
Auto-detect longest common dir in lowerdir option and compact it if the option size is hitting one page size. If does, Use chdir + CLONE to do mount thing to avoid hitting one page argument buffer in linux kernel mount. Signed-off-by: Wei Fu <fhfuwei@163.com>
95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
// +build linux
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/*
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Copyright The containerd Authors.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package mount
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import (
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"reflect"
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"testing"
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)
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func TestLongestCommonPrefix(t *testing.T) {
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tcases := []struct {
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in []string
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expected string
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}{
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{[]string{}, ""},
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{[]string{"foo"}, "foo"},
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{[]string{"foo", "bar"}, ""},
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{[]string{"foo", "foo"}, "foo"},
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{[]string{"foo", "foobar"}, "foo"},
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{[]string{"foo", "", "foobar"}, ""},
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}
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for i, tc := range tcases {
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if got := longestCommonPrefix(tc.in); got != tc.expected {
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t.Fatalf("[%d case] expected (%s), but got (%s)", i+1, tc.expected, got)
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}
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}
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}
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func TestCompactLowerdirOption(t *testing.T) {
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tcases := []struct {
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opts []string
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commondir string
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newopts []string
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}{
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// no lowerdir or only one
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{
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[]string{"workdir=a"},
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"",
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[]string{"workdir=a"},
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},
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{
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[]string{"workdir=a", "lowerdir=b"},
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"",
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[]string{"workdir=a", "lowerdir=b"},
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},
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// >= 2 lowerdir
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{
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[]string{"lowerdir=/snapshots/1/fs:/snapshots/10/fs"},
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"/snapshots/",
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[]string{"lowerdir=1/fs:10/fs"},
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},
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{
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[]string{"lowerdir=/snapshots/1/fs:/snapshots/10/fs:/snapshots/2/fs"},
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"/snapshots/",
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[]string{"lowerdir=1/fs:10/fs:2/fs"},
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},
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// if common dir is /
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{
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[]string{"lowerdir=/snapshots/1/fs:/other_snapshots/1/fs"},
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"",
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[]string{"lowerdir=/snapshots/1/fs:/other_snapshots/1/fs"},
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},
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}
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for i, tc := range tcases {
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dir, opts := compactLowerdirOption(tc.opts)
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if dir != tc.commondir {
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t.Fatalf("[%d case] expected common dir (%s), but got (%s)", i+1, tc.commondir, dir)
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}
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if !reflect.DeepEqual(opts, tc.newopts) {
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t.Fatalf("[%d case] expected options (%v), but got (%v)", i+1, tc.newopts, opts)
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}
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}
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}
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