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25ee00c494
pkg/system historically has been a bit of a kitchen-sink of things that were somewhat "system" related, but didn't have a good place for. EnsureRemoveAll() is one of those utilities. EnsureRemoveAll() is used to both unmount and remove a path, for which it depends on both github.com/moby/sys/mount, which in turn depends on github.com/moby/sys/mountinfo. pkg/system is imported in the CLI, but neither EnsureRemoveAll(), nor any of its moby/sys dependencies are used on the client side, so let's move this function somewhere else, to remove those dependencies from the CLI. I looked for plausible locations that were related; it's used in: - daemon - daemon/graphdriver/XXX/ - plugin I considered moving it into a (e.g.) "utils" package within graphdriver (but not a huge fan of "utils" packages), and given that it felt (mostly) related to cleaning up container filesystems, I decided to move it there. Some things to follow-up on after this: - Verify if this function is still needed (it feels a bit like a big hammer in a "YOLO, let's try some things just in case it fails") - Perhaps it should be integrated in `containerfs.Remove()` (so that it's used automatically) - Look if there's other implementations (and if they should be consolidated), although (e.g.) the one in containerd is a copy of ours: https://github.com/containerd/containerd/blob/v1.5.9/pkg/cri/server/helpers_linux.go#L200 Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
79 lines
1.9 KiB
Go
79 lines
1.9 KiB
Go
//go:build !darwin && !windows
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// +build !darwin,!windows
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package containerfs // import "github.com/docker/docker/pkg/containerfs"
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import (
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"os"
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"syscall"
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"time"
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"github.com/moby/sys/mount"
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"github.com/pkg/errors"
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)
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// EnsureRemoveAll wraps `os.RemoveAll` to check for specific errors that can
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// often be remedied.
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// Only use `EnsureRemoveAll` if you really want to make every effort to remove
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// a directory.
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//
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// Because of the way `os.Remove` (and by extension `os.RemoveAll`) works, there
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// can be a race between reading directory entries and then actually attempting
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// to remove everything in the directory.
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// These types of errors do not need to be returned since it's ok for the dir to
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// be gone we can just retry the remove operation.
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//
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// This should not return a `os.ErrNotExist` kind of error under any circumstances
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func EnsureRemoveAll(dir string) error {
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notExistErr := make(map[string]bool)
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// track retries
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exitOnErr := make(map[string]int)
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maxRetry := 50
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// Attempt to unmount anything beneath this dir first
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mount.RecursiveUnmount(dir)
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for {
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err := os.RemoveAll(dir)
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if err == nil {
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return nil
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}
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pe, ok := err.(*os.PathError)
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if !ok {
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return err
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}
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if os.IsNotExist(err) {
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if notExistErr[pe.Path] {
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return err
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}
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notExistErr[pe.Path] = true
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// There is a race where some subdir can be removed but after the parent
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// dir entries have been read.
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// So the path could be from `os.Remove(subdir)`
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// If the reported non-existent path is not the passed in `dir` we
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// should just retry, but otherwise return with no error.
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if pe.Path == dir {
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return nil
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}
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continue
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}
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if pe.Err != syscall.EBUSY {
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return err
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}
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if e := mount.Unmount(pe.Path); e != nil {
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return errors.Wrapf(e, "error while removing %s", dir)
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}
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if exitOnErr[pe.Path] == maxRetry {
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return err
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}
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exitOnErr[pe.Path]++
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time.Sleep(100 * time.Millisecond)
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}
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}
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