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https://github.com/containers/podman.git
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fc6dcd12b3
We added the concept of image volumes in 2.2.0, to support inspecting an image from within a container. However, this is a strictly read-only mount, with no modification allowed. By contrast, the new `image` volume driver creates a c/storage container as its underlying storage, so we have a read/write layer. This, in and of itself, is not especially interesting, but what it will enable in the future is. If we add a new command to allow these image volumes to be committed, we can now distribute volumes - and changes to them - via a standard OCI image registry (which is rather new and quite exciting). Future work in this area: - Add support for `podman volume push` (commit volume changes and push resulting image to OCI registry). - Add support for `podman volume pull` (currently, we require that the image a volume is created from be already pulled; it would be simpler if we had a dedicated command that did the pull and made a volume from it) - Add support for scratch images (make an empty image on demand to use as the base of the volume) - Add UOR support to `podman volume push` and `podman volume pull` to enable both with non-image volume drivers Signed-off-by: Matthew Heon <matthew.heon@pm.me>
104 lines
2.5 KiB
Go
104 lines
2.5 KiB
Go
package libpod
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import (
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"fmt"
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"os"
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"path/filepath"
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"github.com/containers/podman/v4/libpod/define"
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)
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// Creates a new volume
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func newVolume(runtime *Runtime) *Volume {
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volume := new(Volume)
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volume.config = new(VolumeConfig)
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volume.state = new(VolumeState)
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volume.runtime = runtime
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volume.config.Labels = make(map[string]string)
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volume.config.Options = make(map[string]string)
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volume.state.NeedsCopyUp = true
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volume.state.NeedsChown = true
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return volume
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}
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// teardownStorage deletes the volume from volumePath
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func (v *Volume) teardownStorage() error {
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if v.UsesVolumeDriver() {
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return nil
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}
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// TODO: Should this be converted to use v.config.MountPoint?
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return os.RemoveAll(filepath.Join(v.runtime.config.Engine.VolumePath, v.Name()))
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}
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// Volumes with options set, or a filesystem type, or a device to mount need to
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// be mounted and unmounted.
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func (v *Volume) needsMount() bool {
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// Non-local driver always needs mount
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if v.UsesVolumeDriver() {
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return true
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}
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// Image driver always needs mount
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if v.config.Driver == define.VolumeDriverImage {
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return true
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}
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// Commit 28138dafcc added the UID and GID options to this map
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// However we should only mount when options other than uid and gid are set.
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// see https://github.com/containers/podman/issues/10620
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index := 0
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if _, ok := v.config.Options["UID"]; ok {
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index++
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}
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if _, ok := v.config.Options["GID"]; ok {
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index++
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}
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if _, ok := v.config.Options["SIZE"]; ok {
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index++
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}
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if _, ok := v.config.Options["NOQUOTA"]; ok {
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index++
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}
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if _, ok := v.config.Options["nocopy"]; ok {
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index++
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}
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if _, ok := v.config.Options["copy"]; ok {
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index++
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}
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// when uid or gid is set there is also the "o" option
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// set so we have to ignore this one as well
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if index > 0 {
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index++
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}
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// Local driver with options other than uid,gid needs mount
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return len(v.config.Options) > index
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}
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// update() updates the volume state from the DB.
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func (v *Volume) update() error {
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if err := v.runtime.state.UpdateVolume(v); err != nil {
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return err
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}
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if !v.valid {
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return define.ErrVolumeRemoved
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}
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return nil
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}
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// save() saves the volume state to the DB
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func (v *Volume) save() error {
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return v.runtime.state.SaveVolume(v)
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}
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// Refresh volume state after a restart.
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func (v *Volume) refresh() error {
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lock, err := v.runtime.lockManager.AllocateAndRetrieveLock(v.config.LockID)
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if err != nil {
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return fmt.Errorf("acquiring lock %d for volume %s: %w", v.config.LockID, v.Name(), err)
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}
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v.lock = lock
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return nil
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}
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