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589a0afa8c
By default, if a user requests a bind mount it uses private propagation. When the source path is a path within the daemon root this, along with some other propagation values that the user can use, causes issues when the daemon tries to remove a mountpoint because a container will then have a private reference to that mount which prevents removal. Unmouting with MNT_DETATCH can help this scenario on newer kernels, but ultimately this is just covering up the problem and doesn't actually free up the underlying resources until all references are destroyed. This change does essentially 2 things: 1. Change the default propagation when unspecified to `rslave` when the source path is within the daemon root path or a parent of the daemon root (because everything is using rbinds). 2. Creates a validation error on create when the user tries to specify an unacceptable propagation mode for these paths... basically the only two acceptable modes are `rslave` and `rshared`. In cases where we have used the new default propagation but the underlying filesystem is not setup to handle it (fs must hvae at least rshared propagation) instead of erroring out like we normally would, this falls back to the old default mode of `private`, which preserves backwards compatibility. Signed-off-by: Brian Goff <cpuguy83@gmail.com>
56 lines
1.9 KiB
Go
56 lines
1.9 KiB
Go
package daemon
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import (
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"path/filepath"
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"testing"
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"github.com/docker/docker/api/types/mount"
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)
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func TestBindDaemonRoot(t *testing.T) {
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t.Parallel()
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d := &Daemon{root: "/a/b/c/daemon"}
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for _, test := range []struct {
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desc string
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opts *mount.BindOptions
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needsProp bool
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err bool
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}{
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{desc: "nil propagation settings", opts: nil, needsProp: true, err: false},
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{desc: "empty propagation settings", opts: &mount.BindOptions{}, needsProp: true, err: false},
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{desc: "private propagation", opts: &mount.BindOptions{Propagation: mount.PropagationPrivate}, err: true},
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{desc: "rprivate propagation", opts: &mount.BindOptions{Propagation: mount.PropagationRPrivate}, err: true},
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{desc: "slave propagation", opts: &mount.BindOptions{Propagation: mount.PropagationSlave}, err: true},
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{desc: "rslave propagation", opts: &mount.BindOptions{Propagation: mount.PropagationRSlave}, err: false, needsProp: false},
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{desc: "shared propagation", opts: &mount.BindOptions{Propagation: mount.PropagationShared}, err: true},
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{desc: "rshared propagation", opts: &mount.BindOptions{Propagation: mount.PropagationRSlave}, err: false, needsProp: false},
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} {
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t.Run(test.desc, func(t *testing.T) {
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test := test
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for desc, source := range map[string]string{
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"source is root": d.root,
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"source is subpath": filepath.Join(d.root, "a", "b"),
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"source is parent": filepath.Dir(d.root),
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"source is /": "/",
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} {
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t.Run(desc, func(t *testing.T) {
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mount := mount.Mount{
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Type: mount.TypeBind,
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Source: source,
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BindOptions: test.opts,
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}
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needsProp, err := d.validateBindDaemonRoot(mount)
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if (err != nil) != test.err {
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t.Fatalf("expected err=%v, got: %v", test.err, err)
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}
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if test.err {
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return
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}
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if test.needsProp != needsProp {
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t.Fatalf("expected needsProp=%v, got: %v", test.needsProp, needsProp)
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}
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})
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}
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})
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}
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}
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