gvisor/pkg/sentry/fsimpl/gofer/gofer_test.go

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// Copyright 2020 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package gofer
import (
"sync/atomic"
"testing"
"gvisor.dev/gvisor/pkg/p9"
"gvisor.dev/gvisor/pkg/sentry/contexttest"
)
func TestDestroyIdempotent(t *testing.T) {
fs := filesystem{
syncableDentries: make(map[*dentry]struct{}),
opts: filesystemOptions{
// Test relies on no dentry being held in the cache.
maxCachedDentries: 0,
},
}
ctx := contexttest.Context(t)
attr := &p9.Attr{
Mode: p9.ModeRegular,
}
mask := p9.AttrMask{
Mode: true,
Size: true,
}
parent, err := fs.newDentry(ctx, p9file{}, p9.QID{}, mask, attr)
if err != nil {
t.Fatalf("fs.newDentry(): %v", err)
}
child, err := fs.newDentry(ctx, p9file{}, p9.QID{}, mask, attr)
if err != nil {
t.Fatalf("fs.newDentry(): %v", err)
}
Remove filesystem structure from vfs.Dentry. This change: - Drastically simplifies the synchronization model: filesystem structure is both implementation-defined and implementation-synchronized. - Allows implementations of vfs.DentryImpl to use implementation-specific dentry types, reducing casts during path traversal. - Doesn't require dentries representing non-directory files to waste space on a map of children. - Allows dentry revalidation and mount lookup to be correctly ordered (fixed FIXME in fsimpl/gofer/filesystem.go). - Removes the need to have two separate maps in gofer.dentry (dentry.vfsd.children and dentry.negativeChildren) for positive and negative lookups respectively. //pkg/sentry/fsimpl/tmpfs/benchmark_test.go: name old time/op new time/op delta VFS2TmpfsStat/1-112 172ns ± 4% 165ns ± 3% -4.08% (p=0.002 n=9+9) VFS2TmpfsStat/2-112 199ns ± 3% 195ns ±10% ~ (p=0.132 n=8+9) VFS2TmpfsStat/3-112 230ns ± 2% 216ns ± 2% -6.15% (p=0.000 n=8+8) VFS2TmpfsStat/8-112 390ns ± 2% 358ns ± 4% -8.33% (p=0.000 n=9+8) VFS2TmpfsStat/64-112 2.20µs ± 3% 2.01µs ± 3% -8.48% (p=0.000 n=10+8) VFS2TmpfsStat/100-112 3.42µs ± 9% 3.08µs ± 2% -9.82% (p=0.000 n=9+8) VFS2TmpfsMountStat/1-112 278ns ± 1% 286ns ±15% ~ (p=0.712 n=8+10) VFS2TmpfsMountStat/2-112 311ns ± 4% 298ns ± 2% -4.27% (p=0.000 n=9+8) VFS2TmpfsMountStat/3-112 339ns ± 3% 330ns ± 9% ~ (p=0.070 n=8+9) VFS2TmpfsMountStat/8-112 503ns ± 3% 466ns ± 3% -7.38% (p=0.000 n=8+8) VFS2TmpfsMountStat/64-112 2.53µs ±16% 2.17µs ± 7% -14.19% (p=0.000 n=10+9) VFS2TmpfsMountStat/100-112 3.60µs ± 4% 3.30µs ± 8% -8.33% (p=0.001 n=8+9) Updates #1035 PiperOrigin-RevId: 307655892
2020-04-21 19:16:42 +00:00
parent.cacheNewChildLocked(child, "child")
child.checkCachingLocked()
if got := atomic.LoadInt64(&child.refs); got != -1 {
t.Fatalf("child.refs=%d, want: -1", got)
}
// Parent will also be destroyed when child reference is removed.
if got := atomic.LoadInt64(&parent.refs); got != -1 {
t.Fatalf("parent.refs=%d, want: -1", got)
}
child.checkCachingLocked()
child.checkCachingLocked()
}