34d5878185
- Add Target to mount.Mount. - Add UnmountMounts to unmount a list of mounts in reverse order. - Add UnmountRecursive to unmount deepest mount first for a given target, using moby/sys/mountinfo. Signed-off-by: Edgar Lee <edgarhinshunlee@gmail.com>
76 lines
2.4 KiB
Go
76 lines
2.4 KiB
Go
/*
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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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"context"
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"fmt"
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"os"
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"github.com/containerd/containerd/log"
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)
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var tempMountLocation = getTempDir()
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// WithTempMount mounts the provided mounts to a temp dir, and pass the temp dir to f.
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// The mounts are valid during the call to the f.
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// Finally we will unmount and remove the temp dir regardless of the result of f.
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func WithTempMount(ctx context.Context, mounts []Mount, f func(root string) error) (err error) {
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root, uerr := os.MkdirTemp(tempMountLocation, "containerd-mount")
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if uerr != nil {
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return fmt.Errorf("failed to create temp dir: %w", uerr)
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}
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// We use Remove here instead of RemoveAll.
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// The RemoveAll will delete the temp dir and all children it contains.
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// When the Unmount fails, RemoveAll will incorrectly delete data from
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// the mounted dir. However, if we use Remove, even though we won't
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// successfully delete the temp dir and it may leak, we won't loss data
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// from the mounted dir.
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// For details, please refer to #1868 #1785.
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defer func() {
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if uerr = os.Remove(root); uerr != nil {
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log.G(ctx).WithError(uerr).WithField("dir", root).Error("failed to remove mount temp dir")
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}
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}()
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// We should do defer first, if not we will not do Unmount when only a part of Mounts are failed.
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defer func() {
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if uerr = UnmountMounts(mounts, root, 0); uerr != nil {
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uerr = fmt.Errorf("failed to unmount %s: %w", root, uerr)
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if err == nil {
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err = uerr
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} else {
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err = fmt.Errorf("%s: %w", uerr.Error(), err)
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}
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}
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}()
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if uerr = All(mounts, root); uerr != nil {
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return fmt.Errorf("failed to mount %s: %w", root, uerr)
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}
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if err := f(root); err != nil {
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return fmt.Errorf("mount callback failed on %s: %w", root, err)
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}
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return nil
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}
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func getTempDir() string {
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if xdg := os.Getenv("XDG_RUNTIME_DIR"); xdg != "" {
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return xdg
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}
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return os.TempDir()
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}
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