
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{name: "a"},
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}, []string{"b"}), /* upper */
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newTestRamfsDir(ctx, []dirContent{
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{name: "b"}, /* will be masked */
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{name: "c"},
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}, nil), /* lower */
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false /* revalidate */),
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names: []string{".", "..", "a", "c"},
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},
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} {
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t.Run(test.desc, func(t *testing.T) {
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openDir, err := test.dir.GetFile(ctx, fs.NewDirent(ctx, test.dir, "stub"), fs.FileFlags{Read: true})
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if err != nil {
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t.Fatalf("GetFile got error %v, want nil", err)
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}
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stubSerializer := &fs.CollectEntriesSerializer{}
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err = openDir.Readdir(ctx, stubSerializer)
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if err != test.err {
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t.Fatalf("Readdir got error %v, want nil", err)
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}
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if err != nil {
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return
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}
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if !reflect.DeepEqual(stubSerializer.Order, test.names) {
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t.Errorf("Readdir got names %v, want %v", stubSerializer.Order, test.names)
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}
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})
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}
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}
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func TestReaddirRevalidation(t *testing.T) {
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ctx := contexttest.Context(t)
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ctx = &rootContext{
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Context: ctx,
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root: fs.NewDirent(ctx, newTestRamfsDir(ctx, nil, nil), "root"),
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}
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// Create an overlay with two directories, each with one file.
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upper := newTestRamfsDir(ctx, []dirContent{{name: "a"}}, nil)
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lower := newTestRamfsDir(ctx, []dirContent{{name: "b"}}, nil)
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overlay := fs.NewTestOverlayDir(ctx, upper, lower, true /* revalidate */)
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// Get a handle to the dirent in the upper filesystem so that we can
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// modify it without going through the dirent.
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upperDir := upper.InodeOperations.(*dir).InodeOperations.(*ramfs.Dir)
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// Check that overlay returns the files from both upper and lower.
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openDir, err := overlay.GetFile(ctx, fs.NewDirent(ctx, overlay, "stub"), fs.FileFlags{Read: true})
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if err != nil {
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t.Fatalf("GetFile got error %v, want nil", err)
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}
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ser := &fs.CollectEntriesSerializer{}
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if err := openDir.Readdir(ctx, ser); err != nil {
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t.Fatalf("Readdir got error %v, want nil", err)
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}
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got, want := ser.Order, []string{".", "..", "a", "b"}
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if !reflect.DeepEqual(got, want) {
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t.Errorf("Readdir got names %v, want %v", got, want)
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}
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// Remove "a" from the upper and add "c".
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if err := upperDir.Remove(ctx, upper, "a"); err != nil {
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t.Fatalf("error removing child: %v", err)
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}
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upperDir.AddChild(ctx, "c", fs.NewInode(ctx, fsutil.NewSimpleFileInode(ctx, fs.RootOwner, fs.FilePermissions{}, 0),
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upper.MountSource, fs.StableAttr{Type: fs.RegularFile}))
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// Seek to beginning of the directory and do the readdir again.
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if _, err := openDir.Seek(ctx, fs.SeekSet, 0); err != nil {
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t.Fatalf("error seeking to beginning of dir: %v", err)
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}
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ser = &fs.CollectEntriesSerializer{}
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if err := openDir.Readdir(ctx, ser); err != nil {
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t.Fatalf("Readdir got error %v, want nil", err)
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}
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// Readdir should return the updated children.
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got, want = ser.Order, []string{".", "..", "b", "c"}
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if !reflect.DeepEqual(got, want) {
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t.Errorf("Readdir got names %v, want %v", got, want)
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}
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}
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// TestReaddirOverlayFrozen tests that calling Readdir on an overlay file with
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// a frozen dirent tree does not make Readdir calls to the underlying files.
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func TestReaddirOverlayFrozen(t *testing.T) {
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ctx := contexttest.Context(t)
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// Create an overlay with two directories, each with two files.
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upper := newTestRamfsDir(ctx, []dirContent{{name: "upper-file1"}, {name: "upper-file2"}}, nil)
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lower := newTestRamfsDir(ctx, []dirContent{{name: "lower-file1"}, {name: "lower-file2"}}, nil)
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overlayInode := fs.NewTestOverlayDir(ctx, upper, lower, false)
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// Set that overlay as the root.
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root := fs.NewDirent(ctx, overlayInode, "root")
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ctx = &rootContext{
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Context: ctx,
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root: root,
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}
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// Check that calling Readdir on the root now returns all 4 files (2
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// from each layer in the overlay).
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rootFile, err := root.Inode.GetFile(ctx, root, fs.FileFlags{Read: true})
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if err != nil {
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t.Fatalf("root.Inode.GetFile failed: %v", err)
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}
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defer rootFile.DecRef()
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ser := &fs.CollectEntriesSerializer{}
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if err := rootFile.Readdir(ctx, ser); err != nil {
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t.Fatalf("rootFile.Readdir failed: %v", err)
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}
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if got, want := ser.Order, []string{".", "..", "lower-file1", "lower-file2", "upper-file1", "upper-file2"}; !reflect.DeepEqual(got, want) {
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t.Errorf("Readdir got names %v, want %v", got, want)
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}
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// Readdir should have been called on upper and lower.
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upperDir := upper.InodeOperations.(*dir)
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lowerDir := lower.InodeOperations.(*dir)
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if !upperDir.ReaddirCalled {
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t.Errorf("upperDir.ReaddirCalled got %v, want true", upperDir.ReaddirCalled)
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}
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if !lowerDir.ReaddirCalled {
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t.Errorf("lowerDir.ReaddirCalled got %v, want true", lowerDir.ReaddirCalled)
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}
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// Reset.
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upperDir.ReaddirCalled = false
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lowerDir.ReaddirCalled = false
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// Take references on "upper-file1" and "lower-file1", pinning them in
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// the dirent tree.
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for _, name := range []string{"upper-file1", "lower-file1"} {
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if _, err := root.Walk(ctx, root, name); err != nil {
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t.Fatalf("root.Walk(%q) failed: %v", name, err)
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}
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// Don't drop a reference on the returned dirent so that it
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// will stay in the tree.
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}
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// Freeze the dirent tree.
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root.Freeze()
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// Seek back to the beginning of the file.
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if _, err := rootFile.Seek(ctx, fs.SeekSet, 0); err != nil {
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t.Fatalf("error seeking to beginning of directory: %v", err)
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}
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// Calling Readdir on the root now will return only the pinned
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// children.
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ser = &fs.CollectEntriesSerializer{}
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if err := rootFile.Readdir(ctx, ser); err != nil {
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t.Fatalf("rootFile.Readdir failed: %v", err)
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}
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if got, want := ser.Order, []string{".", "..", "lower-file1", "upper-file1"}; !reflect.DeepEqual(got, want) {
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t.Errorf("Readdir got names %v, want %v", got, want)
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}
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// Readdir should NOT have been called on upper or lower.
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if upperDir.ReaddirCalled {
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t.Errorf("upperDir.ReaddirCalled got %v, want false", upperDir.ReaddirCalled)
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}
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if lowerDir.ReaddirCalled {
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t.Errorf("lowerDir.ReaddirCalled got %v, want false", lowerDir.ReaddirCalled)
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}
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}
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type rootContext struct {
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context.Context
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root *fs.Dirent
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}
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// Value implements context.Context.
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func (r *rootContext) Value(key interface{}) interface{} {
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switch key {
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case fs.CtxRoot:
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r.root.IncRef()
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return r.root
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default:
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return r.Context.Value(key)
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}
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}
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